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Recombinant W nt3a and W nt5a elicit macrophage cytokine production and tolerization to microbial stimulation via T oll‐like receptor 4
Author(s) -
Yu ChienHsiung,
Nguyen Tam T. K.,
Irvine Katharine M.,
Sweet Matthew J.,
Frazer Ian H.,
Blumenthal Antje
Publication year - 2014
Publication title -
european journal of immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.272
H-Index - 201
eISSN - 1521-4141
pISSN - 0014-2980
DOI - 10.1002/eji.201343959
Subject(s) - biology , stimulation , cytokine , recombinant dna , toll like receptor , receptor , toll , immunology , macrophage , microbiology and biotechnology , endocrinology , innate immune system , biochemistry , gene , in vitro
An increasing number of studies address the roles of W nt proteins in shaping leukocyte functions. Recombinant W nt3a and W nt5a, prototypical activators of β‐ C atenin‑dependent and ‐independent W nt signaling, respectively, are widely used to investigate the effects of W nt proteins on myeloid cell functions. Recent reports describe both proinflammatory and immunemodulatory effects of W nt3a and W nt5a on macrophages, DC s, and microglia. The underlying molecular mechanisms for this divergence are unclear. We show here that recombinant W nt3a‐ and W nt5a‐induced cytokine production from murine C 57 BL /6 macrophages was dependent on TLR 4 and inhibited by P olymyxin B . Similarly, impairment of TLR ‐induced cytokine production upon preexposure to W nt proteins was TLR 4 dependent. The extent of W nt3a‐ and W nt5a‐induced inflammatory gene expression greatly varied between W nt protein lots. We conclude that cytokine responses and TLR tolerization induced by recombinant W nt proteins are likely explained by contaminating TLR 4 agonists, although we cannot fully exclude that W nt proteins have an intrinsic capacity to signal via TLR 4. This study emphasizes the need for careful, independent verification of W nt‐mediated cellular responses.