Project description:Inborn errors of human IFN-γ immunity underlie mycobacterial diseases, while inborn errors of IFN-a/b immunity underlie viral diseases. Both types of IFNs induce the transcription factor IRF1. We describe two unrelated children with inherited complete IRF1 deficiency and early-onset, multiple, life-threatening diseases caused by weakly virulent mycobacteria. They have no history of severe viral disease, despite exposure to many viruses, including SARS-CoV-2 that is life-threatening in individuals with deficient IFN-a/b. There is a much greater IRF1-dependent response to IFN-γ than IFN-a/b in vitro, both quantitatively and qualitatively. Monocyte-derived macrophages and iPSC-derived macrophages of both patients do not upregulate at least 40% of target genes normally induced by IFN-γ. In contrast, cell-intrinsic IFN-a/b immunity to a wide range of viruses, including HIV and SARS-CoV-2, is maintained. Human IRF1 is thus largely redundant for antiviral IFN-a/b immunity across cell types. By contrast, human IRF1 is essential for IFN-γ immunity to mycobacteria in mononuclear myeloid cells.
Project description:Inborn errors of human IFN-γ immunity underlie mycobacterial diseases, while inborn errors of IFN-a/b immunity underlie viral diseases. Both types of IFNs induce the transcription factor IRF1. We describe two unrelated children with inherited complete IRF1 deficiency and early-onset, multiple, life-threatening diseases caused by weakly virulent mycobacteria. They have no history of severe viral disease, despite exposure to many viruses, including SARS-CoV-2 that is life-threatening in individuals with deficient IFN-a/b. There is a much greater IRF1-dependent response to IFN-γ than IFN-a/b in vitro, both quantitatively and qualitatively. Monocyte-derived macrophages and iPSC-derived macrophages of both patients do not upregulate at least 40% of target genes normally induced by IFN-γ. In contrast, cell-intrinsic IFN-a/b immunity to a wide range of viruses, including HIV and SARS-CoV-2, is maintained. Human IRF1 is thus largely redundant for antiviral IFN-a/b immunity across cell types. By contrast, human IRF1 is essential for IFN-γ immunity to mycobacteria in mononuclear myeloid cells.
Project description:Anti-viral innate immunity represents the first line of defense against invading viruses and is key to control viral infections, including the pandemic SARS-CoV-2. Body temperature is an omnipresent variable but was so far neglected when addressing host defense mechanisms and susceptibility to SARS-CoV-2 infection. Here we show that increasing temperature in a 1.5°C window, between 36.5°C and 38°C, strongly increases anti-viral immunity. We show that alternative splicing coupled to nonsense-mediated decay decreases STAT2 expression in colder conditions and suggest that increased STAT2 expression at elevated temperature induces the expression of diverse anti-viral genes. This cascade is activated in a remarkably narrow temperature range below febrile temperature, which reflects individual, circadian and age-dependent body temperature variation. Accordingly, decreased body temperature with ageing correlates with reduced expression of anti-viral genes in older individuals. Using cell culture and in vivo models, we show that higher body temperature indeed reduces SARS-CoV-2 replication, which likely impacts on the different vulnerability of children versus seniors towards severe SARS-CoV-2 infection. Altogether, our data reveal a molecular mechanism, from temperature sensing and pre-mRNA processing to an in vivo phenotype connecting body temperature variation with SARS-CoV-2 replication, thus providing a new paradigm for the regulation of anti-viral innate immunity.
Project description:Influenza is the common respiratory problem that infects between 5-20% of the US population and results in 30,000 deaths annually. A primary cause of the influenza-associated death is due to secondary bacterial pneumonia. In this study, we investigated the role of STAT2 signaling during influenza and influenza-bacterial super-infection in mice. Herein, we demonstrate that STAT2 signaling is required for viral control, regulation of inflammation, and limiting mortality during influenza single infection. Surprisingly, despite this deficiency in anti-viral immunity, we found increased bacterial control and survival in STAT2 deficient mice during influenza-MRSA super-infection compared to controls. This protection in the absence of STAT2 was associated with accumulation of dual phenotype M1/M2 macrophages, which were required for control of bacterial infection. Together, these results suggest that the STAT2 signaling is involved in suppressing macrophage activation and bacterial control during influenza-bacterial super-infection.
2018-12-26 | GSE119029 | GEO
Project description:Inherited human TNF deficiency undermines macrophages respiratory burst and underlies recurrent pulmonary tuberculosis
Project description:To further understand the role of phosphorylation in ISGF3- and STAT2/IRF9-mediated constitutive and long-term IFN-I-stimulated transcriptional responses, we performed RNA-Seq and ChIP-Seq, in combination with phosphorylation inhibition and anti-viral experiments. First, we identified a group of ISRE-containing ISGs that were commonly regulated in IFNα treated WT and STAT1-KO cells. Thus, in 2fTGH and Huh7.5 WT cells IFNα-inducible transcription and anti-viral activity relied on the recruitment of the ISGF3 components STAT1, STAT2 and IRF9 in a phosphorylation- and time-dependent manner. Likewise, in ST2-U3C and Huh-STAT1KO cells lacking STAT1, ISG expression correlated with DNA-binding of phosphorylated STAT2/IRF9. This pointed to a dominant role of classical ISGF3 and STAT2/IRF9, and not U-ISGF3 or U-STAT2/IRF9, in the regulation of early and prolonged ISG expression and viral protection, in WT and STAT1-KO cells. In addition, comparative experiments in U3C (STAT1-KO) cells overexpressing all ISGF3 components (ST1-ST2-IRF9-U3C), revealed a threshold-dependent role of U-ISFG3, and potentially U-STAT2/IRF9, in the regulation of constitutive and possibly long-term IFNα-treated ISG expression and anti-viral activity.
Project description:Inborn errors of human IFN-γ immunity underlie mycobacterial diseases, whereas inborn errors of IFN-a/b immunity underlie viral diseases. Both types of IFNs induce the transcription factor IRF1. We describe two unrelated children with inherited complete IRF1 deficiency and early-onset, multiple, life-threatening diseases caused by weakly virulent mycobacteria. These children have no history of severe viral disease, despite exposure to many viruses, including SARS-CoV-2, which is life-threatening in individuals with impaired IFN-a/b immunity. The IRF1-dependent cellular responses to IFN-γ are, both quantitatively and qualitatively, much greater than those to IFN-a/b in vitro. Monocyte- and iPSC-derived macrophages from the two patients show no upregulation of at least 20% of the target genes normally induced by IFN-γ. By contrast, cell-intrinsic IFN-a/b immunity to diverse viruses, including SARS-CoV-2, is intact. Human IRF1 is, thus, largely redundant for antiviral IFN-a/b immunity. By contrast, human IRF1 is essential for IFN-γ immunity to mycobacteria in myeloid cells.