• Proceedings of the Korean Society of Toxicology Conference
• /
• 2003.10b
• /
• pp.120-120
• /
• 2003

Synthesis and distribution of extracellular matrix (ECM) components are dynamically altered in response to the pathophysiological processes including infection, inflammation and apoptosis. In particular, the levels of hyaluronan (HA) change with concomitant increases in the levels of collagen (e.g. type I collagen) and fibronectin in chronic liver diseases.(omitted)

• Animal cells and systems
• /
• v.8 no.1
• /
• pp.27-32
• /
• 2004

Endothellial cells are subjected to hemodynamic shear stress, the dragging force generated by blood flow. Shear stress regulates endothelial cell shape, structure, and function, including gene expression. Since endothelial cells must be anchored to their extracellular matrices(ECM) for their survival and growth, we hypothesized that ECMs are crucial for shear-dependent activation of extracellular signalactivated regulated kinase(ERK) that is important for cell proliferation. Shear stress-dependent activation of ERK was observed in cells plated on two different matrices, fibronectin and vitronectin(the two most physiologically relevant ECM in endothelial cells). We then treated bovine aortic endothelial cells(BAECs) with Arg-Gly-Asp(RGD) peptides that block the functional activation of integrin binding to fibronectin and vitronectin, and a nonfunctional peptide as a control. Treatment of cells with the RGD peptides, but not the control peptide, significantly inhibited ERK activity in a concentration-dependent manner. This supports the idea that integrin adhesion to the ligands, fibronectin and vitronectin, mediates shear stress-dependent activation of ERK. Subsequently, whereas antagonists of vitronectin(LM 609, an antibody for integrin ${\alpha}_{\gamma}$/${\beta}_3$ and XT 199, an antagonist specific for integrin ${\alpha}_{\gamma}$/${\beta}_3$) did not have any effect on shear-dependent activation of ERK, antagonists of fibronectin(a neutralizing antibody for integrin ${\alpha}_5$/${\beta}_1$or ${\alpha}_4$${\beta}_1$ and SM256) had an inhibitory effect. These results clearly demonstrate that mechanoactivation of ERK requires anchoring of endothelial cells to fibronectin through integrins.

• Proceedings of the Korean Society of Sericultural Science Conference
• /
• 2003.10a
• /
• pp.145-146
• /
• 2003

Overproduction of transforming growth factor (TGF)-$\beta$l has been implicated in the pathogenesis of fibrotic diseases. TGF-$\beta$l plays a crucial role in the accumulation of extracellular matrix (ECM) in human and experimental glomerular diseases. However, it remains unclear whether inhibition of TGF- $\beta$l overproduction would suppress TGF- $\beta$l induced ECM accumulation. To inhibit the overproduction of TGF- $\beta$l in experimental glomerulonephritis induced by anti-Thy 1.1 antibody, we introduced antisense oligodeoxynucleotides (ODN) fur TGF- $\beta$l into the nephritic kidney by the HVJ-liposome-mediated gene transfer method. (omitted)

• Journal of Animal Reproduction and Biotechnology
• /
• v.35 no.2
• /
• pp.113-118
• /
• 2020

Hepatic stellate cells (HSCs) play essential roles in normal and pathophysiological function in liver. In steady state, HSCs contribute to retinoid storage, immune tolerance, and extracellular matrix (ECM) homeostasis. Upon liver injury, they become activated and lead to morphological and functional changes. Studies have demonstrated that activation of HSCs by various stimuli such as toxins, microbial infection, or metabolic overload can promote the fibrotic changes in liver by production of ECM. Herein, we provide current knowledge about the basic characteristics of HSCs and the mechanism by which they are activated.

• Journal of the Society of Cosmetic Scientists of Korea
• /
• v.28 no.1
• /
• pp.31-41
• /
• 2002

The production of matrix matalloproteinases(MMPs) by the UV irradiated skin fibroblast and the degradation of extracellular matrix(ECM) by these enzymes is known as one of the main reasons of photoaging. Recently, Fisher group showed that the MMP expression is mainly regulated by the mitogen-activated protein(MAP) kinas family, such as extracellular signal-regulated kinase(ERK), c-Jun amino-terminal kinase(JNK) and p38, each of which forms a signaling pathway. In this work we first examined the effect of nitric oxide (NO) on the production of MMP-1 and MMP-2 by the human dermal fibroblasts (HDFs). NO is a multifunctional messenger molecule generated from L-arginine and involved in many kinds of signaling pathway. We found that the treatment of HDF with NO donor, sodium nitroprusside (SNP) enhanced the expression of MMPs with or without UV irradiation and the treatment with nitric oxide synthase (NOS) inhibitors resulted in the significant decrease of MMPs production. From these results, we concluded that the production of MMPs by the UV irradiated HDF is regulated through the signaling pathway involving NO and cyclic GMP.

• 한국생물공학회:학술대회논문집
• /
• 2000.11a
• /
• pp.429-432
• /
• 2000

Chitosan scaffold is widely applied to drug delivery and tissue engineering. We have developed chitosan scaffolds, with various pore size, by differing freezing temperature and duration of ultraviolet (UV) irradiation, for reconstructing skin equivalent. Chitosan scaffold was coated with type I collagen, fibronectin and basic fibroblast growth factor (bFGF) in various combinations and concentrations, to evaluate the effect of extracellular matrix (ECM) and bFGF on cell adhesion, growth and differentiation of dermal fibroblasts. Human dermal fibroblasts, isolated from newborn foreskin and passaged between 3 and 5, were seeded on the top of scaffolds and cultivated for 2 weeks. We examined the morphology and the secretion of ECM of fibroblasts using scanning electron microsopy (SEM) and histochemistry. A stellate morphology of fibroblasts were seen in all groups. The scaffold coated with either type I collagen and bFGF or type I collagen and fibronectin, however, showed the best condtion of dermal fibroblasts, in that the highest cell number and ECM secretion were seen. On the contrary, scaffolds coated with all three factors, type I collagen, bFGF and fibronectin, showed lower number of cells and ECM secretion than scaffolds with two factors. There was a tendency of dose-dependence in all three factors for fibroblast growth and ECM secretion. In conclusion, we may suggest that chitosan scaffold coated with either type I collagen/bFGF or type I collagen/fibronectin could provide more favorable environment for the growth and differentiation of dermal fibroblasts.

• BMB Reports
• /
• v.53 no.2
• /
• pp.74-81
• /
• 2020

Under physiological and pathological conditions, mechanical forces generated from cells themselves or transmitted from extracellular matrix (ECM) through focal adhesions (FAs) and adherens junctions (AJs) are known to play a significant role in regulating various cell behaviors. Substantial progresses have been made in the field of mechanobiology towards novel methods to understand how cells are able to sense and adapt to these mechanical forces over the years. To address these issues, this review will discuss recent advancements of traction force microscopy (TFM), intracellular force microscopy (IFM), and monolayer stress microscopy (MSM) to measure multiple aspects of cellular forces exerted by cells at cell-ECM and cell-cell junctional intracellular interfaces. We will also highlight how these methods can elucidate the roles of mechanical forces at interfaces of cell-cell/cell-ECM in regulating various cellular functions.

• Journal of Microbiology and Biotechnology
• /
• v.11 no.6
• /
• pp.922-927
• /
• 2001

In an effort to regulate the mammalian cell behavior in entrapment with a gel, we have functionalized hydrogels with the putative cell-binding (-Arg-Gly-Asp-)(RGD) domain. An adhesion molecule of Gly-Arg-Gly-Asp-Ser (GRGDS) peptides, a cell recognition ligand, was induced into thermo-reversible hydrogels, composed of N-isopropylacrylamide with small amounts of acrylic acid (typically 2-5 $mol\%$ in feed), as a biomimetic extracellular matrix (ECM). The GRGDS containing a p(NiPAAm-co-AAc) copolymer gel was studied in vitro for its ability to promote the spreading and viability of cells by introducing a GRGDS sequence. Hydrogel with no adhesion molecule was a poor ECM for adhesion, permiting spreading of only $3\%$ of the seeded cells for 36h. By immobilizing the peptide linkage into the hydrogel, the conjugation of RGD promoted $50\%$ of proliferation for 36h. However, the GREDS sequence, nonadhesive peptide linkage, conjugated hydrogel showed only $5\%$ of the seeded cell for the same time period. In addition, with the serum-free medium, only GRGDS peptides conjugated to hydrogel was able to promotecell spreading, while there was no cell proliferation in the hydrogel without GRGDS. Thus, the GRGDS peptide-conjugated thermo-reversible hydrogel specifically mediated the cell spreading. This result suggests that utilization of peptide sequences conjugating with the cell-adhesive motifs can enhance the degree of cell surface interaction and influence the long-term formation of ECM in vitro.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.30 no.2
• /
• pp.307-313
• /
• 2001

Iron excess is known to affect long-term iron accumulation and tissue change such as fibrosis in liver. To determine the changes of expression level of genes associated with fibrosis by short-term iron exposure, we measured liver mRNA levels by reverse transcription polymerase chain reaction (RT-PCR) in rats fed dietary carbonyl iron (3%, wt/wt) for 9 weeks. The results showed that the expression of the collagen (I, III) and transforming growth factor (TGF)-$\beta$I mRNAs was enhanced in high-dose iron treated rat, compared to normal-dose iron treated rat. An electron microscopy study revealed that excess iron caused increase of collagen fibrils in liver. The cell shapes and compositions of hepatocytes and extracellular matrix(ECM) in liver were changed by the iron-treatment. Also, necrosised hepatocytes were broadly seen in ECM. Taken together, we suggest that iron overload affects changes of collagen and TGF-$\beta$I gene expression and these changes are associated with liver fibrogenesis.

• Journal of Plant Biology
• /
• v.36 no.4
• /
• pp.391-398
• /
• 1993

It has been inferred that membrane-ECM (extracellular matrix) interaction in plants may be also mediated by an RGD-dependent recognition system as in animal cells. Effects of RGD peptide on ethylene production was examined in suspension cultured carrot cells. Treatment of the cells with RGD peptide containing RGD (Arg-Gly-Asp) sequence stimulated ethylene production. When RGD peptide was applied to carrot cells treated with 1M, the effect of RGD peptide appeared to be additive. ACC synthase activity in cells pretreated with RGD peptide likewise increased over the control. In an effort to check the sequence specificity of the RGD peptide, cells were treated with substituted RGD peptide, i.e. RGK (Arg-Gly-Lys) and RGE (Arg-Gly-Glu) peptide, respectively. RGK peptide did not stimulate ethylene production but RGE peptide did. The results strongly suggest that the stimulatory effect of RGD peptides on ethylene production may be associated with a physiological phenomenon through a specific recognition between RGD peptide including RGD sequence and their putative plasma membrane receptors.eptors.