Ageing-induced decline in physical endurance in mice is associated with decrease in cardiac SUR2A and increase in cardiac susceptibility to metabolic stress: therapeutic prospects for up-regulation of SUR2A

Rajni Sudhir, Andriy Sukhodub, Qingyou Du, Sofija Jovanovic, Aleksandar Jovanovic

    Research output: Contribution to journalArticle

    16 Citations (Scopus)

    Abstract

    Ageing is characterized by decline in physical endurance which has been suggested to be partly due to diminished functional and adaptive reserve capacity of the heart. Ageing is associated with decrease in numbers of sarcolemmal ATP-sensitive K+ (K-ATP) channels, but whether this has anything to do with ageing-induced decline in physical endurance is yet to be determined. We have previously shown that the numbers of sarcolemmal K-ATP channels are controlled by the level of expression of SUR2A, a K-ATP channel regulatory subunit. Here, we have found that ageing decreases the level of SUR2A mRNA in the heart without affecting expression of pore-forming K-ATP channel subunits, Kir6.1 and Kir6.2. This effect of ageing was associated with decrease in levels of fully-assembled sarcolemmal K-ATP channels. At the same time, ageing was associated with decreased physical endurance. In order to determine whether increased expression of SUR2A would counteract ageing-induced decrease in physical endurance, we have taken advantage of mice which SUR2A levels are regulated by more efficient CMV promoter. These mice had increased resistance of cardiomyocytes to metabolic stress/hypoxia and increased physical endurance when compared to the wild type. In transgenic mice, ageing did not affect the level of SUR2A mRNA in the heart and the level of fully-assembled sarcolemmal K-ATP channels. The effect of increased SUR2A to resistance of cardiomyocytes to hypoxia and physical endurance was retained in old mice. The magnitude of these effects was such that they were significantly increased even when compared to those in wild type young mice. We conclude that (1) the level of SUR2A expression in the heart is important factor in regulating physical endurance, (2) ageing-induced decrease in cardiac SUR2A is, at least in part, responsible for ageing-induced decline in physical fitness and (3) up-regulation of SUR2A could be a viable strategy to counteract ageing-induced decline in physical endurance.

    Original languageEnglish
    Pages (from-to)147-155
    Number of pages9
    JournalBiogerontology
    Volume12
    Issue number2
    DOIs
    Publication statusPublished - Apr 2011

    Keywords

    • Ageing
    • Physical endurance
    • SUR2A
    • KATP channels
    • K-ATP CHANNELS
    • H9C2 CELLS
    • EXERCISE
    • CARDIOMYOCYTES
    • ISCHEMIA
    • GENDER
    • CARDIOPROTECTION
    • TRAFFICKING
    • EXPRESSION
    • MECHANISM

    Cite this

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    title = "Ageing-induced decline in physical endurance in mice is associated with decrease in cardiac SUR2A and increase in cardiac susceptibility to metabolic stress: therapeutic prospects for up-regulation of SUR2A",
    abstract = "Ageing is characterized by decline in physical endurance which has been suggested to be partly due to diminished functional and adaptive reserve capacity of the heart. Ageing is associated with decrease in numbers of sarcolemmal ATP-sensitive K+ (K-ATP) channels, but whether this has anything to do with ageing-induced decline in physical endurance is yet to be determined. We have previously shown that the numbers of sarcolemmal K-ATP channels are controlled by the level of expression of SUR2A, a K-ATP channel regulatory subunit. Here, we have found that ageing decreases the level of SUR2A mRNA in the heart without affecting expression of pore-forming K-ATP channel subunits, Kir6.1 and Kir6.2. This effect of ageing was associated with decrease in levels of fully-assembled sarcolemmal K-ATP channels. At the same time, ageing was associated with decreased physical endurance. In order to determine whether increased expression of SUR2A would counteract ageing-induced decrease in physical endurance, we have taken advantage of mice which SUR2A levels are regulated by more efficient CMV promoter. These mice had increased resistance of cardiomyocytes to metabolic stress/hypoxia and increased physical endurance when compared to the wild type. In transgenic mice, ageing did not affect the level of SUR2A mRNA in the heart and the level of fully-assembled sarcolemmal K-ATP channels. The effect of increased SUR2A to resistance of cardiomyocytes to hypoxia and physical endurance was retained in old mice. The magnitude of these effects was such that they were significantly increased even when compared to those in wild type young mice. We conclude that (1) the level of SUR2A expression in the heart is important factor in regulating physical endurance, (2) ageing-induced decrease in cardiac SUR2A is, at least in part, responsible for ageing-induced decline in physical fitness and (3) up-regulation of SUR2A could be a viable strategy to counteract ageing-induced decline in physical endurance.",
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    author = "Rajni Sudhir and Andriy Sukhodub and Qingyou Du and Sofija Jovanovic and Aleksandar Jovanovic",
    year = "2011",
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    Ageing-induced decline in physical endurance in mice is associated with decrease in cardiac SUR2A and increase in cardiac susceptibility to metabolic stress: therapeutic prospects for up-regulation of SUR2A. / Sudhir, Rajni; Sukhodub, Andriy; Du, Qingyou; Jovanovic, Sofija; Jovanovic, Aleksandar.

    In: Biogerontology, Vol. 12, No. 2, 04.2011, p. 147-155.

    Research output: Contribution to journalArticle

    TY - JOUR

    T1 - Ageing-induced decline in physical endurance in mice is associated with decrease in cardiac SUR2A and increase in cardiac susceptibility to metabolic stress: therapeutic prospects for up-regulation of SUR2A

    AU - Sudhir, Rajni

    AU - Sukhodub, Andriy

    AU - Du, Qingyou

    AU - Jovanovic, Sofija

    AU - Jovanovic, Aleksandar

    PY - 2011/4

    Y1 - 2011/4

    N2 - Ageing is characterized by decline in physical endurance which has been suggested to be partly due to diminished functional and adaptive reserve capacity of the heart. Ageing is associated with decrease in numbers of sarcolemmal ATP-sensitive K+ (K-ATP) channels, but whether this has anything to do with ageing-induced decline in physical endurance is yet to be determined. We have previously shown that the numbers of sarcolemmal K-ATP channels are controlled by the level of expression of SUR2A, a K-ATP channel regulatory subunit. Here, we have found that ageing decreases the level of SUR2A mRNA in the heart without affecting expression of pore-forming K-ATP channel subunits, Kir6.1 and Kir6.2. This effect of ageing was associated with decrease in levels of fully-assembled sarcolemmal K-ATP channels. At the same time, ageing was associated with decreased physical endurance. In order to determine whether increased expression of SUR2A would counteract ageing-induced decrease in physical endurance, we have taken advantage of mice which SUR2A levels are regulated by more efficient CMV promoter. These mice had increased resistance of cardiomyocytes to metabolic stress/hypoxia and increased physical endurance when compared to the wild type. In transgenic mice, ageing did not affect the level of SUR2A mRNA in the heart and the level of fully-assembled sarcolemmal K-ATP channels. The effect of increased SUR2A to resistance of cardiomyocytes to hypoxia and physical endurance was retained in old mice. The magnitude of these effects was such that they were significantly increased even when compared to those in wild type young mice. We conclude that (1) the level of SUR2A expression in the heart is important factor in regulating physical endurance, (2) ageing-induced decrease in cardiac SUR2A is, at least in part, responsible for ageing-induced decline in physical fitness and (3) up-regulation of SUR2A could be a viable strategy to counteract ageing-induced decline in physical endurance.

    AB - Ageing is characterized by decline in physical endurance which has been suggested to be partly due to diminished functional and adaptive reserve capacity of the heart. Ageing is associated with decrease in numbers of sarcolemmal ATP-sensitive K+ (K-ATP) channels, but whether this has anything to do with ageing-induced decline in physical endurance is yet to be determined. We have previously shown that the numbers of sarcolemmal K-ATP channels are controlled by the level of expression of SUR2A, a K-ATP channel regulatory subunit. Here, we have found that ageing decreases the level of SUR2A mRNA in the heart without affecting expression of pore-forming K-ATP channel subunits, Kir6.1 and Kir6.2. This effect of ageing was associated with decrease in levels of fully-assembled sarcolemmal K-ATP channels. At the same time, ageing was associated with decreased physical endurance. In order to determine whether increased expression of SUR2A would counteract ageing-induced decrease in physical endurance, we have taken advantage of mice which SUR2A levels are regulated by more efficient CMV promoter. These mice had increased resistance of cardiomyocytes to metabolic stress/hypoxia and increased physical endurance when compared to the wild type. In transgenic mice, ageing did not affect the level of SUR2A mRNA in the heart and the level of fully-assembled sarcolemmal K-ATP channels. The effect of increased SUR2A to resistance of cardiomyocytes to hypoxia and physical endurance was retained in old mice. The magnitude of these effects was such that they were significantly increased even when compared to those in wild type young mice. We conclude that (1) the level of SUR2A expression in the heart is important factor in regulating physical endurance, (2) ageing-induced decrease in cardiac SUR2A is, at least in part, responsible for ageing-induced decline in physical fitness and (3) up-regulation of SUR2A could be a viable strategy to counteract ageing-induced decline in physical endurance.

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    KW - K-ATP CHANNELS

    KW - H9C2 CELLS

    KW - EXERCISE

    KW - CARDIOMYOCYTES

    KW - ISCHEMIA

    KW - GENDER

    KW - CARDIOPROTECTION

    KW - TRAFFICKING

    KW - EXPRESSION

    KW - MECHANISM

    U2 - 10.1007/s10522-010-9306-3

    DO - 10.1007/s10522-010-9306-3

    M3 - Article

    C2 - 20972622

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    JO - Biogerontology

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    SN - 1389-5729

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