fura-ffp18 has been researched along with Polycystic-Kidney--Autosomal-Dominant* in 1 studies
1 other study(ies) available for fura-ffp18 and Polycystic-Kidney--Autosomal-Dominant
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Loss of primary cilia results in deregulated and unabated apical calcium entry in ARPKD collecting duct cells.
Recent genetic analysis has identified a pivotal role of primary cilia in the pathogenesis of polycystic kidney disease (PKD). However, little is known regarding how cilia loss/dysfunction contributes to cyst development. In epithelial cells, changes in apical fluid flow induce cilia-mediated Ca2+ entry via polycystin-2 (PC2), a cation channel. The Oak Ridge Polycystic Kidney (orpk) mouse contains a mutated Tg737 gene that disrupts expression of polaris, a protein required for ciliogenesis. These studies examine the effect of cilia malformation on Ca2+ entry in orpk cilia(-) collecting duct principal cells, and in orpk cells in which wild-type Tg737 was reintroduced, orpk cilia(+). [Ca2+]i was monitored in confluent cell monolayers using fluorescence microscopy. Intrinsic apical Ca2+ entry was measured by Mn2+ quenching and Ca2+ depletion/readdition under flow conditions below the threshold for stimulation. We found that unstimulated apical Ca2+ entry was markedly increased in cilia(-) cells and was sensitive to Gd3+, an inhibitor of PC2. Electrophysiological measurements demonstrate increased abundance of an apical channel, consistent with PC2, in cilia(-) cells. Immunofluorescence studies revealed that PC2, normally expressed on and at the base of cilia in orpk cilia(+) cells, was observed throughout the apical membrane in cilia(-) cells. Furthermore, cilia(-) cells displayed elevated subapical Ca2+ levels measured with the near-membrane Ca2+ indicator FFP-18. We propose that cilia exert a tonic regulatory influence on apical Ca2+ entry, and absence of cilia results in loss of spatial organization of PC2, causing unregulated Ca2+ entry and elevations in subapical [Ca2+], a factor which may contribute to cyst formation. Topics: Animals; Calcium; Cell Membrane Permeability; Cells, Cultured; Cilia; Fluorescent Antibody Technique; Fluorescent Dyes; Fura-2; Gadolinium; Kidney Tubules, Collecting; Manganese; Mice; Polycystic Kidney, Autosomal Dominant; TRPP Cation Channels; Tumor Suppressor Proteins | 2006 |