ABSTRACT
Recent attention has focused on the expression of integrin molecules within the endometrium, and their relation to infertility. The present prospective study was undertaken to determine whether the endometrium of women with unexplained infertility differs in the expression of very late activation antigens [VLA] from the endometrium of normal fertile women. Thirty samples of endometrial biopsies from hysterectomies with non-endometrial pathology and 28 endometrial samples by uterine curetting from infertile women in secretary phase at implantation time were collected, stained with three monoclonal antibodies against a1 integrin subunits including VLA-1 to VLA-3 by immunohistochemical technique and then assessed semi-quantitatively by microscope. Chi-Square test was used to compare the expression of VLA antigens on epithelial cells, stromal cells, lymphocytes and vessels within endometrial tissues between two groups. The results showed that most VLA integrins were present in fertile and infertile endometrium tissues. There were similarities and differences in the expression of VLA molecules in different compartments. VLA-2, VLA-3 expression on endometrial compartments showed an unaltered pattern of staining during the putative window of implantation in either fertile or infertile women with no significant differences [Pvalue> 0.5]. VLA-1 expression on endometrial compartments changed in fertile and unexplained infertile women, the differences were related to the presence or lack of the molecules on epithelial and stromal cells respectively. Differences may explain causes of unexplained infertility, and suggests that certain integrins may participate in the cascade of molecular events leading to successful implantation and early placental development which requires more investigations
Subject(s)
Humans , Female , Infertility, Female/etiology , Integrin alpha1beta1 , Integrin alpha2beta1 , Integrin alpha3beta1 , Uterus , HysterectomyABSTRACT
Betaig-h3 (betaig-h3) is a secretory protein composed of fasciclin I-like repeats containing sequences that allows binding of integrins and glycosaminoglycans in vivo. Expression of betaig-h3 is responsive to TGF-beta and the protein is found to be associated with extracellular matrix (ECM) molecules, implicating betaig-h3 as an ECM adhesive protein of developmental processes. We previously observed predominant expression of betaig-h3 expression in the basement membrane of proximal tubules of kidney. In this study, the physiological relevance of such localized expression of betaig-h3 was examined in the renal proximal tubular epithelial cells (RPTEC). RPTEC constitutively expressed betaig-h3 and the expression was dramatically induced by exogenous TGF-beta1 treatment. betaig-h3 and its second and fourth FAS1 domain were able to mediate RPTEC adhesion, spreading and migration. Two known alpha3beta1 integrin-interaction motifs including aspartatic acid and isoleucine residues, NKDIL and EPDIM in betaig-h3 were responsible to mediate RPTEC adhesion, spreading, and migration. By using specific antibodies against integrins, we confirmed that alpha3beta1 integrin mediates the adhesion and migration of RPTECs on betaig-h3. In addition, it also enhanced proliferation of RPTECs through NKDIL and EPDIM. These results indicate that betaig-h3 mediates adhesion, spreading, migration and proliferation of RPTECs through the interaction with alpha3beta1 integrin and is intimately involved in the maintenance and the regeneration of renal proximal tubular epithelium.
Subject(s)
Humans , Amino Acid Motifs , Antibodies, Blocking/immunology , Cell Adhesion/physiology , Cell Movement/physiology , Cell Proliferation , Cells, Cultured , Epithelial Cells/drug effects , Extracellular Matrix Proteins/chemistry , Integrin alpha3beta1/chemistry , Kidney Tubules, Proximal/cytology , Peptides/chemistry , Protein Interaction Mapping , Transforming Growth Factor beta/chemistryABSTRACT
Angiogenesis is a fundamental biological process including endothelial cell adhesion, migration, invasion and tube formation. Integrin receptors of endothelial cells play important roles in angiogenesis. They mediate cell-cell contact and cell adhesion to extracellular matrix. Roles of integrins have been described for a number of cell types. ECV304 endothelial cells were known to overexpress alpha3beta1 integrin and to form tube like structure in 3-D Matrigel culture. However the function of alpha3beta1 integrin in endothelial cells remains to be determined. Therefore, we have investigated morphological characteristics of ECV304 cells and roles of alpha3beta1 integrin in angiogenesis. To elucidate several characteristics, ECV304 endothelial cells were compared with HUVEC in the aspect of morphology, localization of integrins, angiogenesis pattern. In addition, role of alpha3beta1 integrin were analyzed in the aspect of endothelial cell binding, migration, invasion and tube formation on Matrigel. The result showed that alpha3beta1 integrin overexpressed ECV304 endothelial cells showed strong adhesiveness to extracellular matrix proteins, and high migration and invasion activities. Furthermore, expression of alpha3beta1 integrin was increased according to time course during in vitro culture and was continuously strong in ECV304 cells on 3-D Matrigel culture. These results indicate that alpha3beta1 integrin is able to be a critical component in control of angiogenesis by regulation of cell adhesion, migration, invasion and tube formation of ECV304 endothelial cells.