Kynurenine aminotransferase and its products for treating arthritis diseases

Abstract

The present invention relates to kynurenine aminotransferase, a living recombinant bacterium genetically modified to express and secrete the kynurenine aminotransferase, and / or xanthurenic acid, its derivatives, or any pharmaceutically acceptable salt or solvate of the product of the kynurenine aminotransferase for the treatment of arthritis diseases such as rheumatoid arthritis.

Description

Technical Field

[0001] The present invention relates to the field of pharmaceuticals, and more particularly to a composition for treating arthritis diseases such as rheumatoid arthritis.

Background Art

[0002] Arthritis is swelling and tenderness of one or more joints. The main symptoms of arthritis are joint pain and stiffness, which typically worsen with age.

[0003] Rheumatoid arthritis (RA) is a long-term autoimmune disease that causes pain, swelling, and stiffness in movable joints. If left untreated, this disease ultimately leads to joint destruction, accompanied by a significant increase in morbidity and mortality. The etiology of this disease is complex, involving both immunological and genetic factors. Multiple cellular players have been identified to contribute to the pathophysiology of RA, including the accumulation of autoreactive T cells and B cells in the synovium, the production of autoantibodies directed against various joint antigens, the infiltration of inflammatory macrophages into the superficial and sub-intimal layers of the synovium, and the associated increase in the production of cytokines and chemokines that contribute to the induction, activation, and persistence of synovitis.

[0004] There is no cure for RA. However, several treatment approaches have been shown to be effective in managing RA symptoms, particularly in reducing inflammation in the joints, alleviating pain, preventing or slowing joint damage, or reducing physical disability. The pharmaceuticals available to patients with RA include, for example, methotrexate, leflunomide, hydroxychloroquine, sulfasalazine, JAK inhibitors, anti-tumor necrosis factor-alpha (TNFα) compounds such as adalimumab, etanercept, and infliximab, rituximab, or azathioprine. However, these treatments are associated with various side effects (particularly an increased risk of infection and cancer), and many patients are not adequately relieved by the available treatments. Furthermore, the majority of patients are either non-responsive to current treatments or rapidly become non-responsive.

Prior Art Documents

Patent Document

[0005]

Patent Document 1

Non-Patent Document

[0006]

Non-Patent Document 1

Non-Patent Document 2

Non-Patent Document 3

Non-Patent Document 4

Non-Patent Document 5

Non-Patent Document 6

Non-Patent Document 7

Non-Patent Document 8

Non-Patent Document 9

Non-Patent Document 10

Non-Patent Document 11

Non-Patent Document 12

Non-Patent Document 13

Summary of the Invention

Problems to be Solved by the Invention

[0007] Therefore, in the treatment of arthritis diseases, especially in the treatment of RA, there is still a strong need for new drug therapies.

Means for Solving the Problems

[0008] The inventors have demonstrated herein that the administration of quinurenine aminotransferase or one of its products, namely xanthurenic acid, reduces the severity of arthritis in a murine model of collagen antibody-induced arthritis.

[0009] Therefore, the present invention is a composition for use in the treatment of arthritis diseases, comprising - quinurenine aminotransferase (KAT), - A live recombinant bacterium genetically modified to express and secrete said kynurenine aminotransferase, and / or - The product of said kynurenine aminotransferase, which is xanthurenic acid, a derivative thereof, or any pharmaceutically acceptable salt or solvate thereof A composition comprising.

[0010] The arthritis disease is preferably selected from the group consisting of rheumatoid arthritis, juvenile idiopathic arthritis, ankylosing spondylitis, cervical spondylosis, gout, psoriatic arthritis, inflammatory bowel disease arthritis, Lyme disease arthritis, septic arthritis, reactive arthritis and secondary arthritis, more preferably selected from the group consisting of rheumatoid arthritis, juvenile idiopathic arthritis, gout, psoriatic arthritis, inflammatory bowel disease arthritis, Lyme disease arthritis, septic arthritis and reactive arthritis, and even more preferably rheumatoid arthritis.

[0011] Kynurenine aminotransferase can be selected from the group consisting of human kynurenine - oxoglutarate transaminase 1 (KAT I), human kynurenine / alpha - aminoadipate aminotransferase (KAT II), human kynurenine - oxoglutarate transaminase 3 (KAT III), human mitochondrial aspartate aminotransferase (KAT IV), its orthologs, and its variants, wherein the variant has at least 80% sequence identity to human KAT I, human KAT II, human KAT III, human KAT IV, or any of its orthologs and exhibits kynurenine aminotransferase activity. Specifically, the kynurenine aminotransferase can be selected from the group consisting of human KAT II, human KAT III, human KAT IV, its orthologs, and its variants, wherein the variant has at least 80% sequence identity to human KAT II, human KAT III, human KAT IV, or any of its orthologs and exhibits kynurenine aminotransferase activity. More specifically, the kynurenine aminotransferase can be selected from the group consisting of human KAT II, its orthologs, and its variants, wherein the variant has at least 80% sequence identity to human KAT II or any of its orthologs and exhibits kynurenine aminotransferase activity.

[0012] In a specific embodiment, the kynurenine aminotransferase is selected from the group consisting of the KAT proteins of SEQ ID NOs: 1 - 32 and its variants having at least 80% sequence identity to any of the sequences of SEQ ID NOs: 1 - 32 and exhibiting kynurenine aminotransferase activity. In a more specific embodiment, the kynurenine aminotransferase is selected from the group consisting of the KAT proteins of SEQ ID NOs: 10 - 16 and its variants having at least 80% sequence identity to any of the sequences of SEQ ID NOs: 10 - 16 and exhibiting kynurenine aminotransferase activity.

[0013] The composition may contain the kynurenine aminotransferase.

[0014] Alternatively, or in addition, the composition may contain recombinant bacteria that have been genetically modified to express and secrete the kynurenine aminotransferase. Preferably, the recombinant bacteria are selected from the group consisting of bacteria belonging to the genus Allobaculum, Adlercreutzia, Anaerostipes, Bifidobacterium, Propionibacterium, Bacteroides, Eubacterium, Enterococcus, Ruminococcus, and Faecalibacterium, Escherichia coli, and lactic acid bacteria such as bacteria belonging to the genus Lactobacillus, Lactococcus, and Streptococcus.

[0015] Alternatively, or in addition, the composition may contain xanthurenic acid, a derivative thereof, or any pharmaceutically acceptable salt or solvate thereof, and the xanthurenic acid derivative is of formula (I)

[0016] [Chemical formula]

[0017] [wherein, R1, R2, and R3 are a hydrogen atom, a hydroxyl group, a halogen atom, a -CO-R8 group or a -CO2R8 group (R8 is H or C 1~10 alkyl group), -NR9R 9' (R9 and R 9' are independently a hydrogen atom or C 1~10 alkyl group), a nitro group, a cyano group, or C optionally substituted by a halogen atom1~10 alkyl, C 2~10 alkenyl or C 2~10 alkynyl group, and C which may be substituted by a halogen atom 1~10 independently selected from the group consisting of alkyloxy; R4 and R6 are independently selected from the group consisting of a hydrogen atom and a C 1~10 alkyl group; R5 is a hydroxyl group, a hydrogen atom, -NR7R 7' (wherein R7 and R 7' are independently a hydrogen atom or a C 1~10 alkyl group), a C 1~10 alkyl group, and a C 1~10 alkoxy group selected from the group consisting of] or a tautomeric form thereof.

[0018] Specifically, the xanthurenic acid derivative is R1, R2 and R3 are independently selected from the group consisting of a hydrogen atom, an oxygen atom, a halogen atom, and a C which may be substituted by a halogen atom 1~10 alkyl, C 2~10 alkenyl or C 2~10 alkynyl group; R4 and R6 are independently selected from the group consisting of a hydrogen atom and a C 1~10 alkyl group, or R4 and / or R6 are absent; R5 is a hydroxyl group, NHR7, NR7R7 and C 1~10 alkyl or alkoxy group (wherein R7 is selected from the group consisting of a hydrogen atom and a C 1~10 alkyl group), and may be a compound of formula (I).

[0019] Specifically, the xanthurenic acid derivative may be selected from the group consisting of oxo-xanthurenic acid (OXA) and di-oxo-xanthurenic acid (DOXA). Preferably, the composition contains xanthurenic acid or any pharmaceutically acceptable salt or solvate thereof.

[0020] The composition may further comprise nicotinamide adenine dinucleotide or a precursor thereof, or may be used in combination with nicotinamide adenine dinucleotide or a precursor thereof.

[0021] The present invention also relates to the use of the composition of the present invention for manufacturing a medicament for treating an arthritis disease.

[0022] The present invention further relates to a method for treating an arthritis disease in a subject, the method comprising administering the composition of the present invention to the subject.

Brief Description of the Drawings

[0023]

Figure 1A

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Figure 3B

Figure 3C

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Figure 3E

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Figure 4A

Figure 4B

Mode for Carrying Out the Invention

[0024] The inventors analyzed tryptophan metabolism in 574 treatment-naive patients with rheumatoid arthritis and 98 healthy subjects, and found a negative correlation between multiple markers of disease activity and inflammatory cytokines and xanthurenic acid (XANA) and kynurenic acid (KYNA), and furthermore, the ratio between KYNA, XANA, and their precursors, kynurenine and 3-hydroxykynurenine, respectively. The opposite was observed for kynurenine and quinolinic acid. Similar correlations were observed for the quality of life score. They also revealed a dramatic decrease in the levels of AADAT (kynurenine aminotransferase) in the sera of RA patients compared to healthy subjects. They further demonstrated that intraperitoneal administration of AADAT in a murine model of collagen antibody-induced arthritis resulted in a decrease in disease severity, as confirmed by measurement of edema swelling and histopathology. Thus, the inventors have demonstrated herein that administration of kynurenine aminotransferase represents a strong therapeutic potential for treating arthritis diseases, particularly rheumatoid arthritis.

[0025] Thus, in a first aspect, the present invention relates to a composition for use in the treatment of an arthritis disease. The present invention also relates to the use of the composition of the present invention for the manufacture of a medicament for treating an arthritis disease. Further, the present invention relates to a method for treating an arthritis disease in a subject, the method comprising administering the composition of the present invention to the subject.

[0026] The composition may contain: - quinurenine aminotransferase, and / or - live recombinant bacteria genetically modified to express and secrete said quinurenine aminotransferase, and / or - xanthurenic acid or a derivative thereof, or any pharmaceutically acceptable salt thereof Specifically, the composition may contain:

[0027] - quinurenine aminotransferase; or - live recombinant bacteria genetically modified to express and secrete said quinurenine aminotransferase; or - xanthurenic acid or a derivative thereof, or any pharmaceutically acceptable salt thereof; or - (i) quinurenine aminotransferase and (ii) live recombinant bacteria genetically modified to express and secrete said quinurenine aminotransferase; or - (i) quinurenine aminotransferase and (ii) xanthurenic acid or a derivative thereof, or any pharmaceutically acceptable salt thereof; or - (i) live recombinant bacteria genetically modified to express and secrete said quinurenine aminotransferase and (ii) xanthurenic acid or a derivative thereof, or any pharmaceutically acceptable salt thereof; or - (i) quinurenine aminotransferase, (ii) live recombinant bacteria genetically modified to express and secrete said quinurenine aminotransferase, and (iii) xanthurenic acid or a derivative thereof, or any pharmaceutically acceptable salt thereof The terms "quinurenine aminotransferase" or "KAT" as used herein refer to an enzyme that catalyzes the amino group transfer of quinurenine to form kynurenic acid and / or catalyzes the amino group transfer of 3-hydroxyquinurenine to form xanthurenic acid. The composition may contain:

[0028] ​

[0029] As used herein, "KAT activity" refers to the action of catalyzing the amino group transfer of kynurenine to form kynurenic acid, and / or the action of catalyzing the amino group transfer of 3-hydroxykynurenine to form xanthurenic acid, preferably, the catalytic action of 3-hydroxykynurenine to form xanthurenic acid. KAT activity can be evaluated by any method known to those skilled in the art. For example, KAT activity can be evaluated as described in the experimental section, i.e., in an assay based on the disappearance of kynurenine and / or 3-hydroxykynurenine. Briefly, a reaction mixture (final volume 50 μL) containing 10 mM L-kynurenine or 3-hydroxykynurenine, 2 mM α-oxoglutarate, 40 μM PLP (pyridoxal 5'-phosphate), and 0 or 1 μL of the protein to be tested, prepared in 100 mM potassium phosphate buffer (pH 7.4), is incubated at 37 °C for 15 minutes. The reaction is stopped by adding an equal volume of 30% acetic acid. The supernatant of the reaction mixture obtained by centrifugation at 3000 g for 10 minutes at 4 °C is mixed equally with Ehrlich's reagent and incubated at room temperature for 15 minutes to obtain a colorimetric reaction. In parallel, a standard range of kynurenine or 3-hydroxykynurenine from 0 μM to 1000 μM is prepared under the same conditions. The amount of kynurenine or 3-hydroxykynurenine present in the sample is measured at an OD of 492 nm using a spectrophotometer and calculated using the standard range. The disappearance of kynurenine and / or 3-hydroxykynurenine indicates that the protein exhibits KAT activity. More specifically, the disappearance of kynurenine indicates that the protein can catalyze the amino group transfer of kynurenine to form kynurenic acid, and the disappearance of 3-hydroxykynurenine indicates that the protein can catalyze the amino group transfer of 3-hydroxykynurenine to form xanthurenic acid. The production of kynurenic acid and / or xanthurenic acid can be confirmed by mass spectrometry.

[0030] Four KATs have been reported in mammals: kynurenine-oxoglutarate transaminase 1 (KAT I), kynurenine / alpha-aminoadipate aminotransferase (KAT II or AADAT), kynurenine-oxoglutarate transaminase 3 (KAT III), and mitochondrial aspartate aminotransferase (KAT IV). In the present invention, the kynurenine aminotransferase may be a human KAT or an orthologous protein. As used herein, the terms "ortholog" or "orthologous protein" refer to a functional counterpart of a protein in another species (i.e., one that exhibits KAT activity). Orthologous proteins are similar to each other because they are derived from a common ancestor. Thus, the differences in sequence between orthologs are the result of speciation. Orthologous sequences may be included in longer or shorter isoforms. Methods for identifying orthologous proteins are well known in the art.

[0031] Human kynurenine-oxoglutarate transaminase 1 (KAT I) is encoded by the gene KYAT1, also named CCBL1 (Uniprot accession number: Q16773). Three isoforms of human KAT I are produced by alternative splicing: isoform 1 (SEQ ID NO: 1), isoform 2 (SEQ ID NO: 2), and isoform 3 (SEQ ID NO: 3).

[0032] Orthologous proteins of human KAT I may also be used in the present invention. Preferably, the orthologous proteins of human KAT I used in the present invention are mammalian proteins. Examples of orthologous proteins of human KAT I that may be used in the present invention include, but are not limited to, the orthologs listed in Table 1.

[0033]

Table 1

[0034] Human kynurenine / alpha-aminoadipate aminotransferase (KAT II or AADAT) is encoded by the gene AADAT, also named KYAT2 or KAT2 (Uniprot accession number: Q8N5Z0). Two isoforms of human KAT II are produced by alternative splicing: isoform 1 (SEQ ID NO: 10) and isoform 2 (SEQ ID NO: 11).

[0035] Orthologous proteins of human KAT II may also be used in the present invention. Preferably, the orthologous proteins of human KAT II used in the present invention are mammalian proteins. Examples of orthologous proteins of human KAT II that may be used in the present invention include, but are not limited to, the orthologs listed in Table 2 (Table 2).

[0036] [Table 2]

[0037] Human kynurenine-oxoglutarate transaminase 3 (KAT III or CCBL2) is encoded by the gene KYAT3 (Uniprot accession number: Q6YP21). Three isoforms of human KAT III are produced by alternative splicing: isoform 1 (SEQ ID NO: 17), isoform 2 (SEQ ID NO: 18) and isoform 3 (SEQ ID NO: 19).

[0038] Orthologous proteins of human KAT III may also be used in the present invention. Preferably, the orthologous proteins of human KAT III used in the present invention are mammalian proteins. Examples of orthologous proteins of human KAT III that may be used in the present invention include, but are not limited to, the orthologs listed in Table 3 (Table 3).

[0039] [Table 3]

[0040] Human mitochondrial aspartate aminotransferase (KAT IV) is encoded by the gene GOT2, which is also named KYAT4 (Uniprot accession number: P00505). Two isoforms of human KAT IV are produced by alternative splicing: isoform 1 (SEQ ID NO: 26) and isoform 2 (SEQ ID NO: 27).

[0041] Orthologous proteins of human KAT IV may also be used in the present invention. Preferably, the orthologous proteins of human KAT IV used in the present invention are mammalian proteins. Examples of orthologous proteins of human KAT IV that may be used in the present invention include, but are not limited to, the orthologs listed in Table 4 (Table 4).

[0042]

Table 4

[0043] In one embodiment, the kynurenine aminotransferase contained in the composition or expressed by the recombinant bacterium is - human KAT I, human KAT II, human KAT III, human KAT IV, and their orthologs, and - variants having at least 80% sequence identity to human KAT I, human KAT II, human KAT III, human KAT IV, or any of their orthologs and exhibiting KAT activity and may be selected from the group consisting of.

[0044] Preferably, the kynurenine aminotransferase contained in the composition or expressed by the recombinant bacterium is selected from the group consisting of the KAT proteins of SEQ ID NOs: 1 to 32 and variants thereof having at least 80% sequence identity to any of the sequences of SEQ ID NOs: 1 to 32 and exhibiting KAT activity.

[0045] As used herein, the term "variant" refers to an enzyme derived from wild-type kynurenine aminotransferase, human kynurenine aminotransferase or an ortholog thereof and containing one or more (e.g., several) modifications, i.e., substitutions, insertions, and / or deletions, at one or more positions. The term "deletion" as used with respect to a position or an amino acid means that the amino acid at a particular position is missing or absent. The term "insertion" as used with respect to a position or an amino acid means that one or more amino acids are inserted adjacent to and immediately following the amino acid occupying a particular position or are present. Variants can be obtained by various techniques well known in the art. Specifically, examples of techniques for modifying a DNA sequence encoding a wild-type protein include, but are not limited to, site-directed mutagenesis, random mutagenesis, and synthetic oligonucleotide construction.

[0046] As used herein, the terms “sequence identity” or “identity” refer to the number (%) of matches (identical amino acid residues) at positions from an alignment of two polypeptide sequences. Sequence identity is determined by comparing the sequences when aligned so as to maximize overlap and identity while minimizing sequence gaps. Specifically, sequence identity can be determined using any of several mathematical global or local alignment algorithms, depending on the lengths of the two sequences. Sequences of similar length are preferably aligned using a global alignment algorithm (e.g., the Needleman and Wunsch algorithm; Needleman and Wunsch, 1970) that optimally aligns the sequences over their entire lengths, while sequences of substantially different lengths are preferably aligned using a local alignment algorithm (e.g., the Smith and Waterman algorithm (Smith and Waterman, 1981) or the Altschul algorithm (Altschul et al., 1997; Altschul et al., 2005)). Alignments for the purpose of determining the percent amino acid sequence identity can be achieved in a variety of ways within the skill in the art, e.g., using publicly available computer software available on Internet websites such as http: / / blast.ncbi.nlm.nih.gov / or http: / / www.ebi.ac.uk / Tools / emboss / . One of ordinary skill in the art can determine appropriate parameters for measuring the alignment, including any algorithm needed to achieve maximal alignment over the entire lengths of the sequences being compared.Preferably, for the purposes of this specification, the % amino acid sequence identity value refers to a value generated using a local alignment algorithm, preferably the Basic Local Alignment Search Tool (BLAST) that finds regions of local similarity between sequences and calculates the statistical significance of the match, where all search parameters are set to default values, namely, the blastp algorithm, Expect threshold = 0.05, word size = 3, Scoring matrix = BLOSUM62, Gap costs: existence = 11, extension = 1, Conditional compositional score matrix adjustment.

[0047] In another embodiment, the kynurenine aminotransferase contained in the composition or expressed by the recombinant bacterium is - human KAT II, human KAT III, human KAT IV, and their orthologs, and - variants having at least 80% sequence identity to human KAT II, human KAT III, human KAT IV, or any of their orthologs and exhibiting KAT activity selected from the group consisting of.

[0048] Preferably, the kynurenine aminotransferase contained in the composition or expressed by the recombinant bacterium is selected from the group consisting of the KAT proteins of SEQ ID NOs: 10-32 and their variants having at least 80% sequence identity to any of the sequences of SEQ ID NOs: 10-32 and exhibiting KAT activity.

[0049] In a preferred embodiment, the kynurenine aminotransferase contained in the composition or expressed by the recombinant bacterium is - human KAT II and its orthologs, and - a variant having at least 80% sequence identity to human KAT II or any ortholog thereof and exhibiting KAT activity selected from the group consisting of

[0050] Preferably, the kynurenine aminotransferase contained in the composition or expressed by the recombinant bacterium is selected from the group consisting of the KAT proteins of SEQ ID NOs: 10-16 and those variants thereof having at least 80% sequence identity to any of the sequences of SEQ ID NOs: 10-16 and exhibiting KAT activity.

[0051] In some embodiments, the kynurenine aminotransferase contained in the composition or expressed by the recombinant bacterium can be fused to another polypeptide at its N-terminus and / or C-terminus to produce a hybrid polypeptide or a fusion polypeptide. Techniques for producing fusion polypeptides are known in the art and include ligating a coding sequence encoding a variant and an additional region of another polypeptide such that they are in-frame and the expression of the fusion polypeptide is under the control of the same promoter and terminator. The additional region of the fusion polypeptide can be selected to enhance the stability of the enzyme, facilitate the secretion of the fusion protein from cells (such as a bacterial cell, an N-terminal hydrophobic signal peptide, etc.), or assist in the purification of the fusion protein. More specifically, the additional region can be a tag useful for the purification or immobilization of the enzyme. Such tags are well known to those skilled in the art and include, for example, His tag (His6), FLAG tag, HA tag (an epitope derived from the influenza protein hemagglutinin), maltose binding protein (MPB), MYC tag (an epitope derived from the human proto-oncoprotein MYC), or GST tag (small glutathione-S-transferase). The fusion polypeptide may further include a cleavage site for a protease or a chemical agent between the enzyme and the additional region. When the fusion protein is secreted, the site is cleaved to release two separate polypeptides. The kynurenine aminotransferase may be fused at its N-terminus and / or C-terminus to one or more polypeptides exhibiting distinct enzyme activities. Optionally, this may be modified (e.g., chemically, enzymatically, physically, etc.) to improve one of its characteristics such as stability or activity.

[0052] In some embodiments, the composition used in the present invention contains a kynurenine aminotransferase, i.e., a protein that exhibits KAT activity and is as defined above.

[0053] The kynurenine aminotransferase can be produced by known methods such as recombinant techniques. Specifically, it can be expressed and secreted from a host cell, preferably a recombinant bacterium as defined below or as exemplified in the examples, and isolated or purified. As used herein, the term "host cell" means any cell type that is sensitive to transformation, transfection, transduction, or the like using a nucleic acid construct or expression vector containing a polynucleotide encoding the kynurenine aminotransferase as used in the present invention, and can express the enzyme.

[0054] Specifically, the kynurenine aminotransferase can be produced by a method comprising: (a) culturing a host cell, specifically a recombinant bacterium as defined below, in a suitable culture medium under conditions suitable for expressing the kynurenine aminotransferase; and (b) recovering the kynurenine aminotransferase from the cell culture.

[0055] The host cell is cultured in a nutrient medium suitable for producing a polypeptide using methods known in the art. For example, the cells can be cultured by shake flask culture in a suitable medium and under conditions that allow the enzyme to be expressed and / or isolated, or by small-scale or large-scale fermentation (including continuous, batch, fed-batch, or solid-state fermentation) in a laboratory or industrial fermenter. The culture is carried out using procedures known in the art in a suitable nutrient medium containing a carbon and nitrogen source and inorganic salts. Suitable media are available from commercial suppliers or can be prepared from published compositions (e.g., in the catalog of the American Type Culture Collection).

[0056] The enzyme can be recovered using any method known in the art. For example, the enzyme can be recovered from the nutrient medium by conventional procedures including, but not limited to, collection, centrifugation, filtration, extraction, spray drying, evaporation, or precipitation. Optionally, the enzyme can be partially or completely purified by various procedures known in the art including, but not limited to, chromatography (e.g., ion exchange, affinity, hydrophobicity, chromatofocusing, and size exclusion), electrophoresis procedures (e.g., preparative isoelectric focusing), solubility differences (e.g., ammonium sulfate precipitation), SDS-PAGE, or extraction to obtain a substantially pure polypeptide. Preferably, the enzyme is secreted into the nutrient medium and can be recovered directly from the culture supernatant before isolation or purification.

[0057] In embodiments where the composition comprises kynurenine aminotransferase, the kynurenine aminotransferase is preferably in isolated or purified form.

[0058] As used herein, the term "isolated" with respect to a polypeptide refers to a polypeptide that is separated from at least one associated substance found in any process used to produce the preparation (e.g., separated from at least one other cellular component) or in any substance associated with the protein. For example, an isolated polypeptide typically lacks at least some of the proteins or other components of the cells, e.g., recombinant cells, that are normally associated with it, or are normally commingled with it, or are in solution with it.

[0059] As used herein, the term "purified" means that a protein is essentially free of other proteins, such as a product purified from a culture of recombinant host cells or a product purified from a non-recombinant source. The term "purified" does not require absolute purity, but rather is intended as a relative definition. This refers to a protein that is essentially free of other components when determined by analytical techniques well known in the art (e.g., a purified protein forms distinct bands in an electrophoretic gel, a chromatography eluate, and / or a medium subjected to density gradient centrifugation). A purified protein is at least 50 percent pure, usually at least 75, 80, 85, 90, 95, 96, 97, 98, 99 percent pure (e.g., mass percent on a molar basis).

[0060] The kynurenine aminotransferase can be administered in mature form or in precursor form.

[0061] The KAT used in the present invention, specifically, the KAT contained in the composition, may be variously modified. For example, one or more amino acids in the L configuration may be replaced with amino acids in the D configuration. The polypeptide may be subjected to post-translational modification and / or additional chemical modification, specifically, glycosylation, amidation, acylation, acetylation, or methylation. A protecting group may be added to the C-terminus and / or N-terminus. For example, the protecting group at the N-terminus may be acylation or acetylation, and the protecting group at the C-terminus may be amidation or esterification. The polypeptide may contain pseudopeptide bonds that confer increased resistance to peptidases, such as CHOH-CH2, NHCO, CH2-O, CH2CH2, CO-CH2, N-N, CH=CH, CH2NH, and CH2-S, instead of the "conventional" CONH peptide bond. One or more amino acids may be replaced with rare amino acids, specifically, hydroxyproline, hydroxylysine, allohydroxylysine, 6-N-methyllysine, N-ethylglycine, N-methylglycine, N-ethylasparagine, allo-isoleucine, N-methylisoleucine, N-methylvaline, pyroglutamine, and aminobutyric acid; or synthetic amino acids, specifically, ornithine, norleucine, norvaline, and cyclohexylalanine.

[0062] The present invention also extends to the use of pharmaceutically acceptable salts of such polypeptides. Pharmaceutically acceptable salts may be salts with pharmaceutically acceptable inorganic acids commonly used in the pharmaceutical field, such as hydrochloric acid, hydrobromic acid, sulfuric acid, and phosphoric acid; salts with pharmaceutically acceptable organic acids, such as acetic acid, citric acid, maleic acid, malic acid, succinic acid, ascorbic acid, and tartaric acid; salts with pharmaceutically acceptable inorganic bases, such as sodium, potassium, calcium, magnesium, or ammonium salts; or salts with organic bases having salt-forming nitrogen. Methods for preparing these salts are well known to those skilled in the art.

[0063] The composition used in the present invention may contain one or several KAT enzymes, that is, (i) - Human KAT I, Human KAT II, Human KAT III, Human KAT IV, and their orthologs, and - Variants having at least 80% sequence identity to Human KAT I, Human KAT II, Human KAT III, Human KAT IV, or any of their orthologs and exhibiting KAT activity; selected from the group consisting of, or (ii) - Human KAT II, Human KAT III, Human KAT IV, and their orthologs, and - Variants having at least 80% sequence identity to Human KAT II, Human KAT III, Human KAT IV, or any of their orthologs and exhibiting KAT activity selected from the group consisting of, or (iii) - Human KAT II and its orthologs, and - Variants having at least 80% sequence identity to Human KAT II, or any of its orthologs and exhibiting KAT activity selected from the group consisting of, may comprise one or several KAT enzymes.

[0064] Preferably, the pharmaceutical composition used in the present invention - Human KAT II and its orthologs, and - Variants having at least 80% sequence identity to Human KAT II, or any of its orthologs and exhibiting KAT activity selected from the group consisting of, comprises one or several KAT enzymes.

[0065] In some embodiments, the composition used in the present invention comprises recombinant bacteria that are genetically modified to express and secrete quinurenine aminotransferase, i.e., a protein exhibiting KAT activity and as defined above.

[0066] As used herein, the terms "recombinant bacterium" or "genetically modified bacterium" refer to a bacterium that does not occur naturally and contains a genome modified as a result of any deletion, insertion or modification of its genetic elements. Specifically, this term refers to a bacterium containing a heterologous nucleic acid, expression cassette or vector as described below, i.e., a nucleic acid, cassette or vector that does not occur naturally in said bacterium.

[0067] As used herein, the term "endogenous" with respect to a bacterium refers to a genetic element or protein that occurs naturally in said bacterium. The term "heterologous" with respect to a bacterium refers to a genetic element or protein that does not occur naturally in said bacterium.

[0068] The recombinant bacterium used in the present invention is genetically modified by introducing a heterologous expression cassette or vector containing a nucleic acid encoding a KAT enzyme as defined above.

[0069] The nucleic acid encoding the KAT enzyme can be derived from the protein sequence, and the codon usage can be adapted according to the bacterium in which the nucleic acid is transcribed. These steps can be carried out by methods well known to those skilled in the art, some of which are described in the reference manual Sambrook et al. (Sambrook J, Russell D (2001) Molecular cloning: a laboratory manual, Third Edition Cold Spring Harbor).

[0070] As used herein, an expression cassette comprises a nucleic acid encoding a KAT enzyme as defined above, operably linked to one or more control sequences that direct the expression of said nucleic acid in a recombinant bacterium under conditions compatible with the control sequences.

[0071] The control array may include a promoter recognized by recombinant bacteria. The promoter contains a transcriptional control array that mediates the expression of the KAT enzyme. The promoter may be any polynucleotide that exhibits transcriptional activity in recombinant bacteria, including mutants, shortened forms, and hybrid promoters, and can be obtained from a gene encoding an extracellular or intracellular polypeptide that is either homologous or heterologous to the bacteria. The promoter may be a strong, weak, constitutive, or inducible promoter. Usually, the promoter is heterologous to the nucleic acid encoding the KAT enzyme, i.e., it was not originally operably linked to said nucleic acid or was originally operably linked at a different position. The promoter should be selected to exhibit transcriptional activity in recombinant bacteria.

[0072] Examples of suitable promoters include, but are not limited to, constitutive promoters such as P21, P23, P32, P44, or P59 (Morello et al., J Mol Microbiol Biotechnol 2008;14:48-58) or inducible promoters such as the nisin-inducible control gene expression (NICE) system obtained from the nis (nisABTCIPRKEFG) operon present in some Lactococcus lactis strains (Kuipers et al., J Biotechnol 1998;64:15-21).

[0073] The control array may be a transcription terminator recognized by bacteria to terminate transcription. The terminator is operably linked to the 3' end of the nucleic acid encoding the KAT enzyme. Any terminator functional in bacteria can be used in the present invention. Usually, the terminator is selected in correlation with the promoter. Examples of suitable terminators include, but are not limited to, the rho-independent transcription terminator trpA (Christie et al., 1981, Proc. Natl. Acad. Sci. USA 78: 4180-4184), the terminal region of the rrnB gene encoding ribosomal RNA in Escherichia coli (Orosz et al. Eur J Biochem. 1991 Nov 1; 201(3): 653-9).

[0074] The control array may be a signal peptide coding sequence that codes for a signal peptide bound to the N-terminus of the polypeptide to be coded and directs the polypeptide into the secretory pathway of the cell, i.e., towards secretion into the extracellular (or periplasmic) space. Any signal peptide coding sequence that directs the expressed polypeptide into the secretory pathway of bacteria may be used. The signal peptide coding sequence can be cleaved by several signal peptidases and removed from the remaining portion of the expressed polypeptide. Examples of effective signal peptide coding sequences for bacterial host cells include, but are not limited to, the signal peptide of Usp45 (SPUsp45), a major Sec-dependent protein secreted by Lactococcus lactis (Borrero et al., 2011. Applied Microbiology and Biotechnology 89(1):131-43), the signal peptide SP310 (Ravn et al. Microbiology (Reading). 2003 Aug;149(Pt 8):2193-2201), and the signal peptide Exp4 (U.S. Patent Application No. US2006199246). It may also be desirable to add regulatory sequences that regulate the expression of the KAT enzyme compared to the growth of the recombinant bacteria. Examples of regulatory systems are those that turn gene expression on or off in response to chemical or physical stimuli, including the presence of regulatory compounds. Regulatory systems in prokaryotic cell lines include the lac, tac, and trp operator systems.

[0075] Typically, the expression cassette comprises, or consists of, a nucleic acid encoding a KAT enzyme operably linked to a transcriptional promoter and a transcriptional terminator. The expression cassette may comprise several nucleic acids encoding several KAT enzymes operably linked to a transcriptional promoter and a transcriptional terminator. Preferably, the expression cassette further comprises a signal peptide coding sequence that results in the secretion of the KAT enzyme into the extracellular space.

[0076] The expression cassette may be used as is to transform bacteria or may be introduced into an expression vector, and the vector may be used to transform bacteria.

[0077] The choice of vector will typically depend on the compatibility of the vector with the bacteria into which it is to be introduced. The vector may be an autonomously replicating vector, i.e., an extrachromosomal entity that exists as such and whose replication is independent of chromosomal replication, such as a plasmid, episome, minichromosome, or artificial chromosome. The vector may contain any means for ensuring self-replication. Alternatively, the vector may be one that, when introduced into bacteria, integrates into the genome and is replicated together with the chromosome into which it has integrated.

[0078] The vector preferably contains one or more selectable markers that enable easy selection of the bacteria containing the vector. Selectable markers are genes whose products confer insecticide or virus resistance, resistance to heavy metals, prototrophy for auxotrophy, and the like. Examples of bacterial selectable markers include, but are not limited to, markers that confer antibiotic resistance such as ampicillin, chloramphenicol, kanamycin, neomycin, spectinomycin, or tetracycline resistance.

[0079] The vector preferably contains factors that enable integration of the vector into the bacterial genome or autonomous replication of the vector in cells independent of the genome. In the case of integration into the host cell genome, integration of the sequence into the genome may depend on homologous or non-homologous recombination. On the one hand, the vector may contain additional polynucleotides for directing integration by homologous recombination at an exact location in the host cell genome. These additional polynucleotides may be any sequence that is homologous to the target sequence in the host cell genome. On the other hand, the vector may be integrated into the host cell genome by non-homologous recombination.

[0080] In autonomous replication, the vector may further include an origin of replication that enables the vector to autonomously replicate in the corresponding bacterium. The origin of replication may be any plasmid replicon that mediates autonomous replication functioning in the cell. The term "origin of replication" or "plasmid replicon" means a polynucleotide that enables a plasmid or vector to replicate in vivo. Examples of origins of replication in bacteria include, but are not limited to, the origins of replication of plasmids pBR322, pUC19, pACYC177, and pACYC184 that enable replication in Escherichia coli (E. coli), and the origins of replication of pUB110, pE194, pTA1060, and pAMβ1 that enable replication in the genus Bacillus.

[0081] Methods for selecting factors according to the bacterium in which expression is desired are well known to those skilled in the art. The vector can be constructed by classical techniques of molecular biology well known to those skilled in the art.

[0082] The recombinant bacterium used in the present invention can be obtained by introducing the expression cassette or vector as described above, so the cassette or vector is maintained as an integrated chromosomal body or as an autonomously replicating extrachromosomal vector. The introduction of the expression cassette or vector into the bacterium can be carried out using any method well known to those skilled in the art. Preferably, at least the expression cassette, or a part thereof containing a nucleic acid encoding the KAT enzyme and enabling the expression of the nucleic acid, is integrated into the genome of the bacterium.

[0083] The recombinant bacteria contained in the composition used in the present invention are live bacteria. This bacterium may be a Live Biotherapeutic Product (LBP), i.e., a living organism designed and developed to treat, cure, or prevent a disease or condition in a subject. By "live bacteria", it should be understood that the integrity of the cells is maintained and that cell processes occur or can occur when the bacteria are cultured in a suitable medium and conditions. Live bacteria can be reseeded in a suitable culture medium and grown under suitable conditions. Live bacteria can be stored prior to administration by freezing in liquid nitrogen, stepwise freezing, or freeze-drying and subsequent storage at a temperature preferably in the range of +4°C to -80°C.

[0084] The recombinant bacteria can be administered to a subject without inducing disease (non-pathogenic bacteria) and can be any bacteria having a metabolism adapted to the gastrointestinal environment. The recombinant bacteria may be genetically engineered to improve their pharmacokinetic and pharmacodynamic properties. For example, the bacteria may be modified to exhibit auxotrophy to limit bacterial replication in the absence of the supplied metabolite. Examples and strategies for developing chassis organisms for engineered live biotherapeutics have recently been reviewed (Charbonneau et al. 2020, Nature Communications volume 11, Article number: 1738), and those skilled in the art can readily select a bacterial chassis suitable for use in the present invention.

[0085] Specifically, the recombinant bacteria belong to the genus Allobaculum (e.g., Allobaculum stercoricanis), the genus Akkermansia (e.g., Akkermansia muciniphila), the genus Anaerostipes (e.g., Anaerostipes hadrus, Anaerostipes caccae, and Anaerostipes butyraticus), the genus Bifidobacterium, the genus Bacillus (e.g., Bacillus subtilis and Bacillus clausii), the genus Propionibacterium, the genus Bacteroides, the genus Eubacterium, the genus Enterococcus, the genus Ruminococcus (e.g., Ruminococcus gnavus), the genus Roseburia (e.g., Roseburia hominis), and the genus Faecalibacterium (e.g., Faecalibacterium prausnitzii), Escherichia coli, and lactic acid bacteria, specifically, the genus Lactobacillus (e.g., Lactobacillus casei, Lactobacillus reuteri, Lactobacillus plantarum, Lactobacillus taiwanensis, Lactobacillus johnsonii, Lactobacillus animalis, Lactobacillus murinus, Lactobacillus salivarius, Lactobacillus gasseri, Lactobacillus bulgaricus, LactobacillusIt can be selected from the group consisting of lactic acid bacteria belonging to Lactobacillus delbrueckii subsp. bulgaricus, Lactococcus spp. (e.g., Lactococcus lactis), and Streptococcus spp. (e.g., Streptococcus thermophilus). Preferably, the recombinant bacterium is selected from the group consisting of bacteria belonging to the genera Lactobacillus and Lactococcus, specifically Lactobacillus casei and Lactococcus lactis.

[0086] In some other embodiments, the composition used in the present invention comprises xanthurenic acid, its derivatives, or any pharmaceutically acceptable salts or solvates thereof.

[0087] In one embodiment, the xanthurenic acid derivative is of formula (I)

[0088] [Chemical formula]

[0089] [Wherein, R1, R2, and R3 are a hydrogen atom, a hydroxyl group, a halogen atom, a -CO-R8 group or a -CO2R8 group (R8 is H or C 1~10 is an alkyl group), -NR9R 9' (R9 and R 9' are independently a hydrogen atom or C 1~10 is an alkyl group), a nitro group, a cyano group, C optionally substituted by a halogen atom 1~10 alkyl, C 2~10 alkenyl or C 2~10 alkynyl group, and C optionally substituted by a halogen atom 1~10 alkyloxy, and are independently selected from the group consisting of; R4 and R6 are independently selected from the group consisting of a hydrogen atom and C 1~10 alkyl group; R5 is a hydroxyl group, a hydrogen atom, -NR7R 7' (wherein R7 and R 7' are each independently a hydrogen atom or a C 1~10 alkyl group), a C 1~10 alkyl group, and a C 1~10 alkoxy group selected from the group consisting of] or a tautomeric form thereof.

[0090] In a specific embodiment, the xanthurenic acid derivative is wherein R1, R2 and R3 are each independently selected from the group consisting of a hydrogen atom, a hydroxyl group, a halogen atom, a C 1~10 alkyl optionally substituted by a halogen atom, a C 2~10 alkenyl or a C 2~10 alkynyl group; R4 and R6 are each independently selected from the group consisting of a hydrogen atom and a C 1~10 alkyl group; R5 is a hydroxyl group, -NR7R 7' (wherein R7 and R 7' are each independently a hydrogen atom or a C 1~10 alkyl group), a C 1~10 alkyl group, and a C 1~10 alkoxy group selected from the group consisting of, of formula (I) or a tautomeric form thereof.

[0091] In another specific embodiment, the xanthurenic acid derivative is wherein R1, R2 and R3 are each independently selected from the group consisting of a hydrogen atom, a hydroxyl group, a halogen atom, a C 1~6 alkyl optionally substituted by a halogen atom, a C 2~6 alkenyl or a C 2~6 alkynyl group; R4 and R6 are each independently selected from the group consisting of a hydrogen atom and a C 1~6 alkyl group; R5 is a hydroxyl group, -NR7R 7' (wherein R7 and R 7' are each independently a hydrogen atom or a C 1~6 alkyl group), a C 1~6An alkyl group, and C 1~6 selected from the group consisting of an alkoxy group, is of formula (I) or a tautomeric form thereof.

[0092] In another specific embodiment, the xanthurenic acid derivative is R1, R2 and R3 are independently selected from the group consisting of a hydrogen atom, an oxygen atom, a halogen atom, and a C 1~10 alkyl, C 2~10 alkenyl or C 2~10 alkynyl group; R4 and R6 are independently selected from the group consisting of a hydrogen atom and a C 1~10 alkyl group, or R4 and / or R6 are absent; R5 is selected from the group consisting of a hydroxyl group, NHR7, NR7R7, and C 1~10 alkyl or alkoxy group (wherein R7 is selected from the group consisting of a hydrogen atom and a C 1~10 alkyl group), is of formula (I).

[0093] In another specific embodiment, the xanthurenic acid derivative is R1, R2 and R3 are independently selected from the group consisting of a hydrogen atom, an oxygen atom, a halogen atom, and a C 1~6 alkyl, C 2~6 alkenyl or C 2~6 alkynyl group; R4 and R6 are independently selected from the group consisting of a hydrogen atom and a C 1~6 alkyl group, or R4 and / or R6 are absent; R5 is selected from the group consisting of a hydroxyl group, NHR7, NR7R7, and C 1~6 alkyl or alkoxy group (R7 is selected from the group consisting of a hydrogen atom and a C 1~6 alkyl group), is of formula (I).

[0094] For example, C1-C 10, C1 - C6 or C2 - C 10 Terms described herein with prefixes such as etc. can also be used with a smaller number of carbon atoms, such as C1 - C9, C1 - C5, or C2 - C9, etc. For example, if the term C1 - C 10 is used, this means that the corresponding hydrocarbon chain may contain 1 - 10 carbon atoms, particularly 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 carbon atoms. For example, if the term C1 - C6 is used, this means that the corresponding hydrocarbon chain may contain 1 - 6 carbon atoms, particularly 1, 2, 3, 4, 5, or 6 carbon atoms. For example, if the term C2 - C6 is used, this means that the corresponding hydrocarbon chain may contain 2 - 6 carbon atoms, particularly 2, 3, 4, 5, or 6 carbon atoms.

[0095] As used herein, the term "alkyl" refers to a monovalent radical containing only carbon and hydrogen atoms arranged in a straight or branched chain. (C1 - C3)-alkyl groups include methyl, ethyl, propyl, or isopropyl. Preferably, the (C1 - C3)-alkyl group is methyl or ethyl, more preferably methyl. (C1 - C6)-alkyl groups include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, or hexyl.

[0096] As used herein, the term "alkenyl" refers to an unsaturated straight or branched aliphatic group containing at least one carbon-carbon double bond. The term "(C2 - C6) alkenyl" more specifically means ethenyl, propenyl, isopropenyl, butenyl, isobutenyl, pentenyl, or hexenyl.

[0097] The term "alkynyl" refers to an unsaturated straight or branched aliphatic group containing at least one carbon-carbon triple bond. The term "(C2 - C6) alkynyl" more specifically means ethynyl, propynyl, butynyl, pentynyl, isopentynyl, or hexynyl.

[0098] The term "halogen" corresponds to a fluorine, chlorine, bromine, or iodine atom.

[0099] Examples of xanthurenic acid derivatives include, but are not limited to, oxo-xanthurenic acid (OXA) and di-oxo-xanthurenic acid (DOXA).

[0100] [Table 5]

[0101] In a preferred embodiment, the composition comprises xanthurenic acid or any pharmaceutically acceptable salt or solvate thereof.

[0102] Xanthurenic acid is of the formula (II)

[0103] [Chemical formula]

[0104] as follows.

[0105] Certain compounds described in this disclosure may exist in tautomeric forms, and it will be apparent to those skilled in the art that all such tautomeric forms of the compounds are within the scope of this disclosure. Specifically, the term "xanthurenic acid" includes the compound of formula (II) and its tautomeric forms, for example, the compounds of formulas (III) and (IV).

[0106] [Chemical formula]

[0107] The pharmaceutically acceptable salts of xanthurenic acid or its derivatives are salts that are non-toxic to patients and are suitable for maintaining the stability of the said compounds and enabling the delivery of the said compounds to target cells or tissues. Pharmaceutically acceptable salts are well-known in the art. More specifically, "pharmaceutical salts" include inorganic and further organic acid salts. Representative examples of suitable inorganic acids include hydrochloric acid, hydrobromic acid, hydroiodic acid, phosphoric acid, and the like. Representative examples of suitable organic acids include formic acid, acetic acid, trichloroacetic acid, trifluoroacetic acid, propionic acid, benzoic acid, cinnamic acid, citric acid, fumaric acid, maleic acid, methanesulfonic acid, and the like. Further examples of pharmaceutically acceptable inorganic or organic acid addition salts include the pharmaceutical salts listed in J. Pharm. Sci. 1977, 66, 2 and Handbook of Pharmaceutical Salts: Properties, Selection, and Use, edited by P. Heinrich Stahl and Camille G. Wermuth 2002. "Pharmaceutical salts" also include inorganic and further organic base salts. Representative examples of suitable inorganic bases include sodium or potassium salts, alkaline earth metal salts, such as calcium or magnesium salts, or ammonium salts. Representative examples of suitable salts with organic bases include salts with, for example, methylamine, dimethylamine, trimethylamine, piperidine, morpholine, or tris-(2-hydroxyethyl)amine.

[0108] As used herein, the term "solvate" refers to a solvate form containing a stoichiometric or non-stoichiometric amount of a solvent. Some compounds have a tendency to form solvates by trapping a molar ratio of solvent molecules in the crystalline solid state. If the solvent is water, the solvate formed is a hydrate. When the solvent is alcohol, the solvate formed is an alcoholate. Hydrates are formed by the combination of one or more water molecules with one of the substances in which water retains its molecular state as H2O, and such combinations can form one or more hydrates.

[0109] The composition used in the present invention may be a pharmaceutical composition, a food composition or a food supplement.

[0110] In embodiments where the composition is a pharmaceutical composition, an active compound as defined above, namely kynurenine aminotransferase, a live recombinant bacterium genetically modified to express and secrete said kynurenine aminotransferase, and / or xanthurenic acid or a derivative thereof, or any pharmaceutically acceptable salt or solvate thereof, in combination with pharmaceutically acceptable additives, and optionally a sustained release matrix such as a biodegradable polymer, can form a therapeutic composition.

[0111] "Pharmaceutically" or "pharmaceutically acceptable" refers to molecular entities and compositions that do not produce adverse allergic or other harmful reactions when appropriately administered to mammals, particularly humans. A pharmaceutically acceptable carrier or additive refers to any kind of non-toxic solid, semi-solid or liquid diluent, excipient, encapsulating material or formulation auxiliary. Pharmaceutically acceptable additives that can be used in the compositions according to the present invention are well known to those skilled in the art and may vary depending on the disease being treated and the route of administration.

[0112] The composition can be administered by enteral or parenteral routes, preferably by oral, sublingual, subcutaneous, intramuscular, intravenous, transdermal, topical or rectal routes of administration. Preferably, the composition is administered or adapted for administration by rectal or oral routes.

[0113] Specifically, in some embodiments where the composition comprises kynurenine aminotransferase and / or xanthurenic acid or a derivative thereof, the composition is preferably administered by oral, rectal, subcutaneous or intravenous routes. In some other embodiments where the composition comprises live recombinant bacteria, the composition is preferably administered by oral or rectal routes.

[0114] In one embodiment, the pharmaceutical composition can be administered via the oral route. For oral administration, the pharmaceutical composition can be formulated into conventional oral dosage forms such as tablets, capsules, powders, granules, and liquid preparations such as syrups, elixirs, and concentrated drops. For example, non-toxic solid carriers or diluents containing pharmaceutical-grade mannitol, lactose, starch, magnesium stearate, sodium saccharin, talc, cellulose, glucose, sucrose, magnesium, carbonate, and the like may be used. For compressed tablets, a binder, which is a drug that imparts cohesiveness to the powdered substance, is also required. For example, starches, gelatin, sugars such as lactose or dextrose, and natural or synthetic rubbers can be used as binders. To facilitate the disintegration of the tablets, a disintegrant may also be required in the tablets. Disintegrants include starches, clays, celluloses, algins, gums, and cross-linked polymers. Further, lubricants and flow promoters may be included in the tablets to prevent the adhesion of tablet substances to the surface during the manufacturing process and to improve the flow characteristics of the powdered substances during manufacturing. Colloidal silicon dioxide is most commonly used as a flow promoter, and compounds such as talc or stearic acid are most commonly used as lubricants. Well-known thickeners such as corn starch, agar, natural or synthetic rubbers, resins, methylcellulose, sodium carboxymethylcellulose, guar, xanthan, and the like may be added to the composition. Preservatives containing methylparaben, propylparaben, benzyl alcohol, and ethylenediaminetetraacetate may be included in the composition.

[0115] Preferably, for oral administration, the composition is in a gastric-resistant oral form that allows the active compound contained in the composition to pass through the stomach and be released into the small intestine. Substances that can be used in enteric coatings include, for example, alginic acid, cellulose acetate phthalate, plastics, waxes, shellac, and fatty acids (e.g., stearic acid or palmitic acid).

[0116] In another embodiment, the pharmaceutical composition can be administered by the rectal route. Suitable rectal route forms include, but are not limited to, suppositories and enemas. Specifically, the active compound can be introduced into any of the known suppository bases by methods known in the art. Examples of such bases include cocoa butter, polyethylene glycol (Carbowax), polyethylene sorbitan monostearate, and mixtures thereof with other compatible substances for adjusting the melting point or dissolution rate.

[0117] The compositions used in the present invention can be formulated to release the active compound substantially immediately upon administration, or at any predetermined time or period after administration.

[0118] The pharmaceutical compositions used in the present invention can also be used in combination with, or further contain, at least one additional active ingredient, specifically, at least one bacterial probiotic and / or at least one prebiotic and / or at least one drug useful in the treatment of arthritis diseases.

[0119] The term "bacterial probiotics" has its common meaning in the art and refers to useful bacteria that can bring about beneficial effects on the health of the host, i.e., are applicable to the prevention, treatment, or cure of diseases or conditions of the host, preferably a human. This term can refer to dead or live bacteria. Preferably, this term refers to live bacteria (also named live biological agents). Preferably, the bacterial probiotics exhibit anti-inflammatory activity. Such bacterial probiotics can be selected from the group consisting of bacteria belonging to, for example, the genus Allobaculum (e.g., Allobaculum stercorianis), the genus Akkermansia (e.g., Akkermansia muciniphila), the genus Anaerostipes (e.g., Anaerostipes hadrus, Anaerostipes caccae, and Anaerostipes butyraticus), the genus Bifidobacterium, the genus Bacillus (e.g., Bacillus subtilis and Bacillus clausii), the genus Propionibacterium, the genus Bacteroides, the genus Eubacterium, the genus Enterococcus, the genus Lachnococcus (e.g., Lachnococcus gnavus), the genus Roseburia (e.g., Roseburia hominis), and the genus Faecalibacterium (e.g., Faecalibacterium prausnitzii), Escherichia coli, and lactic acid bacteria, specifically, lactic acid bacteria belonging to the genus Lactobacillus (e.g., Lactobacillus reuteri, Lactobacillus plantarum, Lactobacillus taiwanensis, Lactobacillus johnsonii, Lactobacillus animalis, Lactobacillus murinus, Lactobacillus salivarius, Lactobacillus gasseri, Lactobacillus bulgaricus, and Lactobacillus delbrueckii subsp. bulgaricus), the genus Lactococcus, and the genus Streptococcus (e.g., Streptococcus thermophilus).

[0120] As used herein, "prebiotics" refers to components that can induce specific changes in both the administered probiotics and / or the composition and / or activity of the gastrointestinal microbiota, and can bring benefits to the host. Preferably, the prebiotics can be decomposed by probiotics and can increase the shelf life of the probiotics after administration to the patient. Examples of prebiotics include, but are not limited to, complex carbohydrates, polyphenols, amino acids, peptides, minerals, or other nutritional components that are essential for the survival of probiotics. Specifically, the prebiotics can be selected from the group consisting of inulin, inositol, tagatose, lactulose, alpha-glucan oligosaccharides, trans-galacto-oligosaccharides (TOS), fructo-oligosaccharides (FOS), galacto-oligosaccharides (GOS), xylo-oligosaccharides (XOS), and mixtures thereof.

[0121] Examples of drugs useful in the treatment of arthritis diseases include, but are not limited to, immunosuppressive drugs such as azathioprine, methotrexate, leflunomide, hydroxychloroquine, sulfasalazine, anti-TNF drugs (infliximab, adalimumab, golimumab, certolizumab, etc.), rituximab, JAK inhibitors (tofacitinib, etc.), analgesics, non-steroidal anti-inflammatory drugs such as ibuprofen, naproxen or diclofenac, and steroids such as prednisolone.

[0122] In a preferred embodiment, the composition does not contain quinolinic acid.

[0123] In other embodiments, the composition may be a food composition or a food supplement.

[0124] "Food composition" means any composition containing food ingredients such as macronutrients, micronutrients, vitamins and / or minerals. The food composition may be intended for human or animal consumption and may be in liquid, paste or solid form. Examples of food compositions include, but are not limited to, dairy products such as cheese, butter, cream, yogurt, fermented milk, ice cream, etc., cooked products such as bread, biscuits and cakes, fruit products such as fruit juice, fruit compote or fruit paste, soy food products, starch-based food products, edible oil compositions, spreads, breakfast cereals, prepared milk powder for infants, food bars (e.g., cereal bars, breakfast bars, energy bars, nutritional bars), chewing gum, beverages, drink supplements (powders added to beverages).

[0125] As used herein, the term "food supplement" refers to any composition that is formulated and administered separately from other foods to supplement the nutrition of a subject, i.e., a human or an animal. This supplement may be in any suitable form known to those skilled in the art, preferably in the form of a dietary food or an oral supplement.

[0126] In certain embodiments, the pharmaceutical composition, food composition or food supplement may further comprise nicotinamide adenine dinucleotide (NAD), or a precursor thereof, or may be used in combination with NAD, or a precursor thereof. NAD may be administered in its oxidized (NAD+) or reduced (NADH) form. Examples of NAD precursors include, but are not limited to, nicotinamide (NAM), nicotinic acid (NA), nicotinamide mononucleotide (NMN), and nicotinamide riboside (NR).

[0127] Preferably, in these embodiments, the pharmaceutical composition, food composition or food supplement comprises a KAT enzyme.

[0128] Preferably, the nicotinamide adenine dinucleotide or its precursor is administered via the oral or intravenous route. Depending on the nature of the composition and the route of administration, the nicotinamide adenine dinucleotide or its precursor and the composition can be administered simultaneously, or separately, via the same route or via different routes.

[0129] The composition as described above is used in the treatment of arthritis diseases. The present invention also relates to the use of the composition as described above for the manufacture of a medicament for treating arthritis diseases. The present invention further relates to a method for treating arthritis diseases in a subject, the method comprising administering the composition as described above to the subject.

[0130] As used herein, the terms "treatment", "treating" or "treatment" refer to any act intended to improve the health status of a patient, such as the treatment, prevention, prophylaxis and delay of a disease. In certain embodiments, such terms refer to the improvement or eradication of a disease or symptoms associated therewith. In other embodiments, the term refers to the minimization of the spread or exacerbation of such diseases resulting from the administration of one or more therapeutic agents, such as the compositions of the present invention, to a subject having the disease.

[0131] As used herein, the term "arthritis" or "arthritis disease" refers to any particular disease characterized by a chronic inflammatory condition that primarily affects the joints or the connective tissues surrounding the joints, although various body organs can also be affected. The etiology of the inflammation can vary under various conditions. In particular, arthritis can originally be autoimmune or traumatic, or can be caused by exposure to foreign antigens.

[0132] Examples of arthritis diseases include, but are not limited to, rheumatoid arthritis, juvenile idiopathic arthritis, ankylosing spondylitis, cervical spondylosis, gout, psoriatic arthritis, inflammatory bowel disease arthritis, Lyme disease arthritis, septic arthritis, reactive arthritis.

[0133] The arthritis disease is preferably selected from the group consisting of rheumatoid arthritis, juvenile idiopathic arthritis, gout, psoriatic arthritis, inflammatory bowel disease arthritis, Lyme disease arthritis, septic arthritis, and reactive arthritis.

[0134] More preferably, the arthritis disease is rheumatoid arthritis.

[0135] The subject to be treated with the composition of the present invention is an animal, preferably a mammal. In one embodiment, the subject is a household or breeding animal such as a dog, cat, cow, sheep, horse or rodent. In a preferred embodiment, the subject is a human including adults, children, newborns and pre-birth stage humans. As used herein, the terms "subject", "individual" and "patient" are interchangeable.

[0136] The dosage of the active compound as defined above, i.e., kynurenine aminotransferase, a live recombinant bacterium genetically modified to express and secrete said kynurenine aminotransferase, and / or xanthurenic acid or a derivative thereof, or any pharmaceutically acceptable salt or solvate thereof, can be appropriately adjusted according to criteria such as age, symptoms, weight, and intended use so that a therapeutically effective amount is obtained. As used herein, the term "therapeutically effective amount" refers to the amount necessary to obtain an advantageous effect on the disease being treated, i.e., to prevent, eliminate, or reduce at least one adverse effect of the disease. The therapeutically effective amount is preferably defined as the amount necessary to have an impact on the arthritis disease or any symptom of the disease, for example, to reduce pain, reduce joint swelling, slow down or prevent permanent damage to joints and other tissues, or improve joint function or flexibility.

[0137] In some embodiments, the composition may contain 10 3 ~10 11 live recombinant bacterial cells as defined above per 1 mg of the composition. Specifically, the amount of live recombinant bacterial cells as defined above ingested per day is 1×106 ~1×10 11 CFU / body, preferably 0.1×10 9 ~10×10 9 CFU / body, more preferably 0.3×10 9 ~5×10 9 It may be ~5×10 cells / body. The content rate of viable recombinant bacterial cells as defined above contained in the composition of the present invention to be orally ingested may be, for example, 1% to 100% (w / w, that is, bacterial dry mass / total dry mass of the composition), preferably 1% to 75% (w / w), and more preferably 5% to 50% (w / w).

[0138] In some other embodiments, the composition may contain 0.001 mg to 1 mg of the KAT enzyme as defined above per 1 mg of the composition. Specifically, the amount of the KAT enzyme as defined above ingested per day may be 0.001 mg / body to 100 mg / body. The content rate of the KAT enzyme as defined above contained in the composition of the present invention to be orally ingested may be, for example, 0.1% to 100% (w / w, that is, KAT enzyme mass / total dry mass of the composition), preferably 0.1% to 75% (w / w).

[0139] In some other embodiments, the composition may contain 0.001 mg to 1 mg of xanthurenic acid or its derivative as defined above per 1 mg of the composition. Specifically, the amount of xanthurenic acid or its derivative as defined above ingested per day may be 0.001 mg / body to 100 mg / body. The content rate of xanthurenic acid or its derivative as defined above contained in the composition of the present invention to be orally ingested may be, for example, 0.1% to 100% (w / w, that is, xanthurenic acid or derivative mass / total dry mass of the composition), preferably 0.1% to 75% (w / w), more preferably 0.5% to 50% (w / w).

[0140] The composition of the present invention can be administered as a single dose or in multiple doses. Specifically, depending on the age or physiological condition of the subject, the daily dose can be divided, for example, into one administration in the morning and another administration in the evening to facilitate administration.

[0141] In some embodiments, the composition can be administered regularly, preferably between daily and monthly, more preferably between daily and every two weeks, and even more preferably between daily and weekly. In some specific embodiments, the composition can be administered daily.

[0142] The duration of treatment with the composition of the present invention may be included between one day and several years, preferably between one day and one year, and more preferably between one day and six months.

[0143] All the reference documents cited herein are incorporated herein by reference. Other features and advantages of the present invention will become apparent in the following examples, which are presented for illustrative purposes and not intended to be limiting.

Examples

[0144] (Example 1) Materials and Methods Collagen antibody-induced arthritis model Male C57BL6J mice were intraperitoneally injected with a cocktail of arthritis-inducing anti-type II collagen (2 mg / mouse) on day 0. On day 3, the mice were administered an injection of lipopolysaccharide from the bacterial cell wall of Escherichia coli 055:B5. The severity of arthritis was evaluated every other day with a score of 0 - 4 for each paw and a maximum score of 16 per animal (0 = normal joint, 1 = moderate erythema of 1 or 2 digits and slight swelling or edema, 2 = moderate erythema and moderate paw swelling or swelling of more than 3 digits, 3 = erythema and swelling from the ankle joint to the midfoot joint, 4 = severe erythema and severe swelling of the entire paw). Hind paw swelling was simultaneously measured with a plethysmograph. The paw volume determined before disease induction was used as the baseline. The development of arthritis was analyzed by histological evaluation. The hind paws were dissected and then fixed in 4% formalin (Labonord). The hind paws were further decalcified in 10% EDTA for 1 month and embedded in paraffin blocks. Tissue sections 5 μm thick were cut and two stains were performed with hematoxylin, eosin, and toluidine blue. Histological examinations were performed blindly by three independent observers. The synovium from the ankle joint was graded on a scale of 0 - 3 (0 = normal, and 3 = large changes) for synovial hyperplasia (inner layer thickness) and tissue cell infiltration. Cartilage degradation was graded from 0 = fully stained cartilage, 1 = de-stained cartilage, 2 = de-stained cartilage with synovial cell infiltration, 3 = complete loss of cartilage. The following morphological criteria were used for osteopenia: 0 = normal, 1 = slight loss of cortical bone at a few sites, 2 = moderate loss of cortical and trabecular bone, and 3 = marked loss of bone at many sites.

[0145] Cloning of Mouse Alpha-Aminoadipate Aminotransferase (AADAT) in Escherichia coli Codon usage of a gene synthesized by GeneArt encoding murine AADAT (muAADAT, SEQ ID NO: 13) (pMA:muAADAT plasmid). Subsequently, the DNA fragment encoding muAADAT was recovered after digestion with NheI and XhoI restriction enzymes and cloned into the pStaby 1 vector (Delphi Genetics) previously digested with the same enzymes. The use of the pStaby 1 plasmid (Figure 3A) allows for the introduction of a C-terminal 6-histidine tag (His-tag) that enables subsequent purification of muAADAT under the control of the phage T7 RNA polymerase promoter (T7 polymerase) using affinity chromatography. The final vector pStaby:muAADAT (Figure 3B) was transferred into T7 Express Competent E. coli (NEB), and the transformants were grown overnight (ON) at 37 °C with shaking at 180 rpm in 10 mL of Luria-Bertani medium containing ampicillin (Amp, 100 μg / mL). Plasmid DNA was extracted from the positive clones and sequenced to confirm their identity.

[0146] Method for quantitative targeted metabolomics of tryptophan metabolites in serum The sample was lyophilized (3 mg) and weighed. Quantitative analysis of tryptophan metabolites was performed as previously described (Lefevre et al., Talanta 195 (2019) 593 - 598). 5 μL was injected into an LC-MS (XEVO-TQ-XS, Waters®). A Kinetex C18 xb column (1.7 μm × 150 mm × 2.1 mm, temperature 55 °C) with a gradient of two mobile phases (phase A: water + 0.5% formic acid; phase B: MeOH + 0.5% formic acid) at a flow rate of 0.4 mL / min was used.

[0147] For each metabolite, a calibration curve was created by calculating the intensity ratio obtained between the metabolite and its internal standard. These calibration curves were then used to determine the concentration of each metabolite in the patient samples.

[0148] Expression and Purification of Recombinant Mouse AADAT Protein in Escherichia coli The E. coli strain expressing muAADAT was cultured at 37°C overnight with shaking at 180 rpm in 100 mL of LB supplemented with 100 μg / mL of ampicillin, and then cultured in 10 L of LB with 100 μg / mL of ampicillin at 37°C. When an optical density (OD600nm) of 0.8 - 1.0 was achieved, gene expression was induced by adding 0.25 mM IPTG, and the culture was incubated at 16°C overnight with stirring at 180 rpm (Figure 3C). The bacteria were harvested by centrifugation, the cell pellet was washed with PBS, and resuspended in 100 ml of Binding Buffer (PBS buffer supplemented with 0.1% 10X Triton and 1X protease inhibitor, pH 7.4 - 300 mM NaCl, Rock). The cells were then sonicated in ice at 40% amplitude for 5 seconds, then stopped for 3 seconds for 20 minutes. The lysate was then centrifuged at 15,000 g for 30 minutes at 4°C to separate the soluble fraction from the cell pellet. The soluble fraction containing AADAT was purified by affinity chromatography. 100 mL of the supernatant was incubated with 4 mL of Ni-NTA agarose resin (ref. R901-15 from Invitrogen) at 4°C for 1 hour and then loaded onto a BioRad column. The AADAT protein immobilized on the resin was washed with 100 mL of PBS buffer pH 7.4 - 500 mM NaCl, then 25 mL of PBS buffer pH 7.4 - 300 mM NaCl - 20 mM imidazole and 10 mL of buffer. PBS buffer pH 7.4 - 300 mM NaCl - 40 mM imidazole. The AADAT protein was eluted with 8 ml of PBS buffer pH 7.4 - 300 mM NaCl - 300 mM imidazole (Figure 3D). Fractions 2 - 6 were pooled and dialyzed against 1 L of PBS, 50% glycerol - 300 mM NaCl Specta / Port6. The protein was stored at -20°C. A precast BioRad Mini-PROTEAN TGX stain-free, 4 - 20% gel was run to monitor the different stages of purification.

[0149] Verification of AADAT Activity Assay The activity assay is based on the disappearance of kynurenine and 3-hydroxykynurenine, which are substrates of AADAT. A reaction mixture (final volume 50 μL) containing 10 mM L-kynurenine or 3-hydroxykynurenine, 2 mM α-oxoglutarate, 40 μM PLP (pyridoxal 5'-phosphate), and 0 or 1 μL of purified protein sample prepared in 100 mM potassium phosphate buffer (pH 7.4). The mixture was then incubated at 37 °C for 15 minutes, and the reaction was stopped by the addition of an equal volume of 30% acetic acid. The supernatant of the reaction mixture obtained by centrifugation at 3000 g for 10 minutes at 4 °C was mixed with an equal volume of Ehrlich's reagent and incubated at room temperature for 15 minutes to obtain a colorimetric reaction. In parallel, a standard range of 0 μM to 1000 μM of kynurenine or 3-hydroxykynurenine was prepared under the same conditions. The amount of kynurenine or 3-hydroxykynurenine present in the sample was measured spectrophotometrically at an OD of 492 nm and calculated using the standard range (Figure 3E). Verification of the production of KYNA and XANA in vitro over 15 minutes in the presence of KYNU (1000 μM) by the action of our enzyme was performed (Figure 3F). The dose effect can be observed from the conversion of KYNU to KYNA and XANA.

[0150] Measurement of AADAT levels in the sera of patients with RA AADAT was quantified by ELISA according to the manufacturer's instructions (XpressBio, XPEH1430).

[0151] Statistical analysis Data were analyzed using Prism version 7 (Graphpad Software, San Diego, USA). Non-parametric Mann-Whitney tests or parametric one-way ANOVA tests were performed together with multiple Bonferroni comparison tests. Values are expressed as mean ± SEM. Statistical significance was defined as a p-value **** <0.0001, *** <0.001, ** <0.01, * <0.05.

[0152] Results Tryptophan metabolism is divided into three pathways: the indole, serotonin, and kynurenine pathways. The metabolites that make up the kynurenine pathway are tryptophan, kynurenine (KYNU), kynurenic acid (KYNA), 3-hydroxykynurenine (3HK), xanthurenic acid (XANA), 3-hydroxyanthranilic acid (3-HAA), picolinic acid, and quinolinic acid (Figure 1). Here, this pathway was investigated in rheumatoid arthritis (RA).

[0153] First, the inventors analyzed tryptophan metabolism in 574 treatment-naive patients with RA (ESPOIR cohort) and 98 healthy subjects by targeted quantitative metabolomics in serum. The inventors observed several differences between RA patients and healthy subjects, particularly a decrease in kynurenic acid (KYNA) and the xanthurenic acid (XANA) / 3-hydroxykynurenine (3H-Kyn) ratio, and an increase in quinolinic acid (QUIN) and the QUIN / 3 anthranilic acid (3HAA) ratio (Figure 1).

[0154] The inventors observed a negative correlation between several markers of disease activity (disease activity score-28, C-reactive protein) and pro-inflammatory cytokines (TNFa, IL6, MCP1, IL1RA, etc.) and KYNA and XANA (furthermore, the ratios between KYNA, XANA, and their precursors and kynurenine and 3-hydroxykynurenine, respectively). The opposite was observed for kynurenine and QUIN (data not shown). Similar correlations were observed for quality of life scores such as the SF36 score, MHI5 (Mental Health Inventory5), EQ5D (a standardized measure of health-related quality of life developed by the EuroQol Group).

[0155] Next, the inventors measured AADAT levels (ELISA, XpressBio, XPEH1430 according to the manufacturer's instructions) in the serum of patients with RA and observed a dramatic decrease compared to healthy subjects (Figure 2).

[0156] Based on these results, the inventors hypothesized that modifying changes in tryptophan metabolism might have a therapeutic effect in RA. The inventors have clearly identified the enzyme kynurenine aminotransferase, also known as AADAT (aminoadipic acid aminotransferase), as a promising therapeutic agent that is beneficial for the production of XANA and KYNA but decreases the production of QUIN.

[0157] AADAT was produced and purified and then intraperitoneally administered to mice during a collagen antibody-induced arthritis model. Male C57BL6J mice were intraperitoneally injected with an arthritis-inducing cocktail of anti-type II collagen on day 0. On day 3, the mice were administered an injection of lipopolysaccharide from the bacterial cell wall of Escherichia coli 055:B5. The mice were intraperitoneally administered recombinant AADAT (about 50 μg / d) daily. This experiment was reproduced twice with 8 mice per group (AADAT treatment or vehicle treatment). Treatment with AADAT dramatically reduced arthritis severity (the average maximum clinical score decreased from 6.9 to 2.6), which was confirmed by measurement of edema swelling and histology (Figure 4).

[0158] In conclusion, these results indicate strong therapeutic potential for the administration of recombinant enzyme AADAT in RA.

Claims

1. A composition for use in the treatment of arthritis, - Kynurenine aminotransferase (KAT), and / or - Live recombinant bacteria genetically modified to express and secrete the kynurenine aminotransferase, and / or - Products of kynurenine aminotransferase, which are xanthurenic acid, its derivatives, or any pharmaceutically acceptable salt or solvate thereof. A composition containing the following:

2. The composition according to claim 1, wherein the arthritis disease is selected from the group consisting of rheumatoid arthritis, juvenile idiopathic arthritis, ankylosing spondylitis, cervical spondylosis, gout, psoriatic arthritis, enteritis arthritis, Lyme disease arthritis, septic arthritis, and reactive arthritis, and preferably selected from the group consisting of rheumatoid arthritis, juvenile idiopathic arthritis, gout, psoriatic arthritis, enteritis arthritis, Lyme disease arthritis, septic arthritis, and reactive arthritis.

3. The composition according to claim 1, wherein the arthritis disease is rheumatoid arthritis.

4. The composition according to claim 1, wherein the kynurenine aminotransferase is selected from the group consisting of human kynurenine / alpha-aminoadipate aminotransferase (KAT II), human kynurenine-oxoglutarate transaminase 1 (KAT I), human kynurenine-oxoglutarate transaminase 3 (KAT III), human mitochondrial aspartate aminotransferase (KAT IV), its orthologs, and its variants, wherein the variant has at least 80% sequence identity with respect to human KAT I, human KAT II, ​​human KAT III, human KAT IV, or any of its orthologs, and exhibits kynurenine aminotransferase activity.

5. The composition according to claim 1, wherein the kynurenine aminotransferase is selected from the group consisting of human KAT II, ​​human KAT III, human KAT IV, their orthologs, and their variants, and the variant has at least 80% sequence identity with respect to human KAT II, ​​human KAT III, human KAT IV, or any of their orthologs, and exhibits kynurenine aminotransferase activity.

6. The composition according to claim 1, wherein the kynurenine aminotransferase is selected from the group consisting of human KAT II, ​​its ortholog, and its variant, and the variant has at least 80% sequence identity with respect to human KAT II or any ortholog thereof, and exhibits kynurenine aminotransferase activity.

7. The composition according to claim 1, wherein the kynurenine aminotransferase is selected from the group consisting of the KAT protein of SEQ ID NOs. 1 to 32 and variants thereof that have at least 80% sequence identity with any sequence of SEQ ID NOs. 1 to 32 and exhibit kynurenine aminotransferase activity.

8. The composition according to claim 1, wherein the kynurenine aminotransferase is selected from the group consisting of the KAT protein of SEQ ID NOs. 10 to 16 and variants thereof that have at least 80% sequence identity with any sequence of SEQ ID NOs. 10 to 16 and exhibit kynurenine aminotransferase activity.

9. The composition according to claim 1, comprising the kynurenine aminotransferase.

10. The composition according to claim 1, comprising a recombinant bacterium genetically modified to express and secrete the kynurenine aminotransferase.

11. The composition according to claim 1, wherein the recombinant bacteria are selected from the group consisting of bacteria belonging to the genera Allobaculum, Adrecruzia, Anaerostipes, Bifidobacterium, Propionibacterium, Bacteroid, Eubacterium, Enterococcus, Ruminococcus, and Faecalibacterium, Escherichia coli, and lactic acid bacteria such as bacteria belonging to the genera Lactobacillus, Lactococcus, and Streptococcus.

12. A compound comprising xanthurenic acid, its derivatives, or any pharmaceutically acceptable salt or solvate thereof, wherein the xanthurenic acid derivative is of formula (I). 【Chemistry 1】 [In the formula, R 1 , R 2 and R 3 are each independently a hydrogen atom, a hydroxyl group, a halogen atom, a -CO-R 8 group or a -CO 2 R 8 (where R 8 is H or a C 1～10 alkyl group), a -NR 9 R 9' (where R 9 and R 9' are each independently a hydrogen atom or a C 1～10 alkyl group), a nitro group, a cyano group, a C 1～10 alkyl, C 2～10 alkenyl or C 2～10 alkynyl group, and a C 1～10 alkyloxy optionally substituted by a halogen atom, and are independently selected from the group consisting of; R 4 and R 6 is a hydrogen atom, and C 1～10 Independently selected from the group consisting of alkyl groups; R 5 This consists of a hydroxyl group, a hydrogen atom, and -NR 7 R 7' (R 7 and R 7' These are independently hydrogen atoms or C 1～10 C 1～10 Alkyl alkyl groups, and C 1～10 Selected from the group consisting of alkoxy groups] The composition according to claim 1, or a tautomer thereof.

13. The composition according to claim 1, wherein the xanthurenic acid derivative is selected from the group consisting of oxo-xanthurenic acid (OXA) and dioxo-xanthurenic acid (DOXA).

14. The composition according to claim 1, comprising xanthurenic acid or any pharmaceutically acceptable salt or solvate thereof.

15. The composition according to claim 1, further comprising nicotinamide adenine dinucleotide or its precursor, or used in combination with nicotinamide adenine dinucleotide or its precursor.

16. Use of the composition according to any one of claims 1 to 15 for manufacturing a medicament for treating arthritis.

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