A 13C-NMR study on the influxes into the tricarboxylic acid cycle of a renal epithelial cell line, LLC-PK1/Cl4: the metabolism of [2-13C]glycine, l-[3-13C]alanine and l-[3-13C]aspartic acid in renal epithelial cells

1988 ◽  
Vol 970 (3) ◽  
pp. 241-250 ◽  
Author(s):  
Arnold W.H. Jans ◽  
Dieter Leibfritz
1999 ◽  
Vol 342 (3) ◽  
pp. 555 ◽  
Author(s):  
Sylvie DUGELAY ◽  
Marie-France CHAUVIN ◽  
Frédérique MEGNIN-CHANET ◽  
Guy MARTIN ◽  
Marie-Catherine LARÉAL ◽  
...  

1992 ◽  
Vol 20 (2) ◽  
pp. 218-221
Author(s):  
Henning F. Bjerregaard

An established epithelial cell line (A6) from a South African clawed toad (Xenopus laevis) kidney was used as a model for the corneal epithelium of the eye in order to determine ocular irritancy. When grown on Millipore filter inserts, A6 cells form a monolayer epithelium of high electrical resistance and generate a trans-epithelial potential difference. These two easily-measured electrophysiological endpoints showed a dose-related decrease after exposure for 24 hours to seven selected chemicals of different ocular irritancy potential. It was demonstrated that both trans-epithelial resistance and potential ranked closely with in vivo eye irritancy data and correlated well (r = 0.96) with loss of trans-epithelial impermeability of Madin-Darby canine kidney (MDCK) cells, detected by use of a fluorescein leakage assay.


Endocrinology ◽  
2003 ◽  
Vol 144 (5) ◽  
pp. 1825-1831 ◽  
Author(s):  
Mika Matsushita ◽  
Masayoshi Shichiri ◽  
Nozomi Fukai ◽  
Naoko Ozawa ◽  
Takanobu Yoshimoto ◽  
...  

Urotensin-II (UII), a cyclic dodecapeptide with potent cardiovascular effects, has recently been shown to be abundantly expressed in the human kidney and excreted in human urine. To investigate whether UII acts as an autocrine/paracrine growth factor for renal epithelial cells, we have studied the effects of human UII (hUII) on DNA synthesis, cytosolic free Ca2+ concentration ([Ca2+]i), ERK activation, and protooncogene (c-myc) expression in a porcine renal epithelial cell line (LLCPK1). hUII stimulated [3H]thymidine uptake into quiescent cells in a dose-dependent manner (10−9 to 10−7m); this effect was inhibited by a protein kinase C inhibitor (GF109203X), a MAPK kinase inhibitor (PD98059), and a calcium channel blocker (nicardipine). Neither phosphatidyl inositol-3 kinase inhibitors (LY294002, wortmannin) nor p38 kinase inhibitor (SB203580) affected the hUII-induced DNA syntheses. hUII rapidly (within 5 min) and dose-dependently (10−9 to 10−7m) increased [Ca2+]i in fura-2-loaded cells. hUII also caused a rapid and transient activation of ERK1/2 and induction of c-myc. LLCPK1 cells expressed UII mRNA and its receptor GPR14 mRNA, as determined by RT-PCR, and released UII-like immunoreactivity into media. Neutralization of endogenous UII by anti-hUII antibody, but not nonimmune serum, significantly suppressed DNA synthesis. These data suggest that hUII is an autocrine/paracrine growth factor for renal epithelial cells via activation of both protein kinase C and ERK1/2 pathways as well as Ca2+ influx via voltage-dependent Ca2+ channels.


1992 ◽  
Vol 284 (3) ◽  
pp. 725-732 ◽  
Author(s):  
A S Pollock ◽  
D H Lovett

We used an enhancerless U3 mutant retroviral vector to deliver chimeras of the phosphoenolpyruvate carboxykinase (PEPCK) promoter region to a renal epithelial cell line capable of expressing PEPCK mRNA. Chimeras consisting of the PEPCK promoter and chloramphenicol acetyltransferase, neomycin phosphotransferase or human growth hormone genes were expressed after viral infection of the NRK52E renal epithelial cell line. Virus-delivered sequences in which the direction of PEPCK promoter transcription was antegrade to the normal direction of the long terminal repeat (LTR)-initiated transcription correctly upon stimulation with dexamethasone or 8-bromo cyclic AMP and upon lowering of the extracellular pH. Fluorescent primer extension in situ using primers specific for virus-delivered sequences of antegrade constructs indicated that a large fraction of NRK52E cells could be infected by co-cultivation with virus-producing psi-2 cells without G418 selection. Virus-delivered constructs whose orientation was opposite to that of the LTRs were expressed at very low levels, with transcripts detectable by PCR only in RNA from cyclic AMP-treated cells. Using reverse transcription/PCR, we demonstrated that the chimeric transcripts were from the internal PEPCK promoter rather than a functional or reconstituted Moloney LTR. PEPCK-reporter chimeras delivered by retroviral vectors demonstrated a level of expression more consistent with the level of expression of the native PEPCK gene than did transfected chimeras. This expression system should prove useful for studies of the physiological modulation of gene expression in renal tissues.


1990 ◽  
Vol 169 (2) ◽  
pp. 578-584 ◽  
Author(s):  
Kazuki Ohta ◽  
Yukio Hirata ◽  
Taihei Imai ◽  
Kazuo Kanno ◽  
Toshiaki Emori ◽  
...  

1987 ◽  
pp. 115-120
Author(s):  
A. W. H. Jans ◽  
E. Kellenbach ◽  
J. Luiq ◽  
P. Raniewski ◽  
B. Griewel ◽  
...  

2006 ◽  
Vol 290 (2) ◽  
pp. C492-C498 ◽  
Author(s):  
Diego Alvarez de la Rosa ◽  
Ignacio Gimenez ◽  
Biff Forbush ◽  
Cecilia M. Canessa

Serum- and glucocorticoid-induced kinase 1 (SGK1) is thought to be an important regulator of Na+ reabsorption in the kidney. It has been proposed that SGK1 mediates the effects of aldosterone on transepithelial Na+ transport. Previous studies have shown that SGK1 increases Na+ transport and epithelial Na+ channel (ENaC) activity in the apical membrane of renal epithelial cells. SGK1 has also been implicated in the modulation of Na+-K+-ATPase activity, the transporter responsible for basolateral Na+ efflux, although this observation has not been confirmed in renal epithelial cells. We examined Na+-K+-ATPase function in an A6 renal epithelial cell line that expresses SGK1 under the control of a tetracycline-inducible promoter. The results showed that expression of a constitutively active mutant of SGK1 (SGK1 TS425D) increased the transport activity of Na+-K+-ATPase 2.5-fold. The increase in activity was a direct consequence of activation of the pump itself. The onset of Na+-K+-ATPase activation was observed between 6 and 24 h after induction of SGK1 expression, a delay that is significantly longer than that required for activation of ENaC in the same cell line (1 h). SGK1 and aldosterone stimulated the Na+ pump synergistically, indicating that the pathways mediated by these molecules operate independently. This observation was confirmed by demonstrating that aldosterone, but not SGK1 TS425D, induced an ∼2.5-fold increase in total protein and plasma membrane Na+-K+-ATPase α1-subunit abundance. We conclude that aldosterone increases the abundance of Na+-K+-ATPase, whereas SGK1 may activate existing pumps in the membrane in response to chronic or slowly acting stimuli.


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