cAMP-mediated upregulation of gelatinases in primary cultures of isolated rat hepatocytes.
Matrix metalloproteinases (MMPs) play a major role in tissue remodelling and repair in pathophysiological conditions, such as liver fibrosis and regeneration. Regulation of the MMPs produced by liver cells is important in maintaining cell-matrix ratio in liver, which is a major target site for hormones that mediate their intracellular effects through cAMP. The possibility of cAMP affecting the activity of MMPs and their endogenous inhibitors, tissue inhibitor of MMPs (TIMPs) was studied using isolated rat hepatocytes in culture. Zymographic analysis showed that treatment with hormones like epinephrine, thyroxine and dexamethasone and Bt2 cAMP increased 92 kDa MMP-9 activity. Bt2 cAMP caused upregulation of MMP-9 in a dose-dependent manner. The effect of hormones was less on MMP-2. ELISA using specific antibodies showed increase in levels of MMP-9 and TIMP-1 protein. Kinetic analysis of production of MMPs and TIMPs showed that the response to Bt2 cAMP was a delayed one, indicating its effect on de novo protein synthesis. These results suggest the possibility of cAMP dependent regulation of MMP-9 in the hepatocytes.
Department of Biochemistry, University of Kerala, Kariavattom, Thiruvananthapuram 695581, India.
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K
Saja
P R
PR
Sudhakaran
D000818:Animals; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005109:Extracellular Matrix / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic; D022781:Hepatocytes / Q000201:enzymology*; D006735:Horseradish Peroxidase / Q000378:metabolism; D007700:Kinetics; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism; D020782:Matrix Metalloproteinases / Q000096:biosynthesis*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors; D015854:Up-Regulation
D000242:Cyclic AMP; D006735:Horseradish Peroxidase; D020782:Matrix Metalloproteinases; D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9