Differential regulation of gene expression of neurotensin and prohormone convertases PC1 and PC2 in the bovine ocular ciliary epithelium: possible implications on neurotensin processing.
Prohormone convertases PC1 and PC2 are enzymes involved in the intracellular processing of pro-neurotensin/neuromedin N (pro-NT/NN) through the regulated secretory pathway. In this study, we present evidence of the differential gene expression of pro-NT/NN, pro-PC1 and pro-PC2 in two cell lines established from the neuroendocrine ocular ciliary epithelium. Dexamethasone and forskolin were found to synergistically up-regulate NT/NN mRNA expression in both cell types. The pigmented cells released NT, and this release was enhanced by agents that induced its biosynthesis. In contrast, nonpigmented cells exhibited a significantly reduced neurotensin secretion in response to inducers, leading to an accumulation of the peptide. PC1 and PC2 mRNA expression was induced in a cell-specific manner by the same agents that enhanced pro-NT/NN biosynthesis. These results demonstrate cell-specific processing of pro-NT/NN by the ciliary epithelium.
Ortego
Javier
J
Yale University School of Medicine, Department of Ophthalmology and Visual Science, 330 Cedar Street, New Haven, CT 06510, USA.
Wollmann
Guido
G
Coca-Prados
Miguel
M
D000818:Animals; D016282:Aspartic Acid Endopeptidases / Q000096:biosynthesis*; D002417:Cattle; D002460:Cell Line; D002924:Ciliary Body / Q000166:cytology / Q000201:enzymology / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000502:physiology*; D009496:Neurotensin / Q000096:biosynthesis*; D010857:Pigment Epithelium of Eye / Q000166:cytology / Q000201:enzymology / Q000378:metabolism*; D045706:Proprotein Convertase 2; D043484:Proprotein Convertases; D013381:Subtilisins / Q000096:biosynthesis*
D009496:Neurotensin; D043484:Proprotein Convertases; D013381:Subtilisins; D045706:Proprotein Convertase 2; D016282:Aspartic Acid Endopeptidases