The effect of peroxisome proliferator-activated receptor gamma ligand on signaling pathway in pancreatic acinar calls

Abstract

Objective To investigate the putative relationship between peroxisome proliferators activated receptor gamma (PPARγ) and nuclear factor (NF)-κB in cerulein-treated pancreatic aeinar AR42J cells. Methods The AR42J cells were allocated to control group, pioglitazone group (treated with 40 μmol/L of pioglitazone), pioglitazone + cerulein group (treated with 40 μmol/L of pioglitazone+ 10~(-8) mol/L of cerulein) and pioglitazone + cerulein + PPARγ antagonist (GW9662) group (treated with 40 μmol/L of pioglitazone + 5 μmol/L of GW9662 + 10~(-8) mol/L of cerulein). Activity of NF-κB and PPARγ expression were detected 30 minuts after stimulated by cerulein with or without the presence of pioglitazone. The protein expressions of NF-κB and PPARγ, antibody to IκBα phosphorylation, the differential expression between IκB kinase (IKK)β and IκBa, the IKKβ activity as well as changes of pIκBa were examined by Western blotting. The nuclear accumulation of NF-κB (p65 and p50 subunits) was determined by immunofluorescence and Western blotting. The interaction between NF-κB p65 and IκBα was observed by immunopreeitation. Results Treatment of AR42J cells with pioglitazone attenuated cerulein induced cytosolic activity of IKK protein (1.6 : 3.7)or IκBa phosphorylation (0.9 : 1.5), strengthened the integration of IκBα and NF-κB (0.8:0.3), inhibited transcription activity of p50 and p65 NF-κB dimer and nuclear accumulation (P<0.01). Adversely, the inhibitory effect of pioglitazone on NF-κB activity induced by cerulein was almost reversed by GW9662 (P<0.05). Conclusion These findings provide evidence for the involvement of PPARγ in the activity of NF-κB in cerulein treated AR42J cells. Key words: Inflammation; Cerulein; Nuclear factor-κB; Peroxisome proliferator-activated receptors; Pioglitazone