• BMB Reports
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• v.33 no.4
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• pp.349-352
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• 2000

Proteins that are involved in cellular signal cascade experience phosphorylation and dephosphorylation cycles in their tyrosine residue(s) during cell adhesion. In order to identify the protein(s), which tyrosine desidues are specifically phosphorylated when the cells attached to the substrate, we compared the tyrosine phosphorylation level of proteins between suspension and adhered culture condition in rat fibroblast 3Yl cells. We found that a cluster of 70 kDa protein was specifically phosphorylated when the cells adhered to the substrate, but did not effect the cells held in suspension. The phosphorylated protein is identified as paxillin, a focal adhesion protein in immunoprecipitation and immunobloting analysis. These results suggest that the tyrosine phosphorylation of paxillin may play a role in cell-substrate adhesion.

• Macromolecular Research
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• v.9 no.4
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• pp.197-205
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• 2001

Platelet adhesion onto elastic polymeric biomaterials was tested in vitro by perfusing human whole blood at a shear rate of 100 sec$\^$-1/ for possible verification of mechanisms of initial platelet adhesion perfusion of blood on the polymeric substrates was performed after treatments either with or without pre-adsorption of 1% blood plasma, and either with or without residence of the protein-preadsorbed substrate in phosphate buffered solution. The surfaces employed were elastic polymers such as poly(ether urethane urea), poly(ether urethane), silicone urethane copolymer, silicone rubber and poly(ether urethane) with the anti-calcifying agent hydroxyethane bisphosphate. Each polymer surface treated was exposed in vitro to the dynamic, heparinized whole blood perfused for upto 6 min and the surface area of platelets initially adhered was measured by employing in situ epifluorescence video microscopy. The blood perfusion was performed on the surfaces treated at the following three different conditions: directly on the bare surfaces, after protein pre-adsorption and after residence in buffer for 3 days of the surfaces protein pre-adsorbed for 2 h. The effects of blood plasma pre-adsorption on the initial platelet adhesion was surface-dependent. The amount of the adsorbed fibrinogen and the surface coverage area of the adhered platelets were dependent on the surface conditions whether substrates were bare surfaces or protein pre-adsorbed ones. To test an effect of possible morphological (re)orientations of the adsorbed proteins on the initial platelet adhesion, the polymeric substrate pre-adsorbed with 1% blood plasma was immersed in phosphate buffered solution for 3 days and then exposed to physiological blood perfusion. The surface area of the platelets adhered on these surfaces was significantly different from that of the surfaces treated with protein pre-adsorption only. These results indicated that platelet adhesion was dependent on the surface property itself and pre-treatment conditions such as blood perfusion without any pre-adsorption of proteins, and blood perfusion either after protein pre-adsorption or after subsequent substrate residence in buffer of the substrate pre-adsorbed with proteins. Understanding of these results may guide for better designs of blood-contacting materials based on protein behaviors.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.33 no.5
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• pp.445-454
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• 2007

Background: Phosphatidic acid(PA), an important second messenger, is involved in inflammation. Notably, cell-cell interactions via adhesion molecules playa central role in inflammation. This thesis show that PA induces expression of intercellular adhesion molecule-1(ICAM-1) on macrophages and describe the signaling pathways. Materials and methods: Macrophages were cultured in the presence of 10% FBS and assayed cell to cell adhesion using HUVEC. For the gene and protein analysis, RT-PCR, Western blot and flow cytometry were performed. In addition, overexpressed cell lines for dominant negative PKC-${\delta}$ mutant established and tested their effect on the promoter activity and expression of ICAM-1 protein by PA. Results: PA-activated macrophages significantly increased adhering to human umbilical vein endothelial cell and this adhesion was mediated by ICAM-1. Pretreatment with rottlerin(PKC-${\delta}$ inhibitor) or expression of a dominant negative PKC-${\delta}$ mutant, but not Go6976(classical PKC-${\alpha}$ inhibitor) and myristoylated PKC-${\xi}$ inhibitor, attenuated PA-induced ICAM-1 expression. The p38 mitogen-activated protein kinase(MAPK) inhibitor blocked PA-induced ICAM-1 expression in contrast, ERK upstream inhibitor didn't block ICAM-1. Conclusion: These data suggest that PA-induced ICAM-1 expression and cell-cell adhesion in macrophages requires PKC-${\delta}$ activation and that PKC-${\delta}$ activation is triggers to sequential activation of p38 MAPK.

• Biomaterials and Biomechanics in Bioengineering
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• v.3 no.1
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• pp.59-69
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• 2016

A surface resisting protein adsorption and cell adhesion is highly desirable for many biomedical applications such as diagnostic devices, biosensors and blood-contacting devices. In this study, a surface conjugated with sulfobetaine molecules was fabricated via the click reaction for the anti-fouling purpose. An alkyne-containing substrate (Alkyne-PPX) was generated by chemical vapor deposition of 4-ethynyl-[2,2]paracyclophane. Azide-ended mono-sulfobetaine molecules were synthesized and then conjugated on Alkyne-PPX via the click reaction. The protein adsorption from 10% serum was reduced by 57%, while the attachment of L929 cells was reduced by 83% onto the sulfobetaine-PPX surface compared to the protein adsorption and cell adhesion on Alkyne-PPX. In conclusion, we demonstrate that conjugation of mono-sulfobetaine molecules via the click chemistry is an effective way for reduction of non-specific protein adsorption and cell attachment.

• Journal of Korean Dental Science
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• v.8 no.2
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• pp.74-81
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• 2015

Purpose: In osteoclast differentiation, actin-rich membrane protrusions play a crucial role in cell adhesion. Odontogenic ameloblast-associated protein (Odam) contributes to cell adhesion by inducing actin rearrangement. Odam-mediated RhoA activity may play a significant role in multinucleation of osteoclasts. However, the precise function of Odam in osteoclast cell adhesion and differentiation remains largely unknown. Here, we identify a critical role for Odam in inducing osteoclast adhesion and differentiation. Materials and Methods: The expression of Odam in osteoclasts was evaluated by immunohistochemistry. Primary mouse bone marrow and RAW264.7 cells were used to test the cell adhesion and actin ring formation induced by Odam. Result: Odam was expressed in osteoclasts around alveolar bone. Odam transfection induced actin filament rearrangement and cell adhesion compared with the control or collagen groups. Overexpression of Odam promoted actin stress fiber remodeling and cell adhesion, resulting in increased osteoclast fusion. Conclusion: These results suggest that Odam expression in primary mouse osteoclasts and RAW264.7 cells promotes their adhesion, resulting in the induction of osteoclast differentiation.

• Journal of Life Science
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• v.18 no.7
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• pp.952-957
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• 2008

We evaluated the effects of various factors (e.g., serum, inhibitors of protein synthesis, and cytoskeleton and protein kinases) on early PMA-induced THP-1 cell adhesion using an adhesion assay with Sulforhodamine B (SRB) staining, which was used to assess the proliferation of the attached cells. THP-1 cell adhesion to a plastic substrate was detected 1 hr after exposure to Phorbol 12-Myristate 13-Acetate (PMA) and peaked after 18 hr. At concentrations > 25 nM PMA, the level of adhesion did not change. Based on our preliminary results, we used 25 nM PMA and 5 hr of culture as standard assay conditions. Early PMA-induced cell adhesion was not affected by the presence of serum or PD 98059 in the culture medium, but was affected by the addition of PKC inhibitors and cycloheximide. In the presence of actin inhibitor with PMA, the cell adhesion increased when comparing with PMA treatment only. Thus, early PMA-induced adhesion of THP-1 cells does not require serum in the culture medium, MAP-kinase activation, or actin polymerization, but does require de novo protein synthesis and PKC activation. Our SRB-based cell adhesion assay may be used to screen other PKC inhibitors.

• Proceedings of the Korean Magnetic Resonance Society Conference
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• 1999.02a
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• pp.23-23
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• 1999

• Journal of Microbiology and Biotechnology
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• v.13 no.6
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• pp.853-858
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• 2003

Helicobacter pylori specifically adhere to host cells through a number of putative receptors and ligands, mainly based on carbohydrate-protein interactions. Polysaccharide fractions isolated from the leaves of Artemisia capillaris showed different inhibitory activities against H. pylori adhesion by using hemagglutination assay. Among these fractions, an acidic polysaccharide fraction FlA showed highly effective inhibitory activity, and its minimum inhibition concentration was 0.63 mg/ml. The inhibition results by the hemagglutination assay were consistent with those obtained by the enzymelinked glycosorbent assay, which was developed by the conjugation of horseradish peroxidase with fetuin, a sialic acid-containing glycoprotein which was specific to H. pylori adhesion. FlA contained the highest carbohydrate content among polysaccharide fractions, and no protein was detectable when further purified by gel filtration FPLC. Sugar composition analysis using GC revealed the highest amount of galacturonic acid among sugars, which suggests that FlA contains essentially acidic polysaccharides. Our data suggest that acidic polysaccharides may play an important role in the inhibition of H. pylori adhesion to host cells.

• YAKHAK HOEJI
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• v.52 no.1
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• pp.48-55
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• 2008

CD29 $({\beta}1-integrins)$ is one of major adhesion molecules involved in regulating cell adhesion, migration and morphological changes. In this study, we investigated the regulatory role of CD29 in monocytic functions using monocytic cell line U937 cells. CD29 was found to be one of highly expressed membrane proteins in U937 cells, according to flow cytometric analysis. The activation of CD29 by agonistic antibody MEM101A and extracellular matrix protein (ECM) fibronectin strongly induced cell-cell and cell-fibronectin adhesions. However, blocking antibodies to CD98 and CD147 showed different inhibitory features in these two adhesion events. Furthermore, U0126, an ERK inhibitor, only blocked cell-cell adhesion but not cell-fibronectin adhesion, indicating that cell-cell or cell-fibronectin adhesion events may be regulated by different molecular mechanisms. Meanwhile, CD29 activation also enhanced ROS generation but not phagocytic ability, and similarly radical scavenger N-acetyl-L-cysteine strongly blocked CD29-mediated cell-cell adhesion, implying that ROS may play a critical role in up-regulating cell-cell adhesion. Therefore, our data suggest that the activation of CD29 may be critically involved in regulating monocytic cell-mediated cell-cell adhesion and ROS generation.

• Journal of Integrative Natural Science
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• v.9 no.3
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• pp.171-176
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• 2016

Rap1 is a key regulator of cell adhesion and migration. Although increasing evidence indicates that the Rap1 signaling pathway is involved in the process of bone remodeling, the mechanism by which Rap1 regulates osteoblastic differentiation and cell adhesion remains unknown. Here, we investigated the morphological characteristics and osteoblastic differentiation of cells expressing constitutively activated form of Rap1A (Rap1ACA) or Rap1 GTPase activating protein Rap1GAP and found that activated Rap1 induces osteoblastic differentiation and cell adhesion as well as cell spreading. When osteoblastic differentiation was induced, Rap1ACA cells showed considerably higher levels of calcium deposits than the wild-type and Rap1GAP-overexpressing cells did. Rap1ACA cells showed increased spreading and size, as well as strong cell adhesion and significantly decreased growth rates. F-actin staining using phalloidin revealed several thin thread-like filopodia around the protrusions in Rap1ACA cells, which possibly contribute to the increased cell adhesion.