scholarly journals Novel Pannexin-1-Coupled Signaling Cascade Involved in the Control of Endothelial Cell Function and NO-Dependent Relaxation

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Mauricio A. Lillo ◽  
Pablo S. Gaete ◽  
Mariela Puebla ◽  
Pía C. Burboa ◽  
Inés Poblete ◽  
...  

Deletion of pannexin-1 (Panx-1) leads not only to a reduction in endothelium-derived hyperpolarization but also to an increase in NO-mediated vasodilation. Therefore, we evaluated the participation of Panx-1-formed channels in the control of membrane potential and [Ca2+]i of endothelial cells. Changes in NO-mediated vasodilation, membrane potential, superoxide anion (O2⋅–) formation, and endothelial cell [Ca2+]i were analyzed in rat isolated mesenteric arterial beds and primary cultures of mesenteric endothelial cells. Inhibition of Panx-1 channels with probenecid (1 mM) or the Panx-1 blocking peptide 10Panx (60 μM) evoked an increase in the ACh (100 nM)-induced vasodilation of KCl-contracted mesenteries and in the phosphorylation level of endothelial NO synthase (eNOS) at serine 1177 (P-eNOSS1177) and Akt at serine 473 (P-AktS473). In addition, probenecid or 10Panx application activated a rapid, tetrodotoxin (TTX, 300 nM)-sensitive, membrane potential depolarization and [Ca2+]i increase in endothelial cells. Interestingly, the endothelial cell depolarization was converted into a transient spike after removing Ca2+ ions from the buffer solution and in the presence of 100 μM mibefradil or 10 μM Ni2+. As expected, Ni2+ also abolished the increment in [Ca2+]i. Expression of Nav1.2, Nav1.6, and Cav3.2 isoforms of voltage-dependent Na+ and Ca2+ channels was confirmed by immunocytochemistry. Furthermore, the Panx-1 channel blockade was associated with an increase in O2⋅– production. Treatment with 10 μM TEMPOL or 100 μM apocynin prevented the increase in O2⋅– formation, ACh-induced vasodilation, P-eNOSS1177, and P-AktS473 observed in response to Panx-1 inhibition. These findings indicate that the Panx-1 channel blockade triggers a novel complex signaling pathway initiated by the sequential activation of TTX-sensitive Nav channels and Cav3.2 channels, leading to an increase in NO-mediated vasodilation through a NADPH oxidase-dependent P-eNOSS1177, which suggests that Panx-1 may be involved in the endothelium-dependent control of arterial blood pressure.

1994 ◽  
Vol 267 (4) ◽  
pp. L433-L441 ◽  
Author(s):  
J. C. Magee ◽  
A. E. Stone ◽  
K. T. Oldham ◽  
K. S. Guice

Highly pure primary cultures of rat lung microvascular endothelial cells were obtained from peripheral lung tissue using a combination of selective culture strategies. The cells had a characteristic morphology consistent with an endothelial origin and were positive for a number of endothelial cell markers, including uptake of fluorescent acetylated lactate dehydrogenase, binding of the lectin Bandeiraea simplicifolia I, and positive immunofluorescence staining with two endothelial cell monoclonal antibodies. The cells behaved as microvascular endothelial cells using an in vitro angiogenesis assay. This isolation method provides a simple method for culturing the pulmonary microvasculature of the rat and these studies support the idea that endothelial cells from different vessels exhibit phenotypic heterogeneity. This method should prove useful for studying specialized endothelial cell function and differentiation in vitro.


Physiology ◽  
1991 ◽  
Vol 6 (5) ◽  
pp. 210-214
Author(s):  
MW Chapleau ◽  
G Hajduczok ◽  
FM Abboud

Arterial baroreceptors are stimulated by vascular stretch and serve to buffer fluctuations in arterial blood pressure. Factors released from endothelial cells act in a paracrine manner to modulate sensitivity of baroreceptors. Impaired endothelial cell function contributes to resetting and decreased sensitivity of baroreceptors in pathological states such as hypertension.


Author(s):  
Steven F. Kemeny ◽  
Alisa Morss Clyne

Endothelial cells line the walls of all blood vessels, where they maintain homeostasis through control of vascular tone, permeability, inflammation, and the growth and regression of blood vessels. Endothelial cells are mechanosensitive to fluid shear stress, elongating and aligning in the flow direction [1–2]. This shape change is driven by rearrangement of the actin cytoskeleton and focal adhesions [2]. Hyperglycemia, a hallmark of diabetes, affects endothelial cell function. High glucose has been shown to increase protein kinase C, formation of glucose-derived advanced glycation end-products, and glucose flux through the aldose reductase pathway within endothelial cells [3]. These changes are thought to be related to increased reactive oxygen species production [4]. While endothelial cell mechanics have been widely studied in healthy conditions, many disease states have yet to be explored. Biochemical alterations related to high glucose may alter endothelial cell mechanics.


2002 ◽  
Vol 282 (2) ◽  
pp. C395-C402 ◽  
Author(s):  
Christy-Lynn M. Cooke ◽  
Sandra T. Davidge

Peroxynitrite, a marker of oxidative stress, is elevated in conditions associated with vascular endothelial cell dysfunction, such as atherosclerosis, preeclampsia, and diabetes. However, the effects of peroxynitrite on endothelial cell function are not clear. The endothelium-derived enzymes nitric oxide synthase (NOS) and prostaglandin H synthase (PGHS) mediate vascular reactivity and contain oxidant-sensitive isoforms (iNOS and PGHS-2) that can be induced by nuclear factor (NF)-κB activation. We investigated the effect(s) of peroxynitrite on NOS and PGHS pathways in endothelial cells. We hypothesized that peroxynitrite will increase levels of iNOS and PGHS-2 through activation of NF-κB. Western immunoblots of endothelial cells show that 3-morpholinosydnonimine (SIN-1; 0.5 mM), a peroxynitrite donor, increased iNOS protein mass, which can be inhibited by pyrroline dithiocarbamate (an NF-κB inhibitor) (167 ± 24.2 vs. 78 ± 19%, P < 0.05, n = 6). SIN-1 treatment also significantly increased NF-κB translocation into endothelial cell nuclei (135 ± 10%, P < 0.05). Endothelial NOS, PGHS-1, and PGHS-2 protein levels were not altered by SIN-1. However, prostacyclin synthase protein mass, but not mRNA, was significantly reduced in SIN-1-treated endothelial cells (78 ± 8.9%, P < 0.05). Our results illustrate novel mechanisms through which peroxynitrite may modulate vascular endothelial function.


Blood ◽  
2006 ◽  
Vol 107 (3) ◽  
pp. 931-939 ◽  
Author(s):  
Cassin Kimmel Williams ◽  
Ji-Liang Li ◽  
Matilde Murga ◽  
Adrian L. Harris ◽  
Giovanna Tosato

AbstractDelta-like 4 (Dll4), a membrane-bound ligand for Notch1 and Notch4, is selectively expressed in the developing endothelium and in some tumor endothelium, and it is induced by vascular endothelial growth factor (VEGF)-A and hypoxia. Gene targeting studies have shown that Dll4 is required for normal embryonic vascular remodeling, but the mechanisms underlying Dll4 regulatory functions are currently not defined. In this study, we generated primary human endothelial cells that overexpress Dll4 protein to study Dll4 function and mechanism of action. Human umbilical vein endothelial cells retrovirally transduced with Dll4 displayed reduced proliferative and migratory responses selectively to VEGF-A. Expression of VEGF receptor-2, the principal signaling receptor for VEGF-A in endothelial cells, and coreceptor neuropilin-1 was significantly decreased in Dll4-transduced endothelial cells. Consistent with Dll4 signaling through Notch, expression of HEY2, one of the transcription factors that mediates Notch function, was significantly induced in Dll4-overexpressing endothelial cells. The γ-secretase inhibitor L-685458 significantly reconstituted endothelial cell proliferation inhibited by immobilized extracellular Dll4 and reconstituted VEGFR2 expression in Dll4-overerexpressing endothelial cells. These results identify the Notch ligand Dll4 as a selective inhibitor of VEGF-A biologic activities down-regulating 2 VEGF receptors expressed on endothelial cells and raise the possibility that Dll4 may be exploited therapeutically to modulate angiogenesis.


Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 845-845
Author(s):  
Tatiana Byzova ◽  
Juhua Chen ◽  
Payaningal R. Somanath

Abstract The major mechanism to adapt to ischemic conditions is the development of neovascularization, i.e. angiogenesis, a process driven by members of VEGF family of growth factors. Phosphoinositide 3-kinase/Akt pathway is a critical component of the signaling network that regulates endothelial cell function related to angiogenesis. VEGF treatment of endothelial cells results in rapid phosphorylation of Akt. Our studies demonstrated that Akt kinase activity is necessary for VEGF-induced and integrin-mediated endothelial cell adhesion and migration. Moreover, cell transfection with a constitutive active form of Akt (myr-Akt) leads to increased function of integrin receptors. Using Akt-1 null mice we found that Akt-1 controls VEGF-induced and integrin-dependent endothelial cell responses in vitro. Impaired endothelial cell migration and adhesion to extracellular matrix and a reduced rate of cell proliferation were observed in Akt-1 (−/−) endothelial cells compared to WT. There are three Akt isoforms with different tissue distribution, however, it appears that Akt-1 is a predominant isoform in skin and in skin microvasculature. This observation prompted us to perform series of in vivo experiments designed to assess the angiogenic response in skin in the absence of Akt-1. Angiogenesis assay using matrigel plugs revealed that the weight and hemoglobin content of matrigel plugs is about two fold higher in Akt (−/−) mice compared to WT mice. Tumor angiogenesis also appears to be enhanced in Akt(−/−) mice, resulting in the significantly lower degree of tumor necrosis. Blood vessels in Akt (−/−) mice appear to be smaller in diameter and have reduced laminin content. Our analysis revealed significant changes in blood vessel wall matrix composition of Akt (−/−) mice as compared to WT animals. These changes resulted in increased vascular permeability in skin of Akt (−/−) mice. Akt-1 is known to target multiple cellular processes including adhesive properties, cell survival, transcription and translation. It appears that the phenotype of Akt-1 (−/−) mice depends on the equilibrium between pro-angiogenic and anti-angiogenic roles of Akt-1 and reveals a central role for Akt-1 in the regulation of matrix production and maturation of blood vessels.


2007 ◽  
Vol 25 (18_suppl) ◽  
pp. 15648-15648
Author(s):  
G. Bartsch ◽  
K. Eggert ◽  
S. Loges ◽  
W. Fiedler ◽  
E. Laack ◽  
...  

15648 Background: Combinations of cytotoxic drugs lead to increased activity and minimize resistance compared to single agents in tumor therapy. Similarly, antiangiogenic treatment could be improved by combinations targeting different pathways. We investigated a combination of endogenous inhibitors using endostatin (ES), soluble Neuropilin-1 (sNP-1), and thrombospondin-2 (TSP-2) in a model of renal cell carcinoma. Methods: Porcine aortic endothelial cells have been engineered for stable production of angiogenic inhibitors by lipofection and were encapsulated in sodium alginate microbeads. Proliferation of human umbilical vein endothelial cells or Renca renal carcinoma cells was examined after incubation with different microbeads. Similarly, effects of inhibitors on endothelial cell function were tested in tube formation and in vitro wound assays. Microbeads were implanted into SCID mice with subcutaneously growing tumors derived from Renca cells or in mice developing lung metastases after intravenous injection of tumor cells. Results: Factors released from microbeads inhibited endothelial cell function but had no effect on tumor cell proliferation in vitro. In vivo, subcutaneous tumor growth was inhibited similarly by each angiogenic inhibitor alone. After 30 days mean tumor weight was 1.3 g in controls and 0.17, 0.18, 0.18g in ES, sNP-1, and TSP-2 treated mice, respectively. Tumor weight in mice treated with all three inhibitors was further reduced to 0.03g. Histological analyses confirmed antiangiogenic activity by inhibition of microvessel density in treated tumors. In a metastastic model treatment with angiogenic inhibitors induced a significant reduction in size and number of lung metastases with additive effects when factors were used in combination. Conclusions: We conclude that combination therapy targeting multiple angiogenic pathways has synergistic activity and could help to avoid resistance to single inhibitors in tumor treatment. No significant financial relationships to disclose.


Sign in / Sign up

Export Citation Format

Share Document