Signaling TLR/RLR-mechanisms of immunomodulating action of ingavirin and thymogen preparations

Objective: to study drugs ingavirin and thymogen as activators of signal TLR and RLR reactions in a sensitive cell model of THP-1 monocytes and blood cells of donors.
Materials and methods . Investigated drugs ingavirin (imidazolylethanamide pentanedioic acid – 6-[2-(1H-imidazol-4-yl)ethylami- no]-5-oxohexanoic acid; Valenta Pharmaceutics, Russia) and thymogen (alpha-glutamyl-tryptophan; Cytomed, Russia), registered in Russia as medicines. The expression of TLR/RLR receptor genes was determined under the action of ingavirin 50–300 μg/ml and thymogen 0.1–5 μg/ml (24 h, 37 °C) using quantitative RT-PCR. The level of fluid cytokines was determined using ELISA kits (Vec- tor-Best, Russia) in the culture fluid. Transfection of small inhibitory RNA (siRNA) MAVS was performed using the reagent Lipofect- amine 2000 (Invitrogen). The immunophenotype of the THP-1 cell line was determined by flow cytometry with labeled monoclonal antibodies FITC CD14 and PE CD34 (BD Biosciences) on a FACSCanto II instrument (Becton Dickinson).
Results . For the first time, it has been shown that ingavirin (imidazolylethanamide) and thymogen (dipeptide Glu-Trp) preparations are activators of the immune TLR/RLR receptors and their signaling factors genes in the cultures of monocytic leukemia THP-1 and blood of healthy donors. In these cellular systems, ingavirin and thymogen preparations elicited similar immune responses and stimulated the expression of genes: endosomal TLR3/7/8/9 receptors, RIG1/MDA5 cytoplasmic sensors and NFκB1 and MAVS signaling factors. Induced cells secrete inflammatory cytokines of TNF-α and IL1-β. Ingavirin in THP-1 cell culture monocytes caused a decrease in CD34+ blast cells. Activation the genes of MAVS and co-receptor B2M of the main histocompatibility complex (MHCII) by ingavirin were interrelated. Transfection of siRNA MAVS reduced the level of homologous mRNA MAVS and heterologous mRNA B2M. Conclusion . The results obtained suggest that the antiviral and immunomodulating properties of the drugs ingavirin and thymogen are associated with the activation of a group of TLR/RLR signaling pathways of the innate and adaptive immunity and the differentiation of hematopoietic cell precursors.