Thomas Anger

Selective Loss of Fine Tuning of Gq/11 Signaling by RGS2 Protein Exacerbates Cardiomyocyte Hypertrophy

Alterations in cardiac G protein-mediated signaling, most prominently Gq/11 signaling, are centrally involved in hypertrophy and heart failure development. Several RGS proteins that can act as negative regulators of G protein signaling are expressed in the heart, but their functional roles are still poorly understood. RGS expression changes have been described in hypertrophic and failing hearts. In this study, we report a marked decrease in RGS2 (but not other major cardiac RGS proteins (RGS3-RGS5)) that occurs prior to hypertrophy development in different models with enhanced Gq/11 signaling (transgenic expression of activated Gαq* and pressure overload due to aortic constriction). To assess functional consequences of selective down-regulation of endogenous RGS2, we identified targeting sequences for effective RGS2 RNA interference and used lipid-based transfection to achieve uptake of fluorescently labeled RGS2 small interfering RNA in >90% of neonatal and adult ventricular myocytes. Endogenous RGS2 expression was dose-dependently suppressed (up to 90%) with no major change in RGS3-RGS5. RGS2 knockdown increased phenylephrine- and endothelin-1-induced phospholipase Cβ stimulation in both cell types and exacerbated the hypertrophic effect (increase in cell size and radiolabeled protein) in neonatal myocytes, with no major change in Gq/11-mediated ERK1/2, p38, or JNK activation. Taken together, this study demonstrates that endogenous RGS2 exerts functionally important inhibitory restraint on Gq/11-mediated phospholipase Cβ activation and hypertrophy in ventricular myocytes. Our findings point toward a potential pathophysiological role of loss of fine tuning due to selective RGS2 down-regulation in Gq/11-mediated remodeling. Furthermore, this study shows the feasibility of effective RNA interference in cardiomyocytes using lipid-based small interfering RNA transfection.

Interleukin-10 improves left ventricular function in rats with heart failure subsequent to myocardial infarction.

Evidence has shown that pro‐inflammatory cytokines, especially TNF‐α, are involved in the inflammatory response in the remodelling process after myocardial infarction (MI). Although IL‐10, an anti‐inflammatory cytokine, has been shown to antagonize some of the deleterious effects of TNF‐α, little is known about its role in post‐MI left ventricular (LV) dysfunction. The aim of the present study was to investigate whether a therapy with rhIL‐10 could be beneficial in an animal model of post‐MI heart failure (HF).

Atherosclerotic inflammation triggers osteogenic bone transformation in calcified and stenotic human aortic valves: Still a matter of debate

Sclerotic calcification of the aortic valve is a common disease in advanced age. However, pathophysiologic processes leading to valve calcifications are poorly understood. Transformation of atherosclerotic triggers to osteogenic differentiation is controversially discussed and is thought as a trigger of bone transformation in end stage disease. This study focuses on the transcriptional gene-profiling of severe calcified stenotic human aortic valves to clarify the molecular basis of the pathophysiological process. We collected severely calcified and stenotic human aortic valves (CSAV) with (CSAV+, n=10) and without (CSAV-, n=10) at least 4 weeks of statin pre-treatment prior to valve replacement and investigated transcriptional steady-state gene-profiling by using micro array technique and GAPDH-adjusted PCR for confirmation. Results were compared with findings in non-sclerotic aortic valves: C (n=6). Various parameters of inflammation were significantly up regulated as compared to C: eotaxin3, monokine induced by gamma-interferon, vascular adhesion protein-1 (VAP-1), peroxisome proliferative activated receptor-alpha or transforming growth factor beta 1 (TGF beta 1). Except for TGF beta 1 and VAP-1, statin pre-treatment neutralized altered gene expression. Genes of osteogenic bone transformation (tenascin C, bone sialoprotein, Cbfa1, Osteocalcin, Beta-catenin, Sox- and Cyclin-genes) were found unaltered in their expression in both, CSAV- or CSAV+ in comparison to C. This study shows continuing atherosclerotic inflammation on CSAV. Additionally, no evidence of initiated osteoblastic differentiation process was found. Pre-treatment of patients with statins partially neutralized the gene pattern of inflammation on the aortic valves. This suggests that there are potent benefits of statins on early development of inflammation on calcified aortic valves.

Statins stimulate RGS-regulated ERK 1/2 activation in human calcified and stenotic aortic valves

The signal transduction activating extracellular-regulated kinases (ERK) is triggered by G protein-coupled receptors (GPCR). In turn, the GPCR are mediated by G(q) and G(i/o) proteins subjected to regulation of regulators of G protein-mediated signaling (RGS) proteins. This network compiles extracellular growth signals to intracellular targets of sclerosis on calcified and stenotic human aortic valves (CSAV). Statins are known as partial inhibitors of atherosclerotic inflammation on CSAV. This study identifies descriptively the role of statins on RGS subjected ERK activation on CSAV. We collected human CSAV with (n=10, CSAV+) or without (n=10, CSAV-) at least 4 weeks of statin pre-treatment and investigated gene-profiling of RGS proteins, intermediaries and ERK using microarray technique, real-time and semi-quantitative PCR. Human non-calcified aortic valves were controls (n=6, C). Immunohistochemical stainings defined activation of expressed ERK 1/2 on CSAV (+/-) or C. As compared to C, in CSAV- several cardiac expressed RGS proteins were translationally upregulated: RGS1 (2.6 compared C), RGS3 (3.1), RGS5 (2.1) and RGS8 (2.5). In CSAV+, statins neutralized observed RGS expression. ERK expression was found unchanged in all valves: CSAV-, CSAV+ or C. In contrast, immunohistochemically we found enhanced activation of phosphorylated ERK in CSAV+ as compared to CSAV- or control. This study shows reduced RGS protein expression through statins leading to increased activation of ERK on human CSAV. In regard to known studies, the partial therapeutical failure of statins on severe end-stage CSAV is due to the induction of ERK activation which offers the need for more investigation.

Platelets contribute to enhanced MCP-1 levels in patients with chronic heart failure

Background: Increasing scientific data suggest a role for inflammation in chronic heart failure (CHF), but up to now the exact mechanisms are still not clear. Recently, platelets were identified as inducing inflammation partly by releasing cytokines. This new aspect necessitates further studies about the contribution of platelets for the inflammatory setting of CHF. Methods: 50 CHF patients (mean 66.9 (SD 12.6) years, mean EF 22.1% (SD 9.1)) and 25 healthy controls (mean 63.6 (SD 10.2) years) were examined. MCP-1 serum levels were measured via EIA, expression of platelet CD154 by flow cytometry. In in-vitro experiments activated platelets were cocultured with human umbilical vein endothelial cells (HUVEC) in the presence and absence of anti-CD154 antibodies. MCP-1 in the supernatants was measured by EIA. Results: CHF patients showed significantly enhanced MCP-1 levels (median: 191.8; 25th centile: 153.7; 75th centile: 227.1 pg/ml vs median: 101.0; 25th centile: 86.7; 75th centile: 117.5 pg/ml, p<0.001). MCP-1 levels positively correlated with severity of CHF. In the cell coculture model activated platelets were able to significantly induce MCP-1 release from HUVEC in a CD154-dependent manner. Furthermore, CHF patients showed enhanced platelet CD154 expression with a positive correlation with MCP-1 levels. Aspirin therapy had no influence on either CD154 expression or MCP-1 levels. Conclusions: Platelets can contribute to enhanced MCP-1 levels in CHF. MCP-1 is markedly elevated in serum of CHF patients showing a direct correlation with the severity of symptoms and the degree of left ventricular dysfunction. Further studies are required to test whether MCP-1 blocking or sophisticated anti-platelet strategies may represent new therapeutic options in CHF.

Role of endogenous RGS proteins on endothelial ERK 1/2 activation

Endothelial cells are maintaining atherosclerotic signaling mediated by Extracellular Regulated Kinases 1 and 2 (ERK). Signaling gets activated upon stimulation of G protein-coupled receptors mediated by G(q) and G(i/o) proteins subjected to regulation by RGS proteins. The goal of the study was to delineate the specificity of RGS proteins modulating induced ERK phosphorylation. We used stimulated HUVEC, silenced specifically RGS proteins and compared assessed ERK 1/2 activation with immunohistochemical stainings on atherosclerotic plaques. Increased ERK phosphorylation was detected upon stimulation with Phenylephrine (2.6+/-0.1 times over basal), Endothelin-1 (1.8+/-0.2), Dopamine (5.1+/-0.2), TNF (9.8+/-0.7) or IL-4 (3.1+/-0.3). RGS silencing increased activation of ERK 1/2: Phen (RGS3, 5), ET-1 (RGS3, 4), Dopa (RGS3), TNF (RGS2, 3, 4) or IL-4 (RGS2, 3, 4). Immunohistochemically, increased ERK activation was detected on atherosclerotic plaques. This data supports the role of RGS proteins on ERK activation in human atherosclerosis which identifies RGS proteins as new therapeutical targets.

Genpolymorphismus bei der verkalkten Aortenklappenstenose

ZusammenfassungDie kalzifizierte Aortenklappenstenose (AS) ist die häufigste Herzklappenerkrankung in der westlichen Welt. Aufgrund der zunehmenden Lebenserwartung der Bevölkerung wird die Prävalenz der AS deutlich zunehmen. Dieser Anstieg der Erkrankten sowie die Polymorbidität dieser älteren Patienten zwingen dazu, Therapiealternativen zum operativen Aortenklappenersatz zu erforschen und zu etablieren. Derartige alternative Therapiekonzepte gründen ganz wesentlich auf einem verbesserten Verständnis der Pathophysiologie bzw. genetischer Determinanten der einzelnen Subtypen von AS. Durch Aufklärung genetischer Alterationen, die schließlich zur Ausbildung einer AS führen, ist theoretisch die Möglichkeit einer gezielten therapeutischen Beeinflussung dieses Prozesses möglich.Die Literatur beschreibt verschiedene Genpolymorphismen, die zur Ausbildung einer Aortenklappensklerose bzw. -stenose führen können. In diesem Übersichtsartikel werden kongenitale polyvalente Aortenklappenanomalien ohne spezifische genetische Determinanten (gehäuft bei DiGeorge-Syndrom oder Fragile-X-Syndrom), autosomale Aberrationen mit kongenitalen Aortenklappenfehlern (Williams-Beuren-Syndrom, Gaucher-Krankheit, Fallot-Tetralogie, genetische Aberrationen der Chromosomen 2 und 4 sowie die Trisomie 18), X- und Y-chromosomale spezifische Alterationen (z. B. Turner-Syndrom), kongenitale strukturelle Aortenklappenfehler (bikuspide Aortenklappe bei Hand-Herz-Syndromen, tetrakuspide Aortenklappe assoziiert mit dem DiGeorge-Syndrom) und genetische Mutationen spezifischer Zielgene („epidermal growth factor receptor“, NOTCH-1, Elastin, Angiotensin-I-Konversionsenzym, β-Glucocerebrosidase, Interleukin-10, Chemokinrezeptor 5, „connective tissue growth factor“, „transforming growth factor β1“, Vitamin-D-Rezeptor, Östrogenrezeptor-α, Apolipoproteine A1, B und E) unterschieden.Die Bedeutung von Genpolymorphismen für die Entwicklung von verkalkten, stenosierten Aortenklappen tritt erst langsam zutage. Die bisher verfügbaren Daten über genetische Variationen in der Entwicklung einer AS basieren größtenteils auf Untersuchungen von supravalvulären bzw. bikuspiden AS. Erst in jüngerer Zeit erlauben weiterführende molekularbiologische genetische Methoden die breite Analyse der Expression einer Vielzahl von Genen. Diese Genexpressionsanalysen von verkalkten AS verweisen auf pathophysiologische Ähnlichkeiten mit der atherosklerotischen Gefäßinflammation sowie auf eine ossäre Fibrose der Aortenklappe, die schließlich zur hochgradigen AS führen. Derartige Analysen sind derzeit jedoch nicht hinreichend abgeschlossen, um fundierte pathophysiologische Rückschlüsse zu erlauben und hieraus therapeutische Konsequenzen für die Klinik zu ziehen.AbstractIn the Caucasian world calcified and stenosed aortic valves are a common disease. Due to increasing life expectancy prevalence of aortic valve disease will increase dramatically. In order to establish alternative therapeutic approaches to valve replacement, we have to get a better understanding of the pathophysiological process and genetic determinations leading to calcified and stenotic valve disease. Exploring these genetic determinations will open new specific fields of therapeutic modulations of the disease process. In the literature, different gene polymorphisms have been characterized to develop calcifications and further stenosis of the aortic valves.Here, congestive polyvalent aortic valve abnormalities without specific genetic determinations (i. e., DiGeorge syndrome or fragile x syndrome), autosomal inherited alterations leading to congestive aortic valve disease (i. e., Williams-Beuren syndrome, Gaucher’s disease, tetralogy of Fallot, genetic aberrations of chromosomes 2 and 4 as well as trisomy 18), X- and Y-chromosomal specific alterations (i. e., Turner syndrome), congestive structure-based aortic valve disease (i. e., bicuspid aortic valve with regard to handheart syndromes, tetracuspid aortic valve associated with DiGeorge syndrome) and genetic mutations of specific target genes (i. e., epidermal growth factor receptor, NOTCH-1, elastin, angiotensin I conversion enzyme, β-glucocerebrosidase, interleukin-10, chemokine receptor 5, connective tissue growth factor, transforming growth factor β1, vitamin D receptor, estrogen receptor-α, apolipoproteins A1, B, and E) are summarized.The roles of gene polymorphism in the development of calcified and stenosed aortic valve appear slowly in the understanding of the process leading to the valve disease and are mainly based on studies of supravalvular and bicuspid aortic valve stenoses. New molecular biological methods enabling broad gene expression analyses demonstrate the similarity in the pathophysiology of atherosclerotic vessel inflammation, bone formation/fibrosis, with the processes leading to stenosed and calcified aortic valves. Based on to-date knowledge, further analyses have to be done and will improve understanding of the pathophysiological processes with regard to the development of new therapeutic drug targets.

Gene polymorphisms leading to calcified and stenotic aortic valves

ZusammenfassungDie kalzifizierte Aortenklappenstenose (AS) ist die häufigste Herzklappenerkrankung in der westlichen Welt. Aufgrund der zunehmenden Lebenserwartung der Bevölkerung wird die Prävalenz der AS deutlich zunehmen. Dieser Anstieg der Erkrankten sowie die Polymorbidität dieser älteren Patienten zwingen dazu, Therapiealternativen zum operativen Aortenklappenersatz zu erforschen und zu etablieren. Derartige alternative Therapiekonzepte gründen ganz wesentlich auf einem verbesserten Verständnis der Pathophysiologie bzw. genetischer Determinanten der einzelnen Subtypen von AS. Durch Aufklärung genetischer Alterationen, die schließlich zur Ausbildung einer AS führen, ist theoretisch die Möglichkeit einer gezielten therapeutischen Beeinflussung dieses Prozesses möglich.Die Literatur beschreibt verschiedene Genpolymorphismen, die zur Ausbildung einer Aortenklappensklerose bzw. -stenose führen können. In diesem Übersichtsartikel werden kongenitale polyvalente Aortenklappenanomalien ohne spezifische genetische Determinanten (gehäuft bei DiGeorge-Syndrom oder Fragile-X-Syndrom), autosomale Aberrationen mit kongenitalen Aortenklappenfehlern (Williams-Beuren-Syndrom, Gaucher-Krankheit, Fallot-Tetralogie, genetische Aberrationen der Chromosomen 2 und 4 sowie die Trisomie 18), X- und Y-chromosomale spezifische Alterationen (z. B. Turner-Syndrom), kongenitale strukturelle Aortenklappenfehler (bikuspide Aortenklappe bei Hand-Herz-Syndromen, tetrakuspide Aortenklappe assoziiert mit dem DiGeorge-Syndrom) und genetische Mutationen spezifischer Zielgene („epidermal growth factor receptor“, NOTCH-1, Elastin, Angiotensin-I-Konversionsenzym, β-Glucocerebrosidase, Interleukin-10, Chemokinrezeptor 5, „connective tissue growth factor“, „transforming growth factor β1“, Vitamin-D-Rezeptor, Östrogenrezeptor-α, Apolipoproteine A1, B und E) unterschieden.Die Bedeutung von Genpolymorphismen für die Entwicklung von verkalkten, stenosierten Aortenklappen tritt erst langsam zutage. Die bisher verfügbaren Daten über genetische Variationen in der Entwicklung einer AS basieren größtenteils auf Untersuchungen von supravalvulären bzw. bikuspiden AS. Erst in jüngerer Zeit erlauben weiterführende molekularbiologische genetische Methoden die breite Analyse der Expression einer Vielzahl von Genen. Diese Genexpressionsanalysen von verkalkten AS verweisen auf pathophysiologische Ähnlichkeiten mit der atherosklerotischen Gefäßinflammation sowie auf eine ossäre Fibrose der Aortenklappe, die schließlich zur hochgradigen AS führen. Derartige Analysen sind derzeit jedoch nicht hinreichend abgeschlossen, um fundierte pathophysiologische Rückschlüsse zu erlauben und hieraus therapeutische Konsequenzen für die Klinik zu ziehen.AbstractIn the Caucasian world calcified and stenosed aortic valves are a common disease. Due to increasing life expectancy prevalence of aortic valve disease will increase dramatically. In order to establish alternative therapeutic approaches to valve replacement, we have to get a better understanding of the pathophysiological process and genetic determinations leading to calcified and stenotic valve disease. Exploring these genetic determinations will open new specific fields of therapeutic modulations of the disease process. In the literature, different gene polymorphisms have been characterized to develop calcifications and further stenosis of the aortic valves.Here, congestive polyvalent aortic valve abnormalities without specific genetic determinations (i. e., DiGeorge syndrome or fragile x syndrome), autosomal inherited alterations leading to congestive aortic valve disease (i. e., Williams-Beuren syndrome, Gaucher’s disease, tetralogy of Fallot, genetic aberrations of chromosomes 2 and 4 as well as trisomy 18), X- and Y-chromosomal specific alterations (i. e., Turner syndrome), congestive structure-based aortic valve disease (i. e., bicuspid aortic valve with regard to handheart syndromes, tetracuspid aortic valve associated with DiGeorge syndrome) and genetic mutations of specific target genes (i. e., epidermal growth factor receptor, NOTCH-1, elastin, angiotensin I conversion enzyme, β-glucocerebrosidase, interleukin-10, chemokine receptor 5, connective tissue growth factor, transforming growth factor β1, vitamin D receptor, estrogen receptor-α, apolipoproteins A1, B, and E) are summarized.The roles of gene polymorphism in the development of calcified and stenosed aortic valve appear slowly in the understanding of the process leading to the valve disease and are mainly based on studies of supravalvular and bicuspid aortic valve stenoses. New molecular biological methods enabling broad gene expression analyses demonstrate the similarity in the pathophysiology of atherosclerotic vessel inflammation, bone formation/fibrosis, with the processes leading to stenosed and calcified aortic valves. Based on to-date knowledge, further analyses have to be done and will improve understanding of the pathophysiological processes with regard to the development of new therapeutic drug targets.

Genpolymorphismus bei der verkalkten Aortenklappenstenose@@@Gene Polymorphisms Leading to Calcified and Stenotic Aortic Valves

ZusammenfassungDie kalzifizierte Aortenklappenstenose (AS) ist die häufigste Herzklappenerkrankung in der westlichen Welt. Aufgrund der zunehmenden Lebenserwartung der Bevölkerung wird die Prävalenz der AS deutlich zunehmen. Dieser Anstieg der Erkrankten sowie die Polymorbidität dieser älteren Patienten zwingen dazu, Therapiealternativen zum operativen Aortenklappenersatz zu erforschen und zu etablieren. Derartige alternative Therapiekonzepte gründen ganz wesentlich auf einem verbesserten Verständnis der Pathophysiologie bzw. genetischer Determinanten der einzelnen Subtypen von AS. Durch Aufklärung genetischer Alterationen, die schließlich zur Ausbildung einer AS führen, ist theoretisch die Möglichkeit einer gezielten therapeutischen Beeinflussung dieses Prozesses möglich.Die Literatur beschreibt verschiedene Genpolymorphismen, die zur Ausbildung einer Aortenklappensklerose bzw. -stenose führen können. In diesem Übersichtsartikel werden kongenitale polyvalente Aortenklappenanomalien ohne spezifische genetische Determinanten (gehäuft bei DiGeorge-Syndrom oder Fragile-X-Syndrom), autosomale Aberrationen mit kongenitalen Aortenklappenfehlern (Williams-Beuren-Syndrom, Gaucher-Krankheit, Fallot-Tetralogie, genetische Aberrationen der Chromosomen 2 und 4 sowie die Trisomie 18), X- und Y-chromosomale spezifische Alterationen (z. B. Turner-Syndrom), kongenitale strukturelle Aortenklappenfehler (bikuspide Aortenklappe bei Hand-Herz-Syndromen, tetrakuspide Aortenklappe assoziiert mit dem DiGeorge-Syndrom) und genetische Mutationen spezifischer Zielgene („epidermal growth factor receptor“, NOTCH-1, Elastin, Angiotensin-I-Konversionsenzym, β-Glucocerebrosidase, Interleukin-10, Chemokinrezeptor 5, „connective tissue growth factor“, „transforming growth factor β1“, Vitamin-D-Rezeptor, Östrogenrezeptor-α, Apolipoproteine A1, B und E) unterschieden.Die Bedeutung von Genpolymorphismen für die Entwicklung von verkalkten, stenosierten Aortenklappen tritt erst langsam zutage. Die bisher verfügbaren Daten über genetische Variationen in der Entwicklung einer AS basieren größtenteils auf Untersuchungen von supravalvulären bzw. bikuspiden AS. Erst in jüngerer Zeit erlauben weiterführende molekularbiologische genetische Methoden die breite Analyse der Expression einer Vielzahl von Genen. Diese Genexpressionsanalysen von verkalkten AS verweisen auf pathophysiologische Ähnlichkeiten mit der atherosklerotischen Gefäßinflammation sowie auf eine ossäre Fibrose der Aortenklappe, die schließlich zur hochgradigen AS führen. Derartige Analysen sind derzeit jedoch nicht hinreichend abgeschlossen, um fundierte pathophysiologische Rückschlüsse zu erlauben und hieraus therapeutische Konsequenzen für die Klinik zu ziehen.AbstractIn the Caucasian world calcified and stenosed aortic valves are a common disease. Due to increasing life expectancy prevalence of aortic valve disease will increase dramatically. In order to establish alternative therapeutic approaches to valve replacement, we have to get a better understanding of the pathophysiological process and genetic determinations leading to calcified and stenotic valve disease. Exploring these genetic determinations will open new specific fields of therapeutic modulations of the disease process. In the literature, different gene polymorphisms have been characterized to develop calcifications and further stenosis of the aortic valves.Here, congestive polyvalent aortic valve abnormalities without specific genetic determinations (i. e., DiGeorge syndrome or fragile x syndrome), autosomal inherited alterations leading to congestive aortic valve disease (i. e., Williams-Beuren syndrome, Gaucher’s disease, tetralogy of Fallot, genetic aberrations of chromosomes 2 and 4 as well as trisomy 18), X- and Y-chromosomal specific alterations (i. e., Turner syndrome), congestive structure-based aortic valve disease (i. e., bicuspid aortic valve with regard to handheart syndromes, tetracuspid aortic valve associated with DiGeorge syndrome) and genetic mutations of specific target genes (i. e., epidermal growth factor receptor, NOTCH-1, elastin, angiotensin I conversion enzyme, β-glucocerebrosidase, interleukin-10, chemokine receptor 5, connective tissue growth factor, transforming growth factor β1, vitamin D receptor, estrogen receptor-α, apolipoproteins A1, B, and E) are summarized.The roles of gene polymorphism in the development of calcified and stenosed aortic valve appear slowly in the understanding of the process leading to the valve disease and are mainly based on studies of supravalvular and bicuspid aortic valve stenoses. New molecular biological methods enabling broad gene expression analyses demonstrate the similarity in the pathophysiology of atherosclerotic vessel inflammation, bone formation/fibrosis, with the processes leading to stenosed and calcified aortic valves. Based on to-date knowledge, further analyses have to be done and will improve understanding of the pathophysiological processes with regard to the development of new therapeutic drug targets.