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AimsTo assess the impact of the lockdown due to coronavirus disease 2019 (COVID-19) on key quality indicators for the treatment of ST-segment elevation myocardial infarction (STEMI) patients.MethodsData were obtained from 41 hospitals participating in the prospective Feedback Intervention and Treatment Times in ST-Elevation Myocardial Infarction (FITT-STEMI) study, including 15,800 patients treated for acute STEMI from January 2017 to the end of March 2020.ResultsThere was a 12.6% decrease in the total number of STEMI patients treated at the peak of the pandemic in March 2020 as compared to the mean number treated in the March months of the preceding years. This was accompanied by a significant difference among the modes of admission to hospitals (p = 0.017) with a particular decline in intra-hospital infarctions and transfer patients from other hospitals, while the proportion of patients transported by emergency medical service (EMS) remained stable. In EMS-transported patients, predefined quality indicators, such as percentages of pre-hospital ECGs (both 97%, 95% CI = − 2.2–2.7, p = 0.846), direct transports from the scene to the catheterization laboratory bypassing the emergency department (68% vs. 66%, 95% CI = − 4.9–7.9, p = 0.641), and contact-to-balloon-times of less than or equal to 90 min (58.3% vs. 57.8%, 95%CI = − 6.2–7.2, p = 0.879) were not significantly altered during the COVID-19 crisis, as was in-hospital mortality (9.2% vs. 8.5%, 95% CI = − 3.2–4.5, p = 0.739).ConclusionsClinically important indicators for STEMI management were unaffected at the peak of COVID-19, suggesting that the pre-existing logistic structure in the regional STEMI networks preserved high-quality standards even when challenged by a threatening pandemic.Clinical trial registrationNCT00794001

Aspergillus fumigatus is the most important airborne fungal pathogen causing life-threatening infections in immunocompromised patients. Macrophages and neutrophils are known to kill conidia, whereas hyphae are killed mainly by neutrophils. Since hyphae are too large to be engulfed, neutrophils possess an array of extracellular killing mechanisms including the formation of neutrophil extracellular traps (NETs) consisting of nuclear DNA decorated with fungicidal proteins. However, until now NET formation in response to A. fumigatus has only been demonstrated in vitro, the importance of neutrophils for their production in vivo is unclear and the molecular mechanisms of the fungus to defend against NET formation are unknown. Here, we show that human neutrophils produce NETs in vitro when encountering A. fumigatus. In time-lapse movies NET production was a highly dynamic process which, however, was only exhibited by a sub-population of cells. NETosis was maximal against hyphae, but reduced against resting and swollen conidia. In a newly developed mouse model we could then demonstrate the existence and measure the kinetics of NET formation in vivo by 2-photon microscopy of Aspergillus-infected lungs. We also observed the enormous dynamics of neutrophils within the lung and their ability to interact with and phagocytose fungal elements in situ. Furthermore, systemic neutrophil depletion in mice almost completely inhibited NET formation in lungs, thus directly linking the immigration of neutrophils with NET formation in vivo. By using fungal mutants and purified proteins we demonstrate that hydrophobin RodA, a surface protein making conidia immunologically inert, led to reduced NET formation of neutrophils encountering Aspergillus fungal elements. NET-dependent killing of Aspergillus-hyphae could be demonstrated at later time-points, but was only moderate. Thus, these data establish that NET formation occurs in vivo during host defence against A. fumigatus, but suggest that it does not play a major role in killing this fungus. Instead, NETs may have a fungistatic effect and may prevent further spreading.

Astrocytes are central to the pathogenesis of multiple sclerosis (MS); however, their regulation by post-translational ubiquitination and deubiquitination is unresolved. This study shows that the deubiquitinating enzyme OTUD7B in astrocytes protects against murine experimental autoimmune encephalomyelitis (EAE), a model of MS, by limiting neuroinflammation. RNA-sequencing of isolated astrocytes and spatial transcriptomics show that in EAE, OTUD7B downregulates chemokine expression in astrocytes of inflammatory lesions, which is associated with reduced recruitment of encephalitogenic CD4 + T cells. Furthermore, OTUD7B is necessary for glial fibrillary acidic protein (GFAP) expression of astrocytes bordering inflammatory lesions. Mechanistically, OTUD7B (i) restricts TNF-induced chemokine production of astrocytes by sequential K63- and K48-deubiquitination of RIPK1, which limits NF-κB and MAPK activation and (ii) enables GFAP protein expression by supporting GFAP mRNA expression and preventing its proteasomal degradation through K48-deubiquitination of GFAP. This dual action on TNF signaling and GFAP identifies OTUD7B as a central inhibitor of astrocyte-mediated inflammation. Astrocytes drive multiple sclerosis (MS) by enhancing inflammation. Here, the authors show that the deubiquitinase OTUD7B in astrocytes protects mice from experimental autoimmune encephalomyelitis (EAE), a model of MS, by reducing inflammation and stabilizing GFAP thereby physically restricting inflammation.

Allergic asthma has been mainly attributed to T helper type 2 (Th2) and proinflammatory responses but many cellular processes remain elusive. There is increasing evidence for distinct roles for macrophage and dendritic cell (DC) subsets in allergic airway inflammation (AAI). At the same time, there are various mouse models for allergic asthma that have been of utmost importance in identifying key inflammatory pathways in AAI but that differ in the allergen and/or route of sensitization. It is unclear whether and how the accumulation and activation of specialized macrophage and DC subsets depend on the experimental model chosen for analyses. In our study, we employed high-parameter spectral flow cytometry to comprehensively assess the accumulation and phenotypic alterations of different macrophage- and DC-subsets in the lung in an OVA- and an HDM-mediated mouse model of AAI. We observed subset-specific as well as model-specific characteristics with respect to cell numbers and functional marker expression. Generally, alveolar as opposed to interstitial macrophages showed increased MHCII surface expression in AAI. Between the models, we observed significantly increased numbers of alveolar macrophages, CD103 DC and CD11b DC in HDM-mediated AAI, concurrent with significantly increased airway interleukin-4 but decreased total serum IgE levels. Further, increased expression of CD80 and CD86 on DC was exclusively detected in HDM-mediated AAI. Our study demonstrates a model-specific involvement of macrophage and DC subsets in AAI. It further highlights spectral flow cytometry as a valuable tool for their comprehensive analysis under inflammatory conditions in the lung.

Background: Patients with ulcerative colitis (UC) suffer from a chronic relapsing-remitting inflammatory bowel disease and show heterogeneous disease severity and therapy response. It was recently reported that rectal biopsies from patients with UC show a downregulation of various mitochondrial genes during active UC. Methods: We used dextran sulfate sodium (DSS)-induced colitis as a preclinical mouse model for UC to study metabolic characteristics of ex vivo colonic lamina propria CD4+ and CD8+ T cells, B cells, eosinophils, neutrophils and intestinal epithelial cells during experimental acute and chronic inflammatory bowel disease and remission state. Results: Our results indicate that CD4+ and CD8+ T cells in the colon produce significantly less mitochondrial reactive oxygen species and possess smaller mitochondria during chronic DSS-induced colitis, which is resolved during remission state. In addition, CD4+ and CD8+ T cells exhibit increased glucose uptake during acute but defective glucose consumption during chronic DSS colitis. Conclusions: Together, our data provide evidence for an atypical mitochondrial phenotype of colonic CD4+ and CD8+ T cells during chronic colitis that is resolved during the remission phase of the disease.

IκB proteins regulate the inhibition and activation of NF-κB transcription factor complexes. While classical IκB proteins keep NF-κB complexes inactive in the cytoplasm, atypical IκB proteins act on activated NF-κB complexes located in the nucleus. Most of the knowledge regarding the function of IκB proteins has been collected in vitro , while far less is known regarding their impact on activation and regulation of immune responses during in vivo infections. Combining in vivo Listeria monocytogenes (Lm) infection with comparative ex vivo transcriptional profiling of the hepatic response to the pathogen we observed that in contrast to wild type mice that mounted a robust inflammatory response, IκB NS -deficiency was generally associated with a transcriptional repression of innate immune responses. Whole tissue transcriptomics revealed a pronounced IκB NS -dependent reduction of myeloid cell-associated transcripts in the liver together with an exceptionally high Nfkbid promoter activity uncovered in Ly6C high inflammatory monocytes prompted us to further characterize the specific contribution of IκB NS in the inflammatory response of monocytes to the infectious agent. Indeed, Ly6C high monocytes primed during Lm infection in the absence of IκB NS displayed a blunted response compared to wild type-derived Ly6C high monocytes as evidenced by the reduced early expression of hallmark transcripts of monocyte-driven inflammation such as Il6 , Nos2 and Il1β . Strikingly, altered monocyte activation in IκB NS -deficient mice was associated with an exceptional resistance against Lm infection and protection was associated with a strong reduction in immunopathology in Lm target organs. Of note, mice lacking IκB NS exclusively in myeloid cells failed to resist Lm infection, indicating that the observed effect was not monocyte intrinsic but monocyte extrinsic. While serum cytokine-profiling did not discover obvious differences between wild type and IκB NS -/- mice for most of the analyzed mediators, IL-10 was virtually undetectable in IκB NS -deficient mice, both in the steady state and following Lm infection. Together, we show here a crucial role for IκB NS during Lm infection with IκB NS -deficient mice showing an overall blunted pro-inflammatory immune response attributed to a reduced pro-inflammatory signature in Ly6C high monocytes. Reduced immunopathology and complete protection of mice against an otherwise fatal Lm infection identified IκB NS as molecular driver of inflammation in listeriosis.

Background Pneumococcal pneumonia following influenza A virus (IAV) infection is a synergistic complication with high mortality in which IAV infection modulates host antibacterial responses and affects bacterial invasiveness of Streptococcus pneumoniae ( S. pn. ). IAV-mediated effects can last beyond viral clearance. In acute IAV pneumonia, alveolar type II epithelial cells (AECII) are primary targets for viral replication and contribute to the immune response. Our study addresses sustained effects of IAV infection on AECII and consequences for their response towards different serotypes of S. pn. Methods We analyzed bacterial loads, respiratory inflammation and AECII gene transcription profiling in mice infected with IAV and/or one of three S. pn. serotypes of varying invasiveness (4 > 7F > 19F). We inferred a scale-free-like ARACNE gene co-expression network on AECII transcriptional regulation under these conditions. We performed Western blotting for protein expression of interferon signaling components in AECII. We additionally performed ATAC-seq analysis of AECII isolated 14 days following IAV infection. Results Previous IAV infection rendered the lung susceptible to invasive S. pn. infection with serotype 4 and the mildly invasive 7F but not 19F. Particularly secondary infection with 7F induced exacerbated inflammatory responses as compared to bacterial infection alone, marked by increased protein expression of type I and II interferons. AECII gene co-expression network revealed interferon-response network modules. Network-mapping unfolded S. pn. serotype-specific transcriptional network responses/usage and secondary S. pn. infection was found to abrogate an IAV-induced AECII proliferative configuration. Enhanced expression of several ARACNE network genes were found to be associated with increased chromatin accessibility at their promoter regions. Conclusions Our study demonstrates AECII to retain a sustained IAV-associated configuration with epigenetic involvement, affecting their proliferation and serotype-specifically intensifying their transcriptional response, mainly to interferons, in secondary S. pn. infection. In a broader context, our results suggest the concepts of peripheral inflammatory imprinting and trained innate immunity to apply to cells of the respiratory epithelium in the context of subsequent viral/bacterial challenges. Plain english summary After an influenza A virus (IAV) infection, the lungs become more vulnerable to bacterial infections caused by Streptococcus pneumoniae ( S. pn. ). This effect can last even after the virus is cleared. Alveolar type II epithelial cells (AECII) in the lungs are primary targets for IAV and play a crucial role in the immune response. Our study examines how IAV infection affects AECII and their response to different S. pn. serotypes. We studied mice infected with IAV and three S. pn. serotypes to analyze bacterial loads, inflammation, and gene activity in AECII. We discovered that previous IAV infection made lungs more susceptible to certain S. pn. serotypes. Specifically, secondary infection with serotype 7F caused a stronger inflammatory response, marked by increased type I and II interferons. Our research revealed that AECII maintain changes caused by IAV, affecting their growth and response to bacteria. These changes are linked to alterations in gene accessibility within AECII. In summary, IAV leaves lasting effects on lung cells, making them more responsive to specific bacterial infections through enhanced interferon responses. This supports the idea that lung cells “remember” past infections, which affects their response to new ones, reflecting the concept of “trained immunity”.

Influenza A virus (IAV) periodically causes substantial morbidity and mortality in the human population. In the lower lung, the primary targets for IAV replication are type II alveolar epithelial cells (AECII), which are increasingly recognized for their immunological potential. So far, little is known about their reaction to IAV and their contribution to respiratory antiviral immunity in vivo . Therefore, we characterized the AECII response during early IAV infection by analyzing transcriptional regulation in cells sorted from the lungs of infected mice. We detected rapid and extensive regulation of gene expression in AECII following in vivo IAV infection. The comparison to transcriptional regulation in lung tissue revealed a strong contribution of AECII to the respiratory response. IAV infection triggered the expression of a plethora of antiviral factors and immune mediators in AECII with a high prevalence for interferon-stimulated genes. Functional pathway analyses revealed high activity in pathogen recognition, immune cell recruitment, and antigen presentation. Ultimately, our analyses of transcriptional regulation in AECII and lung tissue as well as interferon I/III levels and cell recruitment indicated AECII to integrate signals provided by direct pathogen recognition and surrounding cells. Ex vivo analysis of AECII proved a powerful tool to increase our understanding of their role in respiratory immune responses, and our results clearly show that AECII need to be considered a part of the surveillance and effector system of the lower respiratory tract. IMPORTANCE In order to confront the health hazard posed by IAV, we need to complete our understanding of its pathogenesis. AECII are primary targets for IAV replication in the lung, and while we are beginning to understand their importance for respiratory immunity, the in vivo AECII response during IAV infection has not been analyzed. In contrast to studies addressing the response of AECII infected with IAV ex vivo , we have performed detailed gene transcriptional profiling of AECII isolated from the lungs of infected mice. Thereby, we have identified an exceptionally rapid and versatile response to IAV infection that is shaped by pathogen-derived as well as microenvironment-derived signals and aims at the induction of antiviral measures and the recruitment and activation of immune cells. In conclusion, our study presents AECII as active players in antiviral defense in vivo that need to be considered part of the sentinel and effector immune system of the lung. In order to confront the health hazard posed by IAV, we need to complete our understanding of its pathogenesis. AECII are primary targets for IAV replication in the lung, and while we are beginning to understand their importance for respiratory immunity, the in vivo AECII response during IAV infection has not been analyzed. In contrast to studies addressing the response of AECII infected with IAV ex vivo , we have performed detailed gene transcriptional profiling of AECII isolated from the lungs of infected mice. Thereby, we have identified an exceptionally rapid and versatile response to IAV infection that is shaped by pathogen-derived as well as microenvironment-derived signals and aims at the induction of antiviral measures and the recruitment and activation of immune cells. In conclusion, our study presents AECII as active players in antiviral defense in vivo that need to be considered part of the sentinel and effector immune system of the lung.

Upon antigen recognition by the T cell receptor (TCR), a complex signaling network orchestrated by protein-tyrosine kinases (PTKs) and protein-tyrosine phosphatases (PTPs) regulates the transmission of the extracellular signal to the nucleus. The role of the PTPs Src-homology 2 (SH2) domain-containing phosphatase 1 (SHP1, Ptpn6 ) and Src-homology 2 (SH2) domain-containing phosphatase 2 (SHP2, Ptpn11 ) have been studied in various cell types including T cells. Whereas SHP1 acts as an essential negative regulator of the proximal steps in T cell signalling, the role of SHP2 in T cell activation is still a matter of debate. Here, we analyzed the role of the constitutively active SHP2-D61Y-mutant in T cell activation using knock-in mice expressing the mutant form Ptpn11 D61Y in T cells. We observed reduced numbers of CD8 + and increased numbers of CD4 + T cells in the bone marrow and spleen of young and aged SHP2-D61Y-mutant mice as well as in Influenza A Virus (IAV)-infected mice compared to controls. In addition, we found elevated frequencies of effector memory CD8 + T cells and an upregulation of the programmed cell death protein 1 (PD-1)-receptor on both CD4 + and CD8 + T cells. Functional analysis of SHP2-D61Y-mutated T cells revealed an induction of late apoptosis/necrosis, a reduced proliferation and altered signaling upon TCR stimulation. However, the ability of D61Y-mutant mice to clear viral infection was not affected. In conclusion, our data indicate an important regulatory role of SHP2 in T cell function, where the effect is determined by the kinetics of SHP2 phosphatase activity and differs in the presence of the permanently active and the temporally regulated phosphatase. Due to interaction of SHP2 with the PD-1-receptor targeting the protein-tyrosine phosphatase might be a valuable tool to enhance T cell activities in immunotherapy.