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...

Fas ligand (FasL) plays a pivotal role in lymphocyte cytotoxicity and the maintenance of immunological homeostasis. Since FasL has been implicated in the existence of immunologically privileged body sites by inducing apoptosis of activated T lymphocytes, we investigated the expression of FasL in human colon cancers. We found that two out of seven primary tumors and all four hepatic metastatic tumors of surgically obtained colonic adenocarcinoma expressed FasL mRNA and protein, detected by reverse transcription-coupled PCR and by immunohistochemical staining, respectively. Expression of FasL was not detected in normal colonic epithelial cells. FasL mRNA was also expressed in some human colonic adenocarcinoma cell lines including SW480, SW1116, and LS180 cells. Cell-surfaceassociated FasL was detected in these human colon cancer cells by f luorescence immunocytochemical staining. In addition, the expressed FasL was demonstrated to be functional, since coculture experiments using FasL-expressing SW480 cells resulted in apoptosis of Jurkat T leukemia cells that are sensitive to Fas-mediated apoptosis, and this process was specifically inhibited by the neutralizing anti-human FasL antibody. Thus, our findings and other data suggest an alternative mechanism that enables tumors to evade immune destruction by inducing apoptosis in activated T lymphocytes. Furthermore, constitutive expression of FasL in hepatic metastatic tumors suggests that FasL may also be important in their colonization in the liver through induction of apoptosis in the surrounding Fas-expressing hepatocytes.

Phosphorylation of CPI-17 by Rho-associated kinase (Rho-kinase) and its effect on myosin phosphatase (MP) activity were investigated. CPI-17 was phosphorylated by Rho-kinase to 0.92 mol of P/mol of CPI-17 in vitro. The inhibitory phosphorylation site was Thr 38 (as reported previously) and was identified using a point mutant of CPI-17 and a phosphorylation state-specific antibody. Phosphorylation by Rho-kinase dramatically increased the inhibitory effect of CPI-17 on MP activity. Thus, CPI-17 as a substrate of Rho-kinase could be involved in the Ca 2 sensitization of smooth muscle contraction as a downstream effector of Rho-kinase. ß