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1.  Induction of AhR-Mediated Gene Transcription by Coffee 
PLoS ONE  2014;9(7):e102152.
Aryl hydrocarbon receptor (AhR) is classically known to be activated by xenobiotics such as dioxins and polycyclic aromatic hydrocarbons (PAHs). Although it has been reported that PAHs are contained in roasted coffee beans, in general coffee beverages are not considered to be AhR activators. We tested whether exposure to coffee would activate AhR in cultured cells.
HepG2 cells stably expressing an AhR-responsive reporter gene were treated with coffee samples. Also, expression of CYP1A1, an endogenous AhR-responsive gene, was quantitated by RT-PCR and Western blotting in HepG2, Caco-2, and MCF-7 cells, after treatment with coffee. In order to obtain sensitive and reproducible results, all the experiments were performed with the cells placed in either phosphate-buffered saline (PBS) or pure serum, instead of routinely-used culture medium, whose intrinsic AhR-stimulating activity turned out to be so strong as to interfere with the analyses.
All the coffee samples tested robustly stimulated AhR-mediated transcription in the reporter gene assays. Of note, to what extent coffee and other AhR agonists activated AhR was different, depending on whether the experiments were done in PBS or serum. CYP1A1 mRNA was induced by coffee, in HepG2, Caco-2, and MCF-7 cells placed in either PBS or serum. CYP1A1 protein expression, which was not detected in these cells incubated in PBS, was also increased by coffee in cells placed in serum.
By using culture medium-free experimental settings, we have shown that coffee is a strong AhR activator. Our observation may help elucidate as-yet-unrecognized effects of coffee on human health.
PMCID: PMC4090196  PMID: 25007155
2.  Association of the c.385C>A (p.Pro129Thr) polymorphism of the fatty acid amide hydrolase gene with anorexia nervosa in the Japanese population 
The functional c.385C>A single-nucleotide polymorphism (SNP) in the fatty acid amide hydrolase (FAAH) gene, one of the major degrading enzymes of endocannabinoids, is reportedly associated with anorexia nervosa (AN). We genotyped the c.385C>A SNP (rs324420) in 762 lifetime AN and 605 control participants in Japan. There were significant differences in the genotype and allele frequencies of c.385C>A between the AN and control groups. The minor 385A allele was less frequent in the AN participants than in the controls (allele-wise, odds ratio = 0.799, 95% confidence interval [CI] 0.653–0.976, P = 0.028). When the cases were subdivided into lifetime restricting subtype AN and AN with a history of binge eating or purging, only the restricting AN group exhibited a significant association (allele-wise, odds ratio = 0.717, 95% CI 0.557–0.922, P = 0.0094). Our results suggest that having the minor 385A allele of the FAAH gene may be protective against AN, especially restricting AN. This finding supports the possible role of the endocannabinoid system in susceptibility to AN.
PMCID: PMC4113271  PMID: 25077173
Anandamide; cannabinoid 1 receptor; eating disorder; endocannabinoid
3.  Psychological and weight-related characteristics of patients with anorexia nervosa-restricting type who later develop bulimia nervosa 
Patients with anorexia nervosa-restricting type (AN-R) sometimes develop accompanying bulimic symptoms or the full syndrome of bulimia nervosa (BN). If clinicians could predict who might change into the bulimic sub-type or BN, preventative steps could be taken. Therefore, we investigated anthropometric and psychological factors possibly associated with such changes.
All participants were from a study by the Japanese Genetic Research Group for Eating Disorders. Of 80 patients initially diagnosed with AN-R, 22 changed to the AN-Binge Eating/Purging Type (AN-BP) and 14 to BN for some period of time. The remaining 44 patients remained AN-R only from the onset to the investigation period. Variables compared by ANOVA included anthropometric measures, personality traits such as Multiple Perfectionism Scale scores and Temperament and Character Inventory scores, and Beck Depression Inventory-II scores.
In comparison with AN-R only patients, those who developed BN had significantly higher current BMI (p < 0.05) and maximum BMI in the past (p < 0.05). They also scored significantly higher for the psychological characteristic of parental criticism (p < 0.05) and lower in self-directedness (p < 0.05), which confirms previous reports, but these differences disappeared when the depression score was used as a co-variant. No significant differences were obtained for personality traits or depression among the AN-R only patients irrespective of their duration of illness.
The present findings suggest a tendency toward obesity among patients who cross over from AN-R to BN. Low self-directedness and high parental criticism may be associated with the development of BN by patients with AN-R, although the differences may also be associated with depression.
PMCID: PMC2275291  PMID: 18267038
4.  Age and gender effect on alexithymia in large, Japanese community and clinical samples: a cross-validation study of the Toronto Alexithymia Scale (TAS-20) 
The construct validity of alexithymia and its assessment using the 20-item Toronto Alexithymia Scale (TAS-20) in Japan is unknown. Low reliability has been found for the third factor of the TAS-20 in some cultures, and the factor structure for psychosomatic disorder patients has not been adequately investigated. Although alexithymia most likely has certain developmental aspects, this has infrequently been investigated.
The newly-developed Japanese TAS-20 was administered to a normative sample (n = 2,718; 14–84 y.o.), along with the NEO Five-Factor Inventory (NEO-FFI) for cross validation. Psychosomatic patients (n = 1,924, 12–87 y.o.) were tested to evaluate the factor structure in a clinical sample. College students (n = 196) were used for a test-retest study. Internal reliability and consistency were assessed, and the factorial structure was evaluated using confirmatory and exploratory factor analyses for both the normative and the clinical samples. The correlations between the TAS-20 and the NEO-FFI factor scores were evaluated. Age-related and gender differences in the TAS-20 were explored using analysis of variance in the normative sample.
The original three-factor model of the TAS-20 was confirmed to be valid for these Japanese samples, although a 4-factor solution that included negatively keyed items (NKI) as an additional factor was more effective. Significant correlations of the TAS-20 with the NEO-FFI were found, as has been previously reported. Factor analyses of the normative and patient samples showed similar patterns. The TAS-20 total, difficulty in identifying feelings (DIF), and difficulty in describing feelings (DDF) scores were high for teenagers, decreased with age, and from 30s did not change significantly. In contrast, externally oriented thinking (EOT) scores showed an almost linear positive correlation with age. DIF scores were higher for females, while EOT scores were higher for males, without any interaction between gender and age differences.
The original three-factor concept of the TAS-20 was generally supported for practical use. Age-related differences in TAS-20 scores indicate developmental aspects of alexithymia. Alexithymia is made up of two components with different developmental paths: DIF/DDF and EOT.
PMCID: PMC1838425  PMID: 17371586
5.  Nonhomologous End-Joining Ligation Transfers DNA Regulatory Elements between Cointroduced Plasmids 
Molecular and Cellular Biology  2004;24(19):8323-8331.
Cointroduction of plasmids into mammalian cells is commonly used to investigate transcription factor regulation of reporter genes or to normalize transfection efficiency. We report here that cotransfected DNA molecules commonly transfer enhancer elements from one plasmid to another. Using separate Renilla or Firefly luciferase reporters, we found that an estrogen response element (ERE) originally linked to one of the reporters stimulated expression of the non-ERE-containing reporter. Similar enhancer transfer was seen with the cytomegalovirus enhancer. This enhancer transfer effect was not seen when cells were transfected separately with the reporters and the extracts were then combined before luciferase assays. The degree of enhancer transfer increased with transfected plasmid concentration and was greater when linearized rather than circular plasmid DNA was used. We hypothesized that double-strand breaks and heteroligation of cointroduced DNA molecules mediated the transfer of regulatory elements from one molecule to another. PCR of transfected plasmid DNA confirmed nonhomologous end-joining (NHEJ) ligation of DNA fragments originally present in separate plasmids. The NHEJ reaction was enhanced by UV light treatment to introduce double-strand breaks, and it was greater after liposome-mediated transfection than after calcium-phosphate-mediated transfection. NHEJ also occurred after adenoviral transfer of DNA into cells. We conclude that NHEJ mediates the transfer of regulatory DNA elements among cointroduced DNA molecules. These findings indicate the need for caution when interpreting results of transfection experiments containing more than one plasmid and suggest a mechanism whereby viruses or other exogenous DNA might recombine to activate unrelated genes.
PMCID: PMC516743  PMID: 15367654
6.  Cysteine Protease Activity and Histamine Release from the Human Mast Cell Line HMC-1 Stimulated by Recombinant Streptococcal Pyrogenic Exotoxin B/Streptococcal Cysteine Protease  
Infection and Immunity  2002;70(7):3944-3947.
We constructed the expression vector pSK-SCP containing the streptococcal exotoxin B gene (spe b) which expressed protease activity. We showed that the recombinant streptococcal pyogenic exotoxin B/streptococcal cysteine protease (rSPE B/SCP) was secreted into the culture supernatant of the transformant and retained its SCP activity, which was equivalent to or greater than that of the naturally occurring molecule. The secreted rSPE B/SCP induced histamine release and degranulation of the human mast cell line HMC-1. This study may contribute to the understanding of the pathogenic role of SPE B/SCP in streptococcal infection and streptococcal toxic shock syndrome.
PMCID: PMC128063  PMID: 12065540

Results 1-6 (6)