help button home button Endocrine Society Endocrinology
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow Request Copyright Permission
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Ryu, J. S.
Right arrow Articles by Guller, S.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Ryu, J. S.
Right arrow Articles by Guller, S.
Right arrowPubmed/NCBI databases
*Gene*GEO Profiles
*HomoloGene*UniGene
*Compound via MeSH
*Substance via MeSH
Hazardous Substances DB
*DEXAMETHASONE
Medline Plus Health Information
*Steroids
Endocrinology Vol. 140, No. 9 3904-3908
Copyright © 1999 by The Endocrine Society

ARTICLES

Steroid Regulation of Human Placental Integrins: Suppression of {alpha}2 Integrin Expression in Cytotrophoblasts by Glucocorticoids1

Jae S. Ryu, Robert J. Majeska, Yuehong Ma, Linda LaChapelle and Seth Guller

Departments of Obstetrics and Gynecology (J.S.R., Y.M., S.G.) and Biochemistry (S.G.), New York University School of Medicine, New York, New York 10016; and the Department of Orthopedics, Mount Sinai Medical Center (R.J.M.), New York, New York 10029

Address all correspondence and requests for reprints to: Dr. Seth Guller, Department of Obstetrics and Gynecology, New York University School of Medicine, 550 First Avenue, Tisch Hospital Room 531, New York, New York 10016.


   Abstract
Top
 Abstract
Introduction
 Materials and Methods
 Results
 Discussion
 References
 
Maintenance of uterine-placental attachment during human pregnancy may depend at least partly on adhesive interactions between cytotrophoblasts and their extracellular matrix (ECM). Such interactions are often mediated by integrins, signal-transducing heterodimeric transmembrane glycoproteins. We previously showed that glucocorticoid (GC) suppressed the expression of collagen and laminin in human placenta; here we show that GC also modulates the expression by human cytotrophoblasts of the integrin subunits {alpha}2 and ß1, components of a known receptor for these ECM ligands. Cytotrophoblasts were isolated from human term placentas, cultured up to 4 days in the presence of 0–1000 nM dexamethasone (DEX), and assayed for 1) integrin messenger RNA (mRNA) levels by Northern hybridization, 2) integrin subunit synthesis after [35S]methionine labeling, or 3) cell surface integrin levels after 125I labeling by lactoperoxidase. In four independent experiments, 100 nM DEX reduced mRNA levels for integrin {alpha}2 to 6 ± 1% of the control value. This effect was similar between 1–4 days of treatment and was dose dependent between 1–1000 nM DEX. Cortisol treatment (100 nM) inhibited levels of integrin {alpha}2 mRNA, but 100 nM testosterone, estradiol, and progesterone were less effective, suggesting that this response was specific to GC. In immunoprecipitation studies, treatment of cytotrophoblasts with 100 nM DEX for 2 days reduced the rates of synthesis of the {alpha}2 integrin subunit as well as its expression on the cell surface to 1–10% of control levels. DEX effects on the ß1 integrin subunit were less dramatic. DEX reduced ß1 mRNA levels to only 69 ± 8% of control levels, a smaller reduction compared with effects on {alpha}2 integrin mRNA. DEX inhibited ß1 protein synthesis and cell surface expression to 60–70% of control levels. In all experiments, DEX had no effect on total protein synthesis. Thus, our results demonstrate that GC treatment specifically and markedly down-regulates expression of {alpha}2 integrin subunit by human cytotrophoblasts. This finding is consistent with the concept that uterine-placental adherence across gestation may be regulated by coordinate effects on ECM ligands and cellular adhesion receptors.


   Introduction
Top
 Abstract
 Introduction
Materials and Methods
 Results
 Discussion
 References
 
EXTRACELLULAR matrix (ECM) proteins and their integrin receptors are known to regulate cell adhesion and migration in several cell types (1). ECM proteins and integrins have been suggested to play a specific role in placentation and maintenance of uterine-placental adhesion throughout human pregnancy (2). The establishment of uteroplacental circulation during pregnancy depends on the ability of multipotent placental cells, known as cytotrophoblasts, to regulate their expression and turnover of integrins and adhesion molecules during invasion and differentiation (3, 4). Conversely, pathological pregnancy was associated with aberrant patterns of expression of cytotrophoblast integrins (5, 6). Information is not currently available concerning the hormonal regulation of integrin expression in human placenta. Our group and others have extensively studied hormonal regulation of ECM protein expression in the human placenta (7, 8, 9, 10). For these studies, investigators have used primary cultures of cytotrophoblasts that can be isolated from term and first trimester placentas with high yield and excellent purity (11, 12). These cells undergo a process of syncytialization (i.e. formation of a multinucleate structure) in vitro that closely mimics differentiation in vivo (11). Studies using cytotrophoblasts have focused on modulation of oncofetal fibronectin (FN), a uniquely glycosylated form of FN that is present at uterine-placental and decidual-fetal membrane interfaces (13, 14). Expression of oncofetal FN in cytotrophoblasts was negatively regulated by glucocorticoid (GC) and cAMP (7, 13) and was positively regulated by transforming growth factor-ß (9, 10). Results from our laboratory indicated that dexamethasone (DEX), a synthetic GC, also suppressed the synthesis of laminin in cytotrophoblasts (7, 15), indicating that GC may coordinately reduce ECM protein expression in placenta. As human pregnancy is associated with elevated levels of GC in maternal and fetal sera (16, 17), we suggested that GC might chronically regulate placental ECM protein expression across gestation and acutely facilitate changes in ECM protein levels in association with labor, when levels of GC surge (17). In light of these results and the lack of information concerning hormonal regulation of placental integrin expression, in the present study we investigated the effects of steroids on integrin levels in cytotrophoblasts isolated from human placentas.

We report the novel finding that expression of {alpha}2 integrin in cytotrophoblasts is markedly suppressed by DEX treatment, suggesting that GC may profoundly regulate cytotrophoblast adherence across gestation. Elucidation of the effects of GC on adhesion protein expression at maternal-fetal interfaces is extremely important in light of the current recommendation for the antenatal use of GC for the enhancement of fetal lung maturity.


   Materials and Methods
Top
 Abstract
 Introduction
 Materials and Methods
Results
 Discussion
 References
 
Materials
Tissue culture medium, DEX, and lactoperoxidase were obtained from Sigma Chemical Co. (St. Louis, MO). Bovine sera were obtained from Gemini Bio-Products (Calabasas, CA). Laboratory plasticware was obtained from Falcon (Becton Dickinson and Co., Lincoln Park, NJ). ITS+, a mixture containing insulin, transferrin, and selenium, was purchased from Collaborative Research-Becton Dickinson and Co. (Bedford, MA). Ultraspec used for RNA isolation was purchased from Biotex Laboratories, Inc. (Houston, TX). [32P]Deoxy-CTP, [35S]protein labeling mix, and Na125I were purchased from New England Nuclear (Boston, MA). Plasmids containing complementary DNAs to human {alpha}2 and ß1 integrin subunits and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) were obtained from American Type Culture Collection (Manassas, VA). Zeta-Probe nylon membranes were obtained from Bio-Rad Laboratories, Inc. (Richmond, CA). Murine antihuman monoclonal antibodies to {alpha}2 and ß1 integrin subunits used in 35S labeling studies were obtained from Chemicon (Temecula, CA). The rabbit antihuman ß1 antibody used in surface labeling experiments was a gift from Filippo Giancotti (18, 19). All other reagents used in Northern blotting and immunoprecipitation experiments were purchased from previously described sources (7).

Cell culture
Placentas were obtained from uncomplicated pregnancies delivered at term by cesarean section. The institutional review board committee at New York University School of Medicine approved the study protocol. Placentas (n = 16) were transported to the laboratory immediately after delivery and were trimmed free of decidua and connective tissue. Cytotrophoblasts were isolated by procedures developed in our laboratory (7) based on established protocols (11, 12). Cytotrophoblasts were isolated from villous tissue using trypsin digestion and centrifugation on a continuous Percoll gradient (7). Using these procedures we reported cytotrophoblast purity of 95% or more (7). For experiments, cells were maintained in a 1:1 mixture containing phenol red-free Ham’s F-12/DMEM supplemented with 10% charcoal-stripped calf serum and ITS+ (a supplement used to obtain a final concentration of 6.25 µg/ml insulin, 6.25 µg/ml transferrin, 6.25 ng/ml selenous acid, 1.25 mg/ml BSA, and 5.35 µg/ml linoleic acid), i.e. SCS medium (7, 10).

Northern blotting
Total RNA was extracted from cytotrophoblasts using the Ultraspec procedure, a modification of the method of Chomczynski and Sacchi (20). Twenty-five to 50 µg total RNA were separated on a 1% agarose gel containing 2.2 M formaldehyde (21). After transfer of RNA to Zeta-Probe nylon membranes, levels of {alpha}2 and ß1 integrin subunit and GAPDH messenger RNAs (mRNAs) were detected using 32P-labeled complementary DNA probes as described previously (7). We previously used GAPDH to normalize Northern blot results in DEX-treated and control cytotrophoblasts, as the level of GAPDH mRNA is not regulated by DEX in cytotrophoblasts (22). Similarly, in the current study in five independent experiments in five different placentas, the level of GAPDH mRNA in cytotrophoblasts maintained for 2 days in 100 nM DEX was 103 ± 10% of control values.

Immunoprecipitation
Rates of integrin synthesis were determined in cytotrophoblasts maintained on 10-cm dishes (~107 cells/experimental point) for 48 h in SCS medium with and without 100 nM DEX. Cells were then labeled for 3 h in methionine-free SCS medium containing 75 µCi/ml [35S]protein labeling mix as we have previously described (7, 15). Cells were washed twice with PBS and were incubated on ice for 15 min in a mixture containing PBS, 1 mM MgCl2, 0.5 mM CaCl2, 0.5% Nonidet P-40, and a protease inhibitor cocktail consisting of 10 µg/ml each of leupeptin, aprotonin, pepstatin, soybean trypsin inhibitor, and phenylmethylsulfonylfluoride. Cells were then scraped, and levels of trichloroacetic acid (TCA)-precipitable radioactivity were determined (7). Approximately 107 TCA-precipitable counts per min of precleared labeled cell extracts were incubated with a 1:50 dilution of antiintegrin antibody and protein G-Sepharose as previously described (7). Immunoprecipitation gels were dried on a gel dryer and exposed to film at -80 C for 1–4 days. Immune complexes were washed, and electrophoresis was carried out on 6–7% polyacrylamide gels under reducing conditions as previously described (7).

For surface labeling studies, cells maintained in culture as described above were washed in HBSS without Ca2+ and Mg2+ and were removed from the substratum by treatment with 0.25% trypsin. The cells were then washed twice in PBS and resuspended in 0.3 ml PBS. Lactoperoxidase (200 µl of a 1 mg/ml stock), Na125I (15 µl of a 100 mCi/ml stock), and hydrogen peroxide (10 µl of a 0.1% stock) were then sequentially added, and the mixture was incubated for 5 min at room temperature. Ten microliters of 0.1% hydrogen peroxide were added, and the mixture was incubated for an additional 3 min at room temperature. The cells were then centrifuged (1000 x g, 5 min), washed four times with DMEM containing 0.02% sodium azide, and lysed in buffer containing 0.5% Triton X-100, 5 mM EDTA, 1 mM CaCl2, 1 mM MgCl2, and 150 mM NaCl-Tris, pH 7.4, supplemented with a protease inhibitor cocktail (7). TCA-precipitable counts per min were determined (7), and immunoprecipitation and electrophoresis were carried out as described above, except that rabbit antihuman integrin polyclonal sera and protein A-Sepharose were employed to recover labeled integrins.

Data analysis
Quantitation of autoradiographic signals was performed using the Electrophoresis Documentation and Analysis System 120 and Digital Science 1D Image Software (Eastman Kodak Co., Rochester, NY). The level of integrin expression in DEX-treated cells is expressed as the mean percentage of the control value ± SE. Multiple measurement one-way ANOVA was carried out using SigmaStat software (Jandel Scientific Corp., San Rafael, CA). P < 0.05 was considered significant. The Pearson correlation was used to determine r and P values for the DEX dose-response experiments.


   Results
Top
 Abstract
 Introduction
 Materials and Methods
 Results
Discussion
 References
 
GC treatment markedly suppresses {alpha}2 integrin mRNA in cytotrophoblasts
Cytotrophoblasts isolated from human term placentas were incubated for 1–4 days in SCS medium without or with 100 nM DEX, and expression of {alpha}2 and ß1 integrin mRNA was measured by Northern blotting and normalized to levels of GAPDH mRNA. We observed that DEX treatment reduced the level of {alpha}2 integrin mRNA, detected at a mol wt of approximately 7 kb, to 5–10% of the control levels on all days studied (Fig. 1Go). DEX treatment reduced the level of ß1 integrin mRNA, detected at a mol wt of 3.2 kb, to 60–70% of the control levels. In four independent experiments, a 2-day treatment of cytotrophoblasts with 100 nM DEX significantly reduced the level of {alpha}2 integrin mRNA to 6 ± 1% of control levels (Table 1Go), whereas the level of ß1 integrin mRNA was 69 ± 8% of control levels. Statistical analysis also revealed that DEX treatment caused a greater reduction of {alpha}2 integrin mRNA than of ß1 integrin mRNA (Table 1Go).



View larger version (76K):
[in this window]
[in a new window]
  		Figure 1. Time course of DEX effects on integrin mRNA expression in term cytotrophoblasts. Cytotrophoblasts were maintained for up to 96 h in culture medium without (C) and with (D) 100 nM DEX, and levels of {alpha}2 and ß1 integrin subunit mRNAs were assessed after Northern blotting and hybridization of 32P-labeled probes. This experiment represents three time courses performed with cells isolated from three separate placentas.

 

View this table:
[in this window]
[in a new window]
  		Table 1. DEX-mediated inhibition of integrin expression in cytotrophoblasts isolated from human term placentas

 
We observed that DEX treatment suppressed expression of {alpha}2 integrin mRNA between 0.1–1000 nM (Fig. 2Go). Treatment of cytotrophoblasts with 100 nM DEX cortisol significantly reduced levels of {alpha}2 integrin mRNA compared with control values (Table 2Go). Conversely, the presence of 100 nM progesterone, estradiol, or testosterone did not markedly affect levels of {alpha}2 integrin mRNA compared with control values (Table 2Go). A similar pattern of GC-specific down-regulation of {alpha}2 integrin mRNA was noted at a steroid concentration of 1000 nM (not shown). Medroxyprogesterone acetate (a synthetic progestin) treatment significantly reduced levels of {alpha}2 integrin mRNA (Table 2Go). This result is consistent with the reported GC-like activity of this steroid (23). These results indicated that {alpha}2 integrin levels in cytotrophoblasts were regulated specifically by GC.



View larger version (47K):
[in this window]
[in a new window]
  		Figure 2. Dose-dependence of DEX-mediated reduction of {alpha}2 integrin mRNA expression in cytotrophoblasts. Cells were maintained for 48 h in control medium (C) or in medium supplemented with the indicated nanomolar concentration of DEX. Levels of {alpha}2 integrin subunit and GAPDH mRNAs were determined after Northern blotting and hybridization with labeled probes. This representative experiment was carried out three times in cells isolated from three separate placentas. For cumulative dose-response results, statistical analysis yielded r and P values of 0.92 and 0.03, respectively.

 

View this table:
[in this window]
[in a new window]
  		Table 2. Steroid hormone effects on {alpha}2 integrin mRNA expression in cytotrophoblasts isolated from human term placentas

 
DEX treatment inhibits expression of {alpha}2 integrin protein in cytotrophoblasts
Integrin protein synthesis was examined in immunoprecipitation studies in cytotrophoblasts maintained in culture medium for 48 h with and without 100 nM DEX. Using either anti-{alpha}2 integrin (Fig. 3AGo) or anti-ß1 integin (Fig. 3BGo) antibody for immunoprecipitation, we observed that DEX treatment down-regulated the expression of a 165-kDa species to 5% of control levels (denoted by the large arrow in each of the panels). This molecular mass is consistent with that previously described for the {alpha}2 integrin subunit (24). The ß1-specific antibody would also be expected to immunoprecipitate the {alpha}2 integrin subunit, as the {alpha}2-subunit can be complexed to ß1 in the form of an {alpha}2ß1 integrin (1). The levels of a protein migrating with a molecular mass of approximately 125–130 kDa (denoted by the lower small arrow in Fig. 3BGo), consistent with that reported for the ß1-subunit (24), was down-regulated to approximately 60% of control levels. A second ß1-associated protein with a molecular mass of approximately 180 kDa (denoted by the upper small arrow in Fig. 3BGo), consistent with that reported for the {alpha}1-subunit (24), was not affected by DEX treatment. The 165-, 125-, and 180-kDa species were not observed when immunoprecipitations were carried out with either anti-{alpha}v integrin or anti-ß3 integrin subunit antibodies (not shown). A nonspecific band at approximately 65 kDa was noted in all immunoprecipitations.



View larger version (47K):
[in this window]
[in a new window]
  		Figure 3. Effect of DEX treatment on integrin synthesis in term cytotrophoblasts. Duplicate dishes of cytotrophoblasts were maintained for 48 h in culture medium in the absence (C) or presence (D) of 100 nM DEX. Cells were then metabolically labeled with [35S]methionine, labeled integrins were immunoprecipitated with either anti-{alpha}2 (A) or anti-ß1 (B) antibody, and SDS-PAGE was carried out. The large arrow in each of the panels denotes the position of the 165-kDa species corresponding to the {alpha}2 integrin subunit. The lower small arrow in B indicates the position of the 125- to 130-kDa species corresponding to the ß1-subunit. The upper small arrow at 180-kDa in B denotes the position of the {alpha}1-subunit. The migration of molecular mass standards is indicated at the right of the prints. This representative experiment was performed three times in cells isolated from three separate placentas.

 
To determine the effect of GC on the expression of integins on the cell surface, cells were maintained with and without 100 nM DEX for 48 h. Cells were then trypsinized, and cell surface proteins were labeled with Na125I. After immunoprecipitation of labeled integrins with anti-ß1 integrin antibody, we observed that DEX treatment reduced cell surface levels of {alpha}2 and ß1 integrin subunits to approximately 10% and 70% of control values, respectively (Fig. 4Go).



View larger version (56K):
[in this window]
[in a new window]
  		Figure 4. GC effects on cell surface expression of integrins in cytotrophoblasts. Cells were incubated for 48 h without (C) and with (D) 100 nM DEX, and after trypsinization, cell surface proteins were labeled with Na125I. Cell surface integrins were then immunoprecipitated with anti-ß1 integrin subunit antibody and were separated by SDS-PAGE. This representative experiment was performed twice in cells isolated from two separate placentas.

 
We noted that treatment of cytotrophoblasts with 100 nM DEX did not significantly affect the rate of protein synthesis or the level of total cell protein (not shown). These results support our earlier findings (7, 22) and demonstrate that the GC-dependent reduction in integrin expression in cytotrophoblasts was not indicative of a nonspecific reduction in cellular protein.

Thus, our results demonstrated that GC treatment specifically and markedly down-regulated expression of {alpha}2 integrin mRNA and protein in cytotrophoblasts isolated from human term placentas.


   Discussion
Top
 Abstract
 Introduction
 Materials and Methods
 Results
 Discussion
References
 
The {alpha}2ß1 integrin is a major receptor for collagen and laminin as well as a cell-cell adhesion molecule (25, 26, 27). The {alpha}2-subunit is expressed in epithelium of intestinal crypts, mammary ducts, and the basal layer of keratinizing cells, where it is postulated to regulate cell proliferation (28). Increased expression of the {alpha}2ß1 integrin is associated with reorganization of connective tissue in fibroblasts and increased production of interstitial collagenase and collagen in osteogenic cell lines (29, 30). Expression of this integrin correlated with metastatic potential of melanoma and breast carcinoma cell lines (29, 31).

Implantation and placental development requires that cytotrophoblasts transiently acquire an invasive phenotype that is accompanied by appropriate changes in expression of cell surface integrins and extracellular matrix proteins (2, 3, 4). In the first trimester of human pregnancy, cytotrophoblast stem cells differentiate into a syncytium or form columns of nonpolarized cells and establish a connection between the developing embryo and the uterus (2, 3, 4). Cytotrophoblasts within the column acquire an invasive phenotype and invade the uterine spiral arteries, the decidua, and the first third of the myometrium (3, 4). This process is accompanied by the loss of {alpha}6ß4 integrin and induction of {alpha}5ß1 and {alpha}1ß1 integrins in cytotrophoblasts (3, 4). Failure of cytotrophoblasts in the placental bed to express vascular cell adhesion molecules is associated with the absence of endovascular invasion of uterine vessels in preeclampsia (6).

In the current study, we report that GC treatment markedly down-regulated expression of the {alpha}2 integrin subunit in cytotrophoblasts isolated from human term placentas. Time-course studies revealed that cytotrophoblasts expressed the {alpha}2-subunit at high levels immediately after plating, whereas its levels decreased significantly between 24 and 96 h of culture. During this period in culture, mononuclear cytotrophoblasts undergo a dramatic differentiation process in forming a multinuclear syncytium (11). Syncytialization of cytotrophoblasts in vitro is known to be accompanied by a loss of invasive patterns of expression (e.g. high levels of protease activity) (32) and acquisition of the characteristics of a mature syncytium (e.g. high levels of expression of hCG) (7, 11). Therefore, our data suggest that syncytialization is accompanied by down-regulation of {alpha}2 integrin subunit expression.

Surface labeling and immunoprecipitation results indicated that the {alpha}2ß1 integrin was a major ß1 integrin synthesized by cytotrophoblasts in vitro. We did not anticipate this finding, as previous immunohistochemical analyses detected staining for {alpha}1, {alpha}3, {alpha}5, and ß1, but not {alpha}2, integrin subunits in sections of first trimester and term human placentas (3, 33, 34). The {alpha}2 subunit is expressed at high levels in cytotrophoblasts and syncytiotrophoblasts of hydatidiform mole (35). It is of note that {alpha}2 integrins are detected in first trimester trophoblasts by immunofluorescent labeling after isolation by trypsin digestion and Percoll gradient centrifugation (35), indicating that trypsinization may reveal cryptic sites in {alpha}2ß1 integrin. It is possible that human cytotrophoblasts transiently express the {alpha}2ß1 integrin during invasion and implantation as is the case for the {alpha}vß3 integrin in melanoma cells during vascular invasion (36). In the present study, results from Northern blotting, immunoprecipitation, and surface labeling experiments indicated that GC effects on {alpha}2 integrin subunit expression were greater than those noted for ß1 subunit. This finding is similar to other studies showing differential regulation of individual {alpha}- and ß-subunits by fibroblast growth factor-2 and retinoic acid in endothelial cells and osteoclasts (37, 38), respectively. This suggests that GC may reduce the expression of individual ß1 integrins in cytotrophoblasts (i.e. the {alpha}2ß1 integrin) without coordinately suppressing the synthesis of all ß1 integrins in human placenta. Growth factors, but not steroids, modulated integrin expression in uterine stromal cells isolated from human endometrium (39), suggesting that integrin expression is differentially regulated in fetal and maternal compartments of the uterine-placental interface.

In conclusion, our results suggest that GC markedly suppresses {alpha}2 integrin expression in cytotrophoblasts isolated from human term placentas. As GC levels in maternal serum rise during pregnancy and peak during labor (16, 17), this suggests that GC-mediated regulation of integrin expression may play an important role in placental development and regulation of trophoblast adherence across gestation.


   Acknowledgments
 
We thank Dr. En-Yu Wang for her technical assistance with preparation of cytotrophoblasts, Dr. Ray Sanders for help with the surface labeling studies, and Dr. Donato D’Antona for assistance with statistical analyses.


   Footnotes
 
1 This work was supported in part by NIH Grant HD-33909 (to S.G.). Back

Received December 28, 1998.


   References
Top
 Abstract
 Introduction
 Materials and Methods
 Results
 Discussion
 References
 

  1. Howe A, Aplin AE, Alahari SK, Juliano RL 1998 Integrin signaling and cell growth control. Curr Opin Cell Biol 10:220–231[CrossRef][Medline]
  2. Cross JC, Werb Z, Fisher SJ 1994 Implantation and the placenta: key pieces of the development puzzle. Science 266:1508–1516[Abstract/Free Full Text]
  3. Damsky CH, Fitzgerald ML, Fisher SJ 1992 Distribution patterns 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
  4. Fisher SJ, Cui T-Y, Zhang, L, Hartman L, Grahl K, Guo-Yang Z, Tarpey J, Damsky CH 1989 Adhesive and degradative properties of human placental cytotrophoblast cells in vitro. J Cell Biol 109:891–902[Abstract/Free Full Text]
  5. Zhou Y, Damsky CH, Chiu K, Roberts JM, Fisher SJ 1993 Preeclampsia is associated with abnormal expression of adhesion molecules by invasive cytotrophoblasts. J Clin Invest 91:950–960
  6. Zhou Y, Damsky CH, Fisher SJ 1997 Preeclampsia is associated with failure of human cytotrophoblasts to mimic a vascular adhesion phenotype. One cause of defective endovascular invasion in this syndrome? J Clin Invest 99:2152–2164[Medline]
  7. Guller S, Wozniak R, Krikun G, Burnham JM, Kaplan P, Lockwood CJ 1993 Glucocorticoid suppression of human placental fibronectin expression: implications in uterine-placental adherence. Endocrinology 133:1139–1146[Abstract/Free Full Text]
  8. Ringler GE, Kallen CB, Strauss III JF 1989 Regulation of human trophoblast function by glucocorticoids: dexamethasone promotes increased secretion of chorionic gonadotropin. Endocrinology 124:1625–1631[Abstract/Free Full Text]
  9. Feinberg RF, Kliman HJ, Wang C-L 1994 Transforming growth factor-ß stimulates trophoblast oncofetal fibronectin synthesis in vitro: implications for trophoblast implantation in vivo. J Clin Endocrinol Metab 78:1241–1248[Abstract]
  10. Guller S, Wozniak R, Kong L, Lockwood CJ 1995 Opposing actions of transforming growth factor-ß and glucocorticoids in the regulation of fibronectin expression in the human placenta. J Clin Endocrinol Metab 80:3273–3278[Abstract]
  11. Kliman HJ, Nestler JE, Sermasi E, Sanger JM, Strauss III JF 1986 Purification, characterization, and in vitro differentiation of cytotrophoblasts from human term placentae. Endocrinology 118:1567–1582[Abstract/Free Full Text]
  12. Douglas GC, King BF 1989 Isolation of pure villous cytotrophoblast from human term placenta using immunomagnetic microspheres. J Immunol Methods 119:259–268[CrossRef][Medline]
  13. Feinberg RF, Kliman HJ, Lockwood CJ 1991 Is oncofetal fibronectin a trophoblast glue for implantation? Am J Pathol 138:537–543[Abstract]
  14. Lockwood CJ, Senyei AE, Dische MR, Casal D, Shah KD, Thung SN, Jones L, Deligdisch L, Garite TJ 1991 Fetal fibronectin in cervical and vaginal secretions as a predictor of preterm delivery. N Engl J Med 325:669–674[Abstract]
  15. Guller S, Markiewicz L, Wozniak R, Burnham JM, Wang EY, Kaplan P, Lockwood CJ 1994 Developmental regulation of glucocorticoid-mediated effects on extracellular matrix protein expression in the human placenta. Endocrinology 134:2064–2071[Abstract]
  16. Dormer RA, France JT 1973 Cortisol and cortisone levels in umbilical cord plasma and maternal plasma of normal pregnancies. Steroids 21:497–510[CrossRef][Medline]
  17. Dorr HG, Heller A, Versmold HT, Sippell WG, Herrmann M, Bidlingmaier F, Knorr D 1989 Longitudinal study of progestins, mineralocorticoids, and glucocorticoids throughout human pregnancy. J Clin Endocrinol Metab 68:863–868[Abstract/Free Full Text]
  18. Giancotti FG, Ruoslahti E 1990 Elevated levels of the {alpha}5ß1 fibronectin receptor suppress the transformed phenotype of Chinese hamster ovary cells. Cell 60:849–859[CrossRef][Medline]
  19. Defilippi P, Silengo L, Tarone G 1992 {alpha}6ß1 integrin (laminin receptor) is down-regulated by tumor necrosis factor-{alpha} and interleukin-1ß in human endothelial cells. J Biol Chem 267:18303–18307[Abstract/Free Full Text]
  20. Chomczynski P, Sacchi N 1987 Single-step method of RNA isolation by acid guanidinium-thiocyanate-phenol-chloroform extraction. Anal Biochem 156–159
  21. Sambrook J, Fritsch EF, Maniatis T 1989 Molecular Cloning: A Laboratory Manual, ed 2. Cold Spring Harbor Laboratory, Cold Spring Harbor, pp 7.37–7.45
  22. Yoon DY, Ma Y, Krikun G, Lockwood CJ, LaChapelle L, Guller S 1998 Glucocorticoid effects in the human placenta: evidence that dexamethasone-mediated inhibition of fibronectin expression in cytotrophoblasts involves a protein intermediate. J Clin Endocrinol Metab 83:632–637[Abstract/Free Full Text]
  23. Guller S, LaCroix NC, Krikun G, Wozniak R, Markiewicz L, Wang E-Y, Kaplan P, Lockwood CJ 1993 Steroid regulation of oncofetal fibronectin expression in human cytotrophoblasts. J Steroid Biochem Mol Biol 46:1–10[CrossRef][Medline]
  24. Hemler ME 1990 VLA proteins in the integrin family: structures, functions, and their role on leukocytes. Annu Rev Immunol 8:365–400[CrossRef][Medline]
  25. Berdichevsky F, Alford D, D’Souza, B, Taylor-Papadimitriou J 1994 Branching morphogenesis of human mammary epithelial cells in collagen gels. J Cell Sci 107:3557–3568[Abstract]
  26. Marchisio PC, Bondanza S, Cremona O, Cancedda R, De Luca M 1991 Polarized expression of integrin receptors ({alpha}6ß4, {alpha}2ß1, {alpha}3ß1, and {alpha}vß5) and their relationship with the cytoskeleton and basement membrane matrix in cultured human keratinocytes. J Cell Biol 112:761–773[Abstract/Free Full Text]
  27. Elices MJ, Hemmler ME 1989 The human integrin VLA-2 is a collagen receptor on some cells and a collagen/laminin receptor on others. Proc Natl Acad Sci USA 86:9906–9910[Abstract/Free Full Text]
  28. Zutter MM, Santoro SA 1990 Widespread histologic distribution of the {alpha}2ß1 integrin cell-surface collagen receptor. Am J Pathol 137:113–120[Abstract]
  29. Klein E, Dressel D, Steinmayer T, Mauch C, Eckes B, Krieg T, Bankert RB, Weber L 1991 Integrin {alpha}2ß1 is upregulated in fibroblasts and highly aggressive melanoma cells in three-dimensional collagen lattices and mediates the reorganization of collagen fibrils. J Cell Biol 115:1427–1436[Abstract/Free Full Text]
  30. Riikonen T, Westermarck J, Koivisto L, Broberg A, Kahari V-M, Heino J 1995 Integrin {alpha}2ß1 is a positive regulator of collagenase (MMP-1) and collagen {alpha}1(I) gene expression. J Biol Chem 270:13548–13552[Abstract/Free Full Text]
  31. Keely PJ, Fong AM, Zutter MM, Santoro SA 1995 Alteration of collagen-dependent adhesion, motility, and morphogenesis by the expression of antisense {alpha}2 integrin mRNA in mammary cells. J Cell Sci 108:595–607[Abstract]
  32. Queenan Jr JT, Kao LC, Arboleda CE, Ulloa-Aguirre A, Golos TG, Cines DB, Strauss III JF 1987 Regulation of urokinase-type plasminogen activator production by cultured human cytotrophoblasts. J Biol Chem 262:10903–10906[Abstract/Free Full Text]
  33. Aplin JD 1993 Expression of integrin a6ß4 in human trophoblast and its loss from extravillous cells. Placenta 14:203–215[CrossRef][Medline]
  34. Korhonen M, Ylanne J, Laitinen L, Cooper HM, Quaranta V, Virtanen I 1991 Distribution of the {alpha}1-{alpha}6 integrin subunits in human developing term placenta. Lab Invest 65:347–356[Medline]
  35. Bischof P, Redard M, Gindre P, Vassilakos P, Campana A 1993 Localization of {alpha}2, {alpha}5, and {alpha}6 integrin subunits in human endometrium, decidua and trophoblast. Eur J Obstet Gynecol 51:217–226[CrossRef][Medline]
  36. Montgomery A, Reisfield R, Cheresh D 1994 Integrin {alpha}vß3 rescues melanoma cells from apoptosis in three-dimensional dermal collagen. Proc Natl Acad Sci USA 91:8856–8860[Abstract/Free Full Text]
  37. Klein S, Giancotti FG, Presta M, Albelda SM, Buck CA, Rifkin DB 1993 Basic fibroblast growth factor modulates integrin expression in microvascular endothelial cells. Mol Biol Cell 4:973–982[Abstract]
  38. Chiba M, Teitelbaum SL, Cao X, Ross FP 1996 Retinoic acid stimulates expression of the functional osteoclast integrin {alpha}vß3: transcriptional activation of the ß3 but not the {alpha}v gene. J Cell Biochem 62:467–475[CrossRef][Medline]
  39. Grosskinsky CM, Yowell CW, Sun J, Parise LV, Lessey BA 1996 Modulation of integrin expression in endometrial stromal cells in vitro. J Clin Endocrinol Metab 81:2047–2054[Abstract]



This article has been cited by other articles:


Home page
 Hum Reprod UpdateHome page
A. E. Michael and A. T. Papageorghiou
Potential significance of physiological and pharmacological glucocorticoids in early pregnancy
Hum. Reprod. Update, September 1, 2008; 14(5): 497 - 517.
[Abstract] [Full Text] [PDF]

Home page
 EndocrinologyHome page
M.-J. Lee, Z. Wang, H. Yee, Y. Ma, N. Swenson, L. Yang, S. S. Kadner, R. N. Baergen, S. K. Logan, M. J. Garabedian, et al.
Expression and Regulation of Glucocorticoid Receptor in Human Placental Villous Fibroblasts
Endocrinology, November 1, 2005; 146(11): 4619 - 4626.
[Abstract] [Full Text] [PDF]

Home page
 J. Clin. Endocrinol. Metab.Home page
E. Chamoux, L. Bolduc, J.-G. Lehoux, and N. Gallo-Payet
Identification of Extracellular Matrix Components and Their Integrin Receptors in the Human Fetal Adrenal Gland
J. Clin. Endocrinol. Metab., May 1, 2001; 86(5): 2090 - 2098.
[Abstract] [Full Text]

This Article
Right arrow Abstract Freely available
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow Request Copyright Permission
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Ryu, J. S.
Right arrow Articles by Guller, S.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Ryu, J. S.
Right arrow Articles by Guller, S.
Right arrowPubmed/NCBI databases
*Gene*GEO Profiles
*HomoloGene*UniGene
*Compound via MeSH
*Substance via MeSH
Hazardous Substances DB
*DEXAMETHASONE
Medline Plus Health Information
*Steroids

HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Endocrinology Endocrine Reviews J. Clin. End. & Metab.
Molecular Endocrinology Recent Prog. Horm. Res. All Endocrine Journals