(021) A Novel Model to Study Fibrosis and Scarring in Vulvar Lichen Sclerosus
Authors: Fischer S , Greene C , Hopson A , Ahmed H , Little C , Bonham A , Linder M , Falsetta M 
Published: May 2023

Abstract

Introduction
Lichen sclerosus is a debilitating chronic condition where the epidermal layer of the genitals whitens, thickens, and becomes fragile. Lichen sclerosus can be extremely uncomfortable and is accompanied by a wide-range of consequences in biological, psychological, and social domains of life. Patients frequently report intense itching, burning, and pain localized to their genitals, and many experience scarring, bruising, and architectural changes. These symptoms not only limit sexual intercourse, but also impair daily functions, psychological well-being, and interpersonal relationships. Alarmingly, lichen sclerosus can occasionally develop into cancer, however, its etiology remains poorly understood. There is no cure for lichen sclerosus and current treatments only manage symptoms. As a result, we aim to establish an in vitro model of vulvar lichen sclerosus where distinct phenotypic differences between scarred and non-scarred areas can be observed. We aim to use our model to elucidate the molecular mechanisms involved in disease and to identify biomarkers that could be used to identify new targets for therapeutics.

Objective
To analyze fibroblast-to-myofibroblast transitions and production of extracellular matrix materials in cells derived from scarred vs. non-scarred tissue to improve our understanding of the scarring mechanism implicated in lichen sclerosus.

Methods
Vulvar punch biopsies collected from scarred and adjacent unaffected areas in anatomically female patients undergoing surgical treatment for lichen sclerosus were used to generate a library of primary fibroblast strains. Cells were treated with transforming growth factor beta (TGF-β) and pro-inflammatory stimuli to investigate scarring and inflammatory pathways, respectively. Fibroblast-to-myofibroblast transitions were assessed using multi-plex fluorescent live cell imaging and western blotting of myofibroblast markers, such as alpha-smooth muscle actin (α-SMA). Production of extracellular matrix proteins such as collagen, fibronectin, and calponin was also analyzed via western blotting.

Results
Morphological analysis of our collection of lichen sclerosus fibroblasts revealed that cells cultured from scarred areas tend to be large and irregularly shaped, resembling myofibroblasts. In contrast, cells from unaffected areas were observed to be thin and spindle-shaped, resembling fibroblasts. TGF-β treatment resulted in scar fibroblasts significantly upregulating expression of α-SMA, whereas this trend was not observed in controls. Our preliminary data suggests that TGF-β treatment may increase the expression of additional matrix proteins, such as collagen. This is an area of active research we are continuing to investigate.

Conclusions
Lichen sclerosus is a severely detrimental condition that is poorly characterized. Our results suggest that scarring pathways, such as TGF-β signaling cascades, may be implicated in the mechanism. Fibroblasts from scarred areas more readily undergo fibroblast-to-myofibroblast transitions, which may result in accumulation of extracellular matrix materials and fibrosis is lichen sclerosus.

Disclosure
Any of the authors act as a consultant, employee or shareholder of an industry for: SPM Therapeutics.