ABSTRACT
AIM:To investigate the effects of silent information regulator 1 (SIRT1) on high glucose-induced acetylation of NF-κB p65 subunit and its protective role in rat mesangial cells .METHODS:Rat mesangial cells were cul-tured in DMEM supplemented with 10% FBS and were divided into control group , mannitol group , high glucose group , resveratrol group and SIRT1 RNAi group.The cell viability was determined by MTT assay .The mRNA expression of SIRT1, monocyte chemoattratant protein 1 (MCP-1), vascular cell adhesion molecule 1 (VCAM-1-1), tumor necrosis fac-torα( TNF-α) , transforming growth factor β1 ( TGF-β1 ) was analyzed by real-time quantitative PCR .The protein expres-sion of SIRT1 and the acetylation of NF-κB p65 subunit were determined by Western blotting .The protein concentrations of MCP-1, VCAM-1, TNF-α, TGF-β1 and malondialdehyde (MDA) were detected by ELISA.RESULTS:The cell viabili-ty, superoxide dismutase (SOD) activity, and the expression of SIRT1 at mRNA and protein levels were decreased by high glucose treatment as compared with control group .The acetylation of NF-κB p65 subunit was significantly increased after interfered with high glucose , resulting in the increase in the secretion of MCP-1, VCAM-1, TNF-αand TGF-β1 .Resvera-trol decreased high glucose-induced acetylation of NF-κB p65 subunit.However, silencing SIRT1 significantly enhanced the acetylation of NF-κB p65 subunit and the expression of MCP-1, VCAM-1, TNF-αand TGF-β1 .CONCLUSION:SIRT1 remarkably inhibits the inflammatory reactions by deacetylating NF-κB p65, suggesting that SIRT1 is a possible tar-get for preventing diabetic nephropathy .
ABSTRACT
Objective To observe the expression of axon guidance cues Slit2 and Robo4 in lung tissue of rat with acute lung injury (ALI) and explore the function of Slit2 and Robo4 in ALI.Methods Forty-eight Sprague-Dawley rats were randomly (random number) divided into control group (n =24) and ALl group (n =24).ALI model was reproduced by cecum ligation and puncture (CLP).The control group only experienced a simulated operation without CLP.Both groups were further divided into 3 subgroups with 8 rats in each subgroup:12 h,24 h,and 48 h subgroups.artery blood gas analysis,lung tissue wet/dry weight (W/D) ratio,lung histopathologic changes,pulmonary microvascular permeability were observed.The serum tumor nocrosis factor-α (TNF-α) was measured with enzyme linked immunosorbent assay (ELISA).The expression of Slit2 and Robo4 mRNA were detected by reverse transcription-polymerase chain reaction (RT-PCR).The expression of Slit2 and Robo4 protein in lung tissues was assessed by immunohistochemistry.Date were analyzed by one-way ANOVA with SPSS version 13.0 software.Statistical significance was established at a P value of less than 0.05.Results Compared with the control group,in ALI rats at different time points,partial pressure of oxygen in arterial blood (PaO2) decreased significantly,lung W/D weight ratio and pulmonary microvascular permeability,the serum TNF-α increased significantly (all P ＜ 0.05),histopathology of lung revealed signs of injury.The expression of Slit2 mRNA in lung tissues was decreased markedly after CLP compared with control group [(0.56±0.13) vs.(0.87±0.05),F=41.39,P＜0.05,(0.42±0.10) vs.(0.85±0.07),F=93.54,P＜0.05,(0.26±0.08) vs.(0.89 ±0.09),F=227.05,P＜0.05].but there were no significant difference in expression of Robo4 mRNA in lung tissue between ALI group and control group [(0.86±0.07) vs.(0.83±0.05),F=0.695,P＞0.05,(0.82±0.05) vs.(0.89±0.08),F=2.061,P ＞ 0.05,(0.86 ± 0.08) vs.(0.86 ± 0.05),F =0.035,P ＞ 0.05].Immunohistochemistry study showed Slit2 protein was mainly expressed on the extracellular surface of vascular endothelial cells,while lung epithelial cell nuclei and endochylema.Robo4 protein was only expressed on the extracellular surface of vascular endothelial cells.Compared with the control group,expression of Slit2 protein in lung tissue in ALI group decreased markedly [(0.37 ± 0.05) vs.(0.45 ± 0.07),F =6.82,P ＜ 0.05,(0.32±0.06) vs.(0.47±0.09),F=23.54,P＜0.05,(0.28±0.07) vs.(0.46±0.06),F=28.01,P ＜ 0.05].As good as RT-PCR,there were no significant difference in expression of Robo4 protein in lung tissue between two groups [(0.53±0.04) vs.(0.52±0.05),F=0.155,P＞0.05,(0.53± 0.09) vs.(0.50±0.05),F=0.498,P＞0.05,(0.55±0.06) vs.(0.56±0.07),F=0.073,P ＞ 0.05].Conclusions Lung tissues of control group rats express Slit2 and Robo4.The decreased Slit2 mRNA and protein expressions in the lung tissue of rat with ALI caused by CLP may be associated with the occurrence of ALI.