Decreased connexin43 expression in the hippocampus is related to the antidepressant effect of amitriptyline in neuropathic pain mice

Astroglial Connexin 43-Mediated Gap Junctions and Hemichannels: Potential Antidepressant Mechanisms and the Link to Neuroinflammation

Major depression disorder (MDD) is a neuropsychiatric disorder associated with a high suicide rate and a higher disability rate than any other disease. Evidence suggests that the pathological mechanism of MDD is related to astrocyte dysfunction. Depression is mainly associated with the expression of connexin 43 (Cx43) and the function of Cx43-mediated gap junctions and hemichannels in astrocytes. Moreover, neuroinflammation has been a hotspot in research on the pathology of depression, and Cx43-mediated functions are thought to be involved in neuroinflammation-related depression. However, the specific mechanism of Cx43-mediated functions in neuroinflammation-related depression pathology remains unclear. Therefore, this review summarizes and discusses Cx43 expression, the role of gap junction intercellular communication, and its relationship with neuroinflammation in depression. This review also focuses on the effects of antidepressant drugs (e.g., monoamine antidepressants, psychotropic drugs, and N-methyl-D-aspartate receptor antagonists) on Cx43-mediated function and provides evidence for Cx43 as a novel target for the treatment of MDD. The pathogenesis of MDD is related to astrocyte dysfunction, with reduced Cx43 expression, GJ dysfunction, decreased GJIC and reduced BDNF expression in the depressed brain. The effect of Cx43 on neuroinflammation-related depression involving inflammatory cytokines, glutamate excitotoxicity, and HPA axis dysregulation. Antidepressant drugs targeting Cx43 can effectively relieve depressive symptoms.

Mahonia Alkaloids (MA) Ameliorate Depression Induced Gap Junction Dysfunction by miR-205/Cx43 Axis

Depression has become an important disease threatening human health. In recent years, the efficacy of Traditional Chinese Medicine (TCM) in treating the disease has become increasingly prominent, so it is meaningful to find new antidepressant TCM. Mahonia fortune (Lindl.) Fedde is a primary drug in traditional formulas for the treatment of depression, and alkaloids are the main components of it. However, the detailed mechanism of Mahonia alkaloids (MA) on depression remains unclear. This study aimed to investigate the effect of MA on gap junction function in depression via the miR-205/Cx43 axis. The antidepressant effects of MA were observed by a rat model of reserpine-induced depression and a model of corticosterone (CORT)-induced astrocytes. The concentrations of neurotransmitters were measured by ELISA, the expression of Connexin 43 (Cx43) protein was measured by Immunohistochemistry and western-blot, brain derived neurotrophic factor (BDNF), cAMP-response element binding protein (CREB) proteins were measured by western-blot, the pathological changes of prefrontal cortex were observed by hematoxylin-eosin (H&E) staining. Luciferase reporter assay was performed to verify the binding of miR-205 and Cx43. The regulation effect of Cx43 on CREB was verified by interference experiment. Gap junction dysfunction was detected by fluorescent yellow staining. The results confirmed that MA remarkably decreased miR-205 expression and increased Cx43, BDNF, CREB expression in depression rat and CORT-induced astrocytes. In addition, after overexpression of miR-205 in vitro, the decreased expression of Cx43, BDNF and CREB could be reversed by MA. Moreover, after interfering with Cx43, the decreased expression of CREB and BDNF could be reversed by MA. Thus, MA may ameliorate depressive behavior through CREB/BDNF pathway regulated by miR-205/Cx43 axis.