UK-5099

Human embryonic stem cells (hESCs) hold immense promises for regenerative medicine and exhibit two distinct pluripotency states: primed and naïve. However, metabolic regulation underlying these states remains incompletely understood. In particular, mitochondrial pyruvate oxidation in pluripotency regulation has not been documented. Here, we combined an inducible dihydrolipoamide S‐acetyltransferase ( DLAT ) knockout model and pharmacological inhibition of mitochondrial pyruvate uptake (via the mitochondrial pyruvate carrier inhibitor UK5099) to dissect the state‐specific effects of mitochondrial pyruvate oxidation in isogenic naïve and primed hESCs. Primed hESCs lacking DLAT or treated with UK5099 displayed pronounced cell death, reduced global protein acetylation levels, and transcriptional dysregulation. These defects were partially rescued by sodium acetate supplementation, implicating a reduction in acetyl‐CoA abundance as a key mechanism. Notably, a set of neural lineage genes was specifically downregulated by disrupted mitochondrial pyruvate oxidation in primed hESCs, revealing the importance of mitochondrial pyruvate oxidation–mediated acetyl‐CoA production in priming neural differentiation. In line with this, disruption of mitochondrial pyruvate oxidation impaired the differentiation process of primed hESCs towards neuroectoderm. In contrast, DLAT depletion in naïve hESCs did not affect cell growth and the naïve pluripotency state, highlighting the pluripotency state‐dependent function of mitochondrial pyruvate oxidation. Our study uncovers the pivotal roles of mitochondrial pyruvate oxidation‐mediated acetyl‐CoA production for sustaining survival and transcriptional fidelity as well as facilitating neural differentiation in primed hESCs. Moreover, we emphasize that the function of mitochondrial pyruvate oxidation in hESCs is pluripotency state‐dependent. These findings provide new cues for optimizing hESC maintenance and differentiation through targeted metabolic manipulation.

Mycobacterium abscessus (Mab), a nontuberculous mycobacterium, is increasing in prevalence worldwide and causes treatment-refractory pulmonary diseases. However, how Mab rewires macrophage energy metabolism to facilitate its survival is poorly understood. We compared the metabolic profiles of murine bone marrow-derived macrophages (BMDMs) infected with smooth (S)- and rough (R)-type Mab using extracellular flux technology. Mab infection shifted BMDMs towards a more energetic phenotype, marked by increased oxidative phosphorylation (OXPHOS) and glycolysis, with a significantly greater enhancement in OXPHOS. This metabolic adaptation was characterized by enhanced ATP production rates, particularly in cells infected with S-type Mab, highlighting OXPHOS as a key energy source. Notably, Mab infection also modulated mitochondrial substrate preferences, increasing fatty acid oxidation capabilities while revealing significant changes in glutamine dependency and flexibility. R-type Mab infections exhibited a marked decrease in glutamine reliance but enhanced metabolic flexibility and capacity. Furthermore, targeting metabolic pathways related to glutamine and fatty acid oxidation exacerbated Mab growth within macrophages, suggesting these pathways play a protective role against infection. These insights advance our understanding of Mab's impact on host cell metabolism and propose a novel avenue for therapeutic intervention. By manipulating host mitochondrial metabolism, we identify a potential host-directed therapeutic strategy against Mab, offering a promising alternative to conventional treatments beleaguered by drug resistance. This study underscores the importance of exploring metabolic interventions to combat Mab infection, paving the way for innovative approaches in the fight against this formidable pathogen.