Integrin-mediated mechanotransduction in renal vascular smooth muscle cells: activation of calcium sparks

2007 ◽  
Vol 293 (4) ◽  
pp. R1586-R1594 ◽  
Author(s):  
Lavanya Balasubramanian ◽  
Abu Ahmed ◽  
Chun-Min Lo ◽  
James S. K. Sham ◽  
Kay-Pong Yip
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Vascular Smooth Muscle Cells ◽  
Muscle Cells ◽  
Mechanical Force ◽  
Binding Peptide ◽  
Intracellular Ca ◽  
Afferent Arterioles ◽  
Paramagnetic Beads

Integrins are transmembrane heterodimeric proteins that link extracellular matrix (ECM) to cytoskeleton and have been shown to function as mechanotransducers in nonmuscle cells. Synthetic integrin-binding peptide triggers Ca2+ mobilization and contraction in vascular smooth muscle cells (VSMCs) of rat afferent arteriole, indicating that interactions between the ECM and integrins modulate vascular tone. To examine whether integrins transduce extracellular mechanical stress into intracellular Ca2+ signaling events in VSMCs, unidirectional mechanical force was applied to freshly isolated renal VSMCs through paramagnetic beads coated with fibronectin (natural ligand of α5β1-integrin in VSMCs). Pulling of fibronectin-coated beads with an electromagnet triggered Ca2+ sparks, followed by global Ca2+ mobilization. Paramagnetic beads coated with low-density lipoprotein, whose receptors are not linked to cytoskeleton, were minimally effective in triggering Ca2+ sparks and global Ca2+ mobilization. Preincubation with ryanodine, cytochalasin-D, or colchicine substantially reduced the occurrence of Ca2+ sparks triggered by fibronectin-coated beads. Binding of VSMCs with antibodies specific to the extracellular domains of α5- and β1-integrins triggered Ca2+ sparks simulating the effects of fibronectin-coated beads. Preincubation of microperfused afferent arterioles with ryanodine or integrin-specific binding peptide inhibited pressure-induced myogenic constriction. In conclusion, integrins transduce mechanical force into intracellular Ca2+ signaling events in renal VSMCs. Integrin-mediated mechanotransduction is probably involved in myogenic response of afferent arterioles.

Ets-1 is an early response gene activated by ET-1 and PDGF-BB in vascular smooth muscle cells

1998 ◽  
Vol 274 (2) ◽  
pp. C472-C480 ◽  
Author(s):  
Shinji Naito ◽  
Shunichi Shimizu ◽  
Shigeto Maeda ◽  
Jianwei Wang ◽  
Richard Paul ◽  
...  
Keyword(s):  
Gene Expression ◽  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Vascular Smooth Muscle Cells ◽  
Inositol Phosphate ◽  
Muscle Cells ◽  
Tetraacetic Acid ◽  
Acetoxymethyl Ester ◽  
Intracellular Ca

Ets-1 is a transcription factor that activates expression of matrix-degrading proteinases such as collagenase and stromelysin. To study the control of ets-1 gene expression in rat vascular smooth muscle cells (VSMC), cells were exposed to factors known to regulate VSMC migration and proliferation. Platelet-derived growth factor-BB (PDGF-BB), endothelin-1 (ET-1), and phorbol 12-myristate 13-acetate (PMA) induced a dose-dependent expression of ets-1 mRNA. These effects were abrogated by inhibition of protein kinase C (PKC) by H-7 or chronic PMA treatment. Ets-1 mRNA was superinduced by PDGF-BB and ET-1 in the presence of cycloheximide. The chelation of intracellular Ca2+ by 1,2-bis(2-aminophenoxy)ethane- N, N, N′, N′-tetraacetic acid-acetoxymethyl ester and the depletion of endoplasmic reticulum intracellular Ca2+concentration ([Ca2+]i) by thapsigargin inhibited PDGF-BB- and ET-1-induced ets-1 mRNA, whereas ethylene glycol-bis(β-aminoethyl ether)- N, N, N′, N′-tetraacetic acid had no effect. However, [Ca2+]irelease alone was not sufficient to increase ets-1 mRNA. Forskolin blocked ET-1-, PDGF-BB-, and PMA-induced ets-1 mRNA, as well as inositol phosphate formation, consistent with an effect through impairment of PKC activation. Inhibitors of ets-1 gene expression, such as H-7 and herbimycin A, inhibited the ET-1 induction of collagenase I mRNA. We propose that ets-1 may be an important element in the orchestration of matrix proteinase expression and of vascular remodeling after arterial injury.

Attenuation of the serotonin-induced increase in intracellular calcium in rat aortic smooth muscle cells by sarpogrelate

2003 ◽  
Vol 81 (11) ◽  
pp. 1056-1063 ◽  
Author(s):  
Harjot K Saini ◽  
Sushil K Sharma ◽  
Peter Zahradka ◽  
Hideo Kumamoto ◽  
Nobuakira Takeda ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Vascular Smooth Muscle Cells ◽  
Muscle Cells ◽  
Dependent Manner ◽  
Aortic Smooth Muscle Cells ◽  
Aortic Smooth Muscle ◽  
Receptor Sites ◽  
Intracellular Ca

Although serotonin (5-HT) induced proliferation of vascular smooth muscle cells is considered to involve changes in intracellular Ca2+ ([Ca2+]i), the mechanism of Ca2+ mobilization by 5-HT is not well defined. In this study, we examined the effect of 5-HT on rat aortic smooth muscle cells (RASMCs) by Fura-2 microfluorometry for [Ca2+]i measurements. 5-HT was observed to increase the [Ca2+]i in a concentration- and time-dependent manner. This action of 5-HT was dependent upon the extracellular concentration of Ca2+ ([Ca2+]e) and was inhibited by both Ca2+ channel antagonists (verapamil and diltiazem) and inhibitors of sarcoplasmic reticular Ca2+ pumps (thapsigargin and cyclopia zonic acid). The 5-HT-induced increase in [Ca2+]i was blocked by sarpogrelate, a 5-HT2A-receptor antagonist, but not by different agents known to block other receptor sites. 5-HT-receptor antagonists such as ketanserin, cinanserin, and mianserin, unlike methysergide, were also found to inhibit the 5-HT-induced Ca2+ mobilization, but these agents were less effective in comparison to sarpogrelate. On the other hand, the increase in [Ca2+]i in RASMCs by ATP, angiotensin II, endothelin-1, or phorbol ester was not affected by sarpogrelate. These results indicate that Ca2+ mobilization in RASMCs by 5-HT is mediated through the activation of 5-HT2A receptors and support the view that the 5-HT-induced increase in [Ca2+]i involves both the extracellular and intracellular sources of Ca2+.Key words: sarpogrelate, serotonin, vascular smooth muscle cells, intracellular Ca2+.

Integrin mobilizes intracellular Ca2+ in renal vascular smooth muscle cells

2001 ◽  
Vol 280 (3) ◽  
pp. C593-C603 ◽  
Author(s):  
Wah-Lun Chan ◽  
N.-H. Holstein-Rathlou ◽  
Kay-Pong Yip
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Vascular Smooth Muscle Cells ◽  
Muscle Cells ◽  
Initial Response ◽  
Rgd Peptides ◽  
Intracellular Ca ◽  
Functional Blocking ◽  
Renal Vascular

Peptides with the Arg-Gly-Asp (RGD) motif induce vasoconstriction in rat afferent arterioles by increasing the intracellular Ca2+ concentration ([Ca2+]i) in vascular smooth muscle cells (VSMC). This finding suggests that occupancy of integrins on the plasma membrane of VSMC might affect vascular tone. The purpose of this study was to determine whether occupancy of integrins by exogenous RGD peptides initiates intracellular Ca2+ signaling in cultured renal VSMC. When smooth muscle cells were exposed to 0.1 mM hexapeptide GRGDSP, [Ca2+]i rapidly increased from 91 ± 4 to 287 ± 37 nM and then returned to the baseline within 20 s (P < 0.05, 34 cells/5 coverslips). In controls, the hexapeptide GRGESP did not trigger Ca2+mobilization. Local application of the GRGDSP induced a regional increase of cytoplasmic [Ca2+]i, which propagated as Ca2+ waves traveling across the cell and induced a rapid elevation of nuclear [Ca2+]i. Spontaneous recurrence of smaller-amplitude Ca2+ waves were found in 20% of cells examined after the initial response to RGD-containing peptides. Blocking dihydropyridine-sensitive Ca2+ channels with nifedipine or removal of extracellular Ca2+ did not inhibit the RGD-induced Ca2+mobilization. However, pretreatment of 20 μM ryanodine completely eliminated the RGD-induced Ca2+ mobilization. Anti-β1 and anti-β3-integrin antibodies with functional blocking capability simulate the effects of GRGDSP in [Ca2+]i. Incubation with anti-β1- or β3-integrin antibodies inhibited the increase in [Ca2+]i induced by GRGDSP. We conclude that exogenous RGD-containing peptides induce release of Ca2+ from ryanodine-sensitive Ca2+stores in renal VSMC via integrins, which can trigger cytoplasmic Ca2+ waves propagating throughout the cell.

scholarly journals Differential effects of superoxide and hydrogen peroxide on myogenic signaling, membrane potential, and contractions of mouse renal afferent arterioles

2016 ◽  
Vol 310 (11) ◽  
pp. F1197-F1205 ◽  
Author(s):  
Lingli Li ◽  
En Yin Lai ◽  
Anton Wellstein ◽  
William J. Welch ◽  
Christopher S. Wilcox
Keyword(s):  
Smooth Muscle ◽  
Membrane Potential ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Vascular Smooth Muscle Cells ◽  
Perfusion Pressure ◽  
Principal Component ◽  
Muscle Cells ◽  
Luminal Diameter ◽  
Afferent Arterioles

Myogenic contraction is the principal component of renal autoregulation that protects the kidney from hypertensive barotrauma. Contractions are initiated by a rise in perfusion pressure that signals a reduction in membrane potential ( Em) of vascular smooth muscle cells to activate voltage-operated Ca2+ channels. Since ROS have variable effects on myogenic tone, we investigated the hypothesis that superoxide (O2·−) and H2O2 differentially impact myogenic contractions. The myogenic contractions of mouse isolated and perfused single afferent arterioles were assessed from changes in luminal diameter with increasing perfusion pressure (40–80 mmHg). O2·−, H2O2, and Em were assessed by fluorescence microscopy during incubation with paraquat to increase O2·− or with H2O2. Paraquat enhanced O2·− generation and myogenic contractions (−42 ± 4% vs. −19 ± 4%, P < 0.005) that were blocked by SOD but not by catalase and signaled via PKC. In contrast, H2O2 inhibited the effects of paraquat and reduced myogenic contractions (−10 ± 1% vs. −19 ± 2%, P < 0.005) and signaled via PKG. O2·− activated Ca2+-activated Cl− channels that reduced Em, whereas H2O2 activated Ca2+-activated and voltage-gated K+ channels that increased Em. Blockade of voltage-operated Ca2+ channels prevented the enhanced myogenic contractions with paraquat without preventing the reduction in Em. Myogenic contractions were independent of the endothelium and largely independent of nitric oxide. We conclude that O2·− and H2O2 activate different signaling pathways in vascular smooth muscle cells linked to discreet membrane channels with opposite effects on Em and voltage-operated Ca2+ channels and therefore have opposite effects on myogenic contractions.

Regulation of calcium-activated chloride channels in smooth muscle cells: a complex picture is emerging

2005 ◽  
Vol 83 (7) ◽  
pp. 541-556 ◽  
Author(s):  
Normand Leblanc ◽  
Jonathan Ledoux ◽  
Sohag Saleh ◽  
Amy Sanguinetti ◽  
Jeff Angermann ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Vascular Smooth Muscle Cells ◽  
Chloride Channels ◽  
Muscle Cells ◽  
Cell Types ◽  
Dependent Protein Kinase ◽  
Intracellular Ca ◽  
Dependent Protein

Calcium-activated chloride channels (ClCa) are ligand-gated anion channels as they have been shown to be activated by a rise in intracellular Ca2+ concentration in various cell types including cardiac, skeletal and vascular smooth muscle cells, endothelial and epithelial cells, as well as neurons. Because ClCa channels are normally closed at resting, free intracellular Ca2+ concentration (~100 nmol/L) in most cell types, they have generally been considered excitatory in nature, providing a triggering mechanism during signal transduction for membrane excitability, osmotic balance, transepithelial chloride movements, or fluid secretion. Unfortunately, the genes responsible for encoding this class of ion channels is still unknown. This review centers primarily on recent findings on the properties of these channels in smooth muscle cells. The first section discusses the functional significance and biophysical and pharmacological properties of ClCa channels in smooth muscle cells, and ends with a description of 2 candidate gene families (i.e., CLCA and Bestrophin) that are postulated to encode for these channels in various cell types. The second section provides a summary of recent findings demonstrating the regulation of native ClCa channels in vascular smooth muscle cells by calmodulin-dependent protein kinase II and calcineurin and how their fine tuning by these enzymes may influence vascular tone. Key words: calcium-activated chloride channels, vascular smooth muscle cells, ion channels, calmodulin-dependent protein kinase II, calcineurin

Nucleoplasmic calcium regulation in rabbit aortic vascular smooth muscle cells

2003 ◽  
Vol 81 (3) ◽  
pp. 301-310 ◽  
Author(s):  
Bernard Abrenica ◽  
Grant N Pierce ◽  
James S.C Gilchrist
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Vascular Smooth Muscle Cells ◽  
Signal Intensity ◽  
Laser Scanning ◽  
Muscle Cells ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Intracellular Ca

In this study, we investigated whether nucleoplasmic free Ca2+ in aortic vascular smooth muscle cells (VSMCs) might be independently regulated from cytosolic free Ca2+. Understanding mechanisms and pathways responsible for this regulation is especially relevant given the role of a numerous intranuclear Ca2+-sensitive proteins in transcriptional regulation, apoptosis and cell division. The question of an independent regulatory mechanism remains largely unsettled because the previous use of intensitometric fluorophores (e.g., Fluo-3) has been criticized on technical grounds. To circumvent the potential problem of fluorescence artifact, we utilized confocal laser scanning microscopy to image intracellular Ca2+ movements with the ratiometric fluorophore Indo-1. In cultured rabbit VSMCs, we found sarcoplasmic reticulum (SR) Ca2+ ATPase (SERCA) pumps and ryanodine receptor (RyR) Ca2+ channel proteins to be discretely arranged within a perinuclear locus, as determined by fluorescent staining patterns of BODIPY® FL thapsi gargin and BODIPY® FL-X Ry. When intracellular Ca2+ stores were mobilized by addition of thapsigargin (5 μM) and activatory concentrations of ryanodine (1 μM), Indo-1 ratiometric signals were largely restricted to the nucleoplasm. Cytosolic signals, by comparison, were relatively small and even then its spatial distribution was largely perinuclear rather homogeneous. These observations indicate perinuclear RyR and SERCA proteins are intimately involved in regulating VSMC nucleoplasmic Ca2+ concentrations. We also observed a similar pattern of largely nucleoplasmic Ca2+ mobilization upon exposure of cells to the immunosuppressant drug FK506 (tacrolimus), which binds to the RyR-associated immunophillin-binding proteins FKBP12 and FKBP12.6. However, initial FK506-induced nucleoplasmic Ca2+ mobilization was followed by marked reduction of Indo-1 signal intensity close to pretreatment levels. This suggested FK506 exerts both activatory and inhibitory effects upon RyR channels. The latter was reinforced by observed effects of FK506 to only reduce nucleoplasmic Indo-1 signal intensity when added following pretreatment with both activatory and inhibitory concentrations of ryanodine. These latter observations raise the possibility that VSMC nuclei represent an important sink of intracellular Ca2+ and may help explain vasodilatory actions of FK506 observed by others.Key words: Ca2+, RyR, SERCA, cell nucleus, FK506, thapsigargin, ryanodine.

Neuropeptide Y (NPY) and NPY receptors in the cardiovascular system: implication in the regulation of intracellular calciumThis paper is one of a selection of papers published in this Special Issue, entitled Young Investigators' Forum.

2007 ◽  
Vol 85 (1) ◽  
pp. 43-53 ◽  
Author(s):  
Danielle Jacques ◽  
Dima Abdel-Samad
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Neuropeptide Y ◽  
Vascular Smooth Muscle Cells ◽  
Muscle Cells ◽  
Cell Types ◽  
Heart Cells ◽  
Microscopy Technique ◽  
Intracellular Ca

The 3-dimensional confocal microscopy technique has allowed us to identify the presence of yet another cardioactive factor and its receptor, namely neuropeptide Y (NPY) and its Y1 receptor, at the level of vascular smooth muscle cells and heart cells including endocardial endothelial cells (EECs). Using this technique, we also demonstrated that NPY is able to induce an increase in both cytosolic and nuclear calcium in all these cell types. Furthermore, besides being expressed at the level of EECs, NPY is also released from these cells following a sustained increase of intracellular Ca2+. This suggests the ability of NPY to contribute to the regulation of the excitation–secretion coupling of EECs and the excitation–contraction coupling of cardiomyocytes and vascular smooth muscle cells.

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