γ‐melanocyte stimulating hormone (γ‐MSH)‐like immunoreactivity is present in certain normal human keratinocytes

Abstract

Using the indirect immunohistochemical approach, the occurrence of gamma-melanocyte stimulating hormone (gamma-MSH)-like immunoreactivity in human normal keratinocytes is described. The positive cells were observed in each layer of the epidermis (except stratum corneum) and often, at the level of the stratum spinosum, also around the orifices of cutaneous accessory organs, such as sweat glands and sebaceous glands/hair follicles. Combining these data with our previous investigations, the results support the possibility that locally produced gamma-MSH could be involved in cutaneous immune response, pigmentation and epithelial proliferation, as well as neuromodulation.

Presence of immunoreactive β‐endorphin in human skin

“…As a result of the unpredictable formation of POMC peptides it is difficult to determine whether any detected POMC‐IR is indeed produced locally, or results from incorporation from the systemic circulation, nerve fibers, or infiltrating inflammatory cells (22, 24). Interpretation is further complicated by the inconsistency in the detection of POMC‐IR in benign and malignant skin disease (19, 23, 24, 33).…”

“…Thody (19) was the first to report αMSH‐like immunoreactivity (IR) in homogenates of human skin by means of radioimmunoassay (RIA), and more recently the same group identified by HPLC both αMSH and ACTH in normal human skin as well as in cultured keratinocytes (20). Furthermore, in normal human skin γMSH‐IR has been localized in keratinocytes, duct cells of sweat glands, nerves, and neutrophilic granulocytes using immunofluorescence (21, 22). βE‐ and ACTH‐immunostaining to keratinocytes of hair follicles was observed in scalp but not in corporal skin, as well as in diseased skin including naevi and melanoma, albeit only in approximately 60% of the samples (23, 24).…”

Cutaneous Immunomodulation and Coordination of Skin Stress Responses by α‐Melanocyte‐Stimulating Hormonea

“…γMSH‐like immunoreactivity has been reported in sensory skin nerves, neutrophils, and some keratinocyte subpopulations of human skin, which also displays β‐MSH immunoreactivity in selected epithelial regions of scalp hair follicles. 37–39 Additional POMC products have been detected in most cutaneous cell populations (Table 1). 9,40–42…”

“…Accordingly, metastatic melanoma can been associated with abnormally high melanotropin serum levels 42,44 and increased serum levels of POMC products like β‐endorphin have also been reported for inflammatory dermatoses like psoriasis and atopic eczema 45,46 as well as after skinexposure to UV light. 47,48 Although, some human epidermal keratinocyte populations may constitutively express γ‐MSH or β‐MSH in situ, 38,39 normal, unstimulated epidermal cells do not express significant quantities of POMC transcripts and release peptides like αMSH, but a significant upregulation has been observed following UV irradiation or stimulation with IL‐1. 9,35,36,49 Since UV light recently has been shown to upregulate the transcription of prohormone convertase 1 human keratinocytes in vitro, UV exposure may alter both cutaneous POMC transcription and the posttranslational processing of POMC peptides (Fig.…”

Towards a renaissance of dermatoendocrinology: Selected current frontiers

“…Beyond a conventional focus on steroid hormones, [9][10][11] early on, the journal has championed skin research into neuroendocrine signalling and non-steroid hormones. [12][13][14][15] Since the foundation of a working group within the Arbeitsgemeinschaft Dermatologische Forschung (ADF) devoted to dermatoendocrinology, its founders, Christos Zouboulis, Ralf Paus and Markus Böhm have been eager to promote research, stimulate scientific exchange and increase the overall visibility of this emerging field, for example by editing special supplemental issues of Experimental Dermatology. [16][17][18][19][20][21] This journal tradition of fostering (neuro-)endocrine research in investigative dermatology and skin biology has been carried on uninterruptedly into the present.…”