Biology subjects

Yoon, C. E.

Publications and source records attributed to Yoon, C. E..

3 recordsLinked to original sources

bioRxiv2026

Microbiome-Targeted Reduction of Circulating Trimethylamine N-Oxide Mitigates Ischemic Stroke Risk

Elevated plasma trimethylamine N-oxide (TMAO) is an independent predictor of major adverse cardiovascular events and ischemic stroke. While inhibition of microbial TMA production has been explored, concerns regarding off-target effects and limited efficacy in complex microbial ecosystems have hindered clinical translation. Here, we report a microbiome-based therapeutic strategy based on the direct enzymatic degradation of intestinal TMA by Paracoccus aminovorans BM109. Through targeted screening, we identified BM109 as a commensal strain harboring a comprehensive set of enzymes capable of metabolizing TMA and TMAO into non-toxic end products under both aerobic and anaerobic conditions. In a chronic high-choline diet murine model, oral administration of BM109 resulted in a 38% reduction in systemic TMAO levels. In a rat model of transient middle cerebral artery occlusion (tMCAO), short-term pre-treatment reduced cerebral infarct size by 58% and significantly improved neurological outcomes. These effects were accompanied by favorable safety observations, including the absence of hemolytic activity and intestinal tissue damage. Collectively, our findings establish BM109 as a promising live biotherapeutic product that targets the gut microbiome-host metabolic axis. By reducing the systemic TMAO burden, BM109 represents a potential strategy for modulating cardiometabolic and cerebrovascular risk.

microbiology↗

bioRxiv2024

Anemia and tissue hypoxia are major determinants of malarial hypelactatemia

Hyperlactatemia, a key marker of severe malaria, is closely linked to increased mortality, though the exact mechanisms remain unclear. It may result from increased lactate production due to tissue hypoxia or reduced lactate clearance from organ dysfunction. This study used Plasmodium yoelii 17XL (Py17XL) murine model of severe malaria, which closely mimics hyperlactatemia seen in human cases, to investigate the contributions of severe anemia and infection-related organ dysfunction to hyperlactatemia. Non-infectious anemia models were also included for comparison. Anemia was found to elevate lactate in both malaria-infected and non-infectious models, but Py17XL infected mice showed higher lactate levels, indicating that anemia alone doesnt fully explain hyperlactatemia. Evidence of tissue hypoxia, particularly in the liver, kidney, and gut, was seen with hypoxyprobe staining and upregulated hypoxia-inducible factor 1-alpha (HIF-1), suggesting that hypoxia drives increased glycolysis and lactate production. Impaired lactate clearance may also play a role, as infected mice showed signs of liver and kidney dysfunction accompanied by reduced clearance of 13C3-labeled sodium-L-Lactate. Whole blood transfusion combined with artesunate significantly improved lactate clearance compared to artesunate alone, underscoring the importance of addressing anemia in treatment. A link between intestinal damage and hyperlactatemia was suggested by correlations between trefoil factor 3 (TFF3), a marker of gut injury, and lactate levels in human samples. Our findings highlight the multifactorial origin of hyperlactatemia in malaria, driven primarily by anemia and tissue hypoxia, pointing to the need for therapies targeting both aspects to reduce mortality in severe cases.

pathology↗

bioRxiv2024

Histone lactylation: a new epigenetic mark in the malaria parasite Plasmodium

Epigenetic processes play important roles in the biology of the malaria parasite Plasmodium falciparum. Here, we characterised a new epigenetic mark, histone lactylation, recently discovered in humans: it was found in two human malaria parasites, P. falciparum and P. knowlesi, and also in vivo in two rodent malaria models. Histones were lactylated rapidly in response to elevated lactate levels, and rapidly delactylated when lactate levels fell. Thus, this mark is well-placed to act as a metabolic sensor, since severe falciparum malaria characteristically leads to hyperlactataemia. Mass spectrometry showed that lysines on several parasite histones could be lactylated, as well as many non-histone chromatin proteins. Histone lactylation was less abundant and less inducible in P. knowlesi than P. falciparum, suggesting that P. falciparum may have evolved particular epigenetic responses to this characteristic feature of its pathology. Finally, in the rodent model P. yoelii, hyperlactataemia correlated with parasite transcriptomic programmes that suggested metabolic dormancy.

microbiology↗