» Articles » PMID: 30586709

A Premature Termination Codon Mutation in MYBPC3 Causes Hypertrophic Cardiomyopathy Via Chronic Activation of Nonsense-Mediated Decay

Abstract

Background: Hypertrophic cardiomyopathy (HCM) is frequently caused by mutations in myosin-binding protein C3 ( MYBPC3) resulting in a premature termination codon (PTC). The underlying mechanisms of how PTC mutations in MYBPC3 lead to the onset and progression of HCM are poorly understood. This study's aim was to investigate the molecular mechanisms underlying the pathogenesis of HCM associated with MYBPC3 PTC mutations by utilizing human isogenic induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs).

Methods: Isogenic iPSC lines were generated from HCM patients harboring MYBPC3 PTC mutations (p.R943x; p.R1073P_Fsx4) using genome editing. Comprehensive phenotypic and transcriptome analyses were performed in the iPSC-CMs.

Results: We observed aberrant calcium handling properties with prolonged decay kinetics and elevated diastolic calcium levels in the absence of structural abnormalities or contracile dysfunction in HCM iPSC-CMs as compared to isogenic controls. The mRNA expression levels of MYBPC3 were significantly reduced in mutant iPSC-CMs, but the protein levels were comparable among isogenic iPSC-CMs, suggesting that haploinsufficiency of MYBPC3 does not contribute to the pathogenesis of HCM in vitro. Furthermore, truncated MYBPC3 peptides were not detected. At the molecular level, the nonsense-mediated decay pathway was activated, and a set of genes involved in major cardiac signaling pathways was dysregulated in HCM iPSC-CMs, indicating an HCM gene signature in vitro. Specific inhibition of the nonsense-mediated decay pathway in mutant iPSC-CMs resulted in reversal of the molecular phenotype and normalization of calcium-handling abnormalities.

Conclusions: iPSC-CMs carrying MYBPC3 PTC mutations displayed aberrant calcium signaling and molecular dysregulations in the absence of significant haploinsufficiency of MYBPC3 protein. Here we provided the first evidence of the direct connection between the chronically activated nonsense-mediated decay pathway and HCM disease development.

Citing Articles

AAV9-mediated MYBPC3 gene therapy with optimized expression cassette enhances cardiac function and survival in MYBPC3 cardiomyopathy models.

Greer-Short A, Greenwood A, Leon E, Qureshi T, von Kraut K, Wong J Nat Commun. 2025; 16(1):2196.

PMID: 40038304 PMC: 11880196. DOI: 10.1038/s41467-025-57481-7.


CRISPRi/a screens in human iPSC-cardiomyocytes identify glycolytic activation as a druggable target for doxorubicin-induced cardiotoxicity.

Liu C, Shen M, Liu Y, Manhas A, Zhao S, Zhang M Cell Stem Cell. 2024; 31(12):1760-1776.e9.

PMID: 39515331 PMC: 11646563. DOI: 10.1016/j.stem.2024.10.007.


Cardiomyopathy: pathogenesis and therapeutic interventions.

Huang S, Li J, Li Q, Wang Q, Zhou X, Chen J MedComm (2020). 2024; 5(11):e772.

PMID: 39465141 PMC: 11502724. DOI: 10.1002/mco2.772.


Patient-derived induced pluripotent stem cells to study non-canonical splicing variants associated with Hypertrophic Cardiomyopathy.

Jager J, Ribeiro M, Furtado M, Carvalho T, Syrris P, Lopes L Stem Cell Res. 2024; 81:103582.

PMID: 39447317 PMC: 11649531. DOI: 10.1016/j.scr.2024.103582.


CRISPR/Cas9 gene editing in induced pluripotent stem cells to investigate the feline hypertrophic cardiomyopathy causing MYBPC3/R820W mutation.

Dutton L, Dudhia J, Guest D, Connolly D PLoS One. 2024; 19(10):e0311761.

PMID: 39388496 PMC: 11466433. DOI: 10.1371/journal.pone.0311761.


References
1.
Sarikas A, Carrier L, Schenke C, Doll D, Flavigny J, Lindenberg K . Impairment of the ubiquitin-proteasome system by truncated cardiac myosin binding protein C mutants. Cardiovasc Res. 2005; 66(1):33-44. DOI: 10.1016/j.cardiores.2005.01.004. View

2.
Termglinchan V, Seeger T, Chen C, Wu J, Karakikes I . Efficient Genome Editing in Induced Pluripotent Stem Cells with Engineered Nucleases In Vitro. Methods Mol Biol. 2016; 1521:55-68. DOI: 10.1007/978-1-4939-6588-5_4. View

3.
Carrier L, Knoll R, Vignier N, Keller D, Bausero P, Prudhon B . Asymmetric septal hypertrophy in heterozygous cMyBP-C null mice. Cardiovasc Res. 2004; 63(2):293-304. DOI: 10.1016/j.cardiores.2004.04.009. View

4.
Karam R, Lou C, Kroeger H, Huang L, Lin J, Wilkinson M . The unfolded protein response is shaped by the NMD pathway. EMBO Rep. 2015; 16(5):599-609. PMC: 4428047. DOI: 10.15252/embr.201439696. View

5.
Birket M, Ribeiro M, Kosmidis G, Ward D, Leitoguinho A, van de Pol V . Contractile Defect Caused by Mutation in MYBPC3 Revealed under Conditions Optimized for Human PSC-Cardiomyocyte Function. Cell Rep. 2015; 13(4):733-745. PMC: 4644234. DOI: 10.1016/j.celrep.2015.09.025. View