811 Mitochondrial MPZL3 in the inner root sheath regulates human hair follicle cycling ex vivo

The study investigates the role of the mitochondrial protein Myelin Protein Zero-like 3 (MPZL3) in human hair follicle (HF) cycling, particularly its impact on the anagen-catagen transition. Using ex vivo human anagen scalp HFs, researchers found that MPZL3 is predominantly expressed in the inner root sheath and that its knockdown via siRNA prolongs the anagen phase, increases hair matrix keratinocyte proliferation, and reduces the expression of TGF-b2, a catagen-inducing growth factor. Additionally, MPZL3 knockdown decreases MTCO1 expression and complex II/IV activity in the hair bulb. These findings suggest that MPZL3 is a novel regulator of the hair cycle, with potential implications for managing telogen effluvium by inhibiting MPZL3 activity.