Parkin-mediated ubiquitination of DCUN1D1: Implications for CXCL10 regulation in vitiligo

Summary: Abstract Body: Vitiligo is a skin disorder characterized by the loss of skin pigmentation resulting from the destruction of melanocytes. Our prior research identified DCUN1D1 as a novel regulator of CXCL10, which is linked to mitochondrial dysfunction. Analysis of RNA sequencing data indicated a reduction in the expression of Parkin, a molecule associated with mitophagy, in patients with vitiligo. Parkin operates as an E3 ubiquitin ligase. In light of these observations, we propose that Parkin ubiquitinates DCUN1D1, thereby modulating CXCL10 levels during the progression of vitiligo. This study evaluated the expression levels of Parkin and DCUN1D1 in both vitiligo patients and mouse models. To investigate their interactions, HaCaT cells were transfected with Flag-DCUN1D1, Myc-PRKN, or HA-Ub, followed by co-immunoprecipitation and Western blot analysis. Mitochondrial activity and mitophagy were assessed following various treatments, including CCCP administration. Additionally, HaCaT cells were transfected with DCUN1D1 or varying concentrations of Parkin to measure CXCL10 levels. The supernatant from HaCaT cells was subsequently incubated with melanocytes for 48 hours, after which apoptosis was evaluated. The findings revealed that DCUN1D1 was upregulated while Parkin was downregulated in both vitiligo patients and mice. Furthermore, Parkin was shown to interact with and ubiquitinate DCUN1D1 at lysine 27 (K27). Elevated levels of Parkin were found to mitigate the decreases in mitochondrial activity and mitophagy induced by DCUN1D1, significantly downregulating CXCL10 levels and reducing melanocyte apoptosis. In conclusion, this study provides compelling evidence that Parkin-mediated ubiquitination of DCUN1D1 plays a critical role in regulating CXCL10 levels in vitiligo, thereby contributing to a deeper understanding of the pathogenesis of this condition. Shiyu Jin¹, Tingru Dong¹, Cuiping Guan² 1. Hangzhou Third Hospital Affiliated to Zhejiang Chinese Medical University, Hangzhou, China. 2. Hangzhou Third People's Hospital, Hangzhou, China. Pigmentation, Melanoma, and Melanoma Immune Surveillance