Large structural variants in KOLF2.1J are unlikely to compromise neurological disease modelling.

Gracia-Diaz and colleagues analysed high-density DNA microarray and whole genome sequencing (WGS) data from the KOLF2.1J 'reference' human induced pluripotent stem cell (hiPSC) line, and report the presence of five high-confidence heterozygous copy number variants (CNVs) at least 100kbp in length. Since three of these CNVs span coding genes, some of which have been associated with neurodevelopmental disease, the authors raise the concern that these CNVs may compromise the utility of KOLF2.

Generation of four gene-edited human induced pluripotent stem cell lines with mutations in the ATM gene to model Ataxia-Telangiectasia.

Ataxia-Telangiectasia (A-T) is an autosomal recessive multi-system disorder caused by mutations in the ataxia-telangiectasia mutated (ATM) gene, resulting, among other symptoms, in neurological dysfunction. ATM is known to be a master controller of signal transduction for DNA damage response, with additional functions that are poorly understood. CRISPR/Cas9 technology was used to introduce biallelic mutations at selected sites of the ATM gene in human induced pluripotent stem cells (hiPSCs).

Human iPSC-derived microglia sense and dampen hyperexcitability of cortical neurons carrying the epilepsy-associated SCN2A-L1342P mutation.

Neuronal hyperexcitability is a hallmark of seizures. It has been recently shown in rodent models of seizures that microglia, the brain's resident immune cells, can respond to and modulate neuronal excitability. However, how human microglia interacts with human neurons to regulate hyperexcitability mediated by epilepsy-causing genetic mutation found in human patients remains unknown.

Generation of glucocorticoid-producing cells derived from human pluripotent stem cells.

Adrenal insufficiency is a life-threatening condition resulting from the inability to produce adrenal hormones in a dose- and time-dependent manner. Establishing a cell-based therapy would provide a physiologically responsive approach for the treatment of this condition. We report the generation of large numbers of human-induced steroidogenic cells (hiSCs) from human pluripotent stem cells (hPSCs).

Africa-specific human genetic variation near CHD1L associates with HIV-1 load.

HIV-1 remains a global health crisis, highlighting the need to identify new targets for therapies. Here, given the disproportionate HIV-1 burden and marked human genome diversity in Africa, we assessed the genetic determinants of control of set-point viral load in 3,879 people of African ancestries living with HIV-1 participating in the international collaboration for the genomics of HIV. We identify a previously undescribed association signal on chromosome 1 where the peak variant associates with an approximately 0.

Expression of ALS-PFN1 impairs vesicular degradation in iPSC-derived microglia.

Microglia play a pivotal role in neurodegenerative disease pathogenesis, but the mechanisms underlying microglia dysfunction and toxicity remain to be fully elucidated. To investigate the effect of neurodegenerative disease-linked genes on the intrinsic properties of microglia, we studied microglia-like cells derived from human induced pluripotent stem cells (iPSCs), termed iMGs, harboring mutations in profilin-1 (PFN1) that are causative for amyotrophic lateral sclerosis (ALS). ALS-PFN1 iMGs exhibited lipid dysmetabolism and deficits in phagocytosis, a critical microglia function.

A reference human induced pluripotent stem cell line for large-scale collaborative studies.

Human induced pluripotent stem cell (iPSC) lines are a powerful tool for studying development and disease, but the considerable phenotypic variation between lines makes it challenging to replicate key findings and integrate data across research groups. To address this issue, we sub-cloned candidate human iPSC lines and deeply characterized their genetic properties using whole genome sequencing, their genomic stability upon CRISPR-Cas9-based gene editing, and their phenotypic properties including differentiation to commonly used cell types. These studies identified KOLF2.

Hyperexcitability and Pharmacological Responsiveness of Cortical Neurons Derived from Human iPSCs Carrying Epilepsy-Associated Sodium Channel Nav1.2-L1342P Genetic Variant.

With the wide adoption of genomic sequencing in children having seizures, an increasing number of genetic variants have been revealed as genetic causes of epilepsy. Voltage-gated sodium channel Nav1.2, encoded by gene , is predominantly expressed in the pyramidal excitatory neurons and supports action potential (AP) firing.

Severe deficiency of the voltage-gated sodium channel Na1.2 elevates neuronal excitability in adult mice.

Scn2a encodes the voltage-gated sodium channel Na1.2, a main mediator of neuronal action potential firing. The current paradigm suggests that Na1.

A systematic CRISPR screen defines mutational mechanisms underpinning signatures caused by replication errors and endogenous DNA damage.

Mutational signatures are imprints of pathophysiological processes arising through tumorigenesis. We generated isogenic CRISPR-Cas9 knockouts (Δ) of 43 genes in human induced pluripotent stem cells, cultured them in the absence of added DNA damage, and performed whole-genome sequencing of 173 subclones. Δ Δ Δ Δ Δ Δ Δ Δ and Δ produced marked mutational signatures indicative of being critical mitigators of endogenous DNA modifications.

Interactions between ALS-linked FUS and nucleoporins are associated with defects in the nucleocytoplasmic transport pathway.

Nucleocytoplasmic transport (NCT) decline occurs with aging and neurodegeneration. Here, we investigated the NCT pathway in models of amyotrophic lateral sclerosis-fused in sarcoma (ALS-FUS). Expression of ALS-FUS led to a reduction in NCT and nucleoporin (Nup) density within the nuclear membrane of human neurons.

A resource of targeted mutant mouse lines for 5,061 genes.

The International Mouse Phenotyping Consortium reports the generation of new mouse mutant strains for over 5,000 genes, including 2,850 novel null, 2,987 novel conditional- ready, and 4,433 novel reporter alleles.

Tackling neurodegenerative diseases with genomic engineering: A new stem cell initiative from the NIH.

The iPSC Neurodegenerative Disease Initiative (iNDI) is the largest-ever iPSC genome engineering project. iNDI will model more than 100 mutations associated with Alzheimer's disease and related dementias (ADRD) in isogenic iPSC lines. Resulting cell lines and phenotypic datasets will be broadly shared.

Generation and basic characterization of a gene-trap knockout mouse model of Scn2a with a substantial reduction of voltage-gated sodium channel Na 1.2 expression.

Large-scale genetic studies revealed SCN2A as one of the most frequently mutated genes in patients with neurodevelopmental disorders. SCN2A encodes for the voltage-gated sodium channel isoform 1.2 (Na 1.

A Novel Chemically Differentiated Mouse Embryonic Stem Cell-Based Model to Study Liver Stages of Plasmodium berghei.

Asymptomatic and obligatory liver stage (LS) infection of Plasmodium parasites presents an attractive target for antimalarial vaccine and drug development. Lack of robust cellular models to study LS infection has hindered the discovery and validation of host genes essential for intrahepatic parasite development. Here, we present a chemically differentiated mouse embryonic stem cell (ESC)-based LS model, which supports complete development of Plasmodium berghei exoerythrocytic forms (EEFs) and can be used to define new host-parasite interactions.

Loss of IL-10 signaling in macrophages limits bacterial killing driven by prostaglandin E2.

Loss of IL-10 signaling in macrophages (Mφs) leads to inflammatory bowel disease (IBD). Induced pluripotent stem cells (iPSCs) were generated from an infantile-onset IBD patient lacking a functional IL10RB gene. Mφs differentiated from IL-10RB-/- iPSCs lacked IL-10RB mRNA expression, were unable to phosphorylate STAT3, and failed to reduce LPS induced inflammatory cytokines in the presence of exogenous IL-10.

Improving homology-directed repair efficiency in human stem cells.

The generation of induced pluripotent stem cell models of human disease requires efficient modification of one or both alleles depending on dominant or recessive inheritance of the disease. To faithfully recapitulate many disease variants, the introduction of a single base change is required. The introduction of additional silent mutations designed to prevent re-cutting of the modified allele by Cas9 is not an optimal strategy, particularly for non-coding variants.

Corrigendum: High-throughput discovery of novel developmental phenotypes.

This corrects the article DOI: 10.1038/nature19356.