Hair Follicles as Micro-Organs: MicroRNA-Mediated Control of Growth, Cycling, and Fiber Traits

This review examines the critical role of microRNAs (miRNAs) in regulating hair follicle biology, particularly in sheep and goats, where they influence wool and cashmere production. Hair follicles are complex mini-organs affected by genetic, environmental, and epigenetic factors, with miRNAs emerging as key regulators of cell fate, proliferation, differentiation, and apoptosis. They modulate gene expression and signaling pathways essential for follicle formation, cyclic regeneration, and fiber traits. The review proposes a systems-level framework where miRNA networks interact with canonical signaling pathways to orchestrate follicle development and regeneration. While miRNAs are integral to follicle biology, further in vivo validation is needed to fully understand their mechanistic roles and therapeutic potential.