Moreover, several studies have reported SARS-CoV-2 organotropism in myocardial, renal, neural, and gastrointestinal tissues, confirming COVID-19 as a complex pathology with multiple manifestations. After virus entry, SARS-CoV-2 induces endothelial cell damage, complement activation, thrombin production, and fibrinolysis inhibition that result in pulmonary intravascular coagulation, vascular microthrombi formation, and, ultimately, severe vasculopathy, acute myocardial infarction, and stroke. Indeed, pathophysiological features of severe COVID-19 patients were often associated with pulmonary involvement that can require invasive mechanical ventilation in intensive care units (ICU). Īccumulating evidence suggests a close relationship between CRS and the pandemic of coronavirus disease 2019 (COVID-19) induced by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Patients with CRS frequently display respiratory symptoms including tachypnea that progress to acute respiratory distress syndrome (ARDS), severe kidney injury, hepatobiliary damage, cardiomyopathy, and neurological dysfunctions. This systemic pathology is not only associated with disseminated bacterial or viral infections but also induced by cancer immunotherapy, i.e., chimeric antigen receptor (CAR) T cells infusion or antibody-based therapy, stem cell transplantation settings, as well as linked to either autoimmune or genetic disorders. Under these circumstances, the increase in cytokines beyond the normal thresholds can cause a catastrophic cytokine storm known as cytokine release syndrome (CRS), which eventually leads to multiple organ failures. However, persistent infections or an uncontrolled microbial burden can prompt higher output of cytokines, which fuel emergency hematopoiesis to mobilize an increased number of leukocytes from the bone marrow and thus counterbalance the myeloid cell depletion in periphery. Since the magnitude of the immune response is generally consistent with the pathogen load and restrained to the invasion area, cytokines with short half-life have a limited action at sites of inflammation and favor the local activation of immune cells. Host responses to pathogens are ordered, time-dependent, and tissue-compartmentalized, coordinated by the release of soluble factors, such as growth factors and inflammatory cytokines, which engage, activate, and regulate innate immune cells. As STAT3-targeting approaches relieved inflammation, immune disorders, and organ failures in these mice, targeted intervention towards this pathway could suppress the lethal CRS inflammatory state. Indeed, constitutive expression of a viral FLIP homolog in myeloid cells triggered a STAT3-linked, progressive, and fatal inflammatory syndrome in mice, characterized by elevated cytokine output, lymphopenia, lung injury, and multiple organ dysfunctions that mimicked human CRS. FLIP controlled CRS by fueling a STAT3-dependent inflammatory program. We found that FLIP, a protein that controls caspase-8 death pathways, was highly expressed in myeloid cells of COVID-19 lungs. The underlying pathophysiology of CRS remains elusive. However, dysregulated anti-pathogen immune responses can provoke life-threatening inflammatory pathologies collectively known as cytokine release syndrome (CRS), exemplified by key clinical phenotypes unearthed during the SARS-CoV-2 pandemic. Inflammatory responses rapidly detect pathogen invasion and mount a regulated reaction. Fatal cytokine release syndrome by an aberrant FLIP/STAT3 axis
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |