| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
a INSERM U407, Centre Hospitalier Lyon-Sud, 69495 Pierre-Bénite cédex, France
b Laboratoire d'Hématologie, Centre Hospitalier universitaire, La Tronche, BP 217, 38043 Grenoble cédex 9, France
 |
ABSTRACT |
|---|
 TOP ABSTRACT INTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
|---|
|
INTRODUCTION |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
|---|
Hypothetically, these structuring and restructuring events are regulated by a set of proteases and antiproteases, reviewed elsewhere [9]. They also probably involve complex cross-talk between the different testicular cell populations [8, 10–12].
Among the proteases present in the seminiferous tubules are the plasminogen activators (PAs). PAs are highly specific serine proteases that convert latent plasminogen into the active protease plasmin. Two types of PA have been described, the urokinase type (uPA) and the tissue type (tPA) [13, 14]. The two are inhibited specifically by plasminogen activator inhibitor-1 (PAI-1) [15]. Previously, it has been demonstrated that Sertoli cells secreted PA, primarily of the uPA type, and, under FSH stimulation, of the tPA type [16, 17], whereas peritubular cells secreted PAI-1 [18, 19]. It was then hypothesized that cell-cell interactions between these two cell types regulate net protease activity within the seminiferous tubules [19–21].
First, however, PAs are known to be secreted on the basal and apical sides of the Sertoli junctional complexes [22]. These complexes constitute the main element of the blood-testis barrier. Second, PAI-1 of peritubular cell origin is synthesized in the basal compartment, and third, the blood-testis barrier prevents the passage of molecules such as PAI-1 between the two compartments. Therefore PAI-1 of peritubular origin cannot counteract the apical Sertoli production of PA. We thus investigated whether PAI-1 could be secreted by cultured Sertoli cells.
|
MATERIALS AND METHODS |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
|---|
Dulbecco's Modified Eagle medium (DMEM)-Ham's F-12 was obtained from Life Technologies (Grand Island, NY). Hyaluronidase, trypsin, amiloride, and dibutyryl cAMP were from Sigma Chemical Co. (St. Louis, MO). Ovine FSH (NIH FSH o-S19; FSH activity: biological potency of 94xNIH-oFSH-S1) was kindly provided by the National Hormone and Pituitary Distribution Program (NIDDK, Bethesda, MD). Human recombinant basic fibroblast growth factor (bFGF) was from Preprotech Inc. (Canton, MA). Transforming growth factor ß1 (TGFß1) purified to homogeneity from human platelets was a generous gift of Dr. Hendricks (CHU Sart Tilman, Liège, Belgium). Nitrocellulose membranes were from Amersham France (Les Ulis, France). Centricon 10 concentrators were from Amicon (Beverly, MA). Grade L fibrinogen was obtained from Kabi (Stockholm, Sweden). All electrophoresis supplies were from Bio-Rad Laboratories (Richmond, CA). Goat anti-human melanoma tPA antibody was obtained from Biopool (Umea, Sweden). The rat PAI-1 (1060) and the rabbit anti-rat PAI-1 IgG (1062) were from American Diagnostics (Greenwich, CT). Goat anti-rabbit IgG was from Dako (Trappes, France). [
-32P]deoxycytidine triphosphate (dCTP; 3000 Ci/mM) was from ICN (Orsay, France). Collagenase-dispase and restriction enzymes were purchased from Boehringer-Mannheim (Mannheim, Germany). The RNA extraction and DNA labeling kits, and the RNA ladder were from Promega (Madison, WI). All other chemicals were analytical grade and purchased from Sigma. Human PAI-1, rat TGFß1, and rat glyceraldehyde 3 phosphate dehydrogenase (GAPDH) cDNA clones were kindly provided by Drs. L.R. Lund (The Finsen Laboratory, Copenhagen, Denmark), S.W. Quian (Laboratory of Chemoprevention, Bethesda, MD), and J.M. Blanchard (Faculté des Sciences, Montpellier, France), respectively. Elutriation was performed using a rotor Beckman JE-6 (Fullerton, CA). Scanning densitometric analysis was performed using the Bioimage scanner (Millipore, Saint Quentin, France).
Cell Preparation
Sertoli cells and peritubular cells were isolated from 20-day-old rats and cultured at 32°C in a humidified atmosphere of 5% CO2 as previously described [23, 24]. Briefly, decapsulated testes were minced, then subjected to sequential enzymatic treatment and washes with collagenase-dispase (0.05%), hyaluronidase (0.1%), and collagenase-dispase (0.05%) at 32°C for 30 min each. Between enzymatic treatment and washes, cells were allowed to sediment by gravity. The final Sertoli cell suspension was seeded in a 20-cm2 Petri dish at a ratio of 4.106 viable cells. They were cultured in serum-free culture medium supplemented with gentamicin (20 mg/L). On Day 4 of culture, dishes were exposed to a hypotonic treatment [25] to remove contaminating germ cells. Alkaline phosphatase (a marker for peritubular myoid cells [26]) is used routinely to detect peritubular myoid cells. We found that alkaline phosphatase-positive cells were approximately 1% and 3–5% of the total cell population in 1- and 5- or 6-day-old Sertoli cell cultures, respectively (data not shown); thus, a Sertoli cell culture should contain more than 95% Sertoli cells.
Peritubular cells were collected in the supernatant of the first collagenase-dispase digestion. Cells were filtered through a 20-µm nylon screen and cultured at 32°C in the culture medium supplemented with 10% fetal calf serum (FCS). After 1 h, cells were washed to remove contaminating Sertoli cells and germ cells. Peritubular cells were further cultured for 1 or 6 days, with medium containing 10% FCS replenished every other day. RNA extraction was performed in 1- and 6-day-old cultured peritubular cells.
Spermatogenic cells were isolated from adult rat testes by trypsinization. The resulting crude germ cell population (containing germ cells from all developmental steps) was submitted to a centrifugal elutriation using a rotor Beckman JE-6, as described previously [27, 28]. Two fractions enriched at 80–85% with pachytene spermatocytes and early spermatids, and a third fraction enriched at 75–80% with residual bodies were harvested. The purity of cell types was assessed as previously described [28, 29]. After collection, the different cell populations were processed for RNA.
Cell Treatment and Sample Harvest
On Day 5 post-plating (unless stated otherwise), Sertoli cells were treated with different products, as described in Results. Thereafter culture media were collected, and cells were scraped from the dishes. Culture media were concentrated 10 times using Centriprep (cut-off at 10 kDa; Amicon). Cells were either lysed in a Tris buffer solution (0.5 M, pH 8.2) containing 0.5% Triton X-100 for zymography or in guanidinium thiocyanate for RNA extraction.
Zymographic Analysis
SDS-PAGE zymography was carried out as previously described [30], using 40 µl of concentrated sample. After electrophoresis, the 10% polyacrylamide gel was washed in 2.5% Triton X-100 for 1 h, and rinsed in distilled water. Fibrinolytic activity was revealed by placing the gel on a plasminogen fibrin agarose underlay and incubating it at 37°C for 16 h. For photographic purposes, the underlays were washed, dried, and stained with Coomassie blue dye. Molecular weight calibration was performed using known molecular weight standards run under the same conditions, together with human tPA and uPA. In the first series of experiments, we initially determined the PA specificity either by incorporating a polyclonal anti-tPA antibody (80 µg/ml) into the fibrin layer or by adding amiloride (1 mM) to identify uPA [30].
Isolation of RNA and Northern Blot Hybridization
Total RNA was isolated using acid-guanidinium thiocyanate-phenol-chloroform extraction in a single-step procedure as reported elsewhere [31]. The polyadenylated (poly[A]+) RNA was isolated using the Promega polyA tract messenger RNA (mRNA) isolation system. The probes used for the hybridization were a 1.2-kilobase (kb) EcoRI-Bgl II fragment of the human PAI-1 complementary DNA (cDNA), a 0.98-kb HindIII-Xba I rat TGFß1 cDNA, and a 1.3-kb rat glyceraldehyde 3 phosphate dehydrogenase cDNA (GAPDH). Probes were labeled using the Promega random-primed DNA labeling kit (specific activity, 109 disintegrations per minute/µg DNA). Northern blot analysis was performed as previously described in detail [24]. Briefly, total RNA (20 µg by A260) or poly(A)+ (3 µg) from each sample extracted was size-fractionated on 1.2% agarose-2.2 M formaldehyde gels and transferred to nitrocellulose membranes using 10-strength saline sodium citrate (single-strength SSC is 0.15 M NaCl, 0.015 M sodium citrate, pH 7.0). Filters were prehybridized, hybridized, and washed as previously described [24]. A 0.24- to 9.5-kb Promega RNA ladder was used to determine the size of the transcripts.
Western Blots
SDS-PAGE and Western blotting were carried out as described previously [32]. Primary antibody was a rabbit anti-rat PAI-1 IgG (dilution, 1:200). Secondary antibody was a goat anti-rabbit IgG (dilution, 1:500) conjugated to alkaline phosphatase. A rat PAI-1-positive control, prestained molecular weight standards, and 20 µl of the concentrated samples to be analyzed were loaded onto the SDS-PAGE gels. Under these conditions, PAI-1 migrated as a doublet band—a major band of 49 kDa and a minor band of 46 kDa—as reported previously [33].
Data Analysis
The band densities obtained in Western and Northern blotting analyses were determined by scanning densitometric analysis using the Bioimage scanner. Data obtained by scanning the Western blots were normalized using purified rat PAI-1 as a standard. The amount of RNA in each lane of each Northern blot was internally standardized within a blot by assessing the amount of GAPDH mRNA per lane. All experiments were repeated at least three times with separate cell preparations, using triplicate dishes. Significance of the results was determined using ANOVA statistical analysis. Data are presented as the mean ± SEM. Differences were accepted as significant at p < 0.05.
|
RESULTS |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
|---|
We first performed a zymographic analysis, assuming that if PAI-1 was a biologically active molecule in Sertoli cells, then it should attach to tPA and form a complex. PA activity in Sertoli cell culture media (Fig. 1a) was present in 3 bands: 1) a band migrating around 45 kDa corresponding to uPA (as inhibited by amiloride); 2) a weak band migrating at 70 kDa corresponding to tPA (as inhibited with an antiserum anti-tPA); 3) a complex migrating around 120 kDa. This complex was tPA-related because it was inhibited by an antiserum raised against tPA (not shown). The molecular weight of 120 kDa was consistent with the formation of a 1:1 molar complex of PAI-1 (46–49 kDa) and tPA (70 kDa). In cell lysates, the complex was not present (Fig. 1b). Exposure of cells to FSH for 24 h induced a decrease in the intensity of the lytic band corresponding to the tPA-PAI-1 complex (Fig. 1a). It also stimulated the tPA and slightly inhibited the uPA bands as previously observed [16, 17, 34]. Similar data have been observed in two other separate experiments.
|
Sertoli Cells Contained the PAI-1 Transcript
By Northern blotting, using 6-day-old cultured peritubular and Sertoli cells and a human PAI-1 cDNA probe, we detected a signal at 3- to 3.2-kb in peritubular cells as expected, and in Sertoli cells. No signal was observed in germ cells although poly(A)+ RNA was used (Fig. 2). The signal had the same intensity in peritubular cells and in Sertoli cells. It should be noted that cultured Sertoli and peritubular cells displayed similar GAPDH expression. By contrast, the level of GAPDH expression in germ cells is approximately 3-fold lower than Sertoli or peritubular cell GAPDH expression [24].
|
To further insure that the observed PAI-1 transcript present in Sertoli cell cultures did not result from peritubular cells contaminating the preparations, we prepared Sertoli cells and peritubular cells from the same 20-day-old rats. Next we determined the number of alkaline phosphatase-positive cells in the Sertoli cell cultures on Day 1 (beginning of the experiment) and Days 5–6 (end of the experiment) post-plating. At the same time, total RNA was extracted from Sertoli and peritubular cell cultures, and analyzed by Northern blot. Results presented in Figure 3 indicated that on Day 1 post-plating, peritubular cells contained 6.5-fold (p < 0.001) more PAI-1 transcripts than did Sertoli cells. No statistical differences were observed on Day 6 post-plating between the two cell types (confirming Fig. 2). In the meantime, alkaline phosphatase-positive cells were approximately 1% and 3–5% of the total cell population in 1-day-old and in 5- to 6-day-old Sertoli cell cultures (not shown). Results shown in Figure 3 also indicated that PAI-1 mRNA levels were 3.4-fold (p < 0.01) higher in 6-day-old cultured Sertoli cells than in 1-day-old cultures. By contrast, PAI-1 mRNA levels in peritubular cells decreased by 2-fold (p < 0.05) between Day 1 and Day 6 of culture. These data were obtained in 3 separate cell preparations, and a representative experiment is shown in Figure 3.
|
PAI-1 Transcripts Accumulated in Sertoli Cells with Duration of Culture
PAI-1 transcripts have been shown to augment in vitro in a variety of cell lines and primary cell cultures tested [15]. In addition, TGFß1 is known to accumulate in vitro [35] and to be an inducer of PAI-1 [15, 19, 36]. We thus extracted RNA from freshly isolated Sertoli cells, and from Sertoli cells cultured for 1, 4, and 6 days. Data presented in Figure 4 show that PAI-1 mRNA levels were 10 times more abundant in a 6-day-old culture than in freshly isolated cells (p < 0.001). Concomitantly, we observed a time-dependent increase of the TGFß1 signal. The mRNA levels were 4.6-times higher in a 6-day-old culture than in freshly isolated cells (p < 0.001; Fig. 4). These data were obtained in 4 separate cell preparations, and a representative experiment is shown in Figure 4.
|
PAI-1 Was Up-Regulated by TGFß1 and bFGF in Sertoli Cell Cultures
We next analyzed whether the addition of exogenous TGFß1 could influence PAI-1 in Sertoli cells. We also tested bFGF, an angiogenic factor known to stimulate PAI-1 [15, 20, 36]. We observed that exposure of Sertoli cells to TGFß1 (2 ng/ml) or bFGF (10 ng/ml) for 8 h modified the steady-state PAI-1 mRNA levels (Fig. 5A). TGFß1 and bFGF were found to double PAI-1 mRNA levels (p < 0.01 and p < 0.05, respectively). Effects of bFGF and TGFß1 were observed in 6 and 8 separate experiments, respectively. A representative experiment is shown in Figure 5A.
|
We also performed Western blotting experiments 1) to determine whether PAI-1 expressed by Sertoli cells migrated at 49 and 46 kDa as previously described with purified rat PAI-1 [33], and 2) to determine the effects of bFGF and of TGFß1 at the protein level. By Western blotting, two proteins that migrated at 49 and 46 kDa were observed in Sertoli cell-conditioned media. This doublet comigrated with purified rat hepatoma cell line PAI-1 (Fig. 5B). No bands were observed in Sertoli cell lysates (not shown). Exposure of Sertoli cells for 24 h to TGFß1 (2 ng/ml) or to bFGF (10 ng/ml) enhanced PAI-1 antigen secretion 2-fold (p < 0.05) and 2.2-fold (p < 0.05), respectively (Fig. 5B). These results were obtained in three separate Sertoli cell preparations, with a representative experiment shown.
FSH Regulated the Expression of Sertoli Cell PAI-1
We also analyzed the FSH dependency of PAI-1 expression in Sertoli cell cultures, as Sertoli cells are the only targets for FSH so far described [37, 38]. Exposure of Sertoli cells to FSH (50 or 100 ng/ml) for 8 h decreased PAI-1 mRNA levels by 2.9-fold (p < 0.05) and 3.4-fold (p < 0.01), respectively. Note that these two doses of FSH induced no statistically different responses in terms of PAI-1 mRNA levels. FSH action was mimicked by dibutyryl (db) cAMP, a cAMP analogue. We observed that dbcAMP (0.1 mM) inhibited PAI-1 mRNA levels 16.7-fold (p < 0.01) after 8 h of exposure (Fig. 6A). Effects of FSH and dbcAMP were observed in 8 and 9 separate occasions, respectively. A representative experiment is shown in Figure 6A. Action of FSH and of dbcAMP were also detected by Western blotting. FSH (100 ng/ml; 24 h) and dbcAMP (0.1 mM; 24 h) reduced PAI-1 levels by approximately one third (p < 0.01) and one half (p < 0.01), respectively. These results were obtained in three separate Sertoli cell preparations, with a representative experiment shown in Figure 6B.
|
To further study the inhibitory role of FSH, Sertoli cells were exposed continuously to FSH (50 ng/ml) from Day 1 post-plating to Day 7 of culture (end of the experiment). Total RNA was extracted on Days 0, 2, 5, and 7, and analyzed by Northern blots. Data presented in Figure 7 indicated that FSH significantly reduced (p < 0.01) the time-dependent accumulation of PAI-1 transcripts in cultured Sertoli cells.
|
|
DISCUSSION |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
|---|
Our studies indicate that cultured Sertoli cells secreted a PAI-1 protein that migrated, by Western blotting, as a doublet of 46 and 49 kDa as previously observed with purified PAI-1 from a rat hepatoma cell line [33]. The protein was detected by zymography, where it attached to tPA, indicating that it was biologically active. By Northern blotting, Sertoli cells were found to contain a transcript that hybridized with a PAI-1 cDNA probe. The transcript migrated at 3–3.2 kb, which is the size reported in the literature for rodents [15]. It was not present in germ cells. Comparison of the mRNA levels of PAI-1 expressed between peritubular cells and Sertoli cells (the two recovered from 20-day-old rats) established that PAI-1 was also a Sertoli cell product and not the sole consequence of peritubular cells producing PAI-1 and still contaminating (although weakly) the Sertoli cell preparations. In addition, we observed that PAI-1 transcripts accumulated in cultured Sertoli cells throughout a 6-day culture period, a feature that has been reported in other cell types such as endothelial cells [15, 35], but not in peritubular cells (this study). One explanation may be that peritubular cells, which actively proliferate in vitro (in contrast to Sertoli cells), lose their differentiated status and transform into fibroblasts with time in culture. This will be the subject of further investigation.
We also analyzed the action of FSH, as Sertoli cells are the only targets for FSH so far identified [3, 37, 38]. We found that FSH inhibited the tPA/PAI-1 complex, PAI-1 antigen secretion, and PAI-1 mRNA levels. FSH probably acted through the cAMP protein kinase-A pathway, since its effect was mimicked by dbcAMP. Furthermore, FSH significantly reduced the time-dependent accumulation of PAI-1 mRNA levels, suggesting that in vivo PAI-1 might be down-regulated by FSH. This would explain the low levels of expression observed in freshly isolated Sertoli cells, together with the fact that freshly isolated Sertoli cells are contaminated by an average of 10% germ cells, which do not express PAI-1. Our data on FSH action are consistent with PAI-1 down-regulated by FSH in rat granulosa cells (the female counterpart of Sertoli cells) and with the reported inhibition of PAI-1 by cAMP analogues [15]. However, they differed from those reported previously on the hormonal regulation of PAI-1 in monkey [39] and mouse [40] Sertoli cells. Indeed, it was found that FSH stimulated, whereas cAMP analogues inhibited, PAI-1. This discrepancy remains unclear. One explanation may be that the authors of the two papers [39, 40] used a less purified FSH (FSH-s17, FSH activity 20xNIH-FSH-S1) than we did (FSH-s19, FSH activity 94xNIH-FSH-S1). Indeed, one potential contaminant of FSH is bFGF, and bFGF stimulates PAI-1 (as shown in this study). In addition, the authors did not mention the percentage of contaminating germ cells, and it is known that germ cells alter Sertoli cell responsiveness to FSH [29]. Finally, there may be interspecies differences, like those concerning PAI-1 distribution. Indeed, the authors observed no PAI-1 immunostaining in monkey peritubular cells [39], contrasting with data reported on rat peritubular cells [9].
In addition to the systemic control of PAI-1, we showed that TGFß1 and bFGF significantly up-regulated immunoreactive PAI-1 and PAI-1 mRNA levels in cultured Sertoli cells. TGFß1 and bFGF are two known potent inducers of PAI-1 in a variety of cell lines or primary cell cultures [15,36]. Such growth factor action appears to be compatible with a physiological context because 1) bFGF and TGFß1 are secreted locally, with Sertoli cells being one source [4,5]; 2) the doses used are well within the dissociation constant (Kd) of the high-affinity receptors described for these ligands [41, 42]; 3) Sertoli cells express the high-affinity receptors [5, 24, 43].
Since Sertoli cells can apparently synthesize the two PAs and PAI-1, it is important to determine the nature of the signal(s) directing them to produce PA or PAI-1. One candidate may be the tandem TGFß1 and FSH. TGFß1 is known to favor the synthesis of matrix components and of protease inhibitors [15, 35, 36], and to decrease FSH-induced tPA production in rat Sertoli cells [19]. FSH stimulates tPA [16] and decreases the integrity of the seminiferous tubule barrier [9]. In addition, our data showed 1) opposite effects between these two molecules on PAI-1 gene expression and 2) a time-dependent accumulation of PAI-1 transcripts, concomitant with an accumulation of TGFß1 transcripts, but reduced by a prolonged exposure to FSH. Basic FGF may be included in this model. It can activate TGFß secreted in a latent form in endothelial cells [44], and in testis: 1) FSH stimulates bFGF expression [45] and the mRNA levels of FGFR-1 (a high-affinity receptor for bFGF) [24], and 2) bFGF enhances FSH responsiveness in terms of PA secretion [46]. It remains to be established that induction of PA and PAI-1 by bFGF in Sertoli cells occurs on a different time scale.
Determining whether the in vitro data presented here reflect a potential physiological role of PAI-1 in the male gonad function requires further studies. Undoubtedly, upon culturing on plastic, cells adapt to the in vitro conditions. Precedents exist showing that specific parameters like transferrin expression for Sertoli cells [47] or PAI-1 expression for endothelial cells [15] gradually increase with time or passage in culture. With regard to our in vitro data, it is likely that, upon culturing, Sertoli cell PAI-1 expression is enhanced (by comparison to the PAI-1 mRNA levels detected in freshly isolated Sertoli cells) as a result of at least two mechanisms: a suppression of the inhibition probably exerted by FSH in vivo, and a stimulation by TGFß1, which classically accumulates when cells are cultured on plastic [35]. Nonetheless, the great value of studies on cell lines lies in the fact that detailed information can be obtained about the intracellular mechanism of action of various regulatory agents.
With regard to the testicular physiology, it should be remembered that two major restructuring events, translocation and spermiation, have been proposed to be dependent on PA secretion. This hypothesis is based on the fact that these two events occur at stages VII–VIII of the cycle in the rat, at which PA secretion is at its greatest [17, 48]. Since peritubular cells produce PAI-1 basally and PAI-1 cannot cross the blood-testis barrier, PAI-1 of peritubular cell origin probably counteracts Sertoli cell PA secreted basally [9, 22]. By contrast, it may be suggested that Sertoli cell PAI-1 acts in the adluminal compartment 1) to limit extracellular proteolysis during processes of translocation and spermiation, and thereby 2) to prevent rupture of the Sertoli cell barrier. However, it is likely that the different proteases and antiproteases identified in testis [9] exert overlapping functions. This would explain why mice with a single deficiency in either PAI-1, uPA, tPA [49], uPA-receptor [50], or 2-macroglobulin (a potent antiprotease secreted by Sertoli cells, with a wide spectrum of activity) [51] were born normal in appearance, survived to adulthood, and produced offspring.
In conclusion, we demonstrated that rat cultured Sertoli cells express PAI-1. It is up-regulated at the protein and mRNA level by TGFß1 and bFGF, and down-regulated by FSH via the cAMP protein kinase A pathway. The role of Sertoli cell PAI-1 might be to aid in restricting proteolysis once preleptotene spermatocytes have passed the barrier, and in preventing premature release of the new elongating spermatids at spermiation.
|
ACKNOWLEDGMENTS |
|---|
|
FOOTNOTES |
|---|
2 Correspondence: Brigitte Le Magueresse-Battistoni, INSERM U407, Batiment 3B, Centre Hospitalier Lyon-sud, 69495 Pierre-Bénite cédex, France. FAX: (33) 478865922; magueress{at}lsgrisn1.univ-lyon.1.fr
Accepted: April 23, 1998.
Received: November 18, 1997.
|
REFERENCES |
|---|
|
TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTSDISCUSSIONREFERENCES |
|---|
. Endocrinology 1996; 137:4243–4249.[Abstract] regulates plasminogen activator inhibitor-1 in rat testicular peritubular cells. Endocrinology 1997; 138:1097–1105.2-macroglobulin gene. J Biol Chem 1995; 270:19778–19785.This article has been cited by other articles:
|
|
 |
|
  S. Mazaud Guittot, A. Verot, F. Odet, M.-A. Chauvin, and B. le Magueresse-Battistoni A comprehensive survey of the laminins and collagens type IV expressed in mouse Leydig cells and their regulation by LH/hCG Reproduction, April 1, 2008; 135(4): 479 - 488. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. Le Magueresse-Battistoni Serine proteases and serine protease inhibitors in testicular physiology: the plasminogen activation system Reproduction, December 1, 2007; 134(6): 721 - 729. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 P Froment, M Vigier, D Negre, I Fontaine, J Beghelli, F L Cosset, M Holzenberger, and P Durand Inactivation of the IGF-I receptor gene in primary Sertoli cells highlights the autocrine effects of IGF-I J. Endocrinol., September 1, 2007; 194(3): 557 - 568. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 F. Odet, A. Verot, and B. Le Magueresse-Battistoni The Mouse Testis Is the Source of Various Serine Proteases and Serine Proteinase Inhibitors (SERPINs): Serine Proteases and SERPINs Identified in Leydig Cells Are under Gonadotropin Regulation Endocrinology, September 1, 2006; 147(9): 4374 - 4383. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R E. Ramy, A Verot, S Mazaud, F Odet, S Magre, and B Le Magueresse-Battistoni Fibroblast growth factor (FGF) 2 and FGF9 mediate mesenchymal-epithelial interactions of peritubular and Sertoli cells in the rat testis J. Endocrinol., October 1, 2005; 187(1): 135 - 147. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 D. D. Mruk and C. Y. Cheng Sertoli-Sertoli and Sertoli-Germ Cell Interactions and Their Significance in Germ Cell Movement in the Seminiferous Epithelium during Spermatogenesis Endocr. Rev., October 1, 2004; 25(5): 747 - 806. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
F. Odet, R. Guyot, P. Leduque, and B. Le Magueresse-Battistoni Evidence for Similar Expression of Protein C Inhibitor and the Urokinase-Type Plasminogen Activator System during Mouse Testis Development Endocrinology, March 1, 2004; 145(3): 1481 - 1489. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. D. Anway, J. Folmer, W. W. Wright, and B. R. Zirkin Isolation of Sertoli Cells from Adult Rat Testes: An Approach to Ex Vivo Studies of Sertoli Cell Function Biol Reprod, March 1, 2003; 68(3): 996 - 1002. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
W.-Y. Lui, W. M. Lee, and C. Y. Cheng Transforming Growth Factor-{beta}3 Perturbs the Inter-Sertoli Tight Junction Permeability Barrier in Vitro Possibly Mediated via Its Effects on Occludin, Zonula Occludens-1, and Claudin-11 Endocrinology, May 1, 2001; 142(5): 1865 - 1877. [Abstract] [Full Text]
|
|
|
|
 |
|
 J. Longin, P. Guillaumot, M.-A. Chauvin, A.-M. Morera, and B. Le Magueresse-Battistoni MT1-MMP in rat testicular development and the control of Sertoli cell proMMP-2 activation J. Cell Sci., January 6, 2001; 114(11): 2125 - 2134. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. Canipari and M. Galdieri Retinoid Modulation of Plasminogen Activator Production in Rat Sertoli Cells Biol Reprod, August 1, 2000; 63(2): 544 - 550. [Abstract] [Full Text]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
