MiRNA-148b targeted AMPKα1 mediates high glucose-induced apoptosis in human renal tubular epithelial cells via oxidative stress / 中华肾脏病杂志

Objective To investigate the expression and mechanism of microRNA-148b (miRNA-148b) in high glucose-induced renal tubular injury.Method HK-2 cells cultured in vitro were divided into normal glucose group,mannitol hypertonic control group and high glucose group.After 48 hours of culture,the expression of miRNA-148b was detected by real-time quantitative PCR.2',7'-Dichlorodihydrofluorescein diacetate (DCFH-DA) was used for detecting production of ROS and observed under fluorescence microscope for analysis;The expression of AMPKot1,Bcl-2,NOX2,NOX4,activated caspase3 (cleaved-caspase3) were detected by Western blotting.Results Compared with the normal glucose group,the expression of miRNA-148b was up-regulated in HK-2 cells in high glucose group and hypertonic group (P ＜ 0.01),and the production of ROS increased (P ＜ 0.01).The expression of NOX2 and NOX4 was increased,AMPKα1 and Bcl-2 decreased,and cleaved caspase-3 was increased (all P ＜ 0.01).Conclusions HG up-regulated miRNA-148b expression and down-regulated its target gene AMPKα1 which promotes the expression of NOX2 and NOX4 in HK-2 cells.MiRNA-148b promotes apoptosis of HK-2 cells via increasing production of ROS and enhancing cleaved-caspase3 for Bcl-2 insufficiency.The tubular toxicity of high glucose is partly due to osmotic pressure.MiRNA-148b may be involved in the pathological injury of diabetic nephropathy and is expected to become a new therapeutic target for diabetic nephropathy.

The activation of α₂-adrenergic receptor in the spinal cord lowers sepsis-induced mortality

The effect of clonidine administered intrathecally (i.t.) on the mortality and the blood glucose level induced by sepsis was examined in mice. To produce sepsis, the mixture of D-galactosamine (GaLN; 0.6 g/10 ml)/lipopolysaccharide (LPS; 27 µg/27 µl) was treated intraperitoneally (i.p.). The i.t. pretreatment with clonidine (5 µg/5 µl) increased the blood glucose level and attenuated mortality induced by sepsis in a dose-dependent manner. The i.t. post-treatment with clonidine up to 3 h caused an elevation of the blood glucose level and protected sepsis-induced mortality, whereas clonidine post-treated at 6, 9, or 12 h did not affect. The pre-treatment with oral D-glucose for 30 min prior to i.t. post-treatment (6 h) with clonidine did not rescue sepsis-induced mortality. In addition, i.t. pretreatment with pertussis toxin (PTX) reduced clonidine-induced protection against mortality and clonidine-induced hyperglycemia, suggesting that protective effect against sepsis-induced mortality seems to be mediated via activating PTX-sensitive G-proteins in the spinal cord. Moreover, pretreatment with clonidine attenuated the plasma tumor necrosis factor α (TNF-α) induced by sepsis. Clonidine administered i.t. or i.p. increased p-AMPKα1 and p-AMPKα2, but decreased p-Tyk2 and p-mTOR levels in both control and sepsis groups, suggesting that the up-regulations of p-AMPKα1 and p-AMPKα2, or down-regulations of p-mTOR and p-Tyk2 may play critical roles for the protective effect of clonidine against sepsis-induced mortality.