Role of PPAR gamma in inflammation and glucose transport in Caco-2 cells

Abstract

Colorectal cancer compromises large bowel and rectum. Approximately 20% of patients with inflammatory bowel disease (IBD) develop colon cancer and this population has twofold increase in mortality. IBD is a chronic inflammatory condition of the gastrointestinal epithelium due to alterations in immune system reactivity. In colorectal colitis-associated tumors and in IBD, there is a disruption in pro- and anti-inflammatory responses and the intestinal mucosa secretes high concentrations of pro-inflammatory cytokines. Inflammatory cytokines can regulate carbohydrate metabolism.Peroxisome proliferator-activated receptor gamma (PPAR³) is a nuclear receptor highly expressed in differentiated epithelial cells of the colon, including in the Caco-2 cell line, which controls the expression of large number of regulatory genes in glucose homeostasis and inflammation.Therefore, the aim of this study is to characterize the effects of a PPAR³ agonist and antagonist on inflammation and on glucose metabolism of the Caco-2 cell line. For this, human epithelial Caco-2 cells will be incubated with 2% dextran sodium sulfate (DSS) and the cells will be treated with PPAR³ agonist (pioglitazone 50 and 300uM) and PPAR³ antagonist (GW9662 5 and 10 uM).The methods to be used are: trans-epithelial electrical resistance to determine cellular permeability; glucose transport assay to check the passage through the epithelial monolayer; multiplex ELISA to measure changes in protein content of glucose transporters and inflammatory markers; real time-PCR to analyze changes in gene expression of glucose transporters and inflammatory markers; flow cytometry to understand any additional effects of PPAR³ on apoptosis and cell-cycle checkpoints.