Publications (2)5.53 Total impact
-
Article: Overexpression of the reg gene in non-obese diabetic mouse pancreas during active diabetogenesis is restricted to exocrine tissue.
[show abstract] [hide abstract]
ABSTRACT: We demonstrated pancreatic reg gene overexpression in non-obese diabetic (NOD) mice during active diabetogenesis. The aim of this study was to determine in which part of the pancreas (endocrine and/or exocrine) the gene(s) and the protein(s) were expressed and if their localization changed with progression of the disease. In situ hybridization analysis and immunocytochemical studies were carried out on pancreas of female and male NOD mice. Both develop insulitis but diabetes develops only in females and in males only when treated by cyclophosphamide. Our results show that whatever the age, sex, and presence of insulitis and/or diabetes, the expression of reg mRNAs and of the corresponding protein(s) was restricted to exocrine tissue. Moreover, reg remains localized in acinar cells in the two opposite situations of (a) cyclophosphamide-treated males in a prediabetic stage presenting a high level of both insulin and reg mRNAs, and (b) the overtly diabetic females with no insulin but a high level of reg mRNA. These findings suggest that overexpression of the reg gene(s) might represent a defense of the acinar cell against pancreatic aggression.Journal of Histochemistry and Cytochemistry 11/2000; 48(10):1401-10. · 2.72 Impact Factor -
Article: Targeting of CFTR protein is linked to the polarization of human pancreatic duct cells in culture.
[show abstract] [hide abstract]
ABSTRACT: A relationship between targeting of the protein CFTR (Cystic Fibrosis Transmembrane conductance Regulator) and cellular polarization has been observed in various types of epithelial cells. However, there are no reports on this in human exocrine pancreatic cells, which are functionally altered in patients with cystic fibrosis. The expression of CFTR and its targeting to apical plasma membranes was investigated during growth and polarization of human ductal pancreatic cancerous Capan-1 cells. Despite their neoplastic origin, the cancerous pancreatic duct cells of the Capan-1 line secrete Cl- and HCO3- ions. We showed by electron microscopy, impregnation of cells with tannin and freeze-fracture that these cells become polarized during growth in culture, and are joined by tight junctions. The expression of CFTR and the various stages in its anchorage to membranes was followed using a specific polyclonal antibody, ECL-885, directed against a synthetic peptide mimicking one of the extracellular loops of CFTR. Qualitative and quantitative confocal microscopic studies showed that: (i) the expression of CFTR was constant during growth, irrespective of cellular conformation, (ii) the number of cells presenting CFTR anchored to membranes increased with time in culture, (iii) the rise in membrane-bound CFTR-immunoreactivity accompanied the polarization of the cells, (iv) CFTR anchored to plasma membranes was distributed regularly over the surface of non-polarized cells, but was localized only at the apical membranes of the polarized cells. Moreover, patch-clamp studies indicated the presence of few Cl- cAMP-dependent conductance CFTR channels on unpolarized cells, and a larger number of CFTR channels on the apical plasma membranes of polarized cells. These results indicated that the anchorage of a functional CFTR to the plasma membrane is progressive and occurs in step with polarization of these human pancreatic duct cells in culture. We suggest that the targeting of CFTR to the apical membranes is directly linked to the process of cellular polarization.European Journal of Cell Biology 08/1998; 76(3):220-7. · 2.81 Impact Factor
