Project description:We preformed a systems biological assessment of lower respiratory tract host immune responses and microbiome dynamics in COVD-19 patients, using bulk RNA-sequencing, single-cell RNA sequencing, and techniques, and microbiome analysis. Are focus was on differential gene expression in severe COVID-19 patients who developed ventilator associated pneumonia (VAP) during their course versus severe COVID-19 patients who did not develop VAP. We found early impairment in antibacterial immune signaling in patients two or more weeks prior to the development of VAP, compared to COVID-19 patients who did not develop VAP. There was no signficant difference in viral load, but an association of disruption in lung microbiome by alpha and beta diversity metrics was also found.
Project description:We preformed a systems biological assessment of lower respiratory tract host immune responses and microbiome dynamics in COVD-19 patients, using bulk RNA-sequencing, single-cell RNA sequencing, and techniques, and microbiome analysis. Are focus was on differential gene expression in severe COVID-19 patients who developed ventilator associated pneumonia (VAP) during their course versus severe COVID-19 patients who did not develop VAP. We found early impairment in antibacterial immune signaling in patients two or more weeks prior to the development of VAP, compared to COVID-19 patients who did not develop VAP. There was no signficant difference in viral load, but an association of disruption in lung microbiome by alpha and beta diversity metrics was also found.
Project description:Male sex belongs to one of the risk factors for severe COVID-19 outcome. However, underlying mechanisms that could affect sex dependent disease outcome are yet unknown. Here, we identified the CYP19A1 gene encoding for the testosterone-to-estradiol metabolizing enzyme CYP19A1 (alias aromatase) as a host factor that contributes to worsened disease outcome in male hamsters. SARS-CoV-2 infection increases CYP19A1 transcription most prominently in the lungs of male animals, which correlates with reduced circulating testosterone and increased circulating estradiol levels. Dysregulated sex hormone levels in male golden hamsters are associated with reduced lung function compared to females. Treatment of SARS-CoV-2 infected hamsters with letrozole, a clinically approved CYP19A1 inhibitor, supported recovery of dysregulated sex hormone levels and was associated with improved lung function in male but not female animals compared to placebo controls. Whole-lung transcriptome analysis in letrozole treated versus placebo treated control groups revealed key pathways associated with improved lung health in males. To seek translation of these findings into humans, we analyzed autopsy-derived lung samples of COVID-19 cases from three independent study sites. We found that CYP19A1 transcription and protein expression is strongly elevated in the lungs of men who died with COVID-19 as compared to females or non-COVID-19 controls. Our findings highlight the role of the lung as a yet unrecognized but critical organ involved in metabolic responses against respiratory virus infections. Furthermore, inhibition of CYP19A1 by the clinically approved drug letrozole may pose a new therapeutic strategy to reduce poor long-term COVID-19 outcome.
Project description:Respiratory failure and mortality from COVID-19 result from virus- and inflammation-induced lung tissue damage. The intestinal microbiome and associated metabolites are implicated in immune responses to respiratory viral infections, however their impact on progression of severe COVID-19 remains unclear. We prospectively enrolled 71 patients with COVID-19 associated critical illness, collected fecal specimens within 3 days of medical intensive care unit admission, defined microbiome compositions by shotgun metagenomic sequencing, and quantified microbiota-derived metabolites (NCT 04552834). Of the 71 patients, 39 survived and 32 died. Mortality was associated with increased representation of Proteobacteria in the fecal microbiota and decreased concentrations of fecal secondary bile acids and desaminotyrosine (DAT). A microbiome metabolic profile (MMP) that accounts for fecal secondary bile acids and desaminotyrosine concentrations was independently associated with progression of respiratory failure leading to mechanical ventilation. Our findings demonstrate that fecal microbiota composition and microbiota-derived metabolite concentrations can predict the trajectory of respiratory function and death in patients with severe SARS-Cov-2 infection and suggest that the gut-lung axis plays an important role in the recovery from COVID-19.
Project description:SARS-CoV-2, the virus responsible for COVID-19, causes widespread damage in the lungs in the setting of an overzealous immune response whose origin remains unclear. We present a scalable, propagable, personalized, cost-effective adult stem cell-derived human lung organoid model that is complete with both proximal and distal airway epithelia. Monolayers derived from adult lung organoids (ALOs), primary airway cells, or hiPSC-derived alveolar type-II (AT2) pneumocytes were infected with SARS-CoV-2 to create in vitro lung models of COVID-19. Infected ALO-monolayers best recapitulated the transcriptomic signatures in diverse cohorts of COVID-19 patient-derived respiratory samples. The airway (proximal) cells were critical for sustained viral infection, whereas distal alveolar differentiation (AT2→AT1) was critical for mounting the overzealous host immune response in fatal disease; ALO monolayers with well-mixed proximodistal airway components recapitulated both. Findings validate a human lung model of COVID-19 , which can be immediately utilized to investigate COVID-19 pathogenesis and vet new therapies and vaccines.
Project description:While critical for host defense, innate immune cells are also pathologic drivers of acute respiratory distress syndrome (ARDS). Innate immune dynamics during COVID-19 ARDS, compared to ARDS from other respiratory pathogens, is unclear. Moreover, mechanisms underlying beneficial effects of dexamethasone during severe COVID-19 remain elusive. Using scRNA-seq and plasma proteomics, we discovered that compared to bacterial ARDS, COVID-19 was associated with expansion of distinct neutrophil states characterized by interferon (IFN) and prostaglandin (PG) signalling. Dexamethasone during severe COVID-19 depleted circulating neutrophils, altered IFNactive neutrophils, downregulated interferon-stimulated gene, and activated IL1R2+ve neutrophils. Dexamethasone also expanded immunosuppressive immature neutrophils and remodeled cellular interactions by changing neutrophils from information receivers into information providers. Male patients had higher proportions of IFNactive neutrophils, preferential steroid-induced immature neutrophil expansion, and possibly different effects on outcome. Our single-cell atlas (www.biernaskielab.ca/COVID_neutrophil) defines COVID-19-enriched neutrophil states and molecular mechanisms of dexamethasone action to develop targeted immunotherapies for severe COVID-19.
Project description:Severe COVID-19 may progress into acute respiratory distress syndrome (ARDS) with high mortality risk. Its exact pathological mechanism, therapeutic obstacles and the clinical sequelae are critical and unresolved issues. Here, we reported a representative COVID-19 induced ARDS case experienced initially stable, then suddenly deteriorating up to final respiratory failure courses, until his death despite of lung transplantation. His lung pathology showed necrosis of parenchymal tissues, extensive immune cell infiltration and lung fibrosis. Single-cell RNA sequencing revealed various immune cell populations were largely expanded in his lung, and manifested inflammatory/activated functions. We also showed that cell-crosstalk between lung macrophages and fibroblasts promoted pulmonary fibrosis through IL-1B and TGF-Β signaling pathways. Although SARS-CoV-2 RNA remained undetectable in his respiratory tract specimens including BALF at the later stage of his disease, the presence of SARS-CoV-2 was definitely confirmed in his lung tissues. Thus, this case indicates the pathological mechanism of severe COVID-19 includes pulmonary SARS-CoV-2 persistence, deranged inflammation and the extensive lung fibrosis which set the barriers for effective treatments and indicate potential health complications for severe COVID-19 patients.
Project description:High throughput sequencing is performed on mRNA isolated from whole blood of adult Covid-19 patients, bacterial coinfection with Covid-19 and healthy controls in a South Indian cohort. Samples were collected from individuals at the time of hospitalization or visit to clinic. The Covid-19 samples are categorized by severeity.
Project description:Although a substantial proportion of severe COVID-19 pneumonia survivors exhibit long-term pulmonary sequalae, the underlying mechanisms or associated local and systemic immune correlates are not known. Here, we have performed high dimensional characterization of the pathophysiological and immune traits of aged COVID-19 convalescents, and correlated the local and systemic immune profiles with pulmonary function and lung imaging. In this cohort of aged COVID-19 convalescents, chronic lung impairment was accompanied by persistent systemic inflammation and respiratory immune alterations. Detailed evaluation of the lung immune compartment revealed dysregulated respiratory CD8+ T cell responses that likely underlie the impaired lung function following acute COVID-19 during aging. Single cell transcriptomic analysis identified the potential pathogenic subsets of respiratory CD8+ T cells causing persistent tissue conditions following COVID-19. Our results have revealed key pathophysiological and immune traits that support the development of lung sequelae following SARS-CoV2 pneumonia during aging, with implications for the treatment of chronic COVID-19 symptoms.