Institute of Neuropathology, University of Göttingen Göttingen, Germany.
Front Cell Neurosci. 2014 Apr 1;8:101. doi: 10.3389/fncel.2014.00101. eCollection 2014.
Microglia are the principal resident innate immune cells of the CNS. Their contributions to the normal development of the CNS, the maintenance and plasticity of neuronal networks and the safeguarding of proper functionality are becoming more and more evident. Microglia also survey the tissue homeostasis to respond rapidly to exogenous and endogenous threats, primarily with a protective outcome. However, excessive acute activation, chronic activity or an improper adaptation of their functional performance can foster neuropathologies. A key to the versatile response behavior of these cells is their ability to commit to reactive phenotypes, which reveal enormous complexity. Yet the respective profiles of induced genes and installed functions may build up on heterogeneous contributions of cellular subsets. Here, we discuss findings and concepts that consider the variety of microglial activities and response options as being based-at least in part-on a diversity of the engaged cells. Whether it is the production of proinflammatory cytokines, clearance of tissue debris, antigen presentation or the ability to sense neurotransmitters, microglial cells present with an unanticipated heterogeneity of their constitutive and inducible features. While the organizational principles of this heterogeneity are still largely unknown, functional implications are already perceptible.
小胶质细胞是中枢神经系统（CNS）中主要的常驻固有免疫细胞。它们对 CNS 的正常发育、神经元网络的维持和可塑性以及适当功能的保护作用变得越来越明显。小胶质细胞还监测组织的动态平衡，以快速响应外源性和内源性威胁，主要表现为保护作用。然而，过度的急性激活、慢性活动或其功能表现的不当适应会促进神经病理学的发生。这些细胞具有多功能反应行为的关键是它们能够向反应性表型转变的能力，这揭示了巨大的复杂性。然而，诱导基因和所安装功能的相应特征可能基于细胞亚群的异质性贡献。在这里，我们讨论了一些发现和概念，这些发现和概念认为小胶质细胞的各种活动和反应选择至少部分基于所涉及细胞的多样性。无论是产生促炎细胞因子、清除组织碎片、抗原呈递还是感知神经递质的能力，小胶质细胞都表现出其组成和诱导特征的出人意料的异质性。虽然这种异质性的组织原则在很大程度上仍然未知，但功能意义已经显而易见。
