MicroRNA29c Down-regulated APP? BACE1 Protein Expression In Alzheimer's Disease

Alzheimer's disease (AD) is a common neurodegenerative disease, which is characterized clinically by a progressive loss of memory and cognitive impairment.It was founded in 1907 by Alois Alzheimert,a Germany psychiatrist.Its main neuropathological features include diffuse loss of neurons in the hippocampus and neocortex, neurofibrillary tangles, accumulation of extracellular amyloid or senile plaques. Now pathogenesis about Alzheimer's disease haven't been clear. Though many hypothesis have been developed, such as APP metabolism, A?degradation and clearance, signal transduction,tau dysfunction, protein trafficking, cholinergic deficits, cholesterol metabolism and the homeostasis of heavy metals. But much hypothesis remains poorly defined neurodegenerative disease. Three gene involved in Alzheimer's disease:encode amyloid precursor protein (APP) and the presenilins (PSEN1 and PSEN2) founded in early-onset familial AD and one genetic risk factor for late-onset AD, the gene that encodes apolipoprotein E (APOE). We haven't known all the pathogenesis about AD and now no cure or preventative therapy yet are available. It is so necessory to find new pathogenesis and therapy for AD.microRNAs(miRNAs) are small,20-23 nucleotide noncoding RNAs that control gene expression at the posttranscriptional level by binding to the 3'untranslated region (3'UTR) of target mRNAs leading to their translational inhibition or sometimes degradation. Several miRNAs are specifically expressed or enriched in the brain, and some have been associated with neuronal differentiation, synaptic plasticity, and memory formation.The hypothesis that microRNA pathways could contribute to neurodegeneration is appealing. But now little research about microRNA and neurodegeneration relationship have been done. Using highly sensitive microarray-based procedures, we identified microRNA-29c increased in the 3,6,9 month-old APPswe/PS?E9 double-transgenic mouse brain, and then affirmed by real time PCR. In the APPswe/PS?E9 double-transgenic mouse brain higher mir-29c levels correlated with higher levels of APP protein. We choose 5 predicted gene- APP, BACE1, PI15, NAV3, PCDHA6 that may be targeted by microRNA-29c though miRBase?miRanda?PicTar and TargetScan database. We identified APP,BACE1,PI15, NAV3 protein decreased in higherly-expressed miR-29c SH-SY5Y cell line. Then we confirmed has-miR-29c can directly decreased APP, BACE1 protein expression by co-transfecting has-miR-29c and APP, BACE1 expression vector to HEK-293T cell line. In particular, APP and BACEl mRNA 3'UTRs can be binded by miR-29c at target sequences conserved across many vertebrates. In HEK-293T cell line, introduction of miR-29c inhibited expression of luciferase encoded by reporter vectors having the 3'UTRs of APP?NAV3these genes mRNA. Moreover, for each of several genes tested, mutating the miR-29c target sites in the APP 3'UTR abrogated miR-29c induced inhibition of luciferase expression and demonstrate there are at least two sites of the APP 3'UTR can be target by miR-29c. We have already developed the transgenic miR-29c mouse, and detect high-expression of miR-29c, and decreased APP and BACEl protein expression. Transgenic miR-29c mouse will surpport miR-29c research in vivo for further.Thus, We demonstrate that has-miR-29c can target APP and BACE1 gene expression in vitro and in vivo of transgenic miR-29c mouse.Has-miR-29c targeted genes-APP, BACE1 that are importantly associated with Alzheimer disease,miR-29c can be a new potential genetic therapy cue and new perspectives on the etiology of this neurological disorder.