scholarly journals A large accumulation of non-muscle myosin occurs at first entry into M phase in rat vascular smooth-muscle cells

1991 ◽  
Vol 277 (1) ◽  
pp. 145-151 ◽  
Author(s):  
D J Grainger ◽  
T R Hesketh ◽  
J C Metcalfe ◽  
P L Weissberg
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Vascular Smooth Muscle Cells ◽  
Half Life ◽  
Muscle Cells ◽  
S Phase ◽  
Direct Measurements ◽  
M Phase ◽  
Muscle Myosin

Vascular smooth-muscle cells (VSMCs) from rat aortae contained very little non-muscle myosin heavy chain (MHC) immediately after dispersal, and the protein did not accumulate if the cells were held in G0/G1 phase by withholding serum or were held in first S phase by the addition of bromodeoxyuridine (BrdU). However, non-muscle MHC accumulated by greater than 20-fold per cell during first M phase, when over 80% of the cells divided between 48 h and 72 h after addition of serum. Delaying the addition of serum caused a delay in the accumulation of the non-muscle MHC until the cells subsequently entered M phase. If the cells were held in M phase at the metaphase/anaphase boundary by nocadazole, the accumulation of non-muscle myosin still occurred, although division was blocked. When the cells were pulse-labelled with [35S]methionine, it was found that non-muscle MHC was one of the major proteins being made and that its synthesis occurred at similar rates throughout the cell cycle. This implied that the rate of degradation of the protein before first M phase was much faster than in M phase, when the protein accumulated rapidly. This was confirmed by direct measurements of the rate at which [35S]methionine-labelled non-muscle MHC disappeared from the cells, which gave a half-life for the protein of about 8 h before M phase but about 5 days in post-mitotic cells, i.e. an increase of approx. 15-fold. These data are consistent with the hypothesis that there is a mechanism in VSMCs which shortens the half-life of the protein before first M phase and that the accumulation of non-muscle MHC which results from the increase in half-life at first M phase may be necessary for division of these cells.

Radiation suppresses neointimal hyperplasia through affecting proliferation and apoptosis of vascular smooth muscle cells

2018 ◽  
Vol 19 (2) ◽  
pp. 153-161 ◽  
Author(s):  
Liqin Yuan ◽  
Chang Shu ◽  
Xiao Zhou ◽  
Jiehua Li ◽  
Lunchang Wang ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Vascular Smooth Muscle Cells ◽  
Neointimal Hyperplasia ◽  
Muscle Cells ◽  
S Phase ◽  
Nuclear Antigen ◽  
X Ray ◽  
Vsmc Proliferation

Purpose: To study the effect of x-ray radiotherapy on vascular smooth muscle cells (VSMCs) and elucidate the mechanisms in preventing neointimal hyperplasia of prosthetic vascular grafts. Materials and methods: In model I, twelve mongrel dogs underwent revascularization with prosthetic grafts and half the dogs underwent irradiation of the grafts at 28 Gy. In model II, human VSMCs (hVSMCs) were maintained and divided into six groups to which external radiation was applied at six different doses: 0 Gy, 2 Gy, 8 Gy, 16 Gy, 24 Gy and 30 Gy. In both models, specimens were harvested and examined by using morphological, immunological, cellular and molecular methods. Results: After irradiation, the neointima thickness was significantly lower in irradiated groups (p≤0.01). The radiotherapy could up-regulate p27kip1, and down-regulate proliferating cell nuclear antigen (PCNA) and S phase kinase associated protein 2 (Skp2). X-ray irradiation inhibits the proliferation of hVSMCs via acting on G1/S phase of cell cycle. The apoptosis of hVSMCs increased significantly with dose and time. The expression of PCNA and Skp2 were decreased after a first increasing trend with dose, but had a significant negative correlation with time. The expression of p27kip1 had a significant positive correlation with dose and time. Conclusions: Postoperative external fractionated irradiation after prosthetic vessel replacement of the abdominal aorta suppressed the development of hyperplasia in the graft neointima in the short term. There was a prominent time- and dose-dependent inhibition of VSMC proliferation by radiation when it was administered.

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.

Proliferative synergy of ANG II and EGF in porcine aortic vascular smooth muscle cells

1993 ◽  
Vol 265 (2) ◽  
pp. F239-F249
Author(s):  
S. P. Bagby ◽  
E. A. Kirk ◽  
L. H. Mitchell ◽  
M. M. O'Reilly ◽  
W. E. Holden ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Vascular Smooth Muscle Cells ◽  
Muscle Cells ◽  
Cell Number ◽  
S Phase ◽  
Proliferation Rate ◽  
Ang Ii

To test growth effects of angiotensin II (ANG II) in porcine vascular smooth muscle cells (VSMC) and potential ANG II synergy with epidermal growth factor (EGF), we exposed subconfluent, near-quiescent porcine aortic VSMC to ANG II, EGF, or ANG II + EGF (each 10(-9) M) in Dulbecco's modified Eagle's-Ham's F-12 medium with insulin + 0.4% fetal calf serum (FCS) selected for minimal ANG II-degrading capacity. Cell number and DNA and protein synthesis (by [3H]-thymidine and [35S]methionine incorporation, respectively) were determined serially over 1-6 days. ANG II alone induced an early 20% increase and then a plateau in cell number over the 0.4% FCS control (P < 0.01; n = 8), thus without sustained increase in proliferation rate. Yet ANG II alone did not increase fractional DNA or protein synthesis (each as cpm/10(3) cells) and, by flow cytometry, reduced S phase fraction without increase in cell size. EGF alone induced brisk DNA synthesis yet minimal cell division over days 0-4, thus late-cycle arrest. ANG II + EGF, despite no increase in fractional DNA or protein synthesis rates over EGF alone, induced significant indomethacin-resistant dose-dependent (P < 0.001) increase in cell proliferation rate over EGF alone with a median effective dose of 5 x 10(-10) M ANG II, thus proliferative synergy. We propose that 1) ANG II induces a subpopulation of cells arrested in or beyond S phase to proceed through mitosis but does not influence G1 traversal or S phase entry and 2) ANG II + EGF achieve proliferative synergy by complementary actions at sequential cell cycle loci, with EGF supporting progression from G0/G1 to S phase and ANG II inducing completion of mitosis by cells already in or beyond S phase ("late-cycle completion").

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.

Blebbistatin inhibits the chemotaxis of vascular smooth muscle cells by disrupting the myosin II-actin interaction

2008 ◽  
Vol 294 (5) ◽  
pp. H2060-H2068 ◽  
Author(s):  
Hong Hui Wang ◽  
Hideyuki Tanaka ◽  
Xiaoran Qin ◽  
Tiejun Zhao ◽  
Li-Hong Ye ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Vascular Smooth Muscle Cells ◽  
Myosin Ii ◽  
Muscle Cells ◽  
Smooth Muscle Myosin ◽  
A7r5 Cells ◽  
Microscopic Evaluation ◽  
Muscle Myosin

Blebbistatin is a myosin II-specific inhibitor. However, the mechanism and tissue specificity of the drug are not well understood. Blebbistatin blocked the chemotaxis of vascular smooth muscle cells (VSMCs) toward sphingosylphosphorylcholine (IC50 = 26.1 ± 0.2 and 27.5 ± 0.5 μM for GbaSM-4 and A7r5 cells, respectively) and platelet-derived growth factor BB (IC50 = 32.3 ± 0.9 and 31.6 ± 1.3 μM for GbaSM-4 and A7r5 cells, respectively) at similar concentrations. Immunofluorescence and fluorescent resonance energy transfer analysis indicated a blebbistatin-induced disruption of the actin-myosin interaction in VSMCs. Subsequent experiments indicated that blebbistatin inhibited the Mg2+-ATPase activity of the unphosphorylated (IC50 = 12.6 ± 1.6 and 4.3 ± 0.5 μM for gizzard and bovine stomach, respectively) and phosphorylated (IC50 = 15.0 ± 0.6 μM for gizzard) forms of purified smooth muscle myosin II, suggesting a direct effect on myosin II motor activity. It was further observed that the Mg2+-ATPase activities of gizzard myosin II fragments, heavy meromyosin (IC50 = 14.4 ± 1.6 μM) and subfragment 1 (IC50 = 5.5 ± 0.4 μM), were also inhibited by blebbistatin. Assay by in vitro motility indicated that the inhibitory effect of blebbistatin was reversible. Electron-microscopic evaluation showed that blebbistatin induced a distinct conformational change (i.e., swelling) of the myosin II head. The results suggest that the site of blebbistatin action is within the S1 portion of smooth muscle myosin II.

Mechanisms of vasopressin-induced increase in intracellular Na+ in vascular smooth muscle cells

1991 ◽  
Vol 261 (6) ◽  
pp. F1007-F1012 ◽  
Author(s):  
K. Okada ◽  
S. Ishikawa ◽  
T. Saito
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Vascular Smooth Muscle Cells ◽  
Muscle Cells ◽  
Free Calcium ◽  
Dependent Manner ◽  
Free Solution ◽  
Cellular Events ◽  
Direct Measurements

The present study was undertaken to examine the interrelationship between the arginine vasopressin (AVP)-induced dynamic changes in intracellular Ca2+ and Na+ concentrations in cultured rat aortic vascular smooth muscle cells (VSMC) by the direct measurements of intracellular Na+ concentration [( Na+]i), cytosolic free calcium [( Ca2+]i), and intracellular pH (pHi) using fluorescence dyes. AVP increased [Ca2+]i and [Na+]i in a dose-dependent manner; the rise in [Ca2+]i preceded the rise in [Na+]i. Pretreatment with the V1 antagonist [1-(beta-mercapto-beta, beta-cyclopentamethylenepropionic acid) 2-(O-methyl)-tyrosine] AVP [( d(CH2)5Tyr(Me)]AVP) completely blocked the effects of AVP on [Ca2+]i and [Na+]i. The V2 agonist 1-desamino-8-D-AVP, DDAVP, did not affect basal [Na+]i or the AVP-induced increase in [Na+]i. Also, Ca(2+)-free solution completely blocked the AVP-induced increase in [Na+]i. Moreover, Ca(2+)-free solution decreased the AVP-induced intracellular acidification and blunted the later AVP-induced intracellular alkalinization. These results therefore indicate that after binding to the V1 receptor AVP increases [Na+]i mediated by the activation of Na(+)-Ca2+ and Na(+)-H+ exchanges in VSMC. All of these cellular events are completely dependent on an increase in cellular Ca2+ uptake produced by AVP.

Sign in / Sign up

Export Citation Format

Share Document