Abstract 57: Therapeutic Effects of Small Molecule Gβγ Inhibition in Pressure Overload Heart Failure

2012 ◽  
Vol 111 (suppl_1) ◽  
Author(s):  
Fadia A Kamal ◽  
Alan V Smrcka ◽  
Burns C Blaxall
Keyword(s):  
Heart Failure ◽  
Small Molecule ◽  
Interstitial Fibrosis ◽  
Plasma Catecholamines ◽  
Pressure Overload ◽  
Plasma Catecholamine ◽  
Therapeutic Effects ◽  
Mrna Levels ◽  
Group V ◽  
Plasma Catecholamine Concentrations

Heart failure (HF) is a progressive disease with rapidly increasing rates of morbidity and mortality; it is the leading cause of death worldwide. Elevated sympathetic nervous system activity, a salient feature of HF progression, leads to pathologic attenuation and desensitization of β-adrenergic receptors (β-ARs) due in part to Gβγ-mediated signaling. We recently reported that novel small molecule Gβγ inhibitors selectively block specific Gβγ signals and halt HF progression in pharmacologic and transgenic mouse models of HF. We assessed the hypothesis that the Gβγ inhibitor Gallein could be salutary in treating pre-existing HF in a clinically relevant model. We utilized the pressure-overload HF model of mouse transverse aortic constriction (TAC). Four weeks post-TAC, mice received daily IP injections of vehicle (PBS; group V) or Gallein (10mg/Kg/day; group G) for eight weeks. Gallein treatment improved survival (7 of 9 mice survived vs. 5 of 9 mice in group V) and cardiac function (%EF 75.2 ± 7.5 vs 35.6 ± 17.2 in group V, +dP/dt (mmHg/sec) 7022 ± 485.3 vs. 3584 ± 598.6 in group V), -dP/dt (mmHg/sec) -5826 ± 910.7 vs. -3260 ± 62.3 in group V, LVEDP (mmHg) 11.5 ± 3.7 vs. 29.45 ± 3.6 in group V). In addition, gallein reduced cardiac hypertrophy (HW/BW (mg/g) 5.8 ± 0.3 vs. 8.8 ± 1.1 in group V) and plasma catecholamine concentrations (adrenaline (ng/ml) 1.3 ± 0.3 vs. 6.6 ± 2.8 in group V, noradrenaline (ng/ml) 3.6 ± 0.6 vs. 15.1 ± 3.6 in group V). Reduction of interstitial fibrosis as well as mRNA levels of α-SMA, TNF-α, and IL-6 was observed in the hearts of Gallein treated animals (59.7 ± 14.1%, 43.8 ± 9.3% and 28.5 ± 3.5% relative to group V, respectively). On the molecular level, Gallein treated mice showed less GRK2 and PI3Kγ membrane recruitment, and less Akt activation (42.9 ± 7.1%, 66.7 ± 13.3% and 46.2 ± 7.7% relative to group V, respectively) in myocardial lysates. In conclusion , these data suggest a possible therapeutic role for small molecule Gβγ inhibition in halting the progression of HF, potentially via inhibition of the Gβγ-GRK2-PI3Kγ-Akt pathway. The combined effect of halting HF progression and reducing plasma catecholamines suggests a possible systemic role for small molecule Gβγ inhibition in both the heart and the adrenal gland.

Abstract 319: Small Molecule Gβγ Inhibition Attenuates Cardiac Fibroblast Inflammatory and Pro-Fibrotic Signaling

2014 ◽  
Vol 115 (suppl_1) ◽  
Author(s):  
Joshua G Travers ◽  
Fadia A Kamal ◽  
Michael S Burhans ◽  
Burns C Blaxall
Keyword(s):  
Myocardial Fibrosis ◽  
Inflammatory Cytokines ◽  
Small Molecule ◽  
Therapeutic Potential ◽  
Interstitial Fibrosis ◽  
Pressure Overload ◽  
Cardiac Fibroblast ◽  
Ventricular Compliance ◽  
Pro Inflammatory Cytokines

Heart failure (HF) is a devastating disease characterized by chamber remodeling, interstitial fibrosis and reduced ventricular compliance. Prolonged sympathetic overstimulation promotes excess signaling through G-protein Gβγ subunits and ultimately results in pathologic GRK2-mediated β-adrenergic receptor (β-AR) downregulation. We have recently demonstrated the therapeutic potential of the small molecule Gβγ-GRK2 inhibitor Gallein in limiting HF progression. Pathologic activation of the cardiac fibroblast (CF) induces the transition to a myofibroblast phenotype, which plays a fundamental role in myocardial fibrosis and remodeling. We hypothesized that Gβγ-GRK2 inhibition plays an important functional role in the CF to attenuate pathologic CF activation, inflammation and interstitial fibrosis. To explore the effect of Gβγ-GRK2 inhibition on inflammation and pro-fibrotic signaling, mice were subjected to 7 days of transverse aortic constriction, a pressure-overload model of HF. In addition to the attenuation in overall cardiac hypertrophy, animals treated with Gallein displayed reduced expression of pro-inflammatory cytokines, including macrophage inflammatory protein 1 alpha (MIP-1α) and MIP-1β, along with Interleukin-6, as assessed by qPCR. Gallein-treated animals also exhibited diminished pro-fibrotic signaling, as evidenced by a reduction in the expression of TGFβ, a major driver of myocardial fibrosis, and decreased expression of collagen. To recapitulate these findings in vitro, primary adult mouse ventricular fibroblasts were pathologically stimulated using Isoproterenol (ISO, β-AR agonist) or Angiotensin II and treated +/- Gallein for 24 hours. CFs treated with Gallein displayed an analogous reduction in the expression of these pro-inflammatory cytokines and collagen. In summary, these data suggest a potential therapeutic role for small molecule Gβγ-GRK2 inhibition in limiting pathologic myofibroblast activation, inflammation and interstitial fibrosis. We believe this fibroblast-targeted approach will lead to the refinement of existing targets and compounds, and possibly the generation of novel therapeutics for the treatment of HF.

Abstract 744: Arrhythmogenesis in Heart Failure: Role of Interstitial Fibrosis

Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Jorge E Massare ◽  
R. Haris Naseem ◽  
Jeff M Berry ◽  
Farhana Rob ◽  
Joseph A Hill
Keyword(s):  
Heart Failure ◽  
Interstitial Fibrosis ◽  
Systolic Dysfunction ◽  
Ventricular Tachyarrhythmia ◽  
Severe Heart Failure ◽  
Pressure Overload ◽  
Cellular Events ◽  
Action Potential Prolongation

Background: Sudden cardiac death due to ventricular tachyarrhythmia (VT) accounts for a large number of deaths in patients with heart failure. Several cellular events which occur during pathological remodeling of the failing ventricle are implicated in the genesis of VT, including action potential prolongation, dysregulation of intercellular coupling, and fibrosis. Interestingly, transgenic mice over-expressing constitutively active PKD (caPKD) develop severe heart failure without interstitial fibrosis, an otherwise prominent feature of the disease. The goal here was to define the role of interstitial fibrosis in the proarrhythmic phenotype of failing myocardium. Methods and Results: We performed echocardiographic, electrocardiographic, and in vivo electrophysiologic studies in 8 –10 week old caPKD mice (n=12). Similar studies were performed in mice with load-induced heart failure induced by surgical pressure overload (sTAB, n=10), a model of heart failure with prominent interstitial fibrosis. caPKD and sTAB mice showed similar degrees of ventricular dilation (LV systolic dimension caPKD 2.4±0.8 mm vs 3.0±0.9 sTAB, p=0.18) and severe systolic dysfunction (% fractional shortening caPKD 25±11 vs 28±11 sTAB, p=0.62). Yet, caPKD mice showed minimal interstitial fibrosis, comparable to unoperated controls. With the exception of ventricular refractory period, which was higher in caPKD (48±11 msec vs 36±7 TAB and 40±8 WT, p<0.05), other electrocardiographic and electrophysiologic variables were similar among the 3 groups (p=NS), including heart rate, QT duration, and mean VT threshold. As expected, VT (≥3beats) was readily inducible by programmed stimulation in sTAB mice (7/10). By contrast, VT was less inducible in caPKD mice (4/12; p=0.1 vs TAB and <0.05 vs WT), and uninducible in unoperated controls (0/12). VT was polymorphic in both models, but episodes of VT were both slower (VT cycle length caPKD 58±4.0 msec vs 48±1 sTAB, p=0.016) and longer in caPKD mice (caPKD 1.8±0.7 sec vs 0.47±0.3 sTAB, p=0.038). Conclusion: Interstitial fibrosis contributes to the inducibility, maintenance, and rate of VT in heart failure. These findings highlight the importance of anti-remodeling therapies known to target fibrosis in heart disease.

Sample preparation with ion-exchange resin before liquid-chromatographic determination of plasma catecholamines.

1983 ◽  
Vol 29 (7) ◽  
pp. 1426-1428 ◽  
Author(s):  
K N Frayn ◽  
P F Maycock
Keyword(s):  
Cation Exchange ◽  
High Performance ◽  
Exchange Resin ◽  
Plasma Catecholamines ◽  
Cation Exchange Resin ◽  
Chromatographic Determination ◽  
Ion Exchange Resin ◽  
Plasma Catecholamine ◽  
Plasma Catecholamine Concentrations ◽  
Liquid Chromatographic

Abstract Estimation of plasma catecholamine concentrations by "high-performance" liquid chromatography, although increasingly used, still presents difficulties. We describe a method for clean-up of plasma samples on cation-exchange resin before they are extracted with alumina. This procedure eliminates many of the interfering compounds often present in plasma extracts prepared with the alumina treatment alone. The method can be adapted to use commercially available disposable cation-exchange columns.

Pentobarbital effects on plasma catecholamines: temperature, heart rate, and blood pressure

1985 ◽  
Vol 248 (1) ◽  
pp. E95-E100 ◽  
Author(s):  
D. Baum ◽  
J. B. Halter ◽  
G. J. Taborsky ◽  
D. Porte
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Nervous System ◽  
Animal Models ◽  
Sympathetic Nervous System ◽  
Rectal Temperature ◽  
Plasma Catecholamines ◽  
Plasma Catecholamine ◽  
Sympathetic Nervous ◽  
Plasma Catecholamine Concentrations

The effects of intravenous pentobarbital were studied in dogs. Plasma pentobarbital concentrations were inversely related to epinephrine and norepinephrine concentrations. Plasma catecholamines appeared fully suppressed at pentobarbital levels greater than 25-30 micrograms/ml. Furthermore, pentobarbital levels were negatively related to rectal temperature, heart rate, and mean blood pressure. The methods of pentobarbital administration influenced plasma pentobarbital as well as epinephrine and norepinephrine levels, temperature, heart rate, and blood pressure. These observations suggest the possibility that pentobarbital inhibits the sympathetic nervous system, which in turn may affect temperature, heart rate, and blood pressure. Because pentobarbital anesthesia affects plasma catecholamine concentrations, the regimen used in animal models requires consideration when interpreting data potentially influenced by the sympathetic nervous system.

scholarly journals Osteopontin RNA aptamer can prevent and reverse pressure overload-induced heart failure

2017 ◽  
Vol 113 (6) ◽  
pp. 633-643 ◽  
Author(s):  
Jihe Li ◽  
Keyvan Yousefi ◽  
Wen Ding ◽  
Jayanti Singh ◽  
Lina A. Shehadeh
Keyword(s):  
Heart Failure ◽  
Cardiac Function ◽  
Cardiac Dysfunction ◽  
Cardiac Fibrosis ◽  
Cardiac Myocyte ◽  
Pressure Overload ◽  
Cardiomyocyte Hypertrophy ◽  
Therapeutic Effects ◽  
Rna Aptamer ◽  
Myocyte Hypertrophy

Aims Cardiac myocyte hypertrophy, the main compensatory response to chronic stress in the heart often progresses to a state of decompensation that can lead to heart failure. Osteopontin (OPN) is an effector for extracellular signalling that induces myocyte growth and fibrosis. Although increased OPN activity has been observed in stressed myocytes and fibroblasts, the detailed and long term effects of blocking OPN signalling on the heart remain poorly defined. Targeting cardiac OPN protein by an RNA aptamer may be beneficial for tuning down OPN pathologic signalling. We aimed to demonstrate the therapeutic effects of an OPN RNA aptamer on cardiac dysfunction. Methods and results In vivo, we show that in a mouse model of pressure overload, treating at the time of surgeries with an OPN aptamer prevented cardiomyocyte hypertrophy and cardiac fibrosis, blocked OPN downstream signalling (PI3K and Akt phosphorylation), reduced expression of extracellular matrix (Lum, Col3a1, Fn1) and hypertrophy (Nppa, Nppb) genes, and prevented cardiac dysfunction. Treating at two months post-surgeries with the OPN aptamer reversed cardiac dysfunction and fibrosis and myocyte hypertrophy. While genetic homozygous deletion of OPN reduced myocardial wall thickness, surprisingly cardiac function and myocardial fibrosis, specifically collagen deposition and myofibroblast infiltration, were worse compared with wild type mice at three months of pressure overload. Conclusion Taken together, these data demonstrate that tuning down cardiac OPN signalling by an OPN RNA aptamer is a novel and effective approach for preventing cardiac hypertrophy and fibrosis, improving cardiac function, and reversing pressure overload-induced heart failure.

scholarly journals The Effects of Guizhi Gancao Decoction on Pressure Overload-Induced Heart Failure and Posttranslational Modifications of Tubulin in Mice

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Hui-hua Chen ◽  
Pei Zhao ◽  
Jing Tian ◽  
Wei Guo ◽  
Ming Xu ◽  
...  
Keyword(s):  
Heart Failure ◽  
Cardiovascular Diseases ◽  
Posttranslational Modifications ◽  
Volume Fraction ◽  
Pressure Overload ◽  
Therapeutic Effects ◽  
Protective Effects ◽  
Immunofluorescent Analysis ◽  
Traditional Chinese Medical ◽  
Hemodynamic Measurements

Guizhi Gancao Decoction (GGD), a traditional Chinese medical recipe, has been widely used in the treatment of cardiovascular diseases in China for centuries. The present study was carried out to determine whether GGD exerts direct protective effects against pressure overload-induced heart failure. Moreover, we investigated whether GGD affects tubulin expression and posttranslational modifications. We demonstrated that GGD ameliorated TAC caused cardiac hypertrophy by gravimetric and echocardiography analysis in C57BL/6 mice. We found that GGD abrogated TAC-induced myocardium fibrosis by Masson’s staining and collagen volume fraction (CVF) analysis. By using pressure-volume hemodynamic measurements, we found that GGD prevented TAC-induced cardiac systolic and diastolic dysfunction. Immunoblotting and immunofluorescent analysis revealed that GGD abrogated TAC-induced detyrosination and acetylation abnormalities on microtubules. Our present study demonstrated potential therapeutic effects of GGD against pressure overload-induced heart failure.

Abstract 299: Simultaneous Cardiac And Adrenal Small Molecule GPCR-Gβ? Inhibition Halts The Progression Of Pressure Overload Heart Failure

2013 ◽  
Vol 113 (suppl_1) ◽  
Author(s):  
Fadia A Kamal ◽  
Deanne Mickelsen ◽  
Jacob Moalem ◽  
Stephen R Hammes ◽  
Alan V Smrcka ◽  
...  
Keyword(s):  
Heart Failure ◽  
Adrenal Gland ◽  
Small Molecule ◽  
Adrenal Glands ◽  
Pressure Overload ◽  
Salient Feature ◽  
Therapeutic Benefit ◽  
Pharmacologic Therapy ◽  
Inhibitory Function ◽  
Gsk 3Β

Heart failure (HF) is a progressive disease with rapidly increasing rates of morbidity and mortality. Elevated sympathetic nervous system activity, a salient feature of HF progression, leads to pathologic attenuation and desensitization of β-adrenergic receptors (β-ARs) due in part to Gβγ-mediated signaling. In the current study, we assessed the hypothesis that the small molecule Gβγ inhibitor “gallein” is salutary in treating pre-existing HF in a clinically relevant model (pressure-overload HF model of mouse transverse aortic constriction (TAC)) by simultaneously normalizing adrenergic receptor signaling in the heart and the adrenal gland. Four weeks post-TAC, mice received daily i.p. injections of vehicle or gallein for eight weeks (n=6-8 per group). Serial echocardiography was performed through out the study. At the end of the experiment, hemodynamic studies were performed, mice were sacrificed, blood, heart, and adrenal glands were harvested for further analysis. Gallein treatment improved survival and cardiac function and reduced cardiac hypertrophy, remodeling, and fetal genes expression in TAC mice. On the molecular level, gallein recovered membrane β-AR density and attenuated GRK2-PI3Kγ membrane recruitment, and Akt-GSK-3β signaling in TAC hearts. A salutary adrenal effect of gallein was obtained in cultured mice adrenal glands and human pheochromocytoma tissue (n=3), where direct gallein treatment restored α2-AR feedback inhibitory function and concurrently reduced catecholamine production. Moreover, gallein treatment attenuated adrenal hypertrophy in TAC mice and downregulated tyrosine hydroxylase and chromogranin A protein expression in adrenal glands from TAC mice and cultured pheochromocytoma tissue as well. In summary, our data suggest gallein as a systemic pharmacologic therapy with substantial therapeutic benefit in HF by simultaneously normalizing pathologic Gβγ-GRK2 signaling and recovering AR signaling in both the heart and the adrenal gland. In the heart, gallein mediated attenuation of cardiac remodeling probably involves inhibiting GRK2-PI3K-Akt signaling. Our data also suggest a role for small molecule Gβγ inhibition in other diseases of elevated catecholamine release, such as pheochromocytoma.

Abstract 74: The Role of Fibroblast-specific Canonical Tgfβ Signaling in Cardiac Fibrosis

2015 ◽  
Vol 117 (suppl_1) ◽  
Author(s):  
Hadi Khalil ◽  
Onur Kanisicak ◽  
Robert N. Correll ◽  
Michelle Sargent ◽  
Jeffery D. Molkentin
Keyword(s):  
Heart Failure ◽  
Cardiac Fibrosis ◽  
Transforming Growth Factor ◽  
Interstitial Fibrosis ◽  
Contractile Activity ◽  
Cardiac Fibroblasts ◽  
Pressure Overload ◽  
Type I ◽  
Tgfβ Signaling ◽  
Chronic Heart Disease

Heart failure is a progressive disease characterized by cardiomyocyte loss, interstitial fibrosis, and chamber remodeling. During physiological conditions cardiac fibroblasts contribute to the homeostatic maintenance of myocardial structure as well as the maintenance of biochemical, mechanical and electrical properties of the heart. Injury and/or cytokine stimulation activate fibroblasts which transdifferentiate into myofibroblasts. These newly formed cells secrete extracellular matrix (ECM) for wound healing and tissue remodeling through their contractile activity. Fibrosis mediated by these cells can initially be a beneficial response that acutely scarifies areas after an infarct to prevent wall rupture. However, during chronic disease states such as heart failure, persistent recruitment and activation of fibroblasts leads to excessive deposition of ECM that results in stiffening and pathological remodeling of the ventricles. During chronic heart disease, cardiomyocytes, immune cells and fibroblasts secrete the cytokine transforming growth factor-TGFβ, which activates fibroblasts and promotes their conversion to myofibroblasts. Manipulation of TGFβ by losartan, which antagonizes angiotensin II (AngII) and aspects of TGFβ signaling, has shown some anti-fibrotic effects in cardiovascular remodeling. Also deletion of Tgfbr1 (type I TGFβ receptor) in cardiomyocytes or a TGFβ blocking antibody reduced the fibrotic response after pressure overload. However heart failure was not improved because deleterious TGFβ signaling in fibroblasts persisted. We therefore utilized a novel fibroblast-specific inducible Cre-expressing mouse line (Periostin-MerCreMer) to examine the canonical (Smad2/3) TGFβ signaling within fibroblasts to determine how these cells and their activation mediate disease in heart failure. Our data indicate that fibroblast-specific deletion of Smad3 but not Smad2 was sufficient to significantly inhibit myocardial fibrosis. Smad2/3 double nulls were also generated and analyzed, as were TGFBR1 and TGFBR2 loxp targeted mice, also crossed with the Postn-MerCreMer knockin allele to achieve specificity in activated fibroblasts.

Abstract 422: Small Molecule and Activated Fibroblast Targeting of the Gβγ-GRK2 Interface After Myocardial Ischemia Attenuates Heart Failure Progression

2017 ◽  
Vol 121 (suppl_1) ◽  
Author(s):  
Joshua G Travers ◽  
Fadia A Kamal ◽  
Inigo Valiente-Alandi ◽  
Michelle L Nieman ◽  
Michelle A Sargent ◽  
...  
Keyword(s):  
Heart Failure ◽  
Myocardial Ischemia ◽  
G Protein ◽  
Small Molecule ◽  
Therapeutic Potential ◽  
Interstitial Fibrosis ◽  
Cardiac Fibroblasts ◽  
Ischemia Reperfusion ◽  
Heart Failure Progression ◽  
Activated Fibroblasts

Cardiac fibroblasts are a critical cell population responsible for myocardial extracellular matrix homeostasis. Upon injury or pathologic stimulation, these cells transform to an activated myofibroblast state and play a fundamental role in myocardial fibrosis and remodeling. Chronic sympathetic overstimulation, a hallmark of heart failure, induces pathologic signaling through G protein βγ subunits and their interaction with G protein-coupled receptor kinase 2 (GRK2). We hypothesized that Gβγ-GRK2 inhibition/ablation after myocardial injury would attenuate pathologic myofibroblast activation and cardiac remodeling. The therapeutic potential of small molecule Gβγ-GRK2 inhibition alone or in combination with activated fibroblast- or myocyte-specific GRK2 ablation, each initiated after myocardial ischemia/reperfusion (I/R) injury, was investigated to evaluate possible salutary effects on post-I/R fibroblast activation, pathologic remodeling and cardiac function. Small molecule Gβγ-GRK2 inhibition initiated one week post-injury was cardioprotective in the I/R model of chronic heart failure, including preservation of cardiac contractility and reduction in cardiac fibrotic remodeling. Systemic small molecule Gβγ-GRK2 inhibition initiated one week post-I/R in cardiomyocyte-restricted GRK2 ablated mice (also post-I/R) demonstrated additional cardioprotection, suggesting a potential protective role beyond the cardiomyocyte. Inducible ablation of GRK2 in activated fibroblasts (i.e. myofibroblasts) post-I/R injury demonstrated significant functional cardioprotection with reduced myofibroblast transformation and fibrosis. Systemic small molecule Gβγ-GRK2 inhibition initiated one week post-I/R provided little to no further protection in mice with ablation of GRK2 in activated fibroblasts alone. Finally, Gβγ-GRK2 inhibition significantly attenuated activation characteristics of failing human cardiac fibroblasts isolated from end stage heart failure patients. These findings suggest a potential therapeutic role for Gβγ-GRK2 inhibition in limiting pathologic myofibroblast activation, interstitial fibrosis and heart failure progression.

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