title: Rapamycin at subimmunosuppressive levels inhibits mesangial cell proliferation and extracellular matrix production.
abstract: In view of its proven antiproliferative effects, rapamycin offers potential in the treatment of mesangioproliferative disease. Previous data have shown an effect of rapamycin on mesangial cell proliferation at high doses and have not explored the mechanism of action. Therefore, we explored the effects and mechanism of action of low levels of rapamycin on mesangial cell proliferation. Primary cultures of mouse mesangial cells were grown in medium containing serum with differing concentrations of rapamycin. A rapamycin concentration of 0.1 ng/ml caused a decrease in cell number and DNA synthesis with no effect on apoptosis. Type IV collagen protein production was inhibited at 0.01 ng/ml rapamycin, although gene expression was unaffected. P70S6K phosphorylation was inhibited in parallel with the effects on cell number and DNA synthesis in a dose-dependent manner, but no effect was seen at 0.01 ng/ml rapamycin. These data show an effect on mesangial cell proliferation and p70S6 kinase phosphorylation of 0.1 ng/ml rapamycin and an effect on collagen IV production of 0.01 ng/ml rapamycin. We suggest that further in vivo studies should explore the potential for low-dose rapamycin in the treatment of mesangioproliferative glomerulonephritis.
authors.affiliation: Department of Nephrology and Transplantation, King's College London School of Medicine, London, United Kingdom.
authors.forename: Helen R
authors.initials: HR
authors.lastname: Lock
authors.forename: Steven H
authors.initials: SH
authors.lastname: Sacks
authors.forename: Michael G
authors.initials: MG
authors.lastname: Robson
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D015153:Blotting, Western; D002452:Cell Count; D049109:Cell Proliferation / Q000187:drug effects; D002469:Cell Separation; D002470:Cell Survival / Q000187:drug effects; D024141:Collagen Type IV / Q000096:biosynthesis; D003124:Colorimetry; D004305:Dose-Response Relationship, Drug; D005109:Extracellular Matrix / Q000187:drug effects* / Q000648:ultrastructure; D047468:Immunoprecipitation; D007166:Immunosuppressive Agents / Q000494:pharmacology*; D020287:In Situ Nick-End Labeling; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D050527:Mesangial Cells / Q000166:cytology* / Q000187:drug effects* / Q000648:ultrastructure; D051379:Mice; D008810:Mice, Inbred C57BL; D010766:Phosphorylation; D020133:Reverse Transcriptase Polymerase Chain Reaction; D038762:Ribosomal Protein S6 Kinases, 70-kDa / Q000378:metabolism; D020123:Sirolimus / Q000494:pharmacology*; D013936:Thymidine / Q000378:metabolism
chemical_list: D024141:Collagen Type IV; D007166:Immunosuppressive Agents; D007770:L-Lactate Dehydrogenase; D038762:Ribosomal Protein S6 Kinases, 70-kDa; D013936:Thymidine; D020123:Sirolimus