Study of neuro-cardiomyocyte interactions in a novel innervated engineered heart muscle model from human induced pluripotent stem cells

• Applicant: Maria Patapia Zafeiriou, Ph.D.
• Subject Area: Cardiology, Angiology ; Experimental Models for the Understanding of Nervous System Diseases ; Molecular and Cellular Neurology and Neuropathology
• Term: since 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 496553893

Cardiovascular diseases represent, worldwide, the number one cause of death. Although cardiomyocytes and fibroblasts are the primary target cell types for studying mechanisms underlying cardiovascular disease, it is accepted that sympathetic neuron overdrive greatly contributes to heart failure. Moreover, there is a number of diseases known brain & heart (B&H) diseases, in which the heart is affected due to brain malfunction. Thus, there is a great need for models allowing to study neurocardiac interactions. Despite the value and wide application of animal models in disease modeling, the evolutionary gap between species leads to inevitable differences between humans and animals. Along with animal models human tissue engineering can increase the translational value of pre-clinical data. Thus, we developed a human neurocardiac interface in which a newly developed sympathetic neuronal organoid model (SNO) is fused with an established in vitro cardiac model termed engineered human myocardium (EHM). Both SNO and EHM are generated by directed differentiation of induced pluripotent stem cells in a three dimensional environment. To prove that neurons interact functionally with cardiomyocytes, we fused light stimulatable SNOs with non-optogenetic EHM tissues. Light stimulation of the SNO affected EHM chronotropy by evident increase of the tissue beating rate. These data provide proof-of principle that innervated-EHM (i-EHM) emulates a functional human neurocardiac interface.i-EHM model presents three major advantages: (1) it allows the study of electrically excitable networks of human sympathetic neurons and cardiomyocytes in a 3D environment; (2) it allows the measurement of inotropic and chronotropic effects of neuronal stimulation, via optogenetic tools, on the human myocardium; (3) since tissues are generated separately and are just allowed to fuse into one, “mix&match” of wild type and mutant iPSC-derived tissues can be used to delineate the cell type/organoid contribution to a specific pathologies.The current project aims: (1) to characterize in detail the innervated cardiac model (2) to provide evidence for the existence or not of neurocardiac synapse, which is until now under debate; (3) to investigate neuron- cardiomyocyte crosstalk mainly focusing on nerve growth factor, a neurotrophin secreted by cardiomyocytes with an important role in development and disease.Finally, although animal models are indispensable for research, we believe that complex human in vitro models, will provide novel opportunities for drug testing and personalized medicine. Thus, we hope that in the future, more targeted approaches, successfully tested in in vitro models as i-EHM, will be tested in animal models, reducing the number of animals subjected to experimentation.

• DFG Programme: Research Grants