RESUMO
The interferon pathway, a key antiviral defense mechanism, is being considered as a therapeutic target in COVID-19. Both, substitution of interferon and JAK/STAT inhibition to limit cytokine storms have been proposed. However, little is known about possible abnormalities in STAT signaling in immune cells during SARS-CoV-2 infection. We investigated downstream targets of interferon signaling, including STAT1, STAT2, pSTAT1 and 2, and IRF1, 7 and 9 by flow cytometry in 30 patients with COVID-19, 17 with mild, and 13 with severe infection. We report upregulation of STAT1 and IRF9 in mild and severe COVID-19 cases, which correlated with the IFN-signature assessed by Siglec-1 (CD169) expression on peripheral monocytes. Interestingly, Siglec-1 and STAT1 in CD14+ monocytes and plasmablasts showed lower expression among severe cases compared to mild cases. Contrary to the baseline STAT1 expression, the phosphorylation of STAT1 was enhanced in severe COVID-19 cases, indicating a dysbalanced JAK/STAT signaling that fails to induce transcription of interferon stimulated response elements (ISRE). This abnormality persisted after IFN-α and IFN-γ stimulation of PBMCs from patients with severe COVID-19. Data suggest impaired STAT1 transcriptional upregulation among severely infected patients may represent a potential predictive biomarker and would allow stratification of patients for certain interferon-pathway targeted treatments.
Assuntos
COVID-19/imunologia , Monócitos/imunologia , SARS-CoV-2/imunologia , Fator de Transcrição STAT1/imunologia , Transdução de Sinais/imunologia , Regulação para Cima/imunologia , Adulto , Idoso , Feminino , Humanos , Fatores Reguladores de Interferon/imunologia , Masculino , Pessoa de Meia-Idade , Gravidade do Paciente , Fosforilação/imunologiaRESUMO
A deficient interferon (IFN) response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has been implicated as a determinant of severe coronavirus disease 2019 (COVID-19). To identify the molecular effectors that govern IFN control of SARS-CoV-2 infection, we conducted a large-scale gain-of-function analysis that evaluated the impact of human IFN-stimulated genes (ISGs) on viral replication. A limited subset of ISGs were found to control viral infection, including endosomal factors inhibiting viral entry, RNA binding proteins suppressing viral RNA synthesis, and a highly enriched cluster of endoplasmic reticulum (ER)/Golgi-resident ISGs inhibiting viral assembly/egress. These included broad-acting antiviral ISGs and eight ISGs that specifically inhibited SARS-CoV-2 and SARS-CoV-1 replication. Among the broad-acting ISGs was BST2/tetherin, which impeded viral release and is antagonized by SARS-CoV-2 Orf7a protein. Overall, these data illuminate a set of ISGs that underlie innate immune control of SARS-CoV-2/SARS-CoV-1 infection, which will facilitate the understanding of host determinants that impact disease severity and offer potential therapeutic strategies for COVID-19.
Assuntos
Antígenos CD/genética , Interações Hospedeiro-Patógeno/genética , Fatores Reguladores de Interferon/genética , Interferon Tipo I/genética , SARS-CoV-2/genética , Proteínas Virais/genética , Animais , Antígenos CD/química , Antígenos CD/imunologia , Sítios de Ligação , Linhagem Celular Tumoral , Chlorocebus aethiops , Retículo Endoplasmático/genética , Retículo Endoplasmático/imunologia , Retículo Endoplasmático/virologia , Proteínas Ligadas por GPI/química , Proteínas Ligadas por GPI/genética , Proteínas Ligadas por GPI/imunologia , Regulação da Expressão Gênica , Complexo de Golgi/genética , Complexo de Golgi/imunologia , Complexo de Golgi/virologia , Células HEK293 , Interações Hospedeiro-Patógeno/imunologia , Humanos , Imunidade Inata , Fatores Reguladores de Interferon/classificação , Fatores Reguladores de Interferon/imunologia , Interferon Tipo I/imunologia , Simulação de Acoplamento Molecular , Ligação Proteica , Conformação Proteica em alfa-Hélice , Conformação Proteica em Folha beta , Domínios e Motivos de Interação entre Proteínas , SARS-CoV-2/imunologia , Transdução de Sinais , Células Vero , Proteínas Virais/química , Proteínas Virais/imunologia , Internalização do Vírus , Liberação de Vírus/genética , Liberação de Vírus/imunologia , Replicação Viral/genética , Replicação Viral/imunologiaRESUMO
The interleukin-6 (IL-6) membrane receptor and its circulating soluble form, sIL-6R, can be targeted by antibody therapy to reduce deleterious immune signaling caused by chronic overexpression of the pro-inflammatory cytokine IL-6. This strategy may also hold promise for treating acute hyperinflammation, such as observed in coronavirus disease 2019 (COVID-19), highlighting a need to define regulators of IL-6 homeostasis. We found that conventional dendritic cells (cDCs), defined in mice via expression of the transcription factor Zbtb46, were a major source of circulating sIL-6R and, thus, systemically regulated IL-6 signaling. This was uncovered through identification of a cDC-dependent but T cell-independent modality that naturally adjuvants plasma cell differentiation and antibody responses to protein antigens. This pathway was then revealed as part of a broader biological buffer system in which cDC-derived sIL-6R set the in-solution persistence of IL-6. This control axis may further inform the development of therapeutic agents to modulate pro-inflammatory immune reactions.
Assuntos
Células Dendríticas/imunologia , Interleucina-6/sangue , Interleucina-6/imunologia , Proteína ADAM17 , Animais , Diferenciação Celular , Imunidade Humoral , Imunoglobulina M/imunologia , Inflamação , Fatores Reguladores de Interferon/genética , Fatores Reguladores de Interferon/imunologia , Interleucina-6/genética , Glicoproteínas de Membrana/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Plasmócitos/imunologia , Receptores de Interleucina-6/sangue , Receptores de Interleucina-6/imunologia , Transdução de Sinais/imunologia , Receptor 4 Toll-Like/imunologia , Receptor 7 Toll-Like/imunologiaAssuntos
Azetidinas/uso terapêutico , Betacoronavirus/patogenicidade , Infecções por Coronavirus/tratamento farmacológico , Interferon-alfa/uso terapêutico , Interferon beta/uso terapêutico , Interferons/uso terapêutico , Pneumonia Viral/tratamento farmacológico , Sulfonamidas/uso terapêutico , Betacoronavirus/imunologia , COVID-19 , Infecções por Coronavirus/imunologia , Infecções por Coronavirus/patologia , Infecções por Coronavirus/virologia , Regulação da Expressão Gênica , Humanos , Imunidade Celular/efeitos dos fármacos , Imunidade Humoral/efeitos dos fármacos , Fatores Reguladores de Interferon/genética , Fatores Reguladores de Interferon/imunologia , Interferon-alfa/genética , Interferon-alfa/imunologia , Interferon beta/genética , Interferon beta/imunologia , Interferons/genética , Interferons/imunologia , Interleucina-1/genética , Interleucina-1/imunologia , Interleucina-6/antagonistas & inibidores , Interleucina-6/genética , Interleucina-6/imunologia , Janus Quinase 1/antagonistas & inibidores , Janus Quinase 1/genética , Janus Quinase 1/imunologia , Pulmão/efeitos dos fármacos , Pulmão/imunologia , Pulmão/patologia , Pandemias , Pneumonia Viral/imunologia , Pneumonia Viral/patologia , Pneumonia Viral/virologia , Purinas , Pirazóis , SARS-CoV-2 , Índice de Gravidade de Doença , Fator de Necrose Tumoral alfa/genética , Fator de Necrose Tumoral alfa/imunologiaRESUMO
Infection caused by SARS-CoV-2 can result in severe respiratory complications and death. Patients with a compromised immune system are expected to be more susceptible to a severe disease course. In this report we suggest that patients with systemic lupus erythematous might be especially prone to severe COVID-19 independent of their immunosuppressed state from lupus treatment. Specifically, we provide evidence in lupus to suggest hypomethylation and overexpression of ACE2, which is located on the X chromosome and encodes a functional receptor for the SARS-CoV-2 spike glycoprotein. Oxidative stress induced by viral infections exacerbates the DNA methylation defect in lupus, possibly resulting in further ACE2 hypomethylation and enhanced viremia. In addition, demethylation of interferon-regulated genes, NFκB, and key cytokine genes in lupus patients might exacerbate the immune response to SARS-CoV-2 and increase the likelihood of cytokine storm. These arguments suggest that inherent epigenetic dysregulation in lupus might facilitate viral entry, viremia, and an excessive immune response to SARS-CoV-2. Further, maintaining disease remission in lupus patients is critical to prevent a vicious cycle of demethylation and increased oxidative stress, which will exacerbate susceptibility to SARS-CoV-2 infection during the current pandemic. Epigenetic control of the ACE2 gene might be a target for prevention and therapy in COVID-19.