Affective Immunology: The Crosstalk Between Microglia and Astrocytes Plays Key Role?

Abstract

Emerging evidence demonstrates the critical role of the immune response in the mechanisms relating to mood disorders, such as major depression (MDD) and bipolar disorder (BD). This has cast a spotlight on a specialized branch committed to the research of dynamics of the fine interaction between emotion (or affection) and immune response, which has been termed as "affective immunology." Inflammatory cytokines and gut microbiota are actively involved in affective immunology. Furthermore, abnormalities of the astrocytes and microglia have been observed in mood disorders from both postmortem and molecular imaging studies; however, the underlying mechanisms remain elusive. Notably, the crosstalk between astrocyte and microglia acts as a mutual and pivotal intermediary factor modulating the immune response posed by inflammatory cytokines and gut microbiota. In this study, we propose the "altered astrocyte-microglia crosstalk (AAMC)" hypothesis which suggests that the astrocyte-microglia crosstalk regulates emotional alteration through mediating immune response, and thus, contributing to the development of mood disorders.

Microbiota–Gut–Brain Axis and Epilepsy: A Review on Mechanisms and Potential Therapeutics

“…Gut microbes metabolize dietary tryptophan into aryl hydrocarbon receptor agonists and interact with its receptor to control microglial activation and TGF-α and VEGF-B expression, thereby modulating astrocyte pathogenic activity ( 81 , 82 ). Inflammatory cytokines and chemokines released by astrocytes enhance microglial activities, including migration, phagocytosis of apoptotic cells, and synaptic pruning ( 83 ). The interaction between astrocytes and microglia leads to increased pro-inflammatory cytokine production and BBB permeability, which results in the infiltration of peripheral blood immune cells and cytokines into the CNS, and subsequent chronic neuroinflammation ( 84 ).…”

Neonatal Rat Glia Cultured in Physiological Normoxia for Modeling Neuropathological Conditions In Vitro

“…Thus, neonatal astrocyte culturing might be useful for studying cell biology in conditions mimicking physiological microenvironment. These observations might be also valuable when planning disease-in-a-dish modeling, especially in the case of coculture experiments [ 69 , 70 , 71 ].…”

“…Establishing cocultures is an additional advantage to evaluate selected mechanisms of crosstalk between cells constituting neural tissue. Intercellular communication is essential for sustaining local homeostasis, neurodevelopmental processes, and tissue response to pathophysiological events [ 70 , 72 , 73 , 74 , 75 ]. The interplay between particular types of cells constituting the nervous tissue is crucial for overcome in inflammatory processes associated with disbalance in local microenvironment composition, promoting the initiation and enhancing neuroreparative processes [ 76 , 77 ].…”

What Guides Peripheral Immune Cells into the Central Nervous System?

“…Local resident inflammatory cells, id est astrocytes and microglia, are equipped with the molecular machinery to express and secrete chemokines and other pro-inflammatory cytokines [79][80][81][82]. Such cytokines can participate in the activation of endothelial cells, paving the way for peripheral immune cell recruitment into the brain parenchyma.…”