Multi-omics integration identifies key upstream regulators of pathomechanisms in hypertrophic cardiomyopathy due to truncating MYBPC3 mutations.

BACKGROUND: Hypertrophic cardiomyopathy (HCM) is the most common genetic disease of the cardiac muscle, frequently caused by mutations in MYBPC3. However, little is known about the upstream pathways and key regulators causing the disease. Therefore, we employed a multi-omics approach to study the pathomechanisms underlying HCM comparing patient hearts harboring MYBPC3 mutations to control hearts. RESULTS: Using H3K27ac ChIP-seq and RNA-seq we obtained 9310 differentially acetylated regions and 2033 differentially expressed genes, respectively, between 13 HCM and 10 control hearts. We obtained 441 differentially expressed proteins between 11 HCM and 8 control hearts using proteomics. By integrating multi-omics datasets, we identified a set of DNA regions and genes that differentiate HCM from control hearts and 53 protein-coding genes as the major contributors. This comprehensive analysis consistently points toward altered extracellular matrix formation, muscle contraction, and metabolism. Therefore, we studied enriched transcription factor (TF) binding motifs and identified 9 motif-encoded TFs, including KLF15, ETV4, AR, CLOCK, ETS2, GATA5, MEIS1, RXRA, and ZFX. Selected candidates were examined in stem cell-derived cardiomyocytes with and without mutated MYBPC3. Furthermore, we observed an abundance of acetylation signals and transcripts derived from cardiomyocytes compared to non-myocyte populations. CONCLUSIONS: By integrating histone acetylome, transcriptome, and proteome profiles, we identified major effector genes and protein networks that drive the pathological changes in HCM with mutated MYBPC3. Our work identifies 38 highly affected protein-coding genes as potential plasma HCM biomarkers and 9 TFs as potential upstream regulators of these pathomechanisms that may serve as possible therapeutic targets.

Strength of patient cohorts and biobanks for cardiomyopathy research.

In 2011 the Netherlands Heart Foundation allocated funding (CVON, Cardiovasculair Onderzoek Nederland) to stimulate collaboration between clinical and preclinical researchers on specific areas of research. One of those areas involves genetic heart diseases, which are frequently caused by pathogenic variants in genes that encode sarcomere proteins. In 2014, the DOSIS (Determinants of susceptibility in inherited cardiomyopathy: towards novel therapeutic approaches) consortium was initiated, focusing their research on secondary disease hits involved in the onset and progression of cardiomyopathies. Here we highlight several recent observations from our consortium and collaborators which may ultimately be relevant for clinical practice.

Bilateral hypoglossal nerve injury following the use of the laryngeal mask without the use of nitrous oxide.

Hypoglossal nerve injury is a rare complication of anaesthesia airway management in adults. Until now the use of nitrous oxide for anaesthesia supposedly contributed to this complication. We present a case of bilateral hypoglossal nerve injury following the use of a laryngeal mask airway without the use of nitrous oxide. At the conclusion of 3 h of surgery in extreme side rotation, a 15-year-old boy of 88 kg could not extend his tongue beyond his teeth. An MRI confirmed the absence of pharyngeal haematoma and the absence of thrombosis of the basilar artery. We conclude that even when patients have no medical history and nitrous oxide is not being used, prolongation of the operation in an extreme position might increase the risk of major complications with a laryngeal mask.

Chronic histopathological effects of parathion and 2,4-D on female gonads of Chasmagnathus granulata (Decapoda, Brachyura).

Female crabs of Chasmagnathus granulata, sampled at the external zone of the Rio de la Plata estuary, were chronically exposed to the pesticides parathion and 2,4-D, both of which have been extensively applied to crops in Argentina for a decade and have been detected several times above permissible levels in the estuary. After 2 months of female exposure to the pesticides during the reproductive season, the crabs' ovaries were dissected and fixed in Bouin's solution, to assess the possible effects of pesticides at the histological level. Parathion caused a significant increase in both previtellogenic and vitellogenic oocyte size, as well as a loss of the normal spherical shape of the oocytes. With 2,4-D, a significant decrease in vitellogenic oocyte size was noted, whereas the number of atretic follicles increased as a result of exposure to this herbicide. Several hypothetical mechanisms of action of these pesticides are discussed in relation to the effects observed. Although assayed concentrations were relatively high with respect to mean values detected in the mentioned estuary and its influents, persistent peaks may occur, especially in sediments. This work suggests a high potential risk from the pesticides studied to the reproductive performance of local aquatic fauna.

Variable temperature UHV dual-range cell for spectroscopic surface studies.

A stainless steel cell for transmission spectroscopy of surface compounds is described. This cell allows subsequent spectra recording of the sample in two spectral regions requiring different window materials. The sample temperature can be varied from 100 to 700 K, the pressure from 10(-6) to 10(5) Pa. The mean temperatue is measured inside the wafer with a thin platinum wire as a resistance thermometer.