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H Koide

Publications and source records attributed to H Koide.

At least 19 recordsLinked to original sources
PubMed1995

Inhibition of Ras/Raf interaction by anti-oncogenic mutants of neurofibromin, the neurofibromatosis type 1 (NF1) gene product, in cell-free systems.

The neurofibromatosis type 1 (NF1) gene encodes a protein, neurofibromin, containing GTPase-activating protein-related domain (GRD) that stimulates intrinsic GTPase activity of Ras protein. By screening a randomly mutagenized NF1-GRD library in Saccharomyces cerevisiae, we isolated two NF1-GRD mutants (NF201 and NF204) with single amino acid substitutions, which suppress the heat shock-sensitive phenotype of the RAS2(G19V) mutant. The NF1-GRD mutants also suppress the oncogenic Ras-induced transformation of NIH 3T3 mouse fibroblasts (Nakafuku, M., Nagamine, M., Ohtoshi, A., Tanaka, K., Toh-e, A., and Kaziro, Y. (1993) Proc. Natl. Acad. Sci. U.S.A. 90, 6706-6710). In this paper, we investigated the molecular mechanism of inhibition of the transforming Ras-specific function by the NF1-GRD mutants in mammalian cells. In human embryonic kidney (HEK) 293 cells, the mutant NF1-GRDs attenuated the stimulation of mitogen-activated protein kinase by Ras(G12V), but not by platelet-derived growth factor. In cell-free systems, purified recombinant NF1-GRD mutants showed an inhibitory effect on the association of Ras.guanosine 5'-O-(3-thiotriphosphate) (GTP gamma S) with Raf at several times lower concentrations than the wild type. Furthermore, it was revealed that the binding affinity of the mutant NF1-GRDs toward Ras.GTP gamma S is approximately 5-10 times higher than the wild type. These results suggest that the mutant NF1-GRDs tightly bind to an oncogenic Ras in its GTP-bound active conformation and block the interaction between Ras and its effector, Raf.

3T3 Cells↗
PubMed1995

Analysis of enterovirus genotypes using single-strand conformation polymorphisms of polymerase chain reaction products.

Enterovirus genotypes were identified rapidly by reverse (RT-PCR) followed by single-strand conformation polymorphism (SSCP) analysis. The primer pair was chosen from the highly conserved sequence at the 5' non-coding region of enterovirus genomes. RT-PCR amplified a 154 bp sequence in all samples from 14 serotypes of enteroviruses, including group A and B Coxsackie viruses, echoviruses and polioviruses. SSCP analysis of these products revealed different electrophoretic profiles. Thus, SSCP analysis will be useful for differentiating the genotypes of enteroviruses, and may be applicable for rapid diagnosis of enteroviral infection.

Base Sequence↗
PubMed1995

Effect of a specific endothelin A receptor antagonist on murine lupus nephritis.

The present study was designed to assess whether a specific endothelin A (ETA) receptor antagonist, FR139317, affects the progression of lupus nephritis and affects transcription of mRNA for extracellular matrix (ECM) components, metalloproteinases (MMPs) and tissue inhibitor of metalloproteinase (TIMP)-1, and accumulation of ECM proteins in the renal cortex of NZB/W F1 mice. mRNA levels for alpha 1(I), alpha 1(III), alpha 1(IV) collagen chains, laminin B1 and B2 chains, heparan sulfate proteoglycan (HSPG), MMP-1, -2, -3, and TIMP-1 increased significantly as nephritis progressed in NZB/W F1 mice. At 48 weeks of age, the levels of mRNA for alpha 1(I), alpha 1(III), alpha 1(IV) collagen chains, laminin B1 and B2 chains, HSPG, MMP-1, -2, -3, and TIMP-1 were increased by 5.6- (P < 0.001), 3.6- (P < 0.01), 6.8- (P < 0.001), 5.2- (P < 0.001), 5.0- (P < 0.001), 6.0- (P < 0.001), 7.6- (P < 0.001), 4.2- (P < 0.01), 8.2- (P < 0.001), and 15.2-fold (P < 0.001), respectively, in the renal cortex of NZB/W F1 mice compared to NZW mice. Immunofluorescence microscopy showed that the accumulation of collagens I, III, and IV, laminin, and HSPG in the renal cortex of NZB/W F1 mice increased markedly with the progression of nephritis. At 20 weeks of age, NZB/W F1 and NZW mice were divided into two groups that received either FR139317 or its vehicle (saline) intraperitoneally, daily, for 28 weeks. The development of histological lesions, proteinuria, hypertension, accumulation of collagens I, III, and IV, laminin, and HSPG in the renal cortex of NZB/W F1 mice were suppressed by FR139317 treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Effects of a low-protein diet on glomerular endothelin family gene expression in experimental focal glomerular sclerosis.

1. The present study was designed to assess whether glomerular expression of mRNAs for endothelin-1 and endothelin-3, as well as endothelin receptors A and B is affected by a low-protein diet during the course of focal glomerular sclerosis. 2. Focal glomerular sclerosis was induced in rats by injection of puromycin aminonucleoside on days 0, 27, 34 and 41 in conjunction with unilateral nephrectomy on day 22. Control rats were subjected to nephrectomy or sham operation on day 22. 3. Animals were divided into six groups. In group 1, the puromycin aminonucleoside-injected rats were fed a standard diet containing 22% protein. In group 2, the puromycin aminonucleoside-injected rats were fed a low-protein diet containing 6% protein, which was initiated on the day of the first puromycin aminonucleoside injection. In group 3, the nephrectomized rats without puromycin aminonucleoside were fed a standard diet. In group 4, the nephrectomized rats without puromycin aminonucleoside were fed a low-protein diet. In group 5, the sham-operated rats were fed a standard diet. In group 6, the sham-operated rats were fed a low-protein diet. 4. The percentage of sclerotic glomeruli in group 1 rats increased markedly with time, reaching 77% on day 80. 5. The glomerular mRNA levels for endothelin-1 and endothelin receptors A and B increased significantly as glomerular sclerosis progressed, whereas no endothelin-3 mRNA was detected in the glomeruli of any group. The endothelin-1 production in isolated glomeruli from group 1 increased significantly as glomerular sclerosis progressed.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Glomerular expression of smooth-muscle myosin heavy-chain isoforms in aminonucleoside nephrosis in rats.

1. We investigated the glomerular expression of three types of myosin heavy-chain isoforms, including S-myosin heavy-chain 40 (SM1), S-myosin heavy-chain 29 (SM2) and FS-myosin heavy-chain 34 (SMemb) in puromycin aminonucleoside nephrosis. 2. There was little change in SM1 and SM2 mRNA levels throughout the experiment. In contrast, glomerular SMemb mRNA increased on days 2 and 4 (before and soon after the onset of proteinuria, respectively), but declined on day 8 (the peak of proteinuria). 3. Histological myosin heavy-chain expression was examined using three antibodies against SM1, SM2 and SMemb. Immunohistochemically, SM1 and SM2 were absent in the glomeruli associated with puromycin aminonucleoside nephrosis until day 20. The SMemb isoform was barely detectable in normal glomeruli, but substantial amounts of SMemb were demonstrated in the glomeruli of rats with puromycin aminonucleoside nephrosis. In the puromycin aminonucleoside-treated rats, the number of SMemb-positive glomerular cells increased on days 2 and 4. 4. We examined whether levels of alpha-smooth-muscle actin or proliferating cell nuclear antigen correlated with myosin heavy-chain levels in the glomeruli of rats with puromycin aminonucleoside nephrosis. None of the cellular components in the glomeruli was positive for either alpha-smooth-muscle actin or proliferating cell nuclear antigen in puromycin aminonucleoside nephrosis. 5. Administration of methylprednisolone to puromycin aminonucleoside-treated rats resulted in the rapid disappearance of proteinuria. However, methylprednisolone did not affect SMemb mRNA or immunostaining in a glomeruli of rats with puromycin aminonucleoside nephrosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Binding capacity of serum IgA to jacalin in patients with IgA nephropathy using jacalin-coated microplates.

Binding capacity of serum IgA to jacalin in 22 patients with IgA nephropathy, 14 patients with diffuse mesangial proliferative glomerulonephritis (non-IgA nephropathy) and 20 age-matched healthy adults was examined by enzyme-linked immunoassay (ELISA) using jacalin-coated microplates. In contrast to previous findings, the binding capacity of serum IgA to jacalin in patients with IgA nephropathy measured by ELISA using jacalin-coated microplates was significantly higher than that in healthy adults. The ratio of serum IgA levels measured by this method to those obtained by single radial immunodiffusion was significantly increased in patients with IgA nephropathy. It appeared that the capacity of serum IgA binding to jacalin was marked in these patients. It is concluded that the binding capacity of serum IgA to jacalin is not ubiquitously impaired in all patients with IgA nephropathy.

Adult↗
PubMed1995

Enalapril attenuates increased gene expression of extracellular matrix components in diabetic rats.

This study was designed to assess whether the glomerular expression of mRNA for extracellular matrix (ECM) components including alpha 1 (I), alpha 1 (III), and alpha 1 (IV) collagen chains, laminin B1 and B2 chains, metalloproteinases (MMP), and tissue inhibitor of metalloproteinases (TIMP) is affected by enalapril in 12- and 24-wk-old rat after streptozotocin injection. Animals were divided into three groups; untreated diabetic rats, enalapril-treated diabetic rats, and control rats. Enalapril treatment was continued for 24 wk. Enalapril reduced both creatinine clearance (P < 0.01) and urinary protein excretion (P < 0.01) in diabetic rats. In diabetic rats, mRNA levels for alpha 1 (IV) collagen chain, laminin B1 and B2 chains, and alpha 1(I) and alpha 1(III) collagen chains increased significantly at 24 wk compared with those in controls [alpha 1(IV): 3.8-fold (P < 0.01); laminin B1: 6.2-fold (P < 0.01); laminin B2:5.4-fold (P < 0.01), alpha 1(i): 4.8-fold (P < 0.01) and alpha 1(III): 3.8-fold (P < 0.01)]. At 24 wk, mRNA levels for MMP-1 and MMP-3 fell to 40% (P < 0.01) and 20% (P < 0.01), respectively, in the glomeruli of diabetic rats compared with levels in controls. In contrast, mRNA levels for TIMP-1 and TIMP-2 increased significantly at 24 wk after streptozotocin injection (TIMP-1: 8.0-fold (P < 0.01) and TIMP-2: 6.4-fold (P < 0.01)).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Modulation of glomerular endothelin and endothelin receptor gene expression in aminonucleoside-induced nephrosis.

This study assessed glomerular endothelin (ET)-1, ET-3, and ET-receptor A and B mRNA levels in puromycin aminonucleoside (PAN)-induced nephrosis. During the nephrotic stage, 8 days after PAN injection, ET-1 and ETB receptor mRNA were elevated by 2.8 +/- 0.8-fold (P < 0.01) and 2.4 +/- 0.9-fold (P < 0.01), respectively, as compared with controls. These mRNA levels decreased to control levels by Day 20, when the nephrosis was in remission. In contrast, glomerular ETA receptor mRNA levels did not change in PAN nephrosis or control rats during the experimental period. ET-3 mRNA was not detected in the glomeruli of PAN nephrosis or control rats. Additionally, plasma ET concentration and glomerular ET production were measured in PAN nephrosis and control rats by radio-immunoassay. Eight days after PAN injection, ET-1 levels in plasma and glomeruli were not significantly altered in rats with PAN-induced nephrosis (glomeruli, 104.68 +/- 16.46 pg/mg of protein versus 98.24 +/- 13.68 pg/mg of protein; plasma, 2.68 +/- 1.10 versus 2.52 +/- 0.98 pg/mL). The administration of methylprednisolone to PAN rats resulted in the rapid disappearance of proteinuria and partially attenuated the increased ET-1 and ETB receptor gene expression in the glomeruli. These data indicate that glomerular ET-1 and ETB receptor expression in PAN nephrosis in increased at the mRNA level and that methylprednisolone treatment results in an attenuated increase.

Animals↗
PubMed1995

Effect of a specific endothelin receptor A antagonist on mRNA levels for extracellular matrix components and growth factors in diabetic glomeruli.

We have previously reported that the mRNA levels of extracellular matrix (ECM) components including alpha 1(I), alpha 1(III), and alpha 1(IV) collagen chains, laminin B1 and B2 chains, and growth factors including tumor necrosis factor (TNF)-alpha, platelet-derived growth factor (PDGF)-B chain, transforming growth factor (TGF)-beta, and basic fibroblast growth factor (FGF) all increase with age in diabetic glomeruli. The present study was designed to assess whether glomerular expression of these mRNAs in rat diabetic glomeruli is affected by a specific endothelin receptor A antagonist, FR139317. Diabetes was produced by streptozotocin injection, and animals were divided into four groups: untreated diabetic rats, FR139317-treated diabetic rats, control nondiabetic rats, and FR139317-treated control rats. FR139317 treatment was continued for 24 weeks. FR139317 attenuated the rise in creatinine clearance (P < 0.01) and reduced urinary protein excretion (P < 0.01) in diabetic rats, but did not affect blood pressure. FR139317 attenuated the increases in glomerular mRNA levels of alpha 1(I) (P < 0.01), alpha 1(III) (P < 0.01), and alpha 1(IV) (P < 0.01) collagen chains, laminin B1 (P < 0.01) and B2 (P < 0.01) chains, TNF-alpha (P < 0.01), PDGF-B (P < 0.01), TGF-beta (P < 0.001) and basic FGF (P < 0.01) in diabetic rats. However, FR139317 did not affect these mRNA levels in glomeruli of control rats. These findings suggest that FR139317 may be useful in the treatment of diabetic glomerulopathy by reducing mRNA levels of ECM components and growth factors.

Aging↗
PubMed1994

Detection of glycosylated protein in renal tissues and dermal vascular vessels in the microalbuminuric stage of diabetic nephropathy using the nitro blue tetrazolium reaction.

Detection of glycosylated protein in renal and dermal tissues was performed in patients in the microalbuminuric stage of diabetic nephropathy using the nitro blue tetrazolium (NBT) reaction. The intensity of NBT staining in glomeruli and dermal vascular vessels was marked in the microalbuminuric stage as well as in the overtly proteinuric stage. The NBT staining in the renal and dermal vascular walls in both stages was significantly stronger than in the samples of control autopsy patients. It appeared that nonenzymatic glycosylation in various tissues, i.e. kidneys and dermal vascular vessels, had already progressed in the microalbuminuric stage in patients with diabetic nephropathy.

Adult↗
PubMed1993

Detection of activated platelets in urinary sediments by immunofluorescence using monoclonal antibody to human platelet GMP-140 in patients with IgA nephropathy.

The presence of activated platelets in the urinary sediments was studied by indirect immunofluorescence using monoclonal antigranular membrane protein (GMP)-140 antibody. GMP-140 is generally expressed on the activated-platelets and -vascular endothelial cells. The purpose of the present study was to determine if the presence of activated platelets in the urinary sediments is correlated with glomerular injuries in patients with IgA nephropathy. Fourteen patients with IgA nephropathy and 11 patients with diffuse mesangial proliferative glomerulonephritis without glomerular IgA deposition (PGN) were examined. The number of activated platelets in the urinary sediments was markedly increased in patients in the advanced stage of IgA nephropathy. The ratio of activated platelets to total platelets in the urinary sediments was also increased in such patients. It appears that the detection of activated platelets in the urinary sediments is useful in determining the degree of histological changes in IgA nephropathy.

Adult↗
PubMed1992

Recognition of an antiparallel beta-sheet structure of human epidermal growth factor by its receptor. Site-directed mutagenesis studies of Ala-30 and Asn-32.

The Ala-30 and Asn-32 residues involved in the major antiparallel beta-sheet structure of human epidermal growth factor (hEGF) were substituted with various amino acid residues, and the receptor-binding affinities of the nine variant hEGFs were determined by the use of human KB cells. The Ala-30----Arg, Ala-30----His and Ala-30----Phe substitutions drastically reduced the binding affinity, suggesting that the side chain in position 30 of Ala-30 of hEGF is required to be small for the receptor binding. The Asn-32----Asp substitution significantly reduced the binding affinity, while the Asn-32----His variant could bind to the receptor as well as to the wild-type hEGF. Therefore, it seems to be important for receptor binding that the side chain in position 32 does not have a negative charge but does have an NH group. Thus, we propose that, in the ligand-receptor complex, the receptor recognizes, on one side of the antiparallel beta-sheet structure of hEGF, a wider contact area than previously suggested.

Alanine↗
PubMed1992

A site-directed mutagenesis study on the role of isoleucine-23 of human epidermal growth factor in the receptor binding.

The isoleucine-23 residue of human epidermal growth factor (hEGF) was substituted by a variety of amino acid residues and the receptor-binding activities of variant hEGFs were determined by the use of human KB cell. Tight receptor binding was found of variants with hydrophobic amino acid residues in position 23. The size of the isoleucine residue was nearly optimum for the receptor binding as compared with other hydrophobic residues. The structure analysis by two-dimensional nuclear magnetic resonance spectroscopy showed that the substitution at position 23 only slightly affected the tertiary structure of hEGF. These indicate that the side chain of isoleucine residue in position 23, which is exposed on the protein surface, directly binds to a hydrophobic pocket of the receptor.

Amino Acid Sequence↗
PubMed1992

Isolation and characterization of delta-subspecies of protein kinase C from rat brain.

The delta-subspecies of protein kinase C (delta PKC) was purified to near homogeneity from the Triton X-100 extract of the rat brain particulate fraction by successive chromatographies on S-Sepharose fast flow, phenyl 5PW, heparin 5PW, hydroxyapatite, and Mono Q columns. The purified enzyme was a doublet with molecular masses of 78 and 76 kDa on SDS/PAGE. The doublet proteins were separated partially by Mono Q column chromatography; both were recognized by the antibodies raised against synthetic oligopeptides, parts of the deduced amino acid sequence of the rat delta PKC. Protein phosphatase 2A treatment suggested that the 78-kDa protein was a phosphorylated form of the 76-kDa protein. To confirm the structural and genetic identity of the doublet proteins, delta PKC was expressed in COS 7 cells by transfecting its cDNA-constructed plasmid and was purified for comparison. This recombinant enzyme was also a doublet. The enzymes isolated from the brain and COS 7 cells showed identical reactivities with delta PKC-specific antibodies, chromatographic behaviors, and V8 protease peptide mappings. In addition, these two enzyme preparations were indistinguishable from each other in their responses to phosphatidylserine, diacylglycerol, phorbol esters, free fatty acids, Ca2+, and enzyme inhibitors. Comparison was also made between the enzymologic properties of delta PKC and alpha PKC, which were distinctly different from each other.

Animals↗
PubMed1992

Isolation and characterization of the epsilon subspecies of protein kinase C from rat brain.

The epsilon subspecies of protein kinase C (epsilon PKC) was purified to near homogeneity from the soluble fraction of rat brain by successive chromatographies on DEAE-cellulose, threonine-Sepharose, phenyl-5PW, Mono Q, heparin-5PW, and hydroxyapatite columns. The enzyme from COS-7 cells that were transfected with an epsilon PKC cDNA expression plasmid showed the same elution profile. The purified enzyme from the brain was a double (96 and 93 kDa) on SDS/PAGE. Both the doublet proteins were recognized by antibodies raised against several oligopeptides that were parts of the deduced amino acid sequence of the rat brain epsilon PKC. When treated with potato acid phosphatase, both doublet proteins disappeared with the concomitant appearance of a single protein at 90 kDa, suggesting that epsilon PKC exists in the tissue as phosphorylated forms. The physiological significance of this phosphorylation is unknown. The enzymes from the rat brain and COS-7 cells were indistinguishable from each other in their kinetic and catalytic properties. Unlike alpha-, beta I-, beta II-, and gamma PKC, epsilon PKC was independent of Ca2+ but absolutely required phosphatidylserine and diacylglycerol for its activation; a tumor-promoting phorbol ester could replace diacylglycerol. epsilon PKC showed enzymological properties similar to those of delta PKC, except that epsilon PKC but not delta PKC was greatly activated by free arachidonic acid. Immunoblot analysis revealed that, in marked contrast to delta PKC, epsilon PKC is expressed predominantly in the brain tissue and only in trace amounts in heart, lung, spleen, thymus, and testis.

Alkaloids↗
PubMed1992

Characterization of protein kinase C in Xenopus oocytes.

Protein kinase C (PKC) was partially purified from Xenopus laevis oocytes by ammonium sulfate fractionation followed by DEAE-cellulose and hydroxyapatite column chromatography. In the latter chromatography, two distinct PKC activities were identified. Both PKC fractions contained an 80 kDa protein which was recognized by three antisera raised against the conserved regions of mammalian PKC. However, specific antisera against alpha, beta I, beta II, and gamma-subspecies of rat PKC did not recognize the protein. Kinetic properties of the Xenopus PKCs were very similar to those of the rat alpha PKC, and only a subtle difference was found in the mode of activation by arachidonic acid. When oocytes were treated with the tumor promoter, phorbol 12-myristate 13-acetate, one of the Xenopus PKCs was found to disappear very rapidly, while the other remained unchanged up to 2 hr.

Animals↗