Upregulation of intermediate-conductance Ca2+-activated K+channel (IKCa1) mediates phenotypic modulation of coronary smooth muscle

2006 ◽  
Vol 291 (5) ◽  
pp. H2493-H2503 ◽  
Author(s):  
D. L. Tharp ◽  
B. R. Wamhoff ◽  
J. R. Turk ◽  
D. K. Bowles
Keyword(s):  
Smooth Muscle ◽  
K Channel ◽  
Marker Genes ◽  
Phenotypic Modulation ◽  
Coronary Smooth Muscle ◽  
Differentiation Marker ◽  
And Migration ◽  
Muscle Myosin ◽  
Early Atherosclerosis

A hallmark of smooth muscle cell (SMC) phenotypic modulation in atherosclerosis and restenosis is suppression of SMC differentiation marker genes, proliferation, and migration. Blockade of intermediate-conductance Ca2+-activated K+channels (IKCa1) has been shown to inhibit restenosis after carotid balloon injury in the rat; however, whether IKCa1 plays a role in SMC phenotypic modulation is unknown. Our objective was to determine the role of IKCa1 channels in regulating coronary SMC phenotypic modulation and migration. In cultured porcine coronary SMCs, platelet-derived growth factor-BB (PDGF-BB) increased TRAM-34 (a specific IKCa1 inhibitor)-sensitive K+current 20-fold; increased IKCa1 promoter histone acetylation and c- jun binding; increased IKCa1 mRNA ∼4-fold; and potently decreased expression of the smooth muscle differentiation marker genes smooth muscle myosin heavy chain (SMMHC), smooth muscle α-actin (SMαA), and smoothelin-B, as well as myocardin. Importantly, TRAM-34 completely blocked PDGF-BB-induced suppression of SMMHC, SMαA, smoothelin-B, and myocardin and inhibited PDGF-BB-stimulated migration by ∼50%. Similar to TRAM-34, knockdown of endogenous IKCa1 with siRNA also prevented the PDGF-BB-induced increase in IKCa1 and decrease in SMMHC mRNA. In coronary arteries from high fat/high cholesterol-fed swine demonstrating signs of early atherosclerosis, IKCa1 expression was 22-fold higher and SMMHC, smoothelin-B, and myocardin expression significantly reduced in proliferating vs. nonproliferating medial cells. Our findings demonstrate that functional upregulation of IKCa1 is required for PDGF-BB-induced coronary SMC phenotypic modulation and migration and support a similar role for IKCa1 in coronary SMC during early coronary atherosclerosis.

Abstract 239: Olfactomedin 2 Regulates Vascular Smooth Muscle Cell Phenotypic Modulation by Mediating the Interaction Between Runx2 and SRF

2015 ◽  
Vol 35 (suppl_1) ◽  
Author(s):  
Ning Shi ◽  
Xiao-Bing Cui ◽  
Shi-You Chen
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cell ◽  
Muscle Cell ◽  
Vascular Smooth Muscle Cell ◽  
Marker Genes ◽  
Important Process ◽  
Phenotypic Modulation ◽  
And Migration ◽  
Proliferation And Migration

Olfactomedin 2 (Olfm2) is a novel regulator for vascular smooth muscle cell (SMC) differentiation, but it is unclear whether Olfm2 is also involved in SMC phenotypic modulation, an important process associated with vascular injury. In this study, we found that Olfm2 was induced during PDGF-BB-induced SMC phenotypic modulation. Olfm2 knockdown attenuated PDGF-BB-induced suppression of SM marker genes including SM myosin heavy chain and SM22α, and also inhibited PDGF-BB-stimulated SMC proliferation and migration. On the other hand, Olfm2 overexpression down-regulated SM markers gene expression, and promoted SMC proliferation marker PCNA expression. Moreover, PDGF-BB slightly induced expression of Runx2, which interfered with the formation of SRF/myocardin ternary complex, but dramatically enhanced SRF-Runx2 interaction, suggesting that certain factors mediate SRF-Runx2 interaction. Indeed, Olfm2 physically interacted with both SRF and Runx2. Blockade of Olfm2 inhibited SRF association with Runx2, leading to increased association between SRF and myocardin, which in turn activated the transcription of SM markers, whereas overexpression of Olfm2 promoted SRF binding to Runx2. These results demonstrated that Olfm2 mediates the interaction between SRF and Runx2, contributing to SMC phenotypic modulation.

scholarly journals Interleukin-1β modulates smooth muscle cell phenotype to a distinct inflammatory state relative to PDGF-DD via NF-κB-dependent mechanisms

2012 ◽  
Vol 44 (7) ◽  
pp. 417-429 ◽  
Author(s):  
Matthew R. Alexander ◽  
Meera Murgai ◽  
Christopher W. Moehle ◽  
Gary K. Owens
Keyword(s):  
Gene Expression ◽  
Smooth Muscle ◽  
Smooth Muscle Cell ◽  
Marker Gene ◽  
Marker Genes ◽  
Atherosclerotic Plaques ◽  
Phenotypic Modulation ◽  
Marker Gene Expression ◽  
Inflammatory State ◽  
Differentiation Marker

Smooth muscle cell (SMC) phenotypic modulation in atherosclerosis and in response to PDGF in vitro involves repression of differentiation marker genes and increases in SMC proliferation, migration, and matrix synthesis. However, SMCs within atherosclerotic plaques can also express a number of proinflammatory genes, and in cultured SMCs the inflammatory cytokine IL-1β represses SMC marker gene expression and induces inflammatory gene expression. Studies herein tested the hypothesis that IL-1β modulates SMC phenotype to a distinct inflammatory state relative to PDGF-DD. Genome-wide gene expression analysis of IL-1β- or PDGF-DD-treated SMCs revealed that although both stimuli repressed SMC differentiation marker gene expression, IL-1β distinctly induced expression of proinflammatory genes, while PDGF-DD primarily induced genes involved in cell proliferation. Promoters of inflammatory genes distinctly induced by IL-1β exhibited over-representation of NF-κB binding sites, and NF-κB inhibition in SMCs reduced IL-1β-induced upregulation of proinflammatory genes as well as repression of SMC differentiation marker genes. Interestingly, PDGF-DD-induced SMC marker gene repression was not NF-κB dependent. Finally, immunofluorescent staining of mouse atherosclerotic lesions revealed the presence of cells positive for the marker of an IL-1β-stimulated inflammatory SMC, chemokine (C-C motif) ligand 20 (CCL20), but not the PDGF-DD-induced gene, regulator of G protein signaling 17 (RGS17). Results demonstrate that IL-1β- but not PDGF-DD-induced phenotypic modulation of SMC is characterized by NF-κB-dependent activation of proinflammatory genes, suggesting the existence of a distinct inflammatory SMC phenotype. In addition, studies provide evidence for the possible utility of CCL20 and RGS17 as markers of inflammatory and proliferative state SMCs within atherosclerotic plaques in vivo.

Abstract 373: Cigarette Smoke Produces Phenotypic Modulation of Cerebral Vascular Smooth Muscle Cells: Role of KLF4 and Epigenetic Control

2012 ◽  
Vol 32 (suppl_1) ◽  
Author(s):  
Muhammad S Ali ◽  
Pascal M Jabbour ◽  
Stavropoula I Tjoumakaris ◽  
L Fernando Gonzalez ◽  
Robert H Rosenwasser ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Cigarette Smoke ◽  
Vascular Smooth Muscle Cells ◽  
Marker Genes ◽  
Phenotypic Modulation ◽  
Histone 3 ◽  
Immune Precipitation ◽  
Differentiation Marker ◽  
Alpha Actin

Objectives: Cigarette smoke is one of the most important environmental factors associated with cerebral aneurysm formation and progression. Cigarette smoke causes phenotypic modulation of Cerebral Vascular Smooth Muscle Cells (VSMCs) which is considered an important underlying mechanism in cerebral aneurysm formation/progression. We studied epigenetic changes caused by Cigarette Smoke Extract (CSE) in VSMC differentiation marker genes. Methods: Rat cerebral VSMCs were treated with CSE at 40 ug/ml (optimal dosage based on preliminary data) dissolved in HEPES buffer (biological activity comparable to soluble components of cigarette smoke in humans) for 2 hours. Cells at 80-90% confluence were fixed with formaldehyde. DNA was sheared using sonication. Chromatin immune-precipitation was performed using following antibodies: 1) anti-KLF4 (Krupple Like Factor 4), 2) anti-HDAC2 (Histone Deacetylase 2), 3) anti-H3K9Ac (Histone 3 Lysine 9 Acetylation), 4) anti-H3K27triMe (Histone 3 Lysine 27 Tri-Methylation) and 5) anti-H4Ac (Histone 4-Acetylation). qPCR was performed with primers specific to CArG containing promoter regions of differentiation marker genes {(alpha-Actin and Myosin Heavy Chain (MHC)} and Myocardin. Results were normalized against input DNA. As part of in vivo experiments Pluronic Gel (40% w/v) containing CSE at 0.8 mg/ml was applied to rat carotid vessels for 6-8 hours. Vessels were harvested and frozen in liquid nitrogen and chromatin immune-precipitation was performed. Results: CSE stimulation promoted a non-differentiated phenotype of cerebral VSMCs. We demonstrated a marked increase in percent enrichment of alpha-actin, MHC and Myocardin promoters with KLF4, HDAC2, and H3K27triMe antibodies and decreased enrichment with H3K9Ac antibody. Although H4Ac antibody showed decreased enrichment at the alpha-Actin promoter, this was not observed for MHC and Myocardin promoters. This was consistent for both in vivo and in vitro studies. Conclusions: We previously demonstrated that CSE decreases expression of cerebral VSMCs marker genes and SRF co-activator, Myocardin and increases expression of transcription factor, KLF4. Further it promotes a pro-inflammatory phenotype. Decreased expression of the above mentioned genes is a result of direct binding of KLF4 to the CArG containing promoter region. Further, KLF4 recruits HDAC2 which deacetylases H3K9 and H4 causing DNA compaction thereby repressing transcription. Our results provide insight into the underlying molecular mechanisms involved in CSE-induced VSMC phenotypic modulation and provide future potential therapeutic targets applicable to cerebral aneurysms.

scholarly journals Jagged1/Notch3 Signaling Modulates Hemangioma-Derived Pericyte Proliferation and Maturation

2016 ◽  
Vol 40 (5) ◽  
pp. 895-907 ◽  
Author(s):  
Yi Ji ◽  
Siyuan Chen ◽  
Bo Xiang ◽  
Yuan Li ◽  
Li Li ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Smooth Muscle ◽  
Smooth Muscle Actin ◽  
Growth Arrest ◽  
Notch Signaling Pathway ◽  
Cell Growth Arrest ◽  
Muscle Myosin ◽  
Dependent Mechanism

Background: The Notch signaling pathway has been implicated in the pericyte phenotype, but its exact roles in hemangioma-derived pericytes (Hem-pericytes) remain ill defined. Methods: Hem-pericytes were stimulated by immobilized recombinant Jagged1. The potential mechanisms of Notch-induced Hem-pericytes growth arrest were investigated by cell cycle assay, and the role of the Notch in promoting Hem-pericyte maturation was also analyzed by real-time PCR and western blot. Results: Activation of Notch3 in Hem-pericytes significantly reduced cell proliferation and inhibited cell cycle transition. This event was associated with an increase in the levels of p21Cip1. Knockdown of p21Cip1 resulted in a significant rescue of Notch-induced cell growth arrest and an entry into the cell cycle. We showed that Jagged1 activation of Notch3 signaling upregulated the expression of the pericyte contractile markers smooth muscle myosin heavy chain (smMHC) and α-smooth muscle actin (αSMA), concomitant with an increase in the expression of myocardin in Hem-pericytes. We further revealed that the endothelial-derived Jagged1 modulated the Hem-pericyte phenotype via a contact-dependent mechanism. Conclusions: Our results demonstrated that Jagged1 activation of Notch3 resulted in a significant decrease in cell proliferation while concomitantly promoting Hem-pericyte maturation. These data provide initial evidence that Notch induces a quiescent phenotype in Hem-pericytes.

scholarly journals PDGFBB promotes proliferation and migration via regulating miR-1181/STAT3 axis in human pulmonary arterial smooth muscle cells

2018 ◽  
Vol 315 (6) ◽  
pp. L965-L976 ◽  
Author(s):  
Zhengjiang Qian ◽  
Yanjiao Li ◽  
Haiyang Yang ◽  
Jidong Chen ◽  
Xiang Li ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Muscle Cells ◽  
Causative Factor ◽  
Loss Of Function ◽  
Migration Flow ◽  
Pulmonary Arterial ◽  
And Migration ◽  
Proliferation And Migration

Platelet-derived growth factor (PDGF) can induce hyperproliferation of pulmonary artery smooth muscle cells (PASMCs), which is a key causative factor to the occurrence and progression of pulmonary arterial hypertension (PAH). We previously identified that miR-1181 is significantly downregulated by PDGFBB in human PASMCs. In this work, we further explore the function of miR-1181 and underlying regulatory mechanisms in PDGF-induced PASMCs. First, the expression pattern of miR-1181 was characterized under PDGFBB treatment, and PDGF receptor/PKCβ signaling was found to repress miR-1181 expression. Then, gain- and loss-of-function experiments were respectively conducted and revealed the prominent role of miR-1181 in inhibiting PASMC proliferation and migration. Flow cytometry analysis suggested that miR-1181 regulated the PASMC proliferation through influencing the cell cycle transition from G0/G1 to S phase. Moreover, we exhibited that miR-1181 targeting STAT3 formed a regulatory axis to modulate PASMC proliferation. Finally, serum miR-1181 expression was also observed to be reduced in adult and newborn patients with PAH. Overall, this study provides novel findings that the miR-1181/STAT3 axis mediated PDGFBB-induced dysfunction in human PASMCs, implying a potential use of miR-1181 as a therapeutic and diagnostic candidate for the vascular remodeling diseases.

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