RESUMO
The release of neutrophil extracellular traps (NETs) is associated with inflammation, coagulopathy, and organ damage found in severe cases of COVID-19. However, the molecular mechanisms underlying the release of NETs in COVID-19 remain unclear. Using a single-cell transcriptome analysis we observed that the expression of GSDMD and inflammasome-related genes were increased in neutrophils from COVID-19 patients. Furthermore, high expression of GSDMD was found associated with NETs structures in the lung tissue of COVID-19 patients. The activation of GSDMD in neutrophils requires live SARS-CoV-2 and occurs after neutrophil infection via ACE2 receptors and serine protease TMPRSS2. In a mouse model of SARS-CoV-2 infection, the treatment with GSDMD inhibitor (disulfiram) reduced NETs release and organ damage. These results demonstrated that GSDMD-dependent NETosis plays a critical role in COVID-19 immunopathology, and suggests that GSDMD inhibitors, can be useful to COVID-19 treatment. In BriefHere, we showed that the activation of the Gasdermin-D (GSDMD) pathway in neutrophils controls NET release during COVID-19. The inhibition of GSDMD with disulfiram, abrogated NET formation reducing lung inflammation and tissue damage. These findings suggest GSDMD as a target for improving the COVID-19 therapy.
RESUMO
Although increasing evidence confirms neuropsychiatric manifestations associated mainly with severe COVID-19 infection, the long-term neuropsychiatric dysfunction has been frequently observed after mild infection. Here we show the spectrum of the cerebral impact of SARS-CoV-2 infection ranging from long-term alterations in mildly infected individuals (orbitofrontal cortical atrophy, neurocognitive impairment, excessive fatigue and anxiety symptoms) to severe acute damage confirmed in brain tissue samples extracted from the orbitofrontal region (via endonasal trans-ethmoidal approach) from individuals who died of COVID-19. We used surface-based analyses of 3T MRI and identified orbitofrontal cortical atrophy in a group of 81 mildly infected patients (77% referred anosmia or dysgeusia during acute stage) compared to 145 healthy volunteers; this atrophy correlated with symptoms of anxiety and cognitive dysfunction. In an independent cohort of 26 individuals who died of COVID-19, we used histopathological signs of brain damage as a guide for possible SARS-CoV-2 brain infection, and found that among the 5 individuals who exhibited those signs, all of them had genetic material of the virus in the brain. Brain tissue samples from these 5 patients also exhibited foci of SARS-CoV-2 infection and replication, particularly in astrocytes. Supporting the hypothesis of astrocyte infection, neural stem cell-derived human astrocytes in vitro are susceptible to SARS-CoV-2 infection through a non-canonical mechanism that involves spike-NRP1 interaction. SARS-CoV-2-infected astrocytes manifested changes in energy metabolism and in key proteins and metabolites used to fuel neurons, as well as in the biogenesis of neurotransmitters. Moreover, human astrocyte infection elicits a secretory phenotype that reduces neuronal viability. Our data support the model in which SARS-CoV-2 reaches the brain, infects astrocytes and consequently leads to neuronal death or dysfunction. These deregulated processes are also likely to contribute to the structural and functional alterations seen in the brains of COVID-19 patients.
