Gustavo Mostoslavsky

Common variable immunodeficiency (CVID) is the most prevalent symptomatic primary antibody deficiency. For unclear reasons, inflammatory complications, like gastrointestinal (GI) disease, occur in ~50% of CVID cases, worsening morbidity and mortality. NFKB1 variants are among the most frequent genetic variants in CVID. While effect of NFKB1 variants is not well understood, we previously found frameshift heterozygous NFKB1 variants to increase cytokines, monocytes, and inflammatory complications in CVID. In this report, we used induced pluripotent stem cell–derived (iPSC-derived) monocytes (iMONOs) with CRISPR/Cas9-mediated gene editing to study a heterozygous NFKB1 frameshift found in a patient with CVID with severe GI disease. The heterozygous NFKB1 variant similarly reduced NFKB1 protein in CVID patient– and healthy donor–derived iMONOs, but elevated LPS-induced IL-1β release and expression of inflammatory genes, including IL1B , IL6 , TNF , and neutrophil chemoattractants, only in CVID patient iMONOs. CVID patient iMONOs also had elevations of IL-12, CCL4, and CCL12 unaffected by presence or absence of the NFKB1 variant. TNF antagonism improved the patient’s GI disease, diminishing neutrophilic gastritis, circulating neutrophils, and the neutrophil chemoattractant CXCL1 in the blood. While the biology remains complex, our approach found heterozygous NFKB1 variant–induced inflammatory changes intensified in CVID iMONOs, corresponding with clinical response to TNF antagonism.

Gastrointestinal (GI) dysfunction, characterized by severe diarrhea and dehydration, is a central contributor to morbidity and mortality in filovirus disease in patients, yet the role of the epithelium in this clinical outcome remains poorly defined. Here, we employ induced pluripotent stem cell (iPSC)-derived human intestinal (HIOs) and colonic organoids (HCOs) to model Ebola virus (EBOV) and Marburg virus (MARV) infection. These organoids are permissive to filovirus infection and support viral replication. Bulk RNA sequencing revealed distinct intestinal and colonic epithelial responses, including apical and junctional disruption and a delayed virus-specific induction of interferon-stimulated genes. Moreover, infection impaired adenylate cyclase signaling and CFTR-mediated ion transport, providing mechanistic insight into virus-induced secretory diarrhea. This platform recapitulates key features of human GI pathology in filoviral disease and serves as a powerful system to dissect host-pathogen interactions and identify therapeutic targets.

Cystic fibrosis is a monogenic lung disease caused by dysfunction of the cystic fibrosis transmembrane conductance regulator anion channel, resulting in significant morbidity and mortality. The progress in elucidating the role of CFTR using established animal and cell-based models led to the recent discovery of effective modulators for most individuals with CF. However, a subset of individuals with CF do not respond to these modulators and there is an urgent need to develop novel therapeutic strategies. In this study, we generate a panel of airway epithelial cells using induced pluripotent stem cells from individuals with common or rare CFTR variants representative of three distinct classes of CFTR dysfunction. To measure CFTR function we adapt two established in vitro assays for use in induced pluripotent stem cell-derived airway cells. In both a 3-D spheroid assay using forskolin-induced swelling as well as planar cultures composed of polarized mucociliary airway epithelial cells, we detect genotype-specific differences in CFTR baseline function and response to CFTR modulators. These results demonstrate the potential of the human induced pluripotent stem cell platform as a research tool to study CF and in particular accelerate therapeutic development for CF caused by rare variants.

Summary: The most common subtype of genetic prion disease is caused by the E200K mutation of the prion protein. We have obtained samples from 22 members of a multi-generational Israeli family harboring this mutation, and generated a library of induced pluripotent stem cells (iPSCs) representing nine carriers and four non-carriers. Whole-exome sequencing was performed on all individuals. A comparison of neurons derived from E200K iPSCs to those from non-carriers revealed the presence of several disease-relevant phenotypes. Neurons from E200K carriers were found to contain thioflavin S-positive accumulations of PrP in their cell bodies. In addition, these neurons displayed disruptions of NMDA receptor/PSD95 co-localization at postsynaptic sites. Our study shows that iPSC-derived neurons, which express physiologically relevant levels of mutant PrP in a human neuronal context, can model certain aspects of human prion disease, offering a powerful platform for investigating pathological mechanisms and testing potential therapeutics.