Microglia-Secreted Galectin-3 Acts as a Toll-like Receptor 4 Ligand and Contributes to Microglial Activation.

Burguillos MA, Svensson M, Schulte T, Boza-Serrano A, Garcia-Quintanilla A, Kavanagh E, Santiago M, Viceconte N, Oliva-Martin MJ, Osman AM, Salomonsson E, Amar L, Persson A, Blomgren K, Achour A, Englund E, Leffler H, Venero JL, Joseph B, Deierborg T

Cell Reports - (-) - [2015-03-04; online 2015-03-04]

Inflammatory response induced by microglia plays a critical role in the demise of neuronal populations in neuroinflammatory diseases. Although the role of toll-like receptor 4 (TLR4) in microglia's inflammatory response is fully acknowledged, little is known about endogenous ligands that trigger TLR4 activation. Here, we report that galectin-3 (Gal3) released by microglia acts as an endogenous paracrine TLR4 ligand. Gal3-TLR4 interaction was further confirmed in a murine neuroinflammatory model (intranigral lipopolysaccharide [LPS] injection) and in human stroke subjects. Depletion of Gal3 exerted neuroprotective and anti-inflammatory effects following global brain ischemia and in the neuroinflammatory LPS model. These results suggest that Gal3-dependent-TLR4 activation could contribute to sustained microglia activation, prolonging the inflammatory response in the brain.

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PubMed 25753426

DOI 10.1016/j.celrep.2015.02.012

Crossref 10.1016/j.celrep.2015.02.012

S2211-1247(15)00140-0