[Show abstract][Hide abstract] ABSTRACT: Mice with cardiac-specific overexpression of signal transducer and activator of transcription 3 (STAT3) are resistant to doxorubicin-induced damage. The STAT3 signal may be involved in the detoxification of reactive oxygen species (ROS).
The effects of leukemia inhibitory factor (LIF) or adenovirus-mediated transfection of constitutively activated STAT3 (caSTAT3) on the intracellular ROS formation induced by hypoxia/reoxygenation (H/R) were examined using rat neonatal cardiomyocytes. Either LIF treatment or caSTAT3 significantly suppressed the increase of H/R-induced ROS evaluated by 2',7'-dichlorofluorescin diacetate fluorescence. To assess whether ROS are really involved in H/R-induced cardiomyocyte injury, the amount of creatine phosphokinase in cultured medium was examined. Both LIF treatment and caSTAT3 significantly decreased H/R-induced creatine phosphokinase release. These results indicate that the gp130/STAT3 signal protects H/R-induced cardiomyocyte injury by scavenging ROS generation. To investigate the mechanism of scavenging ROS, the effects of LIF on the induction of antioxidant enzymes were examined. LIF treatment significantly increased the expression of manganese superoxide dismutase (MnSOD) mRNA, whereas the expression of the catalase and glutathione peroxidase genes were unaffected. This induction of MnSOD mRNA expression was completely blocked by adenovirus-mediated transfection of dominant-negative STAT3. Moreover, caSTAT3 augmented MnSOD mRNA and its enzyme activity. In addition, the antisense oligodeoxyribonucleotide to MnSOD significantly inhibited both LIF and caSTAT3-mediated protective effects.
The activation of STAT3 induces a protective effect on H/R-induced cardiomyocyte damage, mainly by inducting MnSOD. The STAT3-mediated signal is proposed as a therapeutical target of ROS-induced cardiomyocyte injury.
[Show abstract][Hide abstract] ABSTRACT: Environmental factors essential for the first stages of B lymphopoiesis remain elusive. Here, we report that immediately after commitment to B lineage, precursors become dependent on a chemokine SDF-1 and its receptor CXCR4 using mutant and radiation chimeric mice. In bone marrow, generation of the earliest identifiable B cell precursor populations requires CXCR4. In fetal liver, we identified Lin(-)CD19(-)c-kit(+)IL-7Ralpha(+)AA4.1(+), the earliest unipotent B cell precursor population, and found that its development was severely affected in SDF-1(-/-) embryos but not in IL-7(-/-) embryos. Lin(-) T cell progenitors appeared normal in SDF-1(-/-) embryos. Moreover, SDF-1 exhibited specific biologic activities on the earliest B cell precursors. SDF-1 provides the first example of a cytokine responsible for the earliest B lineage stages.
[Show abstract][Hide abstract] ABSTRACT: Bone morphogenetic protein (BMP)-2 has been shown to induce ectopic expression of cardiac transcription factors and beating cardiomyocytes in non-precardiac mesodermal cells, suggesting that BMP-2 is an inductive signaling molecule that participates in cardiac development. However, direct evidence of the effects of BMP-2 on cardiac myocytes has not been reported. To examine the role of BMP-2 and its receptors, we studied the ability of BMP-2 to promote survival of isolated neonatal rat cardiac myocytes. BMP receptors IA, IB, and II and activin receptor I were found to be expressed in myocytes, and BMP-2 phosphorylated Smad1 and p38 MAPK. Interestingly, BMP-2 promoted survival and inhibited apoptosis of serum-deprived myocytes, although it did not strongly induce hypertrophic growth. To explore the mechanisms for this protective effect, an adenovirus-based vector system was used. Similar to BMP-2, Smad1 promoted survival that was repressed by Smad6. Moreover, BMP-2 and Smad1 enhanced the expression of the anti-apoptotic molecule Bcl-x(L). Antisense oligonucleotides to bcl-x(L) attenuated the survival effected by BMP-2. Overall, our findings suggest that BMP-2 prevents apoptosis of myocytes by induction of Bcl-x(L) via a Smad1 pathway and might be a novel survival factor without any hypertrophic effect on myocytes.
Journal of Biological Chemistry 09/2001; 276(33):31133-41. · 4.65 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Research indicates that aged heart-beating cadaveric donors cause greater risk factors in kidney transplantation. The influence of age on the outcome of non-heart-beating (NHB) cadaveric renal transplantations has not yet been clarified. From July 1986 to May 1999, 63 patients who received cadaveric renal transplantation at Osaka City University Hospital and Osaka City General Hospital were divided into two groups according to their age. Renal function and graft-survival rates of the two groups were compared. The mean values of nadir donor serum creatinine were significantly worse (P < 0.05) in the aged donor group. In the aged donor group the percentage of immediately functioning grafts was lower and the percentage of non-functioning grafts was higher. During the first 10 years post-transplant, graft survival in the aged donor group was significantly lower than that in the younger donor group. We conclude that cadaveric renal transplantation from NHB aged donors can be to the detriment of renal function and graft survival rates compared to transplantation from younger donors.
International Journal of Urology 08/2001; 8(8):S68-70. · 1.73 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Cernitin pollen-extract (Cernilton, CN) is a preparation made from eight kinds of pollen and has been used for various prostatic diseases in Japan and Europe. We reported previously that CN possessed a recovery action on the sex-hormone-induced nonbacterial prostatitis in rats. To clarify the possible mechanism of action of CN, we investigated the effects of CN on inflammatory cytokines (IL-1 beta, IL-6 and TNF-alpha) in the same model. Aged Wistar rats were castrated and injected 17 beta-estradiol (0.25 mg/kg/day, s.c.) for 30 days. CN (630 and 1,260 mg/kg, p.o.) or testosterone (2.5 mg/kg, s.c.) was administered for the last 14 days of the treatment of 17 beta-estradiol. In control rats, prostatic IL-6 and TNF-alpha contents were increased approximately 2-3 fold, and acinar glandular inflammation and stromal proliferation were found histopathologically, as compared with those of intact rats. On the other hand, CN decreased the increased contents of cytokines in a dose-dependent manner. The histopathological changes mentioned above were restored in rats treated with 1,260 mg/kg. Testosterone also ameliorated them significantly. These results indicate that CN has an anti-inflammatory action, and that the inhibitory effect of CN on the prostatic inflammatory cytokine is an important factor in its action.
[Show abstract][Hide abstract] ABSTRACT: We reported previously that neurofilaments (NFs) of aged rats were highly packed in the axon and contained a smaller amount of NF-M as compared with those of young rats (Uchida et al.  J. Neurosci. Res. 58:337-348). We studied NFs of the mutant mouse, named Klotho, which displays prematurely symptoms resembling human aging. The transport of axonal cytoskeletal proteins, including NFs, tubulin and actin, was decreased at the leading portion of the peak of transported proteins in Klotho during the process of premature aging. The nearest neighbor inter-NF distance in Klotho axons (35-39 nm) was shorter than that of the wild-type mouse (48-49 nm), indicating the packing of NFs in Klotho. The ratio of NF-M to NF-L was slightly decreased in cytoskeletons from the spinal cords of Klotho. These changes are similar, though not identical, to those observed in aged rats, and are the first evidence of age-related changes in the neurons of Klotho.
Journal of Neuroscience Research 06/2001; 64(4):364-70. · 2.97 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: We show that when telencephalic neural progenitors are briefly exposed to bone morphogenetic protein 2 (BMP2) in culture, their developmental fate is changed from neuronal cells to astrocytic cells. BMP2 significantly reduced the number of cells expressing microtubule-associated protein 2, a neuronal marker, and cells expressing nestin, a marker for undifferentiated neural precursors, but BMP2 increased the number of cells expressing S100-beta, an astrocytic marker. In telencephalic neuroepithelial cells, BMP2 up-regulated the expression of negative helix-loop-helix (HLH) factors Id1, Id3, and Hes-5 (where Hes is homologue of hairy and Enhancer of Split) that inhibited the transcriptional activity of neurogenic HLH transcription factors Mash1 and neurogenin. Ectopic expression of either Id1 or Id3 (where Id is inhibitor of differentiation) inhibited neurogenesis of neuroepithelial cells, suggesting an important role for these HLH proteins in the BMP2-mediated changes in the neurogenic fate of these cells. Because gliogenesis in the brain and spinal cord, derived from implanted neural stem cells or induced by injury, is responsible for much of the failure of neuronal regeneration, this work may lead to a therapeutic strategy to minimize this problem.
Proceedings of the National Academy of Sciences 06/2001; 98(10):5868-73. · 9.81 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: In order to determine the modality of prophylactic intravesical instillation of pirarubicin (THP = tetrahydropyranyladriamycin) following transurethral resection (TUR) of superficial bladder cancer, a prospective randomized study was performed. A total of 79 patients were randomized into "2-hour instillation" (A), "5-min instillation" (B) and "control" (C) groups. Prophylactic efficacy and side effects were analyzed in each group. In groups A and B, 20 mg of THP was first dissolved in 10 ml of distilled water, adjusted to 40 ml with saline and was administered intravesically once a week for 10 weeks, starting from 1 week after TUR. The recurrence-free rate was calculated in 65 evaluable patients. The one-year recurrence-free rate was 70.2% in group A, 62.8% in group B and 52.1% in group C. The one-year recurrence-free rate was significantly higher in group A than in group C. Adverse effects were observed in 21.4% of the patients in group A and 40.7% in group B. There was no significant difference in the occurrence rate of side effects between these two groups. Taking the prophylactic efficacy and side effects into consideration, "2-hour instillation" seemed to be better than "5-min instillation".
[Show abstract][Hide abstract] ABSTRACT: Interleukin-18 (IL-18), a proinflammatory cytokine, leads to IFN-gamma production by NK or T cells, induces Th1 differentiation and suppresses IgE synthesis by B cells when acting on responding cells together with IL-12. IL-18 also exhibits biological activities related to allergic inflammation such as histamine or IL-4 release from basophils and accumulation of eosinophils in localized lesions in allergic model mice. In this study, Reverse transcription (RT)-PCR analysis revealed that IL-18 receptor alpha chain mRNA was expressed in both freshly prepared eosinophils and two eosinophilic cell lines (YY-1 and EoL-1 cells). Flow cytometry and RT-PCR analyses revealed that the treatment of YY-1 cells with n-butyric acid promoted cell maturation and caused an enhancement of IL-18 receptor alpha chain expression. IL-18 had little effect on the survival of peripheral eosinophils, but it dose-dependently augmented IL-8 synthesis by YY-1 cells. In addition, IL-18-mediated up-regulation of IL-8 expression in eosinophils from a patient suffering from hyper-eosinophilic syndrome was confirmed. Our findings using peripheral blood eosinophils and eosinophilic cell line suggest the functional importance of IL-18 in the induction of IL-8 and a potential proinflammatory role in allergy.
European Journal of Immunology 05/2001; 31(4):1010-6. · 4.97 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: In Japan, the number of patients seeking kidney transplants has declined in recent years. To investigate the reasons for this decline, a questionnaire was given to 73 haemodialysis patients treated at the Tokiwa-Tatsumi Clinic. The resulting data showed the percentage of patients seeking transplants declined from 61% in 1992 to 19.2% in 1999. The reasons given for not seeking transplants were the improvements of physical condition and resultant quality of life (QOL) due to progress in dialysis therapy, upgraded social welfare support, uncertainties of transplant medicine, loss of expectations due to limited availability of transplant kidneys and aging of patients. Meanwhile, the number of patients on dialysis continues to increase by approximately 10,000 a year, and the mean age of patients rises. To reduce this number, greater effort must be directed toward preventive medical care as well as educating the public regarding transplant medicine.
[Show abstract][Hide abstract] ABSTRACT: Many case-control and cohort studies have shown a positive relationship between bladder carcinoma and tobacco use. Recently, urine pH has been reported to influence aromatic amine carcinogenesis, which have been implicated as potent carcinogens in bladder carcinoma patients. Herein the correlation between bladder carcinoma, tobacco use and urine pH is reported.
One hundred and forty-one patients with bladder carcinoma and 128 patients with benign prostatic hyperplasia or urolithiasis as controls were selected. All patients were admitted to Osaka City University Hospital for the purpose of surgical treatment. Urine pH was checked by a test tape.
Of the patients with bladder carcinoma, 106 were smokers and 35 were non-smokers. In contrast, the number of smokers in the control group was 76 and that of non-smokers was 52. The odds ratio in the bladder carcinoma group calculated for the smoker patients was 2.07, showing a significant correlation between bladder carcinoma and tobacco use. Regarding urine pH, acidic urine was found in 126 patients in the bladder carcinoma group and in 116 patients in the control group. The odds ratio in the bladder carcinoma group for acidic urine was 0.87, showing no significant relationship between bladder carcinoma and urine pH.
The study found a positive relationship between bladder carcinoma and tobacco use; however, it could not establish a clear relationship between bladder carcinoma and urine pH, even in the smoker group.
International Journal of Urology 04/2001; 8(3):106-9. · 1.73 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Functional roles of interleukin (IL-)6 in T cell response were investigated. Mice deficient in IL-6 and wild mice were immunized with antigens (myelin oligodendrocyte glycoprotein or methylated BSA) and production of IL-4 and interferon (IFN)-gamma by regional lymph nodes was measured. IL-6 deficiency led to an enhancement of IL-4 and an inhibition of IFN-gamma production. Moreover, polyclonal stimulation of spleen T cells from unimmunized IL-6-deficient mice with anti-CD3 plus anti-CD28 antibodies (Abs) demonstrated an enhancement of T helper (Th)(2)responses. The presence of IL-6, however, augmented IL-4 production but it inhibited IFN-gamma expression by spleen T cells in response to polyclonal stimulation and by antigen-primed spleen T cells in response to re-challenge with the antigen. In contrast, the induction of spleen CD4-positive T cells into Th(2)cells in vitro by the anti-CD3 plus IL-4 was completely suppressed by exogenously added IL-6, whereas Th(1)differentiation of T cells by the anti-CD3 plus IL-12 was not inhibited by the presence of IL-6. Thus, these results indicate that IL-6 physiologically could modulate qualitative T cell response and suggest that it augments Th(1)responses partly through its inhibitory capability of IL-4-induced Th(2)differentiation of naive T cells.
[Show abstract][Hide abstract] ABSTRACT: -It has been shown that ovarian steroid hormones can reduce the incidence of cardiovascular disease in postmenopausal women. As hormone replacement therapy for postmenopausal women, progestins are added to estrogens to eliminate the increased risk of endometrial cancer. However, the effects of progestins on the atherogenic process have not been well understood. In the present study, we examined the effects of progestins on the expression of vascular cell adhesion molecule-1 (VCAM-1) in human umbilical vein endothelial cells (HUVECs). Immunocytochemical analysis revealed the presence of progesterone receptors in HUVECs. Progesterone clearly inhibited tumor necrosis factor-alpha-activated expression of VCAM-1 protein and its mRNA in HUVECs. Synthetic progesterone receptor agonist R5020 also inhibited the tumor necrosis factor-alpha-activated VCAM-1 expression, whereas medroxyprogesterone acetate (MPA) failed to do so. Electrophoretic mobility shift assays demonstrated that progesterone, but not MPA, inhibited DNA binding of the transcription nuclear factor-kappaB, which is critical for the inducible expression of VCAM-1. Because the expression of VCAM-1 is one of the earliest events that occurs in the atherogenic process, this adhesion molecule might be a target molecule for progesterone on vascular walls. The contrasting effects of progesterone and MPA seem clinically important, inasmuch as MPA is a widely used progestin in the regimen of hormone replacement therapy.
[Show abstract][Hide abstract] ABSTRACT: Btk is a critical molecule in B cell antigen receptor (BCR)-coupled signaling, and its activity is regulated by Lyn and Syk. Although the molecular mechanism of Lyn-dependent Btk activation has been investigated, that of Syk-dependent Btk activation has remained unidentified. We have demonstrated that BLNK mediates Syk-dependent Btk activation. In a reconstitution cell system, coexpression of BLNK allows Syk to phosphorylate Btk on its tyrosine 551, leading to the enhancement of Btk activity. This phosphorylation depends on the interaction of Btk and BLNK by means of the Btk-Src homology 2 domain. The existence of such an activation mechanism is supported by the observation that the BCR-induced Btk phosphorylation and activation are significantly reduced in BLNK-deficient B cells as well as in Syk-deficient B cells. Although previous observations have identified the function of BLNK as the linker that integrates the action of Btk and Syk into downstream effectors such as phospholipase Cgamma2, our present study indicates another function of BLNK that connects the activity of Syk to that of Btk.
Proceedings of the National Academy of Sciences 03/2001; 98(5):2582-6. · 9.81 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: We have established a new line of immortalized rat astrocytes through transfection of plasmid pSV3-neo encoding the large T antigen of simian virus 40 into normal astrocytes. One of these immortalized astrocytes (ACT-57) with a flat and polygonal cell shape, exhibited stable growth in a chemically defined medium (modified N-2 medium) as well as in medium containing ordinary serum. ACT-57, retained a detectable level of expression of glial fibrillary acidic protein (GFAP) and its mRNA, and exhibited a stronger expression of nerve growth factor (NGF) mRNA than that of normal rat astrocytes or C6 glioma cells. NGF mRNA was significantly up-regulated by phorbol ester (12-O-tetradecanoylphorbol 13-acetate, TPA) and gamma-amino-n-butyric acid (GABA) but not by hydrocortisone. None of stimulants (TPA, dibutyryl cyclic AMP (db-cAMP), hydrocortisone, L-glutamate, carbacol, GABA, dopamine, or isoproterenol) changed the expression level of either brain-derived neurotrophic factor (BDNF) or neurotrophin-3 (NT-3). There was a discrete difference between ACT-57 and normal astrocytes in the response to GABA and isoproterenol. These findings imply that normal cortical astrocytes possess a functional heterogeneity whereas the clonal astrocyte, ACT-57, does not, indicating that ACT-57 cells may be useful for in vitro studies of neuron-astrocyte interactions involving the induction of neurotrophic factors such as NGF.
Neuroscience Research 03/2001; 39(2):205-12. · 2.20 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Signal transducer and activator of transcription (STAT)-induced STAT inhibitor 1 (SSI-1) is known to function as a negative feedback regulator of cytokine signaling, but it is unclear whether it is involved in other biological events. Here, we show that SSI-1 participates and plays an important role in the insulin signal transduction pathway. SSI-1-deficient mice showed a significantly low level of blood sugar. While the forced expression of SSI-1 reduced the phosphorylation level of insulin receptor substrate 1 (IRS-1), SSI-1 deficiency resulted in sustained phosphorylation of IRS-1 in response to insulin.Furthermore, SSI-1 achieves this inhibition both by binding directly to IRS-1 and by suppressing Janus kinases. These findings suggest that SSI-1 acts as a negative feedback factor also in the insulin signal transduction pathway through the suppression of IRS-1 phosphorylation.
Journal of Experimental Medicine 02/2001; 193(2):263-9. · 13.21 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Although a mass screening urinalysis is a widely accepted procedure, it has not yet been shown if microhematuria is an appropriate and useful screening marker for urologic malignancies.
(1) The incidence of hematuria was studied in 113 patients with renal cell carcinoma (RCC), 185 with bladder carcinoma and 51 with renal pelvic or ureteral carcinoma. The association of the T stage with the intensity of hematuria in each malignancy was also examined. (2) In 823 asymptomatic adults with microhematuria, the prevalence of these malignancies was studied retrospectively to find the positive predictive value (PPV).
(1) The incidence of hematuria was 35% for RCC, including gross and microhematuria. Advanced RCC (T3 and T4) were diagnosed more frequently in the gross hematuria group than in the microhematuria and no hematuria groups. In contrast, the incidence of hematuria was 94% for urothelial carcinomas either in the upper urinary tract or in the bladder. There was no significant difference in the T stage nor grade between the gross hematuria group and the microhematuria group. (2) Regarding asymptomatic microhematuria, the PPV was 1.7% (14 cases) for bladder carcinoma, 0.4% (3 cases) for ureteral/renal pelvic carcinoma and 0.2% (2 cases) for RCC. In men aged 50 years or older, PPV was 6.2% for urothelial carcinomas. In 14 cases of bladder carcinoma, 3 cases showed muscle invasion.
Microhematuria is an appropriate screening marker for urothelial carcinomas, particularly in elderly men, but not for RCC. However, it is unlikely that a mass screening urinalysis using a single voided urine sample would contribute to earlier detection of bladder carcinoma.
International Journal of Urology 02/2001; 8(1):1-5. · 1.73 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The role of PKN, a fatty acid- and Rho small GTPase-activated protein kinase, in cell-cycle regulation was analyzed. Microinjection of the active form of PKN into a Xenopus embryo caused cleavage arrest, whereas normal cell division proceeded in the control embryo microinjected with buffer or the inactive form of PKN. Exogenous addition of the active form of PKN delayed mitotic timing in Xenopus egg cycling extracts judging by morphology of sperm nuclei and Cdc2/cyclin B histone H1 kinase activity. The kinase-negative form of PKN did not affect the timing, suggesting that delayed mitotic timing depends on the kinase activity of PKN. The dephosphorylation of Tyr-15 of Cdc2 was also delayed in correlation with Cdc2/cyclin B histone H1 kinase activation in extracts containing active PKN. The Cdc25C activity for the dephosphorylation of Tyr-15 in Cdc2 was suppressed by pretreatment with the active form of PKN. Furthermore, PKN efficiently phosphorylated Cdc25C in vitro, indicating that PKN directly inhibits Cdc25C activity by phosphorylation. These results suggest that PKN plays a significant role in the control of mitotic timing by inhibition of Cdc25C.
Proceedings of the National Academy of Sciences 02/2001; 98(1):125-9. · 9.81 Impact Factor