scholarly journals Endothelin-1-induced activation of rat renal pelvic contractions depends on cyclooxygenase-1 and Rho kinase

2010 ◽  
Vol 299 (6) ◽  
pp. R1602-R1609 ◽  
Author(s):  
Olaf Grisk ◽  
Martin Packebusch ◽  
Antje C. Steinbach ◽  
Torsten Schlüter ◽  
Ulla C. Kopp ◽  
...  

Upper urinary tract peristalsis is generated in the proximal renal pelvis that connects to the renal parenchyma at the pelvis-kidney junction. It may be exposed to the high renal endothelin-1 (ET-1) concentrations. Dietary NaCl restriction increases renal pelvic ETA receptor expression. We investigated the contribution of ETA and ETB receptors to ET-1-stimulated rat renal pelvic contractions and whether the sensitivity of renal pelvic contractile activity to ET-1 stimulation increases with dietary NaCl restriction. We tested whether ET-1-induced contractile activity depends on cyclooxygenase (COX)-1 or -2 and to what extent spontaneous as well as agonist-induced peristalsis depends on Rho kinases (ROCK). Contractions of isolated renal pelvises were investigated by myography. ET-1 concentration-dependently increased pelvic contractile activity up to 400% of basal activity. ETA but not ETB receptor blockade inhibited ET-1-induced pelvic contractions. Basal and ET-1-stimulated contractions were similar in renal pelvises from rats on a high-NaCl diet or on a NaCl-deficient diet. COX-1 inhibition reduced spontaneous and almost completely blocked the ET-1-induced pelvic contractions. ROCK inhibition reduced spontaneous and ET-1 stimulated pelvic contractile activity by 90%. RT-PCR revealed that both ROCK isoenzymes are present in the renal pelvic wall. Western blot analyses did not show increased phosphorylation of ROCK substrates myosin phosphatase target subunit 1, ezrin, radixin, and moesin in ET-1-treated isolated renal pelvises. ET-1 is a powerful ETA receptor-dependent activator of renal pelvic contractions. COX-1 and ROCK activity are required for the ET-1 effects on pelvic contractions, which are not significantly affected by dietary NaCl intake.

2010 ◽  
Vol 298 (5) ◽  
pp. H1391-H1405 ◽  
Author(s):  
Steven G. Denniss ◽  
Andrew J. Jeffery ◽  
James W. E. Rush

Hypertensive vasomotor dysfunction is defined by endothelium-dependent contractions involving prostaglandins and ROS. Since both thromboxane-prostanoid receptor (TPr) signaling and ROS activate RhoA-Rho kinase (ROCK) in vascular smooth muscle (VSM) preparations, we hypothesized that enhanced endothelium-dependent contraction in the common carotid artery (CCA) of spontaneously hypertensive rats (SHRs) is ROCK mediated. ACh-stimulated contractions were approximately twofold greater in SHRs versus normotensive Wistar-Kyoto (WKY) rats, abolished by endothelial denudation or cyclooxygenase (COX)-1 inhibition, and nearly eliminated by TPr blockade. RhoA but not ROCK-II protein expression was increased (∼50%) in the SHR CCA. Inhibition of ROCK, but not protein kinase C, caused a dose-dependent reduction in endothelium-dependent contractions to ACh across strains, with the highest dose mirroring the effect of high-dose TPr antagonism. Conversely, ROCK inhibition caused dose-dependent and endothelium- and nitric oxide-independent relaxation in CCAs precontracted with the TPr agonist U-46619. Prostacyclin was the predominant prostaglandin produced by ACh-stimulated CCAs, with greater than twofold more prostacyclin released from SHR versus WKY rats, and its production was unaffected by ROCK inhibition. RhoA activation was approximately twofold higher in quiescent SHR CCAs compared with those from WKY rats and was significantly increased by ACh stimulation. Augmentation of chemical superoxide quenching with tiron or inhibition of the NADPH oxidase-derived superoxide-producing pathway with apocynin reduced ACh-stimulated contractile activity in SHR more than in WKY rats, whereas the SOD mimetic tempol amplified the response. Exposure of CCAs to exogenous H2O2 caused contractions, similar to ACh stimulation, that were greater in SHR than in WKY rats, abolished by COX-1 inhibition, and highly attenuated by TPr blockade or ROCK inhibition. These results indicate that RhoA-ROCK may act as a molecular switch, transducing signals from endothelium-derived prostaglandin(s) and ROS, which are overproduced in SHR CCAs, to “turn on” VSM contractile pathways, thus mediating the enhanced endothelium- and endoperoxide-dependent vascular contractions characteristic of hypertension, among other cardiovascular disease states, such as diabetes and aging.


2009 ◽  
Vol 296 (5) ◽  
pp. H1408-H1415 ◽  
Author(s):  
Mohammed S. H. El-Awady ◽  
Sergey V. Smirnov ◽  
Malcolm L. Watson

The roles of intracellular calcium concentration ([Ca2+]i) and Ca2+ sensitization in lipopolysaccharide (LPS)-induced vascular smooth muscle (VSM) hyporesponsiveness are incompletely understood. To investigate these roles, contraction responses to endothelin-1 (ET-1) and 80 mM KCl; relaxation responses to nifedipine; the expression levels of mRNAs of ET-1 and its receptors (ETA or ETB); the expression levels of protein kinase C (PKC) and phosphorylation of Rho kinase (ROKα), CPI-17, and myosin phosphatase target subunit-1 (MYPT1); and changes in aortic VSM cell [Ca2+]i were measured in LPS-treated aortic rings from male Wistar rats (250–300 g). LPS (10 μg/ml, 20 h) decreased contraction induced by ET-1 (0.3–100 nM) or 80 mM KCl. LPS-induced hypocontractility was not observed in the absence of external Ca2+, but LPS-treated aorta remained hypocontractile on subsequent stepwise restoration of extracellular Ca2+ (0.01–10 mM). Vascular relaxation to nifedipine; mRNA expression levels of ET-1, ETA, or ETB; protein expression levels of PKC; and phosphorylation levels of ROKα, CPI-17, and MYPT1 were not affected by LPS. In isolated aortic VSM cells, ET-1 caused a transient initial increase in [Ca2+]i, followed by a maintained tonic increase in [Ca2+]i, which was decreased by LPS pretreatment and was dependent on external Ca2+. Subsequent restoration of extracellular Ca2+ increased [Ca2+]i, but this increase was lower in the LPS-treated group. This difference in response to extracellular Ca2+ addition was not affected by diltiazem, but was abolished by SKF-96365. Therefore, LPS induces hyporeactivity to ET-1 in rat aorta that depends on external Ca2+ influx through non-voltage-operated Ca2+ channels, but not on ET-1 receptor expression or Ca2+ sensitization.


Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 2638-2638
Author(s):  
Chi Chen ◽  
Zili He ◽  
Candice Ruby ◽  
Waqas Arslan ◽  
Madhumati Kalavar ◽  
...  

Abstract In patients or animals with established diabetes mellitus, platelets have been shown to be hyperreactive to ADP. This alteration of the platelet function occurs independent of activation of the arachidonate pathway or release of dense granule contents. In the present study, we examined the expression of the platelet ADP-binding receptor, P2Y12, in early stage of streptozocin(STZ)-induced diabetes in rats. Platelet messenger RNA (mRNA) levels for P2Y12 and cyclooxygenase-1 (COX-1) were determined by comparative RT-PCR in 7 control rats on day 0, 6 diabetic rats each on days 2, 3, 4, and 4 diabetic rats on day 7 after intraperitoneal injection of streptozocin (50 mg/kg). The plasma glucose level was 406 ± 10 mg/dl in diabetic rats, significantly greater than 151 ± 12 mg/dl in control rats. After induction of diabetes, the expression of P2Y12 mRNA significantly decreased to 76 ± 9% of the level of control on day 2, 54 ± 6% of control on day 3, reached a nadir of 28 ± 6% of control on day 4, and rose to 43 ± 10% of control on day 7. These dynamic changes of P2Y12 mRNA in platelets reflected the expression of P2Y12 mRNA in megakaryocytes isolated to a high state of purity (>96 %) from rat bone marrow. Specifically, the megakaryocytic P2Y12 mRNA expression in the diabetic rats on days 1, 2 and 3 were 74 ± 8 %, 93 ± 1%, and 117 ± 6% of those in control rats, respectively. Treatment of diabetic rats with insulin reduced the trend of decline in the platelet P2Y12 expression. By contrast, the platelet COX-1 mRNA expression measured on days 2, 3, 4 and 7 after the induction of diabetes was similar to that in the control rats. These results in diabetic rats demonstrate dynamic alterations of the mRNA expression of megakaryocyte-platelet P2Y12, but not of COX-1. The decrease in the P2Y12 receptor expression in early stage of STZ-induced diabetes may serve to attenuate the hyperaggregability of platelets and reduce the risk of vascular thrombosis.


Endocrinology ◽  
2004 ◽  
Vol 145 (11) ◽  
pp. 5280-5293 ◽  
Author(s):  
J. A. Arosh ◽  
S. K. Banu ◽  
S. Kimmins ◽  
P. Chapdelaine ◽  
L. A. MacLaren ◽  
...  

Abstract Recognition and establishment of pregnancy involve several molecular and cellular interactions among the conceptus, uterus, and corpus luteum (CL). In ruminants, interferon-τ (IFNτ) of embryonic origin is recognized as the pregnancy recognition signal. Endometrial prostaglandin F2α (PGF2α) is the luteolysin, whereas PGE2 is considered a luteoprotective or luteotrophic mediator at the time of establishment of pregnancy. The interplay between IFNτ and endometrial PGs production, transport, and signaling at the time of maternal recognition of pregnancy (MRP) is not well understood. We have studied the expression of enzymes involved in metabolism of PGE2 and PGF2α, cyclooxygenase-1 (COX-1) and COX-2, PG synthases (PGES and PGFS), PG 15-dehydrogenase, and PG transporter as well as PGE2 (EP2 and EP3) and PGF2α receptors. IFNτ influences cell-specific expression of COX-2, PGFS, EP2, and EP3 in endometrium, myometrium, and CL in a spatio-temporal and tissue-specific manner, whereas it does not alter COX-1, PGES, PG 15-dehydrogenase, PG transporter, or PGF2α receptor expression in any of these tissues. In endometrium, IFNτ decreases PGFS in epithelial cells and increases EP2 in stroma. In myometrium, IFNτ decreases PGFS and increases EP2 in smooth muscle cells. In CL, IFNτ increases PGES and decreases EP3. Together, our results show that IFNτ directly or indirectly increases PGE2 biosynthesis and EP2-associated signaling in endometrium, myometrium, and CL during MRP. Thus, PGE2 may play pivotal roles in endometrial receptivity, myometrial quiescence, and luteal maintenance, indicating polycrine (endocrine, exocrine, paracrine, and autocrine) actions of PGE2 at the time of MRP. Therefore, the establishment of pregnancy may depend not only on inhibition of endometrial PGF2α, but also on increased PGE2 production in cattle.


2021 ◽  
Vol 476 (5) ◽  
pp. 2159-2170
Author(s):  
Qiangtang Chen ◽  
Yu Wu ◽  
Yachun Yu ◽  
Junxiang Wei ◽  
Wen Huang

AbstractHIV-1 transactivator protein (Tat) induces tight junction (TJ) dysfunction and amyloid-beta (Aβ) clearance dysfunction, contributing to the development and progression of HIV-1-associated neurocognitive disorder (HAND). The Rho/ROCK signaling pathway has protective effects on neurodegenerative disease. However, the underlying mechanisms of whether Rho/ROCK protects against HIV-1 Tat-caused dysfunction of TJ and neprilysin (NEP)/Aβ transfer receptor expression have not been elucidated. C57BL/6 mice were administered sterile saline (i.p., 100 μL) or Rho-kinase inhibitor hydroxyfasudil (HF) (i.p., 10 mg/kg) or HIV-1 Tat (i.v., 100 μg/kg) or HF 30 min before being exposed to HIV-1 Tat once a day for seven consecutive days. Evans Blue (EB) leakage was detected via spectrophotometer and brain slides in mouse brains. The protein and mRNA levels of zonula occludens-1 (ZO-1), occludin, NEP, receptor for advanced glycation end products (RAGE), and low-density lipoprotein receptor-related protein 1 (LRP1) in mouse brain microvessels were, respectively, analyzed by Western blotting and quantitative real-time polymerase chain reaction (qRT-PCR) analyses. Exposure of the mice to HIV-1 Tat increased the amount of EB leakage, EB fluorescence intensity, blood–brain barrier (BBB) permeability, as well as the RAGE protein and mRNA levels, and decreased the protein and mRNA levels of ZO-1, occludin, NEP, and LRP1 in mouse brain microvessels. However, these effects were weakened by Rho-kinase inhibitor HF. Taken together, these results provide information that the Rho/ROCK signaling pathway is involved in HIV-1 Tat-induced dysfunction of TJ and NEP/Aβ transfer receptor expression in the C57BL/6 mouse brain. These findings shed some light on potentiality of inhibiting Rho/Rock signaling pathway in handling HAND.


2004 ◽  
Vol 498 (1-3) ◽  
pp. 211-217 ◽  
Author(s):  
Kansu Büyükafşar ◽  
Onur Arıkan ◽  
Mustafa Ark ◽  
Havva Kubat ◽  
Elif Özveren

Blood ◽  
2008 ◽  
Vol 112 (3) ◽  
pp. 856-865 ◽  
Author(s):  
Nitin Patel ◽  
Caryn S. Gonsalves ◽  
Punam Malik ◽  
Vijay K. Kalra

Abstract Pulmonary hypertension (PHT) develops in sickle cell disease (SCD) and is associated with high mortality. We previously showed that erythroid cells produce placenta growth factor (PlGF), which activates monocytes to induce proinflammatory cytochemokines, contributing to the baseline inflammation and severity in SCD. In this study, we observed that PlGF increased expression of endothelin-1 (ET-1) and endothelin-B receptor (ET-BR) from human pulmonary microvascular endothelial cells (HPMVECs) and monocytes, respectively. PlGF-mediated ET-1 and ET-BR expression occurred via activation of PI-3 kinase, reactive oxygen species and hypoxia inducible factor-1α (HIF-1α). PlGF increased binding of HIF-1α to the ET-1 and ET-BR promoters; this effect was abrogated with mutation of hypoxia response elements in the promoter regions and HIF-1α siRNA and confirmed by chromatin immunoprecipitation analysis. Furthermore, PlGF-mediated ET-1 release from HPMVECs and ET-BR expression in monocytes creates a PlGF–ET-1–ET-BR loop, leading to increased expression of MCP-1 and IL-8. Our studies show that PlGF-induced expression of the potent vasoconstrictor ET-1 and its cognate ET-BR receptor occur via activation of HIF-1α, independent of hypoxia. PlGF levels are intrinsically elevated from the increased red cell turnover in SCD and in other chronic anemia (eg, thalassemia) and may contribute to inflammation and PHT seen in these diseases.


2009 ◽  
Vol 102 (08) ◽  
pp. 336-346 ◽  
Author(s):  
Marilena Crescente ◽  
Gisela Jessen ◽  
Stefania Momi ◽  
Hans-Dieter Höltje ◽  
Paolo Gresele ◽  
...  

SummaryWhile resveratrol and quercetin possess antiplatelet activity, little is known on the effect of gallic acid on platelets.We studied the interactions of these three different polyphenols among themselves and with aspirin, at the level of platelet cyclooxygenase-1 (COX-1). Both functional (in vitro and in vivo) and molecular modelling approaches were used. All three polyphenols showed comparable antioxidant activity (arachidonic acid [AA]-induced intraplatelet ROS production); however, resveratrol and quercetin, but not gallic acid, inhibited AA-induced platelet aggregation. Gallic acid, similarly to salicylic acid, the major aspirin metabolite, prevented inhibition of AA-induced platelet function by aspirin but, at variance with salicylic acid, also prevented inhibition by the other two polyphenols. Molecular modelling studies, performed by in silico docking the polyphenols into the crystal structure of COX-1, suggested that all compounds form stable complexes into the COX-1 channel, with slightly different but functionally relevant interaction geometries. Experiments in mice showed that gallic acid administered before aspirin, resveratrol or quercetin fully prevented their inhibitory effect on serum TxB2. Finally, a mixture of resveratrol, quercetin and gallic acid, at relative concentrations similar to those contained in most red wines, did not inhibit platelet aggregation, but potentiated sub-inhibitory concentrations of aspirin. Gallic acid interactions with other polyphenols or aspirin at the level of platelet COX-1 might partly explain the complex,and possibly contrasting, effects of wine and other components of the Mediterranean diet on platelets and on the pharmacologic effect of lowdose aspirin.


2006 ◽  
Vol 191 (1) ◽  
pp. 263-274 ◽  
Author(s):  
Simone Odau ◽  
Christoph Gabler ◽  
Christoph Holder ◽  
Ralf Einspanier

The aim of the present study was to investigate the enzymes for the local prostaglandin (PG) biosynthesis present in the bovine oviduct during the estrous cycle to influence early reproductive events. Bovine oviducts were classified into four phases: pre-ovulatory, post-ovulatory, early-to-mid luteal, and late luteal phase, subdivided further into ipsi- or contralateral site and separated into ampulla or isthmus. Oviductal cells were gained by flushing the oviductal regions. Quantitative real-time reverse transcriptase-PCR was performed for the secretory and cytosolic phospholipases A2 (sPLA2IB, cPLA2α, and cPLA2β) and cyclooxygenases (COX-1 and COX-2) as the first step enzymes of PG synthesis. COX-1 and cPLA2β showed significant highest mRNA expression around and before ovulation compared with the luteal phase respectively. sPLA2IB and cPLA2α mRNA expression was unregulated during the estrous cycle. Regional differences in mRNA content were found for sPLA2IB with higher mRNA expression in the ampulla than in the isthmus. Western blot analysis revealed the highest COX-1 protein content in the early-to-mid luteal phase. Immunohistochemistry demonstrated that COX-1 was localized in epithelial and smooth muscle cells, whereas COX-2 was only localized in epithelial cells. COX-2 showed a differential distribution within the epithelial cell layer suggesting a regulation on a cellular level, although the COX-2 mRNA and protein amounts did not vary throughout the estrous cycle. A COX activity assay of oviductal cells revealed that COX activity originated predominantly from COX-1 than from COX-2. Treatment of primary oviductal cells with 10 pg/ml 17β-estradiol or 10 ng/ml progesterone resulted in a higher expression of COX-2 and cPLA2α, but not of the other enzymes. The expression pattern of these enzymes suggests that an estrous-cycle dependent and region-specific PG synthesis in the bovine oviduct may be required for a successful reproduction.


2008 ◽  
Vol 100 (07) ◽  
pp. 70-75 ◽  
Author(s):  
Martijn G. H. van Oijen ◽  
Santosh Sundaresan ◽  
Marc A. Brouwer ◽  
Rene H. M. te Morsche ◽  
Wessel Keuper ◽  
...  

SummaryAspirin prevents thrombotic events by inhibiting platelet cyclooxygenase-1 (COX-1), thus reducing thromboxane A2 formation and platelet aggregation. The C50T polymorphism of COX-1 is associated with an impaired inhibition of both thromboxane production and in-vitro platelet aggregation by aspirin. We studied whether this polymorphism is also associated with the risk of clinical thrombotic events in patients using aspirin. We included 496 patients admitted to our Coronary Care Unit for various indications treated with aspirin 80 mg daily. Genotyping for the C50T polymorphism demonstrated that 86.7% of the patients had the common genotype, and 13.3% had the variant (12.5% heterozygous, 0.8% homozygous). Baseline variables were well balanced, except that patients with the common genotype more frequently used aspirin prior to admission compared to those patients with the variant genotype. The composite primary endpoint of myocardial infarction, stroke, and/or cardiovascular death occurred in 98 patients (19.8%). Myocardial infarction occurred in 9.6% of patients, stroke in 1.6%, and cardiovascular death in 12.1%.The unadjusted hazard ratio (95% CI) for the primary endpoint for patients with the variant versus the common genotype was 1.07 (0.62–1.85), p=0.8.The adjusted hazard ratio was 0.86 (0.49–1.50), p=0.6. In prior laboratory studies the COX-1 C50T polymorphism was associated with an impaired inhibitory effect of aspirin on thromboxane production and platelet function. However, in this cohort of patients using low-dose aspirin for secondary prevention the polymorphism was not associated with a higher risk of atherothrombotic events.


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