There are currently limited Food and Drug Administration (FDA)-approved drugs and vaccines for the treatment or prevention of Coronavirus Disease 2019 (COVID-19). Enhanced understanding of Severe ...Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection and pathogenesis is critical for the development of therapeutics. To provide insight into viral replication, cell tropism, and host-viral interactions of SARS-CoV-2, we performed single-cell (sc) RNA sequencing (RNA-seq) of experimentally infected human bronchial epithelial cells (HBECs) in air-liquid interface (ALI) cultures over a time course. This revealed novel polyadenylated viral transcripts and highlighted ciliated cells as a major target at the onset of infection, which we confirmed by electron and immunofluorescence microscopy. Over the course of infection, the cell tropism of SARS-CoV-2 expands to other epithelial cell types including basal and club cells. Infection induces cell-intrinsic expression of type I and type III interferons (IFNs) and interleukin (IL)-6 but not IL-1. This results in expression of interferon-stimulated genes (ISGs) in both infected and bystander cells. This provides a detailed characterization of genes, cell types, and cell state changes associated with SARS-CoV-2 infection in the human airway.
Measurements at high-Arctic sites (Alert, Nunavut, and Mt. Zeppelin, Svalbard) during the years 2011 to 2013 show a strong and similar annual cycle in aerosol number and size distributions. Each year ...at both sites, the number of aerosols with diameters larger than 20 nm exhibits a minimum in October and two maxima, one in spring associated with a dominant accumulation mode (particles 100 to 500 nm in diameter) and a second in summer associated with a dominant Aitken mode (particles 20 to 100 nm in diameter). Seasonal-mean aerosol effective diameter from measurements ranges from about 180 in summer to 260 nm in winter. This study interprets these annual cycles with the GEOS-Chem-TOMAS global aerosol microphysics model. Important roles are documented for several processes (new-particle formation, coagulation scavenging in clouds, scavenging by precipitation, and transport) in controlling the annual cycle in Arctic aerosol number and size. Our simulations suggest that coagulation scavenging of interstitial aerosols in clouds by aerosols that have activated to form cloud droplets strongly limits the total number of particles with diameters less than 200 nm throughout the year. We find that the minimum in total particle number in October can be explained by diminishing new-particle formation within the Arctic, limited transport of pollution from lower latitudes, and efficient wet removal. Our simulations indicate that the summertime-dominant Aitken mode is associated with efficient wet removal of accumulation-mode aerosols, which limits the condensation sink for condensable vapours. This in turn promotes new-particle formation and growth. The dominant accumulation mode during spring is associated with build up of transported pollution from outside the Arctic coupled with less-efficient wet-removal processes at colder temperatures. We recommend further attention to the key processes of new-particle formation, interstitial coagulation, and wet removal and their delicate interactions and balance in size-resolved aerosol simulations of the Arctic to reduce uncertainties in estimates of aerosol radiative effects on the Arctic climate.
Yu et al.’s study highlights the clinical utility of VE-cadherin as a potential biomarker of EC injury but falls short of providing mechanistic insight to EC dysfunction in critical illness. ......VE-cadherin may be shed in EC-derived microvesicles, which serve as signaling platforms to other ECs or immune cells 4. Open AccessThis article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.
Cellular diversity of the lung endothelium has not been systematically characterized in humans. We provide a reference atlas of human lung endothelial cells (ECs) to facilitate a better understanding ...of the phenotypic diversity and composition of cells comprising the lung endothelium.
We reprocessed human control single-cell RNA sequencing (scRNAseq) data from 6 datasets. EC populations were characterized through iterative clustering with subsequent differential expression analysis. Marker genes were validated by fluorescent microscopy and in situ hybridization. scRNAseq of primary lung ECs cultured in vitro was performed. The signaling network between different lung cell types was studied. For cross-species analysis or disease relevance, we applied the same methods to scRNAseq data obtained from mouse lungs or from human lungs with pulmonary hypertension.
Six lung scRNAseq datasets were reanalyzed and annotated to identify >15 000 vascular EC cells from 73 individuals. Differential expression analysis of EC revealed signatures corresponding to endothelial lineage, including panendothelial, panvascular, and subpopulation-specific marker gene sets. Beyond the broad cellular categories of lymphatic, capillary, arterial, and venous ECs, we found previously indistinguishable subpopulations; among venous EC, we identified 2 previously indistinguishable populations: pulmonary-venous ECs (COL15A1
) localized to the lung parenchyma and systemic-venous ECs (COL15A1
) localized to the airways and the visceral pleura; among capillary ECs, we confirmed their subclassification into recently discovered aerocytes characterized by
,
, and
and general capillary EC. We confirmed that all 6 endothelial cell types, including the systemic-venous ECs and aerocytes, are present in mice and identified endothelial marker genes conserved in humans and mice. Ligand-receptor connectome analysis revealed important homeostatic crosstalk of EC with other lung resident cell types. scRNAseq of commercially available primary lung ECs demonstrated a loss of their native lung phenotype in culture. scRNAseq revealed that endothelial diversity is maintained in pulmonary hypertension. Our article is accompanied by an online data mining tool (www.LungEndothelialCellAtlas.com).
Our integrated analysis provides a comprehensive and well-crafted reference atlas of ECs in the normal lung and confirms and describes in detail previously unrecognized endothelial populations across a large number of humans and mice.
Necrotizing enterocolitis (NEC) is a gastrointestinal complication of premature infants with high rates of morbidity and mortality. A comprehensive view of the cellular changes and aberrant ...interactions that underlie NEC is lacking. This study aimed at filling in this gap. We combine single-cell RNA sequencing (scRNAseq), T-cell receptor beta (TCRβ) analysis, bulk transcriptomics, and imaging to characterize cell identities, interactions, and zonal changes in NEC. We find an abundance of proinflammatory macrophages, fibroblasts, endothelial cells as well as T cells that exhibit increased TCRβ clonal expansion. Villus tip epithelial cells are reduced in NEC and the remaining epithelial cells up-regulate proinflammatory genes. We establish a detailed map of aberrant epithelial-mesenchymal-immune interactions that are associated with inflammation in NEC mucosa. Our analyses highlight the cellular dysregulations of NEC-associated intestinal tissue and identify potential targets for biomarker discovery and therapeutics.
Angiopoietin-like 4 (ANGPTL4) is known to regulate various cellular and systemic functions. However, its cell-specific role in endothelial cells (ECs) function and metabolic homeostasis remains to be ...elucidated. Here, using endothelial-specific Angptl4 knock-out mice (Angptl4
), and transcriptomics and metabolic flux analysis, we demonstrate that ANGPTL4 is required for maintaining EC metabolic function vital for vascular permeability and angiogenesis. Knockdown of ANGPTL4 in ECs promotes lipase-mediated lipoprotein lipolysis, which results in increased fatty acid (FA) uptake and oxidation. This is also paralleled by a decrease in proper glucose utilization for angiogenic activation of ECs. Mice with endothelial-specific deletion of Angptl4 showed decreased pathological neovascularization with stable vessel structures characterized by increased pericyte coverage and reduced permeability. Together, our study denotes the role of endothelial-ANGPTL4 in regulating cellular metabolism and angiogenic functions of EC.
Multisystem inflammatory syndrome in children (MIS-C) is a life-threatening post-infectious complication occurring unpredictably weeks after mild or asymptomatic SARS-CoV-2 infection. We profiled ...MIS-C, adult COVID-19, and healthy pediatric and adult individuals using single-cell RNA sequencing, flow cytometry, antigen receptor repertoire analysis, and unbiased serum proteomics, which collectively identified a signature in MIS-C patients that correlated with disease severity. Despite having no evidence of active infection, MIS-C patients had elevated S100A-family alarmins and decreased antigen presentation signatures, indicative of myeloid dysfunction. MIS-C patients showed elevated expression of cytotoxicity genes in NK and CD8+ T cells and expansion of specific IgG-expressing plasmablasts. Clinically severe MIS-C patients displayed skewed memory T cell TCR repertoires and autoimmunity characterized by endothelium-reactive IgG. The alarmin, cytotoxicity, TCR repertoire, and plasmablast signatures we defined have potential for application in the clinic to better diagnose and potentially predict disease severity early in the course of MIS-C.
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•scRNA-seq of PBMCs from MIS-C patients reveals immunopathology signatures•MIS-C patients display elevated alarmins and NK/CD8+ T cell cytotoxicity effectors•TRBV11-2-expressing CD4+ and CD8+ memory T cells are expanded in severe MIS-C•Increased plasmablasts and endothelium-reactive IgG are features of severe MIS-C
Multisystem inflammatory syndrome in children (MIS-C) is a life-threatening and unpredictable condition of unknown etiology. Ramaswamy et al. use peripheral blood single-cell transcriptomic profiling along with other techniques to define key innate and adaptive signatures that characterize MIS-C.
Transport of anthropogenic aerosol into the Arctic in the spring
months has the potential to affect regional climate; however, modeling
estimates of the aerosol direct radiative effect (DRE) are ...sensitive to
uncertainties in the mixing state of black carbon (BC). A common approach in
previous modeling studies is to assume an entirely external mixture (all
primarily scattering species are in separate particles from BC) or internal
mixture (all primarily scattering species are mixed in the same particles as
BC). To provide constraints on the size-resolved mixing state of BC, we use
airborne single-particle soot photometer (SP2) and ultrahigh-sensitivity
aerosol spectrometer (UHSAS) measurements from the Alfred Wegener Institute
(AWI) Polar 6 flights from the NETCARE/PAMARCMIP2015 campaign to estimate
coating thickness as a function of refractory BC (rBC) core diameter and
the fraction of particles containing rBC in the springtime Canadian high
Arctic. For rBC core diameters in the range of 140 to 220 nm, we find
average coating thicknesses of approximately 45 to 40 nm, respectively,
resulting in ratios of total particle diameter to rBC core diameters ranging
from 1.6 to 1.4. For total particle diameters ranging from 175 to 730 nm,
rBC-containing particle number fractions range from 16 % to 3 %,
respectively. We combine the observed mixing-state constraints with simulated
size-resolved aerosol mass and number distributions from GEOS-Chem–TOMAS to
estimate the DRE with observed bounds on mixing state as opposed to assuming
an entirely external or internal mixture. We find that the pan-Arctic average
springtime DRE ranges from −1.65 to −1.34 W m−2 when assuming
entirely externally or internally mixed BC. This range in DRE is reduced by
over a factor of 2 (−1.59 to −1.45 W m−2) when using the
observed mixing-state constraints. The difference in DRE between the two
observed mixing-state constraints is due to an underestimation of BC mass
fraction in the springtime Arctic in GEOS-Chem–TOMAS compared to Polar 6
observations. Measurements of mixing state provide important constraints for
model estimates of DRE.
To review, analyze, and synthesize the literature on endothelial dysfunction in critically ill children with multiple organ dysfunction syndrome and to develop a consensus biomarker-based definition ...and diagnostic criteria.
Electronic searches of PubMed and Embase were conducted from January 1992 to January 2020, using a combination of medical subject heading terms and key words to define concepts of endothelial dysfunction, pediatric critical illness, and outcomes.
Studies were included if they evaluated critically ill children with endothelial dysfunction, evaluated performance characteristics of assessment/scoring tools to screen for endothelial dysfunction, and assessed outcomes related to mortality, functional status, organ-specific outcomes, or other patient-centered outcomes. Studies of adults or premature infants (≤36 weeks gestational age), animal studies, reviews or commentaries, case series with sample size ≤10, and non-English language studies with the inability to determine eligibility criteria were excluded.
Data were abstracted from each eligible study into a standard data extraction form along with risk of bias assessment.
We identified 62 studies involving 84 assessments of endothelial derived biomarkers indirectly linked to endothelial functions including leukocyte recruitment, inflammation, coagulation, and permeability. Nearly all biomarkers studied lacked specificity for vascular segment and organ systems. Quality assessment scores for the collected literature were low.
The Endothelial Subgroup concludes that there exists no single or combination of biomarkers to diagnose endothelial dysfunction in pediatric multiple organ dysfunction syndrome. Future research should focus on biomarkers more directly linked to endothelial functions and with specificity for vascular segment and organ systems.
Endothelial cells (ECs) line the lumen of the entire vascular system and actively regulate blood flow; maintain blood fluidity; control water, solute, and macromolecular transfer between blood and ...tissue; and modulate circulating immune cell recruitment and activation. These vital functions, combined with the broad anatomic distribution of ECs, implicate them in all forms of critical illness. The present article discusses how ECs adapt and break down during the course of critical illness. We first review the biology of ECs, highlighting the vascular segmental differences and their specific roles in the maintenance of homeostasis. We then discuss how ECs acquire new functions to restore local and systemic homeostasis (activation) as well as how breakdowns in EC functions (dysfunction) contribute to local and systemic pathologic responses, with clinical correlations. Lastly, how these processes have been studied in critically ill children is discussed.
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