Characterization and transcriptome analysis of Mycobacterium tuberculosis persisters.
Characterization and transcriptome analysis of Mycobacterium tuberculosis persisters.
复制标题
作者：
Keren I;Minami S;Rubin E;Lewis K
结核病在世界许多地区仍然是一个主要的公共卫生问题。控制这一流行病的重大障碍是治疗时间长以及大量潜伏感染人群的存在。细菌会形成休眠的、耐药的持留菌细胞，这可能是治疗急性和潜伏感染困难的原因。我们发现，在结核分枝杆菌中，在延滞期和指数生长早期阶段存在少量耐药持留菌，在指数生长后期和稳定期急剧增加，占菌群的约1%。这表明持留菌的形成受随机和确定性机制的共同调控。为了分离持留菌，用D - 环丝氨酸处理处于指数生长期的菌群，通过离心收集存活下来未被裂解的细胞。通过与Affymetrix芯片杂交获得了持留菌的转录组。转录组显示代谢和生物合成途径下调，这与一定程度的休眠状态相符。一组基因在持留菌中上调，这些基因可能参与持留菌的形成和维持。将持留菌转录组与几种体外休眠模型获得的转录组进行比较，确定了在所有情况下都上调的少数基因，这些基因可能代表一种核心的休眠反应。
据估计，地球上每三个人中就有一人感染结核分枝杆菌。控制结核分枝杆菌的两个主要问题是治疗时间长和大量潜伏感染人群。休眠的持留菌细胞可能是这两个问题的原因。我们发现结核分枝杆菌在体外以生长阶段依赖的方式产生持留菌。从指数生长期的菌群中分离出持留菌，它们的转录组显示出一种独特的休眠模式。这些结果首次深入了解了结核分枝杆菌持留菌，并指出了其形成的可能机制。
Tuberculosis continues to be a major public health problem in many parts of the world. Significant obstacles in controlling the epidemic are the length of treatment and the large reservoir of latently infected people. Bacteria form dormant, drug-tolerant persister cells, which may be responsible for the difficulty in treating both acute and latent infections. We find that in Mycobacterium tuberculosis, low numbers of drug-tolerant persisters are present in lag and early exponential phases, increasing sharply at late exponential and stationary phases to make up ~1% of the population. This suggests that persister formation is governed by both stochastic and deterministic mechanisms. In order to isolate persisters, an exponentially growing population was treated with d-cycloserine, and cells surviving lysis were collected by centrifugation. A transcriptome of persisters was obtained by using hybridization to an Affymetrix array. The transcriptome shows downregulation of metabolic and biosynthetic pathways, consistent with a certain degree of dormancy. A set of genes was upregulated in persisters, and these are likely involved in persister formation and maintenance. A comparison of the persister transcriptome with transcriptomes obtained for several in vitro dormancy models identified a small number of genes upregulated in all cases, which may represent a core dormancy response. It is estimated that every third person on the planet is infected with Mycobacterium tuberculosis. The two major problems in controlling M. tuberculosis are the length of the treatment and the large reservoir of latently infected people. Dormant persister cells may be responsible for both problems. We find that M. tuberculosis produces persisters in vitro in a growth phase-dependent manner. Persisters were isolated from an exponentially growing population, and their transcriptome shows a distinct pattern of dormancy. These results give the first insight into M. tuberculosis persisters and point to possible mechanisms responsible for their formation.