Sharma Monica, Sharma Swati, Ray Pallab, Chakraborti Anuradha
Molecular Genetics Laboratory, Department of Experimental Medicine and Biotechnology, Postgraduate Institute of Medical Education & Research (PGIMER), Chandigarh - India.
Bacteriology Laboratory, Department of Medical Microbiology, Postgraduate Institute of Medical Education & Research (PGIMER), Chandigarh - India.
Drug Target Insights. 2020 Oct 7;14:26-33. doi: 10.33393/dti.2020.2103. eCollection 2020.
Genome plasticity of is responsible for the reduced efficacy of various antibiotics and capsular polysaccharide-based vaccines. Therefore, targets independent of capsular types are sought to control the pneumococcal pathogenicity. UDP-glucose pyrophosphorylase (UGPase) is one such desired candidate being responsible for the synthesis of UDP-glucose, a sugar precursor in capsular biosynthesis and metabolic Leloir pathway. Being crucial to pneumococcal pathobiology, the effect of UGPase inhibition on virulence was evaluated in vitro.
A putative inhibitor, uridine diphosphate (UDP), was evaluated for effective inhibitory concentration in and A549 cells, its efficacy and toxicity. The effect of UDP on adherence and phagocytosis was measured in human respiratory epithelial (A549 and HEp-2) and macrophage (THP1 and J774.A.1) cell lines respectively.
A differential effective inhibitory concentration of UDP for UGPase inhibition was observed in and A549 cells, that is, 5 and 100 µM respectively. UDP treatments lowered percent cytotoxicity in pneumococcal-infected monolayers and didn't exert adverse effects on viabilities. adherence to host cells decreased significantly with UDP treatments. UDP induced the secretion of interleukin (IL)-1β, tumor necrosis factor (TNF)-α, IL-6, and IL-8 and increased pneumococcal phagocytosis.
Our study shows UDP-mediated decrease in the virulence of and demonstrates UDP as an effective inhibitor of pneumococcal UGPase.
肺炎链球菌的基因组可塑性导致各种抗生素和基于荚膜多糖的疫苗效力降低。因此，人们寻找独立于荚膜类型的靶点来控制肺炎链球菌的致病性。尿苷二磷酸葡萄糖焦磷酸化酶（UGPase）就是这样一个理想的候选靶点，它负责合成尿苷二磷酸葡萄糖，这是荚膜生物合成和代谢Leloir途径中的一种糖前体。由于UGPase对肺炎链球菌致病生物学至关重要，因此在体外评估了UGPase抑制对其毒力的影响。
评估一种假定的抑制剂尿苷二磷酸（UDP）在肺炎链球菌和A549细胞中的有效抑制浓度、效力和毒性。分别在人呼吸道上皮（A549和HEp-2）和巨噬细胞（THP1和J774.A.1）细胞系中测量UDP对黏附和吞噬作用的影响。
观察到UDP对肺炎链球菌和A549细胞中UGPase抑制的有效抑制浓度存在差异，分别为5和100 μM。UDP处理降低了肺炎链球菌感染单层细胞的细胞毒性百分比，且对细胞活力没有不良影响。UDP处理后，肺炎链球菌对宿主细胞的黏附显著降低。UDP诱导白细胞介素（IL）-1β、肿瘤坏死因子（TNF）-α、IL-6和IL-8的分泌，并增加肺炎链球菌的吞噬作用。
我们的研究表明UDP介导肺炎链球菌毒力降低，并证明UDP是肺炎链球菌UGPase的有效抑制剂。
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