AB3252 Sigma-AldrichAnti-c-myc Antibody

Human induced pluripotent stem (iPS) cells have great value for regenerative medicine, but are facing problems of low efficiency. MicroRNAs are a recently discovered class of 19-25 nt small RNAs that negatively target mRNAs. miR302/367 cluster has been demonstrated to reprogram mouse and human somatic cells to iPS cells without exogenous transcription factors, however, the repetition and differentiation potentiality of miR302/367-induced pluripotent stem (mirPS) cells need to be improved. Here, we showed overexpression of miR302/367 cluster reprogrammed human embryonic kidney 293T cells into mirPS cells in serum-free N2B27-based medium. The mirPS cells had similar morphology with embryonic stem cells, and expressed pluripotent markers including Oct4, Sox2, Klf4, and Nanog. In addition, through formation of embryoid bodies, various cells and tissues from three germ layers could be determined. Moreover, we examined the potential of mirPS cells differentiating into germ cells both in vitro and in vivo. Taken together, these data might provide a new source of cells and technique for the investigation of the mechanisms underlying reprogramming and pluripotency.

The generation of the amyloid-beta peptide (Abeta) through the proteolytic processing of the amyloid precursor protein (APP) is a central event in the pathogenesis of Alzheimer's disease (AD). Recent studies highlight APP endocytosis and localization to lipid rafts as important events favoring amyloidogenic processing. However, the precise mechanisms underlying these events are poorly understood. ApoER2 is a member of the low density lipoprotein receptor (LDL-R) family exhibiting slow endocytosis rate and a significant association with lipid rafts. Despite the important neurophysiological roles described for ApoER2, little is known regarding how ApoER2 regulates APP trafficking and processing.Here, we demonstrate that ApoER2 physically interacts and co-localizes with APP. Remarkably, we found that ApoER2 increases cell surface APP levels and APP association with lipid rafts. The increase of cell surface APP requires the presence of ApoER2 cytoplasmic domain and is a result of decreased APP internalization rate. Unexpectedly, ApoER2 expression correlated with a significant increase in Abeta production and reduced levels of APP-CTFs. The increased Abeta production was dependent on the integrity of the NPxY endocytosis motif of ApoER2. We also found that expression of ApoER2 increased APP association with lipid rafts and increased gamma-secretase activity, both of which might contribute to increased Abeta production.These findings show that ApoER2 negatively affects APP internalization. However, ApoER2 expression stimulates Abeta production by shifting the proportion of APP from the non-rafts to the raft membrane domains, thereby promoting beta-secretase and gamma-secretase mediated amyloidogenic processing and also by incrementing the activity of gamma-secretase.