Kumar Ranjeet, Singh Pooja, Kolloli Afsal, Shi Lanbo, Bushkin Yuri, Tyagi Sanjay, Subbian Selvakumar
Public Health Research Institute, New Jersey Medical School, Rutgers, The State University of New Jersey, Newark, NJ, United States.
Front Mol Biosci. 2019 Oct 14;6:105. doi: 10.3389/fmolb.2019.00105. eCollection 2019.
Tuberculosis (TB), caused by (Mtb) remains as a leading killer among infectious diseases worldwide. The nature of the host immune response dictates whether the initial Mtb infection is cleared or progresses toward active disease, and is ultimately determined by intricate host-pathogen interactions that are yet to be fully understood. The early immune response to infection is mediated by innate immune cells, including macrophages and neutrophils that can phagocytose Mtb and mount an antimicrobial response. However, Mtb can exploit these innate immune cells for its survival and dissemination. Recently, it has become clear that the immune response and metabolic remodeling are interconnected, which is highlighted by the rapid evolution of the interdisciplinary field of immunometabolism. It has been proposed that the net outcome to Mtb infection-clearance or chronic disease-is likely a result of combined immunologic and metabolic activities of the immune cells. Indeed, host cells activated by Mtb infection have strikingly different metabolic requirements than naïve/non-infected cells. Macrophages activated by Mtb-derived molecules or upon phagocytosis acquire a phenotype similar to M1 with elevated production of pro-inflammatory molecules and rely on glycolysis and pentose phosphate pathway to meet their bioenergetic and metabolic requirements. In these macrophages, oxidative phosphorylation and fatty acid oxidation are dampened. However, the non-infected/naive, M2-type macrophages are anti-inflammatory and derive their energy from oxidative phosphorylation and fatty acid oxidation. Similar metabolic adaptations also occur in other phagocytes, including dendritic cells, neutrophils upon Mtb infection. This metabolic reprogramming of innate immune cells during Mtb infection can differentially regulate their effector functions, such as the production of cytokines and chemokines, and antimicrobial response, all of which can ultimately determine the outcome of Mtb-host interactions within the granulomas. In this review, we describe key immune cells bolstering host innate response and discuss the metabolic reprogramming in these phagocytes during Mtb infection. We focused on the major phagocytes, including macrophages, dendritic cells and neutrophils and the key regulators involved in metabolic reprogramming, such as hypoxia-inducible factor-1, mammalian target of rapamycin, the cellular myelocytomatosis, peroxisome proliferator-activator receptors, sirtuins, arginases, inducible nitric acid synthase and sphingolipids.
由结核分枝杆菌(Mtb)引起的结核病(TB)仍然是全球传染病中的主要杀手。宿主免疫反应的性质决定了最初的Mtb感染是被清除还是发展为活动性疾病,而这最终由尚未完全了解的复杂宿主-病原体相互作用决定。对感染的早期免疫反应由先天性免疫细胞介导,包括巨噬细胞和中性粒细胞,它们可以吞噬Mtb并引发抗菌反应。然而,Mtb可以利用这些先天性免疫细胞来实现其生存和传播。最近,免疫反应和代谢重塑之间的相互联系变得清晰,免疫代谢这一跨学科领域的迅速发展突出了这一点。有人提出,Mtb感染清除或慢性疾病的最终结果可能是免疫细胞免疫和代谢活动共同作用的结果。事实上,被Mtb感染激活的宿主细胞与未感染/未接触过病原体的细胞相比,具有截然不同的代谢需求。被Mtb衍生分子激活或吞噬后,巨噬细胞获得类似于M1的表型,促炎分子产生增加,并依赖糖酵解和磷酸戊糖途径来满足其生物能量和代谢需求。在这些巨噬细胞中,氧化磷酸化和脂肪酸氧化受到抑制。然而,未感染/未接触过病原体的M2型巨噬细胞具有抗炎作用,其能量来自氧化磷酸化和脂肪酸氧化。在其他吞噬细胞中,包括树突状细胞、感染Mtb后的中性粒细胞,也会发生类似的代谢适应。Mtb感染期间先天性免疫细胞的这种代谢重编程可以不同程度地调节它们的效应功能,如细胞因子和趋化因子的产生以及抗菌反应,所有这些最终都可以决定肉芽肿内Mtb与宿主相互作用的结果。在这篇综述中,我们描述了增强宿主先天性反应的关键免疫细胞,并讨论了Mtb感染期间这些吞噬细胞中的代谢重编程。我们重点关注了主要的吞噬细胞,包括巨噬细胞、树突状细胞和中性粒细胞,以及参与代谢重编程的关键调节因子,如缺氧诱导因子-1、雷帕霉素靶蛋白、细胞髓细胞瘤、过氧化物酶体增殖物激活受体、沉默调节蛋白、精氨酸酶、诱导型一氧化氮合酶和鞘脂。