Comparison of MEK/ERK pathway inhibitors on the upregulation of vascular G-protein coupled receptors in rat cerebral arteries

Organ culture is an in vitro method for investigating cellular mechanisms involved in upregulation of vasocontractile G-protein coupled receptors. We hypothesize that mitogen-activated-protein kinase (MEK) and/or extracellular-signal-regulated kinase (ERK) specific inhibitors will attenuate the G-protein coupled receptor expression following organ culture. Rat cerebral arteries were incubated 48 h in the presence of MEK/ERK specific inhibitors U0126, PD98059, SL327, or AG126 for different time periods. Contractile responses by activation of endothelin receptor type A and type B. serotonin receptor 5-FIT18, prostanoid TP receptor, and angiotensin II receptor type 1 and type 2 were investigated. Results were verified by measurement of mRNA with real time PCR and by protein immunohistochemistry. Organ culture induced transcriptional upregulation of endothelin ETB receptor and of serotonin 5-HTIB receptor on translational level and increased respective contractions. The prostanoid TP receptor mediated contraction curve was left-wards shifted by organ culture. Organ culture was associated with elevated pERK1/2 in the vascular smooth muscle cells: the MEK1/2 inhibitor U0126 attenuated the endothelin ETB receptor mediated contraction at post-translational level or by changing the receptor affinities. The serotonin 5-HT,B receptor and prostanoid TP receptor mediated contractions were abolished by U0126. Administration of U0126 6 h after start of incubation blocked the receptor upregulation. In conclusion, MEK specific inhibitor U0126 is a potent inhibitor of G-protein coupled receptor alteration seen during organ culture. Given the ability to inhibit G-protein coupled receptor alteration at the clinically relevant time-point 6 h post incubation makes it an attractive therapeutic agent for in vivo studies. (C) 2010 Elsevier By. All rights reserved

The role of tumor necrosis factor-α and TNF-α receptors in cerebral arteries following cerebral ischemia in rat

<p>Abstract</p> <p>Background</p> <p>Tumour necrosis factor-α (TNF-α) is a pleiotropic pro-inflammatory cytokine, which is rapidly upregulated in the brain after injury. TNF-α acts by binding to its receptors, TNF-R1 (p55) and TNF-R2 (p75), on the cell surface. The aim of this study was first to investigate if there is altered expression of TNF-α and TNF-α receptors in cerebral artery walls following global or focal ischemia, and after organ culture. Secondly, we asked if the expression was regulated via activation of the MEK-ERK1/2 pathway.</p> <p>Methods</p> <p>The hypothesis was tested <it>in vivo </it>after subarachnoid hemorrhage (SAH) and middle cerebral artery occlusion (MCAO), and <it>in vitro </it>by organ culture of isolated cerebral arteries. The localization and amount of TNF-α, TNF-α receptor 1 and 2 proteins were analysed by immunohistochemistry and western blot after 24 and 48 h of organ culture and at 48 h following SAH or MCAO. In addition, cerebral arteries were incubated for 24 or 48 h in the absence or presence of a B-Raf inhibitor (SB386023-b), a MEK- inhibitor (U0126) or an NF-κB inhibitor (IMD-0354), and protein expression evaluated.</p> <p>Results</p> <p>Immunohistochemistry revealed enhanced expression of TNF-α, TNF-R1 and TNF-R2 in the walls of cerebral arteries at 48 h after MCAO and SAH compared with control. Co-localization studies showed that TNF-α, TNF-R1 and TNF-R2 were primarily localized to the cell membrane and the cytoplasm of the smooth muscle cells (SMC). There was, in addition, some expression of TNF-R2 in the endothelial cells. Immunohistochemistry and western blot analysis showed that these proteins were upregulated after 24 and 48 h in culture, and this upregulation reached an apparent maximum at 48 h of organ culture. Treatment with U0126 significantly reduced the enhanced SMC expression of TNF-α, TNF-R1 and TNF-R2 immunoreactivities after 24 and 48 h of organ culture. The Raf and NF-κB inhibitors significantly reduced organ culture induced TNF-α expression while they had minor effects on the TNF-α receptors.</p> <p>Conclusion</p> <p>The present study shows that cerebral ischemia and organ culture induce expression of TNF-α and its receptors in the walls of cerebral arteries and that upregulation is transcriptionally regulated via the MEK/ERK pathway.</p

Treatment of migraine attacks based on the interaction with the trigemino-cerebrovascular system

Primary headaches such as migraine are among the most prevalent neurological disorders, affecting up to one-fifth of the adult population. The scientific work in the last decade has unraveled much of the pathophysiological background of migraine, which is now considered to be a neurovascular disorder. It has been discovered that the trigemino-cerebrovascular system plays a key role in migraine headache pathophysiology by releasing the potent vasodilator calcitonin gene-related peptide (CGRP). This neuropeptide is released in parallel with the pain and its concentration correlates well with the intensity of the headache. The development of drugs of the triptan class has provided relief for the acute attacks but at the cost of, mainly cardiovascular, side effects. Thus, the intention to improve treatment led to the development of small CGRP receptor antagonists such as olcegepant (BIBN4096BS) and MK-0974 that alleviate the acute migraine attack without acute side events. The purpose of this review is to give a short overview of the pathological background of migraine headache and to illustrate the mechanisms behind the actions of triptans and the promising CGRP receptor blockers

Comparison of the vasodilator responses of isolated human and rat middle meningeal arteries to migraine related compounds

Background: Migraine attacks occur spontaneously in those who suffer from the condition, but migraine-like attacks can also be induced artificially by a number of substances. Previously published evidence makes the meninges a likely source of migraine related pain. This article investigates the effect of several vasodilators on meningeal arteries in order to find a connection between the effect of a substance on a meningeal vessel and its ability to artificially induce migraine. Methods: A myograph setup was used to test the vasodilator properties of the substances acetylcholine (ACh), sodium nitroprusside (SNP), sildenafil, prostaglandin E2 (PGE2), pituitary adenylate cyclase activating peptide-38 (PACAP-38), calcitonin gene-related peptide (CGRP) and NaCl buffer on meningeal arteries from human and rat. An unpaired t-test was used to statistically compare the mean Emax(%) at the highest concentration of each substance to the Emax(%) of NaCl buffer. Results: In the human experiments, all substances except PACAP-38 had an Emax (%) higher than the NaCl buffer, but the difference was only significant for SNP and CGRP. For the human samples, clinically tested antimigraine compounds (sumatriptan, telcagepant) were applied to the isolated arteries, and both induced a significant decrease of the effect of exogenously administrated CGRP. In experiments on rat middle meningeal arteries, pre-contracted with PGF2α, similar tendencies were seen. When the pre-contraction was switched to K+ in a separate series of experiments, CGRP and sildenafil significantly relaxed the arteries. Conclusions: Still no definite answer can be given as to why pain is experienced during an attack of migraine. No clear correlation was found between the efficacy of a substance as a meningeal artery vasodilator in human and the ability to artificially induce migraine or the mechanism of action. Vasodilatation could be an essential trigger, but only in conjunction with other unknown factors. The vasculature of the meninges likely contributes to the propagation of the migrainal cascade of symptoms, but more research is needed before any conclusions can be drawn about the nature of this contribution

Involvement of calcitonin gene-related peptide in migraine: regional cerebral blood flow and blood flow velocity in migraine patients

Calcitonin gene-related peptide (CGRP)-containing nerves are closely associated with cranial blood vessels. CGRP is the most potent vasodilator known in isolated cerebral blood vessels. CGRP can induce migraine attacks, and two selective CGRP receptor antagonists are effective in the treatment of migraine attacks. It is therefore important to investigate its mechanism of action in patients with migraine. We here investigate the effects of intravenous human alpha-CGRP (hαCGRP) on intracranial hemodynamics. In a double-blind, cross-over study, the effect of intravenous infusion of hαCGRP (2 μg/min) or placebo for 20 min was studied in 12 patients with migraine without aura outside attacks. Xenon-133 inhalation SPECT-determined regional cerebral blood flow (rCBF) and transcranial Doppler (TCD)-determined blood velocity (Vmean) in the middle cerebral artery (MCA), as well as the heart rate and blood pressure, were the outcome parameters. No change of rCBF was observed at the end of infusion [1.2% ± 1.7 with hαCGRP, vs. −1.6% ± 3.1 with placebo (mean ± SD)] (P = 0.43). Vmean in MCA decreased to 13.5% ± 3.6 with hαCGRP versus 0.6% ± 1.8 with placebo (P < 0.005). Since rCBF was unchanged, this indicates a dilation of the MCA. hαCGRP induced a decrease in MAP (12%) (P < 0.005) and an increase in heart rate (58%) (P < 0.0001). CGRP dilates cerebral arteries, but the effect is so small that it is unlikely to be the only mechanism of CGRP-induced migraine

Calcitonin gene-related peptide (CGRP) and its receptor components in human and rat spinal trigeminal nucleus and spinal cord at C1-level

<p>Abstract</p> <p>Background</p> <p>Calcitonin gene-related peptide (CGRP) has a key role in migraine pathophysiology and is associated with activation of the trigeminovascular system. The trigeminal ganglion, storing CGRP and its receptor components, projects peripheral to the intracranial vasculature and central to regions in the brainstem with Aδ- and C-fibers; this constitutes an essential part of the pain pathways activated in migraine attacks. Therefore it is of importance to identify the regions within the brainstem that processes nociceptive information from the trigeminovascular system, such as the spinal trigeminal nucleus (STN) and the C1-level of the spinal cord. Immunohistochemistry was used to study the distribution and relation between CGRP and its receptor components - calcitonin receptor-like receptor (CLR) and receptor activity modifying protein 1 (RAMP1) - in human and rat STN and at the C1-level, using a set of newly well characterized antibodies. In addition, double-stainings with CGRP and myelin basic protein (MBP, myelin), synaptophysin (synaptic vesicles) or IB4 (C-fibers in general) were performed.</p> <p>Results</p> <p>In the STN, the highest density of CGRP immunoreactive fibers were found in a network around fiber bundles in the superficial laminae. CLR and RAMP1 expression were predominately found in fibers in the spinal trigeminal tract region, with some fibers spanning into the superficial laminae. Co-localization between CGRP and its receptor components was not noted. In C1, CGRP was expressed in fibers of laminae I and II. The CGRP staining was similar in rat, except for CGRP positive neurons that were found close to the central canal. In C1, the receptor components were detected in laminae I and II, however these fibers were distinct from fibers expressing CGRP as verified by confocal microscopy.</p> <p>Conclusions</p> <p>This study demonstrates the detailed expression of CGRP and its receptor components within STN in the brainstem and in the spinal cord at C1-level, and shows the possibility of CGRP acting postjunctionally in these areas putatively involved in primary headaches.</p

Circulating antimullerian hormone and steroid hormone levels remain high in pregnant women with polycystic ovary syndrome at term

Objective: To investigate plasma antimullerian hormone (AMH) concentration and its relation to steroid hormone levels in pregnant women with polycystic ovary syndrome (PCOS) and controls at term. Design: Case-control study. Setting: University-affiliated hospital. Patient(s): A total of 74 pregnant women at term: 25 women with PCOS (aged 31.6 +/- 3.9 years [mean +/- standard deviation], body mass index 24.0 +/- 3.9 kg/m2, mean gestational length 279 +/- 9 days) and 49 controls (aged 31.7 +/- 3.3 years, body mass index 24.0 +/- 3.3 kg/m2, mean gestational length 281 +/- 9 days). Intervention(s): None. Main Outcome Measure(s): Plasma AMH and steroid hormone levels. Result(s): Antimullerian hormone, T, and androstenedione levels were higher in women with PCOS at term compared with controls, whereas estrogen and P levels were similar. The differences were pronounced in women carrying a female fetus. Testosterone and AMH levels correlated positively in both groups, but E2 levels only in women with PCOS. Conclusion(s): Pregnant women with PCOS present with elevated AMH and androgen levels even at term, suggesting a hormonal imbalance during PCOS pregnancy. Differences were detected especially in pregnancies with a female fetus, raising the question of whether female pregnancies are more susceptible to AMH and steroid hormone actions. (C) Copyright (C) 2018 The Authors. Published by Elsevier Inc. on behalf of the American Society for Reproductive Medicine. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).Peer reviewe

Towards a Sustainable Governance of Information Systems: Devising a Maturity Assessment Tool of Eco-Responsibility Inspired by the Balanced Scorecard

Part 3: Section 2: Sustainable and Responsible InnovationInternational audienceThe assessment of the maturity of Information System (IS) regarding its contribution to corporate social responsibility policy is considered as a stake for organizations. However, few research efforts have been dedicated to this evaluation and even less to the elaboration of a management tool. This paper adopts an engineering perspective to develop a performance assessment approach in this field. Theoretically, this communication (1) mobilizes the methodology of engineering research to build a measurement system of the IS maturity in relation to the economic, social and environmental performance, (2) extends the researches about the sustainable balanced scorecard (SBSC) to the field of IS governance. Practically, this study provides organizations with a global approach to this complex phenomenon as well as a guide to assess it. The originality of this research lies in the application of the conceptual framework of the SBSC to a new research domain

On intellectual capital efficiency and shariah governance in Islamic banking business model

This paper empirically investigates whether intellectual capital (IC) and shariah governance jointly affect the economic performance of Islamic banks (IBs). In contrast to prior research, this paper disaggregate IC and corporate governance features and examine whether the two are jointly related to economic performance. These relationships are further explored before, during and after the financial crisis based on a sample of 64 Islamic banks operating in different regions during the period 2007–2014. The required data to calculate different constituents of IC efficiency and governance mechanism is hand collected from 512 annual reports. After controlling for other corporate governance and bank‐specific characteristics (operational type, bank size, listing status, risk, type of auditor, accounting standard and region), we find both intellectual capital efficiency and shariah governance proxies (size and dominance of prominent scholars of shariah supervisory board) to have a significant positive relationship with accounting measure of performance. However, based on market performance measure, only one proxy for shariah governance mechanism, that is, prominent scholars on SSB, is found to be significant but in the negative direction. These results provide important insights into the relationship between IC efficiency, corporate governance and performance in Islamic banking business model and have policy and practical implications