In vitro research on vitiligo: strategies, principles, methodological options and common pitfalls

Abstract

Understanding the cellular and molecular mechanisms leading to melanocyte loss in vitiligo is a mandatory step in improving the overall management of vitiligo patients. Until now, the study of vitiligo was characterised by a fragmented approach, and it is very hard to share and compare the data obtained by the different teams. The scenario mirrors the pathogenic puzzle, but it delays a true productive focus on the disease. The in vitro research is based on different models, ranging from monolayer cell culture of epidermal and dermal cells or 3D reconstructed skin to histological data, gene expression, computer simulation profile. For each model, several different (biochemical, phenotypic, immunological) aspects have been considered, increasing the mass of data difficult to be merged. Our purpose was to provide a practical synopsis of consolidated and advanced possibilities in the study of vitiligo, showing how data have been poorly shared until now. Following a short overview of the background of the disease, the approaches, ranging from basic cell biology to molecular and 'omics' studies, are summarised. New fluorescent probes and techniques open new possibilities for functional studies. Next, intracellular and superficial markers of the melanocytes, the main involved cells, are listed. Moving the focus from the epidermal level to the systemic and subcellular ones, this review aims to propose innovative multidisciplinary options for the vitiligo understanding. This paper focuses on the major practical and theoretical questions to be solved. It may be the basis for a more coordinated and productive approach to the biological question.

A mouse model of vitiligo induced by monobenzone

“…Until now, understanding to the cellular and molecular mechanisms causing melanocyte loss in vitiligo is still unclear, partly due to the limitations of current in vitro research methodologies on vitiligo (8) and the paucity of suitable animal models. Existing mouse models of vitiligo are generally established through specifically expressing exogenic protein in skin melanocytes, leading to the destruction of the melanocytes by CD8 + CTL targeting the exogenic antigen (9)(10)(11)(12).…”

Vitiligo: A Possible Model of Degenerative Diseases

“…Since none of these processes alone are sufficient to fully explain the mechanisms of the disease, and all of the proposed mechanisms are not mutually exclusive, the convergence theories have been formulated combining biochemical, environmental and immunological events, in a permissive genetic milieu [7]. Despite considerable efforts, there are few data in the literature on in vitro studies of vitiligo epidermal melanocytes, mainly due to the fact that cells from normally pigmented skin of vitiligo patients demonstrate reduced initial seeding and proliferation capacity compared to healthy adult human skin [8]–[9].…”

“…However, despite numerous data supporting a pathogenic role of oxidative stress, there is still no consensus explanation underlying the oxidative stress-driven disappearance of melanocytes from the epidermis [18]. Even though increased susceptibility to the toxic effects of chemical oxidants or UVB has been reported in several in vitro studies [3], [9], [19] there are no convincing data demonstrating the occurrence of melanocytes death by cytotoxicity or apoptosis in vitiligo skin in vivo . Biopsy material from established lesions contains no or few melanocytes, and it is difficult to capture the essence of the melanocytes lost.…”

Interferon-γ Induces Senescence in Normal Human Melanocytes

“…Since cytokines and the related inflammatory mediators modulate the activation and skin homing of lymphocytes [6], [7], they are the important research objectives for elucidating the onset of autoimmune vitiligo. On the other hand, the discovery of redox imbalance in the vitiligo links the oxidative stress to vitiligo [8]–[10]. Recently, melanocytes in non-lesional skin of vitiligo patients were further proven to display aberrant senescence-like features [10].…”