ppET-1 mRNA Research Articles

Calcitriol attenuates vascular remodeling in association with alteration of ppET-1/ETBR/eNOS and ETAR expression in acute and chronic phases of kidney ischemia-reperfusion injury in mice.

Kidney ischemia-reperfusion injury (IRI) causes acute kidney injury with increasing risk of maladaptive repair through endothelin-1 (ET-1)/endothelin type A receptor (ETAR) signaling. Calcitriol shows renoprotection in kidney fibrosis, however, its effects on vasoactive substances expression and vascular remodeling following kidney IRI remain unclear. This research aimed to investigate Calcitriol's effects on preproendothelin-1 (ppET-1), ETAR, endothelial nitric oxide synthase (eNOS) mRNA expression and vascular remodeling in acute and chronic phases of kidney IRI in mice. Twenty-five male Swiss mice were randomly divided into five groups (n=5): SO (sham-operated), IR3 (3 day kidney IRI), IR12 (12 day kidney IRI), IRD3 (3 day kidney IRI+Calcitriol 0.5 µg/kg body weight (BW)/day), and IRD12 (12 day kidney IRI+Calcitriol 0.5 µg/kg BW/day). Ischemia-reperfusion injury groups underwent bilateral renal pedicles clamping for 30 min, then reperfusion. Kidneys were harvested for Sirius Red staining to observe interstitial fibrosis and vascular remodeling, polymerase chain reaction to quantify ppET-1, endothelin type B receptor (ETBR), eNOS mRNA expression, and Western blotting to quantify ETAR protein expression. Calcitriol treatment in both phases of kidney IRI showed lower serum creatinine and ETAR protein expression, while higher eNOS and ETBR mRNA expression than IRI-only groups. Furthermore, ppET-1 mRNA expression was higher in IRD3 than IR3, but lower in IRD12 than IR12. Calcitriol also prevented vascular remodeling as indicated by lower wall thickness and higher lumen/wall area ratio than IRI-only groups.

17-Hydroxyprogesterone caproate improves hypertension and renal endothelin-1 in response to sFlt-1 induced hypertension in pregnant rats.

Preeclampsia (PE) is characterized by new onset hypertension in association with elevated soluble fms-like tyrosine kinase-1 (sFlt-1) and preproendothelin-1 (PPET-1) levels. Currently there is no effective treatment for PE except for early delivery of the fetal placental unit, making PE a leading cause for premature births worldwide. Administration of 17-hydroxyprogesterone caproate (17-OHPC) is used for prevention of recurrent preterm birth. This study was designed to test the hypothesis that 17-OHPC improves hypertension and ET-1 in response to elevated sFlt-1 in pregnant rats. sFlt-1 was infused into normal pregnant (NP) Sprague-Dawley rats (3.7μg·kg-1·day-1 for 6days, gestation days 13-19) in the presence or absence of 17-OHPC (3.32mg/kg) administered via intraperitoneal injection on gestational days 15 and 18. Mean arterial blood pressure (MAP), pup and placenta weights, renal cortex PPET-1 mRNA levels and nitrate-nitrite levels were measured on GD 19. Infusion of sFlt-1 into NP rats elevated mean arterial pressure (MAP) compared with control NP rats: 115±1 (n=13) vs. 99±2mmHg (n=12, p<0.05). 17-OHPC attenuated this hypertension reducing MAP to 102±3mmHg in sFlt-1 treated pregnant rats (n=8). Neither pup nor placental weight was affected by sFlt-1 or 17-OHPC. Importantly, renal cortex PPET-1 mRNA levels were elevated 3 fold in NP+sFlt-1 rats compare to NP rats, which decreased with 17-OHPC administration. Plasma nitrate-nitrite levels were 44±9µM in NP rats (n=9), 20±3µM in NP+sFlt-1 (n=7), which increased to 42±11µM NP+sFlt-1+17OHPC (n=6). Administration of 17-OHPC improves clinical characteristics of preeclampsia in response to elevated sFlt-1 during pregnancy.

Endothelin converting enzyme-1 (ECE-1) deletion in association with Endothelin-1 downregulation ameliorates kidney fibrosis in mice

Kidney fibrosis is a common final pathway of chronic kidney diseases, which are characterized by renal architecture damage, inflammation, fibroblast expansion and myofibroblast formation. Endothelin converting enzyme-1 (ECE-1) contributes to activation of Endothelin-1 (ET-1), a potent vasoconstrictor and pro-fibrotic substance. This study elucidated the effect of ECE-1 knockout in kidney fibrosis model in mice in association of ET-1 downregulation. Kidney fibrosis was performed in ECE-1 knockout (ECE-1 KO) and vascular endothelial derived ET-1 KO (VEETKO) mice (2 months, 20–30 g, n = 30) and their wild type (WT) littermates using unilateral ureteral obstruction (UUO) procedure. Mice were euthanized on day-7 and day-14 after UUO. Histopathological analysis was conducted for fibrosis and tubular injury. Immunostainings were done to quantify macrophages (F4/80), fibroblasts (FSP-1) and myofibroblasts (α-SMA). Monocyte Chemoattractant Protein-1 (MCP-1), ECE-1 and preproET-1 (ppET-1) mRNA expression were quantified with qRT-PCR, while Transforming Growth Factor-β1 (TGF-β1) and α-SMA protein level were quantified with Western blot. ECE-1 KO mice demonstrated reduction of ECE-1 and ppET-1 mRNA expression, attenuation of kidney fibrosis, tubular injury, MCP-1 mRNA expression and macrophage number compared to WT. Double immunostaining revealed fibroblast to myofibroblast formation after UUO, while ECE-1 KO mice had significantly lower fibroblast number and myofibroblast formation compared to WT, which were associated with significantly lower TGF-β1 and α-SMA protein levels in day-14 of UUO. VEETKO mice also demonstrated attenuation of ET-1 protein level, fibrosis and myofibroblast formation. In conclusion, ECE-1 knockout and ET-1 downregulation attenuated kidney fibrosis.

Upregulation of Endothelin-1/Endothelin A Receptor Expression Correlates with Heparanase Expression in Ovarian Carcinoma.

Heparanase and endothelin-1/endothelin A receptor (ET-1/ETAR) expressions increase in cancer. This condition enhances tumor progression and correlates with poor survival. Limited data are documented regarding the role of heparanase and ET-1/ETAR in epithelial ovarian cancer (EOC). We sought to characterize the correlation between heparanase and ET-1/ETAR in EOC. Thirty patients with benign and malignant ovarian neoplasms were recruited in this study. Neoplasm subtypes were diagnosed by pathologists. RNA extraction was done in fresh frozen neoplasms while immunohistochemical (IHC) staining was done on ETAR, heparanase, and proliferation (Ki-67 antigen) in paraffin sections. Reverse transcriptase PCR was done to quantify the expression of preproET-1 (ppET-1), ETAR, and heparanase. ETAR and heparanase histoscores were done based on IHC staining. The Independent Samples t Test, ANOVA, and correlations were used for statistical analysis. Heparanase and ETAR histoscores, ppET-1 and ETAR mRNA levels, and Ki-67 were significantly higher in the group with EOC than in the benign or borderline group, regardless of the histopathological types. The heparanase histoscore correlated with the ETAR histoscore (r=0.484, P=0.007) and the ETAR mRNA level (r=0.551, P=0.003). The level of ppET-1 mRNA correlated with both ETAR mRNA level and ETAR histoscore (r=0.603, P=0.001 and r=0.455, P=028, respectively). The ovarian neoplasms with high ppET-1 mRNA levels also tended to have high heparanase mRNA levels; however, the correlation was weak (r=0.354, P=0.07). Ki-67 correlated with the heparanase and ETAR histoscores (r=0.381, P=0.038 and r=0.477, P=0.008, respectively). Heparanase and ETAR were upregulated in EOC, and the correlation between heparanase and ETAR expressions was also elucidated in the current study.

Prostanoids counterbalance the synergism between endothelin-1 and angiotensin II in mesenteric veins of trained rats

Exercise-induced adaptations of the modulating mechanisms that influence the angiotensin (Ang II) responses assume different features depending on the venous bed. In femoral veins, exercise mobilizes vasodilator prostanoids to cooperate with NO in order to maintain reduced Ang II responses. On the other hand, exercise’s influence on the Ang II responses in veins that drain blood from the mesenteric region has been poorly described. Therefore, the present study aimed to identify the effects of a single bout of exercise, as well as exercise training, on the Ang II responses in mesenteric veins. The present study also aimed to investigate the involvement of prostanoids, NO and ET-1 in eventual exercise-induced modifications in these veins. To this end, mesenteric veins taken from resting-sedentary, exercised-sedentary, resting-trained and exercised-trained animals were studied in organ baths. In addition, the mRNA expression of prepro-endothelin-1 (ppET-1), as well as that of the ETA and ETB receptors, were quantified by real-time PCR in these veins. The results show that, either in absence or in presence of L-NAME, the Ang II responses were not different between groups. In the presence of indomethacin, higher Ang II responses were observed in the resting-trained animals than in the resting-sedentary animals. This difference, however, disappeared when L-NAME, BQ-123 or BQ-788 were added during incubation. In addition, no differences in ppET-1, ETA or ETB mRNA expression were observed between groups. Furthermore, in the presence of PD123,319, the Ang II responses in the exercised-sedentary animals were higher than those in the resting-sedentary animals. In conclusion, exercise training mobilizes endothelin-1 (ET-1) to reinforce the Ang II-induced responses mainly through ETA activation. On the other hand, vasodilator prostanoids are mobilized to act in parallel with NO in order to counterbalance the Ang II responses that have been potentiated by ET-1 in these trained animals.

Therapeutic potential of endothelin inhibitors in canine hemangiosarcoma

AimsHemangiosarcoma (HSA) that originates from vascular endothelial cells is the most common splenic malignant neoplasm in dogs, as it accounts for approximately 20% of all canine soft tissue sarcomas. In this study, inhibitory effects of endothelin receptor antagonists on the growth of HSA cells were examined using cell lines established from canine HSA. Main methodsThe preproendothelin-1 (PPET-1), endothelin type A receptor (ETA) and endothelin type B receptor (ETB) mRNA expression levels in HSA cell lines (n=5) were analyzed quantitatively by real-time RT-PCR. These levels were compared with those in HSA tissues (n=11) and those in normal splenic tissues (n=6). ETA and ETB protein expression was examined by western blot. The production and secretion of endothelin-1 (ET-1) and big ET-1 by cell lines were analyzed by measuring the levels in the culture medium by ELISA. The inhibitory effects of endothelin receptor antagonists (ambrisentan, BQ788 and bosentan) on cell growth were evaluated by WST-8 assay. Key findingsThe PPET1 and ETA mRNA expression levels were elevated in HSA tissues and HSA cell lines compared with normal tissues. In cell lines, the production of ET-1 and big ET-1 peptide as well as the expression of ETA protein were detected, but the levels of ETB were not measured. Ambrisentan and bosentan inhibited growth activity in cell lines. Ambrisentan was more effective than bosentan. SignificanceThese findings demonstrate the importance of the ETA axis in canine HSA as well as the potential of ETA inhibitors in the treatment of canine HSA.

Big endothelin-1 as a tumour marker for canine haemangiosarcoma

Haemangiosarcoma (HSA) is an important malignant neoplasm of dogs that originates from vascular endothelial cells. This study explored the suitability of using serum big endothelin-1 (ET-1) as a tumour marker for canine spontaneous HSA. Serum big ET-1 was measured in dogs with splenic HSA (n = 14), splenic malignant tumours other than HSA (n = 10), benign splenic lesions (n = 11) and normal healthy dogs (n = 17) by ELISA. Serum big ET-1 levels in dogs with HSA were significantly (P < 0.01) higher than in other dogs. High sensitivity (100%, 95% confidence interval 86–100%) and specificity (95%, 95% confidence interval 86–95%) for HSA diagnosis were obtained using a cut-off of 17 pg/mL according to receiver operating characteristic (ROC) curves (area under ROC curve 0.93). PPET1, ETA, VEGF and Hif1-α mRNA expression, measured by real-time PCR, were elevated in HSA compared with normal tissues. These findings suggest that elevated serum big ET-1 could be used as a diagnostic marker for canine HSA.

Resveratrol inhibits the intracellular calcium increase and angiotensin/endothelin system activation induced by soluble uric acid in mesangial cells.

Resveratrol (Resv) is natural polyphenol found in grapes. This study evaluated the protective effect of Resv against the effects of uric acid (UA) in immortalized human mesangial cells (ihMCs). ihMCs were preincubated with Resv (12.5 µM) for 1 h and treated with UA (10 mg/dL) for 6 or 12 h. The intracellular calcium concentration [Ca2+]i was quantified by fluorescence using flow cytometry. Angiotensinogen (AGT) and pre-pro endothelin-1 (ppET-1) mRNA were assayed by quantitative real-time RT-PCR. Angiotensin II (AII) and endothelin-1 (ET-1) were assayed by ELISA. UA significantly increased [Ca2+]i. Pre-incubation with Resv significantly reduced the change in [Ca2+]i induced by UA. Incubation with UA for 6 or 12 h also increased AGT mRNA expression and AII protein synthesis. Resv blunted these increases in AGT mRNA expression and AII protein. Incubation with UA in the ihMCs increased ppET-1 expression and ET-1 protein synthesis at 6 and 12 h. When ihMCs were pre-incubated with Resv, UA had a significantly diminished effect on ppET-1 mRNA expression and ET-1 protein synthesis at 6 and 12 h, respectively. Our results suggested that UA triggers reactions including AII and ET-1 production in mesangial cells. The renin-angiotensin system may contribute to the pathogenesis of renal function and chronic kidney disease. Resv can minimize the impact of UA on AII, ET-1 and the increase of [Ca2+]i in mesangial cells, suggesting that, at least in part, Resv can prevent the effects of soluble UA in mesangial cells.

Exercise reduces angiotensin II responses in rat femoral veins

The control of blood flow during exercise involves different mechanisms, one of which is the activation of the renin-angiotensin system, which contributes to exercise-induced blood flow redistribution. Moreover, although angiotensin II (Ang II) is considered a potent venoconstrictor agonist, little is known about its effects on the venous bed during exercise. Therefore, the present study aimed to assess the Ang II responses in the femoral vein taken from sedentary and trained rats at rest or subjected to a single bout of exercise immediately before organ bath experiments. Isolated preparations of femoral veins taken from resting-sedentary, exercised-sedentary, resting-trained and exercised-trained animals were studied in an organ bath. In parallel, the mRNA expression of prepro-endothelin-1 (ppET-1), as well as the ETA and ETB receptors, was quantified by real-time PCR in this tissue. The results show that, in the presence of L-NAME, Ang II responses in resting-sedentary animals were higher compared to the other groups. However, this difference disappeared after co-treatment with indomethacin, BQ-123 or BQ-788. Moreover, exercise reduced ppET-1 mRNA expression. These reductions in mRNA expression were more evident in resting-trained animals. In conclusion, either acute or repeated exercise adapts the rat femoral veins, thereby reducing the Ang II responses. This adaptation is masked by the action of locally produced nitric oxide and involves, at least partially, the ETB- mediated release of vasodilator prostanoids. Reductions in endothelin-1 production may also be involved in these exercise-induced modifications of Ang II responses in the femoral vein.

Transforming Growth Factor-β2 Induces Synthesis and Secretion of Endothelin-1 in Human Trabecular Meshwork Cells

Analysis of aqueous humor from patients with primary open-angle glaucoma (POAG) revealed marked increases in the content of endothelin-1 (ET-1) and transforming growth factor-beta (TGF-β). We determined the consequences of TGF-β signaling on ET-1 expression and secretion by human trabecular meshwork (TM) cells. Primary or transformed (NTM5 and GTM3) human TM cells conditioned in serum-free media were incubated in the absence or presence of TGF-β1 or -β2. Relative changes in preproendothelin (ppET)-1 mRNA content and secreted ET-1 peptide were quantified by real-time PCR and ELISA, respectively. In some experiments, TGF-β or ET-1 receptor antagonists, or Rho G-protein inhibitors, were evaluated for effects on TGF-β signaling. Filamentous actin organization was visualized by phalloidin. Primary or transformed human TM cells cultured in the presence of TGF-β1 or -β2 exhibit a marked (>8-fold) increase in ppET-1 mRNA content compared to vehicle controls. Coincubation with SB-505124, an inhibitor of TGFβRI/ALK-5 signaling, prevented TGF-β-mediated ppET-1 mRNA expression. In contrast, coincubation with ET(A) (BQ-123) or ET(B) (BQ-788) receptor antagonists had no effect on TGF-β-mediated ppET-1 mRNA expression. TGF-β1 and -β2 each elicited a robust (>7-fold) secretion of ET-1 while enhancing stress fiber organization. Inhibition of Rho signaling attenuated TGF-β-mediated increases in ppET-1 mRNA content, ET-1 secretion, and stress fiber organization. TGF-β, signaling through the TGFβRI/ALK-5 receptor, elicits marked increases in ET-1 mRNA content and ET-1 secretion from cultured primary or transformed human TM cells. Elevated levels of TGF-β2 present in AH of POAG patients may elevate intraocular pressure, in part, by eliciting aberrant Rho G-protein dependent cell contraction, and increasing ET-1 synthesis and secretion, in human TM cells.

β2-adrenoceptors and muscarinic receptors mediate opposing effects on endothelin-1 expression in human lung fibroblasts

Human lung fibroblasts are a potential source of endothelin-1 (ET-1), a pro-fibrotic mediator. The present study explored possible muscarinic and β-adrenergic modulations of ET-1 expression in human lung fibroblasts. MRC-5 human lung fibroblasts were cultured. Expression of prepro-endothelin-1 (ppET-1) mRNA was determined by quantitative real time PCR. [3H]-Proline incorporation was determined as measure of collagen synthesis. The muscarinic agonist oxotremorine induced, in a tiotropium-sensitive manner, a three-fold increase in ppET-1 mRNA. The β2-adrenoceptor agonist olodaterol caused a reduction of ppET-1 mRNA by 45%. Olodaterol also opposed the stimulatory effect of oxotremorine. The effect of olodaterol was mimicked by the protein kinase A agonist 6-Bnz-cAMP, whereas the Epac (exchange protein activated by cAMP) agonist 8-CPT-2′-O-Me-cAMP was less effective. Transforming growth factor-β1 (TGF-β, 0.3 and 1ng/ml) induced a three- and eight-fold increase in pp-ET-1 mRNA, respectively. Olodaterol opposed the effect of 0.3, but not that of 1ng/ml TGF-β. Likewise, 6-Bnz-cAMP opposed the effect of 0.3, but not that of 1ng/ml TGF-β. TGF-β inhibited β2-adrenoceptor mRNA expression, maximally by 90%. Muscarinic agonist-induced stimulation of [3H]-proline incorporation was attenuated by the endothelin ET1 receptor antagonist bosentan. In conclusion, ET-1 expression in human lung fibroblasts is regulated by stimulatory muscarinic receptors and inhibitory β2-adrenoceptors. Since muscarinic up-regulation of ET-1 contributes to pro-fibrotic effects of muscarinic stimuli, inhibition of ET-1 expression could contribute to long-term beneficial effects of long-acting β2-adrenoceptor agonists and long-acting muscarinic antagonists. However, excessive exposure to TGF-β results in loss of β-adrenoceptor expression and function of its down-stream signaling.

Thrombin-Induced Endothelin-1 Synthesis and Secretion in Retinal Pigment Epithelial Cells Is Rho Kinase Dependent

The retinal pigment epithelium (RPE) is a major source for endothelin-1 (ET-1), a potent vasoactive peptide, at the outer blood–retinal barrier. Factors that regulate ET-1 synthesis at this site may help identify its normal function and its role in pathologic states accompanying retinal injury. Thrombin is one such factor that might act on the RPE after injury and breakdown of the blood–retinal barrier. The present study was conducted to identify signaling intermediates in thrombin-induced ET-1 synthesis and secretion in primary human RPE (hRPE) and transformed RPE cells (ARPE-19) and a possible pharmacological strategy to block excess release of ET-1. Cultured hRPE cells were treated with different concentrations of thrombin and thrombin receptor agonists, and a time course to measure levels of preproET-1 (ppET-1) mRNA and secreted mature ET-1 was performed. Levels of secondary messengers [Ca²+]i and RhoA were measured and pharmacologically inhibited to determine how receptor-mediated thrombin activity lead to changes in ET-1 levels. Thrombin primarily acts via the protease-activated receptor-1 (PAR-1) subtype in RPE to induce ET-1 synthesis. Thrombin and other receptor agonists increased both [Ca²+]<]i and active RhoA. PAR-1-dependent rho/Rho kinase activation led to increase in ppET-1 mRNA and mature ET-1 secretion. Transient intracellular calcium mobilization and protein kinase C activation by thrombin play a minor role, if any, in ET-1 synthesis in RPE. Instead, rho/Rho kinase activation after PAR-1 stimulation strongly increased ppET-1 mRNA and ET-1 secretion in hRPE cells.

IL-17 mediates articular hypernociception in antigen-induced arthritis in mice

IL-17 is an important cytokine in the physiopathology of rheumatoid arthritis (RA). However, its participation in the genesis of nociception during RA remains undetermined. In this study, we evaluated the role of IL-17 in the genesis of articular nociception in a model of antigen (mBSA)-induced arthritis. We found that mBSA challenge in the femur–tibial joint of immunized mice induced a dose- and time-dependent mechanical hypernociception. The local IL-17 concentration within the mBSA-injected joints increased significantly over time. Moreover, co-treatment of mBSA challenged mice with an antibody against IL-17 inhibited hypernociception and neutrophil recruitment. In agreement, intraarticular injection of IL-17 induced hypernociception and neutrophil migration, which were reduced by the pre-treatment with fucoidin, a leukocyte adhesion inhibitor. The hypernociceptive effect of IL-17 was also reduced in TNFR1 −/− mice and by pre-treatment with infliximab (anti-TNF antibody), a CXCR1/2 antagonist or by an IL-1 receptor antagonist. Consistent with these findings, we found that IL-17 injection into joints increased the production of TNF-α, IL-1β and CXCL1/KC. Treatment with doxycycline (non-specific MMPs inhibitor), bosentan (ET A/ET B antagonist), indomethacin (COX inhibitor) or guanethidine (sympathetic blocker) inhibited IL-17-induced hypernociception. IL-17 injection also increased PGE 2 production, MMP-9 activity and COX-2, MMP-9 and PPET-1 mRNA expression in synovial membrane. These results suggest that IL-17 is a novel pro-nociceptive cytokine in mBSA-induced arthritis, whose effect depends on both neutrophil migration and various pro-inflammatory mediators, as TNF-α, IL-1β, CXCR1/2 chemokines ligands, MMPs, endothelins, prostaglandins and sympathetic amines. Therefore, it is reasonable to propose IL-17 targeting therapies to control this important RA symptom.

Hormone therapy modulates ETA mRNA expression in the aorta of ovariectomised New Zealand White rabbits

Objective. To study the effect of 17β-estradiol (E2) or conjugated equine estrogens (CEE) alone and in combination with norethisterone acetate (NETA) or medroxyprogesterone acetate (MPA) on the endothelin-1 (ET-1) system.Methods. New Zealand White rabbits were treated with E2, CEE, E2 + NETA, CEE + MPA or placebo. The thoracic aorta and the epicardial coronary artery were used for mRNA expression and myograph analyses, respectively.Results. E2 and CEE alone significantly reduced ET-1 receptor subtype A (ETA) mRNA expression compared with placebo treatment. The E2-induced reduction in ETA mRNA expression persisted with the co-administration of NETA, but the CEE induced reduction in ETA mRNA expression was not maintained with the co-administration of MPA. Treatment with CEE alone significantly increased endotelin-1 converting enzyme (ECE) mRNA expression and CEE combined with MPA reduced prepro-endothelin-1 (ppET-1) mRNA expression when compared with placebo. ET-1 receptor subtype B mRNA expression and ET-1 induced vasocontraction was unaffected by treatment.Conclusions. E2 and CEE treatment exert potentially beneficial vascular effects through regulation of the ETA receptor. The effect was maintained with the co-administration of NETA, but not MPA. The differential effects of specific hormone components may explain the variable effects of hormone therapy on the arterial wall.

Endogenous Aldosterone Contributes to Acute Angiotensin II-Stimulated Plasminogen Activator Inhibitor-1 and Preproendothelin-1 Expression in Heart But Not Aorta

To test the hypothesis that angiotensin (Ang) II induces profibrotic gene expression through endogenous aldosterone, we measured the effect of 4 h infusion (600 ng/kg x min) of Ang II on tissue mRNA expression of plasminogen activator inhibitor 1 (PAI-1), preproendothelin-1 (ppET-1), TGF-beta, and osteopontin in wild-type (WT), aldosterone synthase-deficient (AS(-/-)), and AS(-/-) mice treated with aldosterone (either 500 ng/d for 7 d or 250 ng as a concurrent 4 h infusion). Ang II increased aldosterone in WT (P < 0.001) but not in AS(-/-) mice. Aldosterone (7 d) normalized basal aldosterone concentrations in AS(-/-) mice; however, there was no further effect of Ang II on aldosterone (P = NS). Basal cardiac and aortic PAI-1 and ppET-1 expression were similar in WT and AS(-/-) mice. Ang II-stimulated PAI-1 (P < 0.001) and ppET-1 expression (P = 0.01) was diminished in the heart of AS(-/-) mice; treatment with aldosterone for 4 h or 7 d restored PAI-1 and ppET-1 mRNA responsiveness to Ang II in the heart. Ang II increased PAI-1 (P = 0.01) expression in the aorta of AS(-/-) as well as WT mice. In the kidney, basal PAI-1, ppET-1, and TGF-beta mRNA expression was increased in AS(-/-) compared with WT mice and correlated with plasma renin activity. Ang II did not stimulate osteopontin or TGF-beta expression in the heart or kidney. Endogenous aldosterone contributes to the acute stimulatory effect of Ang II on PAI-1 and ppET-1 mRNA expression in the heart; renin activity correlates with basal profibrotic gene expression in the kidney.

Transcriptional and post-transcriptional regulation of preproendothelin-1 by plaque-prone hemodynamics

Objective Plaque-prone areas are exposed to a particular hemodynamic environment characterized by a low mean shear stress value and a cyclic reversal flow. This mechanical environment, also termed oscillatory shear stress (OSS), induces the expression of several pro-atherogenic genes in the endothelial cells including the preproendothelin-1 (ppET-1) gene. The present paper investigates the molecular mechanisms of this induction. Methods and results Several deletional mutants of ppET-1 gene promoter were cloned upstream of a luciferase gene and transiently transfected in bovine arterial endothelial cells that were further exposed to plaque-prone hemodynamics. After 24 h of flow exposure, analysis of the transfected cells showed that a proximal promoter of 156 base pairs length retained OSS responsiveness. Mutation of an activator protein-1 (AP-1) binding site present in this minimal promoter completely abolished its activation by OSS. Consistently, electrophoresis mobility shift assay revealed a sustained activation of AP-1 transcription factor in endothelial cells exposed to OSS. In addition to the transcriptional activation, we demonstrated that OSS also induces a stabilization of ppET-1 mRNA through the 3′-untranslated region (3′-UTR) of this gene. Fluvastatin, a drug known to improve endothelial function, was shown to prevent OSS up-regulation of the ppET-1 gene expression. Under this flow condition, fluvastatin affects ppET-1 gene expression via inhibition of its promoter activity without affecting ppET-1 mRNA stability. Conclusions The present study demonstrate that plaque-prone hemodynamic induces ppET-1 gene expression by both transcriptional and post-transcriptional mechanisms via an activation of AP-1 transcriptional factor and stabilization of mRNA. The transcriptional up-regulation of ppET-1 was shown to be fluvastatin sensitive.

IL-15 mediates immune inflammatory hypernociception by triggering a sequential release of IFN-γ, endothelin, and prostaglandin

IL-15 is closely associated with inflammatory diseases. IL-15 targeting is effective in treating experimental and clinical rheumatoid arthritis (RA). Because hyperalgesia accompanies RA, we investigated the ability of IL-15 to induced nociceptor sensitization (hypernociception). We report here that IL-15 induced time- and dose-dependent mechanical hypernociception in mice. IL-15-induced hypernociception was inhibited by treatment with a dual endothelin receptor type A (ET(A))/endothelin receptor type B (ET(B)) antagonist (bosentan), ET(A) receptor antagonist (BQ123), or cyclooxygenase inhibitor (indomethacin). Moreover, IL-15 failed to induce hypernociception in IFN-gamma(-/-) mice, suggesting that IL-15 mediated hypernociception via an IFN-gamma-, endothelin (ET)-, and prostaglandin-dependent pathway. Consistent with this finding, IFN-gamma and ET-1 induced dose- and time-dependent mechanical hypernociception that was inhibited by BQ123 or indomethacin but not BQ788 (an ET(B) receptor antagonist). IFN-gamma induced the production of ET-1 and the expression of its mRNA precursor (preproET-1, PPET-1). Moreover, IL-15 also induced ET-1 production and PPET-1 mRNA expression in an IFN-gamma-dependent manner. Prostaglandin E(2) (PGE(2)) production was induced by IL-15, IFN-gamma, or ET-1. We also found that hypernociception induced by ovalbumin (OVA) in OVA-immunized mice was significantly diminished by treatment with sIL-15Ralpha (soluble IL-15 receptor alpha-chain), bosentan, BQ123, or indomethacin. Furthermore, OVA challenge induced the expression of PPET-1 mRNA in WT mice but not in IFN-gamma(-/-) mice. The PPET-1 mRNA expression was also inhibited by sIL-15Ralpha pretreatment. Therefore, our results demonstrate the sequential mechanical hypernociceptive effect of IL-15 --> IFN-gamma --> ET-1 --> PGE(2) and suggest that these molecules may be targets of therapeutic intervention in antigen-induced hypernociception.

The Effects of Selective Cyclooxygenase-2 Inhibitor and Prostaglandin E2Receptor Agonists on the Endothelin Axis of Prostate Cancer Cells

Purpose: The enhanced expression of the cyclooxygenase-2 (COX-2), prostaglandin E2 receptor (EPs) and endothelin-1 (ET-1) axis is known to play a significant role in the development and progression of several malignancies. To date, little work has been done to investigate the relationships between the COX-2, EPs and ET-1 axis in prostate cancer (PC) cells. The aim of this study is to investigate the expression of preproET-1 (PPET-1), ET-1 receptor A (ETAR), and endothelin converting enzyme-1 (ECE-1) in the PC cell lines and to evaluate the effects of COX-2 and EPs on the expression of PPET-1, ETAR, and ECE-1. Materials and Methods: Two PC cell lines, PC-3 and DU-145 cells were used for this study. By performing reverse transcription polymerase chain reaction (RT-PCR), the mRNA expressions of PPET-1, ETAR and ECE-1 were detected, and then the mRNA expressions of PPET-1, ETAR and ECE-1 were detected after being treating the cells with selective COX-2 inhibitor (NS-398), or EP2 (butaprost) and EP4 (misoprostol), which are both agonist of 10, 10 and 10M. Results: PPET-1, ETAR and ECE-1 mRNA were expressed in both cell lines. After NS-398 treatment, only the PPET-1 mRNA expression was decreased at 4, 8 and 12 hours in the PC-3 cells. EP2 and EP4 agonist induced an increase for the PPET-1, ETAR and ECE-1 mRNA expressions, compared with the NS-398 treated group (control), in the PC-3 cells. Conclusions: ET-1/ETAR and ECE-1, whose expressions are increased by EP2 and EP4, may play key roles in the development and progression of PC via COX-2. A combination treatment with selective inhibitors for COX-2, EPs and ETAR would be novel approach to prostate cancer therapy. (Korean J Urol 2006;47:195-200)

775 Administration of ghrelin modulates its myocardial expression and attenuates neurohumoral activation in MCT-induced pulmonary hypertension

We recently showed that ghrelin (ghr), attenuates pulmonary hypertension (PH), right ventricular and pulmonary vascular remodelling in monocrotaline (MCT) rats. We also showed, in this model of selective right ventricular (RV) overload, failure of the non-overloaded left ventricle (LV), which correlated with autocrine/paracrine activation. In the present study we evaluated the effects of ghr on biventricular function, myocardial expression of ghr and autocrine/paracrine activation in MCT model. Adult Wistar rats were injected with MCT (60 mg/Kg, sc) or just the vehicle (day 0). One week later, animals treated with MCT were randomly divided and treated with ghr (100 ~g/Kg, BID, sc) or with a similar volume of vehicle. The study resulted in 3 groups: (i) control (Ctrl, n=7), (ii) MCT (n=9), (iii) MCT+ghr (n=9). At days 21-25 the animals were instrumented to record RV and LV peak systolic (Psys) pressures, dP/dtmax and time constant Tau. RV and LV transmural free-wall samples were collected to quantify, by real time RT-PCR, ghrelin, ppET-1 and ACE mRNA levels, which were normalized for GAPDH and expressed in arbitrary units (AU). Results: Results are presented as meand=SEM, are summarized in the table l(P<0.05: a vs. Ctrl; b vs. MCT).

Cloning of cDNA Encoding Canine Endotherlin Receptors and Their Expressions in Normal Tissues

The receptors for endothelin (ET) family, ETA and ETB, were molecularly cloned and the expression of ETA and ETB as well as preproendothelin-1 (PPET-1, precursor of ET-1) was examined in normal canine tissues by RT-PCR. The entire open reading frames of the canine ETA and ETB were shown to encode 427 and 442 amino acid residues, respectively, showing from 87.4 to 97.3% sequence similarity to human, mouse, and rat counterparts. ETA and ETB mRNAs were ubiquitously expressed in a variety of canine tissues in this study and PPET-1 mRNA was detected in the tissues except for heart and liver. It was speculated that ET could play an important role in physiological events in most of the organs.