Col17a1-KO Mouse

Col17a1, also known as the gene encoding type XVII collagen (COL17A1/BP180), is a critical molecule for hair follicle stem cell (HFSC) maintenance. It is a hemidesmosome component at the epidermal-dermal junction and plays important roles in maintaining the stability between the dermis and epidermis. COL17A1 is involved in multiple biological processes, such as skin homeostasis, epidermal regeneration, and stem cell-related activities [1,2].

In mouse models, DNA damage response in HFSCs causes proteolysis of Col17a1, triggering HFSC aging. Aged HFSCs are cyclically eliminated from the skin, leading to hair follicle miniaturization. The aging process can be recapitulated by Col17a1 deficiency and prevented by forced maintenance of COL17A1 in HFSCs, indicating its key role in the stem-cell-centric aging program of the epithelial mini-organ [1]. Also, stem cells with higher COL17A1 expression outcompete those with lower expression through cell competition in the skin, and loss of COL17A1 limits this competition, causing skin aging [2].

In conclusion, Col17a1 is essential for maintaining skin-related stem cell functions and skin homeostasis. Mouse models with Col17a1 deficiency or forced expression have revealed its significance in hair follicle aging and skin aging processes, providing potential targets for anti-aging therapeutic intervention.