Aberrant ETS-1 signalling impedes the expression of cell adhesion molecules and matrix metalloproteinases in non-segmental vitiligo.

Cell adhesion is a complex process that involves multiple molecules on the cell surface (ie cell adhesion molecules [CAMs]), surrounding cells and extracellular matrix (ECM). Repigmentation in vitiligo is dependent on the ECM remodelling and cellular migration, primarily attributed to the transcriptional activation of matrix metalloproteinases (MMPs). In this study, we aimed to demonstrate the role of ETS-1 signalling in the regulation of MMPs and CAMs. Therefore, we studied the expression of ETS-1, MMPs (MMP-2, MMP-9) and CAMs including E-cadherin, ITGA-1 and ICAM-1 in vitiligo (both active and stable) ex vivo. Further, we compared melanocyte morphology and their adhesion towards collagen IV and laminin between control and vitiligo groups in vitro. Also, we silenced ETS-1 in melanocytes cultured from control skin and observed post-silencing effect on above-mentioned MMPs and CAMs. We perceived absent ETS-1 and significantly reduced CAMs and MMPs in vitiligo compared with normal skin. Scanning electron microscopy (SEM) revealed a translucent material surrounding individual melanocytes in stable vitiligo and controls, whereas active vitiligo melanocytes demonstrated loss of this extracellular substance. Adhesion assays revealed significantly decreased binding of cultured melanocytes to collagen IV and laminin V plates in both stable and active vitiligo. Importantly, ETS-1 silencing resulted in significantly reduced expression of CAMs and MMPs. In conclusion, absent ETS-1 expression in both stable and active non-segmental vitiligo seems to impede the expression of CAMs, apart from MMPs, probably leading to progressive depigmentation in active disease and absence of spontaneous repigmentation in stable disease.