Protease-Activated Receptor 2 Controls Vascular Smooth Muscle Cell Proliferation in Cyclic AMP-Dependent Protein Kinase/Mitogen-Activated Protein Kinase Kinase 1/2-Dependent Manner.

INTRODUCTION: Cardiovascular disorders are characterized by vascular smooth muscle (VSM) transition from a contractile to proliferative state. Protease-activated receptor 2 (PAR2) involvement in this phenotypic conversion remains unclear. We hypothesized that PAR2 controls VSM cell proliferation in phenotype-dependent manner and through specific protein kinases. METHODS: Rat clonal low (PLo; P3-P6) and high passage (PHi; P10-P15) VSM cells were established as respective models of quiescent and proliferative cells, based on reduced PKG-1 and VASP. Western blotting determined expression of cytoskeletal/contractile proteins, PAR2, and select protein kinases. DNA synthesis and cell proliferation were measured 24-72 h following PAR2 agonism (SLIGRL; 100 nM-10 µm) with/without PKA (PKI; 10 µm), MEK1/2 (PD98059; 10 µm), and PI3K (LY294002; 1 µm) blockade. RESULTS: PKG-1, VASP, SM22α, calponin, cofilin, and PAR2 were reduced in PHi versus PLo cells. Following PAR2 agonism, DNA synthesis and cell proliferation increased in PLo cells but decreased in PHi cells. Western analyses showed reduced PKA, MEK1/2, and PI3K in PHi versus PLo cells, and kinase blockade revealed PAR2 controls VSM cell proliferation through PKA/MEK1/2. DISCUSSION: Findings highlight PAR2 and PAR2-driven PKA/MEK1/2 in control of VSM cell growth and provide evidence for continued investigation of PAR2 in VSM pathology.

FoxO3 normalizes Smad3-induced arterial smooth muscle cell growth.

Transition of arterial smooth muscle (ASM) from a quiescent, contractile state to a growth-promoting state is a hallmark of cardiovascular disease (CVD), a leading cause of death and disability in the United States and worldwide. While many individual signals have been identified as important mechanisms in this phenotypic conversion, the combined impact of the transcription factors Smad3 and FoxO3 in ASM growth is not known. The purpose of this study was to determine that a coordinated, phosphorylation-specific relationship exists between Smad3 and FoxO3 in the control of ASM cell growth. Using a rat in vivo arterial injury model and rat primary ASM cell lysates and fractions, validated low and high serum in vitro models of respective quiescent and growth states, and adenoviral (Ad-) gene delivery for overexpression (OE) of individual and combined Smad3 and/or FoxO3, we hypothesized that FoxO3 can moderate Smad3-induced ASM cell growth. Key findings revealed unique cellular distribution of Smad3 and FoxO3 under growth conditions, with induction of both nuclear and cytosolic Smad3 yet primarily cytosolic FoxO3; Ad-Smad3 OE leading to cytosolic and nuclear expression of phosphorylated and total Smad3, with almost complete reversal of each with Ad-FoxO3 co-infection in quiescent and growth conditions; Ad-FoxO3 OE leading to enhanced cytosolic expression of phosphorylated and total FoxO3, both reduced with Ad-Smad3 co-infection in quiescent and growth conditions; Ad-FoxO3 inducing expression and activity of the ubiquitin ligase MuRF-1, which was reversed with concomitant Ad-Smad3 OE; and combined Smad3/FoxO3 OE reversing both the pro-growth impact of singular Smad3 and the cytostatic impact of singular FoxO3. A primary takeaway from these observations is the capacity of FoxO3 to reverse growth-promoting effects of Smad3 in ASM cells. Additional findings lend support for reciprocal antagonism of Smad3 on FoxO3-induced cytostasis, and these effects are dependent upon discrete phosphorylation states and cellular localization and involve MuRF-1 in the control of ASM cell growth. Lastly, results showing capacity of FoxO3 to normalize Smad3-induced ASM cell growth largely support our hypothesis, and overall findings provide evidence for utility of Smad3 and/or FoxO3 as potential therapeutic targets against abnormal ASM growth in the context of CVD.

Renal NOXA1/NOX1 Signaling Regulates Epithelial Sodium Channel and Sodium Retention in Angiotensin II-induced Hypertension.

Aims: NADPH oxidase (NOX)-derived reactive oxygen species (ROS) are implicated in the pathophysiology of hypertension in chronic kidney disease patients. Genetic deletion of NOX activator 1 (Noxa1) subunit of NOX1 decreases ROS under pathophysiological conditions. Here, we investigated the role of NOXA1-dependent NOX1 activity in the pathogenesis of angiotensin II (Ang II)-induced hypertension (AIH) and possible involvement of abnormal renal function. Results: NOXA1 is present in epithelial cells of Henle's thick ascending limb and distal nephron. Telemetry showed lower basal systolic blood pressure (BP) in Noxa1-/-versus wild-type mice. Ang II infusion for 1 and 14 days increased NOXA1/NOX1 expression and ROS in kidney of male but not female wild-type mice. Mean BP increased 30 mmHg in wild-type males, with smaller increases in Noxa1-deficient males and wild-type or Noxa1-/- females. In response to an acute salt load, Na+ excretion was similar in wild-type and Noxa1-/- mice before and 14 days after Ang II infusion. However, Na+ excretion was delayed after 1-2 days of Ang II in male wild-type versus Noxa1-/- mice. Ang II increased epithelial Na+ channel (ENaC) levels and activation in the collecting duct principal epithelial cells of wild-type but not Noxa1-/- mice. Aldosterone induced ROS levels and Noxa1 and Scnn1a expression and ENaC activity in a mouse renal epithelial cell line, responses abolished by Noxa1 small-interfering RNA. Innovation and Conclusion: Ang II activation of renal NOXA1/NOX1-dependent ROS enhances tubular ENaC expression and Na+ reabsorption, leading to increased BP. Attenuation of AIH in females is attributed to weaker NOXA1/NOX1-dependent ROS signaling and efficient natriuresis. Antioxid. Redox Signal. 36, 550-566.

Cyclic Nucleotide-Directed Protein Kinases in Cardiovascular Inflammation and Growth.

Cardiovascular disease (CVD), including myocardial infarction (MI) and peripheral or coronary artery disease (PAD, CAD), remains the number one killer of individuals in the United States and worldwide, accounting for nearly 18 million (>30%) global deaths annually. Despite considerable basic science and clinical investigation aimed at identifying key etiologic components of and potential therapeutic targets for CVD, the number of individuals afflicted with these dreaded diseases continues to rise. Of the many biochemical, molecular, and cellular elements and processes characterized to date that have potential to control foundational facets of CVD, the multifaceted cyclic nucleotide pathways continue to be of primary basic science and clinical interest. Cyclic adenosine monophosphate (cyclic AMP) and cyclic guanosine monophosphate (cyclic GMP) and their plethora of downstream protein kinase effectors serve ubiquitous roles not only in cardiovascular homeostasis but also in the pathogenesis of CVD. Already a major target for clinical pharmacotherapy for CVD as well as other pathologies, novel and potentially clinically appealing actions of cyclic nucleotides and their downstream targets are still being discovered. With this in mind, this review article focuses on our current state of knowledge of the cyclic nucleotide-driven serine (Ser)/threonine (Thr) protein kinases in CVD with particular emphasis on cyclic AMP-dependent protein kinase (PKA) and cyclic GMP-dependent protein kinase (PKG). Attention is given to the regulatory interactions of these kinases with inflammatory components including interleukin 6 signals, with G protein-coupled receptor and growth factor signals, and with growth and synthetic transcriptional platforms underlying CVD pathogenesis. This article concludes with a brief discussion of potential future directions and highlights the importance for continued basic science and clinical study of cyclic nucleotide-directed protein kinases as emerging and crucial controllers of cardiac and vascular disease pathologies.

Ultrafine Particulate Matter Increases Cardiac Ischemia/Reperfusion Injury via Mitochondrial Permeability Transition Pore.

Ultrafine particulate matter (UFP) has been associated with increased cardiovascular morbidity and mortality. However, the mechanisms that drive PM-associated cardiovascular disease and dysfunction remain unclear. We examined the impact of oropharyngeal aspiration of 100 µg UFP from the Chapel Hill, NC, air shed in Sprague-Dawley rats on cardiac function, arrhythmogenesis, and cardiac ischemia/reperfusion (I/R) injury using a Langendorff working heart model. We found that exposure to UFP was capable of significantly exacerbating cardiac I/R injury without changing overall cardiac function or major changes in arrhythmogenesis. Cardiac I/R injury was attenuable with administration of cyclosporin A (CsA), suggesting a role for the mitochondrial permeability transition pore (mPTP) in UFP-associated cardiovascular toxicity. Isolated cardiac mitochondria displayed decreased Ca2+ buffering before opening of the mPTP. These findings suggest that UFP-induced expansion of cardiac I/R injury may be a result of mPTP Ca2+ sensitization resulting in increased mitochondrial permeability transition and potential initiation of mPTP-associated cell death pathways.

Disposition of intravenously or orally administered silver nanoparticles in pregnant rats and the effect on the biochemical profile in urine.

Few investigations have been conducted on the disposition and fate of silver nanoparticles (AgNP) in pregnancy. The distribution of a single dose of polyvinylpyrrolidone (PVP)-stabilized AgNP was investigated in pregnant rats. Two sizes of AgNP, 20 and 110 nm, and silver acetate (AgAc) were used to investigate the role of AgNP diameter and particle dissolution in tissue distribution, internal dose and persistence. Dams were administered AgNP or AgAc intravenously (i.v.) (1 mg kg-1 ) or by gavage (p.o.) (10 mg kg-1 ), or vehicle alone, on gestation day 18 and euthanized at 24 or 48 h post-exposure. The silver concentration in tissues was measured using inductively-coupled plasma mass spectrometry. The distribution of silver in dams was influenced by route of administration and AgNP size. The highest concentration of silver (µg Ag g-1 tissue) at 48 h was found in the spleen for i.v. administered AgNP, and in the lungs for AgAc. At 48 h after p.o. administration of AgNP, the highest concentration was measured in the cecum and large intestine, and for AgAc in the placenta. Silver was detected in placenta and fetuses for all groups. Markers of cardiovascular injury, oxidative stress marker, cytokines and chemokines were not significantly elevated in exposed dams compared to vehicle-dosed control. NMR metabolomics analysis of urine indicated that AgNP and AgAc exposure impact the carbohydrate, and amino acid metabolism. This study demonstrates that silver crosses the placenta and is transferred to the fetus regardless of the form of silver. Copyright © 2016 John Wiley & Sons, Ltd.

Impact of pulmonary exposure to gold core silver nanoparticles of different size and capping agents on cardiovascular injury.

BACKGROUND: The uses of engineered nanomaterials have expanded in biomedical technology and consumer manufacturing. Furthermore, pulmonary exposure to various engineered nanomaterials has, likewise, demonstrated the ability to exacerbate cardiac ischemia reperfusion (I/R) injury. However, the influence of particle size or capping agent remains unclear. In an effort to address these influences we explored response to 2 different size gold core nanosilver particles (AgNP) with two different capping agents at 2 different time points. We hypothesized that a pulmonary exposure to AgNP induces cardiovascular toxicity influenced by inflammation and vascular dysfunction resulting in expansion of cardiac I/R Injury that is sensitive to particle size and the capping agent. METHODS: Male Sprague-Dawley rats were exposed to 200 µg of 20 or 110 nm polyvinylprryolidone (PVP) or citrate capped AgNP. One and 7 days following intratracheal instillation serum was analyzed for concentrations of selected cytokines; cardiac I/R injury and isolated coronary artery and aorta segment were assessed for constrictor responses and endothelial dependent relaxation and endothelial independent nitric oxide dependent relaxation. RESULTS: AgNP instillation resulted in modest increase in selected serum cytokines with elevations in IL-2, IL-18, and IL-6. Instillation resulted in a derangement of vascular responses to constrictors serotonin or phenylephrine, as well as endothelial dependent relaxations with acetylcholine or endothelial independent relaxations by sodium nitroprusside in a capping and size dependent manner. Exposure to both 20 and 110 nm AgNP resulted in exacerbation cardiac I/R injury 1 day following IT instillation independent of capping agent with 20 nm AgNP inducing marginally greater injury. Seven days following IT instillation the expansion of I/R injury persisted but the greatest injury was associated with exposure to 110 nm PVP capped AgNP resulted in nearly a two-fold larger infarct size compared to naïve. CONCLUSIONS: Exposure to AgNP may result in vascular dysfunction, a potentially maladaptive sensitization of the immune system to respond to a secondary insult (e.g., cardiac I/R) which may drive expansion of I/R injury at 1 and 7 days following IT instillation where the extent of injury could be correlated with capping agents and AgNP size.

Pulmonary instillation of MWCNT increases lung permeability, decreases gp130 expression in the lungs, and initiates cardiovascular IL-6 transsignaling.

Pulmonary instillation of multiwalled carbon nanotubes (MWCNT) has the potential to promote cardiovascular derangements, but the mechanisms responsible are currently unclear. We hypothesized that exposure to MWCNT would result in increased epithelial barrier permeability by 24 h postexposure and initiate a signaling process involving IL-6/gp130 transsignaling in peripheral vascular tissue. To test this hypothesis we assessed the impact of 1 and 10 µg/cm(2) MWCNT on transepithelial electrical resistance (TEER) and expression of barrier proteins and cell activation in vitro using normal human bronchial epithelial primary cells. Parallel studies using male Sprague-Dawley rats instilled with 100 µg MWCNT measured bronchoalveolar lavage (BAL) differential cell counts, BAL fluid total protein, and lung water-to-tissue weight ratios 24 h postexposure and quantified serum concentrations of IL-6, soluble IL-6r, and soluble gp130. Aortic sections were examined immunohistochemically for gp130 expression, and gp130 mRNA/protein expression was evaluated in rat lung, heart, and aortic tissue homogenates. Our in vitro findings indicate that 10 µg/cm(2) MWCNT decreased the development of TEER and zonula occludens-1 expression relative to the vehicle. In rats MWCNT instillation increased BAL protein, lung water, and induced pulmonary eosinophilia. Serum concentrations of soluble gp130 decreased, aortic endothelial expression of gp130 increased, and expression of gp130 in the lung was downregulated in the MWCNT-exposed group. We propose that pulmonary exposure to MWCNT can manifest as a reduced epithelial barrier and activator of vascular gp130-associated transsignaling that may promote susceptibility to cardiovascular derangements.

Distribution and biomarker of carbon-14 labeled fullerene C60 ([(14) C(U)]C60 ) in pregnant and lactating rats and their offspring after maternal intravenous exposure.

A comprehensive distribution study was conducted in pregnant and lactating rats exposed to a suspension of uniformly carbon-14 labeled C60 ([(14) C(U)]C60 ). Rats were administered [(14) C(U)]C60 (~0.2 mg [(14) C(U)]C60 kg(-1) body weight) or 5% polyvinylpyrrolidone (PVP)-saline vehicle via a single tail vein injection. Pregnant rats were injected on gestation day (GD) 11 (terminated with fetuses after either 24 h or 8 days), GD15 (terminated after 24 h or 4 days), or GD18 (terminated after 24 h). Lactating rats were injected on postnatal day 8 and terminated after 24 h, 3 or 11 days. The distribution of radioactivity in pregnant dams was influenced by both the state of pregnancy and time of termination after exposure. The percentage of recovered radioactivity in pregnant and lactating rats was highest in the liver and lungs. Radioactivity was quantitated in over 20 tissues. Radioactivity was found in the placenta and in fetuses of pregnant dams, and in the milk of lactating rats and in pups. Elimination of radioactivity was < 2% in urine and feces at each time point. Radioactivity remained in blood circulation up to 11 days after [(14) C(U)]C60 exposure. Biomarkers of inflammation, cardiovascular injury and oxidative stress were measured to study the biological impacts of [(14) C(U)]C60 exposure. Oxidative stress was elevated in female pups of exposed dams. Metabolomics analysis of urine showed that [(14) C(U)]C60 exposure to pregnant rats impacted the pathways of vitamin B, regulation of lipid and sugar metabolism and aminoacyl-tRNA biosynthesis. This study demonstrated that [(14) C(U)]C60 crosses the placenta at all stages of pregnancy examined, and is transferred to pups via milk.

Distribution and biomarkers of carbon-14-labeled fullerene C60 ([(14) C(U)]C60 ) in female rats and mice for up to 30 days after intravenous exposure.

A comprehensive distribution study was conducted in female rats and mice exposed to a suspension of uniformly carbon-14-labeled C60 ([(14) C(U)]C60 ). Rodents were administered [(14) C(U)]C60 (~0.9 mg kg(-1) body weight) or 5% polyvinylpyrrolidone-saline vehicle alone via a single tail vein injection. Tissues were collected at 1 h and 1, 7, 14 and 30 days after administration. A separate group of rodents received five daily injections of suspensions of either [(14) C(U)]C60 or vehicle with tissue collection 14 days post exposure. Radioactivity was detected in over 20 tissues at all time points. The highest concentration of radioactivity in rodents at each time point was in liver, lungs and spleen. Elimination of [(14) C(U)]C60 was < 2% in urine and feces at any 24 h time points. [(14) C(U)]C60 and [(14) C(U)]C60 -retinol were detected in liver of rats and together accounted for ~99% and ~56% of the total recovered at 1 and 30 days postexposure, respectively. The blood radioactivity at 1 h after [(14) C(U)]C60 exposure was fourfold higher in rats than in mice; blood radioactivity was still in circulation at 30 days post [(14) C(U)]C60 exposure in both species (<1%). Levels of oxidative stress markers increased by 5 days after exposure and remained elevated, while levels of inflammation markers initially increased and then returned to control values. The level of cardiovascular marker von Willebrand factor, increased in rats, but remained at control levels in mice. This study demonstrates that [(14) C(U)]C60 is retained in female rodents with little elimination by 30 days after i.v. exposure, and leads to systemic oxidative stress.

PVP formulated fullerene (C60) increases Rho-kinase dependent vascular tissue contractility in pregnant Sprague Dawley rats.

Pregnancy is a unique physiological state, in which C60 fullerene is reported to be distributed in both maternal and fetal tissues. Tissue distribution of C60 differs between pregnant and non-pregnant states, presumably due to functional changes in vasculature during pregnancy. We hypothesized that polyvinylpyrrolidone (PVP) formulated C60 (C60/PVP) increases vascular tissue contractility during pregnancy by increasing Rho-kinase activity. C60/PVP was administered intravenously to pregnant and non-pregnant female Sprague Dawley rats. Vascular responses were assessed using wire myography 24h post-exposure. Increased stress generation was observed in uterine artery, thoracic aorta and umbilical vein. Rho-Rho-kinase mediated force maintenance was increased in arterial segments from C60/PVP exposed pregnant rats when compared to PVP exposed rats. Our findings suggest that intravenous exposure to C60/PVP during pregnancy increases vascular tissue contractility of the uterine artery through elements of Rho-Rho-kinase signaling during late stages of pregnancy.

C60 exposure augments cardiac ischemia/reperfusion injury and coronary artery contraction in Sprague Dawley rats.

The potential uses of engineered C60 fullerene (C60) have expanded in recent decades to include industrial and biomedical applications. Based on clinical findings associated with particulate matter exposure and our data with multi-walled carbon nanotubes, we hypothesized that ischemia/reperfusion (I/R) injury and pharmacological responses in isolated coronary arteries would depend upon the route of exposure and gender in rats instilled with C60. Male and female Sprague Dawley rats were used to test this hypothesis by surgical induction of cardiac I/R injury in situ 24 h after intratracheal (IT) or intravenous (IV) instillation of 28 µg of C60 formulated in polyvinylpyrrolidone (PVP) or PVP vehicle. Serum was collected for quantification of various cytokines. Coronary artery segments were isolated for assessment of vasoactive pharmacology via wire myography. Both IV and IT exposure to C60 resulted in expansion of myocardial infarction in male and female rats following I/R injury. Serum-collected post-I/R showed elevated concentrations of interleukin-6 and monocyte chemotactic protein-1 in male rats exposed to IV C60. Coronary arteries isolated from male rats exposed to IT C60 demonstrated augmented vasocontraction in response to endothelin-1 that was attenuated with Indomethacin. IV C60 exposure resulted in impaired acetylcholine relaxation in male rats and IT C60 exposure resulted in depressed vasorelaxation in response to sodium nitroprusside in female rats. Based on these data, we conclude that IT and IV exposure to C60 results in unique cardiovascular consequences that may favor heightened coronary resistance and myocardial susceptibility to I/R injury.