Marshall Digital Scholar

Title

Lipopolysaccharide-induced activation of NF-κB non-canonical pathway requires BCL10 serine 138 and NIK phosphorylations

Authors

Sumit Bhattacharyya
Alip Borthakur, Marshall UniversityFollow
Pradeep K. Dudeja
Joanne K. Tobacman

Document Type

Article

Publication Date

11-15-2010

Abstract

Background and Aims: B-cell lymphoma / leukemia (BCL)-10 and reactive oxygen species mediate two pathways of NF-κB (RelA) activation by lipopolysaccharide (LPS) in human colonic epithelial cells. The pathway for LPS activation of RelB by the non-canonical pathway (RelB) in non-myeloid cells was not yet reported, but important for understanding the range of potential microbial LPS-induced effects in inflammatory bowel disease.

Methods: Experiments were performed in human colonic epithelial cells and in mouse embryonic fibroblasts deficient in components of the IkappaB kinase (IKK) signalosome, in order to detect mediators of the non-canonical pathway of NF-κB activation, including nuclear RelB and p52 and phospho- and total NF-κB inducing kinase (NIK). BCL10 was silenced by siRNA and effects of mutations of specific phosphorylation sites of BCL10 (Ser138Gly and Ser218Gly) were determined.

Results: By the non-canonical pathway, LPS exposure increased nuclear RelB and p52, and phospho-NIK, with no change in total NIK. Phosphorylation of BCL10 Serine 138 was required for NIK phosphorylation, since mutation of this residue eliminated the increases in phospho-NIK and nuclear RelB and p52. Mutations of either Serine 138 or Serine 218 reduced RelA, p50, and phospho-IκBα of the canonical pathway. Effects of LPS stimulation and BCL10 silencing on NIK phosphorylation were demonstrated in confocal images.

Conclusions: LPS-induces activation of both canonical and non-canonical pathways of NF-κB in human colonic epithelial cells, and the non-canonical pathway requires phosphorylations of BCL10 (Serine 138) and NIK. These findings demonstrate the important role of BCL10 in mediating LPS-induced inflammation in human colonic epithelial cells and may open new avenues for therapeutic interventions.

Comments

The version of record is available at https://dx.doi.org/10.1016%2Fj.yexcr.2010.05.004.

Copyright © 2010 Elsevier.

Recommended Citation

Bhattacharyya S, Borthakur A, Dudeja PK, Tobacman JK. Lipopolysaccharide-induced activation of NF-κB non-canonical pathway requires BCL10 serine 138 and NIK phosphorylations. Exp Cell Res. 2010;316(19):3317-27. doi:10.1016/j.yexcr.2010.05.004.