The Roles of Collagen XVIII and Its Endostatin Domain in Wound Healing, Hair Follicle Cycling, and Bone Development

Collagen XVIII played a significant role in various biological processes, including wound healing, hair follicle cycling, and bone development. The study found that the absence of collagen XVIII accelerated wound healing and angiogenesis, while overexpression of its endostatin domain delayed these processes and caused abnormalities in wound capillaries. In bone development, collagen XVIII was not essential, as changes in bone growth due to its absence or overexpression were mild and transient. In hair follicle cycling, overexpression of endostatin delayed hair growth and impaired angiogenesis, whereas the lack of collagen XVIII accelerated the onset of the first hair cycle. The study suggested that the longest variant of collagen XVIII might regulate Wnt-signaling in hair follicles, particularly in the bulge region containing hair follicle stem cells.