δ-Catenin activates Rho GTPase, promotes lymphangiogenesis and growth of tumor metastases.

δ-Catenin, an adherens junctions protein, is not only involved in early development, cell-cell adhesion and cell motility in neuronal cells, but it also plays an important role in vascular endothelial cell motility and pathological angiogenesis. In this study, we report a new function of δ-catenin in lymphangiogenesis. Consistent with expression of δ-catenin in vascular endothelial cells, we detected expression of the gene in lymphatic endothelial cells (LECs). Ectopic expression of δ-catenin in LECs increased cell motility and lymphatic vascular network formation in vitro and lymphangiogenesis in vivo in a Matrigel plug assay. Conversely, knockdown of δ-catenin in LECs impaired lymphangiogenesis in vitro and in vivo. Biochemical analysis shows that δ-catenin regulates activation of Rho family small GTPases, key mediators in cell motility. δ-catenin activates Rac1 and Cdc42 but inhibits RhoA in LECs. Notably, blocking of Rac1 activation impaired δ-catenin mediated lymphangiogenesis in a Matrigel assay. Consistently, loss of δ-catenin in mice inhibited the growth of tumor metastases. Taken together, these findings identify a new function of δ-catenin in lymphangiogenesis and tumor growth/metastasis, likely through modulation of small Rho GTPase activation. Targeting δ-catenin may offer a new way to control tumor metastasis

Dynamic Hyaluronan drives liver endothelial cells towards angiogenesis

Abstract Background Angiogenesis, the formation of new blood vessels from pre-existing vasculature is essential in a number of physiological processes such as embryonic development, wound healing as well as pathological conditions like, tumor growth and metastasis. Hyaluronic acid (HA), a high molecular weight polysaccharide, major component of extracellular matrix is known to associate with malignant phenotypes in melanomas and various other carcinomas. Hyaluronic acid binding protein 1 (HABP1) has been previously reported to trigger enhanced cellular proliferation in human liver cancer cells upon its over-expression. In the present study, we have identified the HA mediated cellular behaviour of liver endothelial cells during angiogenesis. Methods Endothelial cells have been isolated from perfused liver of mice. Cell proliferation was studied using microwell plates with tetrazole dye. Cell migration was evaluated by measuring endothelial monolayer wound repair as well as through transwell migration assay. Alterations in proteins and mRNA expression were estimated by immunobloting and quantitative real time PCR using Applied Biosystems. The paraformaldehyde fixed endothelial cells were used for immuno- florescence staining and F-actin detection with conjugated antibodies. The images were captured by using Olympus florescence microscope (IX71). Results We observed that administration of HA enhanced cell proliferation, adhesion, tubular sprout formation as well as migration of liver endothelial cells (ECs). The effect of HA in the rearrangement of the actins confirmed HA -mediated cytoskeleton re-organization and cell migration. Further, we confirmed enhanced expression of angiogenic factors like VEGF-A and VEGFR1 in endothelial cells upon HA treatment. HA supplementation led to elevated expression of HABP1 in murine endothelial cells. It was interesting to note that, although protein levels of β- catenin remained unaltered, but translocation of this protein from membrane to nucleus was observed upon HA treatment, suggesting its role not only in vessel formation but also its involvement in angiogenesis signalling. Conclusions The elucidation of molecular mechanism (s) responsible for HA mediated regulation of endothelial cells and angiogenesis contributes not only to our understanding the mechanism of disease progression but also offer new avenues for therapeutic intervention

δ-catenin regulates Rho GTPase activity in LECs.

<p>HMVEC-LLy cells were transfected with an empty vector or δ-catenin expression vectors for 48 hours. Cell lysate was collected and analyzed for activation of Rac1 (Panel A), Cdc42 (Panel B), and RhoA (Panel C). Activation of Rac1 and Cdc42 was determined by using a PAK1- pull-down assay while active RhoA was pulled down with Rhotekin-agarose beads. For knockdown experiments, HMVEC-LLy cells were transfected with shRNA for δ-catenin or control shRNA constructs for 48 hours. Cell lysate was collected and analyzed for activation of Rac1 (Panel D), Cdc42 (Panel E), and RhoA (Panel F) by Western blotting. HMVEC-LLy cells transfected with a vector control or δ-catenin expression vector plus a vector control or Rac1N17 were incubated on Matrigel for 24 hours. The number of vascular branch points was counted in 10 randomly selected fields under microscopy (Panel G). All experiments were repeated three times. Mean and SE were plotted. * p<0.05. </p

Loss of δ-catenin impairs lymphangiogenesis and tumor growth in an experimental metastasis mouse model.

<p>3LL cells (1x10⁵) were injected into tail vein of wild type littermates and δ-catenin null mice. Two weeks after the injection, lungs were excised from mice and images were taken (Panel A). Arrows point to tumor metastases in lungs. Lung weight (Panel B) and lung surface metastases (Panel C) were quantified and graphed. *p<0.05. Tumor metastases were sectioned and stained with an antibody against Lyve-1 (Panel D). Lyve-1 positive vascular structures were counted in 10 randomly selected high power fields under microscopy and graphed (Panel E). *p<0.05. Representative images were shown. This experiment was repeated twice and each time 5 mice per group were used. </p

Controlled transient respiratory arrest along with rapid right ventricular pacing for improving balloon stability during balloon valvuloplasty in pediatric patients with congenital aortic stenosis - A retrospective case series analysis

Rapid right ventricular pacing is safe, effective, and established method to provide balloon stability during balloon aortic valvuloplasty (BAV). Controlled transient respiratory arrest at this point of time may further reduce left ventricular stroke volume, providing an additional benefit to maintain balloon stability. Two groups were studied. Among the 10 patients, five had rapid pacing alone (Group A), while the other five were provided with cessation of positive pressure breathing as well (Group B). The outcomes of BAV in the two groups of patients were studied. One patient in Group A had failed balloon dilatation even after the fourth attempt, while in Group B there were no failures. The peak systolic gradient reduction was higher in Group B (70.05&#x0025; in comparison to 52.16&#x0025; of group A). In Group A, five subjects developed aortic regurgitation (grade 2 in four and grade 3 in one, while no grade 3 aortic regurgitation developed in any patient in Group B). Controlled transient respiratory arrest along with rapid ventricular pacing may be effective in maintaining balloon stability and improve the outcome of BAV

Survivin inhibition ameliorates liver fibrosis by inducing hepatic stellate cell senescence and depleting hepatic macrophage population.

Persistent activation of hepatic stellate cells (HSCs) in the injured liver leads to the progression of liver injury from fibrosis to detrimental cirrhosis. In a previous study, we have shown that survivin protein is upregulated during the early activation of HSCs, which triggers the onset of liver fibrosis. However, the therapeutic potential of targeting survivin in a fully established fibrotic liver needs to be investigated. In this study, we chemically induced hepatic fibrosis in mice using carbon tetrachloride (CCl4) for 6&nbsp;weeks, which was followed by treatment with a survivin suppressant (YM155). We also evaluated survivin expression in fibrotic human liver tissues, primary HSCs, and HSC cell line by histological analysis. αSMA+ HSCs in human and mice fibrotic liver tissues showed enhanced survivin expression, whereas the hepatocytes and quiescent (qHSCs) displayed minimal expression. Alternatively, activated M2 macrophage subtype induced survivin expression in HSCs through the TGF-β-TGF-β receptor-I/II signaling. Inhibition of survivin in HSCs promoted cell cycle arrest and senescence, which eventually suppressed their activation. In vivo, YM155 treatment increased the expression of cell senescence makers in HSCs around fibrotic septa such as p53, p21, and β-galactosidase. YM155 treatment in vivo also reduced the hepatic macrophage population and inflammatory cytokine expression in the liver. In conclusion, downregulation of survivin in the fibrotic liver decreases HSC activation by inducing cellular senescence and modulating macrophage cytokine expression that collectively ameliorates liver fibrosis

Additional file 1: of Dynamic Hyaluronan drives liver endothelial cells towards angiogenesis

Table S1. Sequences of primers used for quantitative real time PCR on mice. (DOCX 25 kb

Management of Postoperative Hypoxaemia in Patients Following Upper Abdominal Laparoscopic Surgery. - A Comparative Study

Noninvasive ventilation has been shown to reduce acute postoperative hypoxaemia, with significant reduction in the incidence of re-intubation, complications and a trend towards lower mortality. The aim of the study was to determine the effectiveness of CPAP vs venturi therapy in early achievement of oxygenation goals and in prevention of re-intubation for management of postoperative hypoxaemia following laparoscopic cholecystectomy. Forty adult patients of ASA physical status I& II, scheduled for elective laparoscopic cholecystectomy, those were unable to maintain SpO2 > 95% breathing room air after extubation, were recruited for a prospective, randomized comparative study. Patients with PaO2 / FiO2 between 250 and 300 were included in the study and were randomly allocated to one of the two groups to receive oxygen therapy either using a CPAP of 10 cm of water and a FiO2 of 0.5 (Group A) or using a venturi mask of FiO2 of 0.5 (Group B) . All patients were observed postoperatively upto 18 h and were screened by ABG analyses at 6, 12 and 18 h of treatment. SpO2, ECG, heart rate, respiratory rate, temperature and NIBP were monitored throughout the study period. Patients in Group A showed significant improvement in early achievement of adequate oxygenation than those in Group B, although, due to intolerance to CPAP therapy two patients in Group A needed reintubation to maintain adequate oxygenation. To conclude, oxygenation using continuous positive airway pressure is a safe and effective means in improving gas exchange to treat acute postoperative hypoxaemia in conscious and cooperative patients