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Stem cell research is the product of cumulative, integrated effort between and within laboratories and disciplines. The many collaborative steps that lead to that special "Eureka moment", when something that has been a puzzle perhaps for years suddenly become clear, is among the greatest pleasures of a scientific career. In this essay, the serendipitous pathway from first acquaintance with pluripotent stem cells to advanced cardiovascular models that emerged from studying development and disease will be described. Perhaps inspiration for later generations of stem cell researchers simply to follow whatever they find interesting. [ABSTRACT FROM AUTHOR]

Smyd1, a member of the Smyd lysine methyltransferase family, plays an important role in myofibrillogenesis of skeletal and cardiac muscles. Loss of Smyd1b (a Smyd1 ortholog) function in zebrafish results in embryonic death from heart malfunction. smyd1b encodes two isoforms, Smyd1b_tv1 and Smyd1b_tv2, differing by 13 amino acids due to alternative splicing. While smyd1 alternative splicing is evolutionarily conserved, the isoform-specific expression and function of Smyd1b_tv1 and Smyd1b_tv2 remained unknown. Here we analyzed their expression and function in skeletal and cardiac muscles. Our analysis revealed expression of smyd1b_tv1 predominately in cardiac and smyd1b_tv2 in skeletal muscles. Using zebrafish models expressing only one isoform, we demonstrated that Smyd1b_tv1 is essential for cardiomyocyte differentiation and fish viability, whereas Smyd1b_tv2 is dispensable for heart development and fish survival. Cellular and biochemical analyses revealed that Smyd1b_tv1 differs from Smyd1b_tv2 in protein localization and binding with myosin chaperones. While Smyd1b_tv2 diffused in the cytosol of muscle cells, Smyd1b_tv1 was localized to M-lines and essential for sarcomere organization in cardiomyocytes. Co-IP analysis revealed a stronger binding of Smyd1b_tv1 with chaperones and cochaperones compared with Smyd1b_tv2. Collectively, these findings highlight the nonequivalence of Smyd1b isoforms in cardiomyocyte differentiation, emphasizing the critical role of Smyd1b_tv1 in cardiac function. [ABSTRACT FROM AUTHOR]

Heart development is a complex spatiotemporal process involving a series of orchestrated morphogenic events that result in the formation of an efficient pumping organ. How posttranslational mechanisms regulate heart development remains poorly understood. Therefore, we investigate how neddylation, the attachment of NEDD8 to target proteins, coordinates cardiogenesis. Abrogation of neddylation by deleting Nae1 in the heart via Sm22α Cre led to early embryonic lethality. Mutant hearts exhibited deficits in trabeculation and expansion of the compact layer due to reduced cardiomyocyte proliferation, which was linked to abnormal Notch signaling in the developing heart. Overall, our findings demonstrate an essential role for neddylation in cardiogenesis. [Display omitted] • Neddylation is an emerging post-translational protein modification. • Deletion of Nae1 (NEDD8-activating enzyme E1 subunit 1) via Sm22α Cre is sufficient to abolish neddylation in the heart. • Inhibition of neddylation results in myocardial hypoplasia and embryonic lethality. • Neddylation is required for cardiomyocyte proliferation and the fine-tuning of Notch signaling. • Neddylation is a crucial post-translational mechanism that regulates cardiogenesis. [ABSTRACT FROM AUTHOR]

DNA methylation and microRNA (miRNA) expression are epigenetic mechanisms essential for regulating tissue-specific gene expression and metabolic processes. However, high-resolution transcriptome, methylome, or miRNAome data is only available for a few model organisms and selected tissues. Up to date, only a few studies have reported on gene expression, DNA methylation, or miRNA expression in adult equine tissues at the genome-wide level. In the present study, we used RNA-Seq, miRNA-seq, and reduced representation bisulfite sequencing (RRBS) data from the heart, lung, and liver tissues of healthy cold-blooded horses to identify differentially expressed genes (DEGs), differentially expressed miRNA (DE miRNA) and differentially methylated sites (DMSs) between three types of horse tissues. Additionally, based on integrative omics analysis, we described the observed interactions of epigenetic mechanisms with tissue-specific gene expression alterations. The obtained data allowed identification from 4067 to 6143 DMSs, 9733 to 11,263 mRNAs, and 155 to 185 microRNAs, differentially expressed between various tissues. We pointed out specific genes whose expression level displayed a negative correlation with the level of CpG methylation and miRNA expression and revealed biological processes that they enrich. Furthermore, we confirmed and validated the accuracy of the Next-Generation Sequencing (NGS) results with bisulfite sequencing PCR (BSP) and quantitative PCR (qPCR). This comprehensive analysis forms a strong foundation for exploring the epigenetic mechanisms involved in tissue differentiation, especially the growth and development of the equine heart, lungs, and liver. [ABSTRACT FROM AUTHOR]

The contamination of food and feed by mycotoxins, particularly zearalenone (ZEA) and deoxynivalenol (DON), is a global issue. Prenatal exposure to ZEA and DON can result in congenital cardiac malformations in fetuses. Addressing the prevention and mitigation of embryonic cardiotoxicity caused by these toxins is crucial. Citrus limonoid nomilin (NOM) is an extract known for its pathological properties in various diseases. This study investigated the potential mechanism of NOM in mitigating cardiotoxicity caused by ZEA and DON co-exposure in a zebrafish model. The findings indicated that NOM pretreatment alleviated cardiac developmental toxicity induced by ZEA and DON and normalized the expression of key genes involved in heart development, including gata4, vmhc, nkx2.5, and sox9b. Co-exposure to NOM, ZEA, and DON enhanced SOD and catalase activity, increased glutathione levels, and reduced ROS and malondialdehyde production. Furthermore, NOM reduced cardiac oxidative damage by activating the Keap1/Nrf2 signaling pathway. In summary, this study offers new insights for preventive interventions against congenital heart disease caused by mycotoxin exposure. [ABSTRACT FROM AUTHOR]

Cardiac fibroblasts, have lower gene transfer efficiency compared to dermal fibroblasts, posing challenges for plasmid-based gene transfer methods. A higher transfer efficiency could enable improved insight into heart pathology and development of novel therapeutic targets. In this study we compared eleven commercially available transfection reagents and eight plasmid purification methods. Finally, we systematically evaluated 150 unique transfection conditions (incubation times, addition of innate immune inhibitors, reagent to plasmid ratios etc) to optimize the methodology. The aim was to develop an optimized plasmid transfection protocol specifically tailored for primary human cardiac fibroblasts with high efficiency and minimal toxicity. While the actual transfection efficiency, indicated by the expression of fluorescent proteins, was less than 5%, our optimized protocol was sufficient for achieving significant gene expression levels needed for experimental applications such as luciferase enhancer-promoter assays. Leveraging our newly developed methodology, we could perform comprehensive profiling of nine viral and native enhancer/promoters, revealing regulatory sequences governing classical fibroblast marker (VIM) and resident cardiac fibroblast marker (TCF21) expression. We believe that these findings can help advance many aspects of cardiovascular research. In conclusion, we here report for the first time a plasmid transfection protocol for cardiac fibroblasts with minimal cell toxicity and sufficient efficiency for functional genomic studies. [ABSTRACT FROM AUTHOR]

Cardiac differentiation of human pluripotent stem cells is not only a new strategy of regenerative therapy for cardiovascular disease treatment but also provides unique opportunities for the study of in vitro disease models and human heart development. To elucidate the dynamic gene regulatory networks and pivotal regulators involved in the cardiomyocyte differentiation process, we conducted an analysis of single-cell RNA sequencing data obtained from the reprogramming of two human induced pluripotent stem cell (iPSC) lines into cardiomyocytes. The data were collected from 32,365 cells at 4 stages of this process. We successfully identified cardiomyocyte clusters and several other cell clusters with different molecular characteristics derived from iPSC and described the differentiation trajectory of cardiomyocytes during differentiation in vitro. Through differential gene analysis and SCENIC analysis, we identified several candidate genes including CREG and NR2F2 that play an important regulatory role in cardiomyocyte lineage commitment. This study provides the key differentiation trajectory of heart differentiation in vitro at single-cell resolution and reveals the molecular basis of heart development and differentiation of iPSC-derived cardiomyocytes. [ABSTRACT FROM AUTHOR]

Congenital heart disease (CHD) has an incidence of approximately 1%. Over the last decade, sequencing studies including large cohorts of individuals with CHD have begun to unravel the genetic mechanisms underpinning CHD. This includes the identification of variants in cyclin‐dependent kinase 13 (CDK13), in individuals with syndromic CHD. CDK13 encodes a serine/threonine protein kinase. The cyclin partner of CDK13 is cyclin K; this complex is thought to be important in transcription and RNA processing. Pathogenic variants in CDK13 cause CDK13‐related disorder in humans, characterised by intellectual disability and developmental delay, recognisable facial features, feeding difficulties and structural brain defects, with 35% of individuals having CHD. To obtain a greater understanding for the role that this essential protein kinase plays in embryonic heart development, we have analysed a presumed loss of function Cdk13 transgenic mouse model (Cdk13tm1b). The homozygous mutants were embryonically lethal in most cases by E15.5. X‐gal staining showed Cdk13 expression localised to developing facial regions, heart and surrounding areas at E10.5, whereas at E12.5, it was more widely present. In the E15.5 heart, staining was seen throughout. RT‐qPCR showed significant reduction in Cdk13 transcript expression in homozygous compared with WT and heterozygous hearts at E10.5 and E12.5. Detailed morphological 3D analysis of embryonic and postnatal hearts was performed using high‐resolution episcopic microscopy, which affords a more detailed analysis of structures such as cardiac valve leaflets and endocardial cushions, compared with more traditional histological techniques. We show that both the homozygous and heterozygous Cdk13tm1b mutants exhibit a range of CHD, including ventricular septal defects, bicuspid aortic valve, double outlet right ventricle and atrioventricular septal defects. 100% (n = 4) of homozygous hearts displayed CHD. Differential expression was seen in Cdk13tm1b homozygous mutants for two genes known to be necessary for normal heart development. The types of defects, and the presence of CHD in heterozygous mice (17.02%, n = 8/47), are consistent with the CDK13‐related disorder phenotype in humans. This study provides important insights into the effects of reduced function of CDK13 in the mouse heart and contributes to our understanding of the mechanism behind this disorder as a cause of CHD. [ABSTRACT FROM AUTHOR]

Notch signaling activation drives an endothelial-to-mesenchymal transition (EndMT) critical for heart development, although evidence suggests that the reprogramming of endothelial cell metabolism can regulate endothelial function independent of canonical cell signaling. Herein, we investigated the crosstalk between Notch signaling and metabolic reprogramming in the EndMT process. Biochemically, we find that the NOTCH1 intracellular domain (NICD1) localizes to endothelial cell mitochondria, where it interacts with and activates the complex to enhance mitochondrial metabolism. Targeting NICD1 to mitochondria induces more EndMT compared with wild-type NICD1, and small molecule activation of PDH during pregnancy improves the phenotype in a mouse model of congenital heart defect. A NOTCH1 mutation observed in non-syndromic tetralogy of Fallot patients decreases NICD1 mitochondrial localization and subsequent PDH activity in heart tissues. Altogether, our findings demonstrate NICD1 enrichment in mitochondria of the developing mouse heart, which induces EndMT by activating PDH and subsequently improving mitochondrial metabolism. Notch signaling activation drives an endothelial-to-mesenchymal transition critical for heart development. Here, the authors investigate the role of NOTCH1 intracellular domain (NICD1) in the mitochondria of developing mouse fetal hearts. [ABSTRACT FROM AUTHOR]

22q11.2 deletion syndrome (22q11.2DS) is the most common chromosomal microdeletion syndrome. Congenital heart defects are prevalent in 22q11.2DS but the etiology is still poorly understood. In this study, we aimed to gain mechanistic insights into the heart defects that result from 22q11.2 deletion, with a focus on Slc25a1, which is located in the deletion segment. Whereas global knockout of Slc25a1 in mice produced a variety of heart malformations, cardiac deletion of Slc25a1 had little effect on heart development. We then found that trophoblast-specific Slc25a1 deletion recapitulated heart anomalies in the global knockout mice. Further study identified SLC25A1 as a regulator of trophoblast and placental development through modulation of histone H3K27 acetylation at the promoters and enhancers of key genes involved in trophoblast differentiation. Finally, administration of recombinant human pregnancy-specific glycoprotein 1 (PSG1), a trophoblast-derived secretory glycoprotein, partially corrected placental and embryonic heart defects. This study defines the role of SLC25A1 in heart development by regulating placental development, and provides new insights to understand the etiology of 22q11.2DS. [ABSTRACT FROM AUTHOR]

Cardiac cellular fate transition holds remarkable promise for the treatment of ischemic heart disease. We report that overexpressing two transcription factors, Sall4 and Gata4, which play distinct and overlapping roles in both pluripotent stem cell reprogramming and embryonic heart development, induces a fraction of stem-like cells in rodent cardiac fibroblasts that exhibit unlimited ex vivo expandability with clonogenicity. Transcriptomic and phenotypic analyses reveal that around 32 ± 6.4% of the expanding cells express Nkx2.5, while 13 ± 3.6% express Oct4. Activated signaling pathways like PI3K/Akt, Hippo, Wnt, and multiple epigenetic modification enzymes are also detected. Under suitable conditions, these cells demonstrate a high susceptibility to differentiating into cardiomyocyte, endothelial cell, and extracardiac neuron-like cells. The presence of partially pluripotent-like cells is characterized by alkaline phosphatase staining, germ layer marker expression, and tumor formation in injected mice (n = 5). Additionally, significant stem-like fate transitions and cardiogenic abilities are induced in human cardiac fibroblasts, but not in rat or human skin fibroblasts. Molecularly, we identify that SALL4 and GATA4 physically interact and synergistically stimulate the promoters of pluripotency genes but repress fibrogenic gene, which correlates with a primitive transition process. Together, this study uncovers a new cardiac regenerative mechanism that could potentially advance therapeutic endeavors and tissue engineering. [ABSTRACT FROM AUTHOR]

Introduction: Maternal obesity has been positively correlated with an increased cardiometabolic risk in the offspring throughout life, implying intergenerational transmission. However, little is known about the early-life cardiac cell modifications that imply the onset of heart diseases later in life. This study analyzed cardiac progenitor cells and cardiomyocyte differentiation on day of birth in the offspring born to obese dams. Methods: The litter size reduction model was used to induce obesity in female Swiss mice. Both maternal groups, the Small Litter Dams (SLD-F1), which were overfed during lactation, and the Normal Litter Dams (NLD-F1), control group, were mated to healthy male mice. Their first-generation offspring (SLD-F2 and NLD-F2, n = 6 by group) were euthanized on birth. Results: Mothers from SLD had increased body mass, Lee Index, fat deposits, hyperglycemia, and glucose intolerance, confirming the obese phenotype. The offspring born from SLD-F1 had also increased body mass, Lee Index, and fasting hyperglycemia. The heart of SLD-F2 showed decreased cardiac mass/body mass ratio, increased cardiac collagen deposits, a greater number of undifferentiated cardiac c-kit+ and Sca-1+ progenitor cells, and increased NKX2.5+ cardiomyoblasts compared to control. In addition, SLD-F2 demonstrated immature cardiomyocytes. Conclusions: Obese dams negatively impact their offspring, leading to altered biometric and metabolic parameters, along with an immature heart already at birth, with extracellular matrix adverse remodeling, delayed cardiac progenitor cell differentiation, and restrained cardiomyocyte maturation, which can be related to the development of cardiometabolic disease in the adulthood. [ABSTRACT FROM AUTHOR]

Nr2f transcription factors (TFs) are conserved regulators of vertebrate atrial cardiomyocyte (AC) differentiation. However, little is known about the mechanisms directing Nr2f expression in ACs. Here, we identified a conserved enhancer 3' to the nr2f1a locus, which we call 3'reg1-nr2f1a (3'reg1), that can promote Nr2f1a expression in ACs. Sequence analysis of the enhancer identified putative Lef/Tcf and Foxf TF binding sites. Mutation of the Lef/Tcf sites within the 3'reg1 reporter, knockdown of Tcf7l1a, and manipulation of canonical Wnt signaling support that Tcf7l1a is derepressed via Wnt signaling to activate the transgenic enhancer and promote AC differentiation. Similarly, mutation of the Foxf binding sites in the 3'reg1 reporter, coupled with gain- and loss-of-function analysis supported that Foxf1 promotes expression of the enhancer and AC differentiation. Functionally, we find that Wnt signaling acts downstream of Foxf1 to promote expression of the 3'reg1 reporter within ACs and, importantly, both Foxf1 and Wnt signaling require Nr2f1a to promote a surplus of differentiated ACs. CRISPR-mediated deletion of the endogenous 3'reg1 abrogates the ability of Foxf1 and Wnt signaling to produce surplus ACs in zebrafish embryos. Together, our data support that downstream members of a conserved regulatory network involving Wnt signaling and Foxf1 function on a nr2f1a enhancer to promote AC differentiation in the zebrafish heart. Author summary: Vertebrate hearts are comprised of atrial chambers, which receive blood, and ventricular chambers which expel blood, whose functions need to be coordinated for proper blood circulation. During development, different genetic programs direct the development of these chambers within the vertebrate heart. Members of a family of genes called Nr2fs are conserved regulators of atrial chamber development in vertebrates, with mutations in Nr2f2 of humans being associated with congenital heart defects affecting the atrium. Here, we examine how the gene nr2f1a, which is required for normal atrial chamber development in the model zebrafish, is regulated. Using tools, including transgenic reporter lines and genetic mutants, we identify that factors previously shown to regulate atrial chamber development in mammals have conserved roles regulating a genetic element that promotes nr2f1a expression within developing atrial cells. Since there is a lack of understanding regarding regulation of Nr2f genes during vertebrate atrial cell development, our work provides insights into the conservation of genetic networks that promote heart development in vertebrates and if perturbed could underlie congenital heart defects. [ABSTRACT FROM AUTHOR]

Simple Summary: During the embryonic development of vertebrates, the heart is the first organ to develop through cardiogenesis, a specialized and complex process that include several morphogenetic pathways. Any disruption that influences the onset expression of key role genes could impact the correct development of the heart and, consequently, the presence of congenital heart diseases (CHDs). These CHDs are defined as structural and conduction abnormalities and are considered to have multifactorial etiology. Within these malformations, the septal defects such as ventricular (VSD) and atrial septal defects (ASD), are the most common forms of CHDs. Studies have reported that CHDs are the result of genetic and environmental factors. Here, we review and summarize the role of genetics involved in cardiogenesis and congenital cardiac septal defects. Congenital heart diseases (CHDs) are a group of complex diseases characterized by structural and functional malformations during development in the human heart; they represent an important problem for public health worldwide. Within these malformations, septal defects such as ventricular (VSD) and atrial septal defects (ASD) are the most common forms of CHDs. Studies have reported that CHDs are the result of genetic and environmental factors. Here, we review and summarize the role of genetics involved in cardiogenesis and congenital cardiac septal defects. Moreover, treatment regarding these congenital cardiac septal defects is also addressed. [ABSTRACT FROM AUTHOR]

Background: Mesenchymal stem cells (MSCs) are safe and effective in treating myocardial infarction (MI) and have broad application prospects. However, the heterogeneity of MSCs may affect their therapeutic effect on the disease. We recently found that MSCs derived from different segments of the same umbilical cord (UC) showed significant difference in the expression of genes that are related to heart development and injury repair. We therefore hypothesized that those MSCs with high expression of above genes are more effective to treat MI and tested it in this study. Methods: MSCs were isolated from 3 cm-long segments of the maternal, middle and fetal segments of the UC (maternal-MSCs, middle-MSCs and fetal-MSCs, respectively). RNA-seq was used to analyze and compare the transcriptomes. We verified the effects of MSCs on oxygen-glucose deprivation (OGD)-induced cardiomyocyte apoptosis in vitro. In vivo, a rat MI model was established by ligating the left anterior descending coronary artery, and MSCs were injected into the myocardium surrounding the MI site. The therapeutic effects of MSCs derived from different segments of the UC were evaluated by examining cardiac function, histopathology, cardiomyocyte apoptosis, and angiogenesis. Results: Compared to fetal-MSCs and middle-MSCs, maternal-MSCs exhibited significantly higher expression of genes that are associated with heart development, such as GATA-binding protein 4 (GATA4), and myocardin (MYOCD). Coculture with maternal-MSCs reduced OGD-induced cardiomyocyte apoptosis. In rats with MI, maternal-MSCs significantly restored cardiac contractile function and reduced the infarct size. Mechanistic experiments revealed that maternal-MSCs exerted cardioprotective effects by decreasing cardiomyocyte apoptosis, and promoting angiogenesis. Conclusion: Our data demonstrated that maternal segment-derived MSCs were a superior cell source for regenerative repair after MI. Segmental localization of the entire UC when isolating hUCMSCs was necessary to improve the effectiveness of clinical applications. [ABSTRACT FROM AUTHOR]

At a local level, the role of urban green spaces for tackling sustainability issues has received renewed attention, in line with a wider shift in thinking which places cities at the heart of sustainable development action. In parallel, funding for green space provision has reduced, prompting Local Authorities to reimagine how green spaces are governed, including transferring authority to communities. Preference for community-led green spaces is frequently justified with reference to normative arguments derived from “commons” theory, which advocate for self-governing institutions as effective means of managing local resources. What is lacking in this literature is a contemporary focus on urban settings, operational prescription, and an awareness of the real challenges facing self-governance. To fill this gap, the different interactions with, and claims over, a self-governed nature reserve in Bristol, UK, are investigated; alongside the operational and legal mechanisms deployed in its governance and management. Findings reveal that governing commonly held green space in an urban context is highly complex and requires reconciling a multiplicity of claims, interests, and values. This manifests in tensions and challenges for governance, including trade-offs between autonomy and wider support, problematic decisions around prioritisation; and difficulty in establishing and legitimising norms whilst advocating for shared use. This deep empirical case provides valuable insights for policymakers and theorists as they continue to make decisions concerning the future of urban green spaces, in different localities and across scales. [ABSTRACT FROM AUTHOR]

The initial contraction of the heart during the embryonic stage necessitates a substantial energy supply, predominantly derived from mitochondrial function. However, during embryonic heart development, mitochondria influence beyond energy supplementation. Increasing evidence suggests that mitochondrial permeability transition pore opening and closing, mitochondrial fusion and fission, mitophagy, reactive oxygen species production, apoptosis regulation, Ca2+ homeostasis, and cellular redox state also play critical roles in early cardiac development. Therefore, this review aims to describe the essential roles of mitochondrial non-energetic function embryonic cardiac development. [ABSTRACT FROM AUTHOR]

Simple Summary: Scientists have developed new techniques that allow them to study the heart at an incredibly detailed level, focusing on individual cells rather than looking at groups of cells together. This is important because the heart is made up of many different types of cells, each with its own role, and understanding how they interact is key to discovering what happens in both healthy hearts and in heart disease. By using methods that look at the genes, proteins, and other molecules inside single cells, researchers can uncover how cells communicate and change over time. These discoveries are helping scientists learn more about how the heart develops, how it stays healthy, and what goes wrong in heart diseases. This knowledge could lead to better treatments and new ways to diagnose heart conditions, helping people live longer, healthier lives. By directly measuring multiple molecular features in hundreds to millions of single cells, single-cell techniques allow for comprehensive characterization of the diversity of cells in the heart. These single-cell transcriptome and multi-omic studies are transforming our understanding of heart development and disease. Compared with single-dimensional inspections, the combination of transcriptomes with spatial dimensions and other omics can provide a comprehensive understanding of single-cell functions, microenvironment, dynamic processes, and their interrelationships. In this review, we will introduce the latest advances in cardiac health and disease at single-cell resolution; single-cell detection methods that can be used for transcriptome, genome, epigenome, and proteome analysis; single-cell multi-omics; as well as their future application prospects. [ABSTRACT FROM AUTHOR]

Congenital heart defects are leading causes of neonatal mortality and are often associated with placental abnormalities, but mechanisms linking placenta and heart development are poorly understood. Herein, we investigated a potential signaling network connecting the placenta and nascent heart in mice. We found that fetal hearts exposed to media conditioned by placental tissue or differentiated wild-type trophoblast stem (TS) cells, but not undifferentiated TS cells, showed increased heart rate and epicardial cell outgrowth. This effect was not observed when hearts were exposed to media from TS cells lacking OVO-Like 2, a transcription factor required for trophoblast differentiation and placental development. Trophoblasts released abundant extracellular vesicles into media, and these vesicles were sufficient to mediate cardio-promoting effects. Our findings provide a potential mechanism whereby the placenta communicates with the fetal heart to promote cardiac morphogenesis, and offers insight into the link between poor placentation and a higher incidence of heart defects. Poor development of the placenta is linked with heart problems. This study reveals that extracellular vesicles from placental trophoblasts promote heart development in mice, shedding light on how placental health affects cardiac formation. [ABSTRACT FROM AUTHOR]

Thermal performance curves (TPCs) provide a framework for understanding the effects of temperature on ectotherm performance and fitness. TPCs are often used to test hypotheses regarding local adaptation to temperature or to develop predictions for how organisms will respond to climate warming. However, for aquatic organisms such as fishes, most TPCs have been estimated for adult life stages, and little is known about the shape of TPCs or the potential for thermal adaptation at sensitive embryonic life stages. To examine how latitudinal gradients shape TPCs at early life stages in fishes, we used two populations of Fundulus heteroclitus that have been shown to exhibit latitudinal variation along the thermal cline as adults. We exposed embryos from both northern and southern populations and their reciprocal crosses to eight different temperatures (15°C, 18°C, 21°C, 24°C, 27°C, 30°C, 33°C, and 36°C) until hatch and examined the effects of developmental temperature on embryonic and larval traits (shape of TPCs, heart rate, and body size). We found that the pure southern embryos had a right‐shifted TPC (higher thermal optimum (Topt) for developmental rate, survival, and embryonic growth rate) whereas pure northern embryos had a vertically shifted TPC (higher maximum performance (Pmax) for developmental rate). Differences across larval traits and cross‐type were also found, such that northern crosses hatched faster and hatched at a smaller size compared to the pure southern population. Overall, these observed differences in embryonic and larval traits are consistent with patterns of both local adaptation and countergradient variation. Highlights: Local adaptation and countergradient variation influence the shape of embryo thermal performance curves in two locally adapted populations of killifish. Embryos also had a narrower thermal breadth than adults due to reduced cold tolerance. [ABSTRACT FROM AUTHOR]

The second heart field (SHF) plays a pivotal role in heart development, particularly in outflow tract (OFT) morphogenesis and septation, as well as in the expansion of the right ventricle (RV). Two mouse Cre lines, the Mef2c - AHF - Cre (Mef2c - Cre) and Isl1 - Cre , have been widely used to study the SHF development. However, Cre activity is triggered not only in the SHF but also in the RV in the Mef2c - Cre mice, and in the Isl1 - Cre mice, Cre activation is not SHF-specific. Therefore, a more suitable SHF-Cre line is desirable for better understanding SHF development. Here, we generated and characterized the Prdm1 -Cre knock-in mice. In comparison with Mef2c - Cre mice, the Cre activity is similar in the pharyngeal and splanchnic mesoderm, and in the OFT of the Prdm1 - Cre mice. Nonetheless, it was noticed that Cre expression is largely reduced in the RV of Prdm1 - Cre mice compared to the Mef2c - Cre mice. Furthermore, we deleted Hand2 , Nkx2-5 , Pdk1 and Tbx20 using both Mef2c - Cre and Prdm1 - Cre mice to study OFT morphogenesis and septation, making a comparison between these two Cre lines. New insights were obtained in understanding SHF development including differentiation into cardiomyocytes in the OFT using Prdm1 - Cre mice. In conclusion, we found that Prdm1 - Cre mouse line is a more appropriate tool to monitor SHF development, while the Mef2c-Cre mice are excellent in studying the role and function of the SHF in OFT morphogenesis and septation. [Display omitted] • Lineage tracing using Prdm1 - Cre mice reveals Cre expression in the second heart field progenitors and derivatives. • Comparison of Prdm1 - Cre and Mef2c - Cre mediated gene deletion distinguishes difference in second heart field development. • Prdm1 - Cre is suitable for studying second heart development. • Mef2c - Cre is an excellent tool to investigate cardiac outflow tract morphogenesis and septation. [ABSTRACT FROM AUTHOR]

The heart is the central organ of the circulatory system, and its proper development is vital to maintain human life. As fetal heart development is complex and poorly understood, we use single-cell RNA sequencing to profile the gene expression landscapes of human fetal hearts from the four-time points: 8, 10, 11, 17 gestational weeks (GW8, GW10, GW11, GW17), and identified 11 major types of cells: erythroid cells, fibroblasts, heart endothelial cells, ventricular cardiomyocytes, atrial cardiomyocytes, macrophage, DCs, smooth muscle, pericytes, neural cells, schwann cells. In addition, we identified a series of differentially expressed genes and signaling pathways in each cell type between different gestational weeks. Notably, we found that ANNEXIN, MIF, PTN, GRN signalling pathways were simple and fewer intercellular connections in GW8, however, they were significantly more complex and had more intercellular communication in GW10, GW11, and GW17. Notably, the interaction strength of OSM signalling pathways was gradually decreased during this period of time (from GW8 to GW17). Together, in this study, we presented a comprehensive and clear description of the differentiation processes of all the main cell types in the human fetal hearts, which may provide information and reference data for heart regeneration and heart disease treatment. [Display omitted] • Gene expression map of human fetal hearts from the four-time points were identified. • Dynamic alteration of cell subpopulations and gene expression during heart development. • ANNEXIN, MIF, PTN, GRN, OSM signalling pathways are crucial in heart development. [ABSTRACT FROM AUTHOR]

Embryology is an essential component to understanding human anatomy. It requires an in‐depth understanding of 3D knowledge but is primarily taught with 2‐dimensional resources. In particular, the development of the human heart is a complex process and difficult to understand using traditional teaching methods. We present here a series of heart embryology models created to supplement embryology education and aid students in understanding this complex process. Using Polydoh moldable plastic, models representing six different critical steps in heart formation are described, including: the fusing of the heart tubes (days 21–23), beginning of the cardiac loop (early day 23), fully formed cardiac loop (late day 23), four‐week heart, formation of the endocardial cushions and septi (late fourth week), and heart with fully formed septi with functioning foramen ovale (sixth week). These models not only improve embryology education but also the understanding of heart pathologies. This method provides an affordable option for embryology education and provides students with learning tools that assist with the comprehension of the development of a complex organ. [ABSTRACT FROM AUTHOR]

Transcriptional enhancers direct precise gene expression patterns during development and harbor the majority of variants associated with phenotypic diversity, evolutionary adaptations, and disease. Pinpointing which enhancer variants contribute to changes in gene expression and phenotypes is a major challenge. Here, we find that suboptimal or low-affinity binding sites are necessary for precise gene expression during heart development. Single-nucleotide variants (SNVs) can optimize the affinity of ETS binding sites, causing gain-of-function (GOF) gene expression, cell migration defects, and phenotypes as severe as extra beating hearts in the marine chordate Ciona robusta. In human induced pluripotent stem cell (iPSC)-derived cardiomyocytes, a SNV within a human GATA4 enhancer increases ETS binding affinity and causes GOF enhancer activity. The prevalence of suboptimal-affinity sites within enhancers creates a vulnerability whereby affinity-optimizing SNVs can lead to GOF gene expression, changes in cellular identity, and organismal-level phenotypes that could contribute to the evolution of novel traits or diseases.

In experiments on 3-day-old rats to identify the possible involvement of adrenoreceptors (AR) in the development of pathologic heart rhythm with high-amplitude (> 0.5 s) bradycardic complexes (PHRBC) occurring in newborn rats after NiCl2 administration, a comparative analysis of changes in heart rate variability (HRV), heart rate, and respiration after injection of nickel chloride and a high dose of the β-AR agonist isoproterenol was carried out. Injection of NiCl2, which blocks T-type voltage-dependent Ca2+ channels (T-VDCC), causes in 100% of rats the occurrence of PHRBC accompanied by a decrease in the role of neural influences and an increase in the role of neurohumoral factors in the mechanisms of heart rate regulation. Activation of β-AR causes shifts of physiological parameters qualitatively and quantitatively similar to those observed after NiCl2 poisoning in rats, but PHRBC does not occur. Pharmacological analysis with premedication of rats with β-AR antagonists (propranolol, atenolol) or α-AR antagonists (phentolamine) followed by NiCl2 administration showed that β-AR blockade with the nonselective adrenolytic propranolol prevents the development of PSRBC in half of the rats. In animals with pathologic arrhythmia occurring after NiCl2 injection, a rapid increase in the load on the sympathoadrenal system is noted, and the initial (background) instability of the mechanisms of heart rhythm regulation is revealed. Blockade of α- and β1-AR does not prevent the development of PHRBC during subsequent NiCl2 administration, which suggests the participation of β2-AR in the development of arrhythmia. Administration of the selective β2-AR agonist clenbuterol to rats leads to a decrease in HRV, including neurohumoral regulation and the appearance of low-amplitude (< 0.1 s) bradycardic complexes (BC) in 22% of rats. The results obtained by us together with the analysis of the literature suggest that β-AR plays an important role in the complex changes in the balance of regulatory influences in the occurrence of PHRBCs. Activation of β1-AR contributes to increased release of catecholamines by adrenal chromaffin cells, increased role of neurohumoral component of heart rhythm regulation and causes activation of β2-AR. Blockade of β2-AR, on the contrary, reduces the release of catecholamines and prevents the development of pathological arrhythmia. The second necessary factor leading to the development of arrhythmias with high-amplitude BCs is blockade of T-type calcium channels. [ABSTRACT FROM AUTHOR]

Background: Newborn resuscitation algorithms have since the turn of the century been more evidence-based. In this review, we discuss the development of American Heart Association (AHA) and the International Liaison Committee on Resuscitation (ILCOR)'s algorithm for newborn resuscitation from 1992–2024. We have also aimed to identify the remaining gaps in non-evidenced practice. Summary: Of the 22 procedures reviewed in the 2020 ILCOR recommendations, the evidence was either low, very low, or non-existing. The strength of recommendation is weak or non-existing for most topics discussed. Several knowledge gaps are also summarized. The special challenge for low- and middle-income countries (LMIC) is discussed. Key Messages: Newborn resuscitation is still not evidence-based, although great progress has been achieved the recent years. We have identified several knowledge gaps which should be prioritized in future research. The challenge of obtaining evidence-based knowledge from LMIC should be focused on in future research. [ABSTRACT FROM AUTHOR]

Mutations in GATA6 are associated with congenital heart disease, most notably conotruncal structural defects. However, how GATA6 regulates cardiac morphology during embryogenesis is undefined. We used knockout and conditional mutant zebrafish alleles to investigate the spatiotemporal role of gata6 during cardiogenesis. Loss of gata6 specifically impacts atrioventricular valve formation and recruitment of epicardium, with a prominent loss of arterial pole cardiac cells, including those of the ventricle and outflow tract. However, there are no obvious defects in cardiac progenitor cell specification, proliferation or death. Conditional loss of gata6 starting at 24 h is sufficient to disrupt the addition of late differentiating cardiomyocytes at the arterial pole, with decreased expression levels of anterior secondary heart field (SHF) markers spry4 and mef2cb. Conditional loss of gata6 in the endoderm is sufficient to phenocopy the straight knockout, resulting in a significant loss of ventricular and outflow tract tissue. Exposure to a Dusp6 inhibitor largely rescues the loss of ventricular cells in gata6−/− larvae. Thus, gata6 functions in endoderm are mediated by FGF signaling to regulate the addition of anterior SHF progenitor derivatives during heart formation. [ABSTRACT FROM AUTHOR]

Background: In vitro assessment is mandatory for artificial heart valve development. This study aims to investigate the effects of pulse duplicator features on valve responsiveness, conduct a sensitivity analysis across valve prosthesis types, and contribute on the development of versatile pulse duplicator systems able to perform reliable prosthetic aortic valve assessment under physiologic hemodynamic conditions. Methods: A reference pulse duplicator was established based on literature. Further optimization process led to new designs that underwent a parametric study, also involving different aortic valve prostheses. These designs were evaluated on criteria such as mean pressure differential and pulse pressure (assessed from high‐fidelity pressure measurements), valve opening and closing behavior, flow, and regurgitation. Finally, the resulting optimized setup was tested under five different hemodynamic settings simulating a range of physiologic and pathologic conditions. Results: The results show that both, pulse duplicator design and valve type significantly influence aortic and ventricular pressure, flow, and valve kinematic response. The optimal design comprised key features such as a compliance chamber and restrictor for diastolic pressure maintenance and narrow pulse pressure. Additionally, an atrial reservoir was included to prevent atrial–aortic interference, and a bioprosthetic valve was used in mitral position to avoid delayed valve closing effects. Conclusion: This study showed that individual pulse duplicator features can have a significant effect on valve's responsiveness. The optimized versatile pulse duplicator replicated physiologic and pathologic aortic valve hemodynamic conditions, serving as a reliable characterization tool for assessing and optimizing aortic valve performance. [ABSTRACT FROM AUTHOR]

Areas of social development are manifestations of Social Reality (SR) which defines possibilities and barriers to achieving a better life. An argument is made to unravel the "dialectic" of a broken society in the post-imperialist world. At the heart of Liberatory Development, one must recognize the lethality of coloniality and its vestiges that incubate a culture of dehumanizing subjugation, urbicidal inequality, and global injustice. A Kaleidoscopic view of human misery and our failure to address fundamental issues signifies the call for needed praxis. [ABSTRACT FROM AUTHOR]

Medulloblastoma (MB) is a rare cancer, although a more common pediatric brain tumor, affecting 350-500 children in the United States of America each year. MBs are classified as Grade IV neoplasms and divided into four subgroups, of which the Sonic Hedgehog-Activated (SHH-activated) group is responsible for most adult MBs. Thecurrent understanding of MB in adults and the genetic characteristics of all age groups lacks clarity. Thismeta-analysis aims to study, using the cBioPortal database, 170 genetic profiles of patients diagnosed with the SHH-activated subgroup of medulloblastoma and to revise how interactions of genes associated with MB contribute to the current understanding of the disease mechanisms and potential therapeutic targets. Thispaper uncovers the possible correlation between MB and diverse genetic alterations unrelated to MBs. The results showed insights into the neoplasm's formation and evolution, such as highlighting blood and blood vessel abnormalities, which can influence the tumor's metastasis potential. The e was also a high association between MB and histological, functional, and developmental abnormalities, including heart development problems, kidney problems, and other forms of cancer, revealing the genetic complexity of this tumor and suggesting possible clinical implications. [ABSTRACT FROM AUTHOR]

The aortic root is the segment of the aorta between the left ventricular outflow tract and the sinotubular junction of the ascending aorta, and, on one level, is merely a tube, with a valve at its base, dynamic structures below it, and notable for having the life-limiting coronary arteries originate within its sinuses. However, we propose that the perception of the aortic root has been historically grossly over-simplified by virtue of a bias towards its internal aspect, in terms of coronary ostia and subvalvar relationships through the fibrous skeleton and in so-doing a myocardial component on the external aspect has all but been ignored. This myocardial mass, a component of the left ventricular free wall, is sometimes termed the 'left ostial process' but appears to be rarely, if ever, considered by anatomists, cardiologists, and surgeons alike. By virtue of its direct continuity to the aortic root and proximal left coronary artery, it may have unique roles and, at the very least, deserves greater recognition and investigation. Herein, we propose that it could play a crucial role in cardiac embryology including coronary dominance, and may afford a physiological advantage, to the extent that it may have been selected for in evolutionary terms. [ABSTRACT FROM AUTHOR]

Human cardiac development and regeneration modeling are crucial areas of research that hold immense promise for advancing regenerative medicine and treating cardiovascular diseases. Understanding the intricate process of cardiac development, from the formation of the primitive heart tube to the maturation of the fetal heart, provides insights into potential therapeutic strategies for cardiac regeneration. This article explores the key stages of cardiac development, factors influencing cardiac regeneration, current models for studying regenerative processes, challenges and opportunities in regenerative medicine, future directions in cardiac development research, clinical applications of regenerative modeling, and the implications for healthcare. By delving into these aspects, researchers and healthcare professionals can gain a deeper understanding of how to harness the regenerative potential of the human heart for improved patient outcomes. [ABSTRACT FROM AUTHOR]

AbstractThe creation, dissemination, and application of knowledge are crucial for achieving sustainable development and have been at the heart of international development efforts since World War II. In conventional international development cooperation, the Global North is portrayed as the provider of knowledge and material assistance, with the South often perceived as a more passive receiver. This approach perpetuates hierarchical knowledge-power relations, as what is considered the ‘best practices’ are usually based on experiences, ideologies, and ideals from the North. This paper critically examines the current role of Western development actors as providers of knowledge and policy, specifically in the formulation of good governance for natural gas resources in Tanzania. Following significant offshore natural gas discoveries between 2010–2015, Tanzania has garnered the attention of international energy companies, foreign donors, technical advisors, and consultants, all offering guidance and capacity-building expertise to ready the country for production. Drawing on interviews with key actors supported by secondary sources, this analysis depicts how hierarchical knowledge relations persist, but also highlights the contested and evolving nature of what constitutes good governance of natural gas resources. The paper underscores how context matters in petroleum resource governance and, more broadly, the necessity for contextualising knowledge in international development cooperation. [ABSTRACT FROM AUTHOR]

From birth to adulthood, the mammalian heart grows primarily through increasing cardiomyocyte (CM) size, which is known as maturational hypertrophic growth. The Hippo-YAP signaling pathway is well known for regulating heart development and regeneration, but its roles in CM maturational hypertrophy have not been clearly addressed. Vestigial-like 4 (VGLL4) is a crucial component of the Hippo-YAP pathway, and it functions as a suppressor of YAP/TAZ, the terminal transcriptional effectors of this signaling pathway. To develop an in vitro model for studying CM maturational hypertrophy, we compared the biological effects of T3 (triiodothyronine), Dex (dexamethasone), and T3/Dex in cultured neonatal rat ventricular myocytes (NRVMs). The T3/Dex combination treatment stimulated greater maturational hypertrophy than either the T3 or Dex single treatment. Using T3/Dex treatment of NRVMs as an in vitro model, we found that activation of VGLL4 suppressed CM maturational hypertrophy. In the postnatal heart, activation of VGLL4 suppressed heart growth, impaired heart function, and decreased CM size. On the molecular level, activation of VGLL4 inhibited the PI3K-AKT pathway, and disrupting VGLL4 and TEAD interaction abolished this inhibition. In conclusion, our data suggest that VGLL4 suppresses CM maturational hypertrophy by inhibiting the YAP/TAZ-TEAD complex and its downstream activation of the PI3K-AKT pathway. [ABSTRACT FROM AUTHOR]

During early embryonic development, the heart undergoes a remarkable and complex transformation, acquiring its iconic four-chamber structure whilst concomitantly contracting to maintain its essential function. The emergence of cardiac form and function involves intricate interplays between molecular, cellular, and biomechanical events, unfolding with precision in both space and time. The dynamic morphological remodelling of the developing heart renders it particularly vulnerable to congenital defects, with heart malformations being the most common type of congenital birth defect (-35% of all congenital birth defects). This mini-review aims to give an overview of the morphogenetic processes which govern early heart formation as well as the dynamics and mechanisms of early cardiac function. Moreover, we aim to highlight some of the interplay between these two processes and discuss how recent findings and emerging techniques/models offer promising avenues for future exploration. In summary, the developing heart is an exciting model to gain fundamental insight into the dynamic relationship between form and function, which will augment our understanding of cardiac congenital defects and provide a blueprint for potential therapeutic strategies to treat disease. [ABSTRACT FROM AUTHOR]

Autonomic control of heart rate is well known in adult subjects, but limited data are available on the development of the heart rate control during childhood and adolescence. Continuous 12-lead electrocardiograms were recorded in 1045 healthy children and adolescents (550 females) aged 4 to 19 years during postural manoeuvres involving repeated 10-min supine, unsupported sitting, and unsupported standing positions. In each position, heart rate was measured, and heart rate variability indices were evaluated (SDNN, RMSSD, and high (HF) and low (LF) frequency components were obtained). Quasi-normalized HF frequency components were defined as qnHF = HF/(HF + LF). These measurements were, among others, related to age using linear regressions. In supine position, heart rate decreases per year of age were significant in both sexes but lower in females than in males. In standing position, these decreases per year of age were substantially lowered. RMSSD and qnHF indices were independent of age in supine position but significantly decreased with age in sitting and standing positions. Correspondingly, LF/HF proportions showed steep increases with age in sitting and standing positions but not in the supine position. The study suggests that baseline supine parasympathetic influence shows little developmental changes during childhood and adolescence but that in young children, sympathetic branch is less responsive to vagal influence. While vagal influences modulate cardiac periods in young and older children equally, they are less able to suppress the sympathetic influence in younger children. [ABSTRACT FROM AUTHOR]

The sarcolemmal Ca2+ efflux pathways, Na+-Ca2+-exchanger (NCX) and Ca2+-ATPase (PMCA), play a crucial role in the regulation of intracellular Ca2+ load and Ca2+ transient in cardiomyocytes. The distribution of these pathways between the t-tubular and surface membrane of ventricular cardiomyocytes varies between species and is not clear in human. Moreover, several studies suggest that this distribution changes during the development and heart diseases. However, the consequences of NCX and PMCA redistribution in human ventricular cardiomyocytes have not yet been elucidated. In this study, we aimed to address this point by using a mathematical model of the human ventricular myocyte incorporating t-tubules, dyadic spaces, and subsarcolemmal spaces. Effects of various combinations of t-tubular fractions of NCX and PMCA were explored, using values between 0.2 and 1 as reported in animal experiments under normal and pathological conditions. Small variations in the action potential duration (≤ 2%), but significant changes in the peak value of cytosolic Ca2+ transient (up to 17%) were observed at stimulation frequencies corresponding to the human heart rate at rest and during activity. The analysis of model results revealed that the changes in Ca2+ transient induced by redistribution of NCX and PMCA were mainly caused by alterations in Ca2+ concentrations in the subsarcolemmal spaces and cytosol during the diastolic phase of the stimulation cycle. The results suggest that redistribution of both transporters between the t-tubular and surface membranes contributes to changes in contractility in human ventricular cardiomyocytes during their development and heart disease and may promote arrhythmogenesis. [Display omitted] • Sarcolemma of cardiac ventricular cells creates a complex net of t-tubules. • T-tubular fractions of NCX and PMCA in human ventricular cardiomyocytes are unclear. • Membrane localisation of NCX and PMCA in cardiomyocytes is altered in heart diseases. • A novel model of human ventricular cardiomyocytes with submembrane spaces was used. • Membrane redistribution of NCX and PMCA affects cell inotropy and arrhythmogenesis. [ABSTRACT FROM AUTHOR]

Human induced pluripotent stem cell (hiPSC)‐derived cardiac organoids (COs) have shown great potential in modelling human heart development and cardiovascular diseases, a leading cause of global death. However, several limitations such as low reproducibility, limited vascularization and difficulty in formation of cardiac chamber were yet to be overcome. We established a new method for robust generation of COs, via combination of methodologies of hiPSC‐derived vascular spheres and directly differentiated cardiomyocytes from hiPSCs, and investigated the potential application of human COs in cardiac injury modelling and drug evaluation. The human COs we built displayed a vascularized and chamber‐like structure, and hence were named vaschamcardioids (vcCOs). These vcCOs exhibited approximately 90% spontaneous beating ratio. Single‐cell transcriptomics identified a total of six cell types in the vcCOs, including cardiomyocytes, cardiac precursor cells, endothelial cells, fibroblasts, etc. We successfully recaptured the processes of cardiac injury and fibrosis in vivo on vcCOs, and showed that the FDA‐approved medication captopril significantly attenuated cardiac injury‐induced fibrosis and functional disorders. In addition, the human vcCOs exhibited an obvious drug toxicity reaction to doxorubicin in a dose‐dependent manner. We developed a three‐step method for robust generation of chamber‐like and vascularized complex vcCOs, and our data suggested that vcCOs might become a useful model for understanding pathophysiological mechanisms of cardiovascular diseases, developing intervention strategies and screening drugs. [ABSTRACT FROM AUTHOR]

• Combined genetic-pharmacologic ADAMTS1 and ADAMTS5 inactivation in mice. • Degradomics identification of putative ADAMTS1 and ADAMTS5 substrates. • A requirement for versican proteolysis and glypican-6 in heart development. • Novel roles for ADAMTS1, ADAMTS5 and glypican-6 in hedgehog signaling in the heart. Extracellular matrix remodeling mechanisms are understudied in cardiac development and congenital heart defects. We show that matrix-degrading metalloproteases ADAMTS1 and ADAMTS5, are extensively co-expressed during mouse cardiac development. The mouse mutants of each gene have mild cardiac anomalies, however, their combined genetic inactivation to elicit cooperative roles is precluded by tight gene linkage. Therefore, we coupled Adamts1 inactivation with pharmacologic ADAMTS5 blockade to uncover stage-specific cooperative roles and investigated their potential substrates in mouse cardiac development. ADAMTS5 blockade was achieved in Adamts1 null mouse embryos using an activity-blocking monoclonal antibody during distinct developmental windows spanning myocardial compaction or cardiac septation and outflow tract rotation. Synchrotron imaging, RNA in situ hybridization, immunofluorescence microscopy and electron microscopy were used to determine the impact on cardiac development and compared to Gpc6 and ADAMTS-cleavage resistant versican mutants. Mass spectrometry-based N-terminomics was used to seek relevant substrates. Combined inactivation of ADAMTS1 and ADAMTS5 prior to 12.5 days of gestation led to dramatic accumulation of versican-rich cardiac jelly and inhibited formation of compact and trabecular myocardium, which was also observed in mice with ADAMTS cleavage-resistant versican. Combined inactivation after 12.5 days impaired outflow tract development and ventricular septal closure, generating a tetralogy of Fallot-like defect. N-terminomics of combined ADAMTS knockout and control hearts identified a cleaved glypican-6 peptide only in the controls. ADAMTS1 and ADAMTS5 expression in cells was associated with specific glypican-6 cleavages. Paradoxically, combined ADAMTS1 and ADAMTS5 inactivation reduced cardiac glypican-6 and outflow tract Gpc6 transcription. Notably, Gpc6 −/− hearts demonstrated similar rotational defects as combined ADAMTS inactivated hearts and both had reduced hedgehog signaling. Thus, versican proteolysis in cardiac jelly at the canonical Glu441-Ala442 site is cooperatively mediated by ADAMTS1 and ADAMTS5 and required for proper ventricular cardiomyogenesis, whereas, reduced glypican-6 after combined ADAMTS inactivation impairs hedgehog signaling, leading to outflow tract malrotation. [ABSTRACT FROM AUTHOR]

The Dlk1-Dio3 domain is important for normal embryonic growth and development. The heart is the earliest developing and functioning organ of the embryo. In this study, we constructed a transcriptional termination model by inserting termination sequences and clarified that the lack of long non-coding RNA (lncRNA) expression in the Dlk1-Dio3 domain caused the death of maternal insertion mutant (MKI) and homozygous mutant (HOMO) mice starting from E13.5. Parental insertion mutants (PKI) can be born and grow normally. Macroscopically, dying MKI and HOMO embryos showed phenomena such as embryonic edema and reduced heart rate. Hematoxylin and eosin (H.E.) staining showed thinning of the myocardium in MKI and HOMO embryos. In situ hybridization (IHC) and quantitative reverse-transcription polymerase chain reaction (qRT-PCR) showed downregulation of lncGtl2, Rian, and Mirg expression in MKI and HOMO hearts. The results of single-cell RNA sequencing (scRNA-Seq) analysis indicated that the lack of lncRNA expression in the Dlk1-Dio3 domain led to reduced proliferation of epicardial cells and may be an important cause of cardiac dysplasia. In conclusion, this study demonstrates that Dlk1-Dio3 domain lncRNAs play an integral role in ventricular development. [ABSTRACT FROM AUTHOR]

The prevalence of e‐cigarette use among young adults in the USA is high (14%). Although the majority of users plan to quit vaping, the motivation to make a quit attempt is low and available support during a quit attempt is limited. Using wearable sensors to collect physiological data (eg, heart rate) holds promise for capturing the right timing to deliver intervention messages. This study aims to fill the current knowledge gap by proposing statistical methods to (1) de‐noise beat‐to‐beat interval (BBI) data from smartwatches worn by 12 young adult regular e‐cigarette users for 7 days; and (2) summarize the de‐noised data by event and control segments. We also conducted a comprehensive review of conventional methods for summarizing heart rate variability (HRV) and compared their performance with the proposed method. The results show that the proposed singular spectrum analysis (SSA) can effectively de‐noise the highly variable BBI data, as well as quantify the proportion of total variation extracted. Compared to existing HRV methods, the proposed second order polynomial model yields the highest area under the curve (AUC) value of 0.76 and offers better interpretability. The findings also indicate that the average heart rate before vaping is higher and there is an increasing trend in the heart rate before the vaping event. Importantly, the development of increasing heart rate observed in this study implies that there may be time to intervene as this physiological signal emerges. This finding, if replicated in a larger scale study, may inform optimal timings for delivering messages in future intervention. [ABSTRACT FROM AUTHOR]

Due to the cancer therapy-related cardiovascular toxicity, heart failure following cancer therapy has a significant mortality rate. Gene-targeted therapy promotes the re-entry of existing cardiomyocytes into the cell cycle to achieve myocardial regeneration, which is a promising strategy for preventing and treating heart failure after myocardial infarction. Circular RNAs (circRNAs) are considered as potential targets for myocardial regeneration due to their strong stability, resistance to degradation, and potential role in heart development and cardiovascular diseases. By comparing the myocardial tissue of mice in the sham operation group and the Doxorubicin therapy group (DOX), we observed a significant decrease in Cirsorbs expression in the DOX group. Cirsorbs was predominantly localized in cardiomyocytes and exhibited high conservation. Subsequent investigations revealed that Cirsorbs could promote myocardial proliferation and inhibit myocardial apoptosis. Mechanistic studies further demonstrated that Cirsorbs could bind to miR99 and reduce its expression level. Meanwhile, miR99 was found to bind to GATA4 mRNA and decrease its expression level. The binding of Cirsorbs to miR99 alleviated the repression of miR99, thereby enhancing GATA4 expression and the transcription of downstream cyclin A2 and cyclin E1. This, in turn, increased cardiomyocyte proliferation and reduced apoptosis. In conclusion, Cirsorbs holds promise as an effective target for myocardial regeneration in reducing cancer therapy-related cardiovascular toxicity. [ABSTRACT FROM AUTHOR]

Epicardial epithelial-to-mesenchymal transition (EMT) plays a pivotal role in both heart development and injury response and involves dynamic cellular changes that are essential for cardiogenesis and myocardial repair. Specifically, epicardial EMT is a crucial process in which epicardial cells lose polarity, migrate into the myocardium, and differentiate into various cardiac cell types during development and repair. Importantly, following EMT, the epicardium becomes a source of paracrine factors that support cardiac growth at the last stages of cardiogenesis and contribute to cardiac remodeling after injury. As such, EMT seems to represent a fundamental step in cardiac repair. Nevertheless, endogenous EMT alone is insufficient to stimulate adequate repair. Redirecting and amplifying epicardial EMT pathways offers promising avenues for the development of innovative therapeutic strategies and treatment approaches for heart disease. In this review, we present a synthesis of recent literature highlighting the significance of epicardial EMT reactivation in adult heart disease patients. [ABSTRACT FROM AUTHOR]

Aims βII spectrin is a cytoskeletal protein known to be tightly linked to heart development and cardiovascular electrophysiology. However, the roles of βII spectrin in cardiac contractile function and pathological post-myocardial infarction remodelling remain unclear. Here, we investigated whether and how βII spectrin, the most common isoform of non-erythrocytic spectrin in cardiomyocytes, is involved in cardiac contractile function and ischaemia/reperfusion (I/R) injury. Methods and results We observed that the levels of serum βII spectrin breakdown products (βII SBDPs) were significantly increased in patients with acute myocardial infarction (AMI). Concordantly, βII spectrin was degraded into βII SBDPs by calpain in mouse hearts after I/R injury. Using tamoxifen-inducible cardiac-specific βII spectrin knockout mice, we found that deletion of βII spectrin in the adult heart resulted in spontaneous development of cardiac contractile dysfunction, cardiac hypertrophy, and fibrosis at 5 weeks after tamoxifen treatment. Moreover, at 1 week after tamoxifen treatment, although spontaneous cardiac dysfunction in cardiac-specific βII spectrin knockout mice had not developed, deletion of βII spectrin in the heart exacerbated I/R-induced cardiomyocyte death and heart failure. Furthermore, restoration of βII spectrin expression via adenoviral small activating RNA (saRNA) delivery into the heart reduced I/R injury. Immunoprecipitation coupled with mass spectrometry (IP–LC–MS/MS) analyses and functional studies revealed that βII spectrin is indispensable for mitochondrial complex I activity and respiratory function. Mechanistically, βII spectrin promotes translocation of NADH:ubiquinone oxidoreductase 75-kDa Fe-S protein 1 (NDUFS1) from the cytosol to mitochondria by crosslinking with actin filaments (F-actin) to maintain F-actin stability. Conclusion βII spectrin is an essential cytoskeletal element for preserving mitochondrial homeostasis and cardiac function. Defects in βII spectrin exacerbate cardiac I/R injury. [ABSTRACT FROM AUTHOR]

During heart development, the embryonic ventricle becomes enveloped by the epicardium, which adheres to the outer apical surface of the heart. This is concomitant with onset of ventricular trabeculation, where a subset of cardiomyocytes lose apicobasal polarity and delaminate basally from the ventricular wall. Llgl1 regulates the formation of apical cell junctions and apicobasal polarity, and we investigated its role in ventricular wall maturation. We found that llgl1 mutant zebrafish embryos exhibit aberrant apical extrusion of ventricular cardiomyocytes. While investigating apical cardiomyocyte extrusion, we identified a basal-to-apical shift in laminin deposition from the internal to the external ventricular wall. We find that epicardial cells express several laminin subunits as they adhere to the ventricle, and that the epicardium is required for laminin deposition on the ventricular surface. In llgl1 mutants, timely establishment of the epicardial layer is disrupted due to delayed emergence of epicardial cells, resulting in delayed apical deposition of laminin on the ventricular surface. Together, our analyses reveal an unexpected role for Llgl1 in correct timing of epicardial development, supporting integrity of the ventricular myocardial wall. [ABSTRACT FROM AUTHOR]

Transcription initiates at the core promoter, which contains distinct core promoter elements. Here, we highlight the complexity of transcriptional regulation by outlining the effect of core promoterdependent regulation on embryonic development and the proper function of an organism. We demonstrate in vivo the importance of the downstream core promoter element (DPE) in complex heart formation in Drosophila. Pioneering a novel approach using both CRISPR and nascent transcriptomics, we show the effects of mutating a single core promoter element within the natural context. Specifically, we targeted the downstream core promoter element (DPE) of the endogenous tin gene, encoding the Tinman transcription factor, a homologue of human NKX2-5 associated with congenital heart diseases. The 7 bp substitution mutation results in massive perturbation of the Tinman regulatory network that orchestrates dorsal musculature, which is manifested as physiological and anatomical changes in the cardiac system, impaired specific activity features, and significantly compromised viability of adult flies. Thus, a single motif can have a critical impact on embryogenesis and, in the case of DPE, functional heart formation. Transcription initiates at the core promoter, which contains distinct core promoter elements. Here, we highlight the complexity of transcriptional regulation by outlining the effect of core promoterdependent regulation on embryonic development and the proper function of an organism. We demonstrate in vivo the importance of the downstream core promoter element (DPE) in complex heart formation in Drosophila. Pioneering a novel approach using both CRISPR and nascent transcriptomics, we show the effects of mutating a single core promoter element within the natural context. Specifically, we targeted the downstream core promoter element (DPE) of the endogenous tin gene, encoding the Tinman transcription factor, a homologue of human NKX2-5 associated with congenital heart diseases. The 7 bp substitution mutation results in massive perturbation of the Tinman regulatory network that orchestrates dorsal musculature, which is manifested as physiological and anatomical changes in the cardiac system, impaired specific activity features, and significantly compromised viability of adult flies. Thus, a single motif can have a critical impact on embryogenesis and, in the case of DPE, functional heart formation. [ABSTRACT FROM AUTHOR]

The cardiac extracellular matrix (cECM) is fundamental for organ morphogenesis and maturation, during which time it undergoes remodeling, yet little is known about whether mechanical forces generated by the heartbeat regulate this remodeling process. Using zebrafish as a model and focusing on stages when cardiac valves and trabeculae form, we found that altering cardiac contraction impairs cECM remodeling. Longitudinal volumetric quantifications in wildtype animals revealed region-specific dynamics: cECM volume decreases in the atrium but not in the ventricle or atrioventricular canal. Reducing cardiac contraction resulted in opposite effects on the ventricular and atrial ECM, whereas increasing the heart rate affected the ventricular ECM but had no effect on the atrial ECM, together indicating that mechanical forces regulate the cECM in a chamber-specific manner. Among the ECM remodelers highly expressed during cardiac morphogenesis, we found one that was upregulated in non-contractile hearts, namely tissue inhibitor of matrix metalloproteinase 2 (timp2). Loss- and gain-of-function analyses of timp2 revealed its crucial role in cECM remodeling. Altogether, our results indicate that mechanical forces control cECM remodeling in part through timp2 downregulation. [ABSTRACT FROM AUTHOR]

Semaphorin6A (Sema6A) is a repulsive guidance molecule that plays many roles in central nervous system, heart and bone development, as well as immune system responses and cell signaling in cancer. Loss of Sema6A or its receptor PlexinA2 in zebrafish leads to smaller eyes and improper retinal patterning. Here, we investigate a potential role for the Sema6A intracellular domain in zebrafish eye development and dissect which phenotypes rely on forward signaling and which rely on reverse signaling. We performed rescue experiments on zebrafish Sema6A morphants with either full-length Sema6A (Sema6A-FL) or Sema6A lacking its intracellular domain (Sema6A-ΔC). We identified that the intracellular domain is not required for eye size and retinal patterning, however it is required for retinal integrity, the number and end feet strength of Müller glia and protecting against retinal cell death. This novel function for the intracellular domain suggests a role for Sema6A reverse signaling in zebrafish eye development. [ABSTRACT FROM AUTHOR]

BACKGROUND: The second heart field is crucial for the development of the embryonic heart. Abnormal development of the second heart field can result in multiple cardiac malformations. After Cx43 gene knockout, reduced formation and proliferation of cells of the second heart field can be observed, but the specific reason remains unclear. OBJECTIVE: (1) To determine whether β-catenin, Smo and Cx43 were co-expressed in the second heart field and the endoderm, we observed the expression patterns of these proteins. (2) To explore whether Cx43 interacts with the Wnt/β-catenin pathway or the Shh pathway in the development of the second heart field. METHODS: Serial paraffin sections of the mouse embryos at embryonic days 10-12 were selected for immunohistochemical staining, hematoxylin-eosin staining and immunofluorescence staining. The primitive gut of mouse embryos at embryonic day 11 was separated for western blot assay and co-immunoprecipitation. RESULTS AND CONCLUSION: (1) Cx43 and Isl1 were co-expressed in some mesenchymal cells on the ventral side of the foregut and dorsal wall of the pericardial cavity of mouse embryos at embryonic days 10-12; Isl1 positive cells increased while Cx43 positive cells increased. (2) Cx43 and β-catenin were co)expressed in the ventral part of the endoderm at embryonic days 10-12. (3) Cx43 and Smo were co-expressed in the endoderm at embryonic days 10-12. (4) The co-immunoprecipitation results confirmed that there was an interaction between Cx43 and β-catenin, which suggested that Cx43 interacted with β-catenin to participate in the development of the second heart field. [ABSTRACT FROM AUTHOR]

The article discusses the complexity of human life development. Topics mentioned include the capacity of the brain for growth and refinement, the main reasons why human life is sacred, the divine role of God in creating DNA, muscles, enzymes and nerves in the womb and the importance of the heart in the development of human embryo.