Destruction of the stem cell Niche, Pathogenesis and Promising Treatment Targets for Primary Scarring Alopecias

Area of Science:

• Dermatology
• Pathophysiology
• Stem Cell Biology

Background:

• Primary scarring alopecias (PSAs) cause irreversible hair follicle destruction and permanent hair loss.
• The underlying pathophysiology of PSAs remains poorly understood, with follicular fibrosis and stem cell niche loss as common features.
• Understanding stem cell behavior is crucial for unraveling PSA pathogenesis.

Purpose of the Study:

• To review the pathogenesis of primary scarring alopecias.
• To investigate the fate of hair follicle stem cells in PSAs.
• To explore the contribution of stem cells to disease progression.

Main Methods:

• Literature review focusing on the pathogenesis of primary scarring alopecias.
• Analysis of stem cell behavior, including apoptosis and epigenetic reprogramming.
• Examination of the role of bulge-resident cells and their potential contribution to fibrosis.

Main Results:

• Bulge-resident stem cells are lost through inflammatory-mediated apoptosis or epigenetic reprogramming into mesenchymal-like cells.
• The proportion of stem cell loss via each mechanism is currently unknown and likely varies between individuals and PSA types.
• Follicular stem cells may differentiate into fibroblast-like cells, directly contributing to disease pathogenesis.

Conclusions:

• Stem cell loss and potential direct roles in pathogenesis are key features of primary scarring alopecias.
• Identifying specific pathogenic cells could lead to novel diagnostic and therapeutic strategies.
• Preventing epithelial-mesenchymal transition (EMT) and pro-fibrotic signaling may halt disease progression.