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Abstract The spaceflight environment imposes risks for maintaining a healthy skin function as the observed delayed wound healing can contribute to increased risks of infection. To counteract delayed wound healing in space, a better understanding of the fibroblasts’ reaction to altered gravity levels is needed. In this paper, we describe experiments that were carried out at the Large Diameter Centrifuge located in ESA-ESTEC as part of the ESA Academy 2021 Spin Your Thesis! Campaign. We exposed dermal fibroblasts to a set of altered gravity levels, including transitions between simulated microgravity and hypergravity. The addition of the stress hormone cortisol to the cell culture medium was done to account for possible interaction effects of gravity and cortisol exposure. Results show a main impact of cortisol on the secretion of pro-inflammatory cytokines as well as extracellular matrix proteins. Altered gravity mostly induced a delay in cellular migration and changes in mechanosensitive cell structures. Furthermore, 20 × g hypergravity transitions induced changes in nuclear morphology. These findings provide insights into the effect of gravity transitions on the fibroblasts’ function related to wound healing, which may be useful for the development of countermeasures.

Multidrug resistance necessitates novel approaches to treating bacterial infections. Here, the authors apply their high-throughput screening and in silico prediction approaches to show that host receptor tyrosine kinases are good targets for host-directed therapies against intracellular bacteria.

One-third of the world population is infected with Mycobacterium tuberculosis and multi-drug resistant strains are rapidly evolving. The noticeable absence of a whole organism high-throughput screening system for studying the progression of tuberculosis is fast becoming the bottleneck in tuberculosis research. We successfully developed such a system using the zebrafish Mycobacterium marinum infection model, which is a well-characterized model for tuberculosis progression with biomedical significance, mimicking hallmarks of human tuberculosis pathology. Importantly, we demonstrate the suitability of our system to directly study M. tuberculosis, showing for the first time that the human pathogen can propagate in this vertebrate model, resulting in similar early disease symptoms to those observed upon M. marinum infection. Our system is capable of screening for disease progression via robotic yolk injection of early embryos and visual flow screening of late-stage larvae. We also show that this system can reliably recapitulate the standard caudal vein injection method with a throughput level of 2,000 embryos per hour. We additionally demonstrate the possibility of studying signal transduction leading to disease progression using reverse genetics at high-throughput levels. Importantly, we use reference compounds to validate our system in the testing of molecules that prevent tuberculosis progression, making it highly suited for investigating novel anti-tuberculosis compounds in vivo.

Tuberculosis (TB) is an escalating global health problem and improved vaccines against TB are urgently needed. HLA-E restricted responses may be of interest for vaccine development since HLA-E displays very limited polymorphism (only 2 coding variants exist), and is not down-regulated by HIV-infection. The peptides from Mycobacterium tuberculosis (Mtb) potentially presented by HLA-E molecules, however, are unknown. Here we describe human T-cell responses to Mtb-derived peptides containing predicted HLA-E binding motifs and binding-affinity for HLA-E. We observed CD8(+) T-cell proliferation to the majority of the 69 peptides tested in Mtb responsive adults as well as in BCG-vaccinated infants. CD8(+) T-cells were cytotoxic against target-cells transfected with HLA-E only in the presence of specific peptide. These T cells were also able to lyse M. bovis BCG infected, but not control monocytes, suggesting recognition of antigens during mycobacterial infection. In addition, peptide induced CD8(+) T-cells also displayed regulatory activity, since they inhibited T-cell proliferation. This regulatory activity was cell contact-dependent, and at least partly dependent on membrane-bound TGF-beta. Our results significantly increase our understanding of the human immune response to Mtb by identification of CD8(+) T-cell responses to novel HLA-E binding peptides of Mtb, which have cytotoxic as well as immunoregulatory activity.