The Concise Guide to PHARMACOLOGY 2015/16: Other ion channels

The Concise Guide to PHARMACOLOGY 2015/16 provides concise overviews of the key properties of over 1750 human drug targets with their pharmacology, plus links to an open access knowledgebase of drug targets and their ligands (www.guidetopharmacology.org), which provides more detailed views of target and ligand properties. The full contents can be found at http://onlinelibrary.wiley.com/doi/10.1111/bph.13351/full. Other ion channels are one of the eight major pharmacological targets into which the Guide is divided, with the others being: G protein‐coupled receptors, ligand‐gated ion channels, voltage‐gated ion channels, nuclear hormone receptors, catalytic receptors, enzymes and transporters. These are presented with nomenclature guidance and summary information on the best available pharmacological tools, alongside key references and suggestions for further reading. The Concise Guide is published in landscape format in order to facilitate comparison of related targets. It is a condensed version of material contemporary to late 2015, which is presented in greater detail and constantly updated on the website www.guidetopharmacology.org, superseding data presented in the previous Guides to Receptors & Channels and the Concise Guide to PHARMACOLOGY 2013/14. It is produced in conjunction with NC‐IUPHAR and provides the official IUPHAR classification and nomenclature for human drug targets, where appropriate. It consolidates information previously curated and displayed separately in IUPHAR‐DB and GRAC and provides a permanent, citable, point‐in‐time record that will survive database updates.

Conflict of interest

The authors state that there are no conflicts of interest to declare.

Family structure

5943 Aquaporins 5944 Chloride channels 5944 ClC family 5947 CFTR 5948 Calcium activated chloride channel 5949 Maxi chloride channel 5950 Volume regulated chloride channels 5952 Connexins and Pannexins 5954 Sodium leak channel, non‐selective     

Class A1 scavenger receptors in cardiovascular diseases

Class A1 scavenger receptors (SR‐A1) are membrane glycoproteins that can form homotrimers. This receptor was originally defined by its ability to mediate the accumulation of lipids in macrophages. Subsequent studies reveal that SR‐A1 plays critical roles in innate immunity, cell apoptosis and proliferation. This review highlights recent advances in understanding the structure, receptor pathway and regulation of SR‐A1. Although its role in atherosclerosis is disputable, recent discoveries suggest that SR‐A1 function in anti‐inflammatory responses by promoting an M2 macrophage phenotype in cardiovascular diseases. Therefore, SR‐A1 may be a potential target for therapeutic intervention of cardiovascular diseases.

Linked Articles

This article is part of a themed section on Chinese Innovation in Cardiovascular Drug Discovery. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2015.172.issue-23

Abbreviations

acLDL

acetylated low‐density lipoprotein

ER

endoplasmic reticulum

I/R

ischaemia/reperfusion

LTA

lipoteichoic acid

MI

myocardial infarction

mLDL

modified low‐density lipoprotein

oxLDL

oxidized low‐density lipoprotein

PRR

pattern recognition receptor

RAGE

receptor for advanced glycated end‐products

SR‐A1

class A1 scavenger receptor

TLR4

Toll‐like receptor 4

TRAF6

TNF receptor‐associated factor 6

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Activation of M 3 cholinoceptors attenuates vascular injury after ischaemia/reperfusion by inhibiting the Ca 2+/calmodulin‐dependent protein kinase II pathway

Background and Purpose

The activation of M ₃ cholinoceptors (M ₃ receptors) by choline reduces cardiovascular risk, but it is unclear whether these receptors can regulate ischaemia/reperfusion (I/R)‐induced vascular injury. Thus, the primary goal of the present study was to explore the effects of choline on the function of mesenteric arteries following I/R, with a major focus on Ca²⁺/calmodulin‐dependent protein kinase II (CaMKII) regulation.

Experimental Approach

Rats were given choline (10 mg·kg⁻¹, i.v.) and then the superior mesenteric artery was occluded for 60 min (ischaemia), followed by 90 min of reperfusion. The M ₃ receptor antagonist, 4‐diphenylacetoxy‐N‐methylpiperidine methiodide (4‐DAMP), was injected (0.12 μg·kg⁻¹, i.v.) 5 min prior to choline treatment. Vascular function was examined in rings of mesenteric arteries isolated after the reperfusion procedure. Vascular superoxide anion production, CaMKII and the levels of Ca²⁺‐cycling proteins were also assessed.

Key Results

Choline treatment attenuated I/R‐induced vascular dysfunction, blocked elevations in the levels of reactive oxygen species (ROS) and decreased the up‐regulated expression of oxidised CaMKII and phosphorylated CaMKII. In addition, choline reversed the abnormal expression of Ca²⁺‐cycling proteins, including Na⁺/Ca²⁺ exchanger, inositol 1,4,5‐trisphosphate receptor, sarcoplasmic reticulum Ca²⁺‐ATPase and phospholamban. All of these cholinergic effects of choline were abolished by 4‐DAMP.

Conclusions and Implications

Our data suggest that inhibition of the ROS‐mediated CaMKII pathway and modulation of Ca²⁺‐cycling proteins may be novel mechanisms underlying choline‐induced vascular protection. These results represent a significant addition to the understanding of the pharmacological roles of M ₃ receptors in the vasculature, providing a new therapeutic strategy for I/R‐induced vascular injury.

Linked Articles

This article is part of a themed section on Chinese Innovation in Cardiovascular Drug Discovery. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2015.172.issue-23

Abbreviations

4‐DAMP

4‐diphenylacetoxy‐N‐methylpiperidine methiodide

CaMKII

Ca²⁺/calmodulin‐dependent protein kinase II

DHE

dihydroethidium

I/R

ischaemia/reperfusion

IP₃R

inositol 1,4,5‐trisphosphate receptor

NAC

N‐acetyl‐L‐cysteine

NCX

Na⁺/Ca²⁺ exchanger

PLB

phospholamban

ROS

reactive oxygen species

SERCA

sarcoplasmic reticulum Ca²⁺‐ATPase

SNP

sodium nitroprusside

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Biased β2‐adrenoceptor signalling in heart failure: pathophysiology and drug discovery

The body is constantly faced with a dynamic requirement for blood flow. The heart is able to respond to these changing needs by adjusting cardiac output based on cues emitted by circulating catecholamine levels. Cardiac β‐adrenoceptors transduce the signal produced by catecholamine stimulation via G_s proteins to their downstream effectors to increase heart contractility. During heart failure, cardiac output is insufficient to meet the needs of the body; catecholamine levels are high and β‐adrenoceptors become hyperstimulated. The hyperstimulated β₁‐adrenoceptors induce a cardiotoxic effect, which could be counteracted by the cardioprotective effect of β₂‐adrenoceptor‐mediated G_i signalling. However, β₂‐adrenoceptor‐G_i signalling negates the stimulatory effect of the G_s signalling on cardiomyocyte contraction and further exacerbates cardiodepression. Here, further to the localization of β₁‐ and β₂‐adrenoceptors and β₂‐adrenoceptor‐mediated β‐arrestin signalling in cardiomyocytes, we discuss features of the dysregulation of β‐adrenoceptor subtype signalling in the failing heart, and conclude that G_i‐biased β₂‐adrenoceptor signalling is a pathogenic pathway in heart failure that plays a crucial role in cardiac remodelling. In contrast, β₂‐adrenoceptor‐G_s signalling increases cardiomyocyte contractility without causing cardiotoxicity. Finally, we discuss a novel therapeutic approach for heart failure using a G_s‐biased β₂‐adrenoceptor agonist and a β₁‐adrenoceptor antagonist in combination. This combination treatment normalizes the β‐adrenoceptor subtype signalling in the failing heart and produces therapeutic effects that outperform traditional heart failure therapies in animal models. The present review illustrates how the concept of biased signalling can be applied to increase our understanding of the pathophysiology of diseases and in the development of novel therapies.

Linked Articles

This article is part of a themed section on Chinese Innovation in Cardiovascular Drug Discovery. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2015.172.issue-23

Abbreviations

ACEI

ACE inhibitors

CaMKII

Ca²⁺/calmodulin‐dependent kinase II

ct

carboxy terminus

EGFR

epidermal growth receptor

Epac

exchange protein directly activated by cAMP

G_i

inhibitory G protein

GRK

GPCR kinase

G_s

stimulatory G protein

HF

heart failure

PKA

cAMP‐dependent protein kinase

SNS

sympathetic nervous system

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Oestrogen inhibits BMP4‐induced BMP4 expression in cardiomyocytes: a potential mechanism of oestrogen‐mediated protection against cardiac hypertrophy

Background and Purpose

Oestrogen inhibits cardiac hypertrophy and bone morphogenetic protein‐4 (BMP4) induces cardiac hypertrophy. Here we have studied the inhibition by oestrogen of BMP4 expression in cardiomyocytes.

Experimental Approach

Cultures of neonatal rat cardiomyocytes were used in in vitro experiments. Bilatαl ovariectomy (OVX) was carried out in female Kunming mice and cardiac hypertrophy was induced by transverse aortic constriction (TAC).

Key Results

Oestrogen inhibited BMP4‐induced cardiomyocyte hypertrophy and BMP4 expression in vitro. The inhibition of BMP4‐induced BMP4 protein expression by oestrogen was prevented by the inhibitor of oestrogen receptor‐β, PHTPP, but not by the inhibitor of oestrogen receptor‐α MPP. BMP4 induced smad1/5/8 activation, which was not affected by oestrogen in cardiomyocytes. BMP4 induced JNK but not ERK1/2 and p38 activation, and activated JNK was inhibited by oestrogen. Treatment with the p38 inhibitor SB203580 or the JNK inhibitor SP600125 inhibited BMP4‐induced BMP4 expression in cardiomyocytes, but the ERK1/2 inhibitor U0126 increased BMP4‐induced BMP4 expression, indicating that JNK, ERK1/2 and p38 MAPKs were all involved, although only JNK activation contributed to the inhibition of BMP4‐induced BMP4 expression by oestrogen. TAC induced significant heart hypertrophy in OVX mice in vivo and oestrogen replacement inhibited TAC‐induced heart hypertrophy in OVX mice. In parallel with the data of heart hypertrophy, oestrogen replacement significantly reduced the increased BMP4 protein expression in TAC‐treated OVX mice.

Conclusions and Implications

Oestrogen treatment inhibited BMP4‐induced BMP4 expression in cardiomyocytes through stimulating oestrogen receptor‐β and inhibiting JNK activation. Our results provide a novel mechanism underlying oestrogen‐mediated protection against cardiac hypertrophy.

Linked Articles

This article is part of a themed section on Chinese Innovation in Cardiovascular Drug Discovery. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2015.172.issue-23

Abbreviations

BMP4

bone morphogenetic protein‐4

ER‐α

oestrogen receptor‐α

ER‐β

oestrogen receptor‐β

MPP

1,3‐bis(4‐hydroxyphenyl)‐4‐methyl‐5‐[4‐(2‐piperidinylethoxy)phenol]‐1H‐pyrazole dihydrochloride

OVX

ovariectomy

PHTPP

4‐(2‐phenyl‐5,7‐bis(trifluoromethyl)pyrazolo[1,5‐a]pyrimidin‐3‐yl)phenol

TAC

transverse aortic constriction

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Progressive inflammation‐mediated neurodegeneration after traumatic brain or spinal cord injury

Traumatic brain injury (TBI) has been linked to dementia and chronic neurodegeneration. Described initially in boxers and currently recognized across high contact sports, the association between repeated concussion (mild TBI) and progressive neuropsychiatric abnormalities has recently received widespread attention, and has been termed chronic traumatic encephalopathy. Less well appreciated are cognitive changes associated with neurodegeneration in the brain after isolated spinal cord injury. Also under‐recognized is the role of sustained neuroinflammation after brain or spinal cord trauma, even though this relationship has been known since the 1950s and is supported by more recent preclinical and clinical studies. These pathological mechanisms, manifested by extensive microglial and astroglial activation and appropriately termed chronic traumatic brain inflammation or chronic traumatic inflammatory encephalopathy, may be among the most important causes of post‐traumatic neurodegeneration in terms of prevalence. Importantly, emerging experimental work demonstrates that persistent neuroinflammation can cause progressive neurodegeneration that may be treatable even weeks after traumatic injury.

Linked Articles

This article is part of a themed section on Inflammation: maladies, models, mechanisms and molecules. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2016.173.issue-4

Abbreviations

AD

Alzheimer''s disease

CCI

controlled cortical impact

CTBI

chronic traumatic brain inflammation

CTE

chronic traumatic encephalopathy

CTIE

chronic traumatic inflammatory encephalopathy

DG

dentate gyrus

ERPs

event‐related potentials

SCI

spinal cord injury

TBI

traumatic brain injury

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Advances in exploring the role of microRNAs in the pathogenesis,diagnosis and therapy of cardiac diseases in China

Cardiovascular disease has become the most serious health threat and represents the major cause of morbidity and mortality in China, as in other industrialized nations. During the past few decades, China''s economic boom has tremendously improved people''s standard of living but has also changed their lifestyle, increasing the prevalence of cardiovascular disease, the so‐called ‘disease of modern civilization’. This new trend has attracted a significant amount of research. Many of the studies conducted by Chinese investigators are orientated towards understanding the molecular mechanisms of cardiovascular disease. At the molecular level, the long‐standing consensus is that cardiovascular disease is associated with a sequence mutation (genetic anomaly) and expression deregulation (epigenetic disorder) of protein‐coding genes. However, new research data have established the non‐protein‐coding genes microRNAs (miRNAs) as a central regulator of the pathogenesis of cardiac disease and a potential new therapeutic target for cardiovascular disease. These small non‐coding RNAs have also been subjected to extensive, rigorous investigations by Chinese researchers. Over the years, a large body of studies on miRNAs in cardiovascular disease has been conducted by Chinese investigators, yielding fruitful research results and a better understanding of miRNAs as a new level of molecular mechanisms for the pathogenesis of cardiac disease. In this review, we briefly summarize the current status of research in the field of miRNAs and cardiovascular disease in China, highlighting the advances made in elucidating the role of miRNAs in various cardiac conditions, including cardiac arrhythmia, myocardial ischaemia, cardiac hypertrophy and heart failure. We have also examined the potential of miRNAs as novel diagnostic biomarkers and therapeutic targets.

Linked Articles

This article is part of a themed section on Chinese Innovation in Cardiovascular Drug Discovery. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2015.172.issue-23

Abbreviations

AF

atrial fibrillation

AMI

acute myocardial infarction

APD

action potential duration

Cx43

connexin 43 (also known as GJA1, gap junction protein, α1)

Drp1

dynamin‐related protein‐1

E‐C

excitation‐contraction

HSP60

heat shock protein 60

I_CaL

L type calcium current

JP2

junctophilin‐2

KCNJ2

gene for potassium inwardly rectifying channel, subfamily J, member 2 also known as K_ir2.1, inwardly rectifying potassium channel 2.1

LNA

locked nucleic acid

MI

myocardial infarct

miRNAs

microRNAs

NFAT

nuclear factor of activated T‐cells

SERCA2a

sarcoplasmic reticulum calcium ATPase

K_Ca2.3 (also known as SK3)

small conductance calcium‐activated potassium channels 3

TGF‐β1

transforming growth factor‐β1

TGFBR2

transforming growth factor‐β receptor II

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A metabolite of Danshen formulae attenuates cardiac fibrosis induced by isoprenaline,via a NOX2/ROS/p38 pathway

Background and Purpose

Cardiac fibrosis is a common feature of advanced coronary heart disease and is characteristic of heart disease. However, currently available drugs against cardiac fibrosis are still very limited. Here, we have assessed the role of isopropyl 3‐(3,4‐dihydroxyphenyl)‐2‐hydroxylpropanoate (IDHP), a new metabolite of Danshen Dripping Pills, in cardiac fibrosis mediated by the β‐adrenoceptor agonist, isoprenaline, and its underlying mechanisms.

Experimental Approach

Identification of IDHP was identified by mass spectrometry, and proton and carbon nuclear magnetic resonance spectra. Myocardial collagen was quantitatively assessed with Picrosirius Red staining. Expression of mRNA for collagen was evaluated with real‐time PCR. Phosphorylated and total p38 MAPK, NADPH oxidase (NOX) and superoxide dismutase (SOD) were analysed by Western blot. Generation of reactive oxygen species (ROS) generation was evaluated by dihydroethidium (DHE) fluorescent staining. NOX2 was knocked down using specific siRNA.

Key Results

IDHP attenuated β‐adrenoceptor mediated cardiac fibrosis in vivo and inhibited isoprenaline‐induced proliferation of neonatal rat cardiac fibroblasts (NRCFs) and collagen I synthesis in vitro. Phosphorylation of p38 MAPK, which is an important mediator in the pathogenesis of isoprenaline‐induced cardiac fibrosis, was inhibited by IDHP. This inhibition of phospho‐p38 by IDHP was dependent on decreased generation of ROS. These effects of IDHP were abolished in NRCFs treated with siRNA for NOX2.

Conclusions and Implications

IDHP attenuated the cardiac fibrosis induced by isoprenaline through a NOX2/ROS/p38 pathway. These novel findings suggest that IDHP is a potential pharmacological candidate for the treatment of cardiac fibrosis, induced by β‐adrenoceptor agonists.

Linked Articles

This article is part of a themed section on Chinese Innovation in Cardiovascular Drug Discovery. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2015.172.issue-23

Abbreviations

CCK‐8

Cell Counting Kit‐8

DHE

dihydroethidium

ECM

extracellular matrix

IDHP

isopropyl 3‐(3,4‐dihydroxyphenyl)‐2‐hydroxylpropanoate

NAC

N‐acetylcysteine

NOX

NADPH oxidase

NRCFs

neonatal rat cardiac fibroblasts

ROS

reactive oxygen species

SOD

superoxide dismutase

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Aldosterone down‐regulates the slowly activated delayed rectifier potassium current in adult guinea pig cardiomyocytes

Background and Purpose

There is emerging evidence that the mineralocorticoid hormone aldosterone is associated with arrhythmias in cardiovascular disease. However, the effect of aldosterone on the slowly activated delayed rectifier potassium current (I_{K s}) remains poorly understood. The present study was designed to investigate the modulation of I_{K s} by aldosterone.

Experimental Approach

Adult guinea pigs were treated with aldosterone for 28 days via osmotic pumps. Standard glass microelectrode recordings and whole‐cell patch‐clamp techniques were used to record action potentials in papillary muscles and I_{K s} in ventricular cardiomyocytes.

Key Results

The aldosterone‐treated animals exhibited a prolongation of the QT interval and action potential duration with a higher incidence of early afterdepolarizations. Patch‐clamp recordings showed a significant down‐regulation of I_{K s} density in the ventricular myocytes of these treated animals. These aldosterone‐induced electrophysiological changes were fully prevented by a combined treatment with spironolactone, a mineralocorticoid receptor (MR) antagonist. In addition, in in vitro cultured ventricular cardiomyocytes, treatment with aldosterone (sustained exposure for 24 h) decreased the I_{K s} density in a concentration‐dependent manner. Furthermore, a significant corresponding reduction in the mRNA/protein expression of IKs channel pore and auxiliary subunits, KCNQ1 and KCNE1 was detected in ventricular tissue from the aldosterone‐treated animals.

Conclusions and Implications

Aldosterone down‐regulates I_{K s} by inhibiting the expression of KCNQ1 and KCNE1, thus delaying the ventricular repolarization. These results provide new insights into the mechanism underlying K ⁺ channel remodelling in heart disease and may explain the highly beneficial effects of MR antagonists in HF.

Linked Articles

This article is part of a themed section on Chinese Innovation in Cardiovascular Drug Discovery. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2015.172.issue-23

Abbreviations

APD

action potential duration

APD₉₀

APD at 90% of repolarization

EAD

early afterdepolarization

ERG

ether‐a‐go‐go related gene

HF

heart failure

HSP90

heat shock protein 90

I_K

delayed rectifier K⁺ current

I_Kr

rapid component of I_K

I_Ks

slow component of I_K

MR

mineralocorticoid receptor

Nim

nimodipine

RAAS

renin‐angiotensin‐aldosterone system

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Different downstream signalling of CCK1 receptors regulates distinct functions of CCK in pancreatic beta cells

Background and Purpose

Cholecystokinin (CCK) is secreted by intestinal I cells and regulates important metabolic functions. In pancreatic islets, CCK controls beta cell functions primarily through CCK₁ receptors, but the signalling pathways downstream of these receptors in pancreatic beta cells are not well defined.

Experimental Approach

Apoptosis in pancreatic beta cell apoptosis was evaluated using Hoechst‐33342 staining, TUNEL assays and Annexin‐V‐FITC/PI staining. Insulin secretion and second messenger production were monitored using ELISAs. Protein and phospho‐protein levels were determined by Western blotting. A glucose tolerance test was carried out to examine the functions of CCK‐8s in streptozotocin‐induced diabetic mice.

Key Results

The sulfated carboxy‐terminal octapeptide CCK_26‐33 amide (CCK‐8s) activated CCK₁ receptors and induced accumulation of both IP₃ and cAMP. Whereas G_q‐PLC‐IP₃ signalling was required for the CCK‐8s‐induced insulin secretion under low‐glucose conditions, G_s‐PKA/Epac signalling contributed more strongly to the CCK‐8s‐mediated insulin secretion in high‐glucose conditions. CCK‐8s also promoted formation of the CCK₁ receptor/β‐arrestin‐1 complex in pancreatic beta cells. Using β‐arrestin‐1 knockout mice, we demonstrated that β‐arrestin‐1 is a key mediator of both CCK‐8s‐mediated insulin secretion and of its the protective effect against apoptosis in pancreatic beta cells. The anti‐apoptotic effects of β‐arrestin‐1 occurred through cytoplasmic late‐phase ERK activation, which activates the 90‐kDa ribosomal S6 kinase‐phospho–Bcl‐2‐family protein pathway.

Conclusions and Implications

Knowledge of different CCK₁ receptor‐activated downstream signalling pathways in the regulation of distinct functions of pancreatic beta cells could be used to identify biased CCK₁ receptor ligands for the development of new anti‐diabetic drugs.

Abbreviations

CCK

cholecystokinin

CCK‐8s

sulfated cholecystokinin fragment 26‐33 amide

p90RSK

90‐kDa ribosomal S6 kinase

siRNA

small interfering RNA

STZ

streptozotocin

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α7 nicotinic ACh receptor‐deficient mice exhibit sustained attention impairments that are reversed by β2 nicotinic ACh receptor activation

Background and Purpose

Disruptions of executive function, including attentional deficits, are a hallmark of a number of diseases. ACh in the prefrontal cortex regulates attentive behaviour; however, the role of α7 nicotinic ACh receptor (α7nAChR) in attention is contentious.

Experimental Approach

In order to probe attention, we trained both wild‐type and α7nAChR knockout mice on a touch screen‐based five‐choice serial reaction time task (5‐CSRT). Following training procedures, we then tested sustained attention using a probe trial experiment. To further differentiate the role of specific nicotinic receptors in attention, we then tested the effects of both α7nAChR and β2nAChR agonists on the performance of both wild‐type and knockout mice on the 5‐CSRT task.

Key Results

At low doses, α7nAChR agonists improved attentional performance of wild‐type mice, while high doses had deleterious effects on attention. α7nAChR knockout mice displayed deficits in sustained attention that were not ameliorated by α7nAChR agonists. However, these deficits were completely reversed by the administration of a β2nAChR agonist. Furthermore, administration of a β2nAChR agonist in α7nAChR knockout mice elicited similar biochemical response in the prefrontal cortex as the administration of α7nAChR agonists in wild‐type mice.

Conclusions and Implications

Our experiments reveal an intricate relationship between distinct nicotinic receptors to regulate attentional performance and provide the basis for targeting β2nAChRs pharmacologically to decrease attentional deficits due to a dysfunction in α7nAChRs.

Abbreviations

5‐CSRT

five‐choice serial reaction time task

VAChT

vesicular ACh transporter

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Aspirin enhances protective effect of fish oil against thrombosis and injury‐induced vascular remodelling

Background and Purpose

Although aspirin (acetylsalicylic acid) is commonly used to prevent ischaemic events in patients with coronary artery disease, many patients fail to respond to aspirin treatment. Dietary fish oil (FO), containing ω3 polyunsaturated fatty acids (PUFAs), has anti‐inflammatory and cardio‐protective properties, such as lowering cholesterol and modulating platelet activity. The objective of the present study was to investigate the potential additional effects of aspirin and FO on platelet activity and vascular response to injury.

Experimental Approach

Femoral arterial remodelling was induced by wire injury in mice. Platelet aggregation, and photochemical‐ and ferric chloride‐induced carotid artery thrombosis were employed to evaluate platelet function.

Key Results

FO treatment increased membrane ω3 PUFA incorporation, lowered plasma triglyceride and cholesterol levels, and reduced systolic BP in mice. FO or aspirin alone inhibited platelet aggregation; however, when combined, they exhibited synergistic suppression of platelet activity in mice, independent of COX‐1 inhibition. FO alone, but not aspirin, attenuated arterial neointimal growth in response to injury. Strikingly, a combination of FO and aspirin synergistically inhibited injury‐induced neointimal hyperplasia and reduced perivascular inflammatory reactions. Moreover, co‐administration of FO and aspirin decreased the expression of pro‐inflammatory cytokines and adhesion molecules in inflammatory cells. Consistently, a pro‐resolution lipid mediator‐Resolvin E1, was significantly elevated in plasma in FO/aspirin‐treated mice.

Conclusions and Implications

Co‐administration of FO and low‐dose aspirin may act synergistically to protect against thrombosis and injury‐induced vascular remodelling in mice. Our results support further investigation of adjuvant FO supplementation for patients with stable coronary artery disease.

Linked Articles

This article is part of a themed section on Chinese Innovation in Cardiovascular Drug Discovery. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2015.172.issue-23

Abbreviations

AA

arachidonic acid

CO

coconut oil

CVD

cardiovascular disease

DHA

docosahexaenoic acid

EPA

eicosapentaenoic acid

FO

fish oil

HDLC

high‐density lipoprotein cholesterol

LDLC

low‐density lipoprotein cholesterol

PCI

percutaneous coronary intervention

PUFA

polyunsaturated fatty acid; TG, triglyceride

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Meningeal blood flow is controlled by H2S‐NO crosstalk activating a HNO‐TRPA1‐CGRP signalling pathway

Background and Purpose

Meningeal blood flow is controlled by CGRP released from trigeminal afferents and NO mainly produced in arterial endothelium. The vasodilator effect of NO may be due to the NO–derived compound, nitroxyl (HNO), generated through reaction with endogenous H₂S. We investigated the involvement of HNO in CGRP release and meningeal blood flow.

Experimental Approach

Blood flow in exposed dura mater of rats was recorded by laser Doppler flowmetry. CGRP release from the dura mater in the hemisected rat head was quantified using an elisa. NO and H₂S were localized histochemically with specific sensors.

Key Results

Topical administration of the NO donor diethylamine‐NONOate increased meningeal blood flow by 30%. Pretreatment with oxamic acid, an inhibitor of H₂S synthesis, reduced this effect. Administration of Na₂S increased blood flow by 20%, an effect abolished by the CGRP receptor antagonist CGRP _8‐37 or the TRPA1 channel antagonist HC030031 and reduced when endogenous NO synthesis was blocked. Na₂S dose‐dependently increased CGRP release two‐ to threefold. Co‐administration of diethylamine‐NONOate facilitated CGRP release, while inhibition of endogenous NO or H₂S synthesis lowered basal CGRP release. NO and H₂S were mainly localized in arterial vessels, HNO additionally in nerve fibre bundles. HNO staining was lost after treatment with L‐NMMA and oxamic acid.

Conclusions and Implications

NO and H₂S cooperatively increased meningeal blood flow by forming HNO, which activated TRPA1 cation channels in trigeminal fibres, inducing CGRP release. This HNO‐TRPA1‐CGRP signalling pathway may be relevant to the pathophysiology of headaches.

Abbreviations

CBS

cystathionine β‐synthase

CSE

cystathionine γ‐lyase

Cy3

cyanine dye 3

DAF

4‐amino‐5‐methylamino‐2′,7′‐difluoresceine diacetate

HNO

nitroxyl

iNOS

inducible NOS

L‐NMMA

L‐NG‐monomethylarginine acetate

MMA

middle meningeal artery

MST

mercaptopyruvate sulfurtransferase

nNOS

neuronal NOS

NONOate

diethylamine‐NONOate, DEANONOate

ODQ

1H‐[1,2,4]oxadiazole[4,3‐a]quinoxalin‐1‐one

sGC

soluble GC

SIF

synthetic interstitial fluid

TRPA1

transient receptor potential ankyrin 1 channel

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Genistein alleviates pressure overload‐induced cardiac dysfunction and interstitial fibrosis in mice

Background and Purpose

Pressure overload‐induced cardiac interstitial fibrosis is viewed as a major cause of heart failure in patients with hypertension or aorta atherosclerosis. The purpose of this study was to investigate the effects and the underlying mechanisms of genistein, a natural phytoestrogen found in soy bean extract, on pressure overload‐induced cardiac fibrosis.

Experimental Approach

Genisten was administered to mice with pressure overload induced by transverse aortic constriction. Eight weeks later, its effects on cardiac dysfunction, hypertrophy and fibrosis were determined. Its effects on proliferation, collagen production and myofibroblast transformation of cardiac fibroblasts (CFs) and the signalling pathways were also assessed in vitro.

Key Results

Pressure overload‐induced cardiac dysfunction, hypertrophy and fibrosis were markedly attenuated by genistein. In cultured CFs, genistein inhibited TGFβ1‐induced proliferation, collagen production and myofibroblast transformation. Genistein suppressed TGFβ‐activated kinase 1 (TAK1) expression and produced anti‐fibrotic effects by blocking the TAK1/MKK4/JNK pathway. Further analysis indicated that it up‐regulated oestrogen‐dependent expression of metastasis‐associated gene 3 (MTA3), which was found to be a negative regulator of TAK1. Silencing MTA3 by siRNA, or inhibiting the activity of the MTA3‐NuRD complex with trichostatin A, abolished genistein''s anti‐fibrotic effects.

Conclusions and Implications

Genistein improved cardiac function and inhibited cardiac fibrosis in response to pressure overload. The underlying mechanism may involve regulation of the MTA3/TAK1/MKK4/JNK signalling pathway. Genistein may have potential as a novel agent for prevention and therapy of cardiac disorders associated with fibrosis.

Linked Articles

This article is part of a themed section on Chinese Innovation in Cardiovascular Drug Discovery. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2015.172.issue-23

Abbreviations

CFs

cardiac fibroblasts

CTGF

connective tissue growth factor

ECM

extracellular matrix

EdU

5‐ethynyl‐2′‐deoxyuridine

EF

ejection fraction

ER

oestrogen receptors

FS

fractional shortening

MTA3

metastasis‐associated gene 3

NuRD

nucleosome remodelling and deacetylase

TAC

transverse aortic constriction

TAK1

TGFβ‐activated kinase 1

TSA

trichostatin A

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Nuciferine relaxes rat mesenteric arteries through endothelium‐dependent and ‐independent mechanisms

Background and Purpose

Nuciferine, a constituent of lotus leaf, is an aromatic ring‐containing alkaloid, with antioxidative properties. We hypothesize nuciferine might affect vascular reactivity. This study aimed at determining the effects of nuciferine on vasomotor tone and the underlying mechanism

Experimental Approach

Nuciferine‐induced relaxations in rings of rat main mesenteric arteries were measured by wire myographs. Endothelial NOS (eNOS) was determined by immunoblotting. Intracellular NO production in HUVECs and Ca²⁺ level in both HUVECs and vascular smooth muscle cells (VSMCs) from rat mesenteric arteries were assessed by fluorescence imaging.

Key Results

Nuciferine induced relaxations in arterial segments pre‐contracted by KCl or phenylephrine. Nuciferine‐elicited arterial relaxations were reduced by removal of endothelium or by pretreatment with the eNOS inhibitor L‐NAME or the NO‐sensitive guanylyl cyclase inhibitor ODQ. In HUVECs, the phosphorylation of eNOS at Ser¹¹⁷⁷ and increase in cytosolic NO level induced by nuciferine were mediated by extracellular Ca²⁺ influx. Under endothelium‐free conditions, nuciferine attenuated CaCl₂‐induced contraction in Ca²⁺‐free depolarizing medium. In the absence of extracellular calcium, nuciferine relieved the vasoconstriction induced by phenylephrine and the addition of CaCl₂. Nuciferine also suppressed Ca²⁺ influx in Ca²⁺‐free K⁺‐containing solution in VSMCs.

Conclusions and Implications

Nuciferine has a vasorelaxant effect via both endothelium‐dependent and ‐independent mechanisms. These results suggest that nuciferine may have a therapeutic effect on vascular diseases associated with aberrant vasoconstriction.

Linked Articles

This article is part of a themed section on Chinese Innovation in Cardiovascular Drug Discovery. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2015.172.issue-23

Abbreviations

[Ca²⁺]_i

intracellular calcium

[NO]_i

intracellular NO

DAF‐FM DA

4‐amino‐5‐methylamino‐2′,7′‐difluorofluorescein diacetate

EDHF

endothelium‐derived hyperpolarizing factor

eNOS

endothelial NOS

Fluo‐4 AM

fluo‐4‐acetoxymethylester

iNOS

inducible NOS

L‐NAME

Nω‐nitro‐L‐arginine methyl ester

ODQ

1H‐[1,2,4]oxadizolo[4,3‐a]quinoxalin‐1‐one

VDCCs

voltage‐dependent Ca²⁺ channels

VSMCs

vascular smooth muscle cells

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Cryptotanshinone,an orally bioactive herbal compound from Danshen,attenuates atherosclerosis in apolipoprotein E‐deficient mice: role of lectin‐like oxidized LDL receptor‐1 (LOX‐1)

Background and Purpose

Cryptotanshinone (CTS) is a major bioactive diterpenoid isolated from Danshen, an eminent medicinal herb that is used to treat cardiovascular disorders in Asian medicine. However, it is not known whether CTS can prevent experimental atherosclerosis. The present study was designed to investigate the protective effects of CTS on atherosclerosis and its molecular mechanisms of action.

Experimental Approach

Apolipoprotein E‐deficient (ApoE ^−/−) mice, fed an atherogenic diet, were dosed daily with CTS (15, 45 mg kg⁻¹ day⁻¹) by oral gavage. In vitro studies were carried out in oxidized LDL (oxLDL)‐stimulated HUVECs treated with or without CTS.

Key Results

CTS significantly attenuated atherosclerotic plaque formation and enhanced plaque stability in ApoE ^−/− mice by inhibiting the expression of lectin‐like oxLDL receptor‐1 (LOX‐1) and MMP‐9, as well as inhibiting reactive oxygen species (ROS) generation and NF‐κB activation. CTS treatment significantly decreased the levels of serum pro‐inflammatory mediators without altering the serum lipid profile. In vitro, CTS decreased oxLDL‐induced LOX‐1 mRNA and protein expression and, thereby, inhibited LOX‐1‐mediated adhesion of monocytes to HUVECs, by reducing the expression of adhesion molecules (intracellular adhesion molecule 1 and vascular cellular adhesion molecule 1). Furthermore, CTS inhibited NADPH oxidase subunit 4 (NOX4)‐mediated ROS generation and consequent activation of NF‐κB in HUVECs.

Conclusions and Implications

CTS was shown to have anti‐atherosclerotic activity, which was mediated through inhibition of the LOX‐1‐mediated signalling pathway. This suggests that CTS is a vasculoprotective drug that has potential therapeutic value for the clinical treatment of atherosclerotic cardiovascular diseases.

Linked Articles

This article is part of a themed section on Chinese Innovation in Cardiovascular Drug Discovery. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2015.172.issue-23

Abbreviations

ApoE^−/−

apolipoprotein E deficient

CD36

cluster of differentiation 36

CTS

cryptotanshinone

HCD

high cholesterol diet

ICAM‐1

intracellular adhesion molecule 1

LOX‐1

lectin‐like oxidized low‐density lipoprotein receptor‐1

NOX4

NADPH oxidase subunit 4

oxLDL

oxidized low‐density lipoprotein

ROS

reactive oxygen species

SMCs

smooth muscle cells

SR‐A

scavenger receptor‐A

VCAM‐1

vascular cellular adhesion molecule 1

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Activation of TRPV1 attenuates high salt‐induced cardiac hypertrophy through improvement of mitochondrial function

Background and Purpose

High‐salt diet induces cardiac remodelling and leads to heart failure, which is closely related to cardiac mitochondrial dysfunction. Transient receptor potential (TRP) channels are implicated in the pathogenesis of cardiac dysfunction. We investigated whether activation of TRP vanilloid (subtype 1) (TRPV1) channels by dietary capsaicin can, by ameliorating cardiac mitochondrial dysfunction, prevent high‐salt diet‐induced cardiac hypertrophy.

Experimental Approach

Male wild‐type (WT) and TRPV1 ^−/− mice were fed a normal or high‐salt diet with or without capsaicin for 6 months. Their cardiac parameters and endurance capacity were assessed. Mitochondrial respiration and oxygen consumption were measured using high‐resolution respirometry. The expression levels of TRPV1, sirtuin 3 and NDUFA9 were detected in cardiac cells and tissues.

Key Results

Chronic high‐salt diet caused cardiac hypertrophy and reduced physical activity in mice; both effects were ameliorated by capsaicin intake in WT but not in TRPV1 ^−/− mice. TRPV1 knockout or high‐salt diet significantly jeopardized the proficiency of mitochondrial Complex I oxidative phosphorylation (OXPHOS) and reduced Complex I enzyme activity. Chronic dietary capsaicin increased cardiac mitochondrial sirtuin 3 expression, the proficiency of Complex I OXPHOS, ATP production and Complex I enzyme activity in a TRPV1‐dependent manner.

Conclusions and Implications

TRPV1 activation by dietary capsaicin can antagonize high‐salt diet‐mediated cardiac lesions by ameliorating its deleterious effect on the proficiency of Complex I OXPHOS. TRPV1‐mediated amendment of mitochondrial dysfunction may represent a novel target for management of early cardiac dysfunction.

Linked Articles

This article is part of a themed section on Chinese Innovation in Cardiovascular Drug Discovery. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2015.172.issue-23

Abbreviations

AngII

angiotensin II

CI

complex I

CII

complex II

CS

citrate synthase

EF

ejection fraction

ETC

electronic transport chain

FS

shortening fraction

HS

high‐salt diet

iRTX

5′‐iodoresiniferatoxin

LVH

left ventricular hypertrophy

LVID

left ventricular internal diameter

LVPW

left ventricular posterior wall

ND

normal‐salt diet

OXPHOS

oxidative phosphorylation

RER

respiration exchange ratio

RES

resveratrol

ROS

reactive oxygen species

TRPCs

transient potential receptor channels

TRPV1

transient receptor potential vanilloid subfamily member 1

TRPV1^−/−

TRPV1 knockout

WT

wild‐type

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Emerging role of hydrogen sulfide in hypertension and related cardiovascular diseases

Hydrogen sulfide (H₂S) has traditionally been viewed as a highly toxic gas; however, recent studies have implicated H₂S as a third member of the gasotransmitter family, exhibiting properties similar to NO and carbon monoxide. Accumulating evidence has suggested that H₂S influences a wide range of physiological and pathological processes, among which blood vessel relaxation, cardioprotection and atherosclerosis have been particularly studied. In the cardiovascular system, H₂S production is predominantly catalyzed by cystathionine γ‐lyase (CSE). Decreased endogenous H₂S levels have been found in hypertensive patients and animals, and CSE ^−/− mice develop hypertension with age, suggesting that a deficiency in H₂S contributes importantly to BP regulation. H₂S supplementation attenuates hypertension in different hypertensive animal models. The mechanism by which H₂S was originally proposed to attenuate hypertension was by virtue of its action on vascular tone, which may be related to effects on different ion channels. Both H₂S and NO cause vasodilatation and there is cross‐talk between these two molecules to regulate BP. Suppression of oxidative stress may also contribute to antihypertensive effects of H₂S. This review also summarizes the state of research on H₂S and hypertension in China. A better understanding of the role of H₂S in hypertension and related cardiovascular diseases will allow novel strategies to be devised for their treatment.

Linked Articles

This article is part of a themed section on Chinese Innovation in Cardiovascular Drug Discovery. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2015.172.issue-23

Abbreviation

2K1C

two‐kidney‐one‐clip

Ang II

angiotensin II

AOA

aminooxyacetic acid

AT₁ receptor

angiotensin II type 1 receptor

CBS

cystathionine‐β‐synthase

CO

carbon monoxide

CSE

cystathionine‐γ‐lyase

DBP

diastolic BP

eNOS

endothelial NOS

H₂S

hydrogen sulfide

I/R

ischaemia/reperfusion

L‐NAME

N^G‐nitro‐l‐arginine methyl ester

MAP

mean arterial pressure

MPST

3‐mercaptopyruvate sulfurtransferase

MWT

medial wall thickness

PAAT

pulmonary arterial acceleration time

PAG

DL‐propargylglycine

PHT

pulmonary hypertension

RVET

right ventricular ejection time

RVH

right ventricular hypertrophy

SBP

systolic BP

SHR

spontaneously hypertensive rat

SMCs

smooth muscle cells

VEGFR‐1

soluble fms‐like tyrosine kinase 1

VD

vas deferens

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The role of hexokinase in cardioprotection – mechanism and potential for translation

Mitochondrial permeability transition pore (mPTP) opening plays a critical role in cardiac reperfusion injury and its prevention is cardioprotective. Tumour cell mitochondria usually have high levels of hexokinase isoform 2 (HK2) bound to their outer mitochondrial membranes (OMM) and HK2 binding to heart mitochondria has also been implicated in resistance to reperfusion injury. HK2 dissociates from heart mitochondria during ischaemia, and the extent of this correlates with the infarct size on reperfusion. Here we review the mechanisms and regulations of HK2 binding to mitochondria and how this inhibits mPTP opening and consequent reperfusion injury. Major determinants of HK2 dissociation are the elevated glucose‐6‐phosphate concentrations and decreased pH in ischaemia. These are modulated by the myriad of signalling pathways implicated in preconditioning protocols as a result of a decrease in pre‐ischaemic glycogen content. Loss of mitochondrial HK2 during ischaemia is associated with permeabilization of the OMM to cytochrome c, which leads to greater reactive oxygen species production and mPTP opening during reperfusion. Potential interactions between HK2 and OMM proteins associated with mitochondrial fission (e.g. Drp1) and apoptosis (B‐cell lymphoma 2 family members) in these processes are examined. Also considered is the role of HK2 binding in stabilizing contact sites between the OMM and the inner membrane. Breakage of these during ischaemia is proposed to facilitate cytochrome c loss during ischaemia while increasing mPTP opening and compromising cellular bioenergetics during reperfusion. We end by highlighting the many unanswered questions and discussing the potential of modulating mitochondrial HK2 binding as a pharmacological target.

Linked Articles

This article is part of a themed section on Conditioning the Heart – Pathways to Translation. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2015.172.issue‐8

Abbreviations

Akt

also known as PKB

AMPK

AMP‐activated PK

ANT

adenine nucleotide translocase

Bad

Bcl‐2‐associated death promoter

Bak

Bcl‐2 homologous antagonist/killer

Bax

Bcl‐2‐like protein 4

Bcl‐2

B‐cell lymphoma 2

Bcl‐xL

Bcl‐2‐extra large

CK

creatine kinase

CsA

cyclosporine A

CyP‐D

cyclophilin D

Drp1

dynamin‐related protein 1

G‐6‐P

glucose‐6‐phosphate

GSK3β

glycogen synthase kinase 3β

HK

hexokinase

I/R

ischaemia/reperfusion

IF1

ATP synthase inhibitor factor 1

IMM

inner mitochondrial membrane

IP

ischaemic preconditioning

mPTP

mitochondrial permeability transition pore

OMM

outer mitochondrial membrane

Opa‐1

optic athrophy 1

PCr

phosphocreatine

PPIase

peptidylprolyl isomerase

ROS

reactive oxygen species

SR

sarcoplasmic reticulum

T₀

time of ischaemic rigor start

TAT‐HK2

cell‐permeable peptide of HK2 binding domain

TP

temperature preconditioning

TSPO

translocator protein of the outer membrane

VDAC

voltage‐dependent anion channel

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