Phosphorylation of cardiac myosin binding protein-C (cMyBP-C) regulates sarcomeric structure, as well as myocardial contractility, and confers cardioprotection. My long-term goal is to define the role(s) of cMyBP-C phosphorylation in contractile function in order to understand the molecular mechanisms that underlie cardioprotection. We recently showed that (1) cMyBP-C is an easily releasable and soluble myofilament, (2) dephosphorylation of cMyBP-C results in its degradation and (3) release into the blood post-myocardial infarction (MI) and (4) its N'-fragments appear within 30 minutes of ischemia-reperfusion injury. In addition, we showed that plasma cMyBP-C levels are significantly increased in animal models and patients with MI. Strikingly, the level of plasma cMyBP-C is significantly higher than the gold standard plasma cardiac troponin I (2.0-fold molar). However, verification and validation of the precise amount of plasma cMyBP-C is the next critical step. Therefore, using selective and specific proteomic approaches, the short-term goal is to develop an assay that precisely quantitates the levels of plasma cMyBP-C. My central hypothesis is that cMyBP-C is a bone fide early, selective and measurable cardiac-specific biomarker, which appears within 30 minutes of ischemia. Thus, the overall objectives of the proposal are as follows: determine a cMyBP-C-specific amino acid region in order to develop a selective proteomics-based assay using the liquid chromatography-tandem-mass spectrometry (LC-MS-MS) and selective reaction monitoring (SRM) approaches (Specific Aim 1);verify the accuracy of the SRM approach for quantifying plasma cMyBP-C levels in both animal and human plasma samples (Specific Aim 2);and cross-validate the SRM assay with the conventional sandwich ELISA assay (Specific Aim 3). Plasma samples taken from ischemia- reperfusion-injured mice and patients with MI will be used in these analyses, compared to naive and sham operated mice and normal healthy controls. Validating the proteomic approaches will result in an assay that can accurately measure the level of cMyBP-C in the circulatory system, as well as define its presence as an early-released, cardiac-specific and selective marker of early-onset MI.
This proposal aims to confirm the efficacy of cardiac binding protein-C (cMyBP-C), a sarcomeric cardiac- specific thick filament assembly protein, as an early circulatory biomarker for myocardial infarction. Specifically, the proposed studies will verify and validate cMyBP-C plasma levels through advanced proteomic approaches, leading to the development of diagnostic assays that advance cardiac care.
| Viswanathan, Shiv Kumar; Puckelwartz, Megan J; Mehta, Ashish et al. (2018) Association of Cardiomyopathy With MYBPC3 D389V and MYBPC3?25bpIntronic Deletion in South Asian Descendants. JAMA Cardiol 3:481-488 |
| McNamara, James W; Grimes, Kelly M; Sadayappan, Sakthivel (2018) Basic Cardiovascular Sciences Scientific Sessions 2018. Circ Res 123:1024-1029 |
| McNamara, James W; Sadayappan, Sakthivel (2018) Skeletal myosin binding protein-C: An increasingly important regulator of striated muscle physiology. Arch Biochem Biophys 660:121-128 |
| Sadayappan, Sakthivel (2018) My Life, My Heart, and My(osin) Binding Protein-C. Circ Res 122:918-920 |
| Lin, Brian Leei; Song, Taejeong; Sadayappan, Sakthivel (2017) Myofilaments: Movers and Rulers of the Sarcomere. Compr Physiol 7:675-692 |
| Lynch 4th, Thomas L; Kuster, Diederik W D; Gonzalez, Beverly et al. (2017) Cardiac Myosin Binding Protein-C Autoantibodies are Potential Early Indicators of Cardiac Dysfunction and Patient Outcome in Acute Coronary Syndrome. JACC Basic Transl Sci 2:122-131 |
| Lynch 4th, Thomas L; Ismahil, Mohamed Ameen; Jegga, Anil G et al. (2017) Cardiac inflammation in genetic dilated cardiomyopathy caused by MYBPC3 mutation. J Mol Cell Cardiol 102:83-93 |
| Viswanathan, Shiv Kumar; Sanders, Heather K; McNamara, James W et al. (2017) Hypertrophic cardiomyopathy clinical phenotype is independent of gene mutation and mutation dosage. PLoS One 12:e0187948 |
| Sadayappan, Sakthivel (2017) The Myofilament Field Revisited in the Age of Cellular and Molecular Biology. Circ Res 121:601-603 |
| Sadayappan, Sakthivel (2017) Cardiovascular Early Careers: Past and Present. Circ Res 121:100-102 |
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