AUTHOR=Guzmán-Ruíz Mara A. , Guerrero Vargas Natalí N. , Ramírez-Carreto Ricardo Jair , González-Orozco Juan Carlos , Torres-Hernández Bryan Adair , Valle-Rodríguez Michelle , Guevara-Guzmán Rosalinda , Chavarría Anahí TITLE=Microglia in physiological conditions and the importance of understanding their homeostatic functions in the arcuate nucleus JOURNAL=Frontiers in Immunology VOLUME=15 YEAR=2024 URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2024.1392077 DOI=10.3389/fimmu.2024.1392077 ISSN=1664-3224 ABSTRACT=

Microglia are highly dynamic cells that have been mainly studied under pathological conditions. The present review discusses the possible implication of microglia as modulators of neuronal electrical responses in physiological conditions and hypothesizes how these cells might modulate hypothalamic circuits in health and during obesity. Microglial cells studied under physiological conditions are highly diverse, depending on the developmental stage and brain region. The evidence also suggests that neuronal electrical activity modulates microglial motility to control neuronal excitability. Additionally, we show that the expression of genes associated with neuron-microglia interaction is down-regulated in obese mice compared to control-fed mice, suggesting an alteration in the contact-dependent mechanisms that sustain hypothalamic arcuate-median eminence neuronal function. We also discuss the possible implication of microglial-derived signals for the excitability of hypothalamic neurons during homeostasis and obesity. This review emphasizes the importance of studying the physiological interplay between microglia and neurons to maintain proper neuronal circuit function. It aims to elucidate how disruptions in the normal activities of microglia can adversely affect neuronal health.