Fumiaki Nogaki

Notch1 and Notch3 Instructively Restrict bFGF-Responsive Multipotent Neural Progenitor Cells to an Astroglial Fate

Notch1 has been shown to induce glia in the peripheral nervous system. However, it has not been known whether Notch can direct commitment to glia from multipotent progenitors of the central nervous system. Here we present evidence that activated Notch1 and Notch3 promotes the differentiation of astroglia from the rat adult hippocampus-derived multipotent progenitors (AHPs). Quantitative clonal analysis indicates that the action of Notch is likely to be instructive. Transient activation of Notch can direct commitment of AHPs irreversibly to astroglia. Astroglial induction by Notch signaling was shown to be independent of STAT3, which is a key regulatory transcriptional factor when ciliary neurotrophic factor (CNTF) induces astroglia. These data suggest that Notch provides a CNTF-independent instructive signal of astroglia differentiation in CNS multipotent progenitor cells.

Increased Frequency of Surface IgA-Positive Plasma Cells in the Intestinal Lamina Propria and Decreased IgA Excretion in Hyper IgA (HIGA) Mice, a Murine Model of IgA Nephropathy with Hyperserum IgA

Because abnormalities of mucosal immunity have been suggested in human IgA nephropathy, we examined the involvement of mucosal immunity in IgA deposition to the kidney in hyper IgA (HIGA) mice, which was established as a mouse model for human IgA nephropathy with hyperserum IgA. The number of surface IgA+B220− lymphocytes in the intestinal lamina propria (LP) of HIGA mice increased 2.7-fold at 30 wk of age as compared with those at 10 wk of age, whereas normal mice did not show such increase. The surface IgA+B220− LP lymphocytes spontaneously secreted IgA in culture. Morphological studies showed that the surface IgA+B220− lymphocytes of murine intestinal LP are identical with plasma cells (PCs). About 20% of IgA+B220− PC in LP expressed both Mac-1 and CD19, suggesting that they may derive from peritoneal B-1 cells. Cell cycle study on intestinal IgA-PCs using bromodeoxyuridine revealed no difference between HIGA mice and normal mice, suggesting that the high frequency of IgA-producing PCs in HIGA mice is not due to enhanced proliferation or prolonged survival of IgA-producing PCs in LP. In addition, IgA secretion into the gut lumen of HIGA mice decreased drastically (to one forth) with aging. These data suggest that the increased number of intestinal IgA-producing PCs and the down-regulation of IgA excretion into the intestinal lumen might synergistically contribute to the hyperserum IgA in HIGA mice and resultant IgA deposition to the kidney.

Clinical efficacy of intravenous immunoglobulin for patients with MPO-ANCA-associated rapidly progressive glomerulonephritis

Background: To determinewhether intravenous immunoglobulin (IVIg) cancontrol disease activity in patients with myeloperoxidase-antineutrophil cytoplasmic antibody (MPO-ANCA)-associated rapidly progressive glomerulonephritis (RPGN). Methods: Twelve patients with serologically and histologically confirmed MPO-ANCA-associated RPGN (7 men, 5 women; mean age 71 ± 3 years) received IVIg (400 mg/kg/day) alone for 5 days. The effects of IVIg were evaluated by white blood cell counts, serum C-reactive protein levels, Birmingham Vasculitis Activity Score, rate of change in reciprocal creatinine (1/Cre), and plasma tumor necrosis factor-α levels after IVIg administration. Corticosteroids with or without cyclophosphamide were commenced after IVIg. Results:After IVIg treatment, a significant decrease was observed in white blood cell count (p < 0.05), C-reactive protein values (p < 0.001), and Birmingham Vasculitis Activity Score (p < 0.001) concomitant with the amelioration of systemic symptoms. The rate of change in 1/Cre significantly improved (p < 0.05). Plasma tumor necrosis factor-α levels that were significantly elevated in patients before IVIg compared with normal controls (p < 0.0001), rapidly declined after IVIg with a significant reduction(p < 0.05). Three months post-treatment with IVIg, all patients showed improvement of disease without serious infectious complications. Conclusion: IVIg is a potential component of remission induction therapy for patients with MPO-ANCA-associated RPGN.

Roles of coagulation pathway and factor Xa in rat mesangioproliferative glomerulonephritis.

Tissue factor initiates the extrinsic coagulation pathway by activating coagulation factor X to factor Xa, and factor V is a cofactor for the prothrombin activation by factor Xa. As factor Xa is known to promote the proliferation of mesangial cells in culture, the roles of the coagulation pathway and factor Xa were studied in an animal model of mesangioproliferative glomerulonephritis (MsPGN). MsPGN was induced in Wistar rats by an intravenous injection of anti-Thy 1.1 monoclonal antibody, OX-7. To clarify the role of factor Xa in MsPGN, a specific factor Xa inhibitor, DX-9065a, was injected intravenously at 2.5 or 10 mg/kg at the same time as OX-7, and kidney involvement was assessed by immunohistological analyses. We also examined p44/42 mitogen-activated protein (MAP) kinase activation. Time-course study revealed that expressions of tissue factor, factor V, and protease-activated receptor 2 (PAR2) were peaked on day 3, followed by factor X accumulation and mesangial proliferation. DX-9065a treatment significantly ameliorated proteinuria in a dose-dependent manner on day 8. Histological analyses showed a significant reduction in the size of glomeruli, the total number of glomerular cells, and crescent formation by DX-9065a treatment. Macrophage infiltration, which was rapidly observed on day 1 in disease control rats was not inhibited on days 1–3 by DX-9065a treatment, however it was suppressed on days 5–8. The deposition of fibrin, the number of PCNA-positive cells, and phosphorylation of p44/42 MAP kinase were markedly increased in the disease control group, whereas they were significantly reduced in the treatment group. Tissue factor and factor V induction may accelerate MsPGN through the activation and accumulation of factor X via proinflammatory and procoagulant mechanisms, and the inhibition of factor Xa would be a promising method to regulate the disease process.

Suppressive Mechanisms of Sairei-to on Mesangial Matrix Expansion in Rat Mesangioproliferative Glomerulonephritis

Background: Sairei-to (TJ-114) is a Japanese herbal medicine of standardized quality, originating from traditional Chinese medicine. In the present in vivo study, we investigated the suppressive effects of TJ-114 and related drugs, Shosaiko-to (TJ-9), and Saiboku-to (TJ-96), on mesangioproliferative glomerulonephritis (MsPGN) in rats. TJ-9 is a basal prescription of TJ-96 and TJ-114. We evaluated the efficacy of these drugs on proteinuria, extracellular matrix (ECM) accumulation, and superoxide dismutase (SOD)-activity. Methods: MsPGN in Wistar rats was induced by intravenous injection of rabbit anti-rat thymocyte serum (ATS). TJ-114, TJ-9, TJ-96 (500 mg/kg/day), or prednisolone (PSL, 2 mg/kg/day) was orally administered to the rats as drinking water from the day of ATS injection (day 0) to day 8, when rats were sacrificed and the kidney specimens were collected. Macrophage infiltration was evaluated by immunostaining for ED-1. ECM was measured by trichrome-staining, and fibronectin immunostaining. Northern blotting was performed to clarify the mRNA expression of cytokines and fibronectin. SOD-activity in the homogenate of renal cortex was also evaluated. Results: The amount of urinary protein was significantly decreased only in the TJ-114-treated group compared with the disease control group (p < 0.05). The number of ED-1-positive cells was significantly decreased in all the treatment groups (p < 0.05, respectively). Decreases in the trichrome-stained area were observed moderately in the TJ-114-treated group (66% of control, p < 0.001) and mildly in the PSL-treated group (76% of control, p < 0.001). The staining area of fibronectin in the glomerulus was significantly decreased in all the treated groups except PSL, and was especially suppressed in the TJ-114-treated group (45% of control, p < 0.001). Transforming growth factor (TGF) and connective tissue growth factor (CTGF) expression significantly decreased in the TJ-114-treated group to the control level (p < 0.05). TGF-β, CTGF, and fibronectin mRNA were upregulated in the disease control group, and TJ-114 suppressed these mRNA expressions in glomeruli. The SOD-activity of renal cortex-homogenate was significantly augmented in all the treated groups except PSL, markedly in the TJ-96- and TJ-114-treated groups. Conclusion: These results suggest that TJ-114 ameliorates ECM accumulation in experimental rat MsPGN, partly suppressing TGF-β and CTGF expression through the recovery of SOD-activity.

Broad Antiproliferative Effects of Benidipine on Cultured Human Mesangial Cells in Cell Cycle Phases

Background and Purpose: Recently, in vitro studies have shown that some calcium channel blockers inhibit the proliferation of mesangial cells. In the present study, we evaluated the antiproliferative effects of benidipine, a calcium channel blocker, in comparison with other calcium channel blockers, and attempted to further clarify its mechanism of action on cultured human mesangial cells in relation to cell cycle. Methods: Human mesangial cells were cultured in medium containing 5% fetal calf serum (FCS), with or without benidipine, or other calcium channel blockers for 20 h, and [3H]thymidine incorporation were measured. Analysis of cell cycle dependency was carried out, using platelet-derived growth factor as a competence factor, which transfers cells from the G0 to the G1 (G0/G1) phase, and insulin as a progression factor, which transfers cells from the G1 to the S (G1/S) phase. Cells were also analyzed by flow cytometry. Results: Benidipine and nifedipine showed significant inhibitory effects on FCS-induced proliferation (p < 0.001 and p < 0.01, respectively, by ANOVA), with 3.8 and 41.9% of the control level of [3H]thymidine incorporation at the concentration of 10 µM of the blockers, respectively. Diltiazem had no inhibitory effect at this concentration. Benidipine was found to inhibit cells in both the boundaries of G0/G1 and G1/S phases (p < 0.001 and p < 0.0001, respectively), whereas nifedipine inhibited only cells in G1/S phase (p < 0.05). The effects of benidipine (10 µM) on cells in G1/S were stronger than those on cells in the G0/G1 phase (p < 0.0001). Furthermore, flow cytometry showed that 10 mM benidipine significantly inhibited the G1 to S phase transition of FCS-stimulated mesangial cells (p < 0.03). Conclusions: Benidipine markedly inhibited the proliferation of mesangial cells, at both the G0/G1 and G1/S phases, and it might be effective to suppress the progression of mesangioproliferative glomerular diseases.

Sairei-to Ameliorates Rat Peritoneal Fibrosis Partly through Suppression of Oxidative Stress

Background: Sairei-to is a herbal prescription originating from traditional Chinese medicine. We conducted an experimental study on rat peritoneal fibrosis to clarify the suppressive mechanisms of sairei-to. Methods: Wistar rats were intraperitoneally injected with chlorhexidine gluconate (CG) every day. Peritoneal specimens were collected after 28 days of CG injection and oral administration of sairei-to. Macrophage infiltration, extracellular matrix accumulation, and angiogenesis were evaluated by immunostaining for ED-1, fibronectin, and CD-31, respectively. To observe oxidative stress in the tissue, 4-hydroxy-2-noneal (HNE) accumulation and plasma levels of superoxide dismutase (SOD) activity were detected. As a candidate of antioxidative components in sairei-to, plasma levels of baicalin were determined by high-performance liquid chromatography. Results: Compared with the disease control group, serum total protein levels were significantly recovered in the sairei-to treatment group. Thickness of the submesothelial compact zone, trichrome-stained area, ED-1-positive cells, fibronectin-staining area, and HNE accumulation were suppressed in the treatment group. Concurrently, decreased plasma levels of SOD activity were recovered by sairei-to treatment. Increased CD-31-positive vessel number and area were also suppressed in the sairei-to group. Baicalin was detected in the plasma samples of the sairei-to group at 0.29 ± 0.11 µg/ml (mean±SEM). Conclusion: These results suggest that sairei-to ameliorates peritoneal fibrosis, partly through suppressing oxidative stress and macrophage infiltration.

Glomerulonephritis induced by methicillin-resistant Staphylococcus aureus infection that progressed during puerperal period

A 28-year-old Japanese woman developed fever, leg edema, purpura, and abdominal pain during the puerperal period, showing nephrotic syndrome with microscopic hematuria. At first she was thought to have Henoch-Shönlein purpura nephritis and was given steroids at another hospital. Because anasarca and massive urinary protein excretion developed, she was referred to our hospital. Renal biopsy specimens showed endocapillary proliferative glomerulonephritis with massive IgA and C3d deposition along the capillary loops and in the mesangium. A bacteriological study detected methicillin-resistant Staphylococcus aureus (MRSA) in cultures of vaginal secretions, urine, stool, and pharyngeal mucus samples. Based on the diagnosis of MRSA nephritis, anti-MRSA therapy with antibiotics was started, and MRSA became negative for each culture, and urinary protein decreased. Two months after the first renal biopsy, a second renal biopsy was performed, which revealed feeble endocapillary proliferation with mild IgA and C3d deposition in the mesangium. This case showed that the delivery procedure can cause MRSA nephritis after MRSA infection, and that steroid therapy should be avoided in the early phase of this type of nephritis.

Heminephrectomy Causes the Progression of Glomerulosclerosis and Apoptosis in High IgA Strain ddY Mice

Background: The reduction in nephrons in IgA nephropathy is critical to the prognosis of this disease. However, the immunopathological mechanism of the modifications seen in glomerular lesions is not clear. We thus investigated the influence of nephron reduction by heminephrectomy on renal lesions in a high immunoglobulin A inbred strain of ddY mouse (HIGA mouse), which shows progressive mesangial sclerosis with elevated renal expression of transforming growth factor (TGF)-β. Methods: Five-week-old HIGA mice were heminephrectomized (Nx), and were evaluated in comparison with a sham-operated group (S) at 40 weeks old. Histological findings, immunoglobulin depositions (IgG, IgA, and IgM), and expressions of cytokine and extracellular matrix proteins (TGF-β, fibronectin, collagen type I and IV) were analysed. PCNA and TUNEL stainings were performed with electron microscopic detection of apoptosis. Tissue renin-angiotensin systems (RAS) were also investigated by real-time quantitative RT-PCR. Results: In the Nx group, the glomerular tuft area and ratio of mesangial matrix area per tuft were significantly increased, and the glomerular cell count per tuft area was significantly decreased. Glomerular immunoglobulin deposits of IgG, IgA, and IgM in Nx were all significantly expanded in the paramesangium. The glomerular expressions of TGF-β and the extracellular matrix proteins were significantly increased in Nx mice. In contrast to the significant decrease of PCNA-positive cells, TUNEL-positive cells were significantly increased in Nx. Angiotensin-converting enzyme (ACE) was significantly increased in the renal cortex of Nx. Conclusion: Simple heminephrectomy, other than 5/6 renal ablation, of HIGA mice may be a potential model for research into the progressive glomerulosclerosis of human IgA nephropathy. The pathological role of apoptosis is apparently involved in these disease processes, possibly through upregulated RAS.

Renal redox dysregulation in AKI: application for oxidative stress marker of AKI

Oxidative stress is a major determinant of acute kidney injury (AKI); however, the effects of an AKI on renal redox system are unclear, and few existing AKI markers are suitable for evaluating oxidative stress. We measured urinary levels of the redox-regulatory protein thioredoxin 1 (TRX1) in patients with various kinds of kidney disease and in mice with renal ischemia-reperfusion injury. Urinary TRX1 levels were markedly higher in patients with AKI than in those with chronic kidney disease or in healthy subjects. In a receiver operating characteristic curve analysis to differentiate between AKI and other renal diseases, the area under the curve for urinary TRX1 was 0.94 (95% confidence interval, 0.90-0.98), and the sensitivity and specificity were 0.88 and 0.88, respectively, at the optimal cutoff value of 43.0 μg/g creatinine. Immunostaining revealed TRX1 to be diffusely distributed in the tubules of normal kidneys, but to be shifted to the brush borders or urinary lumen in injured tubules in both mice and humans with AKI. Urinary TRX1 in AKI was predominantly in the oxidized form. In cultured human proximal tubular epithelial cells, hydrogen peroxide specifically and dose dependently increased TRX1 levels in the culture supernatant, while reducing intracellular levels. These findings suggest that urinary TRX1 is an oxidative stress-specific biomarker useful for distinguishing AKI from chronic kidney disease and healthy kidneys.