| First Author | Weinberg EO | Year | 2019 |
| Journal | PLoS One | Volume | 14 |
| Issue | 1 | Pages | e0210827 |
| PubMed ID | 30682073 | Mgi Jnum | J:273274 |
| Mgi Id | MGI:6275883 | Doi | 10.1371/journal.pone.0210827 |
| Citation | Weinberg EO, et al. (2019) IL-33 induction and signaling are controlled by glutaredoxin-1 in mouse macrophages. PLoS One 14(1):e0210827 |
| abstractText | Interleukin (IL)-33 is an interleukin-1 like cytokine that enhances Th2 responses and mediates mucosal immunity and allergic inflammation but the mechanism regulating endogenous IL-33 production are still under investigation. In macrophages, lipopolysaccharide (LPS) administration resulted in marked induction of IL-33 mRNA that was blunted in macrophages from glutaredoxin-1 (Glrx) knockout mice and in RAW264.7 macrophages with Glrx knockdown by siRNA. Glutaredoxin-1 is a small cytosolic thioltransferase that controls a reversible protein thiol modification, S-glutationylation (protein-GSH adducts), thereby regulating redox signaling. In this study, we examined the mechanism of Glrx regulation of endogenous IL-33 induction in macrophages. Glrx knockdown resulted in impaired de-glutathionylation of TRAF6, which is required for TRAF6 activation, and inhibited downstream IKKbeta and NF-kappaB activation. Inhibitors of NF-kappaB suppressed IL-33 induction and chromatin IP sequencing data analysis confirmed that IL-33 is an NF-kappaB-responsive gene. Since TRAF6-NF-kappaB activation is also essential for IL-33 signaling through its receptor, ST2L, we next tested the involvement of Glrx in exogenous IL-33 responses in RAW264.7 cells. Recombinant IL-33 (rIL-33) administration induced IL-33 mRNA expression in RAW264.7 macrophages, and this was inhibited by Glrx knockdown. Interestingly, rIL-33-induced IL-33 protein was identified as the 20 kDa cleaved form whereas LPS-induced IL-33 protein was identified as full-length IL-33, which may be less active than the cleaved form. In a clinically-relevant mouse model of asthma, intra-tracheal cockroach antigen treatment induced Glrx protein in wild type mouse lungs but Glrx induction was attenuated in IL-33 knockout mouse lungs, suggesting that IL-33 may regulate Glrx induction in vivo in response to allergen challenge. In summary, our data reveal a novel mechanism by which Glrx controls both LPS- and IL-33-mediated NF-kappaB activation leading to IL-33 production, and paracrine IL-33 can induce Glrx to further regulate inflammatory reactions. |
