Enrichment of extracellular DNA from the cultivation medium of human peripheral blood mononuclears with genomic CpG rich fragments results in increased cell production of IL-6 and TNF-a via activation of the NF-kB signaling pathway

Previously, it was found that blood plasma extracellular DNA (ecDNA) of patients with rheumatoid arthritis (RA) is enriched with CpG-rich genomic DNA fragments, which contain TLR9 ligands (Veiko et al., 2006). In this study we have demonstrated that ecDNA of a RA patient and model fragments added to a cultivation medium of peripheral blood mononuclear cells (PBMC) of healthy donors stimulate expression of genes for the TLR9-MyD88-NF-kB signaling pathway; this leads to a significant increase in concentrations of the proinflammatory cytokines IL-6 and TNF-a in the cultivation medium. Human genomic DNA non-enriched with the CpG sequences did not stimulate IL-6 and TNF-a synthesis in PBMC. A scheme explaining the potential role ecDNA in the induction and maintenance of increased levels of the proinflammatory cytokines under conditions damaging the human cells has been proposed. Izvestno, chto vnekletochnaia DNK (vkDNK) plazmy krovi bol'nykh revmatoidnym artritom (RA) obogashchena fragmentami CpG-bogatykh genomnykh posledovatel'nosteĭ, kotorye kodiruiut ligandy retseptorov TLR9 (Veĭko i soavt., 2006). Nami pokazano, chto vkDNK bol'nogo RA i model'nye CpG-bogatye fragmenty genoma cheloveka, vvedennye v sredu kul'tivirovaniia mononuklearov perifericheskoĭ krovi (PBMC) zdorovykh donorov, stimuliruiut ékspressiiu genov signal'nogo puti TLR9–MyD88–NF-kB, chto privodit k znachitel'nomu uvelicheniiu kontsentratsii provospalitel'nykh tsitokinov – IL-6 i TNF-a – v srede kul'tivirovaniia. Neobogashchennaia CpG genomnaia DNK cheloveka inertna v otnoshenii stimuliatsii sinteza IL-6 i TNF-a v PBMC. Predlozhena skhema, ob"iasniaiushchaia potentsial'nuiu rol' vkDNK v induktsii i podderzhanii povyshennogo urovnia provospalitel'nykh tsitokinov v kletkakh, podvergnutykh deĭstviiu povrezhdaiushchikh faktorov.