title: Extracellular GC-rich DNA activates TLR9- and NF-kB-dependent signaling pathways in human adipose-derived mesenchymal stem cells (haMSCs).
abstract: BACKGROUND
  The content of GC-rich ribosomal repeats (rDNA) in cell-free DNA (cfDNA) of patients with various diseases is several times higher as compared with genomic DNA (gDNA) and cfDNA of healthy donors. rDNA may act as Toll-like receptor 9 (TLR9) ligands and affect human adipose-derived mesenchymal stem cells (haMSCs). Here we explore effects of human cfDNAs and model rDNA fragments on cultured haMSCs.
  
  
  METHODS
  Both cfDNAs and cloned rDNA stimulate expression of TLR9 (qRT-PCR). Treatment with cloned rDNA leads to an increase in the number of TLR9(+) cells (FACS), expression levels for both TLR9 and Myd88, the translocation of nuclear factor-kappa B to the nuclei and up-regulation of TNFα and IL-10 cytokines (ELISA). As shown by an analysis of γH2AX-foci and MTT test, the preconditioning of haMSCs with cloned rDNA fragment increases the resistance of these cells to irradiation at 2Gy, while the treatments with control gDNA did not stimulate either TLR9- or NF-kB-dependent signaling pathways.
  
  
  CONCLUSIONS
  GC-rich sequences present in cfDNA stimulate endogenous stems cells when body is exposed to adverse conditions. GC-rich fragments of human DNA may be used for preconditioning of therapeutic MSCs aiming at an increase in their survival in the ailing body.
authors.affiliation: Research Centre for Medical Genetics, Russian Academy of Medical Sciences, Moscow, Russia.
authors.forename: Svetlana
authors.initials: S
authors.lastname: Kostjuk
authors.forename: Polina
authors.initials: P
authors.lastname: Loseva
authors.forename: Oksana
authors.initials: O
authors.lastname: Chvartatskaya
authors.forename: Elizaveta
authors.initials: E
authors.lastname: Ershova
authors.forename: Tatyana
authors.initials: T
authors.lastname: Smirnova
authors.forename: Elena
authors.initials: E
authors.lastname: Malinovskaya
authors.forename: Olga
authors.initials: O
authors.lastname: Roginko
authors.forename: Vladimir
authors.initials: V
authors.lastname: Kuzmin
authors.forename: Vera
authors.initials: V
authors.lastname: Izhevskaia
authors.forename: Ancha
authors.initials: A
authors.lastname: Baranova
authors.forename: Evgeny
authors.initials: E
authors.lastname: Ginter
authors.forename: Natalia
authors.initials: N
authors.lastname: Veiko
mesh_terms: D000273:Adipose Tissue / Q000166:cytology / Q000378:metabolism*; D002478:Cells, Cultured; D004247:DNA / Q000737:chemistry / Q000502:physiology*; D005434:Flow Cytometry; D020862:GC Rich Sequence; D006801:Humans; D007150:Immunohistochemistry; D016753:Interleukin-10 / Q000378:metabolism; D059630:Mesenchymal Stem Cells / Q000378:metabolism*; D016328:NF-kappa B / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D015398:Signal Transduction; D051217:Toll-Like Receptor 9 / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D015854:Up-Regulation
chemical_list: D016328:NF-kappa B; C495371:TLR9 protein, human; D051217:Toll-Like Receptor 9; D014409:Tumor Necrosis Factor-alpha; D016753:Interleukin-10; D004247:DNA