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BackgroundEffective regulation of complement activation may be crucial to preserving complement function during ARDS. Factor H (FH) is the primary negative regulator of the alternative pathway (AP) of complement. We hypothesized that preserved FH levels are associated with decreased complement activation and reduced mortality during ARDS.MethodsTotal AP function was measured by serum hemolytic assay (AH50) using available samples from the ARDSnet LARMA trial (N=218). Factor B (FB) and FH levels were quantified by ELISA using samples from the ARDSnet LARMA and SAILS (N=224) trials. Meta-analyses included previously quantified AH50, FB, and FH values from an observational registry (ALIR). Complement C3, and complement activation products C3a and Ba plasma levels were measured in SAILS.ResultsAH50>median was associated with reduced mortality in meta-analysis of LARMA and ALIR [hazard ratio (HR)=0.66, 95% confidence interval (CI) 0.45–0.96]. In contrast, patients in the lowest AH50 quartile demonstrated relative deficiency of both FB and FH. Relative deficiency of FB [HR 1.99, CI 1.44–2.75], or FH [HR 1.52, CI 1.09–2.11], were associated with increased mortality in meta-analysis of LARMA, SAILS, and ALIR. Relative FH deficiency was associated with increased factor consumption as evidenced by lower FB and C3 levels and higher Ba:FB and C3a:C3 ratios. Higher FH levels associated with lower inflammatory markers.ConclusionsRelative FH deficiency, higher Ba:FB and C3a:C3 ratios, and lower FB and C3 levels suggest a subset of ARDS with complement factor exhaustion, impaired AP function, and increased mortality that may be amenable to therapeutic targeting.

Background Fatty acid oxidation (FAO) defects have been implicated in experimental models of acute lung injury and associated with poor outcomes in critical illness. In this study, we examined acylcarnitine profiles and 3-methylhistidine as markers of FAO defects and skeletal muscle catabolism, respectively, in patients with acute respiratory failure. We determined whether these metabolites were associated with host-response ARDS subphenotypes, inflammatory biomarkers, and clinical outcomes in acute respiratory failure. Methods In a nested case–control cohort study, we performed targeted analysis of serum metabolites of patients intubated for airway protection (airway controls), Class 1 (hypoinflammatory), and Class 2 (hyperinflammatory) ARDS patients (N = 50 per group) during early initiation of mechanical ventilation. Relative amounts were quantified by liquid chromatography high resolution mass spectrometry using isotope-labeled standards and analyzed with plasma biomarkers and clinical data. Results Of the acylcarnitines analyzed, octanoylcarnitine levels were twofold increased in Class 2 ARDS relative to Class 1 ARDS or airway controls (P = 0.0004 and P = 0.004). In addition, acetylcarnitine and 3-methylhistidine were increased in Class 2 relative to Class 1 and positively correlated with inflammatory biomarkers. In all patients within the study with acute respiratory failure, increased 3-methylhistidine was observed in non-survivors at 30 days (P = 0.0018), while octanoylcarnitine was increased in patients requiring vasopressor support but not in non-survivors (P = 0.0001 and P = 0.28, respectively). Conclusions This study demonstrates that increased levels of acetylcarnitine, octanoylcarnitine, and 3-methylhistidine distinguish Class 2 from Class 1 ARDS patients and airway controls. Octanoylcarnitine and 3-methylhistidine were associated with poor outcomes in patients with acute respiratory failure across the cohort independent of etiology or host-response subphenotype. These findings suggest a role for serum metabolites as biomarkers in ARDS and poor outcomes in critically ill patients early in the clinical course.

Immune tolerance to allergens in early-life decreases the risk for asthma in later life. Here we show establishment of stable airway tolerance to the allergen, house dust mite (HDM), by exposing newborn mice repeatedly to a low dose of the allergen. Lung dendritic cells (DCs) from tolerized mice induced a low Th2 response in vitro mirroring impact of tolerance in vivo. In line with our previous finding of increased mitochondrial H2O2 production from lung DCs of mice tolerized to ovalbumin, depletion of mitochondrial H2O2 in MCAT mice abrogated HDM-induced airway tolerance (Tol) with elevated Th2 effector response, airway eosinophilia, and increased airway hyperreactivity. WT-Tol mice displayed a decrease in total, cDC1 and cDC2 subsets in the lung as compared to that in naive mice. In contrast, the lungs of MCAT-Tol mice showed 3-fold higher numbers of cDCs including those of the subsets as compared to that in WT mice. Our study demonstrates an important role of mitochondrial H2O2 in constraining lung DC numbers towards establishment of early-life airway tolerance to allergens.

PurposeEnhanced understanding of the dynamic changes in the dysregulated inflammatory response in COVID-19 may help improve patient selection and timing for immunomodulatory therapies.MethodsWe enrolled 323 COVID-19 inpatients on different levels of baseline respiratory support: i) Low Flow Oxygen (37%), ii) Non-Invasive Ventilation or High Flow Oxygen (NIV_HFO, 29%), iii) Invasive Mechanical Ventilation (IMV, 27%), and iv) Extracorporeal Membrane Oxygenation (ECMO, 7%). We collected plasma samples upon enrollment and days 5 and 10 to measure host-response biomarkers. We classified subjects into inflammatory subphenotypes using two validated predictive models. We examined clinical, biomarker and subphenotype trajectories and outcomes during hospitalization.ResultsIL-6, procalcitonin, and Angiopoietin-2 were persistently elevated in patients at higher levels of respiratory support, whereas sRAGE displayed the inverse pattern. Patients on NIV_HFO at baseline had the most dynamic clinical trajectory, with 26% eventually requiring intubation and exhibiting worse 60-day mortality than IMV patients at baseline (67% vs. 35%, pConclusionsLongitudinal study of systemic host responses in COVID-19 revealed substantial and predictive inter-individual variability, influenced by baseline levels of respiratory support and concurrent immunomodulatory therapies.

Rationale: Complement is crucial for host defense but may also drive dysregulated inflammation. There is limited understanding of alternative complement function, which can amplify all complement a...

The present study briefs the structural and optical properties of Gd doped BaZr0.05Ti0.95O3 ceramic synthesized via solid-state reaction (SSR) technique. The X-Ray diffraction (XRD) study reveals t...

Plasma SARS-CoV-2 viral RNA (vRNA) levels are predictive of COVID-19 outcomes in hospitalized patients, but whether plasma vRNA reflects lower respiratory tract (LRT) vRNA levels is unclear. We compared plasma and LRT vRNA levels in serially collected samples from mechanically ventilated patients with COVID-19. LRT and plasma vRNA levels were strongly correlated at first sampling (n = 33, r = 0.83, P < 10−9) and then declined in parallel in available serial samples except in nonsurvivors who exhibited delayed vRNA clearance in LRT samples. Plasma vRNA measurement may offer a practical surrogate of LRT vRNA burden in critically ill patients, especially early after ICU admission.

Classification of patients with acute respiratory distress syndrome into hyper- and hypoinflammatory subphenotypes using plasma biomarkers may facilitate more effective targeted therapy. We examined whether established subphenotypes are present not only in patients with acute respiratory distress syndrome but also in patients at risk for acute respiratory distress syndrome (ARFA) and then assessed the prognostic information of baseline subphenotyping on the evolution of host-response biomarkers and clinical outcomes.Prospective, observational cohort study.Medical ICU at a tertiary academic medical center.Mechanically ventilated patients with acute respiratory distress syndrome or ARFA.None.We performed longitudinal measurements of 10 plasma biomarkers of host injury and inflammation. We applied unsupervised latent class analysis methods utilizing baseline clinical and biomarker variables and demonstrated that two-class models (hyper- vs hypoinflammatory subphenotypes) offered improved fit compared with one-class models in both patients with acute respiratory distress syndrome and ARFA. Baseline assignment to the hyperinflammatory subphenotype (39/104 [38%] acute respiratory distress syndrome and 30/108 [28%] ARFA patients) was associated with higher severity of illness by Sequential Organ Failure Assessment scores and incidence of acute kidney injury in patients with acute respiratory distress syndrome, as well as higher 30-day mortality and longer duration of mechanical ventilation in ARFA patients (p0.0001). Hyperinflammatory patients exhibited persistent elevation of biomarkers of innate immunity for up to 2 weeks postintubation.Our results suggest that two distinct subphenotypes are present not only in patients with established acute respiratory distress syndrome but also in patients at risk for its development. Hyperinflammatory classification at baseline is associated with higher severity of illness, worse clinical outcomes, and trajectories of persistently elevated biomarkers of host injury and inflammation during acute critical illness compared with hypoinflammatory patients. Our findings provide strong rationale for examining treatment effect modifications by subphenotypes in randomized clinical trials to inform precision therapeutic approaches in critical care.

While there have been extensive analyses characterizing cellular and humoral responses across the severity spectrum in COVID-19, predictors of outcomes within severe COVID-19 remain to be comprehensively elucidated. Recently, we identified divergent monocyte states as predictors of outcomes within severe COVID-19, but corresponding humoral profiles of risk have not been delineated. Furthermore, the nature of antibodies (Abs) directed against viral antigens beyond the spike protein or endemic coronavirus antigens and their associations with disease severity and outcomes remain poorly defined. We performed deep molecular profiling of Abs directed against a wide range of antigenic specificities in severe COVID-19 patients admitted to the ICU. The profiles consisted of canonical (S, RBD, N) and non-canonical (orf3a, orf8, nsp3, nps13 and M) antigenic specificities. Notably, multivariate machine learning (ML) models, generated using profiles of Abs directed against canonical or non-canonical antigens, were equally discriminative of recovery and mortality COVID-19 outcomes. In both ML models, survivors were associated with increased virus-specific IgA and IgG3 antibodies and with higher antigen-specific antibody galactosylation. Intriguingly, pre-pandemic healthy controls had cross-reactive Abs directed against nsp13 which is a conserved protein in other alpha and beta coronaviruses. Notably, higher levels of nsp13-specific IgA antibodies were associated with recovery in severe COVID-19. In keeping with these findings, a model built on Ab profiles for endemic coronavirus antigens was also predictive of COVID-19 outcome bifurcation, with higher levels of IgA and IgG3 antibodies against OC43 S and NL63 S being associated with survival. Our results suggest the importance of Abs targeting non-canonical SARS-CoV-2 antigens as well as those directed against endemic coronaviruses in favorable outcomes of severe COVID-19.

Immune tolerance to allergens in early-life decreases the risk for asthma in later life. Here we show establishment of stable airway tolerance to the allergen, house dust mite (HDM), by exposing newborn mice repeatedly to a low dose of the allergen. Lung dendritic cells (DCs) from tolerized mice induced a low Th2 response in vitro mirroring impact of tolerance in vivo. In line with our previous finding of increased mitochondrial H

Thrombocytopenia is associated with worse outcomes in patients with acute respiratory distress syndrome, which is most commonly caused by infection and marked by alveolar–capillary barrier disruption. However, the mechanisms by which platelets protect the lung alveolar–capillary barrier during infectious injury remain unclear. We found that natively thrombocytopenic Mpl−/− mice deficient in the thrombopoietin receptor sustain severe lung injury marked by alveolar barrier disruption and hemorrhagic pneumonia with early mortality following acute intrapulmonary Pseudomonas aeruginosa (PA) infection; barrier disruption was attenuated by platelet reconstitution. Although PA infection was associated with a brisk neutrophil influx, depletion of airspace neutrophils failed to substantially mitigate PA-triggered alveolar barrier disruption in Mpl−/− mice. Rather, PA cell-free supernatant was sufficient to induce lung epithelial cell apoptosis in vitro and in vivo and alveolar barrier disruption in both platelet-depleted mice and Mpl−/− mice in vivo. Cell-free supernatant from PA with genetic deletion of the type 2 secretion system, but not the type 3 secretion system, mitigated lung epithelial cell death in vitro and lung injury in Mpl−/− mice. Moreover, platelet releasates reduced poly (ADP ribose) polymerase cleavage and lung injury in Mpl−/− mice, and boiling of platelet releasates, but not apyrase treatment, abrogated PA supernatant–induced lung epithelial cell cytotoxicity in vitro. These findings indicate that while neutrophil airspace influx does not potentiate infectious lung injury in the thrombocytopenic host, platelets and their factors protect against severe pulmonary complications from pathogen-secreted virulence factors that promote host cell death even in the absence of overt infection.

We study the geomagnetic activity Ap-index in relation to sunspot number and area for the interval covering Solar Cycles 17 to 24 (1932 – 2019), in view of the availability of data for the Ap-index from 1932 on, in order to predict the amplitude of Sunspot Cycle 25. We examine the statistical relationship between sunspot-maximum amplitude and Ap-index, and similarly that between sunspot area and Ap-index. We apply the $\chi ^{2}$ -test for the best fit between two parameters and obtain the correlation coefficient. We also derive the standard deviation for the error limits in the predicted results. Our study reveals that the amplitude of the Sunspot Cycle 25 is likely to be $\approx 100.21 \pm 15.06$ and it may peak in April $2025\pm 6.5$ months. On the other hand, the sunspot area will have maximum amplitude $\approx 1110.62 \pm 186.87$ μ Hem and may peak in February $2025\pm 5.8$ months, which implies that Solar Cycle 25 will be weaker than or comparable to Solar Cycle 24. In view of our results as well as those of other investigators, we propose that the Sun is perhaps approaching a global minimum.

Coronavirus disease 2019 (COVID-19) caused by SARS-CoV-2 infection presents with varied clinical manifestations1, ranging from mild symptoms to acute respiratory distress syndrome (ARDS) with high mortality2,3. Despite extensive analyses, there remains an urgent need to delineate immune cell states that contribute to mortality in severe COVID-19. We performed high-dimensional cellular and molecular profiling of blood and respiratory samples from critically ill COVID-19 patients to define immune cell genomic states that are predictive of outcome in severe COVID-19 disease. Critically ill patients admitted to the intensive care unit (ICU) manifested increased frequencies of inflammatory monocytes and plasmablasts that were also associated with ARDS not due to COVID-19. Single-cell RNAseq (scRNAseq)-based deconvolution of genomic states of peripheral immune cells revealed distinct gene modules that were associated with COVID-19 outcome. Notably, monocytes exhibited bifurcated genomic states, with expression of a cytokine gene module exemplified by CCL4 (MIP-1β) associated with survival and an interferon signaling module associated with death. These gene modules were correlated with higher levels of MIP-1β and CXCL10 levels in plasma, respectively. Monocytes expressing genes reflective of these divergent modules were also detectable in endotracheal aspirates. Machine learning algorithms identified the distinctive monocyte modules as part of a multivariate peripheral immune system state that was predictive of COVID-19 mortality. Follow-up analysis of the monocyte modules on ICU day 5 was consistent with bifurcated states that correlated with distinct inflammatory cytokines. Our data suggests a pivotal role for monocytes and their specific inflammatory genomic states in contributing to mortality in life-threatening COVID-19 disease and may facilitate discovery of new diagnostics and therapeutics.

SUMMARY Clinical definitions of asthma fail to capture the heterogeneity of immune dysfunction in severe, treatment-refractory disease. Applying mass cytometry and machine learning to bronchoalveolar lavage (BAL) cells, we find that corticosteroid-resistant asthma patients cluster largely into two groups: one enriched in interleukin (IL)-4+ innate immune cells and another dominated by interferon (IFN)-γ+ T cells, including tissue-resident memory cells. In contrast, BAL cells of a healthier population are enriched in IL-10+ macrophages. To better understand cellular mediators of severe asthma, we developed the Immune Cell Linkage through Exploratory Matrices (ICLite) algorithm to perform deconvolution of bulk RNA sequencing of mixed-cell populations. Signatures of mitosis and IL-7 signaling in CD206−FcεRI+CD127+IL-4+ innate cells in one patient group, contrasting with adaptive immune response in T cells in the other, are preserved across technologies. Transcriptional signatures uncovered by ICLite identify T-cell-high and T-cell-poor severe asthma patients in an independent cohort, suggesting broad applicability of our findings., Graphical abstract, In brief Asthma is an immune-mediated heterogeneous disease. Current type-2 biomarkers provide limited understanding of underlying pathobiology or therapeutic guidance. Using a multi-omics approach, Camiolo et al. identify two clusters of severe asthma patients with similar type-2 biomarkers but with strikingly distinct immune profiles and associated biological pathways.

Macrophages are main effectors of heme metabolism, increasing transiently in the liver during heightened disposal of damaged or senescent red blood cells (sRBC). Macrophages are also essential in defense against microbial threats, but pathologic states of heme excess may be immunosuppressive. Herein, we uncovered a mechanism whereby an acute rise in sRBC disposal by macrophages led to an immunosuppressive phenotype following intrapulmonary Klebsiella pneumoniae infection characterized by increased extrapulmonary bacterial proliferation and reduced survival from sepsis in mice. The impaired immunity to K. pneumoniae during heightened sRBC disposal was independent of iron acquisition by bacterial siderophores, as K. pneumoniae mutant lacking siderophore function recapitulated findings observed with wildtype strain. Rather, sRBC disposal induced a liver transcriptomic profile notable for suppression of Stat1 and interferon-related responses during K. pneumoniae sepsis. Excess heme handling by macrophages recapitulated STAT1 suppression during infection that required synergistic NRF1 and NRF2 activation but was independent of heme oxygenase-1 induction. Whereas iron was dispensable, the porphyrin moiety of heme was sufficient to mediate suppression of STAT1-dependent responses in human and mouse macrophages and promoted liver dissemination of K. pneumoniae in vivo. Thus, cellular heme metabolism dysfunction negatively regulates the STAT1 pathway with implications in severe infection.

BACKGROUND: Many severe asthma (SA) patients fail to respond to Type 2 inflammation targeted therapies. We previously identified a cohort of SA subjects expressing Type 1 inflammation manifesting with IFN-γ expression with variable Type 2 responses. OBJECTIVE: We investigated the role of the chemotactic receptors CXCR3 and CCR5 in establishing Type 1 inflammation in SA. METHODS: Bronchoalveolar lavage microarray data from the Severe Asthma Research Program (SARP I/II) were analyzed for pathway expression and paired with clinical parameters. Wild Type, Cxcr3(−/−) and Ccr5(−/−) mice were exposed to a Type 1(High) SA model with analysis of whole lung gene expression and histology. Wild type and Cxcr3(−/−) mice were treated with an FDA-approved CCR5 inhibitor (maraviroc) with assessment of airway resistance, inflammatory cell recruitment by flow cytometry, whole lung gene expression and histology. RESULTS: A cohort of subjects with increased IFN-γ expression showed higher asthma severity. IFN-γ expression correlated with CXCR3 and CCR5 expression but in Cxcr3(−/−) and Ccr5(−/−) mice Type 1 inflammation was preserved in a murine SA model, most likely due to compensation by the other pathway. Incorporation of maraviroc in the experimental model blunted airway hyperreactivity, despite only mild effects on lung inflammation. CONCLUSIONS: IFNG expression in asthmatic airways was strongly correlated with expression of both the chemokine receptors CXCR3 and CCR5. While these pathways provide redundancy for establishing Type 1 lung inflammation, inhibition of the CCL5/CCR5 pathway with maraviroc provided unique benefits in reducing airway hyperreactivity. Targeting this pathway may be a novel approach for improving lung function in Type 1(high) asthmatic individuals. CLINICAL IMPLICATIONS: In Type 1 high asthma, CCR5 and CXCR3 provide redundant pathways for lung inflammation, but CCR5 inhibition provides a potential novel target for reducing airway hyperreactivity.

Acute respiratory distress syndrome (ARDS) results from overwhelming pulmonary inflammation. Prior bulk RNA sequencing provided limited insights into ARDS pathogenesis. We used single cell RNA sequencing to probe ARDS at a higher resolution. PBMCs of patients with pneumonia and sepsis with early ARDS were compared with those of sepsis patients who did not develop ARDS. Monocyte clusters from ARDS patients revealed multiple distinguishing characteristics in comparison with monocytes from patients without ARDS, including downregulation of SOCS3 expression, accompanied by a proinflammatory signature with upregulation of multiple type I IFN–induced genes, especially in CD16(+) cells. To generate an ARDS risk score, we identified upregulation of 29 genes in the monocytes of these patients, and 17 showed a similar profile in cells of patients in independent cohorts. Monocytes had increased expression of RAB11A, known to inhibit neutrophil efferocytosis; ATP2B1, a calcium pump that exports Ca(2+) implicated in endothelial barrier disruption; and SPARC, associated with processing of procollagen to collagen. These data show that monocytes of ARDS patients upregulate expression of genes not just restricted to those associated with inflammation. Together, our findings identify molecules that are likely involved in ARDS pathogenesis that may inform biomarker and therapeutic development.

Despite extensive analyses, there remains an urgent need to delineate immune cell states that contribute to mortality in critically ill Coronavirus disease 2019 (COVID-19) patients. Here, we present high-dimensional profiling of blood and respiratory samples in severe COVID-19 patients to examine the association between cell-linked molecular features and mortality outcomes. Peripheral transcriptional profiles by single-cell RNAseq based deconvolution of immune states are associated with COVID-19 mortality. Further, persistently high levels of an interferon signaling module in monocytes over time leads to subsequent concerted upregulation of inflammatory cytokines. SARS-CoV-2 infected myeloid cells in the lower respiratory tract upregulate CXCL10, leading to a higher risk of death. Our analysis suggests a pivotal role for viral infected myeloid cells and protracted interferon signaling in severe COVID-19., Graphical Abstract, Cillo et al identify transcriptional profiles in peripheral blood that are associated with mortality in critically ill COVID-19 patients. Inflammatory monocyte signatures are correlated with CXCL10 in plasma and precede upregulation of inflammatory cytokines in blood. SARS-CoV-2-infected macrophages in the respiratory tract expressed CXCL10, linking peripheral and lung immune profiles.

A novel tapioca starch (TS)-based energy efficient natural sizing technology for sizing jute yarn was developed. The performance of the developed formulation was tested in a laboratory at pilot scale and subsequently validated through industrial-level shop floor trials vis-a-vis the conventional tamarind kernel powder (TKP)-based sizing. Unlike TKP sizing, the developed natural size paste formulation did not require “cooking” at elevated temperature, and could be maintained at room temperature in sow box. In addition, TS-based sized yarns could be dried at lower temperature. TS-sized jute yarns showed better abrasion resistance, and slightly better tensile strength values when compared with conventional TKP-sized yarns. TS-based sized jute yarns exhibited better elastic recovery compared with TKP-sized yarns under cyclic loading. The sizing effluents were found to be drastically reduced in TS-based recipe showing lower Biological Oxygen Demand and Chemical Oxygen Demand. Using TS-based sizing formulation,...

BACKGROUND Exposure to innocuous inhaled foreign antigens such as dust mite and pollen triggers aberrant immune responses in the respiratory tract of individuals genetically predisposed to asthma. Immune tolerance restricts such overreaction and plays a key role in preventing unwanted inflammatory responses. Yet the mechanisms underlying this protection are still largely unclear. Our studies of immune tolerance in regulation of experimental asthma and those of others in the context of cancer demonstrated PPARγ-facilitated fatty acid oxidation (FAO) resulting in mitochondrial H2O2 production in dendritic cells (DCs) in promotion of immune tolerance. However, neither study addressed whether mitochondrial H2O2 is essential for suppression of inflammation in response to antigens. OBJECTIVE In this study, we sought to establish a mouse model of airway tolerance to inhaled house dust mite (HDM) allergen in newborn mice and study the role of mitochondrial H2O2 in tolerance establishment. METHODS AND RESULTS Repeated exposure of wild type (WT) mice to a low dose of the common allergen HDM in early life suppressed airway inflammation and airway hyperreactivity when the mice were challenged by a high dose of the allergen in adulthood. This protective effect was abolished in MCAT transgenic mice, which overexpress the catalase gene in their mitochondria. The inflammatory phenotype in the MCAT mice was associated with a high TH2 response facilitated by lung dendritic cells (DCs). CONCLUSIONS Our study illustrates a crucial role of mitochondrial H2O2 in the establishment of airway tolerance in early life, which suppresses DC-mediated TH2 response.

OBJECTIVE To study the ability of the host protective cytokine interleukin-22 (IL-22) to block productive infection of airway epithelial cells by Respiratory Syncytial Virus (RSV). BACKGROUND RSV infection can cause severe bronchiolitis and pneumonia in infants. However, no vaccine against RSV is currently available. RSV primarily infects both proximal and distal airways as well as alveolar epithelial cells in the lungs. IL-22 has mucosal-protective effects, known to preserve epithelial-barrier functions and promote host defense against pathogens. We, therefore, initiated studies to determine whether IL-22 can control RSV infection of airway epithelial cells (AECs). METHODS Primary human AECs differentiated under air-liquid interface (ALI) culture conditions were used for RSV infection (multiplicity of infection (MOI) 2) and then treated with IL-22 (50 ng/ml). 5-day old newborn C57BL/6 mice were intranasally infected with 1×106 PFU of RSV and then treated with an IL-22-Fc fusion protein (5 μg/mouse) intraperitoneally on day 3 p.i. Confocal imaging approach was utilized to determine co-localization of RSV and LC3B and to differentiate between autophagosomes and autolysosomes. RESULTS Treatment with IL-22 led to a significant decrease in viral load in primary human AECs as well as in vivo in mouse lungs. Confocal imaging and other approaches revealed subversion of the autophagic machinery by RSV for its own production, which was significantly inhibited by IL-22, thereby preserving autophagy in a STAT3 dependent manner. CONCLUSIONS IL-22 inhibits RSV production in both primary human airway epithelial cells and mouse lungs by preserving cellular autophagy thereby blocking hijacking of the autophagic apparatus by RSV.

Background 5–10% of severe asthmatics are resistant to corticosteroids but account for 50% of health care costs spent on asthma care in the US and in Europe. 30–40% of corticosteroid-resistant severe asthmatic patients show elevated IFN-γ levels (Type1 immune response) in BAL cells that is closely associated with expression of CXCL10, a downstream IFN-γ target, and a marker of senescence associated secretory phenotype (SASP). Objective The goal of this study was to evaluate the role of SASP in severe asthma associated with an elevated level of corticosteroid-refractory IFN-γ in the airways. Methods Wild type BALB/c and IFN-γ−/− mice were sensitized with house dust mite (HDM) in combination with cdi-GMP and then subsequently repeatedly challenged with HDM. Lungs from these and control mice were subjected to either RNA-seq analysis or used for β-gal staining to demonstrate cellular senescence. Results Whole lungs from WT mice subjected to the severe asthma (SA) model demonstrated significantly higher expression of several SASP genes which included p16INK4a, CXCL10, MMP12 and IL-6 as compared to that detected in naïve WT mice. p16INK4a is a key regulator of premature cellular senescence that arrests cell cycle in G1 phase by inhibiting CDK4 and CDK6 and has been associated with corticosteroid resistance. Further, the SASP genes p16INK4a, CXCL10 and CCL8 were downregulated in the absence of IFN-γ suggesting a possible role of elevated IFN-γ in SASP induction. The lung sections from mice subjected to the SA model showed increased numbers of b-gal positive cells as compared to that found in control mice. Conclusion SASP may underlie persistent inflammation and corticosteroid resistance observed in a subset of severe asthma patients.

The acute respiratory distress syndrome (ARDS) is a common etiology of acute respiratory failure that results from overwhelming pulmonary inflammation. Since prior bulk RNA sequence analyses have provided limited insights into ARDS pathogenesis, we used the approach of single cell RNA sequencing (scRNA-seq) to probe ARDS at a higher resolution. Towards this end, scRNA-seq data of peripheral blood mononuclear cells (PBMCs) of patients with pneumonia and sepsis with early ARDS were compared to that of sepsis patients who did not develop ARDS. We detected a previously unrecognized reduced frequency of NK cells in the PBMCs of ARDS patients, which also showed complete loss of IFNGR1 expression. Monocyte clusters from ARDS patients revealed multiple distinguishing characteristics in comparison to monocytes from patients without ARDS. This included a pro-inflammatory signature with up-regulation of multiple type I IFN-induced genes, especially in CD16+ cells. To generate an ARDS risk score, we identified 29 differentially expressed genes in the monocytes of these patients, 17 of which showed a similar profile in cells of patients in independent cohorts. Genes with increased expression in monocytes that may have relevance in ARDS pathogenesis include RAB11A, known to inhibit neutrophil efferocytosis, ATP2B1, a calcium pump that exports Ca2+ implicated in endothelial barrier disruption, and SPARC, associated with processing of pro-collagen to collagen. Together, our findings identify molecules that are likely involved in ARDS pathogenesis that may inform biomarker and therapeutic development.

Streptococcus pneumoniae is an important bacterial pathogen that causes a range of noninvasive and invasive diseases. The mechanisms underlying variability in the ability of S. pneumoniae to transition from nasopharyngeal colonization to disease-causing pathogen are not well defined. Mucosal-associated invariant T (MAIT) cells are prevalent in mucosal tissues such as the airways and are believed to play an important role in the early response to infection with bacterial pathogens. The ability of MAIT cells to recognize and contain infection with S. pneumoniae is not known. In the present study, we analyzed MAIT-cell responses to infection with clinical isolates of S. pneumoniae serotype 19A, a serotype linked to invasive pneumococcal disease. We found that although MAIT cells were capable of responding to human dendritic and airway epithelial cells infected with S. pneumoniae, the magnitude of response to different serotype 19A isolates was determined by genetic differences in the expression of the riboflavin biosynthesis pathway. MAIT-cell release of cytokines correlated with differences in the ability of MAIT cells to respond to and control S. pneumoniae in vitro and in vivo in a mouse challenge model. Together, these results demonstrate first that there are genetic differences in riboflavin metabolism among clinical isolates of the same serotype and second that these likely determine MAIT-cell function in response to infection with S. pneumoniae. These differences are critical when considering the role that MAIT cells play in early responses to pneumococcal infection and determining whether invasive disease will develop.

The respiratory tract maintains immune homeostasis despite constant provocation by environmental Ags. Failure to induce tolerogenic responses to allergens incites allergic inflammation. Despite the understanding that APCs have a crucial role in maintaining immune tolerance, the underlying mechanisms are poorly understood. Using mice with a conditional deletion of peroxisome proliferator-activated receptor γ (PPARγ) in CD11c+ cells, we show that PPARγ performs two critical functions in CD11c+ cells to induce tolerance, thereby preserving immune homeostasis. First, PPARγ was crucial for the induction of retinaldehyde dehydrogenase (aldh1a2) selectively in CD103+ dendritic cells, which we recently showed promotes Foxp3 expression in naive CD4+ T cells. Second, in all CD11c+ cells, PPARγ was required to suppress expression of the Th17-skewing cytokines IL-6 and IL-23p19. Also, lack of PPARγ in CD11c+ cells induced p38 MAPK activity, which was recently linked to Th17 development. Thus, PPARγ favors immune tolerance by promoting regulatory T cell generation and blocking Th17 differentiation.

Severe asthma (SA) is a significant problem both clinically and economically, given its poor response to corticosteroids (CS). We recently reported a complex type 1-dominated (IFN-γ-dominated) immune response in more than 50% of severe asthmatics despite high-dose CS treatment. Also, IFN-γ was found to be critical for increased airway hyperreactivity (AHR) in our model of SA. The transcription factor IRF5 expressed in M1 macrophages can induce a Th1/Th17 response in cocultured human T cells. Here we show markedly higher expression of IRF5 in bronchoalveolar lavage (BAL) cells of severe asthmatics as compared with that in cells from milder asthmatics or healthy controls. Using our SA mouse model, we demonstrate that lack of IRF5 in lymph node migratory DCs severely limits their ability to stimulate the generation of IFN-γ- and IL-17-producing CD4+ T cells and IRF5-/- mice subjected to the SA model displayed significantly lower IFN-γ and IL-17 responses, albeit showing a reciprocal increase in Th2 response. However, the absence of IRF5 rendered the mice responsive to CS with suppression of the heightened Th2 response. These data support the notion that IRF5 inhibition in combination with CS may be a viable approach to manage disease in a subset of severe asthmatics.

Bacterial pneumonia is a significant healthcare burden worldwide. Failure to resolve inflammation after infection precipitates lung injury and an increase in morbidity and mortality. Gram-negative bacteria are common in pneumonia and increased levels of the mito-damage-associated molecular pattern (DAMP) cardiolipin can be detected in the lungs. Here we show that mice infected with Klebsiella pneumoniae develop lung injury with accumulation of cardiolipin. Cardiolipin inhibits resolution of inflammation by suppressing production of anti-inflammatory IL-10 by lung CD11b+Ly6GintLy6CloF4/80+ cells. Cardiolipin induces PPARγ SUMOylation, which causes recruitment of a repressive NCOR/HDAC3 complex to the IL-10 promoter, but not the TNF promoter, thereby tipping the balance towards inflammation rather than resolution. Inhibition of HDAC activity by sodium butyrate enhances recruitment of acetylated histone 3 to the IL-10 promoter and increases the concentration of IL-10 in the lungs. These findings identify a mechanism of persistent inflammation during pneumonia and indicate the potential of HDAC inhibition as a therapy., Non-resolving bacterial pneumonia results in lung tissue damage owing to overactive inflammation. Here the authors show that the mitochondrial DAMP cardiolipin contributes to persistent inflammation by SUMOylating PPARγ, which promotes binding of the corepressor NCOR/HDAC3 complex to the IL-10 promoter.

Severe refractory asthma is associated with enhanced nitrative stress. To determine the mechanisms for high nitrative stress in human severe asthma (SA), 3-nitrotyrosine (3NT) was compared with Th1 and Th2 cytokine expression. In SA, high 3NT levels were associated with high interferon (IFN)-γ and low interleukin (IL)-13 expression, both of which have been reported to increase inducible nitric oxide synthase (iNOS) in human airway epithelial cells (HAECs). We found that IL-13 and IFN-γ synergistically enhanced iNOS, nitrite, and 3NT, corresponding with increased H(2)O(2). Catalase inhibited whereas superoxide dismutase enhanced 3NT formation, supporting a critical role for H(2)O(2), but not peroxynitrite, in 3NT generation. Dual oxidase-2 (DUOX2), central to H(2)O(2) formation, was also synergistically induced by IL-13 and IFN-γ. The catalysis of nitrite and H(2)O(2) to nitrogen dioxide radical (NO(2)(•)) requires an endogenous peroxidase in this epithelial cell system. Thyroid peroxidase (TPO) was identified by microarray analysis ex vivo as a gene distinguishing HAEC of SA from controls. IFN-γ induced TPO in HAEC and small interfering RNA knockdown decreased nitrated tyrosine residues. Ex vivo, DUOX2, TPO, and iNOS were higher in SA and correlated with 3NT. Thus, a novel iNOS-DUOX2-TPO-NO(2)(•) metabolome drives nitrative stress in HAEC and likely in SA.

Summary: Acute lung injury (ALI) is linked to mitochondrial injury, resulting in impaired cellular oxygen utilization; however, it is unknown how these events are linked on the molecular level. Cardiolipin, a mitochondrial-specific lipid, is generated by cardiolipin synthase (CLS1). Here, we show that S. aureus activates a ubiquitin E3 ligase component, Fbxo15, that is sufficient to mediate proteasomal degradation of CLS1 in epithelia, resulting in decreased cardiolipin availability and disrupted mitochondrial function. CLS1 is destabilized by the phosphatase and tensin homolog (PTEN)-induced putative kinase 1 (PINK1), which binds CLS1 to phosphorylate and regulates CLS1 disposal. Like Fbxo15, PINK1 interacts with and regulates levels of CLS1 through a mechanism dependent upon Thr219. S. aureus infection upregulates this Fbxo15-PINK1 pathway to impair mitochondrial integrity, and Pink1 knockout mice are less prone to S. aureus-induced ALI. Thus, ALI-associated disruption of cellular bioenergetics involves bioeffectors that utilize a phosphodegron to elicit ubiquitin-mediated disposal of a key mitochondrial enzyme. : It is unknown why people with severe bacterial infections develop mitochondrial dysfunction with impaired cellular oxygenation. Here, Mallampalli and colleagues show that S. aureus lung infection in cells and mice induces an ubiquitin E3 ligase subunit to mediate degradation of a mitochondrial biosynthetic enzyme, CLS1, after its phosphorylation by PINK1. The data provide mechanistic insights into mitochondrial bioenergetics during pneumonia.

Asthma constitutes a spectrum of conditions that affect a substantial proportion of the population in developed countries. A large segment of asthmatics are characterized by an immunologic type 2 allergic profile. A preponderance of conventional and biologically-based therapies are available to treat these subjects. However, a small minority of individuals clinically classified as severe asthmatics (SA), are highly refractory to treatment and account for a significantly disproportionate share of the clinical and economic impact of the asthma condition as a whole. In order to better define the immune response in SA with the ultimate goal of developing novel therapeutic modalities, we analyzed bronchoalveolar lavage (BAL) cells from a cohort of SA, mild to moderate asthmatics (M/M), and healthy controls by mass cytometry (CyTOF). Unbiased bioinformatic assessment revealed 34 clusters of BAL cells with assignment of subjects to one of four groupings by principal component analysis (PCA). The majority of SA (78.9%) fell into two of these groups and constituted 65.2% of their makeup, with M/M representing the remaining 34.8%. Similarly, analysis of airway bronchial epithelial cells (BECs) by RNA sequencing (RNASeq) revealed three subject groups with SA falling largely into one of these. Synthesis of CyTOF and RNASeq data in the context of relevant clinical parameters resulted in a combined profile for each subject, which was able to distinguish those with the most severe disease. Our approach demonstrates that an unbiased, multifactorial assessment of immune and epithelial profiles can predict asthma severity, but may also reveal mechanism-based clues for targeted, personalized therapeutic intervention in severe asthmatics.

Ramie (Boehmeria nivea), commonly known as China grass, is the strongest and finest plant fibre which is considered one of the valuable textile entities. Despite its unique characteristics, ramie has received reasonably less importance specially in the Indian subcontinent due to unavailability of appropriate postharvesting and processing technologies. With increase in global environmental awareness, the alternative (to cotton) cellulosic natural fibre “ramie” is gaining importance in the international textile domain. Sustainable methods and technologies which could trigger the utilization of ramie fibre are in demand worldwide. This paper will describe the developments carried out in the areas of postharvesting and spinning process of ramie. An ecofriendly degumming technology of ramie fibre has been elaborated along with suitable fibre processing route of ramie-jute blends that will bring new avenue for manufacturing jute diversified market acceptable products.

Bacterial pneumonia remains a significant burden worldwide. Although an inflammatory response in the lung is required to fight the causative agent, persistent tissue-resident neutrophils in non-resolving pneumonia can induce collateral tissue damage and precipitate acute lung injury. However, little is known about mechanisms orchestrated in the lung tissue that remove apoptotic neutrophils to restore tissue homeostasis. In mice infected with Klebsiella pneumoniae, a bacterium commonly associated with hospital-acquired pneumonia, we show that interleukin (IL)-10 is essential for resolution of lung inflammation and recovery of mice after infection. Although IL-10(-/-) mice cleared bacteria, they displayed increased morbidity with progressive weight loss and persistent lung inflammation in the later phase after infection. A source of tissue IL-10 was found to be resident CD11b(+)Gr1(int)F4/80(+) cells resembling myeloid-derived suppressor cells (MDSCs) that appeared with a delayed kinetics after infection. These cells efficiently efferocytosed apoptotic neutrophils, which was aided by IL-10. The lung neutrophil burden was attenuated in infected signal transducer and activator of transcription 1 (STAT1)(-/-) mice with concomitant increase in the frequency of the MDSC-like cells and lung IL-10 levels. Thus, inhibiting STAT1 in combination with antibiotics may be a novel therapeutic strategy to address inefficient resolution of bacterial pneumonia.

The term asthma encompasses a disease spectrum with mild to very severe disease phenotypes whose traditional common characteristic is reversible airflow limitation. Unlike milder disease, severe asthma is poorly controlled by the current standard of care. Ongoing studies using advanced molecular and immunological tools along with improved clinical classification show that severe asthma does not identify a specific patient phenotype, but rather includes patients with constant medical needs, whose pathobiologic and clinical characteristics vary widely. Accordingly, in recent clinical trials, therapies guided by specific patient characteristics have had better outcomes than previous therapies directed to any subject with a diagnosis of severe asthma. However, there are still significant gaps in our understanding of the full scope of this disease that hinder the development of effective treatments for all severe asthmatics. In this Review, we discuss our current state of knowledge regarding severe asthma, highlighting different molecular and immunological pathways that can be targeted for future therapeutic development.

Klebsiella pneumoniae remains an important cause of intrapulmonary infection and invasive disease worldwide. K. pneumoniae can evade serum killing and phagocytosis primarily through the expression of a polysaccharide capsule, but its pathogenicity is also influenced by host factors. We examined whether CD36, a scavenger receptor that recognizes pathogen and modified self ligands, is a host determinant of K. pneumoniae pathogenicity. Despite differences in serum sensitivity and virulence of 3 distinct K. pneumoniae (hypermucoviscous K1, research K2, and carbapenemase-producing ST258) strains, the absence of CD36 significantly increased host susceptibility to acute intrapulmonary infection by K. pneumoniae, regardless of strain. We demonstrate that CD36 enhances LPS responsiveness to K. pneumoniae to increase downstream cytokine production and macrophage phagocytosis that is independent of polysaccharide capsular antigen. Our study provides new insights into host determinants of K. pneumoniae pathogenicity and raises the possibility that functional mutations in CD36 may predispose individuals to K. pneumoniae syndromes.

Background Eosinophilic inflammation is implicated in asthma. Eotaxin 1–3 regulate eosinophil trafficking into the airways along with other chemotactic factors. However, the epithelial and bronchoalveolar lavage (BAL) cell expression of these chemokines in relation to asthma severity and eosinophilic phenotypes has not been addressed. Objective To measure the expression of the three eotaxin isoforms in bronchoscopically obtained samples and compare them with clinically relevant parameters between normal subjects and patients with asthma. Methods Normal subjects and patients with asthma of varying severity recruited through the Severe Asthma Research Program underwent clinical assessment and bronchoscopy with airway brushing and BAL. Eotaxin 1–3 mRNA/protein were measured in epithelial and BAL cells and compared with asthma severity, control and eosinophilic inflammation. Results Eotaxin-2 and eotaxin-3 mRNA and eotaxin-2 protein were increased in airway epithelial brushings from patients with asthma and were highest in cases of severe asthma (p values 0.0155, 0.0033 and 0.0006, respectively), with eotaxin-2 protein increased with age at onset. BAL cells normally expressed high levels of eotaxin-2 mRNA/protein but BAL fluid levels of eotaxin-2 were lowest in severe asthma. Epithelial eotaxin-2 and eotaxin-3 mRNA/protein was associated with sputum eosinophilia, lower forced expiratory volume in 1 s and more asthma exacerbations. Airway epithelial cell eotaxin-2 protein differed by asthma severity only in those with late onset disease, and tended to be highest in those with late onset eosinophilic asthma. Conclusions Epithelial eotaxin-2 and 3 are increased in asthma and severe asthma. Their expression may contribute to luminal migration of eosinophils, especially in later onset disease, asthma control and severity.

In humans, the bacterial product lipopolysaccharide (LPS) has been associated with protection from allergic diseases such as asthma. However, in mouse models of allergic asthma, differential effects of LPS have been noted based on the dose. A low dose of LPS promotes Th2 responses and allergic disease but a high dose has been associated with suppression of allergic airway inflammation. Our recent work has described the ability of LPS to increase the frequency of CD11b+Gr1intF4/80+ (abbreviated as Gr1int cells) cells in the lung tissue of mice in a dose-dependent fashion that is dependent on TLR4 and the TLR adaptor protein, MyD88. Both phenotypically and morphologically, the cells were found to have similarities with myeloid-derived suppressor cells. Adoptive transfer of LPS-induced Gr1int cells suppressed allergen-induced airway inflammation suggesting that these myeloid cells may have regulatory functions in allergic asthma. Although the Gr1int cells are readily detectable in the lung tissue of LPS-treated mice, they are barely detectable in the lung-draining lymph nodes (LNs) or in the airway lumen. This causes selective enrichment of these cells over dendritic cells (DCs) in the tissue since migratory DCs are induced by LPS to migrate to the draining LNs for presentation of antigen to LN T cells. The Gr1int cells were found to blunt the ability of lung DCs to upregulate GATA-3 or to promote STAT5 activation in primed Th2 cells, both transcription factors having critical roles in Th2 effector function. Thus, a complete understanding of the generation and regulation of the Gr1int cells would provide new avenues to either promote or delete these cells for disease-specific immunoregulation.

Myeloid-derived suppressor cells (MDSCs) have been investigated largely in the context of tumor progression. In contrast to the negative connotation of MDSCs in cancer immunity, our laboratory has recently reported on the development and role of pulmonary MDSC-like cells (CD11b(+)Gr1(int)F4/80(+)) in the regulation of allergic airway inflammation. These regulatory cells were expanded in a TLR4/MyD88-dependent manner and were both phenotypically and morphologically similar to those described in the tumor microenvironment. Although bacterial lipopolysaccharide (LPS) was initially described as an adjuvant in the development of allergic inflammation, subsequent studies showed that this is true only at relatively low doses of LPS. A high dose of LPS was shown to actually suppress eosinophilic airway inflammation. In our efforts to understand the mechanism underlying LPS-mediated suppression of allergic airway disease, we recently showed that LPS induces MDSC-like cells in the lung tissue in a dose-dependent manner, with increased accumulation of the cells at high doses of LPS. In contrast to lung dendritic cells (DCs), the MDSC-like cells did not traffic to the lung-draining lymph nodes, allowing them to act in a dominant fashion over DCs in the regulation of Th2 responses. The MDSC-like cells were found to blunt the ability of the lung DCs to upregulate GATA-3 or to promote STAT5 activation in primed Th2 cells, both transcription factors having critical roles in Th2 effector function. Thus, a complete understanding of the generation and regulation of the lung MDSCs would provide novel options for therapeutic interventions.