Diagnosis of Canine Visceral Leishmaniasis by Flow Cytometry Serology using the rMELEISH Multiepitope Antigen Coupled in a Functional Bead

BACKGROUND

Visceral leishmaniasis (VL) is a zoonotic disease, with dogs being the main reservoir of the Leishmania infantum parasite.

OBJECTIVE

To develop a new flow cytometry test to diagnosis canine VL (CVL) diagnosis.

METHODS

The current study addresses a new flow cytometry test using beads coupled to the multiepitope antigen rMELEISH.

RESULTS

In the study set of samples a sensitivity (87.1%) and specificity (89.9%) was observed. Considering the dogs' clinical status, 20/20 (100.0%) of the symptomatic sera tested positive, while 19/22 (86.4%) of the oligosymptomatic and 16/20 (80.0%) of asymptomatic were positive. In the non-infected control, all samples (0/30) tested as negative. In the cross-reaction control, the test was more efficient in dogs infected with L. braziliensis (2/10) and Trypanosoma cruzi (0/10), than those with Babesia canis (4/10) and Ehrlichia canis (4/10). Dogs immunized with different vaccines (Leishmune, Leish-Tec®, or LBSap) did not present serological reactivity.

CONCLUSION

The flow cytometry serology through coupling the antigen rMELEISH in functional beads showed high accuracy in diagnosing CVL.

Diagnostic markers selected by immunoproteomics and phage display applied for the serodiagnosis of canine leishmaniosis

Canine leishmaniosis (CanL) is one of the most important parasitic diseases found in several countries worldwide. Dogs are considered important domestic reservoirs of the parasites, being relevant in the maintenance of transmission cycle of the disease between sandflies and humans. However, the prevalence of asymptomatic infection is considerably higher than that of apparent clinical illness in the infected animals; thus making promptly necessary to diagnose the infection in these animals, which could help to allow to the adoption of more efficient control measures against disease. Parasitological tests, which are considered as gold standard to demonstrate the infection and diagnose the disease, present problems related with their sensitivity. Also, the sample´s collect is considered invasive. As consequence, serological tests could be applied as an additional tool to detect the asymptomatic and symptomatic CanL. For this purpose, distinct recombinant antigens have been studied; however, problems in their sensitivity and/or specificity have been still registered. The present review focus in advances in the identification of new diagnostic targets applied for the CanL diagnose, represented here by recombinant single, combined or chimeric proteins, as well as by peptides that mimic epitopes (mimotopes); which were selected by means of immunoproteomics and phage display.

Expression and Biochemical Characterization of a Yersinia intermedia Phytase Expressed in Escherichia coli

BACKGROUND

Phytases are enzymes capable of degrading phytic acid and used in animal feed supplementation in order to improve digestibility through the release of minerals such as phosphorus.

OBJECTIVE

The main goal of this study was to express and characterize a Yersinia intermedia phytase expressed in Escherichia coli cells.

METHODS

The Y. intermedia phytase gene was synthesized and overexpressed in Escherichia coli cells. The phytase recombinante (rPHY) was purified to homogeneity using a Ni-NTA column. The biochemical and biophysical properties of the rPHY were measured in order to fully characterize the recombinant enzyme. The following patents database were consulted: Espacenet, USPTO, LATIPAT, Patent Scope, WIPO and Google Patents.

RESULTS

The results showed that the rPHY is active at 37-40ºC and presented an optimal pH and temperature of 8.0 and 40°C, respectively. The phytase rPHY was activated by Cu2+ ion and showed resistance to trypsin and pepsin, retaining 55% of the activity at the ratio of 0.02. Furthermore, the dissociation constant (Kd = 1.1150 ± 0.0087 mM), as estimated by a fluorescence binding assay, suggests a medium affinity of the enzyme with the substrate.

CONCLUSION

The results of this article can be considered as innovative and for this reason, they were protected by Intellectual Property Law in Brazil. Take together, the biochemical properties of the rPHY could be useful in future for its industrial application of this enzyme as an additive in the monogastric feed.

Abstract P4-05-01: Diet, development and predisposition to breast cancer: The impact of sugar derived metabolites (AGEs) on pubertal mammary gland development

The mammary gland is one of the few organs that continues to develop postnatally through stages including puberty, pregnancy, lactation, and involution. The gland is composed of epithelial and stromal cells that include fibroblasts, adipocytes, endothelial cells, nerve cells, and macrophages. Terminal end bud (TEB) structures are found exclusively in the pubertal developmental stage. The formation of TEBs and side branching drives mammary gland epithelial cell invasion into the mammary fat pad, continuing until the entire fat pad is filled. Pubertal mammary gland morphogenesis integrates a balance of epithelial cell proliferation, differentiation, and apoptosis. Several studies have shown that the interaction between mammary epithelial and stromal cells is crucial for the proper postnatal development of the mammary ductal tree. Interestingly, studies have shown that processes important in mammary gland development are often deregulated during breast cancer tumorigenesis. Thus, understanding the complex signaling network as well as the interactions between the different cell types during mammary gland development will be vital for elucidating the mechanisms underlying breast cancer progression and metastasis.

Glycation is the non-enzymatic glycosylation of sugar moieties to biological macromolecules such as protein and DNA which produces reactive metabolites known as advanced glycation end products (AGE's). AGE content in the Western Diet has consistently increased over the last 50 years due to increased consumption of sugar laden and cheap processed/manufactured foods which are high in reactive AGE metabolites. AGE containing food can lead to the accumulation of AGEs in the body overtime leading to pro-inflammatory and pro-oxidant effects when signaling through receptor for advanced glycation end products (RAGE). Leading too many complications associated with diseases including diabetes, Alzheimer's, heart disease and cancer. Preliminary data in our lab has shown that AGEs also have an effect on phosphorylation and signaling of estrogen receptor α (ERα), a key receptor and signaling pathway in the regulation of mammary gland development during puberty. This observation, together with the links between diet, mammary gland development and immune cell recruitment lead us to examine the biological effects of a diet high in AGEs on pubertal mammary gland development in mice. We observed a significant disruption of normal pubertal mammary gland development in mice fed a high AGE diet when compared to mice fed a control diet. Mice fed the high AGE diet showed increases in TEB number as well as width, length and area. We also observed an increase in ductal branching and a decrease in ductal extension. Future studies will assess the role of macrophage recruitment to the developing gland, specifically around the TEBs based on its reported role in normal TEB function. We also plan to assess ERa signaling in mice fed the high AGE diet based on the reported role of estrogen signaling in ductal elongation.

Citation Format: Krisanits BA, Nogueira LM, Findlay VJ, Turner DP. Diet, development and predisposition to breast cancer: The impact of sugar derived metabolites (AGEs) on pubertal mammary gland development [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P4-05-01.

Abstract P4-07-02: MicroRNA 204 mediated negative regulation of the IGF2R promotes breast cancer progression and is a potential mechanism driving breast cancer disparity

Breast cancer (BC) is a worldwide health issue as it represents the leading cause of cancer in women and the second leading cause of cancer-related mortality in women, with an increasing incidence. In the US, African American (AA) women have a significantly higher rate of mortality due to BC compared to Caucasian American (CA) women. It is becoming increasingly apparent that racial disparity in cancer exists due to molecular differences in tumor biology as well as, or in addition to, socioeconomic and standard of care issues. Sparse information exists regarding the molecular mechanisms that promote BC health disparity therefore, a greater understanding of the risk factors and biological links associated with BC, will significantly impact AA women. Our studies have identified a race specific mechanistic link between microRNA-204 (miR-204) and the Insulin-like Growth Factor-2 Receptor. MicroRNAs are small non-coding RNAs that function to inhibit gene expression through translational repression. Our published studies identified miR-204 as a novel oncomir and we recently identified IGF2R as a direct target. The IGF2R has been proposed to be a tumor suppressor gene in several cancers including breast cancer. We show that over-expression of miR-204 results in a decrease in IGF2R protein levels. We propose that the inhibition of IGF2R allows IGF-2 to bind the IGF1R leading to hyperactivation of this pathway which results in increased proliferation, migration and invasion, processes that are required for tumor progression. Indeed, we show that miR-204 expression results in the activation of the IGF1R/IRS-1/ERK pathway together with an increase in proliferation, migration and invasion. Published studies have shown that exogenous expression of activated IGF1R increases migration in non-transformed breast cells. We have shown that exogenous expression of miR-204 also increases migration in these cells. However, when miR-204 and IGF1R are both exogenously expressed no additional increase in migration was observed, suggesting that mIR-204 mediated increase in migration is through activation of the IGF1R pathway. Reduced IGF2R expression correlates with poor patient prognosis in BC patients and a recent study showed significantly higher levels of IGF2R in CA compared to AA tumor samples, suggesting that decreased IGF2R expression may contribute to BC disparity. We examined serum from BC patients and found elevated levels of miR-204 in AA compared to CA women. Circulating miRNAs can serve as accessible biomarkers for diagnosis & prognosis and may define a novel area of potential therapeutic intervention to reduce BC disparity. Our data also suggest that miR-204 mediated inhibition of IGF2R could be a potential biological mechanism driving BC disparity. A major hurdle to the identification of biological mechanisms conferring cancer health disparity is a lack of suitable experimental models with which to investigate race specific differences in tumor biology. We have developed a unique inducible miR-204 transgenic mouse model to define in vivo the oncogenic potential of miR-204 and the mechanism and functional consequences of IGF2R loss.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P4-07-02.