LC3-LpqH自噬靶向性抗结核DNA疫苗的制备

Preparation of an autophagy-targeted antituberculosis DNA vaccine encoding LpqH fused with LC3

目的制备结核杆菌脂蛋白抗原前体LpqH基因与微管相关蛋白轻链3(LC3)基因融合的抗结核DNA疫苗,探究其诱导与靶向自噬的效应。方法构建pCMV-LpqH与pCMV-LC3-LpqH重组质粒并转染RAW264.7细胞,免疫印迹法检测LC-3与LC3-LpqH的表达。转染pCMV-LpqH或pCMV-LC3-LpqH至GFP-LC3-RAW264.7细胞,免疫荧光法观察LC3-LpqH蛋白的定位。结果细胞转染pCMV-LpqH后LC-3表达水平增高。pCMV-LC3-LpqH在RAW264.7细胞的表达水平与质粒浓度呈剂量依赖性,并且LC3-LpqH与GFP-LC3体外表达后共定位于自噬体上。结论 pCMV-LC3-LpqH的表达能够增强自噬,并将LpqH抗原靶向定位于自噬体,为设计新型抗结核疫苗提供了新思路。

Objective To construct an autophagy-targeted vaccine harboring the genes encoding lipoprotein antigen precursor LpqH from Mycobacterium tuberculosis and microtubule-associated protein light chain-3 （ LC3 ）, and to investigate its efficacy of inducing and targeting autophagy. Methods The expressions of LC-3 and LC3-LpqH in RAW264.7 cells were detected by Western blotting after transfected with pCMV-LpqH and pCMV-LC3-LpqH plasmids respectively. The pCMV-LC3-LpqH or pCMV-LpqH plasmids were transfected into GFP-LC3-RAW264.7 cells to analyze the localization of LC3-LpqH by immunofluorescence staining. Results After transfected with pCMV-LpqH DNA, RAVV264.7 cells showed a significant increase of LC-3 amount. The LC3-LpqH fusion protein was also detected in RAW264.7 cells after pCMV-LC3-LpqH transfection and in a dose-dependent manner. Interestingly, LpqH was found to be transported to autophagosomes through the fusion protein, which was demonstrated by the co-localization of GFP-LC3 and LC3-LpqH on autophagosomes. Conclusion The recombinant plasmid encoding pCMV-LC3-LpqH could enhance the autophagy in vitro, and facilitate the localization of LpqH on autophagosomes. Our study provides a new practical strategy for the development of improved vaccines against Mycobacterium tuberculosis.