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F Shimizu

Publications and source records attributed to F Shimizu.

At least 19 recordsLinked to original sources
PubMed2006

Transcription factor Ets-1 is essential for mesangial matrix remodeling.

Most advanced glomerular diseases are characterized by abnormal extracellular matrix (ECM) accumulation in the glomeruli, and matrix metalloproteinases (MMPs) play a pivotal role in ECM remodeling in various glomerular diseases. The proto-oncogene, ets-1, is a transcription factor regulating the expression of various matrix proteinases, including MMP-1, MMP-3, and MMP-9. The goal of the present study was to characterize the role of Ets-1 in the progression of glomerular diseases. Overexpression of Ets-1 in cultured mesangial cells prevented transforming growth factor (TGF)-beta-induced inhibition of DNA-binding activity and TGF-beta-induced type I collagen production. In addition, exogenous Ets-1 abolished TGF-beta-induced collagen gel contraction. The in vivo transfection of the ets-1 gene into nephritic kidney resulted in the increases in glomerular MMP-1, MMP-3, and MMP-9 mRNA, decreases in mesangial ECM deposition, and attenuation of fibronectin extradomain A (EDA) and type I collagen expression. In contrast, knockdown of Ets-1 in glomeruli resulted in severe ECM deposition in diseased glomeruli. In conclusion, Ets-1 promotes degradation of ECM proteins and is critical for integral glomerular reorganization.

Animals↗
PubMed2006

Microarray analysis of a reversible model and an irreversible model of anti-Thy-1 nephritis.

A single intravenous injection of anti-Thy-1 monoclonal antibody (mAb) 1-22-3 is known to cause reversible mesangial proliferative glomerulonephritis. However, mAb 1-22-3 injection followed by unilateral nephrectomy leads to progressive glomerulosclerosis and tubulointerstitial change with an irreversible course. To identify genes that play an important role in the irreversible progression of renal injury, we used microarray technology to identify differences in gene expression between these models. Rats were intravenously injected with mAb 1-22-3 1 week after unilateral nephrectomy (irreversible model) or a sham operation (reversible model), and rats were killed on days 4, 7, 14, 42, and 56 after the injection. complementary DNA probes prepared from kidney messenger RNAs were hybridized with oligonucleotide microarrays containing 4854 rat genes. The microarray identified 189 differentially expressed genes, having at least a two-fold difference in expression level between the two models, and they were classified into five clusters. One of the clusters consisted of genes whose expression was markedly upregulated in the irreversible model. This cluster included the genes encoding osteopontin, kidney injury molecule-1, and thymosin beta10. Increased expression of thymosin beta10 was localized mainly in macrophages in the fibrotic interstitium, and upregulation of thymosin beta10 expression was also observed in a unilateral ureteral obstruction model. The microarray analysis yielded information on the molecular mechanisms responsible for the difference in disease progression between the reversible and irreversible model of anti-Thy-1 nephritis. Thymosin beta10 may play an important role in the progression of kidney disease.

Animals↗
PubMed2006

Blockade of VEGF accelerates proteinuria, via decrease in nephrin expression in rat crescentic glomerulonephritis.

Vascular endothelial growth factor (VEGF) is a potent angiogenic factor that maintains the glomerular and peritubular capillary (PTC) network in the kidney. The soluble form of the VEGF receptor-1 (soluble fms-like tyrosine kinase 1 (sFlt-1)) is known to regulate VEGF activity by binding VEGF in the circulation. We hypothesized that VEGF may be beneficial for maintaining glomerular filtration barrier and vascular network in rats with progressive glomerulonephritis (GN). For blockade of VEGF activity in vivo, rats were transfected twice with plasmid DNA encoding the murine sFlt-1 gene into femoral muscle 3 days before and 2 weeks after the induction of antiglomerular basement membrane antibody-induced GN. Inhibition of VEGF with sFlt-1 resulted in massive urinary protein excretion, concomitantly with downregulated expression of nephrin in nephritic rats. Further, blockade of VEGF induced mild proteinuria in normal rats. Administration of sFlt-1 affected neither the infiltration of macrophages nor crescentic formation. In contrast, treatment of sFlt-1 accelerated the progression of glomerulosclerosis and interstitial fibrosis accompanied with renal dysfunction and PTC loss at day 56. VEGF may play a role in maintaining the podocyte function as well as renal vasculature, thereby protecting glomeruli and interstitium from progressive renal insults.

Animals↗
PubMed2005

Exploring RNA interference as a therapeutic strategy for renal disease.

The short synthetic interfering RNA duplexes (siRNAs) can selectively suppress gene expression in somatic mammalian cells without nonselective toxic effects of double-stranded RNA (dsRNA). However, a selective in vivo delivery of siRNA transfer has not been reported in kidney. Here, we investigated whether injection of synthetic siRNAs via renal artery followed by electroporation could be effective and therapeutic in silencing specific gene in glomerulus. We investigated the effect of siRNA in rat cultured mesangial cells (MCs) and showed that siRNA sequence-specific suppression of transgene expression was over a 1000-fold more potent than that by antisense oligodeoxynucleotide (ASODN). Transfection of siRNA targeting luciferase into rat kidneys significantly inhibited expression of a cotransfected luciferase expression vector in vivo. The delivery of siRNA targeting enhanced green fluorescent protein (EGFP) in the transgenic 'green' rat reduced endogenous EGFP expression, mainly in glomerular MCs. Furthermore, RNAi targeting against TGF-beta1 significantly suppressed TGF-beta1 mRNA and protein expression, thereby ameliorated the progression of matrix expansion in experimental glomerulonephritis. In addition, vector-based RNAi also inhibited TGF-beta1 expression in vitro and in vivo. In conclusion, siRNA-directed TGF-beta1 silencing may be of therapeutic value in the prevention and treatment of fibrotic diseases.

Animals↗
PubMed2004

Supernumerary auricle on the lateral canthus.

A boy was born with an appendage on his right lateral canthus, with associated supernumerary auricles on the right cheek and a right ocular dermoid. We resected the appendage. Its core was composed of elastic cartilage, as is the external auricle. The lateral canthus overlaps facial cleft line No. 8 in Tessier's classification [Plast Reconstr Surg 4 (1976) 69] and forms the upper part of the first branchial arch. It appears that our patient's appendage was a supernumerary auricle, which had developed from the first branchial arch.

Choristoma↗
PubMed2001

Specular reflection of very slow metastable neon atoms from a solid surface.

An ultracold narrow atomic beam of metastable neon in the 1s3[(2s)(5)3p:1P0] state is used to study specular reflection of atoms from a solid surface at extremely slow incident velocity. The reflectivity on a silicon (1,0,0) surface and a BK7 glass surface is measured at the normal incident velocity between 1 mm/s and 3 cm/s. The reflectivity above 30% is observed at about 1 mm/s. The observed velocity dependence is explained semiquantitatively by the quantum reflection that is caused by the attractive Casimir-van der Waals potential of the atom-surface interaction.

Journal Article↗
PubMed2001

Sequence of events in the glomerular capillary wall at the onset of proteinuria in passive Heymann nephritis.

Proteinuria in passive Heymann nephritis (PHN) results from complement-mediated glomerular injury, since complement depletion with cobra venom factor (CVF) prevents proteinuria. However, there are no comprehensive morphological studies identifying the sites of injury leading to onset of proteinuria. To address this issue, we attempted to locate sites of injury involved in the onset of proteinuria in PHN. PHN was induced in intact Munich-Wistar rats (PHN-rats, examined at days 3, 5, and 7) and in complement-depleted rats (CVF treated, PHN-CVF-rats, examined at days 3 and 5). The distribution of endogenous albumin in the glomerular basement membrane (GBM) was studied in in situ drip-fixed glomeruli using immunogold immunocytochemistry, and glomerular anionic sites were visualized by polyethyleneimine staining. In addition, the ultrastructural localization of an epitope recognized by a proteinuria-inducing monoclonal antibody (called 5-1-6) directed against the slit diaphragm was examined. Significant proteinuria was seen in intact PHN-rats, starting at day 5. The intensity of gold labeling for endogenous albumin was significantly increased at the outermost site of the GBM (GBM interfacing foot process and the filtration slit, designated area O) at day 3 in both PHN-rats and PHN-CVF-rats in comparison to untreated controls. At day 5, labeling for albumin in area O was decreased in PHN-rats, but not in PHN-CVF-rats, where it was then higher; in PHN-rats, some areas between epithelial cells and subepithelial deposits were almost free of albumin labeling at day 7. There was no evidence of epithelial cell detachment in any group at day 5, but on day 7 limited focal detachment was seen exclusively in PHN-rats. In proteinuric rats, amorphous material that stained for albumin could be seen in the urinary space, without any exocytosis of labeling by glomerular epithelial cells. A significant reduction of intensity of staining for anionic sites was seen in parallel in both groups, but only in the regions of the lamina rara externa adjacent to subepithelial deposits. This local loss of charge might contribute to enhanced permeability to albumin in both PHN- and PHN-CVF-rats. Changes in the appearance of the filtration slits and in the density and distribution of antigen recognised by monoclonal antibody 5-1-6 were similar in PHN- and PHN-CVF-rats at day 5. Complement depletion prevented neither the reduction in anionic sites of the GBM nor the changes in the slit diaphragm observed. These data suggest that albumin leakage between the epithelial cell and the GBM (area O) could occur in PHN-rats, perhaps as a result of epithelial foot-process changes. This may be the final link in the chain of events responsible for the onset of proteinuria in PHN.

Albumins↗
PubMed2001

Glomerular CD8+ cells predict progression of childhood IgA nephropathy.

The aim of this study was to evaluate whether the infiltrating T-lymphocyte can be a predictor in the disease progression of IgA nephropathy (IgAN). Twenty children with IgAN, followed for more than 5 years, were divided into progressive (n=5) and non-progressive groups (n=15). We assessed glomerular and interstitial infiltration of T-lymphocytes (CD4+ and CD8+ cells) and expression of alpha-smooth muscle actin (alpha-SMA) and transforming growth factor-beta (TGF-beta) using an indirect immunofluorescence method on the renal biopsies. We analyzed their relationship to the degree of proteinuria, histological changes, and prognosis. The number of CD8+ cells in glomeruli and in interstitium was higher in the progressive group than in the non-progressive group. The glomerular alpha-SMA staining was more intensive in the progressive group than in the non-progressive group. Urinary protein and the degree of histological changes were also higher in the progressive group than in the non-progressive group. Among these markers, the number of glomerular CD8+ cells was the most apparent difference between the two groups. In conclusion, these results indicate that the number of glomerular CD8+ cells is the most sensitive predictor of disease progression in childhood IgAN.

Actins↗
PubMed2001

Podocyte injuries exacerbate mesangial proliferative glomerulonephritis.

BACKGROUND: From the observations of morphology seen in early phases of the experimental models of the irreversible mesangial proliferative glomerulonephritis, we hypothesized that podocyte injury is one of the important factors in bringing upon irreversible glomerular alterations. To verify this hypothesis, we investigated whether podocyte injury induced by puromycin aminonucleoside (PAN) injection affects the mesangial alterations of anti-Thy 1.1 glomerulonephritis. METHODS: Female Wistar rats were injected with 0.5 mg monoclonal antibody (mAb) 1-22-3 five days after the injection of 10 mg or 5 mg/100 g body weight (BW) of puromycin aminonucleoside (PAN), and sacrificed at 7 days or 8 weeks after the mAb 1-22-3 injection. RESULTS: Consecutive injections of 10 mg/100 g BW of PAN and mAb 1-22-3 caused the irreversible mesangial alteration with persistent proteinuria (at week 8, proteinuria 100.3 +/- 57.8 mg/24 h, matrix score 1.13 +/- 0.52, collagen type I score 2.04 +/- 0.53, mRNA for collagen type I 227 +/- 79% to the group with a single injection of 1-22-3). Although single injection of 5 mg/100 g BW of PAN was not capable of inducing abnormal proteinuria, consecutive injections of 5 mg/100 g BW of PAN and mAb 1-22-3 also caused irreversible mesangial alteration and persistent proteinuria. CONCLUSIONS: Podocyte injury might be an important factor that exacerbates mesangial proliferation and mesangial matrix expansion. The irreversible mesangial alterations caused by consecutive injections of PAN and mAb 1-22-3 may be a novel model that could be used to analyze the mechanism of progressive mesangial alteration.

Animals↗
PubMed2001

Isotretinoin alleviates renal damage in rat chronic glomerulonephritis.

BACKGROUND: Retinoids, derivatives of vitamin A, have strong anti-inflammatory and antiproliferative properties. We previously demonstrated that the pan-agonists all-transretinoic acid (RA) and isotretinoin (13-cis RA) alleviate renal damage in rat acute glomerulonephritis (GN) induced by anti-Thy-1.1 mAb OX-7. METHODS: The present study examined the effects of low dose and high dose treatment with isotretinoin in the chronic glomerulonephritis model, Thy-GN. Thy-GN was induced by a single intravenous injection of monoclonal antibody (mAb) 1-22-3 in uninephrectomized Wistar rats (N = 7 to 10 per group). Control and nephritic groups were treated with vehicle (veh), low dose isotretinoin (2 mg/kg body wt), or high dose isotretinoin (10 mg/kg body wt). The experiment was terminated 60 days after induction of Thy-GN. RESULTS: In animals with Thy-GN, isotretinoin abrogated the increase in blood pressure and significantly reduced albuminuria. Glomerulosclerosis index, glomerular and interstitial cell counts, as well as the area of the interstitial space were significantly lower in nephritic rats treated with low and high dose isotretinoin compared to vehicle-treated nephritic controls. Treatment with isotretinoin also significantly reduced the number of glomerular and interstitial macrophages. The increase of transforming growth factor (TGF)-beta1, TGF receptor II and prepro-endothelin-1 gene expression in vehicle-treated nephritic rats was significantly attenuated by isotretinoin. CONCLUSIONS: Treatment with isotretinoin significantly reduces glomerular and interstitial damage in rats with chronic glomerulonephritis as indicated by different functional and histological markers. Retinoids may provide a novel therapeutic option for the treatment of glomerulonephritis.

Albuminuria↗
PubMed2001

Effects of anti-TGF-beta type II receptor antibody on experimental glomerulonephritis.

BACKGROUND: Renal fibrosis, characterized by the accumulation of extracellular matrix (ECM), is a common histopathological feature of progressive renal disease of diverse etiology. Interaction between transforming growth factor-beta (TGF-beta) and TGF-beta type II receptor (TGF-betaIIR) may play an important role in the ongoing fibrotic process. TGF-betaIIR and TGF-beta have been reported to be up-regulated in human glomerulopathies. In order to block the TGF-beta system, many studies have inhibited TGF-beta itself, but not its receptors. Our study explored the effects of fully human monoclonal antibody against TGF-betaIIR (hTGF-betaIIRAb) on experimental proliferative glomerulonephritis. METHODS: hTGF-betaIIRAb was generated from Xenomice. The expression of TGF-betaIIR was studied by immunohistochemistry in normal and anti-Thy-1 nephritis rats. hTGF-betaIIRAb or control Ab was injected intraperitoneally at day 0 and day 4 of anti-Thy-1 nephritis, and rats were sacrificed at day 7. Effects of hTGF-betaIIRAb were assessed by histological and immunopathological measurements. RESULTS: The specificity of hTGF-betaIIRAb was confirmed by ELISA and Western blot analysis. By immunostaining, TGF-betaIIR expression was up-regulated in the proliferative lesions of anti-Thy-1 nephritis at day 7. In the hTGF-betaIIRAb-treated group, the extent of mesangial expansion was less than that in the control group. By immunohistology, alpha-smooth muscle actin, fibronectin-EDA, and type I collagen were significantly reduced in the hTGF-betaIIRAb-treated group. CONCLUSIONS: Anti-TGF-betaIIR antibody ameliorated ECM accumulation in anti-Thy-1 nephritis. Our data suggest that TGF-betaIIR may be one of the therapeutic targets, and that fully human monoclonal antibody against TGF-betaIIR may have a new therapeutic potential for renal fibrosis.

Actins↗
PubMed2001

Caveolae in mesangial cells and caveolin expression in mesangial proliferative glomerulonephritis.

BACKGROUND: Caveolae are plasma membrane invaginations that have a diameter of 40 to 60 nm. Recent evidences have demonstrated that caveolae contain a variety of signal transduction molecules. Caveolin is a marker protein of caveolae and has been proposed to play a negative regulatory role in signal transduction. The aim of this study was to investigate the behavior of caveolae and caveolin in experimental glomerulonephritis, the localization of both platelet-derived growth factor (PDGF) and transforming growth factor-beta (TGF-beta) receptors in the caveolae membrane, and the regulation of caveolin expression in cultured mesangial cells. METHODS: The expression of caveolin-1 was examined by immunoblotting and immunohistology using anti-caveolin antibody in anti-Thy-1 nephritis. The caveolae membrane fraction of mesangial cells was isolated by sucrose gradient method and expression of PDGF receptor and TGF-beta receptor were detected by immunoblotting. The effects of mitogens such as phorbol 12-myristate 13-acetate (PMA) and PDGF on the expression of caveolin-1 protein and mRNA were also examined in cultured mesangial cells. RESULTS: Caveolin-1 was mainly expressed in glomeruli and was significantly up-regulated in anti-Thy-1 nephritis rat kidney. In cultured mesangial cells, the membrane invaginations of caveolae were revealed by electron microscopy. PDGF receptors abounded in the caveolae membrane and rapidly changed their subcellular distribution after ligand stimulation. In contrast, TGF-beta receptors abounded in the non-caveolae membrane and did not change after ligand stimulation. Decreases in caveolin-1 protein, which were associated with increases in mRNA expression after the exposure of PMA or PDGF-BB, suggested an increased turnover of caveolin-1 in mesangial cells stimulated by mitogens. CONCLUSION: To our knowledge, this electron microscopical study is the first to demonstrate the presence of caveolae in cultured mesangial cells. Caveolae integrate PDGF receptors, and caveolin-1 may play a role in the pathogenesis of the mesangial proliferative glomerular diseases through PDGF signaling.

Animals↗
PubMed2001

FAT is a component of glomerular slit diaphragms.

BACKGROUND: Slit diaphragms are intercellular junctions of podocytes of the renal glomerulus. The molecular composition of slit diaphragms is still elusive. Slit diaphragms are characterized by the presence of a wide intercellular space. The morphological feature is shared by desmosomes and adherens junctions, which contain members of the cadherin superfamily. Thus, we have hypothesized that some components of slit diaphragms belong to the cadherin superfamily. Consequently, we have isolated cDNA encoding FAT from reverse-transcribed (RT) glomerular cDNA by homology polymerase chain reaction (PCR) using primers based on conserved sequences in cadherin molecules. FAT is a novel member of the cadherin superfamily with 34 tandem cadherin-like extracellular repeats, and it closely resembles the Drosophila tumor suppressor fat. METHODS: Expression of FAT was examined in glomeruli of the adult rat kidney by the ribonuclease protection assay and in situ hybridization. To localize the FAT protein in podocytes minutely, we prepared affinity-purified antibody against FAT by immunizing rabbits against an oligopeptide corresponding to the C-terminal 20 amino acids. RESULTS: Expression of FAT mRNA was detected in total RNA from glomeruli. In situ hybridization revealed significant signals in podocytes. Western blot analysis using solubilized glomeruli showed a single band, in which the molecular weight was more than 500 kD. Immunostaining of cultured epithelial cells from rat kidney (NRK52E) revealed FAT accumulation in cell-cell contact sites. In the glomerulus, FAT staining was observed distinctly along glomerular capillary walls. Double-label immunostaining using monoclonal antibody against slit diaphragms (mAb 5-1-6) showed identical localization of anti-FAT antibody and mAb 5-1-6. Furthermore, the double-label immunogold technique with ultrathin cryosections demonstrated that gold particles for FAT cytoplasmic domain were located at the base of slit diaphragms labeled by mAb 5-1-6 and that the cytoplasmic domain of FAT colocalized with ZO-1, a cytoplasmic component associated with slit diaphragms. CONCLUSION: The molecular structure of FAT and its colocalization with 5-1-6 antigen and ZO-1 indicate that FAT is a component of slit diaphragms.

Animals↗
PubMed2001

Crescent-forming mechanism in an irreversible Thy-1 model in rats.

BACKGROUND: The crescent-forming mechanism has not yet been fully clarified and a cell which constitutes a crescent still remains controversial. This study was undertaken to analyze the crescent-forming mechanism in an irreversible Thy-1 model by applying a new marker-recognizing monoclonal antibody (mAb) OS-3. METHODS: An irreversible Thy-1 model was induced by an intravenous injection of 500 microg of anti-Thy-1 mAb 1-22-3 to unilaterally nephrectomized Wistar rats. Seven rats were sacrificed 3, 7 and 14 days after the mAb injection respectively and the renal tissues were examined histologically and immunohistochemically. RESULTS: Inflammatory cells were demonstrated mostly in the interstitium, but they were located within advanced cellular crescents in later stages. OS-3, which stained parietal glomerular epithelial cell (PGEC) only partly in a normal rat kidney section, reacted to PGEC more extensively at day 3 and also with cellular crescents at day 7. During the course of this model the podocytes lost their characteristic to be stained by anti-podocalyxcin Ab and obtained a new marker of a diseased state, i.e. to be positively stained by OS-3. CONCLUSION: Glomerular epithelial cells, but not inflammatory cells, are suggested to directly participate in the crescent formation in early stages, and podocytes with phenotypic changes might be partly involved in the formation of the crescents.

Animals↗
PubMed2000

Interferometric modulation of an atomic beam by an electric field: A phase hologram for atoms

Electric-field-controlled atomic holography has been demonstrated. A binary hologram pattern was encoded in the gaps of regularly spaced parallel stripes of platinum electrodes formed on SiN4 thin film. Each electrode was either grounded or connected to a terminal. The electrode connections were arranged so that an electric field appeared in approximately half the 512 gaps when a finite voltage was applied to the terminal. By controlling this voltage, we could shift, erase, or switch holographically reconstructed two-dimensional images of atoms on a screen.

Journal Article↗
PubMed2000

Analysis of cytokine production in the colon of nude mice with experimental colitis induced by adoptive transfer of immunocompetent cells from mice infected with a murine retrovirus.

LP-BM5 murine leukemia virus (MuLV) is known to induce murine AIDS (MAIDS). We have shown that Sjögren's syndrome (SjS)-like exocrinopathy can be induced in mice with MAIDS and that adoptive transfer of spleen cells from MAIDS mice can induce inflammatory bowel disease-like colitis as well as SjS-like exocrinopathy in nude mice. To assess the role of interferon (IFN)-gamma and interleukin (IL)-10 in the pathogenesis of our experimental model, we tried to identify the cells producing these cytokines and their localization in the colitis lesions in situ. Expression of mRNA for IFN-gamma and IL-10 was assessed by RT-PCR, and protein expression of these cytokines was also analyzed in frozen sections of colon by double-color-staining immunofluorescence (IF). An increase of IFN-gamma and IL-10 mRNA was detected in the colon of mice with colitis, but not in that of control mice. Double-color IF showed that Mac-1(+) cells were positive for IFN-gamma or IL-10 and that most CD4(+) T cells were positive for IL-10, although the population of IFN-gamma-positive CD4(+) T cells was low. In our experimental colitis model, Mac-1(+) macrophages that produce both IFN-gamma and IL-10 might play a crucial role in the pathogenesis of colitis in combination with CD4(+) T cells.

Adoptive Transfer↗
PubMed2000

Localization of Smad6 and Smad7 in the rat kidney and their regulated expression in the anti-Thy-1 nephritis.

Under normal conditions, kidney expresses Smad6 and Smad7 most abundantly among the organs of the body. To understand the physiological roles of these Smad expressions in the kidney, we first identified the sites of Smad6 and Smad7 expression in the rat kidney by in situ hybridization. The expression of Smad7 in the rat kidney was only observed in the glomeruli, while Smad6 was expressed in both the glomeruli and thick ascending limb of Henle's loop. In order to investigate whether Smad6 and 7 are also involved in the negative feedback loop of TGF-beta signaling in vivo, we examined the changes of mRNA levels of these Smads in the glomeruli of rat anti-Thy1 (1-22-3) nephritis, a model where the expression of TGF-beta in the glomeruli has been shown to be most up-regulated from day 4 to 14 after the antibody injection. Unexpectedly, 7 days after injection, the levels of Smad6 and Smad7 did not increase but rather decreased to approximately 70% of the levels on day 0. During that period, Smad7 immunostaining was observed in the glomerular endothelial cells (GEN) where Smad3 immunostaining was also observed. This suggested that Smad7 expression was not augmented by the TGF-beta signal in GEN in vivo in anti-Thy-1 nephritis. The absence of up-regulation of these inhibitory Smads may be involved in the pathogenesis of anti-Thy-1 nephritis.

Animals↗