Molecular mechanisms of photoaging in human skin in vivo and their prevention by all-trans retinoic acid.
Solar UV radiation damages human skin, affecting skin tone and resiliency and leading to premature aging (photoaging), the symptoms of which include leathery texture, wrinkles, mottled pigmentation, laxity and sallowness. We propose that photoaging results largely from UV induction of matrix metalloproteinases (MMP) that degrade skin collagen. We find that pretreatment of human skin with all-trans retinoic acid (tRA) inhibits UV induction of MMP, suggesting that tRA can protect against UV-induced collagen destruction and may therefore be able to lessen the effects of photoaging. The tRA prevents UV-induced accumulation of c-Jun protein, which is required for MMP gene expression. Activation of c-Jun transcriptional activity requires N-terminal phosphorylation. The majority of c-Jun in human skin in vivo is N-terminal phosphorylated. Topically applied tRA does not inhibit N-terminal phosphorylation by UV-induced c-Jun kinase activity in human skin. The tRA likely acts to reduce UV induction of c-Jun protein by stimulating its breakdown through the ubiquitin-proteasome pathway.
Department of Dermatology, University of Michigan, Ann Arbor, USA. dianemch@umich.edu
G J
GJ
Fisher
H S
HS
Talwar
J
J
Lin
J J
JJ
Voorhees
D000328:Adult; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism; D006801:Humans; D007641:Keratolytic Agents / Q000627:therapeutic use*; D008666:Metalloendopeptidases / Q000378:metabolism; D016755:Proto-Oncogene Proteins c-jun / Q000378:metabolism; D015398:Signal Transduction; D012867:Skin / Q000201:enzymology / Q000473:pathology / Q000528:radiation effects; D015595:Skin Aging / Q000187:drug effects*; D018808:Transcription Factor AP-1 / Q000378:metabolism; D014212:Tretinoin / Q000627:therapeutic use*; D014466:Ultraviolet Rays
D007641:Keratolytic Agents; D016755:Proto-Oncogene Proteins c-jun; D018808:Transcription Factor AP-1; D014212:Tretinoin; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D008666:Metalloendopeptidases