Subject(s)
Cathepsins/metabolism , Enzyme Precursors/metabolism , Fibroblasts/enzymology , Fibronectins/metabolism , Matrix Metalloproteinase 1/metabolism , Peptide Fragments/metabolism , Serine Endopeptidases/metabolism , Skin/enzymology , Adult , Age Factors , Aged , Aging , Buttocks , Cathepsin G , Cathepsins/antagonists & inhibitors , Cells, Cultured , Enzyme Activation , Female , Fibroblasts/drug effects , Fibroblasts/radiation effects , Humans , Male , Matrix Metalloproteinase 1/genetics , Matrix Metalloproteinase 2/metabolism , Middle Aged , RNA, Messenger/metabolism , Serine Proteinase Inhibitors/pharmacology , Skin/cytology , Skin/drug effects , Skin/radiation effects , Ultraviolet RaysABSTRACT
Alpha-ketoglutarate is a key intermediate in the Krebs cycle, and a rate-limiting cofactor of prolyl-4-hydroxylase. It also has a potent effect on increasing the proline pool during collagen production, but the details underlying the boosting effect on collagen production by alpha-ketoglutarate remain as yet unreported. To investigate the effects of alpha-ketoglutarate on procollagen production and wrinkle formation, we conducted experiments in cultured human dermal fibroblasts and UVB-irradiated hairless mice. Based on ELISA measurements, alpha-ketoglutarate (10 microM) stimulated procollagen production in fibroblasts by 25.6+/-4.6% compared to vehicle (dH(2)O)-treated control cells. Also, we demonstrated that alpha-ketoglutarate increased activities of prolidase, which is known to play an important role in collagen metabolism, in fibroblasts and N-benzyloxycarbonyl-L-proline (Cbz-Pro), prolidase inhibitor, inhibited procollagen synthesis by alpha-ketoglutarate in fibroblasts. To determine the effect of topically applied alpha-ketoglutarate on wrinkle formation, alpha-ketoglutarate (1%) and vehicle (70% propylene glycol, 30% ethanol) were applied on the dorsal skin of UVB-induced hairless mice for twelve weeks. We found that alpha-ketoglutarate decreased wrinkle formation upon long-term topical application. These results suggest that alpha-ketoglutarate diminishes UVB-induced wrinkle formation by increasing collagen production, through a pathway that involves prolidase activation. Therefore, application of alpha-ketoglutarate may represent an effective anti-wrinkle agent for the cosmetic field.