Signalling mechanisms in the cardiovascular protective effects of estrogen: With a focus on rapid/membrane signalling.

In modern society, cardiovascular disease remains the biggest single threat to life, being responsible for approximately one third of worldwide deaths. Male prevalence is significantly higher than that of women until after menopause, when the prevalence of CVD increases in females until it eventually exceeds that of men. Because of the coincidence of CVD prevalence increasing after menopause, the role of estrogen in the cardiovascular system has been intensively researched during the past two decades , and in observational studies.

NADPH oxidase in the vasculature: Expression, regulation and signalling pathways; role in normal cardiovascular physiology and its dysregulation in hypertension.

The last 20-25 years have seen an explosion of interest in the role of NADPH oxidase (NOX) in cardiovascular function and disease. In vascular smooth muscle and endothelium, NOX generates reactive oxygen species (ROS) that act as second messengers, contributing to the control of normal vascular function. NOX activity is altered in response to a variety of stimuli, including G-protein coupled receptor agonists, growth-factors, perfusion pressure, flow and hypoxia.

Transforming growth factor-β enhances Rho-kinase activity and contraction in airway smooth muscle via the nucleotide exchange factor ARHGEF1.

Key Points: Transforming growth-factor-β (TGF-β) and RhoA/Rho-kinase are independently implicated in the airway hyper-responsiveness associated with asthma, but how these proteins interact is not fully understood. We examined the effects of pre-treatment with TGF-β on expression and activity of RhoA, Rho-kinase and ARHGEF1, an activator of RhoA, as well as on bradykinin-induced contraction, in airway smooth muscle. TGF-β enhanced bradykinin-induced RhoA translocation, Rho-kinase-dependent phosphorylation and contraction, but partially suppressed bradykinin-induced RhoA activity (RhoA-GTP content).

ROS-dependent activation of RhoA/Rho-kinase in pulmonary artery: Role of Src-family kinases and ARHGEF1.

The role of reactive oxygen species (ROS) in smooth muscle contraction is poorly understood. We hypothesised that G-protein coupled receptor (GPCR) activation and hypoxia induce Rho-kinase activity and contraction in rat intra-pulmonary artery (IPA) via stimulation of ROS production and subsequent Src-family kinase (SrcFK) activation. The T-type prostanoid receptor agonist U46619 induced ROS production in pulmonary artery smooth muscle cells (PASMC).

Divergent modulation of Rho-kinase and Ca(2+) influx pathways by Src family kinases and focal adhesion kinase in airway smooth muscle.

Background And Purpose: The importance of tyrosine kinases in airway smooth muscle (ASM) contraction is not fully understood. The aim of this study was to investigate the role of Src-family kinases (SrcFK) and focal adhesion kinase (FAK) in GPCR-mediated ASM contraction and associated signalling events.

Experimental Approach: Contraction was recorded in intact or α-toxin permeabilized rat bronchioles.

Sphingosylphosphorylcholine potentiates vasoreactivity and voltage-gated Ca2+ entry via NOX1 and reactive oxygen species.

Aims: Sphingosylphosphorylcholine (SPC) elicits vasoconstriction at micromolar concentrations. At lower concentrations (≤1 µmol/L), however, it does not constrict intrapulmonary arteries (IPAs), but strongly potentiates vasoreactivity. Our aim was to determine whether this also occurs in a systemic artery and to delineate the signalling pathway.

Control of vascular smooth muscle function by Src-family kinases and reactive oxygen species in health and disease.

Reactive oxygen species (ROS) are now recognised as second messenger molecules that regulate cellular function by reversibly oxidising specific amino acid residues of key target proteins. Amongst these are the Src-family kinases (SrcFKs), a multi-functional group of non-receptor tyrosine kinases highly expressed in vascular smooth muscle (VSM). In this review we examine the evidence supporting a role for ROS-induced SrcFK activity in normal VSM contractile function and in vascular remodelling in cardiovascular disease.

Redox regulation of protein kinases as a modulator of vascular function.

Reactive oxygen species (ROS) are continuously generated in vascular tissues by various oxidoreductase enzymes. They contribute to normal cell signaling, and modulate vascular smooth muscle tone and endothelial permeability in response to physiological agonists and to various cellular stresses and environmental factors, such as hypoxia. While concentrations of ROS are normally tightly controlled by cellular redox buffer systems, if produced in excess they may contribute to vascular disease.

Superoxide differentially controls pulmonary and systemic vascular tone through multiple signalling pathways.

Aims: the aim of this study was to determine the relative importance of Ca(2+) sensitization, ion channels, and intracellular Ca(2+) ([Ca(2+)](i)) in the mixed constrictor/relaxation actions of superoxide anion on systemic and pulmonary arteries.

Methods And Results: pulmonary and mesenteric arteries were obtained from rat. Superoxide was generated in arteries and cells with 6-anilino-5,8-quinolinequinone (LY83583).

Superoxide constricts rat pulmonary arteries via Rho-kinase-mediated Ca(2+) sensitization.

Reactive oxygen species play a key role in vascular disease, pulmonary hypertension, and hypoxic pulmonary vasoconstriction. We investigated contractile responses, intracellular Ca(2+) ([Ca(2+)](i)), Rho-kinase translocation, and phosphorylation of the regulatory subunit of myosin phosphatase (MYPT-1) and of myosin light chain (MLC(20)) in response to LY83583, a generator of superoxide anion, in small intrapulmonary arteries (IPA) of rat. LY83583 caused concentration-dependent constrictions in IPA and greatly enhanced submaximal PGF(2alpha)-mediated preconstriction.

Role of src-family kinases in hypoxic vasoconstriction of rat pulmonary artery.

Aims: We investigated the role of src-family kinases (srcFKs) in hypoxic pulmonary vasoconstriction (HPV) and how this relates to Rho-kinase-mediated Ca(2+) sensitization and changes in intracellular Ca(2+) concentration ([Ca(2+)](i)).

Methods And Results: Intra-pulmonary arteries (IPAs) were obtained from male Wistar rats. HPV was induced in myograph-mounted IPAs.

Low concentrations of sphingosylphosphorylcholine enhance pulmonary artery vasoreactivity: the role of protein kinase C delta and Ca2+ entry.

Sphingosylphosphorylcholine (SPC) is a powerful vasoconstrictor, but in vitro its EC(50) is approximately 100-fold more than plasma concentrations. We examined whether subcontractile concentrations of SPC ( View Article and Find Full Text PDF

Interaction between src family kinases and rho-kinase in agonist-induced Ca2+-sensitization of rat pulmonary artery.

Aims: We investigated the role of src family kinases (srcFK) in agonist-mediated Ca2+-sensitization in pulmonary artery and whether this involves interaction with the rho/rho-kinase pathway.

Methods And Results: Intra-pulmonary arteries (IPAs) and cultured pulmonary artery smooth muscle cells (PASMC) were obtained from rat. Expression of srcFK was determined at the mRNA and protein levels.

Effect of ceramide on the contractility of pregnant rat uterus.

Ceramide and other sphingolipid mediators have emerged as a novel class of lipid second messengers in cell signaling. We assessed the effect of C(2)-ceramide (a membrane permeable analog of ceramide) on spontaneous and agonist-induced contractile responses of uterus, isolated from 19-day pregnant rats. Ceramide (3, 10 microM) moderately, but significantly inhibited the amplitude of spontaneous rhythmic contractions.

Dietary soy modulates endothelium-dependent relaxation in aged male rats: Increased agonist-induced endothelium-derived hyperpolarising factor and basal nitric oxide activity.

We examined the effects of dietary soy on the contributions of endothelium-derived hyperpolarising factor (EDHF), nitric oxide (NO), and oxidative stress to vascular tone in isolated aortic rings and small mesenteric and pulmonary arteries in vitro. Male Wistar rats were either continuously fed a soy-deficient diet (SD) or switched from a soy-deficient diet to a soy-rich one for 6 months (SW). Contractile responses were generally smaller in arteries from SW rats.

Dietary soy isoflavone induced increases in antioxidant and eNOS gene expression lead to improved endothelial function and reduced blood pressure in vivo.

Epidemiological evidence suggests that populations consuming large amounts of soy protein have a reduced incidence of coronary heart disease (1-5). The cardiovascular risks associated with conventional hormone replacement therapy in postmenopausal women (5-7) have precipitated a search for alternative estrogen receptor modulators. Here we report that long-term feeding of rats with a soy protein-rich (SP) diet during gestation and adult life results in decreased oxidative stress, improved endothelial function, and reduced blood pressure in vivo measured by radiotelemetry in aged male offspring.

Modulation of PGF2alpha- and hypoxia-induced contraction of rat intrapulmonary artery by p38 MAPK inhibition: a nitric oxide-dependent mechanism.

The mechanisms through which p38 mitogen-activated protein kinase (p38 MAPK) is involved in smooth muscle contraction remain largely unresolved. We examined the role of p38 MAPK in prostaglandin F(2alpha) (PGF(2alpha))-induced vasoconstriction and in hypoxic pulmonary vasoconstriction (HPV) of rat small intrapulmonary arteries (IPA). The p38 MAPK inhibitors SB-203580 and SB-202190 strongly inhibited PGF(2alpha)-induced vasoconstriction, with IC(50)s of 1.

Euhydric hypercapnia increases vasoreactivity of rat pulmonary arteries via HCO3- transport and depolarisation.

Objective: To examine whether altered PCO2 or HCO3- at normal pH potentiate agonist-induced vasoconstriction of small pulmonary arteries, and if so to determine the mechanism.

Methods: Small intrapulmonary arteries (IPA) from rats were mounted on a myograph and PGF2alpha (3 microM)-induced tension recorded before and 40 min after replacing normal bath solution (5% CO2, 24 mM [HCO3-], pH 7.4) with one containing either normal [HCO3-] (24 mM) gassed with 10% CO2 (pH 7.

Protein kinases in vascular smooth muscle tone--role in the pulmonary vasculature and hypoxic pulmonary vasoconstriction.

Hypoxic pulmonary vasoconstriction (HPV) is an adaptive mechanism that in the normal animal diverts blood away from poorly ventilated areas of the lung, thereby maintaining optimal ventilation-perfusion matching. In global hypoxia however, such as in respiratory disease or at altitude, it causes detrimental increases in pulmonary vascular resistance and pulmonary artery (PA) pressure. The precise intracellular pathways and mechanisms underlying HPV remain unclear, although it is now recognised that both an elevation in smooth muscle intracellular [Ca2+] and a concomitant increase in Ca2+ sensitivity are involved.