Application of Ptprj agonist GJ103 in preparation of medicine for treating cisplatin-induced acute kidney injury

Abstract

The invention belongs to the field of biological medicines, and particularly discloses application of a Ptprj agonist GJ103 in preparation of a medicine for treating acute kidney injury (AKI) induced by cisplatin. In-vivo and in-vitro experiments prove that the GJ103, by activating Ptprj, can significantly down-regulate expression of pro-apoptotic protein Bax and Cleved Caspase-3, up-regulate anti-apoptotic protein Bcl2 and reduce infiltration of inflammatory factors TNF-alpha and IL-6, so that apoptosis and inflammatory response of renal tubular epithelial cells are relieved. In in-vivo experiments, GJ103 (20-40mg / kg / day) can reduce serum creatinine and urea nitrogen levels of cis-platinum model mice and improve pathological injuries such as renal tubule dilatation; in in-vitro experiments, 20-40 [mu] M of GJ103 can inhibit apoptosis of renal tubular epithelial cells and reduce expression of renal injury markers NGAL and Kim-1. The pharmaceutical composition contains GJ103 and a pharmaceutical carrier, the preparation form can be a 4mg / mL injection (the purity is greater than or equal to 99.46%) or an oral preparation, and a new strategy is provided for clinical treatment of cisplatin renal toxicity.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of medicine, and particularly relates to the application of a Ptprj agonist GJ103 in the preparation of a drug for treating cisplatin-induced acute kidney injury. BACKGROUND

[0002] Acute kidney injury (AKI) is a clinical critical illness characterized by a rapid decline in kidney function, and its causes include infection, ischemia and hypoxia, and drugs. AKI patients often have multiple system complications and can develop multiple organ failure. A meta-analysis covering a global range and involving more than 3.5 million people showed that the proportion of community-acquired AKI among outpatients was about 8.3%, and the proportion of hospital-acquired AKI among all inpatients reached 20%-31.7% [1] . The prognosis of AKI patients is not optimistic, and most patients have varying degrees of kidney damage, which can develop into chronic kidney disease and eventually progress to end-stage renal disease [2] , causing great spiritual and economic burden to families and society. In recent years, although a large number of studies have been conducted on the pathogenesis and intervention strategies of AKI, the specific mechanism of AKI is still not very clear, and there is a lack of effective prevention and treatment methods in clinical practice. Therefore, it is of great significance to further explore the mechanism of AKI in order to find effective clinical intervention targets and improve the prognosis of AKI patients.

[0003] Ptprj, a protein tyrosine phosphatase receptor J, is expressed in hematopoietic cells, endothelial cells, fibroblasts, thyroid cells and breast cells [3] . Ptprj is composed of a single intracellular catalytic PTP domain, a transmembrane domain and an extracellular domain, and is involved in important physiological and pathological processes such as cell proliferation and differentiation, cell migration and angiogenesis by specifically removing the phosphate groups of tyrosine residues on other proteins [4] . In our previous study, we found that Meis1 inhibited the proliferation and activation of fibroblasts by activating Ptprj transcription, thereby improving kidney fibrosis [5] . At present, the role of Ptprj in acute kidney injury has not been studied. GJ103 is a GJ072 analog that can induce readthrough of premature stop codons and has research potential in genetic diseases caused by nonsense mutations [6] . As a small molecule agonist of Ptprj, GJ103 therapy significantly attenuates the deposition of extracellular matrix and the activation of fibroblasts in obstructed or ischemic kidney tissues and TGF-beta 1-induced cells [5] , and has great potential in the treatment of chronic kidney disease. There is no report on the use of GJ103 in AKI.

[0004] References:

[0005] 1. Kellum JA, Romagnani P, Ashuntantang G, Ronco C, Zarbock A, Anders HJ. Acute kidney injury. Nat Rev Dis Primers. 2021;7(1):52.

[0006] 2. Wang Z, Zhang C. From AKI to CKD: Maladaptive Repair and the Underlying Mechanisms. Int J Mol Sci. 2022;23(18).

[0007] 3. Shalev M, Arman E, Stein M, Cohen-Sharir Y, Brumfeld V, Kapishnikov S, Royal I, Tuckermann J, Elson A. PTPRJ promotes osteoclast maturation and activity by inhibiting Cbl-mediated ubiquitination of NFATc1 in late osteoclastogenesis. FEBS J. 2021 Aug;288(15):4702-4723. doi: 10.1111 / febs.15778. Epub 2021 Mar 5. PMID: 33605542.

[0008] 4. Li H, Zhang P, Liu C, Wang Y, Deng Y, Dong W, et al. The Structure, Function and Regulation of Protein Tyrosine Phosphatase Receptor Type J and Its Role in Diseases. Cells. 2022;12(1).

[0009] 5. Bai M, Xu S, Jiang M, Guo Y, Hu D, He J, et al. Meis1 Targets Protein Tyrosine Phosphatase Receptor J in Fibroblast to Retard Chronic Kidney Disease Progression. Adv Sci (Weinh). 2024; 11(39): e2309754.

[0010] 6. Du L, Jung ME, Damoiseaux R, Completo G, Fike F, Ku JM, Nahas S, Piao C, Hu H, Gatti RA. A new series of small molecular weight compounds induce read through of all three types of nonsense mutations in the ATM gene. Mol Ther. 2013 Sep;21(9):1653-60. doi: 10.1038 / mt.2013.150. Epub 2013 Jun 18. PMID: 23774824; PMCID: PMC3776636. SUMMARY

[0011] To solve the above problems, the application discloses application of a Ptprj agonist GJ103 in preparation of a drug for treating cisplatin-induced acute kidney injury.

[0012] The application surprisingly found that the Ptprj agonist GJ103 can be used in preparation of a drug for treating cisplatin-induced acute kidney injury. In order to further explore the role of Ptprj in AKI, we bred Ptprj heterozygous knockout mice and established a cisplatin-induced AKI model. The results show that after Ptprj knockdown, the renal function, renal pathological injury and tubular damage of cisplatin-induced AKI mice are significantly aggravated. The above data highly suggest that Ptprj may play an important role in the treatment of AKI. Subsequently, we treated cisplatin-induced acute kidney injury with a small molecule agonist GJ103 of Ptprj. The results show that, compared with the cisplatin group, after GJ103 treatment, the increase of creatinine and urea nitrogen in mice is significantly inhibited, and the pathological manifestations such as renal tubular dilation and brush border disappearance caused by cisplatin are significantly improved. And GJ103 further reduces the damage, apoptosis and inflammatory factor infiltration of renal tubules.

[0013] In vitro experiments show that in TKPTs cells, overexpression of Ptprj inhibits the expression of Bax and C-Caspase3 (pro-apoptotic proteins) induced by cisplatin, and promotes the expression of Bcl2 (anti-apoptotic protein) and reduces the infiltration of inflammatory factors. And down-regulation of Ptprj expression aggravates the apoptosis and inflammatory response of TKPTs cells induced by cisplatin. Similarly, GJ103-20 and 40uM concentrations are administered to TKPTs cells to treat cisplatin-induced renal tubular damage. The results show that GJ103-40uM achieves better therapeutic effect. The main performance is: the decrease of pro-apoptotic C-Caspase3 and the increase of anti-apoptotic Bcl2, and the decrease of inflammatory factor infiltration. The above results show that the application provides a new intervention target and potential drug for clinical AKI, which has important scientific significance and value. GJ103 has great potential in the preparation of drugs for treating acute kidney injury, and can effectively reduce the damage, apoptosis and inflammatory response of renal tubules.

[0014] Based on the above research, the application includes the following technical solutions:

[0015] The application of Ptprj agonist GJ103 in the preparation of a drug for treating cisplatin-induced acute kidney injury.

[0016] Further, the above application, the drug contains a therapeutically effective amount of GJ103 and a pharmaceutically acceptable carrier, and the dosage form of the drug is an injection or an oral preparation.

[0017] Further, the above application, the drug activates Ptprj, down-regulates the expression of pro-apoptotic proteins Bax and Cleaved Caspase-3, up-regulates the expression of anti-apoptotic protein Bcl2, and reduces the infiltration of inflammatory factors TNF-α and IL-6.

[0018] Further, the above application, the drug is administered at a dose of 20-40mg / kg / day.

[0019] The application also discloses the application of Ptprj agonist GJ103 in the preparation of a reagent for inhibiting cisplatin-induced apoptosis of renal tubular epithelial cells in vitro, characterized in that the concentration of the reagent is 20-40μM.

[0020] The application also discloses a pharmaceutical composition for treating cisplatin-induced acute kidney injury, comprising:

[0021] a) Ptprj agonist GJ103;

[0022] b) a pharmaceutically acceptable carrier;

[0023] Further, the above pharmaceutical composition also comprises a cisplatin nephrotoxicity antagonist.

[0024] The application also discloses a pharmaceutical preparation for treating cisplatin-induced acute kidney injury, characterized in that:

[0025] a) the active ingredient is Ptprj agonist GJ103, and the purity is greater than or equal to 99.46 %;

[0026] b) the preparation form is an injection, and the concentration is 4 mg / mL.

[0027] Further, the administration dose of the injection of the above pharmaceutical preparation is 40 mg / kg / day.

[0028] The application also discloses application of the Ptprj agonist GJ103 in preparation of a medicine for reducing kidney injury biomarkers, the biomarkers including at least one of NGAL, Kim-1, Bax and Cleaved Caspase-3.

[0029] Compared with the prior art, the application has the following outstanding advantages:

[0030] The application discloses, for the first time, a core mechanism of Ptprj agonist GJ103 in treating cisplatin-induced acute kidney injury (AKI) by targeting and regulating tubular cell apoptosis and inflammation pathways: activation of Ptprj can synergistically down-regulate pro-apoptotic proteins (Bax and Cleaved Caspase-3), up-regulate anti-apoptotic proteins (Bcl2), and significantly inhibit inflammatory factors such as TNF-alpha and IL-6, thereby blocking the core pathological process of AKI from the molecular level. Compared with the prior art, the application has three outstanding advantages:

[0031] 1. Mechanism originality: breaking through the predicament of lacking targeted therapeutic drugs for AKI, and for the first time, Ptprj is determined as a new target point for intervention of AKI, thereby providing a new direction for drug research and development;

[0032] 3. Therapeutic efficiency: GJ103 has the dual functions of rapidly inhibiting cell apoptosis and anti-inflammation, is suitable for acute intervention of cisplatin nephrotoxicity, and existing in-vitro experiments prove that the biological safety is good;

[0033] 3. Clinical transformation potential:

[0034] An injectable / oral stable preparation is provided, which is especially suitable for being combined with a cisplatin chemotherapy scheme, and prevents dose-dependent kidney injury;

[0035] The application expands the application scenarios of GJ103 from chronic kidney disease (anti-fibrosis) to acute kidney injury (anti-apoptosis / anti-inflammation), highlights the "one drug with multiple effects" value, and provides a solution to an urgent need for prevention and treatment of clinical AKI. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1Ptprj heterozygous knockout mice aggravated cisplatin-induced kidney injury: A: mouse serum creatinine and blood urea nitrogen; B & C: representative images of mouse kidney tissue PAS staining and tubular injury score; D & E: apoptosis in mouse kidney tissue and quantification; F & G: qRT-PCR and Western Blot detection of mRNA and protein expression in mouse kidney tissue.

[0037] Figure 2 Treatment of GJ103 alleviated cisplatin-induced acute kidney injury in mice: A: mouse serum creatinine and blood urea nitrogen; B: mouse serum creatinine and blood urea nitrogen; C & D: representative images of mouse kidney tissue PAS staining and tubular injury score; E & F: apoptosis in mouse kidney tissue and quantification; G & H: qRT-PCR and Western Blot detection of mRNA and protein expression in mouse kidney tissue.

[0038] Figure 3 Overexpression of Ptprj alleviated cisplatin-induced renal tubular epithelial cell injury, apoptosis and inflammatory response: A: qRT-PCR detection of mRNA expression in mouse kidney tissue; B: Western Blot detection of protein expression in mouse kidney tissue.

[0039] Figure 4 Down-regulation of Ptprj aggravated cisplatin-induced renal tubular epithelial cell injury, apoptosis and inflammatory response: A: qRT-PCR detection of mRNA expression in mouse kidney tissue; B: Western Blot detection of protein expression in mouse kidney tissue.

[0040] Figure 5 Treatment of GJ103 improved cisplatin-induced renal tubular epithelial cell injury, apoptosis and inflammatory response: A: qRT-PCR detection of mRNA expression in mouse kidney tissue; B: Western Blot detection of protein expression in mouse kidney tissue. DETAILED DESCRIPTION

[0041] The present application will be further illustrated below with specific examples. Unless otherwise specified, the reagents used in the present application are commercially available reagents. Mouse renal tubular epithelial cells (TKPTs) are from ATCC (American Type Culture Collection), Ptprj-KO mice and C57BL / 6J mice are from Jisui Yakang (Nanjing, China).

[0042] The experimental methods and materials used in the following examples are as follows:

[0043] Animal model preparation: To evaluate the role of Ptprj and GJ103 (MCE: HY-101203A; Purity: 99.46%) in AKI, cisplatin-induced AKI model was established. The chemical structure of GJ103 is as follows:

[0044]

[0045] (CAS NO. 1459687-89-8).

[0046] Cisplatin model: Ptprj heterozygous knockout (Ptprj + / - , Het) and wild type mice (Wild Type, WT) were placed in the SPF laboratory of Nanjing Medical University Animal Center. (Mice were free to drink and eat, room temperature about 25℃, humidity about 50%, 12h day and night alternation). Mice were randomly divided into 4 groups (control group: Vehicle+WT group and Vehicle+Het group; model group: Cis+WT group and Cis+Het group). Cisplatin administration: 8mL of normal saline was added to 20mg of cisplatin powder to make a 2.5mg / mL working solution. Control group mice were injected intraperitoneally with normal saline according to body weight, and model group mice were injected intraperitoneally with cisplatin at 25mg / kg. Three days after administration, the mice were euthanized, and heart blood was drawn and kidney tissue was reserved.

[0047] Cisplatin model was constructed to evaluate the effect of GJ103 on AKI. 5mL of sterilized double distilled water was added to 20mg of GJ103 powder to make a 4mg / mL working solution. 8-week-old male C57BL / 6J mice were randomly divided into 3 groups (Cis group, Cis+GJ103-20mg / kg / day group and Cis+GJ103-40mg / kg / day group). After the mice were pretreated with GJ103 (20 and 40mg / kg / day) by intraperitoneal injection for 1 day, cisplatin treatment was given, as described above. Subsequent 3-day continuous treatment with GJ103 was given. Three days after cisplatin, the mice were euthanized, and the remaining steps were the same as above.

[0048] According to the experimental results, GJ103-40mg / kg / day achieved better therapeutic effect, and the experimental results were further improved. 8-week-old male C57BL / 6J mice were randomly divided into 3 groups (control group: Vehicle group; model group: Cisplatin group and Cisplatin+GJ103-40mg / kg / day group). After the mice were pretreated with GJ103 (40mg / kg / day) by intraperitoneal injection for 1 day, cisplatin treatment was given, as described above. Subsequent 3-day continuous treatment with GJ103 was given. Three days after cisplatin, the mice were euthanized, and the remaining steps were the same as above.

[0049] After the animals were euthanized, the serum from heart blood was sent to the automatic biochemical analyzer of Nanjing Children's Hospital for blood biochemical analysis. The kidney tissues for histological analysis were fixed in 4% paraformaldehyde, and the remaining kidney tissues were stored at -80°C for subsequent mRNA and protein analysis.

[0050] Histological analysis: Kidney tissues were fixed in 4% paraformaldehyde for more than 24 hours, dehydrated and embedded. Paraffin sections (3 μm) were deparaffinated and hydrated, then stained with PAS to show kidney pathological manifestations such as renal tubular basement membrane, and photographed under a microscope for semi-quantitative scoring of tubular injury.

[0051] Periodic acid-Schiff (PAS) staining: PAS-stained pathological sections were observed under a microscope, and kidney pathological tissue morphology was observed. The pathological injury score was improved by Broekema's blind method, that is, 5-10 non-overlapping high-power fields (x200) were randomly selected for each section, and five main acute kidney injury-related manifestations were observed: (brush border loss, tubular dilation, cast formation, tubular necrosis, and neutrophil infiltration). The score is as follows: the proportion of tubular injury in any unit: (1) normal renal tubules, 0 points; (2) injury <25%, 1 point; (2) injury >25% and <50%, 2 points; (3) injury >50% but <75%, 3 points; (4) >75%, 4 points.

[0052] TUNEL: The TUNEL staining technique was used to detect the apoptosis level of renal tubular epithelial cells in mouse kidneys (6 non-overlapping high-power fields were taken, and the proportion of positive cell number of renal tubular epithelial cells was calculated).

[0053] Real-time quantitative PCR: RNA isoPlus reagent was used to extract total RNA from tissues or cells. qPCR reverse transcription was performed using HiScript II QRT SuperMix. Real-time PCR amplification was performed on a LightCycler 96 instrument real-time PCR detection system using AceQ qPCR SYBR Green Master Mix. GAPDH was used as an internal reference, and the relative value was calculated using the ΔΔCt method.

[0054] Western Blot: Tissues or cells were lysed with RIPA buffer containing protease inhibitors. Samples were centrifuged at 12,000 rpm for 15 min. Protein concentrations were determined using a BCA protein assay kit. Equal masses of samples were spotted onto a polyacrylamide gel, which was then transferred to a PVDF membrane. The PVDF membrane was blocked with 5% skim milk for 1 h, followed by overnight incubation with antibodies against NGAL (1:3000), Bax (1:1000), C-Caspase3 (1:1000), Bcl2 (1:1000), and GAPDH (1:10000). Bands were visualized using an Amersham Biosciences ECL detection system. Relative quantification of grayscale values ​​was performed using ImageJ.

[0055] Cell Culture and Drug Administration / Transfection / Stimulation: TKPTs cells were grown adherently in DMEM-F12 medium supplemented with 7% FBS and incubated at 37°C with 5% CO2. Cells were passaged with 0.25% trypsin at 70-80% confluence. In specific experiments, cells were pretreated with GJ103 for 2 hours or transfected with Ptprj plasmid and siPtprj for 6 or 24 hours, followed by stimulation with cisplatin (5 μg / mL). Cells were collected for mRNA analysis after 24 hours or for protein analysis after 48 hours.

[0056] Statistical analysis: Results are expressed as mean ± SEM. Statistical analysis was performed using GraphPad Prism 8 software. Two-tailed Student's t-tests were used to analyze differences between two groups, and one-way ANOVA was used for comparisons among multiple groups. A p-value < 0.05 was considered statistically significant.

[0057] Example 1

[0058] Ptprj heterozygous knockout mice exacerbate cisplatin-induced kidney damage.

[0059] Considering the possibility of embryonic death in Ptprj homozygous knockout mice, we bred Ptprj heterozygous knockout mice to establish a cisplatin model. Experimental results showed that knocking down Ptprj significantly increased cisplatin-induced blood urea nitrogen and serum creatinine levels. Figure 1 A), further aggravating kidney pathological damage ( Figure 1 B&C). TUNEL staining showed that compared with the cisplatin group, the number of TUNEL-positive cells was significantly increased in the Ptprj knockdown group, indicating that decreased Ptprj expression leads to increased renal tubular cell apoptosis. Figure 1 D&E). Western blotting and qRT-PCR showed that under cisplatin stimulation, low expression of Ptprj also significantly increased the expression of NGAL (distal tubular injury), Bax (pro-apoptotic protein), and MCP1 (inflammatory factor) in the kidneys.Figure 1 The above results indicate that Ptprj heterozygous knockout mice exacerbate cisplatin-induced kidney damage.

[0060] Example 2

[0061] GJ103 treatment alleviated cisplatin-induced acute kidney injury in mice.

[0062] Further validation of the protective effect of GJ103 in AKI was conducted in a cisplatin model. Previously, our research group treated mice with UUO and UIRI-induced chronic kidney disease using GJ103-15 and 30 mg / kg / day. The results showed that GJ103-30 mg / kg / day achieved better therapeutic effects, suggesting a possible dose-dependent effect of GJ103 in treating kidney diseases. More importantly, acute kidney injury is a clinical syndrome characterized by a sudden and rapid decline in renal function, with a narrow therapeutic window, requiring effective blood drug concentrations to be achieved within a short period. Therefore, in our previous experiments to explore the therapeutic concentration of GJ103 in AKI, we selected 20 and 40 mg / kg / day. C57BL / 6J mice were pretreated with GJ103-20 and 40 mg / kg / day one day before cisplatin injection, followed by daily treatment for three consecutive days. As shown in the figure, compared with the Cis+GJ103-20mg / kg / day group, the GJ103-40mg / kg / day group significantly reduced cisplatin-induced creatinine and urea nitrogen levels in mice. Figure 2 A). Subsequently, we further refined the experiment using GJ103 at a dose of 40 mg / kg / day. Results showed that the therapeutic dose of GJ103 significantly reduced blood urea nitrogen and serum creatinine levels (A). Figure 2 B) Reduces the degree of pathological damage to the kidneys. This is mainly manifested in a reduction of pathological features such as renal tubular dilation, loss of the brush border, and casts. Figure 2 C&D). TUNEL and WB results showed that GJ103 treatment could alleviate cisplatin-induced renal tubular apoptosis and damage. Similarly, the mRNA expression of pro-apoptotic proteins such as Bax and IL-6 was further reduced. Figure 2 EH). The above experiments show that the Ptprj agonist GJ103 plays a certain protective role in AKI.

[0063] Example 3

[0064] Overexpression of Ptprj reduces cisplatin-induced renal tubular epithelial cell damage, apoptosis, and inflammatory response.

[0065] In vitro cultured TKPTs cell line, Ptprj overexpression plasmid was transfected and then cisplatin was given for 24h. The results showed that overexpression of Ptprj reduced the mRNA levels of Kim1, NGAL, and inflammatory factors IL-18, MCP1, and TNF-α caused by cisplatin-induced renal tubular injury. At the same time, the expression of pro-apoptotic proteins Bax and C-Caspase3 was also significantly decreased, and the expression of anti-apoptotic protein Bcl-2 was increased. Figure 3 A&B).

[0066] Example 4

[0067] Down-regulation of Ptprj aggravates cisplatin-induced renal tubular epithelial cell injury, apoptosis and inflammatory response

[0068] We transfected siPtprj knockdown sequence in TKPTs cells for 24h and then gave cisplatin treatment. The results showed that the decrease in Ptprj expression promoted the mRNA expression of Kim1, IL-18, and MCP1 inflammatory factors caused by cisplatin-induced renal tubular injury. At the same time, knockdown of Ptprj also up-regulated the expression of pro-apoptotic protein C-Caspase3 induced by cisplatin, and inhibited the expression of anti-apoptotic protein Bcl-2 Figure 4 A&B).

[0069] Example 5

[0070] GJ103 treatment improves cisplatin-induced renal tubular epithelial cell injury, apoptosis and inflammatory response

[0071] GJ103 is a read-through compound that can induce read-through of premature stop codons and has research potential in genetic diseases caused by nonsense mutations. In chronic kidney disease, CJ103 treatment can improve renal fibrosis caused by obstruction and ischemia in mice. The above in vivo experiments show that GJ103 can also improve acute kidney injury caused by nephrotoxicity. Subsequently, we evaluated the protective effect of GJ103 in in vitro experiments. TKPTs cells were pretreated with 20, 40μM 2 concentrations for 2h, and then cisplatin was given for stimulation. qRT-PCR results show that GJ103 treatment alone does not cause cell damage, indicating good biological safety. Consistent with the in vivo results, GJ103 treatment not only reduces the expression of Kim1, Bax, C-Caspase3, and inflammatory factors, but also promotes the expression of anti-apoptotic protein Bcl-2 Figure 5 A&B).

[0072] The results of in vivo and in vitro experiments collectively show that Ptprj and its small molecule agonist GJ103 significantly reduce cisplatin-induced renal tubular injury, apoptosis and inflammatory response. GJ103 has great potential in the preparation of drugs for the treatment of acute kidney injury, and the completion of this application provides a new treatment strategy for the relief of AKI.

[0073] Summary:

[0074] The above example results show that Ptprj heterozygous knockout mice aggravate cisplatin-induced renal tubular injury, while its agonist GJ103 significantly improves cisplatin-induced acute kidney injury. Similarly, overexpression of Ptprj and G103 treatment significantly alleviates cisplatin-induced renal tubular epithelial cell injury and apoptosis, and reduces inflammatory response. On the contrary, knockdown of Ptprj aggravates renal tubular injury. The above results show that GJ103 has great potential in the preparation of drugs for the treatment of acute kidney injury. The completion of the present application provides a new treatment strategy for acute kidney injury.

[0075] GJ103, as an agonist of Ptprj, exhibits completely different mechanisms of action in chronic kidney disease and acute kidney injury, reflecting the pleiotropic effects of the drug in the treatment of kidney diseases.

[0076] In the UUO and UIRI-induced CKD model, GJ103 significantly inhibits the phosphorylation of PDGFRβ by activating Ptprj, thereby blocking the proliferation and activation of fibroblasts, and ultimately reducing the progression of renal fibrosis. This mechanism is highly consistent with the pathological characteristics of CKD - the core of CKD is the continuous activation of fibroblasts and extracellular matrix deposition, leading to structural remodeling and loss of function of the kidney. GJ103 effectively delays the progression of fibrosis by interfering with the PDGFRβ signaling pathway, and long-term low-dose administration is required to maintain therapeutic effect.

[0077] However, the mechanism of action of GJ103 in cisplatin-induced acute kidney injury model is completely different. After activating Ptprj, GJ103 significantly down-regulates the expression of pro-apoptotic proteins (Bax, Cleaved Caspase-3), while up-regulating anti-apoptotic proteins (Bcl2), thereby inhibiting the apoptosis of renal tubular epithelial cells. In addition, GJ103 can also reduce the infiltration of inflammatory factors (such as TNF-α, IL-6), and reduce the acute inflammatory response of the kidney. These effects collectively protect renal tubular epithelial cells from damage by nephrotoxic drugs such as cisplatin, and promote rapid recovery of kidney function. Since the pathological process of AKI is acute, high-concentration drug intervention is required within a short period of time, therefore GJ103 needs to adopt a large-dose shock treatment strategy in this indication.

[0078] In summary, the therapeutic effects of GJ103 in CKD and AKI depend on different downstream signaling pathways: in CKD, its core mechanism is to inhibit PDGFRβ-mediated fibrosis; while in AKI, it exerts renoprotective effects by regulating apoptosis and inflammatory pathways. This difference not only reflects the complexity of the Ptprj signaling pathway, but also indicates that the treatment strategy of GJ103 in different kidney diseases needs to be optimized according to the pathological mechanism. The findings of this study provide a strong and new theoretical basis for the clinical application of GJ103 in the treatment of AKI, and its anti-apoptotic and anti-inflammatory effects may provide a new intervention target for the treatment of AKI, which currently lacks specific drugs.

[0079] The above shows and describes the basic principles, main features and advantages of the present application. Those skilled in the art should understand that the above examples do not limit the present application in any form, and any technical solutions obtained by equivalent replacement or equivalent transformation fall within the scope of the present application.

Claims

1. Use of Ptprj agonist GJ103 in the preparation of a medicament for treating cisplatin-induced acute kidney injury.

2. Use according to claim 1, characterized in that, The medicament comprises a therapeutically effective amount of GJ103 and a pharmaceutically acceptable carrier, and the dosage form of the medicament is an injection or an oral preparation.

3. Use according to claim 1, characterized in that, The medicament activates Ptprj, down-regulates the expression of pro-apoptotic proteins Bax and Cleaved Caspase-3, up-regulates the expression of anti-apoptotic protein Bcl2, and reduces the infiltration of inflammatory factors TNF-α and IL-6.

4. Use according to any one of claims 1 to 3, characterized in that, The administration dose of the medicament is 20-40 mg / kg / day.

5. Use of a Ptprj agonist GJ103 in the preparation of an agent for inhibiting cisplatin-induced apoptosis of renal tubular epithelial cells in vitro, characterized in that, The concentration of the agent is 20-40 μM.

6. A pharmaceutical composition for treating cisplatin-induced acute kidney injury, characterized by, Comprise: a) Ptprj agonist GJ103; b) a pharmaceutically acceptable carrier.

7. The pharmaceutical composition of claim 6, wherein, Also comprising a cisplatin nephrotoxicity antagonist.

8. A pharmaceutical preparation for treating cisplatin-induced acute kidney injury, characterized in that: a) the active ingredient is Ptprj agonist GJ103 with a purity of ≥ 99.46%; b) the preparation form is an injection with a concentration of 4 mg / mL.

9. The pharmaceutical preparation according to claim 8, characterized in that, The administration dose of the injection is 40 mg / kg / day.

10. Use of a Ptprj agonist GJ103 in the manufacture of a medicament for reducing a biomarker of kidney injury, characterized in that, The biomarkers include at least one of NGAL, Kim-1, Bax, and Cleaved Caspase-3.

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