NOD2-Nitric Oxide-responsive MicroRNA-146a Activates Sonic Hedgehog Signaling to Orchestrate Inflammatory Responses in Murine Model of Inflammatory Bowel Disease

Ghorpade, Devram Sampat and Sinha, Akhuri Yash and Holla, Sahana and Singh, Vikas and Balaji, Kithiganahalli Narayanaswamy (2013) NOD2-Nitric Oxide-responsive MicroRNA-146a Activates Sonic Hedgehog Signaling to Orchestrate Inflammatory Responses in Murine Model of Inflammatory Bowel Disease. In: JOURNAL OF BIOLOGICAL CHEMISTRY, 288 (46). pp. 33037-33048.

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Abstract

Background: Genetic variants of NOD2 are linked to inflammatory bowel disease (IBD) etiology. Results: DSS model of colitis in wild-type and inducible nitric-oxide synthase (iNOS) null mice revealed that NOD2-iNOS/NO-responsive microRNA-146a targets NUMB gene facilitating Sonic hedgehog (SHH) signaling. Conclusion: miR-146a-mediated NOD2-SHH signaling regulates gut inflammation. Significance: Identification of novel regulators of IBD provides new insights into pathophysiology and development of new therapy concepts. Inflammatory bowel disease (IBD) is a debilitating chronic inflammatory disorder of the intestine. The interactions between enteric bacteria and genetic susceptibilities are major contributors of IBD etiology. Although genetic variants with loss or gain of NOD2 functions have been linked to IBD susceptibility, the mechanisms coordinating NOD2 downstream signaling, especially in macrophages, during IBD pathogenesis are not precisely identified. Here, studies utilizing the murine dextran sodium sulfate model of colitis revealed the crucial roles for inducible nitric-oxide synthase (iNOS) in regulating pathophysiology of IBDs. Importantly, stimulation of NOD2 failed to activate Sonic hedgehog (SHH) signaling in iNOS null macrophages, implicating NO mediated cross-talk between NOD2 and SHH signaling. NOD2 signaling up-regulated the expression of a NO-responsive microRNA, miR-146a, that targeted NUMB gene and alleviated the suppression of SHH signaling. In vivo and ex vivo studies confirmed the important roles for miR-146a in amplifying inflammatory responses. Collectively, we have identified new roles for miR-146a that established novel cross-talk between NOD2-SHH signaling during gut inflammation. Potential implications of these observations in therapeutics could increase the possibility of defining and developing better regimes to treat IBD pathophysiology.

Item Type:	Journal Article
Publication:	JOURNAL OF BIOLOGICAL CHEMISTRY
Publisher:	AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC
Additional Information:	Copyright for this article belongs to AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC,USA
Keywords:	Inflammation; Inflammatory Bowel Disease; Innate Immunity; Macrophages; MicroRNA; Nitric Oxide; NOD-like Receptors (NLR); Signal Transduction; Signaling
Department/Centre:	Division of Biological Sciences > Microbiology & Cell Biology
Date Deposited:	23 Jan 2014 05:42
Last Modified:	23 Jan 2014 05:42
URI:	http://eprints.iisc.ac.in/id/eprint/48223

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