title: The role of tumour necrosis factor-α and tumour necrosis factor receptor signalling in inflammation-associated systemic genotoxicity.
abstract: Chronic inflammatory diseases are characterised by systemically elevated levels of tumour necrosis factor (TNF)-α, a proinflammatory cytokine with pleiotropic downstream effects. We have previously demonstrated increased genotoxicity in peripheral leukocytes and various tissues in models of intestinal inflammation. In the present study, we asked whether TNF-α is sufficient to induce DNA damage systemically, as observed in intestinal inflammation, and whether tumour necrosis factor receptor (TNFR) signalling would be necessary for the resultant genotoxicity. In the wild-type mice, 500 ng per mouse of TNF-α was sufficient to induce DNA damage to multiple cell types and organs 1-h post-administration. Primary splenic T cells manifested TNF-α-induced DNA damage in the absence of other cell types. Furthermore, TNFR1(-/-)TNFR2(-/-) mice demonstrated decreased systemic DNA damage in a model of intestinal inflammation and after TNF-α injection versus wild-type mice, indicating the necessity of TNFR signalling. Nuclear factor (NF)-κB inhibitors were also able to decrease damage induced by TNF-α injection in wild-type mice. When TNF-α administration was combined with interleukin (IL)-1β, another proinflammatory cytokine, DNA damage persisted for up to 24 h. When combined with IL-10, an anti-inflammatory cytokine, decreased genotoxicity was observed in vivo and in vitro. TNF-α/TNFR-mediated signalling is therefore sufficient and plays a large role in mediating DNA damage to various cell types, subject to modulation by other cytokines and their mediators.
authors: Department of Pathology and Laboratory Medicine, School of Medicine, University of California, Los Angeles, 650 Charles E. Young Drive South, Los Angeles, CA 90095, USA.
authors: Aya M
authors: AM
authors: Westbrook
authors: Bo
authors: B
authors: Wei
authors: Katrin
authors: K
authors: Hacke
authors: Menghang
authors: M
authors: Xia
authors: Jonathan
authors: J
authors: Braun
authors: Robert H
authors: RH
authors: Schiestl
mesh_terms: D000818:Animals; D002470:Cell Survival; D003092:Colitis / Q000139:chemically induced; D020552:Comet Assay; D004249:DNA Damage; D004195:Disease Models, Animal; D004338:Drug Combinations; D007249:Inflammation / Q000235:genetics / Q000473:pathology*; D016753:Interleukin-10 / Q000008:administration & dosage; D053583:Interleukin-1beta / Q000008:administration & dosage / Q000633:toxicity; D007962:Leukocytes / Q000378:metabolism; D051379:Mice; D018345:Mice, Knockout; D018124:Receptors, Tumor Necrosis Factor / Q000235:genetics*; D015398:Signal Transduction; D014409:Tumor Necrosis Factor-alpha / Q000008:administration & dosage*
chemical_list: D004338:Drug Combinations; D053583:Interleukin-1beta; D018124:Receptors, Tumor Necrosis Factor; D014409:Tumor Necrosis Factor-alpha; D016753:Interleukin-10