1 Department of Medicine, Long Island Jewish Medical Center, The Long Island Campus for the Albert Einstein College of Medicine, New Hyde Park, New York 11040; 2 Department of Medicine, Renmin Hospital, Medical College of Wuhan University, Wuhan, Hubei 430060, China; and 3 Department of Medicine, University of Texas Health Science Center, San Antonio, Texas 78284
![]() |
ABSTRACT |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
ANG II has been shown to modulate kidney
cell growth and contribute to the pathobiology of glomerulosclerosis.
Glomerular visceral epithelial cell (GEC) injury or loss is considered
to play a pivotal role in the initiation and progression of
glomerulosclerosis. In the present study, we investigated the effect of
ANG II on GEC apoptosis. Rat GECs were incubated with
increasing doses of ANG II for variable time periods. Apoptosis
was evaluated by cell nucleus staining and DNA fragmentation assay. ANG
II induced GEC apoptosis in a dose- and time-dependent manner.
The proapoptotic effect was attenuated by the ANG II receptor type
1 antagonist losartan or the ANG II receptor type 2 antagonist
PD-123319 and was completely blocked by incubation with the combined
antagonists. Moreover, ANG II stimulated transforming growth factor
(TGF)-1 production as measured by ELISA. GECs exposed to TGF-
1
demonstrated a dose- and time-dependent increase in apoptosis.
ANG II-induced apoptosis was significantly inhibited by
addition of anti-TGF-
1 antibody. ANG II also upregulated the
expression of Fas, FasL, and Bax and downregulated the expression of
Bcl-2 in GECs. These studies suggest that ANG II induces GEC
apoptosis by a mechanism involving TGF-
1 expression that
may, importantly, contribute to the pathogenesis of glomerulosclerosis.
angiotensin II; glomerular epithelial cells; transforming growth
factor-; apoptosis; glomerulosclerosis
![]() |
INTRODUCTION |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
GLOMERULOSCLEROSIS IS A
COMMON pathological process in the progression of renal injury
and is characterized by glomerular cell loss and accumulation of
extracellular matrix (ECM) proteins (11, 19, 28). Numerous
clinical and experimental studies have implicated the renin-angiotensin
system (RAS) in the pathogenesis of this pattern of glomerular
abnormalities (23, 43, 47). ANG II, the effector molecule
of RAS, is known to exert various actions in diverse tissues and cells.
ANG II contributes to glomerular pathobiology through not only its
hemodynamic effects but also its nonhemodynamic effects (or direct
effects) on glomerular growth and sclerosis (2, 10, 43).
ANG II stimulates ECM protein synthesis in cultured mesangial cells by
induction of transforming growth factor (TGF)- expression
(15). In vivo administration of ANG II to animals
significantly increases the production of ECM proteins and expression
of TGF-
in the glomerulus (15). Inhibition of RAS with
angiotensin-converting enzyme inhibitors and ANG II receptor
antagonists attenuates the progression of glomerulosclerosis (18,
40). ANG II blockade also decreases the expression of TGF-
.
The interaction between ANG II and TGF-
has been considered to play
an important role in human and experimental models of
glomerulosclerosis (5).
Recent investigations suggest that an altered balance between cell survival and cell death may result in a loss of glomerular cells, which underlies the development of glomerulosclerosis (13, 33, 35). Apoptosis in glomerular cells has been demonstrated in human diseases (39) and experimental models of the remnant kidney (13, 39), diabetes (48), and hypertensive nephrosclerosis (46), where the increased activity of ANG II may be implicated. However, there are no data on whether ANG II can induce apoptosis in glomerular cells in vivo or in vitro. The mechanism of glomerular cell apoptosis induction remains unknown. In addition to its effect on cell proliferation and growth, ANG II has been shown to induce apoptosis in a variety of human and animal cells in culture, such as vascular smooth muscle cells (44), myocytes (16), fibroblasts (45), endothelial cells (7), and alveolar epithelial cells (42). ANG II-induced apoptosis is believed to be mediated by the ANG II type 2 (AT2) receptor, but there are also reports of the ANG II type 1 (AT1) receptor mediating apoptosis (4, 45).
Glomerular visceral epithelial cells (GECs), or podocytes, are one of
the major cell types in the glomerulus. Increasing evidence suggests
that GEC injury or loss plays a pivotal role in the initiation and
progression of glomerulosclerosis (17, 20, 29, 32). GECs
are situated on the glomerular basement membrane and presumably are
subjected to the direct effects of intrarenal ANG II activation under
pathological conditions. GECs have been documented to express both
AT1 and AT2 receptors (36).
However, a few studies have been carried out to evaluate the effects of
ANG II on cellular functions and structure in GECs (12,
37), but the question of whether ANG II affects survival of GECs
still remains unknown. Therefore, the present investigation was
designed to study the effect of ANG II on apoptosis in cultured
GECs and to evaluate the effects of ANG II receptor antagonists and
TGF-1 on cell apoptosis in response to ANG II.
![]() |
METHODS |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
GEC culture. GECs were cultured from isolated glomeruli of Sprague-Dawley rats (Harlan, Indianapolis, IN) as previously described (9, 31, 34). Briefly, glomeruli were isolated by differential sieving of minced cortices, collagenase digested, and plated. Early cellular outgrowths at 5-7 days were selectively removed by a cylinder cloning technique. Cells were replated, and plates growing pure colonies were then expanded. GECs were identified by currently recognized criteria, including their characteristic polygonal appearance as seen on phase-contrast microscopy, sensitivity to puromycin aminonucleoside, positive stain for podocalyxin, heparan sulfate proteoglycan core protein, and vimentin, and negative stain for myosin and factor VIII. The cells were maintained in culture with media containing 50% DMEM, 50% Ham's F-12 (GIBCO BRL, Grand Island, NY), 5% Nu-serum (Collaborative Biomedical Products, Bedford, MA), 5 µg/ml insulin, 5 µg/ml transferrin, and 5 µg/ml selenium (ITS; Collaborative Biomedical Products) at 37°C in 5% CO2. GECs were used for experiments between passages 8 and 12.
Experimental treatments of GECs.
Equal numbers of GECs were plated and grown to subconfluence. Cells
were washed twice with PBS and then incubated in media (+1% FCS)
containing buffer (control) or variable concentrations of ANG II
(Sigma, St. Louis, MO), ANG III, ANG IV (3-8),
ANG-(1-7) (Bachem Bioscience, King of Prussia, PA),
or TGF-1 (R&D Systems, Minneapolis, MN) for the indicated times. In
separate experiments, GECs were treated with ANG II in the presence of
losartan (Merck, Rahway, NJ), PD-123319 (a selective AT2
receptor antagonist; Parke-Davis Pharmaceutical, Ann Arbor, MI), or
losartan+PD-123319 or anti-TGF-
1 antibody (R&D Systems) for 1, 18, or 24 h.
Detection of apoptosis by cell nucleus staining. Morphological evaluation of GEC apoptosis was carried out by staining the cell nucleus with H-33342 (Molecular Probes, Portland, OR) and propidium iodide (Sigma). H-33342 stains the nuclei of live cells and identifies apoptotic cells by increased fluorescence, whereas propidium iodide costains the necrotic cells (pink). Double staining by these two dyes provides the percentage of live, apoptotic, and necrotic cells under control and experimental conditions (38). Briefly, at the end of the incubation period as described in Experimental treatments of GECs, cells were washed and stained with H-33342 (1 µg/ml) for 7 min at 37°C. Then, cells (without a wash) were placed on ice with the addition of propidium iodide (final concentration of 1 µg/ml). Cells were incubated with both dyes for 10 min, and the incubation was protected from light. The stained cells were then examined under ultraviolet light with a Hoechst filter (Nikon, Melville, NY). The percentage of live, apoptotic, and necrosed cells was recorded in eight random fields by two observers who were unaware of the experimental conditions.
DNA fragmentation assay: gel electrophoresis. This is a simple method that is specific for isolation and confirmation of DNA fragments from apoptotic cells (14). Briefly, GECs grown in 100-mm petri dishes were treated as described in Glomerular epithelial cell culture, washed twice with PBS, and then lysed in DNA lysis buffer (1% Nonidet P-40 in 20 mM EDTA and 50 mM Tris · HCl, pH 7.5). After centrifugation, the supernatant was collected and the extraction was repeated. The supernatants were brought to 1% SDS and treated for 2 h with RNase A (final concentration of 5 µg/µl) at 56°C followed by digestion with proteinase K (final concentration of 2.5 µg/µl) for 2 h at 37°C. After addition of 0.5 vol of 10 M ammonium acetate, the DNA was precipitated with 2.5 vol of ethanol, dissolved in loading buffer, and separated by electrophoresis on a 1.6% agarose gel containing 10 µg/ml ethidium bromide.
ELISA for TGF-1.
TGF-
1 protein from cell culture supernatants of GECs treated as
described above for 6 and 18 h was measured by a TGF-
1-specific sandwich ELISA kit according to the manufacturer's instructions (Promega, Madison,WI). To assay for total TGF-
1, samples were acidified with 1 N HCl for 15 min at room temperature and then neutralized by the addition of 1 N NaOH. Results are expressed as
TGF-
1 level in nanograms per milligram of total cell protein content.
Protein extraction and Western blot analysis. Protein extraction and Western blot analysis were performed as described previously (8). Briefly, after experimental treatments, GECs were washed twice with cold PBS and lysed in a modified radioimmunoprecipitation assay buffer (1 × PBS, 1% Nonidet P-40, 0.5% sodium deoxycholate, 1 mM sodium orthovanadate, 0.1% SDS, 10 µl of protease inhibitor cocktail/ml of buffer, and 100 µg/ml phenylmethylsulfonyl fluoride) for 1 h on ice. The cell lysates were centrifuged at 15,000 g for 20 min at 4°C. The supernatant was collected, and the protein concentration of the supernatant was determined by using a bicinchoninic acid protein assay kit (Pierce, Rockford, IL). The proteins (20 µg/lane) were separated on a 10-15% SDS-polyacrylamide gel that was electrophoresed under reduced conditions and transferred onto a nitrocellulose membrane by using a Bio-Rad Western blot analysis apparatus. After transfer, blots and gels were stained with Ponceau S to check for complete protein transfer and equal loading. The blots were treated with 5% nonfat dried milk for 60 min at room temperature and then incubated overnight at 4°C with the primary polyclonal antibodies to Fas, FasL, Bax, Bcl-2, and AT1 and AT2 receptors (Santa Cruz Biotechnology, Santa Cruz, CA) followed by incubation with the corresponding horseradish peroxidase-labeled secondary antibody (Santa Cruz Biotechnology) for 1 h at room temperature. The blots were developed by using a chemiluminescence detection kit (ECL; Amersham Life Science, Arlington Heights, IL) and exposed to Kodak X-OMAT AR film. Quantitative densitometry was performed on the identified bands by using a computer-based measurement system.
Statistical analysis. For comparison of mean values between two individual groups, an unpaired Student's t-test was used. Comparison of values among multiple groups was performed by one-way ANOVA, and a Newman-Keuls multiple range analysis was used to calculate a q-value. Results are from four to five independent experiments, each conducted in triplicate, and are expressed as means ± SE. Statistical significance was defined as P < 0.05.
![]() |
RESULTS |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
ANG II induces GEC apoptosis.
To evaluate the effect of ANG II on GEC apoptosis, cells were
plated in 24-well plates, grown to subconfluence, and incubated with
either buffer (control) or variable concentrations of ANG II
(1012 to 10
6 M) for 18 h. At the end
of the incubation period, cells were stained for apoptosis. As
shown in Fig. 1, ANG II induced
GEC apoptosis in a dose-dependent manner. At a higher
concentration (10
6 M), ANG II also induced GEC necrosis
(5.6 ± 1.6 vs. 0.3 ± 0.3% of control, P < 0.05). We then evaluated the time course during which ANG II could
induce GEC apoptosis. As shown in Fig.
2, ANG II (10
8 M) promoted
GEC apoptosis in a time-dependent manner. Figure 3 shows a representative morphological
view of ANG II-induced GEC apoptosis.
|
|
|
Effects of ANG II receptor antagonists on ANG II-induced
apoptosis.
To determine whether AT1 or AT2 receptors are
involved in the mediation of ANG II-induced apoptosis, GECs
were pretreated for 30 min with either losartan (106 M),
a selective AT1 receptor antagonist, or PD-123319
(10
6 M), a selective AT2 receptor antagonist,
or with a combination of both and then treated with the addition of ANG
II (10
8 M) for 18 h. As shown in Fig.
4, addition of losartan or PD-123319 significantly inhibited ANG II-induced GEC apoptosis, but the addition of both receptor antagonists prevented it.
|
Effect of ANG II on TGF-1 protein production in GECs.
To study the effect of ANG II on TGF-
1 protein production, GECs were
incubated with ANG II (10
8 M) in the presence or absence
of losartan (10
6 M) or PD-123319 (10
6 M),
and measurement of TGF-
1 protein in cultured supernatants was
performed by using a specific ELISA. As shown in Fig.
5, ANG II stimulated TGF-
1 secretion
by GECs at 6 and 18 h (2.0- and 1.7-fold increases vs. respective
control, P < 0.05). ANG II-stimulated TGF-
1
production was significantly diminished in the presence of losartan or
PD-123319.
|
Effect of anti-TGF-1 antibody on ANG II-induced GEC
apoptosis.
We first evaluated the effect of TGF-
1 on GEC apoptosis. As
shown in Fig. 6, TGF-
1 in
concentrations
0.5 ng/ml significantly enhanced GEC apoptosis
(TGF-
1 0.5 ng/ml, 2.9 ± 0.4%; 1 ng/ml, 11.9 ± 1.5%;
and 2.5 ng/ml, 17.5 ± 0.9% apoptotic cells/field) compared
with control (0.9 ± 0.3% apoptotic cells/field,
P < 0.05, n = 4). TGF-
1 also
enhanced GEC apoptosis in a time-dependent manner (Fig.
7).
|
|
|
DNA fragmentation assay.
DNA gel electrophoresis was used to confirm the formation of
low-molecular-weight DNA fragments in the apoptotic GECs. As illustrated in Fig. 9, ANG II-treated
cells showed increased integer multiples of 180 bp in the form of a
ladder pattern. The effect of ANG II on DNA fragmentation in GECs was
partially prevented by the addition of the AT1 receptor
antagonist losartan or the AT2 receptor antagonist
PD-123319 and completely prevented by the addition of both receptor
antagonists. TGF-1 antibody also attenuated ANG II-induced DNA
fragmentation in GECs.
|
Effect of ANG II on Fas, FasL, Bax, and Bcl-2 production.
Altered expression of cell death and cell survival proteins such as
Fas, FasL, Bax, and Bcl-2 has been demonstrated to play an important
role in the induction of apoptosis; therefore, we evaluated the
effects of ANG II and its receptor antagonists on expression in GECs of
these apoptosis-related proteins by Western blot analysis. As
illustrated, ANG II significantly enhanced Fas (Fig.
10A), FasL (Fig.
10B), and Bax (Fig. 10C) in GECs. On the
contrary, Bcl-2 expression was downregulated in response to ANG II
stimulation (Fig. 10D). However, in the presence of either
losartan or PD-123319, the increments in Fas, FasL, and Bax expression
were inhibited. In contrast, ANG II-induced downregulation of the Bcl-2
level was inhibited only by losartan and not by PD-123319.
|
![]() |
DISCUSSION |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
The present study shows that ANG II induces GEC apoptosis
in a dose- and time-dependent manner. ANG II also induced necrosis in
GEC at the higher concentration. ANG II-induced apoptosis was prevented by simultaneous incubation of both losartan and PD-123319. Furthermore, ANG II stimulated TGF-1 production and anti-TGF-
1 antibody attenuated the ANG II-induced GEC apoptosis. To our
knowledge, the present investigation is the first demonstration that
apoptosis occurs in cultured cells of glomerular origin in
response to ANG II.
Numerous studies have suggested that ANG II plays an important role in
the development of glomerulosclerosis (23, 43, 47). The
mechanisms by which ANG II contributes to the pathological process have
been attributed to its hemodynamic and nonhemodynamic effects (or
direct effects) (2, 10, 42). As Lapinski et al.
(21) reported in the isolated perfused kidney, continuous infusion of ANG II induced a loss of glomerular size permselectivity and an increase in urinary protein excretion rate. Arai et al. (3) demonstrated glomerular sclerosis in rats by
transfection of genes for renin and angiotensinogen into the kidney. In
vivo administration of ANG II to animals significantly increased the accumulation of ECM proteins and expression of TGF- in the glomeruli (15). In vitro ANG II treatment promoted renal cell growth
associated with an increase in the synthesis of ECM proteins (10,
43).
Glomerulosclerosis is characterized by progressive accumulation of ECM and loss of resident glomerular cells (11, 19, 28). Recent data suggest that an imbalance between cell survival and death may result in a loss of glomerular cells, which underlies the development of glomerulosclerosis (35, 39, 46, 48). ANG II, in addition to its growth-promoting effects, has been demonstrated to induce apoptosis in several nonrenal cells in culture (7, 16, 42, 44, 45). In the present study, we tested whether ANG II affects the survival of GECs in culture. Our data clearly indicate that ANG II induces GEC apoptosis in a dose- and time-dependent manner. Because GECs have been shown to express both AT1 and AT2 receptors (36), we then determined whether AT1 or AT2 receptors are involved in the mediation of the ANG II-induced apoptosis. To our surprise, the proapoptotic effects of ANG II were only partially blocked by treatment with either losartan or PD-123319 but were completely blocked by their combination, suggesting that ANG II-induced GEC apoptosis is associated with activation of both receptors. It is generally considered that the proapoptotic effects of ANG II are mediated by the AT2 receptor, whereas the growth-promoting effects are mediated by the AT1 receptor (4). However, recent studies of myocytes demonstrated the involvement of the AT1 receptor in apoptosis (22). The results of the present investigation indicate that both AT2 and AT1 receptors are involved in ANG II-induced GEC apoptosis. Our findings are consistent with recent data showing that both receptors have similar effects on apoptosis in ANG II-treated human endothelial cells (7) and in ANG II-infused rat kidneys (6). It is possible that ANG II may induce cross-talk between the AT1 and AT2 receptors or stimulate a common event of the two receptor pathways, such as the production of a given mediator or cytokine, that leads to cell apoptosis (6, 7).
GECs, or podocytes, are one of the major cell types within the glomerulus and play an important role in maintaining normal structure and function of the glomerular basement membrane. Under pathological conditions, GECs would be subjected to the detrimental effects of intrarenal ANG II activation. Injury or loss in GECs may be the sequelae of ANG II-induced apoptosis. Our present studies extend the role of ANG II as a proapoptotic cytokine to contribute to the pathobiology of glomerulosclerosis.
It has been shown that GECs cultured from human as well as rat kidneys
produce TGF-1 (9, 41). The results of the present study
demonstrate that ANG II stimulates TGF-
1 protein synthesis in rat
GECs. Moreover, both AT1 and AT2 receptor
antagonists significantly inhibit ANG II-induced TGF-
1 production.
Thus the signal transduction of the ANG II effect is also considered to
occur through both AT1 and AT2 receptors. The
coincidence of ANG II-stimulated TGF-
1 expression and cell
apoptosis through the signal transduction of both receptor
types suggests that TGF-
1 may be an important mediator of ANG
II-induced GEC apoptosis.
TGF- is a multifunctional growth factor that can either inhibit or
stimulate cell proliferation and growth. We have recently reported that
TGF-
promotes apoptosis in glomerular mesangial cells in
vitro (27). TGF-
is also involved in apoptosis
of renal tubular cells exposed to a mechanical stretch
(24) and in apoptosis of podocytes in transgenic mice
(32). In the present study, we found that TGF-
1
treatment was associated with a dose- and time-dependent enhancement of
GEC apoptosis. We further hypothesized that the newly produced
TGF-
, in response to ANG II, may be involved in cell
apoptosis. When GECs were exposed to ANG II in the presence of
neutralizing antibody to TGF-
1, we noticed an obvious reduction in
apoptosis. These results support our hypotheses that ANG II stimulates TGF-
1 production and that the newly synthesized TGF-
1 is involved in cell apoptosis.
Both Fas and FasL have been implicated in the induction of increased cell apoptosis in glomerular injury (26). In the present study, we have shown that ANG II-induced apoptosis is associated with enhanced expression of Fas and FasL in GECs. In addition, ANG II induced an accumulation of Bax, an apoptosis-promoting factor (25), and a reduction of Bcl-2, an apoptosis-preventing factor (1). We have further demonstrated that ANG II-stimulated protein levels of Fas, FasL, and Bax are inhibited by treatment with either losartan or PD-123319, raising the possibility that both AT1 and AT2 receptor transduction pathways are involved in the induction of Fas, FasL, and Bax. In contrast, ANG II-induced reduction of Bcl-2 is specific only for the AT1 receptor, because losartan, not PD-123319, modulates the ANG II effect on Bcl-2 expression. However, our data on altered expression of the apoptosis-related proteins specific for ANG II receptor tranduction may provide the molecular basis for the enhanced cell susceptibility to apoptosis.
Recently, Saleh et al. (30) reported that thapsigargin triggered mesangial cell apoptosis through the induction of a sustained increase of cytoplasmic-free concentration of calcium. On the other hand, platelet-derived growth factor, which is known to elevate mesangial cell cytosolic calcium, inhibited thapsigargin-induced mesangial cell apoptosis. Saleh et al. suggested that the time and duration of the cytosolic calcium peak may determine whether a cell will enter into a proliferative or apoptotic phase. At present, data on cytosolic calcium in glomerular epithelial cells in response to various vasoactive agents are scanty and worth pursuing in future studies.
In summary, we have shown that ANG II can induce GEC apoptosis
in culture and that the proapoptotic effects are mediated by both
AT1 and AT2 receptors. Our studies further
demonstrate the involvement of TGF-1 and an altered expression of
apoptotic regulatory proteins in the ANG II-induced
apoptosis. These findings may indicate an important role for
ANG II as a proapoptotic cytokine contributing to the pathobiology
of glomerulosclerosis.
![]() |
ACKNOWLEDGEMENTS |
---|
This work was supported by National Institute on Drug Abuse Grant RO1-DA-12111.
![]() |
FOOTNOTES |
---|
A portion of this work was presented at the 33rd annual meeting of the American Society of Nephrology, October 10-16, 2000 (Toronto, Ontario, Canada), and published in abstract form (J Am Soc Nephrol 11: 419A, 2000).
Address for reprint requests and other correspondence: P. C. Singhal, Div. of Kidney Disease and Hypertension, Rm. 228, Long Island Jewish Medical Ctr., New Hyde Park, NY 11040 (E-mail singhal{at}lij.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.
First published January 8, 2002;10.1152/ajprenal.00240.2001
Received 1 August 2001; accepted in final form 3 January 2002.
![]() |
REFERENCES |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
1.
Adams, JM,
and
Cory S.
The Bcl-2 protein family: arbiters of cell survival.
Science
281:
1322-1326,
1998
2.
Anderson, S,
Meyer TW,
Rennke HG,
and
Brenner BM.
Control of glomerular hypertension limits glomerular injury in rats with reduced renal mass.
J Clin Invest
76:
612-619,
1985[ISI][Medline].
3.
Arai, M,
Wada A,
Isaka Y,
Akagi Y,
Sugiura T,
Miyazaki M,
Moriyama T,
Kaneda Y,
Naruse K,
Naruse M,
Orita Y,
Ando A,
Kamada T,
Ueda N,
and
Imai E.
In vivo transfection of genes for renin and angiotensinogen into the glomerular cells induced phenotypic change of the mesangial cells and glomerular sclerosis.
Biochem Biophys Res Commun
206:
525-532,
1995[ISI][Medline].
4.
Ardaillou, R.
Angiotensin II receptors.
J Am Soc Nephrol
10:
S30-S39,
1999[ISI][Medline].
5.
Border, WA,
and
Noble NA.
Interaction of transforming growth factor- and angiotensin II in renal fibrosis.
Hypertension
31:
181-188,
1998
6.
Cao, Z,
Kelly DJ,
Cox A,
Cassley D,
Forbes JM,
Mantinello P,
Dean R,
Gilbert RE,
and
Cooper ME.
Angiotensin type 2 receptor is expressed in the adult rat kidney and promotes cellular proliferation and apoptosis.
Kidney Int
58:
2437-2451,
2000[ISI][Medline].
7.
Dimmeler, S,
Rippmann V,
Weiland U,
Haendeler J,
and
Zeiher AM.
Angiotensin II induces apoptosis of human endothelial cells: Protective effect of nitric oxide.
Circ Res
81:
970-976,
1997
8.
Ding, G,
Franki N,
Kapasi AA,
Reddy K,
Gibbons N,
and
Singhal PC.
Tubular cell senescence and expression of TGF-1 and p21WAF1/CIP1 in tubulointerstitial fibrosis of aging rats.
Exp Mol Pathol
70:
43-53,
2001[ISI][Medline].
9.
Ding, G,
van Goor H,
Ricardo SD,
Orlowski JM,
and
Diamond JR.
Oxidized LDL stimulates the expression of TGF- and fibronectin in human glomerular epithelial cells.
Kidney Int
51:
147-154,
1997[ISI][Medline].
10.
Egido, J.
Vasoactive hormones and renal sclerosis.
Kidney Int
49:
578-598,
1996[ISI][Medline].
11.
Fogo, AB.
Progression and potential regression of glomerulosclerosis.
Kidney Int
59:
804-819,
2001[ISI][Medline].
12.
Gloy, J,
Henger A,
Fischer KG,
Nitschke R,
Mundel P,
Bleich M,
Schollmeyer P,
Greger R,
and
Pavenstadt H.
Angiotensin II depolarizes podocytes in the intact glomerulus of the rat.
J Clin Invest
99:
2772-2781,
1997
13.
Hattori, T,
Shindo S,
and
Kawamura H.
Apoptosis and expression of Bax protein and Fas antigen in glomeruli of a remnant-kidney model.
Nephron
79:
186-191,
1998[ISI][Medline].
14.
Herrmann, H,
Lorenz HM,
Voll R,
Grunke M,
Woith W,
and
Kalden JR.
A rapid and simple method for the isolation of apoptotic DNA fragments.
Nucleic Acids Res
22:
5506-5507,
1994[ISI][Medline].
15.
Kagami, S,
Border WA,
Miller DE,
and
Noble NA.
Angiotensin II stimulates extracellular matrix protein synthesis through induction of transforming growth factor- expression in rat glomerular mesangial cells.
J Clin Invest
93:
2431-2437,
1994[ISI][Medline].
16.
Kajstura, J,
Cigola E,
Malhotra A,
Li P,
Cheng W,
Meggs LG,
and
Arversa P.
Angiotensin II induces apoptosis of adult ventricular myocytes in vitro.
J Mol Cell Cardiol
29:
859-870,
1997[ISI][Medline].
17.
Kasinath, BS.
Resident glomerular cells in glomerular injury: Glomerular epithelial cells.
Semin Nephrol
11:
294-303,
1991[ISI][Medline].
18.
Keane, WF,
Anderson S,
Aurell M,
de Zeeuw D,
Narins RD,
and
Povar G.
Angiotensin converting enzyme inhibitors and progressive renal insufficiency.
Ann Intern Med
111:
503-516,
1989[ISI][Medline].
19.
Klahr, S,
Schreiner G,
and
Ichikawa I.
The progression of renal disease.
N Engl J Med
318:
1657-1666,
1988[Abstract].
20.
Kriz, W,
Gretz N,
and
Lemley KV.
Progression of glomerular diseases: is the podocyte the culprit?
Kidney Int
54:
687-697,
1998[ISI][Medline].
21.
Lapinski, R,
Perico N,
Remuzzi A,
Sangalli F,
Benigni A,
and
Remuzzi G.
Angiotensin II modulates glomerular capillary permselectivity in rat isolated perfused kidney.
J Am Soc Nephrol
7:
653-660,
1996[Abstract].
22.
Leri, A,
Claudio PP,
Li Q,
Wang X,
Reiss K,
Wang S,
Malhotra A,
Kajstura J,
and
Anvensa P.
Stretch-mediated release of angiotensin II induces myocyte apoptosis by activating p53 that enhances the local renin-angiotensin system and decreases the Bcl-2-to-Bax protein ratio in the cell.
J Clin Invest
101:
1326-1342,
1998
23.
Matsusaka, T,
Hymes J,
and
Ichikawa I.
Angiotensin in progressive renal diseases: theory and practice.
J Am Soc Nephrol
7:
2025-2043,
1996[Abstract].
24.
Miyajima, A,
Chen J,
Lawrence C,
Ledbetter S,
Soslow RA,
Stern J,
Jha S,
Pigato J,
Lemer ML,
Poppas DP,
Vaughan ED, Jr,
and
Felsen D.
Antibody to transforming growth factor- ameliorates tubular apoptosis in unilateral ureteral obstruction.
Kidney Int
58:
2301-2313,
2000[ISI][Medline].
25.
Oltvai, ZN,
Milliman CL,
and
Korsmeyer S.
Bcl-2 heterodimerizes in vivo with a conserved homolog, Bax, that accelerates programmed cell death.
Cell
74:
609-619,
1993[ISI][Medline].
26.
Ortiz, A.
Apoptotic regulatory proteins in renal injury.
Kidney Int
58:
467-485,
2000[ISI][Medline].
27.
Patel, P,
Varghese E,
Ding G,
Fan S,
Kapasi A,
Reddy K,
Franki N,
Nahar N,
and
Singhal PC.
Transforming growth factor beta induces mesangial cell apoptosis through NO- and p53-dependent and -independent pathways.
J Investig Med
48:
403-410,
2000[ISI][Medline].
28.
Pesce, CM,
Striker L,
Peter E,
Elliot S,
and
Striker GE.
Glomerulosclerosis at both early and late stage is associated with cell turnover in mice transgenic for growth hormone.
Lab Invest
65:
601-605,
1991[ISI][Medline].
29.
Rennke, HG.
How does glomerular epithelial cell injury contribute to progressive glomerular damage?
Kidney Int
45:
S58-S63,
1994[ISI].
30.
Saleh, H,
Schlatter E,
Lang D,
Pauels HG,
and
Heidenreich S.
Regulation of mesangial cell apoptosis and proliferation by intracellular Ca2+ signals.
Kidney Int
58:
1870-1884,
2000[ISI][Medline].
31.
Sanwal, V,
Pandya M,
Bhaskaran M,
Franki N,
Reddy K,
Ding G,
Kapasi A,
Valderrama E,
and
Singhal PC.
Puromycin aminonucleoside induces glomerular epithelial cell apoptosis.
Exp Mol Pathol
70:
54-64,
2001[ISI][Medline].
32.
Schiffer, M,
Bitzer M,
Roberts Ian SD,
Kopp JB,
ten Dijke P,
Mundel P,
and
Bottinger EP.
Apoptosis in podocytes induced by TGF- and Smad7.
J Clin Invest
108:
807-816,
2001
33.
Shankland, SJ,
Floege J,
Thomas SE,
Nangaku M,
Hugo C,
Pippin J,
Henne K,
Hockenberry DM,
Johnson RJ,
and
Couser WG.
Cyclin kinase inhibitors are increased during experimental membranous nephropathy: Potential role in limiting glomerular epithelial cell proliferation in vitro.
Kidney Int
52:
404-413,
1997[ISI][Medline].
34.
Shankland, SJ,
Pippin JW,
and
Couser WG.
Complement (C56-9) induces glomerular epithelial cell DNA synthesis but not proliferation in vitro.
Kidney Int
56:
538-548,
1999[ISI][Medline].
35.
Shankland, SJ,
and
Wolf G.
Cell cycle regulatory proteins in renal disease: role in hypertrophy, proliferation, and apoptosis.
Am J Physiol Renal Physiol
278:
F515-F529,
2000
36.
Sharma, M,
Sharma R,
Greene AS,
McCarthy ET,
and
Savin VJ.
Documentation of angiotensin II receptors in glomerular epithelial cells.
Am J Physiol Renal Physiol
274:
F623-F627,
1998
37.
Sharma, R,
Lovell HB,
Wiegmann TB,
and
Savin VJ.
Vasoactive substances induce cytoskeletal changes in cultured rat glomerular epithelial cells.
J Am Soc Nephrol
3:
1131-1138,
1992[Abstract].
38.
Singhal, PC,
Reddy K,
Franki N,
and
Ding G.
HIV-1 gp120 envelope protein modulate proliferation of human glomerular epithelial cells.
J Cell Biochem
76:
61-70,
1999[ISI][Medline].
39.
Sugiyama, H,
Kashihara N,
Makino H,
Yamasaki Y,
and
Ota Z.
Apoptosis in glomerular sclerosis.
Kidney Int
49:
103-111,
1996[ISI][Medline].
40.
Taal, MW,
and
Brenner BM.
Renoprotective benefits of RAS inhibition: from ACEI to angiotensin II antagonists.
Kidney Int
57:
1803-1817,
2000[ISI][Medline].
41.
Tsunoda, S,
Yamabe H,
Osawa H,
Kaizuka M,
Shirato K,
and
Okumura K.
Cultured rat glomerular epithelial cells show gene expression and production of transforming growth factor-: expression is enhanced by thrombin.
Nephrol Dial Transplant
16:
1776-1782,
2001
42.
Wang, R,
Zagariya A,
Ibarra-sunga O,
Giidea C,
Ang E,
Deshmukh S,
Chaudhary G,
Baraboutis J,
Filippatos G,
and
Uhal B.
Angiotensin II induces apoptosis in human and rat alveolar epithelial cells.
Am J Physiol Lung Cell Mol Physiol
276:
L885-L889,
1999
43.
Wolf, G,
and
Neilson EG.
Angiotensin II as a renal growth factor.
J Am Soc Nephrol
3:
1531-1540,
1993[Abstract].
44.
Yamada, T,
Akishhita M,
Pollman MJ,
Gibbons GH,
Dzau VJ,
and
Horiuchi M.
Angiotensin II type 2 receptor mediates vascular smooth muscle cell apoptosis and antagonizes angiotensin II type 1 receptor action: an in vitro gene transfer study.
Life Sci
63:
289-295,
1998.
45.
Yamada, T,
Horiuchi M,
and
Dzau VJ.
Angiotensin II type 2 receptor mediates programmed cell death.
Proc Natl Acad Sci USA
93:
156-160,
1996
46.
Ying, WZ,
Wang PX,
and
Sanders PW.
Induction of apoptosis during development of hypertensive nephrosclerosis.
Kidney Int
58:
2007-2017,
2000[ISI][Medline].
47.
Yoshida, Y,
Kawamura M,
Ikomo A,
Fogo A,
and
Ichikawa I.
Effects of antihypertensive drugs on glomerular morphology.
Kidney Int
36:
626-635,
1989[ISI][Medline].
48.
Zhang, W,
Khanna P,
Chan LL,
Campbell G,
and
Ansari NH.
Diabetes-induced apoptosis in rat kidney.
Biochem Mol Med
61:
58-62,
1997[ISI][Medline].