Global activation of CD8+ cytotoxic T lymphocytes correlates with an impairment in regulatory T cells in patients with generalized vitiligo.
Lili Yang,Yi Wei,Ji Yang,Yue Sun,Weimin Shi,Ming Li
PloS one
Melanocyte-specific CD8(+) cytotoxic T lymphocytes (CTLs) play a pivotal role in vitiligo-induced depigmentation. Yet, the mechanisms underlying the high frequency of generalized autoimmune disorders associated with generalized vitiligo (GV) are unknown. We hypothesized that an imbalance between activated CD8(+) CTLs and regulatory T cells (Tregs) exists in patients with GV . Assessment of the circulating CD8(+) CTLs and Tregs by flow cytometric analysis revealed an obvious expansion of CD8(+) CTLs and a concomitant decrease in Treg cells in GV patients. The percentages of skin infiltrating CD8(+) CTLs and Tregs were evaluated by immunohistochemistry and revealed dramatically increased numbers of both CD8(+) CTLs and Tregs in the perilesional skin of GV patients. However, peripheral Tregs were impaired in their ability to suppress the proliferation and cytolytic capacity of autologous CD8(+) T cells, suggesting that a functional failure of Tregs and the hyper-activation of CD8(+) CTLs may contribute to progressive GV. Our data indicate that reduced numbers and impaired function of natural Tregs fail to control the widespread activation of CD8(+) CTLs, which leads to the destruction of melanocytes and contributes to the elevated frequency of various associated autoimmune diseases. This knowledge furthers our understanding of the mechanisms of immune tolerance that are impaired in GV patients and may aid in the future development of effective immunotherapy for GV patients.
10.1371/journal.pone.0037513
Ruxolitinib cream for treatment of vitiligo: a randomised, controlled, phase 2 trial.
Rosmarin David,Pandya Amit G,Lebwohl Mark,Grimes Pearl,Hamzavi Iltefat,Gottlieb Alice B,Butler Kathleen,Kuo Fiona,Sun Kang,Ji Tao,Howell Michael D,Harris John E
Lancet (London, England)
BACKGROUND:Vitiligo is a chronic autoimmune disease resulting in skin depigmentation and reduced quality of life. There is no approved treatment for vitiligo repigmentation and current off-label therapies have limited efficacy, emphasising the need for improved treatment options. We investigated the therapeutic potential of ruxolitinib cream in patients with vitiligo and report the efficacy and safety results up to 52 weeks of double-blind treatment. METHODS:We did a multicentre, randomised, double-blind, phase 2 study for adult patients with vitiligo in 26 US hospitals and medical centres in 18 states. Patients with depigmentation of 0·5% or more of their facial body surface area (BSA) and 3% or more of their non-facial BSA were randomly assigned (1:1:1:1:1) by use of an interactive response technology system to receive ruxolitinib cream (1·5% twice daily, 1·5% once daily, 0·5% once daily, or 0·15% once daily) or vehicle (control group) twice daily on lesions constituting 20% or less of their total BSA for 24 weeks. Patients in the control group in addition to patients in the 0·15% once daily group who did not show a 25% or higher improvement from baseline in facial Vitiligo Area Scoring Index (F-VASI) at week 24 were re-randomised to one of three higher ruxolitinib cream doses (0·5% once daily, 1·5% once daily, 1·5% twice daily). Patients in the 0·5% once daily, 1·5% once daily, or 1·5% twice daily groups remained at their original dose up to week 52. Patients, investigators, and the study sponsor (except members of the interim analysis and primary endpoint analysis data monitoring teams) remained masked to treatment assignment throughout the study. The primary endpoint was the proportion of patients achieving a 50% or higher improvement from baseline in F-VASI (F-VASI50) at week 24, assessed in the intention-to-treat population. The study is registered with ClinicalTrials.gov, NCT03099304. FINDINGS:Between June 7, 2017, and March 21, 2018, 205 patients were screened for eligibility, 48 were excluded and 157 patients (mean age, 48·3 years [SD 12·9]; 73 [46%] male and 84 [54%] female) were randomly assigned to either an intervention group or the control group. 32 (20%) of 157 were assigned to the control group, 31 (20%) to the 0·15% once daily group, 31 (20%) to the 0·5% once daily group, 30 (19%) to the 1·5% once daily group, and 33 (21%) to the 1·5% twice daily group. F-VASI50 at week 24 was reached by significantly more patients given ruxolitinib cream at 1·5% twice daily (15 [45%] of 33) and 1·5% once daily (15 [50%] of 30) than were treated with vehicle (one [3%] of 32). Four patients had serious treatment-emergent adverse events (one patient in the 1·5% twice daily group developed subdural haematoma; one patient in the 1·5% once daily group had a seizure; one patient in the 0·5% once daily group had coronary artery occlusion; and one patient in the 0·5% once daily group had oesophageal achalasia), all of which were unrelated to study treatment. Application site pruritus was the most common treatment-related adverse event among patients given ruxolitinib cream (one [3%] of 33 in the 1·5% twice daily group; three [10%] of 30 in the 1·5% once daily group; three [10%] of 31 in the 0·5% once daily group; and six [19%] of 31 in the 0·15% once daily group)with three [9%] of 32 patients showing application site pruritis in the control group. Acne was noted as a treatment-related adverse event in 13 (10%) of 125 patients who received ruxolitinib cream and one (3%) of 32 patients who received vehicle cream. All treatment-related adverse events were mild or moderate in severity and similar across treatment groups. INTERPRETATION:Treatment with ruxolitinib cream was associated with substantial repigmentation of vitiligo lesions up to 52 weeks of treatment, and all doses were well tolerated. These data suggest that ruxolitinib cream might be an effective treatment option for patients with vitiligo. FUNDING:Incyte.
10.1016/S0140-6736(20)30609-7
RIPK1 regulates the survival of human melanocytes upon endoplasmic reticulum stress.
Sun Xuecheng,Wang Tao,Huang Bo,Ruan Gaobo,Xu Aie
Experimental and therapeutic medicine
Vitiligo is a common congenital or acquired disfiguring skin disorder. At present, endoplasmic reticulum (ER) stress has been identified to serve a critical role in the pathogenesis of vitiligo. Receptor-interacting serine/threonine-protein kinase 1 (RIPK1) is a protein serine/threonine kinase. The specific molecular mechanism of RIPK1 in human melanocytes upon ER stress remains to be determined. In the present study, RIPK1 was significantly downregulated in tunicamycin (TM)-induced ER stressed-human melanocytes. Subsequently, to explore the role of RIPK1 in ER stress-induced human melanocytes, human melanocytes were transfected with control or RIPK1 plasmids for 24 h and then treated with 3 µM TM for 48 h. Reverse transcription-quantitative PCR and western blot analysis indicated that the expression levels of protein kinase R-like endoplasmic reticulum kinase, eukaryotic translation initiation factor 2 subunit 1 and CCAAT-enhancer-binding protein homologous protein were significantly increased in the TM-treated group compared with the controls. In addition, the effect of high RIPK1 expression on ER stress-induced human melanocyte survival was studied. The present results indicated that TM inhibited cell viability and promoted apoptosis in human primary epidermal melanocytes. Western blot analysis demonstrated that the expression of Bax and caspase-3 was upregulated and the expression of Bcl-2 was downregulated in TM-treated human melanocytes. The effects of TM on human melanocytes were reversed by RIPK1 overexpression. Therefore, RIPK1 overexpression may have an effect on the PI3K/AKT/mTOR signaling pathway in human melanocytes under ER stress. The results of the current study demonstrated that RIPK1 could protect human melanocytes from cell damage induced by ER stress by regulating the PI3K/AKT/mTOR and ER stress signaling pathways, thereby serving a protective role in the occurrence and development of vitiligo.
10.3892/etm.2020.8575
Regulatory T cells from active non-segmental vitiligo exhibit lower suppressive ability on CD8+CLA+ T cells.
Lin Mao,Zhang Bao-Xiang,Shen Nan,Dong Xue-Jiao,Zhang Ci,Qi Xiao-Yi,Zhu Jie,Li Yu-Zhong,Man Mao-Qiang,Tu Cai-Xia
European journal of dermatology : EJD
BACKGROUND:Recent studies have shown that vitiligo is a T-cell mediated autoimmune disease. Skin-homing cytotoxic T lymphocytes expressing cutaneous lymphocyte-associated antigen (CLA) have been suggested to be responsible for the destruction of melanocytes in vitiligo. An aberration in the suppressive function of regulatory T cells (Tregs) has been reported in vitiligo patients. However, whether the weakened suppressive ability of the Tregs contributes to hyper-activated skin homing CD8(+)CLA(+) T cells remains to be determined. OBJECTIVES:To investigate the inhibition of circulating Tregs on the proliferation of autologous CD8(+)CLA(+) T cells in non-segmental vitiligo patients. METHODS:CD8(+)CLA(+) T cells and Tregs were obtained from the peripheral blood of 13 non-segmental vitiligo patients and 7 controls. The proliferative responses of CD8(+)CLA(+) T cells were assessed in the absence or presence of autologous Tregs, and the levels of Transforming Growth Factor β1(TGF-β1) and IL-10 in culture supernatants were detected by enzyme-linked immunosorbent assay. RESULTS:The proliferative responses of circulating CD8(+)CLA(+) T cells in the presence of Tregs were significantly higher in the active vitiligo than in the stable vitiligo and control groups. Tregs from active vitiligo patients exhibited a lower inhibitory effect on proliferation of CD8(+)CLA(+) T cells. The levels of TGF-β1 produced by Tregs were significantly lower in active vitiligo than other groups and anti-TGF-β1 antibodies could abrogate the suppressive function of Tregs. CONCLUSIONS:The functional activity of Tregs is compromised in active vitiligo patients. TGF-β1 plays an important role in the autoimmune mechanism of the disease.
10.1684/ejd.2014.2436
Oxidative stress-induced IL-15 trans-presentation in keratinocytes contributes to CD8 T cells activation via JAK-STAT pathway in vitiligo.
Chen Xuguang,Guo Weinan,Chang Yuqian,Chen Jiaxi,Kang Pan,Yi Xiuli,Cui Tingting,Guo Sen,Xiao Qian,Jian Zhe,Li Kai,Gao Tianwen,Li Shuli,Liu Ling,Li Chunying
Free radical biology & medicine
Oxidative stress and effector memory CD8 T cells have been greatly implicated in vitiligo pathogenesis. However, the crosstalk between these two crucial pathogenic factors has been merely investigated. IL-15 has been regarded as an important cytokine exerting its facilitative effect on memory CD8 T cells function in various autoimmune diseases. In the present study, we initially discovered that the IL-15 expression was significantly increased in vitiligo epidermis and highly associated with epidermal HO content. In addition, epidermal IL-15 expression was mainly derived from keratinocytes. Then, we showed that oxidative stress promoted IL-15 and IL-15Rα expression as well as IL-15 trans-presentation by activating NF-κB signaling in keratinocytes. What's more, the trans-presented IL-15, rather than the secreted one, was accounted for the potentiation of CD8 T activation. We further investigated the mechanism underlying trans-presented IL-15 in potentiating CD8 T activation and found that the blockage of IL-15-JAK-STAT signaling could be a potent therapeutic approach. Taken together, our results demonstrate that oxidative stress-induced IL-15 trans-presentation in keratinocytes contributes to the activation of CD8 T, providing a novel mechanism by which oxidative stress initiates autoimmunity in vitiligo.
10.1016/j.freeradbiomed.2019.05.011
Apigenin protects human melanocytes against oxidative damage by activation of the Nrf2 pathway.
Cell stress & chaperones
Vitiligo is a chronic, autoimmune destruction of melanocytes, resulting in progressively expanding depigmented skin patches. Severity of the disorder, which affects approximately 1% of humans, may be mitigated using topical corticosteroids combined with phototherapy; along with other clinical strategies; however, no definitive cures are currently available. Here, the capacity of apigenin, a plant-derived aglycone, to inhibit oxidative stress-mediated melanocyte depletion in vitro using a PIG3V vitiligo perilesional melanocyte cell model is evaluated. PIG3V cells, treated with selected doses of apigenin, were challenged with HO, then assessed for viability and the oxidative stress-related parameters: superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), and malondialdehyde (MDA) by enzyme-linked immunoabsorbent assay (ELISA). Additionally, expression of nuclear factor erythroid 2p45 (NF-E2)-related factor 2 (Nrf2) and downstream targets was detected using Western blotting. Outcomes demonstrated that compared with negative control cultures, apigenin-treated cells exhibited enhanced viability. Likewise, apigenin enhanced expression of the cellular anti-oxidants SOD, CAT, and GSH-Px, but inhibited production of MDA, an oxidative stress biomarker. Interestingly, the expression and nuclear localization of the Nrf2 transcription factor, an important regulator oxidative stress and its downstream target genes, was significantly increased by apigenin treatment. Apigenin influence on Nrf2 was further validated by experiments demonstrating that Nrf2 knockdown cells failed to exhibit significant apigenin-mediated effects on cell viability and oxidative stress. Apigenin's non-toxicity and ability to affect multiple oxidative stress-related parameters through its effects on Nrf2 signaling in melanocytes suggests that it may prove to be a valuable therapeutic tool in long-term management of vitiligo.
10.1007/s12192-020-01071-7