Project description:Mice with a human immune system (humanized mice), generated by transplantation of human hematopoietic stem and progenitor cells (HSPCs), serve as invaluable tools to study the development and function of the human immune system in vivo. MISTRG6 mouse model, engineered by a human/mouse homolog gene-replacement strategy, provides physiological factors for essentially all classes of human HSPCs to develop in mice. MISTRG6 (acronym for genes replaced) mice encode humanized M-CSF (enabling monocytes and tissue macrophage development), GM-CSF/IL-3 (to provide lung alveolar macrophages), SIRPa (establish macrophage tolerance to human cells), ThPO (hematopoiesis and platelets), and IL-6 (better engraftment allowing study of adult human patients and improved antigen-specific antibody responses as well as human IL-6 per se), in a Rag2/Gamma common chain deleted background. By adapting recombinant adeno-associated virus (AAV)-driven gene therapy to deliver hACE2 to the lungs, which allows infection with SARS-CoV-2 of MISTRG6 mice engrafted with HPSCs, we created a humanized mouse model of COVID-19 that recapitulates the distribution and function of the human innate and adaptive immune system and is amenable to the mechanistic study of COVID-19 and its myriad of complications. We evaluated the lung transcriptional landscape and response to therapeutics in this model. First, we assessed the impact of anti-IFNAR2 and Remdesivir combined therapy and control dexamethasone therapy on the immunological transcriptome of SARS-CoV-2 infected MISTRG6-hACE2 mice by focusing on differentially regulated human genes in whole lung tissue. We treated infected MISTRG6-hACE2 mice with Remdesivir, anti-IFNAR2 antibody or a combination of the two starting 7dpi, to sequentially target viral replication and the IFN-dependent cascade downstream of infection. As a control, we also treated mice with dexamethasone, one of the few treatments that significantly reduced hospitalization and mortality in the clinic. Next, we compared the single cell transcriptomes of human immune cells from infected mice late in disease (28dpi) with their uninfected counterparts to gain a deeper understanding of transcriptional changes at the cellular level. Finally, we focused our efforts on deeper characterization of monocyte/macrophage clusters at early (4dpi) or late (14 and 28dpi) infection.
Project description:Mice with a human immune system (humanized mice), generated by transplantation of human hematopoietic stem and progenitor cells (HSPCs), serve as invaluable tools to study the development and function of the human immune system in vivo. MISTRG6 mouse model, engineered by a human/mouse homolog gene-replacement strategy, provides physiological factors for essentially all classes of human HSPCs to develop in mice. MISTRG6 (acronym for genes replaced) mice encode humanized M-CSF (enabling monocytes and tissue macrophage development), GM-CSF/IL-3 (to provide lung alveolar macrophages), SIRPa (establish macrophage tolerance to human cells), ThPO (hematopoiesis and platelets), and IL-6 (better engraftment allowing study of adult human patients and improved antigen-specific antibody responses as well as human IL-6 per se), in a Rag2/Gamma common chain deleted background. By adapting recombinant adeno-associated virus (AAV)-driven gene therapy to deliver hACE2 to the lungs, which allows infection with SARS-CoV-2 of MISTRG6 mice engrafted with HPSCs, we created a humanized mouse model of COVID-19 that recapitulates the distribution and function of the human innate and adaptive immune system and is amenable to the mechanistic study of COVID-19 and its myriad of complications. We evaluated the lung transcriptional landscape and response to therapeutics in this model. First, we assessed the impact of anti-IFNAR2 and Remdesivir combined therapy and control dexamethasone therapy on the immunological transcriptome of SARS-CoV-2 infected MISTRG6-hACE2 mice by focusing on differentially regulated human genes in whole lung tissue. We treated infected MISTRG6-hACE2 mice with Remdesivir, anti-IFNAR2 antibody or a combination of the two starting 7dpi, to sequentially target viral replication and the IFN-dependent cascade downstream of infection. As a control, we also treated mice with dexamethasone, one of the few treatments that significantly reduced hospitalization and mortality in the clinic. Next, we compared the single cell transcriptomes of human immune cells from infected mice late in disease (28dpi) with their uninfected counterparts to gain a deeper understanding of transcriptional changes at the cellular level. Finally, we focused our efforts on deeper characterization of monocyte/macrophage clusters at early (4dpi) or late (14 and 28dpi) infection.
Project description:Mice with a human immune system (humanized mice), generated by transplantation of human hematopoietic stem and progenitor cells (HSPCs), serve as invaluable tools to study the development and function of the human immune system in vivo. By adapting recombinant adeno-associated virus (AAV)-driven gene therapy to deliver hACE2 to the lungs, which allows infection with SARS-CoV-2 of MISTRG6 mice engrafted with HPSCs, we created a humanized mouse model of COVID-19 that recapitulates the distribution and function of the human innate and adaptive immune system and is amenable to the mechanistic study of COVID-19 and its myriad of complications. MISTRG6 mouse model was engineered by a human/mouse homolog gene-replacement strategy to provide physiological factors with regard to quantity, location and time and enable essentially all classes of human HSPCs to develop in mice. MISTRG6 (acronym for genes replaced) mice encode humanized M-CSF (enabling monocytes and tissue macrophage development), GM-CSF/IL-3 (to provide lung alveolar macrophages), SIRPa (establish macrophage tolerance to human cells), ThPO (hematopoiesis and platelets), and IL-6 (better engraftment allowing study of adult human patients and improved antigen-specific antibody responses as well as human IL-6 per se), in a Rag2/Gamma common chain deleted background. We evaluated the transcriptional landscape in uninfected and SARS-CoV-2 infected lungs of humanized mice at multiple time points (2, 4, 7, 14, 28 dpi).
Project description:Immune responses in lungs of Coronavirus Disease 2019 (COVID-19) are poorly characterized. We conducted transcriptomic, histologic and cellular profiling of post mortem COVID-19 and normal lung tissues. Two distinct immunopathological reaction patterns were identified. One pattern showed high expression of interferon stimulated genes (ISGs) and cytokines, high viral loads and limited pulmonary damage, the other pattern showed severely damaged lungs, low ISGs, low viral loads and abundant immune infiltrates. Distinct patterns of pulmonary COVID-19 immune responses correlated to hospitalization time and may guide treatment and vaccination approaches.
Project description:Here we analyze the transcriptional profiles of homogenized lungs resected from APOE2, APOE3, and APOE4 knock-in mice on day 4 post infection with SARS-CoV-2 MA10. This experiment validated a prior RNA-seq experiment revealing blunted adaptive immunity in APOE2 and APOE4 mice during COVID-19 progression.
Project description:Life-threatening thrombotic events and neurological symptoms are prevalent in COVID-19 and are persistent in patients with long COVID experiencing post-acute sequelae of SARS-CoV-2 infection1,2,3,4. Despite the clinical evidence1,5,6,7, the underlying mechanisms of coagulopathy in COVID-19 and its consequences in inflammation and neuropathology remain poorly understood and treatment options are insufficient. Fibrinogen, the central structural component of blood clots, is abundantly deposited in the lungs and brains of patients with COVID-19, correlates with disease severity and is a predictive biomarker for post-COVID-19 cognitive deficits1,5,8,9,10. Here we show that fibrin binds to the SARS-CoV-2 spike protein, forming proinflammatory blood clots that drive systemic thromboinflammation and neuropathology in COVID-19. Fibrin, acting through its inflammatory domain, is required for oxidative stress and macrophage activation in the lungs, whereas it suppresses natural killer cells, after SARS-CoV-2 infection. Fibrin promotes neuroinflammation and neuronal loss after infection, as well as innate immune activation in the brain and lungs independently of active infection. A monoclonal antibody targeting the inflammatory fibrin domain provides protection from microglial activation and neuronal injury, as well as from thromboinflammation in the lung after infection. Thus, fibrin drives inflammation and neuropathology in SARS-CoV-2 infection, and fibrin-targeting immunotherapy may represent a therapeutic intervention for patients with acute COVID-19 and long COVID.
Project description:Life-threatening thrombotic events and neurological symptoms are prevalent in COVID-19 and are persistent in patients with long COVID experiencing post-acute sequelae of SARS-CoV-2 infection1,2,3,4. Despite the clinical evidence1,5,6,7, the underlying mechanisms of coagulopathy in COVID-19 and its consequences in inflammation and neuropathology remain poorly understood and treatment options are insufficient. Fibrinogen, the central structural component of blood clots, is abundantly deposited in the lungs and brains of patients with COVID-19, correlates with disease severity and is a predictive biomarker for post-COVID-19 cognitive deficits1,5,8,9,10. Here we show that fibrin binds to the SARS-CoV-2 spike protein, forming proinflammatory blood clots that drive systemic thromboinflammation and neuropathology in COVID-19. Fibrin, acting through its inflammatory domain, is required for oxidative stress and macrophage activation in the lungs, whereas it suppresses natural killer cells, after SARS-CoV-2 infection. Fibrin promotes neuroinflammation and neuronal loss after infection, as well as innate immune activation in the brain and lungs independently of active infection. A monoclonal antibody targeting the inflammatory fibrin domain provides protection from microglial activation and neuronal injury, as well as from thromboinflammation in the lung after infection. Thus, fibrin drives inflammation and neuropathology in SARS-CoV-2 infection, and fibrin-targeting immunotherapy may represent a therapeutic intervention for patients with acute COVID-19 and long COVID.
Project description:Post-acute sequelae of COVID-19 (PASC) represent an emerging global crisis. However, quantifiable risk-factors for PASC and their biological associations are poorly resolved. We executed a deep multi-omic, longitudinal investigation of 309 COVID-19 patients from initial diagnosis to convalescence (2-3 months later), integrated with clinical data, and patient-reported symptoms. We resolved four PASC-anticipating risk factors at the time of initial COVID-19 diagnosis: type 2 diabetes, SARS-CoV-2 RNAemia, Epstein-Barr virus viremia, and specific autoantibodies. In patients with gastrointestinal PASC, SARS-CoV-2-specific and CMV-specific CD8+ T cells exhibited unique dynamics during recovery from COVID-19. Analysis of symptom-associated immunological signatures revealed coordinated immunity polarization into four endotypes exhibiting divergent acute severity and PASC. We find that immunological associations between PASC factors diminish over time leading to distinct convalescent immune states. Detectability of most PASC factors at COVID-19 diagnosis emphasizes the importance of early disease measurements for understanding emergent chronic conditions and suggests PASC treatment strategies.