National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi 110067, India.
National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi 110067, India; Department of Biochemistry, School of Chemical and Life Sciences, Jamia Hamdard, New Delhi 110062, India.
Int J Med Microbiol. 2020 Apr;310(3):151402. doi: 10.1016/j.ijmm.2020.151402. Epub 2020 Jan 23.
The ability to tolerate multiple host derived stresses, resist eradication and persist within the infected individuals is central to the pathogenicity of Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis (TB). Mycobacterial survival is contingent upon sensing environmental perturbations and initiating a fitting response to counter them. Therefore, understanding of molecular mechanisms underlying stress tolerance and sensing in Mtb is critical for devising strategies for TB control. Our study aims to delineate the role of ClpB, a heat shock protein of Hsp100 family, in the general stress response and persistence mechanisms of Mtb. We demonstrate that Mtb requires ClpB to survive under stressful conditions. Additionally, we show that ClpB is necessary for the bacteria to persist in latency-like conditions such as prolonged hypoxia and nutrient-starvation. The disruption of ClpB results in aberrant cellular morphology, impaired biofilm formation and reduced infectivity of Mtb ex vivo. Our study also reports an alternative role of ClpB as a chaperokine which elicits inflammatory response in host. We conclude that ClpB is essential for Mtb to survive within macrophages, and plays a crucial part in the maintenance of dormant Mtb bacilli in latent state. The absence of ClpB in human genome makes it an attractive choice as drug target for TB.
能够耐受多种宿主来源的应激、抵抗清除并在感染个体中持续存在是结核分枝杆菌(Mtb)致病性的核心,Mtb 是结核病(TB)的病原体。分枝杆菌的生存依赖于感知环境变化并启动适当的反应来对抗它们。因此,了解 Mtb 中应激耐受和感应的分子机制对于制定结核病控制策略至关重要。我们的研究旨在描绘 Hsp100 家族热休克蛋白 ClpB 在 Mtb 一般应激反应和持续存在机制中的作用。我们证明 Mtb 需要 ClpB 才能在应激条件下存活。此外,我们还表明 ClpB 对于细菌在潜伏样条件下(如长时间缺氧和营养饥饿)的持续存在是必需的。ClpB 的破坏导致细胞形态异常、生物膜形成受损和 Mtb 体外感染性降低。我们的研究还报告了 ClpB 作为一种伴侣蛋白的替代作用,它在宿主中引发炎症反应。我们得出结论,ClpB 对于 Mtb 在巨噬细胞内存活是必需的,并且在维持潜伏状态下休眠的 Mtb 杆菌中起着至关重要的作用。人类基因组中缺乏 ClpB 使其成为结核病药物靶点的一个有吸引力的选择。