Project description:Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent of the global COVID-19 pandemic and the lack of therapeutics hinders pandemic control. Although lung disease is the primary clinical outcome in COVID-19 patients, how SARS-CoV-2 induces tissue pathology in the lung remains elusive. Here we describe a high-throughput-based platform to generate tens of thousands of self-organizing, nearly identical, and genetically matched human lung buds derived from human pluripotent stem cells (hPSCs) cultured on confined geometries on micropattern chips. Strikingly, in vitro-derived human lung buds resemble fetal human lung tissue and display in vivo-like proximo-distal coordination of alveolar and airway tissue differentiation whose 3D epithelial self-organization is directed by the levels of KGF. Single-cell transcriptomics unveiled the cell identities and ontogeny of airway and alveolar tissue and the specification of WNThi cycling alveolar stem cells from alveolar progenitors. These synthetic human lung buds are susceptible to SARS-CoV-2 infection and can be used to track cell type-dependent susceptibilities to infection, intercellular transmission and cytopathology in airway and alveolar tissue in individual synthetic lung buds. We detected an increased susceptibility to infection in alveolar cells and identified cycling alveolar stem cells as targets of SARS-CoV-2. We used this platform to test neutralizing antibodies isolated from convalescent plasma that efficiently blocked SARS-CoV-2 infection and intercellular transmission. Our platform offers unlimited, rapid and scalable access to disease-relevant lung tissue that recapitulate human lung development and can be used to track SARS-CoV-2 infection and identify pre-clinical candidate therapeutics for COVID-19.
Project description:Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent of the global COVID-19 pandemic and the lack of therapeutics hinders pandemic control1-2. Although lung disease is the primary clinical outcome in COVID-19 patients1-3, how SARS-CoV-2 induces tissue pathology in the lung remains elusive. Here we describe a high-throughput platform to generate tens of thousands of self-organizing, nearly identical, and genetically matched human lung buds derived from human pluripotent stem cells (hPSCs) cultured on micropatterned substrates. Strikingly, in vitro-derived human lung buds resemble fetal human lung tissue and display in vivo-like proximo-distal coordination of alveolar and airway tissue differentiation whose 3D epithelial self-organization is directed by the levels of KGF. Single-cell transcriptomics unveiled the cellular identities of airway and alveolar tissue and the differentiation of WNThi cycling alveolar stem cells, a human-specific lung cell type4. These synthetic human lung buds are susceptible to infection by SARS-CoV-2 and endemic coronaviruses and can be used to track cell type-dependent susceptibilities to infection, intercellular transmission and cytopathology in airway and alveolar tissue in individual lung buds. Interestingly, we detected an increased susceptibility to infection in alveolar cells and identified cycling alveolar stem cells as targets of SARS-CoV-2. We used this platform to test neutralizing antibodies isolated from convalescent plasma that efficiently blocked SARS-CoV-2 infection and intercellular transmission. Our platform offers unlimited, rapid and scalable access to disease-relevant lung tissue that recapitulate key hallmarks of human lung development and can be used to track SARS-CoV-2 infection and identify candidate therapeutics for COVID-19.
Project description:Polycomb group (PcG) proteins play a pivotal role in epigenetically silencing development-related genes, restricting their expression to appropriate tissues. However, in some instances PcG target genes must also be dynamically regulated in response to developmental signals encountered during morphogenesis. Here we examine the role of PcG factors in early forelimb bud patterning, a process that relies on various morphogenetic signals. Depletion of Ring1 proteins, which are essential components of Polycomb repressive complex-1 (PRC1), led to dramatic deficiencies in forelimb formation and proximal-distal regionalization. Gene expression analysis identified Meis2 and Meis1 as critical PRC1 targets genes in early distal specification, with PcG proteins counteracting retinoic acid (RA) signaling to control their expression. Importantly, in this system, PcG factors appear to function by adjusting the threshold for RA signaling, revealing an unexpected role of polycomb proteins in dynamic gene regulation during development. [Affymetrix] Mouse E10.5 forelimb buds of Ring1A-KO, Ring1A/B-dKO and RA-treated wild type were used for RNA extraction and hybridization on Affymetrix microarrays. [Agilent] ChIP analysis of mouse E10.5 whole forelimb buds against anti-H3K27me3 antibody.
Project description:Here, we demonstrate a generalized method for organ bud formation from diverse tissues by combining pluripotent stem cell-derived tissue-specific progenitors or relevant tissue samples with endothelial cells and mesenchymal stem cells (MSCs). The MSCs initiated condensation within these heterotypic cell mixtures, which was dependent upon substrate matrix stiffness. Defining optimal mechanical properties promoted formation of 3D, transplantable organ buds from tissues including kidney, pancreas, intestine, heart, lung, and brain. Transplanted pancreatic and renal buds were rapidly vascularized and self-organized into functional, tissue-specific structures. These findings provide a general platform for harnessing mechanical properties to generate vascularized, complex organ buds with broad applications for regenerative medicine.
Project description:The proximal-distal patterning program determines unique structural and functional properties of proximal and distal airways in the adult lung. Based on the knowledge that remod-eling of distal airways is the major pathologic feature of chronic obstructive pulmonary disease (COPD), and that small airway epithelium (SAE), which covers distal airways, is the primary site of the initial smoking-induced changes relevant to COPD pathogenesis, we hypothesized that in COPD smokers, the SAE transcriptome loses its region-specific biologic identity and takes on the transcriptional pattern of the proximal airways. By analyzing human airway epithelium col-lected by bronchoscopic brushings from proximal and distal airways of healthy smokers, proxi-mal and distal airway epithelial transcriptome signatures were identified. Dramatic smoking-dependent suppression of distal signature paralleled by acquisition of the proximal airway epithe-lial phenotype was found in the SAE of COPD smokers. Distal-proximal re-patterning observed in the SAE of smokers in vivo was reproduced in vitro by stimulating SAE basal cells (BC), the stem/progenitor cells of the SAE, with EGF, a growth factor up-regulated in airway epithelium by smoking. Together, this study identifies distal-proximal SAE re-patterning as a characteristic feature of small airway disordering in COPD smokers potentially driven by EGF/EGFR-mediated reprogramming of SAE BC stem/progenitor cells.
Project description:Dissecting the dynamics of signaling events in the BMP,WNT and NODAL cascade during self-organized fate patterning in human gastruloids
Project description:Despite the importance of Hox genes in patterning the mouse embryo, few target genes of the Hox transcription factors have been identified. To search for HoxD targets we contrasted gene expression profiles in the presence and absence of the HoxD genes in two tissues where these genes are important in embryonic patterning-the genital bud and the distal domain of the limb. The Del9 mutant, in which all nine HoxD genes are absent, shows perturbed digit and genital morphogenesis. Therefore we used Affymetrix GeneChip arrays to compare gene expression in forelimb autopods and genital buds from wild type and homozygous Del9 E12.5 embryos.
Project description:Here, we demonstrate a generalized method for organ bud formation from diverse tissues by combining pluripotent stem cell-derived tissue-specific progenitors or relevant tissue samples with endothelial cells and mesenchymal stem cells (MSCs). The MSCs initiated condensation within these heterotypic cell mixtures, which was dependent upon substrate matrix stiffness. Defining optimal mechanical properties promoted formation of 3D, transplantable organ buds from tissues including kidney, pancreas, intestine, heart, lung, and brain. Transplanted pancreatic and renal buds were rapidly vascularized and self-organized into functional, tissue-specific structures. These findings provide a general platform for harnessing mechanical properties to generate vascularized, complex organ buds with broad applications for regenerative medicine. Gene expression profiles of development-related gene expression in kidney bud transplants and murine kidneys.