Cardiac Development Research Articles

Endothelial cell-cardiomyocyte cross-talk: understanding bidirectional paracrine signaling in cardiovascular homeostasis and disease.

To maintain homeostasis in the heart, endothelial cells and cardiomyocytes engage in dynamic cross-talk through paracrine signals that regulate both cardiac development and function. Here, we review the paracrine signals that endothelial cells release to regulate cardiomyocyte growth, hypertrophy and contractility, and the factors that cardiomyocytes release to influence angiogenesis and vascular tone. Dysregulated communication between these cell types can drive pathophysiology of disease, as seen in ischemia-reperfusion injury, diabetes, maladaptive hypertrophy, and chemotherapy-induced cardiotoxicity. Investingating the role of cross-talk is critical in developing an understanding of tissue homeostasis, regeneration, and disease pathogenesis, with the potential to identify novel targets for diagnostic and therapeutic purposes.

The effect of tris (1,3-dichloro-2-propyl) phosphate on the early embryonic heart development of Oryzias melastigma

The flame retardant tri (1, 3-dichloro-2-propyl) phosphate (TDCIPP) is widely present in environmental media and organisms. People have paid much attention to the growth and developmental toxicity of TDCIPP, but there is little information about its cardiotoxicity and potential mechanisms. In this study, marine medaka (Oryzias melastigma) embryos were exposed to TDCIPP solutions (0, 0.05, 0.5, 5, and 50 μg/L) for 21 days to investigate the adverse effects of TDCIPP on cardiac development. The results showed that TDCIPP exposure altered the heart rate at different stages of embryonic development. In addition, 50 μg/L TDCIPP resulted in increased sinus venosus (SV)–bulbus arteriosus (BA) distance, pericardial cysts, and cardiac linearization in newly hatched fish. During embryonic development, the expression level of key genes regulating cardiac development is disturbed. The early stage of cardiac development is the sensitive window period for the toxic effects of TDCIPP. Oxidative stress was observed in newly hatched juveniles, but no significant lipid peroxidation damage was observed. In addition, vitellogenin (VTG) levels in juvenile fish were significantly reduced. Our results show that TDCIPP exposure induces cardiotoxicity in marine medaka embryos, which is induced in the early stages and promotes heart defects by amplifying inflammatory responses at a later stage.

In Vitro Vascularization Improves In Vivo Functionality of Human Engineered Cardiac Tissues

Engineered human cardiac tissues hold great promise for disease modeling, drug development, and regenerative therapy. For regenerative applications, successful engineered tissue engraftment in vivo requires rapid vascularization and blood perfusion post-implantation. In the present study, we engineered highly functional, vascularized cardiac tissues (“cardiopatches”) by co-culturing human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) and endothelial cells (hiPSC-ECs) in optimized serum-free media. The vascularized cardiopatches displayed stable capillary networks over 4 weeks of culture, the longest reported in the field, while maintaining high contractile stress (>15 mN/mm2) and fast conduction velocity (>20 cm/s). Robustness of the method was confirmed using two distinct hiPSC-EC sources. Upon implantation into dorsal-skinfold chambers in immunocompromised mice, in vitro vascularized cardiopatches exhibited improved angiogenesis compared to avascular implants. Significant lumenization of the engineered human vasculature and anastomosis with host mouse vessels yielded the formation of hybrid human-mouse capillaries and robust cardiopatch perfusion by blood. Moreover, compared to avascular tissues, the implanted vascularized cardiopatches exhibited significantly higher conduction velocity and Ca2+ transient amplitude, longitudinally monitored in live mice for the first time. Overall, we demonstrate successful 4-week vascularization of engineered human cardiac tissues without loss of function in vitro, which promotes tissue functionality upon implantation in vivo. Statement of SignificanceComplex interactions between cardiac muscle fibers and surrounding capillaries are critical for everyday function of the heart. Tissue engineering is a powerful method to recreate functional cardiac muscle and its vascular network, which are both lost during a heart attack. Our study demonstrates in vitro engineering of dense capillary networks within highly functional engineered heart tissues that successfully maintain the structure, electrical, and mechanical function long-term. In mice, human capillaries from these engineered tissues integrate with host mouse capillaries to allow blood perfusion and support improved implant function. In the future, the developed vascularized engineered heart tissues will be used for in vitro studies of cardiac development and disease and as a potential regenerative therapy for heart attack.

Novel association of LBX1 mutation with tetralogy of Fallot and hypertrophic cardiomyopathy: implications for cardiac development.

Tetralogy of Fallot (TOF) and hypertrophic cardiomyopathy (HCM) are common types of congenital heart disease with unique pathophysiologic features. Mutations in LBX1, a key regulator of muscle precursor cell migration, may disrupt these critical developmental processes, resulting in severe developmental abnormalities. This case reports on a 4-year-old girl diagnosed with both TOF and HCM. Genetic analysis revealed iUPI-F (uniparental disomy) on the entire chromosome 10, with a c.808G > A (p. Glu270Lys) pure mutation in the LBX1. This patient exhibited both TOF and HCM with mutations in the LBX1 gene, suggesting a potentially novel genetic link. This case study emphasizes the need for further studies on the function of the LBX1 gene in cardiac development and its potential impact on TOF and HCM.

Fine particulate matter‑induced cardiac developmental toxicity (Review).

Fine particulate matter (PM2.5) has become an important risk factor threatening human health. Epidemiological and toxicological investigations have revealed that PM2.5 not only leads to cardiovascular dysfunction, but it also gives rise to various adverse health effects on the human body, such as cardiovascular and cerebrovascular diseases, cancers, neurodevelopmental disorders, depression and autism. PM2.5 is able to penetrate both respiratory and placental barriers, thereby resulting in negative effects on fetal development. A large body of epidemiological evidences has suggested that gestational exposure to PM2.5 increases the incidence of congenital diseases in offspring, including congenital heart defects. In addition, animal model studies have revealed that gestational exposure to PM2.5 can disrupt normal heart development in offspring, although the potential molecular mechanisms have yet to be fully elucidated. The aim of the present review was to provide a brief overview of what is currently known regarding the molecular mechanisms underlying cardiac developmental toxicity in offspring induced by gestational exposure to PM2.5.

Intronic regulatory sequences regulate epicardial gene expression and EMT during heart development

Abstract Background During organogenesis, cells from the outer layer of the heart, the epicardium, undergo epithelial-to-mesenchymal transition (EMT), contributing essential paracrine signals and different cell types to the growing heart. Epicardial cells are integral to heart regeneration in lower vertebrates and neonatal mammalian injured hearts. That said, prospects to harness the epicardium for therapeutic applications to effect adult heart repair, heavily depend on improved insight into its intrinsic properties during heart development. Purpose Cell fate decisions underpinning EMT are directed by transcription factors such as Wilms’ tumour 1 (WT1). Whilst a requirement for Wt1 in heart development is widely accepted, the upstream regulatory mechanisms underpinning its activation remain elusive. Our previous research has led to the identification of two intronic evolutionary conserved regions (ECRs) shared between mouse and human, located within intron 1 of the Wt1 locus, i.e. +4.0kbECR and +5.8kbECR. We hypothesised these regulatory sequences direct locus activation and EMT to support normal heart development. Methods & Results Here, we used CRISPR/Cas9 gene-editing technology to generate mice carrying a sequence deletion containing one ECR (Wt1Δ+4.0kbECR and Wt1Δ+5.8kbECR mice) or a deletion comprising both ECRs (Wt1Δ+4-5.8kbECR mouse). Extensive survival analysis, high-resolution episcopic microscopy (HREM), qPCR, immunostaining, confocal microscopy and epicardial explants were used to characterise heart formation in these models. Mendelian ratios indicated an overall underrepresentation of Wt1ΔECR/ΔECR mutants recovered in the offspring arising from heterozygous inter-crosses. HREM revealed smaller hearts, incidence of myocardial non-compaction and spongy interventricular septum with muscular or membranous ventricular septum defects, tricuspid hypoplasia and enlarged aortic valves, as well as abnormal formation/patterning of coronary artery stems in ΔECR/ΔECR hearts. Expression of Wt1 was markedly reduced in ΔECR/ΔECR hearts, but not in the kidneys, suggesting intronic enhancers are cardiac-specific. Whole-mount and tissue-section immunostaining combined with confocal microscopy revealed abnormal coronary vessel and innervation extension and patterning along the subepicardial space, as well as reduced epicardial EMT and myocardial non-compaction/hyper-trabeculation in Wt1ΔECR/ΔECR hearts. Conclusions Together, we demonstrated a requirement for novel intronic enhancers regulating Wt1 locus activity and impacting on essential epicardial EMT and associated biological processes during normal heart development. Importantly, observation of septum and aortic valve defects in ΔECR mutants suggests an hitherto unrecognised role for WT1/epicardial EMT and opens new avenues of research to improve our understanding of congenital heart disease that affects at least 1:150 live births, with remarkably two thirds of cases having unknown aetiology.

Reduced Sox7 contributes to abnormal valve development resulting in congenital aortic stenosis

Abstract Background Abnormal valve development is the most common congenital heart malformation. During valve remodeling, abnormal changes in valve cell proliferation, apoptosis, and extracellular matrix synthesis affect valve development, resulting in malformations. The molecular mechanisms underlying pathophysiology of aortic stenos is remain unclear. Purpose We would like to explore how Sox7 is involved in aortic valve development. Methods and Results We proved Sox7 was mainly expressed in endocardial and mesenchymal cells of aortic valves by immunofluorescence staining determined by at different stages of mice (E10.5～8 weeks) and human embryos and RNA-seq of E9.5 mouse embryonic hearts. We constructed a conditional Sox7 floxed allele in endothelial cells using an endocardial specific Cre. Echocardiography data showed that Nfat-KO mice had increased blood velocity, pressure gradient across aortic valves, left ventricular mass and dilated aortic roots. Then, HE and Sirius red staining to examine histological changes in aortic valves of Nfat-KO mice were performed, and we observed a remarkable increase in the size and increased staining of fibrotic cells in aortic valves of KO mice. Next, we collected embryonic hearts of Sox7 CNC-specific knockout mice (WNT1-KO) and controls at E16.5. According to HE staining results and echocardiography analysis, there was no difference in aortic valves between WNT1-KO mice and controls. Meanwhile, we collected Nfat-KO mice and control embryos at E11.5 days. HE staining results showed that EndMT process was not impaired. Interestingly, leaflets and cusps of Nfat-KO mice showed significantly augmented proliferation levels, decreased apoptosis levels, and calcium deposition in fibrin layer. A significant decrease in MMP9 levels were observed in both mRNA and protein levels. Co-transfection of Sox7-expressing vector and MMP9 luciferase in MEEC suggested that Sox7 significantly activated MMP9. We used adenovirus to overexpress Sox7 in valvular interstitial cells. Compared with that in control group, the Sox7-overexpression group increased protein level of MMP9 and cleaved caspase-3, and increased Tunel-positive rate and lower Ki-67 positive rate. Finally, we detected expression of Sox7 protein in human fetal aortic valves derived from patients with aortic stenosis using immunofluorescence. The results demonstrated that the number of Sox7 positive mesenchymal cells in human fetal aortic valves of patients was significantly lower than that in control group. Conclusion We demonstrated that targeted inactivation of Sox7 in the endocardium of mice affects valve development and leads to aortic stenosis. Mechanistically, no influence of Sox7 on the EndMT process of the OFT cushion. Moreover, CNC-derived Sox7 was not involved in aortic valve development. Interestingly, we found that Sox7 regulated ECM remodeling through matrix MMP9 and Sox7 had an impact on apoptosis, proliferation, and calcification.

Genetic and phenotypic architecture of biventricular trabeculation

Abstract Introduction Cardiac trabeculae form a network of muscular strands that line the inner surfaces of the heart, and their development involves molecular pathways that regulate structural complexity. Excessive or hypertrabeculation occurs as part of normal variation in apparently healthy individuals, as an adaptation to altered loading conditions, and is observed in patients with cardiomyopathies (CMs) and heart failure (HF). Purpose In adults, trabeculation is not a prognostic factor independent of the underlying myocardial disease but may play a role in the natural history of ventricular remodelling. We sought to (i) understand the genetic and non-genetic determinants of trabeculation, (ii) understand its role in the causality of disease, and (iii) evaluate trabeculation as a biomarker for diagnosis and stratification. Methods We report genes with a burden of rare variants and novel common variant associations across the allele frequency spectrum for biventricular trabecular morphology in 47,803 participants of the UK Biobank using fractal dimension analysis of cardiac imaging (Figure 1). We assessed environmental modifiers of trabecular morphology, correlation with cardiac traits, phenome-wide association studies, and the relationship with the progression of CMs and HF. Results We identified a burden of trabeculation-associated rare variants in genes that regulate myocardial contractility and cardiac development and GWAS identified novel loci near genes implicated in CMs, conduction traits, and signalling pathways that define the early development of trabeculation. For example, we identified 56 genes with a burden of rare variants and 68 novel loci from GWAS (e.g., CASQ2, CACNA1C, MYBPC3, MYH7, NKX2-5, NOTCH1, TBX20) for the left ventricle. The strongest imaging relationships with trabeculation were with measures of volume and strain. Modifiers of trabeculation included African ancestry, alcohol intake, and physical activity. Carriers of CM-associated pathogenic variants had increased trabeculation. Of participants with CM reported after imaging, 25% had hypertrabeculation on imaging and hypertrabeculation was a risk factor for a subsequent diagnosis of HF (HR=1.3), mitral valve disorders (HR=1.4), bundle branch block (HR=1.2). Comparisons of biventricular trabeculation showed similarities in trabeculation across the ventricles in CM. Reduced right ventricular trabeculation and end-diastolic volume associated with Type-2 diabetes. Conclusions These data provide new insights into the mechanisms that regulate structural complexity in the heart. Changes in trabeculation may occur early in the pathogenesis of heart disease, can be modified by genes regulating pathways outside the sarcomere, and causality depends on the underlying cardiomyopathic substrate. Trabeculation progresses with cardiovascular disease, is a useful marker of remodelling, and identifies novel genetic modifiers of ventricular complexity.Figure 1

Unlocking the secrets of Cardiac development and function: the critical role of FHL2.

FHL2 (Four-and-a-half LIM domain protein 2) is a crucial factor involved in cardiac morphogenesis, the process by which the heart develops its complex structure. It is expressed in various tissues during embryonic development, including the developing heart, and has been shown to play important roles in cell proliferation, differentiation, and migration. FHL2 interacts with multiple proteins to regulate cardiac development as a coactivator or a corepressor. It is involved in cardiac specification and determination of cell fate, cardiomyocyte growth, cardiac remodeling, myofibrillogenesis, and the regulation of HERG channels. Targeting FHL2 has therapeutic implications as it could improve cardiac function, control arrhythmias, alleviate heart failure, and maintain cardiac integrity in various pathological conditions. The identification of FHL2 as a signature gene in atrial fibrillation suggests its potential as a diagnostic marker and therapeutic target for this common arrhythmia.

Identification of cell adhesion molecules for the maturation of engineered heart tissue

Abstract Background Engineered cardiac tissue (ECT) utilizing human induced pluripotent stem cell derived cardiomyocytes (hiPSC-CMs) is anticipated to function as a translational in vitro model. However, hiPSC-CMs display phenotypes indicative of immaturity, and the structural organization of ECT composed of hiPSC-CMs is insuficient when compared to that of mature adult hearts. Although the mechanisms for hiPSC-CMs maturation have been reported, little is known about the mechanisms regulating the formation of in vitro tissue such as ECT. Cell adhesion molecules play important roles in heart formation in vivo through cell-cell interactions. However, specific cell adhesion molecules responsible for tissue structure formation in in vitro tissue models, such as ECTs, have not been identified. We hypothesize that cell adhesion molecules, which regulate cell-cell attachment, are crucial for in vitro tissue formation. Purpose This study aims to identify the key cell adhesion molecules involved in cell-cell interaction and assess the effects of their expression on hiPSC-CMs and EHT functions. Methods and Results We developed a cell attachment assay to evaluate the attachment ability of hiPCS-CMs and discovered that hiPSC-CMs produced via embryoid body method (EB-hiPSC-CMs) exhibited a higher attachment ability than those produced by monolayer method (Mono-hiPSC-CMs). Further analysis revealed no significant difference in anoikis sensitivity between EB-hiPSC-CMs and Mono-hiPSC-CMs, suggesting that the observed difference in attachment ability were due to differencies in cell adhesion efficiency between hiPSC-CMs generated by two methods. Moreover, RNA-seq analysis identified nine cell adhesion molecule genes that were highly expressed in EB-hiPSC-CMs. We identified the cell adhesion molecules responsible for the attachment ability of hiPSC-CMs by knockdown and over-expression experiments. Moreover, over-expression experiments using adeno-associated virus (AAV) demonstrate that hiPSC-CMs with overexpression of a cell adhesion molecule improved calcium handling and increased propagation speed, and ECTs with overexpression of a cell adhesion molecule showed enhanced sarcomere alignment and sarcomere length compared to controls. Conclusion(s) We observed differences in attachment ability between hiPSC-CMs generated by two differentiation methods. Transcriptome analysis of these hiPSC-CMs identified key cell adhesion molecules that regulate cell-cell attachment ability of hiPSC-CMs. Furthermore, increment of attachment ability of hiPSC-CMs by overexpression of a cell adhesion molecule enhanced hiPSC-CMs and ECT functions.

SMAD3 silencing induces Epithelial-to-Mesenchymal Transition (EMT) towards cardiac pericyte progenitors with proangiogenic potential in hiPSC-derived epicardial cells

Abstract Background The epicardium is only a single mesothelial layer and "quiescent" in the adult heart. However, once the heart is injured, the epicardium reactivates and acts as a key for cardiac regeneration through epithelium-to-mesenchymal transition (EMT). While the canonical TGF-β-SMAD pathway plays a central role in regulating EMT, SMAD3 functions independent of this pathway in epicardium remain unknown. Purpose The purpose of this study is to investigate the effects of SMAD3 downregulation on EMT in epicardial cells. Methods First, we differentiated human iPSC-derived epicardial cells (EPI cells) by mimicking the process of cardiac mesoderm development. Next, siRNA targeting SMAD3 was transfected into EPI cells to silence SMAD3. We performed qRT-PCR, western blotting, immunocytochemistry, flow cytometry, transcriptional analysis, endothelial tube formation assay, and paracrine experiments using FUCCI (fluorescent ubiquitination-based cell cycle indicator) system to evaluate the phenotype of EPI cells with silenced SMAD3. Results We found that SMAD3 silencing in EPI cells resulted in loss of epicardial identity and upregulation of multiple EMT markers. Additionally, NG2 and ENG (CD105), both cardiac pericyte markers, were highly expressed in SMAD3-silenced EPI cells. RNA-sequence also revealed that SMAD3 silencing in EPI cells induced EMT facilitated towards cardiac pericyte progenitors with proangiogenic potential. In endothelial tube formation assay, SMAD3-silenced EPI cells demonstrated enhanced tube formation compared to the control (1.48-fold increase in the number of junctions, n=3; p<0.0001), which indicated their angiogenic potential. At last, we revealed the paracrine effect of SMAD3-silenced EPI cells to enhance the proliferative reactivation in iPSC-derived cardiomyocytes by showing upregulation in CDK6/CCND1 axis and FUCCI-green. Conclusion Our findings demonstrate a new role of SMAD3 biology in the human epicardium, specifically in the generation of cardiac pericyte progenitor cells that contribute to better responses in angiogenesis of the heart microvasculature enabling the possibility to continue exploiting epicardial biology for effective cardiac regeneration.

Cells of the adult mouse cardiac conduction system in wild type and Nkx2-5 heterozygous loss-of-function mutation

Abstract Background Specialised cardiomyocytes in the cardiac conduction system (CCS) generate and spread the electrical impulse that initiates synchronised heartbeats. Disrupted signal transduction in the atrioventricular (AV) node, a key electrical connection between atria and ventricles, causes AV block. AV block potentially leads to electromechanical uncoupling and sudden cardiac death. Nkx2-5 encodes a cardiac transcription factor that is critical for embryonic CCS formation. Heterozygous loss-of-function mutation of Nkx2-5 (Nkx2-5+/–) results in a hypoplastic CCS in humans and mice and progressive AV block. Purpose We aimed to create a cell atlas of the adult mouse CCS and define the consequences of Nkx2-5 haploinsufficiency on the structural organisation and transcript expression of CCS cells. Methods We performed single-nucleus RNA sequencing on the sinoatrial nodes, AV nodes, His bundles, right bundle branches (RBB) and moderator bands of 17 wild type and 14 Nkx2-5+/– mice (aged 13 to 35 weeks, 5159 CCS cells). Employing single-molecule fluorescent RNA in situ hybridisation (smFISH), we validated selected transcripts and examined the spatial organisation of identified cell populations. Results In the AV node, we identified two subpopulations of pacemaker cells that were spatially separated in the proximal and distal pacemaker region (Fig1). Within these subpopulations, expressed transcripts indicated an atrial-to-ventricular gradient of electrical activity, corresponding to their respective topography. We determined two subpopulations in the His bundle and RBB that were enriched for either slow or fast conduction markers. Spatially, the slow-conducting populations seemed to surround the fast-conducting ones and might act as electrical isolation (Fig1). In Nkx2-5+/- cells of the pacemaker AV node, His bundle, RBB and Purkinje fibres, genes involved in Slit-Robo signalling were dysregulated. Slit-Robo signalling was previously reported in neuronal differentiation and embryonic heart lumen formation. Slit ligand 3 was downregulated in Nkx2-5+/- pacemaker AV node cells (Slit3, log2FC = -2.22, p = 7.0e-42), as was the roundabout guidance receptor 1 (Robo1, log2FC = -0.96, p = 1.6e-4). By contrast, there was upregulation of neural EGF-like 1 (Nell1, log2FC = 3.18, p = 5.3e-6), an alternative ligand of roundabout guidance receptors. Altered Nell1 and Slit3 expressions were confirmed by smFISH (Fig2). Conclusions Our cell atlas defines new CCS cell populations with informative transcriptomic profiles and spatial organisation, providing insights into subpopulations in the AV junction where electrical signals switch from slow to fast conduction. We identified disrupted Slit-Robo signalling in Nkx2-5+/-, possibly impairing differentiation and maturation of the CCS and altering electrophysiologic functions. Our normative anatomical and transcription data on the CCS can inform future studies of cardiac electrophysiology and arrhythmias.Fig1 - Subpopulations in AV junctionFig2 - Nell1 smFISH in pacemaker AV node

Vitamin C supplementation improves placental function and alters placental gene expression in smokers

Maternal smoking during pregnancy (MSDP), driven by nicotine crossing the placenta, causes lifelong decreases in offspring pulmonary function and vitamin C supplementation during pregnancy prevents some of those changes. We have also shown in animal models of prenatal nicotine exposure that vitamin C supplementation during pregnancy improves placental function. In this study we examined whether vitamin C supplementation mitigates the effects of MSDP on placental structure, function, and gene expression in pregnant human smokers. Doppler ultrasound was performed in a subset of 55 pregnant smokers participating in the “Vitamin C to Decrease the Effects of Smoking in Pregnancy on Infant Lung Function” (VCSIP) randomized clinical trial (NCT01723696) and in 33 pregnant nonsmokers. Doppler ultrasound measurements showed decreased umbilical vein Doppler velocity (Vmax) in placebo-treated smokers that was significantly improved in smokers randomized to vitamin C, restoring to levels comparable to nonsmokers. RNA-sequencing demonstrated that vitamin C supplementation to pregnant smokers was associated with changes in mRNA expression in genes highly relevant to vascular and cardiac development, suggesting a potential mechanism for vitamin C supplementation in pregnant smokers to improve some aspects of offspring health.

The Role of Long Intergenic Noncoding RNA in Fetal Development.

The role of long intergenic noncoding RNAs (lincRNAs) in fetal development has emerged as a significant area of study, challenging the traditional protein-centric view of gene expression. While messenger RNAs (mRNAs) have long been recognized for their role in encoding proteins, recent advances have illuminated the critical functions of lincRNAs in various biological processes. Initially identified through high-throughput sequencing technologies, lincRNAs are transcribed from intergenic regions between protein-coding genes and exhibit unique regulatory functions. Unlike mRNAs, lincRNAs are involved in complex interactions with chromatin and chromatin-modifying complexes, influencing gene expression and chromatin structure. LincRNAs are pivotal in regulating tissue-specific development and embryogenesis. For example, they are crucial for proper cardiac, neural, and reproductive system development, with specific lincRNAs being associated with organogenesis and differentiation processes. Their roles in embryonic development include regulating transcription factors and modulating chromatin states, which are essential for maintaining developmental programs and cellular identity. Studies using RNA sequencing and genetic knockout models have highlighted the importance of lincRNAs in processes such as cell differentiation, tissue patterning, and organ development. Despite their functional significance, the comprehensive annotation and understanding of lincRNAs remain limited. Ongoing research aims to elucidate their mechanisms of action and potential applications in disease diagnostics and therapeutics. This review summarizes current knowledge on the functional roles of lincRNAs in fetal development, emphasizing their contributions to tissue-specific gene regulation and developmental processes.

Di-(2-ethylhexyl) Phthalate Exposure Induces Developmental Toxicity in the Mouse Fetal Heart via Mitochondrial Dysfunction.

Congenital heart disease (CHD) is a major cause of infant mortality and morbidity, with growing interest in the role of environmental factors in its etiology. Di-(2-ethylhexyl) phthalate (DEHP), an environmental endocrine disruptor, has been implicated in the development of CHD. This study aimed to investigate the effects of DEHP exposure on fetal heart development in mice. Pregnant mice exposed to DEHP exhibited increased fetal malformations, decreased fetal weight, and reduced crown-rump length.f Transcriptomic analysis revealed the downregulation of genes involved in aerobic respiration and mitochondrial ATP synthesis. Functional assays demonstrated reduced mitochondrial respiration, decreased ATP production, elevated reactive oxygen species levels, and lowered mitochondrial membrane potential in DEHP-exposed fetal cardiomyocytes. These findings underscore the detrimental effects of DEHP on fetal cardiac health and provide insights into the molecular mechanisms underlying DEHP-induced CHD. Understanding these mechanisms is crucial for developing preventive strategies against environmental toxicants that affect fetal cardiac development.

Developmental Toxicity and Teratogenic Effects of Dicarboximide Fungicide Iprodione on Zebrafish (Danio rerio) Embryos

Iprodione (IDN) is a broad-spectrum fungicide used to treat various fungal infections in plants. Despite its extensive use, assessment of its toxicity in aquatic organisms remains incomplete. This study investigated the deleterious effects of IDN using zebrafish (ZF) as a model organism. ZF embryos, beginning at 2 h post-fertilization (hpf), were exposed to IDN (3.75–40 mg/L), and both mortality and deformities were assessed. The impact of IDN on mortality was concentration-dependent and significant from 14 mg/L. Importantly, IDN induced several deformities at sublethal concentrations, including abnormal somites, reduced retinal pigment accumulation, yolk sac edema, hatching failure, abnormal swim bladders, and spinal curvature. The EC50 values for IDN-induced deformities were 3.44 ± 0.74 to 21.42 ± 6.00 mg/L. The calculated teratogenic index values for all deformities were above 1, indicating that IDN is teratogenic to ZF. IDN-exposed ZF also displayed abnormalities in touch-evoked escape responses. IDN significantly affected heart rate and blood flow, and induced pericardial edema and hyperemia in a concentration-dependent manner, suggesting its influence on cardiac development and the function of ZF. In conclusion, these results suggest that IDN exerts toxic effects on ZF embryos, affecting mortality, development, and behavior.

Modeling the contribution of cardiac fibroblasts in dilated cardiomyopathy using induced pluripotent stem cells (iPSCs).

Fibrosis is implicated in nearly all forms of cardiomyopathy and significantly influences disease severity and outcomes. The primary cell responsible for fibrosis is the cardiac fibroblast, which remains understudied relative to cardiomyocytes in the context of cardiomyopathy. The development of induced pluripotent stem cell-derived cardiac fibroblasts (iPSC-CFs) allows for the modeling of patient-specific disease characteristics and provides a scalable source of fibroblasts. iPSC-CFs are invaluable for understanding molecular pathways that affect disease progression and outcomes. This review explores various aspects of cardiomyopathy, with a focus on dilated cardiomyopathy (DCM), that can be modeled using iPSC-CFs and their application in drug discovery, given the current lack of approved therapies for cardiac fibrosis. We examine how iPSC-CFs can be utilized to study heart development, fibroblast heterogeneity, and activation, with the ultimate goal of developing better therapies for patients with cardiomyopathies. Significance Statement Here, we explore how iPSC-CFs can be used to study the fibrotic component of DCM. Most research has focused on cardiomyocytes, despite the significant contribution of fibroblasts to disease outcomes. iPSC-CFs serve as a valuable tool to elucidate molecular pathways leading to fibrosis, and paracrine interactions with cardiomyocytes, which are not fully understood. Gaining insights into these events could aid in the development of new therapies and enable the use of patient-derived iPSC-CFs for precision medicine, ultimately improving patient outcomes.

One-shot manufacturable soft-robotic pump inspired by embryonic tubular heart.

Soft peristaltic pumps, which use soft ring actuators instead of mechanical pistons or rollers, offer advantages in transporting liquids with non-uniform solids, such as slurry, food, and sewage. Recent advances in 3D printing with flexible thermoplastic polyurethane (TPU) present the potential for single-step fabrication of these pumps, distinguished from handcrafted, multistep traditional silicone casting methods. However, because of the relatively high hardness of TPU, TPU-based soft peristaltic pumps contract insufficiently and thus cannot perform as well as silicone-based ones. Improving the performance is crucial for fully automated, one-step manufactured soft pumps to lead to industrial use. This study aims to enhance TPU-based soft pumps through bioinspired design. Specifically, it proposed a design inspired by embryonic tubular hearts, in contrast to previous studies that mimicked digestive tracts. The new design facilitated long-axis stretching of an elliptical lumen during non-concentric contractile motion, akin to embryonic tubular hearts. The design was optimized for ring actuators and pumps 3D-printed with shore hardness 85 A TPU filament. The ring actuator achieved over 99% lumen closure with the best designs. The soft pumps transported water at flow rates of up to 218 ml min-1and generated a maximum discharge pressure of 355 mm Hg, comparable to the performance of blood pumps used in continuous renal replacement therapy.

Impact of genetic factors on antioxidant rescue of maternal diabetes-associated congenital heart disease.

Congenital heart disease (CHD) affects ~1% of live births. Although genetic and environmental etiologic contributors have been identified, the majority of CHD lacks a definitive cause, suggesting the role of gene-environment interactions (GxE) in disease pathogenesis. Maternal diabetes mellitus (matDM) is among the most prevalent environmental risk factors for CHD. However, there is a substantial knowledge gap in understanding how matDM acts upon susceptible genetic backgrounds to increase disease expressivity. Previously, we reported a GxE between Notch1 haploinsufficiency and matDM leading to increased CHD penetrance. Here, we demonstrate a cell lineage specific effect of Notch1 haploinsufficiency in matDM-exposed embryos, implicating endothelial/endocardial derived tissues in the developing heart. We report impaired atrioventricular cushion morphogenesis in matDM exposed Notch1+/- animals and show a synergistic effect of NOTCH1 haploinsufficiency and oxidative stress in dysregulation of gene regulatory networks critical for endocardial cushion morphogenesis in vitro. Mitigation of matDM-associated oxidative stress via SOD1 overexpression did not rescue CHD in Notch1 haploinsufficient mice compared to wildtype littermates. Our results show the combinatorial interaction of matDM-associated oxidative stress and a genetic predisposition, Notch1 haploinsufficiency, on cardiac development, supporting a GxE model for CHD etiology and suggesting that antioxidant strategies maybe ineffective in genetically-susceptible individuals.

Embryonic and Fetal Heart Development Before 12 Weeks of Gestation.

To assess embryonic and fetal cardiac growth and development using transvaginal 2-dimensional sonography before 12 weeks of gestation. Transvaginal scans for first-trimester dating were performed for 131 normal fetuses at 8-11 + 6 weeks of gestation. The basal-apical length (BAL), transverse length (TL), cardiac circumference (ECC), embryonic cardiac area (ECA), global sphericity index (GSI), and cardio-thoracic area ratio (CTAR) were able to be obtained in 105 normal embryos and fetuses. Nomograms for several cardiac parameters including BAL, TL, ECC, ECA, GSI, and CTAR were constructed. BAL, TL, ECC, and ECA increased curvilinearly with advancing gestation (R2 = 0.97406, 0.980396, 0.978359, and 0.920705, respectively, P < .001). GSI (mean, 1.14; SD, 0.10) and CTAR (mean, 15.7%; SD, 3.3%) values were constant at 8-11 + 6 weeks of gestation. There were significant curvilinear correlations between BAL, TL, ECC, and ECA, and crown-rump length (CRL) (R2 = 0.975976, 0.983482, 0.980673, and 0.929936, respectively, P < .001). GSI and CTAR values were not changed with the increase of CRL during this period. Our results provide nomograms for several cardiac parameters which may improve the understanding of embryonic and fetal cardiac growth and development prior to 12 weeks of gestation.