PEG-PLA nanoparticles facilitate siRNA knockdown in adult zebrafish heart.

The remarkable regenerative capacity of the zebrafish has made it an important model organism for studying heart regeneration. However, current loss-of-function studies are limited by a lack of conditional-knockout and effective gene-knockdown methods for the adult heart. Here, we report a novel siRNA knockdown method facilitated by poly(ethylene glycol)-b-poly(D,L-lactide) (PEG-PLA) nanoparticles. The siRNA-encapsulated nanoparticles successfully entered cells and resulted in remarkable gene-specific knockdown in the adult heart. This effect was demonstrated by down-regulation of the Aldh1a2 and Dusp6 proteins after intrapleural delivery of nanoparticle-encapsulated siRNAs. Furthermore, siRNA-mediated knockdown of Aldh1a2 was sufficient to inhibit myocardial proliferation and decrease the numbers of Gata4-positive cardiomyocytes after ventricular resection. Therefore, the results of this work demonstrate that nanoparticle-facilitated siRNA delivery provides an alternative tool for loss-of-function studies of genes in the adult heart in particular and other organs in general in the adult zebrafish.

Genetic interaction between pku300 and fbn2b controls endocardial cell proliferation and valve development in zebrafish.

Abnormal cardiac valve morphogenesis is a common cause of human congenital heart disease. The molecular mechanisms regulating endocardial cell proliferation and differentiation into cardiac valves remain largely unknown, although great progress has been made on the endocardial contribution to the atrioventricular cushion and valve formation. We found that scotch tape(te382) (sco(te382)) encodes a novel transmembrane protein that is crucial for endocardial cell proliferation and heart valve development. The zebrafish sco(te382) mutant showed diminished endocardial cell proliferation, lack of heart valve leaflets and abnormal common cardinal and caudal veins. Positional cloning revealed a C946T nonsense mutation of a novel gene pku300 in the sco(te382) locus, which encoded a 540-amino-acid protein on cell membranes with one putative transmembrane domain and three IgG domains. A known G3935T missense mutation of fbn2b was also found ∼570 kb away from pku300 in sco(te382) mutants. The genetic mutant sco(pku300), derived from sco(te382), only had the C946T mutation of pku300 and showed reduced numbers of atrial endocardial cells and an abnormal common cardinal vein. Morpholino knockdown of fbn2b led to fewer atrial endocardial cells and an abnormal caudal vein. Knockdown of both pku300 and fbn2b phenocopied these phenotypes in sco(te382) genetic mutants. pku300 transgenic expression in endocardial and endothelial cells, but not myocardial cells, partially rescued the atrial endocardial defects in sco(te382) mutants. Mechanistically, pku300 and fbn2b were required for endocardial cell proliferation, endocardial Notch signaling and the proper formation of endocardial cell adhesion and tight junctions, all of which are crucial for cardiac valve development. We conclude that pku300 and fbn2b represent the few genes capable of regulating endocardial cell proliferation and signaling in zebrafish cardiac valve development.

N-methyl-2-pyrrolidonium methyl sulfonate acidic ionic liquid as a new dynamic coating for separation of basic proteins by capillary electrophoresis.

A simple and economical CE method has been developed for the analysis of four model basic proteins by employing N-methyl-2-pyrrolidonium methyl sulfonate ionic liquid (IL) as the dynamic coating material based on the interaction of both between electrostatic attraction and hydrogen bond, and between the organic cations of IL and the inner surface of bare fused-silica capillary. The N-methyl-2-pyrrolidonium-based IL modified capillary not only generated a stable suppressed electroosmotic flow, but also effectively eliminated the wall adsorption of proteins. Several important parameters such as the IL concentration, pH values, and concentrations of the background electrolyte were optimized to improve the separation of basic proteins. Consequently, under the optimum separation conditions, a satisfied separation of basic proteins including lysozyme, cytochrome c, ribonuclease A, and α-chymotrypsinogen A with theoretical plates ranging from 2.09 × 10(5) to 4.48 × 10(5) plates/m had been accomplished within 15 min. The proposed method first illustrated the effect of hydrogen bond between coating material and inner capillary surface on the coating, which should be a new strategy to design and select more effective coating materials to form more stable coatings in CE.

Down-regulated miR-148b increases resistance to CHOP in diffuse large B-cell lymphoma cells by rescuing Ezrin.

BACKGROUND: Aberrant microRNA (miRNAs) have recently been proposed as important regulators in acquiring resistance to cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) in diffuse large B-cell lymphoma (DLBCL). The purpose of this study was to establish the role of miR-148b in the development of CHOP resistance in DLBCL. METHODS: The expression patterns of miR-148b, HDAC6, and Ezrin were detected in CHOP-resistant clinical specimens and a DLBCL cell line. miR-148b, HDAC6, and Ezrin in DLBCL cells were manipulated by cell transfection to explore the functional correlation between them. Cell viability was determined using a CCK-8 assay. RESULTS: We found that miR-148b levels were markedly reduced and that the protein expressions of HDAC6 and Ezrin were increased in DLBCL CHOP-resistant clinical specimens and the cell line CRL2631/CHOP. Indeed, HDAC6 decreased the acetylation of histones H3 and H4 in the miR-148b promoter to inhibit miR-148b expression in DLBCL. Moreover, down-regulated miR-148b encouraged CHOP resistance in CRL2631 cells and miR-148b sensitized CRL2631 cells. We further revealed that Ezrin was negatively regulated by miR-148b and that the knockdown of Ezrin significantly attenuated CHOP resistance in CRL2631 cells induced by miR-148b silencing. MiR-148b also sensitized CRL2631/CHOP cell xenografts to CHOP in mice. CONCLUSION: Our data indicated that the high level of HDAC6 inhibited miR-148b via maintaining the low acetylation of histones H3 and H4 in the miR-148b promoter, thus rescuing Ezrin expression and promoting CHOP resistance in DLBCL.

Vascular Endothelial Growth Factor and Cluster of Differentiation 34 for Assessment of Perioperative Bleeding Risk in Gastric Cancer Patients.

BACKGROUND: Angiogenesis is the formation of new blood vessels to supply nutrients to tumors. Vascular endothelial growth factor (VEGF) and cluster of differentiation 34 (CD34) are important signaling proteins involved in angiogenesis. Many studies have demonstrated that VEGF and CD34 are related to tumor progression. This study focused on the relationship between VEGF, CD34, and perioperative hemorrhage in patients with gastric cancer. METHODS: To observe the relationship between VEGF and CD34, we tracked 112 patients with advanced gastric cancer for 5 years to assess factors related to hemorrhage, using immunohistochemistry. The results were subjected to statistical analysis using a 2 × 2 contingency table, logistic regression, and receiver operating characteristic (ROC) test. RESULTS: The concentrations of VEGF and CD34 were critically correlated with perioperative hemorrhage and neural invasion in patients with gastric cancer (P < 0.05). Expression of VEGF and CD34 was related (P < 0.05, χ2 = 6.834). VEGF and CD34 co-expression strongly increased the risk of preoperative bleeding (area under the ROC curve >0.7, P < 0.05). CONCLUSIONS: Expression of VEGF and CD34 was critically correlated with perioperative hemorrhage in gastric cancer patients. Co-expression of VEGF and CD34 could be an effective indicator for evaluating the risk of perioperative bleeding in gastric cancer patients.

Hydrogen peroxide primes heart regeneration with a derepression mechanism.

While the adult human heart has very limited regenerative potential, the adult zebrafish heart can fully regenerate after 20% ventricular resection. Although previous reports suggest that developmental signaling pathways such as FGF and PDGF are reused in adult heart regeneration, the underlying intracellular mechanisms remain largely unknown. Here we show that H2O2 acts as a novel epicardial and myocardial signal to prime the heart for regeneration in adult zebrafish. Live imaging of intact hearts revealed highly localized H2O2 (~30 µM) production in the epicardium and adjacent compact myocardium at the resection site. Decreasing H2O2 formation with the Duox inhibitors diphenyleneiodonium (DPI) or apocynin, or scavenging H2O2 by catalase overexpression markedly impaired cardiac regeneration while exogenous H2O2 rescued the inhibitory effects of DPI on cardiac regeneration, indicating that H2O2 is an essential and sufficient signal in this process. Mechanistically, elevated H2O2 destabilized the redox-sensitive phosphatase Dusp6 and hence increased the phosphorylation of Erk1/2. The Dusp6 inhibitor BCI achieved similar pro-regenerative effects while transgenic overexpression of dusp6 impaired cardiac regeneration. H2O2 plays a dual role in recruiting immune cells and promoting heart regeneration through two relatively independent pathways. We conclude that H2O2 potentially generated from Duox/Nox2 promotes heart regeneration in zebrafish by unleashing MAP kinase signaling through a derepression mechanism involving Dusp6.