Defining the role of DAG, mitochondrial function, and lipid deposition in palmitate-induced proinflammatory signaling and its counter-modulation by palmitoleate

Katherine Macrae, Clare Stretton, Christopher Lipina, Agnieszka Blachnio-Zabielska, Marcin Baranowski, Jan Gorski, Anna Marley, Harinder S Hundal

    Research output: Contribution to journalArticle

    26 Citations (Scopus)

    Abstract

    Chronic exposure of skeletal muscle to saturated fatty acids, such as palmitate (C16:0), enhances proinflammatory IKK-NF?B signaling by a mechanism involving the MAP kinase (Raf-MEK-ERK) pathway. Raf activation can be induced by its dissociation from the Raf-kinase inhibitor protein (RKIP) by diacylglycerol (DAG)-sensitive protein kinase C (PKC). However, whether these molecules mediate the proinflammatory action of palmitate, an important precursor for DAG synthesis, is currently unknown. Here, involvement of DAG-sensitive PKCs, RKIP, and the structurally related monounsaturated fatty acid palmitoleate (C16:1) on proinflammatory signaling are investigated. Palmitate, but not palmitoleate, induced phosphorylation/activation of the MEK-ERK-IKK axis and proinflammatory cytokine (IL-6, CINC-1) expression. Palmitate increased intramyocellular DAG and invoked PKC-dependent RKIP(Ser153) phosphorylation, resulting in RKIP-Raf1 dissociation and MEK-ERK signaling. These responses were mimicked by PMA, a DAG mimetic and PKC activator. However, while pharmacological inhibition of PKC suppressed PMA-induced activation of MEK-ERK-IKK signaling, activation by palmitate was upheld, suggesting that DAG-sensitive PKC and RKIP were dispensable for palmitate's proinflammatory action. Strikingly, the proinflammatory effect of palmitate was potently repressed by palmitoleate. This repression was not due to reduced palmitate uptake but linked to increased neutral lipid storage and enhanced cellular oxidative capacity brought about by palmitoleate's ability to restrain palmitate-induced mitochondrial dysfunction.
    Original languageEnglish
    Pages (from-to)2366-2378
    Number of pages13
    JournalJournal of Lipid Research
    Volume54
    Issue number9
    DOIs
    Publication statusPublished - Sep 2013

    Fingerprint

    Palmitates
    Diglycerides
    Phosphatidylethanolamine Binding Protein
    Modulation
    Lipids
    Mitogen-Activated Protein Kinase Kinases
    Protein Kinase C
    Chemical activation
    Phosphorylation
    raf Kinases
    Diacylglycerol Kinase
    palmitoleic acid
    Monounsaturated Fatty Acids
    MAP Kinase Signaling System
    Muscle
    Interleukin-6
    Skeletal Muscle
    Fatty Acids
    Pharmacology
    Cytokines

    Cite this

    Macrae, Katherine ; Stretton, Clare ; Lipina, Christopher ; Blachnio-Zabielska, Agnieszka ; Baranowski, Marcin ; Gorski, Jan ; Marley, Anna ; Hundal, Harinder S. / Defining the role of DAG, mitochondrial function, and lipid deposition in palmitate-induced proinflammatory signaling and its counter-modulation by palmitoleate. In: Journal of Lipid Research. 2013 ; Vol. 54, No. 9. pp. 2366-2378.
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    abstract = "Chronic exposure of skeletal muscle to saturated fatty acids, such as palmitate (C16:0), enhances proinflammatory IKK-NF?B signaling by a mechanism involving the MAP kinase (Raf-MEK-ERK) pathway. Raf activation can be induced by its dissociation from the Raf-kinase inhibitor protein (RKIP) by diacylglycerol (DAG)-sensitive protein kinase C (PKC). However, whether these molecules mediate the proinflammatory action of palmitate, an important precursor for DAG synthesis, is currently unknown. Here, involvement of DAG-sensitive PKCs, RKIP, and the structurally related monounsaturated fatty acid palmitoleate (C16:1) on proinflammatory signaling are investigated. Palmitate, but not palmitoleate, induced phosphorylation/activation of the MEK-ERK-IKK axis and proinflammatory cytokine (IL-6, CINC-1) expression. Palmitate increased intramyocellular DAG and invoked PKC-dependent RKIP(Ser153) phosphorylation, resulting in RKIP-Raf1 dissociation and MEK-ERK signaling. These responses were mimicked by PMA, a DAG mimetic and PKC activator. However, while pharmacological inhibition of PKC suppressed PMA-induced activation of MEK-ERK-IKK signaling, activation by palmitate was upheld, suggesting that DAG-sensitive PKC and RKIP were dispensable for palmitate's proinflammatory action. Strikingly, the proinflammatory effect of palmitate was potently repressed by palmitoleate. This repression was not due to reduced palmitate uptake but linked to increased neutral lipid storage and enhanced cellular oxidative capacity brought about by palmitoleate's ability to restrain palmitate-induced mitochondrial dysfunction.",
    author = "Katherine Macrae and Clare Stretton and Christopher Lipina and Agnieszka Blachnio-Zabielska and Marcin Baranowski and Jan Gorski and Anna Marley and Hundal, {Harinder S}",
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    Defining the role of DAG, mitochondrial function, and lipid deposition in palmitate-induced proinflammatory signaling and its counter-modulation by palmitoleate. / Macrae, Katherine; Stretton, Clare; Lipina, Christopher; Blachnio-Zabielska, Agnieszka; Baranowski, Marcin; Gorski, Jan; Marley, Anna; Hundal, Harinder S.

    In: Journal of Lipid Research, Vol. 54, No. 9, 09.2013, p. 2366-2378.

    Research output: Contribution to journalArticle

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    T1 - Defining the role of DAG, mitochondrial function, and lipid deposition in palmitate-induced proinflammatory signaling and its counter-modulation by palmitoleate

    AU - Macrae, Katherine

    AU - Stretton, Clare

    AU - Lipina, Christopher

    AU - Blachnio-Zabielska, Agnieszka

    AU - Baranowski, Marcin

    AU - Gorski, Jan

    AU - Marley, Anna

    AU - Hundal, Harinder S

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    N2 - Chronic exposure of skeletal muscle to saturated fatty acids, such as palmitate (C16:0), enhances proinflammatory IKK-NF?B signaling by a mechanism involving the MAP kinase (Raf-MEK-ERK) pathway. Raf activation can be induced by its dissociation from the Raf-kinase inhibitor protein (RKIP) by diacylglycerol (DAG)-sensitive protein kinase C (PKC). However, whether these molecules mediate the proinflammatory action of palmitate, an important precursor for DAG synthesis, is currently unknown. Here, involvement of DAG-sensitive PKCs, RKIP, and the structurally related monounsaturated fatty acid palmitoleate (C16:1) on proinflammatory signaling are investigated. Palmitate, but not palmitoleate, induced phosphorylation/activation of the MEK-ERK-IKK axis and proinflammatory cytokine (IL-6, CINC-1) expression. Palmitate increased intramyocellular DAG and invoked PKC-dependent RKIP(Ser153) phosphorylation, resulting in RKIP-Raf1 dissociation and MEK-ERK signaling. These responses were mimicked by PMA, a DAG mimetic and PKC activator. However, while pharmacological inhibition of PKC suppressed PMA-induced activation of MEK-ERK-IKK signaling, activation by palmitate was upheld, suggesting that DAG-sensitive PKC and RKIP were dispensable for palmitate's proinflammatory action. Strikingly, the proinflammatory effect of palmitate was potently repressed by palmitoleate. This repression was not due to reduced palmitate uptake but linked to increased neutral lipid storage and enhanced cellular oxidative capacity brought about by palmitoleate's ability to restrain palmitate-induced mitochondrial dysfunction.

    AB - Chronic exposure of skeletal muscle to saturated fatty acids, such as palmitate (C16:0), enhances proinflammatory IKK-NF?B signaling by a mechanism involving the MAP kinase (Raf-MEK-ERK) pathway. Raf activation can be induced by its dissociation from the Raf-kinase inhibitor protein (RKIP) by diacylglycerol (DAG)-sensitive protein kinase C (PKC). However, whether these molecules mediate the proinflammatory action of palmitate, an important precursor for DAG synthesis, is currently unknown. Here, involvement of DAG-sensitive PKCs, RKIP, and the structurally related monounsaturated fatty acid palmitoleate (C16:1) on proinflammatory signaling are investigated. Palmitate, but not palmitoleate, induced phosphorylation/activation of the MEK-ERK-IKK axis and proinflammatory cytokine (IL-6, CINC-1) expression. Palmitate increased intramyocellular DAG and invoked PKC-dependent RKIP(Ser153) phosphorylation, resulting in RKIP-Raf1 dissociation and MEK-ERK signaling. These responses were mimicked by PMA, a DAG mimetic and PKC activator. However, while pharmacological inhibition of PKC suppressed PMA-induced activation of MEK-ERK-IKK signaling, activation by palmitate was upheld, suggesting that DAG-sensitive PKC and RKIP were dispensable for palmitate's proinflammatory action. Strikingly, the proinflammatory effect of palmitate was potently repressed by palmitoleate. This repression was not due to reduced palmitate uptake but linked to increased neutral lipid storage and enhanced cellular oxidative capacity brought about by palmitoleate's ability to restrain palmitate-induced mitochondrial dysfunction.

    U2 - 10.1194/jlr.M036996

    DO - 10.1194/jlr.M036996

    M3 - Article

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