New methods for maintaining human renal epithelial cells and analyzing their ion transport functions: potential analysis of genetic disease.
OBJECTIVE
New methods are available to immortalize parenchymal cells from exocrine glands and kidney with retention of differentiation. Adaptation of this technology to small, single-donor biopsy material or surgical specimens could provide genetically homogeneous cells for functional analyses and correlation with genetic background and underlying biochemistry. To develop a methodology useful for renal sodium metabolism, epithelial cell line generation was tested in a hypertensive rat model with features similar to salt-sensitive hypertension in humans. This form of hypertension has a large genetic component and is prevalent in African Americans.


METHODS
Protocols were designed to immortalize primary cultures of microdissected proximal tubule epithelial cells from spontaneously hypertensive (SHR) and control, normotensive Wistar-Kyoto (WKY) rats. Immortalization was based on a replication-defective retrovirus coding for SV40 large T-antigen as positive cell cycle regulator. Transport competent cells that grow on porous filters to form confluent monolayers were selected.


RESULTS
Several proximal tubule cell lines have been developed from SHR and WKY rats. The cells retain important differentiated features, such as epithelial polarity, low monolayer conductance, and sodium-succinate cotransport. They are suitable for analyses of electrolyte transport by electrophysiology or imaging of intracellular fluorescent indicator dyes, such as sodium-binding benzofuran isophthalate.


CONCLUSIONS
Feasibility of generating epithelial cell lines from defined renal segments was demonstrated. The cells retain important transport function so that analyses of sodium metabolism and the influence of genetic background on it are possible. The methodology is applicable to human specimens.
Hopfer
U
U
Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, Ohio 44106-4970, USA.
Woost
P G
PG
Jacobberger
J W
JW
Douglas
J G
JG
D000818:Animals; D044383:Black People / Q000235:genetics; D001794:Blood Pressure / Q000235:genetics* / Q000502:physiology; D002460:Cell Line; D004847:Epithelial Cells / Q000502:physiology; D005240:Feasibility Studies; D006801:Humans; D006973:Hypertension / Q000208:ethnology / Q000235:genetics*; D007473:Ion Channels / Q000235:genetics* / Q000502:physiology; D007668:Kidney / Q000166:cytology*; D007687:Kidney Tubules, Proximal / Q000166:cytology; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D012964:Sodium / Q000378:metabolism; D015222:Sodium Channels / Q000235:genetics / Q000502:physiology; D014882:Water-Electrolyte Balance / Q000235:genetics / Q000502:physiology; D001741:Black or African American
D007473:Ion Channels; D015222:Sodium Channels; D012964:Sodium