TiGER · Titin can govern epigenetic remodelling

Heart disease is a staggering clinical and public health problem and the leading cause of death for both men and women in Western countries. The underlying pathomechanism of nearly all aetiologies relates to altered contractility and cardiac tissue tension but also gene expression changes and epigenomic remodelling. Within the sarcomere, the fundamental contractile unit in striated muscle, the giant protein titin is the major source of cardiac passive tension. Since sarcomeres are connected to the nucleus, I hypothesise that titin passive tension is transmitted to the nucleus and sensed by the mechano-sensitive nuclear lamina, affecting chromatin structure and gene expression, similar to cytoskeleton passive tension in nonmuscle cells. I will test this hypothesis in human cardiomyocytes derived from induced pluripotent stem cells (hiPSC-CMs) with either a low or high titin-derived passive tension by editing the titin gene locus. I will also investigate whether changes of titin tension affect sarcomere-resident chromatin remodellers: Smyd1, Smyd2, and HP1γ. Combining fluorescence and super-resolution imaging with chromatin-immunoprecipitation sequencing and RNA sequencing, I will delineate a comprehensive map of titin-derived epigenetic remodelling in hiPSC-CMs. The TiGER project will dissect a complex biophysical mechanism leveraging on hiPSC-CMs as they represent an exceptional platform to unveil human cardiac-specific phenomena that require extensive gene editing, culture, and imaging. As titin-derived passive tension changes during development, physiology, and disease, TiGER’s results could have major implications for cardiac pathophysiology and could unlock future compelling research avenues. I will explore this novel role for titin as an epigenetic remodeller under the supervision of Prof. Dr. Gotthardt, a world-leading expert of cardiac mechanotransduction and titin at the Max Delbrück Center (MDC) in Berlin.