Biology subjects

Schmolke, M.

Publications and source records attributed to Schmolke, M..

5 recordsLinked to original sources

bioRxiv2026

Early metabolic reprogramming licenses Streptococcus pneumoniae for Influenza-driven superinfection

Bacterial pneumonia remains a major cause of morbidity and mortality following influenza A virus (IAV) infection. However, the adaptive mechanisms that enable pathogen expansion in the post-viral lung remain poorly defined. Here, using a mouse model of IAV-Streptococcus pneumoniae superinfection, we characterize bacterial transcriptional reprogramming in vivo. We identify alcohol dehydrogenases (AdhA and AdhE), that support NAD regeneration during mixed-acid fermentation, as key determinants of bacterial fitness specifically in the IAV-primed lung. Genetic deletion of these results in a pronounced fitness defect during superinfection but not in primary bacterial pneumonia. Consistent with this requirement, pharmacological inhibition of alcohol dehydrogenases limits bacterial expansion and dissemination following IAV infection. Mechanistically, we show that IAV infection profoundly remodels the lung environment, inducing hypoxia and increasing the availability of alternative carbon sources, which together impose a metabolic dependency on Adh for bacterial expansion. Our findings place metabolic adaptation as a central driver of pneumococcal outgrowth following viral infection and reveal exploitable vulnerabilities for therapeutic intervention.

microbiology↗

bioRxiv2025

Cross-species comparative modelling of antimicrobial host responses ex vivo in human and murine precision cut lung slices and in vivo in mice

Tissue resident host responses to microbial infections in the respiratory tract are highly dynamic in space and time and rely on the interaction of a multitude of cell types. In an attempt to model these multicellular responses reliably in cell culture, we compare here the global transcriptional antimicrobial response to infection with influenza A virus (IAV) in precision cult lung slices (PCLS), volume defined organ discs largely maintaining the cellular composition and 3D architecture of the donor lung. To permit a fair comparison of host responses in an isogenic background we first challenged mice in vivo and murine PCLS (mPCLS) and assess host transciptomic changes by unbiased RNAseq. While core antiviral responses overlapped substantially, mPCLS lacked certain features--such as type II interferon expression--likely due to the absence of infiltrating immune cells responses. Importantly, when expanding our findings to immune experienced human precision cut lung slices (hPCLS), we find a much broader antiviral response after IAV challenge, including type I, II and III interferons, suggesting the presence of responsive tissue resident lymphocytes. To prove specificity of this response we infected hPCLS with Streptococcus pneumoniae. Ex vivo tissues responded with a distinct proinflammatory gene profile including IL1A, IL1B and IL17 expression. Blocking of IL-1 signaling partially inhibited the proinflammatory response, suggesting cellular cross-talk and a complex and specific antimicrobial reaction in this ex vivo model. In conclusion diversified tissue resident immune cell compartment distinguishes the human ex vivo model, making it an ideal system for microbiological and immunological research. ImportancePathogen interactions with the lung are very dynamic processes. In biomedical research it is paramount to model these processes in the laboratory as accurately as possible. Influenza A virus has been extensively studied in epithelial cell culture models, including advanced organoids and organ on a chip systems. We use here ex vivo cultured PCLS and use transcriptomics to assess the global tissue resident host response to viral and bacterial challenge. Our data show 1) that murine PCLS faithfully reflect core responses to viral infection, while missing proinflammatory responses linked to infiltrating immune cells and 2) that human PCLS show a highly diversified tissue resident immune response to viral infection due to previous exposures of the host to this pathogen. These responses are clearly distinct from antibacterial gene profiles. Our data advertise PCLS as a complex and realistic model to study tissue resident immune responses to microbes in a human system.

immunology↗

bioRxiv2021

Optimizing the live attenuated influenza A vaccine backbone for high-risk patient groups

The live attenuated influenza vaccine (LAIV) is approved for intranasal spray application in 2-49 year-old patients with safety concerns limiting its use in younger children and immunocompromised patients, mainly from the higher incidence of adverse events and the possibility of uncontrolled replication and reversion to a pathogenic strain, respectively. Further attenuation of the LAIV could generally improve its safety profile, which might come at the cost of reduced immunogenicity. To solve this dilemma, we took advantage of a recently defined mechanism of ER stress induction by modifying IAV non-structural protein 1 (NS1). The modified LAIV (AAmut/PR8) showed stronger ER stress activation in vitro and replicated to lower titers in vivo compared to its parental strain, without affecting protection against homo-subtypic or hetero-subtypic IAV strains. AAmut/PR8 could pose as a suitable strategy to attend the gap to the current LAIV recommendation guidelines in susceptible target populations.

microbiology↗

bioRxiv2019

Genetic analysis of Aegilops tauschii-derived seedling resistance to leaf rust in synthetic hexaploid wheat

Seedling resistance to leaf rust available in the synthetic hexaploid wheat line Syn137 was characterized by means of cytogenetic and linkage mapping. Monosomic analysis located a single dominant gene for leaf rust resistance on chromosome 5D. Molecular mapping not only confirmed this location but also positioned the gene to the distal part of the long arm of chromosome 5D. A test of allelism showed that the gene, tentatively named LrSyn137, is independent but closely linked to Lr1. It appears that Syn137 is occasionally heterogeneous for Lr1 since the analysis of the Lr1-specific marker RGA567-5 in the mapping population indicated the presence of Lr1. Syn137 represents another source of genetic variation that can be useful for the diversification of leaf rust resistance in wheat cultivars.

genetics↗

bioRxiv2018

Microbiome disturbance and resilience dynamics of the upper respiratory tract in response to influenza A virus infection in analog hosts

Infection with influenza can be aggravated by bacterial co-infections, which often results in disease exacerbation because of host responses and cellular damage. The native upper respiratory tract (URT) microbiome likely plays a role, yet the effects of influenza infection on the URT microbiome are largely unknown. We performed a longitudinal study to assess the temporal dynamics of the URT microbiomes of uninfected and influenza virus-infected humans and ferrets. Uninfected human patients and ferret URT microbiomes had stable \"heathy ecostate\" communities both within and between individuals. In contrast, infected patients and ferrets exhibited large changes in bacterial community composition over time and between individuals. The \"unhealthy\" ecostates of infected individuals progressed towards the \"healthy ecostate\" over time, coinciding with viral clearance and recovery. Blooms of Pseudomonas were a statistically associated constant in the disturbed microbiomes of infected individuals. The dynamic and resilient nature of the microbiome during influenza virus infection in multiple hosts provides a compelling rationale for the maintenance of the microbiome homeostasis as a potential therapeutic target to prevent IAV associated bacterial co-infections.\n\nOne Sentence SummaryDynamics of the upper respiratory tract microbiome during influenza A virus infection

microbiology↗