Transcriptome Analysis and Emerging Driver Identification of CD8+ T Cells in Patients with Vitiligo

Combining network pharmacology, molecular docking, molecular dynamics simulation, and experimental verification to examine the efficacy and immunoregulation mechanism of FHB granules on vitiligo

Background

Fufang Honghua Buji (FHB) granules, have proven efficacy against vitiligo in long-term clinical practice. However, its major active chemical components and molecular mechanisms of action remain unknown. The purpose of this study was to confirm the molecular mechanism of FHB's therapeutic effect on vitiligo utilizing network pharmacology, molecular docking, and molecular dynamics simulation prediction, as well as experimental verification.

Methods

Traditional Chinese Medicine Systems Pharmacology (TCMSP) and HERB databases were used to obtain the chemical composition and action targets of FHB. Online Mendelian Inheritance in Man (OMIM), DrugBank, DisGeNET, GeneCards, and Therapeutic Target Database (TTD) databases were applied to screen for vitiligo-related targets. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were performed through the Matascape database. Molecular docking and dynamics simulation methods were for the analysis of the binding sites and binding energies between the FHB's active components and the targets. Finally, a vitiligo mouse model was created, and the therapeutic effect and molecular mechanism of action of FHB were validated using enzyme linked immunosorbent assay (ELISA), western blot (WB), and quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Additionally, hematoxylin-eosin staining (HE) and blood biochemical assays were conducted to assess the biosafety of FHB.

Result

The screening of chemical composition and targets suggested that 94 genetic targets of FHB were associated with vitiligo. The bioinformatics analysis suggested that luteolin, quercetin, and wogonin may be major active components, and nuclear factor-kappa B p65 subunit (RELA), signal transducer, and activator of transcription (STAT) 3 and RAC-alpha serine/threonine-protein kinase (AKT) 1 may be potential targets of FHB-vitiligo therapy. Molecular docking and dynamics simulation further demonstrated that luteolin, quercetin, and wogonin all bound best to STAT3. Through experimental verification, FHB has been demonstrated to alleviate the pathogenic characteristics of vitiligo mice, suppress the JAK-STAT signaling pathway, reduce inflammation, and increase melanogenesis. The in vivo safety evaluation experiments also demonstrated the non-toxicity of FHB.

Conclusions

FHB exerts anti-inflammatory and melanogenesis-promoting effects via the effect of multi-component on multi-target, among which the JAK-STAT pathway is a validated FHB-vitiligo target, providing new ideas and clues for the development of vitiligo therapy.

Occludin Promotes Adhesion of CD8+ T Cells and Melanocytes in Vitiligo via the HIF-1α Signaling Pathway

Loss of melanocytes induced by activated CD8+ T cells is the pathological hallmark of vitiligo. Melanocyte-specific CD8+ T cells are recruited to the skin via chemokines, thereby releasing perforin, granzyme, and other cytotoxic substances that destroy the melanocytes. However, the mechanism of CD8+ T cells to adhere to melanocytes is unknown. Previous transcriptome sequencing results published by our group showed that the occluding (OCLN) gene was significantly upregulated in CD8+ T cells from skin lesions of vitiligo. Occludin is a crucial component of the tight junction between cells; in cells without tight junction, occludin mediates the adhesion of two cells in the form of a self-ligand. This study demonstrated that OCLN gene expression was elevated in the CD8+ T cells of vitiligo patients, and occludin mediates the adherence of CD8+ T cells to melanocytes. Besides, pathological changes in vitiligo skin lesions reveal that CD8+ T cells continuously persist in the skin lesions, which is related to the persistence of the disease. In this regard, we found that fibroblasts from vitiligo patients significantly express occludin, which may participate in the continuous retention of CD8+ T cells in the skin lesions. The pathogenesis of vitiligo is closely related to oxidative stress, and our data suggest that overexpression of hypoxia-inducible factor-1α (HIF-1α) increases the expression of occludin. Besides, ChIP-qPCR of CD8+ T cells revealed that HIF-1α directly binds to the OCLN promoter. Thus, occludin upregulation promotes the adhesion of CD8+ T cells and melanocytes via the HIF-1α signaling pathway. Our study results suggested a critical role for OCLN in the occurrence, progression, and maintenance of vitiligo. Therefore, inhibiting the expression of OCLN gene may be a potential targeted treatment strategy.

Successful Treatment of Vitiligo with Cold Atmospheric Plasma‒Activated Hydrogel

Vitiligo shows insufficient response to current therapies largely owing to T-lymphocyte dysfunction, abnormal inflammatory activation, and excessive oxidative stress in lesions. Cold atmospheric plasma (CAP) possesses pleiotropic antioxidant and anti-inflammatory properties and may offer an improvement to current treatment options. In this study, the efficacy and safety of CAP were investigated in a mouse model of vitiligo and a randomized and controlled trial of patients with active focal vitiligo. Skin biopsies showed that topical treatment of vitiligo-like lesions on mouse dorsal skin by CAP restored the distribution of melanin. In addition, CAP treatment reduced the infiltration of CD11c+ dendritic cells, CD3+ T cells, and CD8+ T cells; inhibited the release of CXCL10 and cytokine IFN-γ; and enhanced cellular resistance to oxidative stress and excessive immune response by enhancing the expression of the transcription factor NRF2 and attenuating the activity of inducible nitric oxide synthase. In a randomized and controlled trial, CAP treatment achieved partial and complete repigmentation in 80% and 20% of vitiligo lesions, respectively, without hyperpigmentation in surrounding areas or other adverse events during the treatment period and its follow-up period. In conclusion, CAP offers a promising option for the management of vitiligo.

Myron Gordon Award paper: Microbes, T-cell diversity and pigmentation

Melanocytes are static, minimally proliferative cells. This leaves them vulnerable in vitiligo. Yet upon malignant transformation, they form vicious tumors. This profound switch in physiology is accompanied by genetic change and is driven by environmental factors. If UV exposure in younger years supports malignant transformation and melanoma formation, it can likewise impart mutations on melanocytes that reduce their viability, to initiate vitiligo. A wide variety of microbes can influence these diametrically opposed outcomes before either disease takes hold. These microbes are vehicles of change that we are only beginning to study. Once a genetic modification occurs, there is a wide variety of immune cells ready to respond. Though it does not act alone, the T cell is among the most decisive responders in this process. The same biochemical process that offered the skin protection by producing melanin can become an Achilles heel for the cell when the T cells target melanosomal enzymes or, on occasion, neoantigens. T cells are precise, determined, and consequential when they strike. Here, we probe the relationship between the microbiome and its metabolites, epithelial integrity, and the activation of T cells that target benign and malignant melanocytes in vitiligo and melanoma.

Differentially expressed microRNAs in peripheral blood mononuclear cells of non-segmental vitiligo and their clinical significance

Background

Vitiligo is a frequent acquired depigmentation skin disease due to a loss of melanocytes. This study sought to characterize the expression pattern of microRNA (miRNA) in the peripheral blood mononuclear cells (PBMCs) of non‐segmental vitiligo (NSV) patients. We also screened for molecular markers that can be used to evaluate the clinical stages of NSV.

Methods

The miRNA expression profile in the PBMCs of four patients with progressive NSV and four healthy controls was determined using high‐throughput RNA sequencing. The divergently expressed miRNA was verified via qRT‐PCR in 26 progression, 26 stable NSV, and 26 healthy controls.

Results

Our findings posited that 323 miRNAs were differentially expressed in the PBMCs of NSV patients. The top 10 up‐regulated miRNAs in patients were hsa‐miR‐335‐5p, hsa‐miR‐20a‐5p, hsa‐miR‐514a‐3p, hsa‐miR‐144‐5p, hsa‐miR‐450b‐5p, hsa‐miR‐369‐3p, hsa‐miR‐101‐3p, hsa‐miR‐142‐5p, hsa‐miR‐19b‐3p, and hsa‐miR‐340‐5p. The top 10 down‐regulated miRNAs in patients were hsa‐miR‐4443, hsa‐miR‐1248, hsa‐miR‐6859‐3p, hsa‐miR‐668‐3p, hsa‐miR‐7704, hsa‐miR‐323a‐5p, hsa‐miR‐1237‐3p, hsa‐miR‐3127‐3p, hsa‐miR‐6735‐3p, and hsa‐miR‐127‐3p. The expressions of hsa‐miR‐20a‐5p in PBMCs of progressive and stable NSV were remarkably elevated relative to the healthy controls. In the characteristics curve analysis of hsa‐miR‐20a‐5p for differentiating progressive and stable NSV from normal subjects in PBMCs, the area under curve (AUC) was 0.92 and 0.81. Compared with patients in stable NSV, the hsa‐miR‐20a‐5p was markedly increased in PBMCs of progressive NSV patients, and the AUC was 0.81.

Conclusion

Our results showed that divergently expressed miRNAs contribute to the pathogenesis of NSV and that hsa‐miR‐20a‐5p can be applied as a biosignature for stage assessment in PBMCs of patients with NSV.

Increased Serum Levels of IFN-γ, IL-1β, and IL-6 in Patients with Alopecia Areata and Nonsegmental Vitiligo

Alopecia areata (AA) and vitiligo are both common skin diseases of autoimmune origin. Both alopecia areata and vitiligo have shown to be affected by oxidative stress. The present work is aimed at evaluating and comparing the serum proinflammatory cytokine levels in AA and nonsegmental vitiligo (NSV). A cross-sectional study was conducted of 33 patients with AA, 30 patients with NSV, and 30 healthy controls. Serum levels of interferon γ (IFN-γ), interleukin- (IL-) 1β, and IL-6 were determined quantitatively by ELISA method. Our analysis identified a signature of oxidative stress associated with AA and NSV, characterized by elevated levels of IFN-γ (AA: p = 0.007283; NSV: p = 0.038467), IL-1β (AA; NSV: p ≤ 0.001), and IL-6 (AA; NSV: p ≤ 0.001). IL-6 was also significantly increased in NSV patients in comparison with AA patients (p = 0.004485). Our results supported the hypothesis that oxidative stress may play a significant role in promoting and amplifying the inflammatory process both in AA and vitiligo. The complex understanding of both disease etiopathogenesis involves interrelationships between oxidative stress and autoimmunity. The clinical study registration number is RNN/266/16/KE.

VIRdb: a comprehensive database for interactive analysis of genes/proteins involved in the pathogenesis of vitiligo

Vitiligo is a chronic asymptomatic disorder affecting melanocytes from the basal layer of the epidermis which leads to a patchy loss of skin color. Even though it is one of the neglected disease conditions, people suffering from vitiligo are more prone to psychological disorders. As of now, various studies have been done in order to project auto-immune implications as the root cause. To understand the complexity of vitiligo, we propose the Vitiligo Information Resource (VIRdb) that integrates both the drug-target and systems approach to produce a comprehensive repository entirely devoted to vitiligo, along with curated information at both protein level and gene level along with potential therapeutics leads. These 25,041 natural compounds are curated from Natural Product Activity and Species Source Database. VIRdb is an attempt to accelerate the drug discovery process and laboratory trials for vitiligo through the computationally derived potential drugs. It is an exhaustive resource consisting of 129 differentially expressed genes, which are validated through gene ontology and pathway enrichment analysis. We also report 22 genes through enrichment analysis which are involved in the regulation of epithelial cell differentiation. At the protein level, 40 curated protein target molecules along with their natural hits that are derived through virtual screening. We also demonstrate the utility of the VIRdb by exploring the Protein-Protein Interaction Network and Gene-Gene Interaction Network of the target proteins and differentially expressed genes. For maintaining the quality and standard of the data in the VIRdb, the gold standard in bioinformatics toolkits like Cytoscape, Schrödinger's GLIDE, along with the server installation of MATLAB, are used for generating results. VIRdb can be accessed through "http://www.vitiligoinfores.com/".