Abstract
Aquaporin-4 (AQP4) is the water regulating channel found in the terminal processes of astrocytes in the brain and is implicated in regulating the astrocyte functions, whereas in neuropathologies, AQP4 performs an important role in astrocytosis and release of proinflammatory cytokines. However, several findings have revealed the modulation of the AQP4 water channel in the etiopathogenesis of various neuropsychiatric diseases. In the current article, we have summarized the recent studies and highlighted the implication of astrocytic dysfunction and AQP4 in the etiopathogenesis of depressive disorder. Most of the studies have measured the AQP4 gene or protein expression in the brain regions, particularly the locus coeruleus, choroid plexus, prefrontal cortex, and hippocampus, and found that in these brain regions, AQP4 gene expression decreased on exposure to chronic mild stress. Few studies also measured the peripheral AQP4 mRNA expression in the blood and AQP4 autoantibodies in the blood serum and revealed no change in the depressed patients in comparison with normal individuals.
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•AQP4 plays an important role in the regulation of astrocyte functions.•Modulation of AQP4 leads to astrocytic dysfunction and impairment in glymphatic system.•Astrocytes and AQP4 both are involved in hippocampal neurogenesis and synaptic plasticity.•Astrocytic dysfunction and AQP4 has been involved in the pathogenesis of depression.•Downregulation of AQP4 expression was found in the brain of the patients with depression.