In vitro prevention of cyclosporin-induced cell contraction by mycophenolic acid.
Nephrotoxicity is a major side-effect of cyclosporin A (CsA), which induces a vasoconstrictive response in vascular smooth muscle and mesangial cells. Mycophenolic acid (MPA) is used in combination with low-dose CsA to reduce nephrotoxicity. We previously demonstrated that MPA affected mesangial cell contractile response to angiotensin II or KCl. Aims of the present study were to evaluate if MPA can prevent CsA-induced contraction of human mesangial and aortic smooth muscle cells (ASMC). Using a morphoquantitative approach, we evidenced that pretreatment with MPA (1 microM) prevented the reduction of cell area induced by CsA within 30 min in both cell types. We then compared the expression of three main cytoskeleton proteins: tubulin, alpha-smooth actin (SMA) and basic calponin, in ASMC and in mesangial cells treated with MPA and/or CsA. CsA alone did not significantly change the expression level of these proteins neither in mesangial cells nor in ASMC. MPA decreased the expression level of tubulin in both mesangial cells and ASMC. Surprisingly, MPA, which stimulated SMA and calponin expression in mesangial cells, exerted an inhibitory effect on both contractile protein expression in ASMC. In conclusion, our results evidenced opposite effects of MPA on calponin and SMA protein expression in ASMC and in mesangial cells, despite similar antiproliferative properties, suggesting that sarcomeric protein expression is controlled by different intracellular mechanisms in mesangial and smooth muscle cells. However, MPA interferes in both cell types with the constrictive properties CsA, which may partially explain the protective effects of MPA against CsA nephrotoxicity.
GREF/INSERM E362, Université Bordeaux2, Bordeaux, France. dubus@biophar.u-bordeaux2.fr
Isabelle
I
Dubus
Sandra
S
Sena
Jean-Pierre
JP
Labouyrie
Jacques
J
Bonnet
Christian
C
Combe
D000199:Actins / Q000096:biosynthesis; D000903:Antibiotics, Antineoplastic / Q000009:adverse effects / Q000494:pharmacology*; D001011:Aorta / Q000166:cytology / Q000378:metabolism*; D002135:Calcium-Binding Proteins / Q000096:biosynthesis; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects; D016572:Cyclosporine / Q000009:adverse effects / Q000494:pharmacology*; D004336:Drug Antagonism; D005786:Gene Expression Regulation / Q000187:drug effects; D005920:Glomerular Mesangium / Q000166:cytology / Q000378:metabolism*; D006801:Humans; D007166:Immunosuppressive Agents / Q000009:adverse effects / Q000494:pharmacology*; D008840:Microfilament Proteins; D009173:Mycophenolic Acid / Q000009:adverse effects / Q000494:pharmacology*; D032389:Myocytes, Smooth Muscle / Q000378:metabolism*; D014176:Protein Biosynthesis / Q000187:drug effects; D014404:Tubulin / Q000096:biosynthesis; D014661:Vasoconstriction / Q000187:drug effects; D000096985:Calponins
D000199:Actins; D000903:Antibiotics, Antineoplastic; D002135:Calcium-Binding Proteins; D016572:Cyclosporine; D007166:Immunosuppressive Agents; D008840:Microfilament Proteins; D009173:Mycophenolic Acid; D014404:Tubulin; D000096985:Calponins