背景:鸟分枝杆菌复合体(MAC),包括胞内分枝杆菌在内,胞内分枝杆菌是生长缓慢的分枝杆菌中的一员,在影响免疫功能低下和老年人群的人类中,导致相当大比例的非结核性分枝杆菌肺病。病原体在恶劣环境中的适应对于在宿主内建立感染和持久性至关重要。然而,细胞内分枝杆菌应激反应的复杂细胞和分子机制仍需充分探索。我们旨在阐明酸性和氧化应激条件下胞内分枝杆菌的转录反应。
结果:在转录组水平,在10mM过氧化氢的氧化应激下,80个基因显示[FC]≥2.0,p<0.05。具体来说,77个基因上调,而3个基因下调。在功能分析中,氧化应激条件激活DNA复制,核苷酸切除修复,失配修复,同源重组,和结核病途径。此外,我们的结果表明,DNA复制和修复系统的基因,比如dnaB,dinG,urvB,uvrD2和recA,是抵抗氧化应激不可或缺的。相反,在pH4.5的酸性胁迫下,显示了878个基因[FC]≥2.0,p<0.05。在这些基因中,339人上调,而539人被下调。功能分析强调氮和硫代谢途径是对酸性胁迫的主要反应。我们的发现提供了氮和硫代谢基因在响应酸性胁迫中起关键作用的证据。包括narghij,nirBD,naru,NarK3CysND,cysC,cysH,铁氧还蛋白1和2,以及甲酸脱氢酶。
结论:我们的结果表明,在宿主内恶劣的微环境下,对细胞内分枝杆菌存活可能至关重要的几种途径的激活。这项研究表明了应激反应在胞内分枝杆菌感染中的重要性,并确定了有希望的治疗靶标。
BACKGROUND: Mycobacterium avium complex (MAC), including Mycobacterium intracellulare is a member of slow-growing mycobacteria and contributes to a substantial proportion of nontuberculous mycobacterial lung disease in humans affecting immunocompromised and elderly populations. Adaptation of pathogens in hostile environments is crucial in establishing infection and persistence within the host. However, the sophisticated cellular and molecular mechanisms of stress response in M. intracellulare still need to be fully explored. We aimed to elucidate the transcriptional response of M. intracellulare under acidic and oxidative stress conditions.
RESULTS: At the transcriptome level, 80 genes were shown [FC] ≥ 2.0 and p < 0.05 under oxidative stress with 10 mM hydrogen peroxide. Specifically, 77 genes were upregulated, while 3 genes were downregulated. In functional analysis, oxidative stress conditions activate DNA replication, nucleotide excision repair, mismatch repair, homologous recombination, and tuberculosis pathways. Additionally, our results demonstrate that DNA replication and repair system genes, such as dnaB, dinG, urvB, uvrD2, and recA, are indispensable for resistance to oxidative stress. On the contrary, 878 genes were shown [FC] ≥ 2.0 and p < 0.05 under acidic stress with pH 4.5. Among these genes, 339 were upregulated, while 539 were downregulated. Functional analysis highlighted nitrogen and sulfur metabolism pathways as the primary responses to acidic stress. Our findings provide evidence of the critical role played by nitrogen and sulfur metabolism genes in the response to acidic stress, including narGHIJ, nirBD, narU, narK3, cysND, cysC, cysH, ferredoxin 1 and 2, and formate dehydrogenase.
CONCLUSIONS: Our results suggest the activation of several pathways potentially critical for the survival of M. intracellulare under a hostile microenvironment within the host. This study indicates the importance of stress responses in M. intracellulare infection and identifies promising therapeutic targets.