scholarly journals ERK1/2 inhibition promotes robust myotube growth via CaMKII activation resulting in myoblast-to-myotube fusion

2021 ◽  
Vol 56 (24) ◽  
pp. 3349-3363.e6
Author(s):  
Tamar Eigler ◽  
Giulia Zarfati ◽  
Emmanuel Amzallag ◽  
Sansrity Sinha ◽  
Nadav Segev ◽  
...  
Keyword(s):  
Camkii Activation

scholarly journals Cardiac CaMKII activation promotes rapid translocation to its extra-dyadic targets

2018 ◽  
Vol 125 ◽  
pp. 18-28 ◽  
Author(s):  
Brent M. Wood ◽  
Mitchell Simon ◽  
Samuel Galice ◽  
Chidera C. Alim ◽  
Maura Ferrero ◽  
...  
Keyword(s):  
Camkii Activation

scholarly journals Mitochondrial Contributions in the Genesis of Delayed Afterdepolarizations in Ventricular Myocytes

2021 ◽  
Vol 12 ◽  
Author(s):  
Vikas Pandey ◽  
Lai-Hua Xie ◽  
Zhilin Qu ◽  
Zhen Song
Keyword(s):  
Signaling Pathways ◽  
Energy Demand ◽  
Mitochondrial Permeability Transition ◽  
Ryanodine Receptors ◽  
Critical Role ◽  
Permeability Transition ◽  
Atp Depletion ◽  
Mitochondrial Depolarization ◽  
Delayed Afterdepolarizations ◽  
Camkii Activation

Mitochondria fulfill the cell’s energy demand and affect the intracellular calcium (Ca2+) dynamics via direct Ca2+ exchange, the redox effect of reactive oxygen species (ROS) on Ca2+ handling proteins, and other signaling pathways. Recent experimental evidence indicates that mitochondrial depolarization promotes arrhythmogenic delayed afterdepolarizations (DADs) in cardiac myocytes. However, the nonlinear interactions among the Ca2+ signaling pathways, ROS, and oxidized Ca2+/calmodulin-dependent protein kinase II (CaMKII) pathways make it difficult to reveal the mechanisms. Here, we use a recently developed spatiotemporal ventricular myocyte computer model, which consists of a 3-dimensional network of Ca2+ release units (CRUs) intertwined with mitochondria and integrates mitochondrial Ca2+ signaling and other complex signaling pathways, to study the mitochondrial regulation of DADs. With a systematic investigation of the synergistic or competing factors that affect the occurrence of Ca2+ waves and DADs during mitochondrial depolarization, we find that the direct redox effect of ROS on ryanodine receptors (RyRs) plays a critical role in promoting Ca2+ waves and DADs under the acute effect of mitochondrial depolarization. Furthermore, the upregulation of mitochondrial Ca2+ uniporter can promote DADs through Ca2+-dependent opening of mitochondrial permeability transition pores (mPTPs). Also, due to much slower dynamics than Ca2+ cycling and ROS, oxidized CaMKII activation and the cytosolic ATP do not appear to significantly impact the genesis of DADs during the acute phase of mitochondrial depolarization. However, under chronic conditions, ATP depletion suppresses and enhanced CaMKII activation promotes Ca2+ waves and DADs.

Abstract 13837: Adrenergic Receptors β2 and β3 Transduce Differential Signals in Cardiac Fibroblasts

Circulation ◽  
2015 ◽  
Vol 132 (suppl_3) ◽  
Author(s):  
Kota Tonegawa ◽  
Hiroyuki Nakayama ◽  
Hiromi Igarashi ◽  
Sachi Matsunami ◽  
Nao Hayamizu ◽  
...  
Keyword(s):  
Heart Failure ◽  
Cardiac Fibrosis ◽  
Cardiac Fibroblasts ◽  
Cell Types ◽  
Neonatal Rat ◽  
Rt Pcr ◽  
Β Blocker ◽  
Selective Agonists ◽  
Selective Blocker ◽  
Camkii Activation

Background: Cardiac fibroblasts (CFs) are the most prevalent cell types in heart and play important roles in cardiac remodeling. While the roles of β-adrenergic receptor (βAR) signaling in cardiomyocytes (CMs) are well characterized, those in CFs remain to be elusive due to lack of convenient method to assess those signaling. There are three subtypes of, βAR β1, β2, β3 and β2AR is reported to be expressed in CFs by which enhances cell proliferation and production of inflammatory cytokines. Clinical efficacy of non-selective β blocker carvedilol for heart failure (HF) surpasses that of β1 selective blocker metoprolol, suggesting critical roles of β2 and β3AR in the pathogenesis of HF. Objective: To elucidate the signaling downstream βARs in CFs in heart. Methods and Results: Caveolae is an important microdomain for signal transduction, such as βAR, present in CMs or CFs. To elucidate βAR signaling of caveolae in CFs, we generated a fusion protein composed of phospholamban (PLN) and caveolin3 (Cav3) representing PKA activation as phosphorylation at S16 of PLN and CaMKII as that at T17 in caveolae. Thus, activation of PKA or CaMKII is detectable by anti-phospho-S16 or T17 antibody, respectively. In neonatal rat CFs (NRCFs) infected PLN-Cav3 adenovirus, stimulation by isoproterenol (ISO) led to enhanced phosphorylation of both S16 and T17, suggesting PKA and CaMKII activation in caveolae of CFs. RT-PCR analyses showed β2AR and β3AR were present in NRCFs. Stimulation with β2AR selective agonists activated both PKA and CaMKII, while β3AR elicited solely PKA activation, analyzed by using β3AR selective agonist/antagonist. In addition, in order to examine the significance of βAR stimulation for heart failure, we administered ISO continuously for two weeks in β2ARKO mice. As a result, fibrosis was suppressed in β2ARKO mice compared with wild-type mice (0.35% vs 2.37%, p<0.05) suggesting critical roles of β2AR in development of cardiac fibrosis caused by βAR stimulation in mice. Conclusions: Both β2 and β3AR are expressed in NRCFs and transduce distinct signaling and β2AR selective stimulation elicit development of cardiac fibrosis via activation of CaMKII signaling. Thus, selective βAR regulation could be potential novel anti-fibrotic therapeutics in HF.

Abstract 3503: Hydrogen Peroxide-Induced Afterdepolarizations are Dependent on Calmodulin Kinase II Signaling

Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Lai-Hua Xie ◽  
Fuhua Chen ◽  
James N Weiss
Keyword(s):  
Oxidative Stress ◽  
Hydrogen Peroxide ◽  
Ventricular Myocytes ◽  
Heart Association ◽  
Early Afterdepolarizations ◽  
Calmodulin Kinase ◽  
Repolarization Reserve ◽  
Delayed Afterdepolarizations ◽  
Rabbit Ventricular Myocytes ◽  
Camkii Activation

Background: In the heart, hydrogen peroxide (H 2 O 2 ) has been shown to cause early afterdepolarizations (EADs) and triggered activity by impairing Na current (I Na ) inactivation. Since H 2 O 2 has been recently shown to activate Ca 2+ /calmodulin kinase II (CaMKII), and since CaMKII activation has also been reported to impair I Na inactivation and predispose to EADs, we hypothesized that CaMKII activation by H 2 O 2 may be an important factor in the genesis of EADs induced by oxidative stress. Methods and Results: Patch-clamped Fluo-4 AM-loaded rabbit ventricular myocytes were exposed to H 2 O 2 (0.1–1mM), which induced spontaneous EADs after 5–15 min. Both the I Na blocker tetrodoxtin (TTX, 10 μM) and the I Ca,L blocker nifedipine shortened AP duration (APD) and suppressed EADs. H 2 O 2 increased both peak and steady-state I Ca,L under square-pulse voltage clamp, and enhanced I Ca,L to a greater extent during the AP plateau than during the AP upstroke under AP clamp conditions. In addition, by prolonging the AP plateau and increasing Ca influx via maintained I Ca,L , H 2 O 2 -induced EADs frequently caused DADs delayed afterdepolarizations (DADs) due to spontaneous SR Ca release waves after repolarization. KN-93(1 μM), a CaMKII inhibitor, prevented H 2 O 2 -induced EADs (n=4), whereas the inactive analogue KN-92 did not (n=5). Conclusion: These findings indicate that H 2 O 2 -induced EADs depend on both impaired I Na inactivation to reduce repolarization reserve and enhanced I Ca,L to reverse repolarization. Intact CaMKII signaling is necessary for EAD generation in this setting, presumably via its actions on I Na and I Ca,L , although direct redox effects on other ion channels/transporters may also be important. Our observations support a link between increased oxidative stress, CaMKII activation and afterdepolarizations as triggers of lethal ventricular arrhythmias in diseased heart. This research has received full or partial funding support from the American Heart Association, AHA National Center.

Abstract 17019: Two Distinct mechanisms by which Na+/Ca2+ dysregulation contributes to Arrhythmogenic Diastolic Ca2+ Release

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Przemyslaw Radwanski ◽  
Rengasayee Veeraraghavan ◽  
Björn Knollmann ◽  
Sándor Györke
Keyword(s):  
Ventricular Myocytes ◽  
Cellular Level ◽  
Polymorphic Ventricular Tachycardia ◽  
Cell Periphery ◽  
Individualized Approach ◽  
Triggered Arrhythmias ◽  
Local Contribution ◽  
Dependent Protein ◽  
Camkii Activation

Na + and Ca 2+ imbalance is associated with triggered arrhythmias resulting from diastolic Ca 2+ release (DCR) from sarcoplasmic reticulum (SR). Recent evidence suggests Na + channel blockade to be a promising therapy for pathologies, including catecholaminergic polymorphic ventricular tachycardia (CPVT). However, the specific mechanism(s) as to how Na + /Ca 2+ dysregulation contribute to arrhythmias is unknown. Confocal microscopy of ventricular myocytes isolated from CPVT mice lacking the cardiac calsequestrin was used to assess Ca 2+ handling response to isoproterenol (Iso) and various pharmacological interventions, while electrocardiograms were acquired during catecholamine challenge to assess the roles of various pools of Na + channels in CPVT. We identify two pools of Na + channels: one composed of cardiac-type Na + channels localized to cell periphery, and a ‘ local pool ’ comprised of neuronal Na + channels colocalizing with RyR2 in the T-tubules. Augmenting function of both Na + channel pools with ATX-II in the presence Iso resulted in SR Ca 2+ overload and activation of Ca 2+ /calmodulin-dependent protein kinase II (CaMKII), which precipitated DCR. These, in turn, translated into frequent arrhythmias in CPVT mice. Selectively augmenting function of ‘local pool’ neuronal Na + channels with β-Pompilidotoxin (β-PMTX) precipitated DCR on the cellular level causing frequent arrhythmias during catecholamine challenge in vivo . However, increasing local Na + fluxes reduced SR Ca 2+ load suggesting that local elevation in cytosolic Ca 2+ rather than global SR Ca 2+ overload underlies DCR and arrhythmias under such conditions. These data suggest two distinct mechanisms for Na + /Ca 2+ dysregulation-mediated arrhythmias. The first relies on SR Ca 2+ overload and CaMKII activation and the other on local contribution of Na + -Ca 2+ exchange to DCR. Consideration of these divergent mechanisms may enhance individualized approach to arrhythmia management.

ISCHEMIA-INDUCED CARDIAC ANGIOGENESIS IS MEDIATED BY CAMKII ACTIVATION

2019 ◽  
Vol 37 ◽  
pp. e219
Author(s):  
Y. Wang ◽  
Z. Chen ◽  
J. Cheng
Keyword(s):  
Camkii Activation

scholarly journals Role of Oxidation-Dependent CaMKII Activation in the Genesis of Abnormal Action Potentials in Atrial Cardiomyocytes: A Simulation Study

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Na Zhao ◽  
Qince Li ◽  
Haibo Sui ◽  
Henggui Zhang
Keyword(s):  
Oxidative Stress ◽  
Action Potential ◽  
Intracellular Calcium ◽  
Action Potentials ◽  
Cell Model ◽  
Atrial Arrhythmia ◽  
Electrical Excitation ◽  
Calcium Cycling ◽  
Simulation Results ◽  
Camkii Activation

Atrial fibrillation is a common cardiac arrhythmia with an increasing incidence rate. Particularly for the aging population, understanding the underlying mechanisms of atrial arrhythmia is important in designing clinical treatment. Recently, experiments have shown that atrial arrhythmia is associated with oxidative stress. In this study, an atrial cell model including oxidative-dependent Ca2+/calmodulin- (CaM-) dependent protein kinase II (CaMKII) activation was developed to explore the intrinsic mechanisms of atrial arrhythmia induced by oxidative stress. The simulation results showed that oxidative stress caused early afterdepolarizations (EADs) of action potentials by altering the dynamics of transmembrane currents and intracellular calcium cycling. Oxidative stress gradually elevated the concentration of calcium ions in the cytoplasm by enhancing the L-type Ca2+ current and sarcoplasmic reticulum (SR) calcium release. Owing to increased intracellular calcium concentration, the inward Na+/Ca2+ exchange current was elevated which slowed down the repolarization of the action potential. Thus, the action potential was prolonged and the L-type Ca2+ current was reactivated, resulting in the genesis of EAD. Furthermore, based on the atrial single-cell model, a two-dimensional (2D) ideal tissue model was developed to explore the effect of oxidative stress on the electrical excitation wave conduction in 2D tissue. Simulation results demonstrated that, under oxidative stress conditions, EAD hindered the conduction of electrical excitation and caused an unstable spiral wave, which could disrupt normal cardiac rhythm and cause atrial arrhythmia. This study showed the effects of excess reactive oxygen species on calcium cycling and action potential in atrial myocytes and provided insights regarding atrial arrhythmia induced by oxidative stress.

scholarly journals Diabetic Hyperglycemia Regulates Potassium Channels and Arrhythmias in the Heart via Autonomous CaMKII Activation by O-Linked Glycosylation

2019 ◽  
Vol 116 (3) ◽  
pp. 98a
Author(s):  
Bence Hegyi ◽  
Johanna M. Borst ◽  
Austen J. Lucena ◽  
Logan R.J. Bailey ◽  
Julie Bossuyt ◽  
...  
Keyword(s):  
Potassium Channels ◽  
Camkii Activation

scholarly journals CaMKII activation through NMDA2A receptor in the lateral amygdala is necessary for auditory fear conditined learning in mice

1999 ◽  
Vol 79 ◽  
pp. 55
Author(s):  
Yasuko Kouzu ◽  
Takahiro Moriya ◽  
Kaoni Yamashita-Suzuki ◽  
Kohji Fukunaga ◽  
Eiichi Miyamoto ◽  
...  
Keyword(s):  
Lateral Amygdala ◽  
Camkii Activation
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