Phosphomimetic cardiac myosin-binding protein C partially rescues a cardiomyopathy phenotype in murine engineered heart tissue

Alexander Dutsch, Paul J. M. Wijnker, Saskia Schlossarek, Felix W. Friedrich, Elisabeth Krämer, Ingke Braren, Marc N. Hirt, David Brenière-Letuffe, Alexandra Rhoden, Ingra Mannhardt, Thomas Eschenhagen, Lucie Carrier, Giulia Mearini

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Abstract

Phosphorylation 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.
Original languageEnglish
Article number18152
JournalScientific Reports
Volume9
Issue number1
DOIs
Publication statusPublished - 2019

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