Lee et al. use neural crest precursor cells derived from patient-specific induced pluripotent stem cells to screen a small-molecule library for compounds that correct the cellular phenotype of familial dysautonomia. Patient-specific induced pluripotent stem cells (iPSCs) represent a novel system for modeling human genetic disease and could provide a source of cells for large-scale drug-discovery screens. Here we demonstrate the feasibility of performing a primary screen in neural crest precursors derived from iPSCs that were generated from individuals with familial dysautonomia (FD), a rare, fatal genetic disorder affecting neural crest lineages. We tested 6,912 small-molecule compounds and characterized eight that rescued expression of IKBKAP, the gene responsible for FD. One of the hits, SKF-86466, was found to induce IKBKAP transcription through modulation of intracellular cAMP levels and PKA-dependent CREB phosphorylation. SKF-86466 also rescued IKAP protein expression and the disease-specific loss of autonomic neuronal marker expression. Our data implicate alpha-2 adrenergic receptor activity in regulating IKBKAP expression and demonstrate that small-molecule discovery using an iPSC-based disease model can identify candidate drugs for potential therapeutic intervention.

Duchenne muscular dystrophy (DMD) remains an intractable genetic disease. Althogh there are several animal models of DMD, there is no human cell model that carries patient-specific DYSTROPHIN mutations. Here, we present a human DMD model using human induced pluripotent stem cells (hiPSCs). Our model reveals concordant disease-related phenotypes with patient-dependent variation, which are partially reversed by genetic and pharmacological approaches. Our "chemical-compound-based" strategy successfully directs hiPSCs into expandable myoblasts, which exhibit a myogenic transcriptional program, forming striated contractile myofibers and participating in muscle regeneration in vivo. DMD-hiPSC-derived myoblasts show disease-related phenotypes with patient-to-patient variability, including aberrant expression of inflammation or immune-response genes and collagens, increased BMP/TGFβ signaling, and reduced fusion competence. Furthermore, by genetic correction and pharmacological "dual-SMAD" inhibition, the DMD-hiPSC-derived myoblasts and genetically corrected isogenic myoblasts form "rescued" multi-nucleated myotubes. In conclusion, our findings demonstrate the feasibility of establishing a human "DMD-in-a-dish" model using hiPSC-based disease modeling.

Glioma tumor suppressor candidate region gene 2 (GLTSCR2/PICT-1) is localized within the well-known 1.4-Mb tumor suppressive region of chromosome 19q, which is frequently altered in various human tumors, including diffuse gliomas. Aside from its localization on the chromosome, several lines of evidence, such as PTEN phosphorylation, support that GLTSCR2 partakes in the suppression of tumor growth and development. However, much remains unknown about the molecular mechanisms of the tumor suppressive activity of GLTSCR2. The purpose of this study was to investigate the molecular mechanisms of GLTSCR2 in cell death pathways in association with its binding partner PTEN. In this work, we show that GLTSCR2 is a nucleus-localized protein with a discrete globular expression pattern. In addition to phosphorylating PTEN, GLTSCR2 induces caspase-independent PTEN-modulated apoptotic cell death when overexpressed. However, the cytotoxic activity of GLTSCR2 is independent of its ability to phosphorylate PTEN, suggesting that the GLTSCR2-induced cell death pathway is divergent from PTEN-induced death pathways. Our results suggest that the induction of PTEN-modulated apoptosis is one of the putative mechanisms of tumor suppressive activity by GLTSCR2.

Patients with recent pandemic coronavirus disease 19 (COVID-19) complain of neurological abnormalities in sensory functions such as smell and taste in the early stages of infection. Determining the cellular and molecular mechanism of sensory impairment is critical to understand the pathogenesis of clinical manifestations, as well as in setting therapeutic targets for sequelae and recurrence. The absence of studies utilizing proper models of human peripheral nerve hampers an understanding of COVID-19 pathogenesis. Here, we report that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) directly infects human peripheral sensory neurons, leading to molecular pathogenesis for chemosensory impairments. An in vitro system utilizing human embryonic stem cell (hESC)-derived peripheral neurons was used to model the cellular and molecular pathologies responsible for symptoms that most COVID-19 patients experience early in infection or may develop as sequelae. Peripheral neurons differentiated from hESCs expressed viral entry factor ACE2, and were directly infected with SARS-CoV-2 via ACE2. Human peripheral neurons infected with SARS-CoV-2 exhibited impaired molecular features of chemosensory function associated with abnormalities in sensory neurons of the olfactory or gustatory organs. Our results provide new insights into the pathogenesis of chemosensory dysfunction in patients with COVID-19.