Institute of Neuropathology, Faculty of Medicine, University of Freiburg, Freiburg, Germany.
Berta-Ottenstein-Programme, Faculty of Medicine, University of Freiburg, Freiburg, Germany.
Glia. 2020 Aug;68(8):1655-1672. doi: 10.1002/glia.23822. Epub 2020 Mar 17.
Among the myeloid cells in the central nervous system (CNS) microglia are the main representatives of the innate immune system. Microglial fulfil tasks beyond phagocytosing debris and host defense against invading microorganism. During brain development microglia guide for example neurons for proper CNS formation, in adulthood they maintain tissue homeostasis and in aging microglia may become pro-inflammatory and finally exhausted. Recently, several endogenous and exogenous factors were identified that essentially shape the microglial phenotype during both steady-state and pathological conditions. On the one hand, microglia receive inputs from CNS-endogenous sources for example, via crosstalk with other glial cells and neurons but on the other hand microglia are also highly modulated by external signals. Among them, host microbiota-the host's resident bacteria-are vital regulators of the CNS innate immune system. This review summarizes key extrinsic and intrinsic factors, with special focus on the host microbiota, that essentially influence microglia functions and states during development, homeostasis, and disease.
在中枢神经系统 (CNS) 中的髓样细胞中，小胶质细胞是先天免疫系统的主要代表。小胶质细胞的功能不仅限于吞噬碎片和抵御入侵微生物的宿主防御。在大脑发育过程中，小胶质细胞可以引导神经元形成适当的 CNS，在成年期它们维持组织内稳态，在衰老过程中小胶质细胞可能会变得炎症前状态并最终耗尽。最近，已经确定了几种内源性和外源性因素，这些因素在稳态和病理条件下对小胶质细胞表型的形成具有重要影响。一方面，小胶质细胞从 CNS 内源性来源接收输入，例如通过与其他神经胶质细胞和神经元的相互作用，但另一方面，小胶质细胞也受到外部信号的高度调节。其中，宿主微生物群——宿主的常驻细菌——是中枢神经系统先天免疫系统的重要调节剂。这篇综述总结了关键的外在和内在因素，特别关注宿主微生物群，这些因素对小胶质细胞在发育、内稳态和疾病过程中的功能和状态具有重要影响。
