Progress of Alzheimer＇s disease related glucose metabolism regulating hormones and a research perspective in nootropics of herbal medicine

阿尔茨海默病是一种神经退行性疾病,但其发病机制尚不清楚.有证据表明糖尿病与阿尔茨海默病发病有关,而糖尿病发病的的根本原因是糖代谢异常.因此糖代谢调节激素和阿尔茨海默病之间可能存在不可分离的关系.作者综述了糖代谢调节激素与阿尔茨海默病发病机制的相关研究进展,并基于此对益智中药研究提出了新思路.

Ginsenoside Rg1 protects against ischemia reperfusion-induced neurotoxicity through miR-144/Nrf2/ARE pathway

OBJECTIVE Ginsenoside Rg1(Rg1),a purified compound from Panax ginseng,has been well documented to be effective against ischemia/reperfusion(I/R) neurotoxicity.However,the underlying mechanism is stil obscure.METHODS The anti-I/R effect of Rg1 were investigated in vitro and in vivo,and the dynamics of nuclear accumulation and the transcriptional activity of NF-E2-related factor 2(Nrf2) determined by Western blotting and Dual Luciferase Reporter Assay,respectively.Nrf2 siRNA was employed to investigate Nrf2′s role in the protective effect of Rg1 against I/R.Furthermore,the role of miR-144,which could regulate post-translational Nrf2 levels,was investigated in the anti-I/R effect of Rg1 by injection of AAV-hypoxia-inducible factor miR-144-shRNA in the predicted ischemic penumbra.RESULTS It was found that the anti-I/R effect of Rg1 was related to its anti-oxidative capacity,which is mainly regulated by the Nrf2/antioxidant response element(ARE) pathway.Further study suggested that Rg1 contributes to the enhancement of the Nrf2/ARE pathway,as manifested by increasing the dynamic peak content of Nrf2,which prolonged the maintenance stage,and promoting the expression of ARE-target genes after oxygen glucose deprivation/reperfusion(OGD/R) in PC12 cells.Nrf2-siRNA application significantly reduced these changes.Furthermore,the enhancement of the Nrf2/ARE pathway by Rg1 was independent of disassociation from Keap1;rather it was a result of posttranslational regulations.It was found that Rg1 significantly reduced the expression of miR-144,which down-regulates Nrf2 production by targeting its 3′-untranslated region,after OGD/R.Knockdown of Nrf2 showed no effect on the expression of miR-144,indicating that miR-144 is an upstream regulator of Nrf2.Moreover,direct binding between Nrf2 and miR-144 in the PC12 cells was identified.Application of anti-miR-144 significantly reduced Rg1′s anti-OGD/R capacity.Final y,the role of miR-144 in Rg1′ s anti-I/R effect was tested by inhibiting miR-144 in the predicted ischemic penumbra when hypoxia-inducible-factor was activated.The results showed that loss of miR-144 abolished the anti-I/R effect of Rg1,which included reduced infarct volume,improved neurological scores,attenuated oxidative impairment,as well as activation of the Nrf2/ARE pathway.CONCLUSION Oxidative stress after I/R is alleviated by Rg1 through inhibition of miR-144 activity and subsequent promotion of the Nrf2/ARE pathway at the post-translational level.

Protein kinase-based neural signaling pathways for ginsenosides:a retrospective review

Ginsenosides are the main active components of ginseng,which have been reported to target brain tissues and produce multiple neuroprotective effects.Ginsenosides have been shown to improve learning ability and memory in normal aged animals,and in an animal model of memory impairment.However,its underlying pharmacological mechanisms are very complicated,especially with regard to its effects on the activation of protein kinases in neurons.Previous reports have shown that some protein kinases may be affected by ginsenosides,including protein kinase C,calcium/calmodulin-dependent protein kinase Ⅱ,c-Jun-N terminal kinase,and protein tyrosine kinase.In this paper,protein kinases that may underlie the mechanisms of ginsenosides will be discussed.