Cardiac myosin binding protein-C modulates actomyosin binding and kinetics in the in vitro motility assay

AbstractPhosphorylation of cardiac myosin-binding protein C (cMyBP-C), encoded by MYBPC3, increases the availability of myosin heads for interaction with actin thus enhancing contraction. cMyBP-C phosphorylation level is lower in septal myectomies of patients with hypertrophic cardiomyopathy (HCM) than in non-failing hearts. Here we compared the effect of phosphomimetic (D282) and wild-type (S282) cMyBP-C gene transfer on the HCM phenotype of engineered heart tissues (EHTs) generated from a mouse model carrying a Mybpc3 mutation (KI). KI EHTs showed lower levels of mutant Mybpc3 mRNA and protein, and altered gene expression compared with wild-type (WT) EHTs. Furthermore, KI EHTs exhibited faster spontaneous contractions and higher maximal force and sensitivity to external [Ca2+] under pacing. Adeno-associated virus-mediated gene transfer of D282 and S282 similarly restored Mybpc3 mRNA and protein levels and suppressed mutant Mybpc3 transcripts. Moreover, both exogenous cMyBP-C proteins were properly incorporated in the sarcomere. KI EHTs hypercontractility was similarly prevented by both treatments, but S282 had a stronger effect than D282 to normalize the force-Ca2+-relationship and the expression of dysregulated genes. These findings in an in vitro model indicate that S282 is a better choice than D282 to restore the HCM EHT phenotype. To which extent the results apply to human HCM remains to be seen.

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The C0-C1f Region of Cardiac Myosin Binding Protein-C Induces Pro-Inflammatory Responses in Fibroblasts via TLR4 Signaling

Cells ◽

10.3390/cells10061326 ◽

2021 ◽

Vol 10 (6) ◽

pp. 1326

Author(s):

Athiththan Yogeswaran ◽

Christian Troidl ◽

James W. McNamara ◽

Jochen Wilhelm ◽

Theresa Truschel ◽

...

Keyword(s):

Protein C ◽

Myocardial Injury ◽

Inflammatory Responses ◽

Binding Protein ◽

Cardiac Myosin ◽

Tlr4 Signaling ◽

Myosin Binding Protein ◽

Myosin Binding Protein C ◽

Myosin Binding

Myocardial injury is associated with inflammation and fibrosis. Cardiac myosin-binding protein-C (cMyBP-C) is cleaved by µ-calpain upon myocardial injury, releasing C0-C1f, an N-terminal peptide of cMyBP-C. Previously, we reported that the presence of C0-C1f is pathogenic within cardiac tissue and is able to activate macrophages. Fibroblasts also play a crucial role in cardiac remodeling arising from ischemic events, as they contribute to both inflammation and scar formation. To understand whether C0-C1f directly modulates fibroblast phenotype, we analyzed the impact of C0-C1f on a human fibroblast cell line in vitro by performing mRNA microarray screening, immunofluorescence staining, and quantitative real-time PCR. The underlying signaling pathways were investigated by KEGG analysis and determined more precisely by targeted inhibition of the potential signaling cascades in vitro. C0-C1f induced pro-inflammatory responses that might delay TGFβ-mediated myofibroblast conversion. TGFβ also counteracted C0-C1f-mediated fibroblast activation. Inhibition of TLR4 or NFkB as well as the delivery of miR-146 significantly reduced C0-C1f-mediated effects. In conclusion, C0-C1f induces inflammatory responses in human fibroblasts that are mediated via TRL4 signaling, which is decreased in the presence of TGFβ. Specific targeting of TLR4 signaling could be an innovative strategy to modulate C0-C1f-mediated inflammation.

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Pathogenic properties of the N-terminal region of cardiac myosin binding protein-C in vitro

Journal of Muscle Research and Cell Motility ◽

10.1007/s10974-012-9292-y ◽

2012 ◽

Vol 33 (1) ◽

pp. 17-30 ◽

Cited By ~ 24

Author(s):

Suresh Govindan ◽

Jason Sarkey ◽

Xiang Ji ◽

Nagalingam R. Sundaresan ◽

Mahesh P. Gupta ◽

...

Keyword(s):

Protein C ◽

Binding Protein ◽

Terminal Region ◽

Cardiac Myosin ◽

Myosin Binding Protein ◽

Myosin Binding Protein C ◽

Myosin Binding

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PKCε Increases Phosphorylation of the Cardiac Myosin Binding Protein C at Serine 302 both in Vitro and in Vivo†

Biochemistry ◽

10.1021/bi700467k ◽

2007 ◽

Vol 46 (23) ◽

pp. 7054-7061 ◽

Cited By ~ 31

Author(s):

Lei Xiao ◽

Qiong Zhao ◽

Yanmei Du ◽

Chao Yuan ◽

R. John Solaro ◽

...

Keyword(s):

Protein C ◽

Binding Protein ◽

Cardiac Myosin ◽

Myosin Binding Protein ◽

Myosin Binding Protein C ◽

Myosin Binding

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Biological variation of cardiac myosin-binding protein C in healthy individuals

Clinical Chemistry and Laboratory Medicine (CCLM) ◽

10.1515/cclm-2021-0306 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Bashir Alaour ◽

Torbjørn Omland ◽

Janniche Torsvik ◽

Thomas E. Kaier ◽

Marit S. Sylte ◽

...

Keyword(s):

Risk Stratification ◽

Protein C ◽

Myocardial Injury ◽

Binding Protein ◽

Biological Variation ◽

Cardiac Myosin ◽

Analytical Quality ◽

Myosin Binding Protein ◽

Myosin Binding Protein C ◽

Myosin Binding

Abstract Objectives Cardiac myosin-binding protein C (cMyC) is a novel biomarker of myocardial injury, with a promising role in the triage and risk stratification of patients presenting with acute cardiac disease. In this study, we assess the weekly biological variation of cMyC, to examine its potential in monitoring chronic myocardial injury, and to suggest analytical quality specification for routine use of the test in clinical practice. Methods Thirty healthy volunteers were included. Non-fasting samples were obtained once a week for ten consecutive weeks. Samples were tested in duplicate on the Erenna® platform by EMD Millipore Corporation. Outlying measurements and subjects were identified and excluded systematically, and homogeneity of analytical and within-subject variances was achieved before calculating the biological variability (CVI and CVG), reference change values (RCV) and index of individuality (II). Results Mean age was 38 (range, 21–64) years, and 16 participants were women (53%). The biological variation, RCV and II with 95% confidence interval (CI) were: CVA (%) 19.5 (17.8–21.6), CVI (%) 17.8 (14.8–21.0), CVG (%) 66.9 (50.4–109.9), RCV (%) 106.7 (96.6–120.1)/−51.6 (−54.6 to −49.1) and II 0.42 (0.29–0.56). There was a trend for women to have lower CVG. The calculated RCVs were comparable between genders. Conclusions cMyC exhibits acceptable RCV and low II suggesting that it could be suitable for disease monitoring, risk stratification and prognostication if measured serially. Analytical quality specifications based on biological variation are similar to those for cardiac troponin and should be achievable at clinically relevant concentrations.

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