Abstract 066: The Undescribed Protein Caskin2 Is a Novel Regulator of eNOS Phosphorylation and Systemic Blood Pressure

Hypertension ◽  
2015 ◽  
Vol 66 (suppl_1) ◽  
Author(s):  
Sarah B Mueller ◽  
Susan B Gurley ◽  
Christopher D Kontos
Keyword(s):  
Blood Pressure ◽  
Molecular Mechanisms ◽  
Systemic Blood Pressure ◽  
Regulatory Subunit ◽  
Systemic Blood ◽  
Homologous Expression ◽  
Ongoing Work ◽  
Inducing Factors

Disruptions in the function of the quiescent endothelial cells (ECs) that line mature vessels can both result in and contribute to the progression of numerous cardiovascular diseases including hypertension, atherosclerosis, and disorders of vascular permeability. Despite recent attention, the signaling pathways that are active in quiescent ECs remain poorly characterized relative to those that regulate EC activation. In an effort to provide mechanistic insight into these pathways, we have characterized the previously undescribed protein Caskin2, which we hypothesize is a novel regulator of EC quiescence. Caskin2 is expressed in ECs throughout the vasculature, including the aorta, coronary arteries, and renal glomeruli. In vitro, Caskin2 promotes a quiescent EC phenotype characterized by decreased proliferation and increased resistance to apoptosis-inducing factors. Caskin2 knockout mice are viable and fertile. However, preliminary radiotelemetry measurements indicate that Caskin2 knockout (KO) mice have mildly elevated systemic blood pressure (BP). Compared to wild type (WT) littermates (n=8), Caskin2 KO mice (n=7) had increased mean arterial pressure (119+/-1 vs. 113+/-1, p=0.012), systolic BP (138+/-2 vs. 132+/-2, p=0.023), and diastolic BP (99+/-1 vs. 93+/-1, p=0.014) at baseline. To explore the molecular mechanisms of Caskin2’s effects, we used mass spectrometry to identify interacting proteins. Among the 67 proteins identified were the Ser/Thr phosphatase protein phosphatase 1 (PP1) and eNOS. Using standard in vitro biochemical techniques, we demonstrated that Caskin2 acts as a PP1 regulatory subunit. Interestingly, homologous expression of Caskin2 in vitro resulted in a marked increase in phosphorylation of eNOS on S1177, which is known to promote eNOS activity, and a decrease in phosphorylation on T495, which is associated with eNOS inhibition. Finally, PP1 has been shown to dephosphorylate eNOS T495 in vitro, suggesting a molecular mechanism for our in vivo findings. Ongoing work aims to determine if the interaction of Caskin2 and PP1 is required for the Caskin2-induced increase in activating phosphorylation of eNOS and to characterize the physiological mechanisms responsible for Caskin2’s effects on BP in more detail.

Methylprednisolone on circulating eicosanoids and vasomotor tone after endotoxin

1986 ◽  
Vol 61 (1) ◽  
pp. 185-191 ◽  
Author(s):  
C. A. Hales ◽  
R. D. Brandstetter ◽  
C. F. Neely ◽  
M. B. Peterson ◽  
D. Kong ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Vascular Resistance ◽  
Systemic Blood Pressure ◽  
Physiological Effect ◽  
High Dose ◽  
Systemic Blood ◽  
Eicosanoid Production ◽  
Circulating Levels

Acute pulmonary and systemic vasomotor changes induced by endotoxin in dogs have been related, at least in part, to the production of eicosanoids such as the vasoconstrictor thromboxane and the vasodilator prostacyclin. Steroids in high doses, in vitro, inhibit activation of phospholipase A2 and prevent fatty acid release from cell membranes to enter the arachidonic acid cascade. We, therefore, administered methylprednisolone (40 mg/kg) to dogs to see if eicosanoid production and the ensuing vasomotor changes could be prevented after administration of 150 micrograms/kg of endotoxin. The stable metabolites of thromboxane B2 (TxB2) and 6-ketoprostaglandin F1 alpha (6-keto-PGF1 alpha) were measured by radioimmunoassay. Methylprednisolone by itself did not alter circulating eicosanoids but when given 2.5 h before endotoxin not only failed to inhibit endotoxin-induced eicosanoid production but actually resulted in higher circulating levels of 6-keto-PGF1 alpha (P less than 0.05) compared with animals receiving endotoxin alone. Indomethacin prevented the steroid-enhanced concentrations of 6-keto-PGF1 alpha after endotoxin and prevented the greater fall (P less than 0.05) in systemic blood pressure and systemic vascular resistance with steroid plus endotoxin than occurred with endotoxin alone. Administration of methylprednisolone immediately before endotoxin resulted in enhanced levels (P less than 0.05) of both TxB2 and 6-keto-PGF1 alpha but with a fall in systemic blood pressure and vascular resistance similar to the animals pretreated by 2.5 h. In contrast to the early steroid group in which all of the hypotensive effect was due to eicosanoids, in the latter group steroids had an additional nonspecific effect. Thus, in vivo, high-dose steroids did not prevent endotoxin-induced increases in eicosanoids but actually increased circulating levels of TxB2 and 6-keto-PGF1 alpha with a physiological effect favoring vasodilation.

scholarly journals Oh, the places you'll go! My many colored serotonin (apologies to Dr. Seuss)

2016 ◽  
Vol 311 (5) ◽  
pp. H1225-H1233 ◽  
Author(s):  
Stephanie W. Watts
Keyword(s):  
Blood Pressure ◽  
Systemic Blood Pressure ◽  
Systemic Blood ◽  
Chronic Infusion ◽  
History Of ◽  
Normotensive Subjects ◽  
Arterial Tone ◽  
Venous Vasculature

Serotonin [5-hydroxytryptamine (5-HT)] has a truly fascinating history in the cardiovascular world. Discovered in the blood, 5-HT has long been appropriately regarded as a vasoconstrictor. A multitude of in vitro studies of isolated vessels support that addition of 5-HT causes vascular contraction. In only a few cases was 5-HT a vasodilator. Moreover, the potency and threshold of 5-HT causing contraction is increased in arteries from hypertensive vs. normotensive subjects, both animal and human. As such, we and others have hypothesized that 5-HT would contribute to hypertension by elevating arterial tone. In stark contrast to these decades of findings, we observed that a chronic infusion of 5-HT into conscious rats caused a reduction in blood pressure and nearly normalized blood pressure of experimentally hypertensive rats. Going back to the early work of Irvine Page, one of the scientists who discovered 5-HT, reveals an early recognized but never understood ability of 5-HT to reduce systemic blood pressure. Our laboratory, in collaboration with colleagues around the world, has dedicated itself to understanding the mechanisms of 5-HT-induced reduction in blood pressure. This manuscript takes you through a brief history of the discovery of 5-HT, in vitro serotonergic pharmacology of blood vessels, in vivo work with 5-HT and our studies that suggests the venous vasculature, potentially in combination with small arterioles, may be important to the actions of 5-HT in reducing blood pressure. 5-HT has certainly ended up in a place I never expected it to go.

Neural mechanism underlying basilar arterial constriction by intracisternal L-NNA in anesthetized dogs

1993 ◽  
Vol 265 (1) ◽  
pp. H103-H107 ◽  
Author(s):  
N. Toda ◽  
K. Ayajiki ◽  
T. Okamura
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Cerebral Arteries ◽  
Neural Mechanism ◽  
Systemic Blood Pressure ◽  
Systemic Blood ◽  
Anesthetized Dogs ◽  
Arterial Constriction ◽  
Synthase Inhibitor

Basilar arterial diameters were angiographically measured in anesthetized dogs in which systemic blood pressure and heart rate were also monitored. Injections of NG-nitro-L-arginine (L-NNA), a NO synthase inhibitor, into the cisterna magna produced a significant, persistent decrease in arterial diameter, the effect being reversed by intracisternal injections of L-arginine. The vasoconstrictor effect of L-NNA was diminished in dogs treated with hexamethonium. On the other hand, treatment with phentolamine in a dose sufficient to lower blood pressure to a level similar to that attained with hexamethonium did not inhibit, but rather potentiated, the effect of intracisternal L-NNA. Nicotine injected into the vertebral artery significantly dilated the basilar artery. The effect was abolished by treatment with L-NNA applied intracisternally, the inhibition being reversed by the addition of L-arginine. Systemic blood pressure and heart rate were not altered by intracisternally applied L-NNA and L-arginine. These findings support the hypothesis that basilar arterial constriction caused by intracisternal L-NNA is associated with a suppression of NO synthesis in nitroxidergic nerves innervating the cerebroarterial wall rather than an elimination of basal release of NO from the endothelium. Functional importance of nitroxidergic vasodilator innervation in cerebral arteries in vivo is thus clarified.

Cardiovascular effects and cardiopulmonary plasma gradients following intravenous infusion of neuropeptide Y in humans: negative dromotropic effect on atrioventricular node conduction

2002 ◽  
Vol 103 (6) ◽  
pp. 535-542 ◽  
Author(s):  
Bengt ULLMAN ◽  
John PERNOW ◽  
Jan M. LUNDBERG ◽  
Hans ÅSTRÖM ◽  
Lennart BERGFELDT
Keyword(s):  
Heart Failure ◽  
Blood Pressure ◽  
Neuropeptide Y ◽  
Bolus Injection ◽  
Plasma Concentrations ◽  
Systemic Blood Pressure ◽  
Cardiac Conduction ◽  
Systemic Blood ◽  
Av Node

Neuropeptide Y (NPY) is co-released with noradrenaline from sympathetic nerves, has a strong vasoconstrictive action, and causes an attenuation of parasympathetic action in animal experiments. The plasma level of NPY is greatly elevated in patients with congestive heart failure, but the clinical relevance of this finding is unclear. Central haemodynamic effects, cardiac conduction system electrophysiology and coronary sinus blood flow were therefore studied in two sets of experiments, each carried out on seven healthy men. In the first series, NPY was given intravenously at doses of 3, 10 and 30pmolμmin-1μkg-1, and in the second it was given as a bolus injection of 90, 200 or 900pmol/kg, which resulted in plasma concentrations similar to those seen in heart failure patients. During continuous infusion of NPY, systemic blood pressure increased slightly, but myocardial perfusion, cardiac output, pulmonary arterial pressure, cardiac conduction intervals and atrioventricular (AV) node functional measures remained unchanged. In contrast, the bolus injection of NPY evoked prolongation and block (in four out of seven subjects) of AV node conduction, but did not affect haemodynamic variables, apart from a minor increase in systemic blood pressure. Impaired AV node conduction is a novel observation, which might reflect a baroreceptor-mediated vagal reflex, or–more likely–an NPY-induced direct negative dromotropic effect, caused by a reduction of the L-type calcium current as observed in vitro, or a combination of the two.

Method for measuring brain tissue pressure

1975 ◽  
Vol 43 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Robert M. Clark ◽  
Norman F. Capra ◽  
James H. Halsey
Keyword(s):  
Blood Pressure ◽  
Brain Tissue ◽  
Systemic Blood Pressure ◽  
Systemic Blood ◽  
Tissue Pressure ◽  
Content Type ◽  
Pressure Changes ◽  
Local Brain

✓ The authors report a method for measuring total local brain tissue pressure (BTP) using a miniature catheter transducer stereotaxically introduced into the white matter of the cat's cerebrum. Quantitative rapid phasic pressure changes were satisfactorily demonstrated. Due to some drift of baseline of the transducers and inability to perform in vivo calibration, reliable long-term quantitative pressure measurements sometimes could not be studied. The BTP from each cerebral hemisphere and the cisternal pressure (CP) were monitored during alterations of pCO2 and systemic blood pressure, and distilled H2O injection prior to and after right middle cerebral artery (MCA) ligation. The catheter transducers functioned well on chronic implantation for up to 6 weeks. Compared to the chronically implanted catheters, acutely implanted catheters responded identically except for drift. The response of intracranial pressure and CP to MCA occlusion, alterations in pCO2, and systemic blood pressure were similar. No BTP gradients appeared in response to MCA ligation, hypercapnia, hypertension, or progressive swelling of the resulting infarction.

NaCl modulates captopril effects on glomerular prostaglandin synthesis and glomerular filtration

1990 ◽  
Vol 258 (2) ◽  
pp. F382-F387
Author(s):  
M. Rathaus ◽  
E. Podjarny ◽  
A. Pomeranz ◽  
J. Bernheim
Keyword(s):  
Blood Pressure ◽  
Renal Function ◽  
Glomerular Filtration ◽  
Filtration Rate ◽  
Specific Effect ◽  
Systemic Blood Pressure ◽  
Prostaglandin Synthesis ◽  
Volume Loading ◽  
Systemic Blood

Captopril stimulates glomerular prostaglandin (PG) synthesis and increases glomerular filtration rate (GFR) in Na-repleted rats, whereas, in Na-depleted rats, it fails to stimulate PG synthesis and decreases GFR. In the present work the influence of chronic and acute NaCl loading on PG synthesis and renal function was studied in Na-depleted rats receiving captopril (LNC rats). Glomerular PGE2 and 6-keto-PGF1 alpha were not increased in LNC rats and were significantly lower than in Na-depleted rats (LN). Na repletion, while continuing captopril, increased PG synthesis above control levels. Addition of captopril in vitro to the incubation medium stimulated PGE2 synthesis in glomeruli of control rats, whereas it depressed it in LN rats. Acute loading with NaCl in LNC rats increased inulin and PAH clearances to values significantly greater than in control rats and similar to those of normal rats receiving captopril. Comparable volume loading with isotonic mannitol or 3% albumin increased inulin and PAH clearances only to control values. The specific effect of NaCl in acute loading was prevented by cyclooxygenase inhibition and was not mediated by increased systemic blood pressure. The results provide evidence that the effects of captopril on glomerular PG synthesis and renal function depend on the state of Na balance.

scholarly journals Deficiency of MicroRNA-181a Results in Transcriptome-Wide Cell Specific Changes in the Kidney that Lead to Elevated Blood Pressure and Salt Sensitivity

2021 ◽  
Author(s):  
Madeleine R. Paterson ◽  
Kristy L. Jackson ◽  
Malathi I. Dona ◽  
Gabriella E. Farrugia ◽  
Bruna Visniauskas ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Knockout Mice ◽  
Molecular Mechanisms ◽  
Salt Sensitivity ◽  
Juxtaglomerular Cells ◽  
Renal Cells ◽  
Wild Type ◽  
Knockout Mouse Model

AbstractMicroRNA miR-181a is down-regulated in the kidneys of hypertensive patients and hypertensive mice. In vitro, miR-181a is a posttranslational inhibitor of renin expression, but pleiotropic mechanisms by which miR-181a may influence blood pressure (BP) are unknown. Here we determined whether deletion of miR-181a/b-1 in vivo changes BP and the molecular mechanisms involved at the single-cell level. We developed a knockout mouse model lacking miR-181a/b-1 genes using CRISPR/Cas9 technology. Radio-telemetry probes were implanted in twelve-week-old C57BL/6J wild-type and miR-181a/b-1 knockout mice. Systolic and diastolic BP were 4-5mmHg higher in knockout compared with wild-type mice over 24-hours (P<0.01). Compared with wild-type mice, renal renin was higher in the juxtaglomerular cells of knockout mice. BP was similar in wild-type mice on a high (3.1%) versus low (0.3%) sodium diet (+0.4±0.8mmHg) but knockout mice showed salt sensitivity (+3.3±0.8mmHg, P<0.001). Since microRNAs can target several mRNAs simultaneously, we performed single-nuclei RNA-sequencing in 6,699 renal cells. We identified 12 distinct types of renal cells, all of which had genes that were dysregulated. This included genes involved in renal fibrosis and inflammation such as Stat4, Col4a1, Cd81, Flt3l, Cxcl16, Smad4. We observed up-regulation of pathways related to the immune system, inflammatory response, reactive oxygen species and nerve development, consistent with higher tyrosine hydroxylase. In conclusion, downregulation of the miR-181a gene led to increased BP and salt sensitivity in mice. This is likely due to an increase in renin expression in juxtaglomerular cells, as well as microRNA-driven pleiotropic effects impacting renal pathways associated with hypertension.

Deficiency of MicroRNA-181a Results in Transcriptome-Wide Cell-Specific Changes in the Kidney and Increases Blood Pressure

Hypertension ◽  
2021 ◽  
Vol 78 (5) ◽  
pp. 1322-1334
Author(s):  
Madeleine R. Paterson ◽  
Kristy L. Jackson ◽  
Malathi S.I. Dona ◽  
Gabriella E. Farrugia ◽  
Bruna Visniauskas ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Molecular Mechanisms ◽  
Salt Sensitivity ◽  
Juxtaglomerular Cells ◽  
Renal Cells ◽  
Cell Level ◽  
Knockout Mouse Model ◽  
Nerve Development

MicroRNA miR-181a is downregulated in the kidneys of hypertensive patients and hypertensive mice. In vitro, miR-181a is a posttranslational inhibitor of renin expression, but pleiotropic mechanisms by which miR-181a may influence blood pressure (BP) are unknown. Here, we determined whether deletion of miR-181a/b-1 in vivo changes BP and the molecular mechanisms involved at the single-cell level. We developed a KO (knockout) mouse model lacking miR-181a/b-1 genes using CRISPR/Cas9 technology. Radiotelemetry probes were implanted in 12-week-old C57BL/6J WT (wild type) and miR-181a/b-1 KO mice. Systolic and diastolic BP were 4- to 5-mm Hg higher in KO compared with WT mice over 24 hours ( P <0.01). Compared with WT mice, renal renin was higher in the juxtaglomerular cells of KO mice. BP was similar in WT mice on a high- (3.1%) versus low- (0.3%) sodium diet (+0.4±0.8 mm Hg), but KO mice showed salt sensitivity (+3.3±0.8 mm Hg; P <0.001). Since microRNAs can target several mRNAs simultaneously, we performed single-nuclei RNA sequencing in 6699 renal cells. We identified 12 distinct types of renal cells, all of which had genes that were dysregulated. This included genes involved in renal fibrosis and inflammation such as Stat4 , Col4a1 , Cd81 , Flt3l , Cxcl16 , and Smad4 . We observed upregulation of pathways related to the immune system, inflammatory response, reactive oxygen species, and nerve development, consistent with higher tyrosine hydroxylase in the kidney. In conclusion, downregulation of the miR-181a gene led to increased BP and salt sensitivity in mice. This is likely due to an increase in renin expression in juxtaglomerular cells, as well as microRNA-driven pleiotropic effects impacting renal pathways associated with hypertension.

scholarly journals Protein Phosphatase 2A Subunit PR70 Interacts with pRb and Mediates Its Dephosphorylation

2007 ◽  
Vol 28 (2) ◽  
pp. 873-882 ◽  
Author(s):  
Alessandra Magenta ◽  
Pasquale Fasanaro ◽  
Sveva Romani ◽  
Valeria Di Stefano ◽  
Maurizio C. Capogrossi ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Protein Phosphatase ◽  
Molecular Mechanisms ◽  
Protein Phosphatase 2A ◽  
Phosphate Removal ◽  
Regulatory Subunit ◽  
Phosphatase 2A ◽  
Retinoblastoma Tumor

ABSTRACT The retinoblastoma tumor suppressor protein (pRb) regulates cell proliferation and differentiation via phosphorylation-sensitive interactions with specific targets. While the role of cyclin/cyclin-dependent kinase complexes in the modulation of pRb phosphorylation has been extensively studied, relatively little is known about the molecular mechanisms regulating phosphate removal by phosphatases. Protein phosphatase 2A (PP2A) is constituted by a core dimer bearing catalytic activity and one variable B regulatory subunit conferring target specificity and subcellular localization. We previously demonstrated that PP2A core dimer binds pRb and dephosphorylates pRb upon oxidative stress. In the present study, we identified a specific PP2A-B subunit, PR70, that was associated with pRb both in vitro and in vivo. PR70 overexpression caused pRb dephosphorylation; conversely, PR70 knockdown prevented both pRb dephosphorylation and DNA synthesis inhibition induced by oxidative stress. Moreover, we found that intracellular Ca2+ mobilization was necessary and sufficient to trigger pRb dephosphorylation and PP2A phosphatase activity of PR70 was Ca2+ induced. These data underline the importance of PR70-Ca2+ interaction in the signal transduction mechanisms triggered by redox imbalance and leading to pRb dephosphorylation.

scholarly journals Endothelial Sphingolipid De Novo Synthesis Controls Blood Pressure by Regulating Signal Transduction and NO via Ceramide

Hypertension ◽  
2020 ◽  
Vol 75 (5) ◽  
pp. 1279-1288 ◽  
Author(s):  
Anna Cantalupo ◽  
Linda Sasset ◽  
Antonella Gargiulo ◽  
Luisa Rubinelli ◽  
Ilaria Del Gaudio ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Signal Transduction ◽  
Molecular Mechanisms ◽  
De Novo ◽  
Control Flow ◽  
Serine Palmitoyltransferase ◽  
Blood Pressure Homeostasis

Ceramides are sphingolipids that modulate a variety of cellular processes via 2 major mechanisms: functioning as second messengers and regulating membrane biophysical properties, particularly lipid rafts, important signaling platforms. Altered sphingolipid levels have been implicated in many cardiovascular diseases, including hypertension, atherosclerosis, and diabetes mellitus–related conditions; however, molecular mechanisms by which ceramides impact endothelial functions remain poorly understood. In this regard, we generated mice defective of endothelial sphingolipid de novo biosynthesis by deleting the Sptlc2 (long chain subunit 2 of serine palmitoyltransferase)—the first enzyme of the pathway. Our study demonstrated that endothelial sphingolipid de novo production is necessary to regulate (1) signal transduction in response to NO agonists and, mainly via ceramides, (2) resting eNOS (endothelial NO synthase) phosphorylation, and (3) blood pressure homeostasis. Specifically, our findings suggest a prevailing role of C16:0-Cer in preserving vasodilation induced by tyrosine kinase and GPCRs (G-protein coupled receptors), except for Gq-coupled receptors, while C24:0- and C24:1-Cer control flow-induced vasodilation. Replenishing C16:0-Cer in vitro and in vivo reinstates endothelial cell signaling and vascular tone regulation. This study reveals an important role of locally produced ceramides, particularly C16:0-, C24:0-, and C24:1-Cer in vascular and blood pressure homeostasis, and establishes the endothelium as a key source of plasma ceramides. Clinically, specific plasma ceramides ratios are independent predictors of major cardiovascular events. Our data also suggest that plasma ceramides might be indicative of the diseased state of the endothelium.

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