Overexpression of human BAG3 P209L in mice causes restrictive cardiomyopathy

Nat Commun. 2021 Jun 11;12(1):3575. doi: 10.1038/s41467-021-23858-7.

Abstract

An amino acid exchange (P209L) in the HSPB8 binding site of the human co-chaperone BAG3 gives rise to severe childhood cardiomyopathy. To phenocopy the disease in mice and gain insight into its mechanisms, we generated humanized transgenic mouse models. Expression of human BAG3P209L-eGFP in mice caused Z-disc disintegration and formation of protein aggregates. This was accompanied by massive fibrosis resulting in early-onset restrictive cardiomyopathy with increased mortality as observed in patients. RNA-Seq and proteomics revealed changes in the protein quality control system and increased autophagy in hearts from hBAG3P209L-eGFP mice. The mutation renders hBAG3P209L less soluble in vivo and induces protein aggregation, but does not abrogate hBAG3 binding properties. In conclusion, we report a mouse model mimicking the human disease. Our data suggest that the disease mechanism is due to accumulation of hBAG3P209L and mouse Bag3, causing sequestering of components of the protein quality control system and autophagy machinery leading to sarcomere disruption.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Signal Transducing / genetics*
  • Adaptor Proteins, Signal Transducing / metabolism*
  • Animals
  • Apoptosis Regulatory Proteins / genetics*
  • Apoptosis Regulatory Proteins / metabolism*
  • Autophagy
  • Binding Sites
  • Cardiomyopathies / genetics
  • Cardiomyopathies / metabolism
  • Cardiomyopathies / therapy
  • Cardiomyopathy, Restrictive / genetics*
  • Cardiomyopathy, Restrictive / metabolism*
  • Cardiomyopathy, Restrictive / therapy
  • Child
  • Disease Models, Animal
  • Gene Expression Regulation
  • Genetic Therapy
  • Heart
  • Heat-Shock Proteins
  • Humans
  • Mice
  • Mice, Transgenic
  • Molecular Chaperones / metabolism
  • Mutation
  • Protein Binding
  • Proteomics
  • Sarcomeres / metabolism

Substances

  • Adaptor Proteins, Signal Transducing
  • Apoptosis Regulatory Proteins
  • BAG3 protein, human
  • Bag3 protein, mouse
  • HSPB8 protein, human
  • Heat-Shock Proteins
  • Molecular Chaperones