Department of Pharmacology, New York Medical College, Valhalla, New York 10595
![]() |
ABSTRACT |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
Medullary thick ascending limb (mTAL)
cells in primary culture express the Ca2+-sensing receptor
(CaR), a G protein-coupled receptor that senses changes in
extracellular Ca2+ (Ca synthesis. Moreover, the
response to Ca
tumor necrosis factor; cyclooxygenase-2; kidney
![]() |
INTRODUCTION |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
IN PREVIOUS STUDIES, WE
HAVE identified two pathways of arachidonic acid metabolism in
the rat medullary thick ascending limb (mTAL) that regulate ion
transport in this nephron segment. Each pathway was activated by either
ANG II or Ca2+ and showed a short-term response (15 min) in
which 20-HETE acted and a long-term response (>2-3 h) in which
PGE2 was the principal product (9, 34).
Furthermore, mTAL cells have been shown to synthesize TNF- and
respond to exogenous TNF by expressing cyclooxygenase-2 (COX-2)
(8, 20). After a several-hour latent period, PMA, a PKC
activator, also induced expression of COX-2 in mTAL cells, suggesting a
PKC link to the response. We concluded that short-term regulation of
ion transport in the mTAL occurred in a COX-2-independent manner,
whereas long-term regulation was TNF and COX-2 dependent. These
findings dictated the experimental design of the present study, namely,
to determine the role of TNF production by the mTAL in mediating COX-2
expression in response to stimulation of the Ca2+-sensing
receptor (CaR) and whether PKC contributes to production of TNF by the mTAL.
The mTAL of Henle's loop is the site of action for loop diuretics and
reabsorbs ~25% of filtered NaCl. It also is responsible for the
generation of concentrated or dilute urine during antidiuresis and
water diuresis, respectively. Na+, K+, and
Cl are reabsorbed from the tubular fluid via the
Na+/K+/2Cl
cotransporter on the
apical membrane while K+ is recycled back to the tubular
fluid via apical K+ channels. mTAL cells produce TNF after
challenge with LPS or ANG II (9, 20). This cytokine, which
increases COX-2-mediated PGE2 production, contributes to a
cytokine- and COX-2-dependent mechanism that inhibits 86Rb
uptake in mTAL cells, an in vitro correlate of natriuresis (8). TNF gene transcription involves multiple
cellular-specific signaling factors, including an increase in
intracellular Ca2+ concentrations and PKC activation
(12, 14, 18).
CaRs are expressed in tissues, including the kidney, that are involved
in Ca2+ homeostasis (26, 27). CaRs are G
protein-coupled receptors that transduce Ca
![]() |
METHODS |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
Animals. Male Sprague-Dawley rats (100-110 g; Charles River Lab, Wilmington, MA) were maintained on standard rat chow (Ralston-Purina, Chicago, IL) and given tap water ad libitum.
Reagents.
Tissue culture media was obtained from Life Technologies (Grand Island,
NY). Reagent-grade chemicals and collagenase (type 1A) were from Sigma
(St. Louis, MO). Polyvinylidene difluoride membranes were obtained from
Amersham (Arlington Heights, IL). Reagents for preparation of the
TNF- ELISA kit were purchased from Pharmingen (San Diego, CA).
PGE2 ELISA kits were from Neogen (Lexington, KY). The
neutralizing anti-TNF antibody was purchased from R&D Systems
(Minneapolis, MN). The
-galactosidase enzyme assay system and
luciferase assay kit were from Promega (Madison, WI). The
pGV-B2-TNFprom promoter construct was a generous gift from Dr. Akio
Nakamura (Teikyo University School of Medicine, Tokyo, Japan).
Isolation of mTAL cells.
The isolation and characterization of mTAL cells (~95% purity) were
performed as previously described (6, 20). Briefly, male
Sprague-Dawley rats were anesthetized with an intraperitoneal injection
of pentobarbital sodium (0.65 mg/100 g body wt). The kidneys were
perfused with sterile 0.9% saline via retrograde perfusion of the
aorta and cut along the corticopapillary axis. The inner stripe of the
outer medulla was excised, minced with a sterile blade, and incubated
for 10 min at 37°C in a 0.1% collagenase solution gassed with 95%
oxygen. The suspension was sedimented on ice and mixed with HBSS
containing 2% BSA, and the supernatant containing the crude suspension
of tubules was collected. The collagenase digestion was repeated three
times with the remaining undigested tissue. The combined supernatants
were spun, resuspended in HBSS, and filtered through a 52-µm nylon
mesh membrane (Fisher Scientific, Springfield, NJ). The filtrated
solution was discarded, and the tubules retained on the mesh were
resuspended in HBSS. Then, the solution was centrifuged at 500 rpm for
5 min, the supernatant was aspirated, and the cells were cultured in
1:1 DMEM/Ham's F-12 medium (GIBCO-BRL), 10% FBS (Gemini), 20 ng/ml
epidermal growth factor (Life Technologies), 100 U/ml
streptomycin-penicillin (GIBCO-BRL), 2 mM L-glutamine,
gentamycin sulfate, and 1 µg/ml fungizone (Gemini). After 3 days,
monolayers of cells were 80-90% confluent. The cells were
quiesced for 24 h in RPMI containing 0.42 mM CaCl2 and
0.5% FBS, 2 mM L-glutamine, 100 U/ml
streptomycin-penicillin, MEM nonessential amino acids (GIBCO-BRL), MEM
sodium pyruvate, and 2-mercaptoethanol before their use. In all
experiments, control conditions (i.e., no addition of
CaCl2) reflect that cells were incubated in media containing 0.42 mM Ca2+. This amount of Ca2+
should be added to the amounts used to challenge the cells to obtain
total Ca
Western blot analysis.
The media were removed and cells were washed three times with 1× PBS.
Cells were lysed with 10 mM Tris · HCl, pH 7.5, 1 mM EDTA, and
1% SDS for 5 min on ice. Protein concentrations were determined with a
detergent-compatible protein assay (DC protein assay kit, Bio-Rad).
Thirty micrograms of cell lysate were mixed with an equal volume of 2×
SDS-PAGE loading buffer (100 mM Tris · Cl, pH 6.8, 200 mM
mercaptoethanol, 4% SDS, 0.2% bromophenol blue, and 20% glycerol)
and boiled for 3 min. The proteins in the cell lysates were separated
on a 10% SDS-PAGE gel and transferred to polyvinylidene difluoride
membranes. The membranes were placed in blocking solution containing
5% nonfat dry milk in Tris-buffered saline containing 0.1% Tween 20 at room temperature (RT) for 30 min. Membranes were immunoblotted with
either a rabbit anti-mouse COX-2 polyclonal antibody (Cayman) or
monoclonal anti--actin (clone AC-15; Sigma) for 1 h at RT. The
membranes were then washed three times with Tris-buffered saline
containing 0.1% Tween 20 and incubated with the appropriate
horseradish peroxidase-conjugated secondary antibody (Santa Cruz) for
30 min at RT. Membranes were washed, and enhanced chemiluminescence was
used to evaluate protein expression. The blots were then scanned, and
relative intensities were determined with Image software (National
Institutes of Health), which was calibrated by using an internal
standard (Kodak). The expression of
-actin was used to correct for
variation in sample loading.
PGE2 ELISA. Quiescent mTAL cells were incubated with CaCl2 or poly-L-arginine in RPMI 1640 containing 0.5% serum for varying times, after which the cell-free supernatants were assayed for PGE2 by ELISA (Neogen) according to the manufacturer's protocol.
Measurement of TNF. Primary cultured rat mTAL cells were quiesced overnight in RPMI 1640 containing 0.5% FCS. Cells were challenged with CaCl2 or poly-L-arginine for different times at 37°C and 5% CO2, and TNF levels in supernatants were determined by ELISA (Pharmingen) according to the manufacturer's protocol.
Gene transfection. mTAL cells were cultured to 70-80% confluence. The medium was removed, and cells were placed in 1 ml of serum-free OPTI-MEM medium containing 3 µg/well of either plasmid DNA containing the CaR (a kind gift from Dr. Karin Rodland, University of Oregon) or empty plasmid vector (pcDNA3.1) and 10 µl lipofectamine reagent (Life Technologies) for 4 h at 37°C and 5% CO2. After the transfection period, 1 ml of DMEM/F-12 containing 20% FCS was added, and the cells were incubated overnight at 37°C and 5% CO2. The medium was then removed, and cells were cultured for an additional 12 h in DMEM/F-12 containing 10% FCS. The cells were quiesced overnight in RPMI medium containing 0.5% FCS and then treated with the appropriate reagents for the indicated times; TNF levels in the supernatants were determined by ELISA.
Analysis of Ca-galactosidase in the presence of 10 µl lipofectamine reagent
and 990 µl OPTI-MEM for 4 h at 37°C and 5% CO2.
Luciferase activity was normalized to account for differences in
transfection efficiency by cotransfecting cells with
pact-
-galactosidase-expressing plasmid. Data were expressed as the
increase of luciferase activity/
-galactosidase activity vs. control.
Statistical analysis.
The responses were compared by unpaired Student's t-test or
by a one-way ANOVA followed by the Newman-Kuels test when multiple comparisons were made. Data are presented as means ± SD;
P 0.05 was considered statistically significant.
![]() |
RESULTS |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
Effects of Ca2+ and the CaR agonist
poly-L-arginine on mTAL TNF production.
Increases in PKC activity and intracellular levels of Ca2+
have been associated with an increase in TNF production (7,
13). As activation of the CaR increases PKC activity and
intracellular Ca2+ levels (27), we determined
the effects of CaR stimulation on TNF production by primary cultures of
mTAL cells. Cells exhibited a significant increase in TNF production
that was observed after exposure to 1.0 mM CaCl2 at each of
the time points tested (Fig. 1A). Moreover, TNF production
was maximal after addition of 1.0 mM CaCl2, except
for the 3-h time period in which maximal production was observed after
addition of 1.2 mM CaCl2. Release of TNF into the media was
time dependent and was near maximal by ~6 h after addition of
CaCl2. Challenge with poly-L-arginine, a
CaR-selective agonist, for 9 h also increased TNF production by
mTAL cells (Fig. 1B). These data indicate that TNF
production by mTAL cells was increased on activation of the CaR.
|
Role of the CaR in TNF production in mTAL cells.
The contribution of the CaR to TNF production was further assessed by
overexpressing the receptor in mTAL cells and measuring the response to
Ca
|
Ca-galactosidase construct, which was used to normalize luciferase
expression, had no endogenous luciferase activity (Fig. 3). These data
suggest that transcriptional regulation of the TNF gene in mTAL cells
was observed after activation of the CaR.
|
TNF contributes to Ca2+-mediated
increases in PGE2 production.
Exogenous TNF induces transient increases in COX-2 mRNA accumulation
and protein expression in mTAL cells (8). Thus the contribution of TNF, synthesized by mTAL cells, to increases in PGE2 production after challenge with Ca
|
|
PKC contributes to Ca2+-mediated TNF
production.
Direct activation of PKC enhances TNF production (35), and
activation of the CaR was reported to enhance PKC activity
(4). Thus the role of PKC in Ca2+-mediated TNF
production was determined. Cells were pretreated with varying
concentrations (0.25-1 µM) of bisindolylmaleimide I, a selective
PKC inhibitor (29), for 15 min and then challenged with
1.2 mM CaCl2 for 9 h. Ca
|
PKC regulates PGE2 production and COX-2 protein
expression.
We previously demonstrated that PMA, a direct PKC activator, increased
COX-2 mRNA accumulation, protein expression, and PGE2 production (8). As the CaR activation also enhances PKC
activity (4), COX-2 protein expression and
PGE2 synthesis were evaluated in cells challenged with
Ca2+ in the absence or presence of bisindolylmaleimide I. Analysis of PGE2 levels by ELISA revealed that mTAL cells
produced 52.13 ± 8.7 pg PGE2/µg protein after
challenge with 1.2 mM CaCl2 for 9 h, approximately a
sixfold increase compared with basal levels of PGE2 (Fig.
7). Basal levels of PGE2 were
not affected by bisindolylmaleimide I. However, PGE2
synthesis induced by Ca
|
|
![]() |
DISCUSSION |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
We have demonstrated that mTAL cells in primary culture produced
TNF after activation of the CaR, the first demonstration of what may be
the basis of an important renal mechanism that regulates salt and water
excretion (23, 24). Exposure of cells to CaCl2
enhanced TNF production in a time- and concentration-dependent manner.
Moreover, the CaR-selective agonist poly-L-arginine also increased TNF production, and the response to Ca
The CaR is a G protein-coupled receptor that has three major domains: a
large (613-amino acid) extracellular NH2 terminus, a
250-amino acid domain with seven membrane-spanning segments, and a 222 amino acid cytoplasmic COOH-terminal domain. The extracellular domain has several regions rich in negatively charged amino acids, which could bind Ca2+ and other cationic ligands (3,
4). Expression studies using Xenopus laevis oocytes
injected with bovine parathyroid RNA demonstrated that exposure of
oocytes to Ca
PKC activation was reported to induce TNF production in certain cell types (10, 19). Because activation of the CaR may enhance PKC activity (16), we hypothesized that TNF production in mTAL cells may be increased after CaR activation. Production of TNF in most cell types is low or absent before cellular stimulation. However, diverse extracellular stimuli, including exposure to Ca2+ ionophore, antigen, virus infection, and LPS, can induce TNF gene expression. Several renal cell types can produce TNF, including proximal and mTAL tubular epithelial cells, as well as mesangial cells (1, 15, 20, 38). TNF may subserve several functions in the kidney, including regulation of pathophysiological events associated with inflammatory diseases in the kidney (5, 17, 36). TNF also may contribute to the chronic tubular injury associated with hypercalcemia. These findings suggest a role for TNF in renal physiological/pathophysiological mechanisms and raise the distinct possibility that other cytokines may contribute to a network of effects in the kidney.
Transcriptional regulation of TNF production by Ca2+ was
assessed by transfecting mTAL cells with a rat TNF promoter construct that drives expression of a luciferase reporter gene in the pGV-B2 plasmid. The significant increase in luciferase activity suggests that
increased TNF promoter activity by means of CaR activation contributed,
at least in part, to the increased synthesis of this cytokine.
Transcription of the TNF gene does not require de novo protein
synthesis and depends on the recruitment of transcription factors in a
cell type-specific manner (30). Moreover, TNF gene transcription in T lymphocytes is characterized by formation of distinct enhancer complexes on the TNF promoter in response to different extracellular stimuli. For instance, distinct sets of TNF
promoter elements were required for induction of TNF gene transcription
by T cell receptor activation, Ca2+ influx, or virus
infection (7). Because activation of the CaR may initiate
several signal transduction pathways in a cell type-specific manner, it
is interesting to note that inhibition of PKC activity in mTAL cells
attenuated TNF production. CaR overexpression experiments showed that
the Ca
TNF has been shown to increase COX-2 protein expression in several cell
types. We found that incubation of mTAL cells with rat recombinant TNF
increased PGE2 production by a COX-2-dependent mechanism
(8). Pretreatment of cells with a COX-2 inhibitor prevented TNF-mediated inhibition of 86Rb uptake, an in
vitro correlate of natriuresis. This mechanism also was demonstrated
for endogenous TNF as LPS-induced inhibition of 86Rb uptake
was abolished in the presence of an anti-TNF antibody, suggesting that
TNF produced by the mTAL acted in an autocrine manner to inhibit
86Rb uptake (6). In the present study, a
neutralizing anti-TNF antibody significantly reduced
Ca
![]() |
ACKNOWLEDGEMENTS |
---|
Dr. Ferreri was an Established Investigator of the American Heart Association during completion of this study.
![]() |
FOOTNOTES |
---|
This work was supported by National Heart, Lung, and Blood Institute Grants HL-56423 and PPG-HL-34300 as well as American Heart Association Grant 9740001N.
Address for reprint requests and other correspondence: N. R. Ferreri, Dept. of Pharmacology, New York Medical College, Valhalla, NY 10595 (E-mail: nick_ferreri{at}nymc.edu).
The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
July 16, 2002;10.1152/ajprenal.00108.2002
Received 21 March 2002; accepted in final form 2 July 2002.
![]() |
REFERENCES |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
1.
Baud, L,
Oudinet JP,
Bens M,
Noe L,
Peraldi MN,
Rondeau E,
Etienne J,
and
Ardaillou R.
Production of tumor necrosis factor by rat mesangial cells in response to bacterial lipopolysaccharide.
Kidney Int
35:
1111-1118,
1989[ISI][Medline].
2.
Brown, EM,
Gamba G,
Riccardi D,
Lombardi M,
Butters R,
Kifor O,
Sun A,
Hediger MA,
Lytton J,
and
Hebert SC.
Cloning and characterization of an extracellular Ca2+-sensing receptor from bovine parathyroid.
Nature
366:
575-580,
1993[ISI][Medline].
3.
Brown, EM,
Pollak M,
and
Hebert SC.
The extracellular calcium-sensing receptor: its role in health and disease.
Annu Rev Med
49:
15-29,
1998[ISI][Medline].
4.
Brown, EM,
Vassilev PM,
Quinn S,
and
Hebert SC.
G-protein-coupled, extracellular Ca(2+)-sensing receptor: a versatile regulator of diverse cellular functions.
Vitam Horm
55:
1-71,
1999[ISI][Medline].
5.
Cunningham, PN,
Dyanov HM,
Park P,
Wang J,
Newell KA,
and
Quigg RJ.
Acute renal failure in endotoxemia is caused by TNF acting directly on TNF receptor-1 in kidney.
J Immunol
168:
5817-5823,
2002
6.
Escalante, BA,
Ferreri NR,
Dunn CE,
and
McGiff JC.
Cytokines affect ion transport in primary cultured thick ascending limb of Henle's loop cells.
Am J Physiol Cell Physiol
266:
C1568-C1576,
1994
7.
Falvo, JV,
Uglialoro AM,
Brinkman BM,
Merika M,
Parekh BS,
Tsai EY,
King HC,
Morielli AD,
Peralta EG,
Maniatis T,
Thanos D,
and
Goldfeld AE.
Stimulus-specific assembly of enhancer complexes on the tumor necrosis factor alpha gene promoter.
Mol Cell Biol
20:
2239-2247,
2000
8.
Ferreri, NR,
An SJ,
and
McGiff JC.
Cyclooxygenase-2 expression and function in the medullary thick ascending limb.
Am J Physiol Renal Physiol
277:
F360-F368,
1999
9.
Ferreri, NR,
Escalante BA,
Zhao Y,
An S,
and
McGiff JC.
Angiotensin II induces TNF production by the thick ascending limb: functional implications.
Am J Physiol Renal Physiol
274:
F148-F155,
1998
10.
Foster, GH,
Armstrong CS,
Sakiri R,
and
Tesh VL.
Shiga toxin-induced tumor necrosis factor alpha expression: requirement for toxin enzymatic activity and monocyte protein kinase C and protein tyrosine kinases.
Infect Immun
68:
5183-5189,
2000
11.
Gama, L,
Baxendale-Cox LM,
and
Breitwieser GE.
Ca2+-sensing receptors in intestinal epithelium.
Am J Physiol Cell Physiol
273:
C1168-C1175,
1997
12.
Goldfeld, AE,
McCaffrey PG,
Strominger JL,
and
Rao A.
Identification of a novel cyclosporin-sensitive element in the human tumor necrosis factor alpha gene promoter.
J Exp Med
178:
1365-1379,
1993[Abstract].
13.
Horiguchi, J,
Spriggs D,
Imamura K,
Stone R,
Luebbers R,
and
Kufe D.
Role of arachidonic acid metabolism in transcriptional induction of tumor necrosis factor gene expression by phorbol ester.
Mol Cell Biol
9:
252-258,
1989[ISI][Medline].
14.
Jain, J,
McCaffrey PG,
Miner Z,
Kerppola TK,
Lambert JN,
Verdine GL,
Curran T,
and
Rao A.
The T-cell transcription factor NFATp is a substrate for calcineurin and interacts with Fos and Jun.
Nature
365:
352-355,
1993[ISI][Medline].
15.
Jevnikar, AM,
Brennan DC,
Singer GG,
Heng JE,
Malinski W,
Wuthrich RP,
Glimcher LH,
and
Kelley VER
Stimulated kidney tubular epithelial cells express membrane associated and secreted TNF.
Kidney Int
40:
203-211,
1991[ISI][Medline].
16.
Kifor, O,
Diaz R,
Butters R,
and
Brown EM.
The Ca2+-sensing receptor (CaR) activates phospholipases C, A2, and D in bovine parathyroid and CaR-transfected, human embryonic kidney (HEK293) cells.
J Bone Miner Res
12:
715-725,
1997[ISI][Medline].
17.
Klahr, S,
and
Morrissey JJ.
The role of vasoactive compounds, growth factors and cytokines in the progression of renal disease.
Kidney Int Suppl
75:
S7-S14,
2000[Medline].
18.
Klegeris, A,
Walker DG,
and
McGeer PL.
Interaction of Alzheimer beta-amyloid peptide with the human monocytic cell line THP-1 results in a protein kinase C-dependent secretion of tumor necrosis factor-alpha.
Brain Res
747:
114-121,
1997[ISI][Medline].
19.
Kontny, E,
Ziolkowska M,
Ryzewska A,
and
Maslinski W.
Protein kinase c-dependent pathway is critical for the production of pro-inflammatory cytokines (TNF-alpha, IL-1beta, IL-6).
Cytokine
11:
839-848,
1999[ISI][Medline].
20.
Macica, C,
Escalante BA,
Conners MS,
and
Ferreri NR.
TNF production by the medullary thick ascending limb of Henle's loop.
Kidney Int
46:
113-121,
1994[ISI][Medline].
21.
Nakamura, A,
Johns EJ,
Imaizumi A,
Abe T,
and
Kohsaka T.
Regulation of tumour necrosis factor and interleukin-6 gene transcription by b2-adrenoceptor in the rat astrocytes.
J Neuroimmunol
88:
144-153,
1998[ISI][Medline].
22.
Paulais, M,
Baudouin-Legros M,
and
Teulon J.
Functional evidence for a Ca2+/polyvalent cation sensor in the mouse thick ascending limb.
Am J Physiol Renal Fluid Electrolyte Physiol
271:
F1052-F1060,
1996
23.
Peterson, LN.
Vitamin D-induced chronic hypercalcemia inhibits thick ascending limb NaCl reabsorption in vivo.
Am J Physiol Renal Fluid Electrolyte Physiol
259:
F122-F129,
1990
24.
Peterson, LN,
McKay AJ,
and
Borzecki JS.
Endogenous prostaglandin E2 mediates inhibition of rat thick ascending limb Cl reabsorption in chronic hypercalcemia.
J Clin Invest
91:
2300-2407,
1993.
25.
Riccardi, D,
Hall AE,
Chattopadhyay N,
Xu JZ,
Brown EM,
and
Hebert SC.
Localization of the extracellular Ca2+/polyvalent cation-sensing protein in rat kidney.
Am J Physiol Renal Physiol
274:
F611-F622,
1998
26.
Riccardi, D,
Lee WS,
Lee K,
Segre GV,
Brown EM,
and
Hebert SC.
Localization of the extracellular Ca2+-sensing receptor and PTH/PTHrP receptor in rat kidney.
Am J Physiol Renal Fluid Electrolyte Physiol
271:
F951-F956,
1996
27.
Riccardi, D,
Park J,
Lee W,
Gamba G,
Brown EM,
and
Hebert SC.
Cloning and functional expression of a rat kidney extracellular calcium/polyvalent cation/sensing receptor.
Proc Natl Acad Sci USA
92:
131-135,
1995[Abstract].
28.
Sutton, RA,
and
Dirks JH.
The renal excretion of calcium: a review of micropuncture data.
Can J Physiol Pharmacol
53:
979-988,
1975[ISI][Medline].
29.
Toullec, D,
Pianetti P,
Coste H,
Bellevergue P,
Grand-Perret T,
Ajakane M,
Baudet V,
Boissin P,
Boursier E,
Loriolle F,
Duhamel L,
Charon D,
and
Kirilovsky J.
The bisindolylmaleimide GF 109203X is a potent and selective inhibitor of protein kinase C.
J Biol Chem
266:
15771-15781,
1991
30.
Tsai, EY,
Yie J,
Thanos D,
and
Goldfeld AE.
Cell-type-specific regulation of the human tumor necrosis factor alpha gene in B cells and T cells by NFATp and ATF-2/JUN.
Mol Cell Biol
16:
5232-5244,
1996[Abstract].
31.
Wang, D,
An SJ,
Wang WH,
McGiff JC,
and
Ferreri NR.
CaR-mediated COX-2 expression in primary cultured mTAL cells.
Am J Physiol Renal Physiol
281:
F658-F664,
2001
32.
Wang, D,
McGiff JC,
and
Ferreri NR.
Regulation of cyclooxygenase isoforms in the renal thick ascending limb: effects of extracellular calcium.
J Physiol Pharmacol
51:
587-595,
2000[ISI][Medline].
33.
Wang, WH,
Lu M,
Balazy M,
and
Hebert SC.
Phospholipase A2 is involved in mediating the effect of extracelluar Ca2+ on apical K+ channels in rat TAL.
Am J Physiol Renal Physiol
273:
F421-F429,
1997
34.
Wang, WH,
Lu M,
and
Hebert SC.
Cytochrome P-450 metabolites mediate extracellular Ca2+-induced inhibition of apical K+ channels in the TAL.
Am J Physiol Cell Physiol
271:
C103-C111,
1996
35.
Watanabe, N,
Nakada K,
and
Kobayashi Y.
Processing and release of tumor necrosis factor alpha.
Eur J Biochem
253:
576-582,
1998[Abstract].
36.
Wolfs, TG,
Buurman WA,
van Schadewijk A,
de Vries B,
Daemen MA,
Hiemstra PS,
and
van't Veer C.
In vivo expression of Toll-like receptor 2 and 4 by renal epithelial cells: IFN-gamma and TNF-alpha mediated up-regulation during inflammation.
J Immunol
168:
1286-1293,
2002
37.
Yan, Z,
Yang DC,
Neill R,
and
Jett M.
Production of tumor necrosis factor alpha in human T lymphocytes by staphylococcal enterotoxin B correlates with toxin-induced proliferation and is regulated through protein kinase C.
Infect Immun
67:
6611-6618,
1999
38.
Yard, BA,
Daha MR,
Kooymans-Couthino M,
Bruijn JA,
Paape ME,
Schrama E,
van Es LA,
and
van Der Woude FJ.
IL-1a stimulated TNFa production by cultured human proximal tubular epithelial cells.
Kidney Int
42:
383-389,
1992[ISI][Medline].