Characterization of a long-term rat mTAL cell line.
A medullary thick ascending limb (mTAL) cell line, termed raTAL, has been established from freshly isolated rat mTAL tubules and cultured continuously for up to 75 passages; it retains characteristics of mTAL cells even after retrieval from storage in liquid nitrogen for several months. The cells express Tamm-Horsfall glycoprotein (THP), a TAL-specific marker, grow to confluence, exhibit a polygonal morphology characteristic of epithelial cells, and form "domes." Detection of THP, Na(+)-K(+)-2Cl(-) cotransporter (NKCC2), Na(+)-K(+)-ATPase, and renal outer medullary K(+) channel (ROMK) was achieved using indirect immunofluorescence and confocal microscopy. Western blot analysis of NKCC2 expression using two different antibodies revealed a band of approximately 160 kDa, and RT-PCR analysis demonstrated the presence of NKCC2 isoforms A and F, which was confirmed by DNA sequencing; transport of Cl(-) into raTAL cells was inhibited by furosemide. Ouabain- and bumetanide-sensitive oxygen consumption, an index of ion transport activity in the mTAL, was observed in raTAL cells, and the number of domes present was reduced significantly when cells were incubated in the presence of ouabain or bumetanide. The specific activity of Na(+)-K(+)-ATPase activity was determined in raTAL cells (0.67 +/- 0.18 nmol P(i).microg protein(-1).min(-1)), primary cultures of mTAL cells (0.39 +/- 0.08 nmol P(i).microg protein(-1).min(-1)), and freshly isolated mTAL tubules (1.10 +/- 0.29 nmol P(i).microg protein(-1).min(-1)), and approximately 30-50% of total cellular ATPase activity was inhibited by ouabain, in accord with other mTAL preparations. This cell line will be used in studies that address biochemical, molecular, and physiological mechanisms in the mTAL.
Eng
Ben
B
Department of Pharmacology, New York Medical College, Valhalla, NY 10595, USA.
Mukhopadhyay
Somshuvra
S
Vio
Carlos P
CP
Pedraza
Paulina L
PL
Hao
Shoujin
S
Battula
Sailaja
S
Sehgal
Pravin B
PB
McGiff
John C
JC
Ferreri
Nicholas R
NR
D000818:Animals; D002460:Cell Line / Q000502:physiology*; D002712:Chlorides / Q000378:metabolism; D004847:Epithelial Cells / Q000166:cytology / Q000378:metabolism; D007679:Kidney Medulla / Q000166:cytology* / Q000378:metabolism*; D008138:Loop of Henle / Q000166:cytology* / Q000378:metabolism*; D008297:Male; D009088:Mucoproteins / Q000378:metabolism; D010101:Oxygen Consumption / Q000502:physiology; D024661:Potassium Channels, Inwardly Rectifying / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D028021:Sodium-Potassium-Chloride Symporters / Q000378:metabolism; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism; D064466:Solute Carrier Family 12, Member 1; D058949:Uromodulin
D002712:Chlorides; D009088:Mucoproteins; D024661:Potassium Channels, Inwardly Rectifying; C578716:Slc12a1 protein, rat; D028021:Sodium-Potassium-Chloride Symporters; D064466:Solute Carrier Family 12, Member 1; C548614:Umod protein, rat; D058949:Uromodulin; D000254:Sodium-Potassium-Exchanging ATPase