PINK1 in normal human melanocytes: first identification and its effects on H2 O2 -induced oxidative damage

The underestimated role of mitochondria in vitiligo: From oxidative stress to inflammation and cell death

Vitiligo is an acquired depigmentary disorder characterized by the depletion of melanocytes in the skin. Mitochondria shoulder multiple functions in cells, such as production of ATP, maintenance of redox balance, initiation of inflammation and regulation of cell death. Increasing evidence has implicated the involvement of mitochondria in the pathogenesis of vitiligo. Mitochondria alteration will cause the abnormalities of mitochondria functions mentioned above, ultimately leading to melanocyte loss through various cell death modes. Nuclear factor erythroid 2-related factor 2 (Nrf2) plays a critical role in mitochondrial homeostasis, and the downregulation of Nrf2 in vitiligo may correlate with mitochondria damage, making both mitochondria and Nrf2 promising targets in treatment of vitiligo. In this review, we aim to discuss the alterations of mitochondria and its role in the pathogenesis of vitiligo.

Exploring the mechanism of Liuwei Dihuang formula for promoting melanin synthesis in juvenile zebrafish based on network pharmacology and molecular docking

Background

Vitiligo stands as a challenging skin disorder with limited treatment options available. LiuWei DiHuang formula (LDF), a renowned Traditional Chinese medicine, has exhibited promising results in treating vitiligo over an extended period. However, the precise underlying mechanism of its action remains elusive.

Methods

Employing a comprehensive network pharmacology approach, this study identified active compounds and their corresponding targets within LDF, while also pinpointing vitiligo-associated targets sourced from the TCMSP database, OMIM, DisGenNET, and Genecards. A network was established to illustrate the connections between active compounds and targets, alongside a protein-protein interaction network. Further analyses, encompassing Gene Ontology (GO) function and KEGG pathway enrichment, were conducted using the DAVID platform. Molecular docking simulations were performed utilizing AutoDockTools and AutoDockVina software. To validate the outcomes of the systematic pharmacological investigation, experiments were conducted using juvenile zebrafish.

Results

The collective effort of the network pharmacology approach yielded a compilation of 41 compounds and 192 targets. Molecular docking simulations notably revealed the lowest binding energies for CAT-quercetin and CAT-Kaempferol interactions. The utilization of juvenile zebrafish experiments highlighted a significant increase in melanocyte count following methoxsalen and LDF treatment. Notably, LDF prominently augmented the expression levels of proteins related to melanogenesis. Additionally, LDF showcased the capacity to enhance CAT and SOD levels while concurrently reducing ROS and MDA activity. In contrast to the model group, substantial increases in protein and mRNA levels of Nrf2 and HO-1 were observed in response to LDF treatment (P < 0.05).

Conclusion

Through a meticulous network pharmacology approach, this study successfully predicted active components and potential targets associated with LDF's application in vitiligo treatment. The therapeutic effectiveness of LDF against vitiligo is postulated to stem from its regulation of oxidative stress factors and the Nrf2/HO-1 pathway.

Mitophagy and immune infiltration in vitiligo: evidence from bioinformatics analysis

Background

Vitiligo is an acquired, autoimmune, depigmented skin disease with unclear pathogenesis. Mitochondrial dysfunction contributes significantly to vitiligo, and mitophagy is vital for removing damaged mitochondria. Herein, using bioinformatic analysis, we sought to determine the possible role of mitophagy-associated genes in vitiligo and immune infiltration.

Methods

Microarrays GSE53146 and GSE75819 were used to identify differentially expressed genes (DEGs) in vitiligo. By crossing vitiligo DEGs with mitophagy-related genes, the mitophagy-related DEGs were identified. Functional enrichment and protein-protein intersection (PPI) analyses were conducted. Then, the hub genes were identified using two machine algorithms, and receiver operating characteristic (ROC) curves were generated. Next, the immune infiltration and its connection with hub genes in vitiligo were investigated. Finally, the Regnetwork database and NetworkAnalyst were used to predict the upstream transcriptional factors (TFs), microRNAs (miRNAs), and the protein-compound network.

Results

A total of 24 mitophagy-related genes were screened. Then, five mitophagy hub genes (GABARAPL2, SP1, USP8, RELA, and TBC1D17) were identified using two machine learning algorithms, and these genes showed high diagnostic specificity for vitiligo. The PPI network showed that hub genes interacted with each other. The mRNA expression levels of five hub genes were validated in vitiligo lesions by qRT-PCR and were compatible with the bioinformatic results. Compared with controls, the abundance of activated CD4⁺ T cells, CD8⁺ T cells, immature dendritic cells and B cells, myeloid-derived suppressor cells (MDSCs), gamma delta T cells, mast cells, regulatory T cells (Tregs), and T helper 2 (Th2) cells was higher. However, the abundance of CD56 bright natural killer (NK) cells, monocytes, and NK cells was lower. Correlation analysis revealed a link between hub genes and immune infiltration. Meanwhile, we predicted the upstream TFs and miRNAs and the target compounds of hub genes.

Conclusion

Five hub mitophagy-related genes were identified and correlated with immune infiltration in vitiligo. These findings suggested that mitophagy may promote the development of vitiligo by activating immune infiltration. Our study might enhance our comprehension of the pathogenic mechanism of vitiligo and offer a treatment option for vitiligo.

Vitiligo: An immune disease and its emerging mesenchymal stem cell therapy paradigm

Melanocyte damage, innate immune response, adaptive immune response, and immune inflammatory microenvironment disorders are involved in the development of the immunological pathogenic mechanism of vitiligo. Mesenchymal stem cells are considered an ideal type of cells for the treatment of vitiligo owing to their low immunogenicity, lower rates of transplant rejection, and ability to secrete numerous growth factors, exosomes, and cytokines in vivo. The regulation of signaling pathways related to oxidative stress and immune imbalance in the immunological pathogenesis of vitiligo can improve the immune microenvironment of tissue injury sites. In addition, co-transplantation with melanocytes can reverse the progression of vitiligo. Therefore, continuous in-depth research on the immunopathogenic mechanism involved in this disease and mesenchymal stem cell-based therapy is warranted for the treatment of vitiligo in the future.