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 Research
2021
Short-term overnutrition induces white adipose tissue insulin resistance through sn-1,2-diacylglycerol – PKCε – insulin receptorT1160 phosphorylation
Lyu K, Zhang D, Song J, Li X, Perry RJ, Samuel VT, Shulman GI. Short-term overnutrition induces white adipose tissue insulin resistance through sn-1,2-diacylglycerol – PKCε – insulin receptorT1160 phosphorylation. JCI Insight 2021, 6: e139946. PMID: 33411692, PMCID: PMC7934919, DOI: 10.1172/jci.insight.139946.Peer-Reviewed Original ResearchConceptsInsulin resistanceInsulin actionAdipose tissue insulin resistanceTissue insulin resistanceWT control miceHyperinsulinemic-euglycemic clampShort-term HFDTissue insulin actionAdipose tissue insulin actionDiet-fed ratsPotential therapeutic targetHFD feedingControl miceInsulin sensitivityTherapeutic targetLipolysis suppressionImpairs insulinHFDPKCε activationGlucose uptakeΕ activationMiceDiacylglycerol accumulationRecent evidenceProtein kinase C
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 methodKinaseMitochondriaMetabolic control analysis of hepatic glycogen synthesis in vivo
Nozaki Y, Petersen MC, Zhang D, Vatner DF, Perry RJ, Abulizi A, Haedersdal S, Zhang XM, Butrico GM, Samuel VT, Mason GF, Cline GW, Petersen KF, Rothman DL, Shulman GI. Metabolic control analysis of hepatic glycogen synthesis in vivo. Proceedings Of The National Academy Of Sciences Of The United States Of America 2020, 117: 8166-8176. PMID: 32188779, PMCID: PMC7149488, DOI: 10.1073/pnas.1921694117.Peer-Reviewed Original Research
2019
Distinct Hepatic PKA and CDK Signaling Pathways Control Activity-Independent Pyruvate Kinase Phosphorylation and Hepatic Glucose Production
Gassaway BM, Cardone RL, Padyana AK, Petersen MC, Judd ET, Hayes S, Tong S, Barber KW, Apostolidi M, Abulizi A, Sheetz JB, Kshitiz, Aerni HR, Gross S, Kung C, Samuel VT, Shulman GI, Kibbey RG, Rinehart J. Distinct Hepatic PKA and CDK Signaling Pathways Control Activity-Independent Pyruvate Kinase Phosphorylation and Hepatic Glucose Production. Cell Reports 2019, 29: 3394-3404.e9. PMID: 31825824, PMCID: PMC6951436, DOI: 10.1016/j.celrep.2019.11.009.Peer-Reviewed Original ResearchConceptsCyclin-dependent kinasesMetabolic control pointPhosphorylation sitesNuclear retentionCDK activityPKL activityDays high-fat dietKinase phosphorylationImportant enzymePyruvate kinaseHigh-fat dietS113KinaseEnzyme kineticsPhosphorylationAdditional control pointsRegulationGlucose productionHepatic glucose productionInsulin resistanceGlycolysisEnzymePKAPathwayActivity
2018
PEPCK1 Antisense Oligonucleotide Prevents Adiposity and Impairs Hepatic Glycogen Synthesis in High-Fat Male Fed Rats
Beddow SA, Gattu AK, Vatner DF, Paolella L, Alqarzaee A, Tashkandi N, Popov V, Church C, Rodeheffer M, Cline G, Geisler J, Bhanot S, Samuel VT. PEPCK1 Antisense Oligonucleotide Prevents Adiposity and Impairs Hepatic Glycogen Synthesis in High-Fat Male Fed Rats. Endocrinology 2018, 160: 205-219. PMID: 30445425, PMCID: PMC6307100, DOI: 10.1210/en.2018-00630.Peer-Reviewed Original ResearchMeSH KeywordsAdipose Tissue, WhiteAdiposityAnimalsDiabetes Mellitus, Type 2Diet, High-FatGlucokinaseHumansInsulinIntracellular Signaling Peptides and ProteinsLipogenesisLiverLiver GlycogenMaleMiceMice, Inbred C57BLOligonucleotides, AntisensePhosphoenolpyruvate Carboxykinase (GTP)RatsRats, Sprague-DawleyConceptsHepatic glycogen synthesisAdipose tissueAntisense oligonucleotideType 2 diabetes mellitusWhite adipose tissue massIncreased hepatic gluconeogenesisChow fed ratsHepatic insulin sensitivityMale Sprague-DawleyAdipose tissue massHepatic insulin resistanceWhite adipose tissueHepatic glucose productionDe novo lipogenesisHepatic glucokinase expressionControl antisense oligonucleotideGlycogen synthesisTranscription factor 3HFF ratsDiabetes mellitusHepatic steatosisInsulin resistanceHyperglycemic clampPlasma glucoseInsulin sensitivityPKCε contributes to lipid-induced insulin resistance through cross talk with p70S6K and through previously unknown regulators of insulin signaling
Gassaway BM, Petersen MC, Surovtseva YV, Barber KW, Sheetz JB, Aerni HR, Merkel JS, Samuel VT, Shulman GI, Rinehart J. PKCε contributes to lipid-induced insulin resistance through cross talk with p70S6K and through previously unknown regulators of insulin signaling. Proceedings Of The National Academy Of Sciences Of The United States Of America 2018, 115: e8996-e9005. PMID: 30181290, PMCID: PMC6156646, DOI: 10.1073/pnas.1804379115.Peer-Reviewed Original ResearchMeSH KeywordsAnimalsAnimals, Genetically ModifiedDiabetes Mellitus, Type 2Diet, High-FatDisease Models, AnimalGene Knockdown TechniquesHumansInsulinInsulin Receptor Substrate ProteinsInsulin ResistanceLipid MetabolismLiverPhosphorylationProtein Kinase C-epsilonProteomicsRatsReceptor, InsulinRibosomal Protein S6Ribosomal Protein S6 Kinases, 70-kDaRNA, Small InterferingSignal TransductionConceptsHigh-fat diet-induced hepatic insulin resistanceDiet-induced hepatic insulin resistanceLipid-induced insulin resistanceProtein phosphorylationSiRNA-based screenProtein kinase C εSet of proteinsCross talkHepatic insulin resistanceQuantitative phosphoproteomicsMotif analysisUnknown regulatorKinase assaysPhosphoproteomic dataCanonical insulinP70S6KInsulin receptorImpact of lipidSystem-level approachPKCεDiacylglycerolPhosphorylationKey mediatorNew therapeutic approachesInsulin resistanceAngptl8 antisense oligonucleotide improves adipose lipid metabolism and prevents diet-induced NAFLD and hepatic insulin resistance in rodents
Vatner DF, Goedeke L, Camporez JG, Lyu K, Nasiri AR, Zhang D, Bhanot S, Murray SF, Still CD, Gerhard GS, Shulman GI, Samuel VT. Angptl8 antisense oligonucleotide improves adipose lipid metabolism and prevents diet-induced NAFLD and hepatic insulin resistance in rodents. Diabetologia 2018, 61: 1435-1446. PMID: 29497783, PMCID: PMC5940564, DOI: 10.1007/s00125-018-4579-1.Peer-Reviewed Original ResearchMeSH KeywordsAdipose TissueAngiopoietin-Like Protein 8Angiopoietin-like ProteinsAnimalsBody CompositionCalorimetry, IndirectDiet, High-FatGlucose Tolerance TestInsulin ResistanceLipid MetabolismMaleMiceMice, Inbred C57BLNon-alcoholic Fatty Liver DiseaseOligonucleotides, AntisensePeptide HormonesRatsRats, Sprague-DawleyConceptsHepatic insulin resistanceAdipose tissue lipoprotein lipaseInsulin resistanceEctopic lipid accumulationTissue lipoprotein lipaseAdipose tissueLipid uptakeTolerance testFed miceNon-alcoholic fatty liver diseaseAntisense oligonucleotideMixed meal tolerance testLipoprotein lipaseLipid accumulationDiet-induced NAFLDBariatric surgery patientsFatty liver diseaseHyperinsulinaemic euglycaemic clampMeal tolerance testSecond-generation antisense oligonucleotideAmeliorate insulin resistanceType 2 diabetesLipid-induced hepatic insulin resistanceLipoprotein lipase inhibitorWhite adipose tissue
2015
Insulin-independent regulation of hepatic triglyceride synthesis by fatty acids
Vatner DF, Majumdar SK, Kumashiro N, Petersen MC, Rahimi Y, Gattu AK, Bears M, Camporez JP, Cline GW, Jurczak MJ, Samuel VT, Shulman GI. Insulin-independent regulation of hepatic triglyceride synthesis by fatty acids. Proceedings Of The National Academy Of Sciences Of The United States Of America 2015, 112: 1143-1148. PMID: 25564660, PMCID: PMC4313795, DOI: 10.1073/pnas.1423952112.Peer-Reviewed Original Research
2013
Targeting Pyruvate Carboxylase Reduces Gluconeogenesis and Adiposity and Improves Insulin Resistance
Kumashiro N, Beddow SA, Vatner DF, Majumdar SK, Cantley JL, Guebre-Egziabher F, Fat I, Guigni B, Jurczak MJ, Birkenfeld AL, Kahn M, Perler BK, Puchowicz MA, Manchem VP, Bhanot S, Still CD, Gerhard GS, Petersen KF, Cline GW, Shulman GI, Samuel VT. Targeting Pyruvate Carboxylase Reduces Gluconeogenesis and Adiposity and Improves Insulin Resistance. Diabetes 2013, 62: 2183-2194. PMID: 23423574, PMCID: PMC3712050, DOI: 10.2337/db12-1311.Peer-Reviewed Original ResearchConceptsPyruvate carboxylaseAntisense oligonucleotideHepatocyte fatty acid oxidationInsulin resistanceNonalcoholic fatty liver diseaseZucker diabetic fatty ratsHigh fat-fed ratsFatty liver diseaseLiver biopsy specimensDiabetic fatty ratsPlasma lipid concentrationsType 2 diabetesHepatic insulin sensitivityHuman liver biopsy specimensEndogenous glucose productionHepatic insulin resistancePlasma glucose concentrationPotential therapeutic approachSpecific antisense oligonucleotideFat-fed ratsCarboxylaseFatty acid oxidationDe novo fatty acid synthesisLiver diseaseTissue-specific inhibitionThyroid hormone receptor-β agonists prevent hepatic steatosis in fat-fed rats but impair insulin sensitivity via discrete pathways
Vatner DF, Weismann D, Beddow SA, Kumashiro N, Erion DM, Liao XH, Grover GJ, Webb P, Phillips KJ, Weiss RE, Bogan JS, Baxter J, Shulman GI, Samuel VT. Thyroid hormone receptor-β agonists prevent hepatic steatosis in fat-fed rats but impair insulin sensitivity via discrete pathways. AJP Endocrinology And Metabolism 2013, 305: e89-e100. PMID: 23651850, PMCID: PMC3725564, DOI: 10.1152/ajpendo.00573.2012.Peer-Reviewed Original ResearchMeSH KeywordsAcetatesAnilidesAnimalsDietary FatsFatty LiverGene ExpressionGluconeogenesisGlucose Transporter Type 4HyperglycemiaHyperinsulinismInsulin ResistanceMaleMuscle, SkeletalNon-alcoholic Fatty Liver DiseasePhenolsRatsRats, Sprague-DawleySignal TransductionThyroid Hormone Receptors betaTriglyceridesConceptsEndogenous glucose productionHepatic insulin sensitivityInsulin sensitivityHepatic steatosisFat-fed ratsInsulin-stimulated peripheral glucose disposalTRβ agonistsInsulin-stimulated skeletal muscle glucose uptakePotent lipid-lowering drugsNonalcoholic fatty liver diseaseWhite adipose tissue lipolysisMale Sprague-Dawley ratsSkeletal muscle glucose uptakeGC-1 treatmentPeripheral glucose disposalFatty liver diseaseImpairs insulin sensitivityLipid-lowering drugsHepatic triglyceride contentAdipose tissue lipolysisMuscle glucose uptakeSprague-Dawley ratsHepatic insulin resistanceSkeletal muscle insulinPotential adverse effects
2009
Fasting hyperglycemia is not associated with increased expression of PEPCK or G6Pc in patients with Type 2 Diabetes
Samuel VT, Beddow SA, Iwasaki T, Zhang XM, Chu X, Still CD, Gerhard GS, Shulman GI. Fasting hyperglycemia is not associated with increased expression of PEPCK or G6Pc in patients with Type 2 Diabetes. Proceedings Of The National Academy Of Sciences Of The United States Of America 2009, 106: 12121-12126. PMID: 19587243, PMCID: PMC2707270, DOI: 10.1073/pnas.0812547106.Peer-Reviewed Original ResearchMeSH KeywordsAdultAnimalsDiabetes Mellitus, Type 2Dietary FatsFastingFeeding BehaviorFemaleGene Expression Regulation, EnzymologicGluconeogenesisGlucose-6-PhosphataseHumansHyperglycemiaHyperinsulinismInsulin Infusion SystemsLiverMaleMiddle AgedPhosphoenolpyruvate Carboxykinase (ATP)RatsRats, Sprague-DawleyStreptozocinConceptsHigh-fat feedingEndogenous glucose productionHFF ratsExpression of PEPCKHepatic expressionType 2 diabetes mellitusBeta-cell compensationBeta-cell responseFirst rat modelPortal vein infusionLiver biopsy samplesHigher plasma glucosePhosphoenolpyruvate carboxykinaseBariatric surgeryT2DM patientsDiabetes mellitusInsulin resistancePlasma insulinPlasma glucosePortal infusionRat modelRodent modelsVein infusionHyperglycemiaKey gluconeogenic enzymes
2007
Inhibition of protein kinase Cε prevents hepatic insulin resistance in nonalcoholic fatty liver disease
Samuel VT, Liu ZX, Wang A, Beddow SA, Geisler JG, Kahn M, Zhang XM, Monia BP, Bhanot S, Shulman GI. Inhibition of protein kinase Cε prevents hepatic insulin resistance in nonalcoholic fatty liver disease. Journal Of Clinical Investigation 2007, 117: 739-745. PMID: 17318260, PMCID: PMC1797607, DOI: 10.1172/jci30400.Peer-Reviewed Original ResearchConceptsHepatic insulin resistanceNonalcoholic fatty liver diseaseFatty liver diseaseInsulin resistanceHigh-fat feedingLiver diseaseFat-induced hepatic insulin resistanceType 2 diabetes mellitusType 2 diabetesHepatic fat accumulationNovel therapeutic targetInsulin receptor kinase activityDiabetes mellitusHepatic steatosisFat accumulationRats resultsTherapeutic targetHepatic insulinReceptor kinase activityProtein kinase CεInsulin receptorCausal roleIsoforms of PKCAntisense oligonucleotideRats
2004
Mechanism of Hepatic Insulin Resistance in Non-alcoholic Fatty Liver Disease*
Samuel VT, Liu ZX, Qu X, Elder BD, Bilz S, Befroy D, Romanelli AJ, Shulman GI. Mechanism of Hepatic Insulin Resistance in Non-alcoholic Fatty Liver Disease*. Journal Of Biological Chemistry 2004, 279: 32345-32353. PMID: 15166226, DOI: 10.1074/jbc.m313478200.Peer-Reviewed Original ResearchMeSH KeywordsAnimalsBlotting, WesternCell MembraneCytosolDeoxyglucoseEnzyme ActivationFatty AcidsFatty LiverGlycogenGlycogen SynthaseInsulinInsulin ResistanceLipid MetabolismLiverMaleMitogen-Activated Protein Kinase 8Mitogen-Activated Protein KinasesPhosphorylationPrecipitin TestsProtein IsoformsProtein Kinase CProtein Kinase C-epsilonProtein TransportRatsRats, Sprague-DawleyRNA, MessengerSignal TransductionTime FactorsTyrosineConceptsHepatic insulin resistanceNon-alcoholic fatty liver diseaseEndogenous glucose productionFatty liver diseaseInsulin resistanceHepatic fat accumulationFat feedingLiver diseaseFat accumulationFF groupInsulin-stimulated peripheral glucose disposalShort-term fat feedingSkeletal muscle fat contentBasal endogenous glucose productionShort-term high-fat feedingPeripheral glucose disposalHigh-fat feedingIRS-1PKC-epsilonAbility of insulinAcyl-CoA contentInsulin-stimulated IRS-1IRS-2 tyrosine phosphorylationLiver triglyceridesFatty liver