03178nas a2200589   4500000000100000000000100001008004100002260001200043653002100055653002000076653001500096100002400111700002000135700001800155700001500173700002100188700002000209700001800229700002500247700002600272700001400298700001700312700001700329700002200346700002300368700001800391700001700409700002100426700002100447700001700468700001900485700002100504700002200525700002300547700002400570700002000594700002100614700002600635700001800661700001900679700001900698700002100717700002300738700002000761700001800781245008600799856005400885300001200939490000800951520161500959022001402574       2020                            d  c2020-1210aAdult Stem Cells10aInfluenza virus10aSARS-CoV-21 aAmeen A. Salahudeen1 aShannon S. Choi1 aArjun Rustagi1 aJunjie Zhu1 aVincent van Unen1 aSean M. de la O1 aRyan A. Flynn1 aMar Margalef-Català1 aAntónio J. M. Santos1 aJihang Ju1 aArpit Batish1 aTatsuya Usui1 aGrace X. Y. Zheng1 aCaitlin E. Edwards1 aLisa E. Wagar1 aVincent Luca1 aBenedict Anchang1 aMonica Nagendran1 aKhanh Nguyen1 aDaniel J. Hart1 aJessica M. Terry1 aPhillip Belgrader1 aSolongo B. Ziraldo1 aTarjei S. Mikkelsen1 aPehr B. Harbury1 aJeffrey S. Glenn1 aK. Christopher Garcia1 aMark M. Davis1 aRalph S. Baric1 aChiara Sabatti1 aManuel R. Amieva1 aCatherine A. Blish1 aTushar J. Desai1 aCalvin J. Kuo00aProgenitor identification and SARS-CoV-2 infection in human distal lung organoids  uhttps://www.nature.com/articles/s41586-020-3014-1  a670-6750 v5883 aThe distal lung contains terminal bronchioles and alveoli that facilitate gas exchange. Three-dimensional in vitro human distal lung culture systems would strongly facilitate the investigation of pathologies such as interstitial lung disease, cancer and coronavirus disease 2019 (COVID-19) pneumonia caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Here we describe the development of a long-term feeder-free, chemically defined culture system for distal lung progenitors as organoids derived from single adult human alveolar epithelial type II (AT2) or KRT5+ basal cells. AT2 organoids were able to differentiate into AT1 cells, and basal cell organoids developed lumens lined with differentiated club and ciliated cells. Single-cell analysis of KRT5+ cells in basal organoids revealed a distinct population of ITGA6+ITGB4+ mitotic cells, whose offspring further segregated into a TNFRSF12Ahi subfraction that comprised about ten per cent of KRT5+ basal cells. This subpopulation formed clusters within terminal bronchioles and exhibited enriched clonogenic organoid growth activity. We created distal lung organoids with apical-out polarity to present ACE2 on the exposed external surface, facilitating infection of AT2 and basal cultures with SARS-CoV-2 and identifying club cells as a target population. This long-term, feeder-free culture of human distal lung organoids, coupled with single-cell analysis, identifies functional heterogeneity among basal cells and establishes a facile in vitro organoid model of human distal lung infections, including COVID-19-associated pneumonia.  a1476-4687