Laminin-alpha4 and integrin-linked kinase mutations cause human cardiomyopathy via simultaneous defects in cardiomyocytes and endothelial cells

Knöll, R., Postel, R., Wang, J., Krätzner, R., Hennecke, G., Vacaru, A.M., Vakeel, P., Schubert, C., Murthy, K., Rana, B.K., Kube, D., Knöll, G., Schäfer, K., Hayashi, T., Holm, T., Kimura, A., Schork, N., Toliat, M.R., Nürnberg, P., Schultheiss, H.P., Schaper, W., Schaper, J., Bos, E., den Hertog, J., van Eeden, F.J., Peters, P.J., Hasenfuss, G., Chien, K.R., and Bakkers, J.
Circulation   116(5): 515-525 (Journal)
Registered Authors
Bakkers, Jeroen, den Hertog, Jeroen, Postel, Ruben, van Eeden, Freek
MeSH Terms
  • Adult
  • Amino Acid Substitution
  • Animals
  • COS Cells
  • Cardiomyopathy, Dilated/genetics*
  • Cardiomyopathy, Dilated/metabolism
  • Cardiomyopathy, Dilated/pathology
  • Cell Adhesion
  • Chlorocebus aethiops
  • Chromosome Mapping
  • Codon, Nonsense
  • DNA Mutational Analysis
  • Embryo, Nonmammalian/pathology
  • Endothelial Cells/pathology*
  • Epigenesis, Genetic
  • Extracellular Matrix/metabolism
  • Extracellular Matrix/pathology
  • Female
  • Heart/embryology
  • Heart Failure/etiology
  • Heart Failure/pathology
  • Humans
  • Integrins/metabolism
  • Laminin/genetics*
  • Laminin/physiology
  • Male
  • Middle Aged
  • Models, Molecular
  • Mutation, Missense*
  • Myocardium/pathology
  • Myocytes, Cardiac/pathology*
  • Oligonucleotides, Antisense/toxicity
  • Pedigree
  • Point Mutation*
  • Protein Binding
  • Protein Conformation
  • Protein Interaction Mapping
  • Protein Serine-Threonine Kinases/genetics*
  • Protein Serine-Threonine Kinases/physiology
  • Protein Structure, Tertiary
  • Transfection
  • Zebrafish/embryology
  • Zebrafish/genetics
  • Zebrafish Proteins/genetics
  • Zebrafish Proteins/physiology
17646580 Full text @ Circulation
BACKGROUND: Extracellular matrix proteins, such as laminins, and endothelial cells are known to influence cardiomyocyte performance; however, the underlying molecular mechanisms remain poorly understood. METHODS AND RESULTS: We used a forward genetic screen in zebrafish to identify novel genes required for myocardial function and were able to identify the lost-contact (loc) mutant, which encodes a nonsense mutation in the integrin-linked kinase (ilk) gene. This loc/ilk mutant is associated with a severe defect in cardiomyocytes and endothelial cells that leads to severe myocardial dysfunction. Additional experiments revealed the epistatic regulation between laminin-alpha4 (Lama4), integrin, and Ilk, which led us to screen for mutations in the human ILK and LAMA4 genes in patients with severe dilated cardiomyopathy. We identified 2 novel amino acid residue-altering mutations (2828C>T [Pro943Leu] and 3217C>T [Arg1073X]) in the integrin-interacting domain of the LAMA4 gene and 1 mutation (785C>T [Ala262Val]) in the ILK gene. Biacore quantitative protein/protein interaction data, which have been used to determine the equilibrium dissociation constants, point to the loss of integrin-binding capacity in case of the Pro943Leu (Kd=5+/-3 micromol/L) and Arg1073X LAMA4 (Kd=1+/-0.2 micromol/L) mutants compared with the wild-type LAMA4 protein (Kd=440+/-20 nmol/L). Additional functional data point to the loss of endothelial cells in affected patients as a direct consequence of the mutant genes, which ultimately leads to heart failure. CONCLUSIONS: This is the first report on mutations in the laminin, integrin, and ILK system in human cardiomyopathy, which has consequences for endothelial cells as well as for cardiomyocytes, thus providing a new genetic basis for dilated cardiomyopathy in humans.
Genes / Markers
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Mutations / Transgenics
Human Disease / Model
Sequence Targeting Reagents
Engineered Foreign Genes