Ethylisopropylamiloride-sensitive pH control mechanisms modulate vascular smooth muscle cell growth

1991 ◽  
Vol 260 (3) ◽  
pp. C581-C588 ◽  
Author(s):  
A. Bobik ◽  
A. Grooms ◽  
P. J. Little ◽  
E. J. Cragoe ◽  
S. Grinpukel
Keyword(s):  
Cell Cycle ◽  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Muscle Cells ◽  
Mitotic Cell ◽  
Ph Control ◽  
S Phase ◽  
Control Mechanisms ◽  
Aortic Smooth Muscle ◽  
Exchange Activity

The reported effects of alterations in Na-H exchange activity on mitogenesis are variable and appear dependent on the cell type examined. We examined the effects of reductions in ethylisopropylamiloride (EIPA)-sensitive pH-regulating mechanisms including Na-H exchange and alterations in intracellular pH (pHi) on the growth characteristics of rat aortic smooth muscle cells (RASM) cultured in serum-containing bicarbonate-buffered medium. Exposure of RASM replicating in bicarbonate-containing medium to the Na-H exchange inhibitors EIPA, dimethylamiloride (DMA), or amiloride (A) attenuated their replication rate. The order of potency of the inhibitors (EIPA greater than DMA much greater than A) was similar to their documented effects on Na-H exchange activity and to their order of potency for inhibiting recovery from CO2-induced acidosis in these cells. Reductions in pHi induced by lowering extracellular pH also attenuated the incorporation of [3H]-thymidine into DNA, while increases in pHi were associated with an acceleration in the rate of incorporation of [3H]thymidine into DNA. The effects of the Na-H exchange inhibitors on RASM replication were due to a reduction in the ability of the smooth muscle cells to enter the S phase of the mitotic cell cycle. This appeared predominantly the consequence of effects late within the G1 phase of the cell cycle. Concentrations of EIPA that markedly reduced the ability of RASM to enter S phase and to replicate also attenuated the increase in protein synthesis occurring 6-8 h after exposure to serum.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Transforming growth factor-beta-induced growth inhibition and cellular hypertrophy in cultured vascular smooth muscle cells.

1988 ◽  
Vol 107 (2) ◽  
pp. 771-780 ◽  
Author(s):  
G K Owens ◽  
A A Geisterfer ◽  
Y W Yang ◽  
A Komoriya
Keyword(s):  
Cell Cycle ◽  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Transforming Growth Factor Beta ◽  
Transforming Growth Factor ◽  
Muscle Cells ◽  
Tgf Beta ◽  
Aortic Smooth Muscle Cells ◽  
Aortic Smooth Muscle ◽  
Cellular Hypertrophy

We have explored the hypothesis that hypertrophy of vascular smooth muscle cells may be regulated, in part, by growth inhibitory factors that alter the pattern of the growth response to serum mitogens by characterizing the effects of the potent growth inhibitor, transforming growth factor-beta (TGF-beta), on both hyperplastic and hypertrophic growth of cultured rat aortic smooth muscle cells. TGF-beta inhibited serum-induced proliferation of rat aortic smooth muscle cells (ED50 = 2 pM); this is consistent with previously reported observations in bovine aortic smooth muscle cells (Assoian et al. 1982. J. Biol. Chem. 258:7155-7160). Growth inhibition was due in part to a greater than twofold increase in the cell cycle transit time in cells that continued to proliferate in the presence of TGF-beta. TGF-beta concurrently induced cellular hypertrophy as assessed by flow cytometric analysis of cellular protein content (47% increase) and forward angle light scatter (32-50% increase), an index of cell size. In addition to being time and concentration dependent, this hypertrophy was reversible. Simultaneous flow cytometric evaluation of forward angle light scatter and cellular DNA content demonstrated that TGF-beta-induced hypertrophy was not dependent on withdrawal of cells from the cell cycle nor was it dependent on growth arrest of cells at a particular point in the cell cycle in that both cycling cells in the G2 phase of the cell cycle and those in G1 were hypertrophied with respect to the corresponding cells in vehicle-treated controls. Chronic treatment with TGF-beta (100 pM, 9 d) was associated with accumulation of cells in the G2 phase of the cell cycle in the virtual absence of cells in S phase, whereas subsequent removal of TGF-beta from these cultures was associated with the appearance of a significant fraction of cycling cells with greater than 4c DNA content, consistent with development of tetraploidy. Results of these studies support a role for TGF-beta in the control of smooth muscle cell growth and suggest that at least one mechanism whereby hypertrophy and hyperploidy may occur in this, as well as other cell types, is by alterations in the response to serum mitogens by potent growth inhibitors such as TGF-beta.

scholarly journals A-myb is expressed in bovine vascular smooth muscle cells during the late G1-to-S phase transition and cooperates with c-myc to mediate progression to S phase.

1997 ◽  
Vol 17 (5) ◽  
pp. 2448-2457 ◽  
Author(s):  
D J Marhamati ◽  
R E Bellas ◽  
M Arsura ◽  
K E Kypreos ◽  
G E Sonenshein
Keyword(s):  
Phase Transition ◽  
Cell Cycle ◽  
Smooth Muscle ◽  
Growth Factor ◽  
Smooth Muscle Cells ◽  
Muscle Cells ◽  
S Phase ◽  
Cdna Clones ◽  
Transactivation Domain ◽  
Rna Levels

The Myb family of transcription factors is defined by homology within the DNA binding domain and includes c-Myb, A-Myb, and B-Myb. The protein products of the myb genes all bind the Myb-binding site (MBS) [YG(A/G)C(A/C/G)GTT(G/A)]. A-myb has been found to display a limited pattern of expression. Here we report that bovine aortic smooth muscle cells (SMCs) express A-myb. Sequence analysis of isolated bovine A-myb cDNA clones spanning the entire coding region indicated extensive homology with the human gene, including the putative transactivation domain. Expression of A-myb was cell cycle dependent; levels of A-myb RNA increased in the late G1-to-S phase transition following serum stimulation of serum-deprived quiescent SMC cultures and peaked in S phase. Nuclear run-on analysis revealed that an increased rate of transcription can account for most of the increase in A-myb RNA levels. Treatment of SMC cultures with 5,6-dichlorobenzimidazole riboside, a selective inhibitor of RNA polymerase II, indicated an approximate 4-h half-life for A-myb mRNA during the S phase of the cell cycle. Expression of A-myb by SMCs was stimulated by basic fibroblast growth factor, in a cell density-dependent fashion. Cotransfection of a human A-myb expression vector activated a multimerized MBS element-driven reporter construct approximately 30-fold in SMCs. The activity of c-myb and c-myc promoters, which both contain multiple MBS elements, were similarly transactivated, approximately 30- and 50-fold, respectively, upon cotransfection with human A-myb. Lastly, A-myb RNA levels could be increased by a combination of phorbol ester plus insulin-like growth factor 1. To test the role of myb family members in progression through the cell cycle, we comicroinjected c-myc and myb expression vectors into serum-deprived quiescent SMCs. The combination of c-myc and either A-myb or c-myb but not B-myb synergistically led to entry into S phase, whereas microinjection of any vector alone had little effect on S phase entry. Thus, these results suggest that A-myb is a potent transactivator in bovine SMCs and that its expression induces progression into S phase of the cell cycle.

Effect of pituitary adenylate cyclase activating polypeptide on vasopressin-induced proliferation of aortic smooth muscle cells: comparison with vasoactive intestinal polypeptide

1993 ◽  
Vol 71 (3-4) ◽  
pp. 156-161 ◽  
Author(s):  
Yutaka Oiso ◽  
Jun Kotoyori ◽  
Takashi Murase ◽  
Yoshiaki Ito ◽  
Osamu Kozawa
Keyword(s):  
Cell Cycle ◽  
Smooth Muscle ◽  
Adenylate Cyclase ◽  
Smooth Muscle Cells ◽  
Dna Synthesis ◽  
Vasoactive Intestinal Polypeptide ◽  
Muscle Cells ◽  
Aortic Smooth Muscle Cells ◽  
Aortic Smooth Muscle ◽  
Pituitary Adenylate Cyclase

Pituitary adenylate cyclase activating polypeptide (PACAP) inhibited dose dependently the DNA synthesis stimulated by arginine vasopressin (AVP) in cultured rat aortic smooth muscle cells (SMC). The inhibition was cell cycle dependent and the maximum inhibition was observed when added at the late G1 phase of the cell cycle. Vasoactive intestinal polypeptide (VIP), which shows a considerable homology with PACAP, also inhibited dose dependently the AVP-induced DNA synthesis in a cell cycle dependent manner. The maximum inhibition was also observed at the late G1 phase. The patterns of both the dose-dependent inhibitions were similar, and the inhibition by a combination of PACAP and VIP was not additive. PACAP stimulated dose dependently cAMP accumulation in aortic SMC. VIP also stimulated cAMP accumulation, and the accumulation by a combination of PACAP and VIP was not additive. Both PACAP and VIP had little effect on phosphoinositide hydrolysis in these cells. The suppression of the AVP-induced DNA synthesis by PACAP or VIP was enhanced by 3-isobutyl-1-methylxanthine, an inhibitor for phosphodiesterases. Dibutyryl cAMP, but not 8-bromo-cGMP, inhibited the AVP-induced DNA synthesis, and a combination of PACAP and dibutyryl cAMP was not additive. [Ac-Tyr1, D-Phe2]growth hormone-releasing factor, an antagonist for VIP receptor, reversed the inhibitory effect of PACAP on the AVP-induced DNA synthesis. These results suggest that PACAP has an antiproliferative effect on aortic SMC at the late G1 phase of the cell cycle through cAMP production, and that PACAP and VIP inhibit the AVP-induced DNA synthesis by a common mechanism.Key words: pituitary adenylate cyclase activating polypeptide, vasoactive intestinal polypeptide, arginine vasopressin, DNA synthesis, aortic smooth muscle cells.

Accelerated entry of aortic smooth muscle cells from spontaneously hypertensive rats into the S phase of the cell cycle

1992 ◽  
Vol 70 (7) ◽  
pp. 599-604 ◽  
Author(s):  
Vratislav Hadrava ◽  
Johanne Tremblay ◽  
Rafick-Pierre Sekaly ◽  
Pavel Hamet
Keyword(s):  
Cell Cycle ◽  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Vascular Smooth Muscle Cells ◽  
Spontaneously Hypertensive Rats ◽  
Muscle Cells ◽  
S Phase ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive

The present study was designed to characterize the growth kinetics of the exaggerated proliferative response to mitogens of vascular smooth muscle cells from spontaneously hypertensive rats compared with cells from normotensive Wistar-Kyoto controls. Cellular DNA content, analyzed by flow cytometry, demonstrated a 4-h accelerated entry into the S phase of the cell cycle of vascular smooth muscle cells from spontaneously hypertensive rats; the significant (4.5-fold) increase in the percentage of cells in the S phase occurred between 8 and 12 h after calf serum stimulation. A 3.9-fold increase of cells in the S phase was seen in the normotensive controls only between 12 and 16 h. Transit through the cell cycle was quantitated by flow cytometry using the Hoechst 33 342 – bromodeoxyuridine substitution technique. Vascular smooth muscle cells from spontaneously hypertensive rats went through the cell cycle 4 h ahead of cells from normotensive Wistar-Kyoto rats. This accelerated transit of spontaneously hypertensive rat cells was mostly due to an earlier entry into the S phase. Persistence of this new intermediate phenotype in cell culture suggests its primary pathogenetic role in spontaneous hypertension.Key words: hypertension, proliferation, flow cytometry, bromodeoxyuridine substitution, G0/G, phase.

scholarly journals RGC-32 Increases p34CDC2Kinase Activity and Entry of Aortic Smooth Muscle Cells into S-phase

2001 ◽  
Vol 277 (1) ◽  
pp. 502-508 ◽  
Author(s):  
Tudor Badea ◽  
Florin Niculescu ◽  
Lucian Soane ◽  
Matthew Fosbrink ◽  
Hila Sorana ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Muscle Cells ◽  
S Phase ◽  
Aortic Smooth Muscle Cells ◽  
Aortic Smooth Muscle

scholarly journals Cell cycle-dependent regulation of elastin gene in cultured chick vascular smooth-muscle cells

1995 ◽  
Vol 309 (2) ◽  
pp. 575-579 ◽  
Author(s):  
H Wachi ◽  
Y Seyama ◽  
S Yamashita ◽  
S Tajima
Keyword(s):  
Cell Cycle ◽  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Suspension Culture ◽  
Vascular Smooth Muscle Cells ◽  
Mrna Level ◽  
Muscle Cells ◽  
S Phase ◽  
Elastin Gene

A study was made of the relationship between elastin expression and the proliferative state of chick vascular smooth-muscle cells. Confluent cells of primary culture brought to a quiescent state by the deprivation of serum for 72 h exhibited a 5-, 3.5- and 2-fold increase in elastin synthesis, elastin mRNA level and transcriptional activity of elastin gene respectively over those in the proliferative state. On re-addition of serum in serum-deprived culture, cells started to proliferate, and elastin synthesis, its mRNA level and transcription of the gene decreased to the level of a proliferative state within 24 h, indicating that elastin expression in smooth-muscle cells was controlled by their growth states at least in part at a transcriptional level. A comparable increase in elastin mRNA level was observed when the cell growth was arrested by suspension culture for 72 h. When the cells were synchronized at the G1/S phase with thymidine/hydroxyurea treatment, elastin expression at the G1/S phase was greater than that at the G2/M phase during cell cycling. Elastin mRNA level at the G0 phase brought about by serum-deprivation or suspension culture predominated over that at the G1/S phase during cell cycling. These results indicate that gene expression of elastin and cell cycle are tightly coupled, which is independent of the presence of serum or adhesive state, and that elastin expression could be a biochemical marker for the growth states of smooth-muscle cells.

Sign in / Sign up

Export Citation Format

Share Document