| First Author | Lacroix M | Year | 2015 |
| Journal | J Biol Chem | Volume | 290 |
| Issue | 45 | Pages | 26943-53 |
| PubMed ID | 26363066 | Mgi Jnum | J:226555 |
| Mgi Id | MGI:5697755 | Doi | 10.1074/jbc.M115.682138 |
| Citation | Lacroix M, et al. (2015) Novel Insights into Interleukin 6 (IL-6) Cis- and Trans-signaling Pathways by Differentially Manipulating the Assembly of the IL-6 Signaling Complex. J Biol Chem 290(45):26943-53 |
| abstractText | The IL-6 signaling complex is described as a hexamer, formed by the association of two IL-6.IL-6 receptor (IL-6R).gp130 trimers, with gp130 being the signal transducer inducing cis- and trans-mediated signaling via a membrane-bound or soluble form of the IL-6R, respectively. 25F10 is an anti-mouse IL-6R mAb that binds to both membrane-bound IL-6R and soluble IL-6R with the unique property of specifically inhibiting trans-mediated signaling events. In this study, epitope mapping revealed that 25F10 interacts at site IIb of IL-6R but allows the binding of IL-6 to the IL-6R and the recruitment of gp130, forming a trimer complex. Binding of 25F10 to IL-6R prevented the formation of the hexameric complex obligate for trans-mediated signaling, suggesting that the cis- and trans-modes of IL-6 signaling adopt different mechanisms for receptor complex assembly. To study this phenomenon also in the human system, we developed NI-1201, a mAb that targets, in the human IL-6R sequence, the epitope recognized by 25F10 for mice. Interestingly, NI-1201, however, did not selectively inhibit human IL-6 trans-signaling, although both mAbs produced beneficial outcomes in conditions of exacerbated IL-6 as compared with a site I-directed mAb. These findings shed light on the complexity of IL-6 signaling. First, triggering cis- versus trans-mediated IL-6 signaling occurs via distinctive mechanisms for receptor complex assembly in mice. Second, the formation of the receptor complex leading to cis- and trans-signaling biology in mice and humans is different, and this should be taken into account when developing strategies to inhibit IL-6 clinically. |
