Distinct NF-kappa B regulation by shear stress through ras-dependent I kappa B alpha oscillations - Real-time analysis of flow-mediated activation in live cells

R. Ganguli, L. Persson, I. Palmer, R. Smallwood, R.A. Black, E. Qwarnstrom

    Research output: Contribution to journalArticle

    28 Citations (Scopus)

    Abstract

    NF-{kappa}B, a transcription factor central to inflammatory regulation during development of atherosclerosis, is activated by soluble mediators and through biomechanical inputs such as flow-mediated shear- stress. To investigate the molecular mechanisms underlying shear stress mediated signal transduction in vascular cells we have developed a system that applies flow-mediated shear stress in a controlled manner, while inserted in a confocal microscope. In combination with GFP-based methods, this allows continuous monitoring of flow induced signal transduction in live cells and in real time. Flow-mediated shear stress, induced using the system, caused a successive increase in NF-{kappa}B-regulated gene activation. Experiments assessing the mechanisms underlying the NF-{kappa}B induced activity showed time and flow rate dependent effects on the inhibitor, I{kappa}B{alpha}, involving nuclear translocation characterized by a biphasic or cyclic pattern. The effect was observed in both endothelial- and smooth muscle cells, demonstrated to impact noncomplexed I{kappa}B{alpha}, and to involve mechanisms distinct from those mediating cytokine signals. In contrast, effects on the NF-{kappa}B subunit relA were similar to those observed during cytokine stimulation. Further experiments showed the flow induced inter-compartmental transport of I{kappa}B{alpha} to be regulated through the Ras GTP-ase, demonstrating a pronounced reduction in the effects following blocking of Ras activity. These studies show that flow-mediated shear stress, regulated by the Ras GTP-ase, uses distinct mechanisms of NF-{kappa}B control at the molecular level. The oscillatory pattern, reflecting inter-compartmental translocation of I{kappa}B{alpha}, is likely to have fundamental impact on pathway regulation and on development of shear stress-induced distinct vascular cell phenotypes.
    Original languageEnglish
    Pages (from-to)626-634
    Number of pages8
    JournalCirculation Research
    Volume96
    DOIs
    Publication statusPublished - 2005

    Fingerprint

    I-kappa B Proteins
    NF-kappa B
    Guanosine Triphosphate
    Blood Vessels
    Signal Transduction
    Cytokines
    Transcriptional Activation
    Smooth Muscle Myocytes
    Atherosclerosis
    Transcription Factors
    Phenotype

    Keywords

    • shear stress
    • transduction
    • circulation
    • atherosclerosis
    • biomechanics
    • bioengineering
    • medicine
    • cells

    Cite this

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    title = "Distinct NF-kappa B regulation by shear stress through ras-dependent I kappa B alpha oscillations - Real-time analysis of flow-mediated activation in live cells",
    abstract = "NF-{kappa}B, a transcription factor central to inflammatory regulation during development of atherosclerosis, is activated by soluble mediators and through biomechanical inputs such as flow-mediated shear- stress. To investigate the molecular mechanisms underlying shear stress mediated signal transduction in vascular cells we have developed a system that applies flow-mediated shear stress in a controlled manner, while inserted in a confocal microscope. In combination with GFP-based methods, this allows continuous monitoring of flow induced signal transduction in live cells and in real time. Flow-mediated shear stress, induced using the system, caused a successive increase in NF-{kappa}B-regulated gene activation. Experiments assessing the mechanisms underlying the NF-{kappa}B induced activity showed time and flow rate dependent effects on the inhibitor, I{kappa}B{alpha}, involving nuclear translocation characterized by a biphasic or cyclic pattern. The effect was observed in both endothelial- and smooth muscle cells, demonstrated to impact noncomplexed I{kappa}B{alpha}, and to involve mechanisms distinct from those mediating cytokine signals. In contrast, effects on the NF-{kappa}B subunit relA were similar to those observed during cytokine stimulation. Further experiments showed the flow induced inter-compartmental transport of I{kappa}B{alpha} to be regulated through the Ras GTP-ase, demonstrating a pronounced reduction in the effects following blocking of Ras activity. These studies show that flow-mediated shear stress, regulated by the Ras GTP-ase, uses distinct mechanisms of NF-{kappa}B control at the molecular level. The oscillatory pattern, reflecting inter-compartmental translocation of I{kappa}B{alpha}, is likely to have fundamental impact on pathway regulation and on development of shear stress-induced distinct vascular cell phenotypes.",
    keywords = "shear stress, transduction, circulation, atherosclerosis, biomechanics, bioengineering, medicine, cells",
    author = "R. Ganguli and L. Persson and I. Palmer and R. Smallwood and R.A. Black and E. Qwarnstrom",
    year = "2005",
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    Distinct NF-kappa B regulation by shear stress through ras-dependent I kappa B alpha oscillations - Real-time analysis of flow-mediated activation in live cells. / Ganguli, R.; Persson, L.; Palmer, I.; Smallwood, R.; Black, R.A.; Qwarnstrom, E.

    In: Circulation Research, Vol. 96, 2005, p. 626-634.

    Research output: Contribution to journalArticle

    TY - JOUR

    T1 - Distinct NF-kappa B regulation by shear stress through ras-dependent I kappa B alpha oscillations - Real-time analysis of flow-mediated activation in live cells

    AU - Ganguli, R.

    AU - Persson, L.

    AU - Palmer, I.

    AU - Smallwood, R.

    AU - Black, R.A.

    AU - Qwarnstrom, E.

    PY - 2005

    Y1 - 2005

    N2 - NF-{kappa}B, a transcription factor central to inflammatory regulation during development of atherosclerosis, is activated by soluble mediators and through biomechanical inputs such as flow-mediated shear- stress. To investigate the molecular mechanisms underlying shear stress mediated signal transduction in vascular cells we have developed a system that applies flow-mediated shear stress in a controlled manner, while inserted in a confocal microscope. In combination with GFP-based methods, this allows continuous monitoring of flow induced signal transduction in live cells and in real time. Flow-mediated shear stress, induced using the system, caused a successive increase in NF-{kappa}B-regulated gene activation. Experiments assessing the mechanisms underlying the NF-{kappa}B induced activity showed time and flow rate dependent effects on the inhibitor, I{kappa}B{alpha}, involving nuclear translocation characterized by a biphasic or cyclic pattern. The effect was observed in both endothelial- and smooth muscle cells, demonstrated to impact noncomplexed I{kappa}B{alpha}, and to involve mechanisms distinct from those mediating cytokine signals. In contrast, effects on the NF-{kappa}B subunit relA were similar to those observed during cytokine stimulation. Further experiments showed the flow induced inter-compartmental transport of I{kappa}B{alpha} to be regulated through the Ras GTP-ase, demonstrating a pronounced reduction in the effects following blocking of Ras activity. These studies show that flow-mediated shear stress, regulated by the Ras GTP-ase, uses distinct mechanisms of NF-{kappa}B control at the molecular level. The oscillatory pattern, reflecting inter-compartmental translocation of I{kappa}B{alpha}, is likely to have fundamental impact on pathway regulation and on development of shear stress-induced distinct vascular cell phenotypes.

    AB - NF-{kappa}B, a transcription factor central to inflammatory regulation during development of atherosclerosis, is activated by soluble mediators and through biomechanical inputs such as flow-mediated shear- stress. To investigate the molecular mechanisms underlying shear stress mediated signal transduction in vascular cells we have developed a system that applies flow-mediated shear stress in a controlled manner, while inserted in a confocal microscope. In combination with GFP-based methods, this allows continuous monitoring of flow induced signal transduction in live cells and in real time. Flow-mediated shear stress, induced using the system, caused a successive increase in NF-{kappa}B-regulated gene activation. Experiments assessing the mechanisms underlying the NF-{kappa}B induced activity showed time and flow rate dependent effects on the inhibitor, I{kappa}B{alpha}, involving nuclear translocation characterized by a biphasic or cyclic pattern. The effect was observed in both endothelial- and smooth muscle cells, demonstrated to impact noncomplexed I{kappa}B{alpha}, and to involve mechanisms distinct from those mediating cytokine signals. In contrast, effects on the NF-{kappa}B subunit relA were similar to those observed during cytokine stimulation. Further experiments showed the flow induced inter-compartmental transport of I{kappa}B{alpha} to be regulated through the Ras GTP-ase, demonstrating a pronounced reduction in the effects following blocking of Ras activity. These studies show that flow-mediated shear stress, regulated by the Ras GTP-ase, uses distinct mechanisms of NF-{kappa}B control at the molecular level. The oscillatory pattern, reflecting inter-compartmental translocation of I{kappa}B{alpha}, is likely to have fundamental impact on pathway regulation and on development of shear stress-induced distinct vascular cell phenotypes.

    KW - shear stress

    KW - transduction

    KW - circulation

    KW - atherosclerosis

    KW - biomechanics

    KW - bioengineering

    KW - medicine

    KW - cells

    UR - http://dx.doi.org/10.1161/01.RES.0000160435.83210.95

    U2 - 10.1161/01.RES.0000160435.83210.95

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    JO - Circulation Research

    JF - Circulation Research

    SN - 0009-7330

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