Journal of Yeungnam Medical Science

Ho Sun Park

4 Articles

The Effects of Hantaan Virus on the Expression of Platelet Activating Factor Receptor and on the Activity of Platelet Activating Factor Acetylhydrolase.: Ji Young Hwang, Jong Won Park, Sae Yong Hong, Ho Sun Park; Yeungnam Univ J Med. 2008;25(1):41-49. Published online June 30, 2008; DOI: https://doi.org/10.12701/yujm.2008.25.1.41

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Abstract PDF: BACKGROUND
The central physiological derangement of hemorrhagic fever with renal syndrome (HFRS) caused by hantaan virus (HTNV) is a vascular dysfunction, manifested by hemorrhage, impaired vascular tone and increased vascular permeability. Platelet activating factor (PAF), whose actions are mediated through a specific receptor, is a potent bioactive lipid. PAF has diverse biological functions in the vascular system, such as increasing vascular permeability, adhesion of leukocytes to the endothelium and reduction of cardiac output, which result in hypotension and shock. The goal of the present study was to investigate whether PAF is involved in the pathogenesis of HFRS. For this purpose, we evaluated the effect of HTNV on the expression of PAF receptor (PAF-R) and on the activity of PAF-acetylhydrolase (PAF-AH) instead of PAF because PAF is rapidly degraded by PAF-AH in vivo. MATERIALS AND METHODS: To evaluate the expression of PAF-R, we performed reverse-transcription PCR, western blot and FACS analyses using HTNV-infected human umbilical vein endothelial cells (HUVECs) and non-infected (control) HUVECs. In addition, we measured the activity of plasma PAF-AH in HFRS patients and normal healthy persons. RESULTS: The mRNA and protein expression of PAF-R was increased in HTNV-infected HUVECs compared with control HUVECs at 2 and 3 days post-infection (d.p.i.). FACS analysis showed that HTNV induced the surface expression of PAF-R in HUVECs from 2 d.p.i. The activity of plasma PAF-AH was 2.5-fold lower in HFRS patients than in normal healthy persons. CONCLUSION: Increased PAF-R expression by HTNV might increase the responsiveness to PAF in endothelial cells. Reduced PAF-AH activity in the blood of HFRS patients might delay PAF degradation. These results suggest that changes in PAF-R and PAF-AH by HTNV might influence to PAF activity and might be involved in the vascular dysfunction of HFRS.

Effect of Leptin on the Expression of Chemokine Genes in THP-1 Cells.: Jin Hee Choi, Ho Sun Park, Tae Yoon Lee, Sung Kwang Kim, Hee Sun Kim; Yeungnam Univ J Med. 2003;20(2):129-141. Published online December 31, 2003; DOI: https://doi.org/10.12701/yujm.2003.20.2.129

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Abstract PDF: BACKGROUND
Leptin is a 16-KDa non-glycosylated peptide hormone synthesized almost exclusively by adipocytes. The well-known function of leptin is regulation of food intake and energy expenditure. Leptin also plays a regulatory role in immune and inflammatory process including cytokine production. The purpose of this study was to investigate the effect of leptin on the expression of several chemokine genes(RANTES, IL-8, MCP-1, IP-10, Mig, MIP-1alpha, MIP-1beta, and GRO-alpha) in THP-1 cells. MATERIALS AND METHODS: Total RNA of THP-1 cells were prepared by Trizol method, and then stimulated with the leptin(250 ng/microliter) or LPS(100 ng/microliter). We examined the expression patterns of various chemokine mRNAs in THP-1 cell lines by RT-PCR and Northern blot. RESULTS: Leptin did not induce the expression of chemokine mRNAs in THP-1 cells. The expression patterns of RANTES, IL-8, MCP-1, IP-10, and Mig mRNAs in THP-1 cells stimulated with leptin and LPS simultaneously was almost same to the patterns of LPS alone-induced chemokine mRNAs. RANTES mRNA expression was independent on the concentrations of leptin. Although leptin did not have strong effect on the expression of RANTES, IL-8, MCP-1, IP-10, Mig, MIP-1alpha, MIP-1beta, and GRO-alpha mRNAs in THP-1 cells, leptin could induce the expression of long isoform of leptin receptor(OB-RL) mRNA, and its expression was elevated in simultaneous stimulation of leptin and LPS. CONCLUSION: These data suggest that leptin is able to induce OB-RL in THP-1 cells, however, leptin has little effect on the expression of pro-inflammatory chemokine genes.

In Vitro Culture of Human Nasal Epithelial Cells by Monolayer Culture of Dissociated Cells.: Yong Dae Kim, Si Youn Song, Myung Ki Min, Jang Su Suh, Kei Won Song, Ho Sun Park; Yeungnam Univ J Med. 1998;15(2):286-296. Published online December 31, 1998; DOI: https://doi.org/10.12701/yujm.1998.15.2.286

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Abstract PDF: Different techniques for culturing respiratory epithelial cells have been developed to overcome the limitations of studies on in vivo and on bioptic material. Traditionally, culture systems are divided into organ cultures, explant cultures and dissociated cell cultures. The first two contain both epithelial and non-epithelial cells. However, in monolayer cultures of dissociated cells only epithelial cells are present, the effects observed are caused by a pure epithelial responses. The purpose of this study is to establish primary culture method of human nasal epithelium (HNEC) by monolayer culture of dissociated cells to evaluate the role of the epithelial cells in the allergic and non-allergic nasal inflammatory reactions. HNEC was prepared by primary culture method of monolayer culture of dissociated cells from human inferior nasal turbinate mucosa of septal deviation patients. Primary cultured cells were characterized by indirect immunofluorescence assay and transmission electron microscopy. The immunoreactivities of cytokeratin-pan and cytokeratin No. 8 were observed in cultured HNEC. However, the immnoreactivities of vimentin and von Willebrand factor were not observed in cultured HNEC. The tonofilaments and desmosome were observed in cultured HNEC. The cultured epithelial cells were identified to be pure nasal epithelial cells. The monolayer culture of dissociated cells could successfully be employed for further study to investigate the role of the epithelial cells in allergic or non-allergic nasal inflammatory diseases.

The Supressive Effects of Integrin Antibodies on the Infection of Hantaan Virus in Fibroblasts.: Ho Sun Park, Ki Duk Kim, Sung Kwang Kim; Yeungnam Univ J Med. 1998;15(1):55-66. Published online June 30, 1998; DOI: https://doi.org/10.12701/yujm.1998.15.1.55

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Abstract PDF: 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.

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