SCALE

About the SCALE-project

Hypertrophic cardiomyopathy (HCM) is mainly caused by heterozygous mutations in sarcomeric genes. Patients express both, the wild-type and the mutated allele. A SCALE consortium member showed that the fraction of mutated mRNA differs between neighboring cardiomyocytes (CM) in cardiac tissue.

This cell-to-cell allelic imbalance is associated with a contractile imbalance between the CMs – mosaicism in the myocardium that may contribute to the HCM phenotype. To address the cause and consequence of cell-to-cell allelic imbalance, we will mainly focus on single CMs originating from HCM patients with different mutations.

First, we will study the hypothesis that the percentage of the mutant alleles is associated with altered gene expression (Aim 1). For this purpose, (single-cell) full-length RNA sequencing using short and long reads will be performed on individual CMs from 2D- and 3D-cultures of induced pluripotent stem cells. We will correlate the percentage of reads supporting the mutated allele per cell to its transcriptional profile.

Next, we address the underlying mechanisms of allelic imbalance (Aim 2). We will perform chromatin immunoprecipitation sequencing on CMs to evaluate the chromatin regulation effect on allelic expression, and analyze the potential effects of alternative splicing.

Lastly, we aim to modulate the cell-to-cell allelic imbalance to minimize functional mosaicism (Aim 3). To achieve this we will interfere with cultured CMs using compounds that might revert the allelic imbalance as possible treatment options.