 |
||||
| 2007 JASN IMPACT FACTOR 7.111 | HOME AUTHOR INFO EDITORIAL BOARD SUBSCRIBE FEEDBACK ALERTS HELP | |||
| CURRENT ISSUE | ARCHIVES | JASN Express | ONLINE SUBMISSION | |
|
||||
| 2007 JASN IMPACT FACTOR 7.111 | HOME AUTHOR INFO EDITORIAL BOARD SUBSCRIBE FEEDBACK ALERTS HELP | |||
| CURRENT ISSUE | ARCHIVES | JASN Express | ONLINE SUBMISSION | |
*Division of Nephrology and Immunology and Institute of Clinical Chemistry and Pathobiochemistry, University of Aachen, Aachen, Germany; Replidyne, Inc., Denver, Colorado; and Gilead Sciences, Inc., Boulder, Colorado.
Correspondence to Dr. Jürgen Floege, University of Aachen, Medizinische Klinik II, Klinikum der RWTH, Pauwelsstrasse 30, 52074 Aachen, Germany. Phone: 49-241-8089530; Fax: 49-241-8888446; E-mail: juergen.floege{at}post.rwth-aachen.de
 |
Abstract |
|---|
 Top Abstract IntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
|
Introduction |
|---|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
TGF-ß is a multifunctional cytokine that plays a central role in tissue repair, wound healing, and modulation of inflammation (2,3). With respect to matrix synthesis in the kidney, in vitro data have demonstrated that TGF-ß regulates the production of proteoglycans, fibronectin, and collagens in glomerular mesangial, epithelial, and endothelial cells as well as in tubular cells (4). Several in vivo studies have confirmed a profibrotic role of TGF-ß in the kidney: glomerulosclerosis and/or glomerular matrix accumulation was induced by overexpression of TGF-ß (5,6) or significantly diminished in multiple studies by interfering with the TGF-ß system (7–12).
PDGF, in particular the PDGF-B chain, is known to induce glomerular mesangial cell proliferation and extracellular matrix protein accumulation in vitro (1,13,14). In vivo infusion of recombinant PDGF-B into rats or transfection of glomeruli with PDGF-B cDNA (5,15,16) has resulted in glomerular cell and matrix accumulation. Experiments with a neutralizing antibody against PDGF (17) or, more recently, with a PDGF-B–specific DNA-based aptamer (18), have demonstrated that antagonism of PDGF-B can decrease mesangial cell proliferation and matrix accumulation in the anti–Thy 1.1 mesangioproliferative nephritis in rats. More important, transient antagonism of PDGF-B during the mesangioproliferative phase in the chronic anti–Thy 1.1. model completely prevented the development of renal failure and glomerular as well as tubulointerstitial scaring (19).
In view of the partially overlapping biologic activities of TGF-ß and PDGF-B in the glomerulus, the question has arisen whether the production and/or activity of these growth factors is interrelated. Strong evidence for such an interaction is provided by the observation that antagonism of TGF-ß or PDGF-B independently resulted in an almost complete inhibition of glomerular matrix accumulation and/or glomerulosclerosis in vivo (7,8,18,19). These data also suggest that TGF-ß and PDGF-B do not act in parallel but, rather, sequentially in vivo. However, the sequence of their activation has been unclear so far, because in vitro data obtained with glomerular cells have shown both an induction of TGF-ß by exogenous PDGF-B as well as of PDGF-B by exogenous TGF-ß (13,20–22). To better understand the relationship between TGF-ß and PDGF-B in vivo, we specifically antagonized PDGF-B in the rat model of anti–Thy1.1 glomerulonephritis and investigated the effects on the TGF-ß system.
|
Materials and Methods |
|---|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
0.1 nM) (18). On the basis of photocrosslinking experiments (23), the aptamer makes a point contact with human PDGF-B-chain at phenylalanine 84 (with isoleucine at position 83).
As a control aptamer, we used a sequence-scrambled analog of the aptamer conjugated to 40 kD PEG (18). The binding affinity of this scrambled aptamer (NX1976) for PDGF-BB (Kd 1 µM) is 10,000-fold lower compared with the binding affinity of the PDGF-B aptamer (Kd 0.1 nM) (18).
Experimental Model and Experimental Design
All animal studies were approved by the Institutional Review Board. Anti-Thy-1.1 mesangial proliferative glomerulonephritis was induced in 30 male Wistar rats (Charles River, Sulzfeld, Germany), weighing 140 to 160 g at the start of the experiment, by injection of 1 mg/kg monoclonal anti–Thy 1.1 antibody (clone OX-7; European Collection of Animal Cell Cultures, Salisbury, UK). Twenty-four of these rats were treated with the PDGF-B aptamer or the scrambled control dissolved in phosphate-buffered saline (pH 7.4) from days 3 to 7 after disease induction by subcutaneous micro-osmotic pumps (model Alzet 2001; Charles River). The respective daily dose was 5 mg aptamer/kg body weight. The treatment duration was chosen to treat rats from 1 d after the onset to the peak of mesangial cell proliferation, which in OX-7 induced anti–Thy1.1 nephritis occurs between days 6 and 9 after disease induction. Four groups of rats were studied: (1) 12 nephritic rats that received a total of 5 mg each of the PDGF-B aptamer (coupled to 19.6 mg 40 kd PEG), (2) 12 nephritic rats that received an equivalent amount of PEG-coupled scrambled aptamer, (3) 6 nephritic rats that remained untreated, and (4) 6 normal rats. The animals were killed on day 7 after disease induction. A renal cortical section of each rat was obtained for light microscopy. The remaining cortical tissue was pooled within the group with the renal cortex of a second rat in treatment groups 1 and 2. In groups 3 and 4, the renal cortex of three rats each was pooled. This tissue was used to generate a preparation of glomeruli by differential sieving (24). All glomerular isolates were checked microscopically and exhibited a purity >98%. One-half of the isolated glomeruli were used for the preparation of protein lysates and the other half for the isolation of RNA (see below).
For the evaluation of the time course of Smad2 and Smad7 expression in the anti–Thy1.1 model, nephritis was induced in 10 male Wistar rats (Charles River). The animals were killed, and kidney specimens for immunohistology were obtained before disease induction, as well as at 2 h and 7, 10, and 14 d after disease induction (n = 2 for each time point).
Renal Morphology
Tissue for light microscopy was fixed in methyl Carnoy’s solution and embedded in paraffin. Four-micron sections were stained with the periodic acid–Schiff reagent and counterstained with hematoxylin. In the periodic acid–Schiff–stained sections, the number of mitoses within 30 to 50 glomerular tufts was determined.
Immunoperoxidase Staining
Four-micron sections of methyl Carnoy’s–fixed biopsy tissue or formalin-fixed biopsy tissue were processed by an indirect immunoperoxidase technique, as described elsewhere (25). Primary antibodies included an affinity-purified polyclonal goat anti-human/bovine type IV collagen IgG preabsorbed with rat erythrocytes (Biozol, Birmingham, AL), an affinity-purified IgG fraction of a polyclonal rabbit anti-rat fibronectin antibody (Chemicon, Temecula, CA), a polyclonal goat anti-human Smad2 antibody (Santa Cruz Biotechnology, Heidelberg, Germany), a purified polyclonal rabbit anti phospho-Smad2 antibody (raised against the phosphorylated synthetic peptide SS(P)MS(P), kindly provided by P. ten Dijke, Division of Cellular Biochemistry, The Netherlands Cancer Institute, Amsterdam, the Netherlands), a polyclonal goat anti-human Smad7 IgG (Santa Cruz Biotechnology), and a polyclonal rabbit anti-human TGF-ßRII antibody (Santa Cruz Biotechnology). Negative controls consisted of substitution of the primary antibody with equivalent concentrations of normal rabbit or goat IgG. Additional negative controls for the specificity of the Smad2, Smad7, and TGF-ßRII immunohistology included overnight preincubation of the specific antibodies with an excess of the appropriate blocking peptides (Santa Cruz Biotechnology). All slides were evaluated by an observer who was unaware of the origin of the slides.
Glomerular staining for type IV collagen and fibronectin was evaluated by use of a semiquantitative scoring system, and the mean score per biopsy was calculated. Each score reflects mainly changes in the extent rather than intensity of glomerular staining and depends on the percentage of the glomerular tuft area showing positive staining: 0, absent staining or <5% of area stained; I, 5% to 25%; II, 25% to 50%; III, 50% to 75%; and IV, >75%.
Immunohistochemical Double Staining
Double immunostaining for the identification of the type of Smad2 or Smad7 expressing glomerular cells was performed by first staining the sections for Smad2 or Smad7 with polyclonal goat anti-human Smad2 or Smad7 antibodies (Santa Cruz Biotechnology) by use of an indirect immunoperoxidase procedure. Sections were then incubated with the IgG1 monoclonal antibody 1A4 against 
–smooth-muscle actin. –smooth-muscle actin in the glomerulus is exclusively expressed by activated mesangial cells. Negative controls included omission of either of the primary antibodies, in which case no double-staining was noted.
Western Blot Analysis
Isolated glomeruli were homogenized in 2 ml of Triton X-100 lysis buffer (50 mM Hepes [pH 7.5], 150 mM NaCl, 1.5 mM MgCl2, 1 mM ethyleneglycol-bis(ß-aminoethyl ether)-N,N'tetraacetic acid, 10% glycerol, 1% Triton X-100, 1 µg/ml aprotinin, 1 µg/ml leupeptin, 1 mM phenylmethylsulfonyl chloride, and 0.1 mM sodium orthovanadate) at 4°C. After incubation for 5 min, lysates were centrifuged at 4°C for 15 min at 10,000 x g. The protein concentrations in the lysates were determined according to the method of Lowry et al. (26). The soluble lysates were mixed 1:4 with 5x Laemmli buffer and heated for 5 min at 95°C. Soluble lysates (40 µg) were loaded per lane and separated by sodium dodecyl sulfate–polyacrylamide gel electrophoresis that used 4% acrylamide for the stacking gel and 10% to 15% acrylamide gel for the resolving gels (Smad2-Western, 10%; P-Smad2, 12.5%; and TGF-ß and Smad7, 15%). Protein was transferred to nitrocellulose membranes (pore size, 0.45 µm; Schleicher & Schuell, Keene, NH) and probed with polyclonal antibodies against human Smad2 (goat polyclonal antibody, Santa Cruz Biotechnology), phospho-Smad2 (rabbit antiserum raised against the phosphorylated synthetic peptide SS(P)MS(P), kindly provided by P. ten Dijke, Division of Cellular Biochemistry, The Netherlands Cancer Institute, Amsterdam, the Netherlands), Smad7 (rabbit antiserum [27], kindly provided by C.H. Heldin, Ludwig Institute for Cancer Research, Uppsala, Sweden), and human TGF-ß1 (rabbit polyclonal IgG, Santa Cruz Biotechnology). The primary antibodies were detected by use of horseradish peroxidase–conjugated goat anti-rabbit IgG (Vector Laboratories Inc., Burlingame, CA) or biotinylated rabbit anti-goat IgG in combination with avidin-coupled horseradish peroxidase (Zymed, San Francisco, CA, and Vector Laboratories Inc., respectively). Negative controls consisted of substitution of the primary antibody with equivalent concentrations of normal rabbit or goat IgG. Because of a presumed up-regulation during glomerulonephritis of some of the antigens that had to be analyzed, protein lysate derived from glomeruli of the scrambled aptamer–treated nephritic control group was used in these controls. Additional negative controls for the specificity of the Smad2 and TGF-ß1 Western blotting included overnight preincubation of the specific antibodies with an excess of the appropriate blocking peptides (Santa Cruz Biotechnology). This treatment completely abolished staining of the specific TGF-ß1 band and significantly weakened the staining of Smad2 protein.
To investigate whether Smad2 remains phosphorylated during glomerular tissue extraction and processing, two additional nephritic rats were treated with PDGF-B aptamer and the scrambled control. Renal cortical tissue of both animals was lysed and boiled immediately after death. Subsequent anti–phospho-Smad2 Western blot analysis with these tissues gave the same results compared with those of isolated and processed glomeruli, which thereby demonstrates an unaffected phosphorylation during glomerular tissue extraction (data not shown). The antibodies were visualized by the ECL system (Amersham Pharmacia Biotech, Freiburg, Germany). Subsequently, the intensity of the identified bands was quantified by densitometry that used the system of Biostep GmbH (Jahnsdorf, Germany). Specific band intensities were scanned and corrected for the relative intensities of a nonspecific band. The analysis software was from TotalLab (Phoretix International, Newcastle, UK).
Northern Blot Analysis
Total RNA was extracted from the isolated glomeruli with the guanidinium isothiocyanate/phenol/chloroform method by use of standard procedures (28). The RNA content and the purity of the samples obtained was determined by ultraviolet spectrophotometry at 260 and 280 nm. For Northern analysis, the RNA was denatured, and 10 µg/lane were electrophoresed through a denaturing 1% agarose/formaldehyde gel. The integrity of the RNA was assessed by visualization of ethidium bromide–stained 28S and 18S rRNA bands. Separated RNA was then transferred onto a nylon membrane (Hybond N, Amersham Pharmacia Biotech) by capillary blotting and cross linked with the use of ultraviolet light at 310 nm. Radioactive -32P–labeled cDNA probes were generated by use of the Megaprime DNA labeling system (Amersham Pharmacia Biotech), and hybridization was performed with the QuickHyb hybridization solution (Stratagene, Heidelberg, Germany). Band intensities were scanned as described above and corrected for the relative intensities of the 28S rRNA signal on the membrane.
For the detection of TGF-ßRI and TGF-ßRII mRNA, the hybridization probes were created by reverse transcription–PCR amplification that used the following gene-specific primers: rat TGF-ßRI (680-bp fragment) forward, 5'-CGTCTGCATTGCACTTATGC-3' and reverse, 5'-CTGTGGCAGAATCATGTCTC-3'; and rat TGF-ßRII (650-bp fragment) forward, 5'-CACTGTCCACTTGTGACAAC-3' and reverse, 5'-GGTCTCAAACTGCTCTGAAG-3'. The mouse TGF-ß1 probe used encoded part of the mature protein according to Genbank accession number M13177, nt 1220 to 1522 (29). The Smad2-specific hybridization probe was generated by restriction digestion of an expression construct for Flag tagged Smad2, which was described in Nakao et al. [30].
Reverse transcription–PCR reactions with the above-listed oligonucleotides were performed in a 30-µl reaction mix that included 4 µg of total rat liver RNA, 1 µl of oligo-dT primer (12 to 18 nt, 0.5 µg/µl, Life Technologies/BRL), 6 µl of M-MLV reverse transcriptase buffer (Life Technologies/BRL), 1.5 µl dNTP mix (10 mM each, Amersham Pharmacia Biotech), 1 µl RNase inhibitor (40 U/µl, Roche), 2 µl of M-MLV reverse transcriptase (200 U/µl, Life Technologies/BRL), and diethyl pyrocarbonate–treated H2O. The mix was incubated for 1 h at 42°C, 5 min at 80°C, and 1 min on ice and subsequently centrifuged; 1 µl of the cDNA was included in a standard 50-µl polymerase reaction mix and amplified under standard conditions with the appropriate primers. The amplified products were separated on a 1.5% agarose gel, eluted from the gel with the QIAEX method (Quiagen, Hilden, Germany), and used as probes in the Northern blots.
Statistical Analyses
All values of the PDGF-B– and scrambled aptamer–treated animals are expressed as mean ± SD. Statistical significance (defined as P < 0.05) was evaluated by ANOVA and Bonferroni t tests. The values for the untreated nephritic and normal animals are expressed as the mean and are excluded from the statistical analysis because only two samples per group (representing pooled tissue from three rats) were analyzed.
|
Results |
|---|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
|
|
Smad2 and Smad7 Expression in the Anti–Thy1.1 Nephritis
Smad2 and Smad7 are central mediators in the TGF-ß signaling system (30,37,38). Therefore, an analysis of the expression and activation of these proteins provides insight into the TGF-ß induced cellular activation. Because little is known about the glomerular localization of Smad2 and Smad7 in the anti–Thy1.1 nephritis model, we first evaluated the time course of their expression. In kidneys of healthy controls, occasional positive Smad2 staining was noted in the peritubular and glomerular capillary endothelium (Figure 3A). Renal arteriolar endothelium also stained positively. This expression pattern did not change during the course of the disease, but a significant increase in Smad2 expression was noted on day 7 in glomerular capillaries (Figure 3B) that decreased to the level of the control animals on days 10 and 14. Smad2/–smooth-muscle actin double immunostaining in the renal tissues confirmed a predominant nonmesangial expression of Smad2 (data not shown). Smad7 expression was absent in the glomerulus of healthy controls but was present in arterioles and some distal tubular and/or collecting duct cells (Figure 4A). Widespread glomerular Smad7 expression in a mesangial pattern first appeared at 2 h after disease induction, reached its maximum on day 7 (Figure 4B), and decreased thereafter. In parallel, tubular Smad7 expression also transiently became more widespread (Figure 4B). A predominant mesangial expression of Smad7 on day 7 after disease induction was confirmed by Smad7/–smooth-muscle actin double immunostaining (data not shown). Despite evidence of Smad2 and Smad7 regulation at the transcriptional level (39,40), at least in the case of Smad2 we did not detect glomerular overexpression on day 7 in nephritic rats (data not shown).
|
|
|
|
|
|
Discussion |
|---|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
Next, we assessed the glomerular expression of components of the TGF-ß system. Elsewhere, by use of an anti–Thy1.1 model induced by injection of anti-thymocyte serum into rats, glomerular overexpression of TGF-ß as well as its receptors, TGF-ßRI, -ßRII, and -ßRIII, has been demonstrated to coincide temporally with the peak of mesangial cell proliferation (8,35,40). In this study, we therefore confined our analyses to day 7, i.e., the time point at which maximal mesangial expansion occurs in the anti–Thy 1.1 glomerulonephritis induced by monoclonal antibody OX-7. Because the regulation of the biologic activity of TGF-ß is extremely complex (41), we also attempted to obtain more direct evidence for TGF-ß activity in vivo by analyzing intracellular molecules that are induced upon TGF-ß signaling, namely the members of the Smad family. We could demonstrate a constitutive renal expression of Smad7 and, for the first time, of Smad2 and P-Smad2, which was augmented during mesangioproliferative nephritis and again peaked around day 7 in the anti–Thy 1.1 glomerulonephritis. In contrast to the predominant glomerular endothelial expression of Smad2 during glomerulonephritis, glomerular expresssion of Smad7 in the nephritic state was mainly located to the mesangium. Very recently, constitutive renal Smad7 expression has also been demonstrated by Uchida et al. (34), who, in contrast to our study, noted no up-regulation of its expression during experimental mesangioproliferative glomerulonephritis. The apparent difference between the data of Uchida et al. and our observations likely results from the different animal model used in this study and different staining techniques. Instead of specific nuclear staining during immunohistology with the anti-Smad2 antibody, we mainly noted cytoplasmic and sometimes overall cellular staining. This phenomenon is similar to c-myc oncoprotein, another nuclear factor, and might depend on tissue fixation conditions (42). However, specific nuclear staining of activated Smad2 was noted with the anti–P-Smad2 antibody. The constitutive activation of Smad2 in some cells in normal kidneys is consistent with the low expression level of TGF-ß1 and its receptors in normal individuals. Apart from TGF-ß, the only other known inducer of Smad2 is activin (43). Other inducers of Smad7 are activin and bone morphogenetic protein, all members of the TGF-ß superfamily (43). Very recently, it has been described that activin, like TGF-ß, is overexpressed in the mesangium during the course of anti–Thy1.1 nephritis (44). Thus, our demonstration that Smad2 and Smad7 are overexpressed in anti–Thy1.1 nephritis may result from both TGF-ß and activin signaling. With this limitation in mind, we assessed the effects of PDGF-B antagonism on the various components of the TGF-ß system.
The central finding of this study was that highly specific antagonism of PDGF-B in experimental mesangioproliferative nephritis did not affect the glomerular expression of TGF-ß1 mRNA and protein, the mRNA of its receptors TGF-ßRI and TGF-ßRII, and TGF-ßRII protein. In addition, the glomerular overexpression of Smad2 and Smad7, and, more important, phospho-Smad2, was also not affected by PDGF-B antagonism. Although, as noted above, the overexpression of Smad2 and Smad7 is not absolutely specific for TGF-ß activity in vivo, the lack of an effect exerted by the PDGF-B aptamer strongly suggests that TGF-ß downstream signaling was not affected by the PDGF antagonism.
Currently available data have implied that in the anti–Thy1.1 model, TGF-ß and PDGF-B act serially in the evolution of mesangioproliferative changes. Our complete failure to demonstrate effects of PDGF-B antagonism on components of the TGF-ß system leads to the conclusion that PDGF-B does not act upstream but rather downstream of TGF-ß under the conditions of this study. However, because we cannot formally exclude the possibility that PDGF-B and TGF-ß might even act independently of each other in vivo, the final evidence for this conclusion should come from in vivo TGF-ß antagonism studies in glomerulonephritis and the analysis of the PDGF system under these conditions. What is the potential therapeutic implication of the present findings? Specific antagonism of PDGF-B in adult life apparently is safe. Thus, mice transgenic for a circulating PDGF antagonist (the extracellular domain of the PDGF ß-receptor), which was produced starting in late embryogenesis and adulthood only, showed no phenotypic abnormalities (45). Furthermore, both experimental renal studies (46), as well as phase I and II studies with orally available PDGF-B antagonists in tumor patients, have shown little toxicity (47). In the case of TGF-ß, no such data are presently available. Rather, it has been shown that TGF-ß, in addition to its profibrotic role, has strong immunosuppressive activity and that mice deficient in TGF-ß die of a multifocal inflammatory disease as soon as maternal transfer of TGF-ß ceases (48). Furthermore, in contrast to the established role of TGF-ß in mediating glomerular matrix accumulation, its relevance for the regulation of mesangial cell proliferation is less clear. At least in vitro, TGF-ß can act as a mesangial mitogen at low concentrations but inhibits mesangial cell growth at higher levels (49) and might thereby even limit pathologic mesangial cell proliferation in vivo. Finally, in contrast to antagonism of PDGF-B, no study so far has demonstrated that inhibition of TGF-ß in the anti–Thy1.1 model can provide a long-term benefit that will extend beyond the short-term inhibition of matrix accumulation. Given these considerations, antagonism of PDGF-B appears to represent a safe therapeutic approach, because it does not affect the very complex TGF-ß system and the rationale for inhibiting PDGF-B in mesangioproliferative disease is strengthened.
|
Acknowledgments |
|---|
|
References |
|---|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
This article has been cited by other articles:
 |
|
 |
|
  J. Floege, F. Eitner, and C. E. Alpers A New Look at Platelet-Derived Growth Factor in Renal Disease J. Am. Soc. Nephrol., January 1, 2008; 19(1): 12 - 23. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
P. Boor, A. Konieczny, L. Villa, A.-L. Schult, E. Bucher, S. Rong, U. Kunter, C. R.C. van Roeyen, T. Polakowski, H. Hawlisch, et al. Complement C5 Mediates Experimental Tubulointerstitial Fibrosis J. Am. Soc. Nephrol., May 1, 2007; 18(5): 1508 - 1515. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. C. Banas, W. T. Parks, K. L. Hudkins, B. Banas, M. Holdren, M. Iyoda, T. A. Wietecha, J. Kowalewska, G. Liu, and C. E. Alpers Localization of TGF-{beta} Signaling Intermediates Smad2, 3, 4, and 7 in Developing and Mature Human and Mouse Kidney J. Histochem. Cytochem., March 1, 2007; 55(3): 275 - 285. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. R.C. van Roeyen, F. Eitner, S. Martinkus, S. R. Thieltges, T. Ostendorf, D. Bokemeyer, B. Luscher, J. M. Luscher-Firzlaff, J. Floege, and P. R. Mertens Y-Box Protein 1 Mediates PDGF-B Effects in Mesangioproliferative Glomerular Disease J. Am. Soc. Nephrol., October 1, 2005; 16(10): 2985 - 2996. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 K. Rodgers, B. McMahon, D. Mitchell, D. Sadlier, and C. Godson Lipoxin A4 Modifies Platelet-Derived Growth Factor-Induced Profibrotic Gene Expression in Human Renal Mesangial Cells Am. J. Pathol., September 1, 2005; 167(3): 683 - 694. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Lassila, K. Jandeleit-Dahm, K. K. Seah, C. M. Smith, A. C. Calkin, T. J. Allen, and M. E. Cooper Imatinib Attenuates Diabetic Nephropathy in Apolipoprotein E-Knockout Mice J. Am. Soc. Nephrol., February 1, 2005; 16(2): 363 - 373. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 H. Fukasawa, T. Yamamoto, A. Togawa, N. Ohashi, Y. Fujigaki, T. Oda, C. Uchida, K. Kitagawa, T. Hattori, S. Suzuki, et al. Down-regulation of Smad7 expression by ubiquitin-dependent degradation contributes to renal fibrosis in obstructive nephropathy in mice PNAS, June 8, 2004; 101(23): 8687 - 8692. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. Ma, T. Matsusaka, H. Yang, H. Kawachi, F. Shimizu, Y. Isaka, E. Imai, V. Kon, and I. Ichikawa Local Actions of Endogenous Angiotensin II in Injured Glomeruli J. Am. Soc. Nephrol., May 1, 2004; 15(5): 1268 - 1276. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. Ostendorf, C. R.C. van Roeyen, J. D. Peterson, U. Kunter, F. Eitner, A. J. Hamad, G. Chan, X.-C. Jia, J. Macaluso, G. Gazit-Bornstein, et al. A Fully Human Monoclonal Antibody (CR002) Identifies PDGF-D as a Novel Mediator of Mesangioproliferative Glomerulonephritis J. Am. Soc. Nephrol., September 1, 2003; 14(9): 2237 - 2247. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. A. Aben, D. A. Hoogervorst, L. C. Paul, M. C. Borrias, N. A. Noble, W. A. Border, J. A. Bruijn, and E. de Heer Genes Expressed by the Kidney, but Not by Bone Marrow-Derived Cells, Underlie the Genetic Predisposition to Progressive Glomerulosclerosis after Mesangial Injury J. Am. Soc. Nephrol., September 1, 2003; 14(9): 2264 - 2270. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. R. White, S. Shan, C. P. Rusconi, G. Shetty, M. W. Dewhirst, C. D. Kontos, and B. A. Sullenger Inhibition of rat corneal angiogenesis by a nuclease-resistant RNA aptamer specific for angiopoietin-2 PNAS, April 29, 2003; 100(9): 5028 - 5033. [Abstract] [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||
