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Al-Horani RA, Janaydeh S, Al-Trad B, Aljanabi MM, Muhaidat R. Acute Exercise Promptly Normalizes Myocardial Myosin Heavy-Chain Isoform mRNA Composition in Diabetic Rats: Implications for Diabetic Cardiomyopathy. MEDICINA (KAUNAS, LITHUANIA) 2023; 59:2193. [PMID: 38138296 PMCID: PMC10744754 DOI: 10.3390/medicina59122193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2023] [Revised: 12/05/2023] [Accepted: 12/14/2023] [Indexed: 12/24/2023]
Abstract
Background and Objectives: The acute effects of exercise on the myosin heavy-chain (MHC) isoform mRNA expression and the upstream transcription factors in diabetic and non-diabetic hearts remain unexplored. We aimed to determine the acute effect of a single exercise session on the expression of left ventricular MHC, MHC-α and MHC-β, and thyroid receptor (TR), TR-α1 and TR-β, isoform mRNA in diabetic and non-diabetic rats. Materials and Methods: Sprague-Dawley rats were assigned to four groups: non-diabetic control (CS), diabetic exercise (DIEX), sedentary diabetic (DIS), and non-diabetic exercise (CEX). Diabetes was induced via streptozotocin injection (55 mg/kg). DIEX and CEX rats performed an exercise session (60 min at 50 m/min and 0% grade) 6-7 weeks after diabetes induction. Results: MHC-α mRNA was lower in DIS (p = 0.03) and not different in DIEX (p = 0.1) relative to CS. DIS showed higher MHC-β mRNA than the non-diabetic rats, CS and CEX (p = 0.02 and p = 0.009, respectively). MHC-β mRNA in DIEX was normalized to non-diabetic levels in CS (p = 0.3). TR-α1 was higher in DIS and not different in DIEX relative to CS and CEX (p = 0.03 and p = 1.0, respectively). In CEX, exercise did not change MHC-α, MHC-β, and TR-α1 relative to CS (p = 1.0). TR-β was not different between groups. Conclusion: In conclusion, exercise appears to acutely normalize the myocardial MHC and TR isoform mRNA expression only in the diabetic heart. These responses may induce therapeutic mechanisms other than changing the MHC isoform composition.
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Affiliation(s)
| | - Saja Janaydeh
- Department of Biological Sciences, Yarmouk University, Irbid 21163, Jordan; (S.J.); (B.A.-T.); (R.M.)
| | - Bahaa Al-Trad
- Department of Biological Sciences, Yarmouk University, Irbid 21163, Jordan; (S.J.); (B.A.-T.); (R.M.)
| | - Mukhallad Mohammed Aljanabi
- Department of Physiology, Faculty of Medicine, Jordan University of Science and Technology, Irbid 22110, Jordan;
| | - Riyadh Muhaidat
- Department of Biological Sciences, Yarmouk University, Irbid 21163, Jordan; (S.J.); (B.A.-T.); (R.M.)
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Vásquez-Trincado C, Patel M, Sivaramakrishnan A, Bekeová C, Anderson-Pullinger L, Wang N, Tang HY, Seifert EL. Adaptation of the heart to Frataxin depletion: Evidence that integrated stress response can predominate over mTORC1 activation. Hum Mol Genet 2021; 33:ddab216. [PMID: 34550363 PMCID: PMC11000666 DOI: 10.1093/hmg/ddab216] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 07/07/2021] [Accepted: 07/08/2021] [Indexed: 11/12/2022] Open
Abstract
Friedreich's ataxia (FRDA) is an inherited disorder caused by depletion of frataxin (FXN), a mitochondrial protein required for iron-sulfur cluster (ISC) biogenesis. Cardiac dysfunction is the main cause of death. Yet pathogenesis, and, more generally, how the heart adapts to FXN loss, remain poorly understood, though are expected to be linked to an energy deficit. We modified a transgenic (TG) mouse model of inducible FXN depletion that permits phenotypic evaluation of the heart at different FXN levels, and focused on substrate-specific bioenergetics and stress signaling. When FXN protein in the TG heart was 17% of normal, bioenergetics and signaling were not different from control. When, 8 weeks later, FXN was ~ 97% depleted in the heart, TG heart mass and cardiomyocyte cross-sectional area were less, without evidence of fibrosis or apoptosis. mTORC1 signaling was activated, as was the integrated stress response, evidenced by greater phosphorylation of eIF2α relative to total eIF2α, and decreased protein translation. We interpret these results to suggest that, in TG hearts, an anabolic stimulus was constrained by eIF2α phosphorylation. Cardiac contractility was maintained in the 97%-FXN-depleted hearts, possibly contributed by an unexpected preservation of β-oxidation, though pyruvate oxidation was lower. Bioenergetics alterations were matched by changes in the mitochondrial proteome, including a non-uniform decrease in abundance of ISC-containing proteins. Altogether, these findings suggest that the FXN depleted heart can suppress a major ATP demanding process such as protein translation, which, together with some preservation of β-oxidation, could be adaptive, at least in the short term.
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Affiliation(s)
- César Vásquez-Trincado
- MitoCare Center for Mitochondrial Imaging Research and Diagnostics, Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA 19107, United States
| | - Monika Patel
- MitoCare Center for Mitochondrial Imaging Research and Diagnostics, Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA 19107, United States
| | - Aishwarya Sivaramakrishnan
- MitoCare Center for Mitochondrial Imaging Research and Diagnostics, Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA 19107, United States
| | - Carmen Bekeová
- MitoCare Center for Mitochondrial Imaging Research and Diagnostics, Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA 19107, United States
| | - Lauren Anderson-Pullinger
- MitoCare Center for Mitochondrial Imaging Research and Diagnostics, Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA 19107, United States
| | - Nadan Wang
- Center for Translational Medicine, Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA 19107, United States
| | - Hsin-Yao Tang
- Proteomics and Metabolomics Facility, The Wistar Institute, Philadelphia, PA 19104, United States
| | - Erin L Seifert
- MitoCare Center for Mitochondrial Imaging Research and Diagnostics, Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA 19107, United States
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