CHAPTER 10: MicroRNAs in Skin Development, Function and Disorders

Mammalian skin is the outermost layer of the body, which protects internal organs from the environment. During embryogenesis, the epidermis, hair follicle and sebaceous glands arise from a single layer of epidermal progenitor cells, a process regulated by an array of mechanistic pathways. In adults, homeostasis of skin integrity and function is maintained by skin stem cells, having properties of self-renewability and differentiation. MicroRNAs (miRNAs) are central to the development and functioning of the skin, made evident by the emergence of health disorders following their dysregulation. A number of transcriptomics studies have shown that numerous miRNAs are associated with physiological processes such as skin cell development, differentiation and aging, and regulate pathological processes (e.g., scleroderma, psoriasis and melanoma). In wound healing, miRNAs in multiple cellular compartments act in a temporally resolved manner to achieve tissue repair. Importantly, miRNAs are transferred from one cellular compartment to another, making the significance of miRNAs in wound healing even more interesting. This chapter provides an overview of miRNA-dependent mechanisms implicated in skin development, function and disorders.