Proteinase-activated receptors induce interleukin-8 expression by intestinal epithelial cells through ERK/RSK90 activation and histone acetylation.
Proteinase-activated receptors (PARs) are involved in both inflammation and tumorigenesis in epithelial cells. Interleukin (IL)-8 is a potent chemoattractant and is also involved in angiogenesis. The molecular mechanism whereby PARs induce epithelial IL-8 expression is not known. In HT-29 colonic epithelial cells, PAR(1) or PAR(2) agonists stimulated the expression of IL-8 through a NF-kappaB-dependent pathway without inducing IkappaB degradation and disassociation of IkappaB from NF-kappaB. Further studies revealed that PAR activation induced the phosphorylation of p65 at Ser-276 in the nucleus, which increased the recruitment of histone acetyltransferase (HAT) p300 to p50. Inhibition of ERK activation completely blocked PAR-induced IL-8 expression, phosphorylation of p65 and HAT activity. We also demonstrated that RSK p90 was the downstream kinase that mediated ERK-induced nuclear p65 phosphorylation. In conclusion, activation of either PAR(1) or PAR(2) stimulated the transcriptional up-regulation of IL-8 in HT-29 colonic epithelial cells through a pathway that involved ERK/RSK p90, NF-kappaB phosphorylation, and HAT activity. These studies provide evidence of a new role for serine proteinases and PARs in the regulation of gene expression in colonic inflammation and tumorigenesis.
Wang
Hongying
H
Inflammation Research Network, University of Calgary, Calgary, AB, Canada.
Moreau
France
F
Hirota
Christina L
CL
MacNaughton
Wallace K
WK
D000107:Acetylation; D015153:Blotting, Western; D002478:Cells, Cultured; D003106:Colon / Q000166:cytology / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D004847:Epithelial Cells / Q000378:metabolism; D005786:Gene Expression Regulation; D051548:Histone Acetyltransferases / Q000235:genetics / Q000378:metabolism; D006657:Histones / Q000378:metabolism*; D006801:Humans; D020672:I-kappa B Proteins / Q000235:genetics / Q000378:metabolism; D047468:Immunoprecipitation; D016209:Interleukin-8 / Q000378:metabolism*; D008156:Luciferases / Q000378:metabolism; D019950:Mitogen-Activated Protein Kinase 1 / Q000235:genetics / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3 / Q000235:genetics / Q000378:metabolism*; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation; D011499:Protein Processing, Post-Translational; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D044463:Receptor, PAR-1 / Q000235:genetics / Q000378:metabolism*; D044464:Receptor, PAR-2 / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D038744:Ribosomal Protein S6 Kinases, 90-kDa / Q000235:genetics / Q000378:metabolism*; D014162:Transfection; D050880:p300-CBP Transcription Factors / Q000235:genetics / Q000378:metabolism
D006657:Histones; D020672:I-kappa B Proteins; D016209:Interleukin-8; D016328:NF-kappa B; C000606204:NFKBIA protein, human; D012333:RNA, Messenger; D044463:Receptor, PAR-1; D044464:Receptor, PAR-2; D000072000:NF-KappaB Inhibitor alpha; D008156:Luciferases; D051548:Histone Acetyltransferases; D050880:p300-CBP Transcription Factors; C069329:RPS6KA1 protein, human; D038744:Ribosomal Protein S6 Kinases, 90-kDa; C069330:ribosomal protein S6 kinase, 90kDa, polypeptide 3; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3