ARTICLE |
Correspondence to: Jeffrey L. Barnes, Dept. of Medicine, Div. of Nephrology, University of Texas Health Science Center, 7703 Floyd Curl Drive, San Antonio, TX 78284.
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Summary |
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In this study we examined if an association exists between expression of an alternatively spliced "embryonic" fibronectin isoform EIIIA (Fn-EIIIA) and -smooth muscle actin (
-SMA) in the maturing and adult rat kidney and in two unrelated models of glomerular disease, passive accelerated anti-glomerular basement membrane (GBM) nephritis and Habu venom (HV)-induced proliferative glomerulonephritis, using immunohistochemistry and in situ hybridization. Fn-EIIIA and
-SMA proteins were abundantly expressed in mesangium and in periglomerular and peritubular interstitium of 20-day embryonic and 7-day (D-7) postnatal kidneys in regions of tubule and glomerular development. Staining was markedly reduced in these structures in maturing juvenile (D-14) kidney and was largely lost in adult kidney. Expression of Fn-EIIIA and
-SMA was reinitiated in the mesangium and the periglomerular and peritubular interstitium in both models and was also observed in glomerular crescents in anti-GBM nephritis. Increased expression of Fn-EIIIA mRNA by in situ hybridization corresponded to the localization of protein staining. Dual labeling experiments verified co-localization of Fn-EIIIA and
-SMA, showing a strong correlation of staining between location and staining intensity during kidney development, maturation, and disease. Expression of EIIIA mRNA corresponded to protein expression in developing and diseased kidneys and was lost in adult kidney. These studies show a recapitulation of the co-expression of Fn-EIIIA and
-SMA in anti-GBM disease and suggest a functional link for these two proteins. (J Histochem Cytochem 47:787797, 1999)
Key Words: fibronectin, alternative splicing, smooth muscle actin, mesangium, glomerulonephritis, interstitial nephritis, fibrosis
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Introduction |
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Activation of mesenchymal cells has been associated with a switch to an -smooth muscle actin (
-SMA) phenotype during proliferation and fibrosis in a variety of disease settings (
-SMA (
Recent interest has centered on a role for fibronectin (Fn), particularly an isoform containing an extra domain EIIIA (Fn-EIIIA), as a mediator of mesenchymal cell activation. The functions of the EIIIA domain are not known. However, its close proximity to the RGDS cell binding domain suggests that this isoform has specific functional roles (
Fn protein has been detected in glomeruli and the interstitium in developing kidney decreasing in intensity during maturation (-SMA localizes in mesangial and peritubular structures during kidney development but is lost in adult kidney (
-SMA expression during fibrosis, suggesting that these two proteins may be associated in tissues undergoing high rates of remodeling. However, the studies listed above examined localization of either Fn or
-SMA alone and did not examine if these two proteins co-localize or follow the same course of expression. Moreover, expression of Fn-EIIIA isoform in renal disease has been examined (
-SMA expression have not been determined. Similarly, it is not known if the Fn-EIIIA isoform and
-SMA co-localize and follow the same course of expression during renal maturation. Because the Fn-EIIIA isoform may have an important role in cell activation in the kidney during nephrogenesis and remodeling, we examined the course of expression of Fn-EIIIA mRNA and the co-localization of these two proteins in embryonic, maturing, and adult kidney and in two unrelated models of renal disease characterized by mesangial cell proliferation, interstitial nephritis, and/or glomerular crescents. The results showed that Fn-EIIIA and
-SMA co-localize and follow the same course of expression during kidney development and maturation and that a recapitulation of co-expression occurs in the mesangium and interstitium during renal disease.
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Materials and Methods |
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Embryonic, Juvenile, and Adult Kidney
To examine the course of expression of Fn-EIIIA and -SMA during kidney maturation, kidneys were obtained from 20-day embryos just before birth (rat gestation is 22 days), 7- (D-7) and 14-day (D-14) postnatal juveniles, and 68-week adult SpragueDawley rats (Charles River; Raleigh, NC). Kidney tissue was sliced and immediately frozen in liquid nitrogen, and stored in cryogenic tubes at -70C for subsequent immunohistochemistry and in situ hybridization.
Induction of Anti-glomerular Basement Membrane (GBM) Nephritis
Anti-GBM Antibody.
Glomeruli were isolated from SpragueDawley rat kidneys by differential sieving and GBM was purified according to the methods of
Protocol
An accelerated nephrotoxic nephritis was induced according to the methods of
Proliferative Glomerulonephritis Induced by Habu Venom (HV)
To examine an association between Fn-EIIIA and -SMA in lesions in a model of nonimmune glomerular disease, five rats were injected with HV as previously reported (
Immunohistochemical Localization of Fn-EIIIA and -SMA Proteins
Localization of Fn-EIIIA and -SMA was assessed by immunofluorescence and immunoperoxidase histochemistry using mouse monoclonal antibodies (MAbs) specific for the alternatively spliced extra domain (EIIIA) of cellular Fn (clones 3E2, Sigma and IST-9, Serotec; Harlan Bioproducts for Science, Indianapolis, IN). Mouse anti-human
-SMA MAb clone 1A4 was obtained from Sigma. Acetone-fixed frozen sections (6 µm) were treated as previously described (
Dual Label Immunohistochemistry
To verify co-localization of EIIIA and -SMA, dual label immunohistochemistry was employed utilizing two separate fluorescence tags. Tissue sections of representative kidneys of D-7 juveniles, anti-GBM, and 72-hr HV experiments were incubated with anti-Fn-EIIIA antibody followed by an affinity-purified FITC-labeled donkey anti-mouse IgG adsorbed with IgG derived from multiple species for dual labeling (Chemicon International).
-SMA was detected by direct immunostaining utilizing a Cy3-labeled mouse MAb (Sigma). Sections were washed with PBSBSA between all antibody incubations. In addition, sections were incubated with normal nonimmune mouse IgG immediately before Cy3anti-
-SMA to prevent potential binding of this labeled primary to the localized FITC-labeled second anti-mouse IgG antibody. Sections were viewed and photographed using an Olympus Research microscope equipped for epifluorescence using excitation and bandpass filters optimal for either FITC or Cy3. Sections incubated with anti Fn-EIIIA and FITCsecond antibody viewed with the Cy3 filter set and Cy3anti-
-SMA viewed with the FITC filter set were negative, indicating efficient barrier filtration of cross-illumination from the opposing fluorochromes.
In Situ Hybridization
Synthesis of riboprobe, tissue preparation, in situ hybridization and autoradiography were identical to methods used previously (-SMA mRNA that is specific for
-SMA transcript (
Preparation of Riboprobes
Linearized cDNA was transcribed in vitro using a Riboprobe system II kit (Promega; Madison, WI) according to the manufacturer's instructions. Either SP6 or T7 RNA polymerase and [35S]-uridine-5'-(a-thio)-triphosphate (1300 Ci/mMol; New England Nuclear, Boston, MA) were included in the reaction mixture to generate [35S]-labeled antisense and sense riboprobes. The reaction mixture was incubated for 60 min at 40C, and then the DNA template was removed by digestion with 0.5 U RNase-free DNase, followed by removal of unincorporated nucleotides by phenolchloroform extraction and ethanol precipitation. RNA probes (activity approximately 4 x 106 CPM/µl) were stored at -70C and used within 3 days.
Tissue Preparation
Frozen sections (6 µm) were cut and collected on aminosilaneglutaraldehyde-treated slides, then fixed for 20 min in 4% paraformaldehyde in 0.01 M PBS, pH 7.4. The sections were washed twice in PBS, dehydrated through a graded series of ethanols, air-dried, and used immediately for in situ hybridization.
Tissue Hybridization
In situ hybridization procedures were performed as previously described, involving prehybridization, hybridization, and removal of nonspecifically bound probe. Prehybridization steps included treatment with 0.2 N HCl, proteinase K (1 µg/ml), and acetic anhydride to block background and enhance probe penetration. Twenty-five µl of hybridization mixture containing 50% formamide, 10% dextran sulfate, 10 mM dithiothreitol, 0.1 M Tris-HCl, pH 7.5, 0.1 M NaPO4, 0.3 M NaCl, 50 mM EDTA, 1 x Denhardt's solution, 0.2 mg/ml yeast tRNA, and 2 x 105 cpm of 35S-labeled riboprobe was applied to each section and covered with a siliconized coverslip. Hybridizations with EIIIA probes were performed in a sealed humid chamber for 18 hr at 50C. -SMA probes were very sticky, possibly due to a high content of G-C (75%) in the first half of the strand, and were hybridized at 58C. Excess probe was removed by washing slides in TE buffer, treatment with RNase A to decrease nonspecific background activity, and rinsing in 2 x SSC. Sections were dehydrated in graded ethanols, air-dried, and immersed in the dark in Kodak NTB-2 photographic emulsion (EastmanKodak; Rochester, NY). After air-drying the sections were exposed for 23 weeks at 4C. The emulsion was developed and sections were stained with hematoxylin and eosin for subsequent bright- and darkfield microscopic analysis.
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Results |
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Embryonic, Juvenile, and Adult Kidney
Expression of Fn-EIIIA and -SMA is very similar in the renal parenchyma in the late embryo and early developing kidney, showing a nearly parallel localization of these two proteins in the glomerular mesangium and peritubular interstitium. Interstitial expression of both proteins also showed a parallel reduction of expression in the maturing and adult kidney, but glomerular
-SMA expression appeared to be preferentially reduced relative to Fn-EIIIA at the D-14 timepoint and beyond. Maturation of the metanephric parenchyma occurs in an outward direction from the interior towards the outer aspect of the cortex, with newly developing structures in the most peripheral aspect of the kidney and more mature structures deeper within the cortex. The pattern of expression of Fn-EIIIA and
-SMA protein followed this course, showing strongest intensity of staining in the peritubular and periglomerular interstitial mesenchymal cells and in the glomerular mesangium (Figure 1A and Figure 1B) in developing cortex in 20-day embryos and in the outermost aspects of the cortex in D-7 kidneys (Figure 1C and Figure 1D). Staining of Fn-EIIIA and
-SMA in more mature structures in the inner aspects of the cortex in D-7 kidneys showed less intensity of staining (Figure 1C, Figure 1D, Figure 2A, and Figure 2B). Staining for both Fn-EIIIA and
-SMA in D-14 kidneys was substantially reduced and showed weak but evenly distributed staining of peritubular and periglomerular structures throughout the cortex (Figure 1E and Figure 1F). Glomeruli expressed Fn-EIIIA and
-SMA in D-14 kidneys. However, staining intensity of
-SMA diminished, particularly in more mature glomeruli, towards the inner cortex. In adult kidneys, staining for Fn-EIIIA (Figure 1G) was lost in the peritubular and periglomerular interstitium, but the glomerular mesangium retained weak staining. Expression of
-SMA (Figure 1H) was entirely lost in the peritubular interstitium and glomerular mesangium throughout the kidney cortex in adult cortex. Dual labeling experiments verified a close correlation of Fn-EIIIA and
-SMA staining in peritubular and glomerular structures in maturing (D-7) kidney (Figure 2A and Figure 2B). However, renal parenchyma destined to become arterial and arteriolar structures in embryonic tissue, as well as arteries and arterioles in maturing and adult kidney, showed a departure from the parallel staining pattern and stained intensely for
-SMA but weakly for Fn-EIIIA (Figure 1C1H).
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Anti-GBM Nephritis
Anti-GBM nephritis was characterized by a mild mesangial proliferative glomerulonephritis, glomerular crescents, and focal areas of interstitial nephritis characterized by tubular atrophy and interstitial expansion. Expression of Fn-EIIIA and -SMA protein was evident in all areas of disease and showed a distribution similar to that described for developing kidney, with strong staining in the periglomerular and peritubular interstitium and the mesangium (Figure 2C, Figure 2D, and Figure 3A3D). Glomerular crescents also stained strongly for Fn-EIIIA and
-SMA (Figure 3A and Figure 3B). Co-localization of Fn-EIIIA and
-SMA staining was verified by dual label immunofluorescence microscopy, showing a correlation between location, staining intensity, and severity of lesions in peritubular interstitium (Figure 2C and Figure 2D) and glomeruli.
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HV-induced Glomerulonephritis
Administration of HV results in an accelerated proliferative glomerulonephritis characterized by mesangiolysis, development of microaneurysms, and resulting in mesangial proliferative lesions by 72 hr after injection (-SMA (Figure 2E, Figure 2F, Figure 3E, and Figure 3F). Periglomerular and peritubular structures stained weakly for Fn-EIIIA and
-SMA (Figure 2E, Figure 2F, Figure 3E, and Figure 3F). Dual label immunofluorescence verified a co-localization of both proteins in all lesions examined (Figure 2E and Figure 2F).
In Situ Hybridization
Expression of Fn-EIIIA and -SMA mRNA corresponded to the localization of their respective proteins in embryonic, maturing, adult, and diseased kidneys (Figure 4). Message for Fn-EIIIA was observed in the interstitial mesenchyme and glomeruli, primarily in the deep cortex of 20-day embryos (Figure 4A). It became most concentrated in these same structures in the outer developing cortex of D-7 kidneys (Figure 4B) and was virtually lost in 2-week (Figure 4C) and adult rats. Similarly, Fn-EIIIA mRNA was detected in glomerular crescents and mesangium (Figure 4D) and in periglomerular and peritubular interstitium in areas of interstitial nephritis in anti-GBM rats (Figure 4E). Glomerular micronodules in kidneys from rats with HV-induced nephritis (Figure 4F) and, to a lesser extent, periglomerular and peritubular structures also showed enhanced expression of Fn-EIIIA mRNA. Sense controls showed negligible background staining.
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Probes used for the detection of -SMA mRNA were sticky (see Materials and Methods) and had a high degree of background staining, overshadowing the detail of peritubular expression of
-SMA message. However, specific message was detected above background in areas of high cellular activity, such as the outer aspect of the kidney cortex in D-7 postnatal kidney (Figure 4G), glomerular crescents (Figure 4H), and in HV-induced glomerular micronodules (Figure 4I), identical to areas of abundant expression of Fn-EIIIA mRNA and their respective proteins, as described above.
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Discussion |
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These studies largely show a co-expression of Fn-EIIIA and -SMA in embryonic and maturing rat kidneys and a recapitulation of expression in two unrelated models of renal disease. Expression of Fn-EIIIA and
-SMA was negligible or absent in adult renal parenchyma. However, a spatial and temporal association between these proteins was evident at sites of high cellular activity and activation during kidney development. Both proteins were expressed in the peritubular interstitium and glomerular mesangium, with staining intensity following the course of cortical development and a parallel reduction in expression during maturation. Fn-EIIIA mRNA was confined to the interstitium, in contrast to developing and maturing tubules, indicating that this Fn isoform is not synthesized by the tubular epithelium and is not a component of mature tubular basement membrane. Instead, Fn-EIIIA may be expressed by mesangial cells and myofibroblasts or their precursors and as a provisional matrix for developing mesenchymal structures, and may be required for capillary growth and glomerulogenesis.
A recapitulation of Fn-EIIIA and -SMA expression was observed during renal disease, with a co-expression of these proteins in the periglomerular and peritubular interstitium (by myofibroblasts) and in glomerular mesangium, similar to the areas of expression described during kidney development and maturation. A co-localization of Fn-EIIIA and
-SMA was also observed in glomerular crescents in anti-GBM nephritis. The cell types in crescents that may express
-SMA have not been identified but are believed to be myofibroblasts (
-SMA in discrete tissue structures in three different conditions of cellular remodeling (nephrogenesis, proliferative glomerulonephritis, and interstitial disease) suggest that these two proteins are tightly linked and share common functional roles required for remodeling.
Activation of various mesenchymal cells is associated with a switch to an -SMA-positive phenotype. Recent findings indicate that several cell types, such as liver fat-storing cells (Ito cells), breast stromal cells, fibroblasts, brain pericytes, and glomerular mesangial cells, do not express
-SMA in normal adult tissue or in primary culture. However, prolonged culture or exposure to growth factors activates these cells and elicits the expression of this cytoskeletal protein (
-SMA expression, suggesting that extracellular matrix interactions are important in cell activation (
-SMA-negative but can be stimulated to express
-SMA when plated on Fn-EIIIA-fusion protein or endothelial cell-derived Fn-EIIIA, an interaction that could be inhibited by blocking with specific antibody to the EIIIA domain (
-SMA are temporally and spatially associated in kidney maturation and disease.
Other alternatively spliced isoforms, such as EIIIB, may also have functional roles in embryogenesis and disease (-SMA was abundant (
A functional role for Fn-EIIIA in cell activation and a switch to an -SMA phenotype have not yet been defined. Remodeling during wound repair or after injury involves cellular behaviors including cell migration, proliferation, and synthesis of extracellular matrix, all of which Fn has been shown to influence (
-SMA has been related to mesangial cell proliferation (
-SMA parallels mesangial and Ito cell proliferation and fibrogenesis (
We have previously characterized a model of proliferative glomerulonephritis, induced by HV, by a distinct temporal course involving mesangial cell migration, proliferation, and extracellular matrix synthesis (-SMA phenotype appeared to be related to mesangial cell synthesis of Fn-EIIIA and coincided with expression of
-SMA, proliferation, and matrix synthesis, suggesting that autocrine synthesis of Fn-EIIIA by mesangial cells has specific functions during the course of glomerular remodeling. Interestingly, Fn-EIIIA was expressed in early HV-induced glomerular lesions before mesangial cell expression of
-SMA (
-SMA expression by fibroblasts during granulation tissue evolution in wound healing.
-SMA induction by transforming growth factor-ß1 (TGF-ß1). TGF-ß1 differentially regulates the expression of Fn-EIIIA in fibroblasts (
-SMA in a variety of mesenchymal cells in culture (
-SMA expression.
These studies show that Fn-EIIIA largely follows a parallel co-expression with -SMA in several settings of remodeling, including embryonic, maturing, and diseased kidney. An exact role for alternatively spliced Fn-EIIIA in glomerular cell activation (expression of
-SMA) and cell function (migration, proliferation, matrix synthesis, and hypertrophy) has not been determined and remains the focus of current research.
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Acknowledgments |
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Supported by NIH grant DK38758 from the National Institutes of Health (NIDDK), by the Office of Research and Development, Medical Research Service, Department of Veterans Affairs, and by the Southern Arizona Foundation.
We thank Dr George Henderson (Department of Medicine, UTHSCSA) for providing embryonic kidneys for this project. We also thank Drs Richard Hynes, and Gabriel Gabbiani for their generous gifts of cDNA probes to detect Fn-EIIIA and -SMA mRNA, respectively.
Received for publication October 7, 1998; accepted January 12, 1999.
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Literature Cited |
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![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
Alonso J, GomezChiarri M, Ortiz A, Seron D, Condom E, LopezArmada M, Largo R, Barat A, Egido J (1996) Glomerular up-regulation of EIIIA and V120 fibronectin isoforms in proliferative immune complex nephritis. Kidney Int 50:908-919[Medline]
Alpers CE, Hudkins KL, Gown AM, Johnson RJ (1992) Enhanced expression of "muscle-specific" actin in glomerulonephritis. Kidney Int 41:1134-1142[Medline]
Alpers CE, Pichler R, Johnson RJ (1996) Phenotypic features of cortical interstitial cells potentially important in fibrosis. Kidney Int 49:S28-31
Atkins RC, NikolicPaterson DJ, Song Q, Lan HY (1996) Modulators of crescentic glomerulonephritis. J Am Soc Nephrol 7:2271-2278[Abstract]
Barnes JL (1989) Glomerular localization of platelet secretory proteins in mesangial proliferative lesions induced by Habu snake venom. J Histochem Cytochem 37:1075-1082[Abstract]
Barnes JL, Abboud HE (1993) Temporal expression of autocrine growth factors corresponds to morphological features of mesangial proliferation in Habu snake venom-induced glomerulonephritis. Am J Pathol 143:1366-1376[Abstract]
Barnes JL, Hastings RR, De La Garza MA (1994a) Sequential expression of cellular fibronectin by platelets, macrophages, and mesangial cells in proliferative glomerulonephritis. Am J Pathol 145:585-597[Abstract]
Barnes JL, Hevey KA (1991) Glomerular mesangial cell migration: response to platelet secretory products. Am J Pathol 138:859-866[Abstract]
Barnes JL, Hevey KA, Hastings RR, Bocanegra RA (1994b) Mesangial cell migration precedes proliferation in Habu snake venom-induced glomerular injury. Lab Invest 70:460-467[Medline]
Barnes JL, Mitchell RJ, Torres ES (1995a) Expression of plasminogen activator-inhibitor-1 (PAI-1) during cellular remodeling in proliferative glomerulonephritis in the rat. J Histochem Cytochem 43:895-905
Barnes JL, Torres ES, Mitchell RJ, Peters JH (1995b) Expression of alternatively spliced fibronectin variants during remodeling in proliferative glomerulonephritis. Am J Pathol 147:1361-1371[Abstract]
Berndt A, Kosmehl H, Mandel U, Gabler U, Luo X, Celeda D, Zardi L, Katenkamp D (1995) TGFß and bFGF synthesis and localization in Dupuytren's disease (nodular palmar fibromatosis) relative to cellular activity, myofibroblast phenotype and oncofetal variants of fibronectin. Histochem J 27:1014-1020[Medline]
Borsi L, Castellani P, Risso AM, Leprini A, Zardi L (1990) Transforming growth factor-ß regulates the splicing pattern of fibronectin messenger RNA precursor. FEBS Lett 261:175-178[Medline]
Boukhalfa G, Desmouliere A, Rondeau E, Gabbiani G, Sraer JD (1996) Relationship between alpha-smooth muscle expression and fibrotic changes in human kidney. Exp Nephrol 3:241-247
Brown LF, Dubin D, Lavigne L, Logan B, Dvorak HF, Van De Water L (1993) Macrophages and fibroblasts express embryonic fibronectins during cutaneous wound healing. Am J Pathol 142:793-801[Abstract]
Carey AV, Carey RM, Gomez RA (1992) Expression of -smooth muscle actin in the developing kidney vasculature. Hypertension 19:II168-175[Medline]
DeLuca DJ, Konieczkowski M, Sedor JR (1993) -smooth muscle cell actin and mesangial cell cytodifferentiation: matrix-adherent cells retain in vivo-like gene expression. J Am Soc Nephrol 4:649A
Desmouliere A, Geinoz A, Gabbiani F, Gabbiani G (1993) Transforming growth factor-ß1 induces -smooth muscle cell actin expression in granulation tissue myofibroblasts and in quiescent and growing cultured fibroblasts. J Cell Biol 122:103-111[Abstract]
Elger M, Drenckhahn D, Nobiling R, Mundel P, Kriz W (1993) Cultured rat mesangial cells contain smooth muscle alpha-actin not found in vivo. Am J Pathol 142:497-509[Abstract]
El Nahas AM, MuchanetaKubara EC, Zhang G, Adam A, Goumenos D (1996) Phenotypic modulation of renal cells during experimental and clinical renal scarring. Kidney Int 49:S23-27
ffrenchConstant C (1995) Alternative splicing of fibronectinmany different proteins but few different functions. Exp Cell Res 221:261-271[Medline]
ffrenchConstant C, Hynes RO (1988) Patterns of fibronectin gene expression and splicing during cell migration in chicken embryos. Development 104:369-382[Abstract]
ffrenchConstant C, Hynes RO (1989) Alternative splicing of fibronectin is temporally and spatially regulated in the chicken embryo. Development 106:375-388[Abstract]
ffrenchConstant C, Van De Water L, Dvorak HF, Hynes RO (1989) Reappearance of an embryonic pattern of fibronectin splicing during wound healing in the adult rat. J Cell Biol 109:903-914[Abstract]
Glass WF, Karns LR, Haney LB (1997) Smooth muscle -actin expression and hypertrophy in cultured human mesangial cells. J Am Soc Nephrol 8:515A
Glass WF, Teng PR, Haney LB (1996) Extracellular matrix distribution and hillock formation in human mesangial cells in culture without serum. J Am Soc Nephrol 7:2230-2243[Abstract]
Hynes RO (1990) Fibronectins. New York, Springer-Verlag
Jarnagin WR, Rockey DC, Koteliansky VE, Wang S-S, Bissell DM (1994) Expression of variant fibronectins in wound healing: cellular source and biological activity of the EIIIA segment in rat hepatic fibrogenesis. J Cell Biol 127:2037-2048[Abstract]
Johnson RJ, Floege J, Yoshimura A, Iida H, Couser WG, Alpers CE (1992) The activated mesangial cell: a glomerular "myofibroblast"? J Am Soc Nephrol 2:S190-197[Abstract]
Johnson RJ, Iida H, Alpers CE, Majesky MW, Schwartz SM, Pritzl P, Gordon K, Gown AM (1991) Expression of smooth muscle cell phenotype by rat mesangial cells in immune complex nephritis. Alpha-smooth muscle actin is a marker of mesangial cell proliferation. J Clin Invest 87:847-858[Medline]
Kliem V, Johnson RJ, Alpers CE, Yoshimura A, Couser WG, Koch KM, Floege J (1996) Mechanisms involved in the pathogenesis of tubulointerstitial fibrosis in 5/6-nephrectomized rats. Kidney Int 49:666-678[Medline]
Kocher O, Gabbiani G (1987) Analysis of -smooth-muscle actin mRNA expression in rat aortic smooth-muscle cells using a specific cDNA probe. Differentiation 34:201-209[Medline]
Kuhn C, McDonald JA (1991) The roles of the myofibroblasts in idiopathic pulmonary fibrosis. Ultrastructural and immunohistochemical features of sites of active extracellular matrix synthesis. Am J Pathol 138:1257-1265[Abstract]
Lan HY, Paterson DJ, Atkins RC (1991) Initiation and evolution of interstitial leukocytic infiltration in experimental glomerulonephritis. Kidney Int 40:425-433[Medline]
Meezan E, Hjelle T, Brendel K, Carlson EC (1975) A simple, versatile, nondisruptive method for the isolation of morphologically and chemically pure basement membranes from several tissues. Life Sci 17:1721-1732[Medline]
Milani S, Herbst H, Schuppan D, Stein H, Surrenti C (1991) Transforming growth factors ß1 and ß2 are differentially expressed in fibrotic liver disease. Am J Pathol 139:1221-1229[Abstract]
Mounier F, Foidart J-M, Gubler M-C, Beziau A, Lacoste M (1986) Distribution of extracellular matrix glycoproteins during normal development of human kidney. An immunohistochemical study. Lab Invest 54:394-401[Medline]
Ng Y-Y, Fan J-M, Mu W, NikolicPaterson DJ, Huang T-P, Chang W-C, Atkins RC, Lan HY (1998) Involvement of glomerular epithelial-myofibroblast transdifferentiation (GEMT) in the development of glomerular crescents. J Am Soc Nephrol 9:505A
Nickeleit V, Zagachin L, Nishikawa K, Peters JH, Hynes RO, Colvin RB (1995) Embryonic fibronectin isoforms are synthesized in crescents in experimental autoimmune glomerulonephritis. Am J Pathol 147:965-978[Abstract]
Paul JI, Schwarzbauer JE, Tamkun JW, Hynes RO (1986) Cell-type-specific fibronectin subunits generated by alternative splicing. J Biol Chem 261:12258-12265
Peters JH, Chen G, Hynes RO (1996) Fibronectin isoform distribution in the mouse. II. Differential distribution of the alternatively spliced EIIIB, EIIIA, and V segments in the adult mouse. Cell Adhesion Commun 4:127-148[Medline]
Peters JH, Hynes RO (1996) Fibronectin isoform distribution in the mouse. I. The alternatively spliced EIIIB, EIIIA, and V segments show widespread codistribution in developing mouse embryo. Cell Adhesion Commun 4:103-125[Medline]
Peters JH, Trevithick JE, Johnson P, Hynes RO (1995) Expression of the alternatively spliced EIIIB segment of fibronectin. Cell Adhesion Commun 3:67-89[Medline]
Rockey DC, Boyles JK, Gabbiani G, Friedman SL (1992) Rat hepatic lipocytes express smooth muscle actin upon activation in vivo and in culture. J Submicrosc Cytol Pathol 24:193-203[Medline]
Sappino A-P, Schurch W, Gabbiani G (1990) Differentiation repertoire of fibroblastic cells: expression of cytoskeletal proteins as marker of phenotypic modulations. Lab Invest 63:144-161[Medline]
Schlaepfer DD, Hunter T (1996) Signal transduction from the extracellular matrixa role for the focal adhesion protein-tyrosine kinase FAK. Cell Struct Funct 21:445-450[Medline]
SchmittGraff A, Desmouliere A, Gabbiani G (1994) Heterogeneity of myofibroblast phenotypic features: an example of fibroblastic cell plasticity. Virchows Arch 425:3-24[Medline]
Schwarzbauer JE (1991) Alternative splicing of fibronectin: three variants, three functions. Bioessays 13:527-533[Medline]
Schwarzbauer JE, Paul JI, Hynes RO (1985) On the origin of species of fibronectin. Proc Natl Acad Sci USA 82:1424-1428[Abstract]
Serini G, BochatonPiallat M-L, Ropraz P, Geinoz A, Borsi L, Zardi L, Gabbiani G (1998) The fibronectin domain ED-A is crucial for myofibroblastic phenotype induction by transforming growth factor-ß1. J Cell Biol 142:873-881
Tang WW, Van GY, Qi M (1997) Myofibroblast and 1(III) collagen expression in experimental tubulointerstitial nephritis. Kidney Int 51:926-931[Medline]
Tuchweber B, Desmouliere A, BochatonPiallat ML, BubbiaBrandt L, Gabbiani G (1996) Proliferation and phenotypic modulation of portal fibroblasts in the early stages of cholestatic fibrosis in the rat. Lab Invest 74:265-278[Medline]
Xia P, Culp LA (1995) Adhesion activity in fibronectin's alternatively spliced domain EDa (EIIIA): complementarity to plasma fibronectin functions. Exp Cell Res 217:517-527[Medline]
Yamamoto T, Noble NA, Cohen AH, Nast CC, Hishida A, Gold LI, Border WA (1996) Expression of transforming growth factor-beta isoforms in human glomerular diseases. Kidney Int 49:461-469[Medline]
Yamamoto T, Noble NA, Miller DE, Border WA (1994) Sustained expression of TGF-ß1 underlies development of progressive kidney fibrosis. Kidney Int 45:916-927[Medline]
Zhang D, Flanders KC, Phan SH (1995) Cellular localization of transforming growth factor-ß expression in bleomycin-induced pulmonary fibrosis. Am J Pathol 147:352-361[Abstract]