Increased synthesis of calcitonin gene-related peptide stimulates keratinocyte proliferation in murine UVB-irradiated skin.
Repeated ultraviolet (UV) irradiations have been shown to induce keratinocyte proliferation with acanthosis, stimulate the cutaneous nerve proliferation, and increase the synthesis of calcitonin gene-related peptide (CGRP). In the current study, we examined the role of CGRP in the UVB-induced proliferation of murine keratinocytes. UVB irradiation increased the number of bromodeoxyuridine (BrdU)-labeled basal keratinocytes and caused acanthosis. In addition, CGRP expression was up-regulated in the peripheral nerves of the upper dermis and lower epidermis. Repeated intradermal injections of CGRP increased the number of BrdU-labeled basal cells and caused acanthosis. Intradermal injections of capsaicin prior to UVB-irradiation inhibited the UVB-induced CGRP expression, BrdU labeling in basal keratinocytes and epidermal thickening. Intradermal injections of anti-CGRP antibody inhibited the UVB-induced BrdU labeling in basal keratinocytes, but epidermal thickening was not significantly inhibited. These results indicate that CGRP is one of the stimulators to UVB-induced keratinocyte proliferation. On the other hand, expression of substance P, another neuropeptide in the peripheral nerve, was not up-regulated by UVB irradiation.
Seike
Masahiro
M
Department of Dermatology, Kochi Medical School, Okohcho, Nankoku, 783-8505, Kochi, Japan. seikema@med.kochi-ms.ac.jp
Ikeda
Mitsunori
M
Morimoto
Akane
A
Matsumoto
Masaaki
M
Kodama
Hajime
H
D000818:Animals; D001973:Bromodeoxyuridine / Q000378:metabolism; D015740:Calcitonin Gene-Related Peptide / Q000096:biosynthesis*; D002211:Capsaicin / Q000494:pharmacology; D002455:Cell Division / Q000502:physiology / Q000528:radiation effects; D006965:Hyperplasia; D015603:Keratinocytes / Q000166:cytology / Q000378:metabolism* / Q000528:radiation effects*; D051379:Mice; D008807:Mice, Inbred BALB C; D013373:Substance P / Q000378:metabolism; D014466:Ultraviolet Rays / Q000009:adverse effects
D013373:Substance P; D001973:Bromodeoxyuridine; D015740:Calcitonin Gene-Related Peptide; D002211:Capsaicin