An NF-?B-microRNA regulatory network tunes macrophage inflammatory responses.
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ABSTRACT: The innate inflammatory response must be tightly regulated to ensure effective immune protection. NF-?B is a key mediator of the inflammatory response, and its dysregulation has been associated with immune-related malignancies. Here, we describe a miRNA-based regulatory network that enables precise NF-?B activity in mouse macrophages. Elevated miR-155 expression potentiates NF-?B activity in miR-146a-deficient mice, leading to both an overactive acute inflammatory response and chronic inflammation. Enforced miR-155 expression overrides miR-146a-mediated repression of NF-?B activation, thus emphasizing the dominant function of miR-155 in promoting inflammation. Moreover, miR-155-deficient macrophages exhibit a suboptimal inflammatory response when exposed to low levels of inflammatory stimuli. Importantly, we demonstrate a temporal asymmetry between miR-155 and miR-146a expression during macrophage activation, which creates a combined positive and negative feedback network controlling NF-?B activity. This miRNA-based regulatory network enables a robust yet time-limited inflammatory response essential for functional immunity.MicroRNAs (miR) are important regulators of gene transcription, with miR-155 and miR-146a both implicated in macrophage activation. Here the authors show that NF-?B signalling, miR-155 and miR-146a form a complex network of cross-regulations to control gene transcription in macrophages for modulating inflammatory responses.
SUBMITTER: Mann M
PROVIDER: S-EPMC5636846 | biostudies-literature | 2017 Oct
REPOSITORIES: biostudies-literature
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