scholarly journals An EPAC1/PDE1C-Signaling Axis Regulates Formation of Leading-Edge Protrusion in Polarized Human Arterial Vascular Smooth Muscle Cells

Cells ◽  
2019 ◽  
Vol 8 (12) ◽  
pp. 1473 ◽  
Author(s):  
Paulina Brzezinska ◽  
Donald H. Maurice

Pharmacological activation of protein kinase A (PKA) reduces migration of arterial smooth muscle cells (ASMCs), including those isolated from human arteries (HASMCs). However, when individual migration-associated cellular events, including the polarization of cells in the direction of movement or rearrangements of the actin cytoskeleton, are studied in isolation, these individual events can be either promoted or inhibited in response to PKA activation. While pharmacological inhibition or deficiency of exchange protein activated by cAMP-1 (EPAC1) reduces the overall migration of ASMCs, the impact of EPAC1 inhibition or deficiency, or of its activation, on individual migration-related events has not been investigated. Herein, we report that EPAC1 facilitates the formation of leading-edge protrusions (LEPs) in HASMCs, a critical early event in the cell polarization that underpins their migration. Thus, RNAi-mediated silencing, or the selective pharmacological inhibition, of EPAC1 decreased the formation of LEPs by these cells. Furthermore, we show that the ability of EPAC1 to promote LEP formation by migrating HASMCs is regulated by a phosphodiesterase 1C (PDE1C)-regulated “pool” of intracellular HASMC cAMP but not by those regulated by the more abundant PDE3 or PDE4 activities. Overall, our data are consistent with a role for EPAC1 in regulating the formation of LEPs by polarized HASMCs and show that PDE1C-mediated cAMP hydrolysis controls this localized event.

Hypertension ◽  
2013 ◽  
Vol 62 (suppl_1) ◽  
Author(s):  
Marcela Herrera ◽  
Matthew A Sparks ◽  
Beverky H Koller ◽  
Thomas M Coffman

Prostaglandin E2 (PGE2) is a major prostanoid produced by the kidney having the potential to influence renal blood flow, Na excretion, and thus mean arterial pressure (BP). PGE2 actions are mediated by four distinct E-prostanoid (EP) receptor isoforms: EP1-EP4. The EP4 receptor (EP4R) triggers macula densa stimulation of renin, induces vasodilation, and may inhibit epithelial sodium transport. Thus, the impact of EP4Rs on BP may differ with the sites of PGE2 synthesis and pattern of EP4R activation within the kidney. To examine the role of EP4R on BP regulation we generated EP4R-deficient mice. Because deletion of EP4R in utero causes peri-natal mortality due to persistent patent ductus arteriosus, we carried out conditional deletion by crossing EP4flox/flox with a transgenic line with tamoxifen-inducible Cre expression in all tissues. Resting mean arterial pressure (MAP) measured by radiotelemetry was increased by 5±1mm Hg (p<0.05) in mice with total-body EP4R-deficiency (EP4R-TBKO) vs. controls. In addition, EP4R-TBKOs had an exaggerated increase in MAP with high-salt (6% NaCl) feeding (MAP increase: 5±1 vs. 2±1mmHg for controls; p<0.05) and during angiotensin II (Ang II)-dependent hypertension (MAP increase: 37±2 vs. 24±3mmHg for controls; p<0.05). We next hypothesized that exaggerated hypertension in the EP4R-TBKOs was due to elimination of compensatory EP4R-depedent vasodilation mediated by direct actions in vascular smooth muscle cells (VSMCs). Accordingly, we generated mice lacking EP4R in VSMCs (EP4R-SMKOs) using EP4flox/flox and transgenic mice with tamoxifen-inducible expression of Cre limited to smooth muscle cells. In contrast to the EP4R-TBKOs, elimination of EP4R only from VSMC reduced resting MAP by 5±1mm Hg (p<0.04) but did not affect the BP response to high salt feeding (MAP change: 2±1 vs. 2±1 mm Hg; ns) or chronic Ang II infusion (MAP increase: 29±3 vs. 34±4 mm Hg; ns). Thus, the EP4R modulates resting MAP but its specific impact may vary between EP4R populations in different cell lineages. EP4Rs resist the development of salt- and Ang II-dependent hypertension. These anti-hypertensive actions are not mediated by direct effects of EP4R in VSMCs, but may involve EP4R in endothelium, brain, or kidney epithelia.


2007 ◽  
Vol 292 (5) ◽  
pp. L1202-L1210 ◽  
Author(s):  
Shen Zhang ◽  
Hemal H. Patel ◽  
Fiona Murray ◽  
Carmelle V. Remillard ◽  
Christian Schach ◽  
...  

Pulmonary vascular remodeling due to overgrowth of pulmonary artery smooth muscle cells (PASMC) is a major cause for the elevated vascular resistance in patients with idiopathic pulmonary arterial hypertension (IPAH). Increased cytosolic Ca2+ concentration, resulting from enhanced capacitative Ca2+ entry (CCE) and upregulated transient receptor potential (TRP) channel expression, is involved in stimulating PASMC proliferation. The current study was designed to determine the impact of cAMP, a second messenger that we hypothesized would blunt aspects of PASMC activity, as a possible contributor to IPAH pathophysiology. Short-term (30 min) pretreatment with forskolin (FSK; 10 μM), a direct activator of adenylyl cyclase, in combination with the cyclic nucleotide phosphodiesterase inhibitor isobutylmethylxanthine (IBMX; 200 μM), attenuated CCE in PASMC from normal subjects, patients without pulmonary hypertension (NPH), and patients with IPAH. The FSK-mediated CCE inhibition was independent of protein kinase A (PKA), because the PKA inhibitor H89 negligibly affected the decrease in CCE produced by cAMP. By contrast, longer (4 h) treatment with FSK (with IBMX) attenuated CCE in normal and NPH PASMC but enhanced CCE in IPAH PASMC. This enhancement of CCE was abolished by PKA inhibition and associated with an upregulation of TRPC3. In addition, cAMP increased TRPC1 mRNA expression in IPAH (but not in normal or NPH) PASMC, an effect blunted by H89. Furthermore, iloprost, a prostacyclin analog that increases cAMP, downregulated TRPC3 expression in IPAH PASMC and FSK-mediated cAMP increase inhibited IPAH PASMC proliferation. Although a rapid rise in cellular cAMP decreases CCE by a PKA-independent mechanism, sustained cAMP increase inhibits CCE in normal and NPH PASMC but increases CCE via a PKA-dependent pathway in IPAH PASMC. The divergent effect of cAMP on CCE parallels effects on TRPC expression. The results suggest that the combined use of a PKA inhibitor and cAMP-elevating drugs may provide a novel approach for treatment of IPAH.


2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Katarzyna Szadujkis-Szadurska ◽  
Bartosz Malinowski ◽  
Małgorzata Piotrowska ◽  
Grzegorz Grześk ◽  
Michał Wiciński ◽  
...  

Aim of the Study.The purpose of this study was to investigate the impact of ischemia and reperfusion on the resistance of arteries to AVP (arginine vasopressin), with a particular emphasis on the role of smooth muscle cells in the action of vasopressin receptors and the role of the cGMP-associated signalling pathway.Materials and Methods.Experiment was performed on the perfunded tail arteries from male Wistar rats. The constriction triggered by AVP after 30 minutes of ischemia and 30 and 90 minutes of reperfusion was analysed. Analogous experiments were also carried out in the presence of 8Br-cGMP.Results.Ischemia reduces and reperfusion increases in a time-dependent manner the arterial reaction to AVP. The presence of 8Br-cGMP causes a significant decrease of arterial reactivity under study conditions.Conclusions.Ischemia and reperfusion modulate arterial contraction triggered by AVP. The effect of 8Br-cGMP on reactions, induced by AVP after ischemia and reperfusion, indicates that signalling pathway associated with nitric oxide (NO) and cGMP regulates the tension of the vascular smooth muscle cells.


Author(s):  
Taby Ahsan ◽  
Adele M. Doyle ◽  
Garry P. Duffy ◽  
Frank Barry ◽  
Robert M. Nerem

Vascular applications in regenerative medicine include blood vessel substitutes and vasculogenesis in ischemic or engineered tissues. For these repair processes to be successful, there is a need for a stable supply of endothelial and smooth muscle cells. For blood vessel substitutes, the immediate goal is to enable blood flow, but vasoactivity is necessary for long term success. In engineered vessels, it is thought that endothelial cells will serve as an anti-thrombogenic lumenal layer, while smooth muscle cells contribute to vessel contractility. In other clinical applications, what is needed is not a vessel substitute but the promotion of new vessel formation (vasculogenesis). A simplified account of vasculogenesis is that endothelial cells assemble to form vessel-like structures that can then be stabilized by smooth muscle cells. Overall, the need for new vasculature to transfer oxygen and nutrients is important to reperfuse not only ischemic tissue in vivo, but also dense, structurally complex engineered tissue. The impact of these vascular therapies, however, is limited in part by the low yield and inadequate in vitro proliferation potential of primary endothelial and smooth muscle cells. Thus, there is a need to address the cell sourcing issue for vascular cell-based therapies, potentially using stem cells.


2000 ◽  
Vol 113 (4) ◽  
pp. 653-662 ◽  
Author(s):  
A. Scherberich ◽  
M. Campos-Toimil ◽  
P. Ronde ◽  
K. Takeda ◽  
A. Beretz

Migration of vascular smooth muscle cells (VSMC) is a key event in the formation of neointima during atherosclerosis. Fura-2 loaded VSMCs were used to investigate calcium homeostasis during cell migration. Multiple spontaneous transient increases in cytosolic free calcium [Ca(2+)](i)were observed in single human VSMCs migrating on type I collagen. Such [Ca(2+)](i)transients were dependent on the presence of serum or PDGF-BB. Removal of serum, or loading cells with BAPTA, abolished the transients and decreased cell migration speed. The transients were not affected by disruption of cell polarization by dihydrocytochalasin B. Adhesion was used to investigate the specific role of cell-substrate interactions in the generation of transients. Transients are seen in VSMCs adhering either on collagen or on poly-L-lysine, suggesting that generation of transients is not strictly dependent on integrins. Buffering [Ca(2+)](i) with BAPTA led to accumulation of (beta)1 integrins at the cellular tail, and to increased release of integrin on the extracellular matrix. These results demonstrate a role for [Ca(2+)](i) transients in the rapid, serum-dependent migration of VSMCs. These [Ca(2+)](i)transients are present in migrating VSMCs only when two simultaneous events occur: (1) substrate independent spreading and (2) stimulation of cells by serum components such as PDGF-BB.


2014 ◽  
Vol 10 (2) ◽  
pp. 688-700 ◽  
Author(s):  
Raila Busch ◽  
Anne Strohbach ◽  
Stefanie Rethfeldt ◽  
Simon Walz ◽  
Mathias Busch ◽  
...  

2004 ◽  
Vol 286 (5) ◽  
pp. H1985-H1993 ◽  
Author(s):  
Chunlin Wang ◽  
Chunhua Jiao ◽  
Heather D. Hanlon ◽  
Wei Zheng ◽  
Robert J. Tomanek ◽  
...  

It appears that there are two classes of human circulating endothelial cell (EC) progenitors, CD34+and CD34–CD14+cells. Attention has focused on CD34+cells, yet CD34–CD14+monocytic cells are far more abundant and may represent the most common class of circulating EC progenitor. Little is known about molecular or physiological factors that regulate putative CD34–CD14+EC progenitor function, although factors secreted by other blood and cardiovascular cells to which they are exposed probably affect their behavior. Hypoxia and stretch are two important physiological stimuli known to trigger growth factors in cardiovascular cells and accordingly may modulate EC progenitors. To investigate the impact of these environmental parameters on EC progenitors, EC production in CD34–CD14+cultures was evaluated. Our data indicate that neither stretch nor hypoxia alters EC production by EC progenitors directly but do so indirectly through their effects on cardiovascular cells. Conditioned media (CM) from coronary artery smooth muscle cells inhibit EC production in culture, and this inhibition is stronger if the coronary smooth muscle cells have been subjected to cyclic stretch. In contrast, cardiomyocyte CM increases EC cell number, an effect that is potentiated if the myocytes have been subjected to hypoxia. Significantly, EC progenitor responses to CM are altered by the presence of CD34–CD14–peripheral blood mononuclear cells (PBMCs). Moreover, CD34–CD14–PBMCs attenuate EC progenitor responsiveness to the angiogenic factors basic fibroblast growth factor (FGF-2), vascular endothelial cell growth factor-A165, and erythropoietin while inducing EC progenitor death in the presence of transforming growth factor-β1in vitro


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