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Gi Dong Han

Publications and source records attributed to Gi Dong Han.

14 recordsLinked to original sources
PubMed2006

Synaptic vesicle protein 2B is expressed in podocyte, and its expression is altered in proteinuric glomeruli.

Synaptic vesicle protein 2B (SV2B) was identified by the subtraction hybridization technique as a molecule of which mRNA expression was decreased in puromycin aminonucleoside (PAN) nephropathy by glomerular cDNA subtraction assay. The expression of SV2B was detected in glomerular lysate with Western blot analysis. Dual-labeling immunofluorescence studies with glomerular cell markers demonstrated that SV2B is expressed in glomerular visceral epithelial cells (podocytes). The expression of SV2B is detected also in cultured podocyte and in human kidney section as podocytic pattern. The decrease of SV2B mRNA was already detected before the onset of proteinuria in PAN nephropathy. The mRNA expression of SV2B clearly is altered not only in PAN nephropathy but also in another proteinuric state that is caused by an antibody against nephrin, a functional molecule of the slit diaphragm. The decreased intensity in SV2B staining was already detected before the peak of proteinuria in both models with immunofluorescence study. A reduced amount of SV2B was detected in both models also with Western blot analysis. CD2AP, another functional molecule of the slit diaphragm, was observed in cytoplasm, including the processes area of the cultured podocyte, and when the podocyte was treated with small interfering RNA for SV2B, CD2AP staining at the process area was not detected. These results suggest that SV2B is a functional molecule of podocyte, and SV2B may play a role in the expression and proper localization of CD2AP.

Adaptor Proteins, Signal Transducing↗
PubMed2006

Attenuation of mouse acute colitis by naked hepatocyte growth factor gene transfer into the liver.

BACKGROUND: Hepatocyte growth factor (HGF) has multiple biological effects on a wide variety of cells. It modulates intestinal epithelial proliferation and migration, and critically regulates intestinal wound healing. AIMS: To investigate the therapeutic effect of HGF gene transfer, we introduced the HGF gene into the liver of mice with acute colitis. METHODS: The rat HGF expression plasmid vector, pCAGGS-HGF, was injected via the tail vein into C57BL/6 mice, followed by dosing with dextran sulfate sodium in distilled water. Firstly, the HGF gene was injected once on day 0. Secondly, the HGF gene was injected on day 0 and again on day 2. RESULTS: Injection of the HGF gene ameliorated colitis with inhibition of both loss of body weight and shortening of colon length. It protected the colon from epithelial erosions and cellular infiltration. Expression of mRNAs for IFN-gamma, IL18, and TNF-alpha was reduced in the colon. In contrast, expression of mRNA for IL-10 was increased. The numbers of BrdU-positive intestinal epithelial cells were increased, and the numbers of TUNEL-positive apoptotic cells were decreased. Furthermore, a second injection prolonged the elevation of serum HGF levels, and ameliorated the symptoms better than a single injection. The empty pCAGGS plasmid did not ameliorate acute colitis. CONCLUSIONS: HGF gene transfer attenuated acute colitis by facilitating intestinal wound repair as well as inhibiting inflammation, suggesting a new strategy for treatment of IBD.

Acute Disease↗
PubMed2006

Role of podocyte slit diaphragm as a filtration barrier.

Although the role of glomerular basement membrane has been emphasised as the barrier for retaining plasma proteins in the past three decades, some recent studies have demonstrated that the slit diaphragm of the glomerular epithelial cell (podocyte) is the structure likely to be the barrier in the glomerular capillary wall. Nephrin and podocin were identified as gene products mutated in Finnish-type congenital nephrotic syndrome and autosomal recessive steroid-resistant nephrotic syndrome, respectively. Nephrin s located at the outer leaflet of plasma membranes of the slit diaphragm. Podocin is reported to have an interaction with nephrin. The anti-nephrin antibody is capable of inducing massive proteinuria, which indicates that nephrin is a key functional molecule in the slit diaphragm. The expression of nephrin and podocin was reduced in glomeruli of minimal change nephrotic syndrome, which suggested that the altered expression of these molecules contributes to the development of proteinuria also in acquired diseases. Some recent studies demonstrated that CD2-associated protein (CD2AP) is also a functional molecule in the slit diaphragm, and its expression is altered in membranous nephropathy. These observations suggested that alteration of the molecular arrangement in the slit diaphragm is involved in the development of proteinuria in several kinds of glomerular diseases.

Animals↗
PubMed2006

Role of IP-10/CXCL10 in the progression of pancreatitis-like injury in mice after murine retroviral infection.

Exocrinopathy and pancreatitis-like injury were developed in C57BL/6 (B6) mice infected with LP-BM5 murine leukemia virus, which is known to induce murine acquired immunodeficiency syndrome (MAIDS). The role of chemokines, especially CXCL10/interferon (IFN)-gamma-inducible protein 10 (IP-10), a chemokine to attract CXCR3+ T helper 1-type CD4+ T cells, has not been investigated thoroughly in the pathogenesis of pancreatitis. B6 mice were inoculated intraperitoneally with LP-BM5 and then injected every week with either an antibody against IP-10 or a control antibody. Eight weeks after infection, we analyzed the effect of IP-10 neutralization. Anti-IP-10 antibody treatment did not change the generalized lymphadenopathy and hepatosplenomegaly of mice with MAIDS. The treatment significantly reduced the number of IP-10- and CXCR3-positive cells in the mesenteric lymph nodes (mLNs) but not the phenotypes and gross numbers of cells. In contrast, IP-10 neutralization reduced the number of mononuclear cells infiltrating into the pancreas. Anti-IP-10 antibody treatment did not change the numbers of IFN-gamma+ and IL10+ cells in the mLN but significantly reduced their numbers, especially IFN-gamma+ and IL-10+ CD4+ T cells and IFN-gamma+ Mac-1+ cells, in the pancreas. IP-10 neutralization ameliorated the pancreatic lesions of mice with MAIDS probably by blocking the cellular infiltration of CD4+ T cells and IFN-gamma+ Mac-1+ cells into the pancreas at least at 8 wk after infection, suggesting that IP-10 and these cells might play a key role in the development of chronic autoimmune pancreatitis.

Animals↗
PubMed2005

IFN-inducible protein-10 plays a pivotal role in maintaining slit-diaphragm function by regulating podocyte cell-cycle balance.

IFN-inducible protein-10 (IP-10/CXCL10) is a potent chemoattractant for activated T lymphocytes and was reported recently to have several additional biologic activities. In this study, the pathophysiologic role of IP-10 in the glomerular visceral epithelial cell (podocyte) was investigated. In cultured podocytes subjected to recombinant IP-10 treatment, the expression of slit-diaphragm (SD) components nephrin and podocin clearly was heightened. Rats that had puromycin aminonucleoside nephropathy and anti-nephrin antibody-induced nephropathy and were subjected to anti-IP-10 function-blocking antibody (anti-IP-10 mAb) treatment displayed a decrease in the protein level of SD components, as well as exacerbated proteinuria. For exploration of the mechanisms of this process, the interaction between IP-10 and the cell-cycle regulatory proteins was investigated. Cultured podocytes subjected to recombinant IP-10 treatment displayed an increase in the protein level of p27(Kip1), whereas the levels of cyclins E and A decreased. The expression of IP-10 and SD components was heightened by the treatment of siRNA of cyclin A, whereas these expressions were lowered by the treatment of siRNA of p27(Kip1). Proteinuric rats subjected to anti-IP-10 mAb treatment displayed a heightened expression of cyclin A from the early phase of the disease, which indicates that the anti-IP-10 mAb treatment exacerbates podocyte injury by disturbing the cell-cycle balance. These results raise the possibility that IP-10 could become a novel therapeutic target in nephrotic syndrome and several diseases with altered cell-cycle balance.

Animals↗
PubMed2005

Altered expression of junctional adhesion molecule 4 in injured podocytes.

Recent investigations have revealed the importance of glomerular podocytes with its diaphragm as the major filtration barrier. Junctional adhesion molecule 4 (JAM4) has been identified as a protein that interacts with membrane-associated guanyl kinase inverted (MAGI)-1 and is reported to be expressed on podocytes. To elucidate the role of JAM4 on podocytes, we examined the expression of JAM4 and MAGI-1 in normal and two different proteinuric rat models: puromycin aminonucleoside (PAN) nephropathy and anti-nephrin antibody-induced (ANA) nephropathy, one model with and one without effacement of podocyte foot processes. JAM4 was detected by immunomicroscopy at the apical membrane of normal podocytes. JAM4 immunostaining was focally increased in the podocytes in PAN nephropathy but not in ANA nephropathy. In proteinuric podocytes, the expression of JAM4 was distinct from that of MAGI-1 or other slit diaphragm molecules such as nephrin and ZO-1. Close colocalization of JAM4 and ezrin was maintained in PAN nephropathy. By immunoelectron microscopy, the signals for JAM4 were detected at the free apical membrane of the podocytes with effaced foot processes. Studies with selective detergent extract revealed that the subcellular localization of JAM4 was altered in PAN nephropathy. Thus the altered expression of JAM4 appears to be associated with morphological changes in podocytes and can be a useful marker of injured podocytes. JAM4 may have a different role at the apical membrane besides the role as a junctional molecule and is likely associated with the unique structure of this epithelium.

Amino Acid Sequence↗
PubMed2005

Multi-glycoside of Tripterygium wilfordii Hook f. ameliorates proteinuria and acute mesangial injury induced by anti-Thy1.1 monoclonal antibody.

BACKGROUND/AIMS: Multi-glycoside from Tripterygium wilfordii Hook f. (GTW) is used for various immune and inflammatory diseases including renal diseases represented by mesangial proliferative glomerulonephritis (MsPGN) in China. However, there have been no fundamental studies on the operating mechanism of GTW on MsPGN. The aim of this study is to examine as the first step the effects of GTW on acute injurious process such as mesangial injury and proteinuria in an acute and reversible Thy.1.1 glomerulonephritis (Thy1.1GN) model and then to clarify the action mechanism of GTW at molecular level by examining its effects on various injurious factors in this model. METHODS: Thy1.1 GN was induced in rats by a single intravenous injection with 500 microg of anti-Thy1.1 mAb 1-22-3. Daily oral administration of GTW and vehicle as a control was started from 3 days before injection of mAb to the day of sacrifice in each experiment. Fourteen rats were randomly divided into 2 groups, GTW-treated and vehicle-treated groups, and sacrificed on day 14 in experiment 1 or on day 7 in experiment 2 after induction of Thy1.1 GN. Proteinuria was determined on days 1, 3, 5, 7, 10 and 14 in experiment 1 or on 1, 3, 5 and 7 in experiment 2. From blood and kidneys taken at sacrifice, blood biochemical parameters, mesangial morphological changes, glomerular macrophage infiltration, and glomerular mRNA expression of cytokines were examined. RESULTS: In experiment 1, proteinuria and mesangial matrix expansion were significantly attenuated by GTW treatment. In experiment 2, GTW treatment significantly ameliorated proteinuria, mesangial lesions and macrophage accumulation in glomerulus. In addition, it significantly reduced the glomerular expression of mRNA for PDGF, MCP-1 and IL-2. CONCLUSION: GTW ameliorated not only proteinuria but also mesangial alterations in Thy1.1 GN most likely by reducing expression of injurious cytokines, indicating that GTW has suppressive effects on acute inflammatory changes in glomeruli.

Acute Disease↗
PubMed2005

Alanine-scanning mutagenesis of HM-1 killer toxin and the essential residues for killing activity.

Each of the aromatic, acidic and basic amino acid residues in HM-1 were separately substituted with alanine by site-directed mutagenesis. The mutant genes were successfully expressed in HM-1 resistant Saccharomyces cerevisiae. HM-1 gene analogues corresponding to the aromatic substitutions resulted in lower production of HM-1 analogues. In the case of the acidic amino acid residue and basic amino acid residue substitutions, some analogues were produced in the same amount as and exhibited similar killing activity to that of the wild type HM-1. But the H35A HM-1 analogue had completely lost the killing activity, and D44A, K21A, K46A, R82A, R85A and R86A HM-1 showed highly decreased killing activities. These results strongly indicate the importance of histidine-35, aspartic acid-44, lysine-21, lysine-46, and C-terminal arginine residues in HM-1 for the killing activity.

Alanine↗
PubMed2005

Nephrin and podocin dissociate at the onset of proteinuria in experimental membranous nephropathy.

BACKGROUND: The slit diaphragm plays a critical role in maintaining the barrier function of the glomerular capillary wall. The pathogenic mechanism of proteinuria in membranous nephropathy remains uncertain. This study was undertaken to analyze the pathogenic role of slit diaphragm in proteinuria in experimental membranous nephropathy. METHODS: The expression and the localization of slit diaphragm-associated molecules (nephrin, podocin, and CD2AP) and other podocyte-associated molecules (podocalyxin and alpha(3) integrin) in passive and active Heymann nephritis were analyzed by immunofluorescence and Western blot analysis. The interaction of slit diaphragm-associated molecules was investigated by the dual-labeling immunofluorescence method. The mRNA expression of these molecules was also analyzed. RESULTS: Shifts in nephrin and podocin staining patterns, from linear to granular, were detected in the early stages of passive Heymann nephritis. These shifts were not parallel, and the dissociation of these molecules was detected by the dual-labeling immunofluorescence method in passive and active Heymann nephritis. Western blot analyses with sequentially solubilized materials indicated that the nephrin-rich fraction changed from being partly detergent-resistant to being predominantly detergent-soluble. This change did not occur with podocin. Nephrin excreted into urine was already detected in the early stages of passive Heymann nephritis. Decreased mRNA expression of nephrin and podocin was observed before the onset of proteinuria. By contrast, no extensive change in the expression of alpha(3) integrin was observed in this study. CONCLUSION: Nephrin is dissociated from podocin and excreted into urine in the early stages of Heymann nephritis. The reduced expression of nephrin and podocin, along with their dissociation, may contribute to the development of proteinuria in Heymann nephritis.

Adaptor Proteins, Signal Transducing↗
PubMed2004

Decreased collagen-degrading activity could be a marker of prolonged mesangial matrix expansion.

BACKGROUND: Mesangial matrix expansion is caused by the overproduction and/or the impaired proteolytic degradation of the extracellular matrix. However, the relative contribution of these changes to the development of prolonged mesangial matrix expansion is still poorly understood. We aimed to elucidate the relative role of the matrix metalloproteinase (MMP)/tissue inhibitors of metalloproteinases (TIMPs) system in the development of prolonged mesangial matrix expansion. METHODS: We prepared two rat models, showing reversible or prolonged mesangial matrix expansion, induced by a single injection or two consecutive injections of anti-Thy-1.1 monoclonal antibody 1-22-3, respectively. We analyzed the glomerular expression of type I and type IV collagens; MMP-2, -9, and -13; membrane type 1-MMP (MT1-MMP); TIMP-1; and urinary type I collagen-degrading activity in both models. RESULTS: There were no differences in glomerular mRNA levels of type I and type IV collagens between the reversible and the prolonged models. MMP-9 mRNA expression and protein level was lower in the prolonged model than in the reversible one, whereas there were no differences in mRNA levels of MMP-2, -13, MT1-MMP, or TIMP-1 between the two models. Urinary type I collagen-degrading activity in the prolonged model was lower than that in the reversible one. Furthermore, there was a significant correlation between the mesangial matrix expansion and urinary type I collagen-degrading activity. CONCLUSIONS: Impaired expression of MMP-9 may contribute to the development of prolonged mesangial matrix expansion. Analysis of urinary type I collagen-degrading activity may provide additional diagnostic information in mesangial proliferative glomerulonephritis. Mesangial matrix expansion is caused by the overproduction and/or the impaired proteolytic degradation of the extracellular matrix. However, the relative contribution of these changes to the development of prolonged mesangial matrix expansion is still poorly understood. We aimed to elucidate the relative role of the matrix metalloproteinase (MMP)/tissue inhibitors of metalloproteinases (TIMPs) system in the development of prolonged mesangial matrix expansion.

Animals↗
PubMed2004

The role of lymphocytes in the experimental progressive glomerulonephritis.

BACKGROUND: Glomerular accumulation of leukocytes, including lymphocytes, is a common feature in most types of glomerulonephritis. However, the role of lymphocytes in progressive glomerulonephritis has not been elucidated. We examined the role of lymphocytes in the development of progressive mesangial proliferative glomerulonephritis induced by two injections of monoclonal antibody 1-22-3 in rats. METHODS: To elucidate the role of lymphocytes, circulating lymphocytes were depleted using specific monoclonal antibodies to rat lymphocytes prior to the induction of progressive glomerulonephritis. The effects of lymphocyte depletion on proteinuria and glomerular alterations were assessed 7 and 56 days after the induction of progressive glomerulonephritis. RESULTS: Significant glomerular accumulation of CD4+ T cells, CD8+ T cells, and ED3+-activated macrophage were observed after the induction of glomerulonephritis. Depletion studies showed that continuous treatment with anti-CD5, anti-CD4, or anti-CD8 treatment reduced proteinuria and ameliorated the glomerular lesions on day 56. Depletion of CD4+ T cells also reduced glomerular accumulation of CD8+ T cells and ED3+-activated macrophages, and reduced glomerular expression of mRNA for interferon-gamma (INF-gamma) (63.0% in anti-CD5 and 62.3% reduction in anti-CD4). Transit lymphocyte depletion limited in early stage of progressive glomerulonephritis demonstrated that CD4+ T-cell depletion, but not anti-CD8 treatment prevented glomerular injuries 56 days after the induction of progressive glomerulonephritis. CONCLUSION: CD4+ T cells played a central role in the development of progressive glomerulonephritis, controlling recruitment and activation of CD8+ cytotoxic cells and/or macrophages.

Animals↗
PubMed2003

IFN-inducible protein-10 has a differential role in podocyte during Thy 1.1 glomerulonephritis.

IFN-inducible protein-10 (IP-10/CXCL10) is a potent chemoattractant for activated T lymphocytes and was recently reported to have several additional biologic activities. In this study, the expression and the function in normal glomeruli and in Thy1.1 glomerulonephritis (GN) were investigated. The expression of IP-10 was detected in normal rat glomeruli mainly in the podocyte. The expression of IP-10 was also detected on the cultured podocyte. The IP-10 expression was elevated at the early phase of Thy1.1 GN. The double staining immunofluorescence study clearly demonstrated that the elevated expression of IP-10 was mostly detected in the podocyte and very partly in mesangial area. A receptor for IP-10, CXCR3, showed similar expression patterns to that of IP-10. Expressions of neither of IP-10 nor of CXCR3 were detected on the inflammatory cells. For elucidating the role of IP-10, the blocking study was carried out with monoclonal anti-IP-10 antibody. The monoclonal anti-IP-10 antibody treatment decreased the expression of IP-10 and podocyte-associated proteins such as nephrin and podocin that are reported to be essential for maintaining the podocyte function (IP-10, 53.0% to control; nephrin, 43.5%; podocin, 60.4%). The findings indicated that the anti-IP-10 treatment disturbed the podocyte function. The anti-IP-10 treatment given to the rats with Thy1.1 nephritis exacerbated proteinuria, mesangiolysis, and matrix expansion. Collectively, the findings indicated that IP-10 plays a role in maintaining the podocyte function. Also, the findings suggested that anti-IP-10 treatment exacerbated the glomerular alterations in Thy1.1 GN by disturbing the podocyte function.

Animals↗
PubMed2002

Effects of heat and high-pressure treatments on antigenicity of beef extract.

The sera of bovine gamma globulin (BGG) positive beef allergic patients were used in this study in order to investigate changes in IgE-specific binding activity with regard to beef extract altered by heat or high-pressure treatment. In inhibition-ELISA, the sample treated at 60 degrees C did not show any significant changes in the antigenicity of BGG, but the sample treated at 100 degrees C showed a decrease of the antigenicity. In the case of the treatment with heating at 100 degrees C, heat-coagulation occurred in the beef extract. The resulting supernatant and precipitate of the sample by centrifugation were analyzed by immunoblotting. Only the fraction of precipitate showed a specific binding activity with the sera. Based on this result, it was speculated that the persistent antigenicity found even after the treatment at 100 degrees C in inhibition-ELISA remained principally in the heat-coagulated fraction, which indicated the importance of the method of handling the heat-coagulation in heat treatment. High-pressure treatments (200 MPa-600 MPa) of beef extract did not show any significant changes in the binding with the sera.

Allergens↗