Application of lactic acid modified PCBP1 protein as drug target for screening drugs for preventing, relieving or treating renal fibrosis

Abstract

The invention discloses application of lactic acid modified PCBP1 protein as a drug target for screening drugs for preventing, relieving or treating renal fibrosis, and belongs to the technical field of biomedicine. The invention provides an accurate conversion path from a macroscopic metabolic phenomenon to a microcosmic drug target aiming at the defect of lack of a specific treatment target aiming at metabolic abnormality, and has the advantages of strong targeting property and clear intervention window.

Description

Technical Field

[0001] This invention relates to the field of biomedical technology, specifically to the application of lactated PCBP1 protein as a drug target for screening drugs to prevent, alleviate or treat renal fibrosis. Background Technology

[0002] Chronic kidney disease (CKD) is a global public health problem, and its end-stage renal disease (ESRD) poses a serious threat to human health. Renal fibrosis is the common pathological basis for the irreversible progression of almost all CKD to ESRD, characterized by excessive activation of myofibroblasts and massive deposition of extracellular matrix (ECM) in the renal interstitium. Currently, there are no specific targeted drugs in clinical practice that can effectively block or reverse renal fibrosis, making the development of novel therapies targeting the core mechanisms of fibrosis an urgent priority.

[0003] At the molecular level, polycytosine-binding protein 1 (PCBP1), as an important RNA-binding protein, has been reported to participate in various biological processes such as cell proliferation, apoptosis, iron metabolism, and immune responses. Recent studies have preliminarily suggested that PCBP1 may play a role in tissue fibrosis (such as liver fibrosis), but its specific function in renal fibrosis remains controversial, and the precise molecular switches regulating its activity have not been fully elucidated.

[0004] On the other hand, lactylation is a newly discovered post-translational modification of proteins driven by intracellular lactate levels. It dynamically regulates the function of target proteins by covalently linking a lactate group to a lysine residue, and is considered a key bridge connecting cellular metabolic state and cellular functions such as gene expression. Lactylation has been shown to play an important role in processes such as tumor immunity and macrophage polarization. However, research on this modification in chronic progressive organ fibrosis, particularly renal fibrosis, is almost nonexistent. Currently, no studies have revealed whether the PCBP1 protein can undergo lactylation, let alone explored whether and how this modification affects PCBP1 function and thus participates in the regulation of renal fibrosis. Summary of the Invention

[0005] The main objective of this invention is to elucidate the precise functional role of PCBP1 protein in renal fibrosis and its precise regulatory mechanism. Addressing the predicament of unclear function of PCBP1 in renal fibrosis and lack of effective regulatory means in the prior art, this invention aims to reveal for the first time the novel post-translational modification event of lactation of PCBP1 protein, and to clarify that this modification is a key molecular switch for precisely regulating the function of PCBP1 protein in promoting renal fibrosis, thereby resolving its functional controversy and providing a novel pharmacological intervention interface.

[0006] To achieve the above objectives, this application adopts the following technical solution: In a first aspect, the present invention provides a biomarker that can be used for the auxiliary diagnosis of renal fibrosis, wherein the biomarker is a lactated PCBP1 protein.

[0007] Secondly, this invention provides the application of lactolyzed PCBP1 protein as a drug target for screening drugs to prevent, alleviate or treat renal fibrosis.

[0008] In the above technical solution, the lactated PCBP1 protein is the PCBP1 protein lactated at position K115.

[0009] In the above technical solutions, the renal fibrosis disease is renal fibrosis characterized by metabolic remodeling and chronic inflammation.

[0010] Thirdly, the present invention provides the application of substances that target and interfere with lactate modification of PCBP1 protein in the preparation of drugs for the prevention, relief or treatment of renal fibrosis.

[0011] In the above technical solution, the substance that targets and interferes with the lactate modification of PCBP1 protein is the PCBP1-K115R mutant.

[0012] Fourthly, the present invention provides a medicament for treating renal fibrosis, wherein the medicament contains a substance that targets and interferes with lactate modification of PCBP1 protein.

[0013] Fifthly, the present invention provides the use of the PCBP1-K115R mutant in medicaments for treating, alleviating or preventing renal fibrosis.

[0014] In the above technical solutions, the drugs for treating, alleviating or preventing renal fibrosis contain other pharmaceutically acceptable excipients or carriers.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: 1) This invention provides an application of lactic acid-modified PCBP1 protein as a drug target for screening drugs to prevent, alleviate or treat renal fibrosis. In view of the lack of specific therapeutic targets for metabolic abnormalities, this invention provides a precise conversion path from macroscopic metabolic phenomena to microscopic druggable targets, which has the advantages of strong targeting and clear intervention window. 2) In in vitro and in vivo renal fibrosis models, this invention found that the lactation modification level of PCBP1 protein is positively correlated with the degree of fibrosis. By constructing a mutant of the lactation modification site of PCBP1 protein (such as mutating the speculated lysine site to arginine to simulate the non-lactation state), it was confirmed in the cell model that the mutation can significantly weaken the pro-fibrotic function of PCBP1, directly proving that lactation modification is the key switch for regulating PCBP1 function. 3) This invention delivers PCBP1-K115R and PCBP1-K115T mutants carrying key site point mutations into mice via a lentiviral vector. The PCBP1-K115R mutant significantly improves UIRI-induced renal fibrosis, as evidenced by reduced serum creatinine and urea nitrogen levels, decreased collagen deposition, and downregulation of fibrosis markers (fibronectin, α-SMA, and collagen I). Immunofluorescence of kidney tissue showed a significant decrease in the expression of α-SMA and fibronectin in the interstitium. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a heatmap of lactation modification of mouse kidney tissue in Example 1 of the present invention; Figure 2 This is a statistical diagram of differentially lactated modified proteins and sites in Example 1 of the present invention; Figure 3 This is a diagram verifying the lactation level at site K115 of the PCBP1 protein in Example 1 of the present invention. Figure 4 This is a schematic diagram showing the results of Western Blotting detection of fibrosis-related protein expression levels in TCMK-1 cells of each treatment group in Example 2 of the present invention; Figure 5 This is a diagram showing the expression of ferrophagy-related proteins NCOA4, ATG5, Beclin 1, and the autophagy marker LC3 as detected by Western blotting in Example 2 of this invention. Figure 6 This is a figure showing the results of an in vivo study on the reduction of renal fibrosis in mice by inhibiting PCBP1 lactation in Example 3 of the present invention.

[0018] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0019] To avoid unnecessary details, unless otherwise specified, all items used in the following examples are commercially available products, and all methods used are conventional methods unless otherwise specified.

[0020] Example 1 A study identifying the upregulation of lactation modification of PCBP1 protein in fibrotic kidneys 1. Experimental Materials and Methods 1.1 Animal handling Healthy male C57BL / 6 mice, 8 weeks old and weighing 20±2g, were purchased from Beijing Vital River Laboratory Animal Technology Co., Ltd. All mice were housed in an SPF-grade clean environment with a temperature maintained at 20±2℃, humidity at 50-60%, 12-hour alternating light and dark, and free access to food and water.

[0021] 1.2 Experimental reagents The Anti-L-Lactyl Lysine Rabbit mAb antibody was purchased from Hangzhou Jingjie Biotechnology Co., Ltd.

[0022] 2. Experimental Methods 2.1 Constructing an animal model Eight-week-old male C57BL / 6 mice were randomly divided into a sham-operated group (Sham) and an ischemia-reperfusion injury group (UIRI), with six mice in each group, after one week of acclimatization. The UIRI model was established as follows: After anesthesia induction, a midline abdominal incision was made to expose the left renal pedicle. The pedicle was clamped with vascular clamps for 35 minutes, while maintaining core body temperature at 37°C throughout the ischemia period. Finally, the abdominal cavity and skin were sutured layer by layer. On day 10 post-surgery, a contralateral nephrectomy was performed. In the Sham group, only the abdominal cavity was opened and the left ureter was freed; no ligation was performed. On day 11 post-modeling, the mice were sacrificed, and blood and kidney samples were collected for analysis.

[0023] 2.2 Lactation modification omics analysis of kidney tissue (commissioned to Hangzhou Jingjie Biotechnology Co., Ltd.) 2.2.1 Protein extraction and quantification: Three kidney tissue samples were taken from mice in the Sham group and UIRI group, and RIPA lysis buffer containing protease inhibitor (1 mL / 100 mg tissue) was added. The tissue was sonicated on ice (300 W power, 3 s operation time, 5 s interval, 30 times in total), and centrifuged at 12000 rpm for 15 min at 4 °C. The supernatant was collected.

[0024] The sample (1 mL / 100 mg tissue) was rapidly lysed using a strong denaturing lysis buffer containing a protease inhibitor (RIPA lysis buffer) to maximize the preservation of the modification signal. After centrifugation to remove impurities, the protein concentration was detected using the BCA kit from Yaxin. The procedure was as follows: Add 20 μL of standard solution (0, 0.025, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5 mg / mL) to each well of a 96-well plate. The standard solution was bovine serum albumin solution. Add 20 μL of the protein sample to be tested (pre-diluted 5-fold) to each well of the sample plate. Prepare the working solution using solutions A and B from the BCA kit. Solution A mainly consists of sodium carbonate, sodium bicarbonate, sodium tartrate, etc., dissolved in a strong alkaline sodium hydroxide solution. Solution B mainly consists of a high-concentration aqueous solution of disodium BCA. The working solution was calculated based on a volume ratio of A:B = 50:1. Add 200 μL of BCA working solution to each well. Mix thoroughly using a pipette, avoiding air bubbles. Cap the plate and incubate at 37°C for 30 minutes. Remove the plate and allow it to cool to room temperature. Measure the absorbance of each well at 562 nm using a microplate reader. Plot a standard curve and calculate the sample concentration; quantify the total protein, ensuring consistent sample loading for each sample.

[0025] 2.2.2 Enrichment of lactated peptides: First, disulfide bonds were reduced using dithiothreitol, and cysteine ​​residues were stabilized by alkylation with iodoacetamide. The reduced-alkylated protein solution was diluted with at least 10 volumes of 50 mM TEAB buffer. Trypsin was added at an enzyme-to-protein ratio of 1:20, and overnight digestion was performed at 37°C for 12-16 hours. Formic acid was added to a final concentration of 1% (pH 2-3) to irreversibly inactivate the trypsin. After digestion, the peptides were desalted and purified using a C18 solid-phase extraction column, following these steps: the column was sequentially passed through acetonitrile, acetonitrile / water solution containing 0.1% formic acid, and 0.1% formic acid water to solubilize the packing material and establish an acidic environment. The acidified peptide solution was slowly loaded to allow peptide binding. The peptides were washed with sufficient 0.1% formic acid water to completely remove salts. The peptides were then eluted with 30-50% acetonitrile (containing 0.1% formic acid) solution into a new tube. Concentration: The eluent is completely dried using a vacuum centrifuge to obtain peptide powder. It can be stored for a long time at -80℃.

[0026] 2.2.3 Liquid Chromatography-Tandem Mass Spectrometry Analysis: The dried peptides were reconstituted in ice-cold IP buffer and incubated overnight at 4°C with anti-Kla antibody and Protein A / G magnetic beads. The magnetic beads were separated using a magnetic rack, and the peptides were washed three times with ice-cold Tris buffer to remove non-specifically bound peptides. Specifically bound Kla peptides were eluted from the antibody-magnetic bead complex using 0.1% TFA. The enriched peptides were desalted and concentrated, then dried by vacuum centrifugation. Liquid chromatography-tandem mass spectrometry (LC-MS / MS) was used to separate and identify the enriched peptides. Based on the mass spectrometry data, differentially lactated proteins and sites were screened using a series of cutting-edge technologies, including bioinformatics analysis.

[0027] 3. Experimental Results 3.1 Global Analysis of Lactation Modification in Kidney Tissue The lactation modification heatmap based on mass spectrometry quantitative data is as follows: Figure 1 As shown in the figure, the UIRI treatment group and the control group are clearly separated. Red and blue represent the upregulation and downregulation of Kla modification levels, respectively, revealing the global effect of lactate on the modification of specific proteins.

[0028] 3.2 Statistical Analysis of Differentially Lactic Acidification Modified Proteins and Sites Results of lactation modification proteomics analysis as follows Figure 2 As shown in the figure, a total of 33 proteins with upregulated lactation modification and 104 proteins with downregulated lactation modification were screened in the kidneys of mice in the UIRI group. Among them, there were 48 sites with upregulated lactation modification and 197 sites with downregulated lactation modification.

[0029] 3.3 Validation of lactation level at site K115 of PCBP1 protein The bar chart comparing the difference in lactation level at site K115 of PCBP1 protein between the Sham (control) and UIRI (treatment) groups is shown below. Figure 3 As shown in the figure, the differentially regulated lysine lactation (Kla) sites and proteins were compared between the UIRI and Sham groups. Proteomics and modalomics identified a significantly increased lactation modification level of PCBP1 at the K115 site.

[0030] Example 2 Study on the key regulatory role of PCBP1 lactation modification in renal tubular epithelial cell epithelial-mesenchymal transition and ferrophagy 1. Experimental Materials 1.1 Experimental reagents Mouse renal tubular epithelial cells (TCMK-1) were purchased from the Shanghai ATCC cell bank; The mouse-derived PCBP1 overexpression plasmid, the mouse-derived PCBP1 overexpression mutant plasmid, and the negative control plasmid were purchased from Shanghai Genomics Co., Ltd.

[0031] 2. Experimental Methods Experimental Cells and Culture Methods: Mouse renal tubular epithelial cells (TCMK-1) were obtained from the Shanghai ATCC Cell Bank. These cells were cultured in adherent medium using DMEM high-glucose medium containing 10% fetal bovine serum. During passage, the old medium in the culture dish was discarded, 2 ml of sterile PBS buffer was added, gently shaken, and then discarded. 2 ml of trypsin was added for 1 min of digestion. The adherent cells were gently detached, and 2 ml of fresh sterile DMEM high-glucose complete medium was added to terminate the digestion. The cell suspension was transferred to a sterile 15 ml centrifuge tube, centrifuged at 1000 rpm for 5 min at room temperature, the supernatant was discarded, and the cells were resuspended in 1 ml of fresh complete medium. 9 ml of fresh complete medium was added to a clean culture dish, and 300 μL of the cell suspension was transferred to the dish and incubated in a 37°C, 5% CO2 incubator.

[0032] Plasmid construction: Primers PCBP1 were designed and synthesized targeting the multiple cloning site of the GV492 vector. Primer sequences: The full-length coding sequence of mouse PCBP1 was amplified by PCR. The reaction system for PCR amplification of the target gene fragment was prepared as follows: gently pipette to mix, briefly centrifuge, and then place in a PCR instrument for reaction.

[0033] Reaction system: Reaction conditions: 98℃ for 5 min, 98℃ for 10 sec, 58℃ for 10 sec, 72℃ for 1 min / kb 3 , 30 Cycles, 72℃ for 8 min.

[0034] Using a homologous recombination kit, prepare the following reaction mixture in an ice-water bath. Gently mix by pipetting, briefly centrifuge to avoid generating bubbles. Incubate at 37°C for 30 min, then cool in an ice-water bath for 5 min before immediate inversion.

[0035] Reaction system: Add 10 µL of the exchange reaction product to 100 µL of competent cells, gently tap the tube wall several times to mix, and incubate on ice for 30 min. Heat shock at 42℃ for 90 s, then incubate in an ice-water bath for 2 min. Add 500 µL of antibiotic-free LB medium and incubate at 37℃ with shaking for 1 h. Spread an appropriate amount of the bacterial culture evenly onto a plate containing the corresponding antibiotic and incubate upside down in a constant temperature incubator for 12–16 h. Design identification primers; the sequences are as follows: Single colonies were picked using a sterile pipette tip and identified by PCR. The identified positive clones were inoculated into LB broth containing the appropriate antibiotics and cultured at 37°C for 12-16 hours. A suitable amount of the bacterial culture was then sequenced. The sequencing results were compared with the target gene sequence. Plasmids were extracted from the preliminarily identified positive clones and Sanger sequencing was performed to verify the correctness of the PCBP1 sequence, the reading frame, and the integrity of the connection with the vector backbone, ultimately obtaining the PCBP1-WT overexpression plasmid suitable for packaging lentiviruses. Using the constructed PCBP1-WT plasmid as a template, the PCBP1-K115R mutant plasmid was constructed, changing the lysine codon AAG at position 115 to the arginine codon AGG. The mutated sequence was directly inserted into the vector. Positive clone plasmids were extracted following the above steps, and Sanger sequencing was used to verify the successful mutation of the K115 site to AGG, ensuring no additional mutations in other regions of the gene, ultimately obtaining the PCBP1-K115R mutant plasmid.

[0036] Cell transfection and grouping: Well-grown TCMK-1 cells were digested, counted, and seeded evenly in six-well plates at the same density. Transfection was performed when cells reached approximately 50% confluence. TCMK-1 cells were divided into four groups: ① PCBP1-WT overexpression group; ② PCBP1-WT overexpression + sodium lactate group; ③ PCBP1-K115R overexpression group; ④ PCBP1-K115R overexpression + sodium lactate group. Using Lipofectamine 2000, the constructed PCBP1-WT or PCBP1-K115R overexpression plasmids were transfected into the corresponding groups of cells. Solutions A and B were prepared in two sterile centrifuge tubes. Solution A (plasmid dilution): 4 μg of plasmid DNA was diluted with 250 μL of Opti-MEM or serum-free medium and gently mixed. Solution B (reagent dilution): 8 μL of Lipofectamine 2000 was diluted with 250 μL of Opti-MEM and incubated at room temperature for 5 minutes. After incubation, gently mix solutions A and B and let stand at room temperature for 20 minutes to form the DNA-liposome complex. Add 500 μL of the transfection complex dropwise evenly to each well of a six-well plate, gently shaking the plate to mix thoroughly. Return the plate to a 37°C, 5% CO2 incubator for incubation. After 6 hours, remove the culture medium containing the complex and replace it with 2 mL of fresh complete culture medium to reduce toxicity. Perform replicates for each group to ensure experimental reproducibility. 24 hours after transfection, treat the sodium lactate group with 5 mM sodium lactate for 24 hours to simulate a high lactate environment.

[0037] Cellular protein extraction: After aspirating the culture medium, cells were washed with pre-chilled PBS, followed by lysis on ice with a potent RIPA lysis buffer containing protease and phosphatase inhibitors. Cells were then scraped off using a cell scraper and repeatedly pipetted to ensure complete lysis. Finally, the lysis mixture was transferred to pre-chilled centrifuge tubes and centrifuged at 4°C and 12,000 rpm for 15 minutes. The supernatant was collected as the total protein solution, which was then quantified using methods such as BCA. The entire procedure must be performed at low temperature to maintain protein stability.

[0038] Western blotting: First, proteins were separated by molecular weight using SDS-PAGE electrophoresis. Then, the proteins on the gel were transferred to a PVDF membrane, and non-specific sites were blocked with 5% skim milk. The membrane was then incubated with specific primary antibody and enzyme-labeled secondary antibody in sequence. Finally, the target protein bands were visualized using ECL chemiluminescence reagent and the images were analyzed.

[0039] Fibrosis markers: Western blotting was used to detect the protein levels of α-SMA, Collagen I, and Fibronectin in cells.

[0040] Iron autophagy markers: Western blotting was used to detect the protein levels of NCOA4, ATG5, Beclin 1, and LC3 in cells.

[0041] 3. Experimental Results 3.1 PCBP1-K115R inhibits lactate-induced epithelial-mesenchymal transition in renal tubular epithelial cells. Figure 4 To obtain experimental results on the detection of α-SMA, Collagen I, and Fibronectin expression levels in cells by Western blotting, from... Figure 4 It can be seen that, compared with the PCBP1-WT group, PCBP1-K115R significantly inhibited sodium lactate-induced renal tubular epithelial-mesenchymal transition, as evidenced by a significant decrease in the expression levels of α-SMA, Collagen I, and Fibronectin.

[0042] 3.2 PCBP1-K115R significantly inhibited the expression of lactate-induced iron autophagy-related proteins in renal tubules. Figure 5 The results of the Western blotting experiment to detect the expression levels of NCOA4, ATG5, Beclin 1, and LC3 in cells were obtained from... Figure 5 It can be seen that, compared with the PCBP1-WT group, PCBP1-K115R significantly inhibited sodium lactate-induced ferrophagy in renal tubular epithelial cells, as evidenced by a significant decrease in the expression levels of NCOA4, ATG5, Beclin 1, and LC3.

[0043] Example 3 In vivo study on the reduction of renal fibrosis in mice by inhibiting PCBP1 lactation 1. Experimental Materials and Methods 1.1 Laboratory Animals Healthy male C57BL / 6 mice, 8 weeks old and weighing 20±2g, were purchased from Beijing Vital River Laboratory Animal Technology Co., Ltd. All animals were housed in an SPF-grade barrier environment with a standard 12-hour day / night cycle and free access to food and water.

[0044] 1.2 Experimental reagents Lentiviral construction and packaging: Overexpression plasmids: LV-PCBP1-WT (wild type), LV-PCBP1-K115R (K115→R, delactation-mimicking mutation), LV-PCBP1-K115T (K115→T, neutral amino acid mutation, negative control) and empty vector lentivirus (LV-Vector) were provided by Shanghai Genomics Co., Ltd.

[0045] Virus packaging: 293T cells (ATCC, CRL-3216) were co-transfected with overexpression plasmids and packaging plasmids (psPAX2, pMD2.G) using Lipofectamine 2000 (Invitrogen). Viral supernatant was collected after 48 hours and concentrated by ultracentrifugation (25000 rpm, 2 hours, 4℃). The titer was determined to be 1×10⁻⁶. 8 TU / mL (TCID) 50 (Preserve at -80℃).

[0046] 2. Experimental Methods 2.1 Establishing the UIRI mouse model Animal experimental design: Eight-week-old male C57BL / 6 mice were randomly divided into four groups (n=6) after one week of acclimatization: ① Sham group (LV-Vector group); ② UIRI+LV-PCBP1-WT group (LV-WT group); ③ UIRI+LV-PCBP1-K115R group (LV-115R); ④ UIRI+LV-PCBP1-K115T group (LV-115T). The constructed lentivirus was injected into the renal cortex at a viral load of 5 × 10⁻⁶. 5 The UIRI model was established one week after lentivirus injection. The UIRI model construction method was as follows: After anesthesia induction, a midline abdominal incision was made to expose the left renal pedicle. The pedicle was clamped with vascular clamps for 35 minutes, while maintaining core body temperature at 37°C throughout the ischemic period. Finally, the abdominal cavity and skin were sutured layer by layer. On day 10 post-surgery, a contralateral nephrectomy was performed; in the Sham group, only the abdominal cavity was opened and the left ureter was freed, without ligation. On day 11 post-modeling, the mice were sacrificed, and blood and kidney samples were collected for analysis.

[0047] 2.2 Sample Collection and Analysis: Serum and kidney tissue were collected on day 11 post-UIRI. Serum creatinine (SCr) and blood urea nitrogen (BUN) were measured. A portion of the kidney tissue was fixed for HE staining, Masson staining, and immunofluorescence staining (to detect α-SMA and Fibronectin).

[0048] 3. Experimental Results Figure 6 To verify the experimental results that local injection of LV-PCBP1-K115R significantly reduced renal fibrosis in mice, from... Figure 6 As shown in Figure A, HE staining revealed that LV-PCBP1-K115R significantly alleviated UIRI-induced kidney damage in mice, and Masson staining showed a significant reduction in collagen deposition in the renal interstitium of mice in the LV-PCBP1-K115R group. Figure 6As shown in Figure B, compared with the LV-PCBP1-WT group, the LV-PCBP1-K115R group mice showed a significant decrease in SCr and BUN. Figure 6 As shown in Figure C, immunofluorescence results revealed a significant reduction in the deposition of α-SMA and Fibronectin in the renal interstitium of mice in the LV-PCBP1-K115R group. These results indicate that local administration of LV-PCBP1-K115R to the kidneys can significantly improve UIRI-induced renal fibrosis in mice.

[0049] The above are merely preferred embodiments of the present invention and do not limit the patent scope of the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the patent protection scope of the present invention.

Claims

1. A biomarker that can be used for the auxiliary diagnosis of renal fibrosis, characterized in that: The biomarker is the lactated PCBP1 protein.

2. Application of lactated PCBP1 protein as a drug target for screening drugs to prevent, alleviate or treat renal fibrosis.

3. The application according to claim 2, characterized in that: The lactotreated PCBP1 protein is the PCBP1 protein with lactotreated position K115.

4. The application according to claim 2, characterized in that: The renal fibrosis disease is characterized by renal fibrosis with metabolic remodeling and chronic inflammation.

5. Application of substances that target and interfere with lactate modification of PCBP1 protein in the preparation of drugs for the prevention, relief or treatment of renal fibrosis.

6. The substance according to claim 5, characterized in that: The substance that targets and interferes with the lactate modification of the PCBP1 protein is the PCBP1-K115R mutant.

7. A drug, characterized in that: The drug is used to treat renal fibrosis, and the drug contains a substance that targets and interferes with lactate modification of PCBP1 protein.

8. The drug according to claim 7, characterized in that: The drug contains other pharmaceutically acceptable excipients or carriers.

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