Neutrophil virucidal activity against SARS-CoV-2 is mediated by NETs.

BACKGROUND: The inflammation in the lungs and other vital organs in COVID-19 are characterized by the presence of neutrophils and high concentration of neutrophil extracellular traps (NETs), which also seems to mediate host tissue damage. However, it is not known whether NETs could have virucidal activity against SARS-CoV-2. METHODS: We investigated whether NETs could prevent SARS-CoV-2 replication in neutrophils and epithelial cells, and what the consequence of NETs degradation in K18-humanized ACE2 transgenic mice infected with SARS-CoV-2. RESULTS: Here, by immunofluorescence microscopy we observed that viral particles co-localize with NETs in neutrophils isolated from COVID-19 patients or from healthy individuals and infected in vitro. The inhibition of NETs production increased virus replication in neutrophils. In parallel, we observed that NETs inhibited virus abilities to infect and replicate in epithelial cells after 24 h of infection. Degradation of NETs with DNase I prevented their virucidal effect in vitro. Using K18-humanized ACE2 transgenic mice we observed a higher viral load in animals treated with DNase I. On the other hand, the virucidal effect of NETs was not dependent on neutrophil elastase or myeloperoxidase activity. CONCLUSION: Our results provide evidence of the role of NETosis as a mechanism of SARS-CoV-2 viral capture and inhibition.

Morphological, cellular, and molecular basis of brain infection in COVID-19 patients.

Although increasing evidence confirms neuropsychiatric manifestations associated mainly with severe COVID-19 infection, long-term neuropsychiatric dysfunction (recently characterized as part of "long COVID-19" syndrome) has been frequently observed after mild infection. We show the spectrum of cerebral impact of severe acute respiratory syndrome coronavirus 2 (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 transethmoidal access) from individuals who died of COVID-19. 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 five 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 noncanonical 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 could contribute to the structural and functional alterations seen in the brains of COVID-19 patients.

Gasdermin-D activation by SARS-CoV-2 triggers NET and mediate COVID-19 immunopathology.

BACKGROUND: 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. OBJECTIVES: We aim to investigate the role of the Gasdermin-D (GSDMD) pathway on NETs release and the development of organ damage during COVID-19. METHODS: We performed a single-cell transcriptome analysis in public data of bronchoalveolar lavage. Then, we enrolled 63 hospitalized patients with moderate and severe COVID-19. We analyze in blood and lung tissue samples the expression of GSDMD, presence of NETs, and signaling pathways upstreaming. Furthermore, we analyzed the treatment with disulfiram in a mouse model of SARS-CoV-2 infection. RESULTS: We found that the SARS-CoV-2 virus directly activates the pore-forming protein GSDMD that triggers NET production and organ damage in COVID-19. Single-cell transcriptome analysis revealed that the expression of GSDMD and inflammasome-related genes were increased in COVID-19 patients. High expression of active GSDMD associated with NETs structures was found in the lung tissue of COVID-19 patients. Furthermore, we showed that activation of GSDMD in neutrophils requires active caspase1/4 and live SARS-CoV-2, which infects neutrophils. In a mouse model of SARS-CoV-2 infection, the treatment with disulfiram inhibited NETs release and reduced organ damage. CONCLUSION: These results demonstrated that GSDMD-dependent NETosis plays a critical role in COVID-19 immunopathology and suggests GSDMD as a novel potential target for improving the COVID-19 therapeutic strategy.

Lack of Association of Polymorphisms in IL22 and IL22RA1 Genes with Fibrosis Severity in Patients with Chronic Hepatitis C.

The IL-22 pathway has been shown to play an important role in the pathogenesis of liver fibrosis. However, little is known about the role of single-nucleotide polymorphisms (SNPs) in IL-22-related genes in relation to the severity of liver fibrosis. This study aimed to investigate the association of polymorphisms in IL22 and IL22RA1 genes with the severity of liver fibrosis in patients with chronic hepatitis C. A total of 326 patients (165 with mild fibrosis and 161 with severe fibrosis) were included. Four SNPs in IL22 (rs1179251, rs2227473, rs1012356, and rs2227485) and two in IL22RA1 (rs4648936 and rs3795299) were evaluated by real-time PCR. No significant association was observed between the polymorphisms studied and the severity of liver fibrosis. The SNPs rs1179251, rs2227473, rs1012356, and rs2227485 in IL22 and rs4648936 and rs3795299 in IL22RA1 may not be involved in the pathogenesis of liver fibrosis in patients with chronic hepatitis C.

Liver expression of IL-22, IL-22R1 and IL-22BP in patients with chronic hepatitis C with different fibrosis stages.

AIMS: Liver fibrosis is the result of an exacerbated wound-healing response associated with chronic liver injury. Interleukin-22 (IL-22) plays a key role in liver disease, through either a protective or an adverse role, depending on the context. The relationship between IL-22 and its receptors IL-22R1 and IL-22BP (soluble inhibitor) in liver fibrosis is unknown. In this study, we assessed the presence and quantity of IL-22, IL-22R1, and IL-22BP-producing cells in liver tissues of patients with chronic hepatitis C. METHODS AND RESULTS: The number of IL-22-producing cells was significantly higher in stages F1, F2, and F3 when compared to F0 or F4 (p < 0.05). The immunostaining of IL-22R1 decreased as liver fibrosis increased from F1 to F4. On the other hand, the concentration of IL-22BP-producing cells was higher in patients with cirrhosis (F4). Furthermore, the IL-22BP:IL-22 ratio was highest in patients with cirrhosis. CONCLUSIONS: Our results suggest that IL-22, IL-22R1 and IL-22BP may be involved in the mechanisms of liver fibrosis in patients with chronic hepatitis C.

Perfil bacteriano das superfícies e equipamentos da Clínica Ortopédica de um Hospital Universitário / Bacterial profile of surfaces and equipment of the Orthopedic Clinic of a University Hospital / Perfil bacteriano de las superficies y equipos de la Clínica Ortopédica de un Hospital Universitario

Justificativa e Objetivos: As Infecções Relacionadas a Assistência à Saúde (IRAS) são um importante problema de saúde pública que causa impactos negativos nos custos hospitalares e prognóstico dos pacientes. Diante da importância do ambiente hospitalar no desenvolvimento das IRAS, objetiva-se avaliar o perfil bacteriano em superfícies e equipamentos da Clínica Ortopédica do Hospital Universitário do Vale do São Francisco. Métodos: Trata-se de um estudo transversal e descritivo de natureza quantitativa. As amostras foram coletadas em 13 enfermarias, onde foram amostrados superfícies e equipamentos dos leitos e das enfermarias, utilizando-se swabs embebidos em solução salina e um molde de papel filtro de área de 1cm2 a fim de padronizar as amostras. Após a passagem do swab, os mesmos foram armazenados em tubo contendo 5mL de meio líquido BHI (Brain Heart Infusion). Em seguida, as amostras foram transportadas para o Laboratório de Análises Clínicas/Setor Microbiologia, onde foram realizadas as análises microbiológicas. Resultados: Observou-se um total de 257 bactérias, sendo 5,11% possíveis causadoras de infecção hospitalar e 79% Staphylococcus coagulase negativa, as quais foram submetidas aos antibiogramas e mostraram diferentes perfis de resistência. A maçaneta do banheiro, uma superfície de alto toque, apresentou a maior variedade de espécies entre as superfícies avaliadas. Conclusão: Superfícies e equipamentos da clínica avaliada apresentam bactérias possíveis causadoras de infecção hospitalar com diferentes perfis de resistência antimicrobiana, contribuindo para possíveis infecções cruzadas.(AU)

Justificación y Objetivos: Las infecciones asociadas a la asistencia sanitaria (IAAS) son un importante problema de salud pública que impacta negativamente en los costos hospitalarios y el pronóstico de los pacientes. Dada la importancia del entorno hospitalario en el desarrollo de las IAAS, el objetivo fue evaluar el perfil bacteriano en superficies y equipos de la Clínica Ortopédica del Hospital Universitário do Vale do São Francisco. Métodos: Se trata de un estudio transversal, descriptivo y cuantitativo. Las muestras se recolectaron en 13 salas, cada sala con cuatro camas y una se eligió al azar, donde se muestrearon las superficies y el equipo utilizando hisopos empapados en solución salina y un molde de papel de filtro de 1cm2 para estandarizar las muestras. Después de pasar el hisopo, se almacenaron en un tubo que contenía 5 ml de medio líquido BHI (infusión cerebro corazón). Luego, las muestras fueron transportadas al Laboratorio de Análisis Clínicos/Sector de Microbiología, donde se realizaron los análisis microbiológicos. Resultados: Se observó un total de 257 bacterias, de las cuales el 5,11% fueron posibles causas de infección hospitalaria y el 79% Staphylococcus coagulasa negativo. Se realizaron antibiogramas de estos y se encontraron diferentes perfiles de resistencia. La manija del baño, una superficie de alto tacto, presentó la mayor variedad de especies entre las superficies evaluadas. Conclusiones: Las superficies y el equipo de la clínica evaluada presentan posibles bacterias que causan infección hospitalaria con diferentes perfiles de resistencia a los antimicrobianos, lo que contribuye a posibles infecciones cruzadas.(AU)

Background and Objectives: Healthcare-Associated Infections (HAIs) are an important public health problem that impacts negatively on hospital costs and patient prognosis. Given the importance of the hospital environment in the development of HAIs, the objective was to evaluate the bacterial profile on surfaces and equipment of the Orthopedic Clinic of the Hospital Universitário do Vale do São Francisco. Methods: This is a cross-sectional, descriptive, quantitative study. Samples were collected in 13 wards, each ward with four beds and one was chosen at random, where surfaces and equipment were sampled using swabs soaked in saline and a 1cm2 filter paper mold to standardize the samples. After passing the swab, they were stored in a tube containing 5mL of BHI (Brain Heart Infusion) liquid medium. Then, samples were transported to the Clinical Analysis Laboratory/Microbiology Sector where the microbiological analyzes were performed. Results: In total, 257 bacteria were observed, of which 5.11% were possible causes of hospital infection and 79% coagulase-negative Staphylococcus. Antibiograms of these were performed and different resistance profiles were found. The bathroom doorknob, a high-touch surface, presented the greatest variety of species among the evaluated surfaces. Conclusion: Surfaces and equipment of the evaluated clinic present possible bacteria that cause hospital infection with different profiles of antimicrobial resistance, contributing to possible cross infections.(AU)