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Nature Communications Oct 2023Influenza virus infection causes increased morbidity and mortality in the elderly. Aging impairs the immune response to influenza, both intrinsically and because of...
Influenza virus infection causes increased morbidity and mortality in the elderly. Aging impairs the immune response to influenza, both intrinsically and because of altered interactions with endothelial and pulmonary epithelial cells. To characterize these changes, we performed single-cell RNA sequencing (scRNA-seq), spatial transcriptomics, and bulk RNA sequencing (bulk RNA-seq) on lung tissue from young and aged female mice at days 0, 3, and 9 post-influenza infection. Our analyses identified dozens of key genes differentially expressed in kinetic, age-dependent, and cell type-specific manners. Aged immune cells exhibited altered inflammatory, memory, and chemotactic profiles. Aged endothelial cells demonstrated characteristics of reduced vascular wound healing and a prothrombotic state. Spatial transcriptomics identified novel profibrotic and antifibrotic markers expressed by epithelial and non-epithelial cells, highlighting the complex networks that promote fibrosis in aged lungs. Bulk RNA-seq generated a timeline of global transcriptional activity, showing increased expression of genes involved in inflammation and coagulation in aged lungs. Our work provides an atlas of high-throughput sequencing methodologies that can be used to investigate age-related changes in the response to influenza virus, identify novel cell-cell interactions for further study, and ultimately uncover potential therapeutic targets to improve health outcomes in the elderly following influenza infection.
Topics: Humans; Female; Animals; Mice; Aged; Influenza, Human; Endothelial Cells; Lung; Epithelial Cells; Orthomyxoviridae Infections
PubMed: 37852965
DOI: 10.1038/s41467-023-42021-y -
JAMA Nov 2023Red blood cell (RBC) transfusion is common among patients admitted to the intensive care unit (ICU). Despite multiple randomized clinical trials of hemoglobin (Hb)...
IMPORTANCE
Red blood cell (RBC) transfusion is common among patients admitted to the intensive care unit (ICU). Despite multiple randomized clinical trials of hemoglobin (Hb) thresholds for transfusion, little is known about how these thresholds are incorporated into current practice.
OBJECTIVE
To evaluate and describe ICU RBC transfusion practices worldwide.
DESIGN, SETTING, AND PARTICIPANTS
International, prospective, cohort study that involved 3643 adult patients from 233 ICUs in 30 countries on 6 continents from March 2019 to October 2022 with data collection in prespecified weeks.
EXPOSURE
ICU stay.
MAIN OUTCOMES AND MEASURES
The primary outcome was the occurrence of RBC transfusion during ICU stay. Additional outcomes included the indication(s) for RBC transfusion (consisting of clinical reasons and physiological triggers), the stated Hb threshold and actual measured Hb values before and after an RBC transfusion, and the number of units transfused.
RESULTS
Among 3908 potentially eligible patients, 3643 were included across 233 ICUs (median of 11 patients per ICU [IQR, 5-20]) in 30 countries on 6 continents. Among the participants, the mean (SD) age was 61 (16) years, 62% were male (2267/3643), and the median Sequential Organ Failure Assessment score was 3.2 (IQR, 1.5-6.0). A total of 894 patients (25%) received 1 or more RBC transfusions during their ICU stay, with a median total of 2 units per patient (IQR, 1-4). The proportion of patients who received a transfusion ranged from 0% to 100% across centers, from 0% to 80% across countries, and from 19% to 45% across continents. Among the patients who received a transfusion, a total of 1727 RBC transfusions were administered, wherein the most common clinical indications were low Hb value (n = 1412 [81.8%]; mean [SD] lowest Hb before transfusion, 7.4 [1.2] g/dL), active bleeding (n = 479; 27.7%), and hemodynamic instability (n = 406 [23.5%]). Among the events with a stated physiological trigger, the most frequently stated triggers were hypotension (n = 728 [42.2%]), tachycardia (n = 474 [27.4%]), and increased lactate levels (n = 308 [17.8%]). The median lowest Hb level on days with an RBC transfusion ranged from 5.2 g/dL to 13.1 g/dL across centers, from 5.3 g/dL to 9.1 g/dL across countries, and from 7.2 g/dL to 8.7 g/dL across continents. Approximately 84% of ICUs administered transfusions to patients at a median Hb level greater than 7 g/dL.
CONCLUSIONS AND RELEVANCE
RBC transfusion was common in patients admitted to ICUs worldwide between 2019 and 2022, with high variability across centers in transfusion practices.
Topics: Adult; Humans; Male; Middle Aged; Female; Erythrocyte Transfusion; Anemia; Cohort Studies; Prospective Studies; Transfusion Medicine; Hemoglobins; Intensive Care Units
PubMed: 37824112
DOI: 10.1001/jama.2023.20737 -
The Journal of Clinical Investigation Feb 2024Pulmonary arterial hypertension (PAH) is a devastating and progressive disease with limited treatment options. Endothelial dysfunction plays a central role in the...
Pulmonary arterial hypertension (PAH) is a devastating and progressive disease with limited treatment options. Endothelial dysfunction plays a central role in the development and progression of PAH, yet the underlying mechanisms are incompletely understood. The endosome-lysosome system is important to maintain cellular health, and the small GTPase RAB7 regulates many functions of this system. Here, we explored the role of RAB7 in endothelial cell (EC) function and lung vascular homeostasis. We found reduced expression of RAB7 in ECs from patients with PAH. Endothelial haploinsufficiency of RAB7 caused spontaneous pulmonary hypertension (PH) in mice. Silencing of RAB7 in ECs induced broad changes in gene expression revealed via RNA-Seq, and RAB7-silenced ECs showed impaired angiogenesis and expansion of a senescent cell fraction, combined with impaired endolysosomal trafficking and degradation, suggesting inhibition of autophagy at the predegradation level. Furthermore, mitochondrial membrane potential and oxidative phosphorylation were decreased, and glycolysis was enhanced. Treatment with the RAB7 activator ML-098 reduced established PH in rats with chronic hypoxia/SU5416. In conclusion, we demonstrate for the first time to our knowledge the fundamental impairment of EC function by loss of RAB7, causing PH, and show RAB7 activation to be a potential therapeutic strategy in a preclinical model of PH.
Topics: Animals; Humans; Mice; Rats; Familial Primary Pulmonary Hypertension; Hypertension, Pulmonary; Hypoxia; Lung; Pulmonary Artery
PubMed: 38015641
DOI: 10.1172/JCI169441 -
Cell Reports Jun 2023Systemic inflammation is established as part of late-stage severe lung disease, but molecular, functional, and phenotypic changes in peripheral immune cells in early...
Systemic inflammation is established as part of late-stage severe lung disease, but molecular, functional, and phenotypic changes in peripheral immune cells in early disease stages remain ill defined. Chronic obstructive pulmonary disease (COPD) is a major respiratory disease characterized by small-airway inflammation, emphysema, and severe breathing difficulties. Using single-cell analyses we demonstrate that blood neutrophils are already increased in early-stage COPD, and changes in molecular and functional neutrophil states correlate with lung function decline. Assessing neutrophils and their bone marrow precursors in a murine cigarette smoke exposure model identified similar molecular changes in blood neutrophils and precursor populations that also occur in the blood and lung. Our study shows that systemic molecular alterations in neutrophils and their precursors are part of early-stage COPD, a finding to be further explored for potential therapeutic targets and biomarkers for early diagnosis and patient stratification.
Topics: Humans; Animals; Mice; Neutrophils; Pulmonary Disease, Chronic Obstructive; Lung; Pulmonary Emphysema; Inflammation
PubMed: 37243592
DOI: 10.1016/j.celrep.2023.112525 -
Signal Transduction and Targeted Therapy Oct 2023Patients with chronic obstructive pulmonary disease (COPD) who exhibit elevated blood eosinophil levels often experience worsened lung function and more severe...
Patients with chronic obstructive pulmonary disease (COPD) who exhibit elevated blood eosinophil levels often experience worsened lung function and more severe emphysema. This implies the potential involvement of eosinophils in the development of emphysema. However, the precise mechanisms underlying the development of eosinophil-mediated emphysema remain unclear. In this study, we employed single-cell RNA sequencing to identify eosinophil subgroups in mouse models of asthma and emphysema, followed by functional analyses of these subgroups. Assessment of accumulated eosinophils unveiled distinct transcriptomes in the lungs of mice with elastase-induced emphysema and ovalbumin-induced asthma. Depletion of eosinophils through the use of anti-interleukin-5 antibodies ameliorated elastase-induced emphysema. A particularly noteworthy discovery is that eosinophil-derived cathepsin L contributed to the degradation of the extracellular matrix, thereby leading to emphysema in pulmonary tissue. Inhibition of cathepsin L resulted in a reduction of elastase-induced emphysema in a mouse model. Importantly, eosinophil levels correlated positively with serum cathepsin L levels, which were higher in emphysema patients than those without emphysema. Expression of cathepsin L in eosinophils demonstrated a direct association with lung emphysema in COPD patients. Collectively, these findings underscore the significant role of eosinophil-derived cathepsin L in extracellular matrix degradation and remodeling, and its relevance to emphysema in COPD patients. Consequently, targeting eosinophil-derived cathepsin L could potentially offer a therapeutic avenue for emphysema patients. Further investigations are warranted to explore therapeutic strategies targeting cathepsin L in emphysema patients.
Topics: Animals; Humans; Mice; Asthma; Cathepsin L; Emphysema; Eosinophils; Lung; Pancreatic Elastase; Pulmonary Disease, Chronic Obstructive; Pulmonary Emphysema
PubMed: 37816708
DOI: 10.1038/s41392-023-01634-x -
Science Immunology Dec 2023Studies of human lung development have focused on epithelial and mesenchymal cell types and function, but much less is known about the developing lung immune cells, even...
Studies of human lung development have focused on epithelial and mesenchymal cell types and function, but much less is known about the developing lung immune cells, even though the airways are a major site of mucosal immunity after birth. An unanswered question is whether tissue-resident immune cells play a role in shaping the tissue as it develops in utero. Here, we profiled human embryonic and fetal lung immune cells using scRNA-seq, smFISH, and immunohistochemistry. At the embryonic stage, we observed an early wave of innate immune cells, including innate lymphoid cells, natural killer cells, myeloid cells, and lineage progenitors. By the canalicular stage, we detected naive T lymphocytes expressing high levels of cytotoxicity genes and the presence of mature B lymphocytes, including B-1 cells. Our analysis suggests that fetal lungs provide a niche for full B cell maturation. Given the presence and diversity of immune cells during development, we also investigated their possible effect on epithelial maturation. We found that IL-1β drives epithelial progenitor exit from self-renewal and differentiation to basal cells in vitro. In vivo, IL-1β-producing myeloid cells were found throughout the lung and adjacent to epithelial tips, suggesting that immune cells may direct human lung epithelial development.
Topics: Humans; Immunity, Innate; Cell Differentiation; Lung; Killer Cells, Natural; Epithelial Cells
PubMed: 38100545
DOI: 10.1126/sciimmunol.adf9988 -
Immunity Jan 2024The regulation of polymorphonuclear leukocyte (PMN) function by mechanical forces encountered during their migration across restrictive endothelial cell junctions is not...
The regulation of polymorphonuclear leukocyte (PMN) function by mechanical forces encountered during their migration across restrictive endothelial cell junctions is not well understood. Using genetic, imaging, microfluidic, and in vivo approaches, we demonstrated that the mechanosensor Piezo1 in PMN plasmalemma induced spike-like Ca signals during trans-endothelial migration. Mechanosensing increased the bactericidal function of PMN entering tissue. Mice in which Piezo1 in PMNs was genetically deleted were defective in clearing bacteria, and their lungs were predisposed to severe infection. Adoptive transfer of Piezo1-activated PMNs into the lungs of Pseudomonas aeruginosa-infected mice or exposing PMNs to defined mechanical forces in microfluidic systems improved bacterial clearance phenotype of PMNs. Piezo1 transduced the mechanical signals activated during transmigration to upregulate nicotinamide adenine dinucleotide phosphate (NADPH) oxidase 4, crucial for the increased PMN bactericidal activity. Thus, Piezo1 mechanosensing of increased PMN tension, while traversing the narrow endothelial adherens junctions, is a central mechanism activating the host-defense function of transmigrating PMNs.
Topics: Animals; Mice; Cell Membrane; Cell Movement; Ion Channels; Lung; Neutrophils; Blood Bactericidal Activity; Mechanotransduction, Cellular
PubMed: 38091995
DOI: 10.1016/j.immuni.2023.11.007 -
The Journal of Allergy and Clinical... Aug 2023Group 2 innate lymphoid cells (ILC2s) are critical mediators of type 2 respiratory inflammation, releasing IL-5 and IL-13 and promoting the pulmonary eosinophilia...
BACKGROUND
Group 2 innate lymphoid cells (ILC2s) are critical mediators of type 2 respiratory inflammation, releasing IL-5 and IL-13 and promoting the pulmonary eosinophilia associated with allergen provocation. Although ILC2s have been shown to promote eosinophil activities, the role of eosinophils in group 2 innate lymphoid cell (ILC2) responses is less well defined.
OBJECTIVE
We sought to investigate the role of eosinophils in activation of ILC2s in models of allergic asthma and in vitro.
METHODS
Inducible eosinophil-deficient mice were exposed to allergic respiratory inflammation models of asthma, such as ovalbumin or house dust mite challenge, or to innate models of type 2 airway inflammation, such as inhalation of IL-33. Eosinophil-specific IL-4/13-deficient mice were used to address the specific roles for eosinophil-derived cytokines. Direct cell interactions between ILC2s and eosinophils were assessed by in vitro culture experiments.
RESULTS
Targeted depletion of eosinophils resulted in significant reductions of total and IL-5 and IL-13 lung ILC2s in all models of respiratory inflammation. This correlated with reductions in IL-13 levels and mucus in the airway. Eosinophil-derived IL-4/13 was necessary for both eosinophil and ILC2 accumulation in lung in allergen models. In vitro, eosinophils released soluble mediators that induced ILC2 proliferation and G protein-coupled receptor-dependent chemotaxis of ILC2s. Coculture of ILC2s and IL-33-activated eosinophils resulted in transcriptome changes in both ILC2s and eosinophils, suggesting potential novel reciprocal interactions.
CONCLUSION
These studies demonstrate that eosinophils play a reciprocal role in ILC2 effector functions as part of both adaptive and innate type 2 pulmonary inflammatory events.
Topics: Mice; Animals; Immunity, Innate; Eosinophils; Interleukin-33; Interleukin-13; Interleukin-5; Interleukin-4; Lymphocytes; Lung; Cytokines; Asthma; Inflammation; Allergens
PubMed: 37028525
DOI: 10.1016/j.jaci.2023.03.023 -
Immunity Sep 2023Arginase 1 (Arg1), the enzyme catalyzing the conversion of arginine to ornithine, is a hallmark of IL-10-producing immunoregulatory M2 macrophages. However, its...
Arginase 1 (Arg1), the enzyme catalyzing the conversion of arginine to ornithine, is a hallmark of IL-10-producing immunoregulatory M2 macrophages. However, its expression in T cells is disputed. Here, we demonstrate that induction of Arg1 expression is a key feature of lung CD4 T cells during mouse in vivo influenza infection. Conditional ablation of Arg1 in CD4 T cells accelerated both virus-specific T helper 1 (Th1) effector responses and its resolution, resulting in efficient viral clearance and reduced lung pathology. Using unbiased transcriptomics and metabolomics, we found that Arg1-deficiency was distinct from Arg2-deficiency and caused altered glutamine metabolism. Rebalancing this perturbed glutamine flux normalized the cellular Th1 response. CD4 T cells from rare ARG1-deficient patients or CRISPR-Cas9-mediated ARG1-deletion in healthy donor cells phenocopied the murine cellular phenotype. Collectively, CD4 T cell-intrinsic Arg1 functions as an unexpected rheostat regulating the kinetics of the mammalian Th1 lifecycle with implications for Th1-associated tissue pathologies.
Topics: Animals; Humans; Mice; Arginase; CD4-Positive T-Lymphocytes; Glutamine; Influenza, Human; Kinetics; Lung; Mammals
PubMed: 37572656
DOI: 10.1016/j.immuni.2023.07.014 -
International Journal of Chronic... 2023Airway inflammation, driven by different types of inflammatory cells and mediators, plays a fundamental role in COPD and its progression. Neutrophils, eosinophils,... (Review)
Review
Airway inflammation, driven by different types of inflammatory cells and mediators, plays a fundamental role in COPD and its progression. Neutrophils, eosinophils, macrophages, and CD4 and CD8 T lymphocytes are key players in this process, although the extent of their participation varies according to the patient's endotype. Anti-inflammatory medications may modify the natural history and progression of COPD. However, since airway inflammation in COPD is relatively resistant to corticosteroid therapy, innovative pharmacological anti-inflammatory approaches are required. The heterogeneity of inflammatory cells and mediators in annethe different COPD endo-phenotypes requires the development of specific pharmacologic agents. Indeed, over the past two decades, several mechanisms that influence the influx and/or activity of inflammatory cells in the airways and lung parenchyma have been identified. Several of these molecules have been tested in vitro models and in vivo in laboratory animals, but only a few have been studied in humans. Although early studies have not been encouraging, useful information emerged suggesting that some of these agents may need to be further tested in specific subgroups of patients, hopefully leading to a more personalized approach to treating COPD.
Topics: Animals; Humans; Pulmonary Disease, Chronic Obstructive; Lung; Eosinophils; Neutrophils; Inflammation; Anti-Inflammatory Agents
PubMed: 37408603
DOI: 10.2147/COPD.S419056