Bcl10 mediates LPS-induced activation of NF-kappaB and IL-8 in human intestinal epithelial cells.
Lipopolysaccharide (LPS) is recognized as an inducer of the inflammatory response associated with gram-negative sepsis and systemic inflammatory response syndrome. LPS induction proceeds through Toll-like receptor (TLR) in immune cells and intestinal epithelial cells (IEC). This report presents the first identification of Bcl10 (B-cell CLL/lymphoma 10) as a mediator of the LPS-induced activation of IL-8 in human IEC. Bcl10 is a caspase-recruitment domain-containing protein, associated with constitutive activation of NF-kappaB in MALT (mucosa-associated lymphoid tissue) lymphomas. The normal human IEC line NCM460, normal primary human colonocytes, and ex vivo human colonic tissue were exposed to 10 ng/ml of LPS for 2-6 h. Effects on Bcl10, phospho-IkappaBalpha, NF-kappaB, and IL-8 were determined by Western blot, ELISA, immunohistochemistry, and confocal microscopy. Effects of Bcl10 silencing by small-interfering RNA (siRNA), TLR4 blocking antibody, TLR4 silencing by siRNA, and an IL-1 receptor-associated kinase (IRAK)-1/4 inhibitor on LPS-induced activation were examined. Following Bcl10 silencing, LPS-induced increases in NF-kappaB, IkappaBalpha, and IL-8 were significantly reduced (P < 0.001). Increasing concentrations of LPS were associated with higher concentrations of Bcl10 protein when quantified by ELISA, and the association between LPS exposure and increased Bcl10 was also demonstrated by Western blot, immunohistochemistry, and confocal microscopy. Exposure to TLR4 antibody, TLR4 siRNA, or an IRAK-1/4 inhibitor eliminated the LPS-induced increases in Bcl10, NF-kappaB, and IL-8. Identification of Bcl10 as a mediator of LPS-induced activation of NF-kappaB and IL-8 in normal human IEC provides new insight into mechanisms of epithelial inflammation and new opportunities for therapeutic intervention.
Bhattacharyya
Sumit
S
Department of Medicine, University of Illinois at Chicago, Chicago, Illinois, USA.
Borthakur
Alip
A
Pant
Nitika
N
Dudeja
Pradeep K
PK
Tobacman
Joanne K
JK
D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics / Q000378:metabolism*; D000906:Antibodies; D000074018:B-Cell CLL-Lymphoma 10 Protein; D002460:Cell Line; D003106:Colon / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004847:Epithelial Cells / Q000187:drug effects* / Q000378:metabolism; D006801:Humans; D020672:I-kappa B Proteins / Q000378:metabolism; D007249:Inflammation / Q000378:metabolism; D053592:Interleukin-1 Receptor-Associated Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D016209:Interleukin-8 / Q000378:metabolism*; D007413:Intestinal Mucosa / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology*; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B / Q000378:metabolism*; D010766:Phosphorylation; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000378:metabolism; D051197:Toll-Like Receptor 4 / Q000187:drug effects / Q000276:immunology / Q000378:metabolism; D015854:Up-Regulation
D048868:Adaptor Proteins, Signal Transducing; D000906:Antibodies; D000074018:B-Cell CLL-Lymphoma 10 Protein; C118591:BCL10 protein, human; D020672:I-kappa B Proteins; D016209:Interleukin-8; D008070:Lipopolysaccharides; D016328:NF-kappa B; C000606204:NFKBIA protein, human; D047428:Protein Kinase Inhibitors; D034741:RNA, Small Interfering; C495345:TLR4 protein, human; D051197:Toll-Like Receptor 4; C433788:lipopolysaccharide, E. coli O26-B6; D000072000:NF-KappaB Inhibitor alpha; C507768:IRAK1 protein, human; C507773:IRAK4 protein, human; D053592:Interleukin-1 Receptor-Associated Kinases