Deletion of Type-2 Cannabinoid Receptor Induces Alzheimer's Disease-Like Tau Pathology and Memory Impairment Through AMPK/GSK3ß Pathway.

Although several studies have shown that type-2 cannabinoid receptor (CB2R) is involved in Alzheimer's disease (AD) pathology, the effects of CB2R on AD-like tau abnormal phosphorylation and its underlying mechanism remain unclear. Herein, we employed the CB2R-/- mice as the animal model to explore roles of CB2R in regulating tau phosphorylation and brain function. We found that CB2R-/- mice display AD-like tau hyperphosphorylation, hippocampus-dependent memory impairment, increase of GSK3ß activity, decrease of AMPK and Sirt1 activity and mitochondria dysfunction. Interestingly, AICAR or resveratrol (AMPK agonist) could efficiently rescue most alternations caused by solo deletion of CB2R in CB2R-/- mice. Moreover, JWH133, a selective agonist of CB2R, reduces phosphorylation of tau and GSK3ß activity in HEK293 tau cells, but the effects of JWH133 on phosphorylation of tau and GSK3ß disappeared while blocking AMPK activity with compound C or Prkaa2-RNAi. Taken together, our study indicated that deletion of CB2R induces behavior damage and AD-like pathological alternation via AMPK/GSK3ß pathway. These findings proved that CB2R/AMPK/GSK3ß pathway can be a promising new drug target for AD.

Transient Receptor Potential-canonical 1 is Essential for Environmental Enrichment-Induced Cognitive Enhancement and Neurogenesis.

Transient receptor potential-canonical 1 (TRPC1) plays a crucial role in neuronal survival, nerve regeneration, and protects neurons from neurotoxic injury, but it is not reported whether or how TRPC1 may affect learning and memory. Here, we found that TRPC1 knockout did not significantly affect the spatial learning and memory ability when the mice were housed in standard cages (SC). Interestingly, after the mice were exposed to environmental enrichment (EE) for 4 weeks, TRPC1 knockout abolished the EE-induced spatial memory enhancement, LTP induction, and neurogenesis in hippocampal DG subset. By stereotaxic infusion of the recombinant adeno-associated viruses (rAAV)-TRPC1 into the hippocampal DG subsets bilaterally, we observed that the EE-associated neurogenesis, LTP induction and the cognitive enhancement were efficiently rescued in TRPC1 knockout mice. EE increased the phosphorylation levels of ERK, p38, and cyclic AMP response element-binding protein (CREB) in wild-type mice, whereas the activation of ERK and CREB was not seen in TRPC1 knockout mice, and the phosphorylation of p38 was same in EE-TRPC1-/- and WT-EE. Finally, EE increased TRPC1 expression and overexpression of TRPC1 increased neurogenesis and activated ERK/CREB pathway in the wild-type mice. These findings suggest that TRPC1 is indispensable for the EE-induced hippocampal neurogenesis and cognitive enhancement.

[The effects of Shadu Cao Mixture on immune functions of immunosuppression mice].

OBJECTIVE: To investigate the effects of Shadu Cao Mixture (SDCM, traditional Chinese medicine) on immune functions of immunosuppression mice. METHODS: Fifty BALB/C mice were randomly divided into blank control group, model group, SDCM low-dose, middle-dose and high-dose group. Except the blank control group, other groups were intraperitoneal injected with cyclophosphamide (40 mg/kg) to establish immunosuppression mice model. The blank control group and model group received gavage administration with nonnal saline, while the other groups received gavage administration with different doses of SDCM (10, 20, 40 m/kg for 15 days) respectively. The number of leukocytes and serum levels of interleukin-2 (IL-2), tumor necrosis factor-α (TNF-α) and interferon-γ (IFN-γ) in peripheral blood, spleen index, and the function of NK cells were measured. RESULTS: Compared with the model group , SDCM increased the number of leukocytes and serum concentrations of IL-2, TNF-α and IFN-γ in peripheral blood and improved the spleen index and the function of NK cells significantly (P < 0.05-0.01). CONCLUSION: SDCM could remarkably enhance the immune functions of immunosuppression mice induced by cyclophosphamide.