Distinct Myocardial Transcriptomic Profiles of Cardiomyopathies Stratified by the Mutant Genes

Abstract

Cardiovascular diseases are the number one cause of morbidity and mortality worldwide, but the underlying molecular mechanisms remain not well understood. Cardiomyopathies are primary diseases of the heart muscle and contribute to high rates of heart failure and sudden cardiac deaths. Here, we distinguished four different genetic cardiomyopathies based on gene expression signatures. In this study, RNA-Sequencing was used to identify gene expression signatures in myocardial tissue of cardiomyopathy patients in comparison to non-failing human hearts. Therefore, expression differences between patients with specific affected genes, namely LMNA (lamin A/C), RBM20 (RNA binding motif protein 20), TTN (titin) and PKP2 (plakophilin 2) were investigated. We identified genotype-specific differences in regulated pathways, Gene Ontology (GO) terms as well as gene groups like secreted or regulatory proteins and potential candidate drug targets revealing specific molecular pathomechanisms for the four subtypes of genetic cardiomyopathies. Some regulated pathways are common between patients with mutations in RBM20 and TTN as the splice factor RBM20 targets amongst other genes TTN, leading to a similar response on pathway level, even though many differentially expressed genes (DEGs) still differ between both sample types. The myocardium of patients with mutations in LMNA is widely associated with upregulated genes/pathways involved in immune response, whereas mutations in PKP2 lead to a downregulation of genes of the extracellular matrix. Our results contribute to further understanding of the underlying molecular pathomechanisms aiming for novel and better treatment of genetic cardiomyopathies.

Epigenetic modulators link mitochondrial redox homeostasis to cardiac function

“…Previously, we performed RNA sequencing on left ventricular tissue (LV) from end-stage patients with dilated cardiomyopathy harboring mutations in lamin A/C ( LMNA ), RNA binding motif protein 20 ( RBM20 ) and titin ( TTN ) (Sielemann et al, 2020). Here, to examine the involvement of mitochondria and related molecular pathways in heart failure, we performed Ingenuity Pathway Analysis (IPA) on these same data.…”

The Combined Human Genotype of Truncating TTN and RBM20 Mutations Is Associated with Severe and Early Onset of Dilated Cardiomyopathy

“…RNA-sequencing and read processing were performed as previously described [40]. Briefly, total RNA was isolated from about ~30 mg of myocardial tissue using the RNeasy Mini Kit (Qiagen, Hilden, Germany) and analyzed for RNA integrity number with the RNA 6000 Pico Kit (Agilent Technologies, Santa Clara, CA, USA).…”

“…For final indexed libraries enrichment seven PCR cycles were performed and the indexed libraries were quantified with Qubit dsDNA HS assay kit (ThermoFisher Scientific) and qualified with Bioanalyzer using HS DNA Kit (Agilent Technologies). Equimolar amounts of each library were pooled and sequenced on Illumina HiSeq 3000 (single-end; 50 bp) using sequencing-by-synthesis chemistry v4, according to the manufacturer's protocols and as previously described [40]. For each TruSeq RNA library, an average yield of 500 Mb of sequencing data with an average of 96% reads achieving a quality score ≥Q30 was produced.…”

Special Issue “Cardiovascular Genetics”

“…In most cases, the specific molecular and cellular changes of specific cardiomyopathy-associated mutations are unknown or can only be modelled in cell culture or in animal models because of the lack of explanted human myocardial tissue from mutation carriers. Of note, Sielemann et al used RNA-sequencing to perform detailed transcriptome analyses revealing differentially expressed genes and regulated pathways in explanted human myocardial tissue samples from cardiomyopathy patients with mutations in TTN (titin), LMNA (lamin A/C), RBM20 (RNA binding motif protein 20) and PKP2 (plakophilin-2) [ 17 ]. TTN , LMNA and RBM20 are the major DCM genes [ 18 , 19 , 20 ] and mutations in PKP2 are common in patients with ACM [ 21 ].…”

“…TTN , LMNA and RBM20 are the major DCM genes [ 18 , 19 , 20 ] and mutations in PKP2 are common in patients with ACM [ 21 ]. Interestingly, the gene expression signatures differ significantly in these four genetic cardiomyopathies indicating a complex and specific remodeling process in the diseased human hearts depending on the specific genotype [ 17 ]. However, the clinical cardiac phenotypes associated with mutations in specific genes can be broad.…”