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This Article Full Text Full Text (PDF) All Versions of this Article: 294/4/F890    most recent 00341.2007v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Rohatgi, R. Articles by Satlin, L. M. Search for Related Content PubMed PubMed Citation Articles by Rohatgi, R. Articles by Satlin, L. M.

Mechanoregulation of intracellular Ca²⁺ in human autosomal recessive polycystic kidney disease cyst-lining renal epithelial cells

Departments of ¹Medicine and ²Pediatrics, The Mount Sinai School of Medicine, New York, New York

Submitted 22 July 2007 ; accepted in final form 1 February 2008

Mutations of cilia-expressed proteins are associated with an attenuated shear-induced increase in intracellular Ca²⁺ concentration ([Ca²⁺]_i) in renal epithelial cell lines derived from murine models of autosomal recessive polycystic kidney disease (ARPKD). We hypothesized that human ARPKD cyst-lining renal epithelial cells also exhibited dysregulated mechanosensation. To test this, conditionally immortalized cell lines derived from human fetal ARPKD cyst-lining (pool and clone 5E) cell lines with low levels of fibrocystin/polyductin expression and age-matched normal collecting tubule [human fetal collecting tubule (HFCT) pool and clone 2C] cell lines were grown in culture, loaded with a Ca²⁺ indicator dye, and subjected to laminar shear. Clonal cell lines were derived from single cells present in pools of cells from cyst-lining and collecting tubules, microdissected from human kidney. Resting and peak [Ca²⁺]_i were similar between ARPKD 5E and pool, and HFCT 2C and pool; however, the flow-induced peak [Ca²⁺]_i was greater in ARPKD 5E (700 ± 87 nM, n = 21) than in HFCT 2C (315 ± 58 nM, n = 12; P < 0.01) cells. ARPKD 5E cells treated with Gd³⁺, an inhibitor of nonselective cation channels, inhibited but did not abolish the shear-induced [Ca²⁺]_i transient. Cilia were 20% shorter in ARPKD than HFCT cells, but no difference in ciliary localization or total cellular expression of polycystin-2, a mechanosenory Gd³⁺-sensitive cation channel, was detected between ARPKD and HFCT cells. The intracellular Ca²⁺ stores were similar between cells. In summary, human ARPKD cells exhibit an exaggerated Gd³⁺-sensitive mechano-induced Ca²⁺ response compared with controls; whether this represents dysregulated polycystin-2 activity in ARPKD cells remains to be explored.

calcium; ion channel; transport; laminar shear stress