BackgroundObesity has become one of the most serious social problems in developed countries, including Japan. The relationship between the gut microbiota and obesity has recently attracted the attention of many researchers. Although the gut microbiota was long thought to contribute to obesity, the exact association remains largely unknown. We examined the human gut microbiota composition in a Japanese population in order to determine its relationship to obesity.MethodsStool samples from 23 non-obese subjects (body mass index [BMI] <20 kg/m2) and 33 obese subjects (BMI ≥25 kg/m2) were collected and DNA was extracted prior to colonoscopy. After terminal restriction fragment length polymorphism (T-RFLP) analysis, samples from 10 subjects (4 non-obese and 6 obese) were selected and subjected to next-generation sequencing for species-level analysis.ResultsT-RFLP analysis showed significantly reduced numbers of Bacteroidetes and a higher Firmicutes to Bacteroidetes ratio in obese subjects compared with non-obese subjects. Bacterial diversity was significantly greater in obese subjects compared with non-obese subjects. Next-generation sequencing revealed that obese and non-obese subjects had different gut microbiota compositions and that certain bacterial species were significantly associated with each group (obese: Blautia hydrogenotorophica, Coprococcus catus, Eubacterium ventriosum, Ruminococcus bromii, Ruminococcus obeum; non-obese: Bacteroides faecichinchillae, Bacteroides thetaiotaomicron, Blautia wexlerae, Clostridium bolteae, Flavonifractor plautii).ConclusionGut microbial properties differ between obese and non-obese subjects in Japan, suggesting that gut microbiota composition is related to obesity.Electronic supplementary materialThe online version of this article (doi:10.1186/s12876-015-0330-2) contains supplementary material, which is available to authorized users.

Survivin is a recently described inhibitor of apoptosis. Because suppression of apoptosis is important for carcinogenesis and tumor growth, we investigated the expression and function of survivin in human hepatocellular carcinomas (HCCs). We have shown that 4 HCC cell lines and 7 out of 8 human HCC tissues expressed survivin messenger RNA (mRNA), whereas expression of survivin mRNA was not detected in normal liver and nontumor areas of these tissues using the reverse transcription polymerase chain reaction. Survivin was detected primarily in the nucleus by immunofluorescence staining of HCC cells. In addition, 14 of 20 (70%) HCC tissues showed positive nuclear staining for survivin, whereas nontumor tissues showed little detectable staining by immunohistochemistry. Survivin expression strongly correlated with the proliferation index but not significantly with the apoptosis index in HCC tissues. Therefore, we performed cell cycle analysis after survivin transfection and showed that overexpression of survivin resulted in a decrease in the G 0 /G 1 phase and an increase in the S phase in all 4 HCC cell lines. Furthermore, we have found that survivin interacted with cyclin-dependent kinase 4 (Cdk4) and overexpression of survivin released p21 WAF1/Cip1 (p21) from Cdk4. From these results, we conclude that survivin promotes cell proliferation by interacting with Cdk4 and releasing p21 from Cdk4. This may play an important role in carcinogenesis and progression of human HCCs. (HEPA-TOLOGY 2000;31:1080-1085.)Regulation of programmed cell death is important in the preservation of homeostasis and morphogenesis of human tissues. 1,2 Impairment of apoptosis facilitates the accumulation of gene mutations by prolonging the cell cycle span and promoting resistance to immune-based cytotoxicity, 3 finally contributing to carcinogenesis. 4 It has been shown recently that the inhibitors of apoptosis proteins (IAP) are crucial regulators in the molecular mechanism of apoptosis. [5][6][7] Among the IAP members, survivin is unique in that it is undetectable in normal adult tissue, but abundantly expressed in transformed cells and a variety of human cancers. 8 It has also been shown that survivin inhibits apoptosis in cells exposed to diverse apoptotic stimuli 8-11 by associating with microtubules of the mitotic spindle 9 and inhibiting caspase activity. 10 Expression of survivin is highly correlated with prognosis in patients with neuroblastoma, 7,12 gastric cancer, 13 colorectal cancer, 14 and bladder cancers. 15 However, the biological functions of survivin, other than its antiapoptotic effect, are not well understood in human cancers.Therefore, to gain insight into additional roles of survivin in malignant cells, we investigated the expression and function of survivin in hepatocellular carcinoma (HCC) cell lines and human HCC. In this study, we showed that survivin expression correlates with HCC cell proliferation in the majority of human HCC tissues. Survivin overexpression obliterates the G 1 checkpoint by releasing p21 WAF1/Cip...

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This study was performed to examine the immunologic basis for the apparent ethnic difference in clinical outcome of hepatitis C virus (HCV) infection between African Americans (AA) and Caucasian Americans (CA). To this end, we recruited 99 chronically HCV-infected and 31 spontaneously HCV-cleared subjects for clinical, virologic, and immunologic analysis. In particular, CD4-proliferative T-cell response to genotype 1-derived HCV antigens (core, NS3-NS5) was examined in 82 patients chronically infected with genotype 1 (54 AA, 28 CA) and in all HCV-cleared subjects (14 AA, 17 CA). HCV-specific Th1 response also was examined in 52 chronic and 13 recovered subjects. Our results showed that HCV clearance was associated with a vigorous HCV-specific Th1 response irrespective of ethnic origin. Although the HCV-specific CD4 T-cell response clearly was weaker during chronic infection, AA ethnicity in this setting was associated with a significantly greater CD4-proliferative T-cell response to HCV, particularly to the nonstructural antigens (22% AA vs. 0% CA, P ‫؍‬ .007) as well as better clinical parameters of liver disease. Interestingly, most HCV-specific CD4 T-cell proliferative responses in AA patients were unaccompanied by concurrent interferon ␥ (IFN-␥) production, suggesting a dysregulated virus-specific, CD4 T-cell effector function during chronic HCV infection. In conclusion, our results suggest that host ethnicity does influence the clinical outcome and antiviral T-cell response during HCV infection. AA ethnicity is associated with a more robust antiviral CD4 T-cell response than CA ethnicity, although these T cells are limited in direct virus or disease control due to their dysfunctional nature. (HEPATOLOGY 2003;37:590-599.)

Senescent cells accumulate in many tissues as animals age and are considered to underlie several aging-associated pathologies. The tumor suppressors p19 and p16, both of which are encoded in the locus, play critical roles in inducing and maintaining permanent cell cycle arrest during cellular senescence. Although the elimination of p16-expressing cells extends the life span of the mouse, it is unclear whether tissue function is restored by the elimination of senescent cells in aged animals and whether and how p19 contributes to tissue aging. The aging-associated decline in lung function is characterized by an increase in compliance as well as pathogenic susceptibility to pulmonary diseases. We herein demonstrated that pulmonary function in 12-month-old mice was reversibly restored by the elimination of p19-expressing cells. The ablation of p19-expressing cells using a toxin receptor-mediated cell knockout system ameliorated aging-associated lung hypofunction. Furthermore, the aging-associated gene expression profile was reversed after the elimination of p19. Our results indicate that the aging-associated decline in lung function was, at least partly, attributed to p19 and was recovered by eliminating p19-expressing cells.