Biology subjects

Pawlik, A.

Publications and source records attributed to Pawlik, A..

5 recordsLinked to original sources

bioRxiv2025

Improved Immune Responses and Tuberculosis Protection by Aerosol Vaccination with recombinant BCG expressing ESX-1 from Mycobacterium marinum

The currently licensed anti-tuberculosis (TB) vaccine, Mycobacterium bovis BCG, provides limited protection against pulmonary TB in adolescents and adults, the main cause of TB transmission and mortality. To obtain an improved BCG-based vaccine candidate with increased immune signaling but still low virulence, we have previously generated a recombinant BCG strain named BCG::ESX-1Mmar, which is heterologously expressing ESX-1 functions of Mycobacterium marinum and thereby modulates the host innate immune responses via phagosomal rupture-associated induction of type I interferon production and enhanced inflammasome activity, leading to superior protection against TB disease in murine infection models. As protection may also vary with the route of vaccination, here, we have explored aerosol vaccination relative to subcutaneous vaccination, using BCG Pasteur and BCG::ESX-1Mmar. We found that mice vaccinated via the aerosol route with BCG Pasteur or BCG::ESX-1Mmar both yielded higher frequencies of CD4+ and CD8+ T effector memory (TEM) cells in the lungs compared to subcutaneously immunised mice, whereas comparable poly-functional Th1 (IL-2, TNF- and IFN-{gamma}) cytokine-producing subsets were observed in the spleens of all vaccinated mice. Significantly higher IL-17 responses without severe lung pathology were seen in the lungs of aerosol-vaccinated mice associated to local and transient inflammatory cytokine responses and immune cell infiltrations. Aerosol vaccination also elicited high amounts of humoral IgG and IgM responses in the bronchoalveolar lavage fluid and induced substantial lung CD69+ CD103+ T resident memory (TRM) cells, containing both CD4+ and CD8+ T subsets, in the airways of immunised mice, whereas this was not the case for subcutaneous vaccination. These effects led to significant improved protection against M. tuberculosis and reduced lung pathology in aerosol-vaccinated mice compared to subcutaneously vaccinated mice. Moreover, BCG::ESX-1Mmar induced enhanced T-cell immunity and superior protection compared to parental BCG Pasteur for both vaccination routes and thereby represents an interesting candidate for developing improved vaccination strategies against TB. Author summaryAnti-tuberculosis vaccine efficacy is influenced by multiple parameters, including the immunogenicity of the vaccine strain, the type of preclinical host model used, and the route of vaccination. Given recent advances in the field of mucosal vaccination, in the current study we were particularly interested to explore and compare aerosol-based vaccination with standard subcutaneous vaccination in a C57BL/6J mouse model using our recently developed recombinant BCG::ESX-1Mmar vaccine candidate in comparison with parental BCG Pasteur. Our results show that in this setting the protective efficacy of mucosal vaccination was superior to subcutaneous vaccination for both vaccine strains, whereby the use of BCG::ESX-1Mmar induced additional benefits in terms of bacterial load reduction compared to standard BCG Pasteur. Taken together, we propose that aerosol vaccination using BCG::ESX-1Mmar as live-attenuated vaccine candidate is a promising and powerful combination for obtaining improved protection against an M. tuberculosis challenge, a concept that can now be tested in other animal models in a perspective of a putative clinical trial.

microbiology↗

bioRxiv2023

An oxadiazole-based compound potentiates anti- tuberculosis treatment by increasing host resistance via zinc poisoning

Anti-tuberculosis drugs, mostly developed over 60 years ago, combined with a poorly effective vaccine, have failed to eradicate tuberculosis. More worryingly, multi-resistant strains of Mycobacterium tuberculosis are constantly emerging. Innovative strategies are thus urgently needed to improve tuberculosis treatment. Recently, host-directed therapy has emerged as a promising strategy to be used in adjunct with existing or future antibiotics, by improving innate immunity or limiting immunopathology. Here, using high content imaging, we identified novel 1,2,4-oxadiazole-based compounds, that allow human macrophages to control MTB replication. Genome-wide gene expression analysis revealed that these molecules induced zinc remobilization inside cells, resulting in bacterial zinc intoxication. More importantly, we also demonstrated that, upon treatment with these novel compounds, M. tuberculosis became even more sensitive to anti-tuberculosis drugs, in vitro and in vivo, in a mouse model of tuberculosis. Manipulation of heavy metal homeostasis holds thus great promise to be exploited to develop host-directed therapeutic interventions.

microbiology↗

bioRxiv2021

De novo synthesized polyunsaturated fatty acids operate as both host immunomodulators and nutrients for Mycobacterium tuberculosis

Successful control of Mycobacterium tuberculosis (Mtb) infection by macrophages relies on immunometabolic reprogramming, where the role of fatty acids (FAs) remains poorly understood. Recent studies unraveled Mtbs capacity to acquire saturated and monounsaturated FAs via the Mce1 importer. However, upon activation macrophages produce polyunsaturated FAs (PUFAs), mammal-specific FAs mediating the generation of key immunomodulatory eicosanoids. Here, we asked whether de novo synthesis of PUFAs is modulated in Mtb-infected macrophages and benefits host or pathogen. Quantitative lipidomics revealed that Mtb infection activates the early PUFA biosynthetic pathway for production of eicosanoids. While PUFA synthesis blockade significantly impaired the inflammatory and antimicrobial responses of infected macrophages, it had no effect on Mtb growth in vivo. Using a click-chemistry approach, we found that Mtb efficiently imports PUFAs of the {omega}6 subset via Mce1 in axenic culture, including the eicosanoid precursor arachidonic acid (AA). Notably, Mtb preferentially internalized AA over all other FAs within infected macrophages, but here Mtbs import of AA was largely Mce1-independent and correlated with elevated AA uptake by host cells. Together, these findings reveal AA as a major FA substrate for intracellular Mtb. They suggest that Mtbs hijacking of host-derived AA may counteract its stimulatory effect on anti-mycobacterial immune responses.

immunology↗

bioRxiv2019

Mycobacterium abscessus virulence traits unraveled by transcriptomic profiling in amoeba and macrophages

Free-living amoebae might represent an evolutionary niche. In order to get more insights into the potential amoebal training ground for Mycobacterium abscessus, we characterized its full transcriptome in amoeba (Ac) and macrophages (M{varphi}), as well as the Mycobacterium chelonae intra-Ac transcriptome for comparison. Up-regulated genes in Ac allowed M. abscessus to resist environmental stress and induce defense mechanisms, as well as showing switch from carbohydrate carbon sources to fatty acid metabolism. Eleven genes implicated in the adaptation to intracellular stress, were mutated, with all but one confirmed to be involved in M. abscessus intra-M{varphi} survival. Cloning two of these genes in M. chelonae increased its intra-M{varphi} survival. One mutant was particularly attenuated in M{varphi} that corresponded to the deletion of an Eis N-acetyl transferase protein (MAB_4532c). Taken together, M. abscessus transcriptomes revealed the intracellular lifestyle of the mycobacteria, with Ac largely contributing to the enhancement of M. abscessus intra-M{varphi} survival.

microbiology↗

bioRxiv2016

A meta-analysis of bioinformatics softwarebenchmarks reveals that publication-bias undulyinfluences software accuracy

BackgroundComputational biology provides widely used and powerful software tools for testing and making inferences about biological data. In the face of rapidly increasing volumes of data, heuristic methods that trade software speed for accuracy may be employed. We are have studied these trade-offs using the results of a large number of independent software benchmarks, and evaluated whether external factors are indicative of accurate software. MethodWe have extracted accuracy and speed ranks from independent benchmarks of different bioinformatic software tools, and evaluated whether the speed, author reputation, journal impact, recency and developer efforts are indicative of accuracy. ResultsWe found that software speed, author reputation, journal impact, number of citations and age are all unreliable predictors of software accuracy. This is unfortunate because citations, author and journal reputation are frequently cited reasons for selecting software tools. However, GitHub-derived records and high version numbers show that the accurate bioinformatic software tools are generally the product of many improvements over time, often from multiple developers. DiscussionWe also find that the field of bioinformatics has a large excess of slow and inaccurate software tools, and this is consistent across many sub-disciplines. Meanwhile, there are few tools that are middle-of-road in terms of accuracy and speed trade-offs. We hypothesise that a form of publication-bias influences the publication and development of bioinformatic software. In other words, software that is intermediate in terms of both speed and accuracy may be difficult to publish - possibly due to author, editor and reviewer practices. This leaves an unfortunate hole in the literature as the ideal tools may fall into this gap. For example, high accuracy tools are not always useful if years of CPU time are required, while high speed is not useful if the results are also inaccurate.

bioinformatics↗