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calmodulin-dependent protein kinase II activates apoptosis signal-regulating kinase 1 and nuclear factor-kappaB to induce cardiomyocyte hypertrophy
S178
Journal of Cardiac Failure Vol. 10 No. 5 Suppl. 2004
O-093
O-095
Leptin Induces Elongation of Cardiac Myocytes Through the Activation of JAK2/STAT3 Cascade ABE YUKIKO1, ONO KOH1, KAWAMURA TERUHISA1, SHIMAZU AKIRA1, HASEGAWA KOJI1, MORIMOTO TATSUYA2, KITA TORU2 1 Division of Translational Research, Kyoto Medical Center, National Hospital Organization, Kyoto, Japan, 2Department of Cardiovascular Medicine, Kyoto University, Kyoto, Japan
The Role of Phosphoinositie 3-kinase in Thyroid Hormone Induced Cardiac Hypertrophy KOSUGI RIE, SHIOI TETSUO, MAEDA KAYO, IZUMI TOHRU Kitasato University School of Medicine, Sagamihara, Japan
Leptin, one of cytokines, secreted from the fat and acts mainly on the hypothalamic leptin receptors. Subsequent studies demonstrate that leptin receptors widely distributed in various tissues including the heart. While increased plasma leptin levels have been reported in patients with congestive heart failure, direct effects of leptin on cardiac structure and function are unknown. To begin to address this question, we exposed primary cardiac myocytes from neonatal rats to leptin at the concentration of 0, 5, 50, and 500 ng/ml for 48 hours. Treatment of cardiomyocytes with leptin results in concentration dependent increase in cell surface area. We found that leptin significantly increased the long axis length of myocytes (10.9 ⫾ 3.9%: 50ng/ml, p ⬍ 0.05; 13.6 ⫾ 4.3%: 500ng/ml, p ⬍ 0.05), but not the short one. Western blotting and electromobility shift assays revealed no activation of MAP kinases including ERK, p38MAPK, and JNK. However, by immunohistochemical analysis, we showed that leptin treatment caused translocation of STAT3 into the nuclei in cardiac myocytes. Furthermore, leptin caused phophorylation of STAT3 as early as 5 minutes after the treatment and enhanced its DNA binding activity. Administration of a JAK2 inhibitor, AG490 (1microM), completely inhibited these effects by leptin. These results suggest that leptin induces elongation of cardiac myocytes and that this effect is mediated, in part, through the activation of JAK2/ STAT3 cascade.
Purpose: Thyroid hormone (T4) induces physiological cardiac hypertrophy in animals. Activation of phosphoinositide 3-kinase (PI3K) is shown to be necessary and sufficient to promote physiological hypertrophy in mice. We assessed the hypothesis that PI3K is involved in T4 induced cardiac hypertrophy. Method: To examine if T4 activates effectors of PI3K, T4 or saline was intraperitoneally administered to mice. The mice were sacrificed 1, 4, 8, or 24 hours after the injection. The amount of phosphorylated Akt, p70 ribosomal S6kinase1 (S6K1), ribosomal S6 Protein (S6) in the heart tissue was analyzed by Western blotting. To examine if PI3K is necessary for T4 induced cardiac hypertrophy, T4 was daily administered to transgenic mice expressing dominant-negative form of PI3K in the heart (dnPI3K mice) or non-transgenic mice (NTg mice) for 14 days. After the echocardiographic examination, the mice were sacrificed for analysis. Result: The amount of phosphorylated Akt was increased at 1, 4, and 8 hours after T4 injection. The S6K1 phosphorylation increased at 4 and 8 hours. The S6 phosphorylation increased at 8 hours. Heart weight/body weight of T4 treated NTg mice was increase by 27% compared with the saline treated NTg mice. In contrast, T4 treated dnPI3K mice was increased by 9% compared with saline treated dnPI3K mice. Conclusion: Thyroid hormone induced physiological cardiac hypertrophy in a PI3K dependent manner.
O-094
O-096
Ca2ⴙ/Calmodulin-dependent Protein Kinase II Activates Apoptosis Signal-Regulating Kinase 1 and Nuclear Factor-kappaB to Induce Cardiomyocyte Hypertrophy KASHIWASE KAZUNORI, OTSU KINYA, YAMAGUCHI OSAMU, HIKOSO SYUNGO, TAKEDA TOSHIHIRO, WATANABE TETSUYA, TANIIKE MASAYUKI, ASAHI MICHIO, NISHIDA KAZUHIKO, HORI MASATSUGU Department of Internal Medicine and Therapeutics, Osaka University, Graduate School of Medicine, Osaka, Japan
Chronic Effect of Co-Administration of Endopeptidase Inhibitor and Adrenomedullin (AM) in Heart Failure (HF) in Rats
Ca2⫹/calmodulin-dependent protein kinase (CaMK) is an important molecule in cardiomyocyte hypertrophy. We previously showed that the activation of apoptosis signal-regulating kinase 1 (ASK1) or its transcription factor NF-kappaB is sufficient for cardiomyocyte hypertrophy. Recently, it was reported that in C. elegans, UNC-43, a homologue to CaMKII, activates NSY-1, which is a homologue of mammalian ASK1. We hypothesized that ASK1-NF-kappaB signaling pathway was a downstream target of CaMKII. In vitro kinase assay indicates that infection of isolated neonatal cardiomyocytes with adenoviral vector expressing CaMKIIdelta3 (AdCaMKIIdelta3) induced the activation of ASK1, while KN93, an inhibitor of CaMKII, inhibited phenylephrine-induced ASK1 activation. Overexpression of CaMKIIdelta3 induced hypertrophic responses, including increases in protein synthesis, atrial natriuretic factor production and the enhancement of sarcomeric organization. KN93 inhibited these hypertrophic responses induced by phenylephrine. Infection of cardiomyocytes with an adenoviral vector expressing a dominant negative mutant of ASK1 (AdASK(KM)) inhibited the CaMKIIdelta3-induced hypertrophic responses. To evaluate NF-kappaB activation, we measured the activity of kappaB-dependent reporter gene assay and IkappaBalfa degradation by Western blotting. Overexpression of CaMKIIdelta3 increased the luciferase activity and induced IkappaBalfa degradation. Coinfection of AdCaMKIIdelta3 with AdASK (KM) and preincubation with KN93 attenuated CaMKIIdelta3- and phenylephrine-induced NF-kappaB activation, respectively. Expression of a degradation resistant mutant of IkappaBalfa inhibited CaMKIIdelta3-induced hypertrophic responses. These results indicate that CaMKIIdelta3 induces cardiomyocyte hypertrophy mediated through ASK1-NF-kappaB signal transduction pathway.
ISHIMURA KIMIHIKO, NISHIKIMI TOSHIO, MORI YOUSUKE, ISHIKAWA YAYOI, TADOKORO KAZUYOSHI, AKIMOTO KAZUMI, MATHUOKA HIROAKI Department of Hypertention and Cardiorenal Medicine, Dokkyo University School of Medicine, Tochigi, Japan Background: We have recently reported that chronic AM administration has beneficial effects in HF. This study sought to examine the effect of combined endopeptidase inhibition and AM in HF in rats, because AM is metabolized partly via neutral endopeptidase pathway. Methods and Results: Dahl salt-sensitive rats (DS) were randomly divided into three groups, omapatrilat group (35 mg/kg/day; n ⫽ 16), omapatrilat⫹ AM (500 ng/h; n ⫽ 16) group, and untreated group (n ⫽ 16). We assessed HF after 7 weeks treatment. Results: Omapatrilat reduced left ventricular weight (LVW), blood pressure, LVEDP, and right ventricular systolic pressure (RVSP) compared with untreated DS. Plasma atrial natriuretic peptide (ANP), and AM were decreased, but renin and aldosterone did not change. In addition, omaparilat decreased mRNA levels of ANP, AM, TGF and collagen I and III in the left ventricle. Histological examination also decreased perifibrosis score. Although there were no differences in blood pressure between omapatrilat and omapatrilat⫹AM groups, omapatrilat⫹AM further decreased LVW, LVEDP, RVSP, and mRNA expression of TGF and collagen I and III. Interestingly, omapatrilat⫹AM further reduced mRNA levels of ANP and AM, there were no differences in plasma ANP or AM levels between the two groups. Conclusion: These results suggest that cotreatment with AM and omapatrilat may be a new therapeutic strategy to the treatment of HF, partly mediated via the inhibition of metabolism of ANP or AM.
Journal of Cardiac Failure Vol. 10 No. 5 Suppl. 2004
O-093
O-095
Leptin Induces Elongation of Cardiac Myocytes Through the Activation of JAK2/STAT3 Cascade ABE YUKIKO1, ONO KOH1, KAWAMURA TERUHISA1, SHIMAZU AKIRA1, HASEGAWA KOJI1, MORIMOTO TATSUYA2, KITA TORU2 1 Division of Translational Research, Kyoto Medical Center, National Hospital Organization, Kyoto, Japan, 2Department of Cardiovascular Medicine, Kyoto University, Kyoto, Japan
The Role of Phosphoinositie 3-kinase in Thyroid Hormone Induced Cardiac Hypertrophy KOSUGI RIE, SHIOI TETSUO, MAEDA KAYO, IZUMI TOHRU Kitasato University School of Medicine, Sagamihara, Japan
Leptin, one of cytokines, secreted from the fat and acts mainly on the hypothalamic leptin receptors. Subsequent studies demonstrate that leptin receptors widely distributed in various tissues including the heart. While increased plasma leptin levels have been reported in patients with congestive heart failure, direct effects of leptin on cardiac structure and function are unknown. To begin to address this question, we exposed primary cardiac myocytes from neonatal rats to leptin at the concentration of 0, 5, 50, and 500 ng/ml for 48 hours. Treatment of cardiomyocytes with leptin results in concentration dependent increase in cell surface area. We found that leptin significantly increased the long axis length of myocytes (10.9 ⫾ 3.9%: 50ng/ml, p ⬍ 0.05; 13.6 ⫾ 4.3%: 500ng/ml, p ⬍ 0.05), but not the short one. Western blotting and electromobility shift assays revealed no activation of MAP kinases including ERK, p38MAPK, and JNK. However, by immunohistochemical analysis, we showed that leptin treatment caused translocation of STAT3 into the nuclei in cardiac myocytes. Furthermore, leptin caused phophorylation of STAT3 as early as 5 minutes after the treatment and enhanced its DNA binding activity. Administration of a JAK2 inhibitor, AG490 (1microM), completely inhibited these effects by leptin. These results suggest that leptin induces elongation of cardiac myocytes and that this effect is mediated, in part, through the activation of JAK2/ STAT3 cascade.
Purpose: Thyroid hormone (T4) induces physiological cardiac hypertrophy in animals. Activation of phosphoinositide 3-kinase (PI3K) is shown to be necessary and sufficient to promote physiological hypertrophy in mice. We assessed the hypothesis that PI3K is involved in T4 induced cardiac hypertrophy. Method: To examine if T4 activates effectors of PI3K, T4 or saline was intraperitoneally administered to mice. The mice were sacrificed 1, 4, 8, or 24 hours after the injection. The amount of phosphorylated Akt, p70 ribosomal S6kinase1 (S6K1), ribosomal S6 Protein (S6) in the heart tissue was analyzed by Western blotting. To examine if PI3K is necessary for T4 induced cardiac hypertrophy, T4 was daily administered to transgenic mice expressing dominant-negative form of PI3K in the heart (dnPI3K mice) or non-transgenic mice (NTg mice) for 14 days. After the echocardiographic examination, the mice were sacrificed for analysis. Result: The amount of phosphorylated Akt was increased at 1, 4, and 8 hours after T4 injection. The S6K1 phosphorylation increased at 4 and 8 hours. The S6 phosphorylation increased at 8 hours. Heart weight/body weight of T4 treated NTg mice was increase by 27% compared with the saline treated NTg mice. In contrast, T4 treated dnPI3K mice was increased by 9% compared with saline treated dnPI3K mice. Conclusion: Thyroid hormone induced physiological cardiac hypertrophy in a PI3K dependent manner.
O-094
O-096
Ca2ⴙ/Calmodulin-dependent Protein Kinase II Activates Apoptosis Signal-Regulating Kinase 1 and Nuclear Factor-kappaB to Induce Cardiomyocyte Hypertrophy KASHIWASE KAZUNORI, OTSU KINYA, YAMAGUCHI OSAMU, HIKOSO SYUNGO, TAKEDA TOSHIHIRO, WATANABE TETSUYA, TANIIKE MASAYUKI, ASAHI MICHIO, NISHIDA KAZUHIKO, HORI MASATSUGU Department of Internal Medicine and Therapeutics, Osaka University, Graduate School of Medicine, Osaka, Japan
Chronic Effect of Co-Administration of Endopeptidase Inhibitor and Adrenomedullin (AM) in Heart Failure (HF) in Rats
Ca2⫹/calmodulin-dependent protein kinase (CaMK) is an important molecule in cardiomyocyte hypertrophy. We previously showed that the activation of apoptosis signal-regulating kinase 1 (ASK1) or its transcription factor NF-kappaB is sufficient for cardiomyocyte hypertrophy. Recently, it was reported that in C. elegans, UNC-43, a homologue to CaMKII, activates NSY-1, which is a homologue of mammalian ASK1. We hypothesized that ASK1-NF-kappaB signaling pathway was a downstream target of CaMKII. In vitro kinase assay indicates that infection of isolated neonatal cardiomyocytes with adenoviral vector expressing CaMKIIdelta3 (AdCaMKIIdelta3) induced the activation of ASK1, while KN93, an inhibitor of CaMKII, inhibited phenylephrine-induced ASK1 activation. Overexpression of CaMKIIdelta3 induced hypertrophic responses, including increases in protein synthesis, atrial natriuretic factor production and the enhancement of sarcomeric organization. KN93 inhibited these hypertrophic responses induced by phenylephrine. Infection of cardiomyocytes with an adenoviral vector expressing a dominant negative mutant of ASK1 (AdASK(KM)) inhibited the CaMKIIdelta3-induced hypertrophic responses. To evaluate NF-kappaB activation, we measured the activity of kappaB-dependent reporter gene assay and IkappaBalfa degradation by Western blotting. Overexpression of CaMKIIdelta3 increased the luciferase activity and induced IkappaBalfa degradation. Coinfection of AdCaMKIIdelta3 with AdASK (KM) and preincubation with KN93 attenuated CaMKIIdelta3- and phenylephrine-induced NF-kappaB activation, respectively. Expression of a degradation resistant mutant of IkappaBalfa inhibited CaMKIIdelta3-induced hypertrophic responses. These results indicate that CaMKIIdelta3 induces cardiomyocyte hypertrophy mediated through ASK1-NF-kappaB signal transduction pathway.
ISHIMURA KIMIHIKO, NISHIKIMI TOSHIO, MORI YOUSUKE, ISHIKAWA YAYOI, TADOKORO KAZUYOSHI, AKIMOTO KAZUMI, MATHUOKA HIROAKI Department of Hypertention and Cardiorenal Medicine, Dokkyo University School of Medicine, Tochigi, Japan Background: We have recently reported that chronic AM administration has beneficial effects in HF. This study sought to examine the effect of combined endopeptidase inhibition and AM in HF in rats, because AM is metabolized partly via neutral endopeptidase pathway. Methods and Results: Dahl salt-sensitive rats (DS) were randomly divided into three groups, omapatrilat group (35 mg/kg/day; n ⫽ 16), omapatrilat⫹ AM (500 ng/h; n ⫽ 16) group, and untreated group (n ⫽ 16). We assessed HF after 7 weeks treatment. Results: Omapatrilat reduced left ventricular weight (LVW), blood pressure, LVEDP, and right ventricular systolic pressure (RVSP) compared with untreated DS. Plasma atrial natriuretic peptide (ANP), and AM were decreased, but renin and aldosterone did not change. In addition, omaparilat decreased mRNA levels of ANP, AM, TGF and collagen I and III in the left ventricle. Histological examination also decreased perifibrosis score. Although there were no differences in blood pressure between omapatrilat and omapatrilat⫹AM groups, omapatrilat⫹AM further decreased LVW, LVEDP, RVSP, and mRNA expression of TGF and collagen I and III. Interestingly, omapatrilat⫹AM further reduced mRNA levels of ANP and AM, there were no differences in plasma ANP or AM levels between the two groups. Conclusion: These results suggest that cotreatment with AM and omapatrilat may be a new therapeutic strategy to the treatment of HF, partly mediated via the inhibition of metabolism of ANP or AM.