[Case of immune complex crescentic glomerulonephritis with consistently high titers of MPO-ANCA for 6 years]

A male patient, now 65 years old, experienced fever, hemoptysis, and respiratory failure about six years ago. Soon thereafter, he developed rapid progressive renal dysfunction with pulmonary hemorrhage and positive findings for MPO-ANCA. We commenced methylprednisolone pulse (MP) therapy followed by oral prednisolone (PSL) and intravenous cyclophosphamide (CY) for the treatment of ANCA-associated microscopic polyangiitis (MPA). Therapeutic efficacy was obtained comparatively rapidly. Light microscopic findings of a percutaneous renal biopsy demonstrated focal necrotizing and crescentic glomerulonephritis. Immunofluorescent microscopy indicated diffuse deposition of IgG and C3 along the periphery of the tufts and in the mesangium. On the basis of these findings, the condition was diagnosed as immune complex crescentic glomerulonephritis associated with MPO-ANCA. MPO-ANCA titers were high (714 EU) at onset and remained high (250-450 EU) over the ensuing 6 years with oral administration of PSL 5 mg. Though his condition remitted completely, his MPO-ANCA titers recently increased to above 600 EU once more. We conducted a follow-up renal biopsy to ascertain if the fluctuation of MPO-ANCA titers reflected an early stage of relapse. Light microscopic findings of the biopsied tissue revealed no signs of necrosis or crescentic formation of the glomeruli. Immunofluorescent microscopic findings were negative. The elevated MPO-ANCA titers were not valuable for the early prediction of relapse in our case, and the immune complex may have played an important role. When judging relapse and remission in ANCA-associated glomerulonephritis, it is important to evaluate the overall clinical findings and histopathological findings in addition to the serial ANCA titers.

Role of the E2F1-p19-p53 pathway in ischemic acute renal failure

BACKGROUND

Cell cycle progression and arrest of renal tubular cells after acute injury is a reactive process of renal regeneration. The p16(INK4a)/p19(ARF) (alternative reading frame) locus encodes two proteins involved in cell cycle regulation. We investigated the transcriptional regulation and tissue distribution of p19(ARF) in ischemic acute renal failure (ARF).

METHODS

We examined the time course and immunohistochemistry of p19(ARF) in rat kidneys following the induction of ischemic ARF. We also examined the effect of p19(ARF) overexpression on p53 levels and cell cycle progression in MDCK cells.

RESULTS

The protein expression of p19(ARF) strongly increased 72 h after the ischemia. Immunohistochemical studies showed that the renal tubular cells in the outer medulla expressed p19(ARF) protein 72 h after ischemic injury. The time course of E2F1 induction was observed at 6-24 h, and it was found to precede p19(ARF) expression. In MDCK cells, the overexpression of E2F1 increased promoter activity and the protein level of p19(ARF) and induced apoptosis. Transfection of the p19(ARF) expression vector caused an increase in p53 protein, cell cycle arrest and apoptosis.

CONCLUSIONS

These data support the hypothesis that the E2F1-p19(ARF)-p53 pathway forms a negative feedback loop to regulate the cell cycle of renal tubular cells in the ischemic ARF.

Expression and function of Ets-1 during experimental acute renal failure in rats

The Ets family of transcription factors is defined by a conserved DNA-binding Ets domain that forms a winged helix-turn-helix structure motif. The Ets family is involved in a diverse array of biologic functions, including cellular growth, migration, and differentiation. The hypothesis in this study was that Ets-1 is re-expressed during regeneration after acute renal failure (ARF) and plays a key role in the transcriptional regulation of cyclin D1 and the cell cycle progression in renal tubular cells. For clarifying the significance of Ets-1 in ARF, a rat ARF model in vivo and LLC-PK1 cells as an in vitro model were used. After the left rat renal artery was clamped for 1 h, the whole kidney homogenate was examined and total RNA was extracted at 6, 12, 24, 48, and 72 h after reperfusion by Western blot analysis and real-time reverse transcription-PCR. Ets-1 mRNA and protein expression were strongly increased at 6 to 24 h after the ischemia, respectively. The expression of hypoxia-inducible factor-1alpha was increased dramatically as early as 6 h after ischemia-reperfusion and decreased at 48 and 72 h after ischemia-reperfusion. In the immunohistologic examination, Ets-1 was expressed in the proximal tubules and coexpressed with proliferating cell nuclear antigen (PCNA). Furthermore, overexpression of Ets-1 promoted the cell cycle and increased the promoter activity and protein expression of cyclin D1 in LLC-PK1 cells. Ets-1 promoter activity increased between 3 and 6 h in hypoxia, and hypoxia also induced changes in the Ets-1 protein level in LLC-PK1 cells. The Ets-1 induction by hypoxia was abolished by the transfection of dominant-negative hypoxia-inducible factor-1alpha. A gel shift assay demonstrated that Ets-1 binds to the ets-1 binding site of the cyclin D1 promoter in the ischemia-reperfusion condition. Overexpression of Ets-1 did not significantly change the caspase 3 activity or the value of cell death ELISA in LLC-PK1 cells. Taken together, these data suggest that Ets-1 plays a key role in the cell-cycle progression of renal tubules in ARF. The Ets-1 pathway may regulate the transcription of cyclin D1 and control the regeneration of renal tubules in ARF.

The PI3-kinase-Akt pathway promotes mesangial cell survival and inhibits apoptosis in vitro via NF-kappa B and Bad

While the serine/threonine protein kinase Akt has attracted attention as a mediator of survival (anti-apoptotic) signal, the regulation and function of the PI3-kinase-Akt pathway in mesangial cells is not well known. To explore the significance of the PI3-kinase-Akt pathway, this study used PI3-kinase inhibitors (Wortmannin and LY294002) and recombinant adenoviruses encoding a dominant-active mutant of Akt (AxCAmyrAkt) and a dominant-negative mutant of Akt (AxCAAkt-AA) in cultured rat mesangial cells. Apoptotic signals were measured by nucleosomal laddering of DNA, caspase 3 assay, and cell death detection ELISA. The PI3 kinase inhibitors and dominant-negative mutant of Akt increased the apoptotic signals in the presence of platelet-derived growth factor (PDGF), while the dominant-active mutant of Akt prevented apoptosis induced by a serum-free medium. In separate experiments, we further investigated downstream signals of Akt in mesangial cells. While PDGF activated NF-kappa B and phosphorylated Bad, these reactions were inhibited by overexpression of the dominant-negative mutant of Akt as well as the PI3-kinase inhibitors. These data indicate, firstly, that Akt is phosphorylated by PDGF, and secondly, that the activated Akt prevents apoptotic changes via activation of NF-kappa B and phosphorylation of Bad in mesangial cells. This study investigated whether it is Bad phosphorylation or NF-kappa B activation that provides the anti-apoptotic effects of Akt, and the data suggested that NF-kappa B is probably the principal contributor to the downstream activation of the PI3-kinase-Akt pathway. The findings suggest that the PI3-kinase-Akt pathway acts as a survival signal and plays a key role in the regulation of apoptotic change in mesangial cells principally via NF-kappa B.

Expression and function of the developmental gene Wnt-4 during experimental acute renal failure in rats

The Wnt-beta-catenin pathway plays key roles in embryogenesis. Wnt-4 is known to be expressed in the mesonephric duct in embryonic development. It is tempting to speculate that the Wnt-4-beta-catenin pathway contributes to the recovery from acute renal failure (ARF). This study used an in vivo model of ARF rats to clarify the significance of the Wnt-4-beta-catenin pathway in ARF. ARF was induced by clamping the rat left renal artery for 1 h. At 3, 6, 12, 24, 48, and 72 h after reperfusion, whole kidney homogenate and total RNA were extracted for examination by Western blot analysis and real-time RT-PCR. Wnt-4 mRNA and protein expression were strongly increased at 3 to 12 h and 6 to 24 h after ischemia, respectively. In immunohistologic examination, Wnt-4 was expressed in the proximal tubules and co-expressed with aquaporin-1, GM130, and PCNA. Cyclin D1 and cyclin A were expressed at 24 to 48 h after reperfusion. In addition, the overexpression of Wnt-4 and beta-catenin promoted the cell cycle and increased the promoter activity and protein expression of cyclin D1 in LLC-PK1 cells. Taken together, these data suggest that the Wnt-4-beta-catenin pathway plays a key role in the cell cycle progression of renal tubules in ARF. The Wnt-4-beta-catenin pathway may regulate the transcription of cyclin D1 and control the regeneration of renal tubules in ARF.

Ligand-regulatable erythropoietin production by plasmid injection and in vivo electroporation

BACKGROUND

The development of an in vivo gene transfer approach to deliver physiologic levels of recombinant proteins to the systemic circulation would represent a significant advance in the treatment of protein deficiency disorders. However, the ability to regulate transgene expression is of paramount importance for safe and effective gene transfer therapy.

METHODS

We developed two plasmids, one encoder of chimeric GeneSwitch protein, and the other an inducible transgene for human erythropoietin (Epo). The level of secretion of Epo into the serum was modulated by intraperitoneal administration of mifepristone (MFP). Rats were divided into four groups: one group administered Epo plasmid with MFP for 50 days, a second group administered Epo plasmid with MFP for 15 days and then again from day 30 to day 50, a third group administered Epo plasmid without MFP, and a fourth group administered control plasmid. A pair of electrodes was inserted into the muscle of the right thigh, 100 mg of each plasmid was injected, and in vivo electroporation (8 pulses at 100 V for 50 msec) was performed.

RESULTS

The presence of vector-derived Epo mRNA was detected by RT-PCR only in the Epo plasmid and MFP(+) groups. The hematocrit levels increased continuously, from the pre-injection level of 41.2% to 55.0% on day 30 and 53.8% on day 50 in the Epo plasmid and MFP(+) groups. In the MFP re-challenged group, the hematocrit levels rose up to day 15, fell after 20 to 30 days, and then rose again after MFP re-administration. The serum Epo levels increased only in the Epo plasmid and MFP(+) groups. There were no significant changes in hematocrit levels and Epo levels in the Epo plasmid and MFP(-) group.

CONCLUSION

Epo gene transfer with the GeneSwitch system by in vivo electroporation is a useful procedure for efficient drug-regulated delivery of Epo.

Smad7 mediates transforming growth factor-beta-induced apoptosis in mesangial cells

BACKGROUND

In addition to inhibiting cell growth, transforming growth factor-beta (TGF-beta) has recently been reported to induce apoptosis in various cell lines. Smad proteins are the downstream effectors of TGF-beta signaling. Among them, Smad7 exerts negative feedback control over the action of TGF-beta. However, we do not know how the Smad proteins contribute to TGF-beta-induced apoptosis in mesangial cells. To investigate the function of Smad proteins, we examined the effect of Smad overexpression using adenoviral vector in mesangial cells.

METHODS

Primary cultured rat mesangial cells were transfected with Smad7-promoter-luciferase-plasmid by electroporation. Smad7 promoter activity was investigated by luciferase assay. The apoptotic phenomena elicited by TGF-beta and Smad7 overexpression were investigated using adenoviral vector (AdCMV-Smad7). Apoptosis was detected by the cell death detection ELISA assay, CPP32/caspase-3 assay, and nucleosomal DNA laddering.

RESULTS

TGF-beta significantly increased the protein expression and the promoter activity of Smad7 in rat mesangial cells. Overexpression of Smad7 induced DNA fragmentation and significant increases in cell death ELISA and CPP32/caspase-3 assay. On the other hand, overexpression of Smad2 and Smad3 did not elicit any significant increases in CPP32/caspase-3 activity. Furthermore, the antisense oligonucleotide to Smad7 prevented the TGF-beta-induced apoptosis. Overexpression of Smad7 did not affect nuclear factor-kappaB activity in mesangial cells.

CONCLUSIONS

These data indicate that TGF-beta-induced apoptosis in mesangial cells is mediated through the activation of caspase-3 by Smad7, but not by Smad2 or Smad3. Our results provide new clarification on the function of Smad7 in TGF-beta signaling in mesangial cells.

Efficient and ligand-dependent regulated erythropoietin production by naked dna injection and in vivo electroporation

The development of an in vivo gene transfer approach to deliver physiologic levels of recombinant proteins to the systemic circulation would represent a significant advance in the treatment of protein deficiencies-disorders. However, the ability to regulate transgene expression will become paramount for safety and efficacy in gene transfer therapy. We have described the construction of an efficient and ligand-dependently regulated erythropoietin (EPO) production system using naked plasmid and in vivo electroporation. Two plasmids, one encoding the chimeric GeneSwitch protein and the other encoding an inducible transgene for human EPO, were developed. Modulation of the level of secretion of EPO into the serum was achieved by intraperitoneal administration of mifepristone (MFP). Rats were divided into 4 groups: one group received EPO plasmid with MFP for 30 days, a second group received with EPO plasmid MFP for 9 days, a third group received EPO plasmid without MFP, and a fourth group received control plasmid. A pair of electrodes was inserted into the muscle of the right thigh and 100 micrograms of each plasmid was injected. In vivo electrporation (8 times at 100 V for 50 milliseconds) was performed. The presence of vector-derived EPO mRNA was detected by reverse transcriptase-polymerase chain reaction only in the EPO and MFP(+) group. The hematocrit levels increased continuously from the preinjection level of 42.7% to 53.8% on day 28 in the EPO and MFP(+) group. The serum EPO levels increased only in the EPO and MFP(+) group. There was no significant change in hematocrit levels and EPO levels in the EPO and MFP(-) group. These results demonstrate that EPO gene transfer with the GeneSwitch system by in vivo electroporation is a useful procedure for efficient and drug-dependent regulated delivery of EPO.

Glucocorticoids stimulate p21(CIP1) in mesangial cells and in anti-GBM glomerulonephritis

BACKGROUND

Glucocorticoids are widely used for the treatment of glomerulonephritis, but the mechanism of cell cycle inhibition by glucocorticoids is poorly understood at a molecular level.

METHODS

The effects of dexamethasone on cell cycle progression were examined in rat mesangial cells. To investigate the mechanisms of cell cycle inhibition by dexamethasone, we transfected the -2.3 kb p21(CIP1) promoter-CAT construct to mesangial cells using an electroporation

METHOD

We also examined whether glucocorticoids stimulate the expression of p21(CIP1) and inhibit cell proliferation in glomeruli of anti-glomerular basement membrane (GBM) glomerulonephritis in rats.

RESULTS

Dexamethasone inhibited 3H-thymidine uptake and the percentages of S and G2/M phases in rat mesangial cells. Dexamethasone stimulated CAT activity of the p21(CIP1) promoter 4.5-fold. Deletion analysis of the p21(CIP1) promoter revealed that the glucocorticoid-responsive region (GRE) is present between -1.4 and -1.1 kb upstream of the transcription initiation site. Dexamethasone inducibility of p21(CIP1) promoter activity requires the presence of the C/EBP alpha DNA binding site in the GRE of the p21(CIP1) promoter and C/EBP alpha protein. Intravenous injection of anti-GBM antibody caused mesangial proliferation, crescent formation, and proteinuria in rats. Ten days of administration of prednisolone (1 mg/kg/day) reduced proteinuria and inhibited mesangial cell proliferation and crescent formation. The glomerular-sieving method revealed that prednisolone increased p21(CIP1) expression in glomeruli.

CONCLUSION

These data suggest that the cell cycle arrest of mesangial cells is mediated by a functional link between the glucocorticoid receptor and the transcriptional control of p21(CIP1) not only in vitro but also in vivo. Our observations provide new insights into the molecular mechanisms of glucocorticoid action in glomerulonephritis.

Seasonal changes in human sleep-wake rhythm in Antarctica and Japan

The subjects were eight men of the Japanese Antarctic Research Expedition (average age 35.8 years), and 10 healthy people living around Kofu, Japan (28.9 years). They completed a sleep log for 12 to 18 months, and the sleep-wake state was scored in 10-min epochs. Q24 values calculated by chi2 periodgram were low in the Antarctic midwinter. This means that there was difficulty in synchronizing to a 24-h period in the Antarctic midwinter. In Antarctica, sleep onset and offset times were delayed mostly in the midwinter. In Japan, sleep offset time was delayed mostly around the winter solstice.

Validity of sleep log compared with actigraphic sleep-wake state II

Twenty-five young people (Y group), three elderly people and seven people with various sleep disorders (SD group) kept a sleep log for 2-7 days, and their wrist-activity was monitored simultaneously. The sensitivity and specificity of the sleep log, and the ratio of agreement between the sleep log and actigraphic sleep-wake state were calculated. The sensitivity and specificity in Y group were 87.93+/-6.49% and 96.51+/-2.37%, respectively. The sensitivity in SD group was significantly lower than in Y group. Even in Y group one-hour agreement ratios dropped during the sleep onset period.

A novel cell-free system for peptide synthesis driven by pyridine

Previously we demonstrated that ribosomes can synthesize polypeptides in the presence of high concentrations (40-60%) of pyridine without any protein factors. Here we analyze additional ribosomal parameters in 60% pyridine using Escherichia coli ribosomes. Ribosomal subunits once exposed to pyridine failed to re-associate to 70S ribosomes in aqueous buffer systems even in the presence of 20 mM Mg2+, whereas they formed 70S complexes in the presence of 60% pyridine. Two-dimensional gel electrophoresis of ribosomal proteins revealed that some proteins located at the protuberances of the large subunit, e. g. L7/L12 and L11 forming the elongation factor-binding domain, were released in the pyridine system. The aminoglycoside neomycin, a strong inhibitor of the ribosomal (factor-independent) translocation reaction, completely blocked poly(Phe) synthesis and translocation activities in the pyridine system, whereas these activities were not affected at all by gypsophilin, a ribotoxin that inhibits factor-dependent translocation. Another inhibitor of the ribosomal translocation, thiostrepton, had no effect concerning the two activities, which is consistent with the fact that this antibiotic requires L11 for its binding to the ribosome. These results suggest that the ribosomes can perform a translocation reaction in the pyridine system, but in a factor-independent (spontaneous) manner.

Validity of sleep log compared with actigraphic sleep-wake state

Seven women and 11 men, mean age 30.1 years, kept a sleep log for 5-7 days, and their wrist activity was monitored each minute. Sleep-wake state in the sleep log and actigraphic sleep-wake state were compared, and the sensitivity and specificity of the sleep log were calculated for each subject. The ratio of agreement between these two parameters was computed for each subject. The sensitivity and specificity of the sleep log were 72.73-97.56% (mean 86.71%) and 92.85-99.68% (mean 97.04%), respectively. The agreement ratio was 87.30-97.85% (93.48%), but 1-h agreement ratios from midnight dropped during the sleep onset period.

Enzyme-linked immunosorbent assay for human autoantibody to glial fibrillary acidic protein: higher titer of the antibody is detected in serum of patients with Alzheimer's disease

We have developed an enzyme-linked immunosorbent assay (ELISA) to detect anti-glial fibrillary acidic protein (GFAP) autoantibody in human sera. The ELISA was prepared by coating microtest plates with purified GFAP from bovine spinal cord. The autoantibody activities were assayed in the serum from 219 control subjects, 39 Alzheimer's disease patients and 39 cerebrovascular dementia patients. Higher titer of the antibody was observed in the serum of Alzheimer's disease patients. Since the titer showed no significant change with aging or with sex in the control serum, we could determine a certain normal value of the antibody titer. The percentage of abnormal subjects whose antibody levels were over the normal value was 53.8% in Alzheimer's disease (presenile onset) patients, 30.8% in Alzheimer's disease (senile onset) patients, 10.3% in cerebrovascular dementia patients and 5.5% in control subjects. We discuss the relationship between the anti-GFAP autoantibody and the pathogenesis of Alzheimer's disease and suggest that the evaluation of anti-GFAP autoantibody level may be useful in diagnosing Alzheimer's disease.