2. Academic Validation
  3. MYBPC3-c.772G>A mutation results in haploinsufficiency and altered myosin cycling kinetics in a patient induced stem cell derived cardiomyocyte model of hypertrophic cardiomyopathy

MYBPC3-c.772G>A mutation results in haploinsufficiency and altered myosin cycling kinetics in a patient induced stem cell derived cardiomyocyte model of hypertrophic cardiomyopathy

  • J Mol Cell Cardiol. 2024 Apr 20:191:27-39. doi: 10.1016/j.yjmcc.2024.04.010.
Sonette Steczina 1,  Saffie Mohran 1,  Logan R J Bailey 2,  Timothy S McMillen 3,  Kristina B Kooiker 4,  Neil B Wood 5,  Jennifer Davis 6,  Michael J Previs 5,  Iacopo Olivotto 7,  Josè Manuel Pioner 8,  Michael A Geeves 9,  Corrado Poggesi 7,  Michael Regnier 10
Affiliations

Affiliations

  • 1 Department of Bioengineering, University of Washington, Seattle, WA 98109, USA; Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA 98109, USA.
  • 2 Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA 98109, USA; Molecular and Cellular Biology, University of Washington, Seattle, WA 98109, USA; Department of Lab Medicine and Pathology, University of Washington, Seattle, WA 98109, USA.
  • 3 Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA 98109, USA; Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, WA 98109, USA; Center for Translational Muscle Research, University of Washington, Seattle, WA 98109, USA.
  • 4 Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA 98109, USA; Division of Cardiology, Department of Medicine, University of Washington, Seattle, WA 98109, USA.
  • 5 Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, VT 05404, USA.
  • 6 Department of Bioengineering, University of Washington, Seattle, WA 98109, USA; Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA 98109, USA; Department of Lab Medicine and Pathology, University of Washington, Seattle, WA 98109, USA.
  • 7 Department of Experimental and Clinical Medicine, Division of Physiology, University of Florence, Italy.
  • 8 Department of Biology, University of Florence, Florence, Italy.
  • 9 Department of Biosciences, University of Kent, Canterbury, UK.
  • 10 Department of Bioengineering, University of Washington, Seattle, WA 98109, USA; Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA 98109, USA; Center for Translational Muscle Research, University of Washington, Seattle, WA 98109, USA. Electronic address: [email protected].
PMID: 38648963 DOI: 10.1016/j.yjmcc.2024.04.010
Abstract

Approximately 40% of hypertrophic cardiomyopathy (HCM) mutations are linked to the sarcomere protein cardiac Myosin binding protein-C (cMyBP-C). These mutations are either classified as missense mutations or truncation mutations. One mutation whose nature has been inconsistently reported in the literature is the MYBPC3-c.772G > A mutation. Using patient-derived human induced pluripotent stem cells differentiated to cardiomyocytes (hiPSC-CMs), we have performed a mechanistic study of the structure-function relationship for this MYBPC3-c.772G > A mutation versus a mutation corrected, isogenic cell line. Our results confirm that this mutation leads to exon skipping and mRNA truncation that ultimately suggests ∼20% less cMyBP-C protein (i.e., haploinsufficiency). This, in turn, results in increased Myosin recruitment and accelerated myofibril cycling kinetics. Our mechanistic studies suggest that faster ADP release from Myosin is a primary cause of accelerated myofibril cross-bridge cycling due to this mutation. Additionally, the reduction in force generating heads expected from faster ADP release during isometric contractions is outweighed by a cMyBP-C phosphorylation mediated increase in Myosin recruitment that leads to a net increase of myofibril force, primarily at submaximal calcium activations. These results match well with our previous report on contractile properties from myectomy samples of the patients from whom the hiPSC-CMs were generated, demonstrating that these cell lines are a good model to study this pathological mutation and extends our understanding of the mechanisms of altered contractile properties of this HCM MYBPC3-c.772G > A mutation.

Keywords

Cardiac myosin binding protein-C; Cross-bridge cycling; Haploinsufficiency; Hypertrophic cardiomyopathy; Truncation.

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