Data on cardiac lncRNA STX18-AS1 expression in developing human hearts and function during in vitro hESC-cardiomyocyte differentiation

This article presents data concerning STX18-AS1, a long noncoding RNA gene identified from a Genome-wide association study of Atrial Septal Defect (ASD). The data describes its expression patterns in human tissues and functions in regulating cardiomyocyte differentiation in vitro. STX18-AS1 is a lncRNA with a higher abundance in developing tissues, including hearts. Its transcription distribution within the embryonic hearts during key heart septation stages supports STX18-AS1’s association with risk SNPs for ASD. The CRISPR stem cell pool in which STX18-AS1 was knocked down, showed reduced CM differentiation efficiency and lower expression of key cardiac transcriptional factors. This indicated its regulative role in supporting the lineage specification from cardiac mesoderm into cardiac progenitors and cardiomyocytes. These data can benefit the understanding of human embryonic heart developmental biology, and the time-course changes of cardiac transcriptional factors during in vitro cardiomyocyte differentiation from human embryonic stem cells

Association of Cholinergic Muscarinic M4 Receptor Gene Polymorphism with Schizophrenia

Background: Previous studies have linked muscarinic M4 receptors (CHRM4) to schizophrenia. Specifically, the rs2067482 polymorphism was found to be highly associated with this disease. Purpose: To test whether rs2067482 and rs72910092 are potential risk factors for schizophrenia and/or pharmacogenetic markers for antipsychotic-induced tardive dyskinesia. Patients and Methods: We genotyped DNA of 449 patients with schizophrenia and 134 healthy controls for rs2067482 and rs72910092 polymorphisms of the CHRM4 gene with the use of the MassARRAY® System by Agena Bioscience. Mann–Whitney test was used to compare qualitative traits and χ2 test was used for categorical traits. Results: The frequency of genotypes and alleles of rs72910092 did not differ between patients with schizophrenia and control subjects. We did not reveal any statistical differences for both rs2067482 and rs72910092 between schizophrenia patients with and without tardive dyskinesia. The frequency of the C allele of the polymorphic variant rs2067482 was significantly higher in healthy persons compared to patients with schizophrenia (OR=0.51, 95% CI [0.33–0.80]; p=0.003). Accordingly, the CC genotype was found significantly more often in healthy persons compared to patients with schizophrenia (OR=0.49, 95% CI [0.31–0.80]; p=0.010). Conclusion: Our study found the presence of the minor allele (T) of rs2067482 variant being associated with schizophrenia. We argue that the association of rs2067482 with schizophrenia may be via its regulatory effect on some other gene with protein kinase C and casein Kknase substrate in neurons 3 (PACSIN3) as a possible candidate. Neither rs2067482 nor rs72910092 is associated with tardive dyskinesia

Induced pluripotent stem cell modelling of HLHS underlines the contribution of dysfunctional NOTCH signalling to impaired cardiogenesis

Hypoplastic left heart syndrome (HLHS) is among the most severe forms of congenital heart disease. Although the consensus view is that reduced flow through the left heart during development is a key factor in the development of the condition, the molecular mechanisms leading to hypoplasia of left heart structures are unknown. We have generated induced pluripotent stem cells (iPSC) from five HLHS patients and two unaffected controls, differentiated these to cardiomyocytes and identified reproducible in vitro cellular and functional correlates of the HLHS phenotype. Our data indicate that HLHS-iPSC have a reduced ability to give rise to mesodermal, cardiac progenitors and mature cardiomyocytes and an enhanced ability to differentiate to smooth muscle cells. HLHS-iPSC-derived cardiomyocytes are characterised by a lower beating rate, disorganised sarcomeres and sarcoplasmic reticulum and a blunted response to isoprenaline. Whole exome sequencing of HLHS fibroblasts identified deleterious variants in NOTCH receptors and other genes involved in the NOTCH signalling pathway. Our data indicate that the expression of NOTCH receptors was significantly downregulated in HLHS-iPSC-derived cardiomyocytes alongside NOTCH target genes confirming downregulation of NOTCH signalling activity. Activation of NOTCH signalling via addition of Jagged peptide ligand during the differentiation of HLHS-iPSC restored their cardiomyocyte differentiation capacity and beating rate and suppressed the smooth muscle cell formation. Together, our data provide firm evidence for involvement of NOTCH signalling in HLHS pathogenesis, reveal novel genetic insights important for HLHS pathology and shed new insights into the role of this pathway during human cardiac developmen

Scientific Business Abstracts of the 113th Annual Meeting of the Association of Physicians of Great Britain and Ireland:Glypican-6 (GPC6) is a gene responsible for sporadic, non-syndromic Tetralogy of Fallot in humans

Dr Gennadiy Tenin started his scientific career as aresearcher in the University of Dundee (Scotland, UK) studyingthe termination of body axis elongation in chick embryo, followedby the short period in King’s College London investigatingmolecular control of head mesoderm patterning in chick. He thenmoved to the University of Manchester to work with Dr KathrynHentges, working on several projects, studying different aspectsof heart development using mouse as a model organism. As thenext step in his career, he started working with Prof BernardKeavney to identify new genes involved in cardiovascular development and congenital heart disease, using GWAS data inTetralogy of Fallot patients as the starting point. He currentlycontinues his research in the area, studying the function of theone of the newly identified genes during cardiogenesis.Congenital heart diseases (CHD) are the commonest birth defects and present in 9 out of 1000 live births. Tetralogy of Fallot (TOF) is the commonest cyanotic CHD; some 80% of TOF cases are sporadic and not due to a recognized genetic syndrome. Sporadic, non-syndromic TOF nonetheless exhibits significant heritability, and is considered to be a multigenic condition. Previously, a region of association on chr 13q31 (P ¼ 3.03 10–11) was discovered through genome-wide association studies (GWAS) in TOF patients but no causative gene identified. Integration of population genetics data, regional chromosomal interactions and embryonic expression data suggested that the nearby located gene Glypican-6 (GPC6) was the strongest candidate. GPC6 was found to be expressed exclusively in the endocardial cushions, transitory structures critical for cardiac septation. We used mouse gene knock-out to investigate the functional significance of Gpc6 in heart. Mice carrying a hypomorphic allele of Gpc6 displayed abnormalities in cushion development, leading to lower cell density in cardiac valves, thinner great vessels and, in some cases, a ventricular septal defect. The complete knock-out of Gpc6 resulted in double outlet right ventricle with mal-positioned aorta, a phenotype closely related to human TOF. The previously uncharacterized gene GPC6 was confirmed to be a novel causative gene for CHD, and is the first such gene to be identified from a GWAS approach. The glypicans, of which GPC6 is one, are heparan sulfate proteoglycans involved in a number of cell signalling pathways; this work newly identifies the role of the glypican gene family in heart development

Dynamic control of head mesoderm patterning

The embryonic head mesoderm gives rise to cranial muscle and contributes to the skull and heart. Prior to differentiation, the tissue is regionalised by the means of molecular markers. We show that this pattern is established in three discrete phases, all depending on extrinsic cues. Assaying for direct and first-wave indirect responses, we found that the process is controlled by dynamic combinatorial as well as antagonistic action of retinoic acid (RA), Bmp and Fgf signalling. In phase 1, the initial anteroposterior (a-p) subdivision of the head mesoderm is laid down in response to falling RA levels and activation of Fgf signalling. In phase 2, Bmp and Fgf signalling reinforce the a-p boundary and refine anterior marker gene expression. In phase 3, spreading Fgf signalling drives the a-p expansion of MyoR and Tbx1 expression along the pharynx, with RA limiting the expansion of MyoR. This establishes the mature head mesoderm pattern with markers distinguishing between the prospective extra-ocular and jaw skeletal muscles, the branchiomeric muscles and the cells for the outflow tract of the heart.</jats:p

Integration of Large-Scale Genomic Data Sources With Evolutionary History Reveals Novel Genetic Loci for Congenital Heart Disease

Background: Most cases of congenital heart disease (CHD) are sporadic and nonsyndromic, with poorly understood etiology. Rare genetic variants have been found to affect the risk of sporadic, nonsyndromic CHD, but individual studies to date are of only moderate sizes, and none to date has incorporated the ohnolog status of candidate genes in the analysis. Ohnologs are genes retained from ancestral whole-genome duplications during evolution; multiple lines of evidence suggest ohnologs are overrepresented among dosage-sensitive genes. We integrated large-scale data on rare variants with evolutionary information on ohnolog status to identify novel genetic loci predisposing to CHD. Methods: We compared copy number variants present in 4634 nonsyndromic CHD cases derived from publicly available data resources and the literature, and &gt;27 000 healthy individuals. We analyzed deletions and duplications independently and identified copy number variant regions exclusive to cases. These data were integrated with whole-exome sequencing data from 829 sporadic, nonsyndromic patients with Tetralogy of Fallot. We placed our findings in an evolutionary context by comparing the proportion of vertebrate ohnologs in CHD cases and controls. Results: Novel genetic loci in CHD cases were significantly enriched for ohnologs compared with the genome (χ2 test, P&lt;0.0001, OR =1.253 [95% CI, 1.199–1.309]). We identified 54 novel candidate protein-coding genes supported by both: (1) copy number variant and whole-exome sequencing data; and (2) ohnolog status. Conclusions: We have identified new CHD candidate loci, and show for the first time that ohnologs are overrepresented among CHD genes. Incorporation of evolutionary metrics may be useful in refining candidate genes emerging from large-scale genetic evaluations of CHD