Hypotonic swelling-induced Ca2+ release by an IP3-insensitive Ca2+ store

2001 ◽  
Vol 281 (2) ◽  
pp. C555-C562 ◽  
Author(s):  
Madhumita Jena Mohanty ◽  
Maian Ye ◽  
Xingli Li ◽  
Noreen F. Rossi
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Nicotinic Acid ◽  
Vascular Smooth Muscle Cells ◽  
Ruthenium Red ◽  
A7r5 Cells ◽  
Inositol 1,4,5 Trisphosphate ◽  
Intracellular Ca ◽  
Hypotonic Swelling

Hypotonic swelling increases the intracellular Ca2+ concentration ([Ca2+]i) in vascular smooth muscle cells (VSMC). The source of this Ca2+ is not clear. To study the source of increase in [Ca2+]i in response to hypotonic swelling, we measured [Ca2+]i in fura 2-loaded cultured VSMC (A7r5 cells). Hypotonic swelling produced a 40.7-nM increase in [Ca2+]i that was not inhibited by EGTA but was inhibited by 1 μM thapsigargin. Prior depletion of inositol 1,4,5-trisphosphate (IP3)-sensitive Ca2+ stores with vasopressin did not inhibit the increase in [Ca2+]i in response to hypotonic swelling. Exposure of 45Ca2+-loaded intracellular stores to hypotonic swelling in permeabilized VSMC produced an increase in45Ca2+ efflux, which was inhibited by 1 μM thapsigargin but not by 50 μg/ml heparin, 50 μM ruthenium red, or 25 μM thio-NADP. Thus hypotonic swelling of VSMC causes a release of Ca2+ from the intracellular stores from a novel site distinct from the IP3-, ryanodine-, and nicotinic acid adenine dinucleotide phosphate-sensitive stores.

Stretch-induced Ca2+ release via an IP3-insensitive Ca2+ channel

2002 ◽  
Vol 283 (2) ◽  
pp. C456-C462 ◽  
Author(s):  
Madhumita Jena Mohanty ◽  
Xingli Li
Keyword(s):  
Smooth Muscle ◽  
Nicotinic Acid ◽  
Vascular Smooth Muscle Cells ◽  
Mechanical Stimulation ◽  
Ruthenium Red ◽  
Cytochalasin D ◽  
Mechanical Stimuli ◽  
Inositol 1,4,5 Trisphosphate ◽  
Intracellular Ca ◽  
Cyclical Stretch

Various mechanical stimuli increase the intracellular Ca2+ concentration ([Ca2+]i) in vascular smooth muscle cells (VSMC). A part of the increase in [Ca2+]i is due to the release of Ca2+ from intracellular stores. We have investigated the effect of mechanical stimulation produced by cyclical stretch on the release of Ca2+ from the intracellular stores. Permeabilized VSMC loaded with45Ca2+ were subjected to 7.5% average (15% maximal) cyclical stretch. This resulted in an increase in45Ca2+ rate constant by 0.126 ± 0.0035. Inhibition of inositol 1,4,5-trisphosphate (IP3), ryanodine, and nicotinic acid adenine dinucleotide phosphate channels (NAADP) with 50 μg/ml heparin, 50 μM ruthenium red, and 25 μM thio-NADP, respectively, did not block the increase in45Ca2+ efflux in response to cyclical stretch. However, 10 μM lanthanum, 10 μM gadolinium, and 10 μM cytochalasin D but not 10 μM nocodazole inhibited the increase in45Ca2+ efflux. This supports the existence of a novel stretch-sensitive intracellular Ca2+ store in VSMC that is distinct from the IP3-, ryanodine-, and NAADP-sensitive stores.

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.

Seaweed Porphyra yezoensis polysaccharides with different molecular weights inhibit hydroxyapatite damage and osteoblast differentiation of A7R5 cells

2020 ◽  
Vol 11 (4) ◽  
pp. 3393-3409
Author(s):  
Ling-Hong Huang ◽  
Hong Liu ◽  
Jia-Yun Chen ◽  
Xin-Yuan Sun ◽  
Zhi-hui Yao ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Vascular Smooth Muscle Cells ◽  
Osteoblast Differentiation ◽  
Cell Damage ◽  
Porphyra Yezoensis ◽  
Molecular Weights ◽  
A7r5 Cells ◽  
Hydroxyapatite Crystals

Porphyra yezoensis polysaccharide could effectively reduce the cell damage and osteogenic transformation of vascular smooth muscle cells induced by hydroxyapatite crystals.

Sphingolipids as mediators of effects of platelet-derived growth factor in vascular smooth muscle cells

1993 ◽  
Vol 265 (3) ◽  
pp. C740-C747 ◽  
Author(s):  
L. S. Jacobs ◽  
M. Kester
Keyword(s):  
Smooth Muscle ◽  
Growth Factor ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Dna Synthesis ◽  
Vascular Smooth Muscle Cells ◽  
Platelet Derived Growth Factor ◽  
Sphingolipid Metabolism ◽  
A7r5 Cell ◽  
A7r5 Cells

The role of sphingolipids in mediating the action of platelet-derived growth factor (PDGF) has been investigated in the vascular smooth muscle-derived A7r5 cell line. L-Cycloserine (2 mM), an inhibitor of sphingolipid synthesis, caused time-dependent inhibition of [3H]serine incorporation into [3H]sphingomyelin in A7r5 cells. PDGF-AB (10 ng/ml), PDGF-BB (10 ng/ml), or sphingosine (10 microM) independently stimulated [3H]thymidine incorporation into DNA in A7r5 cells. L-Cycloserine (2 mM) inhibited stimulation of DNA synthesis by both PDGF-AB and PDGF-BB. L-Cycloserine (2 mM, 16 h) did not affect the ability of PDGF or sphingosine to increase intracellular free calcium ([Ca2+]i) in A7r5 cells loaded with the fluorescent indicator fura 2. Measurement of adenine nucleotide levels in A7r5 cell extracts by reverse-phase high-performance liquid chromatography indicated that treatment with L-cycloserine did not adversely affect cellular metabolism. To determine directly whether PDGF activates sphingolipid metabolism, A7r5 cells were labeled with [3H]serine for 48 h and then treated with PDGF-AB (10 ng/ml) for 1 h. Sphingolipids were separated by thin-layer chromatography and quantified by liquid scintillation counting. PDGF-AB stimulated an increase in [3H]sphingosine from 25.5 +/- 3.0 to 37.5 +/- 4.1 counts.min-1 (cpm).micrograms protein-1 and a concomitant decrease in [3H]ceramide from 24.3 +/- 3.2 to 18.5 +/- 2.9 cpm/micrograms protein. These data suggest that the PDGF-stimulated increase in [Ca2+]i is not sufficient for induction of DNA synthesis and that mitogenic effects of PDGF in vascular smooth muscle cells are mediated by sphingolipid metabolism.

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+.

Thapsigargin stimulates Ca2+ entry in vascular smooth muscle cells: nicardipine-sensitive and -insensitive pathways

1992 ◽  
Vol 262 (5) ◽  
pp. C1258-C1265 ◽  
Author(s):  
Y. T. Xuan ◽  
O. L. Wang ◽  
A. R. Whorton
Keyword(s):  
Smooth Muscle ◽  
Sarcoplasmic Reticulum ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Vascular Smooth Muscle Cells ◽  
Muscle Cells ◽  
Inositol Polyphosphate ◽  
Inositol Polyphosphates ◽  
Permeabilized Cells ◽  
Inositol 1,4,5 Trisphosphate

We have investigated the role of the sarcoplasmic reticulum Ca2+ pool in regulating Ca2+ entry in vascular smooth muscle cells using a receptor-independent means of mobilizing the intracellular Ca2+ pool. Thapsigargin (TG) has been shown to inhibit the endoplasmic reticulum Ca(2+)-ATPase, mobilize intracellular Ca2+, and activate Ca2+ entry in nonmuscle tissues. When smooth muscle cells were treated with 0.2 microM TG, cytosolic Ca2+ concentrations rose gradually over 8 min to a peak value of 365 +/- 18 nM. Cytosolic Ca2+ remained elevated for at least 20 min and was supported by continued entry of extracellular Ca2+. TG also stimulated entry of Mn2+ and 45Ca2+ from outside the cell. Importantly, TG-induced Ca2+ entry and Mn2+ entry were found to occur through mechanisms that were independent of L-type Ca2+ channel activation because influx was not inhibited by concentrations of nicardipine that were found to block either endothelin- or 100 mM extracellular K(+)-induced cation influx. The mechanism through which TG activates cation entry appears to involve mobilization of the inositol 1,4,5-trisphosphate-responsive intracellular Ca2+ pool. In permeabilized cells, TG prevented ATP-stimulated Ca2+ uptake into the sarcoplasmic reticulum and slowly released sequestered Ca2+. The Ca2+ pool involved was responsive to inositol 1,4,5-trisphosphate. However, TG did not initiate the formation of inositol polyphosphates. Thus TG mobilizes the sarcoplasmic reticulum Ca2+ pool and activates Ca2+ entry through a nicardipine-insensitive Ca2+ channel in vascular smooth muscle. The mechanism is independent of inositol polyphosphate formation.

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 Adenylyl cyclase isoforms and signal integration in models of vascular smooth muscle cells

2001 ◽  
Vol 281 (4) ◽  
pp. H1545-H1552 ◽  
Author(s):  
Jerry G. Webb ◽  
Phillip W. Yates ◽  
Qing Yang ◽  
Yurii V. Mukhin ◽  
Stephen M. Lanier
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Adenylyl Cyclase ◽  
Cell Line ◽  
Vascular Smooth Muscle Cells ◽  
Muscle Cells ◽  
Ionophore A23187 ◽  
Signal Integration ◽  
A7r5 Cells

Adenylyl cyclases present a potential focal point for signal integration in vascular smooth muscle cells (VSMC) influencing contractile state and cellular responses to vessel wall injury. In the present study, we examined the influence of the vasoactive peptide arginine vasopressin (AVP) on cAMP regulation in primary cultures of rat aortic VSMC and in the A7r5 arterial smooth muscle cell line. In cultured VSMC and A7r5 cells, AVP had no effect on basal cAMP but differentially affected β-adrenergic receptor-induced activation of adenylyl cyclase. AVP synergistically increased (twofold) isoproterenol-stimulated cAMP production in VSMC but inhibited the effect of isoproterenol (50%) in the A7r5 cell line. The effects of AVP in both preparations were blocked when cells were pretreated with a selective V1vasopressin receptor antagonist. Moreover, the actions of AVP in both models were dependent on release of intracellular Ca2+ and were mimicked by elevation of Ca2+ with the ionophore A23187 , suggesting that the responses to AVP involve Ca2+-mediated regulation of adenylyl cyclase stimulation. Adenylyl cyclase types I, III, and VIII are stimulated by Ca2+/calmodulin, whereas types V and VI are directly inhibited by Ca2+. RNA blot analysis for effector isotypes indicated that both VSMC and A7r5 cells expressed types III, V, and VI. VSMC also expressed mRNA for type IV and VIII effectors, which could account for the cell-specific responses to peptide hormone and Ca2+.

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