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Altered cell volume regulation in a mouse cell‐model of autosomal recessive polycystic kidney disease
Author(s) -
Fintha Attila,
Komlosi Peter,
Siroky Brian J.,
Yoder Bradley K.,
Bell Phillip Darwin
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.4.a339-c
Subject(s) - cilium , cell , medicine , biology , endocrinology , microbiology and biotechnology , autosomal recessive polycystic kidney disease , polycystic kidney disease , chemistry , kidney , genetics
Dysregulated ciliary function is a central feature in the pathogenesis of autosomal recessive polycystic kidney disease (ARPKD). The Oak Ridge Polycystic Kidney mouse model (orpk) , which lacks a functional primary cilium, have elevated subapical [Ca 2+ ] i , and altered cytoskeleton structure in cortical collecting duct cells. These two findings led us to hypothesize that there might be alterations in cell volume regulation in immortalized collecting duct orpk cilia (−) compared to orpk cells in which Tg737 has been re‐introduced, orpk cilia (+). Orpk (+) or orpk (−) cells were loaded with the red fluorescent dye SNARF, then mixed and cocultured on glass cover slips. With detection of SNARF fluorescence, the orpk (+) and orpk (−) cells could be distinguished for up to 4 days. A reduction in osmolality from 310 mOsm/L to 220 mOsm/L resulted in an initial increase in cell volume, as measured with calcein fluorescence, of ~ 5 % in both cell types followed by a compensatory regulatory cell volume decrease (RVD). The initial rate of RVD was 3.2 times faster in the orpk (−) compared to orpk (+) cells. To assess the role of cytosolic Ca 2+ , cells were loaded with the Ca 2+ chelator BAPTA‐AM (30 μmol/L). This maneuver decreased RVD in orpk (−) cells, and abolished the difference in the rate of RVD between the two cell lines. Prior administration of cytochalasin D (5 μmol/L) increased RVD in orpk (+) to a level that was similar to the RVD response in the orpk (−) cells. Thus cell volume regulation appears to be enhanced in the absence of cilia and this may be the consequence of elevated calcium and/or disrupted cytoskeleton.