Mechanical stimulus is critical to cardiovascular development during embryogenesis period.The mechanoreceptors of endocardial cells and cardiac myocytes may sense mechanical signals and initiate signal transduction that induce gene expression at a cellular level,and then translate molecular-level events into tissue-level deformations,thus guiding embryo development.This review summarizes the regulatory roles of mechanical signals in the early cardiac development including the formation of heart tube,looping,valve and septal morphogenesis,ventricular development and maturation.Further,we discuss the potential mechanical transduction mechanisms of platelet endothelial cell adhesion molecule 1-vascular endothelial-cadherin-vascular endothelial growth factor receptor 2 complex,primary cilia,ion channels,and other mechanical sensors that affect some cardiac malformations.
Animals ; Heart/embryology* ; Humans ; Mechanotransduction, Cellular ; Myocytes, Cardiac/physiology* ; Vascular Endothelial Growth Factor A/metabolism*

Animals ; Brain ; embryology ; Ear ; embryology ; Esophagus ; embryology ; Fallopian Tubes ; embryology ; Female ; Heart ; embryology ; Humans ; Kidney ; embryology ; Liver ; embryology ; Lung ; embryology ; Male ; Organogenesis ; physiology ; Penis ; embryology ; Rabbits ; Stomach ; embryology ; Vagina ; embryology

OBJECTIVE: To investigate the molecular mechanism of trichloroethylene (TCE) cardiac developmental toxicity on zebrafish embryos and to try to provide experimental data for related intervention. METHODS: Zebrafish embryos were purchased from the National Zebrafish Resource Center. The embryos were divided into DMSO(control group), DMSO+CHIR, DMSO+XAV, TCE, TCE+CHIR and TCE+XAV groups(TCE at the concentration of 1, 10 and 100 ppb, with the DMSO as control; DMSO: Dimethyl suldoxide; CHIR: CHIR-99021, Wnt agonist; XAV: XAV-939, Wnt antagonist), 60 embryos per group. Zebrafish embryos were fed in systematic aquaculture water, 28℃. The water was replaced every 24 h and drugs were added according to the grouping scheme. The cardiac tissues were dissected and analyzed by transcriptome microarray after RNA extraction. The expressions of Wnt signaling pathway related genes were verified by q-PCR. Wnt atagonist XAV and activator CHIR were used alone or in combination to further evaluate the possibility of the Wnt signaling participating in the cardiac developmental toxicity induced by TCE. RESULTS: Compared with control, Zebra fish embryos exposed to TCE showed a significant increase in heart defects, and the main phenotypes were abnormal atrioventricular ratio, looping defects and pericardial edema. The results of microarray profiling showed that the expressions of genes related to Wnt signaling pathway were affected significantly. The results of qPCR further confirmed that TCE inhibited the expressions of Wnt pathway target genes Axin2, Sox9b and Nkx2.5(P＜0.05). Wnt agonist CHIR reduced the TCE-induced cardiac malformation rate significantly, while the addition of Wnt antagonist XAV markedly enhanced the cardiac developmental toxicity of TCE. CONCLUSION Exposure to TCE leads to heart malformation in zebrafish embryos. Wnt signaling pathway may be involved in the cardiac developmental toxicity induced by TCE.
Animals ; Gene Expression Regulation, Developmental ; drug effects ; Heart ; drug effects ; embryology ; Transcriptome ; Trichloroethylene ; adverse effects ; Wnt Signaling Pathway ; drug effects ; Zebrafish

Background: Valproic acid (VPA) exposure during pregnancy has been proven to contribute to congenital heart disease (CHD). Our previous findings implied that disruption of planar cell polarity (PCP) signaling pathway in cardiomyocytes might be a factor for the cardiac teratogenesis of VPA. In addition, the teratogenic ability of VPA is positively correlated to its histone deacetylase (HDAC) inhibition activity. This study aimed to investigate the effect of the VPA on cardiac morphogenesis, HDAC1/2/3, and PCP key genes (Vangl2/Scrib/Rac1), subsequently screening out the specific HDACs regulating PCP pathway. Methods: VPA was administered to pregnant C57BL mice at 700 mg/kg intraperitoneally on embryonic day 10.5. Dams were sacrificed on E15.5, and death/absorption rates of embryos were evaluated. Embryonic hearts were observed by hematoxylin-eosin staining to identify cardiac abnormalities. H9C2 cells (undifferentiated rat cardiomyoblasts) were transfected with Hdac1/2/3 specific small interfering RNA (siRNA). Based on the results of siRNA transfection, cells were transfected with Hdac3 expression plasmid and subsequently mock-treated or treated with 8.0 mmol/L VPA. Hdac1/2/3 as well as Vangl2/Scrib/Rac1 mRNA and protein levels were determined by real-time quantitative polymerase chain reaction and Western blotting, respectively. Total HDAC activity was detected by colorimetric assay. Results: VPA could induce CHD (P < 0.001) and inhibit mRNA or protein expression of Hdac1/2/3 as well as Vangl2/Scrib in fetal hearts, in association with total Hdac activity repression (all P < 0.05). In vitro, Hdac3 inhibition could significantly decrease Vangl2/Scrib expression (P < 0.01), while knockdown of Hdac1/2 had no influence (P > 0.05); VPA exposure dramatically decreased the expression of Vanlg2/Scrib together with Hdac activity (P < 0.01), while overexpression of Hdac3 could rescue the VPA-induced inhibition (P > 0.05). Conclusion VPA could inhibit Hdac1/2/3, Vangl2/Scrib, or total Hdac activity both in vitro and in vivo and Hdac3 might participate in the process of VPA-induced cardiac developmental anomalies.
Animals ; Cell Polarity ; Enzyme Inhibitors ; adverse effects ; Female ; Fetal Heart ; embryology ; Heart Defects, Congenital ; chemically induced ; physiopathology ; Histone Deacetylase Inhibitors ; Histone Deacetylases ; drug effects ; physiology ; Mice ; Mice, Inbred C57BL ; Nerve Tissue Proteins ; Pregnancy ; Rats ; Transfection ; Valproic Acid ; adverse effects

Cardiac valves are highly organized yet delicate structures that ensure unidirectional blood flow through the cardiac chambers and large vessels. Disturbed development of cardiac valves can lead to aberrant heart formation and function which account for approximately one third of congenital heart diseases. The formation of cardiac valves is a dynamic process accomplished by a series of complex events including lineage determination and cell proliferation, differentiation and migration. This paper reviews current knowledge about the role of Tbx20 gene in the development of cardiac valves, which include functional diversities of Tbx20 at various stages of cardiac valve development, its interaction with other signaling pathways, and genetic network involved in endocardial development.
Cell Differentiation ; Cell Proliferation ; Gene Expression Regulation, Developmental ; Gene Regulatory Networks ; Heart Valves ; embryology ; Humans ; T-Box Domain Proteins ; genetics

BackgroundOutflow tract (OFT) septation defects are a common cause of congenital heart disease. Numerous studies have focused on the septation mechanism of the OFT, but have reported inconsistent conclusions. This study, therefore, aimed to investigate the septation of the aortic sac and the OFT in the early embryonic human heart.

MethodsSerial sections of 27 human embryonic hearts from Carnegie stage (CS) 10 to CS19 were immunohistochemically stained with antibodies against α-smooth muscle actin (α-SMA) and myosin heavy chain.

ResultsAt CS10-CS11, the OFT wall was an exclusively myocardial structure that was continuous with the aortic sac at the margin of the pericardial cavity. From CS13 onward, the OFT was divided into nonmyocardial and myocardial portions. The cushion formed gradually, and its distal border with the OFT myocardium was consistently maintained. The aortic sac between the fourth and sixth aortic arch arteries was degenerated. At CS16, the α-SMA-positive aortopulmonary septum formed and fused with the two OFT cushions, thus septating the nonmyocardial portion of the OFT into two arteries. At this stage, the cushions were not fused. At CS19, the bilateral cushions were fused to septate the myocardial portion of the OFT.

ConclusionsData suggest that the OFT cushion is formed before the aortopulmonary septum is formed. Thus, the OFT cushion is not derived from the aortopulmonary septum. In addition, the nonmyocardial part of the OFT is septated into the aorta and pulmonary trunk by the aortopulmonary septum, while the main part of the cushion fuses and septates the myocardial portion of the OFT.

Actins ; metabolism ; Alkaline Phosphatase ; metabolism ; Aorta ; embryology ; Heart ; embryology ; Heart Valves ; embryology ; Humans ; Immunohistochemistry ; Myosin Heavy Chains ; metabolism

Formation of the heart valves is one of critical steps in vertebrate cardiac development. Valvular heart anomaly can induce severe cardiac impairment, which is one of most common symptoms for congenital heart defects (CHD). The canonical Wnt/β-catenin signaling pathway, which is essential for numerous developmental processes, has also been suggested to be involved in the regulation of proliferation, differentiation, and migration of myocardium, endocardium and valve primordia at different stages. The canonical Wnt signaling also regulates the endocardial-mesenchymal transformation (EMT) process during the endocardial cushion formation. This paper reviews current knowledge about the canonical Wnt signaling pathway in heart valve development, including the functional diversities of Wnt activity in heart valve development at different stages and its interaction with other valve-relevant signaling pathways and the potential role of canonical Wnt activity in heart valve mesenchymal stem cells at the late developmental stage.
Cell Differentiation ; Cell Proliferation ; Epithelial-Mesenchymal Transition ; Heart Valves ; embryology ; Humans ; Wnt Signaling Pathway ; physiology

OBJECTIVETo explore the effects of trichloroethylene (TCE) on cardiac developmental differentiation in human embryonic stem cells.

METHODSIn this study, based on the human embryonic stem cells in vitro cardiac differentiation assay, we investigated the potential effect of TCE exposure on the cardiac toxicity in embryo development. Human embryonic stem cells were treated with TCE at different concentrations of 100 ppb, 1 ppm, and 10 ppm and dimethyl sulfoxide(DMSO) treated as control. The MTT assay was performed to examine the cytoplasmic toxicity of TCE exposure. The beating percentages were recorded and the expression of cardiac specific gene was evaluated by PCR or flow cytometry. Also, real time PCR was performed to verify the micro array analysis on the expression level changes of genes which were involved in the Ca2+ signal pathways.

RESULTSCompared with the control group, there was no significant difference in cell viability when cells were treated with TCE at the concentrations of 100 ppb, 1 ppm, and 10 ppm. However, TCE could inhibit the expression of cTnT protein in a concentration-dependant manner. And the most interestingly, TCE significantly inhibited the cardiac differentiation characterized by the decrease beating percentages. Genes involved in Ca2+ signaling pathway were severely disrupted by TCE.

CONCLUSIONTCE inhibited the cardiac specific differentiation of human embryonic stem cell and at the meanwhile the genes responsible for Ca2+ signaling pathway were severely disrupted, which could contribute the severe effects of TCE cardiotoxicity.

Calcium Signaling ; Cell Differentiation ; Cells, Cultured ; Embryonic Development ; Embryonic Stem Cells ; cytology ; drug effects ; Heart ; embryology ; Humans ; Trichloroethylene ; toxicity

Right aortic arch with isolation of the left subclavian artery is a rare anomaly. The incidence of bilateral ductus arteriosus is sporadic, and a right aortic arch with isolation of the left subclavian artery in association with bilateral ductus arteriosus is therefore extremely rare. Since the symptoms and signs of isolation of the left subclavian artery can include the absence or underdevelopment of the left arm, subclavian steal syndrome, or pulmonary artery steal syndrome, the proper therapeutic approach is controversial. We report a case in which surgical reconstruction was used to treat isolation of the left subclavian artery with right aortic arch in association with bilateral ductus arteriosus and a ventricular septal defect.
Aorta, Thoracic* ; Arm ; Ductus Arteriosus* ; Embryology ; Heart Defects, Congenital ; Heart Septal Defects, Ventricular* ; Incidence ; Pulmonary Artery ; Subclavian Artery* ; Subclavian Steal Syndrome

OBJECTIVETo observe the temporal modification of transcription factor Mef2c by histone acetylases (HATs) P300, PCAF, and SRC1 during cardiogenesis and to provide a basis for investigating the pathogenesis of congenital heart disease.

METHODSThe normal heart tissues from embryonic mice (embryonic days 14.5 and 16.5) and neonatal mice (postnatal days 0.5 and 7) were collected. The binding of P300, PCAF, and SRC1 to Mef2c gene and level of histone H3 acetylation in the promoter region of Mef2c were evaluated by chromatin immunoprecipitation assays. Meanwhile, real-time PCR was used to measure the mRNA expression of Mef2c.

RESULTSP300, PCAF, SRC1 were involved in histone acetylation in the promoter region of Mef2c during cardiogenesis in mice, and binding of P300, PCAF, and SRC1 to the promoter of Mef2c varied significantly in different stages of cardiogenesis (P<0.01). The level of histone H3 acetylation and mRNA expression of Mef2c in the promoter region of Mef2c also varied significantly in different stages of cardiac development (P<0.01). The levels of acetylated H3, Mef2c mRNA, and HATs (P300, PCAF, SRC1) changed over time. They were highest on embryonic day 14.5 (P<0.01), decreased gradually with cardiac development, and were maintained at low levels after birth.

CONCLUSIONSThe mRNA expression of Mef2c varies during cardiogenesis in mice, which indicates that Mef2c plays an important role in the process of cardiac development. Meanwhile, histone acetylation in the promoter region of Mef2c is regulated temporally by HATs P300, PCAF, and SRC1.

Animals ; Female ; Gene Expression Regulation, Developmental ; Heart ; embryology ; Histone Acetyltransferases ; physiology ; MEF2 Transcription Factors ; genetics ; physiology ; Male ; Mice ; Promoter Regions, Genetic ; RNA, Messenger ; analysis