| 15729575 |
Artwohl M, Furnsinn C, Waldhausl W, Holzenbein T, Rainer G, Freudenthaler A, Roden M, Baumgartner-Parzer SM: Thiazolidinediones inhibit proliferation of microvascular and macrovascular cells by a PPARgamma-independent mechanism. Diabetologia. 2005 Mar;48(3):586-94. Epub 2005 Feb 24.
AIMS/HYPOTHESIS: This study evaluated the hypothesis that peroxisome proliferator-activated receptor-gamma (PPARgamma) agonists, including thiazolidinediones (TZDs) and the rexinoid LG100268 (LG), directly affect human vascular cell function (proliferation, cell cycle, protein expression, lactate release) independently of (1) their PPARgamma-activating potential and (2) the cells' vascular origin. METHODS: Human umbilical vein endothelial cells (HUVECs), human adult vein endothelial cells (HAVECs), human retinal endothelial cells (HRECs) and human retinal pericytes (HRPYCs) were incubated (48 h) with 2-50 micromol/l rosiglitazone (RSG), RWJ241947 (RWJ), pioglitazone (PIO), troglitazone (TRO), 15-deoxy-Delta (12,14)-prostaglandin J2 (PGJ2) and LG. Proliferation, cell cycle distribution, protein expression, peroxisome proliferator-activated receptor responsive element (PPRE) transcriptional activity and mitochondrial effects were determined by [3H] thymidine incorporation, FACS analyses, western blots, reporter assays and lactate release respectively. RESULTS: In HUVECs, RSG, RWJ, PIO, TRO, PGJ2 and LG reduced (p <0.01) proliferation (due to a G0/G1 cell cycle arrest) by up to 23%, 36%, 38%, 86%, 99% and 93% respectively. The antiproliferative response was similar in HRPYCs and HAVECs, but was attenuated in HRECs. Whereas p21WAF-1/Cip1 and p27Kip were differently affected in HUVECs, all agents reduced (p <0.05) expression of cyclins (D3, A, E, B), cyclin-dependent kinase-2 and hyperphosphorylated retinoblastoma protein. The rank order of the antiproliferative effects of TZDs in HUVECs (RSG approximately PIO approximately RWJ inhibition and lactate release were mimicked by rotenone (mitochondrial complex I inhibitor). CONCLUSIONS/INTERPRETATION: In conclusion, this study suggests that the antiproliferative action of the TZDs in vascular cells is independent of their PPARgamma-activating and associated insulin-sensitising potential, but could relate to mitochondrial mechanisms. |
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