Chattopadhyay, R. | Search bioRxiv

bioRxiv2020

Adult Stem Cell-derived Complete Lung Organoid Models Emulate Lung Disease in COVID-19

SARS-CoV-2, the virus responsible for COVID-19, causes widespread damage in the lungs in the setting of an overzealous immune response whose origin remains unclear. We present a scalable, propagable, personalized, cost-effective adult stem cell-derived human lung organoid model that is complete with both proximal and distal airway epithelia. Monolayers derived from adult lung organoids (ALOs), primary airway cells, or hiPSC-derived alveolar type-II (AT2) pneumocytes were infected with SARS-CoV-2 to create in vitro lung models of COVID-19. Infected ALO-monolayers best recapitulated the transcriptomic signatures in diverse cohorts of COVID-19 patient-derived respiratory samples. The airway (proximal) cells were critical for sustained viral infection, whereas distal alveolar differentiation (AT2[->]AT1) was critical for mounting the overzealous host immune response in fatal disease; ALO monolayers with well-mixed proximodistal airway components recapitulated both. Findings validate a human lung model of COVID-19, which can be immediately utilized to investigate COVID-19 pathogenesis and vet new therapies and vaccines. GRAPHIC ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=176 SRC="FIGDIR/small/344002v4_ufig1.gif" ALT="Figure 1"> View larger version (52K): org.highwire.dtl.DTLVardef@1d1507aorg.highwire.dtl.DTLVardef@faa17forg.highwire.dtl.DTLVardef@80ceb1org.highwire.dtl.DTLVardef@81d61c_HPS_FORMAT_FIGEXP M_FIG C_FIG HIGHLIGHTSO_LIHuman lung organoids with mixed proximodistal epithelia are created C_LIO_LIProximal airway cells are critical for viral infectivity C_LIO_LIDistal alveolar cells are important for emulating host response C_LIO_LIBoth are required for the overzealous response in severe COVID-19 C_LI IN BRIEFAn integrated stem cell-based disease modeling and computational approach demonstrate how both proximal airway epithelium is critical for SARS-CoV-2 infectivity, but distal differentiation of alveolar pneumocytes is critical for simulating the overzealous host response in fatal COVID-19.

cell biology↗

bioRxiv2018

Dysregulation of the engulfment pathway in the gut fuels Inflammatory Bowel Disease

BACKGROUND & AIMSLuminal dysbiosis is ubiquitous in inflammatory bowel disease (IBD), but how the microbes trigger pro-inflammatory cascades in the epithelial and phagocytic cells remains unknown. Here we investigated the role of the microbial sensor ELMO1 (Engulfment and Cell Motility Protein-1) in sensing and responding to IBD-associated microbes in the gut epithelium and in macrophages.\n\nMETHODSA stem cell-based technique is used to grow enteroids from WT and ELMO1-/-mice and from colonic biopsies of patients with IBD and subsequently differentiate them into enteroid-derived monolayers (EDMs) that mimic the gut epithelium/Gut in a dish. EDMs infected with IBD-associated invasive E. coli-LF82 were analyzed for bacterial internalization, cytokine production and monocyte-recruitment when co-cultured with monocytes.\n\nRESULTSExpression of ELMO1 is elevated in the colonic epithelium and in the inflammatory infiltrates within the lamina propria in IBD, higher expression correlated with elevated expression of pro-inflammatory cytokines, MCP-1 and TNF-. ELMO1-/-murine EDMs displayed a significant reduction of bacterial internalization through epithelial tight junctions and in MCP-1 production compared to WT mice. MCP-1 that is released from the epithelium recruited monocytes. Once recruited, macrophages required ELMO1 to engulf the bacteria and propagate a robust pro-inflammatory cytokine storm (TNF-).\n\nCONCLUSIONSELMO1 couples microbial-sensing to inflammation in both phagocytic and non-phagocytic host cells; it is required for the production of MCP-1 in the epithelium and TNF- in macrophages. Findings raise the possibility that upregulation of epithelial ELMO1 and the epithelial ELMO1[->]MCP-1 axis may serve as an early biomarker and therapeutic target, respectively, in IBD and other disorders of inflammation.

cell biology↗