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McClain, C. J.

Publications and source records attributed to McClain, C. J..

2 recordsLinked to original sources

Dietary fructose promotes MASH/HCC progression through enhanced intestinal HIF-2α-dependent iron absorption

Dietary fructose is a major risk factor driving the progression of metabolic dysfunction-associated steatohepatitis (MASH) and hepatocellular carcinoma (HCC). However, the underlying fructose-induced nutrient-sensing pathway remains unclear. Here, we report that fructose facilitates iron absorption through the (Ketohexokinase) KHK/PKM2/HIF-2 axis, driving MASH and HCC development. Fructose aberrantly stabilizes intestinal HIF-; this effect is abrogated by a KHK inhibitor and genetic Khk deletion. Mechanistically, fructose-induced metabolic reprogramming drives glutamine-dependent oxidative phosphorylation, leading to HIF- stabilization, which is mediated by pyruvate kinase M2 (PKM2). A selective PKM2 inhibitor rescues reduced intestinal HIF- stability in Khk-deficient mice. Furthermore, dietary fructose increases plasma iron levels. Conversely, Khk-deficient mice exhibit spontaneous systemic iron deficiency, characterized by hypochromic anemia. Moreover, Khk deficiency inhibits iron absorption in a HIF-2-dependent manner. Finally, fructose promotes MASH and HCC progression in an iron-dependent manner. This study reveals a unique, therapeutically targetable nutrient-sensing pathway utilized by dietary fructose. In briefMitchell et al. demonstrate that fructose consumption increases plasma iron levels, while KHK deficiency inhibits iron absorption in a HIF-2-dependent manner. Mechanistically, dietary fructose-induced metabolic reprogramming aberrantly stabilizes intestinal HIF-, which is mediated by PKM2. Fructose promotes MASH and HCC progression in an iron-dependent manner. HighlightsO_LIFructose aberrantly stabilizes intestinal HIF- C_LIO_LIKHK is required for intestinal HIF- stability C_LIO_LIKHK deficiency inhibits iron absorption in a HIF-2-dependent manner C_LIO_LIDietary fructose promotes MASH and HCC progression in an iron-dependent manner C_LI

physiology↗

Gut Microbial Trimethylamine is Elevated in Alcohol-Associated Hepatitis and Contributes to Ethanol-Induced Liver Injury in Mice

BACKGROUNDThere is mounting evidence that microbes resident in the human intestine contribute to diverse alcohol-associated liver diseases (ALD) including the most deadly form known as alcohol-associated hepatitis (AH). However, mechanisms by which gut microbes synergize with excessive alcohol intake to promote liver injury are poorly understood. Furthermore, whether drugs that selectively target gut microbial metabolism can improve ALD has never been tested. METHODSWe used liquid chromatography tandem mass spectrometry to quantify the levels of microbe and host choline co-metabolites in healthy controls and AH patients, finding elevated levels of the microbial metabolite trimethylamine (TMA) in AH. In subsequent studies, we treated mice with non-lethal bacterial choline TMA lyase (CutC/D) inhibitors to blunt gut microbe-dependent production of TMA in the context of chronic ethanol administration. Indices of liver injury were quantified by complementary RNA sequencing, biochemical, and histological approaches. In addition, we examined the impact of ethanol consumption and TMA lyase inhibition on gut microbiome structure via 16S rRNA sequencing. RESULTSWe show the gut microbial choline metabolite trimethylamine (TMA) is elevated in AH patients and correlates with reduced hepatic expression of the TMA oxygenase flavin-containing monooxygenase 3 (FMO3). Provocatively, we find that small molecule inhibition of gut microbial CutC/D activity protects mice from ethanol-induced liver injury. CutC/D inhibitor-driven improvement in ethanol-induced liver injury is associated with distinct reorganization of the gut microbiome and host liver transcriptome. CONCLUSIONSThe microbial metabolite TMA is elevated in patients with AH, and inhibition of TMA production from gut microbes can protect mice from ethanol-induced liver injury.

biochemistry↗