结核分枝杆菌Rv2647蛋白对肺组织损伤效应的初步研究
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南京医科大学第二附属医院

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结核分枝杆菌分泌蛋白Rv2647通过泛素化调控抑制巨噬细胞焦亡的机制研究


Preliminary study on the effect of Mycobacterium tuberculosis Rv2647 protein on lung injury
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    摘要:

    目的 通过噬菌体重组技术分别构建结核分枝杆菌Rv2647基因的敲除株和回补株以及过表达Rv2647的耻垢分枝杆菌,评估结核分枝杆菌Rv2647蛋白对模型鼠肺组织的损伤效应。方法 构建同源交换位点并整合到结核分枝杆菌噬菌体基因组,获取噬菌粒并将其导入耻垢分枝杆菌(Mycobacterium smegmatis,Ms),构建具有同源交换位点的重组噬菌体。体外扩增获得高滴度重组噬菌体并转染结核分枝杆菌(H37Rv),37℃静置培养28天,挑取单克隆进行PCR验证,获得Rv2647基因敲除株(H37RvΔRv2647)。PCR 扩增Rv2647基因并通过无缝克隆分别将其整合到载体pMV361和pMV261多克隆位点处,获得阳性质粒后分别电转化H37RvΔRv2647和Ms,获得结核分枝杆菌回补株(H37RvΔRv2647::Rv2647)及过表达Rv2647的耻垢分枝杆菌(Ms::Rv2647)。分别以H37Rv、H37RvΔRv2647、H37RvΔRv2647::Rv2647、Ms及Ms::Rv2647的菌液经气管攻击C57BL/6小鼠,分别于30 天、7 天比较结核分枝杆菌与耻垢分枝杆菌模型鼠的存活率、肺组织细菌负荷及肺组织病理损伤程度。结果 (1)PCR结果显示,H37RvΔRv2647中Rv2647基因缺失,H37RvΔRv2647::Rv2647及Ms::Rv2647中Rv2647基因皆存在;(2)H37RvΔRv2647、H37Rv及H37RvΔRv2647::Rv2647组模型鼠30 天存活率分别为100.00%、83.33%及83.33%;Ms和Ms::Rv2647组模型鼠的7 天存活率分别为100.00%和83.33%;H37RvΔRv2647组模型鼠肺组织细菌负荷(Log10 CFU)为3.40±0.18,显著低于H37Rv组(3.86±0.15,P<0.001)和H37RvΔRv2647::Rv2647组(3.80±0.16,P<0.01);H37RvΔRv2647组模型鼠肺组织炎症面积(%)为4.37±3.06,显著低于H37Rv组(62.76±14.24,P<0.001)和H37RvΔRv2647::Rv2647组(67.37±0.45,P<0.001);Ms组模型鼠肺组织细菌负荷(Log10 CFU)为2.53±0.16,显著低于Ms::Rv2647组(2.81±0.13,P<0.01);Ms组模型鼠肺组织炎症面积(%)为5.71±1.29,显著低于Ms::Rv2647组(33.13±13.84,P<0.05)。结论 (1)成功构建了结核分枝杆菌Rv2647基因敲除株(H37RvΔRv2647)及回补株(H37RvΔRv2647::Rv2647)以及过表达Rv2647的耻垢分枝杆菌(Ms::Rv2647);(2)Rv2647蛋白可能通过抑制宿主对结核分枝杆菌的清除,加重了模型鼠肺组织病理损伤,其具体机制值得进一步探究。

    Abstract:

    Objective To constract the Rv2647-deleted strain and Rv2647-complemented strain of Mycobacterium tuberculosis (M. tb) and Rv2647-overexpressing Mycobacterium smegmatis (Ms::Rv2647) by phage recombination technique and to evaluate the effect of M. tb Rv2647 protein on lung injury in model mice. Methods The affinal exchange sites was constructed and integrated into the phage genomes of M. tb, then the phagemids were obtained and introduced into Mycobacterium smegmatis (Ms). Ultimately, the recombinant phages with the same AES were constructed. Obtaining high titer recombinant phages via amplification in vitro and transfecting them into M. tb, which was cultured for 28 days at 37℃. The single clone was selected and verified by PCR and the Rv2647-deleted strain (H37RvΔRv2647) was obtained. The Rv2647 gene was amplified by PCR and was integrated into the multiple clone sites of vector pMV361 and pMV261 through seamless cloning to obtain the positive plasmids, which were transfected into H37RvΔRv2647 and Ms to obtain the Rv2647-complemented strain (H37RvΔRv2647::Rv2647) and Rv2647-overexpressing Ms (Ms::Rv2647), respectively. The suspension of H37Rv, H37RvΔRv2647, H37RvΔRv2647::Rv2647, Ms, and Ms::Rv2647 were used to infect C57BL/6 mice via tracheal injection. After infection for 30 days and 7 days, the survival, lung bacterial load, and lung injury of model mice were evaluated. Results (1) The PCR showed that Rv2647 gene was missing in the H37RvΔRv2647, while it was present in the H37RvΔRv2647::Rv2647 and Ms::Rv2647; (2) The 30-day survival of model mice infected with H37RvΔRv2647, H37Rv, and H37RvΔRv2647::Rv2647 were 100.00%, 83.33%, and 83.33%, respectively; The 7-day survival of model mice infected with Ms and Ms::Rv2647 were 100.00% and 83.33%; The lung bacterial load (Log10 CFU) of model mice in H37RvΔRv2647 group was 3.40±0.18, which was significantly lower than those of H37Rv group (3.86±0.15, P<0.001) and H37RvΔRv2647::Rv2647 group (3.80±0.16, P<0.01); The inflammation area (%) in lung tissues of model mice in the H37RvΔRv2647 group was 4.37±3.06, which was significantly lower than those in the H37Rv group (62.76±14.24, P<0.001) and H37RvΔRv2647::Rv2647 group (67.37±0.45, P<0.001). The lung bacterial load (Log10 CFU) of model mice in Ms group was 2.53±0.16, which was significantly lower than that of Ms::Rv2647 group (2.81±0.13, P<0.01); The inflammation area (%) in lung tissue of model mice in the Ms group was 5.71±1.29, which was significantly lower than that in the Ms::Rv2647 group (33.13±13.84, P<0.05). Conclusion The Rv2647-deleted strain (H37RvΔRv2647) and Rv2647-complementary strain (H37RvΔRv2647::Rv2647) of M. tb and Rv2647-overexpressing Ms (Ms::Rv2647) were successfully constructed. Rv2647 protein may aggravate lung injury via inhibiting host clearance of M. tb, of which mechanism is worthy of further investigation.

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  • 收稿日期:2024-06-25
  • 最后修改日期:2024-09-10
  • 录用日期:2024-11-05
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