Universität zu Lübeck

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Auflistung Universität zu Lübeck nach Instituten/Kliniken "Forschungszentrum Borstel, Leibniz Lungenzentrum"

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    Comparative analysis of host response in tuberculosis across species
    (2024-10-24) Tijani, Hawanot Olaitan
    In tuberculosis (TB) studies, the extent to which host genome as well as transcriptome contribute to susceptibility and pathology has not been clearly defined. Globally still one of the most abundant infectious disease, numbers of TB cases caused by drug resistant agents of the Mycobacterium tuberculosis (M. tuberculosis) complex are increasing especially with onset of emerging and re-emerging viral diseases and other comorbidities. Our study aims to identify host specific differences in TB disease susceptibility and pathogenesis. Previously, we and others have demonstrated the detrimental role of neutrophils in necrosis, tissue damage and bacterial spread. We hypothesized that cell death modalities during the interaction of neutrophils and other myeloid cells in the lung determines pathogen restriction or spread and ultimately, disease exacerbation. We therefore designed an integrative systems biology approach from genome to cellular, tissue and animal model to better understand TB in vitro and in vivo. Inbred female congenic mice differing in their susceptibility to M. tuberculosis infection were studied before, during and after infection and compared to human leukocytes and RNA samples from excised lung tissue. Murine bone marrow derived macrophages from wild-type B6 in comparison to susceptible C3HeBFeJ and B6.C3Hsst1 mice showed differential responses to M. tuberculosis. Upon aerosol infection with M. tuberculosis, immune-competent but susceptible B6.I-9.3.19.8 and B6.C3Hsst1 had bigger lung lesions and higher bacterial loads than resistant B6 mice. Immune cell phenotyping of murine lung samples characterized by flow cytometry and immunohistochemistry revealed distinct composition of immune cells between susceptible and resistant mouse strains. Importantly, human PMN and PBMCs showed infection specific transcriptional profiles in vitro skewed towards active phagocytosis. Comparative analyses of both murine and human transcriptome identified unique genes for each data set and shared genes across the samples. Taken together, our findings will contribute to better understand TB disease processes in order to break disease transmission, reducing bacterial burden in active TB patients, shortening treatment duration, and eventually preventing disease development in latent TB cases.
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    Influence of alterations in iron metabolism on anti-mycobacterial host defense
    (2023) Akoh-Arrey, Jessica Ebot-Otang
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    Macrophage-specific Arginase-1
    (2024) Baumann, Anna
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    Multidrug resistance, population structure, and epidemiology of Mycobacterium tuberculosis complex strains from West Africa
    (2025-02-25) Blankson, Harriet Naa Afia
    Tuberculosis (TB) remains a global public health challenge, impacting millions of individuals and placing a substantial burden on healthcare systems worldwide. The causative agents of TB, Mycobacterium tuberculosis complex (MTBC) strains, engage in a complex interplay of factors that influence its transmission, evolution, and the emergence of drug-resistant strains. Despite commendable progress in TB control efforts, the persistent threat of multidrug-resistant TB(MDR-TB), characterized by resistance to both isoniazid (INH) and rifampicin (RIF), has significantly complicated treatment protocols. Recent recommendations by the World Health Organization (WHO) advocate for a new all-oral 6-month regimen to address MDR-TB. However, concerns arise with the development of resistance to fluoroquinolones (FQs) and bedaquiline (BDQ), potentially jeopardizing the regimen's efficacy. Documented outbreaks of MTBC strains, particularly of MDR strains, underscore the urgency of monitoring the transmission of MTBC strains, as it can impact diagnostics and treatment strategies in affected regions. Specific strains within MTBC lineages may exhibit unique traits, such as varying minimum inhibitory concentrations (MIC) or inherent resistance to specific drugs. Understanding the circulating MTBC strains in a country, their drug resistance profiles, and their evolutionary dynamics is imperative for effective TB management. To close these knowledge gaps, this thesis seeks to explore the multifaceted landscape of TB through epidemiological, molecular, and clinical perspectives. The research aims to unravel the genomic intricacies of MTBC strains, by investigating the transmission dynamics of rifampicin-resistant (RR)/MDR-TB in Sierra Leone and exploring the transmission dynamics and drug resistance patterns of the sublineage 4.6.2.2 Cameroon. By shedding light on these aspects, this thesis seeks to contribute to enhanced diagnostics and more effective treatment strategies and ultimately support the global mission to eradicate TB. In the study on RR/MDR-TB in Sierra Leone, whole genome sequencing (WGS) revealed high levels of drug resistance, with one in four strains being resistant to all first-line anti-TB drugs. While no FQ resistance was detected, five strains exhibited resistance to BDQ/clofazimine (CFZ) due to mutations in the Rv0678 gene. The study also revealed a greater diversity of drug resistance mutations, including borderline INH and RIF resistance mutations, which can potentially influence treatment options. The high cluster rate of over 40% indicated ongoing transmission of RR/MDR-TB strains, contributing to the burden of RR/MDR-TB in the country. Analysis of the 238 MTBC strains revealed a high diversity of strains in Sierra Leone. The presence of six major lineages (L) of MTBC strains (L1= 4%, L2 = 9%, L3= 0.8%, L4= 62%, L5= 2.9% and L6= 21%) were identified in Sierra Leone. Mycobacterium tuberculosis (Mtb) strains constitute 56%, while Mycobacterium africanum (Maf) L6 strains, account for 21% of MDR MTBC strains, which suggest a longitudinal outbreak with specific branches exhibiting resistance to multiple drugs, including BDQ/CFZ. Despite the high diversity, strains of certain sublineages 4.1.2.1. Haarlem, 4.8 mainly T and 2.2.1 Beijing Ancestral 3 and 6.3.3 West Africa 2 were implicated in the ongoing MDR transmissions. The global population structure and phylogeography of strains of the Cameroon sublineage were also investigated using WGS. The strains were classified into eight distinct clades, with strains originating from 24 countries across Africa, Asia, Australia, and Europe. A fourth of the strains were identified as transmission strains. The strains of two clades, C.5 and C.8, exhibited high clustering rates, indicating higher transmission potential. Drug resistance was also observed, with over 10% of the strains classified as MDR. The strains remained susceptible to BDQ/CFZ, except for two strains displaying resistance. Overall, these findings contribute to a comprehensive understanding of the transmission dynamics and drug resistance patterns of MTBC strains in Sierra Leone and the sublineage 4.6.2.2 Cameroon. The clades of strains that were defined, clusters, and global distribution emphasize the role of migration in the spread of these strains locally and beyond Africa. The insights gained from this research can inform and improve TB surveillance and control measures, both within Sierra Leone, West Africa, and in other parts of the world where the Cameroon sublineage strains have been identified.
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    Mycobacterium tuberculosis infection of human macrophages
    (2022) Tazoll, Simone Christa
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    Mycobacterium tuberculosis resistance evolution
    (2025) Walz, Teresa
    With nearly half a million new multidrug resistant (MDR) tuberculosis (TB) cases estimated annually, TB is a major contributor to the current antimicrobial resistance crisis. MDR-TB is defined as an infection with a Mycobacterium tuberculosis complex (MTBC) strain resistant to the two most effective first-line drugs rifampicin (RIF) and isoniazid. To effectively address this public health crisis, it is essential to un-derstand resistance mechanisms and evolution. This will better guide the development of new antibiot-ics and treatment strategies, and avoid rapid resistance development, as seen with bedaquiline (BDQ). This work explores resistance mechanisms to one key MDR-TB treatment drug, namely BDQ, and new evolutionary medicine informed treatment strategies based on negative hysteresis. BDQ, one of the most important drugs for treating MDR-TB, is facing increasing resistance in clinical MTBC strains in several high incidence settings. Clinical MTBC strains acquire BDQ resistance through mutations in the atpE gene, which encodes the ATP synthase (primary target of BDQ), and in the Rv0678 gene, which regulates the mmpS5-mmpL5 efflux pump system. Most clinical resistance is associated with mutations in Rv0678, leading to increased expression of the efflux pump genes. In this work, RNA sequencing (RNAseq) analysis of BDQ-resistant mutants, harbouring different mutations in Rv0678 (to-tal loss-of-function mutations and reduced-function mutations), was conducted. The results revealed that efflux pump expression varied among clones, with baseline mmpS5-mmpL5 efflux pump gene ex-pression upregulated without BDQ exposure. Surprisingly, under BDQ challenge, the wild-type H37Rv strain upregulated the mmpS5-mmpL5 efflux pump to similar levels as the Rv0678 mutant clones, point-ing to other mechanisms involved in resistance development. Analysis of the transcriptional response of Rv0678 mutant clones and H37Rv at different BDQ exposure timepoints revealed a complex response indicating that resistance is mediated not by a single mechanism, but rather by an enhanced metabolic plasticity of the Rv0678 mutants, which allows them to shift to a dormant-like state under stress while maintaining some cellular functions. The second focus of this work was to explore evolution-informed treatment strategies aimed at en-hancing drug efficacy and circumvent resistance evolution by using negative hysteresis as potential mechanism in sequential treatments to limit the evolutionary potential of MTBC strains. An in vitro model was designed based on short pre-exposure with one drug, followed by main-exposure with the second drug utilizing sub-lethal concentrations which potentially induces cellular hysteresis, a phenom-enon where antibiotic effectiveness is enhanced based on the order of drug administration. Sequential exposure of MTBC reference strain H37Rv with ethambutol (EMB) followed by RIF led to a sequence-dependent reduction in bacterial load, attributed to the negative hysteresis effect, where EMB pre-exposure enhanced RIF's efficacy. RNAseq was employed to investigate the underlying mechanisms, indicating that the cellular hysteresis effect, induced by the respective drug sequence, was likely driven by a cell surface stress response and metabolic remodelling by a danK-mediated stress response. Taken together, the results obtained in this thesis contradicts common knowledge that BDQ resistance induced by Rv0678 mutations is solely conferred by upregulation of the mmpS5-mmpL5 efflux pump system only, but rather points to the role of an enhanced metabolic plasticity in antibiotic responses as important survival strategy. It also shows, that comprehensive studies based on mutant generation combined with OMICS tools are needed to understand pathogen drug response, and escape mecha-nisms. Further, to the best of our knowledge, for the first time the potential of negative hysteresis in-duced by fast drug switching for enhancing drug efficacy even at sub-minimum inhibitory concentration (MIC) conditions was observed in M. tuberculosis. This has great potential for optimizing TB treatment concepts especially for drug resistant MTBC strains, where drug options are limited and cycling thera-pies with a lower number of antibiotics significantly enhance treatment possibilities. Accordingly, evolu-tionary informed treatment strategies should be urgently further exploited.
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    Sex differences in vaccine induced immunity and protection against Mycobacterium tuberculosis
    (2025-01-24) Harikumar Parvathy, Gishnu
    Tuberculosis (TB), a disease killing over a million people per annum, shows a strong male preponderance in disease development. Although increased male affliction for TB has long been known from an epidemiological perspective, the mechanistic understanding of those differences is relatively recent. The only approved vaccine for TB, Bacillus Calmette Guérin (BCG), shows high variability in its protective efficacy – necessitating the development of effective vaccine candidates. However, whether the male-biased susceptibility to TB also applies to the efficacy of the BCG vaccine, has been scarcely explored. In the current study, a male specific failure of BCG is demonstrated in the C57BL/6 mouse model. However, two recombinant derivatives of BCG (rBCGs) - VPM1002 and BCGΔBCG1419c - were found to ameliorate this male specific vulnerability of BCG by significantly improving survival rates in males upon Mycobacterium tuberculosis (Mtb) challenge. The disparities in survival between rBCGs and BCG vaccinated males were not attributable to their ability to reduce lung colony forming units (CFUs). Further analysis revealed that BCGΔBCG1419c, used as a representative of VPM1002 and BCGΔBCG1419c, significantly enhances CD8 T cell responses 90 days post vaccination compared to BCG, specifically in males. This enhancement shows a strong positive correlation with improved survival following Mtb challenge. In addition, significant positive correlations were identified between the CD4 T cell response on day 28 post-vaccination and the CD8 T cell response on day 90 post-vaccination, as well as between the CD4 T and B cell responses on day 28 post-vaccination. The CD4 T cell response at day 28 post-vaccination also showed a significant direct correlation with survival following Mtb challenge. Lastly, 28 days post-vaccination, CD8 T cell populations in the spleen showed distinct global differences between sexes, with specific clusters varying between males and females, independent of vaccine type. In summary, the current study identified a male specific failure of BCG in the C57BL/6 mouse model of TB and the ability of rBCGs to significantly improve the protective efficacy specifically in males. The underlying differences in post-vaccine immune responses that correlate with vaccine efficacy, as well as, those differences between sexes were identified. Elucidating how sex-specific differences in CD8 T cell responses influence vaccine efficacy, as well as the potential role of CD4 T cells and B cells in the sex-specific development of different CD8 T cell populations open new avenues for future studies.
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    TB22
    (2022) Reimann, Maja

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