Mouse and computational models link Mlc2v dephosphorylation to altered myosin kinetics in early cardiac disease

Sheikh, Farah; Ouyang, Kunfu; Campbell, Stuart G.; Lyon, Robert C.; Chuang, Joyce; Fitzsimons, Dan; Tangney, Jared R.; Hidalgo, Carlos; Chung, Charles S.; Cheng, Hongqiang; Dalton, Nancy D.; Gu, Yusu; Kasahara, Hideko; Ghassemian, Majid; Omens, Jeffrey H.; Peterson, Kirk L.; Granzier, Henk; Moss, Richard L.; McCulloch, Andrew D.; Chen, Ju

doi:10.1172/jci61134

Cited by 138 publications

(208 citation statements)

References 53 publications

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“…We used a computational model of myocyte shortening (26,27) to explore the mechanisms that would explain the paradox of the cardiomyocyte calcium transient and cell shortening data. We first constructed idealized calcium transients (Fig.…”

Section: Resultsmentioning

confidence: 99%

Decreased polycystin 2 expression alters calcium-contraction coupling and changes β-adrenergic signaling pathways

Kuo¹,

Kwaczala

Nguyen³

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

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Cardiac disorders are the main cause of mortality in autosomaldominant polycystic kidney disease (ADPKD). However, how mutated polycystins predispose patients with ADPKD to cardiac pathologies before development of renal dysfunction is unknown. We investigate the effect of decreased levels of polycystin 2 (PC2), a calcium channel that interacts with the ryanodine receptor, on myocardial function. We hypothesize that heterozygous PC2 mice (Pkd2 +/− ) undergo cardiac remodeling as a result of changes in calcium handling, separate from renal complications. We found that Pkd2 +/− cardiomyocytes have altered calcium handling, independent of desensitized calcium-contraction coupling. Paradoxically, in Pkd2 +/− mice, protein kinase A (PKA) phosphorylation of phospholamban (PLB) was decreased, whereas PKA phosphorylation of troponin I was increased, explaining the decoupling between calcium signaling and contractility. In silico modeling supported this relationship. Echocardiography measurements showed that Pkd2 +/− mice have increased left ventricular ejection fraction after stimulation with isoproterenol (ISO), a β-adrenergic receptor (βAR) agonist. Blockers of βAR-1 and βAR-2 inhibited the ISO response in Pkd2 +/− mice, suggesting that the dephosphorylated state of PLB is primarily by βAR-2 signaling. Importantly, the Pkd2 +/− mice were normotensive and had no evidence of renal cysts. Our results showed that decreased PC2 levels shifted the βAR pathway balance and changed expression of calcium handling proteins, which resulted in altered cardiac contractility. We propose that PC2 levels in the heart may directly contribute to cardiac remodeling in patients with ADPKD in the absence of renal dysfunction.calcium signaling | β-adrenergic receptor blocker | excitation contraction coupling

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Section: Resultsmentioning

confidence: 99%

Decreased polycystin 2 expression alters calcium-contraction coupling and changes β-adrenergic signaling pathways

Kuo¹,

Kwaczala

Nguyen³

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

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“…31 The downregulation of cardiac MLCK decreases the steady-state levels of MLC2 phosphorylated; therefore, it was proposed to be the main myosin kinase acting on cardiac myocytes. 31,32 Decreased levels of phosphorylated MLC2-P have been observed in HF. 33 In addition, these studies demonstrated a global decrease of myofilament protein phosphorylation occurring during HF.…”

Section: Discussionmentioning

confidence: 99%

RNA-sequencing analysis reveals new alterations in cardiomyocyte cytoskeletal genes in patients with heart failure

Herrer

Roselló‐Lletí

Rivera

et al. 2014

Laboratory Investigation

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Changes in cardiomyocyte cytoskeletal components, a crucial scaffold of cellular structure, have been found in heart failure (HF); however, the altered cytoskeletal network remains to be elucidated. This study investigated a new map of cytoskeleton-linked alterations that further explain the cardiomyocyte morphology and contraction disruption in HF. RNA-Sequencing (RNA-Seq) analysis was performed in 29 human LV tissue samples from ischemic cardiomyopathy (ICM; n ¼ 13) and dilated cardiomyopathy (DCM, n ¼ 10) patients undergoing cardiac transplantation and six healthy donors (control, CNT) and up to 16 ICM, 13 DCM and 7 CNT tissue samples for qRT-PCR. Gene Ontology analysis of RNA-Seq data demonstrated that cytoskeletal processes are altered in HF. We identified 60 differentially expressed cytoskeleton-related genes in ICM and 58 genes in DCM comparing with CNT, hierarchical clustering determined that shared cytoskeletal genes have a similar behavior in both pathologies. We further investigated MYLK4, RHOU, and ANKRD1 cytoskeletal components. qRT-PCR analysis revealed that MYLK4 was downregulated ( À 2.2-fold; Po0.05) and ANKRD1 was upregulated (2.3-fold; Po0.01) in ICM patients vs CNT. RHOU mRNA levels showed a statistical trend to decrease ( À 2.9-fold). In DCM vs CNT, MYLK4 ( À 4.0-fold; Po0.05) and RHOU ( À 3.9-fold; Po0.05) were downregulated and ANKRD1 (2.5-fold; Po0.05) was upregulated. Accordingly, MYLK4 and ANKRD1 protein levels were decreased and increased, respectively, in both diseases. Furthermore, ANKRD1 and RHOU mRNA levels were related with LV function (Po0.05). In summary, we have found a new map of changes in the ICM and DCM cardiomyocyte cytoskeleton. ANKRD1 and RHOU mRNA levels were related with LV function which emphasizes their relevance in HF. These new cytoskeletal changes may be responsible for altered contraction and cell architecture disruption in HF patients. Moreover, these results improve our knowledge on the role of cytoskeleton in functional and structural alterations in HF.

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“…Phosphorylation of Ser15 has been recognized to play an important role in cardiac muscle contraction under normal and disease conditions (9). Significantly reduced RLC phosphorylation was reported in patients with heart failure (10, 11) and observed in animal models of cardiac disease (5, [12][13][14]. Attenuation of RLC phosphorylation in cardiac MLCK knockout mice led to ventricular myocyte hypertrophy, with histological evidence of necrosis and fibrosis, and to mild dilated cardiomyopathy (15,16).…”

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confidence: 99%

Constitutive phosphorylation of cardiac myosin regulatory light chain prevents development of hypertrophic cardiomyopathy in mice

Yuan

Muthu

Kazmierczak

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

127

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Myosin light chain kinase (MLCK)-dependent phosphorylation of the regulatory light chain (RLC) of cardiac myosin is known to play a beneficial role in heart disease, but the idea of a phosphorylation-mediated reversal of a hypertrophic cardiomyopathy (HCM) phenotype is novel. Our previous studies on transgenic (Tg) HCM-RLC mice revealed that the D166V (Aspartate166 →Valine) mutation-induced changes in heart morphology and function coincided with largely reduced RLC phosphorylation in situ. We hypothesized that the introduction of a constitutively phosphorylated Serine15 (S15D) into the hearts of D166V mice would prevent the development of a deleterious HCM phenotype. In support of this notion, MLCK-induced phosphorylation of D166V-mutated hearts was found to rescue some of their abnormal contractile properties. Tg-S15D-D166V mice were generated with the human cardiac RLC-S15D-D166V construct substituted for mouse cardiac RLC and were subjected to functional, structural, and morphological assessments. The results were compared with Tg-WT and Tg-D166V mice expressing the human ventricular RLC-WT or its D166V mutant, respectively. Echocardiography and invasive hemodynamic studies demonstrated significant improvements of intact heart function in S15D-D166V mice compared with D166V, with the systolic and diastolic indices reaching those monitored in WT mice. A largely reduced maximal tension and abnormally high myofilament Ca 2+ sensitivity observed in D166V-mutated hearts were reversed in S15D-D166V mice. Lowangle X-ray diffraction study revealed that altered myofilament structures present in HCM-D166V mice were mitigated in S15D-D166V rescue mice. Our collective results suggest that expression of pseudophosphorylated RLC in the hearts of HCM mice is sufficient to prevent the development of the pathological HCM phenotype.cardiomyopathy | hemodynamics | myocardial contraction | X-ray structure | myosin RLC

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Mouse and computational models link Mlc2v dephosphorylation to altered myosin kinetics in early cardiac disease

Cited by 138 publications

References 53 publications

Decreased polycystin 2 expression alters calcium-contraction coupling and changes β-adrenergic signaling pathways

Decreased polycystin 2 expression alters calcium-contraction coupling and changes β-adrenergic signaling pathways

RNA-sequencing analysis reveals new alterations in cardiomyocyte cytoskeletal genes in patients with heart failure

Constitutive phosphorylation of cardiac myosin regulatory light chain prevents development of hypertrophic cardiomyopathy in mice

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