Exploring Extracellular matrix features of Pemphigus vulgaris diseased skin cells

Pemphigus vulgaris (PV) is a mucocutaneous autoimmune blistering disease caused by autoantibodies against desmosomal adhesion proteins. The most well-known autoantigens are Desmoglein 1 (DSG1) and 3 (DSG3). The targeting of these molecules results in the loss of cohesion between suprabasal keratinocytes in the epidermis in a process known as acantholysis. 

The efforts of the scientific community to unravel the roots of PV have predominantly been focused on the affected keratinocytes, leaving a possible role for fibroblasts adjacent to the blister region still in the open.

To explore this possibility, we isolated fibroblasts from diseased skin samples from PV patients and from healthy donors. We cultured the isolated fibroblasts with ascorbic acid supplementation to stimulate the deposition of extracellular matrix (ECM). After 14 days of culture we analyzed the generated cells sheets and observed that although resistant to manipulation, cell sheets obtained from diseased cells were noticeably thinner and more prone to tear than those derived from healthy fibroblasts. In order to characterize the deposited ECM we used Biocolor kits to quantify collagen, elastin and glycosaminoglycan content and observed that these are diminished in cell sheets from diseased fibroblasts. Additionally, protein expression analysis showed that cell sheets from diseased fibroblasts have decreased levels of Collagen 1, a key structural component of ECM, Fibulin-5, key in the development of elastic fibers and 67LR, an important molecule in cell adhesion to the basement membrane. Together, these results show that fibroblasts from the region surrounding the skin blisters are also affected in their structural components, highlighting a potential role for these cells in the etiology of PV that is worth of further investigation.