技术资料

Alzheimer's disease (AD) is among the most prevalent forms of dementia affecting the aging population,and pharmacological therapies to date have not been successful in preventing disease progression. Future therapeutic efforts may benefit from the development of models that enable basic investigation of early disease pathology. In particular,disease-relevant models based on human pluripotent stem cells (hPSCs) may be promising approaches to assess the impact of neurotoxic agents in AD on specific neuronal populations and thereby facilitate the development of novel interventions to avert early disease mechanisms. We implemented an efficient paradigm to convert hPSCs into enriched populations of cortical glutamatergic neurons emerging from dorsal forebrain neural progenitors,aided by modulating Sonic hedgehog (Shh) signaling. Since AD is generally known to be toxic to glutamatergic circuits,we exposed glutamatergic neurons derived from hESCs to an oligomeric pre-fibrillar forms of Aβ known as globulomers"� View Publication

Human induced pluripotent stem cells (iPSC) can be used to understand the pathological mechanisms of human disease. These cells are a promising source for cell-replacement therapy. However,such studies require genetically defined conditions. Such genetic manipulations can be performed using the novel Transcription Activator-Like Effector Nucleases (TALENs),which generate site-specific double-strand DNA breaks (DSBs) with high efficiency and precision. Combining the TALEN and iPSC methods,we developed two iPS cell lines by generating the point mutation A5768G in the SCN1A gene,which encodes the voltage-gated sodium channel Nav1.1 α subunit. The engineered iPSC maintained pluripotency and successfully differentiated into neurons with normal functional characteristics. The two cell lines differ exclusively at the epilepsy-susceptibility variant. The ability to robustly introduce disease-causing point mutations in normal hiPS cell lines can be used to generate a human cell model for studying epileptic mechanisms and for drug screening. View Publication

In Huntington's disease (HD),whether transneuronal spreading of mutant huntingtin (mHTT) occurs and its contribution to non-cell autonomous damage in brain networks is largely unknown. We found mHTT spreading in three different neural network models: human neurons integrated in the neural network of organotypic brain slices of HD mouse model,an ex vivo corticostriatal slice model and the corticostriatal pathway in vivo. Transneuronal propagation of mHTT was blocked by two different botulinum neurotoxins,each known for specifically inactivating a single critical component of the synaptic vesicle fusion machinery. Moreover,healthy human neurons in HD mouse model brain slices displayed non-cell autonomous changes in morphological integrity that were more pronounced when these neurons bore mHTT aggregates. Altogether,our findings suggest that transneuronal propagation of mHTT might be an important and underestimated contributor to the pathophysiology of HD. View Publication

Down's syndrome (DS),caused by trisomy of human chromosome 21,is the most common genetic cause of intellectual disability. Here we use induced pluripotent stem cells (iPSCs) derived from DS patients to identify a role for astrocytes in DS pathogenesis. DS astroglia exhibit higher levels of reactive oxygen species and lower levels of synaptogenic molecules. Astrocyte-conditioned medium collected from DS astroglia causes toxicity to neurons,and fails to promote neuronal ion channel maturation and synapse formation. Transplantation studies show that DS astroglia do not promote neurogenesis of endogenous neural stem cells in vivo. We also observed abnormal gene expression profiles from DS astroglia. Finally,we show that the FDA-approved antibiotic drug,minocycline,partially corrects the pathological phenotypes of DS astroglia by specifically modulating the expression of S100B,GFAP,inducible nitric oxide synthase,and thrombospondins 1 and 2 in DS astroglia. Our studies shed light on the pathogenesis and possible treatment of DS by targeting astrocytes with a clinically available drug. View Publication