脂多糖提高巨噬细胞可溶性肿瘤坏死因子相关凋亡诱导配体的表达并诱导肝细胞凋亡

目的探讨脂多糖(LPS)、巨噬细胞表达肿瘤坏死因子相关凋亡诱导配体(TRAIL)和肝细胞凋亡的相互关系。方法LPS刺激巨噬细胞后,以流式细胞仪测定细胞表面的TRAIL表达,用酶联免疫吸附法(ELISA)法检测培养上清中可溶性TRAIL的表达;以(?)铬释放试验测定可溶性TRAIL和膜性TRAIL 对HepG2细胞的毒性作用,并用Annexin V染色法验证凋亡细胞的产生。结果经100 ng/ml LPS刺激后, 只有9.8%的巨噬细胞有TRAIL的表达,而培养上清中可溶性TRAIL达(67.4±5.1)ng/ml,有明显增加。巨噬细胞培养上清液中可溶性TRAIL能溶解HepG2细胞,经Annexin V染色法证实为细胞凋亡,此作用可被特异性TRAIL抗体阻断。结论LPS能增加巨噬细胞可溶性TRAIL表达,并诱导肝细胞凋亡,提示TRAIL在病毒性肝炎发病机制中有重要作用。

Lipopolysaccharide (LPS) increases tumor necrosis factor-alpha related apoptosis induced-ligand (TRAIL)in macrophages killing HepG2 cells

Objective To investigate the influence of lipopolysaccharide (LPS) on macrophages expressing TNF-alpha related apoptosis induced-ligand (TRAIL) and its relation to apoptosis of HepG2 cell line. Methods Membrane-bound TRAIL (mTRAIL) was measured by flow cytometry; soluble TRAIL in supernatant was detected by enzyme-linked immunoabsorbent sandwich assay (ELISA); cytotoxicity of TRAIL to HepG2 cell line was measured by chromium release assay, and apoptosis of HepG2 cell was confirmed by Annexin V staining. Results LPS only slightly increased membrane-bound TRAIL expression of macrophages. On the other hand, soluble TRAIL in the supernatant was increased with LPS stimulation, and the optimal concentration of LPS was 100ng/ml (sTRAIL value 67.40 ng/ml (?) 5.08 ng/ml). The soluble TRAIL in the supernatant was cytotoxic to HepG2 cells, and this activity can be blocked by TRAIL neutralizing antibodies. Conclusion LPS increases the expression of soluble TRAIL in macrophages, and soluble TRAIL is toxic to HepG2 cells. All of our results indicate that TRAIL may play an important role in the pathogenesis of viral hepatitis