Dataset Information

Switching of the relative dominance between feedback mechanisms in lipopolysaccharide-induced NF-?B signaling.

ABSTRACT: A fundamental goal in biology is to gain a quantitative understanding of how appropriate cell responses are achieved amid conflicting signals that work in parallel. Through live, single-cell imaging, we monitored both the dynamics of nuclear factor ?B (NF-?B) signaling and inflammatory cytokine transcription in macrophages exposed to the bacterial product lipopolysaccharide (LPS). Our analysis revealed a previously uncharacterized positive feedback loop involving induction of the expression of Rela, which encodes the RelA (p65) NF-?B subunit. This positive feedback loop rewired the regulatory network when cells were exposed to LPS above a distinct concentration. Paradoxically, this rewiring of NF-?B signaling in macrophages (a myeloid cell type) required the transcription factor Ikaros, which promotes the development of lymphoid cells. Mathematical modeling and experimental validation showed that the RelA positive feedback overcame existing negative feedback loops and enabled cells to discriminate between different concentrations of LPS to mount an effective innate immune response only at higher concentrations. We suggest that this switching in the relative dominance of feedback loops ("feedback dominance switching") may be a general mechanism in immune cells to integrate opposing feedback on a key transcriptional regulator and to set a response threshold for the host.

SUBMITTER: Sung MH

PROVIDER: S-EPMC5381725 | biostudies-literature | 2014 Jan

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Switching of the relative dominance between feedback mechanisms in lipopolysaccharide-induced NF-κB signaling.

Sung Myong-Hee MH Li Ning N Lao Qizong Q Gottschalk Rachel A RA Hager Gordon L GL Fraser Iain D C ID

Science signaling 20140114 308

A fundamental goal in biology is to gain a quantitative understanding of how appropriate cell responses are achieved amid conflicting signals that work in parallel. Through live, single-cell imaging, we monitored both the dynamics of nuclear factor κB (NF-κB) signaling and inflammatory cytokine transcription in macrophages exposed to the bacterial product lipopolysaccharide (LPS). Our analysis revealed a previously uncharacterized positive feedback loop involving induction of the expression of R ...[more]

PMID: 24425788

Similar Datasets

Project description:BackgroundSepsis is a high-mortality disease without effective therapeutic options. The hyperactivation of the monocyte-macrophage system, especially M1 macrophages, triggers the onset of septic shock. Gentiopicroside (GENT), the main active component in the traditional Chinese medicinal herb Radix Gentianae, has been shown to have anti-inflammatory properties. Nevertheless, this anti-inflammatory effect has not been fully elucidated.MethodsIn vitro, we stimulated primary bone marrow-derived macrophages (BMMs) or peritoneal elucidated macrophages (PEMs) by lipopolysaccharide (LPS) and interferon (IFN)-γ and pre-treated with GENT and we tested the cytokines such as interleukin (IL)-1β, IL-6 and tumor necrosis factor (TNF) α production by enzyme linked immunosorbent assay (ELISA) or real-time quantitative PCR (qPCR). Further, we determined the NF-κB-mediated inflammatory pathway such as IKKα/β and p65 phosphorylation by Western blot. Then we detected the p65 nuclear localization by immunofluorescent staining. Moreover, NF-κB inhibitor and p65-targeted siRNAs were further used to validate the anti-inflammatory mechanism of GENT. In vivo, GENT (50 mg/kg) was administered intragastrically before and after LPS (40 mg/kg) injection. The death time were recorded and the serum levels of IL-1β, IL-6 and TNFα were tested by ELISA, and the IL-1β, IL-6 and TNFα mRNA expression in the lung were test by qPCR and the M1 infiltration in the lung were determined by F4/80 and INOS immunofluorescent staining.ResultsIn vitro, we observed that GENT reduced the inflammatory cytokine production of BMMs stimulated by (LPS)/IFN-γ and ameliorated the phosphorylation of IKKα/β and p65, the degradation of IκBα, and the translocation of p65 into the nucleus. We did not find GENT has any effect on MAPK signaling under LPS/IFN-γ stimulation. NF-κB inhibitor and p65 siRNAs eliminated the inhibition effect of GENT. In vivo, we observed GENT prevented mice from dying in the LPS-induced shock model and decreased the serum levels of IL-1β and IL-6, the mRNA expression of IL-1β, IL-6 and TNFα in lung tissue, and the amount of M1 macrophage infiltration in the lung.ConclusionsGENT prevented LPS/IFN-γ-induced inflammatory cytokine production by macrophages through the NF-κB signaling pathway in vitro and protected against the endotoxin shock induced by LPS in vivo.

Dataset Information

Switching of the relative dominance between feedback mechanisms in lipopolysaccharide-induced NF-?B signaling.

Publications

Switching of the relative dominance between feedback mechanisms in lipopolysaccharide-induced NF-κB signaling.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets