From development to aging and disease, the brain parenchyma is under the constant threat of debris accumulation, in the form of dead cells and protein aggregates. To prevent garbage buildup, the brain is equipped with efficient phagocytes: the microglia. Microglia are similar, but not identical to other tissue macrophages, and in this review, we will first summarize the differences in the origin, lineage and population maintenance of microglia and macrophages. Then, we will discuss several principles that govern macrophage phagocytosis of apoptotic cells (efferocytosis), including the existence of redundant recognition mechanisms (“find-me” and “eat-me”) that lead to a tight coupling between apoptosis and phagocytosis. We will then describe that resulting from engulfment and degradation of apoptotic cargo, phagocytes undergo an epigenetic, transcriptional and metabolic rewiring that leads to trained immunity, and discuss its relevance for microglia and brain function. In summary, we will show that neuroimmunologists can learn many lessons from the well-developed field of macrophage phagocytosis biology.

从发育到衰老和疾病，脑实质不断受到碎片积累的威胁，这些碎片以死亡细胞和蛋白质聚集体的形式积累。为了防止垃圾堆积，大脑配备了高效的吞噬细胞：小胶质细胞。小胶质细胞与其他组织巨噬细胞相似，但不完全相同，在这篇综述中，我们将首先总结小胶质细胞和巨噬细胞在起源、谱系和群体维持方面的差异。然后，我们将讨论控制凋亡细胞巨噬细胞吞噬作用（胞吞作用）的几个原理，包括导致细胞凋亡和吞噬作用之间紧密耦合的冗余识别机制（“找到我”和“吃我”）的存在。然后，我们将描述由于凋亡货物的吞噬和降解，吞噬细胞经历表观遗传、转录和代谢重新布线，从而产生训练有素的免疫力，并讨论其与小胶质细胞和大脑功能的相关性。总之，我们将证明神经免疫学家可以从发达的巨噬细胞吞噬生物学领域学到许多教训。