导读
小胶质细胞被认为是中枢神经系统(CNS)的巨噬细胞，建立了针对病原体和毒素的固有免疫反应。然而，最近的研究表明，小胶质细胞的基因和蛋白表达具有昼夜节律模式;一些免疫激活标志物和生物钟基因在不需要免疫刺激的情况下呈节律性表达。此外，小胶质细胞对一天中不同时间的免疫挑战有不同程度的反应。这篇综述探讨了小胶质细胞功能的昼夜节律控制及其可能的生理意义。例如，我们讨论了突触修剪在一天的某一时刻在皮质中进行。我们还考虑了日常小胶质细胞功能对维持一般活动、体温和摄食等生物节律的影响。本文认为，发育阶段、脑区和病理状态不是评估小胶质细胞功能的唯一考虑因素;相反，越来越多的证据表明，为了更好地理解小胶质细胞在中枢神经系统生理中的作用，昼夜节律时间是一个必要的方面。
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原文信息
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主要内容
本综述将讨论描述小胶质细胞功能昼夜节律的研究。我们还将讨论为这些细胞提供时间戳的可能线索，以及这种昼夜节律调节的生理意义。最后，我们将提出昼夜节律时间作为研究生理和病理条件下小胶质细胞活动时需要考虑的一个新因素。
FIG1
Time of maximal clock gene expression map for BMAL1, PER1 and 2 and REV-ERB in the hippocampus (Hipp) and the cortex. Yellow panels indicate the light phase, and blue panels show the dark phase. ZT refers to Zeitgeber time, which literally means “provider of time” and refers to an environmental signal that indicates time, like the onset of light (ZT = 0)
FIG2
Circadian rhythm of microglia in the hippocampus and hypothalamus. Under physiological conditions, microglial genes are rhythmically expressed in the hippocampus and hypothalamus of rodents. In the hippocampus (a) CD11B+, CD68, CD45, Iba-1, IL-1β, TNF-α, and IL-6, are higher in the day than at night. Conversely, the microglial profile in the mediobasal hypothalamus (b) is inverted, with higher levels of Iba-1, and TNF-α during the night, in contrast, CD6 increases during the day
FIG3
Circadian differences in the microglial response to immune challenges. Hypothetical outcomes of an intraperitoneal (IP) lipopolysaccharide (LPS) administration and a traumatic brain injury (TBI) performed either during the light (resting) phase or at night (activity). In the resting phase, microglia expresses higher levels of pro-inflammatory cytokines which could contribute to the exacerbation of inflammation after an immune challenge. Instead, during the active phase microglia mainly express IL-10, which probably ameliorates the damage caused by either an LPS administration or a TBI
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文章背景
This study was supported by grants DGAPA-PAPIIT IA204121 to MAGR, DGAPA-PAPIIT IN221819 to RGG, DGAPA-PAPIIT IG201321 to RMB and DGAPA-PAPIIT IA206620 to NNGV, DGAPA-PAPIIT IN214821 to ACh, CONACyT Ciencia de Frontera-2019 1783 to ACh.
