Molecular Human Reproduction, Vol. 10, No. 2, pp. 91-97, 2004
© European Society of Human Reproduction and Embryology 2004
The role of 
5ß1-integrin in the IGF-I-induced migration of extravillous trophoblast cells during the process of implantation
Departments of 1Obstetrics and Gynecology and 2Anatomy, Kyorin University School of Medicine, Mitaka, Tokyo, 181-8611, Japan and 3Department of Anatomical Sciences, Faculty of Medical Sciences, Tarbiat Modares University, 14115-111 Tehran, Iran
4 To whom correspondence should be addressed at: Department of Obstetrics and Gynecology, Kyorin University School of Medicine, Mitaka, Tokyo, 181-8611, Japan. e-mail: kabirs_m{at}yahoo.com
 |
ABSTRACT |
|---|
 Top ABSTRACT IntroductionMaterials and methodsResultsDiscussionREFERENCES |
|---|
The role of integrins in the processes of adhesion and migration makes them attractive potential participants in the complex events of embryo implantation and placentation. Recently, the role of the
vß3-integrin pathway was shown in the insulin-like growth factor-I (IGF-I)-stimulated migration of extravillous trophoblast (EVT) cells. This study was designed to investigate the role of 5ß1-integrin in this respect. Using cultured EVT cells, migration assays were carried out for IGF-I-treated or untreated cells in the presence or absence of the GRGDSP and GRGESP hexapeptides, IR3, and a blocking antibody against 5ß1-integrin. Immuno-electron microscopy and immunofluorescent staining were performed to localize the distribution of 5ß1- and vß3-integrins, Rab5a, paxillin, phospho-FAK (pFAK), and vinculin. The results showed that IGF-I-induced migration of EVT cells was abolished following treatment with GRGDSP hexapeptide, IR3, and a blocking antibody against 5ß1-integrin. Further, statistical analysis showed that the area-related numerical density of the 5ß1-integrin in the perinuclear regions was significantly higher than in the cell extensions. Immunocytochemical experiments demonstrated an up-regulation in internalization rate of 5ß1-integrin in IGF-I-stimulated EVT cells. Furthermore, 5ß1-integrin exhibited co-localization with Rab5a, but not with vß3-integrin, pFAK, paxillin, and vinculin at the focal adhesions of the EVT cells. Taken together, these findings suggest an essential role for 5ß1-integrin in IGF-I-promoted migration of EVT cells. It is possible therefore that IGF-I-induced internalization of 5ß1-integrin may be an important event during the migration of EVT cells in the complex processes of implantation and placentation.
Key words:
Key words: 5ß1-integrin/IGF-I/implantation/placentation/trophoblast migration
|
Introduction |
|---|
|
TopABSTRACTIntroductionMaterials and methodsResultsDiscussionREFERENCES |
|---|
During the process of embryo implantation, a highly migratory subpopulation of placental trophoblasts migrates and invades the maternal decidua and its vasculature to establish an adequate exchange of the key molecules (Gleeson et al., 2001). These cells arise from cytotrophoblast stem cells that undergo a change in the cell surface phenotype with the loss of
6ß1-integrin and rapid up-regulation of 5ß1- and vß3-integrins (Damsky et al., 1992). The exact role of these integrins in the processes of the embryo implantation and placentation remains unresolved. However, the significance of the interaction between 5ß1-integrin with fibronectin (FN) substrate has been implicated in several important cellular events such as embryonic development, wound healing, and tumour metastasis (Ruoslahti, 1994; Mostafavi-Pour et al., 2003). Decidual stroma is rich in FN and migrant EVT cells secrete their own extracellular matrix (ECM), in particular, FN (Aplin and Charlton, 1990; Burrows, 1996). In addition, the acquisition of 5ß1-integrin by EVT cells seems to be associated with cell mobility similar to that seen in the healing of a skin wound where the 6ß4-positive sessile keratinocytes at the periphery of a wound are transformed to the 5ß1-positive motile cells which migrate over the gap in the wound onto a substrate of FN (Grinnell, 1994).
It has been reported that first-trimester placental fibroblasts produce insulin-like growth factor-I (IGF-I), which promotes the migration of trophoblast cells in vitro (Lacey et al., 2002). There is clear evidence indicating that an interaction exists between the IGF-I receptor and integrins during cell migration (Clemmons and Maile, 2003). The role of vß3-integrin in IGF-I-induced migration of EVT cells has already been established (Kabir-Salmani et al., 2003), whereas the role of 5ß1-integrin in this context is a matter of some controversy (Damsky et al., 1994; Irving and Lala, 1995). The present study is designed to examine the significance of 5ß1-integrin in IGF-I-stimulated migration of EVT cells during the processes of embryo implantation and placentation. Furthermore, the effect of IGF-I on the expression of 5ß1-integrin and the co-localization of this integrin with the components of the focal adhesions (FA) of human EVT cells has been studied.
|
Materials and methods |
|---|
|
TopABSTRACTIntroductionMaterials and methodsResultsDiscussionREFERENCES |
|---|
Reagents
Recombinant human IGF-I was a gift from Fujisawa Pharmaceutical Co. (Japan). Monoclonal antibody against
-subunit of IGF-IR (IR3) was purchased from Calbiochem Oncogene Research Products (USA). vß3-Integrin anti-mouse monoclonal IgG and 5ß-integrin anti-goat polyclonal IgG were from Chemicon International (USA). Paxillin anti-rabbit polyclonal IgG and 5-integrin anti-goat polyclonal IgG were purchased from Santa Cruz Biotechnology (USA). Phospho-FAK anti-rabbit polyclonal IgG was from Upstate Biotechnology (USA). Vinculin monoclonal anti-mouse IgG1 was from Sigma Chemical Company (USA). AMCA-conjugated donkey anti-goat IgG was purchased from Jackson Immuno Research Laboratories Inc (USA). Alexa 568-labelled donkey anti-mouse and anti-rabbit IgG were purchased from Molecular Probes (USA). Nanogold anti-mouse, anti-rabbit and anti-goat IgG were from Nanoprobes (USA). Fibronectin (FN), FN inhibitor, Gly-Arg-Gly-Asp-Ser-Pro (RGD hexapeptide) and Gly-Arg-Gly-Glu-Ser-Pro (RGE hexapeptide) were synthesized by Iwaki Glass Co. (Japan). TAAB Epon 812, glutaraldehyde, and osmium tetraoxide were from TAAB Laboratories Equipment Ltd (UK).
Primary trophoblast cell culture
Placental tissues between 6 and 10 weeks of gestation were obtained at legal, elective termination of pregnancy. All patients gave informed consent for collection and investigational use of tissues. This study was approved by the ethics committee of Kyorin University, School of Medicine, Tokyo, Japan. EVT were obtained by the method described previously (Kabir-Salmani et al., 2003). Briefly, the tissues were rinsed several times in cold medium 199 containing streptomycin (20 mg/ml) and penicillin (500 IU/ml). Selected tissues were then cut into small pieces and any obvious blood vessels or clots, membranes, and decidual tissues were removed. Then fragments were cultured in the same medium containing 10% FBS in tissue culture flasks, pre-coated with 20 µg of FN diluted in 1 ml phosphate-buffered saline (PBS, pH 7.4). Tissues were allowed to attach to the bottom of the flasks for 30–60 min before adding the medium. After 3–5 days, unattached cells were removed and culture was continued for an additional 1–2 weeks. The medium was changed every 48 h until cells were confluent and then the cells were passaged. Passages 2–4 were used for all experiments. The identity of cells as extravillous trophoblast cells was established by immunohistochemical staining as described previously (Kabir-Salmani et al., 2003).
Cell wounding and migration assay
Cells were plated at 1.2–1.4x104/cm2 in medium 199 containing 10% FBS and allowed to grow to confluence over 3 days. Wounding was performed using a sterile razor blade to scrape cells off the culture plate, leaving a denuded area and a sharp visible demarcation line at the wound edge, as described in previous reports (Jones et al., 1996). The wounded monolayers were rinsed three times with serum-free medium 199 and were inspected immediately after wounding. Then sections of the wounds that were to be used for quantifying migration were selected according to the criteria described previously (Jones et al., 1996; Irving and Lala, 1995), marked, and numbered. The areas with technical problems such as extra lines made by razor blade, incomplete scraping or deep wounds were not selected as one of the experimental group. The cells were then incubated for 48 h with serum- free medium 199 with 0.01% bovine serum albumin (BSA) and one of the following: (i) 10 nmol/l IGF-I alone or in the presence of IR3, (ii) blocking antibody against 5ß1-integrin alone or in the presence of 10 nmol/l IGF-I, (iii) 100 µmol/l GRGDSP hexapeptide alone or in the presence of 10 nmol/l IGF-I, or (iv) 100 µmol/l GRGESP hexapeptide as a control for GRGDSP alone or in the presence of 10 nmol/l IGF-I. Before addition of IGF-I, the cells were preincubated for 30–60 min with blocking antibodies and peptides. At the end of the preincubation period, cells were >95% viable as assessed by Trypan Blue dye exclusion. Then cells were rinsed in PBS, fixed and stained using Diff-Quick kit solutions and examined under phase-contrast microscopy. Migrated EVT cells were counted in sections 1.0 mm in length; allowing a 20 µm space from the demarcation line to minimize the possible physical effects of cell movement resulting from cell proliferation. A calibrated eyepiece grid was used to determine the mean number of migrated cells. Statistical analysis was calculated by averaging a mean of 10 sections per test substance for each experiment. The number of migrated cells was expressed as mean ± SEM. Statistical significance was evaluated using analysis of variance with Scheffé’s test and P < 0.01 was considered statistically significant. The experiments were repeated at least four times in each group to assess reproducibility.
Immunocytochemistry
For immunogold transmission electron microscopy preparations, serum-starved EVT cells were incubated with serum-free medium 199 with or without 10 nmol/l IGF-I for 2 h to study the effect of IGF-I on the distribution patterns of vß3- and 5-integrins. Cells were then fixed using 4% paraformaldehyde, permeabilized with 0.5% Triton X-100, and blocked by 5% BSA for 1 h at 4°C. Thereafter, the cells were incubated overnight at 4°C with an appropriate primary antibody (anti-5ß1-integrin IgG; 1.5 µg/ml and anti-vß3-integrin IgG; 1.5 µg/ml). After washing several times with PBS, the cells were incubated overnight with their appropriate colloidal gold-conjugated anti-goat, anti-rabbit and anti-mouse IgG (using 6–12 nm gold particles). The cells were then fixed in cacodylate buffer (100 nmol/l sodium cacodylate, pH 7.2, 120 mmol/l CaCl2), containing 2.5% glutaraldehyde overnight at 4°C. After washing with cacodylate buffer, the cells were post-fixed in 1% OsO4 for 2 h, washed and dehydrated by successive 10 min incubations with 30, 50, 70, 90 and 100% ethanol. Following dehydration, the cells were detached and embedded in Epon resin. Ultrathin sections were cut using a diamond knife and the staining procedure was performed. Grids were observed using a JEM, 1010 JEOL transmission electron microscope (Tokyo, Japan) operated at 80 kV. This experiment was repeated four times in four different preparations. For morphometric analysis of immunogold-labelled integrins, 200 cells per test group were chosen randomly by an observer who was blind to the identity of these grids and four to six photomicrographs were taken from body and cell extension regions of each cell. Area-related numerical density of immunogold particles was calculated using NIH Image software (Version 1.61). Morphometric analysis was performed to quantify these data as described previously (Glasbey and Roberts, 1997). To determine the co-localization of 5-integrin with Rab5a, the same procedures were carried out.
For immunofluorescent preparations, EVT cells were cultured on FN-coated Lab-Tek chamber slides and incubated for 18–24 h with serum-free medium 199. To stimulate assembly of FA in these cells, the cells were treated with 10 nmol/l IGF-I for 30 min. Cells were then fixed and permeabilized as described above. For double-staining, the cells were incubated with the appropriate primary antibodies (anti-vinculin IgG; 1 µg/ml, anti-paxillin IgG; 1.5 µg/ml, anti-phospho-FAK IgG; 1.5 µg/ml, anti-Rab5a IgG; 1.5 µg/ml, and anti-5ß1-integrin IgG; 1.5 µg/ml) for 1–3 h at room temperature. For control, the coverslips were incubated at room temperature for 1–3 h with the same concentration of corresponding antibodies, including monoclonal anti-mouse IgG (substituted for mouse anti-vinculin), polyclonal anti-rabbit IgG (substituted for paxillin IgG, Rab5a IgG, and phospho-FAK IgG), and polyclonal anti-goat IgG (substituted for 5ß1-integrin IgG). Then cells were rinsed in PBS extensively and counter-stained with proper fluorescent-labelled secondary antibodies (Alexa 568-labelled donkey anti-mouse IgG, 1 µg/ml; FITC-labelled donkey anti-rabbit IgG, 1 µg/ml; and AMCA-labelled donkey anti-goat IgG, 1 µg/ml). After washing with PBS, rinsing in deionized water and mounting, cells were observed using an AX-80 fluorescence microscope (Olympus Optical, Japan). These experiments were repeated thee times in thee different preparations in each group.
|
Results |
|---|
|
TopABSTRACTIntroductionMaterials and methodsResultsDiscussionREFERENCES |
|---|
Migration assay
The results of the migration assays showed that the treatment with 10 nmol/l IGF-I significantly (P < 0.01) stimulated the migration of EVT cells, which was
2-fold higher than control (Figure 1). Inhibition of IGF-IR by IR3 antibody demonstrated that the number of migrated cells was significantly (P < 0.01) decreased compared with its corresponding control. The preincubation of EVT cells with a functional blocking antibody against 5ß1-integrin significantly decreased the migration of EVT cells in both IGF-I-treated and untreated cells. Moreover, the migration of IGF-I-treated EVT cells was abrogated by preincubation of these cells with GRGDSP hexapeptide but not GRGESP hexapeptide. GRGDSP hexapeptide decreased the number of migrating cells compared with its corresponding control, which was treated with GRGESP hexapeptide. These data further showed that preincubation of EVT cells with GRGESP had no effect on the migration of EVT cells compared with control serum-starved EVT cells that were incubated with serum-free medium 199.
|
Immunocytochemistry
Morphometric analysis of the distribution of gold particles over body and cell extension areas of EVT cells revealed that area-related numerical density of
5ß1-integrin is higher in the perinuclear region compared with the cell extensions and lamellipodia, whereas vß3-integrin was found to have a higher area-related numerical density in the cellular extensions compared with the cell body (Figure 2). Further, area-related numerical density of vß3-integrin in the cell extensions and lamellipodia showed a relatively higher density compared with 5ß1-integrin.
|
Semi-quantitative analysis of immunogold-labelled
5ß1-integrin in ultrathin EVT cell sections demonstrated that IGF-I treatment increased their internalization 3-fold above control (Figure 3). Aggregations of 5ß1-integrin showed co-localization with Rab5a (Figure 4), a member of the Rab subfamily small GTPases, which is considered to be one of the key regulators of intracellular transportation (Horiuchi et al., 1997).
|
|
Images from immunofluorescent staining further confirmed the co-localization of
5ß1-integrin with Rab5a in the EVT cells (Figure 4). Double-staining for 5ß1-integrin with vß3-integrin, pFAK, paxillin, and vinculin demonstrated that 5ß1-integrin did not co-exist with these components at the FA of EVT cells (Figure 5). No staining of these structures could be seen without primary antibodies in the control group (results not shown). These confocal images support the results obtained from immunogold labelling, indicating a perinuclear distribution of 5ß1-integrin, whereas vß3-integrin showed a peripheral localization corresponding to the FA.
|
|
Discussion |
|---|
|
TopABSTRACTIntroductionMaterials and methodsResultsDiscussionREFERENCES |
|---|
Explants of placental villi from first trimester pregnancy have been shown to provide an appropriate in vitro model for studying migratory events during the process of human embryo implantation and placentation (Vicovac et al., 1995). Employing propagated EVT cells in this study, the results of the migration assays exhibited an essential role for
5ß1-integrin during the migratory function of EVT cells in both control and IGF-I-treated EVT cells. This is consistent with previous studies in a variety of cell types suggesting that the binding of the 5ß1-integrin to the FN substrate enhanced cell migration and the addition of anti-5 and anti-ß1-integrin blocking antibodies inhibited the trophoblast migration on FN (Irving and Lala, 1995). Further, it has been reported that 5-integrin affects the rate of tumour metastasis (Tani et al., 2003). In another set of experiments using a villous explant organ culture assay, it has been demonstrated that treatment of EVT cells with anti-5-integrin antibody interfered with the outgrowth of EVT cell column and caused rounding of the spindle-shaped EVT cells (Aplin et al., 1999), which could indicate a loss of cell motility in these cells. In contrast to the above findings, it has been previously reported that the adhesion of trophoblast cells to FN via 5ß1-integrin generates an invasion-restraining signal. The addition of the exogenous FN to a thee-dimensional matrigel invasion assay system inhibited the trophoblast invasion, whereas the addition of the anti-5-integrin monoclonal antibody accelerated invasion (Damsky et al., 1994). These conflicting results may be due, at least in part, to the type and concentrations of different ECM proteins used in each assay system. ECM concentration has been shown to be crucial to the cellular responses, as lower concentrations of FN have been observed to support cellular migration, whereas high concentrations retarded migration (Madri et al., 1988). It is of interest that the invasiveness of the trophoblast cells in molar pregnancies is almost unrestricted and in this pre-malignant condition, villous trophoblast, which does not normally express the 5-subunit, becomes strongly positive for this subunit and thus resembles the extravillous invading trophoblast phenotype in expressing 5ß1-integrin (Bischof et al., 1993).
In our migration assay system, the GRGDSP hexapeptide and a blocking antibody against 5ß1-integrin were used to clarify the importance of the binding of 5ß1-integrin to the RGD domain of the FN substrate during the IGF-I-stimulated migration of the EVT cells. Upon treatment of EVT cells with GRGDSP hexapeptide or blocking antibody against 5ß1-integrin, the number of migrating cells showed a statistically significant reduction in both IGF-I-treated and untreated cells. This is in agreement with a previous report showing that the treatment of EVT cells with GRGDSP hexapeptide abolished IGF-II-stimulated migration of EVT cells in vitro (Irving and Lala, 1995). It is also consistent with another study that showed the importance of 5ß1-integrin binding to the RGD domain of FN during IGF-binding protein-1-stimulated migration of EVT cells (Jones et al., 1996). Considering that highly migratory tumour cells secrete RGD-containing FN into their surroundings and use it as a platform for their migration (Humphies, 1990), secretion of FN by EVT cells (Burrows et al., 1996) may suggest that these cells use the similar substrate during their integrin-dependent migration as well. Notably, binding to FN affects the terminal differentiation of EVT cells, which can influence their migration. Tenascin, an ECM protein, has been demonstrated to interfere with the attachment of EVT cells to FN (Erickson and Bourdon, 1989). Strong expression of this protein has been observed in human uterine myometrium, particularly in the areas where trophoblast migration ceased (Burrows et al., 1996). This further indicates that the binding of the migrant EVT cells to the FN substrate is essential to their migratory function.
As cell migration requires the efficient, regulated formation and breakdown of cell–ECM adhesions and integrin recycling following internalization, we next examined the effects of IGF-I on the internalization rate of 5ß1-integrin. Semi-quantitative analysis of immunogold-labelled 5ß1-integrin in the ultrathin sections of EVT cells demonstrated that IGF-I treatment increased the internalization rate of 5ß1-integrin. Furthermore, immunofluorescent staining exhibited the co-localization of 5ß1-integrin with Rab5a in EVT cells, which implies its intracellular transportation (Bucci et al., 1992). Rab5 is exclusively localized to the plasma membrane, early endosomes, and plasma membrane-derived clathin-coated vesicles (Chavrier et al., 1990; Bucci et al., 1992). Using green fluorescent protein (GFP) in living cells, 5-integrin has been seen to remain on the substrate behind the migrating cells or appeared in the vesicles that move toward the cell body where they are either degraded or recycled to the cell front for incorporation into the new adhesions (Palecek et al., 1998; Pierini et al., 2000; Laukaitis et al., 2001). The fact that prevention of integrin internalization by a calcineurin inhibitor that inhibits the cell mobility provides the best evidence to date that integrin recycling is an essential aspect of cell motility (Lawson and Maxfield, 1995). On the other hand, a biphasic relationship exists between the adhesive strength of ß1-integrins and their ability to mediate the cell movement. Cell movement increases progressively with adhesive strength, but is reduced beyond a certain point of optimal interaction (Hangan-Steinmn et al., 1999). This is why changing in the expression of 5ß1-integrin in some tumours correlates with their invasiveness (Fujita et al., 1995). Thus, we propose that the increased internalization of 5ß1-integrin following IGF-I stimulation may promote migration of EVT cells either via modulating the adhesive strength of 5ß1-integrin or though up-regulation of adhesion turnover and formation of new adhesions. The importance of the increased internalization of 5ß1-integrin in IGF-I-induced migration of EVT cells needs further study.
Considering the fact that IGF-I can stimulate the formation of the FA in several cell types (Leventhal et al., 1997; Kabir-Salmani et al., 2003), the possibility of the co-localization of 5ß1-integrin with the components of FA as integrin-based structures was studied next. Results obtained from immunofluorescent double-staining demonstrated that 5ß1-integrin was not co-localized with vß3-integrin, pFAK, paxillin or vinculin at FA of EVT cells. This is in agreement with previous reports showing that 5ß1-integrin was not detected in FA of fibroblast cells in two-dimensional culture systems (Geiger et al., 2001). Likewise, using green fluorescent protein in living migrating cells, the co-localization of 5-integrin with paxillin or -actinin was not observed (Laukaitis et al., 2001). This is in contrast to the previous report that employed a thee-dimensional culture system for fibroblastic cells and observed the co-localization of 5ß1-integrin with paxillin and FAK (Cukierman et al., 2001). More studies are required to determine the possibility of the co-existence of 5ß1-integrin with components of the EVT cells and its interaction with vß3-integrin on EVT cell surface in thee-dimensional culture system and in vivo. Emerging evidence shows that interactions between different integrins on the cell surface can strongly influence the adhesive function of individual receptors (Lishko et al., 2003; Ly et al., 2003). Considering the fact that vß3-integrin has a pivotal role in the migratory function of several cell types (Jones et al., 1996; Kabir-Salmani et al., 2003) and that 5ß1 regulates the vß3-mediated adhesion and migration (Ly et al., 2003), it is tempting to suggest that IGF-I might affect the migratory function of EVT cells though ‘crosstalk’ and activation of both 5ß1 and vß3-integrins.
In conclusion, our findings indicate that the binding of 5ß1-integrin to the RGD domain of the FN substrate is essential to the migratory event of EVT cells. We speculate that IGF-I stimulates the migration of these cells, at least in part, via modulation of 5ß1-integrin recycling by regulating its internalization.
|
Acknowledgements |
|---|
The authors would like to thank Mr Fukuda for his invaluable help in this study. This work was supported in part by Grants-in-Aid (C) 11671648 (to S.Shiokawa) from the Ministry of Education, Science and Culture (Tokyo, Japan).
|
REFERENCES |
|---|
|
TopABSTRACTIntroductionMaterials and methodsResultsDiscussionREFERENCES |
|---|
Aplin JD and Charlton AK (1990) The role of matrix macromolecules in the invasion of decidua by trophoblast. Trophoblast Res 4,139–158.
Aplin JD, Haigh T, Jones CJP, Church HJ and Vicovac L (1999) Development of cytotrophoblast columns from explanted first-trimester human placental villi: role of fibronectin and integrin 5ß1. Biol Reprod 60,82–83.
Bischof P, Redard M, Gindre P, Vassilakos P and Campana A (1993) Localization of alpha 2, alpha 5 and alpha 6 integrin subunits in human endometrium, deciduas and trophoblast. Eur J Obstet Gynecol Reprod Biol 51,217–226.[CrossRef][Web of Science][Medline]
Bucci C, Parton RG, Mather IH, Stunnenburg H, Simons K, Hoflack B and Zerial M (1992) The small GTPase rab5 functions as a regulatory factor in the early endocytotic pathway. Cell 70,715–728.[CrossRef][Web of Science][Medline]
Burrows TD, King A and Loke YW (1996) Trophoblast migration during placental implantation. Hum Reprod Update 2,307–321.
Chavrier P, Parton RG, Hauri HP, Simons K and Zerial M (1990) Localization of low molecular weight GTP binding proteins to exocytic and endocytic compartments. Cell 62,317–329.[CrossRef][Web of Science][Medline]
Clemmons DR and Maile LA (2003) Minireview: integral membrane proteins that function coordinately with the insulin-like growth factor-I receptor to regulate intracellular signaling. Endocrinology 144,1664–1670.
Cukierman E, Pankov R, Stevens DR and Yamada KM (2001) Taking cell–matrix adhesions to the third dimension. Science 294,1708–1713.
Damsky CH, Fitzgerald ML and Fisher SJ (1992) Distribution of extracellular matrix components and adhesion receptors are intricately modulated during first trimester cytotrophoblast differentiation along the invasive pathway, in vivo. J Clin Invest 89,210–222.[Web of Science][Medline]
Damsky, CH, Librach, C, Lim, K-H, Fitzgerald, ML, McMaster, MT, Janatpour, M, Zhou, Y, Logan, SK and Fisher, SJ (1994) Integrin switching regulates normal trophoblast invasion. Development 120,3657–3666.[Abstract]
Duclos S, Corsisni R and Desjardins M (2003) Remodelling of endosomes during lysosome biogenesis involves ‘kiss and run’ fusion events regulated by rab5. J Cell Sci 116,907–918.
Erickson HP and Bourdon MA (1989) Tenascin: an extracellular matrix protein prominent in specialized embryonic tissues and tumors. Annu Rev Cell Biol 5,71–92.[CrossRef][Web of Science][Medline]
Fujita S, Wartanabe M, Kubota T, Teramoto T and Kitajima M (1995) Alternation of expression in integrin ß1-subunit correlates with invasion and metastasis on colorectal cancer. Cancer Lett 9,145–149.
Geiger B, Bershadsky A, Pankov R and Yamada KM (2001) Transmembrane extracellular matrix–cytoskeleton crosstalk. Nature Rev 2,793–805.
Glasbey CA and Roberts IN (1997) Statistical analysis of the distribution of gold particles over antigen sites after immunogold labeling. J Microsc 186,258–262.[CrossRef]
Gleeson LM, Chakraborty C, Mckinnon T and Lala PK (2001) Insulin-like growth factor binding protein 1 stimulates human trophoblast migration by signaling though 5ß1 integrin via mitogen-activated protein kinase pathway. J Clin Endocrinol Metab 86,2484–2493.
Grinnell F (1994) Fibroblasts, myofibroblasts and wound contraction. J Cell Biol 124,401–404.
Hangan-Steinman D, Ho WC, Shenoy P, Chan BM and Morris VL (1999) Differences in phosphatase modulation of alpha4 beta1 and alpha5 beta1 integrin-mediated adhesion and migration of B16F1 cells. Biochem Cell Biol 77,409–420.[CrossRef][Web of Science][Medline]
Horiuchi H et al. (1997) A novel Rab5 GDP/GTP exchange factor complexed to Rabaptin-5 links nucleotide exchange to effector recruitment and function. Cell 90,1149–1159.[CrossRef][Web of Science][Medline]
Humphies MJ (1990) The molecular basis and specificity of integrin-ligand interactions. J Cell Sci 97,585–592.
Irving JA and Lala PK (1995) Functional role of cell surface integrins on human trophoblast cell migration: regulation by TGF-ß, IGF-II, and IGFBP-1. Exp Cell Res 217,419–427.[CrossRef][Web of Science][Medline]
Jones JI, Prevette T, Gockerman A and Clemmons DR (1996) Ligand occupancy of the vß3 integrin is necessary for smooth muscle cells to migrate in response to IGF-I. Proc Natl Acad Sci USA 93,2482–2487.
Kabir-Salmani M, Shiokawa S, Akimoto Y, Hasan-Nejad H, Sakai K, Nagamatsu S, Sakai K, Nakamura Y, Hosseini A and Iwashita M (2002) Characterization of morphological and cytoskeletal changes of trophoblast cells induced by insulin-like growth factor-I. J Clin Endocrinol Metab 87,5751–5759.
Kabir-Salmani M, Shiokawa S, Akimoto Y, Sakai K, Nagamatsu S, Sakai K, Nakamura Y, Lotfi A, Kawakami H and Iwashita M (2003) vß3 integrin signaling pathway is involved in insulin-like growth factor-I-stimulated human extravillous trophoblast cell migration. Endocrinology 144,1620–1630.
Lacey H, Haigh T, Westwood M and Aplin JD (2002) Mesenchymally-derived IGF-I provides a paracrine stimulus for trophoblast migration. BioMed Central Dev Biol 2,5–12. [CrossRef][Medline]
Laukaitis CM, Webb DJ, Donais K and Horwitz AF (2001) Differential dynamics of 5 integrin, paxillin, and -actinin during formation and disassembly of adhesions in migrating cells. J Cell Biol 153,1427–1440.
Lawson MA and Maxfield FR (1995) Ca++- and calcineurin-dependent recycling of an integrin to the front of migrating neutrophils. Nature 377,75–79. [CrossRef][Medline]
Leventhal PS, Shelden EA, Kim B and Feldman EL (1997) Tyrosine phosphorylation of paxillin and focal adhesion kinase during IGF-I stimulated lamellipodial advance. J Biol Chem 272,5214–5218.
Lishko VK, Yakubenko VP and Ugarova TP (2003) The interplay beween integrin alphaM beta2 and alpha5 beta1 during cell migration to fibronectin. Exp Cell Res 283,116–126.[CrossRef][Web of Science][Medline]
Ly DP, Zazzali KM and Corbett SA (2003) De novo expression of the integrin alpha5 beta1 regulates alphav beta3-mediated adhesion and migration on fibronectin. J Biol Chem 278,21878–21885.
Madri JA, Pratt BM and Yannariello-Brown J (1988) Matrix-driven cell size change modulates aortic endothelial cell proliferation and sheet migration. Am J Pathol 132,18–27.[Abstract]
Mostafavi-Pour Z, Asjari JA, Parkinson SJ, Parker PJ, Ng TTC and Humphies MJ (2003) Integrin-specific signaling pathways controlling focal adhesion formation and cell migration. J Cell Biol, 161, 155–167.
Palecek S, Huttenlocher A, Horwitz A and Lauffenburger D (1998) Physical and biochemical regulation of integrin release during rear detachment of migrating cells. J Cell Sci 111,929–940.[Abstract]
Pearse BMF and Robinson MS (1990) Clathin, adaptors, and sorting. Annu Rev Cell Biol 6,151–171.[CrossRef][Web of Science][Medline]
Pierini L, Lawson M, Eddy R, Hendet B and Maxfield F (2000) Oriented endocytic recycling of 5ß1 in motile neutrophils. Blood 95,2471–2480.
Ruoslahti E (1994) Fibronectin and its alpha 5 beta 1 integrin receptor in malignancy. Invas Metast 14,87–97.
Tani N, Higashiyama S, Kawaguchi N, Madarame J, Ota I, Ito Y, Ohoka Y, Shiosaka S, Takada Y and Matsuura N (2003) Expression level of integrin alpha 5 on tumor cells affects the rate of metastasis to the kidney. Br J Cancer 27,327–333.
Vicovac LJ, Jones CJP and Aplin JD (1995) Trophoblast differentiation during formation of anchoring villi in a model of the early human placenta in vitro. Placenta 16,41–56.[CrossRef][Web of Science][Medline]
Submitted on September 3, 2003; accepted on October 13, 2003.
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  M. Kabir-Salmani, M. N. Fukuda, M. Kanai-Azuma, N. Ahmed, S. Shiokawa, Y. Akimoto, K. Sakai, S. Nagamori, Y. Kanai, K. Sugihara, et al. The Membrane-Spanning Domain of CD98 Heavy Chain Promotes {alpha}v{beta}3 Integrin Signals in Human Extravillous Trophoblasts Mol. Endocrinol., March 1, 2008; 22(3): 707 - 715. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S.-K. Shields, C. Nicola, and C. Chakraborty Rho Guanosine 5'-Triphosphatases Differentially Regulate Insulin-Like Growth Factor I (IGF-I) Receptor-Dependent and -Independent Actions of IGF-II on Human Trophoblast Migration Endocrinology, October 1, 2007; 148(10): 4906 - 4917. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. Tartakover-Matalon, N. Cherepnin, M. Kuchuk, L. Drucker, I. Kenis, A. Fishman, M. Pomeranz, and M. Lishner Impaired migration of trophoblast cells caused by simvastatin is associated with decreased membrane IGF-I receptor, MMP2 activity and HSP27 expression Hum. Reprod., April 1, 2007; 22(4): 1161 - 1167. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. N. Sferruzzi-Perri, J. A. Owens, P. Standen, R. L. Taylor, G. K. Heinemann, J. S. Robinson, and C. T. Roberts Early treatment of the pregnant guinea pig with IGFs promotes placental transport and nutrient partitioning near term Am J Physiol Endocrinol Metab, March 1, 2007; 292(3): E668 - E676. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 V. Shukla, X. Coumoul, L. Cao, R.-H. Wang, C. Xiao, X. Xu, S. Ando, S. Yakar, D. LeRoith, and C. Deng Absence of the full-length breast cancer-associated gene-1 leads to increased expression of insulin-like growth factor signaling axis members. Cancer Res., July 15, 2006; 66(14): 7151 - 7157. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. Kabir-Salmani, S. Shiokawa, Y. Akimoto, K. Sakai, K. Sakai, and M. Iwashita Tissue Transglutaminase at Embryo-Maternal Interface J. Clin. Endocrinol. Metab., August 1, 2005; 90(8): 4694 - 4702. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 L. Lynch, P. I. Vodyanik, D. Boettiger, and M. A. Guvakova Insulin-like Growth Factor I Controls Adhesion Strength Mediated by {alpha}5{beta}1 Integrins in Motile Carcinoma Cells Mol. Biol. Cell, January 1, 2005; 16(1): 51 - 63. [Abstract] [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||