Granuloma collagenase and EDTA-sensitive neutral protease production in hepatic murine schistosomiasis.
Mice infected with Schistosoma mansoni represent a model for study of hepatic fibrosis in humans. Production of trypsin-activatable inactive collagenase and EDTA-sensitive neutral protease was measured in the culture medium in which granuloma explants or primary cultures were maintained. Collagenase production was maximal in granulomas obtained from liver of mice 8 weeks postinfection and was inhibited by Actinomycin D or cycloheximide, and enhanced by lymphocyte factor(s) or heparin. Isolated schistosome eggs did not release these enzymatic activities but did release EDTA-insensitive protease activity. Both enzymes were separated by ion-exchange chromatography and purified to homogeneity. Isolated collagenase had an isoelectric point of 6.2 and molecular weight of 60,000 and had the functional characteristics of a tissue collagenase. The specific activity of collagenase was 33 units per mg protein at an optimum pH 7.5 and lacked proteolytic activity against noncollagenous protein substrates. Isolated EDTA-sensitive neutral protease had specific caseinolytic activity of 150 units per mg protein and gelatinolytic activity of 300 units per mg protein at an optimum pH 7.5; the enzyme lacked activity against undenatured collagen. Isoelectric point was pH 6.0. Protease activity was inhibited by known inhibitors of collagenases. Production and activation of EDTA-sensitive neutral protease and collagenase accompany increased collagen synthesis and content in the liver of mice 8 weeks postinfection with S. mansoni cercariae. Continued accumulation of liver collagen under these conditions suggests an insufficiency in collagenase activity relative to the increase in collagen synthesis.
D000818:Animals; D003094:Collagen / Q000096:biosynthesis; D046508:Culture Techniques; D004492:Edetic Acid / Q000378:metabolism; D006099:Granuloma / Q000201:enzymology*; D006863:Hydrogen-Ion Concentration; D007526:Isoelectric Point; D008099:Liver / Q000378:metabolism; D008109:Liver Diseases, Parasitic / Q000201:enzymology*; D051379:Mice; D003012:Microbial Collagenase / Q000378:metabolism*; D010447:Peptide Hydrolases / Q000378:metabolism*; D012550:Schistosoma mansoni; D012552:Schistosomiasis / Q000201:enzymology*
D003094:Collagen; D004492:Edetic Acid; D010447:Peptide Hydrolases; D003012:Microbial Collagenase