Mosquito immune responses and compatibility between Plasmodium parasites and anopheline mosquitoes

<p>Abstract</p> <p>Background</p> <p>Functional screens based on dsRNA-mediated gene silencing identified several <it>Anopheles gambiae </it>genes that limit <it>Plasmodium berghei </it>infection. However, some of the genes identified in these screens have no effect on the human malaria parasite <it>Plasmodium falciparum</it>; raising the question of whether different mosquito effector genes mediate anti-parasitic responses to different <it>Plasmodium </it>species.</p> <p>Results</p> <p>Four new <it>An. gambiae </it>(G3) genes were identified that, when silenced, have a different effect on <it>P. berghei </it>(Anka 2.34) and <it>P. falciparum </it>(3D7) infections. Orthologs of these genes, as well as <it>LRIM1 </it>and <it>CTL4</it>, were also silenced in <it>An. stephensi </it>(Nijmegen Sda500) females infected with <it>P. yoelii </it>(17XNL). For five of the six genes tested, silencing had the same effect on infection in the <it>P. falciparum-An. gambiae </it>and <it>P. yoelii-An. stephensi </it>parasite-vector combinations. Although silencing <it>LRIM1 </it>or <it>CTL4 </it>has no effect in <it>An. stephensi </it>females infected with <it>P. yoelii</it>, when <it>An. gambiae </it>is infected with the same parasite, silencing these genes has a dramatic effect. In <it>An. gambiae </it>(G3), TEP1, LRIM1 or LRIM2 silencing reverts lysis and melanization of <it>P. yoelii</it>, while <it>CTL4 </it>silencing enhances melanization.</p> <p>Conclusion</p> <p>There is a broad spectrum of compatibility, the extent to which the mosquito immune system limits infection, between different <it>Plasmodium </it>strains and particular mosquito strains that is mediated by TEP1/LRIM1 activation. The interactions between highly compatible animal models of malaria, such as <it>P. yoelii </it>(17XNL)-<it>An. stephensi </it>(Nijmegen Sda500), is more similar to that of <it>P. falciparum </it>(3D7)-<it>An. gambiae </it>(G3).</p

Cytokines increase engraftment of human acute myeloid leukemia cells in immunocompromised mice but not engraftment of human myelodysplastic syndrome cells

Patient-derived xenotransplantation models of human myeloid diseases including acute myeloid leukemia, myelodysplastic syndromes and myeloproliferative neoplasms are essential for studying the biology of the diseases in pre-clinical studies. However, few studies have used these models for comparative purposes. Previous work has shown that acute myeloid leukemia blasts respond to human hematopoietic cytokines whereas myelodysplastic syndrome cells do not. We compared the engraftment of acute myeloid leukemia cells and myelodysplastic syndrome cells in NSG mice to that in NSG-S mice, which have transgene expression of human cytokines. We observed that only 50% of all primary acute myeloid leukemia samples (n=77) transplanted in NSG mice provided useful levels of engraftment (>0.5% human blasts in bone marrow). In contrast, 82% of primary acute myeloid leukemia samples engrafted in NSG-S mice with higher leukemic burden and shortened survival. Additionally, all of 5 injected samples from patients with myelodysplastic syndrome showed persistent engraftment on week 6; however, engraftment was mostly low

Evidence of an oncogenic gammaherpesvirus in domestic dogs

AbstractIn humans, chronic infection with the gammaherpesvirus Epstein–Barr virus is usually asymptomatic; however some infected individuals develop hematological and epithelial malignancies. The exact role of EBV in lymphomagenesis is poorly understood partly because of the lack of clinically relevant animal models. Here we report the detection of serological responses against EBV capsid antigens in healthy dogs and dogs with spontaneous lymphoma and that dogs with the highest antibody titers have B cell lymphoma. Moreover, we demonstrate the presence of EBV-like viral DNA and RNA sequences and Latent Membrane Protein-1 in malignant lymph nodes of dogs with lymphoma. Finally, electron microscopy of canine malignant B cells revealed the presence of classic herpesvirus particles. These findings suggest that dogs can be naturally infected with an EBV-like gammaherpesvirus that may contribute to lymphomagenesis and that dogs might represent a spontaneous model to investigate environmental and genetic factors that influence gammaherpesvirus-associated lymphomagenesis in humans

Use of a Glycolipid Inhibitor to Ameliorate Renal Cancer in a Mouse Model

<div><p>In a xenograft model wherein, live renal cancer cells were implanted under the kidney capsule in mice, revealed a 30-fold increase in tumor volume over a period of 26 days and this was accompanied with a 32-fold increase in the level of lactosylceramide (LacCer). Mice fed D- threo-1-phenyl-2-decanoylamino-3-morpholino-1-propanol (D-PDMP), an inhibitor of glucosylceramide synthase and lactosylceramide synthase (LCS: β-1,4-GalT-V), showed marked reduction in tumor volume. This was accompanied by a decrease in the mass of lactosylceramide and an increase in glucosylceramide (GlcCer) level. Mechanistic studies revealed that D-PDMP inhibited cell proliferation and angiogenesis by inhibiting p44MAPK, p-AKT-1 pathway and mammalian target for rapamycin (mTOR). By linking glycosphingolipid synthesis with tumor growth, renal cancer progression and regression can be evaluated. Thus inhibiting glycosphingolipid synthesis can be a bonafide target to prevent the progression of other types of cancer.</p></div

D-PDMP reduced tumor volume in mice.

<p>Mice (BALB/C) were pre-anesthetized and RENCA tumor cell suspension (10⁶ cells) was injected in the subcapsular space of the left kidney. Experimental treatment began two days after subcapsular tumor implantation. Mice fed by oral gavage D-PDMP (3 and 10 mg/kg body weight, MPK) daily. D-PDMP was solubilized in 5% Tween-80 in saline. Placebo mice received the vehicle (5% Tween-80 in saline 100 µl only). After 26 days, the mice were sacrificed. The right kidney served as control, and the left kidney served as placebo or drug treated with 3 and 10 MPK of D-PDMP. <b>A</b>: A marked increase in mouse kidney tumor volume is sharply decreased by feeding D-PDMP. <b>B</b>. D-PDMP (3 and 10 MPK) did not reduce total body weight in mice. <b>C</b>: The level of D-PDMP in kidney of mice treated with 3 and 10 MPK of D-PDMP were similar.</p

D-PDMP treatment altered the levels of several sphingolipids but not sphingomyelin in mice renal cancer.

<p>The level of various sphingolipids were measured by tandem LC-MS/MS. <b>A</b>: D-PDMP decreased the level of ceramide, <b>B</b>: ceramide-1-phosphate, and <b>D</b>: sphingosine-1-phosphate. D-PDMP modestly increased the level of sphingosine; <b>C</b>, <b>E</b>: sphinganine and <b>F</b>: monohexosylceramide. <b>G</b>: D-PDMP dose-dependently decreased the level of dihexosylceramide in mice renal cancer. <b>H</b>: D-PDMP did not change the level of sphingomyelin in mouse renal cancer. (* p<.05, **p<.01 N = 4).</p

D-PDMP decreased the activity of glycosyltransferases and glycohydrolase in mouse renal cancer.

<p>Measurement of lactosylceramide synthase activity in mouse kidney was conducted using UDP[14C] galactose as galactose donor and GlcCer as the acceptor, as detailed <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0063726#pone.0063726-Chatterjee3" target="_blank">[11]</a>. We observed that feeding D-PDMP dose-dependently decreased the activity of this enzyme <b>A</b>: glucosylceramide synthase activity was decreased to the same extent irrespective of whether 3 MPK or 10 MPK of D-PDMP was fed to mice with renal cancer, <b>B</b>: glucosylceramidehydrolase activity was decreased by D-PDMP treatment and <b>C</b>: lactosylceramide synthase activity was dose-dependently decreased in D-PDMP fed mice with renal cancer (N = 4; *p<.05).</p

NBD peptide promotes apoptosis and reduces tumor burden in a subset of dogs with ABC-like DLBCL.

<p><b>A</b>. Malignant lymph node tissue sections taken before (pre-) and 24 hours after (post-) NBD peptide treatment were stained using TUNEL and counterstained with DAPI. <b>B</b>. Apototic cells were counted in 10 high power fields and the average number of positive cells was determined for both pre- and post-treatment sections. <b>C</b>. Calculated percent decrease in tumor mass 24 hours after NBD peptide treatment. Measureable tumor burden was determined pre and 24 hours post NBD peptide treatment and the percentage change in tumor burden was calculated. ND (Not Determined).</p

Systemic administration of NBD peptide inhibits IKK and IκBα phosphorylation in malignant lymphoid tissue.

<p>Biopsies of malignant lymph nodes taken before (pre-) and 24 hours after (post-) NBD peptide administration were evaluated for the presence of phospho-IKKα/β and phospho-IκBα by immunoblot. <b>A</b>. Immunoblots for phospho-IKKα/β and IKKβ and phospho-IκBα and IκBα. Immunoblots were evaluated by densitometry and the ratios of <b>B</b>. phospho-IKKα/β:IKKβ and <b>C</b>. phospho-IκBα:IκBα were calculated. ND (Not Determined).</p

NBD inhibits the expression of canonical NF-κB target genes in a subset of dogs with ABC-like DLBCL.

<p>NF-κB target gene expression within malignant lymph node tissues before and 24 hours after NBD peptide administration was determined by qRT-PCR. The relative quantification of gene expression in post treatment samples was normalized to pre-treatment values for each dog. β-actin was used as an endogenous control and all assays were performed in triplicate. p values are calculated on dCt data, ^★p<0.05, ^★★p<0.005.</p