High-affinity binding of DNA by lactoferrin (LF) is an established phenomenon, but the biologic function of this interaction remains unclear. LF is an abundant breast milk protein (12.5-87.5 mu mol/L) and is resistant to digestion in the infant gut. Regulation of gene expression by LF appears to be a major activity, particularly in modulating immune responses. We hypothesized that LF binding to DNA is a mechanism of gene regulation and aimed to identify the mechanism and physiologic sites of this activity. Our studies focused on two major biologic compartments of DNA: LF binding to proinflammatory bacterial DNA sequences (CpG motifs) in extracellular compartments and LF binding to genomic DNA promoters in the nucleus. LF 0.5 mmol/L inhibited CpG motif-induced nuclear factor-kappa B (NF-kappa B) activation and interleukin (IL)-8 and IL-12 cytokine gene transcription in B cells. Intestinal epithelial cells were unresponsive to CpG motifs. However, significant LF transferred across M cell-like monolayers, specialized epithelial cells that transcytose intact macromolecules to underlying B-cell follicles in the intestine. LF did not activate gene expression by binding to putative response elements in epithelial and lymphoid cells. Nor did LF bind to putative response elements specifically in gel-shift assays. No nuclear localization of LF was detected in green fluorescent protein (GFP) tagging experiments. We conclude that breast milk LF regulates gene expression by binding CpG motifs extracellularly, with follicular B cells in C the infant intestine a likely target.

Mulligan, P., White, N., Monteleone, G., Wang, P., Wilson, J.w., Ohtsuka, Y., et al. (2006). Breast milk lactoferrin regulates gene expression by binding bacterial DNA CpG motifs but not genomic DNA promoters in model intestinal cells. PEDIATRIC RESEARCH, 59(5), 656-661 [10.1203/01.pdr.0000214958.80011.e1].

Breast milk lactoferrin regulates gene expression by binding bacterial DNA CpG motifs but not genomic DNA promoters in model intestinal cells

MONTELEONE, GIOVANNI;
2006-01-01

Abstract

High-affinity binding of DNA by lactoferrin (LF) is an established phenomenon, but the biologic function of this interaction remains unclear. LF is an abundant breast milk protein (12.5-87.5 mu mol/L) and is resistant to digestion in the infant gut. Regulation of gene expression by LF appears to be a major activity, particularly in modulating immune responses. We hypothesized that LF binding to DNA is a mechanism of gene regulation and aimed to identify the mechanism and physiologic sites of this activity. Our studies focused on two major biologic compartments of DNA: LF binding to proinflammatory bacterial DNA sequences (CpG motifs) in extracellular compartments and LF binding to genomic DNA promoters in the nucleus. LF 0.5 mmol/L inhibited CpG motif-induced nuclear factor-kappa B (NF-kappa B) activation and interleukin (IL)-8 and IL-12 cytokine gene transcription in B cells. Intestinal epithelial cells were unresponsive to CpG motifs. However, significant LF transferred across M cell-like monolayers, specialized epithelial cells that transcytose intact macromolecules to underlying B-cell follicles in the intestine. LF did not activate gene expression by binding to putative response elements in epithelial and lymphoid cells. Nor did LF bind to putative response elements specifically in gel-shift assays. No nuclear localization of LF was detected in green fluorescent protein (GFP) tagging experiments. We conclude that breast milk LF regulates gene expression by binding CpG motifs extracellularly, with follicular B cells in C the infant intestine a likely target.
2006
Pubblicato
Rilevanza internazionale
Articolo
Sì, ma tipo non specificato
Settore MED/12 - GASTROENTEROLOGIA
English
bacterial DNA; CpG oligodeoxynucleotide; DNA; immunoglobulin enhancer binding protein; interleukin 12; interleukin 8; lactoferrin; milk protein; animal cell; article; binding affinity; binding site; breast milk; cellular distribution; controlled study; CpG island; gene expression regulation; immunomodulation; intestine cell; intestine epithelium cell; macromolecule; nonhuman; priority journal; promoter region; protein DNA binding; protein motif; transcription regulation; transcytosis; B-Lymphocytes; Base Sequence; Biological Transport, Active; Carrier Proteins; Cell Line; Cytokines; DNA; Female; Gene Expression Regulation; Humans; Intestines; Milk, Human; NF-kappa B; Oligodeoxyribonucleotides; Promoter Regions (Genetics)
Mulligan, P., White, N., Monteleone, G., Wang, P., Wilson, J.w., Ohtsuka, Y., et al. (2006). Breast milk lactoferrin regulates gene expression by binding bacterial DNA CpG motifs but not genomic DNA promoters in model intestinal cells. PEDIATRIC RESEARCH, 59(5), 656-661 [10.1203/01.pdr.0000214958.80011.e1].
Mulligan, P; White, Nrj; Monteleone, G; Wang, P; Wilson, Jw; Ohtsuka, Y; Sanderson, Ir
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2108/39218
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