Human skin melanocyces: their role in normal and pathological conditions

Abstract

Melanocytes represent an important type of human skin cells. They synthesize the pigment melanin, which determines skin pigmentation and provideds protection from ultraviolet radiation and other external factors. Regulation of pigmentation involves many factors essential for development, regeneration, and aging of melanocytes and their precursors as well as the factors involved in synthesis of melanin, formation, transport and distribution of melanosomes and melanocyte-specific transcription factors that control the expression and function of all these genes. This review focused on origination and differentiation of melanocyte progenitor cells in embryogenesis and adulthood, their localization and role in skin and hair pigmentation. Particular attention was paid to the factors involved in or affecting processes of normal melanogenesis, pigmentation abnormalities due to genetic and epigenetic factors, and the processes of cell aging. The authors underlined that melanogenesis and the pigment packing and transportation to epithelial cells are complex and multifactorial processes determined by many external and internal factors, such as performance of genes, enzymes, structural proteins, and effects of hormones and medicines. Age-related changes in cells and the body as a whole are serious factors of pigmentation disorders. Despite numerous studies, information about possibilities of influencing the processes of aging or pathological disorders of skin pigmentation is extremely scarce. Identification and understanding processes involved in melanogenesis and mechanisms of changes in the functioning of human skin melanocytes will facilitate understanding the pathogenesis of pigmentation disorders and help developing new, highly effective drugs for prevention and treatment of diseases or age-related changes, specifically for prevention or reducing the risk of skin cancer.