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Corticotropin expression by human melanocytes in the skin
1Institute of Pathology (ICMR), New Delhi, India.
Pigment Cell Research
|June 1, 1995
Summary
Adrenocorticotropic hormone (ACTH) is expressed by melanocytes in human skin, particularly during UV exposure and in conditions like vitiligo and melanoma. This indicates a link between UV-dependent pigmentation and pro-opiomelanocortin (POMC) production.
Area of Science:
- Dermatology
- Cell Biology
- Endocrinology
Background:
- Highly dendritic melanocytes are found in various skin conditions, including seborrheic keratosis, melanoma, and vitiligo.
- Pro-opiomelanocortin (POMC) and its derivative ACTH (adrenocorticotropic hormone) are involved in pigmentation processes.
Purpose of the Study:
- To investigate the expression of ACTH in melanocytes within different skin contexts.
- To explore the role of ACTH and POMC in UV-induced pigmentation and vitiligo.
Main Methods:
- Immunohistochemical staining for ACTH using monoclonal antibodies on skin samples.
- Organ culture of vitiligo patient skin with varying treatments (dark incubation, adriamycin, UV exposure).
Main Results:
- Melanocytes in seborrheic keratosis, melanoma epidermis, and melanoma showed cytoplasmic ACTH positivity.
- Vitiligo skin cultures demonstrated increased ACTH-positive melanocytes after adriamycin and UV treatment.
- ACTH expression was localized to melanocytes in the G2-phase, enhanced by UV exposure.
Conclusions:
- ACTH is expressed by human skin melanocytes, with increased activity linked to UV exposure.
- UV-dependent pigmentation is associated with POMC production in the skin.
- The melanocyte network regulates MSH/ACTH levels locally, correlating with skin repigmentation and depigmentation in vitiligo, and is related to melanocyte UV sensitivity.