穿透支原体LAMPs诱导NF-kB激活介导小鼠巨噬细胞凋亡

Mycoplasma penetrans lipid-associated membrane proteins induce nuclear factor κB activation-mediated apoptosis in mouse macrophage

摘要:

研究穿透支原体(Mpe)脂质相关膜蛋白(LAMPs)能否诱导小鼠巨噬细胞凋亡, 并阐明其可能的分子机制, 以了解Mpe潜在的致病性。用Annexin-V-FITC凋亡检测试剂盒和DNA Ladder方法检测Mpe LAMPs诱导体外培养的小鼠巨噬细胞系Raw264.7细胞的凋亡。以间接免疫荧光和Western blotting方法检测经Mpe LAMPs处理的小鼠巨噬细胞NF-κB的激活和NF-κB抑制剂吡咯啉烷二甲基硫脲(PDTC)对细胞凋亡的影响。结果表明：Mpe LAMPs能诱导小鼠巨噬细胞发生早期或晚期凋亡; Mpe LAMPs能诱导激活小鼠巨噬细胞的NF-κB, 使其从细胞浆中转位到细胞核内; PDTC能显著地抑制经处理的小鼠巨噬细胞的NF-κB的激活, 且能抑制Mpe LAMPs诱导的巨噬细胞发生凋亡。因此, Mpe LAMPs诱导小鼠巨噬细胞凋亡可能与NF-κB的激活有关, 因而Mpe可能是一个重要的致病因素。

关键词:穿透支原体; 膜蛋白; 核因子kB; 凋亡

Abstract:

To investigate the potential pathogenicity of Mycoplasma penetrans (M. penetrans) and the possible molecular mechanisms, we investigated whether M. penetrans lipid-associated membrane proteins (LAMPs) could induce mouse macrophages Raw264.7 apoptosis by activating nuclear factor kB (NF-kB). Apoptosis was detected in M. penetrans LAMPs-stimulated mouse macrophages by Annexin-V-FITC staining and DNA fragmentation analysis. We also analyzed the activation of NF-kB and the effects of pyrrolidine dithiocarbamate (PDTC), an inhibitor of NF-kB, on M. penetrans LAMPs-induced mouse macrophages apoptosis by indirect immunofluorescence and Western blotting. Our results sug-gested that M. penetrans LAMPs could induce mouse macrophages significant early- and late-stage apoptosis. Agarose gel electrophoresis of the DNA of LAMPs-challenged cells revealed that a ladder-like pattern of migration of DNA indicative of apoptosis. M. penetrans LAMPs could activate NF-kB in mouse macrophages. PDTC could partially inhibit the activa-tion of NF-κB and thus inhibit M. penetrans LAMPs-induced mouse macrophages apoptosis. This study demonstrates that M. penetrans LAMPs may be an important etiological factor due to its ability to induce mouse macrophages apoptosis, which was probably mediated through the activation of NF-kB.

Key words:Mycoplasma penetrans; membrane proteins; nuclear factor kappa B; apoptosis