Acute pancreatitis (AP) is a disease characterized by inflammation. Nuclear factor (NF)-κB, 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-κB translocation to acinar nuclei in tumor necrosis factor (TNF)-⍺-induced AP. We investigated TNF-⍺ induction of Smad proteins, PPAR⍺/γ, and NF-κB by TNF-⍺, and hypothesized that PYY would attenuate this effect.

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

Cellular localization of NF-κB 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-⍺ at 2 hours and PYY reduced it. Array analysis revealed upregulation of NF-κB, PPAR⍺/γ, and Smad3/4 with TNF-⍺. TNF-⍺ stimulated NF-κB activation sevenfold, and binding was enhanced (p < 0.05). PYY reduced NF-κB binding to control levels. PPAR binding increased 51% after TNF-⍺ treatment and was reduced to 33% with PYY. Smad3/4 binding was increased (p < 0.05) above controls with TNF-⍺ and PYY reduced it by 40%.

TNF-⍺ increases early nuclear translocation of the p65 subunit of NF-κB in acinar cells. Exposure to TNF-⍺ activates transcription factors NF-κB, Smad3/4, and PPAR⍺/γ. PYY reduces this activation. Treatment with PYY may have therapeutic potential in improving AP.