• The Korean Journal of Zoology
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• v.38 no.1
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• pp.78-86
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• 1995

Our previous report has suggested that the decrease of fibronectin level during mvogenesis is due to the decreased Bvailabilitv of receptor (matrix assembly receptor) for 29-kDa fragment of fibronectin. In the present study, we demonstrate that G protein and adenvlate cvclase system are involved in the regulation of fibronectin matrix assembly and that when fibronectin level in extracellular matrix decreases, the postmitotic fusion-capable cells emerge more frequently from the proliferative population. This proposal is based on the following observations. (1) Cholers toxin, which increases intracellular CAMP, caused a decrease in the ability of mvoblasts to incorporate fibronectin into extracellular matrix. (2) Cholera toxin decreased the proliferation of mvoblasts and Induced the precocious fusion. (3) decAMP, which was found to induce the precocious fusion and decrease the proliferation of myoblasts, decreased the fibronectin level in extracellular matrix and matrix assembly receptor for fibronectin- (4) RGOS, whlh inhibits the incorporation of fibronectin into extracellular matrix, induced the precocious fusion and reduced the proliferaton of mvoblasts. These results suggest that CAMP regulates the fibronectin levels in extracellular matrix and that the alteration of fibronectin level is involved in regulation of the proliferation and differentiation of chick embryonic mvoblasts.

• Molecules and Cells
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• v.22 no.3
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• pp.308-313
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• 2006

Stromal cell-derived factor (SDF-1) is a CXC chemokine that selectively activates the CXCR4 chemokine receptor. Fibronectin is an intracellular matrix component that binds integrin and mediates cell-matrix adhesion. Activation of the integrin receptor can occur in two ways: by ligand binding (outside-in signaling), and in response to intracellular events (inside-out signaling). In the current study we showed that SDF-$1{\alpha}$ inhibited adhesion of T lymphocyte Jurkat cells resulting from binding high concentrations of fibronectin as well as that of THP-1 monocytes. The effect of SDF-$1{\alpha}$ on fibronectin-mediated adhesion was partly reversed by the CXCR4 receptor antagonist T140. Our results suggest that an SDF-1/CXCR4 signal pathway modulates fibronectin-mediated lymphocytes adhesion.

• The Korean Journal of Zoology
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• v.33 no.1
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• pp.108-118
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• 1990

Fibronectin is a glycoprotein found in the extracellular matrix as well as in the serum, and has been known to exert pronouned effed on the myoblast fusion. Our previous studies have suggested that the decrease of fibronectin levels during myogenesis is due to the decreased availability of the receptor for the 28 kDa fragrnent of fibronetin. In the fusion-blocked myoblasts by EGTA, the levels of fibronetin and binding of 28 kDa fragment decreased but far less than the control level. In contrast, the levels of fibronetin and binding of 28 kDa fragment decreased to the control level in the myoblast released from the fusion block. On this account, we suggest that the decrease of fibronetin levels during myoblast fusion is closely associated with the loss or alteration of the receptor for 28 kDa fragment. Mild trypsin treatment decreased the binding of the 28 kDa fragment to the myoblasts significandy. Similarly, the presence of gangliosides in the binding media decreased the binding of the 28 kDa fragment in a dose-dependent manner. Furthermore, gel overlay of 125 I-28 kDa fragment on the SDS-PAGE of the myoblast homogenates revealed that the 28 kDa fragment bound to a 43 kDa protein and to gangliosides as well. These results suggest that myoblast fusion is correlated with decrease of the receptor for the 28 kDa fragment and that the receptor might be a glycoprotein that contains glyco-conjugate found in gangliosides.

• The Korean Journal of Physiology and Pharmacology
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• v.1 no.1
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• pp.55-63
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• 1997

The present study was designed to quantify the alterations of renal renin, angiotensin type I receptor ($AT_1$), $TGF-{\beta}1$, and fibronectin gene expression in rats with unilateral ureteral obstruction (UUO). We also investigated the change of $AT_1$ density during UUO. Reverse transcription-polymerase chain reaction (RT-PCR) technique and receptor binding assay were used to detect mRNA expression and receptor density, respectively. At one day after UUO, renin mRNA level of the obstructed kidneys was decreased transiently and then subsequently increased to the level of sham kidneys. In the contralateral kidneys of the same rats, on the contrary, renin mRNA level was gradually decreased. Then, at 9 days after UUO, it was significantly lower than that of sham kidneys. The expressions of both $AT_1$ subtypes, called $AT_{1A}$ and $AT_{1B}$, mRNAs did not change at any time. UUO led to a significant decrease in $AT_1$ density in the obstructed kidneys compared with the sham kidneys at 1 and 3 days $(66\;{\pm}\;11.6%\;(p<0.005)\;and\;73\;{\pm}\;4.0%$ (p<0.01), respectively). Thereafter, $AT_1$ density was gradually increased and at 9 days it showed a marked elevation in the obstructed kidneys compared to the sham kidneys. In contrast, in the contralateral kidneys $AT_1$ density was significantly reduced from 3 to 9 days after UUO. The $TGF-{\beta}$1 mRNA level of the obstructed kidneys was unexpectedly decreased at 6 days after UUO. Then, at 9 days it was followed by a significant increase in the obstructed kidneys, whereas it showed an obvious decrease in the contralateral kidneys. In addition, fibronectin mRNA level was also significantly increased in the obstructed kidneys after UUO compared to the sham or the contralateral kidneys of the same rats. These results suggest a differential regulation of renal renin, $AT_1$ receptor, $TGF-{\beta}$1 and fibronectin mRNA levels at different stages of UUO.

• The Korean Journal of Zoology
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• v.37 no.4
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• pp.592-596
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• 1994

The interaction between fibronectin (FN) and its receptors controls cell attachment and migration, two crucial events during monocyte development and differentiation. To investigate the functional role of FN and its receptor, we have studied adhesion of monocyte to two different regions of FN (38- and 85-kDa domain), as well as the expression of the integrin during monocle differentiation. Anti-integrin Rl subunit antibody completely blocked the attachment of FN-coated latex beads to macrophage, but the effect of anti-integrin u4 antibody was much less significant. Rat monocyte expressed integrin $u4\beta1$ predominantly, while macrophage expressed $\alpha5\beta1$ as analyzed tv flow cvtometer and western blot. From these results, it can be suggested that these two integrins plan different roles during monocyte differentiation.

• Archives of Pharmacal Research
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• v.25 no.1
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• pp.71-76
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• 2002

Ginseng has been used as a traditional medicine with various therapeutic effects. However, it is still unknown which component of this plant is effective at promoting wound healing. Recently, ginsenoside $Rb_2$ has been reported to improve wound healing. In this study, to investigate the reported wound healing effect of the ginsenoside $Rb_2$, cell morphology and protein factors involved in epidermal formation were evaluated by immunshemical and immunoblotting analysis. $Rb_2$ stimulated epidermal cell proliferation, and the cell showed a 1.5-fold increase in thymidine uptake compared to the control (p<0.05, n=3). Futheremore $Rb_2$, was found to stimulate epidermis formation in a dose-dependent manner in raft culture, and to dose dependently enhance the expressions of protein factors related to cell proliferation, namely, epidermal growth factor and its receptor, fibronectin and its receptor, keratin 5/14, and collagenase 1 (p<0.05, n=3~9). It is believed that ginsenoside $Rb_2$, enhances epidermal cell proliferation by upregulating the expressions of these proliferation-related factors.

• Journal of Periodontal and Implant Science
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• v.25 no.3
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• pp.518-528
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• 1995

The immunohistochemical study has been performed on the distribution of receptors for various growth factors in the newly forming granulation tissues following the guided tissue regeneration procedures. Two specimens from 2 different patients were collected from the newly forming granulation tissues at 2 weeks following GTR procedures using Gore-tex menbrane and rubber dam, respectively. For immunohistochemical localization of each recptor, anti-platelet-derived growth factor $receptor-{\alpha}$, anti-platelet-derived growth factor $receptor-{\beta}$. anti-insulin-like growth factor receptor, anti-basic fibroblast growth factor receptor, anti-transforming growth $factor-{\beta}$ receptor and anti-fibronectin receptor were incubated onto the specimens as primary antibodies. After the reaction, FITC-conjugated second antibodies have been applied. When the total numbers of immunoreactive cells and the true positive cells were counted, there were high variability among receptors tested in the present study. The mean number of immunoreactive cells were highest in the case for anti-IFG-1 receptor. However the number of true positive cells were highest in the case for $TGF-{\beta}$ receptor. The present investigation indicated that the receptor for $TGF-{\beta}$ were stongly expressed in the newly forming granulation tissues following the guided tissue regeneration therapy.

• YAKHAK HOEJI
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• v.52 no.2
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• pp.111-116
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• 2008

Diethylstilbestrol (DESB) is a synthetic estrogen not only that routinely prescribed, but also that known to be a teratogen. In this study, we found a novel pharmacological feature that DESB is able to positively modulate CD29 $({\beta}1-integrin)$ function. Thus, DESB up-regulated homotypic cell-cell adhesion of monocytic U937 cells mediated by CD29. However, DESB did not increase the surface level of CD29 and its binding activity to ligand (fibronectin), according to flow cytometric analysis and cell-fibronectin adhesion assay. Instead, the DESB-mediated up-regulation of cell-cell adhesion was blocked by several signaling enzyme inhibitors. Treatment of U0126 [an extracellular signal-regulated kinase (ERK) inhibitor], SB20358 (a p38 inhibitor) or Rp-8-pCPT-cGMP (a protein kinase G inhibitor) clearly inhibited DESB-mediated up-regulation of cell-cell adhesion induced by CD29. However, estrogen receptor antagonist ICI 182,780 failed to abrogate DESB effect. Therefore, our data suggest that DESB may up-regulate CD29-mediated cell-cell adhesion via modulating intracellular signaling enzymes such as ERK, PKG, and p38, independent of estrogen receptor function.

• BMB Reports
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• v.52 no.6
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• pp.373-378
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• 2019

The nucleotide-binding and oligomerization domain (NOD) is an innate pattern recognition receptor that recognizes pathogen- and damage-associated molecular patterns. The 29-kDa amino-terminal fibronectin fragment (29-kDa FN-f) is a matrix degradation product found in the synovial fluids of patients with osteoarthritis (OA). We investigated whether NOD2 was involved in 29-kDa FN-f-induced pro-catabolic gene expression in human chondrocytes. The expression of mRNA and protein was measured using quantitative real-time polymerase chain reaction (qrt-PCR) and Western blot analysis. Small interfering RNAs were used for knockdown of NOD2 and toll-like receptor 2 (TLR-2). An immunoprecipitation assay was performed to examine protein interactions. The NOD2 levels in human OA cartilage were much higher than in normal cartilage. NOD1 and NOD2 expression, as well as pro-inflammatory cytokines, including interleukin-1beta (IL-$1{\beta}$) and tumor necrosis factor-alpha (TNF-${\alpha}$), were upregulated by 29-kDa FN-f in human chondrocytes. NOD2 silencing showed that NOD2 was involved in the 29-kDa FN-f-induced expression of TLR-2. Expressions of IL-6, IL-8, matrix metalloproteinase (MMP)-1, -3, and -13 were also suppressed by TLR-2 knockdown. Furthermore, NOD2 and TLR-2 knockdown data demonstrated that both NOD2 and TLR-2 modulated the expressions of their adaptors, receptorinteracting protein 2 (RIP2) and myeloid differentiation 88, in 29-kDa FN-f-treated chondrocytes. 29-kDa FN-f enhanced the interaction of NOD2, RIP2 and transforming growth factor beta-activated kinase 1 (TAK1), an indispensable signaling intermediate in the TLR-2 signaling pathway, and activated nuclear factor-${\kappa}B$ (NF-${\kappa}B$), subsequently leading to increased expressions of pro-inflammatory cytokines and cartilage-degrading enzymes. These results demonstrate that 29-kDa FN-f modulated pro-catabolic responses via cross-regulation of NOD2 and TLR-2 signaling pathways.

• The Journal of Korean Medicine
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• v.22 no.3
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• pp.141-155
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• 2001

Objective : The aim of this study is to investigate the effect of Injin fractions on hepatic fibrosis induced by $TGF-{\beta}1$. Method : $TGF-{\beta}1$ mRNA, protein, $TGF-{\beta}1$ receptor, Smad family and PAI-I mRNA were studied in HepG2 cell, and the proliferation, connective tissue growth factor, fibronectin and collagen type I mRNA in T3891 fibroblast by quantitative RT-PCR, ELISA and thymidine incorporation assay. Results : On $TGF-{\beta}1$ mRNA and protein synthesis in HepG2, $H_2O$, butanol and hexane fractions of Injin showed inhibitory effect in a dose-dependent way. In the study on $TGF-{\beta}1$ receptor, Smad family and PAI-1 mRNA in HepG2, $H_2O$, butanol and hexane fraction of Injin showed inhibitory effect on the expression of PAI-1 in a dose-dependent way. On the proliferation of T3891 fibroblast induced by $TGF-{\beta}1$, $H_2O$, ethylacetate and butanol fractions of Injin showed inhibitory effect. In the study on the factors affected by $TGF-{\beta}1$, $H_2O$, ethylacetate and butanol fractions of Injin showed inhibitory effect on CTGF, and $H_2O$, butanol, chloroform and hexane fractions showed inhibitory effect on the expression of collagen type I, whereas no fraction showed inhibitory effect on the expression of fibronectin Conclusion : These results show that each fraction of Injin acts as a fibrosis inhibitory factor by itself or in combination, ultimately inhibiting liver cirrhosis.