Potentially pathogenic alterations have been identified in individuals with autism spectrum disorders (ASDs) within a variety of key neurodevelopment genes. While this hints at a common ASD molecular etiology, gaps persist in our understanding of the neurodevelopmental mechanisms impacted by genetic variants enriched in ASD patients. Induced pluripotent stem cells (iPSCs) can model neurodevelopment in vitro, permitting the characterization of pathogenic mechanisms that manifest during corticogenesis. Taking this approach, we examined the transcriptional differences between iPSC-derived cortical neurons from patients with idiopathic ASD and unaffected controls over a 135-day course of neuronal differentiation. Our data show ASD-specific misregulation of genes involved in neuronal differentiation, axon guidance, cell migration, DNA and RNA metabolism, and neural region patterning. Furthermore, functional analysis revealed defects in neuronal migration and electrophysiological activity, providing compelling support for the transcriptome analysis data. This study reveals important and functionally validated insights into common processes altered in early neuronal development and corticogenesis and may contribute to ASD pathogenesis.

What pathways specify retinal ganglion cell (RGC) fate in the developing retina? Here we report on mechanisms by which a molecular pathway involving Sox4/Sox11 is required for RGC differentiation and for optic nerve formation in mice , and is sufficient to differentiate human induced pluripotent stem cells into electrophysiologically active RGCs. These data place Sox4 downstream of RE1 silencing transcription factor in regulating RGC fate, and further describe a newly identified, Sox4-regulated site for post-translational modification with small ubiquitin-related modifier (SUMOylation) in Sox11, which suppresses Sox11's nuclear localization and its ability to promote RGC differentiation, providing a mechanism for the SoxC familial compensation observed here and elsewhere in the nervous system. These data define novel regulatory mechanisms for this SoxC molecular network, and suggest pro-RGC molecular approaches for cell replacement-based therapies for glaucoma and other optic neuropathies. Glaucoma is the most common cause of blindness worldwide and, along with other optic neuropathies, is characterized by loss of retinal ganglion cells (RGCs). Unfortunately, vision and RGC loss are irreversible, and lead to bilateral blindness in ∼14% of all diagnosed patients. Differentiated and transplanted RGC-like cells derived from stem cells have the potential to replace neurons that have already been lost and thereby to restore visual function. These data uncover new mechanisms of retinal progenitor cell (RPC)-to-RGC and human stem cell-to-RGC fate specification, and take a significant step toward understanding neuronal and retinal development and ultimately cell-transplant therapy.

Induced pluripotent stem cells (iPSCs) hold tremendous potential both as a biological tool to uncover the pathophysiology of disease by creating relevant cell models and as a source of stem cells for cell-based therapeutic applications. Typically, iPSCs have been derived by the transgenic overexpression of transcription factors associated with progenitor cell or stem cell function in fibroblasts derived from skin biopsies. However, the need for skin punch biopsies to derive fibroblasts for reprogramming can present a barrier to study participation among certain populations of individuals, including children with autism spectrum disorders (ASDs). In addition, the acquisition of skin punch biopsies in non-clinic settings presents a challenge. One potential mechanism to avoid these limitations would be the use of peripheral blood mononuclear cells (PBMCs) as the source of the cells for reprogramming. In this article we describe the derivation of iPSC lines from PBMCs isolated from the whole blood of autistic children, and their subsequent differentiation in GABAergic neurons.