Peptide YY attenuates transcription factor activity in tumor necrosis factor-alpha-induced pancreatitis.
BACKGROUND
Acute pancreatitis (AP) is a disease characterized by inflammation. Nuclear factor (NF)-kappaB, Smad proteins, and the steroid hormone family peroxisome proliferator-activated receptors (PPARs) are involved in regulation of gene transcription during the disease process. Peptide YY (PYY), a gastrointestinal hormone, inhibits NF-kappaB translocation to acinar nuclei in tumor necrosis factor (TNF)-alpha-induced AP. We investigated TNF-alpha induction of Smad proteins, PPARalpha/gamma, and NF-kappaB by TNF-alpha, and hypothesized that PYY would attenuate this effect.


METHODS
Rat acinar cells were treated with recombinant TNF-alpha (200 ng/mL). PYY (3 to 36) was added at 500 pM at 30 minutes after TNF-alpha treatment until cell harvest at 2 hours. Western blot analysis and intracellular staining of the p65 subunit of NF-kappaB were performed. NF-kappaB, Smad3/4, and PPARalpha/gamma binding activities were determined by protein/DNA array analysis and verified by electrophoretic-mobility shift assay and densitometry.


RESULTS
Cellular localization of NF-kappaB p65 showed nuclear staining within 2 hours, with controls stained in the cytoplasm. With PYY, p65 stained in the cytoplasm. Nuclear p65 was increased significantly (p < 0.05) by TNF-alpha at 2 hours and PYY reduced it. Array analysis revealed upregulation of NF-kappaB, PPARalpha/gamma, and Smad3/4 with TNF-alpha. TNF-alpha stimulated NF-kappaB activation sevenfold, and binding was enhanced (p < 0.05). PYY reduced NF-kappaB binding to control levels. PPAR binding increased 51% after TNF-alpha treatment and was reduced to 33% with PYY. Smad3/4 binding was increased (p < 0.05) above controls with TNF-alpha and PYY reduced it by 40%.


CONCLUSIONS
TNF-alpha increases early nuclear translocation of the p65 subunit of NF-kappaB in acinar cells. Exposure to TNF-alpha activates transcription factors NF-kappaB, Smad3/4, and PPARalpha/gamma. PYY reduces this activation. Treatment with PYY may have therapeutic potential in improving AP.
Vona-Davis
Linda
L
Department of Surgery, West Virginia University, Morgantown, WV 26506, USA.
Yu
Alice
A
Magabo
Kristine
K
Evans
Tracy
T
Jackson
Barbara
B
Riggs
Dale
D
McFadden
David
D
D000208:Acute Disease; D000818:Animals; D002460:Cell Line; D004268:DNA-Binding Proteins / Q000187:drug effects / Q000235:genetics / Q000276:immunology; D005768:Gastrointestinal Hormones / Q000235:genetics* / Q000276:immunology / Q000494:pharmacology; D023421:Models, Animal; D016328:NF-kappa B / Q000187:drug effects / Q000235:genetics / Q000276:immunology; D010179:Pancreas / Q000187:drug effects / Q000276:immunology; D010195:Pancreatitis / Q000139:chemically induced / Q000235:genetics* / Q000276:immunology; D019894:Peptide YY / Q000235:genetics* / Q000276:immunology / Q000494:pharmacology; D051381:Rats; D018160:Receptors, Cytoplasmic and Nuclear / Q000187:drug effects / Q000235:genetics / Q000276:immunology; D051785:Smad Proteins; D015534:Trans-Activators / Q000187:drug effects / Q000235:genetics / Q000276:immunology; D014157:Transcription Factors / Q000187:drug effects / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D014178:Translocation, Genetic / Q000187:drug effects / Q000235:genetics; D014409:Tumor Necrosis Factor-alpha / Q000009:adverse effects*
D004268:DNA-Binding Proteins; D005768:Gastrointestinal Hormones; D016328:NF-kappa B; D018160:Receptors, Cytoplasmic and Nuclear; D051785:Smad Proteins; D015534:Trans-Activators; D014157:Transcription Factors; D014409:Tumor Necrosis Factor-alpha; D019894:Peptide YY