BACKGROUND： This study aimed to explore the effects of TNF-α on the expression of IP3R1 mRNA and protein in human mesangial cells （HMCs）, and to elucidate the mechanism of TNF-α relating to IP3R1 expression in th...BACKGROUND： This study aimed to explore the effects of TNF-α on the expression of IP3R1 mRNA and protein in human mesangial cells （HMCs）, and to elucidate the mechanism of TNF-α relating to IP3R1 expression in the occurrence of hepatorenal syndrome （HRS）.METHODS： HMCs were stimulated by tumor （TNF-α） with 100 ng/mL for different hours （2, 4, 8, and 24 hours）. The expression changes of IP3R1 mRNA and protein were detected by quantitative real-time polymerase chain reaction and immunoblotting. Several inhibitors including D609, U73122, PP1, safingol, rottlerin and non-radioactive protein kinase C （PKC） were used to examine the mechanism of signal transduction of TNF-α-regulated IP3R1 in HMCs.RESULTS： The levels of IP3R1 mRNA at 2 hours after TNF-α exposure were significantly enhanced and peaked at 8 hours in HMCs （P〈0.01）, then descended at 24 hours （P〈0.01）. The levels of IP3R1 protein at 4 hours after TNF-α exposure were obviously increased and peaked at 24 hours after TNF-α exposure （P〈0.01）. Compared to the control group, safingol （PKCa inhibitor） and D609 （phosphatidylcholine-specific phospholipase C inhibitor） significantly blocked the TNF-α- induced expression of IP3R1 mRNA （3.30±0.81 vs. 1.95±0.13, P〈0.05; 2.10±0.49, P〈0.01） and IP3R1 protein （3.09±0.13 vs. 1.86±0.39, P〈0.01; 1.98±0.02, P〈0.01）. TNF-α promoted PKCa activation with maximal PKCa phosphorylation that occurred 8 hours after stimulation measured by non-radioactive PKC assay, and the effect was markedly attenuated by pretreatment with D609 or safingol.CONCLUSION： TNF-α increased the expression of IP3R1 and this was mediated, at least in part, through the PC-PLC/PKCa signaling pathways in HMCs.展开更多
基金supported by a grant from Health Bureauof Jiangxi Province
文摘BACKGROUND： This study aimed to explore the effects of TNF-α on the expression of IP3R1 mRNA and protein in human mesangial cells （HMCs）, and to elucidate the mechanism of TNF-α relating to IP3R1 expression in the occurrence of hepatorenal syndrome （HRS）.METHODS： HMCs were stimulated by tumor （TNF-α） with 100 ng/mL for different hours （2, 4, 8, and 24 hours）. The expression changes of IP3R1 mRNA and protein were detected by quantitative real-time polymerase chain reaction and immunoblotting. Several inhibitors including D609, U73122, PP1, safingol, rottlerin and non-radioactive protein kinase C （PKC） were used to examine the mechanism of signal transduction of TNF-α-regulated IP3R1 in HMCs.RESULTS： The levels of IP3R1 mRNA at 2 hours after TNF-α exposure were significantly enhanced and peaked at 8 hours in HMCs （P〈0.01）, then descended at 24 hours （P〈0.01）. The levels of IP3R1 protein at 4 hours after TNF-α exposure were obviously increased and peaked at 24 hours after TNF-α exposure （P〈0.01）. Compared to the control group, safingol （PKCa inhibitor） and D609 （phosphatidylcholine-specific phospholipase C inhibitor） significantly blocked the TNF-α- induced expression of IP3R1 mRNA （3.30±0.81 vs. 1.95±0.13, P〈0.05; 2.10±0.49, P〈0.01） and IP3R1 protein （3.09±0.13 vs. 1.86±0.39, P〈0.01; 1.98±0.02, P〈0.01）. TNF-α promoted PKCa activation with maximal PKCa phosphorylation that occurred 8 hours after stimulation measured by non-radioactive PKC assay, and the effect was markedly attenuated by pretreatment with D609 or safingol.CONCLUSION： TNF-α increased the expression of IP3R1 and this was mediated, at least in part, through the PC-PLC/PKCa signaling pathways in HMCs.
