Study On The Inhibitory Effects Of SRC Inhibitor On Aβ Toxicity In AD C.elegans And Its Mechanism

Alzheimer’s disease（AD）is a kind of neurodegenerative disease which lead to impaired mobility,cognition and memory.At present,the pathogenesis of AD is not clear.A general hypothesis that amyloid amino acid peptide Aβ_1-42-42 in the patient’s brain abnormal aggregation is the main pathogenesis of the disease.So far,there is still no effective drug to treat AD.Therefore,it is particularly important to design and screen effective drugs against Alzheimer’s disease.The role of Src tyrosine kinase expression has been identified in neurons recent years,and Src has a potential regulation mechanism between Aβdeposition and Tau protein in Alzheimer’s disease.We designed Src tyrosine protein kinase inhibitor as a target compound,named Y-11.In this study,we use AD mutant CL4176 C.elegans as an animal model to investigate the effect of Src inhibitor（Y-11）on delaying Aβdeposition in nematodes,as well as its mechanism of action.The results showed that Y-11 drug-fed worms displayed remarkably decreased paralysis,less Aβplaque deposition respect to untreated group.The effect concentration of Y-11 was in the descending order of 100μM>10μM>1μM.Therefore,we chose 100μM of Y-11 for the subsequent research.THT staining data showed that Y-11 dosing group significantly inhibited the deposition in the brain of nematodes.H₂DCF-DA fluorescence probe results suggested that Y-11 significantly reduced the content of ROS in nematodes.In order to find the mechanism of Y-11 on Aβtoxicity,Aβ,skn-1,hsf-1 and daf-16 gene expressions in mRNA levels were determined by real-time Quantitative PCR and actin-1 was used as keep-house gene.Genetic analyses showed that there was no significant difference in the relative expression of AβmRNA level between Y-11 group and the blank control group.It suggests that Y-11 reduced toxic protein deposition may regulate by post-transcription level,not transcription level.On contrary,the genes expression of hsf-1 and its downstream target gene hsp12.6 were significantly increased which revealed that Y-11 inhibition of Aβtoxicity may involve in hsf-1 signaling pathway in CL4176.Finally,our results showed that Y-11（100μM）treatment have no effect on the mean lifespan of worms and total egg production,but significantly enhance pumping rate and the survival rates under oxidative stresses.The results indicated that Y-11 can improve age-associated physiological functions in C.elegans.In addition,the 100μM could be used as a safe and effective drug concentration.In summary,we screened the Src inhibitor as a drug to anti-Alzheimer’s disease by CL4176 C.elegans.The results showed that Src inhibitor（Y-11）was able to inhibit the toxicity of Aβand significantly delay the paralysis of nematode.Moreover,this inhibition may be related to the ability of decrease the oxidative stress induced by Aβand may associate with hsf-1 signaling pathway.