Hair follicles, which are connected to sebaceous glands in the skin, undergo cyclic periods of regeneration, degeneration, and rest throughout adult life in mammals. The crucial function of hair follicle stem cells is to maintain these hair growth cycles. Another vital aspect is the activity of melanocyte stem cells, which differentiate into melanin-producing melanocytes, contributing to skin and hair pigmentation. Sebaceous gland stem cells also have a pivotal role in maintaining the skin barrier by regenerating mature sebocytes. These stem cells are maintained in a specialized microenvironment or niche and are regulated by internal and external signals, determining their dynamic behaviors in homeostasis and hair follicle regeneration. The activity of these stem cells is tightly controlled by various factors secreted by the niche components around the hair follicles, as well as immune-mediated damage signals, aging, metabolic status, and stress. In this study, we review these diverse stem cell regulatory and related molecular mechanisms of hair regeneration and disease conditions. Molecular insights would provide new perspectives on the disease mechanisms as well as hair and skin disorder treatment.

毛囊与皮肤中的皮脂腺相连，在哺乳动物的整个成年生活中经历再生、退化和休息的循环周期。毛囊干细胞的关键功能是维持这些毛发生长周期。另一个重要方面是黑素细胞干细胞的活性，它分化为产生黑色素的黑素细胞，有助于皮肤和头发色素沉着。皮脂腺干细胞通过再生成熟的皮脂腺细胞，在维持皮肤屏障方面也发挥着关键作用。这些干细胞维持在专门的微环境或生态位中，并受到内部和外部信号的调节，决定它们在体内平衡和毛囊再生中的动态行为。这些干细胞的活性受到毛囊周围微环境成分分泌的各种因素以及免疫介导的损伤信号、衰老、代谢状态和压力的严格控制。在这项研究中，我们回顾了这些不同的干细胞调节以及毛发再生和疾病状况的相关分子机制。分子见解将为疾病机制以及头发和皮肤疾病的治疗提供新的视角。