Mutations of the TMEM70 gene disrupt the biogenesis of the ATP synthase and represent the most frequent cause of autosomal recessive encephalo-cardio-myopathy with neonatal onset. Patient tissues show isolated defects in the ATP synthase, leading to the impaired mitochondrial synthesis of ATP and insufficient energy provision. In the current study, we tested the efficiency of gene complementation by using a transgenic rescue approach in spontaneously hypertensive rats with the targeted Tmem70 gene (SHR-Tmem70ko/ko), which leads to embryonic lethality. We generated SHR-Tmem70ko/ko knockout rats expressing the Tmem70 wild-type transgene (SHR-Tmem70ko/ko,tg/tg) under the control of the EF-1α universal promoter. Transgenic rescue resulted in viable animals that showed the variable expression of the Tmem70 transgene across the range of tissues and only minor differences in terms of the growth parameters. The TMEM70 protein was restored to 16-49% of the controls in the liver and heart, which was sufficient for the full biochemical complementation of ATP synthase biogenesis as well as for mitochondrial energetic function in the liver. In the heart, we observed partial biochemical complementation, especially in SHR-Tmem70ko/ko,tg/0 hemizygotes. As a result, this led to a minor impairment in left ventricle function. Overall, the transgenic rescue of Tmem70 in SHR-Tmem70ko/ko knockout rats resulted in the efficient complementation of ATP synthase deficiency and thus in the successful genetic treatment of an otherwise fatal mitochondrial disorder.

• Keywords
• ATP synthase deficiency, TMEM70 factor, gene therapy, mitochondria disease, transgenic rescue,
• Publication type
• Journal Article MeSH

Hypertension, dyslipidemia, and insulin resistance in the spontaneously hypertensive rat (SHR) can be alleviated by rescuing CD36 fatty acid translocase. The present study investigated whether transgenic rescue of CD36 in SHR could affect mitochondrial function and activity of selected metabolic enzymes in the heart. These analyses were conducted on ventricular preparations derived from SHR and from transgenic strain SHR-Cd36 that expresses a functional wild-type CD36. Our respirometric measurements revealed that mitochondria isolated from the left ventricles exhibited two times higher respiratory activity than those isolated from the right ventricles. Whereas, we did not observe any significant changes in functioning of the mitochondrial respiratory system between both rat strains, enzyme activities of total hexokinase, and both mitochondrial and total malate dehydrogenase were markedly decreased in the left ventricles of transgenic rats, compared to SHR. We also detected downregulated expression of the succinate dehydrogenase subunit SdhB (complex II) and 70 kDa peroxisomal membrane protein in the left ventricles of SHR-Cd36. These data indicate that CD36 may affect in a unique fashion metabolic substrate flexibility of the left and right ventricles.

• Keywords
• CD36, Heart, Left and right ventricles, Mitochondria, OXPHOS, SHR,
• MeSH
• ATP-Binding Cassette Transporters genetics   metabolism   MeSH
• CD36 Antigens genetics   metabolism   MeSH
• Gene Expression MeSH
• Hexokinase genetics   metabolism   MeSH
• Hypertension enzymology   genetics   physiopathology   MeSH
• Insulin Resistance MeSH
• Myocytes, Cardiac enzymology   pathology   MeSH
• Rats MeSH
• Malate Dehydrogenase genetics   metabolism   MeSH
• Mitochondria enzymology   pathology   MeSH
• Oxidative Phosphorylation MeSH
• Rats, Inbred SHR MeSH
• Rats, Transgenic MeSH
• Primary Cell Culture MeSH
• Gene Expression Regulation MeSH
• Oxygen Consumption genetics   MeSH
• Heart Ventricles enzymology   pathology   MeSH
• Succinate Dehydrogenase genetics   metabolism   MeSH
• Transgenes * MeSH
• Animals MeSH
• Check Tag
• Rats MeSH
• Male MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• ATP-Binding Cassette Transporters MeSH
• Abcd3 protein, rat MeSH Browser
• CD36 Antigens MeSH
• Hexokinase MeSH
• Malate Dehydrogenase MeSH
• Succinate Dehydrogenase MeSH

The β-adrenergic signaling pathways and antioxidant defence mechanisms play important roles in maintaining proper heart function. Here, we examined the effect of chronic normobaric hypoxia (CNH, 10% O2, 3 weeks) on myocardial β-adrenergic signaling and selected components of the antioxidant system in spontaneously hypertensive rats (SHR) and in a conplastic SHR-mtBN strain characterized by the selective replacement of the mitochondrial genome of SHR with that of the more ischemia-resistant Brown Norway strain. Our investigations revealed some intriguing differences between the two strains at the level of β-adrenergic receptors (β-ARs), activity of adenylyl cyclase (AC) and monoamine oxidase A (MAO-A), as well as distinct changes after CNH exposure. The β2-AR/β1-AR ratio was significantly higher in SHR-mtBN than in SHR, apparently due to increased expression of β2-ARs. Adaptation to hypoxia elevated β2-ARs in SHR and decreased the total number of β-ARs in SHR-mtBN. In parallel, the ability of isoprenaline to stimulate AC activity was found to be higher in SHR-mtBN than that in SHR. Interestingly, the activity of MAO-A was notably lower in SHR-mtBN than in SHR, and it was markedly elevated in both strains after exposure to hypoxia. In addition to that, CNH markedly enhanced the expression of catalase and aldehyde dehydrogenase-2 in both strains, and decreased the expression of Cu/Zn superoxide dismutase in SHR. Adaptation to CNH intensified oxidative stress to a similar extent in both strains and elevated the IL-10/TNF-α ratio in SHR-mtBN only. These data indicate that alterations in the mitochondrial genome can result in peculiar changes in myocardial β-adrenergic signaling, MAO-A activity and antioxidant defence and may, thus, affect the adaptive responses to hypoxia.

• Keywords
• Adenylyl cyclase, Antioxidant defence, Chronic hypoxia, Mitochondrial genome, Monoamine oxidase A, Myocardium, SHR, β-adrenergic receptors,
• MeSH
• Adenylyl Cyclases metabolism   MeSH
• Receptors, Adrenergic, beta metabolism   MeSH
• Hypoxia metabolism   MeSH
• Rats MeSH
• Malondialdehyde metabolism   MeSH
• Monoamine Oxidase metabolism   MeSH
• Myocardium metabolism   MeSH
• Rats, Inbred SHR MeSH
• Signal Transduction physiology   MeSH
• Animals MeSH
• Check Tag
• Rats MeSH
• Male MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Adenylyl Cyclases MeSH
• Receptors, Adrenergic, beta MeSH
• Malondialdehyde MeSH
• Monoamine Oxidase MeSH

We previously mapped hypertension-related insulin resistance quantitative trait loci (QTLs) to rat chromosomes 4, 12 and 16 using adipocytes from F2 crosses between spontaneously hypertensive (SHR) and Wistar Kyoto (WKY) rats, and subsequently identified Cd36 as the gene underlying the chromosome 4 locus. The identity of the chromosome 12 and 16 genes remains unknown. To identify whole-body phenotypes associated with the chromosome 12 and 16 linkage regions, we generated and characterised new congenic strains, with WKY donor segments introgressed onto an SHR genetic background, for the chromosome 12 and 16 linkage regions. We found a >50% increase in insulin sensitivity in both the chromosome 12 and 16 strains. Blood pressure and left ventricular mass were reduced in the two congenic strains consistent with the congenic segments harbouring SHR genes for insulin resistance, hypertension and cardiac hypertrophy. Integrated genomic analysis, using physiological and whole-genome sequence data across 42 rat strains, identified variants within the congenic regions in Upk3bl, RGD1565131 and AABR06087018.1 that were associated with blood pressure, cardiac mass and insulin sensitivity. Quantitative trait transcript analysis across 29 recombinant inbred strains showed correlation between expression of Hspb1, Zkscan5 and Pdgfrl with adipocyte volume, systolic blood pressure and cardiac mass, respectively. Comparative genome analysis showed a marked enrichment of orthologues for human GWAS-associated genes for insulin resistance within the syntenic regions of both the chromosome 12 and 16 congenic intervals. Our study defines whole-body phenotypes associated with the SHR chromosome 12 and 16 insulin-resistance QTLs, identifies candidate genes for these SHR QTLs and finds human orthologues of rat genes in these regions that associate with related human traits. Further study of these genes in the congenic strains will lead to robust identification of the underlying genes and cellular mechanisms.

• Keywords
• Congenic, Genomic, Hypertension, Insulin resistance, Rat,
• MeSH
• Genome-Wide Association Study MeSH
• Energy Metabolism genetics   MeSH
• Genomics * MeSH
• Homeostasis MeSH
• Hypertension genetics   physiopathology   MeSH
• Insulin pharmacology   MeSH
• Insulin Resistance genetics   MeSH
• Liver drug effects   metabolism   MeSH
• Polymorphism, Single Nucleotide genetics   MeSH
• Calorimetry MeSH
• Cardiomegaly genetics   physiopathology   MeSH
• Muscle, Skeletal drug effects   metabolism   MeSH
• Blood Pressure drug effects   MeSH
• Humans MeSH
• Quantitative Trait Loci genetics   MeSH
• Rats, Inbred SHR MeSH
• Gene Expression Regulation drug effects   MeSH
• Chromosomes, Mammalian genetics   MeSH
• Heart Ventricles drug effects   pathology   MeSH
• Feeding Behavior drug effects   MeSH
• Body Weight drug effects   MeSH
• Triglycerides metabolism   MeSH
• Organ Size drug effects   MeSH
• Animals MeSH
• Check Tag
• Humans MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Comparative Study MeSH
• Names of Substances
• Insulin MeSH
• Triglycerides MeSH

Dysfunction or abnormalities in the regulation of fatty acid translocase Cd36, a multifunctional membrane protein participating in uptake of long-chain fatty acids, has been linked to the development of heart diseases both in animals and humans. We have previously shown that the Cd36 transgenic spontaneously hypertensive rat (SHR-Cd36), with a wild type Cd36, has higher susceptibility to ischemic ventricular arrhythmias when compared to spontaneously hypertensive rat (SHR) carrying a mutant Cd36 gene, which may have been related to increased β-adrenergic responsiveness of these animals (Neckar et al., 2012 Physiol. Genomics 44:173-182). The present study aimed to determine whether the insertion of the wild type Cd36 into SHR would affect the function of myocardial G protein-regulated adenylyl cyclase (AC) signaling. β-Adrenergic receptors (β-ARs) were characterized by radioligand-binding experiments and the expression of selected G protein subunits, AC, and protein kinase A (PKA) was determined by RT-PCR and Western blot analyses. There was no significant difference in the amount of trimeric G proteins, but the number of β-ARs was higher (by about 35 %) in myocardial preparations from SHR-Cd36 as compared to SHR. Besides that, transgenic rats expressed increased amount (by about 20 %) of the dominant myocardial isoforms AC5/6 and contained higher levels of both nonphosphorylated (by 11 %) and phosphorylated (by 45 %) PKA. Differently stimulated AC activity in SHR-Cd36 significantly exceeded (by about 18-30 %) the enzyme activity in SHR. Changes at the molecular level were reflected by higher contractile responses to stimulation by the adrenergic agonist dobutamine. In summary, it can be concluded that the increased susceptibility to ischemic arrhythmias of SHR-Cd36 is attributable to upregulation of some components of the β-AR signaling pathway, which leads to enhanced sensitization of AC and increased cardiac adrenergic responsiveness.

• MeSH
• Adenylyl Cyclases genetics   metabolism   MeSH
• Adrenergic beta-1 Receptor Agonists pharmacology   MeSH
• CD36 Antigens genetics   metabolism   MeSH
• Receptors, Adrenergic, beta metabolism   MeSH
• Dobutamine pharmacology   MeSH
• Myocardial Contraction MeSH
• Rats MeSH
• Myocardium metabolism   MeSH
• Rats, Inbred SHR MeSH
• Rats, Transgenic MeSH
• Cyclic AMP-Dependent Protein Kinases metabolism   MeSH
• GTP-Binding Proteins metabolism   MeSH
• Signal Transduction * MeSH
• Animals MeSH
• Check Tag
• Rats MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Adenylyl Cyclases MeSH
• Adrenergic beta-1 Receptor Agonists MeSH
• CD36 Antigens MeSH
• Receptors, Adrenergic, beta MeSH
• Dobutamine MeSH
• Cyclic AMP-Dependent Protein Kinases MeSH
• GTP-Binding Proteins MeSH

The present study was undertaken to evaluate the effects of chronic treatment with c-AUCB {cis-4-[4-(3-adamantan-1-ylureido)cyclohexyl-oxy]benzoic acid}, a novel inhibitor of sEH (soluble epoxide hydrolase), which is responsible for the conversion of biologically active EETs (epoxyeicosatrienoic acids) into biologically inactive DHETEs (dihydroxyeicosatrienoic acids), on BP (blood pressure) and myocardial infarct size in male heterozygous TGR (Ren-2 renin transgenic rats) with established hypertension. Normotensive HanSD (Hannover Sprague-Dawley) rats served as controls. Myocardial ischaemia was induced by coronary artery occlusion. Systolic BP was measured in conscious animals by tail plethysmography. c-AUCB was administrated in drinking water. Renal and myocardial concentrations of EETs and DHETEs served as markers of internal production of epoxygenase metabolites. Chronic treatment with c-AUCB, which resulted in significant increases in the availability of biologically active epoxygenase metabolites in TGR (assessed as the ratio of EETs to DHETEs), was accompanied by a significant reduction in BP and a significantly reduced infarct size in TGR as compared with untreated TGR. The cardioprotective action of c-AUCB treatment was completely prevented by acute administration of a selective EETs antagonist [14,15-epoxyeicosa-5(Z)-enoic acid], supporting the notion that the improved cardiac ischaemic tolerance conferred by sEH inhibition is mediated by EETs actions at the cellular level. These findings indicate that chronic inhibition of sEH exhibits antihypertensive and cardioprotective actions in this transgenic model of angiotensin II-dependent hypertension.

• MeSH
• Angiotensin II physiology   MeSH
• Antihypertensive Agents pharmacology   MeSH
• Benzoates pharmacology   MeSH
• Epoxide Hydrolases antagonists & inhibitors   MeSH
• Hypertension drug therapy   genetics   metabolism   MeSH
• Eicosanoids metabolism   urine   MeSH
• Myocardial Infarction drug therapy   pathology   MeSH
• Cardiotonic Agents pharmacology   MeSH
• Blood Pressure MeSH
• Rats MeSH
• Urea analogs & derivatives   pharmacology   MeSH
• Rats, Sprague-Dawley MeSH
• Rats, Transgenic MeSH
• Arrhythmias, Cardiac drug therapy   MeSH
• Animals MeSH
• Check Tag
• Rats MeSH
• Male MeSH
• Female MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Research Support, N.I.H., Extramural MeSH
• Names of Substances
• 4-(4-(3-adamantan-1-ylureido)cyclohexyloxy)benzoic acid MeSH Browser
• Angiotensin II MeSH
• Antihypertensive Agents MeSH
• Benzoates MeSH
• Epoxide Hydrolases MeSH
• Eicosanoids MeSH
• Cardiotonic Agents MeSH
• Urea MeSH