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Vitiligo is a cutaneous depigmenting autoimmune disease caused by the extensive destruction of epidermal melanocytes. Convincing data has defined a critical role for oxidative stress in the pathogenesis of vitiligo. Oxeiptosis is a caspase-independent cell death modality that was reportedly triggered by oxidative stress and operative in pathogen clearance. However, whether oxeiptosis exists in oxidative stress-induced melanocytes demise in vitiligo remains undetermined. In the present study, we initially found that other cell death modalities might exist in addition to the well-recognized apoptosis and necroptosis in H 2 O 2 -treated melanocytes. Furthermore, AIFM1 was found to be dephosphorylated at Ser116 in oxidative stress-induced melanocytes death, which was specific to oxeiptosis. Moreover, KEAP1 and PGAM5, upstream of the AIFM1 in oxeiptosis, were found to operate in melanocytic death. Subsequently, the KEAP1-PGAM5-AIFM1 signaling pathway was proved to be involved in oxidative stress-triggered melanocytes demise through the depletion of KEAP1 and PGAM5. Altogether, our study indicated that oxeiptosis might occur in melanocytes death under oxidative stress and contribute to the pathogenesis of vitiligo.

Background The activation of CD8 + T cells and their trafficking to the skin through JAK-STAT signaling play a central role in the development of vitiligo. Thus, targeting this key disease pathway with innovative drugs is an effective strategy for treating vitiligo. Natural products isolated from medicinal herbs are a useful source of novel therapeutics. Demethylzeylasteral (T-96), extracted from Tripterygium wilfordii Hook F, possesses immunosuppressive and anti-inflammatory properties. Methods The efficacy of T-96 was tested in our mouse model of vitiligo, and the numbers of CD8 + T cells infiltration and melanocytes remaining in the epidermis were quantified using whole-mount tail staining. Immune regulation of T-96 in CD8 + T cells was evaluated using flow cytometry. Pull-down assay, mass spectrum analysis, molecular docking, knockdown and overexpression approaches were utilized to identify the target proteins of T-96 in CD8 + T cells and keratinocytes. Results Here, we found that T-96 reduced CD8 + T cell infiltration in the epidermis using whole-mount tail staining and alleviated the extent of depigmentation to a comparable degree of tofacitinib (Tofa) in our vitiligo mouse model. In vitro, T-96 decreased the proliferation, CD69 membrane expression, and IFN-γ, granzyme B, (GzmB), and perforin (PRF) levels in CD8 + T cells isolated from patients with vitiligo. Pull-down assays combined with mass spectrum analysis and molecular docking showed that T-96 interacted with JAK3 in CD8 + T cell lysates. Furthermore, T-96 reduced JAK3 and STAT5 phosphorylation following IL-2 treatment. T-96 could not further reduce IFN-γ, GzmB and PRF expression following JAK3 knockdown or inhibit increased immune effectors expression upon JAK3 overexpression. Additionally, T-96 interacted with JAK2 in IFN-γ-stimulated keratinocytes, inhibiting the activation of JAK2, decreasing the total and phosphorylated protein levels of STAT1, and reducing the production and secretion of CXCL9 and CXCL10. T-96 did not significantly inhibit STAT1 and CXCL9/10 expression following JAK2 knockdown, nor did it suppress upregulated STAT1-CXCL9/10 signaling upon JAK2 overexpression. Finally, T-96 reduced the membrane expression of CXCR3, and the culture supernatants pretreated with T-96 under IFN-γ stressed keratinocytes markedly blocked the migration of CXCR3 + CD8 + T cells, similarly to Tofa in vitro. Conclusion Our findings demonstrated that T-96 might have positive therapeutic responses to vitiligo by pharmacologically inhibiting the effector functions and skin trafficking of CD8 + T cells through JAK-STAT signaling.

Background Although dendritic cell (DC)- and CD8 + T cell-mediated autoimmunity is critical for destroying melanocytes in vitiligo, treatment options remain limited by the absence of therapies that cotarget both cell types. Methods We first evaluated the association between the immunoregulatory metabolite itaconate and disease development, by determining human vitiligo serum itaconate levels and monitoring depigmentation progression in Acod1 knockout (KO) mice with endogenous itaconate deficiency. We further evaluated the therapeutic efficacy of the itaconate derivative, dimethyl itaconate (DI) in mice and assessed its effects on cutaneous infiltration and the functional properties of DCs and CD8 + T cells in vivo and ex vivo. The gene signatures and signaling pathways involved in DI-treated CD8 + T cells were also assessed. Results We observed an elevation of circulating itaconate in vitiligo patients, whereas itaconate deficiency accelerated depigmentation in Acod1 KO mice after vitiligo induction. The administration of DI halted vitiligo development and promoted repigmentation, with elevated circulating itaconate levels, increased melanocyte counts, and decreased cutaneous CD8 + T cell densities. Mechanistically, DI dampened CD8 + T cell activation (CD69), effector function (Interferon-γ, IFN-γ), cytotoxicity (Gzmb), proliferation, and proinflammatory gene expression (Csf1, Ifitm1, CD49a, NKG2D, and NKG2A), partly by suppressing the Janus kinase (JAK)‒STAT pathway. Moreover, DI-treated mice exhibited reduced cutaneous DC infiltration, as well as fewer DCs with mature and migratory phenotypes. Conclusions Our findings identify DI as a metabolite-derived small molecule that protects against autoimmune injury by cotargeting DC and CD8 + T cell responses, thereby demonstrating a promising therapeutic strategy and providing a foundation for treating vitiligo and other cell-specific autoimmune diseases. Graphical Abstract

Vitiligo is a disfiguring disease featuring chemokines-mediated cutaneous infiltration of autoreactive CD8 + T cells that kill melanocytes. Copious studies have indicated that virus invasion participates in the pathogenesis of vitiligo. IFIH1 , encoding MDA5 which is an intracellular virus sensor, has been identified as a vitiligo susceptibility gene. However, the specific role of MDA5 in melanocyte death under virus invasion is not clear. In this study, we first showed that the expression of anti-CMV IgM and MDA5 was higher in vitiligo patients than healthy controls. Then, by using Poly(I:C) to imitate virus invasion, we clarified that virus invasion significantly activated MDA5 and further potentiated the keratinocyte-derived CXCL10 and CXCL16 which are the two vital chemokines for the cutaneous infiltration of CD8 + T cells in vitiligo. More importantly, IFN-β mediated by the MDA5-MAVS-NF-κB/IRF3 signaling pathway orchestrated the secretion of CXCL10 via the JAK1-STAT1 pathway and MDA5-meidiated IRF3 transcriptionally induced the production of CXCL16 in keratinocytes under virus invasion. In summary, our results demonstrate that MDA5 signaling orchestrates the aberrant skin immunity engaging in melanocyte death via mediating CXCL10 and CXCL16 secretion, which supports MDA5 as a potential therapeutic target for vitiligo under virus invasion.

Vitiligo is a depigmented skin disorder caused by a variety of factors, including autoimmune, metabolic disturbance or their combined effect, etc. Non-targeted metabolomic analyses have denoted that dysregulated fatty acids metabolic pathways are involved in the pathogenesis of vitiligo. However, the exact category of fatty acids that participate in vitiligo development and how they functionally affect CD8 + T cells remain undefined. We aimed to determine the difference in specific fatty acids among vitiligo patients and healthy individuals and to investigate their association with clinical features in patients with vitiligo. Serum levels of fatty acids in 48 vitiligo patients and 28 healthy individuals were quantified by performing ultra-performance liquid chromatography-tandem mass spectrometry. Univariate and multivariate analyses were carried out to evaluate the significance of differences. Moreover, flow cytometry was used to explore the effect of indicated fatty acids on the function of CD8 + T cells derived from patients with vitiligo. We demonstrated that serological level of alpha-linolenic acid (ALA) was markedly upregulated, while that of arachidonic acid (ARA), arachidic acid (AA) and behenic acid were significantly downregulated in patients with vitiligo. Moreover, ALA levels were positively associated with vitiligo area scoring index (VASI) and ARA was a probable biomarker for vitiligo. We also revealed that supplementation with ARA or nordihydroguaiaretic acid (NDGA) could suppress the function of CD8 + T cells. Our results showed that vitiligo serum has disorder-specific phenotype profiles of fatty acids described by dysregulated metabolism of polyunsaturated fatty acids. Supplementation with ARA or NDGA might promote vitiligo treatment. These findings provide novel insights into vitiligo pathogenesis that might add to therapeutic options.

Vitiligo is a cutaneous depigmentation disease due to loss of epidermal melanocytes. Accumulating evidence has indicated that oxidative stress plays a vital role in vitiligo via directly destructing melanocytes and triggering inflammatory response that ultimately undermines melanocytes. Folic acid (FA), an oxidized form of folate with high bioavailability, exhibits potent antioxidant properties and shows therapeutic potential in multiple oxidative stress-related diseases. However, whether FA safeguards melanocytes from oxidative damages remains unknown. In this study, we first found that FA relieved melanocytes from H2O2-induced abnormal growth and apoptosis. Furthermore, FA enhanced the activity of antioxidative enzymes and remarkably reduced intracellular ROS levels in melanocytes. Subsequently, FA effectively activated nuclear factor E2-related factor 2 (Nrf2) pathway, and Nrf2 knockdown blocked the protective effects of FA on H2O2-treated melanocytes. Additionally, FA inhibited the production of proinflammatory HMGB1 in melanocytes under oxidative stress. Taken together, our findings support the protective effects of FA on human melanocytes against oxidative injury via the activation of Nrf2 and the inhibition of HMGB1, thus indicating FA as a potential therapeutic agent for the treatment of vitiligo.

To reveal the prognostic significance of serum albumin (ALB) concentration in endometrial cancer (EC) patients in China. 345 EC patients were enrolled in a single center, and the preoperative serum ALB concentration were measured. Kaplan–Meier curve analysis and Cox proportional hazards regression model were performed to evaluate the associations between ALB concentration and overall survival (OS) of EC patients. The EC patients with lower preoperative serum ALB concentration exhibited a significantly poorer OS (p < 0.05). Univariate analysis and multivariate analysis indicated that serum ALB concentration was an independent prognostic factor of unfavorable OS for EC patients. Our results showing that ALB concentration may serve as an independent prognostic factor for EC patients.