Abstract
Sustained expression of cytoprotective intestinal epithelial heat shock proteins (Hsps), particularly Hsp27, depends on stimuli derived from bacterial flora. In this study, we examined the role of the bacterial chemotactic peptide fMLP in stimulating colonic epithelial Hsp expression at concentrations encountered in a physiological milieu. Treatment of the polarized human intestinal epithelial cell line Caco2bbe with physiological concentrations of fMLP (10-100 nM) induced expression of Hsp27, but not Hsp72, in a time- and concentration-dependent manner. Induction of Hsp27 by fMLP was specific since the fMLP analogs MRP and MLP were not effective. Hsp27 induction by fMLP was blocked by the fMLP-receptor antagonist BOC-FLFLF and was blocked when the dipeptide transporter PepT1, an entry pathway for fMLP, was silenced. fMLP activated both the p38 and ERK1/2 MAP kinase pathways in Caco2bbe cells, but not the SAPK/JNK pathway. The p38 inhibitor SB203580, but not the MEK-1 inhibitor PD98059, blocked Hsp27 induction by fMLP. fMLP treatment inhibited actin depolymerization and decreased transepithelial resistance caused by the oxidant monochloramine, and this inhibition was reversed by silencing Hsp27 expression. fMLP pretreatment also inhibited activation of proinflammatory transcription factor NF-kappaB by TNF-alpha in Caco2bbe cells, reducing induction of NF-kappaB target genes by TNF-alpha both in human intestinal biopsies and Caco2bbe cells. In conclusion, fMLP may contribute to the maintenance of intestinal homeostasis by mediating physiological expression of Hsp27, enhancing cellular protection, and negatively regulating the inflammatory response.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
MeSH terms
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Actins / metabolism
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Caco-2 Cells
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Chloramines / pharmacology
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Cytoprotection* / drug effects
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Dose-Response Relationship, Drug
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Electric Impedance
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Epithelial Cells / metabolism
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Female
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HSP27 Heat-Shock Proteins
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Heat-Shock Proteins / biosynthesis*
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Heat-Shock Proteins / genetics
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Humans
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Interleukin-8 / biosynthesis
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Interleukin-8 / genetics
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Intestinal Mucosa / drug effects
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Intestinal Mucosa / metabolism*
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Intestinal Mucosa / pathology
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MAP Kinase Signaling System
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Male
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Middle Aged
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Molecular Chaperones
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N-Formylmethionine Leucyl-Phenylalanine / metabolism*
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N-Formylmethionine Leucyl-Phenylalanine / pharmacology
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NF-kappa B / metabolism*
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Neoplasm Proteins / biosynthesis*
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Neoplasm Proteins / genetics
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Oligopeptides / pharmacology
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Peptide Transporter 1
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Protein Kinase Inhibitors / pharmacology
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RNA Interference
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RNA, Messenger / biosynthesis
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RNA, Small Interfering / genetics
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RNA, Small Interfering / metabolism
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Receptors, Formyl Peptide / metabolism
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Symporters / metabolism
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Time Factors
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Tissue Culture Techniques
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Transcription, Genetic* / drug effects
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Tumor Necrosis Factor-alpha / biosynthesis
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Tumor Necrosis Factor-alpha / genetics
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Up-Regulation
Substances
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Actins
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Chloramines
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HSP27 Heat-Shock Proteins
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HSPB1 protein, human
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Heat-Shock Proteins
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Interleukin-8
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Molecular Chaperones
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NF-kappa B
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Neoplasm Proteins
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Oligopeptides
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Peptide Transporter 1
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Protein Kinase Inhibitors
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RNA, Messenger
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RNA, Small Interfering
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Receptors, Formyl Peptide
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SLC15A1 protein, human
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Symporters
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Tumor Necrosis Factor-alpha
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tert-butyloxycarbonyl-phenylalanyl-leucyl-phenylalanyl-leucyl-phenylalanyl-OH
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N-Formylmethionine Leucyl-Phenylalanine
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chloramine