PTEN is involved in modulation of vasculogenesis in early chick embryos

Baicalin administration attenuates hyperglycemia-induced malformation of cardiovascular system

In this study, the effects of Baicalin on the hyperglycemia-induced cardiovascular malformation during embryo development were investigated. Using early chick embryos, an optimal concentration of Baicalin (6 μM) was identified which could prevent hyperglycemia-induced cardiovascular malformation of embryos. Hyperglycemia-enhanced cell apoptosis was reduced in embryos and HUVECs in the presence of Baicalin. Hyperglycemia-induced excessive ROS production was inhibited when Baicalin was administered. Analyses of SOD, GSH-Px, MQAE and GABAA suggested Baicalin plays an antioxidant role in chick embryos possibly through suppression of outwardly rectifying Cl(−) in the high-glucose microenvironment. In addition, hyperglycemia-enhanced autophagy fell in the presence of Baicalin, through affecting the ubiquitin of p62 and accelerating autophagy flux. Both Baicalin and Vitamin C could decrease apoptosis, but CQ did not, suggesting autophagy to be a protective function on the cell survival. In mice, Baicalin reduced the elevated blood glucose level caused by streptozotocin (STZ). Taken together, these data suggest that hyperglycemia-induced embryonic cardiovascular malformation can be attenuated by Baicalin administration through suppressing the excessive production of ROS and autophagy. Baicalin could be a potential candidate drug for women suffering from gestational diabetes mellitus.

A longitudinally extensive myelopathy associated with multiple spinal arteriovenous fistulas in a patient with Cowden syndrome: a case report

BACKGROUND CONTEXT

Cowden syndrome is an autosomal dominant syndrome characterized by multiple hamartomas and an increased cancer risk. It is associated with mutations in the phosphatase and tensin homologue (PTEN) gene that encodes a tumor suppressant phosphatase.

PURPOSE

The study aimed to report an unusual case of multiple spinal epidural arteriovenous fistulas in a patient diagnosed with Cowden syndrome.

STUDY DESIGN

This is a case report.

PATIENT SAMPLE

The patient is a 57-year-old woman.

METHODS

We report the case of a 57-year-old woman with a history of multiple cancers, with acute exacerbation of lower extremity weakness and numbness that had progressed over a month.

RESULTS

Magnetic resonance imaging showed abnormal signal in the thoracolumbar spinal cord, with enhancement after contrast administration. A spinal angiogram confirmed the presence of multiple spinal epidural arteriovenous fistulas. Genetic testing confirmed the diagnosis of Cowden syndrome with a mutation in intron 3 of the PTEN gene.

CONCLUSIONS

Spinal vascular malformations occur in patients with Cowden syndrome, and they can be multifocal and locally aggressive. It is important to raise the suspicion of Cowden syndrome in patients with spinal cord vascular anomalies and a history of multiple cancers, as the correct genetic diagnosis may have implications for management and cancer screening.

MicroRNA-19b Mediates Lung Epithelial-Mesenchymal Transition via Phosphatidylinositol-3,4,5-Trisphosphate 3-Phosphatase in Response to Mechanical Stretch

Lung epithelial-mesenchymal transition (EMT) plays an important role in ventilation-associated lung fibrosis, which may contribute to the poor outcome of patients with acute respiratory distress syndrome. Because microRNAs control and modulate normal physiological and pathophysiological processes, we investigated the role of microRNAs in the development of acute respiratory distress syndrome-associated EMT in response to mechanical stress. In the current study, primary human alveolar epithelial type II (AEII) cells were subjected to cyclic stretch that resulted in EMT profiles with decreased gene expression of cytokeratin-8, E-cadherin, and surfactant protein B, and increased expression of vimentin, α-smooth muscle actin, and N-cadherin. Microarray analysis revealed that the expression of microRNA-19b (miR-19b) was up-regulated in the AEII cells, and real-time polymerase chain reaction showed that the expression of miR-19b increased in both the AEII cells and the primary human small-airway epithelial cells. Overexpression of miR-19b in small-airway epithelial cells promoted the mechanical stretch-induced EMT phenotypes, whereas inhibition of miR-19b attenuated it. The inhibitory effect of miR-19b was attributed to enhanced signaling of phosphatidylinositol-3,4,5-trisphosphate 3-phosphatase (PTEN), leading to inactivation of the AKT pathway. Restoration of PTEN expression or inhibition of AKT phosphorylation suppressed the mechanical stretch-induced EMT phenotypes. We further demonstrated that the mechanical stretch-induced miR19 expression was regulated by the focal adhesion kinase-Rho pathway. In conclusion, we found that miR-19b plays a key role in the development of the EMT phenotype through down-regulation of PTEN in human lung epithelial cells in response to mechanical stretch. The miR-19b-PTEN signaling pathway may serve as a novel therapeutic target in the context of ventilator-associated lung fibrosis.

Excess Imidacloprid Exposure Causes the Heart Tube Malformation of Chick Embryos

As a neonicotinoid pesticide, imidacloprid is widely used to control sucking insects on agricultural planting and fleas on domestic animals. However, the extent to which imidacloprid exposure has an influence on cardiogensis in early embryogenesis is still poorly understood. In vertebrates, the heart is the first organ to be formed. In this study, to address whether imidacloprid exposure affects early heart development, the early chick embryo has been used as an experimental model because of its accessibility at its early developmental stage. The results demonstrate that exposure of the early chick embryo to imidacloprid caused malformation of heart tube. Furthermore, the data reveal that down-regulation of GATA4, NKX2.5, and BMP4 and up-regulation of Wnt3a led to aberrant cardiomyocyte differentiation. In addition, imidacloprid exposure interfered with basement membrane breakdown, E-cadherin/laminin expression, and mesoderm formation during the epithelial-mesenchymal transition (EMT) in gastrula chick embryos. Finally, the DiI-labeled cell migration trajectory indicated that imidacloprid restricted the cell migration of cardiac progenitors to primary heart field in gastrula chick embryos. A similar observation was also obtained from the cell migration assay of scratch wounds in vitro. Additionally, imidacloprid exposure negatively affected the cytoskeleton structure and expression of corresponding adhesion molecules. Taken together, these results reveal that the improper EMT, cardiac progenitor migration, and differentiation are responsible for imidacloprid exposure-induced malformation of heart tube during chick embryo development.

Autophagy is involved in high glucose-induced heart tube malformation

Both pre-gestational and gestational diabetes have an adverse impact on heart development, but little is known about the influence on the early stage of heart tube formation. Using early gastrulating chick embryos, we investigated the influence of high glucose on the process of heart tube formation, specifically during the primary heart field phase. We demonstrated that high-glucose exposure resulted in 3 types of heart tube malformation: 1) ventricular hypertrophy, 2) ventricular hypertrophy with dextrocardia and 3) ventricular hypertrophy and dextrocardia with the fusion anomaly of a bilateral primary heart tube. Next, we found that these malformation phenotypes of heart tubes might mainly originate from the migratory anomaly of gastrulating precardiac mesoderm cells rather than cell proliferation in the developmental process of bilateral primary heart field primordia. The treatment of rapamycin (RAPA), an autophagy inducer, led to a similar heart tube malformation phenotype as high glucose. Additionally, high-glucose exposure promoted the expression of the key autophagy protein LC3B in early chick tissue. Atg7 is strongly expressed in the fusion site of bilateral primary heart tubes. All of these data imply that autophagy could be involved in the process of high-glucose-induced malformation of the heart tube.

Effects of 2,5-hexanedione on angiogenesis and vasculogenesis in chick embryos

n-Hexane is widely used in industry and its metabolite, 2,5-hexanedione (2,5-HD), has been implicated as a neural toxin in the developing fetus. Using the chick embryo model, we have previously revealed the neurotoxicity of 2,5-HD during development and established that high dose of 2,5-HD was embryo lethal. In view of the close linkage in biology for neurogenesis and angiogenesis, we speculated that it was most likely caused by cardiovascular dysplasia, therefore in this study, we investigated the effects of 2,5-HD on the development of the vasculature, which involves vasculogenesis and angiogenesis. Using gastrulating chick embryos as a model, we demonstrated that the hemangioblasts (precursor of hematopoietic and endothelial cells) migrated to the area opaca where they form the blood islands. However, this process was impaired when the embryos were treated with 2,5-HD, suggesting that 2,5-HD is capable of impairing vasculogenesis. To study the effect of 2,5-HD exposure on angiogenesis, we used the chick yolk-sac membrane (YSM) and chorioallantoic membrane (CAM) models. We found that, at low (0.02M) concentration, 2,5-HD stimulated angiogenesis while at higher concentrations (>0.1M) it inhibited this process. This biphasic response of angiogenesis to 2,5-HD exposure was found to be associated with altered expression of the VEGF-R, FGF-2 and angiogenin. Moreover, we also determined that 2,5-HD exposure increased the reactive oxygen species (ROS) production. In conclusion, 2,5-HD could induce dysplasia in the developing vasculature, which in turn could cause extravascular hemolysis and the embryos to die.