scholarly journals Synus node dysfunction in heart failure is characterized by reduced CaMKII signaling

2021 ◽  
Vol 154 (9) ◽  
Author(s):  
Jian-Bin Xue ◽  
Almudena Val-Blasco ◽  
Moran Davoodi ◽  
Susana Gómez ◽  
Yael Yaniv ◽  
...  
Keyword(s):  
Heart Failure ◽  
Ventricular Arrhythmias ◽  
Sinoatrial Node ◽  
Heart Rhythm ◽  
Pacemaker Activity ◽  
Transverse Aortic Constriction ◽  
Aortic Constriction ◽  
Death Rates ◽  
Pump Failure ◽  
Camkii Activation

Heart failure (HF) is a complex syndrome in which death rates are over 50%. The main cause of death among HF patients is pump failure and ventricular arrhythmias, but severe bradycardia is also a common cause of sudden cardiac death, pointing to sinoatrial node (SAN) dysfunction. SAN pacemaker activity is regulated by voltage-clock and Ca2+-clock mechanisms and, although voltage-clock dysfunction in SAN has been largely proved in HF, Ca2+-clock dysfunction mechanisms in SAN remains undiscovered. Here, we used a HF model in mice with transverse aortic constriction (TAC) and using telemetry saw slower heart rhythm under autonomic nervous system blockade. Then, using confocal microscopy we analyzed Ca2+ handling in HF SAN tissue and found that intracellular Ca2+ transient rates were slower in addition to less frequency of Ca2+ sparks than in SHAM SAN tissue. Next, we studied protein expression of key excitation–contraction coupling proteins and found reduced expression of the Na+/Ca2+ exchanger and reduced phosphorylated status of ryanodine receptor and phospholamban in the CaMKII sites for the SAN in TAC mice. Finally, the application of the CaMKII inhibitor KN93 caused less effect in slowing the Ca2+ transient rates in HF SAN tissue, confirming the reduced CaMKII activation. In conclusion, our data demonstrate a reduction in CaMKII activation in the Ca2+-clock function of the SAN tissue in a mouse model of HF.

scholarly journals Synus node dysfunction in heart failure is characterized by reduced CaMKII signaling

2021 ◽  
Vol 154 (9) ◽  
Author(s):  
Jian-Bin Xue ◽  
Almudena Val-Blasco ◽  
Moran Davoodi ◽  
Susana Gómez ◽  
Yael Yaniv ◽  
...  
Keyword(s):  
Heart Failure ◽  
Ventricular Arrhythmias ◽  
Causes Of Death ◽  
Sinoatrial Node ◽  
Heart Rhythm ◽  
Pacemaker Activity ◽  
Transverse Aortic Constriction ◽  
Aortic Constriction ◽  
Pump Failure ◽  
Camkii Activation

Heart failure (HF) is a complex syndrome in which death rates are >50%. The main causes of death among HF patients are pump failure and ventricular arrhythmias, but severe bradycardia is also a common cause of sudden cardiac death, pointing to sinoatrial node (SAN) dysfunction. SAN pacemaker activity is regulated by voltage-clock and Ca2+-clock mechanisms and, although voltage-clock dysfunction in SAN has been largely proved in HF, Ca2+-clock dysfunction mechanisms in SAN remains unraveled. Here, we used an HF model in mice with transverse aortic constriction (TAC) and, using telemetry, saw slower heart rhythm under autonomic nervous system blockade. Then, by confocal microscopy, we analyzed Ca2+ handling in HF SAN tissue and found that intracellular Ca2+ transients rate were slower together with less frequency of Ca2+ sparks than in SHAM SAN tissue. Next, we studied protein expression of key excitation–contraction coupling proteins and found reduced expression of the Na+/Ca2+ exchanger and reduced phosphorylated status of ryanodine receptor and phospholamban in the CaMKII sites for the SAN in TAC mice. Finally, the application of the CaMKII inhibitor, KN93, caused less effect in slowing the Ca2+ transient rates in HF SAN tissue, confirming the reduced CaMKII activation. In conclusion, our data demonstrates a reduction in CaMKII activation in the Ca2+-clock function of the SAN tissue in a mouse model of HF.

scholarly journals Bone Morphogenetic Protein 9 Reduces Cardiac Fibrosis and Improves Cardiac Function in Heart Failure

Circulation ◽  
2018 ◽  
Vol 138 (5) ◽  
pp. 513-526 ◽  
Author(s):  
Kevin J. Morine ◽  
Xiaoying Qiao ◽  
Sam York ◽  
Peter S. Natov ◽  
Vikram Paruchuri ◽  
...  
Keyword(s):  
Heart Failure ◽  
Cardiac Fibrosis ◽  
Cardiac Fibroblasts ◽  
Human Subjects ◽  
Lv Function ◽  
Transverse Aortic Constriction ◽  
Aortic Constriction ◽  
Bone Morphogenetic Protein 9 ◽  
Human Cardiac Fibroblasts ◽  
Tgf Β1

Background: Heart failure is a growing cause of morbidity and mortality worldwide. Transforming growth factor beta (TGF-β1) promotes cardiac fibrosis, but also activates counterregulatory pathways that serve to regulate TGF-β1 activity in heart failure. Bone morphogenetic protein 9 (BMP9) is a member of the TGFβ family of cytokines and signals via the downstream effector protein Smad1. Endoglin is a TGFβ coreceptor that promotes TGF-β1 signaling via Smad3 and binds BMP9 with high affinity. We hypothesized that BMP9 limits cardiac fibrosis by activating Smad1 and attenuating Smad3, and, furthermore, that neutralizing endoglin activity promotes BMP9 activity. Methods: We examined BMP9 expression and signaling in human cardiac fibroblasts and human subjects with heart failure. We used the transverse aortic constriction–induced model of heart failure to evaluate the functional effect of BMP9 signaling on cardiac remodeling. Results: BMP9 expression is increased in the circulation and left ventricle (LV) of human subjects with heart failure and is expressed by cardiac fibroblasts. Next, we observed that BMP9 attenuates type I collagen synthesis in human cardiac fibroblasts using recombinant human BMP9 and a small interfering RNA approach. In BMP9 –/– mice subjected to transverse aortic constriction, loss of BMP9 activity promotes cardiac fibrosis, impairs LV function, and increases LV levels of phosphorylated Smad3 (pSmad3), not pSmad1. In contrast, treatment of wild-type mice subjected to transverse aortic constriction with recombinant BMP9 limits progression of cardiac fibrosis, improves LV function, enhances myocardial capillary density, and increases LV levels of pSmad1, not pSmad3 in comparison with vehicle-treated controls. Because endoglin binds BMP9 with high affinity, we explored the effect of reduced endoglin activity on BMP9 activity. Neutralizing endoglin activity in human cardiac fibroblasts or in wild-type mice subjected to transverse aortic constriction–induced heart failure limits collagen production, increases BMP9 protein levels, and increases levels of pSmad1, not pSmad3. Conclusions: Our results identify a novel functional role for BMP9 as an endogenous inhibitor of cardiac fibrosis attributable to LV pressure overload and further show that treatment with either recombinant BMP9 or disruption of endoglin activity promotes BMP9 activity and limits cardiac fibrosis in heart failure, thereby providing potentially novel therapeutic approaches for patients with heart failure.

scholarly journals Modeling heart failure risk in diabetes and kidney disease: limitations and potential applications of transverse aortic constriction in high-fat-fed mice

2018 ◽  
Vol 314 (6) ◽  
pp. R858-R869 ◽  
Author(s):  
Wei Sheng Tan ◽  
Thomas P. Mullins ◽  
Melanie Flint ◽  
Sarah L. Walton ◽  
Helle Bielefeldt-Ohmann ◽  
...  
Keyword(s):  
Heart Failure ◽  
Kidney Disease ◽  
Left Ventricular ◽  
Cardiomyocyte Hypertrophy ◽  
Transverse Aortic Constriction ◽  
High Fat ◽  
Aortic Constriction ◽  
Failure Risk ◽  
Cardiovascular Prognosis ◽  
Fat Feeding

There is an increased incidence of heart failure in individuals with diabetes mellitus (DM). The coexistence of kidney disease in DM exacerbates the cardiovascular prognosis. Researchers have attempted to combine the critical features of heart failure, using transverse aortic constriction, with DM in mice, but variable findings have been reported. Furthermore, kidney outcomes have not been assessed in this setting; thus its utility as a model of heart failure in DM and kidney disease is unknown. We generated a mouse model of obesity, hyperglycemia, and mild kidney pathology by feeding male C57BL/6J mice a high-fat diet (HFD). Cardiac pressure overload was surgically induced using transverse aortic constriction (TAC). Normal diet (ND) and sham controls were included. Heart failure risk factors were evident at 8-wk post-TAC, including increased left ventricular mass (+49% in ND and +35% in HFD), cardiomyocyte hypertrophy (+40% in ND and +28% in HFD), and interstitial and perivascular fibrosis (Masson’s trichrome and picrosirius red positivity). High-fat feeding did not exacerbate the TAC-induced cardiac outcomes. At 11 wk post-TAC in a separate mouse cohort, echocardiography revealed reduced left ventricular size and increased left ventricular wall thickness, the latter being evident in ND mice only. Systolic function was preserved in the TAC mice and was similar between ND and HFD. Thus combined high-fat feeding and TAC in mice did not model the increased incidence of heart failure in DM patients. This model, however, may mimic the better cardiovascular prognosis seen in overweight and obese heart failure patients.

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