Human airway lineages derived from pluripotent stem cells reveal the epithelial responses to SARS-CoV-2 infection (preprint)

There is an urgent need to understand how SARS-CoV-2 infects the airway epithelium and in a subset of individuals leads to severe illness or death. Induced pluripotent stem cells (iPSCs) provide a near limitless supply of human cells that can be differentiated into cell types of interest, including airway epithelium, for disease modeling. We present a human iPSC-derived airway epithelial platform, composed of the major airway epithelial cell types, that is permissive to SARS-CoV-2 infection. Subsets of iPSC-airway cells express the SARS-CoV-2 entry factors ACE2 and TMPRSS2. Multiciliated cells are the primary initial target of SARS-CoV-2 infection. Upon infection with SARS-CoV-2, iPSC-airway cells generate robust interferon and inflammatory responses and treatment with remdesivir or camostat methylate causes a decrease in viral propagation and entry, respectively. In conclusion, iPSC-derived airway cells provide a physiologically relevant in vitro model system to interrogate the pathogenesis of, and develop treatment strategies for, COVID-19 pneumonia.

Human Pluripotent Stem Cell Derived Intestinal Organoids Model SARS-CoV-2 Infection Revealing a Common Epithelial Inflammatory Response (preprint)

SARS-CoV-2 infection leading to COVID-19 usually results in respiratory disease, but extrapulmonary manifestations are of major clinical interest. Intestinal symptoms of COVID-19 are present in a significant number of patients, and include nausea, diarrhea, and viral RNA shedding in feces. Human induced pluripotent stem cell (iPSC) derived intestinal organoids (HIOs) represent an inexhaustible cellular resource that could serve as a valuable tool to study SARS-CoV-2 as well as other enteric viruses that infect the intestinal epithelium. Here, we report that SARS-CoV-2 productively infects both proximally and distally patterned HIOs, leading to the release of infectious viral particles while stimulating a robust transcriptomic response, including a significant upregulation of interferon-related genes that appeared to be conserved across multiple epithelial cell types. These findings illuminate a potential inflammatory epithelial-specific signature that may contribute to both the multisystemic nature of COVID-19 as well as its highly variable clinical presentation.Funding: This work was supported by Evergrande MassCPR and Fast Grants awards to EM. AM is supported by the Kilachand Multicellular Design Program at Boston University. GM is supported by NIH Grants N0175N92020C00005 and 1R01DA051889-01.Conflict of Interest: The authors declare no competing interests.

SARS-CoV-2 Infection of Pluripotent Stem Cell-derived Human Lung Alveolar Type 2 Cells Elicits a Rapid Epithelial-Intrinsic Inflammatory Response (preprint)

ABSTRACTThe most severe and fatal infections with SARS-CoV-2 result in the acute respiratory distress syndrome, a clinical phenotype of coronavirus disease 2019 (COVID-19) that is associated with virions targeting the epithelium of the distal lung, particularly the facultative progenitors of this tissue, alveolar epithelial type 2 cells (AT2s). Little is known about the initial responses of human lung alveoli to SARS-CoV-2 infection due in part to inability to access these cells from patients, particularly at early stages of disease. Here we present an in vitro human model that simulates the initial apical infection of the distal lung epithelium with SARS-CoV-2, using AT2s that have been adapted to air-liquid interface culture after their derivation from induced pluripotent stem cells (iAT2s). We find that SARS-CoV-2 induces a rapid global transcriptomic change in infected iAT2s characterized by a shift to an inflammatory phenotype predominated by the secretion of cytokines encoded by NF-kB target genes, delayed epithelial interferon responses, and rapid loss of the mature lung alveolar epithelial program. Over time, infected iAT2s exhibit cellular toxicity that can result in the death of these key alveolar facultative progenitors, as is observed in vivo in COVID-19 lung autopsies. Importantly, drug testing using iAT2s confirmed the efficacy of TMPRSS2 protease inhibition, validating putative mechanisms used for viral entry in human alveolar cells. Our model system reveals the cell-intrinsic responses of a key lung target cell to infection, providing a platform for further drug development and facilitating a deeper understanding of COVID-19 pathogenesis.Competing Interest StatementThe authors have declared no competing interest.View Full Text