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Endocrinology Vol. 140, No. 7 3106-3113
Copyright © 1999 by The Endocrine Society

ARTICLES

Hepatocyte Growth Factor and c-MET Are Expressed in Rat Prepuberal Testis1

A. Catizone, G. Ricci, V. Arista, A. Innocenzi and M. Galdieri

Department of Histology and Medical Embriology (A.C., G.R., V.A., A.I., M.G.), University of Rome "La Sapienza," Rome 00161, Italy; and Institute of Histology and General Embriology (M.G.), II University of Naples, Naples 80138, Italy

Address all correspondence and requests for reprints to: M. Galdieri, Dipartimento Istologia ed Embriologia Medica, Via A. Scarpa 14, Rome 00161, Italy. E-mail: galdieri{at}uniroma1.it


   Abstract
Top
 Abstract
Introduction
 Materials and Methods
 Results
 Discussion
 References
 
The hepatocyte growth factor (HGF) receptor (c-MET) is present in different mammalian tissues and transduces multiple biological effects. The HGF is known to regulate many fundamental cellular functions, such as cell growth, movement and differentiation, and is involved in embryonal morphogenesis. We have studied HGF and c-MET expression in prepuberal rat testis. c-MET gene expression was found in total testis and in homogeneous cell populations, as demonstrated by Northern blotting. In the seminiferous tubules, c-MET gene was only expressed in the myoid cells. In these cells, c-MET was detectable and constantly expressed for at least six days of culture. The interstitial tissue was also c-MET positive. The protein encoded by the MET proto-oncogene was detected in myoid cells, and HGF administration to these cells induced morphological changes in the cells. HGF expression was not detected by Northern blotting using RNA extracted from total testis. By contrast, when homogenous cell populations were used, HGF expression was detectable and exclusively localized in myoid cells. Myoid cell-conditioned medium was able to induce scattering of canine kidney epithelial (MDCK) cells, and the scatter effect of a 3-days conditioned medium was evident even after 7-fold dilution of the medium. Our findings demonstrate that HGF and its receptor are present in rat prepuberal testis. The coexpression of factor and receptor in the myoid cells suggests a new role for HGF as autocrine regulator of myoid cell function and, possibly, as regulator of mammalian testicular function.


   Introduction
Top
 Abstract
 Introduction
Materials and Methods
 Results
 Discussion
 References
 
THE MET PROTO-ONCOGENE belongs to the thyrosine kinase family of genes and codifies the hepatocyte growth factor receptor (HGFR) (1). This proto-oncogene, initially discovered as a gene able to transform normal fibroblast cell lines (2), was subsequently identified in normal cells isolated from different mammalian tissues (3). The tyrosine kinase receptors are components of the intercellular communication pathways controlling cellular growth and differentiation, as well as embryonal morphogenesis (4). The MET proto-oncogene encodes a transmembrane glycoprotein which specifically binds to the hepatocyte growth factor/scatter factor (HGF/SF) and transduces its multiple biological effects (5, 6). HGF, discovered as the factor able to induce liver regeneration, is also able to regulate morphogenesis, cellular growth, and movement (7, 8). During mouse embryonic development, c-MET is expressed in the epithelial cells of different developing organs, whereas HGF is expressed in the mesenchymal cells of the same organs (9). These findings suggest a paracrine role of HGF and indicate its function in the mesenchymal-epithelial interactions. Fibroblasts overexpressing HGF and HGFR, injected into nude mice, induce mesenchymal to epithelial conversion (10), and epithelial conversion has been obtained by treating cells isolated from mouse metanephric ridge with HGF (11). In addition, HGF has a morphogenic effect on epithelial tissues, resulting in the formation of tubules and gland-like structures in cells derived from kidney and mammary tissue (12, 13). Very few data are available concerning the HGF/HGFR system in the reproductive tract. c-MET expression has not been detected in the adult mouse testis (3), although it is present in the human testis, prostate, and seminal vesicles (14, 15). By contrast, HGF is expressed in the mouse testis and in the distal regions of the epididymis, and the high expression in the epididymis has been correlated with the acquisition of sperm motility (16). In this paper, we present evidence that in prepuberal rat testis c-MET and HGF messenger RNAs (mRNAs) are both expressed in myoid cells in a biologically active form.


   Materials and Methods
Top
 Abstract
 Introduction
 Materials and Methods
Results
 Discussion
 References
 
Animals
Wistar rats were obtained from Charles River Farms (Como, Italy). All animal studies were conducted in accordance with the principles and procedures outlined in NIH Guide for Care and Use of Laboratory Animals.

Materials
MEM, DMEM, FCS, and Random Primers DNA Labeling System were purchased from Gibco BRL Life Technologies, (Gaithersburg, MD). Collagenase was obtained from Boehringer Mannheim (Mannheim, Germany). Culture plates were purchased from Corning, Inc. (New York, NY). Biotin, Protein A-Sepharose, and all other reagents were purchased from Sigma Chemical Co. (St. Louis, MO). Hybond N+ membrane and ECL Western Blotting detection reagents were purchased from Amersham-Italia (Milan, Italy). Percoll was obtained from Pharmacia-Biotech AB (Milan, Italy).

Cell preparation and culture
Sertoli cells were prepared using 8–10 male Wistar rats, 18- to 20-day-aged as previously indicated (17). Cells were cultured in MEM for 5 days to allow cellular monolayer formation before cell utilization. Purified myoid cells were prepared according to Palombi et al. (18) from the same animals used for Sertoli cell preparation. In brief, small explants of decapsulated testes were digested for 30 min at 32 C by 0.25% trypsin in PBS to detach the interstitium. The seminiferous tubules were sedimented by gravity, and the supernatant was removed and centrifuged to sediment the interstitial cells (fraction called "interstitium"). The seminiferous tubules were treated with collagenase A (1 mg/ml) for 30 min at 32 C to detach the total peritubular cells and then sedimented again by gravity. The supernatant was removed and the tubules washed with PBS and sedimented again. The supernatant was removed, pooled with the first and centrifuged for 2 min at 40 x g. The pellet was further digested in 0,1% trypsin in PBS supplemented with 2% EDTA to obtain a single cell suspension, applied on a discontinuous Percoll gradient and centrifuged for 20 min at 800 x g at room temperature. The fraction corresponding to the myoid cells (density 1.075 g/ml) was collected and the cells were washed twice with MEM. The pellet was immediately used for RNA extraction or resuspended in MEM and plated at the desired density. The purity of the cells used for the experiments, checked by the presence of the alkaline phosphatase activity, was never lower than 94% (19).

RNA isolation and Northern blot analysis
Total RNA was extracted from cultured cells by the method of Chomczynski and Sacchi (20). The integrity of the RNA was tested through the presence of the ribosomal species in formaldehyde denaturing gels. Northern blot analysis using 30 µg of RNA in each lane was performed on 1% agarose/formaldehyde gels and transferred to Hybond-N+ membrane. Prehybridization, hybridization and washings were performed according to the conditions suggested by the supplier. The membrane was exposed on x-ray film. Rat MET (1 kb) and HGF (2.1 kb) complementary DNAs (cDNAs) (both provided by Dr. G. Gaudino) were labeled using a random primer labeling kit. Relative differences in hybridization were determined by scanning densitometry of autoradiograms. HGF and c-MET expression in total RNA was normalized to the signal for the constitutively expressed glyceraldeyde-3-phosphate dehydrogenase (GAPDH).

Scatter activity of myoid and Sertoli cell culture medium
The scatter activity of myoid cell culture medium was measured on colonies of canine kidney epithelial cells (MDCK cells) as previously described (21). A suspension of MDCK cells in DMEM supplemented with 10% FCS was prepared, and 9000 cells were plated in 24-well plates containing 0.5 ml of culture medium. Plates were incubated at 37 C. Undiluted or diluted culture medium obtained after two, three, or six days of myoid cell culture was added to the cells either at plating or after 4 h of culture. To obtain conditioned medium, 3 x 106 myoid cells were usually seeded in a 6-cm diameter Petri dish containing 3 ml of medium. As control of scatter activity HGF (30–100 U/ml) was added to the cells either at plating or after 4 h of culture. When indicated, MDCK cells were cultured without serum. Sertoli cells, prepared as indicated above, were used to obtain conditioned culture medium. After 3 or 6 days of culture, undiluted medium was tested for scatter activity.

Cell surface biotinylation and immunoprecipitation
Myoid and Sertoli cells were incubated with 0.5 mg/ml biotin in HBSS without phosphate for 30 min at 4 C. After biotinylation, both myoid and Sertoli cells were extracted as previously described (22) and cell extracts, precleaned on Protein A-Sepharose, were immunoprecipitated with a mixture of antihuman c-MET monoclonal antibodies (DN-30, DO-24, kindly provided by Dr. M. Prat), which react with different epitopes of ß chain extracellular domain (23). The immunocomplexes, eluted in Laemmli buffer (24), were subjected to gel electrophoresis under reducing conditions, transferred to nitrocellulose, and rinsed in Streptavidin-horseradish peroxidase 1:1000 in Tris-buffered saline Tween 0.1% pH 7,6 (TBS-T) for 1 h at room temperature, and then the immunoprecipitated molecules were detected by ECL reaction following the manufacturer’s instructions.

Statistical analysis
Statistical analysis was performed by Student’s t test.


   Results
Top
 Abstract
 Introduction
 Materials and Methods
 Results
Discussion
 References
 
The expression of c-MET and HGF genes was analyzed in total testes isolated from prepuberal rats using specific cDNAs (kindly provided by Dr. G. Gaudino). Northern blot hybridization showed the presence of a c-MET specific message (Fig. 1Go), and one single mRNA species was recognized at the same molecular weight of liver mRNA (9 kb). By contrast, no signal was obtained using a cDNA specific for HGF.



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  		Figure 1. Expression of HGF/SF and c-MET mRNAs in prepuberal rat liver and testis. A, Northern blot analysis was performed on 30 µg of total RNA extracted from liver (L) and total testis (TT). The same blot has been used for both hybridizations. X-ray films were exposed for 14 days for HGF hybridization, or 9 days for c-MET hybridization with intensifying screens. B, densitometric scanning of the autoradiograms. The mean ± SE of at least three experiments are reported. *, P < 0.01 vs. TT values.

 
To understand in which cell type(s) of the testis these RNAs are expressed, homogeneous cell populations of Sertoli cells and myoid cells isolated from prepuberal rats were prepared. Northern blot analysis of c-MET RNA extracted from the two cell populations and, as a positive control, from prepuberal rat liver (Fig. 2AGo) are reported. The densitometric scanning of the bands is shown in Fig. 2BGo. c-MET expression was found in both myoid cells, and the mixed cell population that we call "interstitium" (see Materials and Methods). By contrast, Sertoli cells did not express positive signals. In myoid cells, c-MET expression was also studied during culture time, and RNA extracted from noncultured cells (day 0) was compared with RNAs extracted from cells cultured for different time periods of up to 6 days (Fig. 3AGo). As shown by the densitometric analysis (Fig. 3BGo), c-MET RNA expression does not statistically change during culture time (P = not significant).



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  		Figure 2. Expression of c-MET mRNA in different cell populations isolated from prepuberal rat testis. A, Northern blot analysis was performed on 30 µg of total RNA extracted from Sertoli cells (S), myoid cells (M), interstitial cells (I), and total testis (TT). L, RNA from prepuberal rat liver. B, Densitometric scanning of the autoradiograms. The mean ± SE of at least three experiments are reported. *, P < 0.01 vs. TT values and not significant (n.s) vs. L and I values.

 


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  		Figure 3. Expression of c-MET mRNA in myoid cells cultured for different time periods. A, Northern blot analysis performed on RNA extracted from noncultured (0) or cultured myoid cells (1–2-6 days of culture). L, RNA from prepuberal rat liver. B, Densitometric scanning of the autoradiograms. The mean ± SE of three experiments are reported. P = not significant between day 0 and day 6 values.

 
To detect the presence of c-MET protein, cell surface proteins of myoid and Sertoli cells were biotinylated, and total cellular proteins were immunoprecipitated with anti c-MET monoclonal antibody obtained against c-MET extracellular domain (22). The immunoprecipitates were electrophorized under reducing conditions and the p145MET, p85MET, and p50MET molecules, corresponding to the c-MET intact ß chain, truncated ß chain, and {alpha} chain, respectively, were detected in myoid cells by Western blotting. The same molecules were absent in immunoprecipitates prepared from Sertoli cells (Fig. 4Go). An additional protein at molecular weight close to the c-Met single-chain precursor molecular weight is present in myoid cell immunoprecipitates.



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  		Figure 4. Expression of c-MET protein in myoid (M) and Sertoli cells (S). Electrophoresis on a 8% acrylamide gel of biotinylated proteins immunoprecipitated with anti-MET monoclonal antibody is shown. The numbers on the right represent the position of the standard proteins. The arrows indicate c-MET chains molecular weights.

 
Myoid cells cultured in the presence of HGF (100 U/ml) modify their morphology, changing from a round, compact (Fig. 5AGo) to an elongated, enlarged shape (Fig. 5BGo). Some of the cells acquired a fibroblast-like morphology. The described effects were evident after treatment with HGF for 16 h and persisted for at least 6 days of culture.



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  		Figure 5. Brightfield microscopy of myoid cells cultured for 24 h in the absence (A) and in the presence (B) of HGF (100 U/ml). Cells were fast-blue stained to detect alkaline-phosphatase activity. Bar, 46 µm.

 
Similar experiments were performed to better analyze HGF expression using specific cell populations. The only positive cells, among those examined, were the myoid cells (Fig. 6Go). Myoid cell HGF expression was analyzed at different culture times (Fig. 7AGo), and the results obtained indicate that RNA expression significantly increases (P < 0.05 between day 0 and day 6 values) during culture time (Fig. 7BGo).



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  		Figure 6. Expression of HGF/SF mRNA in different cell populations isolated from prepuberal rat testis. A, Northern blot analysis was performed on 30 µg of total RNA extracted from Sertoli cells (S), myoid cells (M), interstitial cells (I), and total testis (TT). L, RNA from prepuberal rat liver. B, Densitometric scanning of the autoradiograms. The mean ± SE of at least three experiments are reported. P = not significant between M vs. L values.

 


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  		Figure 7. Expression of HGF/SF mRNA in myoid cells cultured for different time periods. A, Northern blot analysis was performed on 30 µg of total RNA extracted from noncultured (0) or cultured myoid cells (1–2-6 days of culture). L, RNA from prepuberal rat liver. B, Densitometric scanning of the autoradiograms. The mean ± SE of three experiments are reported. *, P < 0.05 vs. day 0 values.

 
Conditioned media obtained from myoid cell cultures were added to cultured MDCK cells. Figure 8AGo shows the appearance of untreated MDCK cells, whereas Fig. 8BGo shows the scattered appearance of the same cells after a 16-h incubation in a 3-day conditioned medium from myoid cells. The scatter effect lasted for at least 6 days and was obtained either with media conditioned for 2, 3, or 6 days. The scatter effect was obtained both on preformed clusters of MDCK cells and on single cells that, after the addition of myoid cell culture medium, became unable to form clusters. Moreover, myoid cell-conditioned medium had the same inhibiting effect on cluster formation if cells were cultured in the absence of serum (Fig. 8CGo). Myoid cell culture medium was diluted several times, and each diluted medium tested for scatter activity. Three-day conditioned medium, at a 1:7 dilution, was still able to induce scattering of MDCK cells, which was effective on approximately 30% of the MDCK clusters, whereas at 1:3 dilution, 100% of MDCK clusters were dissociated. Sertoli cell-conditioned medium failed to have any effect on the scatter activity of MDCK cells.



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  		Figure 8. Scattering of MDCK epithelial cells induced by myoid cell conditioned medium. A, Morphological appearance of cells cultured for 16 h in DMEM additioned with 10% FCS. B, Scattering of the same cells cultured in myoid cell conditioned medium with 10% FCS added. C, Scattering of the cells cultured in myoid cell-conditioned medium without serum addition. Bar, 50 µm.

 

   Discussion
Top
 Abstract
 Introduction
 Materials and Methods
 Results
 Discussion
References
 
Rat HGF primary structure has been described, and its expression has been detected in various rat tissues, but the testis was not included in the examined tissues (25). We studied the expression of HGF and its receptor, c-MET, in the prepuberal rat testis and we report, for the first time, that HGF is expressed in the seminiferous tubules. Purified myoid cells are positive for HGF mRNA expression, whereas Sertoli cells and the interstitial cells are negative. HGF is secreted by the myoid cells in the culture medium, as demonstrated by the ability of the myoid cell-conditioned medium to induce the scattering of MDCK cells. The scatter effect was induced by medium in which myoid cells were cultured for 2 or more days and was effective both on isolated and on clustered MDCK cells. In the literature, it is known that HGF is secreted as a pro-HGF inactive form that is usually transformed into the bioactive form in the extracellular matrix by different enzymes, including both the urokinase-type and tissue-type plasminogen activators (26, 27, 28) and the coagulation factor XII (29). The observed scatter effect on MDCK cells implies that HGF present in myoid cell culture medium is of the active form, probably being activated by the plasminogen activator secreted by the myoid cells (Canipari, R., unpublished observations). The scatter effect and the inability to form clusters induced on MDCK cells by myoid cell-conditioned medium are effects similar to those previously described by Pasdar et al. (30) for MDCK cells cultured in the presence of HGF. The adhering junctions present in MDCK cells at the level of cell-to-cell contact are disassembled after HGF addition and the molecular components homogeneously redistributed along the membrane (30). Obviously, we cannot exclude that other biologically active substances secreted by the myoid cells may cooperate to induce the effects observed after myoid cell culture medium addition to MDCK cells.

We also demonstrated that HGF receptor, the product of the MET proto-oncogene, is present in the prepuberal rat testis. In the seminiferous tubules, c-MET mRNA is exclusively expressed in the myoid cells and its expression is constant for the first week of cell culture. The receptor protein subunits have been detected in myoid cells by immunoprecipitation as previously described for different cell types (22). In Sertoli cells, considered as a negative control because MET mRNA is not present, the MET antibody failed to detect any molecule except a low molecular weight species that was considered a contaminant. In conclusion, we report the presence of the HGF receptor c-MET in the rat testis. The presence of c-MET, which was undetected in the mouse testis (16), has been revealed in the human testis in the germinal cell lineage (15). In prepuberal rats testis, we found that c-MET is expressed in somatic cells and further experiments will clarify whether maturing germ cells and spermatozoa express c-MET in adult rats, thus making rodents similar to the human species.

In prepuberal rats, HGF and HGF receptor are expressed by the same somatic cell, which suggests that HGF secreted by the myoid cells has an autocrine effect. During mouse development, a paracrine effect of HGF is described, owing to the fact that HGF is produced by the mesenchymal cells and the receptor is present in epithelial cells (9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31). However, the coexpression of factor and receptor has been reported for neoplastic and normal cells (32, 33). What we found in rats makes intriguing the role exerted by extracellular matrix components in mediating HGF effects on myoid cells. It is known that peritubular myoid cells secrete glycosaminoglycans and that the secretion is regulated by hormones and by the Sertoli cell extracellular matrix (34, 35). It is also known that HGF binds to sulfoglycolipids (36) and to heparansulphate proteoglycans (37, 38), though the role of this binding is still controversial. A positive effect of heparin has been described (39) and, more recently, a negative role for HGF binding to heparansulphate has been suggested because the binding appears to be involved in the degradation of the factor (40). In our system, the extracellular matrix might modulate the effect of myoid cell-derived HGF on interstitial cells. In fact, c-MET was highly expressed in the mixed cell population we prepared from the testicular interstitial compartment. Considering the fundamental role of the glycosaminoglycan composition of the target cell surface, we can also hypothesize that the variation of the extracellular matrix regulates HGF effects on the myoid cell itself. On the other hand, as myoid cell extracellular matrix secretion is known to be regulated by platelet-derived growth factor (41), FCS (42), and retinoids (Ricci et al., paper in publication), HGF secretion and effects depend, in vivo, on a complex network of molecules controlling myoid cell metabolism and, in particular, myoid cell secretory activity.

Moreover, we believe, that our experimental system will allow us both to clarify the biological effects of HGF on myoid cells and to study the physiological role of HGF on spermatogenetic process regulation. Given that myoid cells cooperate with Sertoli cells to create the tubular wall and the microenvironment necessary for normal germ cell development, HGF may, by modulating myoid cell metabolism, indirectly regulate germ cell maturation.


   Acknowledgments
 
The autors wish to thank Drs. G. Gaudino (Piemonte Orientale University, Italy) and C. Ponzetto (Torino University, Italy) for providing, respectively, rat cDNAs probes and HGF. Dr. M. F. Di Renzo and Dr. M. Stefanini are gratefully acknowledged for the helpful suggestions.


   Footnotes
 
1 This work was supported by the grants from Ministero per l’Università la Ricerca Scientifica e Tecnologica (MURST 40% 1995 and 1996, to M.G.) and by the National Research Council (CNR 95.02941.CT14 to M. Stefanini). Back

Received August 4, 1998.


   References
Top
 Abstract
 Introduction
 Materials and Methods
 Results
 Discussion
 References
 

  1. Park M, Dean M, Kaul K, Braun MJ, Gonda MA, Wande Woude G 1987 Sequence of MET protooncogene cDNA has features characteristic of the tyrosine kinase family of growth factor receptors. Proc Natl Acad Sci USA 84:6379–6383[Abstract/Free Full Text]
  2. Cooper CS, Park M, Blair D, Tainsky MA, Huebner K, Croce CM, Vande Woude GF 1984 Molecular cloning of a new transforming gene from a chemically-transformed human cell line. Nature 311:29–33[CrossRef][Medline]
  3. Iyer A, Kmiecik TE, Park M, Daar I, Blair D, Dunn JK, Sutrave P, Ihle JN, Bodescot M, Vande Woude GF 1990 Structure, tissue-specific expression, and transforming activity of the mouse met protooncogene. Cell Growth Differ 1:87–95[Abstract]
  4. Sonnemberg E, Godecke A, Walter F, Bladt F, Birckmeier C 1991 Transient and locally restricted expression of the ros-1 protooncogene during mouse development. EMBO J 10:3693–3702[Medline]
  5. Ponzetto C, Bardelli A, Zhen Z, Maina F, dalla Zonca P, Giordano S, Graziani A, Panayotou G, Comoglio PM 1994 A multifunctional docking site mediates signaling and transformation by the hepatocyte growth factor/scatter factor receptor family. Cell 77:261–271[CrossRef][Medline]
  6. Ponzetto C, Zhen Z, Audero E, Maina F, Bardelli A, Basile ML, Giordano S, Narsimhan R, Comoglio PM 1996 Specific uncoupling of GRB2 from Met receptor. J Biol Chem 271:14119–14123[Abstract/Free Full Text]
  7. Weidner KM, Sachs M, Birchmeier W 1993 The met receptor tyrosine kinase transduces motility, proliferation, and morphogenic signals of scatter factor/hepatocyte growth factor in epithelial cells. J Cell Biol 11:145–154
  8. Hartmann G, Weidner KM, Schwarz H, Birchmeier W 1994 The motility signal of scatter factor/hepatocyte growth factor mediated through the receptor tyrosine kinase met requires intracellular action of ras. J Biol Chem 269:21936–21939[Abstract/Free Full Text]
  9. Sonnemberg E, Meyer D, Weidner KM, Birckmeier C 1993 Scatter factor/hepathocyte growth factor and its receptor, the c-MET tyrosine kinase, can mediate a signal exchange between mesenchyme and epithelia during mouse development. J Cell Biol 123:223–235[Abstract/Free Full Text]
  10. Tsarfaty I, Rong S, Resau JH, Rulong S, Pinto de Silva P, Vande Woude GF 1994 The Met proto-oncogene mesenchymal to epithelial cell conversion. Science 263:98–101[Abstract/Free Full Text]
  11. Karp SL, Ortiz-Arduan A, Li S, Neilson GE 1994 Epithelial differentiation of metanephric mesenchymal cells after stimulation with hepatocyte growth factor or embryonic spinal cord. Proc Natl Acad Sci USA 91:5286–5290[Abstract/Free Full Text]
  12. Montesano R, Matsumoto K, Nakamura T, Orci L 1991 Identification of a fibroblast-derived epithelial morphogen as hepatocyte growth factor. Cell 67:901–908[CrossRef][Medline]
  13. Soriano JV, Pepper MS, Nakamura T, Orci L, Montesano R 1995 Hepatocyte growth factor stimulates extensive development of branching duct-like structures by cloned mammary gland epithelial cells. J Cell Sci 108:413–430[Abstract]
  14. Di Renzo MF, Narsimhan RP, Olivero M, Bretti S, Giordano S, Medico E, Gaglia P, Zara P, Comoglio PM 1991 Expression of the Met/HGF receptor in normal and neoplastic human tissue. Oncogene 6:1997–2003[Medline]
  15. Depuydt CE, Zalata A, de Potter CR, van Emmelo J, Comhaire FH 1996 The receptor encoded by the human c-MET oncogene is expressed in testicular tissue and on human spermatozoa. Mol Hum Reprod 2:2–8[Abstract/Free Full Text]
  16. Naz RK, Joseph A, Lee Y, Ahmad K, Bhargava MM 1994 Expression of scatter factor/hepathocyte growth factor is regionally correlated with the initiation of sperm motility in murine male genital tract: is scatter factor/hepathocyte growth factor involved in initiation of sperm motility? Mol Reprod Dev 38:431–439[CrossRef][Medline]
  17. Galdieri M, Ziparo E, Palombi F, Russo M, Stefanini M 1981 Pure Sertoli cell culture: a new model for the study of somatic-germ cell interaction. J Androl 5:249–254
  18. Palombi F, Farini D, De Cesaris P, Stefanini M 1988 Characterization of peritubular myoid cells in highly enriched in vitro cultures. In: Cooke B, Sharpe RM (eds) The Molecular and Cellular Endocrinology of the Testis. Serono Symposia Publications, Raven Press, New York, vol 50:311–317
  19. Palombi F, Di Carlo C 1988 Alkaline phosphatase is a marker of myoid cells in culture in rat peritubular and testicular tissue. Biol Reprod 39:1101–1109[Abstract]
  20. Chomczynski P, Sacchi N 1987 Single-step method of RNA isolation by acid guanidinium thiocyanate-phenol-chloroform extraction. Anal Biochem 162:156–159[Medline]
  21. Bhargava MM, Li Y, Joseph A, Pendergast M, Hofmann R, Rosen EM, Goldberg ID 1991 Purification, characterization and mechanism of action of scatter factor from human placenta. In: Goldberg ID (ed) Cell Motility Factors. Birckhauser Verlag, Basel, pp 63–75
  22. Prat M, Crepaldi T, Gandino L, Giordano S, Longati P, Comoglio PM 1991 C-terminal truncated forms of Met, the hepatocyte growth factor receptor. Mol Cell Biol 11:5954–5962[Abstract/Free Full Text]
  23. Prat M, Crepaldi T, Pennacchietti S, Bussolino F, Comoglio PM 1998 Agonistic monoclonal antibodies against the met receptor dissect the biological responses to HGF. J Cell Sci 111:237–247[Abstract]
  24. Laemmli UK 1970 Cleavage of structural proteins during the assembly of the head of bacteriophage T4. Nature 227:680–685[CrossRef][Medline]
  25. Tashiro K, Hagiya M, Nishizawa T, Seki T, Shimonishi M, Shimizu S, Nakamura T 1990 Deduced primary structure of rat hepatocyte growth factor and expression of the mRNA in rat tissues. Proc Natl Acad Sci USA 87:3200–3204[Abstract/Free Full Text]
  26. Naldini l, Tamagnone L, Vigna E, Sachs M, Hartmann G, Birchmeier W, Daikuhara Y, Tsubouchi H, Blasi F, Comoglio PM 1992 Extracellular proteolytic clavage by urokinase is required for activation of hepatocyte growth factor/scatter factor. EMBO J 11:4825–4833[Medline]
  27. Naldini l, Vigna E, Bardelli A, Follenzi A, Galimi F, Comoglio PM 1995 Biological activation of pro-HGF (hepatocyte growth factor) by urokinase is controlled by a stoichiometric reaction. J Biol Chem 270:603–611[Abstract/Free Full Text]
  28. Mars WM, Zarnegar R, Michalopoulos GK 1993 Activation of hepatocyte growth factor by the plasminogen activators uPA and tPA. Am J Pathol 143:949–958[Abstract]
  29. Shimomura T, Miyazawa K, Komiyama Y, Hiraoka H, Naka D, Morimoto Y, Kitamura N 1995 Activation of hepatocyte growth factor by two homologous proteases, blood-coagulation factor XIIa and hepatocyte growth factor activator. Eur J Biochem 229:257–261[Medline]
  30. Pasdar M, Zhi L, Marreli M, Nguyen BT, Park M, Wong K 1997 Inhibition of junction assembly in cultured epithelial cells by hepatocyte growth factor/scatter factor is concomitant with increased stability and altered phosphorylation of the soluble junctional molecules. Cell Growth Differ 8:451–462[Abstract]
  31. Ohmichi H, Kashimizu U, Matsumoto K, Nakamura T 1998 Hepatocyte growth factor (HGF) acts as a mesenchyme-derived morphogenic factor during fetal lung development. Development 125:1315–1324[Abstract]
  32. Tsao MS, Zhu H, Giaid A, Viallet J, Nakamura T, Park M 1993 Hepatocyte growth factor/scatter factor is an autocrine factor for human normal bronchial epithelial and lung carcinoma cell. Cell Growth Differ 4:571–579[Abstract]
  33. Shiota G, Kawasaki H, Nakamura T 1996 Coexpression of hepatocyte growth factor and its receptor (c-met oncogene) in HGL4 glioblastoma cell. Oncology 53:511–516[Medline]
  34. Raychoudhury SS, Blackshaw AW, Irving MG 1993 Hormonal modulation of the interactions of cultured rat testicular Sertoli and peritubular myoid cells: effect on glicosamminoglycan synthesis. J Androl 14:9–16[Abstract/Free Full Text]
  35. Raychoudhury SS, Blackshaw AW, Irving MG 1993 Rat Sertoli cells extracellular matrix regulates glicosamminoglycan synthesis by peritubular myoid cells in vitro. Mol Reprod Dev 35:151–158[CrossRef][Medline]
  36. Kobayashi T, Honke K, Miyazaki T, Matsumoto K, Nakamura T, Ishizuka I, Makita A 1994 Hepatocyte growth factor specifically binds to sulfoglycolips. J Biol Chem 269:9817–9821[Abstract/Free Full Text]
  37. Lyon M, Gallagher JT 1994 Hepatocyte growth factor/scatter factor: a heparan sulphate-binding pleiotropic growth factor. Biochem Soc Trans 22:365–370[Medline]
  38. Lyon M, Deakin JA, Mizuno K, Nakamura T, Gallagher JT 1994 Interaction of hepatocyte growth factor with heparan sulphate. Elucidation of the major heparan sulphate structural determinants. J Biol Chem 269:11216–11223[Abstract/Free Full Text]
  39. Schwall R, Chang L, Godowski P, Kahn D, Hillan K, Bauer K, Zioncheck T 1996 Heparin induces dimerization and confers proliferative activity onto the hepatocyte growth factor antagonist NK1 and NK2. J Cell Biol 133:709–718[Abstract/Free Full Text]
  40. Hartman G, Prospero T, Brinkmann V, Ozcelik O, Winter G, Hepple J, Batley S, Bladt F, Sachs M, Birchmeier C, Birchmeier W, Gherardi E 1997 Engineered mutants of HGF/SF with reduced binding to heparan sulphate proteoglycans, decreased clearance and enhanced activity in vivo. Curr Biol 8:125–134
  41. Gnessi L, Emidi A, Scarpa S, Palleschi S, Ragano-Caracciolo M, Silvestroni L, Modesti A, Spera G 1993 Platelet-derived growth factor effects on purified peritubular myoid cells: binding cytosolic Ca2+ increase, mitogenic activity, and extracellular matrix production enhancement. Endocrinology 133:1880–1890[Abstract]
  42. Galdieri M, Ricci G 1998 Characterization of different cell population isolated from rat testis peritubular cells. Differentiation 63:13–19[CrossRef][Medline]



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