Broad and direct interaction between TLR and Siglec families of pattern recognition receptors and its regulation by Neu1
- Children's National Medical Center, United States
- Unversity of California, Davis, United States
- University of California, Davis, United States
- St Jude Children's Research Hospital, United States
Abstract
Both pathogen- and tissue damage-associated molecular patterns induce inflammation through toll-like receptors (TLRs), while sialic acid-binding immunoglobulin superfamily lectin receptors (Siglecs) provide negative regulation. Here we report extensive and direct interactions between these pattern recognition receptors. The promiscuous TLR binders were human SIGLEC-5/9 and mouse Siglec-3/E/F. Mouse Siglec-G did not show appreciable binding to any TLRs tested. Correspondingly, Siglece deletion enhanced dendritic cell responses to all microbial TLR ligands tested, while Siglecg deletion did not affect the responses to these ligands. TLR4 activation triggers Neu1 translocation to cell surface to disrupt TLR4:Siglec-E interaction. Conversely, sialidase inhibitor Neu5Gc2en prevented TLR4 ligand-induced disruption of TLR4:Siglec E/F interactions. Absence of Neu1 in hematopoietic cells or systematic treatment with sialidase inhibitor Neu5Gc2en protected mice against endotoxemia. Our data raised an intriguing possibility of a broad repression of TLR function by Siglecs and a sialidase-mediated de-repression that allows positive feedback of TLR activation during infection.
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Animal experimentation: This study was performed in strict accordance with the recommendations in the Guide for the Care and Use of Laboratory Animals of the National Institutes of Health. All of the animals were handled according to approved institutional animal care and use committee (IACUC) protocols (312-13-05) of the The Children's National Medical Center. Every effort was made to minimize suffering
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© 2014, Chen et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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Broad and direct interaction between TLR and Siglec families of pattern recognition receptors and its regulation by Neu1
eLife 3:e04066.
https://doi.org/10.7554/eLife.04066
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