The septate junction component bark beetle is required for Drosophila intestinal barrier function and homeostasis

Age-related loss of intestinal barrier function has been documented across species, but the causes remain unknown. The intestinal barrier is maintained by tight junctions (TJs) in mammals and septate junctions (SJs) in insects. Specialized TJs/SJs, called tricellular junctions (TCJs), are located at the nexus of three adjacent cells, and we have shown that aging results in changes to TCJs in intestines of adult Drosophila melanogaster. We now demonstrate that localization of the TCJ protein bark beetle (Bark) decreases in aged flies. Depletion of bark from enterocytes in young flies led to hallmarks of intestinal aging and shortened lifespan, whereas depletion of bark in progenitor cells reduced Notch activity, biasing differentiation toward the secretory lineage. Our data implicate Bark in EC maturation and maintenance of intestinal barrier integrity. Understanding the assembly and maintenance of TCJs to ensure barrier integrity may lead to strategies to improve tissue integrity when function is compromised.

Expression of chronic myeloid leukemia oncogenes BCR-ABL P210 and BCR-ABL T315I affect cellular and humoral innate immunity in Drosophila melanogaster

Chronic myeloid leukemia (CML) is a myeloproliferative neoplasm that results from a chromosomal translocation between chromosome 9 and chromosome 22. The resulting fusion gene ( BCR-ABL ) encodes a constitutively active BCR-ABL tyrosine kinase. Some mutations of this oncogene, especially the Threonine 315 to Isoleucine substitution of the ABL kinase is resistant to first and second-generation tyrosine kinase inhibitors (TKIs) conventionally used in CML therapy. We have previously validated a CML fruit fly model for drug screening using the adult fly compound eye. Here we expressed wild-type BCR-ABL ^P210 and mutated BCR-ABL ^T315I in Drosophila melanogaster hematopoietic system to understand the phenotypic consequences of this expression and its impact on innate immune pathways. Flies expressing both wild-type BCR-ABL^P210 and mutant BCR-ABL^T315I showed increased number of circulating hemocytes, disruption in sessile patterning of resident hemocytes, dysregulation in the humoral Toll, ImD, and JAK/STAT pathways at the mRNA level in both the 3 ^rd instar larva and adult stages. Of note, BCR-ABL^T315I flies presented more severe phenotypes and a higher deviation in humoral dysregulation than BCR -ABL^P210 flies pointing towards more complex oncogenic effect of this mutant which requires further investigation.

Drosophila melanogaster as a Model System to Assess the Effect of Epstein-Barr Virus DNA on Inflammatory Gut Diseases

The Epstein-Barr virus (EBV) commonly infects humans and is highly associated with different types of cancers and autoimmune diseases. EBV has also been detected in inflamed gastrointestinal mucosa of patients suffering from prolonged inflammation of the digestive tract such as inflammatory bowel disease (IBD) with no clear role identified yet for EBV in the pathology of such diseases. Since we have previously reported immune-stimulating capabilities of EBV DNA in various models, in this study we investigated whether EBV DNA may play a role in exacerbating intestinal inflammation through innate immune and regeneration responses using the Drosophila melanogaster model. We have generated inflamed gastrointestinal tracts in adult fruit flies through the administration of dextran sodium sulfate (DSS), a sulfated polysaccharide that causes human ulcerative colitis- like pathologies due to its toxicity to intestinal cells. Intestinal damage induced by inflammation recruited plasmatocytes to the ileum in fly hindguts. EBV DNA aggravated inflammation by enhancing the immune deficiency (IMD) pathway as well as further increasing the cellular inflammatory responses manifested upon the administration of DSS. The study at hand proposes a possible immunostimulatory role of the viral DNA exerted specifically in the fly hindgut hence further developing our understanding of immune responses mounted against EBV DNA in the latter intestinal segment of the D. melanogaster gut. These findings suggest that EBV DNA may perpetuate proinflammatory processes initiated in an inflamed digestive system. Our findings indicate that D. melanogaster can serve as a model to further understand EBV-associated gastroinflammatory pathologies. Further studies employing mammalian models may validate the immunogenicity of EBV DNA in an IBD context and its role in exacerbating the disease through inflammatory mediators.

Ten-eleven translocation proteins and their role beyond DNA demethylation - what we can learn from the fly

Ten-eleven Translocation (TET) proteins have emerged as a family of epigenetic regulators that are important during development and have been implicated in various types of cancers. TET is a highly conserved protein that has orthologues in almost all multicellular organisms. Here, we review recent literature on the novel substrate specificity of this family of DNA 5-methylcytosine demethylases on DNA 6-methyladenine and RNA 5-methylcytosine that were first identified in the invertebrate model Drosophila. We focus on the biological role of these novel epigenetic marks in the fruit fly and mammals and highlight TET proteins' critical function during development specifically in brain development.

6117Persistent LBBB and AV block with high-burden RV pacing following transcatheter aortic valve replacement are associated with new onset cardiomyopathy

Background

Left bundle branch block (LBBB) and AV nodal block (AVB) requiring permanent pacemaker implantation occur frequently following transcatheter aortic valve replacement (TAVR) and may be associated with adverse clinical events.

Objectives

The study aims to assess the incidence of new onset cardiomyopathy among patients with normal left ventricular systolic function patients who developed LBBB or persistent AVB with high-burden right ventricular (RV) pacing (>80%) following TAVR procedure.

Methods

Consecutive patients who underwent TAVR procedure from January 2012 to June 2017 at the University of Michigan Health System were included in the retrospective analysis. Those who had a preexisting cardiac implantable electronic device (CIED), prior LBBB, left ventricular ejection fraction (LVEF) <50%, and follow up period less than 1 year were excluded from this analysis. New onset cardiomyopathy was defined by a left ventricular ejection fraction (LVEF) <45% within 1 year after TAVR.

Results

A total of 362 patients were included in the study (mean age 76.9±11.5 years, 56.1% male). Of these, 30 patients (8.3%) developed persistent AVB and required >80% RV pacing (pacing group), 61 patients (16.9%) developed persistent LBBB (LBBB group), and 271 patients (74.9%) did not have LBBB or AVB or required <80% RV pacing (control group). Baseline LVEF was 63.9+6.4% in pacing group (p=0.76) and 64.4+7.4% in LBBB group (p=0.89) compared to 64.3+6.5% in control group. Within 1 year after TAVR, 10/30 patients (33.3%) in pacing group (p<0.01) and 20/61 patients (32.8%) in LBBB (p<0.01) developed new onset cardiomyopathy compared to 9/271 patients (3.3%) in control group. LVEF at 1 year was 53.8+11.9% in pacing group (p<0.01) and 53.7+12.1% in LBBB group (p<0.01) compared to 64.8+7.7% in control group.

Conclusion

Among patients with normal baseline left ventricular systolic function, AV block required high-burden RV pacing and persistent LBBB following TAVR were associated with significantly higher incidence of new onset cardiomyopathy.

Prediction of violence on a psychiatric intensive care unit

The aim of the present study was to identify patients who were at particular risk of violent behaviour, over a period of one month in a psychiatric high dependency unit, and to examine whether particular patients could be identified at admission who would subsequently be violent. Medical records, and other documents for 52 inpatients were included. Demographic, historical and clinical data available at admission were noted. All violent incidents were recorded and classified. Seventeen of 52 patients committed physical violence, usually to the staff. Most incidents were carried out by a small number of individuals. Identifying the violent, using variables available at admission, was not possible. The ward admitted a group with a subsequent high rate of violence. Prediction within this high-risk group was not possible. Measures aimed at preventing violence on a local secure ward should apply to all patients and should not be targeted just at those that would appear to be the most likely to be violent.

Neutron activation of iron tablets to evaluate the effects of glycine on iron absorption

Neutron bombardment (neutron flux, 3 X 10(12) neutrons/cm2/s) of prepared iron tablets containing glycine-iron or iron alone was performed to prepare radioactive tablets to assess the effects of glycine on iron absorption from tableted formulations. No interfering isotopes of sufficient quantity were generated during neutron activation of the iron tablets. Cobalt-60 was the major trace mineral detected and accounted for only 1.3% of the total activity. There may have been trace amounts of zinc-65 or chromium-51 present, but they were not detectable above background radioactivity in the final tablet produced. Iron-59 represented greater than 98% of the radioactivity present in the tablets used in the study. Glycine-containing iron tablets produced dramatically higher amounts of iron in blood and tissues of rabbits (p less than 0.05) than did the same tablet formulations without glycine. The area under the iron blood concentration-time curve over 4 h increased by 67% with glycine added to the formulation over control iron tablets. Iron concentrations in tissues 4 h after iron administration was in the order of blood greater than liver greater than heart greater than kidney greater than muscle.

Effects of divalent amino acids on iron absorption

Solutions of each of 10 amino acids or ascorbic acid were mixed with iron and orally administered to rats. Iron was absorbed to a statistically significantly greater extent (p less than 0.05) when mixed with asparagine, glycine, serine, or ascorbic acid as compared with a control solution of iron. The largest effects were for asparagine and glycine, which also increased iron absorption to a significantly greater extent (p less than 0.001) than did serine or ascorbic acid. No statistically significant increase in iron absorption occurred when any of the other amino acids was mixed with iron. The extent of iron absorption from each test solution, as measured by area under the concentration of iron-59 in the blood-time curve (r2 = 0.0002), and the initial rate of iron absorption for each test solution (r2 = 0.01) showed no correlation with the stability constant of the amino acid-iron complex.