激活TLR2通过促进神经细胞死亡诱导假激酶表达诱导肺上皮细胞凋亡

Stimulating Toll-like receptor 2 promotes the cell apoptosis through augmenting the expression of NIPK in lung epithelial cells

目的探讨特异性激活Toll样受体2(TLR2)对于小鼠MLE-12肺上皮细胞发生细胞凋亡的影响及其潜在的分子机制。方法应用(0、1、3.3、10、33)ng/mL的TLR2特异性配基PAM3CYS4处理24 h或用33 ng/mL PAM3CYS4处理0、8、16、24、36、48 h,激活肺上皮细胞MLE-12的TLR2,使用Western blot法检测神经细胞死亡诱导假激酶(NIPK)和活性caspase-3的蛋白表达,用TUNEL凋亡检测试剂盒检测细胞凋亡的情况。结果与正常培养的MLE-12细胞相比,特异性激活TLR2可以促进NIPK和活性caspase-3的表达增加,细胞凋亡的阳性细胞数目增加;使用siRNA技术特异性抑制NIPK的表达后,显著抑制活性caspase-3表达,凋亡细胞数减少。结论特异性激活TLR2可增加NIPK的表达,促进肺上皮细胞发生凋亡。

Objective To investigate if stimulating Toll-like receptor 2 （TLR2） specifically induces the cell apoptosis in mouse lung epithelial cells （MLE-12） and related potential mechanism. Methods TLR2 was stimulated by 0, 1, 3.3, 10, 33 ng/mL PAM3CYS4 for 24 hours, or 33 ng/mL PAM3CYS4 for 0, 8, 16, 24, 36, 48 hours, respectively. The expressions of neuronal cell death inducible putative kinase （NIPK） and cleaved caspase-3 were detected by Western blotting; the number of apoptotic cells was counted by TUNEL staining in MLE-12 lung epithelial cells. Results Responding to TLR2-specific stimulation, the expressions of NIPK and cleaved caspase-3 were significantly elevated, and the number of apoptotic cells increased. Inhibiting NIPK by siRNA transfection decreased the expression of cleaved caspase-3 and the number of apoptotic cells. Conclusion Stimulating TLR2 signaling using TLR2-specific ligands PAM3CYS4 promotes the cell apoptosis through increasing the expression of NIPK.