Differential Expression of Peroxisome Proliferator-activated Receptors (PPARs) in the Developing Human Fetal Digestive Tract

Abstract

SUMMARY We investigated the spatiotemporal distributions of the different peroxisome proliferator-activated receptor (PPAR) isotypes (α, β, and α) during development (Week 7 to Week 22 of gestation) of the human fetal digestive tract by immunohistochemistry using specific polyclonal antibodies. The PPAR subtypes, including PPARα, are expressed as early as 7 weeks of development in cell types of endodermal and mesodermal origin. The presence of PPARα was also found by Western blotting and nuclease-S1 protection assay, confirming that this subtype is not adipocyte-specific. PPARα, PPARβ, and PPARα exhibit different patterns of expression during morphogenesis of the digestive tract. Whatever the stage and the gut region (except the stomach) examined, PPARα is expressed at a high level, suggesting some fundamental role for this receptor in development and/or physiology of the human digestive tract.

PPARgamma inhibits GH synthesis and secretion and increases apoptosis of pituitary GH-secreting adenomas

“…Peroxisome proliferator-activated receptor (PPAR) g is a ligand-dependent transcription factor belonging to the nuclear receptor superfamily (16); it is highly expressed in adipose tissue, where it plays a key role in the regulation of adipocyte differentiation and fat metabolism (17,18), and in colonic mucosa, where it exerts important functions in the differentiation process (19,20). It is a functional receptor for the thiazolidinedione (TZDs) class of antidiabetic drugs and may function as a tumor-suppressor gene (21,22); its activation has been reported to induce differentiation of liposarcoma (23), prostate cancer (24) or several transformed cells (19,25).…”

Role of endogenous and exogenous ligands for the peroxisome proliferators activated receptors alpha (PPAR-α) in the development of inflammatory bowel disease in mice

“…12 PPARs are expressed in the intestine at various levels. [13][14][15] Recently, it has been also demonstrated that PPAR-a is also expressed in the digestive tract mainly localized in the intestinal mucosa in the small intestine and in the colon. [13][14][15] In particular, it has been demonstrated that there is a higher expression of PPAR in the more differentiated colonic epithelial cells facing the intestinal lumen as compared to cells in the lower parts of the crypts.…”

“…[13][14][15] Recently, it has been also demonstrated that PPAR-a is also expressed in the digestive tract mainly localized in the intestinal mucosa in the small intestine and in the colon. [13][14][15] In particular, it has been demonstrated that there is a higher expression of PPAR in the more differentiated colonic epithelial cells facing the intestinal lumen as compared to cells in the lower parts of the crypts. 13 PPAR-a binds to a diverse set of ligands, namely, arachidonic acid metabolites (prostaglandins and leukotrienes) and plasticizers and synthetic fibrate drugs including clofibrate, fenofibrate and bezafibrate.…”

Propionate Promotes Fatty Acid Oxidation through the Up-Regulation of Peroxisome Proliferator-Activated Receptor α in Intestinal Epithelial Cells

“…PPARa is expressed mainly in brown adipose and liver, but is also expressed in the intestine (14,15). The biology of PPARa in the intestine remains poorly defined, although lipid metabolism in the intestine profoundly affects systemic energy homeostasis (11,12).…”

“…One of them, PPARa, is highly expressed by brown adipose tissue, liver, kidney, heart, and skeletal muscle. Emerging evidence indicates that PPARa is also expressed in the digestive tract and engages in several physiological events such as intestinal permeability and immune response (14)(15)(16)(17). However, no evidence related to the exact biological role of PPARa exists in the intestinal lipid metabolism.…”