A patient-specific engineered heart tissue model captured adult-like cardiomyopathy features better than monolayer cardiomyocytes.
Evidence
Preclinical iPSC and engineered heart tissue work compared a patient-derived BAG3 variant line with an isogenic pseudo-wild-type control across autophagy, mitochondrial, sarcomere, and contractility measures.
Caveat
The evidence comes from a patient-derived tissue model rather than clinical testing, and monolayer cells missed the age-associated sarcomere defect.
Simplified
Pathogenic mutations in Bcl2-associated athanogene 3 () cause genetic (DCM), a disease characterized by ventricular dilation, systolic dysfunction, and fibrosis. Previous studies have demonstrated that BAG3 mediates sarcomeric protein turnover through chaperone-assisted selective autophagy to maintain sarcomere integrity in the human heart. Although mouse models provide valuable insights into whole-organism effects of BAG3 knockout or pathogenic variants, their utility is limited by species-specific differences in pathophysiology, which often do not translate to humans and contribute to the failure of clinical trials. As a result, the development of induced pluripotent stem cell-derived cardiomyocytes (iCM) and engineered heart tissues presents a promising alternative for studying adult-onset cardiac diseases. Here, we used genome engineering to generate an isogenic pseudo-wild-type control cell line from a patient-derived iPSC line carrying a pathogenic BAG3 variant, clinically presenting with DCM. While monolayer iCMs recapitulated some features of BAG3-mediated DCM, such as reduced autophagy, mitochondrial membrane potential, and decreased HSPB8 stability, they failed to develop the age-associated impairment in sarcomere integrity. Therefore, we developed a mature, patient-specific, human engineered heart tissue model of BAG3-mediated DCM and compared it to its isogenic healthy control. We demonstrated successful recapitulation of adult-like features of the clinically observed disorganized sarcomeres and impaired tissue contractility, thereby providing a platform to investigate BAG3-related pathophysiology and therapeutic interventions.
Key numbers
2.6×
Improvement
Comparison of production between patient-derived and corrected tissues.
1
Score
Assessment of integrity in engineered heart tissues.
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