Zebrafish as a Smart Model to Understand Regeneration After Heart Injury: How Fish Could Help Humans.

Myocardial infarction (MI) in humans is a common cause of cardiac injury and results in irreversible loss ofmyocardial cells and formation of fibrotic scar tissue. This fibrotic tissue preserves the integrity of the ventricular wall but undermines pump function, leading to congestive heart failure. Unfortunately, the mammalian heart is unable to replace cardiomyocytes, so the life expectancy for patients after an episode of MI is lower than for most common types of cancers. Whereas, humans cannot efficiently regenerate their heart after injury, the teleost zebrafish have the capability to repair a \u201cbroken\u201d heart. The zebrafish is probably one of the most important models for developmental and regenerative biology of the heart. In the last decades, the zebrafish has become increasingly important for scientific research: it has many characteristics that make it a smart model for studying human disease. Moreover, adult zebrafish efficiently regenerate their hearts following different forms of injury. Due to these characteristics, and to the availability of genetic approaches, and biosensor zebrafish lines, it has been established useful for studying molecular mechanisms of heart regeneration. Regeneration of cardiomyocytes in zebrafish is not based on stemcells or transdifferentiation of other cells but on the proliferation of preexisting cardiomyocytes. For this reason, future studies into the zebrafish cardiac regenerative mechanisms could identify specific molecules able to regulate the proliferation of preexisting cardiomyocytes; these factors may be studied in order to understand regulation of myocardial plasticity in cardiac repair processes after injury and, in particular, after MI in humans

Genomic and structural investigation on dolphin morbillivirus (DMV) in Mediterranean fin whales (Balaenoptera physalus).

Dolphin morbillivirus (DMV) has been deemed as one of the most relevant threats for fin whales (Balaenoptera physalus) being responsible for a mortality outbreak in the Mediterranean Sea in the last years. Knowledge of the complete viral genome is essential to understand any structural changes that could modify virus pathogenesis and viral tissue tropism. We report the complete DMV sequence of N, P/V/C, M, F and H genes identified from a fin whale and the comparison of primary to quaternary structure of proteins between this fin whale strain and some of those isolated during the 1990-'92 and the 2006-'08 epidemics. Some relevant substitutions were detected, particularly Asn52Ser located on F protein and Ile21Thr on N protein. Comparing mutations found in the fin whale DMV with those occurring in viral strains of other cetacean species, some of them were proven to be the result of diversifying selection, thus allowing to speculate on their role in host adaptation and on the way they could affect the interaction between the viral attachment and fusion with the target host cells

Inhibition of catalase activity as an early response of Arabidopsis thaliana cultured cells to the phytotoxin fusicoccin

In Arabidopsis thaliana cells, fusicoccin (FC) treatment induced an early and marked increase in the extracellular H(2)O(2) level. It also increased the huge hypo-osmotic stress-induced oxidative wave and, in addition, prevented the H(2)O(2) peak drop. These effects were apparently not linked to changes in either cytoplasmic pH or cytoplasmic free calcium concentration, since they occurred independently of the activity state of the plasma membrane (PM) H(+)-ATPase and neither influx nor efflux of (45)Ca(2+) was modified by FC. In the presence of diphenylene iodonium (DPI), inhibiting the PM NADPH oxidase presumably responsible for reactive oxygen species (ROS) production, no apoplastic H(2)O(2) development was detected either with or without FC. However, no increase in DPI-sensitive ferricyanide reduction, but rather a gradual decrease, occurred with FC. These results suggested that the H(2)O(2) increase observed with FC was not due to a overproduction of ROS but, more probably, to a reduced capability of FC-treated cells to degrade the H(2)O(2) formed. This view, at first supported by the finding that FC-treated cells failed to break down exogenously supplied H(2)O(2), was clearly confirmed by a series of measurements on exogenous catalase activity, tested in cell-free media of FC-treated samples. This assay, in fact, allowed ascertainment and partial characterization of an as yet unidentified factor increasingly accumulating in the incubation medium of FC-treated cells, behaving as a non-competitive catalase inhibitor and able to reduce markedly the cell's capability for H(2)O(2) scavenging

Hepatic vein pressure determination and phlebography in the evaluation of portal hypertension

Click on the link to view

Genomic and structural investigation on Dolphin Morbillivirus (DMV) in Mediterranean fin whales (Balaenoptera physalus)

Dolphin Morbillivirus (DMV) has been deemed as one of the most relevant threats for fin whales (Balaenoptera physalus) being responsible for a mortality outbreak in the Mediterranean Sea in the last years. Knowledge of the complete viral genome is essential to understand any structural changes that could modify virus pathogenesis and viral tissue tropism. We report the complete DMV sequence of N, P/V/C, M, F and H genes identified from a fin whale and the comparison of primary to quaternary structure of proteins between this fin whale strain and some of those isolated during the 1990-‘92 and the 2006-‘08 epidemics. Some relevant substitutions were detected, particularly Asn52Ser located on F protein and Ile21Thr on N protein. Comparing mutations found in the fin whale DMV with those occurring in viral strains of other cetacean species, some of them were proven to be the result of diversifying selection, thus allowing to speculate on their role in host adaptation and on the way they could affect the interaction between the viral attachment and fusion with the target host cells

Mediterranean Fin Whales (Balaenoptera physalus) Threatened by Dolphin MorbilliVirus

During 2011-2013, dolphin morbillivirus was molecularly identified in 4 stranded fin whales from the Mediterranean Sea. Nucleoprotein, phosphoprotein, and hemagglutinin gene sequences of the identified strain were highly homologous with those of a morbillivirus that caused a 2006-2007 epidemic in the Mediterranean. Dolphin morbillivirus represents a serious threat for fin whales

Zebrafish models for ARVC8 analysis and drug discovery

INTRODUCTION: Desmoplakin is one the most abundant desmosomal proteins in cardiac and epithelial tissues. In humans, dominat mutations in the desmoplakin gene (DSP) cause Arrhythmogenic Right Ventricular Cardio​myopathy 8 (ARVC8), a dominant cardiomyopathy, frequently involved in juvenile sudden death. Current ARVC models are based on cell lines and transgenic mice. In this context, it has been shown that suppression of DSP expression leads to a reduction in canonical Wnt signaling, suggesting that this pathway could be a molecular target for ARVC therapeutic intervention. In order to address this issue, the present study aims to evaluate the pathogenic mechanisms of DSP mutations in vivo, using zebrafish (Danio rerio) as an innovative model for this disease. In zebrafish, the desmoplakin gene is present with two isoforms, dspa and dspb, both orthologous to the single DSP in humans. PURPOSE: The purpose of this study is the generation and the phenotypic characterization of transient ARVC8 zebrafish models using a morpholino-mediated knock-down strategy. In addition, by taking advantage of zebrafish pathway reporter lines, we aim to verify if Wnt signaling and/or other molecular cascades might be involved in ARVC8 pathogenesis. The final goal is the assessment of our ARVC8 model as a suitable tool for molecularly-targeted drug discovery. METHODS: To evaluate the expression of dspa and dspb during zebrafish embryonic development and adulthood, we used whole-mount in situ hybridization (WISH) and semi quantitative RT_PCR. Knockdown of zebrafish dspa and dspb genes was obtained by a morpholino (MO)-based antisense strategy. Specifically, we injected anti-dspa and anti-dspb MO oligos in both wild types and pathway-specific lines reporting the activity of Wnt, Bmp, TGFbeta, FGF, Shh, Notch, CREB, Hippo and Hypoxia signaling. RESULTS: We found that both dspa and dspb are expressed during zebrafish embryonic development, while the molecular analysis of cDNAs from different adult tissues demonstrates that both dspa and dspb are highly expressed in heart and skin, with dspa more strongly detectable compared to dspb. MO-mediated knock-down of both dspa and dspb leads to delayed development, microcephaly, pericardial edema and, particularly in dspb knock-down embryos, decreased heart rate. TEM analysis of cardiac and skin tissues under dspa+dspb simultaneous knock-down shows reduced and disorganized desmososmes. As far as concerns the analysis of previously mentioned signaling pathways, we observed a specific reduction of Wnt signaling responsiveness in the cardiac region of both dspa and dspb knock- down embryos (Fig. 1). CONCLUSION: Our results show that transient knock-down of zebrafish desmoplakin genes is able to phenocopy some ARVC8 features, such as cardiac and cutaneous desmosomal defects, heart rate alteration and Wnt signaling reduction, pointing to zebrafish as a suitable ARVC8 model for in vivo screening of molecularly-targeted drugs

Genomic insights into cardiomyopathies: a comparative cross-species review

n the global human population, the leading cause of non-communicable death is cardiovascular disease. It is predicted that by 2030, deaths attributable to cardiovascular disease will have risen to over 20 million per year. This review compares the cardiomyopathies in both human and non-human animals and identifies the genetic associations for each disorder in each species/taxonomic group. Despite differences between species, advances in human medicine can be gained by utilising animal models of cardiac disease; likewise, gains can be made in animal medicine from human genomic insights. Advances could include undertaking regular clinical checks in individuals susceptible to cardiomyopathy, genetic testing prior to breeding, and careful administration of breeding programmes (in non-human animals), further development of treatment regimes, and drugs and diagnostic technique