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Author(s): Ameen A. Salahudeen [sup.1] [sup.19] , Shannon S. Choi [sup.1] , Arjun Rustagi [sup.2] , Junjie Zhu [sup.3] , Vincent van Unen [sup.4] [sup.5] , Sean M. de la [...], The 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.sup.+ 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.sup.+ cells in basal organoids revealed a distinct population of ITGA6.sup.+ITGB4.sup.+ mitotic cells, whose offspring further segregated into a TNFRSF12A.sup.hi subfraction that comprised about ten per cent of KRT5.sup.+ 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. A long-term culture method for organoids derived from single adult human lung cells is used to identify progenitor cells and study SARS-CoV-2 infection.

Author(s): Kyle J. Travaglini [sup.1] [sup.2] , Ahmad N. Nabhan [sup.1] [sup.2] [sup.12] , Lolita Penland [sup.3] [sup.13] , Rahul Sinha [sup.4] [sup.5] , Astrid Gillich [sup.1] [sup.2] , Rene [...], Although single-cell RNA sequencing studies have begun to provide compendia of cell expression profiles.sup.1-9, it has been difficult to systematically identify and localize all molecular cell types in individual organs to create a full molecular cell atlas. Here, using droplet- and plate-based single-cell RNA sequencing of approximately 75,000 human cells across all lung tissue compartments and circulating blood, combined with a multi-pronged cell annotation approach, we create an extensive cell atlas of the human lung. We define the gene expression profiles and anatomical locations of 58 cell populations in the human lung, including 41 out of 45 previously known cell types and 14 previously unknown ones. This comprehensive molecular atlas identifies the biochemical functions of lung cells and the transcription factors and markers for making and monitoring them; defines the cell targets of circulating hormones and predicts local signalling interactions and immune cell homing; and identifies cell types that are directly affected by lung disease genes and respiratory viruses. By comparing human and mouse data, we identified 17 molecular cell types that have been gained or lost during lung evolution and others with substantially altered expression profiles, revealing extensive plasticity of cell types and cell-type-specific gene expression during organ evolution including expression switches between cell types. This atlas provides the molecular foundation for investigating how lung cell identities, functions and interactions are achieved in development and tissue engineering and altered in disease and evolution. Expression profiling on 75,000 single cells creates a comprehensive cell atlas of the human lung that includes 41 out of 45 previously known cell types and 14 new ones.

Introduction Bone morphogenetic proteins (BMPs) are a group of signaling molecules that belong to the transforming growth factor-p (TGF-[beta]) superfamily of proteins. BMPs have multiple roles in the development and [...], Bone morphogenetic proteins (BMPs) were once considered only to have a role in bone formation. It is now known that they have pivotal roles in other organ diseases, including heritable pulmonary arterial hypertension (PAH), where genetic mutations in the type II BMP receptor (BMPR2) are the commonest cause of receptor dysfunction. However, it has also recently been demonstrated that aquaporin 1 (Aqp1) dysfunction may contribute to PAH, highlighting that PAH development may involve more than one pathogenic pathway. Whether reduction in BMPR2 affects Aqp1 is unknown. We therefore studied Aqp1 in BMPR2-silenced human pulmonary microvascular endothelial cells (HPMECs). We demonstrated reduced Aqp1 mRNA protein, and function in the BMPR2-silenced cells. Additionally, BMPR2-silenced cells exhibited lower expression of BMP-signaling molecules. In conclusion, decreased BMPR2 appears to affect Aqp1 at the mRNA, protein, and functional levels. This observation may identify a contributory mechanism for PAH. Key words: Aqp1, BMPR2, PAH, HPMEC. On a deja considere que les proteines morphogeniques osseuses (BMP pour << bone morphogenetic proteins >>) jouent uniquement un role dans la formation d&apos;os. On sait maintenant qu&apos;elles jouent un role central dans d&apos;autres maladies, y compris l&apos;hypertension arterielle pulmonaire hereditaire (HAP), ou des mutations genetiques dans les recepteurs aux BMP de type 2 (BMPR2) sont la cause la plus frequente de dysfonctionnement des recepteurs. Toutefois, on a aussi montre recemment qu&apos;un dysfonctionnement de l&apos;aquaporine 1 (Aqp1) pourrait contribuer a l&apos;HAP, ce qui met en relief que l&apos;apparition de l&apos;HAP pourrait mettre enjeu plus d&apos;une voie de signalisation de pathogenie. On ne sait pas si l&apos;abaissement des BMPR2 affecte l&apos;Aqp1. Nous avons donc etudie l&apos;Aqp1 dans des cellules endotheliales de microvaisseaux pulmonaires humains (CEMPH) dont les BMPR2 etaient reprimes. Nous avons montre un abaissement de l&apos;Aqp1 en ARNm, en proteines et quant au fonctionnement dans des cellules dont les BMPR2 etaient reprimes. De plus, les cellules dont les BMPR2 etaient reprimes presentaient une plus faible expression de molecules de signalisation des BMP. En conclusion, l&apos;abaissement des BMPR2 semble affecter l&apos;Aqp1 au niveau de l&apos;ARNm, des proteines et du fonctionnement. Cette observation pourrait permettre de distinguer un mode d&apos;action qui contribuerait a l&apos;HAP. [Traduit par la Redaction] Mots-cles: Aqp1, BMPR2, hypertension arterielle pulmonaire hereditaire, cellules endotheliales de microvaisseaux pulmonaires humains.

Introduction While transplantation has become an accepted form of therapy for end-stage organ failure, formidable immunologic barriers limit long-term allograft survival. The currently accepted clinical immunosuppression protocols, consisting of life-long [...], Memory T lymphocytes are commonly viewed as a major barrier for long-term survival of organ allografts and are thought to accelerate rejection responses due to their rapid infiltration into allografts, low threshold for activation, and ability to produce inflammatory mediators. Because memory T cells are usually associated with rejection, preclinical protocols have been developed to target this population in transplant recipients. Here, using a murine model, we found that costimulatory blockade--mediated lung allograft acceptance depended on the rapid infiltration of the graft by central memory [CD8.sup.+] T cells ([CD44.sup.hi][CD62L.sup.hi][CCR7.sup.+]). Chemokine receptor signaling and alloantigen recognition were required for trafficking of these memory T cells to lung allografts. Intravital 2-photon imaging revealed that CCR7 expression on [CD8.sup.+] T cells was critical for formation of stable synapses with antigen-presenting cells, resulting in IFN-γ production, which induced NO and downregulated alloimmune responses. Thus, we describe a critical role for [CD8.sup.+] central memory T cells in lung allograft acceptance and highlight the need for tailored approaches for tolerance induction in the lung.

Introduction Organ cross-talk is of particular importance to practitioners in the intensive care unit (ICU); many disease processes that affect ICU patients carry the potential to affect a number of [...], There is a growing appreciation for the role that acute kidney injury (AKI) plays in the propagation of critical illness. In children, AKI is not only an independent predictor of morbidity and mortality, but is also associated with especially negative outcomes when concurrent with acute lung injury (ALI). Experimental data provide evidence that kidney-lung crosstalk occurs and can be bidirectionally deleterious, although details of the precise molecular mechanisms involved in the AKI-ALI interaction remain incomplete. Clinically, ALI, and the subsequent clinical interventions used to stabilize gas exchange, carry consequences for the homeostasis of kidney function. Meanwhile, AKI negatively affects lung physiology significantly by altering the homeostasis of fluid balance, acid-base balance, and vascular tone. Experimental AKI research supports an 'endocrine' role for the kidney, triggering a cascade of extra-renal inflammatory responses affecting lung homeostasis. In this review, we will discuss the pathophysiologyof kidney-lung crosstalk, the multiple pathways by which AKI affects kidney-lung homeostasis, and discuss how these phenomena may be unique in critically ill children. Understanding how AKI may affect a 'balance of communication' that exists between the kidneys and the lungs is requisite when managing critically ill children, in whom imbalance is the norm. Keywords kidney-lung crosstalk * AKI * ALI * Fluid overload * Renal angina

Introduction Studies indicate that traumatic injury induces immune dysfunction, which is associated with an increased susceptibility to sepsis, organ failure, and mortality [1-5]. Increased susceptibility to infection and a higher [...], Although several clinical studies show a gender dimorphism of immune and organ responsiveness in the susceptibility to and morbidity from shock, trauma, and sepsis, there are conflicting reports on the role of gender in outcomes. In contrast, results obtained from experimental studies clearly support the suggestion that gender plays a significant role in post-injury pathogenesis. Studies performed in a rodent model of trauma-hemorrhage have confirmed that alterations in immune and organ functions after trauma-hemorrhage are more markedly depressed in adult males and in ovariectomized and aged females; however, both are maintained in castrated males and in proestrus females. Moreover, the survival rate of proestrus females subjected to sepsis after trauma-hemorrhage is significantly higher than in age-matched males or ovariectomized females. In this respect, organ functions and immune responses are depressed in males with sepsis or trauma, whereas they are unchanged or are enhanced in females. This article reviews studies delineating the mechanism by which estrogen regulates cerebral nervous, lung, and heart systems in an experimental model of sepsis, trauma, or reperfusion injury. Keywords Shock * Trauma * Males * Females * Sepsis * Reperfusion * Estrogen

Author(s): Emma Lefrançais [1]; Guadalupe Ortiz-Muñoz [1]; Axelle Caudrillier [1]; Beñat Mallavia [1]; Fengchun Liu [1]; David M. Sayah [2]; Emily E. Thornton [3]; Mark B. Headley [3]; Tovo David [...]

Introduction Acrolein (2,3-propenal) is a reactive aldehyde used in the chemical industry for synthesis of organic compounds, in the production of methionine, and in methyl chloride refrigerant. Acrolein can be [...], Background: Acrolein is a ubiquitous environmental hazard to human health. Acrolein has been reported to activate the DNA damage response and induce apoptosis. However, little is known about the effects of acrolein on cellular senescence. OBJECTIVES: We examined whether acrolein induces cellular senescence in cultured normal human lung fibroblasts (NHLF). METHODS: We cultured NHLF in the presence or absence of acrolein and determined the effects of acrolein on cell proliferative capacity, senescence-associated (3-galactosidase activity, the known senescence-inducing pathways (e.g., p53, p21), and telomere length. RESULTS: We found that acrolein induced cellular senescence by increasing both p53 and p21. The knockdown of p53 mediated by small interfering RNA (siRNA) attenuated acrolein-induced cellular senescence. Acrolein decreased Werner's syndrome protein (WRN), a member of the RecQ helicase family involved in DNA repair and telomere maintenance. Acrolein-induced down-regulation of WRN protein was rescued by p53 knockdown or proteasome inhibition. Finally, we found that acrolein accelerated p53-mediated telomere shortening. CONCLUSIONS: These results suggest that acrolein induces p53-mediated cellular senescence accompanied by enhanced telomere attrition and WRN protein down-regulation. http://dx.doi.org/10.1289/ehp.1306911

Author(s): Christo Goridis (corresponding author) [1] As we breathe, our lungs and airways are continuously exposed to extensive mechanical forces. For instance, during exercise, the average man can inhale 3.5 [...]

Introduction Lung function is an objective marker of respiratory health and a predictor of cardio-respiratory morbidity and mortality (Sin et al. 2005). The long-term effects of ambient air pollution on [...], BACKGROUND: There is evidence for adverse effects of outdoor air pollution on lung function of children. Quantitative summaries of the effects of air pollution on lung function, however, are lacking due to large differences among studies. OBJECTIVES: We aimed to study the association between residential exposure to air pollution and lung function in five European birth cohorts with a standardized exposure assessment following a common protocol. METHODS: As part of the European Study of Cohorts for Air Pollution Effects (ESCAPE) we analyzed data from birth cohort studies situated in Germany, Sweden, the Netherlands, and the United Kingdom that measured lung function at 6-8 years of age (n = 5,921). Annual average exposure to air pollution [nitrogen oxides (N[O.sub.2], N[O.sub.x]), mass concentrations of particulate matter with diameters < 2.5, < 10, and 2.5-10 µm ([PM.sub.2.5], [PM.sub.10], and [PM.sub.coarse]), and [PM.sub.2.5] absorbance] at the birth address and current address was estimated by land-use regression models. Associations of lung function with estimated air pollution levels and traffic indicators were estimated for each cohort using linear regression analysis, and then combined by random effects meta- analysis. RESULTS: Estimated levels of N[O.sub.2], N[O.sub.x], [PM.sub.2.5] absorbance, and [PM.sub.2.5] at the current address, but not at the birth address, were associated with small decreases in lung function. For example, changes in forced expiratory volume in 1 sec ([FEV.sub.1]) ranged from -0.86% (95% CI: -1.48, -0.24%) for a 20-µg/[m.sup.3] increase in N[O.sub.x] to -1.77% (95% CI: - 3.34, -0.18%) for a 5-µg/[m.sup.3] increase in [PM.sub.2.5]. CONCLUSIONS: Exposure to air pollution may result in reduced lung function in schoolchildren.