Ganoderic Acid A Attenuates LPS-Induced Neuroinflammation in BV2 Microglia by Activating Farnesoid X Receptor.

Neuroinflammation plays an important role in the onset and progression of neurodegenerative diseases. Microglia-mediated neuroinflammation have been proved to be the main reason for causing the neurodegenerative diseases. Ganoderic acid A (GAA), isolated from Ganoderma lucidum, showed anti-inflammatory effect in metabolism diseases. However, little research has been focused on the effect of GAA in neuroinflammation and the related mechanism. In the present study, lipopolysaccharide(LPS)-stimulated BV2 microglial cells were used to evaluate the anti-inflammatory capacity of GAA. Our data showed that GAA significantly suppressed LPS-induced BV2 microglial cells proliferation and activation in vitro. More strikingly, GAA promoted the conversion of BV2 microglial cells from M1 status induced by LPS to M2 status. Furthermore, GAA inhibited the pro-inflammatory cytokines release and promoted neurotrophic factor BDNF expression in LPS-induced BV2 microglial cells. Finally, we found that the expression of farnesoid-X-receptor (FXR) was prominently downregulated in LPS-stimulated BV2 microglial cells, antagonism of FXR with z-gugglesterone and FXR siRNA can reverse the effect of GAA in LPS-induced BV2 microglial cells. Taking together, our findings demonstrate that GAA can significantly inhibit LPS-induced neuroinflammation in BV2 microglial cells via activating FXR receptor.

A Polysaccharide Extract from Maitake Culinary-Medicinal Mushroom, Grifola frondosa (Agaricomycetes) Ameliorates Learning and Memory Function in Aluminum Chloride-Induced Amnesia in Mice.

Maitake (Grifola frondosa) is an edible mushroom exhibiting high nutritional value in terms of containing health-beneficial bioactive compounds. Previously, we reported that a protein-bound polysaccharide bioactive component of G. frondosa (PGM) could enhance the expression of α-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid receptor (AMPAR), which is critical for learning and memory. However, the potential benefits of PGM on learning and memory function have never been investigated. In the current study, we aimed to explore the beneficial effect of PGM on learning and memory function in aluminum chloride (AlCl3)-induced amnesia in mice and to explore the underlying mechanisms. Mice were intraperitoneally administered with AlCl3 (60 mg/kg/d) and PGM (5, 10, or 20 mg/kg/d) for 6 weeks consecutively, and then the Morris water maze (MWM) test was conducted to assess the learning and memory function. Hematoxylin-eosin staining was performed to observe the morphology of neurons in the hippocampal dentate gyrus (DG). The expression of p-Tau (Ser396), Tau, p-GluA1 (S845), GluA1, and brain-derived neurotrophic factor (BDNF) proteins was evaluated with western blot. We found that PGM (5 and 10 mg/kg/d) significantly improved learning and memory function and attenuated histopathological abnormalities in the hippocampal DG region in the AlCl3-treated mice. Furthermore, PGM treatment significantly enhanced the level of AMPAR and BDNF in the hippocampus, while suppressing the tau protein hyperphosphorylation at the Ser396 site. These findings indicated that PGM could significantly attenuate the AlCl3-induced amnesia through the synergistic action of its active component on tau pathology, AMPAR and BDNF signaling pathway.

Griflola frondosa (GF) produces significant antidepressant effects involving AMPA receptor activation in mice.

CONTEXT: Griflola frondosa (Fr) S.F. Gray (Meripilaceae) (GF) is a medical mushroom, and its regulation of the immune system is of interest for the treatment of mood disorders. α-Amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid (AMPA) receptors are the central mediator for the treatment of depression. OBJECTIVE: This study examines the antidepressant effects of GF and the role of AMPA in these antidepressant effects. MATERIALS AND METHODS: The CD-1 mice were fed with GF- or Pleurotus ostreatus [(Jacq.: Fr) Kumm (Pleurotaceae)] (PO)-containing food for 1 day or 5 days. The antidepressant effects was determined in the tail suspension test (TST), forced swim test (FST), and open field test (OFT). The involvement of AMPA receptors was determined by the application of the AMPA-specific blocker GYKI 52466. RESULTS: Treatments with 20%, 33% or 50% of GF-containing food significantly decreased the immobility time (63.6, 56.9, and 52.0% in TST; and 50.8, 43.2, and 38.2% in FST) after 1 day and (62.3, 51.8, and 52.8% in TST; and 49.5, 45.1, and 40.3% in FST) after 5 days. GF-containing food did not cause hyperactive effects in the OFT. The antidepressant effects of the 33% of GF-containing food (down-to 51.3% in 1-day TST and 46.8% in 5-day FST) were significantly stronger than that of the 33% of PO-containing food (down-to 85.5% in 1-day TST and 82.0% in 5-day FST). AMPA-specific blocker GYKI 52466 was able to block the antidepressant effects of the GF-containing food. CONCLUSION: GF demonstrated the potential as a safe medical food supplement for the patient with depression.

The Role of Nutrients in Protecting Mitochondrial Function and Neurotransmitter Signaling: Implications for the Treatment of Depression, PTSD, and Suicidal Behaviors.

Numerous studies have linked severe stress to the development of major depressive disorder (MDD) and suicidal behaviors. Furthermore, recent preclinical studies from our laboratory and others have demonstrated that in rodents, chronic stress and the stress hormone cortisol cause oxidative damage to mitochondrial function and membrane lipids in the brain. Mitochondria play a key role in synaptic neurotransmitter signaling by providing adenosine triphosphate (ATP), mediating lipid and protein synthesis, buffering intracellular calcium, and regulating apoptotic and resilience pathways. Membrane lipids are similarly essential to central nervous system (CNS) function because cholesterol, polyunsaturated fatty acids, and sphingolipids form a lipid raft region, a special lipid region on the membrane that mediates neurotransmitter signaling through G-protein-coupled receptors and ion channels. Low serum cholesterol levels, low antioxidant capacity, and abnormal early morning cortisol levels are biomarkers consistently associated with both depression and suicidal behaviors. In this review, we summarize the manner in which nutrients can protect against oxidative damage to mitochondria and lipids in the neuronal circuits associated with cognitive and affective behaviors. These nutrients include ω3 fatty acids, antioxidants (vitamin C and zinc), members of the vitamin B family (Vitamin B12 and folic acid), and magnesium. Accumulating data have shown that these nutrients can enhance neurocognitive function, and may have therapeutic benefits for depression and suicidal behaviors. A growing body of studies suggests the intriguing possibility that regular consumption of these nutrients may help prevent the onset of mood disorders and suicidal behaviors in vulnerable individuals, or significantly augment the therapeutic effect of available antidepressants. These findings have important implications for the health of both military and civilian populations.