In:
British Journal of Pharmacology, Wiley, Vol. 172, No. 13 ( 2015-07), p. 3434-3445
Kurzfassung:
cAMP as a second messenger stimulates expression of microphthalmia‐associated transcription factor ( MITF ) or the tyrosinase gene in UVB ‐induced skin pigmentation. Diphenylmethylene hydrazinecarbothioamide ( QNT 3‐80) inhibits α‐melanocyte‐stimulating hormone (α‐ MSH )‐induced melanin production in B 16 murine melanoma cells but its molecular basis remains to be defined. Here, we investigated the mechanism underlying the amelioration of skin hyperpigmentation by QNT 3‐80. Experimental Approach We used melanocyte cultures with raised levels of cAMP and UVB ‐irradiated dorsal skin of guinea pigs for pigmentation assays. Immunoprecipitation, kemptide phosphorylation, fluorescence analysis and docking simulation were applied to elucidate a molecular mechanism of QNT 3‐80. Key Results QNT 3‐80 inhibited melanin production in melanocyte cultures with elevated levels of cAMP , including those from human foreskin. This compound also ameliorated hyperpigmentation in vivo in UVB ‐irradiated dorsal skin of guinea pigs. As a mechanism, QNT 3‐80 directly antagonized cAMP binding to the regulatory subunit of PKA , nullified the dissociation and activation of inactive PKA holoenzyme in melanocytes and fitted into the cAMP ‐binding site on the crystal structure of human PKA under the most energetically favourable simulation. QNT 3‐80 consequently inhibited cAMP ‐ or UVB ‐induced phosphorylation (activation) of cAMP ‐responsive element‐binding protein in vitro and in vivo , thus down‐regulating expression of genes for MITF or tyrosinase in the melanogenic process. Conclusions and Implications Our data suggested that QNT 3‐80 could contribute significantly to the treatment of skin disorders with hyperpigmented patches with the cAMP ‐binding site of PKA as its molecular target.
Materialart:
Online-Ressource
ISSN:
0007-1188
,
1476-5381
DOI:
10.1111/bph.2015.172.issue-13
Sprache:
Englisch
Verlag:
Wiley
Publikationsdatum:
2015
ZDB Id:
2029728-2
SSG:
15,3
