JWX-a0108,a Positive Allosteric Modulator Of α7 NAChR,alleviates Cognitive Impairment In APP/PS1 Mice By Inhibiting Inflammatory Response

Alzheimer’s disease(AD)is the most common of the neurodegenerative diseases among the aging population,characterized by progressive memory impairment,significant cognitive deficits and irreversible changes in personality and behavior.Although the specific molecular and cellular mechanisms responsible for the etiology and pathogenesis of AD have not been defined,research has revealed that the main pathological characteristics of AD are amyloid-β(Aβ)aggregation and the hyperphosphorylation of tau protein,which eventually develop into senile plaque and neurofibrillary tangles.Together with inflammation and oxidative stress,these pathological cascades contribute to the decline of cholinergic function in the brain.Cholinergic anti-inflammatory pathway(CAP)indicates that acetylcholine(ACh)can inhibit inflammation by acting on nicotinic acetylcholine receptors(nAChRs)on the surface of macrophages,especially α7 nAChR.This receptor belongs to the super family of pentameric ligand-gated ion channels.It is a homopentamer composed of five α7subunits and has high permeability to calcium ions.The α7 nAChR-Aβ complex in the brain leads to the aggravation of inflammatory environment and serious damage α7nAChR.There are two main ligand binding sites of α7 nAChR,namely agonist/antagonist binding sites and allosteric regulatory sites.Activation of receptor by agonists induces calcium influx,with fast desensitization and off-target effects.Positive allosteric modulator(PAM)of α7 nAChR with low intrinsic activity,only increased calcium influx in the presence of endogenous ACh,and it is not easy to desensitize and with specific targeting.The α7 nAChR PAMs have been classified into two categories: type I and type II.Type I PAMs increase peak current in the presence of an orthosteric agonist without affecting receptor desensitization.Type II PAMs,on the other hand,significantly reduce the fast desensitization of α7 nAChRs.JWX-A0108 is a new type I PAM of α7 nAChR developed and synthesized by our laboratory independently.Previous experiments have proved that JWX-A0108 can significantly increase the excitatory effect of ACh on α7 nAChR,increase the spontaneous discharge of hippocampus,it can specifically target α7 nAChR and the physiological effects of other nAChR subtypes were not affected.Objective: In this study,APP/PS1 double transgenic mice were used to evaluate the pharmacodynamics of JWX-A0108.To confirm whether JWX-A0108 can improve cognitive impairment in APP/PS1 mice and explore its mechanism.To provide experimental basis for the research and development of drugs for the treatment of AD.Methods:1.Morris water maze was used to detect the effect of JWX-A0108 on the cognitive and memory function of nine months old APP/PS1 transgenic mice.2.Nissl staining was used to detect the effect of JWX-A0108 on hippocampal neurons in nine months old APP/PS1 transgenic mice.3.Western Blot and immunofluorescence were used to detect the effect of JWX-A0108 on microglia in nine months old APP/PS1 transgenic mice.4.q RT-PCR and Western Blot were used to detect the effects of JWX-A0108 on inflammatory factors in the brain of nine months old APP/PS1 transgenic mice.5.Western Blot was used to detect the activation of NF-κB pathway.Results:1.JWX-A0108(5 mg/kg,ip)improved the cognitive impairment of APP/PS1 mice.2.JWX-A0108(5 mg/kg,ip)improved the pathological damage of hippocampal CA3 area,such as loose cell arrangement and decreased Nissl body expression.3.JWX-A0108(5 mg/kg,ip)decreased the expression of Iba1 in microglia.4.JWX-A0108(5 mg/kg,ip)decreased the expression of IL-1β,TNF-α and IL-6 in cerebral cortex and hippocampus of APP/PS1 mice.5.JWX-A0108(5 mg/kg,ip)inhibited the phosphorylation of NF-κB p65,IκBα and the activation of NF-κB,the effects of JWX-A0108 were blocked by MLA,a specific α7nAChR blocker.Conclusions:JWX-A0108 can significantly improve the learning and cognitive function of APP/PS1 mice by enhancing the activation of endogenous ACh on α7 nAChR,thus inhibiting the over-activation of the NF-κB pathway in microglia and reducing the inflammatory responses.