UVA light stimulates the production of cathepsin G and elastase-like enzymes by dermal fibroblasts: a possible contribution to the remodeling of elastotic areas in sun-damaged skin.
Solar elastosis is characterized by accumulation of large amounts of material staining similarly to elastin in the dermis. The nature of this material and the process responsible for its accumulation are still unknown. Elastolytic proteases have important functions in the catabolism of the interstitial matrix and can also generate, by the digestion of the interstitial proteins, soluble peptides which can induce collagen and elastin synthesis and deposition. We investigated whether (i) elastolytic enzymes can be detected in samples from sun-exposed and non-exposed skin, and (ii) ultraviolet (UV) rays influence the production of elastolytic activities in cultured dermal fibroblasts. Immunoelectron microscopy showed a positive reaction for neutrophil elastase and cathepsin G in fibroblast-like cells from specimens of sun-exposed areas. Little or no reaction was found in biopsies of sun-protected skin. Fibroblast cultures from sun-exposed skin expressed higher levels of hydrolytic activity against synthetic substrates of elastases and cathepsin G than those obtained from sun-protected areas. Irradiation with UVA strongly stimulated the production of these activities in fibroblasts from sun-protected sites. No significant change was detected in parallel sets of cultures after UVB irradiation. Inhibition experiments indicated that the elastase-like activity expressed by fibroblasts can be attributed to at least two enzymes.
Cavarra
Eleonora
E
Dipartimento di Fisiopatologia e Medicina Sperimentale, University of Siena, Italy.
Fimiani
Michele
M
Lungarella
Giuseppe
G
Andreassi
Lucio
L
de Santi
Margherita
M
Mazzatenta
Carlo
C
Ciccoli
Lucia
L
D000368:Aged; D000369:Aged, 80 and over; D001706:Biopsy; D056649:Cathepsin G; D002403:Cathepsins / Q000096:biosynthesis / Q000528:radiation effects*; D018929:Cell Culture Techniques; D004790:Enzyme Induction / Q000528:radiation effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005347:Fibroblasts / Q000378:metabolism* / Q000528:radiation effects; D006801:Humans; D019272:Leukocyte Elastase / Q000096:biosynthesis / Q000528:radiation effects; D010196:Pancreatic Elastase / Q000096:biosynthesis / Q000528:radiation effects*; D012697:Serine Endopeptidases; D012867:Skin / Q000166:cytology / Q000528:radiation effects; D014466:Ultraviolet Rays / Q000009:adverse effects*
D004791:Enzyme Inhibitors; D002403:Cathepsins; D012697:Serine Endopeptidases; C534094:CTSG protein, human; D056649:Cathepsin G; D010196:Pancreatic Elastase; D019272:Leukocyte Elastase