2022
Q-Flux: A method to assess hepatic mitochondrial succinate dehydrogenase, methylmalonyl-CoA mutase, and glutaminase fluxes in vivo
Hubbard B, LaMoia T, Goedeke L, Gaspar R, Galsgaard K, Kahn M, Mason G, Shulman G. Q-Flux: A method to assess hepatic mitochondrial succinate dehydrogenase, methylmalonyl-CoA mutase, and glutaminase fluxes in vivo. Cell Metabolism 2022, 35: 212-226.e4. PMID: 36516861, PMCID: PMC9887731, DOI: 10.1016/j.cmet.2022.11.011.Peer-Reviewed Original ResearchDistinct subcellular localisation of intramyocellular lipids and reduced PKCε/PKCθ activity preserve muscle insulin sensitivity in exercise-trained mice
Gaspar R, Lyu K, Hubbard B, Leitner B, Luukkonen P, Hirabara S, Sakuma I, Nasiri A, Zhang D, Kahn M, Cline G, Pauli J, Perry R, Petersen K, Shulman G. Distinct subcellular localisation of intramyocellular lipids and reduced PKCε/PKCθ activity preserve muscle insulin sensitivity in exercise-trained mice. Diabetologia 2022, 66: 567-578. PMID: 36456864, PMCID: PMC11194860, DOI: 10.1007/s00125-022-05838-8.Peer-Reviewed Original ResearchConceptsProtein kinase CsSubcellular compartmentsDistinct subcellular localisationMuscle insulin sensitivityMultiple subcellular compartmentsInsulin receptor kinaseNovel protein kinase CsActivation of PKCεSubcellular localisationPKCθ translocationReceptor kinasePlasma membraneSubcellular distributionTriacylglycerol contentCrucial pathwaysIntramuscular triacylglycerol contentRC miceDiacylglycerolConclusions/interpretationThese resultsPKCεPM compartmentPhosphorylationMuscle triacylglycerol contentSkeletal muscleRecent findingsMetformin, phenformin, and galegine inhibit complex IV activity and reduce glycerol-derived gluconeogenesis
LaMoia TE, Butrico GM, Kalpage HA, Goedeke L, Hubbard BT, Vatner DF, Gaspar RC, Zhang XM, Cline GW, Nakahara K, Woo S, Shimada A, HĂĽttemann M, Shulman GI. Metformin, phenformin, and galegine inhibit complex IV activity and reduce glycerol-derived gluconeogenesis. Proceedings Of The National Academy Of Sciences Of The United States Of America 2022, 119: e2122287119. PMID: 35238637, PMCID: PMC8916010, DOI: 10.1073/pnas.2122287119.Peer-Reviewed Original ResearchConceptsGlucose-lowering effectPlasma glucose concentrationComplex I activityHepatic gluconeogenesisType 2 diabetes mellitusGlucose concentrationGlycerol-3-phosphate dehydrogenase activityI activityDiabetes mellitusSelective inhibitionMetforminInhibitionRelevant concentrationsGluconeogenesisPhenforminVivoMost studiesDehydrogenase activityGalegineMellitus
2025
Liver lipid droplet cholesterol content is a key determinant of metabolic dysfunction–associated steatohepatitis
Sakuma I, Gaspar R, Nasiri A, Dufour S, Kahn M, Zheng J, LaMoia T, Guerra M, Taki Y, Kawashima Y, Yimlamai D, Perelis M, Vatner D, Petersen K, Huttasch M, Knebel B, Kahl S, Roden M, Samuel V, Tanaka T, Shulman G. Liver lipid droplet cholesterol content is a key determinant of metabolic dysfunction–associated steatohepatitis. Proceedings Of The National Academy Of Sciences Of The United States Of America 2025, 122: e2502978122. PMID: 40310463, DOI: 10.1073/pnas.2502978122.Peer-Reviewed Original ResearchConceptsCholine-deficient l-amino acid-defined high-fat dietBempedoic acidLiver fibrosisLiver diseaseL-amino acid-defined high-fat dietAdvanced liver diseaseCholesterol contentHSD17B13 variantsHigh-fat dietTotal liver cholesterol contentTreated miceActivate signaling pathwaysVariant rs738409Liver cholesterol contentLiver lipidsFibrotic responsePromote inflammationTherapeutic approachesSteatotic liver diseaseDietary cholesterol supplementationFibrosisHuman liver samplesI148MAntisense oligonucleotidesProgressive formDeterminants of increased muscle insulin sensitivity of exercise-trained versus sedentary normal weight and overweight individuals
Pesta D, Anadol-Schmitz E, Sarabhai T, Kamp Y, Gancheva S, Trinks N, Zaharia O, Mastrototaro L, Lyu K, Habets I, Kamp-Bruls Y, Dewidar B, Weiss J, Schrauwen-Hinderling V, Zhang D, Gaspar R, Strassburger K, Kupriyanova Y, Al-Hasani H, Szendroedi J, Schrauwen P, Phielix E, Shulman G, Roden M. Determinants of increased muscle insulin sensitivity of exercise-trained versus sedentary normal weight and overweight individuals. Science Advances 2025, 11: eadr8849. PMID: 39742483, PMCID: PMC11691647, DOI: 10.1126/sciadv.adr8849.Peer-Reviewed Original ResearchConceptsOverweight-to-obeseNormal weightEndurance-trained humansMuscle mitochondrial contentAthlete's paradoxTrained athletesExercise-trainedOverweight individualsAthletesObesity subtypesObservational studyIntramyocellular triglyceride accumulationInsulin sensitivityHigher insulin sensitivityMitochondrial contentIncreased insulin sensitivityMuscleFemale individualsIndividualsInsulin resistanceObesityMitochondrial partitioningIncreased calpainNPKC activityProtein kinase C
2024
SGLT2 inhibition alters substrate utilization and mitochondrial redox in healthy and failing rat hearts
Goedeke L, Ma Y, Gaspar R, Nasiri A, Lee J, Zhang D, Galsgaard K, Hu X, Zhang J, Guerrera N, Li X, LaMoia T, Hubbard B, Haedersdal S, Wu X, Stack J, Dufour S, Butrico G, Kahn M, Perry R, Cline G, Young L, Shulman G. SGLT2 inhibition alters substrate utilization and mitochondrial redox in healthy and failing rat hearts. Journal Of Clinical Investigation 2024, 134: e176708. PMID: 39680452, PMCID: PMC11645152, DOI: 10.1172/jci176708.Peer-Reviewed Original ResearchConceptsSodium-glucose cotransporter type 2Heart failureKetone oxidationGas chromatography-mass spectrometryFatty acid oxidationLeft ventricular ejection fractionReduced myocardial oxidative stressVentricular ejection fractionKetone supplementationWeeks of treatmentMyocardial oxidative stressDecreased pyruvate oxidationInduce heart failurePlasma glucose levelsIn vivo effectsSGLT2i treatmentEjection fractionAssociated with improvementsAwake ratsSGLT2 inhibitionCardioprotective benefitsLiquid chromatography-tandem mass spectrometryPlasma ketonesRates of ketonizationChromatography-tandem mass spectrometryCeramide synthesis inhibitors prevent lipid-induced insulin resistance through the DAG-PKCε-insulin receptorT1150 phosphorylation pathway
Xu W, Zhang D, Ma Y, Gaspar R, Kahn M, Nasiri A, Murray S, Samuel V, Shulman G. Ceramide synthesis inhibitors prevent lipid-induced insulin resistance through the DAG-PKCε-insulin receptorT1150 phosphorylation pathway. Cell Reports 2024, 43: 114746. PMID: 39302831, DOI: 10.1016/j.celrep.2024.114746.Peer-Reviewed Original ResearchLipid-induced hepatic insulin resistanceHepatic insulin resistancePhosphorylation pathwayAntisense oligonucleotidesCeramide synthesis inhibitorsLipid-induced insulin resistanceMyriocin treatmentCeramide synthesisDihydroceramide desaturaseInsulin resistanceHepatic ceramideMyriocinCeramideCeramide contentInsulin-sensitizing effectsPhosphorylationHepatic insulin sensitivityPathwaySynthetic pathwayDES1Glucose productionSynthesis inhibitorDGAT2DesaturaseInhibitionEffect of Weight Loss on Skeletal Muscle Bioactive Lipids in People With Obesity and Type 2 Diabetes.
Petersen M, Yoshino M, Smith G, Gaspar R, Kahn M, Samovski D, Shulman G, Klein S. Effect of Weight Loss on Skeletal Muscle Bioactive Lipids in People With Obesity and Type 2 Diabetes. Diabetes 2024, 73: 2055-2064. PMID: 39264820, PMCID: PMC11579410, DOI: 10.2337/db24-0083.Peer-Reviewed Original ResearchMuscle insulin sensitivitySkeletal muscle insulin sensitivityType 2 diabetesEffects of weight lossInsulin sensitivityWeight lossWeight loss-induced improvementWhole-body insulin sensitivityObesityGlucose tracer infusionAssociated with changesHyperinsulinemic-euglycemic clamp procedureCeramide contentSn-1,2-DAGMuscleSmall molecule inhibition of glycogen synthase I reduces muscle glycogen content and improves biomarkers in a mouse model of Pompe disease
Gaspar R, Sakuma I, Nasiri A, Hubbard B, LaMoia T, Leitner B, Tep S, Xi Y, Green E, Ullman J, Petersen K, Shulman G. Small molecule inhibition of glycogen synthase I reduces muscle glycogen content and improves biomarkers in a mouse model of Pompe disease. AJP Endocrinology And Metabolism 2024, 327: e524-e532. PMID: 39171753, PMCID: PMC11482269, DOI: 10.1152/ajpendo.00175.2024.Peer-Reviewed Original ResearchGAA-KO miceMouse model of Pompe diseaseModel of Pompe diseasePompe diseaseMetabolic dysregulationRegular chowMouse modelSmall molecule inhibitionInsulin sensitivityReduced spontaneous activityGroups of male miceEnzyme acid alpha-glucosidaseProgressive muscle weaknessImprove metabolic dysregulationSynthase IWhole-body insulin sensitivityAcid alpha-glucosidaseImproved glucose toleranceIncreased AMPK phosphorylationWT miceAbnormal accumulation of glycogenGlycogen storage disorderMale miceSpontaneous activityImproved biomarkers1571-P: CIDEB and CGI-58 Regulate Liver Lipid Droplet Size with Cholesterol Content, Linking to Inflammation and Fibrosis in Metabolic Dysfunction–Associated Steatohepatitis
SAKUMA I, GASPAR R, NASIRI A, KAHN M, ZHENG J, GUERRA M, YIMLAMAI D, MURRAY S, PERELIS M, BARNES W, VATNER D, PETERSEN K, SAMUEL V, SHULMAN G. 1571-P: CIDEB and CGI-58 Regulate Liver Lipid Droplet Size with Cholesterol Content, Linking to Inflammation and Fibrosis in Metabolic Dysfunction–Associated Steatohepatitis. Diabetes 2024, 73 DOI: 10.2337/db24-1571-p.Peer-Reviewed Original ResearchLipid droplet sizeCGI-58Choline-deficient l-amino acid-defined high-fat dietGlycerol-3-phosphate acyltransferaseAntisense oligonucleotidesComparative gene identification-58Glycerol-3-phosphateLoss of function mutationsLipid droplet morphologyExpression of CGI-58Liver inflammationCidebCholesterol contentFunction mutationsL-amino acid-defined high-fat dietComplications of type 2 diabetesMolecular mechanismsDevelopment of liver inflammationMacrophage crown-like structuresType 2 diabetesHigh-fat dietCrown-like structuresASO treatmentGPAMKnockdown292-OR: Coenzyme A Synthase Knockdown Alleviates Metabolic Dysfunction–Associated Steatohepatitis via Decreasing Cholesterol in Liver Lipid Droplets
SAKUMA I, GASPAR R, NASIRI A, KAHN M, GUERRA M, YIMLAMAI D, MURRAY S, PERELIS M, BARNES W, VATNER D, PETERSEN K, SAMUEL V, SHULMAN G. 292-OR: Coenzyme A Synthase Knockdown Alleviates Metabolic Dysfunction–Associated Steatohepatitis via Decreasing Cholesterol in Liver Lipid Droplets. Diabetes 2024, 73 DOI: 10.2337/db24-292-or.Peer-Reviewed Original ResearchCholine-deficient l-amino acid-defined high-fat dietAccumulation of cholesterolMRNA expressionPlasma ALTL-amino acid-defined high-fat dietProtective effectLiver lipid dropletsType 2 diabetesPotential therapeutic approachHigh-fat dietDecreased plasma ALTFibrosis markersFree cholesterol accumulationLipid dropletsLiver inflammationDay 1Macrophage markersHepatic inflammationMouse modelMarker expressionTherapeutic approachesDay 2Day 3Day 7Fibrosis1577-P: CIDEB Knockdown Promotes Increased Hepatic Mitochondrial Fat Oxidation and Reverses Hepatic Steatosis and Hepatic Insulin Resistance by the PKCε-Insulin Receptor Kinase Pathway
ZHENG J, NASIRI A, GASPAR R, HUBBARD B, SAKUMA I, MA X, MURRAY S, PERELIS M, BARNES W, SAMUEL V, PETERSEN K, SHULMAN G. 1577-P: CIDEB Knockdown Promotes Increased Hepatic Mitochondrial Fat Oxidation and Reverses Hepatic Steatosis and Hepatic Insulin Resistance by the PKCε-Insulin Receptor Kinase Pathway. Diabetes 2024, 73 DOI: 10.2337/db24-1577-p.Peer-Reviewed Original ResearchReceptor kinase pathwaysMitochondrial fat oxidationHepatic insulin resistanceKinase pathwayExpression of cidebAmeliorated HFD-induced hepatic steatosisHFD-induced hepatic steatosisHFD-induced insulin resistanceSteatotic liver diseasePathogenesis of type 2 diabetesHepatic steatosisCidebHyperinsulinemic-euglycemic clamp studiesHepatic triglyceride accumulationInsulin resistanceReverse hepatic steatosisTriglyceride accumulationHepatic insulin sensitivityInsulin sensitivityPathwayHepatic expressionHigh-fatWhole-body insulin sensitivityLiver diseaseTranslocation
2023
Lysophosphatidic acid triggers inflammation in the liver and white adipose tissue in rat models of 1-acyl-sn-glycerol-3-phosphate acyltransferase 2 deficiency and overnutrition
Sakuma I, Gaspar R, Luukkonen P, Kahn M, Zhang D, Zhang X, Murray S, Golla J, Vatner D, Samuel V, Petersen K, Shulman G. Lysophosphatidic acid triggers inflammation in the liver and white adipose tissue in rat models of 1-acyl-sn-glycerol-3-phosphate acyltransferase 2 deficiency and overnutrition. Proceedings Of The National Academy Of Sciences Of The United States Of America 2023, 120: e2312666120. PMID: 38127985, PMCID: PMC10756285, DOI: 10.1073/pnas.2312666120.Peer-Reviewed Original ResearchMAD2-Dependent Insulin Receptor Endocytosis Regulates Metabolic Homeostasis.
Park J, Hall C, Hubbard B, LaMoia T, Gaspar R, Nasiri A, Li F, Zhang H, Kim J, Haeusler R, Accili D, Shulman G, Yu H, Choi E. MAD2-Dependent Insulin Receptor Endocytosis Regulates Metabolic Homeostasis. Diabetes 2023, 72: 1781-1794. PMID: 37725942, PMCID: PMC10658066, DOI: 10.2337/db23-0314.Peer-Reviewed Original ResearchConceptsIR endocytosisInsulin receptor endocytosisCell division regulatorsInsulin receptorProlongs insulin actionReceptor endocytosisTranscriptomic profilesInsulin stimulationEndocytosisMetabolic homeostasisCell surfaceGenetic ablationMetabolic functionsInsulin actionP31cometMad2BubR1DisruptionSignalingRegulatorHomeostasisAdipose tissueInteractionHepatic fat accumulationMetabolismInhibition of HSD17B13 protects against liver fibrosis by inhibition of pyrimidine catabolism in nonalcoholic steatohepatitis
Luukkonen P, Sakuma I, Gaspar R, Mooring M, Nasiri A, Kahn M, Zhang X, Zhang D, Sammalkorpi H, Penttilä A, Orho-Melander M, Arola J, Juuti A, Zhang X, Yimlamai D, Yki-Järvinen H, Petersen K, Shulman G. Inhibition of HSD17B13 protects against liver fibrosis by inhibition of pyrimidine catabolism in nonalcoholic steatohepatitis. Proceedings Of The National Academy Of Sciences Of The United States Of America 2023, 120: e2217543120. PMID: 36669104, PMCID: PMC9942818, DOI: 10.1073/pnas.2217543120.Peer-Reviewed Original ResearchConceptsNonalcoholic fatty liver diseaseLiver fibrosisLiver diseaseCommon chronic liver diseaseChronic liver diseaseFatty liver diseaseRisk of fibrosisDistinct mouse modelsPyrimidine catabolismNonalcoholic steatohepatitisMouse modelTherapeutic targetFibrosisDihydropyrimidine dehydrogenaseHuman liverA variantCommon variantsMetabolomics approachDiseaseMiceInhibitionCatabolismKnockdownSteatohepatitisGimeracil
2021
An update on brown adipose tissue biology: a discussion of recent findings
Gaspar RC, Pauli JR, Shulman GI, Muñoz VR. An update on brown adipose tissue biology: a discussion of recent findings. AJP Endocrinology And Metabolism 2021, 320: e488-e495. PMID: 33459179, PMCID: PMC7988785, DOI: 10.1152/ajpendo.00310.2020.Peer-Reviewed Original ResearchConceptsBrown adipose tissueBAT thermogenesisBrown adipose tissue biologyEnergy expenditureBrown-like cellsWhole-body glucoseAdipose tissue biologyBAT metabolismAdrenergic drugsAdipose tissuePotential treatmentThermogenic activityWhite adipocytesBody glucoseFat metabolismEndocrine mechanismsBeneficial roleSecretory moleculesActivity capacityTissue biologyThermogenesisRecent findingsRecent studiesAdditional focusMetabolism
2020
A Membrane-Bound Diacylglycerol Species Induces PKCϵ-Mediated Hepatic Insulin Resistance
Lyu K, Zhang Y, Zhang D, Kahn M, Ter Horst KW, Rodrigues MRS, Gaspar RC, Hirabara SM, Luukkonen PK, Lee S, Bhanot S, Rinehart J, Blume N, Rasch MG, Serlie MJ, Bogan JS, Cline GW, Samuel VT, Shulman GI. A Membrane-Bound Diacylglycerol Species Induces PKCϵ-Mediated Hepatic Insulin Resistance. Cell Metabolism 2020, 32: 654-664.e5. PMID: 32882164, PMCID: PMC7544641, DOI: 10.1016/j.cmet.2020.08.001.Peer-Reviewed Original ResearchConceptsPlasma membraneEndoplasmic reticulumHigh-fat diet-induced hepatic insulin resistanceSubcellular fractionation methodInsulin receptor kinaseKey lipid speciesHepatic insulin resistanceDiet-induced hepatic insulin resistanceReceptor kinaseDiacylglycerol acyltransferase 2Molecular mechanismsAcute knockdownPhosphorylationLipid dropletsLipid speciesAcyltransferase 2KnockdownLiver-specific overexpressionDAG accumulationPKCϵDAG contentMembraneFractionation methodKinaseMitochondria
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