Dataset Information

Comprehensive Metabolic Profiling of Age-Related Mitochondrial Dysfunction in the High-Fat-Fed ob/ob Mouse Heart

ABSTRACT: The ectopic deposition of fat is thought to lead to lipotoxicity and has been associated with mitochondrial dysfunction and diabetic cardiomyopathy. We have measured mitochondrial respiratory capacities in the hearts of ob/ob and wild-type mice on either a regular chow (RCD) or high-fat (HFD) diet across four age groups to investigate the impact of diet and age on mitochondrial function alongside a comprehensive strategy for metabolic profiling of the tissue. Myocardial mitochondrial dysfunction was only evident in ob/ob mice on RCD at 14 months, but it was detectable at 3 months on the HFD. Liquid chromatography–mass spectrometry (LC–MS) was used to study the profiles of acylcarnitines and the accumulation of triglycerides, but neither class of lipid was associated with mitochondrial dysfunction. However, a targeted LC–MS/MS analysis of markers of oxidative stress demonstrated increases in GSSG/GSH and 8-oxoguanine, in addition to the accumulation of diacylglycerols, which are lipid species linked to lipotoxicity. Our results demonstrate that myocardial mitochondria in ob/ob mice on RCD maintained a similar respiratory capacity to that of wild type until a late stage in aging. However, on a HFD, unlike wild-type mice, ob/ob mice failed to increase mitochondrial respiration, which may be associated with a complex I defect following increased oxidative damage.

INSTRUMENT(S): Quattro Premier XE (Waters), API 5500 QTRAP (AB Sciex), Xevo G2 QTOF (Waters)

SUBMITTER: Xinzhu Wang

PROVIDER: MTBLS173 | MetaboLights | 2015-11-17

REPOSITORIES: MetaboLights

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			Action	DRS
	MTBLS173	Other
	FILES	Other
	a_MTBLS173_obob_mito_paper_metabolite_profiling_mass_spectrometry-1.txt	Txt
	a_MTBLS173_obob_mito_paper_metabolite_profiling_mass_spectrometry-2.txt	Txt
	a_MTBLS173_obob_mito_paper_metabolite_profiling_mass_spectrometry.txt	Txt

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Publications

Comprehensive Metabolic Profiling of Age-Related Mitochondrial Dysfunction in the High-Fat-Fed ob/ob Mouse Heart.

Wang Xinzhu X West James A JA Murray Andrew J AJ Griffin Julian L JL

Journal of proteome research 20150622 7

The ectopic deposition of fat is thought to lead to lipotoxicity and has been associated with mitochondrial dysfunction and diabetic cardiomyopathy. We have measured mitochondrial respiratory capacities in the hearts of ob/ob and wild-type mice on either a regular chow (RCD) or high-fat (HFD) diet across four age groups to investigate the impact of diet and age on mitochondrial function alongside a comprehensive strategy for metabolic profiling of the tissue. Myocardial mitochondrial dysfunction ...[more]

PMID: 25985803

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Project description:Although mitochondrial dysfunctions are implicated in the pathogenesis of obesity, the molecular mechanisms underlying obesity-related metabolic abnormalities are still not well established. To acquire a comprehensive picture of mitochondrial molecular changes within metabolically active tissues, we focused on hepatic and muscle whole cellular transcriptome and mitochondrial proteome alterations in 16 and 48 weeks old high fat diet (HFD)-feed wild type C57BL/6J and hyperphagic, genetically modified mice with leptin dysfunction (ob/ob and db/db). On transcriptome level, the most discriminative hepatic alterations distinguished between genetically modified and wild type mice, and between overnight fasted and non-fasted mice, while the muscle transcriptional alterations related mainly to the fasting state. The fractions of uniquely different proteins were consistently higher in hyperphagic than in HFD-fed mice and in fasted than non-fasted mice . The liver samples revealed overall higher number of differentially expressed RNAs and proteins than muscle samples. Differentially expressed genes and proteins in the liver, but not in the muscle, could be assigned to several Gene Ontology terms, including oxidation-reduction and several metabolic processes. Thus, altered expression of genes and proteins accompanied the state of obesity and was quantitatively different in the liver and muscle. Our parallel microarray- and quantitative mitochondrial mass spectrometry-based study performed on hepatic and muscle samples identified a higher number of differentially expressed proteins than any other studies investigating obesity-related proteomes. However, even with our integrated transcriptomic and proteomic approach still many details and dynamics of a chain of metabolic events leading to obesity-related mitochondrial dysfunctions remain unresolved . 48 samples each of liver and muscle (total samples: 96). Samples splitted equally according to 3 criterions: age (24 young/24 old), fasting status (24 fasted/24 non fasted), and strain+diet (12 each: B6.V-Lep ob/J+D12450B, B6.BKS(D)-Lep rdb/J+D12450B, C57BL/6J+D12450B, C57BL/6J+D12492). Overall 3 replicates for each strain+diet/age/fasting_status combination. Low fat diet = D12450B; high fat diet = D12492.

Project description:Caloric Restriction in Leptin Deficiency Worsens Myocardial Steatosis: Failure to Upregulate PPAR gamma and Thermogenic Glyecrolipid/Fatty Acid Cycling Growing evidence supports an anti-lipotoxic role for leptin in preventing inappropriate peripheral tissue lipid deposition. Obese, leptin deficient ob/ob mice develop left ventricular (LV) hypertrophy and myocardial steatosis with increased apoptosis and decreased longevity. Here we investigated the cardiac effects of caloric restriction in leptin deficiency. Echocardiography was performed on C57Bl/6 wild-type mice (WT) and 7-month-old ob/ob mice fed ad lib, leptin-repleted (LR-ob/ob), or calorie-restricted (CR-ob/ob) for four weeks. Ventricular tissue was examined by electron microscopy (EM), mitochondrial coupling assay, and microarray expression profiling. LR and CR-ob/ob mice showed decreased body weight, heart weight, and LV wall thickness compared to ad lib ob/ob mice. LV fractional shortening was decreased in ad lib ob/ob mice, but restored to WT levels in LR and CR groups. However, EM revealed severe cardiac steatosis in the CR-ob/ob group compared to only moderate steatosis in ad lib ob/ob . Despite marked cardiac steatosis, CR (like LR) restored mitochondrial coupling to WT levels. CR up-regulated genes associated with oxidative stress and cell death, changes suggestive of cardiac lipotoxicity. LR, but not CR was shown to induce core genes involved in glycerolipid/free fatty acid cycling, a highly thermogenic pathway that can reduce intracellular lipid stores. LR, but not CR up-regulated and restored PGC1 and PPARto wild type levels; CR paradoxically further suppressed cardiac PPAR. Thus, leptin is essential in protecting the heart from lipotoxicity, and the inability to up-regulate the thermogenic glycerolipid/free fatty acid cycling pathway may impair the response of leptin deficient animals to the lipotoxic stress of calorie restriction. 6 month aged ob/ob mice were either leptin repleted with osmotic mini-pumps, calorie restricted to match the caloric intake of the leptin repleted mice, or fed ad lib for one month. 6-8 month C57Bl/6J mice were aged to serve as controls.