Identification of epigenetic mechanisms of transcriptional regulation in cardiac hypertrophy using Engineered Heart Tissue

• Applicant: Privatdozent Dr. Justus Stenzig
• Subject Area: Pharmacology
• Term: from 2017 to 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 386103693

Pathological cardiac hypertrophy leads to characteristic gene expression changes, believed to be partially causal and partially compensatory.The role of DNA methylation for the regulation of this process remains poorly understood and controversial. The proposed project will address this question in a humanized in vitro model.The proposed experiments will be based on our in vitro model of cardiac hypertrophy, in which artificial rat heart tissue (engineered heart tissue, EHT) is subjected to an increased afterload for 7 days. This intervention leads to cellular hypertrophy, impairment of contractile force, increased fibrosis and the induction of the hypertrophic gene programme, coinciding with a reciprocal DNA methylation pattern. In this model, treatment with an inhibitor of DNA methyl transferases (DNMTs) partially prevented the detrimental consequences of the hypertrophic intervention.In the proposed project the model of cardiac hypertrophy will be completely transitioned to human EHTs for which cardiomyocytes and fibroblasts will be differentiated from human induced pluripotent stem cells (hiPS cells). We are going to genetically modify hiPS cells using CRISPR-based gene editing to place DNMT1 and DNMT3A expression under the control of a tetracycline inducible promoter. Together, this will allow us to study the consequences of a selective loss of DNMT1 or DNMT3A - in either cardiomyocytes, fibroblasts or both - on contractile properties, histology, transcription and DNA methylation. Isolated knock-out of DNMTs in cardiac fibroblasts in vivo is virtually impossible at present, rendering this possibility in EHT unique.The proposed experiments will ideally provide further insight into the role of DNA methylation and different DNMT isoforms in heart disease and their possible therapeutic potential.

• DFG Programme: Research Grants
• Co-Investigator: Professor Dr. Thomas Eschenhagen