AICAR improves depression-like behaviors and is associated with hippocampal AMPK activation and modulation of neurogenesis and neuroinflammation in a microbiota disruption model.
📄 Abstract
Gut microbiota alterations are associated with the onset of depression; however, the underlying mechanisms remain unclear. Activation of hippocampal AMP-activated protein kinase (AMPK) in ulcerative colitis mice with disrupted gut microbiota balance produces antidepressant effects. However, the relationship between hippocampal AMPK and antibiotic treatment (ABX)-induced depression-like behavior remains unclear. Therefore, we aimed to investigate whether 5-aminoimidazole-4-carboxamide 1-β-d-ribofuranoside (AICAR), an AMPK activator, is associated with the prevention of ABX-induced depression-like behaviors. ABX mice exhibited depression-like behaviors, as evidenced by prolonged immobility and reduced sucrose preference. In the hippocampus of the ABX mice, Iba1 and pro-inflammatory microglial markers were upregulated, whereas brain-derived neurotrophic factor (BDNF), CD206, arginase-1, and interleukin-10 were downregulated. Additionally, levels of AMPK phosphorylation, cAMP response element binding protein (CREB), and tropomyosin-related kinase B (TrkB) were decreased. AICAR administration attenuated these behavioral and molecular alterations. Phosphorylated AMPK was colocalized with the neuronal marker-NeuN-and microglial marker-Iba1. AICAR ameliorated the reduction in hippocampal neuron proliferation and survival and reduced microglial activation-associated morphological changes in the hippocampus. These findings suggest that AICAR administration is associated with antidepressant-like effects, potentially involving enhanced neurogenesis and attenuation of neuroinflammation in the hippocampus of ABX mice. Together, this study highlights the significance of hippocampal AMPK phosphorylation in depression associated with gut microbiota alterations, and suggests a potential target for therapeutic interventions.