Expression of the heat shock protein-27 in the adult human scalp skin and hair follicle: Hair cycle–dependent changes

BackgroundHeat shock protein (HSP) is a molecular chaperone involved in protein folding, assembly, and transport and in the regulation of cell growth and differentiation. HSP27 protein is expressed in murine hair follicle (HF) and in human skin during fetal development. In this investigation we hypothesized that HSP27 protein is expressed in the human scalp skin and its expression in HF changes with the transitions form anagen → catagen → telogen stages.MethodsTo test this hypothesis, the immunoreactivity of HSP27 protein was examined in human scalp skin by immunofluorescent method. A total of 50 normal human scalp skin biopsy specimens were examined (healthy women, age 53-57 years). In each case, 50 HF were analyzed (35, 10, and 5 follicles in anagen, catagen, and telogen, respectively).ResultsHSP27 protein expression was prominent in human scalp anagen, and weak in both catagen and telogen HFs. Within HF, HSP27 protein immunoreactivity was prominent in the outer root sheath, inner root sheath, precorteocytes, and corteocytes of the hair shaft. In addition, HSP27 protein expression was prominent in the epidermis, sebaceous glands, sweat glands, and arrector pili muscles.LimitationsOnly some types of heat shock proteins are known to date. Also, our knowledge about the exact molecular mechanisms involved in the interactions among these protein and other molecular chaperones is still incomplete.ConclusionsOur investigation reports, for the first time, the expression patterns of HSP27 in human scalp skin and HF. The differential expression of HSP27 during HF cycling suggests its possible roles in human HF biology.