Dataset Information

Trovafloxacin enhances lipopolysaccharide-stimulated production of tumor necrosis factor-? by macrophages: role of the DNA damage response.

ABSTRACT: Trovafloxacin (TVX) is a drug that has caused idiosyncratic, drug-induced liver injury (IDILI) in humans. In a murine model of IDILI, otherwise nontoxic doses of TVX and the inflammagen lipopolysaccharide (LPS) interacted to produce pronounced hepatocellular injury. The liver injury depended on a TVX-induced, small but significant prolongation of tumor necrosis factor-? (TNF) appearance in the plasma. The enhancement of TNF expression by TVX was reproduced in vitro in RAW 264.7 murine macrophages (RAW cells) stimulated with LPS. The current study was designed to identify the molecular target of TVX responsible for this response in RAW cells. An in silico analysis suggested a favorable binding profile of TVX to eukaryotic topoisomerase II-? (TopII?), and a cell-free assay revealed that TVX inhibited eukaryotic TopII? activity. Topoisomerase inhibition is known to lead to DNA damage, and TVX increased the DNA damage marker phosphorylated histone 2A.X in RAW cells. Moreover, TVX induced activation of the DNA damage sensor kinases, ataxia telangiectasia mutated (ATM) and Rad3-related (ATR). The ATR inhibitor NU6027 [6-(cyclohexylmethoxy)-5-nitrosopyrimidine-2,4-diamine] prevented the TVX-mediated increases in LPS-induced TNF mRNA and protein release, whereas a selective ATM inhibitor [2-(4-morpholinyl)-6-(1-thianthrenyl)-4H-pyran-4-one (KU55933)] was without effect. TVX prolonged TNF mRNA stability, and this effect was largely attenuated by NU6027. These results suggest that TVX can inhibit eukaryotic topoisomerase, leading to activation of ATR and potentiation of TNF release by macrophages, at least in part through increased mRNA stability. This off-target effect might contribute to the ability of TVX to precipitate IDILI in humans.

SUBMITTER: Poulsen KL

PROVIDER: S-EPMC4056269 | biostudies-literature | 2014 Jul

REPOSITORIES: biostudies-literature

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Trovafloxacin enhances lipopolysaccharide-stimulated production of tumor necrosis factor-α by macrophages: role of the DNA damage response.

Poulsen Kyle L KL Olivero-Verbel Jesus J Beggs Kevin M KM Ganey Patricia E PE Roth Robert A RA

The Journal of pharmacology and experimental therapeutics 20140509 1

Trovafloxacin (TVX) is a drug that has caused idiosyncratic, drug-induced liver injury (IDILI) in humans. In a murine model of IDILI, otherwise nontoxic doses of TVX and the inflammagen lipopolysaccharide (LPS) interacted to produce pronounced hepatocellular injury. The liver injury depended on a TVX-induced, small but significant prolongation of tumor necrosis factor-α (TNF) appearance in the plasma. The enhancement of TNF expression by TVX was reproduced in vitro in RAW 264.7 murine macrophage ...[more]

PMID: 24817034

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Project description:UnlabelledThe HIV-1 accessory protein Vpr displays different activities potentially impacting viral replication, including the arrest of the cell cycle in the G2 phase and the stimulation of apoptosis and DNA damage response pathways. Vpr also modulates cytokine production by infected cells, but this property remains partly characterized. Here, we investigated the effect of Vpr on the production of the proinflammatory cytokine tumor necrosis factor (TNF). We report that Vpr significantly increases TNF secretion by infected lymphocytes. De novo production of Vpr is required for this effect. Vpr mutants known to be defective for G2 cell cycle arrest induce lower levels of TNF secretion, suggesting a link between these two functions. Silencing experiments and the use of chemical inhibitors further implicated the cellular proteins DDB1 and TAK1 in this activity of Vpr. TNF secreted by HIV-1-infected cells triggers NF-?B activity in bystander cells and allows viral reactivation in a model of latently infected cells. Thus, the stimulation of the proinflammatory pathway by Vpr may impact HIV-1 replication in vivo.ImportanceThe role of the HIV-1 accessory protein Vpr remains only partially characterized. This protein is important for viral pathogenesis in infected individuals but is dispensable for viral replication in most cell culture systems. Some of the functions described for Vpr remain controversial. In particular, it remains unclear whether Vpr promotes or instead prevents proinflammatory and antiviral immune responses. In this report, we show that Vpr promotes the release of TNF, a proinflammatory cytokine associated with rapid disease progression. Using Vpr mutants or inhibiting selected cellular genes, we show that the cellular proteins DDB1 and TAK1 are involved in the release of TNF by HIV-infected cells. This report provides novel insights into how Vpr manipulates TNF production and helps clarify the role of Vpr in innate immune responses and inflammation.

Project description:To define the pathogenesis of bone marrow (BM) involvement in systemic lupus erythematosus (SLE).Tumor necrosis factor ? (TNF?) levels, cell death, and cellular damage in BM from SLE patients, controls, and mice with pristane-induced lupus were analyzed using a morphometric technique and immunohistochemistry. The pathogenesis of BM abnormalities was studied in wild-type (WT), TNF?(-/-) , Toll-like receptor-deficient (TLR-7(-/-) ), interferon (IFN)-?/?/? receptor-knockout (IFNAR(-/-) ), and B cell-deficient (?mt) mice treated with pristane. Flow cytometry was used to examine TNF? production (by intracellular staining) and plasma cell/plasmablast development. CXCL12 expression was determined by quantitative polymerase chain reaction.BM from SLE patients exhibited striking death of niche and hematopoietic cells associated with TNF? overproduction. BM from mice with a type I IFN-mediated lupus syndrome induced by pristane showed similar abnormalities. TNF? was produced mainly by BM neutrophils, many with phagocytosed nuclear material (lupus erythematosus cells). TNF? production was abolished in pristane-treated TLR-7(-/-) and ?mt mice but was restored in ?mt mice by infusing normal plasma. Pristane-treated WT and IFNAR(-/-) mice developed anemia, BM hypocellularity, and extramedullary hematopoiesis, which were absent in TLR-7(-/-) and TNF?(-/-) mice. Additionally, the expression of CXCL12, which is produced by stromal cells and mediates homing of hematopoietic cells and plasmablasts, was decreased in BM from pristane-treated WT mice but was normal in BM from pristane-treated TNF?(-/-) mice.Although autoantibodies and glomerulonephritis are type I IFN dependent, lupus-associated BM abnormalities were TLR-7 and TNF? driven but type I IFN independent, suggesting that lupus is a disorder of innate immunity in which TLR-7 activation by phagocytosed nuclei causes relentless type I IFN and TNF? production mediating glomerulonephritis and hematologic involvement, respectively.

Dataset Information

Trovafloxacin enhances lipopolysaccharide-stimulated production of tumor necrosis factor-? by macrophages: role of the DNA damage response.

Publications

Trovafloxacin enhances lipopolysaccharide-stimulated production of tumor necrosis factor-α by macrophages: role of the DNA damage response.

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