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Wang L, Dong S, Chitano P, Seow CY. Potentiation of active force by cyclic strain in sheep carotid arterial smooth muscle. J Appl Physiol (1985) 2023; 135:1243-1254. [PMID: 37823206 DOI: 10.1152/japplphysiol.00162.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Revised: 09/25/2023] [Accepted: 10/09/2023] [Indexed: 10/13/2023] Open
Abstract
The ability to generate force in large arteries is known to be augmented by cyclic strain that mimics the mechanically dynamic in vivo environment associated with blood pressure fluctuation experienced by these arteries. Cyclic strain does not induce a contractile response, like that observed in the myogenic response seen in small arteries, but prompts a substantial increase in the response to electrical stimulation. We coined this phenomenon "force potentiation." Because protein kinase C (PKC) and rho-kinase (ROCK) are known to play a role in increasing contractility of arterial smooth muscle by inhibition of myosin light chain phosphatase, and integrin-link kinase (ILK) is crucial in mechanotransduction, we examined how inhibition of these kinases affected force potentiation in sheep carotid artery. We found that phosphorylation of the regulatory myosin light chain was enhanced by cyclic strain, but the enhancement was observed only in activated, not in relaxed muscle. Inhibition of ROCK diminished force potentiation and active isometric force, likely due to the disinhibition of myosin light chain phosphatase. Inhibition of PKC abolished force potentiation without an effect on active force, suggesting a more exclusive role of PKC (compared with ROCK) in mediating force potentiation. Inhibition of ILK had a similar effect as PKC inhibition, suggesting that ILK may be an upstream kinase for PKC activation by mechanical stimuli. Taken together, the findings suggest that ILK, PKC, and ROCK are important kinases in the signal transduction pathway that mediate the effect of mechanical strain on force potentiation.NEW & NOTEWORTHY When subjected to mechanical strain, smooth muscle from large arteries has the ability to increase its force generation (force potentiation), which could be important in autoregulation of blood pressure. This phenomenon, however, does not involve a myogenic response, such as the one seen in small arteries and arterioles. Our work shows the involvement of ILK, PKC, and ROCK in the signal transduction pathway that mediates the force-potentiating effect of mechanical strain in large arteries.
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Affiliation(s)
- Lu Wang
- Centre for Heart Lung Innovation, St. Paul's Hospital/Providence Health Care, University of British Columbia, Vancouver, British Columbia, Canada
| | - Shoujin Dong
- Department of Respiratory Medicine, Chengdu First People's Hospital, Chengdu, People's Republic of China
| | - Pasquale Chitano
- Centre for Heart Lung Innovation, St. Paul's Hospital/Providence Health Care, University of British Columbia, Vancouver, British Columbia, Canada
| | - Chun Y Seow
- Centre for Heart Lung Innovation, St. Paul's Hospital/Providence Health Care, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, British Columbia, Canada
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2
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Davis MJ, Earley S, Li YS, Chien S. Vascular mechanotransduction. Physiol Rev 2023; 103:1247-1421. [PMID: 36603156 PMCID: PMC9942936 DOI: 10.1152/physrev.00053.2021] [Citation(s) in RCA: 43] [Impact Index Per Article: 43.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 09/26/2022] [Accepted: 10/04/2022] [Indexed: 01/07/2023] Open
Abstract
This review aims to survey the current state of mechanotransduction in vascular smooth muscle cells (VSMCs) and endothelial cells (ECs), including their sensing of mechanical stimuli and transduction of mechanical signals that result in the acute functional modulation and longer-term transcriptomic and epigenetic regulation of blood vessels. The mechanosensors discussed include ion channels, plasma membrane-associated structures and receptors, and junction proteins. The mechanosignaling pathways presented include the cytoskeleton, integrins, extracellular matrix, and intracellular signaling molecules. These are followed by discussions on mechanical regulation of transcriptome and epigenetics, relevance of mechanotransduction to health and disease, and interactions between VSMCs and ECs. Throughout this review, we offer suggestions for specific topics that require further understanding. In the closing section on conclusions and perspectives, we summarize what is known and point out the need to treat the vasculature as a system, including not only VSMCs and ECs but also the extracellular matrix and other types of cells such as resident macrophages and pericytes, so that we can fully understand the physiology and pathophysiology of the blood vessel as a whole, thus enhancing the comprehension, diagnosis, treatment, and prevention of vascular diseases.
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Affiliation(s)
- Michael J Davis
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri
| | - Scott Earley
- Department of Pharmacology, University of Nevada, Reno, Nevada
| | - Yi-Shuan Li
- Department of Bioengineering, University of California, San Diego, California
- Institute of Engineering in Medicine, University of California, San Diego, California
| | - Shu Chien
- Department of Bioengineering, University of California, San Diego, California
- Institute of Engineering in Medicine, University of California, San Diego, California
- Department of Medicine, University of California, San Diego, California
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3
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GsMTx4-D provides protection to the D2.mdx mouse. Neuromuscul Disord 2018; 28:868-877. [PMID: 30174173 DOI: 10.1016/j.nmd.2018.07.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Revised: 07/02/2018] [Accepted: 07/17/2018] [Indexed: 12/23/2022]
Abstract
Duchenne muscular dystrophy is a life-limiting muscle disease that has no current effective therapy. Despite mounting evidence that dysregulation of mechanosensitive ion channels is a significant contributor to dystrophy pathogenesis, effective pharmacologic strategies targeting these channels are lacking. GsMTx4, and its enantiomer GsMTx4-D, are peptide inhibitors of mechanosensitive channels with identical activity. In previous studies, acute in vitro application of GsMTx4 to dystrophic murine muscle effectively reduced the excess MSC dependent calcium influx linked to contraction-induced muscle damage. Here we sought to determine if in vivo treatment with GsMTx4-D proffered benefit in the D2.mdx mouse. GsMTx4-D showed a 1-week half-life when administered by subcutaneous injection over four weeks. Informed by these results, D2.mdx mice were then treated by a subcutaneous injection regimen of GsMTx4-D for six weeks followed by determination of muscle mass, muscle susceptibility to eccentric contraction injury and multiple histological indicators of disease progression. The mice showed a reduction in the loss of muscle mass and a decrease in susceptibility to contraction induced injury. These protective effects were realized without reduction in fibrosis, supporting a model where GsMTx4-D acts directly on muscle cells. We propose GsMTx4-D represents a promising new therapy to slow disease progression and may complement other therapies such as anti-inflammatory agents and gene-replacement strategies.
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DING WENJING, WANG YANG, LI GUOJUN, HANG JIAJI, WU YONGCHANG, LING CHENHAO, ZHOU DANYE, CHEN ZHIBIN, GAO LINGFENG. PIEZORESISTIVE STRAIN SENSOR APPLICATION IN EVALUATION OF MOUSE AORTIC MEDIA CUSHIONS EFFECTIVENESS AND SPONTANEOUS MYOGENIC CONTRACTION. J MECH MED BIOL 2017. [DOI: 10.1142/s0219519417400322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The aortic media realized Windkessel vessel functions and maintain sustained ventricle ejection balance during cardiac circle. Wheatstone bridge circuit piezoresistive strain sensor had desirable sensing properties to investigate aortic cushion features. In this study, Wheatstone bridge sensor was used to evaluate quick stretching-induced aortic efficient cushions and spontaneous myogenic contractions. Mice aortic specimens were loosely hooked and stabilized to [Formula: see text][Formula: see text]mm stainless steel pin and strain sensor, whereas the other side was hooked and shows increasing specimen length. Specimen isometric tension and rhythmic spontaneous myogenic contraction were recorded. Isometric tension and spontaneous myogenic response at initial length ([Formula: see text] and ultimate length ([Formula: see text] were evaluated. Aortic specimen significantly eliminated mechanical rigid oscillations. The recovery to baseline time was significantly shortened at [Formula: see text] ([Formula: see text][Formula: see text]ms and [Formula: see text] ms at [Formula: see text] and [Formula: see text], respectively, but [Formula: see text][Formula: see text]ms and [Formula: see text][Formula: see text]ms in no-load test). High Ca[Formula: see text] incubation prolonged the recovery time to baseline at [Formula: see text] and [Formula: see text] ([Formula: see text][Formula: see text]ms and [Formula: see text][Formula: see text]ms, respectively) and suggested Ca[Formula: see text] decreased efficient cushion. Moreover, strain sensor successfully recorded the enhanced rhythmic spontaneous myogenic contractions in isometric specimen. Wheatstone bridge circuit sensor reflected the significance of efficient cushions under mechanical preload, which absolutely captured rhythmic myogenic contractions of mice aortic specimen.
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Affiliation(s)
- WENJING DING
- Clinical Medicine College, Hai Nan Medical College, No. 3 Cheng Xi Xue Yuan Road, Long Hua District, Hai Kou City, Hai Nan Province 571199, P. R. China
| | - YANG WANG
- Department of Medical Physiology, Hai Nan Medical College, No. 3 Cheng Xi Xue Yuan Road, Long Hua District, Hai Kou City, Hai Nan Province 571199, P. R. China
| | - GUOJUN LI
- Clinical Medicine College, Hai Nan Medical College, No. 3 Cheng Xi Xue Yuan Road, Long Hua District, Hai Kou City, Hai Nan Province 571199, P. R. China
| | - JIAJI HANG
- Clinical Medicine College, Hai Nan Medical College, No. 3 Cheng Xi Xue Yuan Road, Long Hua District, Hai Kou City, Hai Nan Province 571199, P. R. China
| | - YONGCHANG WU
- Clinical Medicine College, Hai Nan Medical College, No. 3 Cheng Xi Xue Yuan Road, Long Hua District, Hai Kou City, Hai Nan Province 571199, P. R. China
| | - CHENHAO LING
- Clinical Medicine College, Hai Nan Medical College, No. 3 Cheng Xi Xue Yuan Road, Long Hua District, Hai Kou City, Hai Nan Province 571199, P. R. China
| | - DANYE ZHOU
- Clinical Medicine College, Hai Nan Medical College, No. 3 Cheng Xi Xue Yuan Road, Long Hua District, Hai Kou City, Hai Nan Province 571199, P. R. China
| | - ZHIBIN CHEN
- Clinical Medicine College, Hai Nan Medical College, No. 3 Cheng Xi Xue Yuan Road, Long Hua District, Hai Kou City, Hai Nan Province 571199, P. R. China
| | - LINGFENG GAO
- Clinical Medicine College, Hai Nan Medical College, No. 3 Cheng Xi Xue Yuan Road, Long Hua District, Hai Kou City, Hai Nan Province 571199, P. R. China
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Leloup A, De Moudt S, Van Hove C, Fransen P. Cyclic Stretch Alters Vascular Reactivity of Mouse Aortic Segments. Front Physiol 2017; 8:858. [PMID: 29163203 PMCID: PMC5674939 DOI: 10.3389/fphys.2017.00858] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Accepted: 10/13/2017] [Indexed: 11/13/2022] Open
Abstract
Large, elastic arteries buffer the pressure wave originating in the left ventricle and are constantly exposed to higher amplitudes of cyclic stretch (10%) than muscular arteries (2%). As a crucial factor for endothelial and smooth muscle cell function, cyclic stretch has, however, never been studied in ex vivo aortic segments of mice. To investigate the effects of cyclic stretch on vaso-reactivity of mouse aortic segments, we used the Rodent Oscillatory Tension Set-up to study Arterial Compliance (ROTSAC). The aortic segments were clamped at frequencies of 6–600 bpm between two variable preloads, thereby mimicking dilation as upon left ventricular systole and recoiling as during diastole. The preloads corresponding to different transmural pressures were chosen to correspond to a low, normal or high amplitude of cyclic stretch. At different time intervals, cyclic stretch was interrupted, the segments were afterloaded and isometric contractions by α1-adrenergic stimulation with 2 μM phenylephrine in the absence and presence of 300 μM L-NAME (eNOS inhibitor) and/or 35 μM diltiazem (blocker of voltage-gated Ca2+ channels) were measured. As compared with static or cyclic stretch at low amplitude (<10 mN) or low frequency (0.1 Hz), cyclic stretch at physiological amplitude (>10 mN) and frequency (1–10 Hz) caused better ex vivo conservation of basal NO release with time after mounting. The relaxation of PE-precontracted segments by addition of ACh to stimulate NO release was unaffected by cyclic stretch. In the absence of basal NO release (hence, presence of L-NAME), physiological in comparison with aberrant cyclic stretch decreased the baseline tension, attenuated the phasic contraction by phenylephrine in the absence of extracellular Ca2+ and shifted the smaller tonic contraction more from a voltage-gated Ca2+ channel-mediated to a non-selective cation channel-mediated. Data highlight the need of sufficient mechanical activation of endothelial and vascular smooth muscle cells to maintain basal NO release and low intracellular Ca2+ in the smooth muscle cells in large arteries. Both phenomena may play a vital role in maintaining the high compliance of large arteries.
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Affiliation(s)
- Arthur Leloup
- Laboratory of Physiopharmacology, Department of Pharmaceutical Sciences, University of Antwerp, Antwerp, Belgium
| | - Sofie De Moudt
- Laboratory of Physiopharmacology, Department of Pharmaceutical Sciences, University of Antwerp, Antwerp, Belgium
| | - Cor Van Hove
- Laboratory of Pharmacology, Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium
| | - Paul Fransen
- Laboratory of Physiopharmacology, Department of Pharmaceutical Sciences, University of Antwerp, Antwerp, Belgium
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Suchyna TM. Piezo channels and GsMTx4: Two milestones in our understanding of excitatory mechanosensitive channels and their role in pathology. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2017; 130:244-253. [PMID: 28778608 DOI: 10.1016/j.pbiomolbio.2017.07.011] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Revised: 07/17/2017] [Accepted: 07/21/2017] [Indexed: 12/19/2022]
Abstract
Discovery of Piezo channels and the reporting of their sensitivity to the inhibitor GsMTx4 were important milestones in the study of non-selective cationic mechanosensitive channels (MSCs) in normal physiology and pathogenesis. GsMTx4 had been used for years to investigate the functional role of cationic MSCs, especially in muscle tissue, but with little understanding of its target or inhibitory mechanism. The sensitivity of Piezo channels to bilayer stress and its robust mechanosensitivity when expressed in heterologous systems were keys to determining GsMTx4's mechanism of action. However, questions remain regarding Piezo's role in muscle function due to the non-selective nature of GsMTx4 inhibition toward membrane mechanoenzymes and the implication of MCS channel types by genetic knockdown. Evidence supporting Piezo like activity, at least in the developmental stages of muscle, is presented. While the MSC targets of GsMTx4 in muscle pathology are unclear, its muscle protective effects are clearly demonstrated in two recent in situ studies on normal cardiomyocytes and dystrophic skeletal muscle. The muscle protective function may be due to the combined effect of GsMTx4's inhibitory action on cationic MSCs like Piezo and TRP, and its potentiation of repolarizing K+ selective MSCs like K2P and SAKCa. Paradoxically, the potent in vitro action of GsMTx4 on many physiological functions seems to conflict with its lack of in situ side-effects on normal animal physiology. Future investigations into cytoskeletal control of sarcolemma mechanics and the suspected inclusion of MSCs in membrane micro/nano sized domains with distinct mechanical properties will aide our understanding of this dichotomy.
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Affiliation(s)
- Thomas M Suchyna
- University of Buffalo, Dept. of Physiology and Biophysics, Buffalo, NY, USA.
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7
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De Moudt S, Leloup A, Van Hove C, De Meyer G, Fransen P. Isometric Stretch Alters Vascular Reactivity of Mouse Aortic Segments. Front Physiol 2017; 8:157. [PMID: 28360864 PMCID: PMC5352655 DOI: 10.3389/fphys.2017.00157] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Accepted: 02/28/2017] [Indexed: 02/02/2023] Open
Abstract
Most vaso-reactive studies in mouse aortic segments are performed in isometric conditions and at an optimal preload, which is the preload corresponding to a maximal contraction by non-receptor or receptor-mediated stimulation. In general, this optimal preload ranges from about 1.2 to 8.0 mN/mm, which according to Laplace's law roughly correlates with transmural pressures of 10-65 mmHg. For physiologic transmural pressures around 100 mmHg, preloads of 15.0 mN/mm should be implemented. The present study aimed to compare vascular reactivity of 2 mm mouse (C57Bl6) aortic segments preloaded at optimal (8.0 mN/mm) vs. (patho) physiological (10.0-32.5 mN/mm) preload. Voltage-dependent contractions of aortic segments, induced by increasing extracellular K+, and contractions by α1-adrenergic stimulation with phenylephrine (PE) were studied at these preloads in the absence and presence of L-NAME to inhibit basal release of NO from endothelial cells (EC). In the absence of basal NO release and with higher than optimal preload, contractions evoked by depolarization or PE were attenuated, whereas in the presence of basal release of NO PE-, but not depolarization-induced contractions were preload-independent. Phasic contractions by PE, as measured in the absence of external Ca2+, were decreased at higher than optimal preload suggestive for a lower contractile SR Ca2+ content at physiological preload. Further, in the presence of external Ca2+, contractions by Ca2+ influx via voltage-dependent Ca2+ channels were preload-independent, whereas non-selective cation channel-mediated contractions were increased. The latter contractions were very sensitive to the basal release of NO, which itself seemed to be preload-independent. Relaxation by endogenous NO (acetylcholine) of aortic segments pre-contracted with PE was preload-independent, whereas relaxation by exogenous NO (diethylamine NONOate) displayed higher sensitivity at high preload. Results indicated that stretching aortic segments to higher than optimal preload depolarizes the SMC and causes Ca2+ unloading of the contractile SR, making them extremely sensitive to small changes in the basal release of NO from EC as can occur in hypertension or arterial stiffening.
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Affiliation(s)
- Sofie De Moudt
- Laboratory of Physiopharmacology, Department of Pharmaceutical Sciences, University of Antwerp Antwerp, Belgium
| | - Arthur Leloup
- Laboratory of Physiopharmacology, Department of Pharmaceutical Sciences, University of Antwerp Antwerp, Belgium
| | - Cor Van Hove
- Laboratory of Pharmacology, Faculty of Medicine and Health Sciences, University of Antwerp Antwerp, Belgium
| | - Guido De Meyer
- Laboratory of Physiopharmacology, Department of Pharmaceutical Sciences, University of Antwerp Antwerp, Belgium
| | - Paul Fransen
- Laboratory of Physiopharmacology, Department of Pharmaceutical Sciences, University of Antwerp Antwerp, Belgium
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8
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Fransen P, Van Hove CE, Leloup AJA, Martinet W, De Meyer GRY, Lemmens K, Bult H, Schrijvers DM. Dissecting out the complex Ca2+-mediated phenylephrine-induced contractions of mouse aortic segments. PLoS One 2015; 10:e0121634. [PMID: 25803863 PMCID: PMC4372603 DOI: 10.1371/journal.pone.0121634] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Accepted: 02/12/2015] [Indexed: 01/04/2023] Open
Abstract
L-type Ca2+ channel (VGCC) mediated Ca2+ influx in vascular smooth muscle cells (VSMC) contributes to the functional properties of large arteries in arterial stiffening and central blood pressure regulation. How this influx relates to steady-state contractions elicited by α1-adrenoreceptor stimulation and how it is modulated by small variations in resting membrane potential (Vm) of VSMC is not clear yet. Here, we show that α1-adrenoreceptor stimulation of aortic segments of C57Bl6 mice with phenylephrine (PE) causes phasic and tonic contractions. By studying the relationship between Ca2+ mobilisation and isometric tension, it was found that the phasic contraction was due to intracellular Ca2+ release and the tonic contraction determined by Ca2+ influx. The latter component involves both Ca2+ influx via VGCC and via non-selective cation channels (NSCC). Influx via VGCC occurs only within the window voltage range of the channel. Modulation of this window Ca2+ influx by small variations of the VSMC Vm causes substantial effects on the contractile performance of aortic segments. The relative contribution of VGCC and NSCC to the contraction by α1-adrenoceptor stimulation could be manipulated by increasing intracellular Ca2+ release from non-contractile sarcoplasmic reticulum Ca2+ stores. Results of this study point to a complex interactions between α1-adrenoceptor-mediated VSMC contractile performance and Ca2+ release form contractile or non-contractile Ca2+ stores with concomitant Ca2+ influx. Given the importance of VGCC and their blockers in arterial stiffening and hypertension, they further point toward an additional role of NSCC (and NSCC blockers) herein.
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Affiliation(s)
- Paul Fransen
- Department of Pharmaceutical Sciences, University of Antwerp, Antwerp, Belgium
- * E-mail:
| | - Cor E. Van Hove
- Department of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium
| | - Arthur J. A. Leloup
- Department of Pharmaceutical Sciences, University of Antwerp, Antwerp, Belgium
| | - Wim Martinet
- Department of Pharmaceutical Sciences, University of Antwerp, Antwerp, Belgium
| | | | - Katrien Lemmens
- Department of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium
| | - Hidde Bult
- Department of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium
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Hayoz S, Cubano L, Maldonado H, Bychkov R. Protein kinase A and C regulate leak potassium currents in freshly isolated vascular myocytes from the aorta. PLoS One 2013; 8:e75077. [PMID: 24086441 PMCID: PMC3781042 DOI: 10.1371/journal.pone.0075077] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Accepted: 08/09/2013] [Indexed: 11/18/2022] Open
Abstract
We tested the hypothesis that protein kinase A (PKA) inhibits K2P currents activated by protein kinase C (PKC) in freshly isolated aortic myocytes. PDBu, the PKC agonist, applied extracellularly, increased the amplitude of the K2P currents in the presence of the “cocktail” of K+ channel blockers. Gö 6976 significantly reduced the increase of the K2P currents by PDBu suggesting the involvement of either α or β isoenzymes of PKC. We found that forskolin, or membrane permeable cAMP, did not inhibit K2P currents activated by the PKC. However, when PKA agonists were added prior to PDBu, they produced a strong decrease in the K2P current amplitudes activated by PKC. Inhibition of PDBu-elicited K2P currents by cAMP agonists was not prevented by the treatment of vascular smooth muscle cells with PKA antagonists (H-89 and Rp-cAMPs). Zn2+ and Hg2+ inhibited K2P currents in one population of cells, produced biphasic responses in another population, and increased the amplitude of the PDBu-elicited K+ currents in a third population of myocytes, suggesting expression of several K2P channel types. We found that cAMP agonists inhibited biphasic responses and increase of amplitude of the PDBu-elicited K2P currents produced by Zn2+ and Hg2. 6-Bnz-cAMp produced a significantly altered pH sensitivity of PDBu-elicited K2P-currents, suggesting the inhibition of alkaline-activated K2P-currents. These results indicate that 6-Bnz-cAMP and other cAMP analogs may inhibit K2P currents through a PKA-independent mechanism. cAMP analogs may interact with unidentified proteins involved in K2P channel regulation. This novel cellular mechanism could provide insights into the interplay between PKC and PKA pathways that regulate vascular tone.
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Affiliation(s)
- Sébastien Hayoz
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan, United States of America
- Department of Pharmacology, Universidad Central Del Caribe, Bayamon, Puerto Rico, United States of America
| | - Luis Cubano
- Department of Pharmacology, Universidad Central Del Caribe, Bayamon, Puerto Rico, United States of America
| | - Hector Maldonado
- Department of Pharmacology, Universidad Central Del Caribe, Bayamon, Puerto Rico, United States of America
| | - Rostislav Bychkov
- Department of Pharmacology, Universidad Central Del Caribe, Bayamon, Puerto Rico, United States of America
- * E-mail:
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10
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van Langen J, Fransen P, Van Hove CE, Schrijvers DM, Martinet W, De Meyer GR, Bult H. Selective loss of basal but not receptor-stimulated relaxation by endothelial nitric oxide synthase after isolation of the mouse aorta. Eur J Pharmacol 2012; 696:111-9. [DOI: 10.1016/j.ejphar.2012.09.016] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2012] [Revised: 09/05/2012] [Accepted: 09/17/2012] [Indexed: 12/21/2022]
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Friedrich O, Wagner S, Battle AR, Schürmann S, Martinac B. Mechano-regulation of the beating heart at the cellular level--mechanosensitive channels in normal and diseased heart. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2012; 110:226-38. [PMID: 22959495 DOI: 10.1016/j.pbiomolbio.2012.08.009] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Accepted: 08/09/2012] [Indexed: 01/22/2023]
Abstract
The heart as a contractile hollow organ finely tunes mechanical parameters such as stroke volume, stroke pressure and cardiac output according to filling volumes, filling pressures via intrinsic and neuronal routes. At the cellular level, cardiomyocytes in beating hearts are exposed to large mechanical stress during successive heart beats. Although the mechanisms of excitation-contraction coupling are well established in mammalian heart cells, the putative contribution of mechanosensitive channels to Ca²⁺ homeostasis, Ca²⁺ signaling and force generation has been primarily investigated in relation to heart disease states. For instance, transient receptor potential channels (TRPs) are up-regulated in animal models of congestive heart failure or hypertension models and seem to play a vital role in pathological Ca²⁺ overload to cardiomyocytes, thus aggravating the pathology of disease at the cellular level. Apart from that, the contribution of mechanosensitive channels (MsC) in the normal beating heart to the downstream force activation cascade has not been addressed. We present an overview of the current literature and concepts of mechanosensitive channel involvement in failing hearts and cardiomyopathies and novel data showing a likely contribution of Ca²⁺ influx via mechanosensitive channels in beating normal cardiomyocytes during systolic shortening.
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Affiliation(s)
- Oliver Friedrich
- Institute of Medical Biotechnology, Friedrich-Alexander-University Erlangen-Nuremberg, Paul-Gordan-Str. 3, 91052 Erlangen, Germany
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12
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Ma Q. Labeled lines meet and talk: population coding of somatic sensations. J Clin Invest 2010; 120:3773-8. [PMID: 21041959 DOI: 10.1172/jci43426] [Citation(s) in RCA: 117] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
The somatic sensory system responds to stimuli of distinct modalities, including touch, pain, itch, and temperature sensitivity. In the past century, great progress has been made in understanding the coding of these sensory modalities. From this work, two major features have emerged. First, there are specific neuronal circuits or labeled lines transmitting specific sensory information from the skin to the brain. Second, the generation of specific sensations often involves crosstalk among distinct labeled lines. These features suggest that population coding is the mechanism underlying somatic sensation.
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Affiliation(s)
- Qiufu Ma
- Dana-Farber Cancer Institute and Department of Neurobiology, Harvard Medical School, Boston, Massachusetts 02115, USA.
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13
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Alonso F, Krattinger N, Mazzolai L, Simon A, Waeber G, Meda P, Haefliger JA. An angiotensin II- and NF-kappaB-dependent mechanism increases connexin 43 in murine arteries targeted by renin-dependent hypertension. Cardiovasc Res 2010; 87:166-76. [PMID: 20110337 PMCID: PMC2883896 DOI: 10.1093/cvr/cvq031] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2009] [Revised: 01/20/2010] [Accepted: 01/25/2010] [Indexed: 01/17/2023] Open
Abstract
AIMS Connexins (Cxs) play a role in the contractility of the aorta wall. We investigated how connexins of the endothelial cells (ECs; Cx37, Cx40) and smooth muscle cells (SMCs; Cx43, Cx45) of the aorta change during renin-dependent and -independent hypertension. METHODS AND RESULTS We subjected both wild-type (WT) mice and mice lacking Cx40 (Cx40(-/-)), to either a two-kidney, one-clip procedure or to N-nitro-l-arginine-methyl-ester treatment, which induce renin-dependent and -independent hypertension, respectively. All hypertensive mice featured a thickened aortic wall, increased levels of Cx37 and Cx45 in SMC, and of Cx40 in EC (except in Cx40(-/-) mice). Cx43 was up-regulated, with no effect on its S368 phosphorylation, only in the SMCs of renin-dependent models of hypertension. Blockade of the renin-angiotensin system of Cx40(-/-) mice normalized blood pressure and prevented both aortic thickening and Cx alterations. Ex vivo exposure of WT aortas, carotids, and mesenteric arteries to physiologically relevant levels of angiotensin II (AngII) increased the levels of Cx43, but not of other Cx. In the aortic SMC line of A7r5 cells, AngII activated kinase-dependent pathways and induced binding of the nuclear factor-kappa B (NF-kappaB) to the Cx43 gene promoter, increasing Cx43 expression. CONCLUSION In both large and small arteries, hypertension differently regulates Cx expression in SMC and EC layers. Cx43 is selectively increased in renin-dependent hypertension via an AngII activation of the extracellular signal-regulated kinase and NF-kappaB pathways.
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MESH Headings
- Angiotensin II/metabolism
- Angiotensin II Type 1 Receptor Blockers/pharmacology
- Angiotensin-Converting Enzyme Inhibitors/pharmacology
- Animals
- Antihypertensive Agents/pharmacology
- Aorta/drug effects
- Aorta/metabolism
- Aorta/physiopathology
- Binding Sites
- Blood Pressure
- Carotid Arteries/metabolism
- Carotid Arteries/physiopathology
- Cell Line
- Connexin 43/genetics
- Connexin 43/metabolism
- Connexins/deficiency
- Connexins/genetics
- Disease Models, Animal
- Endothelial Cells/metabolism
- Extracellular Signal-Regulated MAP Kinases/metabolism
- Genes, Reporter
- Hypertension, Renovascular/drug therapy
- Hypertension, Renovascular/etiology
- Hypertension, Renovascular/metabolism
- Hypertension, Renovascular/physiopathology
- Mesenteric Arteries/metabolism
- Mesenteric Arteries/physiopathology
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Myocytes, Smooth Muscle/metabolism
- NF-kappa B/metabolism
- NG-Nitroarginine Methyl Ester
- Nephrectomy
- Phosphorylation
- Promoter Regions, Genetic
- Rats
- Renin/blood
- Time Factors
- Transfection
- Up-Regulation
- Gap Junction alpha-5 Protein
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Affiliation(s)
- Florian Alonso
- Service of Internal Medicine, Laboratory of Experimental Medicine 19-135S, University Hospital, CHUV-1011 Lausanne, Switzerland
| | - Nathalie Krattinger
- Service of Internal Medicine, Laboratory of Experimental Medicine 19-135S, University Hospital, CHUV-1011 Lausanne, Switzerland
| | - Lucia Mazzolai
- Service of Internal Medicine, Laboratory of Experimental Medicine 19-135S, University Hospital, CHUV-1011 Lausanne, Switzerland
| | - Alexander Simon
- Department of Physiology, College of Medicine, University of Arizona, Tucson, AZ, USA
| | - Gérard Waeber
- Service of Internal Medicine, Laboratory of Experimental Medicine 19-135S, University Hospital, CHUV-1011 Lausanne, Switzerland
| | - Paolo Meda
- Department of Cell Physiology and Metabolism, University of Geneva, School of Medicine, CMU, 1211 Genève 4, Switzerland
| | - Jacques-Antoine Haefliger
- Service of Internal Medicine, Laboratory of Experimental Medicine 19-135S, University Hospital, CHUV-1011 Lausanne, Switzerland
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14
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Hayoz S, Bény JL, Bychkov R. Intracellular cAMP: the "switch" that triggers on "spontaneous transient outward currents" generation in freshly isolated myocytes from thoracic aorta. Am J Physiol Cell Physiol 2006; 292:C1502-9. [PMID: 17192282 DOI: 10.1152/ajpcell.00522.2006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Spontaneous transient outward currents (STOCs) have been reported in resistance and small arteries but have not yet been found in thoracic aorta. Do thoracic aorta myocytes possess cellular machinery that generates STOCs? It was found that the majority of aortic myocytes do not generate STOCs. STOCs were generated in 8.7% of freshly isolated aortic myocytes. Myocytes that did not generate STOCs we have called "silent" myocytes and myocytes with STOCs have been called "active." STOCs recorded in active myocytes were voltage dependent and were inhibited by ryanodine, caffeine, and charybdotoxin. Forskolin was reported to increase STOCs frequency in myocytes isolated from resistance arteries. Forskolin (10 microM) triggered STOCs generation in 35.1% of silent aortic myocytes. In 36.8% percent of silent myocytes, forskolin did not trigger STOCs but increased the amplitude of charybdotoxin-sensitive outward net current to 136.1 +/- 8.5% at 0 mV. Membrane-permeable 8BrcAMP triggered STOCs generation in 38.7% of silent myocytes. Forskolin- or 8BrcAMP-triggered STOCs were inhibited by charybdotoxin. 8BrcAMP also increased open probability of BK(Ca) channels in BAPTA-AM-pretreated cells. Our data demonstrate that, in contrast to resistance arteries, STOCs are present just in the minority of myocytes in the thoracic aorta. However, cellular machinery that generates STOCs can be "switched" on by cAMP. Such an inactive cellular mechanism could modulate the contractility of the thoracic aorta in response to physiological demand.
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Affiliation(s)
- Sébastien Hayoz
- Department of Zoology and Animal Biology, University of Geneva, Sciences III, Geneva, Switzerland
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15
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Abstract
Smooth muscle and endothelial cells in the arterial wall are exposed to mechanical stress. Indeed blood flow induces intraluminal pressure variations and shear stress. An increase in pressure may induce a vessel contraction, a phenomenon known as the myogenic response. Many muscular vessels present vasomotion, i.e., rhythmic diameter oscillations caused by synchronous cytosolic calcium oscillations of the smooth muscle cells. Vasomotion has been shown to be modulated by pressure changes. To get a better understanding of the effect of stress and in particular pressure on vasomotion, we propose a model of a blood vessel describing the calcium dynamics in a coupled population of smooth muscle cells and endothelial cells and the consequent vessel diameter variations. We show that a rise in pressure increases the calcium concentration. This may either induce or abolish vasomotion, or increase its frequency depending on the initial conditions. In our model the myogenic response is less pronounced for large arteries than for small arteries and occurs at higher values of pressure if the wall thickness is increased. Our results are in agreement with experimental observations concerning a broad range of vessels.
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Affiliation(s)
- Michèle Koenigsberger
- Ecole Polytechnique Fédérale de Lausanne, Laboratory of Cell Biophysics, Lausanne, Switzerland.
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