Toll样受体4通过PI3K/Akt信号通路调节骨髓间充质干细胞凋亡

Toll-like receptor 4 regulats apoptosis of bone marrow mesenchymal stem cells through PI3K/Akt signaling pathways

目的研究Toll样受体4(TLR4)对骨髓间充质干细胞(MSCs)凋亡的影响及其可能的机制。方法本实验运用脂多糖(LPS)作用于的大鼠MSCs,应用流式细胞术鉴定MSCs;实验分成4组:对照组、LPS组、TLR4阻断剂+LPS组、LY294002+LPS组,缺氧处理6h后,用Western blot法检测TLR4、p-Akt、Akt、Bax、Bcl2、Caspase-3蛋白的表达变化;流式细胞术检测细胞凋亡率。结果与对照组比较,LPS作用后TLR4的表达明显上调(P<0.01),p-Akt表达增加,Bax表达降低,Bcl-2的表达上升,Caspase-3表达减少,且MSCs的凋亡率也减少(P<0.05);TLR4阻断剂处理后p-Akt较LPS组减少,Bax表达上调,Bcl-2的表达下降,Caspase-3表达增加,MSCs的凋亡率也增加(P<0.01),LY294002预处理后p-Akt表达较LPS组明显降低,Bax表达显著上调,Bcl-2的表达下降,Caspase-3表达明显增加,且MSCs的凋亡率也增加(P<0.01)。结论 TLR4对MSCs的凋亡具有抑制作用,其作用机制可能与激活IP3K/Akt信号通路,继而抑制Caspase-3活性有关。

ObjectiveTo study the effect the toll-like receptor4(TLR4)on apoptosis of bone marrow mesenchymal stem cells and mechanisms.MethodsMSCs were cultured in vitro.Flow cytometry was used to identify MSCs.The experiment was divided into four groups:control group,LPS group,LPS+TLR4blockers group,LPS+LY294002group,treated with hypoxia for6h.The protein expression of TLR4,p-Akt,Akt,Bax,Bcl2,Caspase-3was detected by Western blot.Cell apoptosis rate was detected flow cytometry.ResultsCompared to the control group,cell apoptosis rate was significantly decreased in LPS group(P<0.01).LPS treatment increased the expression of p-Akt and Bcl-2in MSCs(P<0.01),decreased the expression of Bax and caspase-3(P<005).Compared to the LPS group,TLR4blockers and LY294002decreased the apoptosis rate of MSCs and the expression of p-Akt and Bcl-2,increased Bax and Caspase-3level(P<0.05).ConclusionTLR4inhibits apoptosis of MSCs,and its mechanism may be related to activation of PI3K/Akt signal pathway and then inhibition of Caspase-3activity.