Amyloid precursor proteins, neural differentiation of pluripotent stem cells and its relevance to Alzheimer's disease

A novel antibody targeting sequence 31-35 in amyloid β protein attenuates Alzheimer's disease-related neuronal damage

Amyloid β protein (Aβ) plays a critical role in pathogenesis of Alzheimer's disease (AD). Our previous studies indicated that the sequence 31-35 in Aβ molecule is an effective active center responsible for Aβ neurotoxicity in vivo and in vitro. In the present study, we prepared a novel antibody specifically targeting the sequence 31-35 of amyloid β protein, and investigated the neuroprotection of the anti-Aβ_31-35 antibody against Aβ_1-42 -induced impairments in neuronal viability, spatial memory, and hippocampal synaptic plasticity in rats. The results showed that the anti-Aβ_31-35 antibody almost equally bound to both Aβ_31-35 and Aβ_1-42 , and pretreatment with the antibody dose-dependently prevented Aβ_1-42 -induced cytotoxicity on cultured primary cortical neurons. In behavioral study, intracerebroventricular (i.c.v.) injection of anti-Aβ_31-35 antibody efficiently attenuated Aβ_1-42 -induced impairments in spatial learning and memory of rats. In vivo electrophysiological experiments further indicated that Aβ_1-42 -induced suppression of hippocampal synaptic plasticity was effectively reversed by the antibody. These results demonstrated that the sequence 31-35 of Aβ may be a new therapeutic target, and the anti-Aβ_31-35 antibody could be a novel immunotheraputic approach for the treatment of AD. © 2016 Wiley Periodicals, Inc.

Induced pluripotent stem cells for modeling neurological disorders

Several diseases have been successfully modeled since the development of induced pluripotent stem cell (iPSC) technology in 2006. Since then, methods for increased reprogramming efficiency and cell culture maintenance have been optimized and many protocols for differentiating stem cell lines have been successfully developed, allowing the generation of several cellular subtypes in vitro. Gene editing technologies have also greatly advanced lately, enhancing disease-specific phenotypes by creating isogenic cell lines, allowing mutations to be corrected in affected samples or inserted in control lines. Neurological disorders have benefited the most from iPSC-disease modeling for its capability for generating disease-relevant cell types in vitro from the central nervous system, such as neurons and glial cells, otherwise only available from post-mortem samples. Patient-specific iPSC-derived neural cells can recapitulate the phenotypes of these diseases and therefore, considerably enrich our understanding of pathogenesis, disease mechanism and facilitate the development of drug screening platforms for novel therapeutic targets. Here, we review the accomplishments and the current progress in human neurological disorders by using iPSC modeling for Alzheimer’s disease, Parkinson’s disease, Huntington’s disease, spinal muscular atrophy, amyotrophic lateral sclerosis, duchenne muscular dystrophy, schizophrenia and autism spectrum disorders, which include Timothy syndrome, Fragile X syndrome, Angelman syndrome, Prader-Willi syndrome, Phelan-McDermid, Rett syndrome as well as Nonsyndromic Autism.

Genomic editing tools to model human diseases with isogenic pluripotent stem cells

Patient-specific induced pluripotent stem cells (iPSCs) are considered a versatile resource in the field of biomedicine. As iPSCs are generated on an individual basis, iPSCs may be the optimal cellular material to use for disease modeling, drug discovery, and the development of patient-specific cellular therapies. Recently, to gain an in-depth understanding of human pathologies, patient-specific iPSCs have been used to model human diseases with some iPSC-derived cells recapitulating pathological phenotypes in vitro. However, complex multigenic diseases generally have not resulted in concise conclusions regarding the underlying mechanisms of disease, in large part due to genetic variations between disease-state and control iPSCs. To circumvent this, the use of genomic editing tools to generate perfect isogenic controls is gaining momentum. To date, DNA binding domain-based zinc finger nucleases and transcription activator-like effector nucleases have been utilized to create genetically defined conditions in patient-specific iPSCs, with some examples leading to the successful identification of novel mechanisms of disease. As the feasibility and utility of genomic editing tools in iPSCs improve, along with the introduction of the clustered regularly interspaced short palindromic repeat system, understanding the features and limitations of genomic editing tools and their applications to iPSC technology is critical to expending the field of human disease modeling.