Aiko Yamauchi

Regional distribution and characterization of kinin in the CNS of the rat.

The distribution of kinin in the CNS of the rat, which was extracted with n‐butanol from an acidified homogenate, was determined using a bradykinin (BK) radioimmunoassay system. The immunoreactive kinin was widely distributed throughout the brain. The highest content was found in the pituitary gland (4,135 fmol BK Eq/g), followed by the medulla oblongata (912 fmol/g), cerebellum (549 fmol/g), and cortex (512 fmol/g). The kinin in the posterior pituitary was concentrated 4.5 times as much as in the anterior lobe. Serial dilution of brain extracts produced binding curves parallel to the standard radioimmunoassay curve. The purified brain kinin comigrated with authentic BK during CM‐cellulose chroma tography and Sephadex LH‐20 gel chromatography. Its molecular weight was estimated to be 1,127

Involvement of histone hyperacetylation in triggering DNA fragmentation of rat thymocytes undergoing apoptosis

45 by gel filtration, which coincides well with that of BK. Chymotrypsin degraded the extracted kinin and authentic BK, but trypsin did not. These data demonstrate that a peptide indistinguishable from BK exists in the rat brain. Furthermore, pituitary kinin was separated into BK (87%), Lys‐BK (10%), and Met‐Lys‐BK (3%), using reverse phase HPLC.

The disappearance rate of intraventricular bradykinin in the brain of the conscious rat.

The treatment of rat thymocytes with trichostatin A and sodium butyrate, which are inhibitors of histone deacetylase, resulted in an increase in DNA fragmentation in a concentration‐dependent manner. A significant increase in DNA fragmentation induced by these compounds was observed after a lag time of 2 h. Analysis of the fragmented DNA revealed the production of approximately 50 kb DNA fragments and DNA ladders, the biochemical hallmarks of apoptotic cell death. Judging from a laser scanning microscopic analysis, the inhibitors of histone deacetylase induced nuclear condensation, the morphological feature of apoptosis. Biochemical and morphological analyses demonstrated that trichostatin A and sodium butyrate induced thymocyte apoptosis. Furthermore, hyperacetylation of nuclear histones was observed in thymocytes treated with the inhibitors of histone deacetylase. These effects of sodium butyrate and trichostatin A were seen 0.5 and 1 h, respectively, after incubation of the cells. These results thus indicate that hyperacetylation of nucleosomal histones precedes DNA fragmentation in thymocytes undergoing apoptosis induced by trichostatin A and sodium butyrate.

Inhibitory effects of a cyclosporin derivative, SDZ PSC 833, on transport of doxorubicin and vinblastine via human P-glycoprotein

Summary The disappearance rate of bradykinin injected intraventricularly was investigated in the conscious rat. Microwave irradiation (4.5 kW, 2 sec) produced rapid inactivation of the brain kinin-degrading activity. Using specific bradykinin-radioimmunoassay, the biological half-time of bradykinin (5 nmol) in the brain was determined to be 26.6 ± 3.6 sec after the intraventricular administration. o-Phenanthroline, SQ 14225 and bradykinin potentiator B used for pretreatment intraventricularly, are kininase inhibitors, that prolonged the fate of bradykinin in a dose dependent manner.

Relationship between central actions of bradykinin and prostaglandins in the conscious rat.

The inhibitory effects of SDZ PSC 833 (PSC833), a non‐immunosuppressive cyclosporin derivative, on the P‐glycoprotein (P‐gp)‐mediated transport of doxorubicin and vinblastine were compared with those of cyclosporin A (Cs‐A). The transcellular transport of the anticancer drugs and PSC833 across a monolayer of LLC‐GA5‐COL150 cells, which overexpress human P‐gp, was measured. Both PSC833 and Cs‐A inhibited P‐gp‐mediated transport of doxorubicin and vinblastine in a concentration‐dependent manner and increased the intracellular accumulation of doxorubicin and vinblastine in LLC‐GA5‐COL150 cells. The values of the 50%‐inhibitory concentration (IC50) of PSC833 and Cs‐A for doxorubicin transport were 0.29 and 3.66 μM, respectively, and those for vinblastine transport were 1.06 and 5.10 μM, respectively. The IC50 of PSC833 for doxorubicin transport was about 4‐fold less than that for vinblastine transport, suggesting that the combination of PSC833 and doxorubicin might be effective. PSC833 itself was not transported by P‐gp and had higher lipophilicity than Cs‐A. These results indicated that the inhibitory effect of PSC833 on P‐gp‐mediated transport was 5‐ to 10‐fold more potent than that of Cs‐A, and this higher inhibitory effect of PSC833 may be related to the absence of PSC833 transport by P‐gp and to the higher lipophilicity of PSC833.

Tissue distribution of and species differences in deacetylation of N-acetyl-L-cysteine and immunohistochemical localization of acylase I in the primate kidney

Intraventricular injection of bradykinin produced a dose-dependent increase in the mean arterial blood pressure of conscious rats. With 5 nmol of bradykinin, a dual pressor response was observed, which was associated with a biphasic behavioral change. With repeated hourly injections of bradykinin, tachyphylaxis developed to the pressor and central nervous system (CNS) stimulating effect. Indomethacin, given intraventricularly, reduced the hypertension and the behavioral excitation caused by bradykinin in a dose-dependent manner. When prostaglandin E2 was injected into the cerebral ventricles, it induced hypertension and behavioral sedation similar to the secondary response to bradykinin. These results suggest that bradykinin has a dual action on the CNS, and this is mediated by prostaglandin-related systems in the brain.

Involvement of histone phosphorylation in apoptosis of human astrocytes after exposure to saline solution.

Species differences in the biotransformation of N‐acetyl‐L‐cysteine (NAC) have been investigated to evaluate the usefulness of NAC as a constituent in parenteral nutrition solutions in place of cysteine. The activity of NAC‐deacetylating enzyme (acylase) was measured in various tissues of different species (rat, rabbit, dog, monkey, and man). Acylase activity was highest in the kidney in all species studied. Enzyme activity in the liver was 10%‐22% of that in the kidney in the rat, rabbit, monkey, and man, but almost no hepatic activity was seen in the dog. NAC‐deacetylating activity was very low in other organs. The tissue distribution of acylase I was determined by Western blotting and an immunohistochemical method employing specific antibody against porcine acylase I (EC 3.5.1.14). The immunoblotting study showed a 46‐kDa protein band corresponding to porcine acylase I in the kidney of all species. In liver cytosol, 46 kDa and/or 29 kDa bands were observed in the rat, rabbit, monkey, and man, but not in the dog. In the immunohistochemical study, positive staining with anti‐acylase I antibody was observed clearly in the renal proximal tubules in the monkey and man. These results suggested that the kidney and liver were the main organs responsible for the biotransformation of NAC to cysteine in mammals other than the dog.

An association study of four candidate loci for human male fertility traits with male infertility

We have previously found using inhibitors of protein phosphatase that phosphorylation of histones may be involved in thymocyte apoptosis. In this study, we examined whether histone modification occurs in astrocyte apoptosis induced by a pathological condition in the absence of drug. Incubation of cultured human astrocytes with growth medium for 24 h after exposure to saline solution for 30 min induced an increase in terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL)-positive cells and nuclear condensation, biochemical and morphological hallmarks of apoptotic cell death. Acetic acid-urea-Triton X-100 (AUT) gel electrophoresis of the nuclear histone fraction and N-terminal peptide analysis showed that the treatment with saline solution caused rapid changes in phosphorylation of H2A subfamilies, but not in histone acetylation. The phosphorylation of the two subtypes increased markedly, whereas the phosphorylation of one subtype decreased. In contrast, exposure to ACF-95, an artificial cerebrospinal fluid (CSF), was associated with little induction of apoptotic cell death and induced less changes in histone phosphorylation. These results support the previous idea that chemical modification of histones is involved in the DNA fragmentation in astrocytes undergoing apoptosis.

Involvement of Histone Phosphorylation in Thymocyte Apoptosis by Protein Phosphatase Inhibitors

STUDY QUESTION Are the four candidate loci (rs7867029, rs7174015, rs12870438 and rs724078) for human male fertility traits, identified in a genome-wide association study (GWAS) of a Hutterite population in the USA, associated with male infertility in a Japanese population? SUMMARY ANSWER rs7867029, rs7174015 and rs12870438 are significantly associated with the risk of male infertility in a Japanese population. WHAT IS KNOWN ALREADY Recently, a GWAS of a Hutterite population in the USA revealed that 41 single-nucleotide polymorphisms (SNPs) were significantly correlated with family size or birth rate. Of these, four SNPs (rs7867029, rs7174015, rs12870438 and rs724078) were found to be associated with semen parameters in ethnically diverse men from Chicago. STUDY DESIGN, SIZE, DURATION This is a case-control association study in a total of 917 Japanese subjects, including 791 fertile men, 76 patients with azoospermia and 50 patients with oligozoospermia. PARTICIPANTS/MATERIALS, SETTING, METHODS Azoospermia was diagnosed on the basis of semen analysis (the absence of sperm in ejaculate), serum hormone levels and physical examinations. Oligozoospermia was defined as a sperm concentration of <20 × 10(6)/ml. We excluded patients with any known cause of infertility (i.e. obstructive azoospermia, varicocele, cryptorchidism, hypogonadotropic hypogonadism, karyotype abnormalities or complete deletion of AZF a, b or c). The SNPs rs7867029, rs7174015, rs12870438 and rs724078 were genotyped using DNA from peripheral blood samples and either restriction fragment length polymorphism PCR or TaqMan probes. Genetic associations between the four SNPs and male infertility were assessed using a logistic regression analysis under three different comparative models (additive, recessive or dominant). MAIN RESULTS AND THE ROLE OF CHANCE The genotypes of all four SNPs were in Hardy-Weinberg equilibrium in the fertile controls. The SNPs rs7867029 and rs7174015 are associated with oligozoospermia [rs7867029: odds ratio (OR) = 1.70, 95% confidence interval (CI) = 1.07-2.68, P = 0.024 (log-additive); rs7174015: OR = 6.52, 95% CI = 1.57-27.10, P = 0.0099 (dominant)] and rs12870438 is associated with azoospermia (OR = 10.90, 95% CI = 2.67-44.60, P = 0.00087 (recessive)] and oligozoospermia [OR = 8.54, 95% CI = 1.52-47.90, P = 0.015 (recessive)]. The association between rs7174015 and oligozoospermia under a dominant model and between rs12870438 and azoospermia under additive and recessive models remained after correction for multiple testing. There were no associations between rs724078 and azoospermia or oligozoospermia. LIMITATIONS, REASONS FOR CAUTION Even though the sample size of case subjects was not very large, we found that three SNPs were associated with the risk of male infertility in a Japanese population. WIDER IMPLICATIONS OF THE FINDINGS The three infertility-associated SNPs may be contributing to a quantitative reduction in spermatogenesis. STUDY FUNDING/COMPETING INTERESTS This study was supported in part by the Ministry of Health and Welfare of Japan (1013201) (to T.I.), Grant-in-Aids for Scientific Research (C) (23510242) (to A.Ta.) from the Japan Society for the Promotion of Science, the European Union (BMH4-CT96-0314) (to T. I.) and the Takeda Science Foundation (to A.Ta.). None of the authors has any competing interests to declare.

Replication Study and Meta-Analysis of Human Nonobstructive Azoospermia in Japanese Populations

Incubation of rat thymocytes with the inhibitors of protein phosphatase such as calyculin A and okadaic acid resulted in an increase in DNA fragmentation. These effects were dependent on the concentration of the inhibitors and the incubation time. Analyses of the fragmented DNA revealed the production of 50 kbp of DNA and a 180 bp DNA ladder. In addition, a laser scanning microscopic analysis showed that these compounds caused nuclear condensation. Thus, these results demonstrated that protein phosphatase inhibitors induced thymocyte apoptosis. The inhibitors of protein phosphatase increased the phosphorylation of proteins of 15 kDa. The phosphorylation of proteins preceded the DNA fragmentation induced by these inhibitors. Judging from acetic acid urea Triton X‐100 gel electrophoresis, the phosphorylated proteins were histone H1 and H2A/H3. Therefore, these results suggest that phosphorylation of histones triggers the DNA fragmentation of thymocytes undergoing apoptosis.