Heat or radiofrequency plasma glow discharge treatment of a titanium alloy stimulates osteoblast gene expression in the MC3T3 osteoprogenitor cell line

PURPOSE: The purpose of this study was to determine whether increasing the Ti6Al4V surface oxide negative charge through heat (600degrees C) or radiofrequency plasma glow discharge (RFGD) pretreatment, with or without a subsequent coating with fibronectin, stimulated osteoblast gene marker expression in the MC3T3 osteoprogenitor cell line. METHODS: Quantitative real-time polymerase chain reaction was used to measure changes over time in the mRNA levels for osteoblast gene markers, including alkaline phosphatase, bone sialoprotein, collagen type I (alpha1), osteocalcin, osteopontin and parathyroid hormone-related peptide (PTH-rP), and the osteoblast precursor genes Runx2 and osterix. RESULTS: Osteoprogenitors began to differentiate earlier on disks that were pretreated with heat or RFGD. The pretreatments increased gene marker expression in the absence of a fibronectin coating. However, pretreatments increased osteoblast gene expression for fibronectin-coated disks more than uncoated disks, suggesting a surface oxide-mediated specific enhancement of fibronectin's bioactivity. Heat pretreatment had greater effects on the mRNA expression of genes for PTH-rP, alkaline phosphatase and osteocalcin while RFGD pretreatment had greater effects on osteopontin and bone sialoprotein gene expression. CONCLUSIONS: The results suggest that heat and RFGD pretreatments of the Ti6Al4V surface oxide stimulated osteoblast differentiation through an enhancement of (a) coated fibronectin's bioactivity and (b) the bioactivities of other serum or matrix proteins. The quantitative differences in the effects of the two pretreatments on osteoblast gene marker expression may have arisen from the unique physico-chemical characteristics of each resultant oxide surface. Therefore, engineering the Ti6Al4V surface oxide to become more negatively charged can be used to accelerate osteoblast differentiation through fibronectin-dependent and independent mechanisms.

The bone formation around anodic oxidized titanium implants in the tinbiae of ovarectomized rats

Anodic spark deposition method(ASD) surface treated titanium implant possesses a considerable osteoconductive potential that promoting a high level of implant osseointegration in normal bone. The purpose of this study was to observe the ASD implant's osseointegration in the osteoporosis-induced animal model. Twenty four rats, 10 weeks of age, were ovarectomized and 5 weeks later divided into two groups : ASD implant group and control implant group. Titanium screw implants (diameter; 2.0 mm, length, 3.5 mm; pitch-height, 0.4 mm) were designed for this study. Experimental implants were ASD treated and no treatment on control implants. ASD implants and control implants were placed in to left tibiae of rats. The rats were sacrificed at different time interval(1, 2, 4 and 8 weeks after implantation) for histopathologic observation and immunohisto -chemistrical observation, with collagen type I, fibronectin, integrin alpha2beta1 and integrin alpha5beta1 antibodies. The results obtained from this study were as follow: 1. Histopathologic findings, overall tissue response and the pattern of bone formation in both groups were similar. In ASD group, more newly formed bone was seen at 1 week and 2weeks than control group. 2. The levels of type I collagen and fibronectin expression were the most abundant at 2weeks and decreased gradually in both groups. Fibronectin and type I collagen expression in ASD group were stronger than control group but no significance. 3. The levels of integrin alpha2beta1 and Integrin alpha5beta1 expression were most abundant at 2 weeks and decreased gradually in both groups. No significant difference was observed in both groups. From this results, anodic oxidized titanium implants were more advantages in early stage of bone formation than control group, but have no significance in tissue responses and late bone formations. It could be stated that although anodic oxidized titanium implant possesses considerable osteoconductive potential but in osteoporotic bone condition dental implant procedure should performed after improving or treating the osteoporotic bone condition.

T-CAM, a fastatin-FIII 9-10 fusion protein, potently enhances anti-angiogenic and anti-tumor activity via alphavbeta3 and alpha5beta1 integrins

We made fusion protein of fastatin and FIII 9-10, termed tetra-cell adhesion molecule (T-CAM) that can interact simultaneously with alphavbeta3 and alpha5beta1 integrins, both playing important roles in tumor angiogenesis. T-CAM can serve as a cell adhesion substrate mediating adhesion and migration of endothelial cells in alphavbeta3 and alpha5beta1 integrin-dependent manner. T-CAM showed pronounced anti-angiogenic activities such as inhibition of endothelial cell tube formation, endothelial cell proliferation, and induction of endothelial cell apoptosis. T-CAM also inhibited angiogenesis and tumor growth in mouse xenograft model. The anti-angiogenic and anti-tumoral activity of molecule like fastatin could be improved by fusing it with integrin-recognizing cell adhesion domain from other distinct proteins. The strategy of combining two distinct anti-angiogenic molecules or cell adhesion domains could facilitate designing improved anticancer agent of therapeutic value.

Parallel changes in fibronectin and alpha5beta1 integrin in articular cartilage in type II collagen-induced arthritis.

Interactions of cells with extracellular matrix (ECM) are mediated through specific cell surface receptors, belonging to the integrin family of transmembrane proteins. Integrins have been shown to be involved in chondrocyte-matrix interactions in the cartilage. In this study, the status of a matrix glycoprotein fibronectin (FN) and its receptor alpha5beta1 integrin in the articular cartilage in collagen type II-induced experimental arthritis in rats, as well as in synovial fluid from osteoarthritic patients was investigated. Experimental arthritis was induced by intradermal injection of type-II collagen (300 microg/100 g body wt) and Freund's complete adjuvant. Saline-treated animals served as control. Clinical severity was indicated by increase in paw volume. Significant increase in the activities of lysosomal enzymes beta-glucuronidase and beta-hexosaminidase was observed in synovial effusate, serum and cartilage of arthritic animals, when compared to untreated control, indicating dysfunction of cartilage. Changes in FN and alpha5beta1 integrin were studied by ELISA. A progressive increase was observed in the FN level in synovial effusate and cartilage of arthritic animals, when compared to untreated controls. FN levels were also significantly high in synovial fluid of osteoarthritic patients. A significant increase in the levels of alpha5beta1 integrin was found in cartilage of arthritic rats. Parallel changes in FN and alpha5beta1 integrin indicated that alterations in FN and alpha5beta1 integrin in chondrocytes constituted one of the molecular mechanisms during progression of arthritis.

Correlation between integrin subunits alpha5 and beta1 expressions in prostate cancer and its clinical implication / 中华男科学杂志

<p><b>OBJECTIVE</b>To explore the correlation between the expression of integrin subunits alpha5 and beta1 in prostate cancer (PCa) and its clinicopathological data including tumor grade and clinical stage.</p><p><b>METHODS</b>Expressions of integrin subunits alpha5 and beta1 were examined in 30 cases of PCa and 30 cases of normal prostatic tissues by immunohistochemical assay.</p><p><b>RESULTS</b>Expressions of integrin subunits alpha5 and beta1 in PCa were lower than those in normal prostatic tissues (P <0.05) respectively.</p><p><b>CONCLUSION</b>Compared with normal prostatic tissues, expressions of integrin subunits alpha5 and beta1 in PCa were rather weaker or even faded. Expressions of integrin subunits alpha5 and beta1 revealed an positive correlation with tumor's Gleason grade and negative with clinical TNM stage. The results indicate that integrin subunits alpha5 and beta1 have potential values in the diagnosis and are predictable indices in the proliferation of PCa.</p>

Effect of epidermal growth factor signal pathway on integrin alpha5 beta1 in prostate cancer cell line DU145 / 中华外科杂志

<p><b>OBJECTIVE</b>To investigate the molecular mechanism of epidermal growth factor (EGF) signal pathway on the expression of integrin alpha5 beta1 in prostate cancer cell line DU145.</p><p><b>METHODS</b>Using flow-cytometry, the effects of EGF and the mitogen-activated protein kinase (MAPK) signal pathway inhibitor PD98059 on the expression of integrin alpha5 and beta1 subunits on DU145 cell surface were analyzed. RT-PCR and Western blot methods were used to examined the expression of mRNA and cell total protein of integrin alpha5 and beta1 subunits. And the metastatic phenotypes in DU145 cell were investigated.</p><p><b>RESULTS</b>The expression levels of integrin alpha5 beta1, which was the receptor for fibronectin, were changed. EGF up-regulated the protein and mRNA expression of beta1 subunit on DU145 cell surface, 231% and 248% (P < 0.01) compared to the control respectively, and it could significantly promote the ability of DU145 cell adhesion to fibronectin and migration. However PD98058, which was the inhibitor of MAPK signal pathway, down-regulated the protein and mRNA expression of beta1 subunit, 60% and 63% (P < 0.01) compared to the control respectively, and it had the contrary function on the adhesion and migration ability of DU145 cell. But both had no effect the expression of alpha5 subunit.</p><p><b>CONCLUSIONS</b>EGF might promote the metastatic ability mainly by up-regulating the expression of beta1 subunit by activating MAPK signal pathway in DU145 cells. Their regulation effects are on the mRNA transcriptional level.</p>

Expression and significance of integrin alpha5, beta1 and E-CD in patients with non-small cell lung carcinoma / 中华肿瘤杂志

<p><b>OBJECTIVE</b>To investigate the relationship between the expressions of integrin alpha5 beta1 and E-CD, and clinicopathological characteristics and prognosis of patients with non-small cell lung carcinoma (NSCLC).</p><p><b>METHODS</b>The expression of integrin alpha5 beta1 and E-CD were analyzed in 53 NSCLC and 12 control specimens by immunohistochemical assay.</p><p><b>RESULTS</b>The expression of integrin alpha5 beta1 was significantly higher in NSCLC (58.5%) than that in normal lung tissue (16.7%), and also positively related with pathological characteristics (P = 0.021), lymph node metastasis (P = 0.006), and clinical stage (P = 0.002). The 3-year survival rate in NSCLC group was significantly lower than that in control group (22.3% vs 40.6% , P = 0.041). The positive expression of E-CD in NSCLC and control group was 32.1% and 91.7%, respectively, and negatively correlated with pathological characteristics (P = 0.010) and lymph node metastasis (P = 0.002). The 3-year survival rate in control group was 19.9%, lower than that in NSCLC group (41.2%, P > 0.05), but the difference is not significant.</p><p><b>CONCLUSION</b>The overexpression of integrin alpha5 beta1 may contribute to lymph node metastasis and play an inverse role, while E-CD may be a beneficial prognostic factor in patients with NSCLC.</p>

Expression and significance of alpha5beta1 integrin in abnormal scars / 中华整形外科杂志

<p><b>OBJECTIVE</b>To study the expression of alpha5beta1 integrin in the abnormal scars and its role and significance in the formation and development of abnormal scars.</p><p><b>METHODS</b>The expression of alpha5beta1 integrin was observed in hypertrophic scar (15 samples), keloid (15 samples) and normal skin (10 samples) with SP immunohistochemical method and colloidal gold immuno-electron microscopic technique. The data were semi-quantitatively analyzed.</p><p><b>RESULTS</b>The expression levels of alpha5beta1 integrin in the fibroblasts of keloids and hypertrophic scars were higher than normal skin; the expression of alpha5beta1 integrin in the fibroblasts of keloids was higher than hypertrophic scars (P < 0.01).</p><p><b>CONCLUSION</b>The alpha5beta1 integrin appears to have close relation to the formation and development of abnormal scars. To find a way to decrease the expression level of alpha5beta1 integrin in fibroblasts may be a new approach to inhibit scar hypertrophy.</p>

Effect of Recombinant Fragment of Fibronectin on the Cellular Functions of Human Bone Marrow-Derived Mesenchymal Stem Cells / 대한정형외과연구학회지

PURPOSE: We investigated the effects of recombinant 9-10th type III repeat of fibronectin (rhFNIII9-10) on the adhesion, proliferation, and the osteogenic differentiation of human bone marrow-derived mesenchymal stem cells(hMSCs). MATERIALS AND METHODS: Adhesion and blocking assay for hMSCs were performed on the plates which had been coated with 100 microgram/ml rhFNIII9-10 or fibronectin. hMSCs seeded on the precoated plates were cultured in the osteogenic media for 3 weeks. MTS(Dimethylthiazole carboxymethoxyphenyl sulfophenyl tetrazolium compound) assay for the cell number, [Methyl-3H] thymidine incorporation study, alkaline phosphatase activity assay, calcium content assay and RT-PCR for alkaline phosphatase, osteopontin, cbfa-1, and type I collagen were performed during the osteogenic differentiation. RESULTS: hMSCs showed significantly increased adhesion to rhFNIII9-10-coated plates and fibronectin-coated plates. A monoclonal antibody to the integrin alpha 5 beta 1 inhibited adhesion to rhFNIII9-10-coated plates and fibronectin-coated plates in dose-dependent manner. hMSCs seeded on the rhFNIII9-10-coated plates showed increased proliferation during the osteogenic differentiation. However, there was no significant difference in the alkaline phosphatase activity, calcium content and expression levels of mRNAs for alkaline phosphatase, osteopontin, cbfa-1, and type I collagen of hMSCs seeded on the rhFNIII9-10-coated plates. CONCLUSION: rhFNIII9-10 stimulates hMSCs adhesion and increases hMSCs proliferation during the osteogenic differentiation. Although osteogenic differentiation is not promoted, adsorption of rhFNIII9-10 onto appropriate biomaterials can enhance integrin-mediated hMSCs adhesion and proliferation. This biomolecular engineering strategy represents a robust approach to increase biofunctional activity and integrin specificity of hMSCs.

Stem Cells Expressing Homing Receptors Could be Expanded From Cryopreserved and Unselected Cord Blood

We assessed the cytokine combinations that are best for ex vivo expansion of cord blood (CB) and the increment for cell numbers of nucleated cells, as well as stem cells expressing homing receptors, by an ex vivo expansion of cryopreserved and unselected CB. Frozen leukocyte concentrates (LC) from CB were thawed and cultured at a concentration of 1x10(5)/mL in media supplemented with a combination of SCF (20 ng/mL)+TPO (50 ng/mL)+FL (50 ng/mL)+/-IL-6 (20 ng/mL)+/-G-CSF (20 ng/mL). After culturing for 14 days, the expansion folds of cell numbers were as follows: TNC 22.3+/-7.8~26.3+/-4.9, CFU-GM 4.7+/-5.1~11.7+/-2.6, CD34+CD38- cell 214.0+/-251.9~464.1+/-566.1, CD34+CXCR4+ cell 4384.5+/-1664.7~7087.2+/-4669.3, CD34+VLA4+ cell 1444.3+/-1264.0~2074.9+/-1537.0, CD34+VLA5+ cell 86.2+/-50.9~ 113.2+/-57.1. These results revealed that the number of stem cells expressing homing receptors could be increased by an ex vivo expansion of cryopreserved and unselected CB using 3 cytokines (SCF, TPO, FL) only. Further in vivo studies regarding the engraftment after expansion of the nucleated cells, as well as the stem cells expressing homing receptors will be required.

Expression and regulation of integrin receptors in human trophoblast cells: role of estradiol and cytokines.

Embryo implantation and placentation are dynamic cellular events that require not only synchrony between the maternal environment and the embryo, but also complex cell-cell communication amongst the implanting blastocyst and the receptive endometrium through integrins, a large family of proteins involved in the attachment, migration, invasion and control of cellular functions. Integrins display dynamic temporal and spatial patterns of expression by the trophoblast cells during early pregnancy in humans. However, the precise mechanism of embryo implantation and the modulation of the integrin receptors during blastocyst attachment and further implantation remain elusive in the humans. The present study elucidates the expression and hormonal modulation of fibronectin, vitronectin and laminin integrin receptors by estradiol and IL-1alpha in human trophoblast cells. Human first trimester trophoblast cells showed the induction of the classical estrogen receptor (ER)-alpha by its own ligand, estradiol. Treatment with either estradiol or IL-1alpha induced the expressions of alpha4, alpha5, alpha6 and alpha(v) integrin receptor subunits at both the mRNA and protein levels, while expression of beta1 remained unaltered. Furthermore, estradiol upregulated the expression of IL-1alpha, thereby suggesting the possibility that estrogen may either directly or via the proinflammatory cytokine induces the expression of the cell surface integrin receptors. The findings delineate the role of hormones and the cytokines in modulating the adhesiveness and attachment of the trophoblast cells. This may reflect the in vivo scenario where the implanting embryo is surrounded by a hormone-cytokine rich uterine microenvironment that may precisely regulate the expression of integrins and thereby facilitate implantation.

Restoring beta1 integrin activation function in K562 cells transfected with antisense VEGF121 cDNA / 中国实验血液学杂志

To investigate the effect of vascular endothelial growth factor (VEGF) on beta1 integrin (VLA-4 and VLA-5) activation ability in K562 cells transfected with antisense VEGF121 cDNA, K562 cells were transfected with antisense (As), sense (S) and vector (V, pcDNA(3)). Flow cytometry was used to evaluate the expression rate of VLA-4 (CD49d/CD29) and VLA-5 (CD49e/CD29) and beta1 integrin activation ability in the transfected K562 cells. The results showed that the expression rates of VLA-4 and VLA-5 were more than 92% in the transfected K562 cells and there was no difference among the K562/V, K562/S and K562/As cells. However, beta1 integrin activated 9EG7 expression rate in K562/As cells was higher than that in K562/V cells [(75.6 +/- 10.5)% vs (41.2 +/- 2.1)%, P < 0.01)] after activation with beta1 integrin activator 8A2. It is concluded that function of beta1 integrin to be activated is restored in K562 cells transfected with antisense VEGF121 cDNA.

A Case of Ullrich's Disease

Ullrich's disease is a congenital muscular dystrophy clinically characterized by generalized muscle weakness, multiple contractures of the proximal joints, and hyperextensibility of the distal joints. All the patients develop rigidity of spine, often assoicated with scoliosis, failure to thrive, and early and severe respiratory involvement, irrespective of their levels of motor function. Intellectual development is normal. The biopsied muscles show dystrophies including remarkable variation in the fiber size, notably proliferated endomysial connective tissues, and a lot of degenerated and regenerated fibers. The expression of merosin and dytrophin is normal. Recent studies have demonstrated that collagen VI is deficient in the muscles of the patients with Ullrich's disease, and some result from recessive mutations of the collagen VIalpha 2 gene(COL6A2). And a marked reduction of fibronectin receptors in the extracellular matrix of skin and cultured fibroblasts of these patients is also reported. These results suggest that collagen VI deficiency may lead to the reduction of fibronectin receptors and that any abnormalities of cell adhesion may be involved in the pathogenesis of the disease. A case of Ullrich's disease has not been reported yet in Korea. So, we describe a male patient with Ullrich's disease with a brief review of the literature.

Integrins Mediating Adhesion and Proliferation of ADP-stimulated Vascular Smooth Muscle Cells

BACKGROUND AND OBJECTIVES: Adenosine diphosphate (ADP), which is usually secreted from activated platelets, may activate integrins on vascular smooth muscle cells, resulting in adhesion and proliferation. Integrins, mediating the ADP-stimulated adhesion and proliferation of vascular smooth muscle cells, was investigated in this study. MATERIALS AND METHODS: Prothrombin (PT) and bone sialoprotein (BSP) were used as activation-dependent ligands in an adhesion assay. The adhesion of human aortic smooth muscle cells (HASMC) were measured after ADP stimulation, using ligand-coated 24-well plates. The 3-[4, 5-dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide (MTT) assay was used to evaluate the ADP-stimulated proliferation of the HASMC.RESULTS: ADP activated the HASMC to increase their adhesion to the PT or BSP, and their proliferation in a dose-dependent manner. The adhesion of the ADP-stimulated HASMC to the PT was completely blocked by P5H9, a blocking monoclonal Ab (mAb) to integrin alphavbeta5 (92% inhibition), but was only slightly inhibited by LM609, a blocking mAb to integrin alphavbeta3 (30% inhibition). The adhesion of the ADP-stimulated HASMC to the BSP was partially inhibited by both P5H9 (46% inhibition) and JBS5, a blocking mAb to integrin alpha5beta1 (75% inhibition), but was not affected by c7E3, a blocking mAb to integrin beta3. The ADP-stimulated proliferation of the HASMC was inhibited by both c7E3 and LM609 (98% and 93% inhibition, respectively), but not by either P1F5, a blocking mAb to integrin alphavbeta5 or JBS5. CONCLUSION: These results indicate the different roles of integrins on vascular smooth muscle cells after ADP stimulation; the integrins alphavbeta5 and alpha5beta1 for adhesion, and the integrin alphavbeta3 for proliferation.

The Effects of Hantaan Virus on Fibronectin and Matrix Metalloproteinase-3

The clinical symptoms and signs of hemorrhagic fever with renal syndrome (HFRS) are well known, but the pathophysiology caused by Hantaan virus is not fully understood yet. This study was designed to evaluate the effect of Hantaan virus on the regulation of extracellular matrix proteins. The changes of fibronectin, fibronectin receptor (alpha5beta1 integrin), the matrix metalloproteinase-3 (MMP-3), and tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) in Vero E6 cell line were observed. Hantaan virus induced the mRNA expression of fibronectin at day 7 after the infection but the surface expression of fibronectin receptor (alpha5beta1 integrin) was reduced. The mRNA expression of MMP-3 was increased at day 5 by 8-fold in the virus infected cells compared with the control cells, and continued to increase until day 9. However, the mRNA expression of TIMP-1 did not show any significant changes. The concentration of plasma fibronectin in the HFRS patients was measured by ELISA. The fibronectin levels were variable and could be divided into three groups: low (14.8%), normal (62.9%) and high (22.2%) groups in comparison with normal range value. These results suggest that Hantaan virus should affect not only the infected cell itself but also the extracelluar matrix, which might play an important role in the pathogenesis.

Stem cell factor enhances the adhesion of hematopoietic cells to fibronectin / 中国实验血液学杂志

Adhesion to extracellular matrix plays important roles in the regulation of survival, proliferation, differentiation and homing of hematopoietic cells and is regulated by a wide variety of growth factors, adhesion receptors and other ligands that mediate the cell to matrix and cell to cell interaction. Stem cell factor (SCF) plays important roles in the regulating growth and self-renewal of hematopoietic stem/progenitor cells. In the report, the effects of stem cell factor on the adhesion of hematopoietic cells to fibronectin were observed by using a hematopoietic growth factor dependent cell line-Mo7e. Results showed that Mo7e cells express the very late antigen VLA-4 (beta1 alpha4) and VLA-5 (beta1 alpha5) integrins. The expression of the SCF receptor (c-kit) was also detected in the Mo7e cells. SCF enhances the adhesion of Mo7e cells to fibronectin in a concentration dependent manner. SCF enhanced adhesion of Mo7e cells to fibronectin was blocked by anti-beta1, alpha4 and alpha5 antibodies. Addition of PI-3 kinase inhibitors also blocked the adhesion of Mo7e cells to fibronectin induced by SCF. It was concluded that SCF enhances the adhesion of Mo7e cells to fibronectin, and this process is mediated by integrins and PI-3 kinase pathway.

The Supressive Effects of Integrin Antibodies on the Infection of Hantaan Virus in Fibroblasts / 영남의대학술지

Pathophysiological mechanism of hemorrhagic fever with renal syndrome (HFRS) is not fully understood. Major clinical findings of HFRS patients are widespread hemorrhage, acute renal failure and shock. Basic lesion is vascular injury with microvascular hemorrhage and relatively little inflammation. According to autopsy findings, renal medulla shows focal hemorrhage, tubular necrosis and interstitial mononuclear infiltrates. The predominant cell type in the renal and pulmonary interstitium is a fibroblast and it participates in the healing process at the injury site by secreting a large amount of extracellular matrix proteins. Cultured human lung fibroblasts and Mongolian gerbil fibroblasts were known to be good host cells for the hantaan virus. It is possible that not only the endothelial cell but also the fibroblast is a target of Hantaan virus and the fibroblast might be involved in the pathogenesis and the healing process in HFRS. Integrins are adhesion molecules, and act as receptors for many extracellular matrix proteins. Recently, there are many reports that cell surface integrins influence on some viral infections or reversely viruses influence on the expression of integrins. The alpha5beta1 integrin is a major receptor for the fibronectin which is an important extracellular matrix protein secreted by fibroblasts. In this study, the role of alpha5beta1 integrin in the infection of Hantaan virus was examined by using anti-alpha5beta1 integrin, anti-alpha5 integrin and anti-beta1 integrin antibodies in chicken embryo fibroblasts (CEF) and Mongolian gerbil fibroblasts(MGF). The treatment of anti-alpha5beta1 integrin antibody in CEF reduced the virion titers 26.8% and the amount of nucleocapsid N protein 32.6% when compared with control CEF. When MGF were treated with anti-alpha5, anti-beta1 and anti-alpha5beta1 integrin antibodies, virion titers were reduced by 26.5%, 29.4% and 28.7% and the amount of nucleocapsid N protein were reduced by 65.2%, 59.7% and 72.6%. These results suggested that alpha5beta1 integrin might act as a receptor for the Hantaan virus or blocking of alpha5beta1 integrin influences on the viral replication in CEF and MGF. It is also possible that the blocking of only one subunit of integrin represents similar results in that of whole molecule.

The Role of alpha5beta1 Integrin on Infection of Hantaan Virus in Fibroblasts

Pathophysiological mechanism of hemorrhagic fever with renal syndrome(HFRS) is not fully understood. Major clinical findings of HFRS patients are widespread hemorrhage, acute renal failure and shock. Basic lesion is vascular injury with microvascular hemorrhage and relatively little inflammation. According to autopsy findings, renal medulla has focal hemorrhage, tubular necrosis and interstitial mononuclear infiltrates. Hantavirus pulmonary syndrome(HPS) caused by Sin Nombre virus which is known as a member of Hantavirus genus, characterized by rapidly progressive pulmonary edema, hypotension and interstitial pulmonary infiltrate with lymphocytes. The predominant cell type in the renal and pulmonary interstitium is a fibroblast and it participates in the healing process at injury site by secreting a large amount of extracellular matrix proteins. Cultured human lung fibroblasts and Mongolian gerbil fibroblasts were known as the good host cells to the hantaan virus. It is possible that not only endothelial cell but also fibroblast is a target of Hantaan virus and the fibroblast might be involved in the pathogenesis and the healing process in HFRS. Integrins are an adhesion molecule, and act as the receptors for many extracellular matrix proteins. Recently, there are many reports that cell surface integrins influence on some viral infections or reversely viruses influence on the expression of integrins. The alpha5beta1, integrin is a major receptor for the fibronectin which is an important extracellular matrix protein secreted by fibroblasts. In this study, the role of alpha5beta1 integrin on the infection of Hantaan virus was examined by using an anti-alpha5beta1 integrin antibody in chicken embryo fibroblasts(CEF) and Mongolian gerbil fibroblasts(MGF). CEF and MGF were treated with anti-alpha5beta1, integrin antibody during 30 minutes before viral infection and the culture supernatants were harvested 5 days after virus infection. The treatment of anti-alpha5beta1 integrin antibody on CEF reduced the viral titers about 30% when compared with the non-antibody treatment control CEF. In MGF, these viral titers were reduced by 36% and 68% according to the assay methods by FFU and ELISA, respectively. These results suggested that alpha5beta1 integrin might be act as a receptor for the Hantaan virus or blocking of alpha5beta1 integrin influence on the viral replication in CEF and MGF. To find out which suggestion is related with, further studies are going on.

Vla-Integrin Exprfs Ion In Articular Cartilage / 대한류마티스학회지

OBJECTIVE: The adhesion molecule that mediate cell-cell and cell-extracellular matrix adhes.ion provides very important role in growth and differentiation of cells and tissue. VLA integrin is a prototype of adhesion molecule which participate in cell-cell and cell-extracellular matrix interacton, especially for collagen, laminin and fibronectin. The biologic functions of VLA-integrin are very diverse. Cartilage is the target tissue of various arthritides including rheumatoid arthritis and osteoarthritis and the process of homeostasis in cartilage matrix may be very important in preservation of cartilage. Although VLA integrin may participate in the process of cartilage degeneration and repair mechanism, tissue.distribution and exact role of VLA integtin in cartilage was not yet clearly defined. METHODS:Immunohistochemical analysis of VLA-integrin in cryostat section of articular cartilage was conducted using monoclonal antibody and avidin-biotin complex method. Analysis was performed in 10 rheumatoid arthritis specimens, 7 osteoarthritis specimens and 1 normal control. RESULTS: 1) Normal cartilage showed strong and diffuse stain with CD29, CD51 and moderate stain of VLA-5. Staining pattern of VLA-1 and 3 was inconstant and weak in intensity. 2) The intensity of VLA expression in articular cartilage of osteoarthritis was upregulated chiefly in CD29, CD51 and slightly in VLA-5. The positive rate of VLA-1 and 3 was similar to that of normal cartilage though the intensity was increased especially at cluster of chondrocytes. 3) VLA-integrin expression of rheumatoid arthritis cartilage was similar to that of osteoarthritis cartilage. CONCLUSION: VLA integrins functioning as fibronectin receptor such as VLA-5 and alpha, beta1 were upregulated in osteoarthritis and rheumatoid arthritis. Intensity was increased at clusters of chondrocytes. It was able to presume from above findings that VLA molecule has some role in the maintenance and repair of articular cartilage. The regulation of expression by cytokines and growth factors and exact function of VLA molecule in cartilage have to be elucidated.