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Martín-Aragón Baudel M, Flores-Tamez VA, Hong J, Reddy GR, Maillard P, Burns AE, Man KNM, Sasse KC, Ward SM, Catterall WA, Bers DM, Hell JW, Nieves-Cintrón M, Navedo MF. Spatiotemporal Control of Vascular Ca V1.2 by α1 C S1928 Phosphorylation. Circ Res 2022; 131:1018-1033. [PMID: 36345826 PMCID: PMC9722584 DOI: 10.1161/circresaha.122.321479] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2022] [Revised: 10/13/2022] [Accepted: 10/27/2022] [Indexed: 11/10/2022]
Abstract
BACKGROUND L-type CaV1.2 channels undergo cooperative gating to regulate cell function, although mechanisms are unclear. This study tests the hypothesis that phosphorylation of the CaV1.2 pore-forming subunit α1C at S1928 mediates vascular CaV1.2 cooperativity during diabetic hyperglycemia. METHODS A multiscale approach including patch-clamp electrophysiology, super-resolution nanoscopy, proximity ligation assay, calcium imaging' pressure myography, and Laser Speckle imaging was implemented to examine CaV1.2 cooperativity, α1C clustering, myogenic tone, and blood flow in human and mouse arterial myocytes/vessels. RESULTS CaV1.2 activity and cooperative gating increase in arterial myocytes from patients with type 2 diabetes and type 1 diabetic mice, and in wild-type mouse arterial myocytes after elevating extracellular glucose. These changes were prevented in wild-type cells pre-exposed to a PKA inhibitor or cells from knock-in S1928A but not S1700A mice. In addition, α1C clustering at the surface membrane of wild-type, but not wild-type cells pre-exposed to PKA or P2Y11 inhibitors and S1928A arterial myocytes, was elevated upon hyperglycemia and diabetes. CaV1.2 spatial and gating remodeling correlated with enhanced arterial myocyte Ca2+ influx and contractility and in vivo reduction in arterial diameter and blood flow upon hyperglycemia and diabetes in wild-type but not S1928A cells/mice. CONCLUSIONS These results suggest that PKA-dependent S1928 phosphorylation promotes the spatial reorganization of vascular α1C into "superclusters" upon hyperglycemia and diabetes. This triggers CaV1.2 activity and cooperativity, directly impacting vascular reactivity. The results may lay the foundation for developing therapeutics to correct CaV1.2 and arterial function during diabetic hyperglycemia.
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Affiliation(s)
- Miguel Martín-Aragón Baudel
- Department of Pharmacology, University of California Davis, Davis, CA (M.M.-A.B., V.A.F.-T., J.H., G.R.R., A.E.B., K.N.M.M., D.M.B., J.W.H., M.N.-C., M.F.N.)
| | - Victor A. Flores-Tamez
- Department of Pharmacology, University of California Davis, Davis, CA (M.M.-A.B., V.A.F.-T., J.H., G.R.R., A.E.B., K.N.M.M., D.M.B., J.W.H., M.N.-C., M.F.N.)
| | - Junyoung Hong
- Department of Pharmacology, University of California Davis, Davis, CA (M.M.-A.B., V.A.F.-T., J.H., G.R.R., A.E.B., K.N.M.M., D.M.B., J.W.H., M.N.-C., M.F.N.)
| | - Gopyreddy R. Reddy
- Department of Pharmacology, University of California Davis, Davis, CA (M.M.-A.B., V.A.F.-T., J.H., G.R.R., A.E.B., K.N.M.M., D.M.B., J.W.H., M.N.-C., M.F.N.)
| | - Pauline Maillard
- Department of Neurology, University of California Davis, Davis, CA (P.M.)
| | - Abby E. Burns
- Department of Pharmacology, University of California Davis, Davis, CA (M.M.-A.B., V.A.F.-T., J.H., G.R.R., A.E.B., K.N.M.M., D.M.B., J.W.H., M.N.-C., M.F.N.)
| | - Kwun Nok Mimi Man
- Department of Pharmacology, University of California Davis, Davis, CA (M.M.-A.B., V.A.F.-T., J.H., G.R.R., A.E.B., K.N.M.M., D.M.B., J.W.H., M.N.-C., M.F.N.)
| | | | - Sean M. Ward
- Department of Physiology and Cell Biology, University of Nevada Reno, Reno, NV (S.M.W.)
| | | | - Donald M. Bers
- Department of Pharmacology, University of California Davis, Davis, CA (M.M.-A.B., V.A.F.-T., J.H., G.R.R., A.E.B., K.N.M.M., D.M.B., J.W.H., M.N.-C., M.F.N.)
| | - Johannes W. Hell
- Department of Pharmacology, University of California Davis, Davis, CA (M.M.-A.B., V.A.F.-T., J.H., G.R.R., A.E.B., K.N.M.M., D.M.B., J.W.H., M.N.-C., M.F.N.)
| | - Madeline Nieves-Cintrón
- Department of Pharmacology, University of California Davis, Davis, CA (M.M.-A.B., V.A.F.-T., J.H., G.R.R., A.E.B., K.N.M.M., D.M.B., J.W.H., M.N.-C., M.F.N.)
| | - Manuel F. Navedo
- Department of Pharmacology, University of California Davis, Davis, CA (M.M.-A.B., V.A.F.-T., J.H., G.R.R., A.E.B., K.N.M.M., D.M.B., J.W.H., M.N.-C., M.F.N.)
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Dixon RE, Navedo MF, Binder MD, Santana LF. Mechanisms and Physiological Implications of Cooperative Gating of Ion Channels Clusters. Physiol Rev 2021; 102:1159-1210. [PMID: 34927454 DOI: 10.1152/physrev.00022.2021] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Ion channels play a central role in the regulation of nearly every cellular process. Dating back to the classic 1952 Hodgkin-Huxley model of the generation of the action potential, ion channels have always been thought of as independent agents. A myriad of recent experimental findings exploiting advances in electrophysiology, structural biology, and imaging techniques, however, have posed a serious challenge to this long-held axiom as several classes of ion channels appear to open and close in a coordinated, cooperative manner. Ion channel cooperativity ranges from variable-sized oligomeric cooperative gating in voltage-gated, dihydropyridine-sensitive Cav1.2 and Cav1.3 channels to obligatory dimeric assembly and gating of voltage-gated Nav1.5 channels. Potassium channels, transient receptor potential channels, hyperpolarization cyclic nucleotide-activated channels, ryanodine receptors (RyRs), and inositol trisphosphate receptors (IP3Rs) have also been shown to gate cooperatively. The implications of cooperative gating of these ion channels range from fine tuning excitation-contraction coupling in muscle cells to regulating cardiac function and vascular tone, to modulation of action potential and conduction velocity in neurons and cardiac cells, and to control of pace-making activity in the heart. In this review, we discuss the mechanisms leading to cooperative gating of ion channels, their physiological consequences and how alterations in cooperative gating of ion channels may induce a range of clinically significant pathologies.
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Affiliation(s)
- Rose Ellen Dixon
- Department of Physiology and Membrane Biology, University of California, Davis, CA, United States
| | - Manuel F Navedo
- Department of Pharmacology, University of California, Davis, CA, United States
| | - Marc D Binder
- Department of Physiology and Biophysics, University of Washington, Seattle, WA, United States
| | - L Fernando Santana
- Department of Physiology and Membrane Biology, University of California, Davis, CA, United States
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Nieves-Cintron M, Santana LF, Navedo MF. TRPML1ng on sparks. Sci Signal 2020; 13:13/637/eabc0993. [PMID: 32576679 DOI: 10.1126/scisignal.abc0993] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
In this issue of Science Signaling, Thakore et al. report that the Ca2+-permeable channel TRPML1 closely associates with ryanodine receptors to induce Ca2+ sparks in native arterial myocytes. Functional studies revealed a key role for TRPML1 channels in regulation of arterial myocyte contractility and blood pressure.
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Affiliation(s)
| | - Luis F Santana
- Department of Physiology and Membrane Biology, University of California Davis, Davis, CA 95616, USA
| | - Manuel F Navedo
- Department of Pharmacology, University of California Davis, Davis, CA 95616, USA.
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4
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Ito DW, Hannigan KI, Ghosh D, Xu B, Del Villar SG, Xiang YK, Dickson EJ, Navedo MF, Dixon RE. β-adrenergic-mediated dynamic augmentation of sarcolemmal Ca V 1.2 clustering and co-operativity in ventricular myocytes. J Physiol 2019; 597:2139-2162. [PMID: 30714156 PMCID: PMC6462464 DOI: 10.1113/jp277283] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Accepted: 02/03/2019] [Indexed: 01/25/2023] Open
Abstract
Key points Prevailing dogma holds that activation of the β‐adrenergic receptor/cAMP/protein kinase A signalling pathway leads to enhanced L‐type CaV1.2 channel activity, resulting in increased Ca2+ influx into ventricular myocytes and a positive inotropic response. However, the full mechanistic and molecular details underlying this phenomenon are incompletely understood. CaV1.2 channel clusters decorate T‐tubule sarcolemmas of ventricular myocytes. Within clusters, nanometer proximity between channels permits Ca2+‐dependent co‐operative gating behaviour mediated by physical interactions between adjacent channel C‐terminal tails. We report that stimulation of cardiomyocytes with isoproterenol, evokes dynamic, protein kinase A‐dependent augmentation of CaV1.2 channel abundance along cardiomyocyte T‐tubules, resulting in the appearance of channel ‘super‐clusters’, and enhanced channel co‐operativity that amplifies Ca2+ influx. On the basis of these data, we suggest a new model in which a sub‐sarcolemmal pool of pre‐synthesized CaV1.2 channels resides in cardiomyocytes and can be mobilized to the membrane in times of high haemodynamic or metabolic demand, to tune excitation–contraction coupling.
Abstract Voltage‐dependent L‐type CaV1.2 channels play an indispensable role in cardiac excitation–contraction coupling. Activation of the β‐adrenergic receptor (βAR)/cAMP/protein kinase A (PKA) signalling pathway leads to enhanced CaV1.2 activity, resulting in increased Ca2+ influx into ventricular myocytes and a positive inotropic response. CaV1.2 channels exhibit a clustered distribution along the T‐tubule sarcolemma of ventricular myocytes where nanometer proximity between channels permits Ca2+‐dependent co‐operative gating behaviour mediated by dynamic, physical, allosteric interactions between adjacent channel C‐terminal tails. This amplifies Ca2+ influx and augments myocyte Ca2+ transient and contraction amplitudes. We investigated whether βAR signalling could alter CaV1.2 channel clustering to facilitate co‐operative channel interactions and elevate Ca2+ influx in ventricular myocytes. Bimolecular fluorescence complementation experiments reveal that the βAR agonist, isoproterenol (ISO), promotes enhanced CaV1.2–CaV1.2 physical interactions. Super‐resolution nanoscopy and dynamic channel tracking indicate that these interactions are expedited by enhanced spatial proximity between channels, resulting in the appearance of CaV1.2 ‘super‐clusters’ along the z‐lines of ISO‐stimulated cardiomyocytes. The mechanism that leads to super‐cluster formation involves rapid, dynamic augmentation of sarcolemmal CaV1.2 channel abundance after ISO application. Optical and electrophysiological single channel recordings confirm that these newly inserted channels are functional and contribute to overt co‐operative gating behaviour of CaV1.2 channels in ISO stimulated myocytes. The results of the present study reveal a new facet of βAR‐mediated regulation of CaV1.2 channels in the heart and support the novel concept that a pre‐synthesized pool of sub‐sarcolemmal CaV1.2 channel‐containing vesicles/endosomes resides in cardiomyocytes and can be mobilized to the sarcolemma to tune excitation–contraction coupling to meet metabolic and/or haemodynamic demands. Prevailing dogma holds that activation of the β‐adrenergic receptor/cAMP/protein kinase A signalling pathway leads to enhanced L‐type CaV1.2 channel activity, resulting in increased Ca2+ influx into ventricular myocytes and a positive inotropic response. However, the full mechanistic and molecular details underlying this phenomenon are incompletely understood. CaV1.2 channel clusters decorate T‐tubule sarcolemmas of ventricular myocytes. Within clusters, nanometer proximity between channels permits Ca2+‐dependent co‐operative gating behaviour mediated by physical interactions between adjacent channel C‐terminal tails. We report that stimulation of cardiomyocytes with isoproterenol, evokes dynamic, protein kinase A‐dependent augmentation of CaV1.2 channel abundance along cardiomyocyte T‐tubules, resulting in the appearance of channel ‘super‐clusters’, and enhanced channel co‐operativity that amplifies Ca2+ influx. On the basis of these data, we suggest a new model in which a sub‐sarcolemmal pool of pre‐synthesized CaV1.2 channels resides in cardiomyocytes and can be mobilized to the membrane in times of high haemodynamic or metabolic demand, to tune excitation–contraction coupling.
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Affiliation(s)
- Danica W Ito
- Department of Physiology & Membrane Biology, University of California Davis, Davis, CA, USA
| | - Karen I Hannigan
- Department of Physiology & Membrane Biology, University of California Davis, Davis, CA, USA
| | - Debapriya Ghosh
- Department of Pharmacology, University of California Davis, Davis, CA, USA
| | - Bing Xu
- Department of Pharmacology, University of California Davis, Davis, CA, USA
| | - Silvia G Del Villar
- Department of Physiology & Membrane Biology, University of California Davis, Davis, CA, USA
| | - Yang K Xiang
- Department of Pharmacology, University of California Davis, Davis, CA, USA.,VA Northern California Health Care System, Mather, CA, USA
| | - Eamonn J Dickson
- Department of Physiology & Membrane Biology, University of California Davis, Davis, CA, USA
| | - Manuel F Navedo
- Department of Pharmacology, University of California Davis, Davis, CA, USA
| | - Rose E Dixon
- Department of Physiology & Membrane Biology, University of California Davis, Davis, CA, USA
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Ghosh D, Nieves-Cintrón M, Tajada S, Brust-Mascher I, Horne MC, Hell JW, Dixon RE, Santana LF, Navedo MF. Dynamic L-type Ca V1.2 channel trafficking facilitates Ca V1.2 clustering and cooperative gating. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2018; 1865:1341-1355. [PMID: 29959960 PMCID: PMC6407617 DOI: 10.1016/j.bbamcr.2018.06.013] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 06/22/2018] [Accepted: 06/26/2018] [Indexed: 11/21/2022]
Abstract
L-type CaV1.2 channels are key regulators of gene expression, cell excitability and muscle contraction. CaV1.2 channels organize in clusters throughout the plasma membrane. This channel organization has been suggested to contribute to the concerted activation of adjacent CaV1.2 channels (e.g. cooperative gating). Here, we tested the hypothesis that dynamic intracellular and perimembrane trafficking of CaV1.2 channels is critical for formation and dissolution of functional channel clusters mediating cooperative gating. We found that CaV1.2 moves in vesicular structures of circular and tubular shape with diverse intracellular and submembrane trafficking patterns. Both microtubules and actin filaments are required for dynamic movement of CaV1.2 vesicles. These vesicles undergo constitutive homotypic fusion and fission events that sustain CaV1.2 clustering, channel activity and cooperative gating. Our study suggests that CaV1.2 clusters and activity can be modulated by diverse and unique intracellular and perimembrane vesicular dynamics to fine-tune Ca2+ signals.
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Affiliation(s)
- Debapriya Ghosh
- Department of Pharmacology, School of Medicine, One Shields Avenue, University of California, Davis, CA 95616, USA
| | - Madeline Nieves-Cintrón
- Department of Pharmacology, School of Medicine, One Shields Avenue, University of California, Davis, CA 95616, USA
| | - Sendoa Tajada
- Department of Physiology & Membrane Biology, School of Medicine, One Shields Avenue, University of California, Davis, CA 95616, USA
| | - Ingrid Brust-Mascher
- Advanced Imaging Facility, School of Veterinary Medicine, One Shields Avenue, University of California, Davis, CA 95616, USA
| | - Mary C Horne
- Department of Pharmacology, School of Medicine, One Shields Avenue, University of California, Davis, CA 95616, USA
| | - Johannes W Hell
- Department of Pharmacology, School of Medicine, One Shields Avenue, University of California, Davis, CA 95616, USA
| | - Rose E Dixon
- Department of Physiology & Membrane Biology, School of Medicine, One Shields Avenue, University of California, Davis, CA 95616, USA
| | - Luis F Santana
- Department of Physiology & Membrane Biology, School of Medicine, One Shields Avenue, University of California, Davis, CA 95616, USA
| | - Manuel F Navedo
- Department of Pharmacology, School of Medicine, One Shields Avenue, University of California, Davis, CA 95616, USA.
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6
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Tajada S, Moreno CM, O'Dwyer S, Woods S, Sato D, Navedo MF, Santana LF. Distance constraints on activation of TRPV4 channels by AKAP150-bound PKCα in arterial myocytes. J Gen Physiol 2017; 149:639-659. [PMID: 28507079 PMCID: PMC5460949 DOI: 10.1085/jgp.201611709] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Revised: 03/03/2017] [Accepted: 04/27/2017] [Indexed: 11/20/2022] Open
Abstract
Vascular smooth muscle tone can be regulated by angiotensin II, which enhances TRPV4 channel activity via AKAP150-bound protein kinase C. Tajada et al. show that the effect of AKAP150 on TRPV4 channels is inversely proportional to the distance between them, which varies with sex and arterial bed. TRPV4 (transient receptor potential vanilloid 4) channels are Ca2+-permeable channels that play a key role in regulating vascular tone. In arterial myocytes, opening of TRPV4 channels creates local increases in Ca2+ influx, detectable optically as “TRPV4 sparklets.” TRPV4 sparklet activity can be enhanced by the action of the vasoconstrictor angiotensin II (AngII). This modulation depends on the activation of subcellular signaling domains that comprise protein kinase C α (PKCα) bound to the anchoring protein AKAP150. Here, we used super-resolution nanoscopy, patch-clamp electrophysiology, Ca2+ imaging, and mathematical modeling approaches to test the hypothesis that AKAP150-dependent modulation of TRPV4 channels is critically dependent on the distance between these two proteins in the sarcolemma of arterial myocytes. Our data show that the distance between AKAP150 and TRPV4 channel clusters varies with sex and arterial bed. Consistent with our hypothesis, we further find that basal and AngII-induced TRPV4 channel activity decays exponentially as the distance between TRPV4 and AKAP150 increases. Our data suggest a maximum radius of action of ∼200 nm for local modulation of TRPV4 channels by AKAP150-associated PKCα.
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Affiliation(s)
- Sendoa Tajada
- Department of Physiology and Membrane Biology, University of California Davis School of Medicine, Davis, CA
| | - Claudia M Moreno
- Department of Physiology and Membrane Biology, University of California Davis School of Medicine, Davis, CA
| | - Samantha O'Dwyer
- Department of Physiology and Membrane Biology, University of California Davis School of Medicine, Davis, CA
| | - Sean Woods
- Department of Physiology and Membrane Biology, University of California Davis School of Medicine, Davis, CA
| | - Daisuke Sato
- Department of Pharmacology, University of California Davis School of Medicine, Davis, CA
| | - Manuel F Navedo
- Department of Pharmacology, University of California Davis School of Medicine, Davis, CA
| | - L Fernando Santana
- Department of Physiology and Membrane Biology, University of California Davis School of Medicine, Davis, CA
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Ghosh D, Syed AU, Prada MP, Nystoriak MA, Santana LF, Nieves-Cintrón M, Navedo MF. Calcium Channels in Vascular Smooth Muscle. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2016; 78:49-87. [PMID: 28212803 DOI: 10.1016/bs.apha.2016.08.002] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Calcium (Ca2+) plays a central role in excitation, contraction, transcription, and proliferation of vascular smooth muscle cells (VSMs). Precise regulation of intracellular Ca2+ concentration ([Ca2+]i) is crucial for proper physiological VSM function. Studies over the last several decades have revealed that VSMs express a variety of Ca2+-permeable channels that orchestrate a dynamic, yet finely tuned regulation of [Ca2+]i. In this review, we discuss the major Ca2+-permeable channels expressed in VSM and their contribution to vascular physiology and pathology.
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Affiliation(s)
- D Ghosh
- University of California, Davis, CA, United States
| | - A U Syed
- University of California, Davis, CA, United States
| | - M P Prada
- University of California, Davis, CA, United States
| | - M A Nystoriak
- Diabetes and Obesity Center, University of Louisville, Louisville, KY, United States
| | - L F Santana
- University of California, Davis, CA, United States
| | | | - M F Navedo
- University of California, Davis, CA, United States.
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Beltrán C, Treviño CL, Mata-Martínez E, Chávez JC, Sánchez-Cárdenas C, Baker M, Darszon A. Role of Ion Channels in the Sperm Acrosome Reaction. SPERM ACROSOME BIOGENESIS AND FUNCTION DURING FERTILIZATION 2016; 220:35-69. [DOI: 10.1007/978-3-319-30567-7_3] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Abstract
Total internal reflection fluorescence (TIRF) microscopy is a powerful tool for visualizing near-membrane cellular structures and processes, including imaging of local Ca2+ transients with single-channel resolution. TIRF is most commonly implemented in epi-fluorescence mode, whereby laser excitation light is introduced at a spot near the periphery of the back focal plane of a high numerical aperture objective lens. However, this approach results in an irregular illumination field, owing to interference fringes and scattering and shadowing by cellular structures. We describe a simple system to circumvent these limitations, utilizing a pair of galvanometer-driven mirrors to rapidly spin the laser spot in a circle at the back focal plane of the objective lens, so that irregularities average out during each camera exposure to produce an effectively uniform field. Computer control of the mirrors enables precise scanning at 200 Hz (5ms camera exposure times) or faster, and the scan radius can be altered on a frame-by-frame basis to achieve near-simultaneous imaging in TIRF, widefield and ‘skimming plane’ imaging modes. We demonstrate the utility of the system for dynamic recording of local inositol trisphosphate-mediated Ca2+ signals and for imaging the redistribution of STIM and Orai proteins during store-operated Ca2+ entry. We further anticipate that it will be readily applicable for numerous other near-membrane studies, especially those involving fast dynamic processes.
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10
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Nieves-Cintrón M, Nystoriak MA, Prada MP, Johnson K, Fayer W, Dell'Acqua ML, Scott JD, Navedo MF. Selective down-regulation of KV2.1 function contributes to enhanced arterial tone during diabetes. J Biol Chem 2015; 290:7918-29. [PMID: 25670860 DOI: 10.1074/jbc.m114.622811] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Enhanced arterial tone is a leading cause of vascular complications during diabetes. Voltage-gated K(+) (KV) channels are key regulators of vascular smooth muscle cells (VSMCs) contractility and arterial tone. Whether impaired KV channel function contributes to enhance arterial tone during diabetes is unclear. Here, we demonstrate a reduction in KV-mediated currents (IKv) in VSMCs from a high fat diet (HFD) mouse model of type 2 diabetes. In particular, IKv sensitive to stromatoxin (ScTx), a potent KV2 blocker, were selectively reduced in diabetic VSMCs. This was associated with decreased KV2-mediated regulation of arterial tone and suppression of the KV2.1 subunit mRNA and protein in VSMCs/arteries isolated from HFD mice. We identified protein kinase A anchoring protein 150 (AKAP150), via targeting of the phosphatase calcineurin (CaN), and the transcription factor nuclear factor of activated T-cells c3 (NFATc3) as required determinants of KV2.1 suppression during diabetes. Interestingly, substantial reduction in transcript levels for KV2.1 preceded down-regulation of large conductance Ca(2+)-activated K(+) (BKCa) channel β1 subunits, which are ultimately suppressed in chronic hyperglycemia to a similar extent. Together, our study supports the concept that transcriptional suppression of KV2.1 by activation of the AKAP150-CaN/NFATc3 signaling axis contributes to enhanced arterial tone during diabetes.
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Affiliation(s)
| | - Matthew A Nystoriak
- From the Department of Pharmacology, University of California, Davis, California 95616
| | - Maria Paz Prada
- From the Department of Pharmacology, University of California, Davis, California 95616
| | - Kenneth Johnson
- From the Department of Pharmacology, University of California, Davis, California 95616
| | - William Fayer
- From the Department of Pharmacology, University of California, Davis, California 95616
| | - Mark L Dell'Acqua
- the Department of Pharmacology, University of Colorado, Denver, Colorado 80045, and
| | - John D Scott
- the Howard Hughes Medical Institute and Department of Pharmacology, University of Washington, Seattle, Washington 98195
| | - Manuel F Navedo
- From the Department of Pharmacology, University of California, Davis, California 95616,
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