Innervated human cardiac organoids as a disease model and drug therapy platform for L-type calcium channel - related arrhythmias

• Applicant: Maria Patapia Zafeiriou, Ph.D.
• Subject Area: Cardiology, Angiology ; Experimental Models for the Understanding of Nervous System Diseases ; Pediatric and Adolescent Medicine ; Pharmacology
• Term: since 2026
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 571770290

Timothy syndrome (TS), characterized by multi-organ system dysfunctions, is a rare disease caused by mutations in the calcium channel Cav1.2. TS is manifested in children with 60% mortality by 2.5 years of age. Cav1.2 dysfunction leads to developmental delays and seizures in the brain and ventricular arrhythmias in the heart. The latter are the most dangerous manifestations of TS with 70% of the TS children presenting life-threatening episodes. Although calcium channel and beta-adrenoreceptor blockers in combination with pacemakers and defibrillators are currently used to protect TS patients, they are often ineffective highlighting the need for novel therapeutic strategies. To develop novel therapies, the mechanism underlying the pathophysiology of TS needs to be elucidated not only at the cardiomyocyte but also at the autonomic neuron level. Autonomic neurons dictate cardiac beating rate, and their dysregulation during heart failure progression contributes to fatal ventricular arrhythmias. To our knowledge, the impact of Cav1.2 mutations on peripheral autonomic neuron function and their contribution to the observed arrhythmias remains unknown. To investigate human neurocardiac pathologies we plan to advance our previously established autonomically innervated engineered heart muscle (iEHM). iEHM is generated by fusion of an autonomic neuronal organoid and engineered heart muscle and represents a ventricular type of tissue. Due to the modular identity of iEHM, “mix&match” of isogenic and mutant iPSC-derived tissues can be used to delineate the cell type/organoid contribution to specific pathologies. In this study, we will implement a pacemaker node (PN) in iEHM that enhances tissue function and minimizes beating rate variability, providing an optimal model for investigating arrhythmias. Utilizing PN-iEHM, we aim to investigate the impact of Cav1.2 mutants p.G406R and p.G419R in autonomic neurons and cardiomyocyte function and the contribution of these populations to arrhythmia development. Next, we will evaluate the therapeutic potential of roscovitine to alleviate the phenotype. Finally, we will test antisense oligonucleotides (ASO) for their ability to reduce mutant RNA and rescue the pro-arrhythmic phenotype. This project will: (1) advance our knowledge about arrhythmia development in TS patients; (2) provide the first pre-clinical evidence for the therapeutic potential of ASO for the control of arrhythmias observed in TS children; (3) advance and establish a 3R-based model for future anti-arrhythmic drug screenings.

• DFG Programme: Research Grants