Project description:Background: COVID-19 and sepsis represent formidable public health challenges, characterized by incompletely elucidated molecular mechanisms. Elucidating the interplay between COVID-19 and sepsis, particularly in geriatric patients suffering from sepsis-induced acute respiratory distress syndrome (ARDS), is of paramount importance for identifying potential therapeutic interventions to mitigate hospitalization and mortality risks.We employed bioinformatics and systems biology approaches to identify hub genes, shared pathways, molecular biomarkers, and candidate therapeutics for managing COVID-19, sepsis, and sepsis-induced ARDS. We corroborated these hub genes utilizing murine sepsis-ARDS models and blood samples derived from geriatric patients afflicted by sepsis-induced ARDS.Results: Our investigation revealed 189 differentially expressed genes (DEGs) shared among COVID-19 and sepsis datasets. We constructed a protein-protein interaction network, unearthing pivotal hub genes and modules. Notably, nine hub genes displayed significant alterations and correlations with critical inflammatory mediators of pulmonary injury in murine septic lungs. Simultaneously, 12 displayed significant changes and correlations with a neutrophil-recruiting chemokine in geriatric patients with sepsis-induced ARDS. Of these, six hub genes (CD247, CD2, CD40LG, KLRB1, LCN2, RETN) showed significant alterations across COVID-19, sepsis, and geriatric sepsis-induced ARDS. Our single-cell RNA sequencing analysis of hub genes across 3 diverse immune cell types furnished insights into disease pathogenesis. Functional analysis underscored the interconnection between sepsis/sepsis-ARDS and COVID-19, enabling us to pinpoint potential therapeutic targets, transcription factor-gene interactions, DEG-microRNA co-regulatory networks, and prospective drug and chemical compound interactions involving hub genes.Our investigation offers potential therapeutic targets/biomarkers, sheds light on the immune response in geriatric patients with sepsis-induced ARDS, emphasizes the association between sepsis/sepsis-ARDS and COVID-19, and proposes novel avenues for targeted therapies.
Project description:Clinical study of critically ill patients with sepsis and sepsis-related ARDS with whole blood RNA collected within the first 24 hours of admission Goal of the study was to determine whether biologically relevant genes were identified to be differentially expressed genes in patients with sepsis alone and sepsis with ARDS Prospective observational study, case cohort design
Project description:Clinical study of critically ill patients with sepsis and sepsis-related ARDS with whole blood RNA collected within the first 24 hours of admission Goal of the study was to determine whether biologically relevant genes were identified to be differentially expressed genes in patients with sepsis alone and sepsis with ARDS
Project description:The acute respiratory distress syndrome (ARDS) results from overwhelming pulmonary inflammation. We used single cell RNA sequencing to probe ARDS at a higher resolution for insights into ARDS pathogenesis. Peripheral blood mononuclear cells of patients with pneumonia and sepsis with early ARDS were compared to that of sepsis patients who did not develop ARDS. Monocyte clusters from ARDS patients revealed multiple distinguishing characteristics in comparison to monocytes from patients without ARDS including down-regulation of SOCS3 expression accompanied by a pro-inflammatory signature with up-regulation of multiple type I IFN-induced genes, especially in CD16+ cells. These data show that monocytes of ARDS patients up-regulate 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.
Project description:Acute Lung Injury (ALI) can cause Acute Respiratory Distress Syndrome (ARDS), a lethal condition with limited treatment options and currently a common global cause of death due to COVID-19-induced ALI. ARDS secondary to Transfusion-Related Acute Lung Injury (TRALI) has been recapitulated pre-clinically by anti-MHC-I antibody administration to LPS-primed mice. In this model, we demonstrated that inhibitors of PTP1B, a protein tyrosine phosphatase that regulates signaling pathways of fundamental importance to homeostasis and inflammation, prevented lung injury and increased survival. Treatment with PTP1B inhibitors attenuated the aberrant neutrophil function that drives ALI, and was associated with release of myeloperoxidase, suppression of Neutrophil Extracellular Trap (NET) formation, and inhibition of neutrophil migration. Mechanistically, reduced signaling through the CXCR4 chemokine receptor, particularly to the activation of mTOR, was essential for these effects, linking PTP1B in hibition to promoting an aged neutrophil phenotype. Considering dysregulated activation of neutrophils is implicated in sepsis and can cause collateral tissue damage, we demonstrated also that PTP1B inhibitors improved survival and ameliorated lung injury in the LPS-induced sepsis model. Our data highlight PTP1B inhibition for prevention of TRALI and ARDS from multiple etiologies.
Project description:SARS-CoV-2 is a novel coronavirus that causes acute respiratory distress syndrome (ARDS), death and long-term sequelae. Innate immune cells are critical for host defense but are also the primary drivers of ARDS. The relationships between innate cellular responses in ARDS resulting from COVID-19 compared to other causes of ARDS, such as bacterial sepsis is unclear. Moreover, the beneficial effects of dexamethasone therapy during severe COVID-19 remain speculative, but understanding the mechanistic effects could improve evidence-based therapeutic interventions. To interrogate these relationships, we developed an scRNAseq atlas that is freely accessible (biernaskielab.ca/COVID_neutrophil). We discovered that compared to bacterial ARDS, COVID-19 was associated with distinct neutrophil polarization characterized by either interferon (IFN) or prostaglandin (PG) active states. Neutrophils from bacterial ARDS had higher expression of antibacterial molecules such as PLAC8 and CD83. Dexamethasone therapy in COVID patients rapidly altered the IFNactive state, downregulated interferon responsive genes, and activated IL1R2+ve neutrophils. Dexamethasone also induced the emergence of immature neutrophils expressing immunosuppressive molecules ARG1 and ANXA1, which were not present in healthy controls. Moreover, dexamethasone remodeled global cellular interactions by changing neutrophils from information receivers into information providers. Importantly, male patients had higher proportions of IFNactive neutrophils and a greater degree of steroid-induced immature neutrophil expansion. Indeed, the highest proportion of IFNactive neutrophils was associated with mortality. These results define neutrophil states unique to COVID-19 when contextualized to other life-threatening infections, thereby enhancing the relevance of our findings at the bedside. Furthermore, the molecular benefits of dexamethasone therapy are also defined. The identified molecular pathways can now be targeted to develop improved therapeutics.
Project description:A microarray analysis involving whole blood samples isolated from critically ill patients in the medical intensive care unit at Brigham and Women's Hospital. Four groups of intubated subjects undergoing mechanical ventilation were recruited for the study: those with sepsis alone (Sepsis), those with sepsis + ARDS (se/ARDS), those with SIRS (SIRS), and those whithout sepsis, SIRS, or ARDS (untreated). Blood was obtained from patients on the day of admission (day 0) and 7 days later. RNA was isolated from the whole blood samples and microarrays were prepared to determine differential gene expression between the four groups. Total RNA obtained from whole blood samples of critically ill patients
Project description:Both sepsis and acute respiratory distress syndrome (ARDS) rely on imprecise clinical definitions leading to heterogeneity, which has contributed to negative trials. Because circulating protein/DNA complexes have been implicated in sepsis and ARDS, we aimed to develop a proteomic signature of DNA-bound proteins to discriminate between children with sepsis with and without ARDS. We performed a prospective case-control study in 12 children with sepsis with ARDS matched to 12 children with sepsis without ARDS on age, severity of illness score, and source of infection. We performed co-immunoprecipitation and downstream proteomics in plasma collected ≤ 24 h of intensive care unit admission. Expression profiles were generated, and a random forest classifier was used on differentially expressed proteins to develop a signature which discriminated ARDS. The classifier was tested in six independent blinded samples. Neutrophil and nucleosome proteins were over-represented in ARDS, including two S100A proteins, superoxide dismutase (SOD), and three histones. Random forest produced a 10-protein signature that accurately discriminated between children with sepsis with and without ARDS. This classifier perfectly assigned six independent blinded samples as having ARDS or not. We validated higher expression of the most informative discriminating protein, galectin-3-binding protein, in children with ARDS. Our methodology has applicability to isolation of DNA-bound proteins from plasma. Our results support the premise of a molecular definition of ARDS, and give preliminary insight into why some children with sepsis, but not others, develop ARDS.
Project description:Acute respiratory distress syndrome (ARDS) is a severe critical condition with a high mortality that is currently in focus given that it is associated with mortality caused by coronavirus induced disease 2019 (COVID-19). Neutrophils play a key role in the lung injury characteristic of non-COVID-19 ARDS and there is also accumulating evidence of neutrophil mediated lung injury in patients who succumb to infection with SARS-CoV-2. We undertook a functional proteomic and metabolomic survey of circulating neutrophil populations, comparing patients with COVID-19 ARDS and non-COVID-19 ARDS to understand the molecular basis of neutrophil dysregulation. Expansion of the circulating neutrophil compartment and the presence of activated low and normal density mature and immature neutrophil populations occurs in ARDS, irrespective of cause. Release of neutrophil granule proteins, neutrophil activation of the clotting cascade and upregulation of the Mac-1 platelet binding complex with formation of neutrophil platelet aggregates is exaggerated in COVID-19 ARDS. Importantly, activation of components of the neutrophil type I interferon responses is seen in ARDS following infection with SARS-CoV-2, with associated rewiring of neutrophil metabolism to promote glutamine utilisation, and the upregulation of antigen processing and presentation. Whilst dexamethasone treatment constricts the immature low density neutrophil population it does not impact upon prothrombotic hyperinflammatory neutrophil signatures.