长链非编码RNA肺腺癌转移相关转录本1在结核感染中的表达及意义

Expression and clinical significances of lncRNA MALAT 1 in Mycobacterium tuberculosis infection

目的：探讨长链非编码RNA（lncRNA）肺腺癌转移相关转录本1（MALAT1）在结核感染中的表达及其临床意义。方法采用实时荧光定量PCR（ RT-PCR）技术检测75例肺结核病患者（结核组）及32例健康体检者（健康对照组）外周血单个核细胞（ PBMC）中MALAT1的表达量,分析其与结核病发生发展以及转归的相关性。采用RT-PCR技术检测感染结核分枝杆菌（ Mycobacterium tuberculosis,Mtb）的人巨噬细胞（THP-1）中MALAT1的差异表达；用小干扰RNA诱导THP-1细胞中MALAT1沉默,检测Mtb感染后炎症因子TNF-α、IL-6的表达及THP-1细胞对Mtb杀菌功能的变化。结果 RT-PCR检测结果显示 MALAT1在肺结核患者 PBMC 中的相对表达水平是健康对照组的（4.05＆#177;0.86）倍,差异有统计学意义（P〈0.01）。 MALAT1在初治和复治肺结核病例中表达差异无统计学意义（P〉0.05）；MALAT1随结核病患者肺部空洞累及范围的增加而升高。肺结核患者PBMC中MALAT1表达量随着治疗时间逐渐下降,恢复至正常水平。 THP-1细胞感染Mtb后MALAT1表达显著上调（P〈0.01）；沉默MALAT1的THP-1细胞感染Mtb后TNF-α和IL-6水平显著升高（P〈0.01）。以Mtb感染后0 h时间点的细胞内荷菌量为基准,Mtb感染后72 h时沉默MALAT1的THP-1细胞内Mtb的存活率显著低于对照感染组（P〈0.01）。结论 MALAT1在结核感染过程中表达升高,且与结核的发展和转归有关。下调MALAT1表达可增强巨噬细胞对胞内Mtb的清除能力。

Objective To investigate the expression and the clinical significances of a long non-coding RNA （lncRNA） metastasis-associated lung adenocarcinoma transcript 1 （MALAT1） in Mycobacteri-um tuberculosis （ Mtb） infection. Methods The expression of MALAT1 in peripheral blood mononuclear cells （ PBMC） collected from 75 hospitalized patients with pulmonary tuberculosis （ TB） and 32 healthy sub-jects were analyzed by real-time quantitative PCR （ RT-PCR） . Total RNAs were extracted from THP-1 mac-rophages infected with Mtb strains and the levels of MALAT1 were detected by RT-PCR. THP-1 macropha-ges were transfected with siRNAs to knock down the expression of MALAT1 and then were infected with Mtb strains. The levels of TNF-αand IL-6 were measured by ELISA. The entry and intracellular survival of Mtb strains in THP-1 macrophages were analyzed by bacterial culture at indicated time points. Results The rel-ative expression level of MALAT1 in TB patients was （4. 05＆#177;0. 86） times that of MALAT1 in healthy con-trols （P〈0. 01）. No significant differences in the expression of MALAT1 were observed between new and re-lapsed cases （P〉0. 05）. The expression of MALAT1 increased with the occurrence and extension of lung cavitation in patients with pulmonary tuberculosis （P〈0. 05）. The levels of MALAT1 in patients with pulmo-nary tuberculosis were gradually down-regulated to the normal level after receiving pharmacotherapy. Results of the RT-PCR analysis indicated that the expression of MALAT1 in Mtb infected-THP-1 macrophages in-creased significantly （P〈0. 01）. Higher levels of TNF-α and IL-6 were observed in Mtb infected-THP-1 macrophages with silenced expression of MALAT1 （P〈0. 01）. Compared with the THP-1 macrophages transfected with control fragment, the survival rate of intracellular Mtb strains in THP-1 macrophages trans-fected with siMALAT1 was significantly decreased at the time point of 72 h. Conclusion Higher levels of MALAT1 were detected in patients with TB, which was associated with the development and outcome of TB. The intracellular killing of Mtb strains by THP-1 macrophages could be enhanced by down-regulating the ex-pression of MALAT1.