scholarly journals The mTOR/p70 S6K1 pathway regulates vascular smooth muscle cell differentiation

2004 ◽  
Vol 286 (3) ◽  
pp. C507-C517 ◽  
Author(s):  
Kathleen A. Martin ◽  
Eva M. Rzucidlo ◽  
Bethany L. Merenick ◽  
Diane C. Fingar ◽  
David J. Brown ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Intimal Hyperplasia ◽  
Transcriptional Control ◽  
Matrix Protein ◽  
Kinase Inhibitors ◽  
Extracellular Matrix Protein ◽  
Induced Expression ◽  
Synthetic Phenotype

Vascular smooth muscle cells (VSMC) in mature, normal blood vessels exhibit a differentiated, quiescent, contractile morphology, but injury induces a phenotypic modulation toward a proliferative, dedifferentiated, migratory phenotype with upregulated extracellular matrix protein synthesis (synthetic phenotype), which contributes to intimal hyperplasia. The mTOR (the mammalian target of rapamycin) pathway inhibitor rapamycin inhibits intimal hyperplasia in animal models and in human clinical trials. We report that rapamycin treatment induces differentiation in cultured synthetic phenotype VSMC from multiple species. VSMC treated with rapamycin assumed a contractile morphology, quantitatively reflected by a 67% decrease in cell area. Total protein and collagen synthesis were also inhibited by rapamycin. Rapamycin induced expression of the VSMC differentiation marker contractile proteins smooth muscle (SM) α-actin, calponin, and SM myosin heavy chain (SM-MHC), as observed by immunoblotting and immunohistochemistry. Notably, we detected a striking rapamycin induction of calponin and SM-MHC mRNA, suggesting a role for mTOR in transcriptional control of VSMC gene expression. Rapamycin also induced expression of the cyclin-dependent kinase inhibitors p21cip and p27kip, consistent with cell cycle withdrawal. Rapamycin inhibits mTOR, a signaling protein that regulates protein synthesis effectors, including p70 S6K1. Overexpression of p70 S6K1 inhibited rapamycin-induced contractile protein and p21cip expression, suggesting that this kinase opposes VSMC differentiation. In conclusion, we report that regulation of VSMC differentiation is a novel function of the rapamycin-sensitive mTOR signaling pathway.

scholarly journals Inhibition of Aortic Intimal Hyperplasia and Vascular Smooth Muscle Proliferation and Extracellular Matrix Protein Expressions by Astragalus–Angelica Combination

2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
Huifang Yan ◽  
Xiwei Peng ◽  
Hao Xu ◽  
Jiahuan Zhu ◽  
Changqing Deng
Keyword(s):  
Extracellular Matrix ◽  
Smooth Muscle ◽  
Intimal Hyperplasia ◽  
Matrix Protein ◽  
Vascular Wall ◽  
Extracellular Matrix Protein ◽  
Nuclear Antigen ◽  
Balloon Injury ◽  
Vsmc Proliferation ◽  
Pathway Activation

VSMC proliferation and ECM deposition always resulted in intimal hyperplasia. Astragalus–Angelica combination has a protective effect on the cardiovascular system. The inhibition effect of different Astragalus–Angelica combination on the hyperplastic intima after vascular balloon injury in rats was investigated in this study. Astragalus–Angelica combination can inhibit the intima hyperplasia after balloon injury, in which a 1:1 ratio shows excellent results. Astragalus–Angelica combination can enhance the expression of smooth muscleα-actin (SMа-actin) and inhibit the expression of proliferating cell nuclear antigen (PCNA), cyclin D1, cyclin E, collagen I (Col-I), fibronectin (FN), and matrix metallopeptidase-9 (MMP-9) in hyperplastic intima, suggesting that Astragalus–Angelica combination can inhibit the intimal hyperplasia of blood vessels in rats. The mechanism is related to the inhibition of PI3K/Akt signaling pathway activation and thereby inhibits the phenotypic transformation and cell proliferation of VSMCs and thus inhibits the extracellular matrix (ECM) deposition of vascular wall during intimal hyperplasia.

scholarly journals Glucose downregulation of PKG-I protein mediates increased thrombospondin1-dependent TGF-β activity in vascular smooth muscle cells

2010 ◽  
Vol 298 (5) ◽  
pp. C1188-C1197 ◽  
Author(s):  
Shuxia Wang ◽  
Thomas M. Lincoln ◽  
Joanne E. Murphy-Ullrich
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Protein Expression ◽  
Smooth Muscle Cells ◽  
Vascular Smooth Muscle Cells ◽  
High Glucose ◽  
Matrix Protein ◽  
Muscle Cells ◽  
Extracellular Matrix Protein ◽  
Cardiac Complications

Diabetes is a major predictor of in-stent restenosis, which is associated with fibroproliferative remodeling of the vascular wall due to increased transforming growth factor-β (TGF-β) action. It is well established that thrombospondin1 (TSP1) is a major regulator of TGF-β activation in renal and cardiac complications of diabetes. However, the role of the TSP1-TGF-β pathway in macrovascular diabetic complications, including restenosis, has not been addressed. In mesangial cells, high glucose concentrations depress protein kinase G (PKG) activity, but not PKG-I protein, thereby downregulating transcriptional repression of TSP1. Previously, we showed that high glucose downregulates PKG-I protein expression by vascular smooth muscle cells (VSMCs) through altered NADPH oxidase signaling. In the present study, we investigated whether high glucose regulation of PKG protein and activity in VSMCs similarly regulates TSP1 expression and downstream TGF-β activity. These studies showed that high glucose stimulates both TSP1 expression and TGF-β bioactivity in primary murine aortic smooth muscle cells (VSMCs). TSP1 is responsible for the increased TGF-β bioactivity under high glucose conditions, because treatment with anti-TSP1 antibody, small interfering RNA-TSP1, or an inhibitory peptide blocked glucose-mediated increases in TGF-β activity and extracellular matrix protein (fibronectin) expression. Overexpression of constitutively active PKG, but not the PKG-I protein, inhibited glucose-induced TSP1 expression and TGF-β bioactivity, suggesting that PKG protein expression is insufficient to regulate TSP1 expression. Together, these data establish that glucose-mediated downregulation of PKG levels stimulates TSP1 expression and enhances TGF-β activity and matrix protein expression, which can contribute to vascular remodeling in diabetes.

scholarly journals Vascular smooth muscle cell growth arrest on blockade of thrombospondin-1 requires p21Cip1/WAF1

1999 ◽  
Vol 277 (3) ◽  
pp. H1100-H1106 ◽  
Author(s):  
Donghui Chen ◽  
Kun Guo ◽  
Jihong Yang ◽  
William A. Frazier ◽  
Jeffrey M. Isner ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Matrix Protein ◽  
Molecular Mechanisms ◽  
Cellular Proliferation ◽  
Growth Arrest ◽  
Inhibitory Effect ◽  
Extracellular Matrix Protein ◽  
Inhibitory Protein ◽  
Thrombospondin 1

Abnormal proliferation of vascular smooth muscle cells (VSMCs) is thought to play an important role in the pathogenesis of atherosclerosis and restenosis. Previous studies have implicated the extracellular matrix protein thrombospondin-1 (TSP1) in mitogen-dependent proliferation of VSMCs. In this study, we investigated the molecular mechanisms involved in TSP1-mediated regulation of VSMC growth. Neutralizing A4.1 anti-TSP1 antibody inhibited the activity of the G1/S cyclin-dependent kinase 2 (cdk2) and blocked the induction of S-phase entry, which normally occurs in serum-stimulated VSMCs. This growth-inhibitory effect was associated with a marked induction of p21Cip1/WAF1(p21) expression in A4.1-treated VSMCs. Moreover, addition of A4.1 antibody to VSMCs markedly increased the level of p21 bound to cdk2. Thus growth arrest on antibody blockade of TSP1 may be mediated by the cdk inhibitory protein p21. Consistent with this notion, anti-TSP1 antibody inhibited [3H]-thymidine incorporation in wild-type but not in p21-deficient mouse embryonic fibroblasts (MEFs). Together, these data suggest that p21 plays an important role in TSP1-mediated control of cellular proliferation.

TOXICITY OF SPHERICAL AND NEEDLE-SHAPED CALCIUM PHOSPHATE BIONS TO INJURED INTIMA OF THE RAT ABDOMINAL AORTA

2019 ◽  
pp. 80-88
Author(s):  
А.Г. Кутихин ◽  
Д.К. Шишкова ◽  
Е.А. Великанова ◽  
А.В. Миронов ◽  
Е.О. Кривкина ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Calcium Phosphate ◽  
Systemic Inflammation ◽  
Intravenous Administration ◽  
Intimal Hyperplasia ◽  
Mesenchymal Cells ◽  
Enzyme Linked Immunosorbent Assay ◽  
Cytotoxic Action ◽  
Alizarin Red ◽  
Synthetic Phenotype

Цель исследования - оценка токсического действия сферических кальций-фосфатных бионов и игольчатых кальций-фосфатных бионов на предварительно поврежденную интиму аорты крыс. Методика. Токсическое действие сферических кальций-фосфатных бионов и игольчатых кальций-фосфатных бионов на поврежденную интиму брюшной аорты крыс линии Wistar (n = 10 на группу) оценивали путем их однократного внутривенного введения после баллонной ангиопластики с эксплантацией поврежденного участка аорты через 5 нед. Биоптаты анализировали: 1) классическими гистологическими методами (окрашивание гематоксилин-эозином, ализариновым красным, по Вейгерту-ван Гизону и по Расселлу-Мовату); 2) иммунофлюоресцентным окрашиванием криосрезов (сочетанное окрашивание на CD31 и CD34, на CD31 и α-гладкомышечный актин (α-ГМА), на виментин и α-ГМА, на коллаген IV типа и α-ГМА). Для оценки влияния системного воспаления на КФБ-индуцированную эндотелиотоксичность определяли содержание моноцитарного хемоаттрактантного белка (МСР-1/CCL2) и церулоплазмина в сыворотке крови прооперированных крыс посредством иммуноферментного анализа. Результаты. Сферические кальций-фосфатные бионы и игольчатые кальций-фосфатные бионы вызывали выраженную гипертрофию интимы брюшной аорты в 90% (9 из 10 крыс) и 80% случаев (8 из 10 крыс) соответственно, в то время как частота гипертрофии в группе контрольных крыс составила лишь 10% (1 из 10 крыс). Неоинтима при экспозиции интимы брюшной аорты обоим типам бионов характеризовалась переходом фенотипа клеток мезенхимального ряда с контрактильного (α-ГМА-положительные и виментин-отрицательные гладкомышечные клетки) и неактивного (α-ГМА-отрицательные и виментин-положительные фибробласты) на активный синтетический (α-ГМА- и виментин-положительные клетки), что приводило к формированию значительных количеств экстрацеллюлярного матрикса. Внутривенное введение сферических кальций-фосфатных бионов и игольчатых кальций-фосфатных бионов не приводило к изменению уровней МСР-1/CCL2 и церулоплазмина в сыворотке крови, что свидетельствовало об отсутствии их возможного влияния на развитие системного воспалительного ответа. Заключение. Внутривенное введение кальций-фосфатных бионов после повреждения интимы брюшной аорты крыс путем баллонной ангиопластики вызывает развитие гипертрофии интимы, частота и выраженность которой не зависит от формы кальций-фосфатных бионов и которая характеризуется переходом фенотипа клеток мезенхимального ряда из контрактильного/неактивного на активный синтетический. При этом эндотелиотоксическое действие кальций-фосфатных бионов обусловлено их непосредственным воздействием на эндотелий, а не развитием системного воспаления. Purpose. To compare toxicity of spherical calcium phosphate bions (SCPB) and needle-shaped calcium phosphate bions (NCPB) to injured intima of rat aortas. Methods. Toxicity of SCPB and NCPB to injured abdominal aortas of Wistar rats (n = 10 per group) was evaluated using intravenous administration of the bions after balloon angioplasty. Rats were sacrificed five weeks postoperation, and an injured aortic segment was excised. Tissue preparations were stained with hematoxylin and eosin, alizarin red S, Weigert-van Gieson, and Movat’s pentachrome stains. Selected tissue samples were then examined using combined immunofluorescence staining (CD31/CD34, CD31/α-smooth muscle actin (α-SMA), α-SMA/vimentin, and α-SMA/collagen IV). Possible influence of systemic inflammation on CPB-induced endothelial toxicity was assessed by measuring monocyte chemoattractant protein-1 and ceruloplasmin in rat serum using the enzyme-linked immunosorbent assay. Results. Intravenous administration of SCPB or NCPB provoked intimal hyperplasia in 90% (9 of 10) and 80% (8 of 10) of rats vs. 10% (1 of 10) in the control group. The neointima was characterized by a phenotypic switch of mesenchymal cells, i.e. transition of a contractile (α-SMA-positive, vimentin-negative vascular smooth muscle cells) and quiescent (α-SMA-negative vimentin-positive fibroblasts) to an active synthetic phenotype (double-positive cells), which resulted in deposition of the extracellular matrix. Neither SCPB nor NCPB changed serum levels of pro-inflammatory molecules, МСР-1/CCL2, and ceruloplasmin. Conclusions. Intravenous administration of CPB upon balloon-induced vascular injury caused intimal hyperplasia regardless of the CPB shape. Hyperplasia foci were characterized by a switch of mesenchymal cells from a contractile/quiescent to an active synthetic phenotype. Endothelial toxicity of CPBs was defined by their direct cytotoxic action rather than induction of systemic inflammation.

scholarly journals The role of mitochondrial bioenergetics and reactive oxygen species in coronary collateral growth

2013 ◽  
Vol 305 (9) ◽  
pp. H1275-H1280 ◽  
Author(s):  
Yuh Fen Pung ◽  
Wai Johnn Sam ◽  
James P. Hardwick ◽  
Liya Yin ◽  
Vahagn Ohanyan ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Protein Synthesis ◽  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Energy Production ◽  
Phenotypic Switching ◽  
Oxygen Species ◽  
Coronary Collateral ◽  
Collateral Growth

Coronary collateral growth is a process involving coordination between growth factors expressed in response to ischemia and mechanical forces. Underlying this response is proliferation of vascular smooth muscle and endothelial cells, resulting in an enlargement in the caliber of arterial-arterial anastomoses, i.e., a collateral vessel, sometimes as much as an order of magnitude. An integral element of this cell proliferation is the process known as phenotypic switching in which cells of a particular phenotype, e.g., contractile vascular smooth muscle, must change their phenotype to proliferate. Phenotypic switching requires that protein synthesis occurs and different kinase signaling pathways become activated, necessitating energy to make the switch. Moreover, kinases, using ATP to phosphorylate their targets, have an energy requirement themselves. Mitochondria play a key role in the energy production that enables phenotypic switching, but under conditions where mitochondrial energy production is constrained, e.g., mitochondrial oxidative stress, this switch is impaired. In addition, we discuss the potential importance of uncoupling proteins as modulators of mitochondrial reactive oxygen species production and bioenergetics, as well as the role of AMP kinase as an energy sensor upstream of mammalian target of rapamycin, the master regulator of protein synthesis.

Oxidative Stress Produced with Cell Migration Increases Synthetic Phenotype of Vascular Smooth Muscle Cells

2005 ◽  
Vol 33 (11) ◽  
pp. 1546-1554 ◽  
Author(s):  
Hak-Joon Sung ◽  
Suzanne G. Eskin ◽  
Yumiko Sakurai ◽  
Andrew Yee ◽  
Noriyuki Kataoka ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Smooth Muscle ◽  
Cell Migration ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Vascular Smooth Muscle Cells ◽  
Muscle Cells ◽  
Synthetic Phenotype
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