Enhanced integrin-mediated human osteoblastic adhesion to porous amorphous calcium phosphate/poly (L-lactic acid) composite / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>The initial osteoblastic adhesion to materials characterizes the first phase of cell-material interactions and influences all the events leading to the formation of new bone. In a previous work, we developed a novel amorphous calcium phosphate (ACP)/poly(L-lactic acid) (PLLA) material that demonstrated morphologic variations in its microstructure. The aim of this study was to investigate the initial interaction between this material and osteoblastic cells. Cellular attachment and the corresponding signal transduction pathways were investigated.</p><p><b>METHODS</b>A porous ACP/PLLA composite and PLLA scaffold (as a control) were incubated in fetal bovine serum (FBS) containing phosphate-buffered saline (PBS), and the protein adsorption was determined. Osteoblastic MG63 cells were seeded on the materials and cultured for 1, 4, 8, or 24 hours. Cell attachment was evaluated using the MTS method. Cell morphology was examined using scanning electron microscopy (SEM). The expression levels of the genes encoding integrin subunits α1, α5, αv, β1, focal adhesion kinase (FAK), and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) were determined using real-time reverse transcription polymerase chain reaction (RT-PCR).</p><p><b>RESULTS</b>The ACP/PLLA material significantly increased the protein adsorption by 6.4-fold at 1 hour and 2.4-fold at 24 hours, compared with the pure PLLA scaffold. The attachment of osteoblastic cells to the ACP/PLLA was significantly higher than that on the PLLA scaffold. The SEM observation revealed a polygonal spread shape of cells on the ACP/ PLLA, with the filopodia adhered to the scaffold surface. In contrast, the cells on the PLLA scaffold exhibited a spherical or polygonal morphology. Additionally, real-time RT-PCR showed that the genes encoding the integrin subunits α1, αv, β1, and FAK were expressed at higher levels on the ACP/PLLA composite.</p><p><b>CONCLUSIONS</b>The ACP/PLLA composite promoted protein adsorption and osteoblastic adhesion. The enhanced cell adhesion may be mediated by the binding of integrin subunits α1, αv, and β1, and subsequently may be regulated through the FAK signal transduction pathways.</p>

Effects of Magnesium Sulfate on the Apoptosis and Invasion of Cytotrophoblasts under Hypoxic Condition / 대한산부인과학회잡지

OBJECTIVE: To determine the effect of magnesium sulfate (MgSO4) on the apoptosis and invasion of cytotrophoblasts in vitro under normal and hypoxic condition as assessed immunoblot analyses of Bcl-2/Bax, invasion assay and immunohistochemical staining of integrin alpha1. METHODS: Normal cytotrophoblasts were isolated from second trimester placentas and cultured in several physiologically relevant concentrations of MgSO4 under control tissue culture condition (20% O2) or hypoxic condition (1-2% O2). Apoptosis of cytotrophoblasts was estimated by immunoblotting for Bcl-2/Bax, invasiveness was estimated by invasion assay and immunohistochemical staining of Integrin alpha1. RESULTS: The expression of Bcl-2 did not change under standard condition, but it decreased under hypoxic condition with increasing of MgSO4 concentrations. The expression of Bax did not change under both standard condition and hypoxic condition with increasing MgSO4 concentrations. The invasiveness of cytotrophoblasts significantly decreased under both control and hypoxic conditions with increasing of MgSO4 concentrations. The expression of Integrin alpha1 immumohistochemical staining significantly decreased under control condition and showed decreasing tendency under hypoxic condition with increasing of MgSO4 concentrations. CONCLUSION: MgSO4 might induce cytotrophoblasts to the apoptosis and inhibit invasion of cytotrophoblasts under hypoxic condition.

The Expression of Integrins in Korean Breast Cancer Patients

PURPOSE: Integrins are cell surface proteins that anchor the cells to the extra-cellular matrix. It has recently been found that integrins are involved in proliferations, migration, differentiation and survival signal transduction. We studied the expression of integrins in normal and cancer tissue of Korean breast cancer patients, and investigated the relationship between integrin expression and the characteristics of breast cancer. METHODS: Normal and malignant breast tissues were taken from 25 breast cancer patients who were admitted to the Ajou University Hospital. Specimens were immediately preserved in a nitrogen tank at the time of the operation. Total RNA was extracted, and semi-quantitative reverse transcriptase polymerase chain reactions (RT-PCR) performed with PCR primers for integrin alpha1, alpha2, alpha5, and alphav, and integrin beta1, and beta3. The integrin expressions were compared between the normal and malignant tissues, and the expressions were analyzed in relation to tumor characteristics. RESULTS: Integrin alpha1, alpha5, alphav, beta1, and beta3 were significantly over-expressed in breast cancer tissue than in normal tissue. There was no difference in integrin alpha2 expression between the normal and cancer tissues. Integrin beta1 was over-expressed to a greater extent in lower histological grade carcinomas and to a lesser extent in high grade tumors. Hormonal receptor positive tumor tissue had more alphav, alpha5, and beta1 integrin expressions. There was no significant relationship between integrins and tumor size, lymph node meta-stasis, lymphovascular involvement, or c-erb-B2 expression. CONCLUSIONS: Integrins alpha1, alpha5, alphav and beta3 were over- expressed in malignant breast tissue to a greater extent than in normal tissue. However, studies on the localization of integrin expression in cancer tissue, and co-relations of integrin over-expressions, with survival and drug sensitivity, must be followed to evaluate the clinical value of integrin expression.

Establishment of Three Dimensional in-vitro Culture System with Human Endometrial Cells: Induction of Differentiation by Sex Steroid Hormone & Characterization / 대한산부인과학회잡지

OBJECTIVE: The aim of this study was to establish three-dimensionally cultured endometrial cell model containing endometrial stromal cell (ESC), endometrial epithelial cell (EEC) and extracellular matrix (ECM) and to compare the morphological and biomolecular expression patterns of this model with mid-luteal endometrium in vivo. MATERIALS AND METHODS: The EEC and ESC was obtained from hysterectomy specimen and cultured separately. The EEC was overlayered in Matrigel layer on ESC embedded in collagen. The model had been cultured for 48 h in DMEM medium containing estrogen and progesterone. The ultrastructure was evaluated by electron microscopy. The expression of integrins, cyclooxygenases and matrix metalloproteinases were examined by immunohistochemistry and zymography. RESULTS: EEC in three-dimensional culture model grew with polarity and tight junction and desmosome between cells were found. The formation of pinopodes was also detected. In three-dimensionally cultured endometrial cell model, the expression of integrin alpha1, alpha4, beta3, MMP-1, -2, -3 and 9 was detected which was not expressed in monolayer culture of EEC, ESC or ESC embedded in collagen. CONCLUSION: The three-dimensionally cultured endometrial cell model possessed the morphological and biomolecular characteristics of in vivo endometrium of implantation period. These characteristics could be achieved by paracrine interactions between ESC and EEC. This model may contribute to the studies of differentiation of endometrium, process of implantation and pathophysiology of implantation-related diseases.

Actin binds to the cytoplasmic tail of alpha 1 subunit of integrin in hepatocytes.

alpha 1 beta 1-Integrin is a common receptor for laminin and collagen IV on hepatocytes. The interactions of intracellular domain of integrins with cytoplasmic elements are critical in the initiation and transduction of signals. In order to understand the nature of cytoplasmic components that can interact with cytoplasmic domain of alpha 1 integrin, cytoplasmic extracts of monolayers of rat hepatocytes were subjected to chromatography over an affinity column prepared by coupling a 60-mer synthetic cytoplasmic tail of alpha 1 subunit. SDS-PAGE analysis of the eluate showed the presence of a 47 kDa protein. Dot-Blot assay using radio-iodinated 47 kDa protein showed the binding of the protein to 60-mer C tail in a concentration dependent manner. Immunoblot analysis using specific antibodies showed that the 47 kDa protein is actin.

Expression Pattern of Progesterone Receptor, Integrin, Cyclooxygenase (COX) in Human Endometrium of Patients with Endometriosis / 대한불임학회지

OBJECTIVES: To develop a new immunohistochemical marker system for supplementation of the Noyes histological classification of the endometrium in women of child bearing age with regular menstrual cycles, and to employ this system to evaluate pathologic factors involved in endometriosis, and thus to ascertain if it is useful in diagnosis. MATERIALS AND METHODS: Endometrial biopsies were sampled from the posterior fundus of 41 (24 proliferative phases, 17 secretory phases) women with regular menstrual cycles (28-32 days), and each sample was immunhistochemically stained according to Noyes et al (1975) for determination of expression for extrogen receptor (ER), progesterone receter(PR), integrin alpha1, alpha4, beta3, COX-1 and COX-2. Then, the PR, the integrin beta3, and COX-2 which were clearly expressed in the luteal phase was with endometrial samples were obtained from 20 cases of normal patients (group 1) and 25 cases with endometriosis (group 2) after confirming the day of ovulation by sex steroid level measurements 7-8 days after ovulation. RESULTS: In the regular menstruation group the expression of ER showed a tendency to be increased in the proliferative phase and decreased in the secretory phase, and was the highest in the proliferative phase. However, PR in the stromal cells showed no change in the entire menstrual cycle while in the epithelial cells, PR reached a peak in the late proliferative phase and was almost absent in the secretory phase. Integrin alpha 1, alpha4, and beta3 expression in the epithelial cells was absent in the proliferative phase but alpha1 was expressed strongly in the early and mid secretory phases and disappeared in the late proliferative phase, while beta3, appeared after the mid secretory phase and continued to be expressed until the late secretory phase. Expression in the stromal cells was weak overall and did not show any cyclic pattern. COX-1 expression was shown as a cyclic pattern in the stromal and epithelial cells and was partcularly strongly expressed in the mid secretory phase of epithelial cells, and in the mid secretory and menstruation phase of stromal cells. In the endometrial epithelial cells there was strong expression during the entire cycle with stronger expression in the secretory phase compared to the prolferative phase. COX-2 was clearly expressed in the late proliferative, early and mid secretory phased in the stromal cells. No expression was observed in the proliferative phase of the epithelial cells, but which began to appear in the early secretory phase reaching a significant pattern from the mid secretory phase onwards. There was almost no expression in the stromal cells. In the cases with endometriosis showing normal endometrial maturation according to the Noyes classification, PR expression was increased while Integrin-beta3 expression was significantly decreased compared to the normal group. Also, COX-2 expression was slightly decreased in the stromal cells of patients with endometriosis while it was significantly increased in the stromal cells. CONCLUSION: Immunohistochemical markers can supplement the original Noyes classification of histological endometrial dating and therefore ascertain existing pathologic conditions. Particularly for patients with endometriosis with normally mature endometrial cells, changes in COX-2 and integrin expression patterns may assist in elucidating pathophysiologic mechanisms and therefore aid in the diagnosis of abnormal implantation conditions, and consequently determine a treatment modality.

Expression of Adhesion Molecules in Placenta and Correlation with Uterine Artery Doppler Velocimetry in Pregnancy-induced Hypertension / 대한산부인과학회잡지

INTRODUCTION: The pathophysiology of PIH remains unclear. Recently, placental abnormalitiesare stressed as a possible cause of PIH. Abnormal shallow invasion of trophoblasts, confinedto decidua, without involving myometrium is believed to result in reduced uteroplacentalperfusion, endothelial injury, and activation of coagulation cascade system. Integrin, one of theadhesive membrane proteins, is expected to be related to the regulation of trophoblasts invasion. PURPOSE: The purpose of this study is to investigate the expression of adhesion moleculesin placenta and the correlation between uterine artery Doppler findings and integrinexpressions in the placentas of PIH patients. SUBJECTS: Thirty-six cases of severe PIH patients were enrolled in the study with 10number of normal control pregnant women. The integrin subunit expressions withimmunohistochemical staining were observed in floating villi, maternal-side cytotropholbasts, andfetal-side cytotrophoblasts. Uterine artery Doppler study was also performed, and the S/Dratio was evaluated. Abnormal Doppler findings was defined as S/D ratio>or=2.6. RESULTS: Cytoplasmic staining of villi and placental bed cytotrophoblast for theintegrin alpha1 subunit in PIH specimen was weaker than those in normal controls. Theexpression of integrin beta1 subunit was negative for both controls and PIH group. Thepositive cytoplasmic stain was observed among PIH placenta in contrast to normal control inwhich the expression of integrin beta4 subunit was not detected. The expression of alpha v beta3 introphoblast with PIH was positive staining, but not in control group. Uterine artery Dopplervelocimetry was performed in 25 cases with PIH. Trace(+/-) or - staining of integrin alpha1 subunit were observed in 60.0% of abnormal S/D(>or=2.6) group, 20.0% of normal S/Dratio group patients, respectively. Trace or + staining of integrin beta4 subunit were observedin 50.0% of abnormal S/D group and 6.7% of normal S/D group and this is in statisticallysignificant. Trace or + staining of integrin alpha v beta3 subunit were observed 70.0% ofabnormal S/D group and 26.7% of normal S/D group, and this statistically significant. CONCLUSION: In PIH the abnormality in the invasion of cytotrophoblats results inabnormal integrin subunit expression, but it is also correlated to the abnormal uterine arteryDoppler velocimetry which shows a S/D ratio of greater than 2.6. Thus, the uterine arteryDoppler velocimetry reflects abnormal placentation.