52 research outputs found

    Spontaneous parity and charge-conjugation violations at real isospin and imaginary baryon chemical potentials

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    The phase structure of two-flavor QCD is investigated at real isospin and imaginary quark chemical potentials by using the Polyakov-loop extended Nambu--Jona-Lasinio model. In the region, parity symmetry is spontaneously broken by the pion superfluidity phase transition, whereas charge-conjugation symmetry is spontaneously violated by the Roberge-Weiss transition. The chiral (deconfinement) crossover at zero isospin and quark chemical potentials is a remnant of the parity (charge-conjugation) violation. The interplay between the parity and charge-conjugation violations are analyzed, and it is investigated how the interplay is related to the correlation between the chiral and deconfinement crossovers at zero isospin and quark chemical potentials.Comment: 12 pages, 18 figures. Typos were revised. Symbols /P and /C were added in Figures 8a and 8b. Colors of the figures were changed. Some sentences were added and revise

    Interaction between lung cancer cells and astrocytes via specific inflammatory cytokines in the microenvironment of brain metastasis

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    The incidence of brain metastasis is increasing, however, little is known about molecular mechanism responsible for lung cancer-derived brain metastasis and their development in the brain. In the present study, brain pathology was examined in an experimental model system of brain metastasis as well as in human brain with lung cancer metastasis. In an experimental model, after 3–6 weeks of intracardiac inoculation of human lung cancer-derived (HARA-B) cells in nude mice, wide range of brain metastases were observed. The brain sections showed significant increase in glial fibrillary acidic protein (GFAP)-positive astrocytes around metastatic lesions. To elucidate the role of astrocytes in lung cancer proliferation, the interaction between primary cultured mouse astrocytes and HARA-B cells was analyzed in vitro. Co-cultures and insert-cultures demonstrated that astrocytes were activated by tumor cell-oriented factors; macrophage migration inhibitory factor (MIF), interleukin-8 (IL-8) and plasminogen activator inhibitor-1 (PAI-1). Activated astrocytes produced interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α) and interleukin-1 β (IL-1β), which in turn promoted tumor cell proliferation. Semi-quantitative immunocytochemistry showed that increased expression of receptors for IL-6 and its subunits gp130 on HARA-B cells. Receptors for TNF-α and IL-1β were also detected on HARA-B cells but down-regulated after co-culture with astrocytes. Insert-culture with astrocytes also stimulated the proliferation of other lung cancer-derived cell lines (PC-9, QG56, and EBC-1). These results suggest that tumor cells and astrocytes stimulate each other and these mutual relationships may be important to understand how lung cancer cells metastasize and develop in the brain

    Downregulation of SAV1 plays a role in pathogenesis of high-grade clear cell renal cell carcinoma

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    <p>Abstract</p> <p>Background</p> <p>Clinical outcome of patients with high-grade ccRCC (clear cell renal cell carcinoma) remains still poor despite recent advances in treatment strategies. Molecular mechanism of pathogenesis in developing high-grade ccRCC must be clarified. In the present study, we found that SAV1 was significantly downregulated with copy number loss in high-grade ccRCCs. Therefore, we investigated the SAV1 function on cell proliferation and apoptosis in vitro. Furthermore, we attempted to clarify the downstream signaling which is regulated by SAV1.</p> <p>Methods</p> <p>We performed array CGH and gene expression analysis of 8 RCC cell lines (786-O, 769-P, KMRC-1, KMRC-2, KMRC-3, KMRC-20, TUHR4TKB, and Caki-2), and expression level of mRNA was confirmed by quantitative RT-PCR (qRT-PCR) analysis. We next re-expressed SAV1 in 786-O cells, and analyzed its colony-forming activity. Then, we transfected siRNAs of SAV1 into the kidney epithelial cell line HK2 and renal proximal tubule epithelial cells (RPTECs), and analyzed their proliferation and apoptosis. Furthermore, the activity of YAP1, which is a downstream molecule of SAV1, was evaluated by western blot analysis, reporter assay and immunohistochemical analysis.</p> <p>Results</p> <p>We found that SAV1, a component of the Hippo pathway, is frequently downregulated in high-grade ccRCC. SAV1 is located on chromosome 14q22.1, where copy number loss had been observed in 7 of 12 high-grade ccRCCs in our previous study, suggesting that gene copy number loss is responsible for the downregulation of SAV1. Colony-forming activity by 786-O cells, which show homozygous loss of SAV1, was significantly reduced when SAV1 was re-introduced exogenously. Knockdown of SAV1 promoted proliferation of HK2 and RPTEC. Although the phosphorylation level of YAP1 was low in 786-O cells, it was elevated in SAV1-transduced 786-O cells. Furthermore, the transcriptional activity of the YAP1 and TEAD3 complex was inhibited in SAV1-transduced 786-O cells. Immunohistochemistry frequently demonstrated nuclear localization of YAP1 in ccRCC cases with SAV1 downregulation, and it was preferentially detected in high-grade ccRCC.</p> <p>Conclusions</p> <p>Taken together, downregulation of SAV1 and the consequent YAP1 activation are involved in the pathogenesis of high-grade ccRCC. It is an attractive hypothesis that Hippo signaling could be candidates for new therapeutic target.</p

    Diminished Medial Prefrontal Activity behind Autistic Social Judgments of Incongruent Information

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    Individuals with autism spectrum disorders (ASD) tend to make inadequate social judgments, particularly when the nonverbal and verbal emotional expressions of other people are incongruent. Although previous behavioral studies have suggested that ASD individuals have difficulty in using nonverbal cues when presented with incongruent verbal-nonverbal information, the neural mechanisms underlying this symptom of ASD remain unclear. In the present functional magnetic resonance imaging study, we compared brain activity in 15 non-medicated adult males with high-functioning ASD to that of 17 age-, parental-background-, socioeconomic-, and intelligence-quotient-matched typically-developed (TD) male participants. Brain activity was measured while each participant made friend or foe judgments of realistic movies in which professional actors spoke with conflicting nonverbal facial expressions and voice prosody. We found that the ASD group made significantly less judgments primarily based on the nonverbal information than the TD group, and they exhibited significantly less brain activity in the right inferior frontal gyrus, bilateral anterior insula, anterior cingulate cortex/ventral medial prefrontal cortex (ACC/vmPFC), and dorsal medial prefrontal cortex (dmPFC) than the TD group. Among these five regions, the ACC/vmPFC and dmPFC were most involved in nonverbal-information-biased judgments in the TD group. Furthermore, the degree of decrease of the brain activity in these two brain regions predicted the severity of autistic communication deficits. The findings indicate that diminished activity in the ACC/vmPFC and dmPFC underlies the impaired abilities of individuals with ASD to use nonverbal content when making judgments regarding other people based on incongruent social information

    Matricellular Proteins Produced by Melanocytes and Melanomas: In Search for Functions

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    Matricellular proteins are modulators of cell-matrix interactions and cellular functions. The group includes thrombospondin, osteopontin, osteonectin/SPARC, tenascin, disintegrins, galectins and CCN proteins. The production of matricellular proteins such as osteopontin, SPARC or tenascin is highly upregulated in melanoma and other tumors but little is known about their functions in tumor growth, survival, and metastasis. The distribution pattern of CCN3 differs from most other matricellular proteins, such that it is produced abundantly by normal melanocytes, but is not significantly expressed in melanoma cells. CCN3 is known to inhibit melanocyte proliferation and stimulate adhesion to collagen type IV, the main component of the basement membrane. CCN3 has a unique role in securing adhesion of melanocytes to the basement membrane distinct from other melanoma-produced matricellular proteins which act as de-adhesive molecules and antagonists of focal adhesion. Qualitative and quantitative changes in matricellular protein expression contribute to melanoma progression similar to the E-cadherin to N-cadherin class switch, allowing melanoma cells to escape from keratinocyte control

    Polymorphisms of PTPN11 coding SHP-2 as biomarkers for ulcerative colitis susceptibility in the Japanese population.

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    OBJECTIVE: To identify genetic determinants of inflammatory bowel disease (IBD), we examined an association between polymorphisms of both the programmed cell death 1 gene (PDCD1) and the src homology 2 domain-containing tyrosine phosphatase 2 gene (PTPN11) and susceptibility to IBD. METHODS: Study subjects comprised 114 patients with ulcerative colitis (UC), 83 patients with Crohn\u27s disease, and 200 healthy control subjects. Five single nucleotide polymorphisms (SNPs) in PDCD1 and PTPN11 were detected by polymerase chain reaction restriction fragment length polymorphism. Subsequently, haplotypes composed of the two SNPs in PTPN11 were constructed. RESULTS: The frequencies of the Hap 1 haplotype and its homozygous Hap 1/Hap 1 diplotype of PTPN11 were significantly increased in UC patients compared to control subjects (P = 0.011 and P = 0.030, respectively). While no association was found for PDCD1 for UC or CD and none for PTPN11 for CD. CONCLUSION: PTPN11 is a genetic determinant for the pathogenesis of UC, and haplotyping of PTPN11 may be useful as a genetic biomarker to identify high-risk individuals susceptible to UC

    The Constrained Maximal Expression Level Owing to Haploidy Shapes Gene Content on the Mammalian X Chromosome.

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    X chromosomes are unusual in many regards, not least of which is their nonrandom gene content. The causes of this bias are commonly discussed in the context of sexual antagonism and the avoidance of activity in the male germline. Here, we examine the notion that, at least in some taxa, functionally biased gene content may more profoundly be shaped by limits imposed on gene expression owing to haploid expression of the X chromosome. Notably, if the X, as in primates, is transcribed at rates comparable to the ancestral rate (per promoter) prior to the X chromosome formation, then the X is not a tolerable environment for genes with very high maximal net levels of expression, owing to transcriptional traffic jams. We test this hypothesis using The Encyclopedia of DNA Elements (ENCODE) and data from the Functional Annotation of the Mammalian Genome (FANTOM5) project. As predicted, the maximal expression of human X-linked genes is much lower than that of genes on autosomes: on average, maximal expression is three times lower on the X chromosome than on autosomes. Similarly, autosome-to-X retroposition events are associated with lower maximal expression of retrogenes on the X than seen for X-to-autosome retrogenes on autosomes. Also as expected, X-linked genes have a lesser degree of increase in gene expression than autosomal ones (compared to the human/Chimpanzee common ancestor) if highly expressed, but not if lowly expressed. The traffic jam model also explains the known lower breadth of expression for genes on the X (and the Z of birds), as genes with broad expression are, on average, those with high maximal expression. As then further predicted, highly expressed tissue-specific genes are also rare on the X and broadly expressed genes on the X tend to be lowly expressed, both indicating that the trend is shaped by the maximal expression level not the breadth of expression per se. Importantly, a limit to the maximal expression level explains biased tissue of expression profiles of X-linked genes. Tissues whose tissue-specific genes are very highly expressed (e.g., secretory tissues, tissues abundant in structural proteins) are also tissues in which gene expression is relatively rare on the X chromosome. These trends cannot be fully accounted for in terms of alternative models of biased expression. In conclusion, the notion that it is hard for genes on the Therian X to be highly expressed, owing to transcriptional traffic jams, provides a simple yet robustly supported rationale of many peculiar features of X's gene content, gene expression, and evolution
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