Transcriptomic of Blood and Liver Tissues of Caiman latirostris through Next Generation Sequencing after Acute Exposure to Glyphosate-base Formulation Roundup®

GISELA LAURA POLETTA; MARIA VIRGINIA PARACHÚ MARCÓ; EVELYN CECILIA LOPEZ GONZALEZ; NANCY DENSLOW; PABLO ARIEL SIROSKI

Santa Fe

Congreso; 25th Working Meeting of the IUCN-SSC Crocodile Specialist Group; 2018

Universidad Nacional del Litoral - Proyecto Yacare

A major challenge in the emerging field of toxicogenomics is to define the relationships between chemically induced changes in gene expression and alterations in conventional toxicologic parameters. Fundamental assumptions are that all toxicological relevant effects are accompanied by gene expression changes. The tremendous progress in the development of new technologies in molecular biology and bioinformatics enables interrogation of cellular responses to toxicant treatment at a global molecular level, allowing the evaluation of toxic effects in the context of molecular pathways. The aim of this study was to analyze gene expression profile of blood and liver samples obtained from juvenile caiman after exposure to the widely used glyphosate-based herbicide formulation Roundup®. Eight juvenile males of C. latirostris were distributed in two experimental groups: a negative control and a treated group exposed to Roundup® Full II. Animals were maintained under controlled conditions of temperature (30 ± 2 ºC) into plastics containers and the exposure was performed by voluntary immersion in water, at a concentration of 8 mg/l of RU during one week. After exposure, blood and liver samples were taken to all animals and immediately frozen in liquid nitrogen and storage at -80°C until processing. TRIzol reagent was used for RNA extraction following protocols previously adapted for the specie. All liver samples showed good RNA integrity numbers (RIN) but RNA from blood was purified with the Zymo Research column to obtain suitable values for the library construction. We used the NEBNext Ultra II Directional RNA Library Prep Kit for Illumina for libraries preparation (DNA 0.1-5.0 μg) and then DNA was sequenced using Illumina sequencing Technology (NGS). Bioinformatics analysis showed that from those genes identified in blood, have significantly different expression levels between exposed and control caiman. From them, 106 (52.74%) were downregulated and 95 (47.26 %) were upregulated in exposed animals. In the case of liver, from the identified genes, 605 demonstrated a significant different expression level and from them, 478 (79.00 %) were downregulated while 127 (21.00 %) were upregulated in exposed caiman respect to controls. Then, we performed a Functional Annotation analysis using DAVID Bioinformatic database in order to identified Gene enrichment clusters among deregulated genes. All these data contribute to understand the relationship between temporal changes in gene expression and conventional toxicology endpoints, and facilitate the phenotypic anchoring of toxicogenomic data. Besides, biomarker genes or signatures of certain toxic effects may be derived from this study