Effect of salivary gland extract of ticks on mouse embriyonic cells

Embryonic stem cells (ESCs) were first isolated in 1981 from mouse blastocysts. Shortly after their discovery, mouse ESCs (mESCs) became an indispensable tool in biomedical research. However, regulation of self–renewing and pluripotency factors is often very inefficient. Most stem cell laboratories still rely on conventional culture methods to support the expansion and maintenance of mESCs. Tick (Acari: Ixodidae) saliva has been shown to contain a wide range of bioactive molecules with vasodilatory, antihemostatic, and immunomodulatory activities. Previous studies have demonstrated negative effect of the tick saliva on activation of the mitogen-activated protein kinases (MAPK) and extracellular signal-regulated kinase (ERK) 1/2 pathways. Also there are evidences that activation of these pathways is negative regulator of mESCs' self-renewing. In this study we scrutinized the effect of tick saliva on traditional mESC culturing systems. In this study, to examine the toxic dose, extract of tick salivary gland were assayed on mESC cultures at different concentrations. mESCs lines isolated from CB6F1/J (Balbc X C57BL/6J) mice's blastocysts were cultured in stem cell mediums (Knock Out-KO DMEM+15 % KO Serum Replacement) with 6 different extract concentrations (0.2 µg/ml, 2 µg/ml, 20 µg/ml, 40 µg/ml, 80 µg/ml, 160 µg/ml) of 3 different species from ticks (D. marginatus, R. bursa and H. marginatum) in 37 °C and 5 % CO2 incubator for 7 days. Viable cells were detected with Cell Titer Glu (CTG) assay. Our results suggest that traditional mESCs medium supplemented with 80 µg/ml tick saliva from D. marginatus have positive effect on mESCs' proliferation rate. Beside that, to understand which factor or proteins in tick saliva affect proliferation and maintenance of mESCs, proteomics analysis and some other experiments are needed.