Background Alzheimer’s disease (AD) is a neurodegenerative disorder that causes progressive

Background Alzheimer’s disease (AD) is a neurodegenerative disorder that causes progressive memory and cognitive decline during middle to late adult life. conditioned ATB 346 media. Aβ production was inhibited by β-secretase inhibitor γ-secretase inhibitor (GSI) and an NSAID; however there were different susceptibilities to all three drugs between early and late ATB 346 differentiation stages. At the early differentiation stage GSI treatment caused a fast increase at lower dose (Aβ surge) and drastic decline of Aβ production. Conclusions/Significance These results indicate that the hiPS cell-derived neuronal cells express functional β- and γ-secretases involved in Aβ production; however anti-Aβ drug screening using these hiPS cell-derived neuronal cells requires sufficient neuronal differentiation. Introduction Alzheimer’s disease (AD) is the most common cause of dementia in the elderly. It is characterized clinically by progressive declines in IL5RA memory executive function and cognition. It is also characterized by pathological features including the deposition of amyloid plaques and neurofibrillary tangles as well as neuronal and synaptic loss in particular areas of the brain [1]. Accumulation of amyloid β peptide (Aβ) is hypothesized to initiate the pathogenic cascade that eventually leads to AD. The amyloid hypothesis is based on an imbalance ATB 346 between the production and clearance of Aβ [2]. Aβ is produced by β- and γ-secretase-mediated sequential proteolysis of amyloid precursor protein (APP) and plays a central role in AD pathogenesis. Because β- and γ-secretases are directly involved in Aβ production they are ATB 346 straightforward and attractive therapeutic targets for AD. A number of compounds that inhibit or modulate these secretase activities and Aβ levels and have to date been developed [3] [4]. Development of a human cell-based assay system is a basic requisite for drug discovery and for investigating mechanisms of the disease. Induced pluripotent stem (iPS) cells reprogrammed from somatic cells [5] [6] provide an opportunity to easily generate and use patient-specific differentiated cells. Because previous AD assay systems using human cancer cell lines or primary rodent cell cultures did not perfectly present the human intracellular environment or components human iPS (hiPS) cell-derived neuronal cells may enable the development of more efficient drugs such as γ-secretase modulators and the better elucidation of AD mechanisms. In this study we successfully generated forebrain neurons from hiPS cells and showed that Aβ production in neuronal cells was detectable and inhibited by some typical secretase inhibitors and modulators. Thus we provide a new platform for AD drug development which might be applied to AD patient-specific iPS cell research. Results Differentiation of forebrain neurons from hiPS cells Recently forebrain neurons were successfully differentiated from mouse embryonic stem (ES) cells [7] [8] [9] and human ES and/or iPS cells [9] [10] [11]. The methods used for differentiation into spinal motor neurons and midbrain dopaminergic neurons required the morphogens retinoic acid (RA)/sonic hedgehog (SHH) and fibroblast growth factor 8 (FGF8)/SHH respectively [11] [12]. On the other hand non-morphogens [10] [11] or Lefty A and Dickkopf homolog 1 (Dkk1) [7] [9] have been used for the induction of hiPS cells into forebrain neurons. Because amyloid plaques are observed in the cerebral cortex from the early stage of AD development [13] stem cells should be differentiated to at least forebrain neurons for assays in AD research. We differentiated forebrain neurons from hiPS 253G4 cells which were generated from human dermal fibroblasts using three reprogramming factors (Oct3/4 Sox2 and Klf4) [14] as described previously (Figure 1A) [12] [15]. When neural stem cells had been induced with Noggin and SB431542 for 17 times we attained cells which were positive for the neuroectodermal marker Nestin (Amount 1B) as previously reported using individual and monkey Ha ATB 346 sido cells [15]. After culturing the cells with morphogen-free moderate for times 17-24 Forkhead container G1 (Foxg1) appearance was induced and Foxg1-positive cells had been observed (Amount 1C D) [11] [15]. We also analyzed whether treatment with cyclopamine an SHH inhibitor elevated the amount of neurons delivering a glutamatergic phenotype as seen in mouse Ha sido cells [8]. The appearance degree of vesicular glutamate transporter 1 (vGlut1) a glutamatergic marker had not been significantly increased with the addition of cyclopamine (last focus 1 μM) from times 17 to 24 (data not really shown). As a result we didn’t add cyclopamine in.