Anna-Dorothea Gorki

Pulmonary fibrosis is an incurable disease that manifests with advanced age. Yet, how hematopoietic aging influences immune responses and fibrosis progression remains unclear. Using heterochronic bone marrow transplant mouse models, we found that an aged bone marrow exacerbates lung fibrosis irrespective of lung tissue age. Upon lung injury, there was an increased accumulation of monocyte-derived alveolar macrophages (Mo-AMs) driven by cell-intrinsic hematopoietic aging. These Mo-AMs exhibited an enhanced profibrotic profile and stalled maturation into a homeostatic, tissue-resident phenotype. This delay was shaped by cell-extrinsic environmental signals such as reduced pulmonary interleukin-10 (IL-10), perpetuating a profibrotic macrophage state. We identified regulatory T cells (T _regs ) as critical providers of IL-10 upon lung injury that promote Mo-AM maturation and attenuate fibrosis progression. Our study highlights the impact of an aging bone marrow on lung immune regulation and identifies T _reg -mediated IL-10 signaling as a promising target to mitigate fibrosis and promote tissue repair.

Community-acquired pneumonia (CAP), often caused by Streptococcus pneumoniae , poses a significant global health challenge, especially among high-risk populations. This study investigates the temporal dynamics of pulmonary gene expression during S. pneumoniae -induced pneumonia using a murine model to elucidate host-pathogen interactions and identify potential biomarkers of disease severity. Using bulk RNA sequencing, we analyzed lung tissues at early (1h, 8h) and acute infection (2d, 3d), as well as post-resolution (30d) time-points. At 2 days post-infection, differentially expressed genes (DEGs) revealed heightened innate immune responses, including chemokine and interferon signaling pathways. By 30 days post-infection, gene expression profiles and histological changes normalized, reflecting resolution of inflammation. Stratifying mice into recovered, sick, and moribund phenotypes during the acute infection phase highlighted significant transcriptional distinctions, including upregulated pro-inflammatory genes and Schlafen family members. Arginase 1 emerged as a predictive marker of disease severity, with elevated expression detectable as early as 8 hours post-infection. Comparative analyses revealed significant overlap between transcriptional responses in our model and those from a Gram-negative Acinetobacter baumannii pneumonia model, implicating conserved pathways, such as IL-17 and Toll-like receptor signaling. Additionally, murine DEGs correlated with human plasma proteins associated with severe CAP, including CCL8 and CD14, suggesting translational relevance. This study underscores phase-specific transcriptional reprogramming during pneumococcal pneumonia and identifies potential biomarkers and therapeutic targets for improving outcomes in severe CAP cases.

Respiratory viral infections caused by rhinoviruses (RVs), influenza A virus (IAV) and endemic corona viruses (HCoV) result in a serious strain on healthcare systems and public health, underscoring an urgent need for inhaled broad-spectrum antiviral therapies. However, their development is challenging, as no standardized in vitro methodologies that can fully replicate the in vivo environment have been established. In this work, we aimed to investigate the antiviral and anti-inflammatory effect of three 2-deoxylated glucose analogues (2-DGA): 2-deoxy-D-glucose, 2-fluoro-2-dexoy-D-glucose and 2-fluoro-2-dexoy-D-mannose (2-FDM), by utilizing advanced in vitro air-liquid interface (ALI) airway models. We demonstrated that commonly used ALI models have variable susceptibility to RV, IAV and HCoV infection. Further, we showed that 2-DGA have an anti-inflammatory effect and suppress respiratory viral replication in models mimicking the upper and lower respiratory airways. Moreover, we confirmed that 2-DGA can be delivered via nebulization in vitro , highlighting their potential to be used as broad-spectrum inhaled antivirals. Finally, our results demonstrate the importance of incorporating complex in vitro methodologies, such as primary cell ALI cultures and aerosol exposure, at an early stage of drug development.

Immune cells need to sustain a state of constant alertness over a lifetime. Yet, little is known about the regulatory processes that control the fluent and fragile balance that is called homeostasis. Here we demonstrate that JAK-STAT signaling, beyond its role in immune responses, is a major regulator of immune cell homeostasis. We investigated JAK-STAT-mediated transcription and chromatin accessibility across 12 mouse models, including knockouts of all STAT transcription factors and of the TYK2 kinase. Baseline JAK-STAT signaling was detected in CD8⁺ T cells and macrophages of unperturbed mice—but abrogated in the knockouts and in unstimulated immune cells deprived of their normal tissue context. We observed diverse gene-regulatory programs, including effects of STAT2 and IRF9 that were independent of STAT1. In summary, our large-scale dataset and integrative analysis of JAK-STAT mutant and wild-type mice uncovered a crucial role of JAK-STAT signaling in unstimulated immune cells, where it contributes to a poised epigenetic and transcriptional state and helps prepare these cells for rapid response to immune stimuli.

Sepsis is a life-threatening condition characterized by uncontrolled systemic inflammation and coagulation, leading to multiorgan failure. Therapeutic options to prevent sepsis-associated immunopathology remain scarce. Here, we established a mouse model of long-lasting disease tolerance during severe sepsis, manifested by diminished immunothrombosis and organ damage in spite of a high pathogen burden. We found that both neutrophils and B cells emerged as key regulators of tissue integrity. Enduring changes in the transcriptional profile of neutrophils include upregulated Cxcr4 expression in protected, tolerant hosts. Neutrophil Cxcr4 upregulation required the presence of B cells, suggesting that B cells promoted disease tolerance by improving tissue damage control via the suppression of neutrophils’ tissue-damaging properties. Finally, therapeutic administration of a Cxcr4 agonist successfully promoted tissue damage control and prevented liver damage during sepsis. Our findings highlight the importance of a critical B-cell/neutrophil interaction during sepsis and establish neutrophil Cxcr4 activation as a potential means to promote disease tolerance during sepsis.

Rhinoviruses (RVs) and coronaviruses (CoVs) upregulate host cell metabolic pathways such as glycolysis to meet their bioenergetic demands for rapid multiplication. Using the glycolysis inhibitor 2-deoxy-D-glucose (2-DG), we assessed the dose-dependent inhibition of viral replication of minor- and major-receptor group RVs in epithelial cells. 2-DG disrupted RV infection cycle by inhibiting template negative-strand as well as genomic positive-strand RNA synthesis, resulting in less progeny virus and RV-mediated cell death. Assessment of 2-DG’s intracellular kinetics revealed that after a short-exposure to 2-DG, the active intermediate, 2-DG6P, is stored intracellularly for several hours. Finally, we confirmed the antiviral effect of 2-DG on pandemic SARS-CoV-2 and showed for the first time that 2-DG also reduces replication of endemic human coronaviruses (HCoVs). These results provide further evidence that 2-DG could be utilized as a broad-spectrum antiviral. HIGHLIGHTS: 2-DG inhibits replication of minor- and major-group rhinoviruses in epithelial cells including human nasal epithelial cell. 2-DG disrupts rhinovirus infection cycle and reduces rhinovirus-mediated cell death in vitro . 2-DG treatment attenuates viral load of endemic coronaviruses in vitro .

Sepsis is a life-threatening condition characterized by uncontrolled systemic inflammation and coagulation, leading to multi-organ failure. Therapeutic options to prevent sepsis-associated immunopathology remain scarce. Here, we established a model of long-lasting disease tolerance during severe sepsis, manifested by diminished immunothrombosis and organ damage in spite of a high pathogen burden. We found that, both neutrophils and B cells emerged as key regulators of tissue integrity. Enduring changes in the transcriptional profile of neutrophils, included upregulated Cxcr4 expression in protected, tolerant hosts. Neutrophil Cxcr4 upregulation required the presence of B cells, suggesting that B cells promoted tissue tolerance by suppressing tissue damaging properties of neutrophils. Finally, therapeutic administration of a Cxcr4 agonist successfully promoted tissue tolerance and prevented liver damage during sepsis. Our findings highlight the importance of a critical B-cell/neutrophil interaction during sepsis and establish neutrophil Cxcr4 activation as a potential means to promote disease tolerance during sepsis. Summary We show that a B cell/neutrophil interaction in the bone marrow facilitates tissue tolerance during severe sepsis. By affecting neutrophil Cxcr4 expression, B cells can impact neutrophil effector functions. Finally, therapeutic activation of Cxcr4 successfully promoted tissue tolerance and prevented liver damage during sepsis.

Tissue-resident macrophages are of vital importance as they preserve tissue homeostasis in all mammalian organs. Nevertheless, appropriate cell culture models are still limited. Here, we propose a novel culture model to study and expand murine primary alveolar macrophages (AMs), the tissue-resident macrophages of the lung, in vitro over several months. By providing a combination of granulocyte-macrophage colony-stimulating factor, TGFβ, and the PPARγ activator rosiglitazone, we maintain and expand mouse ex vivo cultured AMs (mexAMs) over several months. MexAMs maintain typical morphologic features and stably express primary AM surface markers throughout in vitro culture. They respond to microbial ligands and exhibit an AM-like transcriptional profile, including the expression of AM-specific transcription factors. Furthermore, when transferred into AM-deficient mice, mexAMs efficiently engraft in the lung and fulfill key macrophage functions, leading to a significantly reduced surfactant load in those mice. Altogether, mexAMs provide a novel, simple, and versatile tool to study AM behavior in homeostasis and disease settings.