Molecular Pathogenesis of Vitiligo: Emerging Roles of Epigenetic Regulation

Abstract

Vitiligo is a chronic acquired depigmenting disorder characterized by progressive loss of functional melanocytes and is commonly associated with other autoimmune diseases. Although genome-wide association studies have identified multiple susceptibility loci, incomplete concordance among monozygotic twins and variable onset indicate strong contributions from environmental triggers and gene–environment interactions. A convergent pathogenic sequence is emerging: oxidative stress and defective cytoprotective responses render melanocytes vulnerable, promote release of danger signals, and activate innate immune pathways, followed by adaptive cytotoxic immunity dominated by autoreactive CD8+ T cells. Keratinocyte,fibroblasts immune crosstalk driven by IFN-γ and downstream JAK–STAT signaling induces CXCL9/CXCL10, recruiting CXCR3+ T cells and sustaining an amplification loop; CXCL10–CXCR3B signaling may also directly enhance melanocyte apoptosis. Tissue-resident memory T cells further maintain local immune surveillance and contribute to relapse after therapy. Epigenetic regulation provides a mechanistic bridge that translates transient stress into durable transcriptional states in both cutaneous cells and immune compartments. We review evidence for altered DNA methylation at melanocyte differentiation and survival genes (e.g., TYR, MITF) and immune regulatory loci (e.g., NLRP1, PTPN22), as well as contributions from histone modifications and non-coding RNAs that shape cytokine production and checkpoint pathways. Finally, we discuss translational opportunities, including topical JAK inhibition, epigenetic biomarkers for prognosis and treatment response, and emerging strategies for targeted epigenetic modulation. Integrated epigenomic approaches have the potential to advance the development of next-generation therapies.

INTRODUCTION

Vitiligo is a chronic acquired cutaneous disorder characterized by the progressive loss of functional melanocytes, resulting in the appearance of sharply demarcated depigmented macules (Bolognia and Pawelek, 1988). Clinically, the disease is broadly categorized into segmental and non-segmental forms based on its distribution and progression. Genetic factors clearly contribute to the development of vitiligo. The general population incidence is reported to be 0.5% to 2.0% (Alkhateeb et al., 2003; Krüger and Schallreuter, 2012). Although approximately 91% of vitiligo cases are sporadic (Roberts et al., 2019), the prevalence is markedly increased among close relatives of affected individuals, reaching about 7% in first-degree relatives (Alkhateeb et al., 2003). Although numerous theories have been advanced to explain the etiology of vitiligo, the underlying pathogenic mechanisms may differ among patients. Among the proposed pathogenic theories, the autoimmune hypothesis is the most supported by existing evidence (Harris, 2016; Ongenae et al., 2003; Westerhof and d’Ischia, 2007). Epidemiological evidence indicates that patients with vitiligo have an increased prevalence of several other autoimmune disorders, including autoimmune thyroid diseases, rheumatoid arthritis, adult-onset type 1 diabetes, pernicious anemia, Addison’s disease, systemic lupus erythematosus, and alopecia areata (Alkhateeb et al., 2003; Iacovelli et al., 2005; Lee et al., 2023). Notably, these autoimmune conditions are also observed at higher frequencies among first-degree relatives of vitiligo probands, supporting the notion that these disease associations are driven, at least in part, by shared genetic susceptibility (Jin et al., 2012).

Overall, nearly 8% of patients report at least one affected family member, consistent with a polygenic pattern of inheritance (Laberge et al., 2005). Major landmark genome-wide association studies (GWAS) have identified over 50 susceptibility loci (Jin et al., 2012, 2016), primarily involving the major histocompatibility complex (MHC) (Cavalli et al., 2016; Hayashi et al., 2016) and genes associated with innate/adaptive immunity (NLRP1, IFIH1, CTLA4, FOXP3) and melanin biosynthesis (TYR, MC1R) (Jin et al., 2007, 2010; Okamura and Suzuki, 2025). However, genetic-only models are insufficient to fully explain the disease’s susceptibility and heterogeneity. The fraction of disease risk attributable to genetic variation is termed heritability (h2), with the remainder attributable to the environment. Vitiligo heritability is quite high; about 80% of vitiligo risk is genetically based, with the remaining 20% attributable to environmental factors (Spritz and Santorico, 2021). Most common genetic variants linked to vitiligo susceptibility largely related to immune regulation, apoptotic pathways, and melanocyte biology (Spritz and Santorico, 2021). Recent study reported that vitiligo genetic risk and age of onset are strongly inversely correlated and subjects with higher common-variant polygenic risk tend to develop vitiligo at an earlier age (Roberts et al., 2024). However, studying vitiligo cases from North America and Europe, these investigators observed a shift over the period 1970-2004 from the mean onset of 14.6 ± 9.4 years of age in 1970 to 30.2 ± 17.3 years of age in 2004 (Jin et al., 2020). In addition, a cross-sectional study reported that the highest adjusted incidence rates in the United States from 2015 to 2019 were observed among Asian American patients and individuals aged 60 to 69 years (Mastacouris et al., 2023). However, genetic-only models are insufficient to fully explain the disease’s susceptibility and heterogeneity. These changes in age suggest that genetic factors do not fully explain the actual onset of the disease and point toward the increasing influence of unknown environmental triggers (Cojocaru et al., 2008; Roberts et al., 2024). Furthermore, the concordance rate among monozygotic twins is only 23%, despite sharing identical genetic sequences (Alkhateeb et al., 2003). Epigenetic regulation has emerged as a crucial molecular interface between environmental exposures and altered gene regulation. Epigenetic modifications, particularly DNA methylation, can connect genetic risk with environmental triggers, contributing to the development and progression of vitiligo (Okamura and Suzuki, 2025). In this review, we discuss the molecular pathogenesis of vitiligo, focusing on epigenetic regulation with an emphasis on DNA methylation and explore the therapeutic implications of these findings.

PATHOGENESIS OF VITILIGO: FROM CELLULAR STRESS TO IMMUNE ATTACK

The complex architecture of vitiligo susceptibility is rooted in a delicate balance between genetic predisposition and the breakdown of immune tolerance. While the disease is primarily characterized by the loss of melanocytes, its close clinical and genetic association with various other autoimmune conditions suggests a broader systemic dysregulation (Spritz, 2012). Epidemiological data have consistently shown that vitiligo does not occur in isolation but often co-segregates with a specific spectrum of autoimmune disorders within affected individuals and their families (Alkhateeb et al., 2003). This clustering of diseases points toward shared susceptibility loci that govern fundamental immune checkpoints, where specific genetic variations provide a permissive environment for the development of multifaceted autoimmune responses (Gill et al., 2016). Epidemiological evidence indicates that patients with vitiligo have an increased prevalence of several other autoimmune disorders, including autoimmune thyroid diseases, rheumatoid arthritis, adult-onset type 1 diabetes, pernicious anemia, Addison’s disease, systemic lupus erythematosus, and alopecia areata (Alkhateeb et al., 2003; Iacovelli et al., 2005; Lee et al., 2023). Notably, these autoimmune conditions are also observed at higher frequencies among first-degree relatives of vitiligo probands, supporting the notion that these disease associations are driven, at least in part, by shared genetic susceptibility (Alkhateeb et al., 2003).

Genetic susceptibility and interplay between autoimmunity

Previous genome-wide association studies (GWAS) have further elucidated this link, identifying shared susceptibility loci involved in immune regulation, such as PTPN22, CTLA4, and NLRP1, which act as common genetic foundations for multiple autoimmune phenotypes (Okamura and Suzuki, 2025; Spritz, 2012). Among these, HLA class I and II alleles are particularly critical as they govern the presentation of self-antigens and the subsequent activation of autoreactive T cells (Cavalli et al., 2016; Hayashi et al., 2016). While these shared genetic variants establish a permissive environment for autoimmunity, the relatively low concordance rate among monozygotic twins underscores that genetic predisposition alone is insufficient for disease onset, pointing toward the essential role of environmental and epigenetic factors (Alkhateeb et al., 2003; Krüger and Schallreuter, 2012; Spritz and Santorico, 2021). Building upon this, recent evidence highlights that the critical “interplay” between genetic susceptibility and environmental triggers is largely mediated by epigenetic mechanisms. Environmental stressors, such as oxidative stress, act upon this genetically vulnerable background to initiate an “epigenetic switch.” Specific epigenetic modifications at these susceptibility loci accelerate the transition from latent genetic risk to active clinical depigmentation, placing the epigenome at the critical interface of vitiligo pathogenesis (Jin et al., 2016; Roberts et al., 2024; Wu et al., 2025)

Oxidative stress: The trigger of intrinsic cellular vulnerability

The process of melanin synthesis poses intrinsic oxidative risk to melanocytes. The enzymatic reactions required to convert tyrosine into melanin, catalyzed by tyrosine hydroxylase and phenylalanine hydroxylase, result in the release of hydrogen peroxide (H₂O₂), a major contributor to reactive oxygen species (ROS) (Meyskens et al., 2001). In vitro exposure of cultured human melanocytes to exogenous stressors (e.g., heat shock, hydrogen peroxide) induced cell death in melanocytes derived from vitiligo patients, in contrast to melanocytes from healthy controls. Under physiological conditions, the antioxidant transcription factor nuclear erythroid 2–related factor 2 (NRF2) enhances cellular defense mechanisms by inducing autophagy and the expression of antioxidant enzymes. In vitiligo, however, this protective response to oxidative stress is impaired (Jimbow et al., 2001; Maresca et al., 1997). These findings indicate that melanocytes from vitiligo patients possess an intrinsic vulnerability to oxidative stress. Vitiligo melanocytes have impaired Nrf2-Kelch like ECH associated protein 1 (Keap1) antioxidant response element (ARE) signaling and decreased activation of the antioxidant enzyme system (Gawkrodger, 2009). Yue Le et al. suggested that impaired NRF2 signaling in oxidatively stressed melanocytes leads to the elevated expression of C-X-C motif chemokine receptor 3B (CXCR3B) and increased apoptosis, rendering vitiligo melanocytes more susceptible to oxidative stress induced apoptosis (Le et al., 2024).

Oxidative stress effects beyond direct cytotoxicity (Seneschal et al., 2025). ROS activate the unfolded protein response (UPR), leading to the release of damage-associated molecular patterns (DAMPs) that amplify inflammatory signaling. Inflammatory signaling via interferon-gamma (IFN-γ) further disrupts melanocyte adhesion via (Matrix Metalloproteinase-9) MMP-9 activation, resulting in E-cadherin cleavage and concurrently impairing regenerative WNT/β-catenin signaling (Delmas and Larue, 2019; Dong et al., 2023). These processes collectively hinder repigmentation and promote cellular senescence. Senescent melanocytes express p53 and acquire a senescence-associated secretory phenotype, characterized by the release of proinflammatory cytokines and chemokines that recruit and activate immune cells, including CD8+ T lymphocytes (Seneschal et al., 2025).

Cellular innate immunity and innate activation

Vitiligo pathogenesis involves environmental stressors, intrinsic cellular vulnerability, and dysregulated immune responses, with the central event being the loss of melanocytes mediated by autoreactive CD8⁺ cytotoxic T cells (Frisoli et al., 2020; Seong and Oh, 2024). Accumulating evidence indicates that oxidative stress and effector memory CD8⁺ T cells (CD8⁺ TEMs) play pivotal roles in melanocyte destruction (Boniface et al., 2018; Chen et al., 2019; Richmond et al., 2013). Innate signaling pathways activated by cellular stress lead to adaptive autoimmune responses against melanocytes (Richmond et al., 2013; Xie et al., 2016). The onset of vitiligo is typically triggered by external oxidative stress, such as ultraviolet (UV) radiation, chemical exposure, or physical trauma, which initiates the release of danger signals and subsequent T-cell activation (Cojocaru et al., 2008; Okamura and Suzuki, 2025; Roberts et al., 2024). In response to these stressors, melanocytes express danger signals and release melanocyte-specific antigens, DAMPs, and HSP70 (Richmond et al., 2013), and these molecules stimulate the innate immune system and trigger a downstream inflammatory cascade that ultimately leads to activation of the adaptive immune response (Frisoli et al., 2020). Activated innate immune cells and stressed keratinocytes contribute to the amplification of inflammation (Seneschal et al., 2025). IFN-α derived from plasmacytoid dendritic cells and IFN-γ produced by innate lymphoid cells stimulate keratinocytes to secrete C-X-C motif chemokine ligand 9 (CXCL9) and CXCL10 (Jacquemin et al., 2017; Tulic et al., 2019). Autoreactive CD8⁺ T cells migrate into the skin under the guidance of the CXCL9/CXCL10–CXCR3 axis and contribute to melanocyte loss through direct cytotoxicity as well as the secretion of type 1 cytokines, including IFN-γ and TNF (Boniface et al., 2018; Jacquemin et al., 2020; Richmond et al., 2018). Therefore, innate immunity bridges the gap between cellular stress and adaptive autoimmunity (Seneschal et al., 2025).

Keratinocyte–fibroblast- melanocyte–immune crosstalk: The IFN-γ–CXCL9/10 amplification loop

The destruction of melanocytes in vitiligo is not a simple isolated event but the result of a complex, multidirectional crosstalk between keratinocytes, fibroblasts, melanocytes, and the infiltrating immune cells. For example, early in the pathogenesis, keratinocyte dysfunction such as the downregulation of Aquaporin-3 can directly exacerbate oxidative stress in neighboring melanocytes, rendering them more vulnerable to subsequent immune attacks (Kim et al., 2023). This interaction is primarily driven by the IFN-γ–CXCL9/10–CXCR3 signaling axis (Fig. 1), which serves as the central engine for disease progression and maintenance (Frisoli et al., 2020; Seong and Oh, 2024). Once activated, autoreactive CD8⁺ T cells secrete IFN-γ and TNF, exerting both direct effects on melanocytes and indirect effects mediated through keratinocytes and fibroblasts (Boukhedouni et al., 2020). When IFN-γ, a key cytokine produced by autoreactive CD8⁺ T cells, binds to its specific receptors on the surface of keratinocytes, fibroblasts or other skin cells, it triggers JAK–STAT pathway. This intracellular signaling cascade leads to the robust transcriptional up-regulation and secretion of the Th1-type chemokines, CXCL9 and CXCL10. Interestingly, while IFN-γ expression from infiltrating T cells in vitiligo lesions remains at relatively low levels, the signal is dramatically amplified through the surrounding keratinocytes and fibroblasts (Richmond et al., 2017; Xu et al., 2022). Recent studies reported that these fibroblasts act as “key inflammatory amplifiers,” by producing CXCL9 and CXCL10 in response to IFN-γ, and effectively reinforce T-cell recruitment (Seneschal et al., 2025; Xu et al., 2022) This feedforward mechanism promotes further migration of CD8⁺ T cells into the dermis and amplifies IFN-γ production, ultimately resulting in melanocyte destruction and depigmentation (Wu et al., 2024). The recruited CD8⁺ T cells express the CXCR3 receptor, allowing them to follow the chemokine gradient toward the melanocytes. Beyond mere recruitment, the crosstalk involves direct pro-apoptotic signaling to the melanocytes themselves. Melanocytes in vitiligo patients exhibit a strong basal expression of the CXCR3 isoform B (CXCR3B), a variant directly regulated by IFN-γ (Tulic et al., 2019). When CXCL10 binds to CXCR3B on the melanocyte surface, it directly induces cellular apoptosis, providing a non-cell-mediated mechanism of pigment cell loss. The recruited CD8⁺ T cells not only follow the chemokine gradient toward melanocytes but also execute targeted cytotoxicity through multiple effector mechanisms. Upon antigen recognition via MHC class I–melanosomal peptide complexes (e.g., tyrosinase, gp100, MART-1), these T cells release perforin and granzyme B to induce melanocyte apoptosis, while FasL–Fas signaling provides an additional non-perforin-dependent pathway (Richmond et al., 2013; Upadhya et al., 2025). Furthermore, the remaining melanocytes are not passive victims; they are actively drawn into the immune cascade. Activated by the IFN-γ–rich milieu, residual melanocytes in perilesional skin have been reported to aberrantly express MHC class II and adhesion molecules such as ICAM-1, a phenotype compatible with non-professional antigen-presenting cells that can, at least theoretically, participate in the local restimulation of autoreactive T cells and sustain anti-melanocytic immunity (al Badri et al., 1993; Frisoli et al., 2020; Richmond et al., 2013; van den Wijngaard et al., 2001). This intricate interaction between these three cells establishes a self-amplifying positive feedback loop, ensuring that even a localized stress event can lead to widespread and persistent depigmentation (Meyskens et al., 2001).

Fig. 1.

Schematic illustration of pathogenesis of vitiligo. In vitiligo, melanocytes respond to external stress by releasing danger signals such as DAMPs and HSP70 and activate to the innate immune system. Subsequently, adaptive CD8⁺ T cells become activated and secrete IFN-γ. IFN-γ activates JAK–STAT pathway and promotes the secretion of CXCL9 and CXCL10 by keratinocytes and fibroblasts, enhancing the recruitment of autoreactive CD8⁺ T cells. Furthermore, melanocytes of vitiligo patients have increased basal expression of CXCR3 isoform B and activation of CXCR3B induce cell apoptosis. (DAMPs: damage-associated molecular patterns, HSP70: heat shock protein 70 , IFN-γ: interferon-γ , JAK–STAT: the Janus kinase–signal transducer and activator of transcription , CXCR3: C-X-C motif chemokine receptor 3 , CXCL9: C-X-C motif chemokine ligand 9 ,CXCL10: C-X-C motif chemokine ligand 9).

Melanocyte apoptosis

In vitiligo melanocytes exposed to ROS such as hydrogen peroxide, intrinsic apoptotic pathways are readily activated, including loss of mitochondrial membrane potential and release of cytochrome c into the cytosol (Chen et al., 2021; Lin et al., 2024; Liu et al., 2006). Oxidative stress activates stress-responsive signaling pathways, including JNK, p38 MAPK, and NF-κB, thereby promoting the caspase cascade, while chronic activation of ER stress–UPR signaling further contributes to melanocyte apoptosis (Mansuri et al., 2014; Mucha et al., 2025). Repeated oxidative damage and accumulation of hydrogen peroxide induce a robust DNA damage response (DDR, ATM/ATR–p53 axis), leading to cell-cycle arrest or apoptosis, and such overactivation of DDR has been proposed to contribute to the selective loss of vitiligo melanocytes (Chang and Ko, 2023; Sarkar and Gaddameedhi, 2020; Yan et al., 2014). Recently, Yue Le et al. demonstrated that, under oxidative stress, impaired NRF2-mediated antioxidant signaling in vitiligo melanocytes increases splicing toward the B isoform of the CXCR3 receptor (CXCR3B), resulting in markedly enhanced CXCR3B-dependent apoptosis in response to CXCL10 and providing a direct molecular link between oxidative stress and the IFN-γ/CXCL10 inflammatory chemokine axis (Le et al., 2024). CXCR3B has already been identified by previous studies as being highly expressed at baseline in vitiligo melanocytes and as a key receptor capable of inducing melanocyte apoptosis upon CXCL10 stimulation alone, and the findings by Le and colleagues indicate that CXCR3B-mediated cell death is further amplified when coupled with defective NRF2 function (Chen et al., 2021). Thus, these interconnected apoptotic programs from mitochondrial cytochrome c release and MAPK/caspase cascades to p53-mediated DDR and NRF2/CXCR3B-dependent cell death collectively render vitiligo melanocytes hypersensitive to oxidative stress, forging a critical molecular bridge between intrinsic cellular vulnerability and the IFN-γ–CXCL10 immune axis.

IMMUNE-MEDIATED MOLECULAR MECHANISMS

CD8⁺ T cell cytotoxicity: Antigen recognition and effector mechanisms

The central event in vitiligo pathogenesis is melanocyte destruction mediated by autoreactive CD8⁺ cytotoxic T cells, which recognize melanosomal antigens such as tyrosinase (TYR), gp100, and MART-1 presented via MHC class I (Spritz, 2012; Wang et al., 2025a). These T cells deploy multiple effector mechanisms, including perforin/granzyme B-mediated apoptosis, FasL–Fas signaling, and IFN-γ-dependent non-cytolytic pathways (Chen et al., 2021; Harris et al., 2012). Circulating melanocyte-specific CD8+ T cells are increased in patients with vitiligo, particularly during active disease, and express skin-homing markers, indicating that the immune system is primed to target melanocytes (Lang et al., 2001; Seneschal et al., 2025; van den Boorn et al., 2009).

Tissue-resident memory T cells and immune surveillance

Vitiligo lesions are enriched with effector memory T cells (CD8⁺ TEM) and skin-resident memory T cells (CD8⁺ T_RM) expressing CD69, CD103 (αEβ7 integrin), and CX3CR1, enabling long-term tissue residency and rapid reactivation upon antigen re-encounter (Boniface et al., 2018; Le et al., 2024). Melanocyte-specific CD8⁺T_RM cells persist in lesional and peri-lesional skin and express CXCR3, NKG2D, and the IL-15 receptor chain CD122 (Boniface et al., 2018; Jacquemin et al., 2020; Richmond et al., 2018) These T_RM cells maintain persistent immune surveillance, contributing to disease chronicity and relapse (Riding and Harris, 2019). T_RM cells, probably maintained by IL-15 and TGF-β, produce high levels of IFN-γ and TNF and, together with recirculating T cells, drive a pro-inflammatory state via JAK signaling to sustain disease (Boniface et al., 2018; Jacquemin et al., 2020; Richmond et al., 2018; Seneschal et al., 2025). Consequently, targeting the IL-15 signaling pathway has emerged as a highly promising therapeutic strategy to permanently deplete these persistent memory cells and prevent localized repigmentation failure (Richmond et al., 2018).

The IFN-γ–CXCL9/10–CXCR3 amplification axis

The central event in vitiligo pathogenesis is the destruction of melanocytes mediated by autoreactive CD8⁺ cytotoxic T cells (Chen et al., 2021; Riding and Harris, 2019). CD8⁺ TEM and CD8⁺ T_RM target melanocytes by recognizing specific antigens, leading to progressive and persistent depigmentation (Boniface et al., 2018; Chen et al., 2019). A critical driver of this process is the IFN-γ–CXCL9/10–CXCR3 signaling axis, which acts as the molecular engine for disease progression (Liu et al., 2024a). As comprehensively detailed in Section 2.4, crosstalk with keratinocytes, melanocytes, and fibroblasts amplifies inflammation, sustaining a vicious cycle linking cellular stress, innate and adaptive immunity. The key molecular drivers involved in this intricate immune crosstalk between T cells, keratinocytes, fibroblasts, and melanocytes are summarized in Table 1.

Table 1.

Key molecular drivers in vitiligo immune crosstalk

Category	Molecule	Source cell	Target/Function	Ref.
Cytokine	IFN-γ	CD8⁺ T cells	Activates JAK/STAT in keratinocytes	(Frisoli et al., 2020; Seong and Oh, 2024)
Chemokine	CXCL9/ CXCL10	Keratinocytes, Fibroblasts	Recruitment of CXCR3⁺ T cells	(Richmond et al., 2017; Tulic et al., 2019; Xu et al., 2022)
Receptor	CXCR3/ CXCR3B	T cells/Melanocytes	T cell homing/ Melanocyte apoptosis	(Le et al., 2024; Richmond et al., 2013)
Survival Factor	IL-15	Keratinocytes	Maintenance of CD8⁺ TRM (Relapse)	(Boniface et al., 2018; Chen et al., 2019)
DAMPs	HSP70	Stressed Melanocytes	Innate immune activation (DCs)	(Maresca et al., 1997)
Inhibitor	SOCS/ PIAS	All cells	Negative regulation of JAK/STAT (Defective in vitiligo)	(Hu et al., 2021; Villarino et al., 2015)

Dysregulated immune checkpoints

Regulatory T cells (Tregs) cells are decreased in number, accompanied by functional defects in patients with vitiligo (Giri et al., 2022; Shah et al., 2024). Polymorphisms in CTLA4 and PTPN22 further exacerbate immune dysregulation, linking genetic susceptibility to unchecked cytotoxicity (Giri et al., 2020; Okamura and Suzuki, 2025; Wang et al., 2025b). The profound clinical implications of these dysregulated immune checkpoints are most evident in the phenomenon of immune checkpoint inhibitor (ICI)-induced vitiligo. Patients receiving anti-PD-1 or anti-CTLA-4 therapies for melanoma frequently develop vitiligo-like depigmentation as an immune-related adverse event, directly demonstrating that pharmacological blockade of these checkpoints unleashes latent, melanocyte-specific autoimmunity (Hua et al., 2016; Teulings et al., 2015).

EPIGENETIC REGULATION IN VITILIGO

Epigenetic mechanisms, encompassing DNA methylation, histone modifications, and non-coding RNAs (miRNAs, lncRNAs), provide a dynamic interface between environmental triggers and heritable gene expression changes in vitiligo pathogenesis (Lai et al., 2025; Okamura and Suzuki, 2025). Unlike immutable genetic variants, these marks respond rapidly to stressors such as UV radiation, chemical oxidants, and ROS, thereby translating extrinsic insults into stable disease phenotypes (Inoue, 2025; Lin et al., 2021).

DNA methylation dysregulation

Genome-wide DNA methylation profiling has revealed hypermethylation of melanocyte survival genes (e.g., TYR, MITF) and hypomethylation of immune activation loci (NLRP1, PTPN22) in vitiligo peripheral blood mononuclear cells (PBMCs) and lesional skin (He and Wang, 2025; Shi et al., 2016; Wu et al., 2025). Specifically, promoter hypermethylation of TYR in lesional melanocytes correlates with reduced transcription and increased ROS sensitivity, establishing a feed-forward loop of melanocyte vulnerability (Wang et al., 2025b). Zhao et al. found that the average genomic DNA methylation level in PBMCs of patients with vitiligo was significantly higher which was associated with elevated mRNA expression of DNA methyltransferases 1 (DNMT1) and multiple methylated DNA-binding domain proteins (MBDs) (Zhao et al., 2010). A study of DNA methylation reported that differences between vitiligo melanocytes from the human vitiligo melanocyte cell line PIG3V and the human normal melanocyte cell line PIG1 (Pu et al., 2021). They integrated these results with analysis the correlation between differentially methylated levels and differentially expressed genes. They reported total of 12 genes that affect melanocyte melanogenesis, cellular oxidative stress, and other important biological processes, suggesting the significant contribution of the status of DNA methylation modification to vitiligo (Pu et al., 2021). Further integrative analysis of transcriptome data identified 264 differentially methylated and expressed genes and their enrichment in genes, such as cell division, pigmentation, metabolism, and peroxidase activity (Liu et al., 2024b). Another study of DNA methylation reported that 63.29% were hypermethylated and 36.71% were hypomethylated in vitiligo lesion and 79 significantly differentially methylated CpG sites in vitiligo lesions compared with non-lesional skins (Chen et al., 2024).

Histone modifications, chromatin remodeling, and non-coding RNAs

While DNA methylation is a well-characterized epigenetic driver in vitiligo, the dynamic orchestration of chromatin remodeling through histone modifications and non-coding RNAs (ncRNAs) provides another crucial layer of gene regulation (Table 2). Integrated methylome-transcriptome analysis of vitiligo melanocyte lines revealed histone deacetylases2 (HDAC2) hypomethylation and upregulation, suggesting histone acetylation dysregulation contributes to melanocyte dysfunction. (Abdallah et al., 2017). Specifically, the overactivation of HDACs induces repressive chromatin states at the Microphthalmia-associated Transcription Factor (MITF) promoter, profoundly impairing melanogenesis and survival under oxidative stress. Furthermore, an imbalance in histone methylation—such as the enrichment of activating marks (e.g., H3K4me3) and the loss of repressive marks (e.g., H3K27me3) at IFN-γ-responsive gene loci—facilitates the robust transcription of chemokines like CXCL9 and CXCL10 in local skin cells, thereby amplifying the autoimmune response (Wu et al., 2025). Beyond structural chromatin changes, a growing body of evidence highlights the pivotal role of non-coding RNAs in vitiligo pathogenesis. For instance, specific microRNAs such as miR-25 are significantly upregulated in vitiligo, where they directly target and downregulate MITF, thereby exacerbating melanocyte loss (Shi et al., 2016). In the immune compartment, the upregulation of miR-155 strongly amplifies IFN-γ signaling and promotes a Th1/Tc1-skewed environment (Yu et al., 2022). Long non-coding RNAs (lncRNAs) also play multifaceted roles; concurrently, lncRNA MALAT1 promotes EZH2 recruitment to MITF promoter, silencing melanogenesis (Vanan et al., 2025). Conversely, the downregulation of protective lncRNAs, such as TUG1, further sensitizes melanocytes to oxidative stress-induced apoptosis (Nie et al., 2024). Together, these findings position the complex network of histone modifications and ncRNAs as a therapeutically targetable bridge between vitiligo’s genetic predisposition and environmental initiation, highlighting profound implications for precision medicine approaches.

Table 2.

Key epigenetic markers and their pathogenic roles in vitiligo

Epigenetic Mechanism	Target Gene/Marker	Target Cell Type	Pathogenic Effect & Molecular Outcome	Ref
DNA Methylation	CXCL10 (Hypomethylation)	Keratinocytes, Fibroblasts/Immune Cells	Upregulation of CXCL10 enhances the recruitment of autoreactive CXCR3+ CD8+ T cells into the epidermis.	(Wu et al., 2025; Zhao et al., 2010)
	POMC (Hypermethylation)	Melanocytes	Decreased expression of pro-opiomelanocortin (POMC), impairing local melanin synthesis and cytoprotective signaling.
Histone Modification	Histone Deacetylation (via HDAC overactivation)	Melanocytes	Deacetylation at the MITF promoter represses its transcription, leading to melanocyte dysfunction and impaired melanogenesis under oxidative stress.	(Abdallah et al., 2017; Wu et al., 2025)
	H3K4me3 (Enrichment)/H3K27me3 (Loss)	Keratinocytes, Fibroblasts	Active chromatin states at IFN-γ-responsive gene loci (e.g., CXCL9, CXCL10) exacerbate the pro-inflammatory microenvironment.
Non-Coding RNAs	miR-25 (Upregulation)	Melanocytes	Directly targets and downregulates MITF, impairing melanosome maturation and reducing melanocyte survival.	(Šahmatova et al., 2016; Shi et al., 2016)
	miR-155 (Upregulation)	T Cells/ Melanocytes	Amplifies IFN-γ signaling and Th1/Tc1-skewed immune responses; promotes melanocyte antigen presentation.
	lncRNA MEG3 (Downregulation)	Melanocytes	Loss of MEG3 exacerbates oxidative stress-induced apoptosis and downregulates tyrosinase activity.

CANDIDATE EPIGENETIC REGULATORS: FROM MELANOCYTES TO IMMUNITY

Several genes have been identified as targets of epigenetic dysregulation in vitiligo, linking environmental stressors to melanocyte loss and immune dysregulation (Okamura and Suzuki, 2025; Upadhya et al., 2025). ANXA2R (Annexin A2 Receptor) exhibits promoter hypermethylation in vitiligo lesions, correlating with its downregulation in both melanocytes and keratinocytes; this hypermethylation enhances oxidative stress-induced melanocyte apoptosis via caspase-3/9 activation and impairs keratinocyte stem cell factor (SCF) secretion, disrupting melanocyte survival (Chen et al., 2024). Furthermore, the BET proteins (BRD2/4)–MITF axis governs melanocyte differentiation and pigment synthesis but is epigenetically disrupted in vitiligo; BET inhibitors suppress MITF target genes (TYR, TYRP1), while vitiligo lesions show altered BRD4 recruitment to MITF-bound enhancers, impairing melanogenesis (Trivedi et al., 2020). In melanocytes, NRF2 promoter hypermethylation compromises ROS detoxification (Sorour et al., 2021). These epigenetic alterations create a vicious cycle of melanocyte vulnerability and immune hyperactivity, positioning DNMT inhibitors and HDAC modulators as promising therapeutic targets (Okamura and Suzuki, 2025).

While the epigenetic alterations of targets like ANXA2R and NRF2 have been directly confirmed in vitiligo lesions, it is crucial to delineate these from emerging, theoretical targets that require future investigation. In genetically susceptible individuals, the environmental factors disrupt immune homeostasis, leading to a breakdown of autoimmune tolerance and the potential development of autoimmune disease. The epigenome plays a crucial role in maintaining immune system integrity, and disturbances in its regulatory mechanisms can contribute to the pathogenesis of autoimmunity (Gibson et al., 2022). Therefore, if immune-related genes are epigenetically regulated through DNA methylation in response to environmental stressors, such mechanisms are likely to contribute to disease development. The c-Jun N-terminal kinase (JNK) signaling is activated in response to cellular stress signals such as UV radiation and ROS (Kumar et al., 2015). The JNK pathway is one of the mitogen-activated protein kinase (MAPK) pathways and is controlled through a cascade of kinase activations. It plays a critical role in various physiological processes, including cell differentiation, apoptosis, neural function, and embryonic development (Kumar et al., 2015).

The DUSP22 gene (also known as JKAP, JNK pathway–associated phosphatase) acts as a critical negative regulator of the JNK pathway and T-cell receptor (TCR) signaling by directly inactivating Lck, a Src family tyrosine kinase. While the deficiency or inactivation of DUSP22 has been well-documented to induce T cell hyperactivation via sustained JNK signaling in other autoimmune disease models, its specific mechanistic sequence in human vitiligo currently represents a highly plausible, yet extrapolated, model. The hypothesis that DUSP22 promoter hypermethylation leads to sustained JNK activation thereby fueling autoreactive T cells in vitiligo is strongly supported by findings in these parallel conditions.

The dysregulation of DUSP22 is a known contributor to excessive inflammation in various autoimmune diseases, suggesting that its epigenetic downregulation may similarly fuel autoreactive T cells in vitiligo. However, whether this specific epigenetic-signaling axis is directly linked to the pathogenesis within the skin lesions of vitiligo patients requires further in vivo experimental validation.

Another set of strongly proposed candidate genes involves the PIAS (Protein Inhibitor of Activated STAT) family (PIAS1-4). PIAS proteins interact with STAT dimers to inhibit their binding to DNA, thereby blocking the classical JAK/STAT signal transduction that is heavily relied upon by cytokines like IFN-γ (Hu et al., 2021; Villarino et al., 2015). Given that the dysregulation of the JAK/STAT signaling pathway is a major engine for progressive depigmentation, the potential epigenetic silencing of PIAS could remove a crucial immune checkpoint. Further in vivo studies to determine whether the epigenetic silencing of these theoretical immune-regulator genes, such as DUSP22 or PIAS, directly links environmental triggers to the development of human vitiligo will be of immense interest for future investigation (Fig. 2).

Fig. 2.

Epigenetic vicious cycle in vitiligo pathogenesis.

INTEGRATIVE MODEL OF EPIGENETIC DYSREGULATION IN VITILIGO

The pathogenesis of vitiligo can be synthesized into an integrative model where epigenetic modifications act as the bridge between environmental stress and cellular dysfunction. External triggers, such as UV radiation and chemical exposure, induce oxidative stress which elevates ROS levels and disrupts antioxidant defenses like NRF2 pathways subsequently altering the DNA methylation landscape in both melanocytes and immune cells (Chang and Ko, 2023). A possible mechanism of this model is the epigenetic silencing of protective regulator, such as DUSP22, where promoter hypermethylation leads to transcriptional repression and sustained JNK/p38 MAPK activation. This removes a critical brake on TCR signaling, rendering melanocytes highly vulnerable to apoptosis while simultaneously amplifying IFN-γ-mediated autoimmune responses via CD8⁺ T cell effector functions (Castro-Sanchez et al., 2020; Wang et al., 2025b; Zhao et al., 2010). Consequently, vitiligo emerges as a condition of epigenetically deregulated stress and immune signaling characterized by a vicious cycle of melanocyte loss, and self-sustaining inflammation leading to progressive depigmentation. Therapeutic targeting of DNMT/HDAC pathways holds promise to break this cycle (He and Wang, 2025; Huang et al., 2025). Thus, repositioning DNMT inhibitors and HDAC modulators emerges as a compelling therapeutic strategy to disrupt this epigenetic vicious cycle, restoring melanocyte resilience while attenuating CD8⁺ T cell-driven autoimmunity in vitiligo.

THERAPEUTIC IMPLICATIONS OF EPIGENETIC REGULATION

Limitation of current vitiligo treatments

Current treatments primarily rely on immunomodulatory approaches such as topical calcineurin inhibitors, topical corticosteroids, phototherapy, and systemic corticosteroids; however, achieving satisfactory therapeutic outcomes remains challenging. Therapeutic approaches for vitiligo remain suboptimal due to the lack of curative interventions, the long duration of treatment, and the relapse after discontinuation of treatment. T_RM cells are characterized by their long-lived residence within the skin. Based on their ability to reside in tissues for long periods and rapidly induce immune responses, they were strong candidates for inducing relapse of vitiligo lesions (Frisoli et al., 2020). Developed vitiligo lesion persists by Trms in the skin, facilitated by IL-15-dependent signaling (Richmond et al., 2018; Seong and Oh, 2024; Villarino et al., 2015). Recently, topical ruxolitinib, a pan-JAK inhibitor, has been approved for vitiligo in the FDA (Sheikh et al., 2022), and ruxolitinib cream have achieved 50–75% facial repigmentation in phase III clinical trials (Rosmarin et al., 2022). Regarding the effect of JAK inhibitors on Trm cells, it was found that JAK inhibitors help prevent vitiligo progression by blocking the influx of T cells into the skin, but do not affect T cells that have already been established (Azzolino et al., 2021). This finding suggests that stopping treatment may lead to disease relapse and that sustained therapeutic effects may not be achieved (Azzolino et al., 2021; Seong and Oh, 2024). In recent years, significant progress has been made in understanding vitiligo pathogenesis, leading to notable advances in treatment; however, challenges remain. The integration of epigenetic and immune-targeted therapies may represent a promising therapeutic approach.

Epigenetic biomarkers

The identification of disease-specific DNA methylation signatures offers significant potential for clinical application. Differentially methylated regions (DMRs) in genes like ANXA2R (lesional skin/melanocytes) dehypermethylated via Illumina EPIC 850K arrays correlate with disease activity, melanocyte apoptosis, and SCF secretion impairment. These biomarkers enable epigenetic stratification for predicting progression and treatment response, facilitating personalized vitiligo management (Chen et al., 2024; Huang et al., 2025; Yang et al., 2021; Zhao et al., 2010). ANXA2R (Annexin A2 Receptor) exhibits promoter hypermethylation in vitiligo lesions, resulting in its downregulation in keratinocytes and melanocytes; this hypermethylation under oxidative stress triggers caspase-3 activation and melanocyte apoptosis while inhibiting keratinocyte stem cell factor (SCF) secretion, thereby impairing melanocyte survival (Chen et al., 2024).

Targeting epigenetic pathways

Targeting the “epigenome” represents a novel frontier in vitiligo therapy. DNMT modulators (e.g., 5-aza-2’-deoxycytidine) reverse hypermethylation (Chen et al., 2024; Wu et al., 2025), while BET inhibitors (e.g., VYN201/JQ1) disrupt the BET-MITF axis to restore melanogenesis and reduce MMP-9/inflammation (Bridgewater, 2024; Trivedi et al., 2020). Furthermore, targeted epigenetic genome editing technologies could lead to promising therapeutic advances. CRISPR/dCas9-based tools have emerged as a key approach in epigenetic therapy. Unlike non-selective HDAC/DNMT inhibitors or ncRNA-based strategies, the dCas9 system enables precise and reversible regulation of specific gene loci without inducing DNA double-strand breaks by coupling catalytically inactive Cas9 to epigenetic effectors such as DNA methyltransferases, Ten-eleven translocation methylcytosine dioxygenases, or histone acetyltransferases (e.g., p300) (Dai et al., 2020; He and Wang, 2025). Ideally, combined with JAK inhibitors like ruxolitinib which blocks IFN-γ-STAT1 signaling, with epigenetic agents can achieve a synergistic effect achieve synergy: epigenetic drugs “reset” T cell hyper-reactivity and boost melanocyte survival (Ferreira et al., 2025; He and Wang, 2025; Trivedi et al., 2020).

Toward mechanism-based precision therapy

The transition toward mechanism-based precision therapy addresses vitiligo’s root epigenetic causes. Reversing silencing of protective genes (DUSP22, ANXA2R, NRF2) may halts the self-amplifying loop of destruction, with conventional treatments can be reach better treatment outcome. Integrated epigenetic-omics studies will drive next-generation treatments (Chen et al., 2024; Dong et al., 2025).

In conclusion, epigenetic dysregulation orchestrates vitiligo’s vicious cycle of melanocyte destruction and immune hyperactivity, positioning epigenetic targeted therapies as transformative precision medicine strategies to restore pigment homeostasis and halt disease progression.

CONCLUSIONS AND FUTURE PERSPECTIVES

Vitiligo is increasingly recognized as a multifactorial autoimmune depigmenting disorder in which genetic predisposition intersects with environmental stress to initiate melanocyte injury and culminate in immune-mediated melanocyte loss. Pathologically, lesional skin is characterized by depletion of functional melanocytes with immune infiltrate dominated by cytotoxic T cells and a keratinocyte-driven inflammatory microenvironment that supports chronicity and relapse, including persistence of resident memory T cells in previously affected skin. Beyond sequence-level susceptibility, epigenetic regulation provides a coherent framework for disease heterogeneity and variable onset, positioning the epigenome as a mediator that converts transient exposures particularly oxidative stress into sustained changes in cutaneous and immune cell programs.

Among epigenetic mechanisms, DNA methylation has emerged as a clinically actionable layer, with methylome studies in peripheral blood and lesional skin identifying widespread differentially methylated CpG sites enriched in pathways related to pigmentation, oxidative stress responses, apoptosis, antigen presentation, cytokine signaling, and immune tolerance. Ultimately, combining immune-targeted therapies with rational epigenetic modulation and, longer term, locus-specific epigenome editing to reset pathogenic regulatory states may enable more durable repigmentation by restoring melanocyte resilience while re-establishing immune homeostasis. To overcome the limitations of current mono-therapies, integrating targeted epigenetic modulators with established immunotherapies offers a promising synergistic approach. The potential clinical benefits and mechanistic synergies of these combination strategies are summarized in Table 3.

Table 3.

Proposed synergy of combination therapies targeting immune and epigenetic pathways in vitiligo

Therapy Combination	Primary Targets	Synergistic Mechanism of Action	Expected Clinical Benefits
JAK Inhibitor+HDAC Inhibitor	JAK1/2 (e.g., Ruxolitinib)+Histone Deacetylases (e.g., Valproic acid)	JAKi halts the IFN-γ signaling loop, while HDACi reverses the repressive chromatin state at the MITF promoter, directly rescuing melanogenesis.	Rapid arrest of depigmentation combined with accelerated, durable repigmentation.
JAK Inhibitor+DNMT Inhibitor	JAK1/2+DNA Methyltransferases (e.g., 5-Aza)	JAKi suppresses effector T cells, while DNMTi reverses the hypermethylation of negative regulators (e.g., DUSP22, PIAS), restoring long-term immune tolerance.	Prevention of relapse after JAKi withdrawal by restoring natural immune homeostasis.
Antioxidants+Epigenetic Modulators	ROS Scavengers+SIRT1 Activators (e.g., Resveratrol)	Antioxidants neutralize immediate ROS damage, while SIRT1 activation (a class III HDAC) deacetylates and stabilizes protective transcription factors like FOXO3, promoting melanocyte survival.	Effective stabilization of active, rapidly progressing vitiligo lesions.