Soni Vijay, Upadhayay Sandeep, Suryadevara Priyanka, Samla Ganesh, Singh Archana, Yogeeswari Perumal, Sriram Dharmarajan, Nandicoori Vinay Kumar
National Institute of Immunology, New Delhi, India; Department of Pharmacy, Birla Institute of Technology and Science-Pilani, Hyderabad Campus, Hyderabad, India.
National Institute of Immunology, New Delhi, India.
PLoS Pathog. 2015 Oct 21;11(10):e1005235. doi: 10.1371/journal.ppat.1005235. eCollection 2015 Oct.
M. tuberculosis N-acetyl-glucosamine-1-phosphate uridyltransferase (GlmUMtb) is a bi-functional enzyme engaged in the synthesis of two metabolic intermediates N-acetylglucosamine-1-phosphate (GlcNAc-1-P) and UDP-GlcNAc, catalyzed by the C- and N-terminal domains respectively. UDP-GlcNAc is a key metabolite essential for the synthesis of peptidoglycan, disaccharide linker, arabinogalactan and mycothiols. While glmUMtb was predicted to be an essential gene, till date the role of GlmUMtb in modulating the in vitro growth of Mtb or its role in survival of pathogen ex vivo / in vivo have not been deciphered. Here we present the results of a comprehensive study dissecting the role of GlmUMtb in arbitrating the survival of the pathogen both in vitro and in vivo. We find that absence of GlmUMtb leads to extensive perturbation of bacterial morphology and substantial reduction in cell wall thickness under normoxic as well as hypoxic conditions. Complementation studies show that the acetyl- and uridyl- transferase activities of GlmUMtb are independently essential for bacterial survival in vitro, and GlmUMtb is also found to be essential for mycobacterial survival in THP-1 cells as well as in guinea pigs. Depletion of GlmUMtb from infected murine lungs, four weeks post infection, led to significant reduction in the bacillary load. The administration of Oxa33, a novel oxazolidine derivative that specifically inhibits GlmUMtb, to infected mice resulted in significant decrease in the bacillary load. Thus our study establishes GlmUMtb as a strong candidate for intervention measures against established tuberculosis infections.
结核分枝杆菌N - 乙酰葡糖胺 - 1 - 磷酸尿苷转移酶（GlmUMtb）是一种双功能酶，分别由C端和N端结构域催化参与两种代谢中间体N - 乙酰葡糖胺 - 1 - 磷酸（GlcNAc - 1 - P）和UDP - GlcNAc的合成。UDP - GlcNAc是合成肽聚糖、二糖连接体、阿拉伯半乳聚糖和分枝硫醇所必需的关键代谢物。虽然glmUMtb被预测为必需基因，但迄今为止，GlmUMtb在调节结核分枝杆菌体外生长中的作用或其在病原体离体/体内存活中的作用尚未阐明。在此，我们展示了一项全面研究的结果，剖析了GlmUMtb在体外和体内介导病原体存活中的作用。我们发现，在常氧和低氧条件下，GlmUMtb的缺失会导致细菌形态的广泛扰动以及细胞壁厚度的显著降低。互补研究表明，GlmUMtb的乙酰转移酶和尿苷转移酶活性对于细菌在体外的存活是独立必需的，并且还发现GlmUMtb对于结核分枝杆菌在THP - 1细胞以及豚鼠体内的存活也是必需的。感染后四周，从感染的小鼠肺中耗尽GlmUMtb导致细菌载量显著降低。给感染小鼠施用一种特异性抑制GlmUMtb的新型恶唑烷衍生物Oxa33，导致细菌载量显著下降。因此，我们的研究确立了GlmUMtb作为针对已建立的结核病感染的干预措施的有力候选者。
