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Background: Large-scale human and mechanistic mouse studies indicate a strong relationship between the microbiome-dependent metabolite trimethylamine N-oxide (TMAO) and several cardiometabolic diseases. This study aims to investigate the role of TMAO in the pathogenesis of abdominal aortic aneurysm (AAA) and target its parent microbes as a potential pharmacological intervention. Methods: TMAO and choline metabolites were examined in plasma samples, with associated clinical data, from 2 independent patient cohorts (N=2129 total). Mice were fed a high-choline diet and underwent 2 murine AAA models, angiotensin II infusion in low-density lipoprotein receptor–deficient ( Ldlr −/− ) mice or topical porcine pancreatic elastase in C57BL/6J mice. Gut microbial production of TMAO was inhibited through broad-spectrum antibiotics, targeted inhibition of the gut microbial choline TMA lyase (CutC/D) with fluoromethylcholine, or the use of mice genetically deficient in flavin monooxygenase 3 ( Fmo3 −/− ). Finally, RNA sequencing of in vitro human vascular smooth muscle cells and in vivo mouse aortas was used to investigate how TMAO affects AAA. Results: Elevated TMAO was associated with increased AAA incidence and growth in both patient cohorts studied. Dietary choline supplementation augmented plasma TMAO and aortic diameter in both mouse models of AAA, which was suppressed with poorly absorbed oral broad-spectrum antibiotics. Treatment with fluoromethylcholine ablated TMAO production, attenuated choline-augmented aneurysm initiation, and halted progression of an established aneurysm model. In addition, Fmo3 −/− mice had reduced plasma TMAO and aortic diameters and were protected from AAA rupture compared with wild-type mice. RNA sequencing and functional analyses revealed choline supplementation in mice or TMAO treatment of human vascular smooth muscle cells–augmented gene pathways associated with the endoplasmic reticulum stress response, specifically the endoplasmic reticulum stress kinase PERK. Conclusions: These results define a role for gut microbiota–generated TMAO in AAA formation through upregulation of endoplasmic reticulum stress–related pathways in the aortic wall. In addition, inhibition of microbiome-derived TMAO may serve as a novel therapeutic approach for AAA treatment where none currently exist.

Cardiac fibrosis is regulated by the activation and phenotypic switching of quiescent cardiac fibroblasts to active myofibroblasts, which have extracellular matrix (ECM) remodeling and contractile functions which play a central role in cardiac remodeling in response to injury. Here, we show that expression and activity of the RNA binding protein HuR is increased in cardiac fibroblasts upon transformation to an active myofibroblast. Pharmacological inhibition of HuR significantly blunts the TGFβ-dependent increase in ECM remodeling genes, total collagen secretion, in vitro scratch closure, and collagen gel contraction in isolated primary cardiac fibroblasts, suggesting a suppression of TGFβ-induced myofibroblast activation upon HuR inhibition. We identified twenty-four mRNA transcripts that were enriched for HuR binding following TGFβ treatment via photoactivatable ribonucleoside-enhanced crosslinking and immunoprecipitation (PAR-CLIP). Eleven of these HuR-bound mRNAs also showed significant co-expression correlation with HuR, αSMA, and periostin in primary fibroblasts isolated from the ischemic-zone of infarcted mouse hearts. Of these, WNT1-inducible signaling pathway protein-1 (Wisp1; Ccn4), was the most significantly associated with HuR expression in fibroblasts. Accordingly, we found Wisp1 expression to be increased in cardiac fibroblasts isolated from the ischemic-zone of mouse hearts following ischemia/reperfusion, and confirmed Wisp1 expression to be HuR-dependent in isolated fibroblasts. Finally, addition of exogenous recombinant Wisp1 partially rescued myofibroblast-induced collagen gel contraction following HuR inhibition, demonstrating that HuR-dependent Wisp1 expression plays a functional role in HuR-dependent MF activity downstream of TGFβ. In conclusion, HuR activity is necessary for the functional activation of primary cardiac fibroblasts in response to TGFβ, in part through post-transcriptional regulation of Wisp1.

Obesity is a rapidly growing epidemic worldwide, especially in the United States, and is associated with cardiovascular disease (CVD), diabetes, cancer, and a multitude of other comorbidities. Adipose tissue has been shown to act as an endocrine organ in the body and to mediate cardiac physiology. We have previously shown that deletion of HuR specifically in adipocytes (Adipo-HuR KO) induces cardiac fibrosis in mice, independent of traditional adipose/obesity co-morbidities (dyslipidemia, hypertension, diabetes).​ Deletion of HuR in the adipocyte affects both brown adipose tissue (BAT) depots as well as subcutaneous white adipose tissue (scWAT) depots. We have shown that HuR deletion in BAT (using a UCP1-driven cre model) maintains normal cardiac function compared to Adipo-HuR KO mice. This points toward scWAT being the primary mediator of cardiac pathology from adipose tissue, which is consistent with our previously published bioinformatic analysis suggesting HuR-dependent adipose tissue-derived extracellular vesicles (Ad-EVs) as the mechanism by which this occurs.The goal of this work is to identify the mechanisms by which HuR expression in subcutaneous white adipose tissue (scWAT) mediates cardiac function via Ad-EVs. Here, we show that Ad-EVs isolated from scWAT depots of our Adipo-HuR KO model induce significant hypertrophic signaling in vitro, compared to wild-type littermates. We also show that expression of HuR in scWAT specifically is decreased with obesity and age, suggesting a potential mechanistic link between obesity, HuR expression in scWAT, and CVD.In conclusion, our results demonstrate that loss of HuR expression in scWAT is sufficient to induce cardiac hypertrophy and fibrosis, in part through endocrine-mediated Ad-EV signaling. In addition, we are beginning to identify HuR-dependent gene expression patterns in human scWAT which may potentially play a significant role in this signaling axis. This work was supported by NIH grants R01-HL132111 and HL158671 (MT). RD is supported by a Peter Lauf Travel Award from the Ohio Physiological Society. SP is supported by an NIH Training grant T32HL125204 (PIs: Molkentin and Kranias). ARG was supported by American Heart Association Predoctoral Fellowship (916812). This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Myocardial ischemia/reperfusion (I/R) injury and the resulting cardiac remodeling is a common cause of heart failure. The RNA binding protein Human Antigen R (HuR) has been previously shown to reduce cardiac remodeling following both I/R and cardiac pressure overload, but the full extent of the HuR-dependent mechanisms within cells of the myocardium have yet to be elucidated. In this study, we applied a novel small molecule inhibitor of HuR to define the functional role of HuR in the acute response to I/R injury and gain a better understanding of the HuR-dependent mechanisms during post-ischemic myocardial remodeling. Our results show an early (two hours post-I/R) increase in HuR activity that is necessary for early inflammatory gene expression by cardiomyocytes in response to I/R. Surprisingly, despite the reductions in early inflammatory gene expression at two hours post-I/R, HuR inhibition has no effect on initial infarct size at 24-hours post-I/R. However, in agreement with previously published work, we do see a reduction in pathological remodeling and preserved cardiac function at two weeks post-I/R upon HuR inhibition. RNA-sequencing analysis of neonatal rat ventricular myocytes (NRVMs) at two hours post-LPS treatment to model damage associated molecular pattern (DAMP)-mediated activation of toll like receptors (TLRs) demonstrates a broad HuR-dependent regulation of pro-inflammatory chemokine and cytokine gene expression in cardiomyocytes. We show that conditioned media from NRVMs pre-treated with HuR inhibitor loses the ability to induce inflammatory gene expression in bone marrow derived macrophages (BMDMs) compared to NRVMs treated with LPS alone. Functionally, HuR inhibition in NRVMs also reduces their ability to induce endocrine migration of peripheral blood monocytesin vitroand reduces post-ischemic macrophage infiltration to the heartin vivo.In summary, these results suggest a HuR-dependent expression of pro-inflammatory gene expression by cardiomyocytes that leads to subsequent monocyte recruitment and macrophage activation in the post-ischemic myocardium.

Adipose tissue homeostasis plays a central role in cardiovascular physiology, and the presence of thermogenically active brown adipose tissue (BAT) has recently been associated with cardiometabolic health. We have previously shown that adipose tissue-specific deletion of HuR (Adipo-HuR-/-) reduces BAT-mediated adaptive thermogenesis, and the goal of this work was to identify the cardiovascular impacts of Adipo-HuR-/-. We found that Adipo-HuR-/- mice exhibit a hypercontractile phenotype that is accompanied by increased left ventricle wall thickness and hypertrophic gene expression. Furthermore, hearts from Adipo-HuR-/- mice display increased fibrosis via picrosirius red staining and periostin expression. To identify underlying mechanisms, we applied both RNA-seq and weighted gene coexpression network analysis (WGCNA) across both cardiac and adipose tissue to define HuR-dependent changes in gene expression as well as significant relationships between adipose tissue gene expression and cardiac fibrosis. RNA-seq results demonstrated a significant increase in proinflammatory gene expression in both cardiac and subcutaneous white adipose tissue (scWAT) from Adipo-HuR-/- mice that is accompanied by an increase in serum levels of both TNF-α and IL-6. In addition to inflammation-related genes, WGCNA identified a significant enrichment in extracellular vesicle-mediated transport and exosome-associated genes in scWAT, whose expression most significantly associated with the degree of cardiac fibrosis observed in Adipo-HuR-/- mice, implicating these processes as a likely adipose-to-cardiac paracrine mechanism. These results are significant in that they demonstrate the spontaneous onset of cardiovascular pathology in an adipose tissue-specific gene deletion model and contribute to our understanding of how disruptions in adipose tissue homeostasis may mediate cardiovascular disease.NEW & NOTEWORTHY The presence of functional brown adipose tissue in humans is known to be associated with cardiovascular health. Here, we show that adipocyte-specific deletion of the RNA binding protein HuR, which we have previously shown to reduce BAT-mediated thermogenesis, is sufficient to mediate a spontaneous development of cardiac hypertrophy and fibrosis. These results may have implications on the mechanisms by which BAT function and adipose tissue homeostasis directly mediate cardiovascular disease.

Canonical nonshivering thermogenesis (NST) in brown and beige fat relies on uncoupling protein 1–mediated heat generation, although alternative mechanisms of NST have been identified, including sarcoplasmic reticulum (SR)–calcium cycling. Intracellular calcium is a crucial cell signaling molecule for which compartmentalization is tightly regulated, and the sarco/endoplasmic reticulum calcium ATPase (SERCA) actively pumps calcium from the cytosol into the SR. In this review, we discuss the capacity of SERCA-mediated calcium cycling as a significant mediator of thermogenesis in both brown and beige adipocytes. Here, we suggest two primary mechanisms of SR calcium–mediated thermogenesis. The first mechanism is through direct uncoupling of the ATPase and calcium pump activity of SERCA, resulting in the energy of ATP catalysis being expended as heat in the absence of calcium transport. Regulins, a class of SR membrane proteins, act to decrease the calcium affinity of SERCA and uncouple the calcium transport function from ATPase activity, but remain largely unexplored in adipose tissue thermogenesis. A second mechanism is through futile cycling of SR calcium, whereby SERCA-mediated SR calcium influx is equally offset by SR calcium efflux, resulting in ATP consumption without a net change in calcium compartmentalization. A fuller understanding of the functional and mechanistic role of calcium cycling as a mediator of adipose tissue thermogenesis and how manipulation of these pathways can be harnessed for therapeutic gain remains unexplored. SIGNIFICANCE STATEMENT: Enhancing thermogenic metabolism in brown or beige adipose tissue may be of broad therapeutic utility to reduce obesity and metabolic syndrome. Canonical brown adipose tissue–mediated thermogenesis occurs via uncoupling protein 1 (UCP1). However, UCP1-independent pathways of thermogenesis, such as sarcoplasmic (SR) calcium cycling, have also been identified, but the regulatory mechanisms and functional significance of these pathways remain largely unexplored. Thus, this minireview discusses the state of the field regarding calcium cycling as a thermogenic mediator in adipose tissue.

The goal of this study was to define the functional role of adipocyte-specific expression of the RNA binding protein Human antigen R (HuR). Mice with an adipocyte-specific deletion of HuR (Adipo-HuR−/-) were generated by crossing HuR floxed (HuRfl/fl) mice with mice expressing adiponectin-driven cre-recombinase (Adipoq-cre). Our results show that Adipo-HuR−/- mice display a lean phenotype compared to wild-type littermate controls. HuR deletion results in a diet-independent reduction in percent body fat composition along with an increase in energy expenditure. Functionally, Adipo-HuR−/- mice show a significant impairment in acute adaptive thermogenesis (six hours at 4°C), but uncoupling protein 1 (UCP1) protein expression in brown adipose tissue (BAT) is unchanged compared to control. Pharmacological inhibition of HuR also results in a marked decline in core body temperature following acute cold challenge independent of UCP1 protein expression. Among the 588 HuR-dependent genes in BAT identified by RNA-seq analysis, gene ontology analysis shows a significant enrichment in mediators of calcium transport and signalling, almost all of which are decreased in Adipo-HuR−/- mice compared to control. In conclusion, adipocyte expression of HuR plays a central role in metabolic homoeostasis and mediates UCP1-independent thermogenesis in BAT, potentially through post-transcriptional control of intracellular calcium transport.Abbreviations: Adipo-HuR−/-: Adipocyte-specific HuR deletion mice; BAT: Brown adipose tissue; HuR: Human antigen R; UCP1: Uncoupling protein 1

Cardiac fibrosis is regulated by the activation and phenotypic switching of quiescent cardiac fibroblasts to active myofibroblasts, which have extracellular matrix (ECM) remodeling and contractile functions which play a central role in cardiac remodeling in response to injury. Here, we show that expression and activity of the RNA binding protein HuR is increased in cardiac fibroblasts upon transformation to an active myofibroblast. Pharmacological inhibition of HuR significantly blunts the TGFβ-dependent increase in ECM remodeling genes, total collagen secretion, in vitro scratch closure, and collagen gel contraction in isolated primary cardiac fibroblasts, suggesting a suppression of TGFβ-induced myofibroblast activation upon HuR inhibition. To delineate HuR-dependent mechanisms, we used photoactivatable ribonucleoside-enhanced crosslinking and immunoprecipitation (PAR-CLIP) to identify eleven mRNA transcripts that showed enriched HuR binding following TGFβ treatment as well as significant co-expression correlation with HuR, αSMA, and periostin using single-cell RNA-sequencing from ischemic-zone isolated fibroblasts. Of these, Wnt1-inducible signaling pathway protein-1 (Wisp1; Ccn4), was the most significantly associated with HuR expression in fibroblasts. Accordingly, we found Wisp1 expression to be increased in cardiac fibroblasts isolated from the ischemic-zone of mouse hearts following ischemia/reperfusion, and confirmed Wisp1 expression to be HuR-dependent in isolated fibroblasts. Finally, addition of exogenous recombinant Wisp1 is able to partially rescue myofibroblast contractile function following HuR inhibition, demonstrating that HuR-dependent Wisp1 expression plays a functional role in HuR-dependent MF activity downstream of TGFβ. In conclusion, HuR activity is necessary for the functional activation of primary cardiac fibroblasts in response to TGFβ, in part through post-transcriptional regulation of Wisp1.HIGHLIGHTSThe RNA binding protein HuR is highly expressed in cardiac fibroblasts and its expression strongly correlates with markers of active myofibroblastsHuR inhibition reduces migration, contraction, and ECM production activity of cardiac fibroblastsExpression of the secreted matricellular protein, Wisp1, is increased in a HuR-dependent manner following TGFβ treatmentRecombinant Wisp1 rescues myofibroblast contractile function following HuR inhibitionHuR-dependent expression of Wisp1 is necessary for myofibroblast activation

Arrhythmogenic cardiomyopathy (ACM) is characterized by life-threatening ventricular arrhythmias and sudden cardiac death and affects hundreds of thousands of patients worldwide. The deletion of Arginine 14 (p.R14del) in the phospholamban (PLN) gene has been implicated in the pathogenesis of ACM. PLN is a key regulator of sarcoplasmic reticulum (SR) Ca

Timely reperfusion is still the most effective approach to limit infarct size in humans. Yet, despite advances in care and reduction in door-to-balloon times, nearly 25% of patients develop heart failure postmyocardial infarction, with its attendant morbidity and mortality. We previously showed that cardioprotection results from a skin incision through the umbilicus in a murine model of myocardial infarction. In the present study, we show that an electrical stimulus or topical capsaicin applied to the skin in the same region induces significantly reduced infarct size in a murine model. We define this class of phenomena as nociceptor-induced conditioning (NIC) based on the peripheral nerve mechanism of initiation. We show that NIC is effective both as a preconditioning and postconditioning remote stimulus, reducing infarct size by 86% and 80%, respectively. NIC is induced via activation of skin C-fiber nerves. Interestingly, the skin region that activates NIC is limited to the anterior of the T9−T10 vertebral region of the abdomen. Cardioprotection after NIC requires the integrity of the spinal cord from the region of stimulation to the thoracic vertebral region of the origin of the cardiac nerves but does not require that the cord be intact in the cervical region. Thus, we show that NIC is a reflex and not a central nervous system-mediated effect. The mechanism involves bradykinin 2 receptor activity and activation of PKC, specifically, PKC-α. The similarity of the neuroanatomy and conservation of the effectors of cardioprotection supports that NIC may be translatable to humans as a nontraumatic and practical adjunct therapy against ischemic disease. NEW & NOTEWORTHY This study shows that an electrical stimulus to skin sensory nerves elicits a very powerful cardioprotection against myocardial infarction. This stimulus works by a neurogenic mechanism similar to that previously elucidated for remote cardioprotection of trauma. Nociceptor-induced conditioning is equally potent when applied before ischemia or at reperfusion and has great potential clinically.

The present study assessed whether tefillin use (tight, nonocclusive, wrapping of the arm) elicits a remote ischemic preconditioning (RIPC)-like effect in subjects with both acute and chronic use. RIPC, created by short bursts of ischemia-reperfusion, has not been successfully taken to the bedside. Several large population studies have found that Orthodox Jewish men (who wear tefillin almost daily) have decreased cardiovascular mortality compared with non-Orthodox counterparts. We hypothesized that tefillin use is a relevant component in triggering a preconditioning effect. Jewish men ( n = 20) were enrolled; 9 men were daily tefillin users (conditioned) and 11 men were nonusers of tefillin as controls (naïve). Subjects were evaluated for adherence to traditional Jewish practice, had vital signs measured, blood drawn for analysis of circulating cytokines and monocyte function, and underwent brachial flow-mediated dilation to evaluate vascular reactivity at baseline (basal) and after 30 min of using tefillin (acute treatment). Under basal conditions, both groups had similar peak systolic velocity (SV), diameter, and flow volume, although the conditioned group had higher SV at 120 s postdeflation ( P = 0.05). Acute tefillin use augmented artery diameter and flow volume in both groups, with conditioned subjects experiencing higher SV than control subjects at 90 and 120 s postdeflation ( P = 0.03 and P = 0.02, respectively). Conditioned subjects had decreased inflammation, monocyte migration and adhesion, and endothelial activation compared with control subjects at baseline. Acute use of tefillin did not significantly alter monocyte function in either group. In this pilot study, acute tefillin use improves vascular function, whereas chronic tefillin use is associated with an anti-inflammatory RIPC-like phenotype. NEW & NOTEWORTHY We hypothesized that tefillin use among Orthodox Jewish men (who practice a nonocclusive leather banding of their nondominant arm) will induce a remote ischemic preconditioning phenotype. Chronic use of tefillin in Orthodox Jewish men was associated with increased systolic velocity and attenuated inflammation and monocyte chemotaxis and adhesion versus Jewish men who do not wear tefillin. Acute use of tefillin in both populations augmented brachial artery diameter and blood flow but not inflammatory profiles compared with baseline.

Adipose tissue continues to gain appreciation for its broad role as an endocrine organ, and disruptions in adipose tissue homeostasis plays a central role in cardiovascular physiology. We have previously shown that expression of the RNA binding protein HuR in adipose tissue mediates energy expenditure, but the potential cardiovascular impacts of this finding have not been explored. We show here that adipose tissue-specific deletion of HuR (Adipo-HuR-/-) is sufficient to induce the spontaneous development of cardiac hypertrophy and fibrosis. Hearts from Adipo-HuR-/- mice have increased left ventricular (LV) ejection fraction, rate of pressure generation, and LV posterior wall thickness that is accompanied by an increase in LV/body weight ratio and hypertrophic gene expression. Furthermore, Adipo-HuR-/- hearts display increased fibrosis by picrosirius red staining and periostin expression. To identify underlying mechanisms, we applied both RNA-seq and weighted gene co-expression network analysis (WGCNA) to define HuR-dependent changes in gene expression as well as significant relationships between adipose tissue gene expression and LV mass. RNA-seq results demonstrate a significant increase in pro-inflammatory gene expression in the subcutaneous white adipose tissue (scWAT) from Adipo-HuR-/- mice that is accompanied by an increase in serum levels of both TNF-α and IL-6. WGCNA identified a significant enrichment in inflammation, apoptosis/cell death, and vesicle-mediated transport genes among those whose expression most significantly associated with CVD in Adipo-HuR-/-. In conclusion, we demonstrate that the loss of HuR expression in adipose tissue promotes the development of cardiac hypertrophy and fibrosis, potentially through modulation of inflammation and vesicle-mediated transport in scWAT.NEW AND NOTEWORTHYThis work demonstrates the spontaneous development of cardiac hypertrophy and fibrosis upon adipose tissue-specific deletion of the RNA binding protein HuR that appears to be mechanistically driven by HuR-dependent changes in inflammatory and extracellular vesicle transport mediating genes in the subcutaneous white adipose tissue. These results suggest that loss of HuR expression in adipose tissue in obesity, as demonstrated in mouse and humans by our group and others, may contribute to obesity-mediated CVD.

Myocardial infarction (MI), resulting from ischemia/reperfusion (I/R) injury due to the obstruction of coronary blood flow, affects an estimated 800,000 Americans annually resulting in a cost of nearly 12 billion dollars to the health care system. Recent medical advances have led to improved survival following acute MI, but unfortunately, the post-MI inflammatory and fibrotic remodeling of the heart is driving an increase in the prevalence of heart failure. Preliminary data from our lab shows that the RNA binding protein Human antigen R (HuR) undergoes nuclear-to-cytoplasmic translocation within 30 minutes and is increased in expression at both 2 hours and 7 days post-I/R. The objective of this work is to determine the mechanistic role of HuR on the regulation of cardiac cytokine/chemokine expression and the functional effect of HuR on macrophage infiltration and polarization post-I/R. Wild-type mice were subjected to 30 minutes of LAD (left anterior descending) coronary artery ligation (ischemia) followed by reperfusion with HuR inhibitor or vehicle control administered at the start of reperfusion. Our results show that inhibition of HuR reduces cardiac mRNA expression of IL-6, TNF-alpha, and ICAM-1 at 2 hours post-reperfusion, but does not affect initial (24 hour) infarct size. In addition, HuR inhibition reduces macrophage infiltration at 7 days post-I/R, as well as cardiac fibrosis and ventricular dilation while preserving cardiac function at 14 days post-I/R. Furthermore, H9c2s treated with HuR inhibitor blunts the mRNA expression of CCL2 after acute stimulation of lipopolysaccharide. In conclusion, we show that HuR inhibition at the time of reperfusion is protective against post-MI inflammatory and fibrotic remodeling through a reduction in inflammatory gene expression and macrophage infiltration. Previous work by the lab has demonstrated a direct role for HuR in cardiac myocytes, but these results also suggest that HuR-mediated gene expression in macrophages may play a role in post-MI inflammatory and fibrotic remodeling.

Cardiac fibrosis is characterized by the excessive deposition of extracellular matrix (ECM) and is an important target because excess ECM leads to a stiffened myocardium and worsens the prognosis of heart failure. Human Antigen R (HuR) is an RNA binding protein known to stabilize mRNA through binding to AU rich regions in the 3’UTR, and we have previously shown HuR to play a central role in the development of cardiac hypertrophy. To interrogate the role of HuR in cardiac fibrosis, we used both a small molecule inhibitor of HuR as well as an inducible genetic deletion of HuR in the activated cardiac myofibroblasts (iMF-HuR -/- ). Results using an in vitro scratch assay showed that primary adult cardiac fibroblasts treated with a small molecule inhibitor of HuR display a delayed wound healing response concomitant with a reduced expression of ECM remodeling genes. In vivo , we used an 8-week TAC (transverse aortic constriction) model of pressure overload to induce pathological cardiac remodeling. We hypothesized that deleting HuR in the activated fibroblasts would dampen myofibroblast-mediated ECM remodeling leading to a less stiff myocardium with reduced fibrotic burden and improved cardiac function in iMF-HuR -/- mice following pressure overload (TAC). However, echocardiography results show that cardiac function declined more rapidly in iMF-HuR -/- following TAC. The iMF-HuR -/- mice also had significantly enlarged hearts compared to the controls indicated by the heart weight/tibia length ratio. This suggests a critical role for HuR and myofibroblast activity in the early response to pressure overload. Future studies will focus on determining how the fibroblasts and the ECM composition/stiffness affect myocyte function in the early cardiac remodeling phase post-TAC and how HuR is involved in this relationship.

Tranilast is clinically indicated for the treatment of allergic disorders and is also a nonselective blocker of the transient receptor potential vanilloid 2 (TRPV2) channel. Previous studies have found that it has protective effects in various animal models of cardiac disease. Our laboratory has found that genetic deletion of TRPV2 results in a blunted hypertrophic response to increased afterload; thus, this study tested the hypothesis that tranilast through cardiomyocyte TRPV2 blockade can inhibit the hypertrophic response to pressure overload in vivo through transverse aortic constriction and ex vivo through isolated myocyte studies. The in vivo studies demonstrated that tranilast blunted the fibrotic response to increased afterload and, to a lesser extent, the hypertrophic response. After 4 weeks, this blunting was associated with improved cardiac function, although at 8 weeks, the cardiac function deteriorated similarly to the control group. Finally, the in vitro studies demonstrated that tranilast was not inhibiting these responses at the cardiomyocyte level. In conclusion, we demonstrated that tranilast blunting of the fibrotic and hypertrophic response occurs independently of cardiac TRPV2 channels and may be cardioprotective in the short term but not after prolonged administration.

Prostaglandin E2 (PGE2) is a lipid mediator of inflammation and its inhibition has become a popular drug target due to its harmful physiological roles. Diarylheptanoids are one class of compounds that have shown successful inhibition of PGE2. This paper reports the synthesis and PGE2 inhibitory activity of a series of analogues of a naturally occurring diarylheptanoid. The most efficacious compounds were examined for dose-dependent PGE2 inhibition. Among several promising compounds, the lead candidate exhibited an IC50 value of 0.56 ng/µL or 1.7 µM with no detectable toxicity at the highest dose of 10 ng/µL.

Adipose tissue is classically recognized as the primary site of lipid storage, but in recent years has garnered appreciation for its broad role as an endocrine organ comprising multiple cell types whose collective secretome, termed as adipokines, is highly interdependent on metabolic homeostasis and inflammatory state. Anatomical location (e.g. visceral, subcutaneous, epicardial etc) and cellular composition of adipose tissue (e.g. white, beige, and brown adipocytes, macrophages etc.) also plays a critical role in determining its response to metabolic state, the resulting secretome, and its potential impact on remote tissues. Compared with other tissues, the heart has an extremely high and constant demand for energy generation, of which most is derived from oxidation of fatty acids. Availability of this fatty acid fuel source is dependent on adipose tissue, but evidence is mounting that adipose tissue plays a much broader role in cardiovascular physiology. In this review, we discuss the impact of the brown, subcutaneous, and visceral white, perivascular (PVAT), and epicardial adipose tissue (EAT) secretome on the development and progression of cardiovascular disease (CVD), with a particular focus on cardiac hypertrophy and fibrosis.

Background Hepatocellular carcinoma (HCC) is the third most common cause of cancer-related death in the world. Choline deficiency has been well studied in the context of liver disease; however, less is known about the effects of choline supplementation in HCC. Objective The objective of this study was to test whether choline supplementation could influence the progression of HCC in a high-fat-diet (HFD)-driven mouse model. Methods Four-day-old male C57BL/6J mice were treated with the chemical carcinogen, 7,12-dimethylbenz[a]anthracene, and were randomly assigned at weaning to a cohort fed an HFD (60% kcal fat) or an HFD with supplemental choline (60% kcal fat, 1.2% choline; HFD+C) for 30 wk. Blood was isolated at 15 and 30 wk to measure immune cells by flow cytometry, and glucose-tolerance tests were performed 2 wk prior to killing. Overall tumor burden was quantified, hepatic lipids were measured enzymatically, and phosphatidylcholine species were measured by targeted MS methods. Gene expression and mitochondrial DNA were quantified by quantitative PCR. Results HFD+C mice exhibited a 50-90% increase in both circulating choline and betaine concentrations in the fed state (P ≤ 0.05). Choline supplementation resulted in a 55% decrease in total tumor numbers, a 67% decrease in tumor surface area, and a 50% decrease in hepatic steatosis after 30 wk of diet (P ≤ 0.05). Choline supplementation increased the abundance of mitochondria and the relative expression of β-oxidation genes by 21% and ∼75-100%, respectively, in the liver. HFD+C attenuated circulating myeloid-derived suppressor cells at 15 wk of feeding (P ≤ 0.05). Conclusions Choline supplementation attenuated HFD-induced HCC and hepatic steatosis in male C57BL/6J mice. These results suggest a therapeutic benefit of choline supplementation in blunting HCC progression.

Myocardial fibrosis is associated with many cardiac diseases and often leads to a worsened prognosis. In a healthy heart, cardiac fibroblasts are responsible for maintaining the extracellular matrix (ECM). In response to stress or injury, however, the fibroblasts activate to myofibroblasts and begin proliferating, migrating, and depositing excess ECM. This leads to decreased compliance and contractility of the myocardium, furthering the progression to heart failure. Dampening the chronic activation of fibroblasts, therefore, is an attractive target for future cardiac therapeutics. Human Antigen R (HuR) is an RNA binding protein known to stabilize mRNA through binding to AU rich regions in the 3’UTR. Our lab has previously utilized a myocyte-specific knockout of HuR to show that HuR plays an important role in cardiac fibrosis through mediating TGFβ gene expression in the myocytes. Additionally, pharmacological inhibition of HuR markedly reduced interstitial cardiac fibrosis in an 11-week transverse aortic constriction (TAC) mouse model of heart failure, quantifying the fibrosis with Masson’s Trichrome Stains, western blots, and qPCR of profibrotic markers. The goal of this work is to identify the functional role of HuR in mediating pro-fibrotic gene expression and ECM remodeling activity in cardiac fibroblasts. Our results demonstrate that HuR inhibition blunts the activation and wound healing activity of primary adult cardiac fibroblasts. Specifically, utilizing an in vitro scratch/wound healing assay we show that HuR inhibition significantly prolongs wound closure time and blunts the expression of profibrotic genes (e.g. collagen1a1, periostin, TGFb, fibronectin). Ongoing studies will determine the effect of HuR inhibition in a two-week isoproterenol pump (30mg/kg/day) model. Quantification of fibrosis and upstream signaling of fibroblast activation, such as TGFβ-dependent phosphorylation of SMAD2/3, will be assessed to determine the role of HuR in the initiation of fibrotic signaling.

Despite medical advances, cardiac ischemia/reperfusion (I/R) injury remains a leading cause of morbidity and a huge economic burden in the United States. RNA binding proteins are becoming recognized as potential mediators of cardiac physiology and pathology, but the role of HuR, an RNA binding protein highly expressed in myocytes, in acute cardiac I/R injury is unknown. HuR has been shown in other tissues to be a critical post-transcriptional mediator of pro-inflammatory chemokine and cytokine gene expression, and we have shown HuR to be activated (nuclear-to-cytoplasmic translocation) in cardiomyocytes 2 hours post-ischemia/reperfusion injury. To address the functional role of HuR in I/R, cardiomyocyte-specific HuR deletion mice (iCM-HuR -/- ) were subjected to 30 minutes of LAD (left anterior descending) coronary artery ligation followed by 24 hours of reperfusion. In parallel, a separate group of wild-type mice were subjected to 30 minutes ischemia with a pharmacological inhibitor of HuR given just prior to reperfusion. Analysis of infarct size showed a smaller infarct with both HuR genetic deletion (~10% decrease in infarct size compared to control, N=3, Pin vitro model of simulated I/R using neonatal rat ventricular myocytes. HuR inhibition results in a significant blunting of IL-6 and TNF-alpha gene expression two hours post-reperfusion in vivo , suggesting that HuR activity is necessary for the early induction of inflammatory gene expression networks. In addition, it appears that HuR inhibition attenuates macrophage infiltration following ischemia/reperfusion injury. In conclusion, our results suggest that inhibition of HuR is protective against cardiac I/R injury through a reduction in inflammatory gene expression.

RNA binding proteins represent an emerging class of proteins with a role in cardiac dysfunction. We show that activation of the RNA binding protein human antigen R (HuR) is increased in the failing human heart. To determine the functional role of HuR in pathological cardiac hypertrophy, we created an inducible cardiomyocyte-specific HuR-deletion mouse and showed that HuR deletion reduces left ventricular hypertrophy, dilation, and fibrosis while preserving cardiac function in a transverse aortic constriction (TAC) model of pressure overload-induced hypertrophy. Assessment of HuR-dependent changes in global gene expression suggests that the mechanistic basis for this protection occurs through a reduction in fibrotic signaling, specifically through a reduction in TGF-β (Tgfb) expression. Finally, pharmacological inhibition of HuR at a clinically relevant time point following the initial development of pathological hypertrophy after TAC also yielded a significant reduction in pathological progression, as marked by a reduction in hypertrophy, dilation, and fibrosis and preserved function. In summary, this study demonstrates a functional role for HuR in the progression of pressure overload-induced cardiac hypertrophy and establishes HuR inhibition as a viable therapeutic approach for pathological cardiac hypertrophy and heart failure.

The RNA binding protein Human antigen R (HuR) interacts with specific AU-rich domains in target mRNAs and is highly expressed in many cell types, including cardiomyocytes. However, the role of HuR in cardiac physiology is largely unknown. Our results show that HuR undergoes cytoplasmic translocation, indicative of its activation, in hypertrophic cardiac myocytes. Specifically, HuR cytoplasmic translocation is significantly increased in NRVMs (neonatal rat ventricular myocytes) following treatment with phenylephrine or angiotensin II, agonists of two independent Gαq-coupled GPCRs known to induce hypertrophy. This Gq-mediated HuR activation is dependent on p38 MAP kinase, but not canonical Gq-PKC signaling. Furthermore, we show that HuR activation is necessary for Gq-mediated hypertrophic growth of NRVMs as siRNA-mediated knockdown of HuR inhibits hypertrophy as measured by cell size and expression of ANF (atrial natriuretic factor). Additionally, HuR overexpression is sufficient to induce hypertrophic cell growth. To decipher the downstream mechanisms by which HuR translocation promotes cardiomyocyte hypertrophy, we assessed the role of HuR in the transcriptional activity of NFAT (nuclear factor of activated T cells), the activation of which is a hallmark of cardiac hypertrophy. Using an NFAT-luciferase reporter assay, we show an acute inhibition of NFAT transcriptional activity following pharmacological inhibition of HuR. In conclusion, our results identify HuR as a novel mediator of cardiac hypertrophy downstream of the Gq-p38 MAPK pathway, and suggest modulation of NFAT activity as a potential mechanism.

Objective— PAR2 (protease-activated receptor 2)-dependent signaling results in augmented inflammation and has been implicated in the pathogenesis of several autoimmune conditions. The objective of this study was to determine the effect of PAR2 deficiency on the development of atherosclerosis. Approach and Results— PAR2 mRNA and protein expression is increased in human carotid artery and mouse aortic arch atheroma versus control carotid and aortic arch arteries, respectively. To determine the effect of PAR2 deficiency on atherosclerosis, male and female low-density lipoprotein receptor–deficient ( Ldlr −/− ) mice (8–12 weeks old) that were Par2 +/+ or Par2 −/− were fed a fat- and cholesterol-enriched diet for 12 or 24 weeks. PAR2 deficiency attenuated atherosclerosis in the aortic sinus and aortic root after 12 and 24 weeks. PAR2 deficiency did not alter total plasma cholesterol concentrations or lipoprotein distributions. Bone marrow transplantation showed that PAR2 on nonhematopoietic cells contributed to atherosclerosis. PAR2 deficiency significantly attenuated levels of the chemokines Ccl2 and Cxcl1 in the circulation and macrophage content in atherosclerotic lesions. Mechanistic studies using isolated primary vascular smooth muscle cells showed that PAR2 deficiency is associated with reduced Ccl2 and Cxcl1 mRNA expression and protein release into the supernatant resulting in less monocyte migration. Conclusions— Our results indicate that PAR2 deficiency is associated with attenuation of atherosclerosis and may reduce lesion progression by blunting Ccl2 - and Cxcl1 -induced monocyte infiltration.

Prostaglandin E

Objective: Protease-activated receptor 2 (PAR-2)-dependent signaling results in augmented inflammation and has been implicated in the pathogenesis of several autoimmune conditions. While PAR-2 protein is present in coronary atherosclerotic lesions, the relevance of this finding has not been investigated in experimental models. The objective of this study was to determine the effects of PAR-2 on the development of atherosclerosis. Methods and Results: Relative expression of PAR-2 is increased in human coronary artery (21 fold) and mouse aortic arch (16 fold) atheromas versus control coronary and aortic arch arteries, respectively (P = 0.001). To determine the effect of PAR-2 deficiency on atherosclerosis, male low density lipoprotein receptor deficient ( Ldlr -/- ) mice (8-12 weeks old) that were Par-2 +/+ or Par-2 -/- were fed a fat and cholesterol-enriched diet for 12 (n = 10 each group) or 24 weeks (n = 5 each group). PAR-2 deficiency attenuated atherosclerosis in the aortic sinus and aortic root with no effects on total plasma cholesterol concentrations or lipoprotein distributions after 12 (P = 0.000433) and 24 (P = 0.037) weeks. These reductions were attributable to both hematopoietic and non-hematopoietic-derived PAR-2 from analysis of bone marrow experiments (n = 15 for each of 4 chimeric groups; P < 0.05). Mechanistic studies using ex vivo macrophages show that activation of PAR-2 results in augmented foam cell formation and apoptosis with treatment of oxidized low-density lipoprotein in conjunction with decreased expression of the nuclear receptor LXR-alpha and several cholesterol transporters. In addition, PAR-2 activation of ex-vivo cultured vascular smooth muscle cells (VSMCs) augments their transition to a macrophage-like state (after cholesterol treatment) via upregulation of human antigen R (HuR) and resultant stabilization of the transcription factor Krüppel-like factor 4 (KLF4). Conclusion: Our results indicate PAR-2 deficiency significantly attenuates the initiation (12 weeks) and reduces the progression (24 weeks) of atherosclerosis potentially via regulation of both lipid efflux from macrophages and the phenotypic modulation of VSMCs.

The cardiac regenerative capacity of MRL/MpJ mouse remains a controversy. Although the MRL mouse has been reported to exhibit minimal scarring and subsequent cardiac regeneration after cryoinjury of the right ventricle, multiple studies have been unable to replicate this cardiac regenerative capacity after both cryogenic and coronary ligation cardiac injury. Therefore, we evaluated the cardiac regenerative wound-healing response and functional recovery of MRL mice compared to C57 mice, in response to a clinically relevant left ventricular (LV) coronary ligation. Male MRL/MpJ+/+ and C57BL/6 mice underwent left coronary artery ligation followed by reperfusion. Cardiac function was evaluated by echocardiography [LV ejection fraction (LVEF), LV end-diastolic volume (LVEDV), LV mass, wall thickness] at 24 hours post-ischemia and weekly for 13 weeks thereafter. Hearts were also analyzed histologically for individual cardiomyocyte hypertrophy and cardiac fibrosis. Our results show that contrary to prior reports of cardiac regenerations, MRL mice progress to heart failure more rapidly following I/R injury as marked by a significant decrease in LVEF, increase in LVEDV, LV mass, individual myocyte size, and fibrosis in the post-ischemic myocardium. Therefore, we conclude that MRL mice do not exhibit regeneration of the LV or enhanced functional improvement in response to coronary ligation. However, unlike prior studies, we matched initial infarct size in MRL and C57 mice, used high frequency echocardiography, and histological analysis to reach this conclusion. The prospect of cardiac regeneration after ischemia in MRL mice seems to have attenuated interest, given the multiple negative studies and the promise of stem cell cardiac regeneration. However, our novel observation that MRL may possess an impaired compensated hypertrophy response makes the MRL mouse strain an interesting model in the study of cardiac hypertrophy.

Resumen En este articulo se revisan los biomarcadores no troponinicos con posibles sensibilidad y selectividad, que aportan una perspectiva diagnostica en el sindrome coronario agudo, y su posible uso en los algoritmos de estratificacion del riesgo. Dichos biomarcadores pueden ser utiles como analisis complementarios o alternativos a los de troponina cardiaca ( I o T) en el diagnostico precoz del sindrome coronario agudo, asi como para monitorizar su progresion y evaluar el pronostico. La informacion presentada en este articulo se basa en un analisis critico de una seleccion de la literatura biomedica disponible a traves de los motores de busqueda Scopus y MEDLINE-PubMed de la National Library of Medicine de Estados Unidos. La mayor parte de los articulos citados en este trabajo de revision y perspectiva, excepto unas pocas publicaciones historicas de referencia, se publico entre enero de 2000 y diciembre de 2013.

Probenecid was initially developed with the goal of reducing the renal excretion of antibiotics, specifically penicillin. It is still used for its uricosuric properties in the treatment in gout, but its clinical relevance has sharply fallen and is rarely used today for either. Interestingly, throughout the last 60 years, there have been a host of apparently unrelated studies using probenecid in the clinical and basic research arena, including its potential use in the diagnosis and treatment of depression and its use to prevent fura-2 leakage in calcium transient studies. Recently, it has been shown that it is also an agonist of the Transient Receptor Potential Vanilloid 2 channel. Due to its unique action and new findings implicating TRPV channels in physiology and in disease, probenecid may have a new future as a research tool, and perhaps as a clinical agent in the neurology and cardiology fields. We review the history of probenecid in this paper and its potential future uses.

The transcription factor Nuclear Factor Kappa B (NF-κB) has been shown to be cardioprotective after permanent coronary occlusion (PO) and late ischemic preconditioning (IPC), and yet it is cell injurious after ischemia/reperfusion (I/R) in the heart. There is limited information regarding NF-κB-dependent cardioprotection, and the NF-κB-dependent genes that contribute to the cardioprotection after PO are completely unknown. The objective of the study was to identify NF-κB-dependent genes that contribute to cardioprotection after PO. Microarray analysis was used to delineate genes that potentially contribute to the NF-κB-dependent cardioprotection by determining the overlap between the set of PO regulated genes and genes regulated by NF-κB, using mice with genetic abrogation of NF-κB activation in the heart. This analysis identified 16 genes as candidates for NF-κB-dependent effects after PO. This set of genes overlaps with, but is significantly different from the set of genes we previously identified as regulated by NF-κB after IPC. The genes encoding heat shock protein 70.3 (hspa1a) and heat shock protein 70.1 (hspa1b) were the most significantly regulated genes after PO and were up-regulated by NF-κB. Results using knockout mice show that Hsp70.1 contributes to NF-κB-dependent cardioprotection after PO and likely underlies, at least in part, the NF-κB-dependent cardioprotective effect. Our previous results show that Hsp70.1 is injurious after I/R injury. This demonstrates that, like NF-κB itself, Hsp70.1 has antithetical effects on myocardial survival and suggests that this may underlie the similar antithetical effects of NF-κB after different ischemic stimuli. The significance of the research is that understanding the gene network regulated by NF-κB after ischemic insult may lead to identification of therapeutic targets more appropriate for clinical development.

It has been shown that the transcription factor NF-kappaB is necessary for late phase cardioprotection after ischemic preconditioning (IPC) in the heart, and yet is injurious after ischemia/reperfusion (I/R). However the downstream gene expression programs that underlie the contribution of NF-kappaB to cardioprotection after late IPC are incompletely understood. The objective of this study was to delineate the specific genes that are regulated by NF-kappaB immediately after a late IPC stimulus and validate the methodology for the identification of NF-kappaB-dependent genes that contribute to cardioprotection. A directed microarray analysis identified 238 genes as up or downregulated in an NF-kappaB-dependent manner 3.5h after late IPC. Among these are several genes previously implicated in late IPC. Gene ontological analysis showed that the most significant group of NF-kappaB-dependent genes are heat shock response genes, including the genes encoding Hsp70.1 and Hsp70.3. Though an Hsp70.1/70.3 double knockout failed to exhibit cardioprotection, late IPC was intact in the Hsp70.1 single knockout. After I/R, the Hsp70.1/70.3 double knockout and the Hsp70.1 single knockout had significantly increased and reduced infarct size, respectively. These results delineate the immediate NF-kappaB-dependent transcriptome after late IPC. One of the major categories of NF-kappaB-dependent genes induced by late IPC is the heat shock response. The results of infarct studies confirm that Hsp70.3 is protective after IPC. However, though Hsp70.1 and Hsp70.3 are coordinately regulated, their functions are opposing after I/R injury.

The RNA binding protein HuR (Human antigen R) interacts with specific AU-rich domains in target mRNAs and is highly expressed in many cell types, including cardiomyocytes. However, the role of HuR in cardiac physiology is largely unknown. Our results show that HuR undergoes cytoplasmic translocation, indicative of its activation, in hypertrophic mouse cardiac myocytes at 8 weeks post-transverse aortic constriction (TAC). To determine the role of HuR in the development of cardiac hypertrophy, we have created a novel mouse model of cardiac myocyte-specific deletion of HuR. While cardiac-specific HuR deletion mice do not show an overt basal phenotype, they have preserved ejection fraction and reduced ventricular remodeling (hypertrophy and chamber dilation) compared to wild-type littermates at 8 weeks following TAC. Furthermore, HuR activation in the hypertrophic heart is strongly co-localized with regions of fibrosis. To this end, we show that HuR knockdown reduced hypertrophy and pro-fibrotic TGF-β gene expression in a phenylephrine treated neonatal rat ventricular myocyte (NRVM) model of hypertrophy. Thus, our results suggest that HuR activation in cardiac myocytes promotes pathogical hypertrophy and initiation of cardiac fibrosis via myocyte expression of TGF-β. These findings are significant as we have identified HuR as a novel mediator of pathological hypertrophy and suggest a pro-fibrotic role as a potential mechanism for this effect.

Previous studies have demonstrated improvement of cardiac function occurs with acute consumption of a high-fat diet (HFD) after myocardial infarction (MI). However, no data exist addressing the effects of acute HFD upon the extent of injury after MI. This study investigates the hypothesis that short-term HFD, prior to infarction, protects the heart against ischemia-reperfusion (I/R) injury through NF-κB-dependent regulation of cell death pathways in the heart. Data show that an acute HFD initiates cardioprotection against MI (>50% reduction in infarct size normalized to risk region) after 24 h to 2 wk of HFD, but protection is completely absent after 6 wk of HFD, when mice are reported to develop pathophysiology related to the diet. Furthermore, cardioprotection after 24 h of HFD persists after an additional 24 h of normal chow feeding and was found to be dependent upon NF-κB activation in cardiomyocytes. This study also indicates that short-term HFD activates autophagic processes (beclin-1, LC-3) preischemia, as seen in other protective stimuli. Increases in beclin-1 and LC-3 were found to be NF-κB-dependent, and administration of chloroquine, an inhibitor of autophagy, abrogated cardioprotection. Our results support that acute high-fat feeding mediates cardioprotection against I/R injury associated with a NF-κB-dependent increase in autophagy and reduced apoptosis, as has been found for ischemic preconditioning.

Transient receptor potential vanilloid 2 (TRPV2) is a ligand-gated ion channel that is expressed in cadiomyocytes and increases contractility following stimulation with probenecid, an agonist for T...

Summary NaV1.9 regulates normal colonic afferent mechanosensation and is required for hypersensitivity to noxious inflammatory mediators and those derived from inflammatory bowel disease tissues., Chronic visceral pain affects millions of individuals worldwide and remains poorly understood, with current therapeutic options constrained by gastrointestinal adverse effects. Visceral pain is strongly associated with inflammation and distension of the gut. Here we report that the voltage-gated sodium channel subtype NaV1.9 is expressed in half of gut-projecting rodent dorsal root ganglia sensory neurons. We show that NaV1.9 is required for normal mechanosensation, for direct excitation and for sensitization of mouse colonic afferents by mediators from inflammatory bowel disease tissues, and by noxious inflammatory mediators individually. Excitatory responses to ATP or PGE2 were substantially reduced in NaV1.9−/− mice. Deletion of NaV1.9 substantially attenuates excitation and subsequent mechanical hypersensitivity after application of inflammatory soup (IS) (bradykinin, ATP, histamine, PGE2, and 5HT) to visceral nociceptors located in the serosa and mesentery. Responses to mechanical stimulation of mesenteric afferents were also reduced by loss of NaV1.9, and there was a rightward shift in stimulus–response function to ramp colonic distension. By contrast, responses to rapid, high-intensity phasic distension of the colon are initially unaffected; however, run-down of responses to repeat phasic distension were exacerbated in NaV1.9−/− afferents. Finally colonic afferent activation by supernatants derived from inflamed human tissue was greatly reduced in NaV1.9−/− mice. These results demonstrate that NaV1.9 is required for persistence of responses to intense mechanical stimulation, contributes to inflammatory mechanical hypersensitivity, and is essential for activation by noxious inflammatory mediators, including those from diseased human bowel. These observations indicate that NaV1.9 represents a high-value target for development of visceral analgesics.

Biomarkers, other than cardiac troponin, with potential sensitivity and selectivity that provide diagnostic and prognostic insights into the tissue-specific injury processes underlying acute coronary syndrome and their possible use in risk stratification algorithms are discussed. Such biomarkers may be useful as complementary or alternative to cardiac troponin (I or T) assays in early diagnosis of acute coronary syndrome, as well as for monitoring acute coronary syndrome progression and prognosis assessment. The information included in this article is based on a critical analysis of selected published biomedical literature accessible through the United States National Library of Medicine's MEDLINE-PubMed and Scopus search engines. The majority of articles cited in this review and perspective, except for a few historical publications as background, were published between January 2000 and December 2013.