猪肺炎支原体 NADH 氧化酶作为一种潜在的毒力介体发挥作用。

NADH oxidase of Mycoplasma hyopneumoniae functions as a potential mediator of virulence.

机构信息

Jiangsu Key Laboratory for Food Quality and Safety-State Key Laboratory Cultivation Base, Ministry of Science and Technology, Key Laboratory for Veterinary Bio-Product Engineering, Ministry of Agriculture and Rural Affairs, Institute of Veterinary Medicine, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, P.R. China.

Discipline of Microbiology, School of Life Sciences, College of Agriculture, Engineering and Science, University of KwaZulu-Natal (Westville campus), Private Bag X 54001, Durban, 4000, South Africa.

出版信息

BMC Vet Res. 2022 Apr 2;18(1):126. doi: 10.1186/s12917-022-03230-7.

DOI:10.1186/s12917-022-03230-7

PMID:35366872

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC8976378/

Abstract

BACKGROUND

Mycoplasma hyopneumoniae (M. hyopneumoniae) is the etiological agent of enzootic pneumonia, a highly infectious swine respiratory disease that distributed worldwide. The pathogenesis and virulence factors of M. hyopneumoniae are not fully clarified. As an important virulence factor of bacteria, nicotinamide adenine dinucleotide (NADH) oxidase (NOX) participates in host-pathogen interaction, however, the function of NOX involved in the pathogenesis of M. hyopneumoniae is not clear.

RESULTS

In this study, significant differences in NOX transcription expression levels among different strains of M. hyopneumoniae differed in virulence were identified, suggesting that NOX may be correlated with M. hyopneumoniae virulence. The nox gene of M. hyopneumoniae was cloned and expressed in Escherichia coli, and polyclonal antibodies against recombinant NOX (rNOX) were prepared. We confirmed the enzymatic activity of rNOX based on its capacity to oxidize NADH to NAD. Flow cytometry analysis demonstrated the surface localization of NOX, and subcellular localization analysis further demonstrated that NOX exists in both the cytoplasm and cell membrane. rNOX was depicted to mediate adhesion to immortalized porcine bronchial epithelial cells (hTERT-PBECs). Pre-neutralizing M. hyopneumoniae with anti-rNOX antibody resulted in a more than 55% reduction in the adhesion rate of high- and low-virulence M. hyopneumoniae strains to hTERT-PBECs. Moreover, a significant difference appeared in the decline in CCU titer between virulent (168) and virulence-attenuated (168L) strains. NOX not only recognized and interacted with host fibronectin but also induced cellular oxidative stress and apoptosis in hTERT-PBECs. The release of lactate dehydrogenase by NOX in hTERT-PBECs was positively correlated with the virulence of M. hyopneumoniae strains.

CONCLUSIONS

NOX is considered to be a potential virulence factor of M. hyopneumoniae and may play a significant role in mediating its pathogenesis.

摘要

背景

猪肺炎支原体（M. hyopneumoniae）是地方性肺炎的病原体，这是一种高度传染性的猪呼吸道疾病，分布于世界各地。M. hyopneumoniae 的发病机制和毒力因子尚未完全阐明。作为细菌的一个重要毒力因子，烟酰胺腺嘌呤二核苷酸（NADH）氧化酶（NOX）参与了宿主-病原体的相互作用，然而，NOX 参与 M. hyopneumoniae 发病机制的功能尚不清楚。

结果

本研究发现，不同毒力的 M. hyopneumoniae 菌株之间的 NOX 转录表达水平存在显著差异，提示 NOX 可能与 M. hyopneumoniae 的毒力有关。克隆并在大肠杆菌中表达了 M. hyopneumoniae 的 nox 基因，制备了针对重组 NOX（rNOX）的多克隆抗体。我们基于其将 NADH 氧化为 NAD 的能力来证实 rNOX 的酶活性。流式细胞术分析表明 NOX 定位于表面，亚细胞定位分析进一步表明 NOX 存在于细胞质和细胞膜中。rNOX 介导了对永生化猪支气管上皮细胞（hTERT-PBECs）的粘附。用抗-rNOX 抗体预先中和 M. hyopneumoniae 后，高毒力和低毒力 M. hyopneumoniae 菌株对 hTERT-PBECs 的粘附率降低了 55%以上。此外，毒力株（168）和毒力减弱株（168L）之间的 CCU 滴度下降也出现显著差异。NOX 不仅识别和与宿主纤连蛋白相互作用，还诱导 hTERT-PBECs 发生细胞氧化应激和凋亡。NOX 在 hTERT-PBECs 中释放的乳酸脱氢酶与 M. hyopneumoniae 菌株的毒力呈正相关。