Diagnostic marker and therapeutic target for psoriasis

Abstract

The invention relates to a psoriasis diagnosis marker and a psoriasis treatment target, and relates to the technical field of biological medicines. Through systematic analysis on the number, area and diameter of lymphatic vessels and VEGF-C expression of psoriasis skin and an established mouse model, the invention reveals that VEGF-C expression in psoriasis patient skin is up-regulated, the number, area and diameter of lymphatic vessels are obviously higher than those of healthy control, and the number expression of lymphatic vessels in a mouse recurrence model is further increased; and the VEGF-C expression is further improved. The research of the invention provides a new diagnostic marker and a potential therapeutic target for psoriasis, and provides a new direction and strategy for treating psoriasis or preventing relapse of psoriasis.

Description

A diagnostic biomarker and therapeutic target for psoriasis Technical Field

[0001] This invention relates to the field of biomedical technology, and in particular to a diagnostic biomarker and therapeutic target for psoriasis. Background Technology

[0002] Psoriasis is a chronic, relapsing inflammatory skin disease characterized by erythema, scaling, abnormal keratinization, and marked infiltrative inflammatory cell aggregation. Studies have shown that the pathogenesis and progression of psoriasis mainly involve abnormalities in the immune system and abnormal proliferation of keratinocytes. In contrast, the role of the vascular and lymphatic systems in psoriasis has been studied relatively little.

[0003] Current clinical immunohistochemical studies have found that, compared with non-lesioned skin, the expression of lymphatic markers PDPN and lymphatic growth factors VEGF-C and VEGF-D is significantly increased in psoriatic lesions. This suggests that lymphatic remodeling is closely related to the development of psoriatic lesions, but its specific role and regulatory mechanism in disease recurrence are unclear.

[0004] Vascular endothelial growth factor C (VEGF-C) is a major regulator of lymphangiogenesis, controlling lymphangiogenesis and function by binding to its receptor VEGFR-3. In chronic inflammatory skin models, activation of the VEGF-C / VEGFR-3 signaling pathway can significantly promote lymphatic vessel expansion, reduce inflammatory response, inhibit abnormal proliferation of keratinocytes and immune cell infiltration. However, its role in psoriasis, especially in the relapse process, has not been fully elucidated, and there are no reports of its use in the treatment of psoriasis or in the prevention of relapse. Summary of the Invention

[0005] The purpose of this invention is to address the above-mentioned problems by providing a diagnostic biomarker and therapeutic target for psoriasis.

[0006] The first aspect of this invention provides a diagnostic marker for psoriasis, employing the following technical solution:

[0007] A diagnostic biomarker for psoriasis, wherein the biomarker is vascular endothelial growth factor C (VEGF-C).

[0008] A second aspect of the present invention provides the use of the above-mentioned psoriasis diagnostic markers in the preparation of products for diagnosing psoriasis.

[0009] A third aspect of the present invention provides the application of the above-mentioned psoriasis diagnostic markers in the preparation of products for predicting the efficacy of psoriasis drugs.

[0010] Preferably, in the above application technology solution, the product includes a preparation, chip, or kit for detecting VEGF-C levels.

[0011] Preferably, in the above-mentioned application technology, the expression level of VEGF-C in the skin of psoriasis patients is increased.

[0012] A fourth aspect of the invention provides the use of VEGF-C as an inhibitory target in screening drugs for the treatment of psoriasis or the prevention of psoriasis recurrence.

[0013] Preferably, in the above application technology solution, the drug inhibits the expression level or activity of VEGF-C and / or improves the morphological or functional indicators of lymphatic vessels regulated by VEGF-C.

[0014] Preferably, in the above application technical solution, the lymphatic vessel morphology or functional indicators include the number, area, diameter, or Evans blue dye drainage efficiency of lymphatic vessels.

[0015] Preferably, in the above application technical solution, the screening method is as follows:

[0016] (a) To provide a psoriasis disease model system;

[0017] (b) Add the test compound to the model system;

[0018] (c) Detect the expression level or activity of VEGF-C in the model system, and / or detect morphological or functional indicators of lymphatic vessels regulated by VEGF-C;

[0019] (d) Compare the test results with the control group and select compounds that can downregulate VEGF-C expression or activity and / or improve lymphatic function as candidate drugs.

[0020] Preferably, in the above application technical solution, the psoriasis disease model system is an imiquimod (IMQ)-induced mouse psoriasis model or its relapse model.

[0021] In summary, this application includes at least one of the following beneficial technical effects:

[0022] This invention systematically analyzed the number, area, diameter, and VEGF-C expression of lymphatic vessels in psoriatic skin and an established mouse model. The results revealed that VEGF-C expression was upregulated in the skin of psoriasis patients, and the number, area, and diameter of lymphatic vessels were significantly higher than in healthy controls. Furthermore, in the mouse relapse model, the number and expression of lymphatic vessels were further increased, as was VEGF-C expression. This research provides a novel diagnostic biomarker and potential therapeutic target for psoriasis, offering a new direction and strategy for treating psoriasis or preventing its recurrence. Attached Figure Description

[0023] Figure 1 shows a comparison of the morphological observation of tissue sections and the measurement of VEGF-C expression levels between healthy controls and skin samples with psoriasis.

[0024] Figure 2 shows a schematic diagram and a general overview of the mouse model establishment process.

[0025] Figure 3 shows a comparison of the morphological observation of skin sections and the measurement of VEGF-C expression levels in the IMQ mouse model and the relapse model.

[0026] Figure 4 shows a comparison of lymphatic vessel morphology and lymphatic vessel function indicators between healthy controls and psoriasis skin samples.

[0027] Figure 5 shows the correlation analysis between the number of lymphatic vessels and the disease course and epidermal thickness.

[0028] Figure 6 shows HE staining images and statistical analysis of epidermal and dermal thickness in the IMQ and recurrence models;

[0029] Figure 7 shows the immunohistochemical staining and statistical analysis of the IMQ model and the relapse model LYVE1;

[0030] Figure 8 shows photographs of mice with local injections of Evans blue solution into their ears at different times.

[0031] Figure 9 shows the results of flow cytometry verification of donor whole spleen cells stained with fluorescent dye injected locally into the mouse ear 24 hours later, by taking the skin drainage lymph nodes. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments and accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. Modifications or equivalent substitutions made by those skilled in the art based on their understanding of the technical solutions of this invention, without departing from the spirit and scope of the invention, should all be covered within the protection scope of this invention.

[0033] Unless otherwise specified, the reagents, instruments and equipment used in the following examples are all commercially available products. Other specific conditions not specified shall be performed according to standard conditions or the manufacturer's recommendations.

[0034] Unless otherwise specified, the Chinese interpretations of chemical abbreviations used in this application shall be based on the generally accepted understanding within the industry.

[0035] I. Implementation Examples

[0036] Example 1

[0037] This embodiment verifies VEGF-C as a biomarker associated with psoriasis. Skin biopsy samples from different stages of psoriasis were collected, and the expression level of VEGF-C in the samples was detected. Then, a mouse psoriasis model and its relapse model were established, and the expression level of VEGF-C in the corresponding mouse skin samples was detected.

[0038] 1. Determination of VEGF-C expression level in psoriasis skin biopsy samples

[0039] Experimental materials: paraffin sections of psoriasis patients and healthy controls, VEGFC antibody (VEGF-CPolyclonal antibody, Wuhan Sanying, 22601-1-AP), immunohistochemistry kit (Wuhan Sanying, PK10009), PBS buffer, xylene, ethanol and other routine experimental consumables.

[0040] All paraffin sections of clinical skin tissue used in this application were obtained from the sample bank of the Pathology Laboratory of the Department of Dermatology, First Affiliated Hospital of Chongqing Medical University. Among them, the psoriasis samples were obtained from the skin lesions of patients with clinically and pathologically confirmed psoriasis, and the control samples were obtained from the normal skin tissue next to the mole obtained during the excision of benign moles. This application only uses delabeled samples for analysis. The sample processing involves embedding tissue sections in paraffin and the section thickness is 5μm.

[0041] Experimental methods: The immunohistochemical experimental steps are as follows:

[0042] 1) Dewaxing paraffin sections to water: First, place the sections in xylene for 20 minutes twice, then place them in 100%, 95%, 80% and 60% ethanol for 5 minutes each time, then rinse with distilled water 3 times for 1 minute each time, and then wash with PBS 3 times for 5 minutes each time.

[0043] 2) Antigen retrieval: After adding Tris-EDTA retrieval solution, place the slide in a microwave oven and retrieval twice on medium heat for 5 minutes each time. After retrieval, allow it to cool naturally in the retrieval solution, and then wash it three times with PBS for 5 minutes each time.

[0044] 3) Inactivation: Use the endogenous peroxidase inactivation reagent provided in the kit, 37℃, 15min, after which the blocking is complete. Wash with PBS 3 times, 5min each time.

[0045] 4) Blocking: Block the tissue with blocking buffer at 37°C for 60 minutes, drain the liquid from the slide, and blot the remaining liquid around the tissue section with absorbent paper.

[0046] 5) Incubate primary antibody: Dilute the primary antibody (rabbit primary antibody) with appropriate primary antibody dilution buffer, incubate overnight at 4°C, and wash 3 times with PBS for 5 minutes each time.

[0047] 6) Incubation with secondary antibody: Add anti-rabbit HRP-labeled polymer, incubate at 37°C for 60 minutes, wash with PBS 3 times, 5 minutes each time.

[0048] 7) DAB color development: Prepare the DAB stock solution and DAB dilution solution in advance at a ratio of 1:20, mix well, and store in the dark. Add the prepared DAB working solution as the color developer, and control the reaction time under a microscope. Wash three times with PBS, 5 minutes each time.

[0049] 8) Counterstain with hematoxylin for 15 seconds. Wash three times with PBS, 5 minutes each time.

[0050] 9) Dehydrate with alcohol at each stage (60-100%) for 5 minutes each. After removal, place in xylene for 5 minutes, twice. Seal with mounting adhesive and observe under a microscope.

[0051] Results: The imaging images and detection results of the healthy group (HC) and the psoriasis group (PS) are shown in Figure 1.

[0052] Morphological observation of tissue sections revealed that the HC group had intact skin tissue structure, clear boundary between the epidermis and dermis, uniform stratum corneum thickness, and regular cell arrangement with uniformly stained nuclei under high magnification. In contrast, the PS group showed significant epidermal thickening, stratum corneum accumulation, and disordered dermal structure. Under high magnification, the cells were arranged haphazardly with deeply stained nuclei, indicating inflammatory cell infiltration.

[0053] The quantitative analysis of VEGFC expression showed that the fluorescence intensity (representing VEGFC expression level) in the PS group was significantly higher than that in the HC group (P<0.001), and the VEGFC mRNA expression level in the PS group was about 3 times that in the HC group (P<0.0001).

[0054] This demonstrates that the expression level of VEGF-C in the skin of psoriasis patients is increased, indicating that it can serve as a diagnostic marker for psoriasis.

[0055] 2. Mouse model validation

[0056] Laboratory mice: C57BL / 6J male mice, 6-8 weeks old, weighing 18-22g, obtained from the Animal Center of Chongqing Medical University.

[0057] Experimental materials: IMQ cream (3g:0.15g, manufacturer: Mingxinlidi), other experimental materials are the same as in 1.

[0058] Methods for establishing mouse models:

[0059] IMQ-induced model: 10 mg of IMQ cream was applied topically to each ear of mice daily for 7 consecutive days to serve as a psoriasis model (DAY7).

[0060] Relapse model: After the first IMQ induction, the mouse rested for 2 weeks until the appearance was normal (DAY20). IMQ cream was applied again until DAY27 to serve as the relapse model. The flowchart and macroscopic diagram of the mouse model establishment are shown in Figure 2.

[0061] Control group: Age-matched mice were treated with petroleum jelly cream.

[0062] Sample collection: Mice were euthanized at the end of the experiment, and skin samples were collected and immediately fixed in 4% paraformaldehyde for 24 hours; then embedded in paraffin and sectioned to 5μm.

[0063] Experimental method: Immunohistochemistry was used, and the specific steps were the same as in 1.

[0064] Results: The imaging photographs of mice in each group and the results of VEGF-C quantitative analysis are shown in Figure 3.

[0065] Morphological observation of tissue sections revealed that in the psoriasis model (DAY7), the mouse ear skin exhibited epidermal thickening, stratum corneum disorder, and inflammatory cell infiltration in the dermis, consistent with the characteristics of the acute phase of psoriasis. In the recovery phase (DAY20), the mouse skin structure basically returned to normal, the epidermal thickness was close to normal, and the number of inflammatory cells decreased, but it did not fully recover to the initial state. In the relapse model (DAY27), the mouse ear skin again showed obvious epidermal hyperplasia, stratum corneum abnormalities, and inflammatory cell aggregation in the dermis, indicating that the model had successfully relapsed.

[0066] The quantitative analysis of VEGFC expression showed that in the psoriasis model (DAY7), the fluorescence intensity and mRNA expression of VEGFC were significantly increased (P<0.01), indicating the activation of the inflammatory response. In the recovery period (DAY20), VEGFC expression decreased to near baseline levels (P>0.05), consistent with the trend of tissue morphology recovery. In the relapse model (DAY27), VEGFC expression increased significantly again (P<0.001), and was even higher than in the initial induction period, which was associated with the aggravation of tissue damage in the relapse period.

[0067] This demonstrates that VEGF-C is not only associated with the acute phase of psoriasis, but its sustained high expression is also closely related to the disease relapse process, reinforcing its potential as a marker of relapse risk.

[0068] Example 2

[0069] This embodiment verifies the association between high VEGF-C expression and lymphatic vessel dysfunction.

[0070] 1. Analysis of lymphatic vessel morphology and function in psoriasis skin biopsy samples

[0071] Experimental materials: paraffin sections of psoriasis patients and healthy controls, PDPN antibody (mAb Podoplanin anti-humanAbcam AB236529), immunohistochemistry kit (Wuhan Sanying, PK10009), PBS buffer, xylene, ethanol and other routine experimental consumables.

[0072] Experimental method: PDPN immunohistochemical labeling of lymphatic vessels. The experimental procedure is the same as in Example 1, only the antibody needs to be changed, which will not be repeated here.

[0073] Experimental results: The number, area and diameter of lymphatic vessels were counted using a slide scanner and image analysis software; Figure 4 shows the schematic diagram of PDPN immunohistochemical staining and the statistical analysis of lymphatic vessel functional indicators; Figure 5 shows the correlation analysis between the number of lymphatic vessels and the disease course and epidermal thickness.

[0074] As shown in Figure 4, the epidermal structure of the healthy group (HC) skin samples was intact, and the dermal lymphatic vessels (PDPN positive marker, brown) were sparsely distributed and regularly shaped, with a smaller number of lymphatic vessels. The epidermis of the psoriasis group (PS) skin samples was significantly thickened, and the number of dermal lymphatic vessels was significantly increased, densely distributed, and expanded, with some areas showing clustered proliferation of lymphatic vessels. As shown in the quantitative analysis in Figure 4, the number of lymphatic vessels (LV / HPF) in the PS group was significantly higher than that in the HC group (P < 0.0001), indicating active lymphangiogenesis in psoriasis. The area of ​​lymphatic vessels (Area of ​​LV) in the PS group was greater than that in the HC group (P < 0.05), indicating lymphatic vessel dilation. The major axis of lymphatic vessels in the PS group was longer than that in the HC group (P < 0.05), further confirming the changes in lymphatic vessel structure.

[0075] As shown in the correlation analysis chart in Figure 5, the number of lymphatic vessels is positively correlated with epidermal thickness (R=0.61, P=0.02). The thicker the epidermis, the more lymphatic vessels there are. Psoriatic epidermal hyperplasia may stimulate lymphatic vessel hyperplasia by releasing pro-lymphangiogenic factors (such as VEGFC). Furthermore, the number of lymphatic vessels is positively correlated with the course of the disease (R=0.48, P=0.085, close to significant), suggesting that lymphatic vessel hyperplasia may gradually worsen as the disease progresses.

[0076] 2. Analysis of lymphatic vessel morphology and function in a mouse model of psoriasis

[0077] The establishment of the mouse model and sample collection were the same as in Example 1.

[0078] Experimental materials: IMQ cream (3g:0.15g, manufacturer: Mingxinlidi), LYVE1 antibody (Rabbit anti-mouseLYVE1), and other experimental materials as described in 1.

[0079] Experimental method: Lymphatic vessels were labeled with LYVE1 immunohistochemistry, and the immunohistochemical experimental procedure was the same as in Example 1.

[0080] Experimental results: The number, area and diameter of lymphatic vessels were counted using a slide scanner and image analysis software. The HE staining images and epidermal and dermal thickness statistics of the IMQ model and relapse model are shown in Figure 6. The immunohistochemical staining images and statistical analysis of LYVE1 in the IMQ model and relapse model are shown in Figure 7.

[0081] As shown in Figure 6, the epidermis of Day 0 (healthy control group) was thin and structurally intact, with neatly arranged dermal cells and no inflammatory cell infiltration. In Day 7 (psoriasis model) mice, the epidermis was significantly thickened (acanthosis), the stratum corneum was thickened and irregular, and a large number of inflammatory cells were visible in the dermis, consistent with typical psoriasis characteristics. In Day 20 (recovery period) mice, the epidermal thickness decreased, approaching normal levels, inflammatory cells decreased, and the tissue structure tended to be normal. However, in the relapse model mice, the epidermis thickened again, and inflammatory cells re-aggregated, indicating disease relapse. The analysis in Figure 6 shows that the epidermal thickness increased significantly on Day 7 and Day 27 (P<0.01), and while there was some recovery on Day 20, it was not completely normal. The dermal thickness increased significantly on Day 7 (P < 0.001), and remained above baseline on Day 20 and Day 27, reflecting the continued impact of dermal inflammation and edema.

[0082] As shown in the histological diagram in Figure 7, the lymphatic vessels in Day 0 are sparsely distributed, regularly shaped, and small in area and diameter. The number of lymphatic vessels in the psoriasis model is significantly increased, and their area and diameter are enlarged, possibly due to inflammation leading to lymphatic vessel dilation and new formation. The area and diameter of lymphatic vessels in the recovery period have decreased, but are still higher than the baseline, suggesting that the lymphatic vessel function gradually returns to normal during the recovery period but has not fully recovered. The lymphatic vessels in the relapse model dilate significantly again and increase in number, consistent with the aggravation of inflammation during the relapse period.

[0083] This demonstrates that the IMQ-induced psoriasis model successfully simulates the epidermal hyperplasia, inflammatory infiltration, and lymphatic changes in human psoriasis. The relapse model further validates the reversibility and recurrence of the disease. Changes in lymphatic vessels are closely related to disease activity and may serve as a potential indicator for assessing the severity of psoriasis and the effectiveness of treatment.

[0084] 3. Lymphatic vessel function experiments in IMQ and relapse models

[0085] The lymphatic vessel function experiment, including Evans blue dye drainage and in vitro cell staining drainage, was used to detect the ability of local tissue lymphatic vessels in mouse ears to drain dye and cells.

[0086] Experimental materials: Evans Blue dye (Sigma, catalog number E2129), fluorescently labeled whole spleen cells (CellTrace™ Far Red Cell Proliferation Kit for flow cytometry, manufacturer ThermoFisher, catalog number C34564), microsyringe (0.26mm needle tip), flow cytometer, PBS and other routine experimental consumables.

[0087] Experimental methods:

[0088] Evans blue dye lymphatic drainage experiment: 1% Evans blue dye solution was prepared in PBS; 3 μL of Evans blue was injected locally into the skin behind the ear of mice; photographs were taken at 0, 6 and 24 hours; mice were sacrificed after 24 hours and ear skin was collected to detect the remaining dye.

[0089] In vitro cell drainage experiment: Whole spleen cells were prepared from the spleen of healthy mice, ground, cleaved, and stained with CellTracker dye for 20 min at 37℃. After staining, the cells were washed twice with PBS. A suspension of labeled cells (1×10^6 cells / 5ul) was injected locally into the skin behind the ear. After 24 hours, the drainage lymph nodes from the ear skin were collected and a single-cell suspension was prepared. The number of labeled cells was detected by flow cytometry to assess the drainage capacity of lymphatic vessels. The effect of inflammation on lymphatic vessel cell drainage was analyzed by comparing the IMQ model, the relapse model, and the control group.

[0090] Data analysis: The distribution of Evans blue dye on the ear skin was recorded by camera. The remaining Evans blue dye in the ear was extracted with formamide and then detected by ELISA reader. The percentage and number of labeled cells in the lymph nodes were counted. The changes in lymphatic vessel function were compared by combining the IMQ model (DAY7) and the recurrence model (DAY27) to determine the impact of inflammation and recurrence on lymphatic drainage function.

[0091] Experimental results: Figure 8 shows photographs of mice injected with Evans blue solution at different times. Figure 9 shows the results of flow cytometry verification of lymph nodes drained from the skin 24 hours after local injection of donor whole spleen cells stained with fluorescent dye into the mouse ear.

[0092] As shown in Figure 8, in the control group, Evans blue leakage was minimal at 0, 6, and 24 hours after injection, indicating low vascular permeability in normal skin. In the psoriasis model, Evans blue leakage began at 0 hours, increased significantly at 6 hours, and the ears turned distinctly blue, indicating increased vascular permeability. Leakage continued at 24 hours, with the color slightly deepening or remaining the same, reflecting the continued impact of inflammation on blood vessels. In the recovery phase, Evans blue leakage was minimal at 0 hours, and decreased at 6 and 24 hours compared to Day 7, but still higher than Day 0, indicating that vascular permeability gradually recovered but was not completely normal. In the relapse model, Evans blue leakage began at 0 hours, and increased significantly again at 6 and 24 hours, similar to Day 7, indicating that vascular permeability increased again during the relapse phase.

[0093] As shown in Figure 9, the upper part of the figure shows a scatter plot of flow cytometry. The horizontal axis represents the fluorescence intensity of APC-Far red, and the vertical axis represents FSC-H (reflecting cell size). A polygonal gating region is defined in the figure to delineate the Far red-positive (Farred+) cell population, which are the homing or migrating cells of the injected fluorescently labeled donor spleen cells in the draining lymph nodes. The bar chart below shows the number of Far red+ cells in the postauricular lymph nodes (sLN) at four time points: Day 0, Day 7, Day 20, and Day 27.

[0094] The Evans blue leakage experiment visually demonstrated the dynamic changes in vascular permeability in IMQ-induced psoriasis models and relapse models. In the IMQ model (DAY7), the skin of mice showed decreased tissue Evans blue dye drainage and increased leakage. In the relapse model (DAY27), the decreased tissue Evans blue dye drainage and increased leakage were further increased, indicating that vascular permeability was significantly increased in the acute and relapse phases of psoriasis, and although it decreased somewhat in the recovery phase, it was not completely normal. In the IMQ model (DAY7), the skin of mice showed increased cell drainage, and in the relapse model (DAY27), the increased tissue drainage to cells was further increased. This indicates that there is continuous functional remodeling of lymphatic vessels under psoriatic inflammation. Combined with the observed increase in the number and area of ​​lymphatic vessels, it suggests that these dilated lymphatic vessels are accompanied by damaged lymphatic vessels, exhibiting a "dilated but low-quality" functional state, which may lead to the retention of inflammatory mediators in the tissue, providing a microenvironmental basis for inflammation maintenance and relapse.

[0095] As shown in Figure 9, the number of Far Red+ cells was relatively low in the control group; the number of Far Red+ cells increased significantly in the psoriasis model, indicating that in the acute phase of IMQ-induced psoriasis, the migration or homing of donor spleen cells to the skin drainage lymph nodes was enhanced; the number of Far Red+ cells decreased in the recovery phase, but was still higher than the baseline level on Day 0, suggesting that immune cell migration gradually recovered during the recovery phase, but was not completely normalized; the number of Far Red+ cells increased significantly again in the relapse model, similar to the level on Day 7, indicating that immune cell migration was active again during the relapse phase, which is related to disease relapse.

[0096] Therefore, the Far Red Celltracer experiment further verified the functional changes from the perspective of cell migration. In DAY7 and DAY27, the number of Far Red+ cells in the lymph nodes increased significantly, suggesting that the lymphatic vessels have enhanced ability to migrate immune cells. Physiologically, this helps to transmit peripheral inflammatory signals to the lymph nodes and initiate an immune response. However, in psoriasis, the continuously enhanced immune cell backflow may exacerbate the activation of effector T cell circulation, promote inflammation amplification and recurrence.

[0097] Combined with Example 1, this result establishes a causal chain of "VEGF-C high expression → lymphatic vessel morphological abnormalities / functional disorders → disease occurrence and recurrence", thus proving that intervention with VEGF-C is a reasonable target for regulating lymphatic vessel function and treating diseases.

[0098] Example 3

[0099] Based on the results obtained in Examples 1 and 2, this example provides a method for screening drugs for treating psoriasis or preventing psoriasis recurrence, comprising the following steps:

[0100] (a) Using the psoriasis disease model system as provided in Example 1;

[0101] (b) Applying the test compound (such as a small molecule compound library, antibody fragment, etc.) locally or systematically to model mice;

[0102] (c) Detect the expression level or activity of VEGF-C in the model system, and / or detect morphological or functional indicators of lymphatic vessels regulated by VEGF-C, such as detecting the protein expression level of VEGF-C in tissues by IHC or Western blotting, or detecting the VEGFC mRNA level by qPCR. Simultaneously, LYVE1 staining can be performed on tissue sections to analyze changes in the number and area of ​​lymphatic vessels;

[0103] (d) Compare the test results with the control group and select compounds that can downregulate VEGF-C expression or activity and / or improve lymphatic function as candidate drugs.

[0104] In summary, this invention, through a systematic analysis of the number, area, diameter, and VEGF-C expression of lymphatic vessels in psoriatic skin and an established mouse model, revealed that VEGF-C expression is upregulated in the skin of psoriasis patients, and the number, area, and diameter of lymphatic vessels are significantly higher than in healthy controls. Furthermore, in the mouse relapse model, the number and expression of lymphatic vessels are further increased, as is VEGF-C expression. This research provides a novel diagnostic biomarker and potential therapeutic target for psoriasis, offering a new direction and strategy for treating psoriasis or preventing its recurrence.

Claims

1. A diagnostic marker for psoriasis, characterized in that: The biomarker is vascular endothelial growth factor C (VEGF-C).

2. The application of the psoriasis diagnostic marker according to claim 1 in the preparation of products for diagnosing psoriasis.

3. The application of the psoriasis diagnostic markers according to claim 1 in the preparation of products for predicting the efficacy of psoriasis drugs.

4. The application according to claim 2 or 3, characterized in that: The products include formulations, chips, or kits containing the detection of VEGF-C levels.

5. The application according to claim 2, characterized in that: The expression level of VEGF-C is increased in the skin of patients with psoriasis.

6. The application of VEGF-C as an inhibitory target in screening drugs for the treatment of psoriasis or the prevention of psoriasis recurrence.

7. The application according to claim 6, characterized in that: The drug inhibits the expression level or activity of VEGF-C and / or improves the morphological or functional indicators of lymphatic vessels regulated by VEGF-C.

8. The application according to claim 7, characterized in that: The lymphatic vessel morphology or functional indicators include the number, area, diameter, or Evans blue dye drainage efficiency of lymphatic vessels.

9. The application according to claim 6, characterized in that: The screening method is as follows: (a) providing a psoriasis disease model system; (b) adding the test compound to the model system; (c) detecting the expression level or activity of VEGF-C in the model system, and / or detecting lymphatic vessel morphology or functional indicators regulated by VEGF-C; (d) comparing the detection results with the control group, and selecting compounds that can downregulate VEGF-C expression or activity and / or improve lymphatic vessel function as candidate drugs.

10. The application according to claim 9, characterized in that: The psoriasis disease model system is an imiquimod (IMQ)-induced mouse psoriasis model or its relapse model.

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