Na+/H+ exchange in pulmonary artery smooth muscle from spontaneously hypertensive and Wistar-Kyoto rats

1995 ◽  
Vol 269 (5) ◽  
pp. L673-L680 ◽  
Author(s):  
E. S. Silverman ◽  
B. T. Thompson ◽  
D. A. Quinn ◽  
T. B. Kinane ◽  
J. V. Bonventre ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Pulmonary Artery ◽  
Vascular Remodeling ◽  
Hill Coefficient ◽  
Spontaneously Hypertensive ◽  
Aortic Smooth Muscle ◽  
Wistar Kyoto Rats ◽  
Pulmonary Artery Smooth Muscle ◽  
Wistar Kyoto ◽  
Systemic Arteries

Na+/H+ exchanger regulation of intracellular pH (pHi) may play a key permissive role in the mitogen-induced vascular smooth muscle cell growth that occurs in systemic and pulmonary vascular remodeling. Spontaneously hypertensive rats (SHR) have increased Na+/H+ exchange in systemic vessels as well as greater systemic vascular remodeling compared with normotensive Wistar-Kyoto rats (WKY). In contrast to WKY, SHR demonstrate only mild pulmonary hypertension and no increased remodeling to hypoxia compared with WKY. We therefore wondered whether Na+/H+ exchange in pulmonary artery smooth muscle (PASM) of SHR might not be elevated compared with WKY. Baseline pHi, Vmax, pK0.5, and Hill coefficient were compared in 12- to 14-wk-old SHR and WKY PASM and aortic smooth muscle (AoSM) segments by ratio fluorescence spectroscopy. The Vmax, pK0.5, and Hill coefficient were significantly increased in SHR AoSM segments compared with WKY AoSM segments (53, 0.55, and 53%, respectively; P < 0.05). There were no differences in these values between SHR and WKY PASM segments, unlike the AoSM segments. We conclude that the Na+/H+ exchanger activity in PASM in the SHR is the same as in the WKY, which is in contrast to systemic arteries where Na+/H+ exchange is greater in the SHR.

scholarly journals Long Non-Coding RNA MEG3 Downregulation Triggers Human Pulmonary Artery Smooth Muscle Cell Proliferation and Migration via the p53 Signaling Pathway

2017 ◽  
Vol 42 (6) ◽  
pp. 2569-2581 ◽  
Author(s):  
Zengxian Sun ◽  
Xiaowei Nie ◽  
Shuyang Sun ◽  
Shumin Dong ◽  
Chunluan Yuan ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Smooth Muscle ◽  
Pulmonary Artery ◽  
Smooth Muscle Cells ◽  
Smooth Muscle Cell ◽  
Muscle Cell ◽  
Vascular Remodeling ◽  
Pulmonary Artery Smooth Muscle ◽  
And Migration ◽  
Proliferation And Migration

Background/Aims: Increasing evidence has demonstrated a significant role of long non-coding RNAs (lncRNAs) in diverse biological processes, and many of which are likely to have functional roles in vascular remodeling. However, their functions in pulmonary arterial hypertension (PAH) remain largely unknown. Pulmonary vascular remodeling is an important pathological feature of PAH, leading to increased vascular resistance and reduced compliance. Pulmonary artery smooth muscle cells (PASMCs) dysfunction is involved in vascular remodeling. Long noncoding RNAs are potential regulators of PASMCs function. Herein, we determined whether long noncoding RNA–maternally expressed gene 3 (MEG3) was involved in PAH-related vascular remodeling. Methods: The arterial wall thickness was examined by hematoxylin and eosin (H&E) staining in distal pulmonary arteries (PAs) isolated from lungs of healthy volunteers and PAH patients. The expression level of MEG3 was analyzed by qPCR. The effects of MEG3 on human PASMCs were assessed by cell counting Kit-8 assay, BrdU incorporation assay, flow cytometry, scratch-wound assay, immunofluorescence, and western blotting in human PASMCs. Results: We revealed that the expression of MEG3 was significantly downregulated in lung and PAs of patients with PAH. MEG3 knockdown affected PASMCs proliferation and migration in vitro. Moreover, inhibition of MEG3 regulated the cell cycle progression and made more smooth muscle cells from the G0/G1 phase to the G2/M+S phase and the process could stimulate the expression of PCNA, Cyclin A and Cyclin E. In addition, we found that the p53 pathway was involved in MEG3–induced smooth muscle cell proliferation. Conclusions: This study identified MEG3 as a critical regulator in PAH and demonstrated the potential of gene therapy and drug development for treating PAH.

ID: 123: ROLE OF MICRORNA-1 IN REGULATING PULMONARY VASCULAR REMODELING IN PULMONARY ARTERIAL HYPERTENSION

2016 ◽  
Vol 64 (4) ◽  
pp. 969.1-969 ◽  
Author(s):  
JR Sysol ◽  
J Chen ◽  
S Singla ◽  
V Natarajan ◽  
RF Machado ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Pulmonary Arterial Hypertension ◽  
Pulmonary Artery ◽  
Arterial Hypertension ◽  
Vascular Remodeling ◽  
Luciferase Reporter ◽  
Pulmonary Vascular Remodeling ◽  
Pulmonary Arterial ◽  
Pulmonary Artery Smooth Muscle

RationalePulmonary arterial hypertension (PAH) is a severe, progressive disease characterized by increased pulmonary arterial pressure and resistance due in part to uncontrolled vascular remodeling. The mechanisms contributing to vascular remodeling in PAH are poorly understood and involve rampant pulmonary artery smooth muscle cell (PASMC) proliferation. We recently demonstrated the important role of sphingosine kinase 1 (SphK1), a lipid kinase producing pro-proliferative sphingosine-1-phosphate (S1P), in the development of pulmonary vascular remodeling in PAH. However, the regulatory processes involved in upregulation of SphK1 in this disease are unknown.ObjectiveIn this study, we aimed to identify novel molecular mechanisms governing the regulation of SphK1 expression, with a focus on microRNA (miR). Using both in vitro studies in pulmonary artery smooth muscle cells (PASMCs) and an in vivo mouse model of experimental hypoxia-mediated pulmonary hypertension (HPH), we explored the role of miR in controlling SphK1 expression in the development of pulmonary vascular remodeling.Methods and ResultsIn silico analysis identified hsa-miR-1-3p (miR-1) as a candidate targeting SphK1. We demonstrate miR-1 is down-regulated by hypoxia in human PASMCs and in lung tissues of mice with HPH, coinciding with upregulation of SphK1 expression. PASMCs isolated from patients with PAH had significantly reduced expression of miR-1. Transfection of human PASMCs with miR-1 mimics significantly attenuated activity of a SphK1-3'-UTR luciferase reporter construct and SphK1 protein expression. miR-1 overexpression in human PASMCs also inhibited proliferation and migration under normoxic and hypoxic conditions, both important in pathogenic vascular remodeling in PAH. Finally, we demonstrated that intravenous administration of miR-1 mimics prevents the development of experimental HPH in mice and attenuates induction of SphK1 in PASMCs.ConclusionThese data demonstrate that miR-1 expression in reduced in PASMCs from PAH patients, is modulated by hypoxia, and regulates the expression of SphK1. Key phenotypic aspects of vascular remodeling are influenced by miR-1 and its overexpression can prevent the development of HPH in mice. These studies further our understanding of the mechanisms underlying pathogenic pulmonary vascular remodeling in PAH and could lead to novel therapeutic targets.Supported by grants NIH/NHLBI R01 HL127342 and R01 HL111656 to RFM, NIH/NHLBI P01 HL98050 and R01 HL127342 to VN, American Heart Association Predoctoral Fellowship (15PRE2190004) to JRS, and NIH/NLHBI NRSA F30 Fellowship (FHL128034A) to JRS.

scholarly journals Calpain-2 activates Akt via TGF-β1-mTORC2 pathway in pulmonary artery smooth muscle cells

2016 ◽  
Vol 311 (1) ◽  
pp. C24-C34 ◽  
Author(s):  
Prasanna Abeyrathna ◽  
Laszlo Kovacs ◽  
Weihong Han ◽  
Yunchao Su
Keyword(s):  
Cell Proliferation ◽  
Smooth Muscle ◽  
Growth Factor ◽  
Pulmonary Artery ◽  
Smooth Muscle Cells ◽  
Vascular Remodeling ◽  
Collagen Synthesis ◽  
Pulmonary Vascular Remodeling ◽  
Calpain 2 ◽  
Pulmonary Artery Smooth Muscle

Calpain is a family of calcium-dependent nonlysosomal neutral cysteine endopeptidases. Akt is a serine/threonine kinase that belongs to AGC kinases and plays important roles in cell survival, growth, proliferation, angiogenesis, and cell metabolism. Both calpain and Akt are the downstream signaling molecules of platelet-derived growth factor (PDGF) and mediate PDGF-induced collagen synthesis and proliferation of pulmonary artery smooth muscle cells (PASMCs) in pulmonary vascular remodeling. We found that inhibitions of calpain-2 by using calpain inhibitor MDL28170 and calpain-2 small interfering RNA attenuated Akt phosphorylations at serine-473 (S473) and threonine-308 (T308), as well as collagen synthesis and cell proliferation of PASMCs induced by PDGF. Overexpression of calpain-2 in PASMCs induced dramatic increases in Akt phosphorylations at S473 and T308. Moreover, knockout of calpain attenuated Akt phosphorylations at S473 and T308 in smooth muscle of pulmonary arterioles of mice with chronic hypoxic pulmonary hypertension. The cell-permeable-specific transforming growth factor (TGF)-β receptor inhibitor SB431542 attenuated Akt phosphorylations at both S473 and T308 induced by PDGF and by overexpressed calpain-2 in PASMCs. Furthermore, SB-431452 and knocking down activin receptor-like kinase-5 significantly reduced PDGF-induced collagen synthesis and cell proliferation of PASMCs. Nevertheless, neutralizing extracellular TGF-β1 using a cell-impermeable TGF-β1 neutralizing antibody did not affect PDGF-induced Akt phosphorylations at S473 and T308. Furthermore, inhibition of mammalian target of rapamycin complex 2 (mTORC2) by knocking down its component protein Rictor prevented Akt phosphorylations at S473 and T308 induced by PDGF and by overexpressed calpain-2. These data provide first evidence supporting that calpain-2 upregulates PDGF-induced Akt phosphorylation in pulmonary vascular remodeling via an intracrine TGF-β1/mTORC2 mechanism.

scholarly journals PPARγ regulates hypoxia-induced Nox4 expression in human pulmonary artery smooth muscle cells through NF-κB

2010 ◽  
Vol 299 (4) ◽  
pp. L559-L566 ◽  
Author(s):  
Xianghuai Lu ◽  
Tamara C. Murphy ◽  
Mark S. Nanes ◽  
C. Michael Hart
Keyword(s):  
Pulmonary Hypertension ◽  
Smooth Muscle ◽  
Pulmonary Artery ◽  
Smooth Muscle Cells ◽  
Vascular Remodeling ◽  
Promoter Activity ◽  
Vascular Wall ◽  
Pulmonary Artery Smooth Muscle ◽  
Human Pulmonary Artery ◽  
Stimulation Of

NADPH oxidases are a major source of superoxide production in the vasculature. The constitutively active Nox4 subunit, which is selectively upregulated in the lungs of human subjects and experimental animals with pulmonary hypertension, is highly expressed in vascular wall cells. We demonstrated that rosiglitazone, a synthetic agonist of the peroxisome proliferator-activated receptor-γ (PPARγ), attenuated hypoxia-induced pulmonary hypertension, vascular remodeling, Nox4 induction, and reactive oxygen species generation in the mouse lung. The current study examined the molecular mechanisms involved in PPARγ-regulated, hypoxia-induced Nox4 expression in human pulmonary artery smooth muscle cells (HPASMC). Exposing HPASMC to 1% oxygen for 72 h increased Nox4 gene expression and H2O2 production, both of which were reduced by treatment with rosiglitazone during the last 24 h of hypoxia exposure or by treatment with small interfering RNA (siRNA) to Nox4. Hypoxia also increased HPASMC proliferation as well as the activity of a Nox4 promoter luciferase reporter, and these increases were attenuated by rosiglitazone. Chromatin immunoprecipitation assays demonstrated that hypoxia increased binding of the NF-κB subunit, p65, to the Nox4 promoter and that binding was attenuated by rosiglitazone treatment. The role of NF-κB in Nox4 regulation was further supported by demonstrating that overexpression of p65 stimulated Nox4 promoter activity, whereas siRNA to p50 or p65 attenuated hypoxic stimulation of Nox4 promoter activity. These results provide novel evidence for NF-κB-mediated stimulation of Nox4 expression in HPASMC that can be negatively regulated by PPARγ. These data provide new insights into potential mechanisms by which PPARγ activation inhibits Nox4 upregulation and the proliferation of cells in the pulmonary vascular wall to ameliorate pulmonary hypertension and vascular remodeling in response to hypoxia.

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