Biology subjects

Wouters, A.

Publications and source records attributed to Wouters, A..

3 recordsLinked to original sources

bioRxiv2026

Menaquinone depletion resensitises bedaquiline-resistant tuberculosis

Tuberculosis remains a leading cause of global mortality, and rising bedaquiline resistance threatens the effectiveness of current drug-resistant treatment regimens. Bedaquiline resistance typically arises through mutations in Rv0678 that upregulate drug efflux and confer cross-resistance to multiple drug classes. Here, we identify and optimise a chemical series targeting MenG, a central enzyme in the menaquinone biosynthesis pathway, yielding potent bactericidal inhibitors with in vivo efficacy. Strikingly, MenG inhibition restored bedaquiline susceptibility in efflux-mediated resistant strains, an effect confirmed in vivo where combination therapy achieved a 99.8% reduction in bacterial burden compared with bedaquiline alone. Potentiation also extended to pretomanid and other key agents. Disruption of upstream menaquinone and shikimate pathway enzymes produced similar resensitisation, establishing these pathways as tractable targets for restoring drug susceptibility in Mycobacterium tuberculosis. These findings provide a novel strategy to overcome bedaquiline resistance and strengthen future regimens for efflux-mediated drug-resistant tuberculosis.

microbiology↗

bioRxiv2025

HIF isoforms contribute distinctly during human NK cell activation

Hypoxia-inducible factors (HIFs) are critical transcriptional regulators that enable cellular adaptation to low oxygen environments. Natural killer (NK) cells are key effectors of innate immunity which frequently operate in hypoxic tissues during viral infection and tumor surveillance. In addition, HIF also play a role in NK cells beyond hypoxic adaptation. However, the distinct and overlapping roles of HIF-1 and HIF-2 in NK cell biology remain incompletely understood. In this study, we investigated the contribution of HIF-1 and HIF-2 to NK cell effector functioning in normoxia using pharmacological inhibition. When HIF-1 was inhibited, we observed a pronounced decline in cytotoxicity as well as IFN{gamma} and TNF production, but not granzyme B, accompanied by elevated mitochondrial reactive oxygen species. In contrast, HIF-2 did not alter these functions, nor did pan-HIF stabilization. These findings indicate a differential role of HIF-1 and HIF-2 in shaping NK cell responses in normoxia, at least during the acute activation phase as investigated here. Still, more mechanistic and contextual insights into the role of HIF isoforms in NK cells is warranted for future therapeutic applications.

immunology↗

bioRxiv2025

DRP1 depletion protects NK cells against hypoxia-induced dysfunction

Hypoxia within the tumor microenvironment poses a major barrier to the efficacy of NK cell-based immunotherapies for solid tumors. In this study, we investigated the influence of hypoxia on NK cell function and mitochondria. We found that hypoxia reduced NK cell cytotoxicity, mitochondrial content, and membrane potential, while increasing mtROS and inducing broad transcriptional changes in metabolic and stress response pathways. CAR engineering with CD70 and IL-15, while designed to enhance persistence and metabolic fitness, did not prevent hypoxia-induced impairment. Given the mitochondrial disruption, we then explored whether DRP1 ablation could mitigate hypoxia-induced dysfunction. Pharmacological inhibition of DRP1 restored mitochondrial content and cytotoxic function. To confirm the role of DRP1, we generated CRISPR-Cas9-mediated DRP1 KO NK cells, which preserved mitochondrial load and membrane potential under hypoxia. When armed with CD70-CAR-IL-15, DRP1KO cells retained cytotoxic activity under hypoxic conditions. These findings show that DRP1 inactivation can support NK cell function in hypoxic environments, and that metabolic engineering may enhance CAR NK cell efficacy in solid tumors. Graphical abstractNK cells become dysfunctional in hypoxic conditions, while DRP1KO NK cells retain their function. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=149 SRC="FIGDIR/small/661011v2_ufig1.gif" ALT="Figure 1"> View larger version (54K): org.highwire.dtl.DTLVardef@2c3a96org.highwire.dtl.DTLVardef@1ba7d20org.highwire.dtl.DTLVardef@6ceeecorg.highwire.dtl.DTLVardef@1b9e0ca_HPS_FORMAT_FIGEXP M_FIG C_FIG

immunology↗