Localization, function and regulation of the two intestinal fatty acid-binding protein types
Autor: | Daniel Sinnett, Emile Levy, Ernest G. Seidman, Alain Montoudis, Moise Bendayan, Edgard Delvin, Nadia Dubé, Jean-François Beaulieu, Geneviève Mailhot, Daniel Ménard |
---|---|
Rok vydání: | 2009 |
Předmět: |
medicine.medical_specialty
Histology Colon Lipoproteins Immunoelectron microscopy Ileum Biology Fatty Acid-Binding Proteins digestive system Microsomal triglyceride transfer protein Fatty acid-binding protein Jejunum Western blot Epidermal growth factor Internal medicine medicine Humans Molecular Biology medicine.diagnostic_test digestive oral and skin physiology Infant Cell Biology Molecular biology Medical Laboratory Technology Endocrinology medicine.anatomical_structure Organ Specificity Caco-2 biology.protein lipids (amino acids peptides and proteins) Caco-2 Cells |
Zdroj: | Histochemistry and Cell Biology. 132:351-367 |
ISSN: | 1432-119X 0948-6143 |
Popis: | Although intestinal (I) and liver (L) fatty acid binding proteins (FABP) have been widely studied, the physiological significance of the presence of the two FABP forms (I- and L-FABP) in absorptive cells remains unknown as do the differences related to their distribution along the crypt-villus axis, regional expression, ontogeny and regulation in the human intestine. Our morphological experiments supported the expression of I- and L-FABP as early as 13 weeks of gestation. Whereas cytoplasmic immunofluorescence staining of L-FABP was barely detectable in the lower half of the villus and in the crypt epithelial cells, I-FABP was visualized in epithelial cells of the crypt-villus axis in all intestinal segments until the adult period in which the staining was maximized in the upper part of the villus. Immunoelectron microscopy revealed more intense labeling of L-FABP compared with I-FABP, accompanied with a heterogeneous distribution in the cytoplasm, microvilli and basolateral membranes. By western blot analysis, I- and L-FABP at 15 weeks of gestation appeared predominant in jejunum compared with duodenum, ileum, proximal and distal colon. Exploration of the maturation aspect documented a rise in L-FABP in adult tissues. Permanent transfections of Caco-2 cells with I-FABP cDNA resulted in decreased lipid export, apolipoprotein (apo) biogenesis and chylomicron secretion. Additionally, supplementation of Caco-2 with insulin, hydrocortisone and epidermal growth factor differentially modulated the expression of I- and L-FABP, apo B-48 and microsomal triglyceride transfer protein (MTP), emphasizing that these key proteins do not exhibit a parallel modulation. Overall, our findings indicate that the two FABPs display differences in localization, regulation and developmental pattern. |
Databáze: | OpenAIRE |
Externí odkaz: |