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Differential expression of nitric oxide synthases in human scalp epidermal and hair follicle pigmentary units: implications for regulation of melanogenesis.
Br J Dermatol. 2005 Aug; 153(2):301-9.BJ

Abstract

BACKGROUND

Nitric oxide (NO) is a ubiquitous gaseous lipophilic molecule generated from the conversion of L-arginine to L-citrulline by the NO synthases (NOSs). Ultraviolet radiation (UVR)-induced NO production appears to stimulate epidermal melanogenesis. However, given their relative protection from UVR, it is unclear whether NO plays a similar role in hair bulb melanocytes.

OBJECTIVES

We aimed to identify the expression profiles of the NOS isoforms endothelial NOS (eNOS), neuronal NOS (nNOS) and inducible NOS (iNOS) and of phosphorylated eNOS and nitrotyrosine within the epidermal and follicular melanin units of normal human haired scalp during the hair growth cycle.

METHODS

This study employed single and double immunohistochemical and immunofluorescence staining techniques using haired scalp from 10 healthy individuals (six women and four men).

RESULTS

Melanocytes in the basal layer of the epidermis expressed eNOS, nNOS and nitrotyrosine. By contrast, melanogenically active melanocytes of the anagen hair bulb were wholly negative for these markers. However, other follicular melanocytes not actively involved in pigment production, including undifferentiated melanocytes located in the outer root sheath and melanocytes surviving the apoptosis-driven hair follicle (HF) regression during catagen/telogen, expressed eNOS, nNOS and nitrotyrosine. While iNOS was only weakly expressed in the basal layer of the human epidermis, it was highly expressed in keratinocytes of the inner root sheath (IRS), where it colocalized with trichohyalin, a differentiation-associated protein of the IRS that requires enzyme-catalysed conversion of arginine to citrulline.

CONCLUSIONS

The NOS isoforms and nitrotyrosine are differentially expressed in different cutaneous melanocyte subpopulations. Results of this study suggest a possible role for eNOS, nNOS, iNOS and nitrotyrosine in melanocyte biology, particularly with respect to melanogenesis and melanocyte survival during HF regression. Another example of possible NO involvement in HF biology is the postsynthetic modification of trichohyalin in differentiating keratinocytes of the IRS. These results suggest that NO may influence several aspects of HF biology.

Authors+Show Affiliations

Department of Biomedical Sciences, School of Life Sciences, University of Bradford, Bradford BD7 1DP, UK.No affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

16086740

Citation

Sowden, H M., et al. "Differential Expression of Nitric Oxide Synthases in Human Scalp Epidermal and Hair Follicle Pigmentary Units: Implications for Regulation of Melanogenesis." The British Journal of Dermatology, vol. 153, no. 2, 2005, pp. 301-9.
Sowden HM, Naseem KM, Tobin DJ. Differential expression of nitric oxide synthases in human scalp epidermal and hair follicle pigmentary units: implications for regulation of melanogenesis. Br J Dermatol. 2005;153(2):301-9.
Sowden, H. M., Naseem, K. M., & Tobin, D. J. (2005). Differential expression of nitric oxide synthases in human scalp epidermal and hair follicle pigmentary units: implications for regulation of melanogenesis. The British Journal of Dermatology, 153(2), 301-9.
Sowden HM, Naseem KM, Tobin DJ. Differential Expression of Nitric Oxide Synthases in Human Scalp Epidermal and Hair Follicle Pigmentary Units: Implications for Regulation of Melanogenesis. Br J Dermatol. 2005;153(2):301-9. PubMed PMID: 16086740.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Differential expression of nitric oxide synthases in human scalp epidermal and hair follicle pigmentary units: implications for regulation of melanogenesis. AU - Sowden,H M, AU - Naseem,K M, AU - Tobin,D J, PY - 2005/8/10/pubmed PY - 2005/10/27/medline PY - 2005/8/10/entrez SP - 301 EP - 9 JF - The British journal of dermatology JO - Br J Dermatol VL - 153 IS - 2 N2 - BACKGROUND: Nitric oxide (NO) is a ubiquitous gaseous lipophilic molecule generated from the conversion of L-arginine to L-citrulline by the NO synthases (NOSs). Ultraviolet radiation (UVR)-induced NO production appears to stimulate epidermal melanogenesis. However, given their relative protection from UVR, it is unclear whether NO plays a similar role in hair bulb melanocytes. OBJECTIVES: We aimed to identify the expression profiles of the NOS isoforms endothelial NOS (eNOS), neuronal NOS (nNOS) and inducible NOS (iNOS) and of phosphorylated eNOS and nitrotyrosine within the epidermal and follicular melanin units of normal human haired scalp during the hair growth cycle. METHODS: This study employed single and double immunohistochemical and immunofluorescence staining techniques using haired scalp from 10 healthy individuals (six women and four men). RESULTS: Melanocytes in the basal layer of the epidermis expressed eNOS, nNOS and nitrotyrosine. By contrast, melanogenically active melanocytes of the anagen hair bulb were wholly negative for these markers. However, other follicular melanocytes not actively involved in pigment production, including undifferentiated melanocytes located in the outer root sheath and melanocytes surviving the apoptosis-driven hair follicle (HF) regression during catagen/telogen, expressed eNOS, nNOS and nitrotyrosine. While iNOS was only weakly expressed in the basal layer of the human epidermis, it was highly expressed in keratinocytes of the inner root sheath (IRS), where it colocalized with trichohyalin, a differentiation-associated protein of the IRS that requires enzyme-catalysed conversion of arginine to citrulline. CONCLUSIONS: The NOS isoforms and nitrotyrosine are differentially expressed in different cutaneous melanocyte subpopulations. Results of this study suggest a possible role for eNOS, nNOS, iNOS and nitrotyrosine in melanocyte biology, particularly with respect to melanogenesis and melanocyte survival during HF regression. Another example of possible NO involvement in HF biology is the postsynthetic modification of trichohyalin in differentiating keratinocytes of the IRS. These results suggest that NO may influence several aspects of HF biology. SN - 0007-0963 UR - https://www.unboundmedicine.com/medline/citation/16086740/Differential_expression_of_nitric_oxide_synthases_in_human_scalp_epidermal_and_hair_follicle_pigmentary_units:_implications_for_regulation_of_melanogenesis_ L2 - https://doi.org/10.1111/j.1365-2133.2005.06718.x DB - PRIME DP - Unbound Medicine ER -