Actin-based cytoskeleton regulates a chloride channel and cell volume in a renal cortical collecting duct cell line.

Cyst expansion in autosomal dominant polycystic kidney disease (ADPKD) requires accumulation of fluid into the cyst lumen, which is probably driven by aberrant chloride secretion by the cyst lining epithelium. Extracellular ATP is a potent stimulus for chloride secretion in many epithelial systems, and provides a plausible mechanism for secretion in ADPKD. Therefore the link between polycystin-1 and ATP-stimulated chloride secretion was investigated in the M1 cortical collecting duct cell line. M1 cells were stably transfected with a glucocorticoid-inducible cytoplasmic C-terminal polycystin-1 construct fused to a membrane expression cassette. Induction of fusion protein expression was associated with augmentation of ATP-stimulated transepithelial chloride secretion. After nystatin-induced permeabilization of the basolateral membrane, it was determined that expression of the polycystin fusion protein modulated an ATP-responsive apical chloride conductance. It is concluded that up-regulation of ATP-stimulated chloride secretion might play a significant role in cyst expansion in ADPKD.

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Receptors for natriuretic peptides in a human cortical collecting duct cell line

Kidney International ◽

10.1038/ki.1997.34 ◽

1997 ◽

Vol 51 (1) ◽

pp. 281-287 ◽

Cited By ~ 13

Author(s):

Valerie Millul ◽

Nicole Ardaillou ◽

Sandrine Placier ◽

Béatrice Baudouin ◽

Pierre M. Ronco

Keyword(s):

Cell Line ◽

Natriuretic Peptides ◽

Collecting Duct ◽

Duct Cell ◽

Cortical Collecting Duct

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Activation of the Amiloride-Sensitive Epithelial Sodium Channel by the Serine Protease mCAP1 Expressed in a Mouse Cortical Collecting Duct Cell Line

Journal of the American Society of Nephrology ◽

10.1681/asn.v115828 ◽

2000 ◽

Vol 11 (5) ◽

pp. 828-834

Author(s):

GRÉGOIRE VUAGNIAUX ◽

VÉRONIQUE VALLET ◽

NICOLE FOWLER JAEGER ◽

CORINNE PFISTER ◽

MARCELLE BENS ◽

...

Keyword(s):

Sodium Channel ◽

Cell Line ◽

Serine Protease ◽

Sodium Transport ◽

Serine Proteases ◽

Collecting Duct ◽

Short Circuit ◽

Short Circuit Current ◽

Duct Cell ◽

Cortical Collecting Duct

Abstract. This study examines whether serine proteases can activate the amiloride-sensitive sodium channel (ENaC) in mammalian kidney epithelial cells. The transepithelial sodium transport assessed by amiloride-sensitive short-circuit current appears to be sensitive to aprotinin, a protease inhibitor in a mouse cortical collecting duct cell line (mpkCCDc14). This result indicated that serine proteases may be implicated in the regulation of ENaC-mediated sodium transport. Using degenerated oligonucleotides to a previously isolated serine protease from Xenopus, xCAP1 (channel activating protease), a novel full-length serine protease (mCAP1), has been isolated and characterized. RNA analysis showed a broad pattern of expression in tissues (kidney, lung, colon, and salivary glands) expressing ENaC. Reverse transcription-PCR experiments also showed that mCAP1 was abundantly expressed in proximal tubule cells and was also expressed in intact and cultured collecting duct cells. Coexpression of the Xenopus, rat, or human α-, β-, and γ-ENaC subunits in Xenopus oocytes also showed that mCAP1 induces a significant increase in ENaC-mediated current accompanied by a decrease of channel molecules at the cell surface. It is proposed that this novel mouse channel activating protease may act as a regulator of ENaC within the kidney.

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