Biomedical subjects
Publications and source records attributed to Jun Wada.
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BACKGROUND: Nitric oxide (NO) plays important roles in a variety of pathophysiological processes. It has been reported that inducible NO synthase (iNOS) is upregulated in the glomeruli of patients with glomerulonephritis, although there has been no direct evidence that NO generated by iNOS contributes to the progression of glomerulonephritis. ONO-1714, a novel cyclic amidine analog, is a selective inhibitor of iNOS. To elucidate the role of iNOS in the pathogenesis of experimental crescentic glomerulonephritis, we examined the effect of ONO-1714 given to rats with nephrotoxic serum (NTS) nephritis. METHODS: We induced NTS nephritis in Wistar-Kyoto (WKY) rats. These rats were given ONO-1714 or physiological saline intraperitoneally for 14 days using an osmotic pump after intraperitoneal injection with NTS. RESULTS: Glomerular expression of iNOS and urinary excretion of NO metabolites (nitrite/nitrate) were increased in rats after injection of NTS. As compared with the control group, ONO-1714 significantly reduced proteinuria, crescent formation, glomerular infiltration of macrophages and urinary excretion of nitrite/nitrate. CONCLUSION: The present results suggest that NO radicals generated by iNOS contribute to the progression of experimental crescentic glomerulonephritis in WKY rats. The selective iNOS inhibitor ONO-1714 may be beneficial for the treatment of crescentic glomerulonephritis.
Mammalian nephrogenesis is modulated by a number of extracellular matrix (ECM) glycoproteins, integrins and cell adhesion molecules. We demonstrated the existence of integrins alphavbeta1, alphavbeta3, alphavbeta5 and alphavbeta6 in epithelial elements of developing nephrons. Fibrillin-1 is a putative ligand for integrin alphavbeta3, and tubulointerstitial nephritis antigen (TIN-ag) is a ligand for integrins alphavbeta3 and alpha3beta1. Fibrillin-1 and TIN-ag are also differentially expressed in the developing kidney. The inclusion of antisense oligonucleotide in a mouse kidney organ culture system indicated that the alphav-related integrins and their ligands play an important role in mammalian nephrogenesis. Recently identified modulators of cell-matrix interactions, i.e. beta-galactoside-binding mammalian lectins (galectins), are involved in cell-cell and cell-matrix interactions by cross-linking glycoconjugates located on the ECM and membrane-bound glycoproteins. We identified and cloned a new member of the galectins from embryonic kidneys, and designated it galectin-9. Since high glucose alters the expression of ECM proteins and integrins, we also investigated the influence of glucose on metanephric development. The presence of 30 mM D-glucose in metanephric organ culture induced dysmorphogenesis of the kidney accompanied by decreased expression of perlecan. Furthermore, we screened the genes differentially expressed under high glucose conditions in streptozotocin-induced newborn mouse kidneys by representational difference analysis of cDNA. We identified translocase of inner mitochondrial membrane (Tim44) and renal-specific oxido-reductase (RSOR). The roles of these molecules in glucose-induced dysmorphogenesis and the relationship with ECM-related molecules need to be addressed.
Renal-specific oxidoreductase (RSOR), an enzyme relevant to diabetic nephropathy, is exclusively expressed in renal tubules. Studies were initiated to determine whether, like other tubule-specific proteins, it selectively modulates tubulogenesis. Northern blot analyses revealed a approximately 1.5-kb transcript, and RSOR expression was detectable in mice embryonic kidneys at day 13, gradually increased by day 17, and extended into neo- and postnatal periods. RSOR mRNA and protein expression was confined to proximal tubules, commencing at gestational day 17 and increasing subsequently, but remained absent in glomeruli and medulla. Treatment with RSOR antisense oligodeoxynucleotide resulted in a dose-dependent dysmorphogenesis of metanephric explants harvested at gestational day 13. The explants were smaller and had expanded mesenchyme, and the population of tubules was markedly decreased. The glomeruli were unaffected, as assessed by mRNA expression of glomerular epithelial protein 1 and reactivity with wheat germ agglutinin. Antisense treatment led to a selective reduction of RSOR mRNA. Immunoprecipitation also indicated a selective translational blockade of RSOR. These findings suggest that RSOR is developmentally regulated, exhibits a distinct spatiotemporal distribution, and probably plays a role in tubulogenesis.
Mesodermal-specific cDNA or transcript (MEST) was identified by suppression subtractive hybridization-PCR of cDNA isolated from embryonic day 13 vs. newborn mice kidneys. At day 13 of mouse gestation, a high expression of MEST, with a single approximately 2.7-kb transcript that was exclusively localized to the metanephric mesenchyme was observed. The MEST mRNA expression gradually decreased during the later stages and then abruptly decreased in the newborn kidneys and subsequent postnatal life, after which a very mild expression persisted in the glomerular mesangium. Regression in mRNA expression during embryonic renal development appears to be related to methylation of the MEST gene. Treatment of metanephroi, harvested at day 13 of gestation with MEST-specific antisense oligodeoxynucleotide resulted in a dose-dependent decrease in the size of the explants and the nephron population. This was associated with a selective decrease in MEST mRNA expression and accelerated apoptosis of the mesenchyme. These findings suggest that MEST, a gene with a putative mesenchymal cell-derived protein, conceivably plays a role in mammalian metanephric development.
Several novel genes that are upregulated in diabetic kidneys have been identified. Recently, transforming growth factor beta driven secreted proteins, i.e., connective tissue growth factor and gremlin (bone morphogenetic protein 2), have been identified, and their expression has been correlated with the tissue changes seen in diabetic nephropathy in the adult population. However, there are very few studies reported in the literature that describe the gene expression in the diabetic state during embryonic and neonatal life. It is well known that exposure to glucose or its epimer, i.e., mannose, induces marked dysmorphogenesis of the embryonic metanephros in an organ culture system. These changes are associated with ATP depletion and marked apoptosis, suggesting an oxidant stress in the induction of dysmorphogenesis of the embryonic metanephros. In view of the glucose-induced changes in the fetal metanephros, a diabetic state was induced by the administration of streptozotocin during pregnancy, and newborn mouse kidneys were processed for suppression subtractive hybridization-PCR. In addition, a diabetic state was induced in newborn diabetic mice, and after 1 week their kidneys were harvested and subjected to representational difference analysis of cDNA. Four novel genes with upregulated mRNA expression were identified. They included: (1) a translocase inner mitochondrial membrane 44 that is involved in the ATP-dependent import of preproteins from the cytosol into the mitochondrial matrix; (2) a kidney-specific aldo-keto reductase that utilizes NADPH and NADH as cofactors in the reduction of aromatic aldehydes and aldohexoses; (3) Rap1b, a Ras-related small GTP-binding protein that behaves as a GTPase and cycles between GTP-bound (active) and GDP-bound (inactive) states associated with conformational change, and (4) a fusion protein of ubiquitin polypeptide and ribosomal protein L40 (UbA(52) or ubiquitin/60) that is intimately involved in the ubiquitin-dependent proteasome pathway related to the accelerated degradation of proteins under various stress conditions, such as those seen in patients with cancer and diabetes mellitus.
A 64-year-old man presented with proteinuria during postoperative interferon (IFN)-beta therapy against malignant melanoma. Renal pathologic findings were consistent with minimal change nephrotic syndrome (MCNS) showing extensive foot process effacement of visceral glomerular epithelial cells (podocyte). Nephrotic range proteinuria gradually regressed after stoppage of local injection of IFN-beta without glucocorticoid treatment. To our knowledge this is the first report that demonstrates histological abnormalities of the glomerulus associated with postoperative IFN-beta therapy for the malignant melanoma.
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During the 8th month of her first pregnancy, a 40-year-old female suffered from visual disturbances. After treatment of pericarditis, which appeared 1 month after a normal delivery, she was referred to the neurosurgical department. She showed bitemporal hemianopsia, disturbance of visual acuity, and hypopituitarism. Initial computed tomography (CT) image showed a solid pituitary mass with suprasellar extension. However, 2 months later, the CT image changed to an enlarged partially cystic lesion. Transsphenoidal exploration of the sella demonstrated lymphocytic adenohypophysitis coexistent with Rathke's cleft cyst. To our knowledge, such an association has never been reported previously. Presurgical diagnosis of lymphocytic adenohypophysitis still remains difficult and surgical intervention is necessary for definitive diagnosis. However, special attention is needed for the histological diagnosis of this lesion, particularly in clinically atypical cases.