Alzheimer's disease (AD) is a progressive neurodegenerative disease in which patients exhibit gradual loss of memory that impairs their ability to learn or carry out daily tasks. Diagnosis of AD is difficult, particularly in early stages of the disease, and largely consists of cognitive assessments, with only one in four patients being correctly diagnosed. Development of novel therapeutics for the treatment of AD has proved to be a lengthy, costly and relatively unproductive process with attrition rates of > 90%. As a result, there are no cures for AD and few treatment options available for patients. Therefore, there is a pressing need for drug discovery platforms that can accurately and reproducibly mimic the AD phenotype and be amenable to high content screening applications. Here, we discuss the use of induced pluripotent stem cells (iPSCs), which can be derived from adult cells, as a method of recapitulation of AD phenotype in vitro . We assess their potential use in high content screening assays and the barriers that exist to realising their full potential in predictive efficacy, toxicology and disease modelling. At present, a number of limitations need to be addressed before the use of iPSC technology can be fully realised in AD therapeutic applications. However, whilst the use of AD-derived iPSCs in drug discovery remains a fledgling field, it is one with immense potential that is likely to reach fruition within the next few years.© 2014 Baishideng Publishing Group Co., Limited. All rights reserved.Key words: Human induced pluripotent stem cells; Alzheimer's disease; Neurodegenerative diseases; Highthroughput screening assays; Cholinergic neurons; Drug discovery; Stratified medicine Core tip: Alzheimer's disease (AD) affects 36 million people worldwide and is set to double by 2030. Progress in understanding AD has been hindered by a lack of suitable in vitro and in vivo models reflected in > 90% drug attrition rates. Induced pluripotent stem cells are an alternative source of neural cells that can be derived from patients' somatic cells and exhibit AD pathophysiological phenotypes. These cells are amenable to HTS formats required for drug discovery applications. Harnessing this combined potential would provide an unprecedented opportunity to significantly reduce timeframes and costs associated with developing novel therapeutics, ultimately improving patient outcomes.Mohamet L, Miazga NJ, Ward CM. Familial Alzheimer's disease modelling using induced pluripotent stem cell technology. World J Stem Cells 2014; 6(2): 239-247 Available from:

Mouse embryonic stem cells (mESCs) and epiblast stem cells represent the na€ ıve and primed pluripotent states, respectively. These cells self-renew via distinct signaling pathways and can transition between the two states in the presence of appropriate growth factors. Manipulation of signaling pathways has therefore allowed the isolation of novel pluripotent cell types such as Fibroblast growth factor, Activin and BIO-derived stem cells and IESCs. However, the effect of cell seeding density on pluripotency remains unexplored. In this study, we have examined whether mESCs can epigenetically regulate E-cadherin to enter a primed-like state in response to low cell seeding density. We show that low density seeding in the absence of leukaemia inhibitory factor (LIF) induces decreased apoptosis and maintenance of pluripotency via Activin/Nodal, concomitant with loss of E-cadherin, Signal transducer and activator of transcription phosphorylation, and chimera-forming ability. These cells, E-cadherin negative proliferating stem cells (ENPSCs) can be reverted to a na€ ıve phenotype by addition of LIF or forced E-cadherin expression. However, prolonged culture of ENPSCs without LIF leads to methylation of the E-cadherin promoter (ENPSC M ), which cannot be reversed by LIF supplementation, and increased histone H3K27 and decreased H3K4 trimethylation. Transcript analysis of ENPSC M revealed a primed-like phenotype and their differentiation leads to enrichment of neuroectoderm cells. The generation of ENPSCs is similar to tumorigenesis as ENPSCs exhibit transcript alterations associated with neoplasia, hyperplasia, carcinoma, and metastasis. We therefore describe a novel cell model to elucidate the role of Ecadherin in pluripotency and to investigate epigenetic regulation of this gene during mESC differentiation and tumor metastasis.