Cholesterol oxidase is indispensable in the pathogenesis of Mycobacterium tuberculosis.
Cholesterol oxidase is indispensable in the pathogenesis of Mycobacterium tuberculosis.
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DOI：
10.1371/journal.pone.0073333
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发表时间：
2013
期刊：
影响因子：
3.7
通讯作者：
Dziadek J
中科院分区：
文献类型：
--
作者：
Klink M;Brzezinska M;Szulc I;Brzostek A;Kielbik M;Sulowska Z;Dziadek J
尽管进行了大量研究，但结核分枝杆菌(Mtb)毒力的分子机制仍不清楚。胆固醇氧化酶(Chod)是一种胞外酶，能够将胆固醇转化为3-酮-4-烯衍生物胆固酮，已被认为在结核分枝杆菌的毒力中发挥了作用。在这里，我们验证了Chod能够改变人巨噬细胞的杀菌和促炎活性的假设。我们还试图确定补体受体3(CR3)和Toll样受体2(TLR2)介导的信号通路在巨噬细胞对结核分枝杆菌反应发展中的作用。我们发现，缺乏功能性Chod基因的结核杆菌突变体(ΔChod)在巨噬细胞中的细胞内复制效率低于野生型突变株。用单抗阻断CR3和TLR2可增强ΔChod在巨噬细胞内的存活率。我们还发现，与野生型结核分枝杆菌不同，ΔChod株诱导巨噬细胞产生一氧化氮，这一作用依赖于TLR2，而不是CR3，信号通路。野生型和突变型菌株都能抑制活性氧(ROS)的产生，但ΔChod菌株的抑制程度要小得多。阻断TLR2介导的信号转导可阻断野生型Mtb对巨噬细胞产生ROS的抑制作用。野生型Mtb，而不是ΔChod株，降低了佛波酯诱导的细胞外信号调节激酶1和2(ERK1/2)的磷酸化，这两个信号通路都参与了TLR2和CR3介导的信号通路。我们的发现还显示，在ΔChod感染的巨噬细胞中，巨噬细胞产生的IL-10显著低于野生型结核分枝杆菌感染的巨噬细胞。然而，巨噬细胞在感染突变株或野生型菌株后产生的肿瘤坏死因子-α是相同的。综上所述，我们在这里证明了Chod是Mtb干扰TLR2介导的信号通路以及随后病原体在人巨噬细胞中的细胞内生长和存活所必需的。
Despite considerable research effort, the molecular mechanisms of Mycobacterium tuberculosis (Mtb) virulence remain unclear. Cholesterol oxidase (ChoD), an extracellular enzyme capable of converting cholesterol to its 3-keto-4-ene derivative, cholestenone, has been proposed to play a role in the virulence of Mtb. Here, we verified the hypothesis that ChoD is capable of modifying the bactericidal and pro-inflammatory activity of human macrophages. We also sought to determine the contribution of complement receptor 3 (CR3)- and Toll-like receptor 2 (TLR2)-mediated signaling pathways in the development of macrophage responses to Mtb. We found that intracellular replication of an Mtb mutant lacking a functional choD gene (ΔchoD) was less efficient in macrophages than that of the wild-type strain. Blocking CR3 and TLR2 with monoclonal antibodies enhanced survival of ΔchoD inside macrophages. We also showed that, in contrast to wild-type Mtb, the ΔchoD strain induced nitric oxide production in macrophages, an action that depended on the TLR2, but not the CR3, signaling pathway. Both wild-type and mutant strains inhibited the production of reactive oxygen species (ROS), but the ΔchoD strain did so to a significantly lesser extent. Blocking TLR2-mediated signaling abolished the inhibitory effect of wild-type Mtb on ROS production by macrophages. Wild-type Mtb, but not the ΔchoD strain, decreased phorbol myristate acetate-induced phosphorylation of extracellular signal-regulated kinases 1 and 2 (ERK1/2), which are involved in both TLR2- and CR3-mediated signaling pathways. Our finding also revealed that the production of interleukin 10 by macrophages was significantly lower in ΔchoD-infected macrophages than in wild-type Mtb-infected macrophages. However, tumor necrosis factor-α production by macrophages was the same after infection with mutant or wild-type strains. In summary, we demonstrate here that ChoD is required for Mtb interference with the TLR2-mediated signaling pathway and subsequent intracellular growth and survival of the pathogen in human macrophages.
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影响因子：
3.9
作者：
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影响因子：
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