PPARγ regulates exocrine pancreas lipase.
Pancreatic lipase (triacylglycerol lipase EC 3.1.1.3) is an essential enzyme in hydrolysis of dietary fat. Dietary fat, especially polyunsaturated fatty acids (PUFA), regulate pancreatic lipase (PNLIP); however, the molecular mechanism underlying this regulation is mostly unknown. As PUFA are known to regulate expression of proliferator-activated receptor gamma (PPARγ), and as we identified in-silico putative PPARγ binding sites within the putative PNLIP promoter sequence, we hypothesized that PUFA regulation of PNLIP might be mediated by PPARγ.



We used in silico bioinformatics tools, reporter luciferase assay, PPARγ agonists and antagonists, PPARγ overexpression in exocrine pancreas AR42J and primary cells to study PPARγ regulation of PNLIP.



Using in silico bioinformatics tools we mapped PPARγ binding sites (PPRE) to the putative promoter region of PNLIP. Reporter luciferase assay in AR42J rat exocrine pancreas acinar cells transfected with various constructs of the putative PNLIP promoter showed that PNLIP transcription is significantly enhanced by PPARγ dose-dependently, reaching maximal levels with multi PPRE sites. This effect was significantly augmented in the presence of PPARγ agonists and reduced by PPARγ antagonists or mutagenesis abrogating PPRE sites. Over-expression of PPARγ significantly elevated PNLIP transcript and protein levels in AR42J cells and in primary pancreas cells. Moreover, PNLIP expression was up-regulated by PPARγ agonists (pioglitazone and 15dPGJ2) and significantly down-regulated by PPARγ antagonists in non-transfected rat exocrine pancreas AR42J cell line cells.



PPARγ transcriptionally regulates PNLIP gene expression. This transcript regulation resolves part of the missing link between dietary PUFA direct regulation of PNLIP.
Department of Nutrition, Faculty of Health Science, Ariel University, Israel.
Hila
H
Danino
Department of Biotechnology Engineering, Ben-Gurion University, Israel.
Ronny Peri-
RP
Naor
Department of Nutrition, Faculty of Health Science, Ariel University, Israel.
Chen
C
Fogel
Department of Nutrition, Faculty of Health Science, Ariel University, Israel.
Yael
Y
Ben-Harosh
Faculty of Health Sciences, Ben Gurion University, Beer Sheva, Israel.
Rotem
R
Kadir
Department of Nutrition, Faculty of Health Science, Ariel University, Israel.
Hagit
H
Salem
Department of Nutrition, Faculty of Health Science, Ariel University, Israel. Electronic address: ruthb@ariel.ac.il.
Ruth
R
Birk
D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D002460:Cell Line; D019295:Computational Biology / Q000379:methods; D015536:Down-Regulation / Q000187:drug effects / Q000235:genetics; D015870:Gene Expression / Q000187:drug effects / Q000235:genetics; D008049:Lipase / Q000235:genetics* / Q000378:metabolism*; D047495:PPAR gamma / Q000235:genetics* / Q000378:metabolism*; D010179:Pancreas / Q000187:drug effects / Q000378:metabolism*; D046790:Pancreas, Exocrine / Q000187:drug effects / Q000378:metabolism*; D000077205:Pioglitazone; D011401:Promoter Regions, Genetic / Q000187:drug effects / Q000235:genetics; D015230:Prostaglandin D2 / Q000031:analogs & derivatives / Q000494:pharmacology; D051381:Rats; D016415:Sequence Alignment; D045162:Thiazolidinediones / Q000494:pharmacology; D014158:Transcription, Genetic / Q000187:drug effects / Q000235:genetics; D015533:Transcriptional Activation / Q000187:drug effects / Q000235:genetics; D015854:Up-Regulation / Q000187:drug effects / Q000235:genetics
C477819:15-deoxyprostaglandin J2; D047495:PPAR gamma; C000613696:PPAR gamma, rat; D045162:Thiazolidinediones; D008049:Lipase; D015230:Prostaglandin D2; D000077205:Pioglitazone
Exocrine pancreas; PPARγ; Pancreatic lipase; Polyunsaturated fatty acids