MiR-124 Regulates Cerebromicrovascular Function In APP/PS1 Transgenic Mice Via C1ql3

Background and Objective:Alzheimer's disease(AD)is a neurodegenerative disease which is characterized by progressive memory loss.But the cellular and molecular basis are not clear.Many neurodegenerative diseases,such as Alzheimer's disease(AD)and Parkinson's disease,have microvascular changes in brain.This suggests that the pathogenesis of these diseases may be associated with microvascular dysfunction.Some studies found that microvascular changes precede other pathological changes in Alzheimer's disease.Recently,microRNAs(miRNAs)have been suggested to be involved in the microvascular dysfunction and subsequent memory impairment.MicroRNA-124(miR-124)is one of the most abundant miRNAs in the brain that is dysregulated in the hippocampus of AD animals.miR-124 could regulate AD via A? and APP.In addition,some studies showed that miR-124 has involved in a variety of vascular diseases.But its role in the microvasculature of Alzheimer's disease is still poor understood.Recent studies have found that complement protein C1 q plays a role in many neurodegenerative diseases.To explore the role of miR-124 in AD pathology,we employed the APP/PS1 transgenic mice and found altered expressions of miR-124 and complement C1q-like protein 3(C1ql3)in the hippocampus and cerebral cortex,and detecting vascular and behavioral changes in all groups.Methods: 1.Treatment with lentivirus-mediated overexpression of miR-124 in AD mice as AD group and inhibition of C1ql3 by injecting C1INH(C1ql3 functional inhibitor)into lateral ventricles;2.Quantitative polymerase chain reaction(qPCR)was used to detect the changes of the mRNA of miR-124 and C1ql3 in the control group,AD group,C1 INH group and miR-124 group;3.The density of cerebral microvessels,the changes of angiogenesis and blood-brain barrier were measured by immunofluorescence and western blot;accumulation of A? was detected by immunohistochemical;4.Morris water maze(MWM)was conducted to evaluate spatial learning and memory in the control group,AD group,C1 INH group and mir-124 group.Results: 1.compared with the control group,miR-124 in the hippocampus and cortex of the AD group was decreased,while the level of C1ql3 was significantly increased.Compared with the AD group,C1ql3 was decreased in the hippocampus and cortex of the mice in the miR-124 overexpression group.2.Compared with the AD group,the escape latency of miR-124 and C1ql3 group in the Morris water maze test was significantly shortened,and the proportion of duration in the target quadrant of the platform was significantly increased(P< 0.05).3.The results of immunofluorescence detection showed that,compared with the control group,the CD31,TIE-2 and CD34 were reduced in the hippocampus and cortex respective in the AD group,indicating density of vessels was decline.In the C1 INH group,CD31 and TIE-2 were increased in hippocampus and cortex.And CD34 was also increased in miR-124 group.ZO-1 and CD31/GFAP were decreased in AD group,indicating that the BBB was impaired and the damage was significantly reduced in C1 INH group and miR-124 group.Compared with the control group,CD105 was decreased in the hippocampus of AD mice brain,which indicated the decrease of angiogenesis,while it was rescued in the C1 INH group and the miR-124 group.4.The detection results of western blot showed that,compared with the control group,CD31,TIE-2 and CD34 in the hippocampus of AD group mice were decreased,while the CD31,TIE-2 and CD34 in the C1 INH group and miR-124 group were increased compared with AD group.ZO-1 and CD31/GFAP were decreased in AD group,but increased in C1 INH group and miR-124 group.Compared with the control group,CD105 decreased in the hippocampus of the AD group,while the C1 INH group and mir-124 group showed different degrees of remission.5.Immunohistochemical results showed that compared with the control group,the A? in the AD group were increased,while those in the C1 INH and mir-124 groups were slightly reduced.Conclusion: 1?we found that C1ql3 might be a potential target of miR-124,and could be regulated by miR-124.2.Upregulation of miR-124 or inhibition of C1ql3 expression can also alleviated spatial learning and memory deficit in APP/PS1 mice.3?Dysregulation of miR-124 expression resulted in A? deposition and a variety of cerebromicrovascular impairments,including the decline in microvascular density,reduced angiogenesis,accompanied by C1ql3 alteration.Treatment with lentivirus-mediated overexpression of miR-124 or the C1 q inhibitor C1 INH rescued breakdown of blood-brain barrier.And miR-124 was involved in the angiogenesis and vascular integrity in the hippocampus and the cerebral cortex of the AD mice by regulating the classical complement C1ql3.