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Articles by Y Liu
Total Records ( 40 ) for Y Liu
  F Guo , Y Li , Y Liu , J Wang and G. Li
 

Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) is suggested to be a long (~7 kb) non-coding RNA. MALAT1 is overexpressed in many human carcinomas, but its function remains unknown. To investigate the role of MALAT1 in human cervical cancer progression, we designed and used short hairpin RNA to inhibit MALAT1 expression in CaSki cells and validated its effect on cell proliferation and invasion. Changes in gene expression were analyzed by reverse transcriptase–polymerase chain reaction. Our data demonstrated that MALAT1 was involved in cervical cancer cell growth, cell cycle progression, and invasion through the regulation of gene expression, such as caspase-3, -8, Bax, Bcl-2, and Bcl-xL, suggesting that MALAT1 could have important implications in cervical cancer biology. Our findings illustrate the biological significance of MALAT1 in cervical cancer progression and provide novel evidence that MALAT1 may serve as a therapeutic target in the prevention of human cervical cancer.

  L Sun , X Shen , Y Liu , G Zhang , J Wei , H Zhang , E Zhang and F. Ma
 

The mechanism underlining human papillomaviruses (HPVs) causing cancer has been studied extensively, and it was concluded that the high-risk HPVs' E6 targeted and degraded tumor suppressor protein p53, leading to infected cells malignant transformation. In contrast, the low-risk HPVs only cause proliferative but non-invasive lesions of infected epithelia. Therefore, we hypothesized that low-risk HPVs' E6 might interact with p53 in a different pattern. We used a mammalian green fluorescent protein (GFP) expression system to express HPV-18E6 and HPV-6E6 fusion proteins in wild-type (wt) p53 cell lines, 293T and HEK293 cells, to investigate the traffic and location of E6s and p53. The results indicated GFP-18E6 was mainly expressed in nucleus, whereas GFP-6E6 was expressed exclusively in cytoplasm. Endogenous wt p53 was shown to be localized in the nuclei of cells transfected with GFP-18E6. Interestingly, for the first time, we observed that p53 was trapped in the cytoplasm and never translocated into the cell nuclei transfected with GFP-6E6. In conclusion, HPV-6E6 was responsible for the cytoplasmic localization of p53. Therefore, our experiments provide a new insight into the pathogenesis of HPV.

  X Fan , Y Liu , J Jiang , Z Ma , H Wu , T Liu , M Liu , X Li and H. Tang
 

MicroRNAs (miRNAs) are emerging as a class of small regulated RNAs, and the alterations of miRNAs are implicated in the initiation and progression of human cancers. Our study shows that inhibition of miR-20a in OVCAR3 ovarian cancer cell line could suppress, whereas overexpression of miR-20a could enhance cell long-term proliferation and invasion. We also confirmed amyloid precursor protein (APP) as a direct target gene of miR-20a. Furthermore, suppression of APP expression could also promote ovarian cancer cell proliferation and invasion, which is consistent with the results of miR-20a overexpression. Therefore, we concluded that the regulation of APP is an important mechanism for miR-20a to promote proliferation and invasion in ovarian cancer cells.

  J Du , Y Zhang , Y Liu , Y Li and X. Zhu
 

Cenp-F (also named mitosin) is a 350-kDa human kinetochore protein important for the mitotic progression. It is also a nuclear matrix protein in interphase cells. Here, we showed that overexpression of N-terminal deletion mutants of Cenp-F containing the C-terminal 112 residues induced chromatin condensation into numerous aggregates of varying sizes in interphase nucleus, colocalizing with the exogenous proteins. In situ hybridization using whole chromosome painting probes indicated that the chromatin aggregates were not prematurely condensed individual chromosomes. Neither were they due to apoptosis. We provided evidence showing association of Cenp-F with certain regions of interphase chromatin fibers. Cenp-F associated with the DNA-dependent protein kinase (DNA-PK), a trimeric protein complex critical for genome homeostasis. Moreover, the DNA-PK association activity of Cenp-F mutants correlated with their ability to induce chromatin aggregation. These results imply a role of Cenp-F in organization of interphase chromatin through association and possibly regulation of DNA-PK.

  Y Liu , S Chewchuk , C Lavigne , S Brule , G Pilon , V Houde , A Xu , A Marette and G. Sweeney
 

Endocrine effects of adipose-derived adiponectin on skeletal muscle have been shown to account, at least in part, for the anti-diabetic effects of this adipokine. Recently, the concept of myokines has gained credence, and the potential for skeletal muscle to produce adiponectin has been suggested. Here we demonstrated an increased level of adiponectin mRNA and protein expression as well as protein secretion in response to rosiglitazone treatment in L6 muscle cells. This correlated with the ability of rosiglitazone to enhance insulin sensitivity for stimulation of protein kinase B (Akt) phosphorylation and glucose transport; rosiglitazone also corrected high-glucose-induced insulin resistance in L6 cells. Overexpression of adiponectin confirmed the functional significance of local production of adiponectin in muscle cells via elevated glucose uptake and increased insulin sensitivity. In obese diabetic db/db mice, there was a change in the adiponectin expression profile in soleus and extensor digitorum longus (EDL) muscle with less high molecular weight (HMW) and more medium (MMW)/low (LMW) molecular weight species detected. Induction of obesity and insulin resistance in rats by feeding a high-fat high-sucrose diet also led to decreased muscle HMW adiponectin content that could be corrected by rosiglitazone treatment. In summary, we show the ability of skeletal muscle cells to produce adiponectin, which can mediate autocrine metabolic effects, thus establishing adiponectin as a bona fide myokine. We also demonstrate that skeletal muscle adiponectin production is altered in animal models of obesity and diabetes and that these changes can be corrected by rosiglitazone.

  D Choi , A Radziszewska , S. A Schroer , N Liadis , Y Liu , Y Zhang , P. P. L Lam , L Sheu , Z Hao , H. Y Gaisano and M. Woo
 

Fas/Fas ligand belongs to the tumor necrosis factor superfamily of receptors/ligands and is best known for its role in apoptosis. However, recent evidence supports its role in other cellular responses, including proliferation and survival. Although Fas has been implicated as an essential mediator of β-cell death in the pathogenesis of type 1 diabetes, the essential role of Fas specifically in pancreatic β-cells has been found to be controversial. Moreover, the role of Fas on β-cell homeostasis and function is not clear. The objective of this study is to determine the role of Fas specifically in β-cells under both physiological and diabetes models. Mice with Fas deletion specifically in the β-cells were generated using the Cre-loxP system. Cre-mediated Fas deletion was under the control of the rat insulin promoter. Absence of Fas in β-cells leads to complete protection against FasL-induced cell death. However, Fas is not essential in determining β-cell mass or susceptibility to streptozotocin- or HFD-induced diabetes. Importantly, Fas deletion in β-cells leads to increased p65 expression, enhanced glucose tolerance, and glucose-stimulated insulin secretion, with increased exocytosis as manifested by increased changes in membrane capacitance and increased expression of Syntaxin1A, VAMP2, and munc18a. Together, our study shows that Fas in the β-cells indeed plays an essential role in the canonical death receptor-mediated apoptosis but is not essential in regulating β-cell mass or diabetes development. However, β-cell Fas is critical in the regulation of glucose homeostasis through regulation of the exocytosis machinery.

  L. L Zhu , Y Liu , A. F Cui , D Shao , J. C Liang , X. J Liu , Y Chen , N Gupta , F. D Fang and Y. S. Chang
 

Peroxisome proliferator-activated receptor- coactivator-1 (PGC-1) is a key regulator of cellular energy metabolism and regulates processes such as adaptive thermogenesis, hepatic gluconeogenesis, fatty acid oxidation, and mitochondrial biogenesis by coactivating numerous nuclear receptors and transcription factors. Here, we demonstrate the presence of the ERR binding site in the regulatory sequence of the glucokinase gene and that PGC-1 coactivates ERR to stimulate the transcription of glucokinase. Simultaneous overexpression of PGC-1 and ERR potently induced the glucokinase gene expression and its enzymatic activity in primary hepatocytes; however, expression of either PGC-1 or ERR alone had no significant effect. Electrophoretic mobility shift and chromatin immunoprecipitation assays revealed the interaction of ERR with the glucokinase promoter. Finally, the knockdown of endogenous ERR with specific siRNA (siERR) or pharmacological inhibition of ERR with XCT790 attenuated insulin-induced glucokinase expression. Taken together, this research identifies glucokinase as a novel target of PGC-1/ERR and underscores the regulatory function of ERR in insulin-dependent enzyme regulation.

  E. G Cohen , S Baredes , L. S Zuckier , N. M Mirani , Y Liu and N. V. Ghesani
 

OBJECTIVE. It has been suggested that 18F-FDG uptake determined by PET can differentiate squamous cell carcinoma from benign sinonasal papilloma. We wish to present our experience with sinonasal papillomas and PET/CT to determine if the degree of FDG uptake is indicative of benign or malignant disease.

CONCLUSION. Benign sinonasal papilloma may be associated with intense FDG uptake on PET/CT. FDG PET/CT does not appear to reliably differentiate benign from malignant sinonasal papilloma.

  D. S. C Lam , S. K Rao , A. H Fan , N. G Congdon , V Wong , Y Liu and P. T. H. Lam
 

Objectives  To describe a modified manual cataract extraction technique, sutureless large-incision manual cataract extraction (SLIMCE), and to report its clinical outcomes.

Methods  Case notes of 50 consecutive patients with cataract surgery performed using the SLIMCE technique were retrospectively reviewed. Clinical outcomes 3 months after surgery were analyzed, including postoperative uncorrected visual acuity, best-corrected visual acuity, intraoperative and postoperative complications, endothelial cell loss, and surgically induced astigmatism using the vector analysis method.

Results  At the 3-month follow-up, all 50 patients had postoperative best-corrected visual acuity of at least 20/60, and 37 patients (74%) had visual acuity of at least 20/30. Uncorrected visual acuity was at least 20/68 in 28 patients (56%) and was between 20/80 and 20/200 in 22 patients (44%). No significant intraoperative complications were encountered, and sutureless wounds were achieved in all but 2 patients. At the 3-month follow-up, endothelial cell loss was 3.9%, and the mean surgically induced astigmatism was 0.69 diopter.

Conclusions  SLIMCE is a safe and effective manual cataract extraction technique with low rates of surgically induced astigmatism and endothelial cell loss. In view of its low cost, SLIMCE may have a potential role in reducing cataract blindness in developing countries.

  A Thind , A Diamant , Y Liu and R. Maly
 

Objective  To analyze the relationship between patient satisfaction with surgical treatment and 4 consultation skills and processes of the surgeons (time spent, listens carefully, explains concepts in a way the patient can understand, and shows respect for what the patient has to say), controlling for a range of patient, surgeon, and treatment characteristics.

Design  Cross-sectional survey.

Setting  The Breast and Cervical Cancer Treatment Program for the state of California.

Patients  A statewide sample of 789 low-income women who received treatment for breast cancer from February 1, 2003, through September 31, 2005.

Main Outcome Measure  Satisfaction with surgical treatment.

Results  Three of every 4 women reported being extremely satisfied with the treatment they received from their surgeon. African American women and those with arm swelling were less likely to be satisfied, whereas those reporting that the surgeon always spent enough time and explained concepts in a way they could understand were more likely to report greater satisfaction.

Conclusion  Our findings highlight the importance of 2 relatively simple behaviors that surgeons can easily implement to increase patient satisfaction, which can be of potential benefit in the litigious world of today.

  A. C Lozano , N Abe , Y Liu and S. Rosset
 

We consider the problem of discovering gene regulatory networks from time-series microarray data. Recently, graphical Granger modeling has gained considerable attention as a promising direction for addressing this problem. These methods apply graphical modeling methods on time-series data and invoke the notion of ‘Granger causality’ to make assertions on causality through inference on time-lagged effects. Existing algorithms, however, have neglected an important aspect of the problem—the group structure among the lagged temporal variables naturally imposed by the time series they belong to. Specifically, existing methods in computational biology share this shortcoming, as well as additional computational limitations, prohibiting their effective applications to the large datasets including a large number of genes and many data points. In the present article, we propose a novel methodology which we term ‘grouped graphical Granger modeling method’, which overcomes the limitations mentioned above by applying a regression method suited for high-dimensional and large data, and by leveraging the group structure among the lagged temporal variables according to the time series they belong to. We demonstrate the effectiveness of the proposed methodology on both simulated and actual gene expression data, specifically the human cancer cell (HeLa S3) cycle data. The simulation results show that the proposed methodology generally exhibits higher accuracy in recovering the underlying causal structure. Those on the gene expression data demonstrate that it leads to improved accuracy with respect to prediction of known links, and also uncovers additional causal relationships uncaptured by earlier works.

Contact: aclozano@us.ibm.com

  X Zheng , X. X Cui , Z Gao , Y Zhao , Y Lin , W. J Shih , M. T Huang , Y Liu , A Rabson , B Reddy , C. S Yang and A. H. Conney
 

Epidemiology studies suggest that statins and nonsteroidal anti-inflammatory drugs reduce the risk of prostate cancer. In the present study, LNCaP cells were cultured in regular medium containing fetal bovine serum or in medium supplemented with charcoal-stripped fetal bovine serum to mimic androgen deprivation treatment. We found that atorvastatin (Lipitor) or celecoxib (Celebrex) treatment of LNCaP cells cultured in regular or androgen-depleted medium inhibited growth and stimulated apoptosis. A combination of atorvastatin and celecoxib was more effective than either agent alone. In animal studies, severe combined immunodeficient mice were injected s.c. with LNCaP cells in Matrigel. After 4 to 6 weeks, mice with LNCaP tumors (about 0.6 cm wide and 0.6 cm long) were surgically castrated and received daily i.p. injections of vehicle, atorvastatin (10 µg/g body weight/d), celecoxib (10 µg/g/d), or a combination of atorvastatin (5 µg/g/d) and celecoxib (5 µg/g/d) for 42 days. In all groups, the androgen-dependent LNCaP tumors regressed initially in response to castration, but the tumors eventually progressed to androgen independence and started to grow. Treatment of the mice with atorvastatin or celecoxib alone suppressed the regrowth of LNCaP tumors after castration. A combination of low doses of atorvastatin and celecoxib had a more potent effect in inhibiting the growth and progression of LNCaP tumors to androgen independence than a higher dose of either agent alone. Our results indicate that administration of a combination of atorvastatin and celecoxib may be an effective strategy for the prevention of prostate cancer progression from androgen dependence to androgen independence. Cancer Prev Res; 3(1); 114–24

  R Strauss , P Sova , Y Liu , Z. Y Li , S Tuve , D Pritchard , P Brinkkoetter , T Moller , O Wildner , S Pesonen , A Hemminki , N Urban , C Drescher and A. Lieber
 

We studied the susceptibility of primary ovarian cancer cells to oncolytic adenoviruses. Using gene expression profiling of cancer cells either resistant or susceptible to viral oncolysis, we discovered that the epithelial phenotype of ovarian cancer represents a barrier to infection by commonly used oncolytic adenoviruses targeted to coxsackie-adenovirus receptor or CD46. Specifically, we found that these adenovirus receptors were trapped in tight junctions and not accessible for virus binding. Accessibility to viral receptors was critically linked to depolarization and the loss of tight and adherens junctions, both hallmarks of epithelial-to-mesenchymal transition (EMT). We showed that specific, thus far little-explored adenovirus serotypes (Ad3, Ad7, Ad11, and Ad14) that use receptor(s) other than coxsackie-adenovirus receptor and CD46 were able to trigger EMT in epithelial ovarian cancer cells and cause efficient oncolysis. Our studies on ovarian cancer cultures and xenografts also revealed several interesting cancer cell biology features. Tumors in situ as well as tumor xenografts in mice mostly contained epithelial cells and cells that were in a hybrid stage where they expressed both epithelial and mesenchymal markers (epithelial/mesenchymal cells). These epithelial/mesenchymal cells are the only xenograft-derived cells that can be cultured and with passaging undergo EMT and differentiate into mesenchymal cells. Our study provides a venue for improved virotherapy of cancer as well as new insights into cancer cell biology. [Cancer Res 2009;69(12):5115–25]

  Y Gao , Y He , J Ding , K Wu , B Hu , Y Liu , Y Wu , B Guo , Y Shen , D Landi , S Landi , Y Zhou and H. Liu
 

Hepatocellular carcinoma (HCC) is the fifth most common malignancy caused by environmental and genetic factors. MicroRNAs (miRNAs) are a class of short non-coding RNAs with posttranscriptional regulatory functions. They participate in diverse biological pathways and function as gene regulators. Genetic polymorphisms in 3' untranslated regions (3' UTRs) targeted by miRNAs alter the strength of miRNA binding, with consequences on regulation of target genes thereby affecting the individual's cancer risk. We have previously predicted polymorphisms falling in miRNA-binding regions of cancer genes. We selected an insertion/deletion (Indel) polymorphism (rs3783553) in the 3' UTR of interleukin (IL)-1 (IL1A) for a case–control study in a Chinese population. With samples from 403 HCC patients and 434 healthy control individuals, strong evidence of association was observed for the variant homozygote. This association was validated in a second independent case–control study with 1074 HCC patients and 1239 healthy control individuals (odds ratio = 0.62; 95% confidence interval = 0.49–0.78). We further show that the ‘TTCA’ insertion allele for rs3783553 disrupts a binding site for miR-122 and miR-378, thereby increasing transcription of IL-1 in vitro and in vivo. These findings suggest that functional polymorphism rs3783553 in IL1A could contribute to HCC susceptibility. Considering IL-1 affects not only various phases of the malignant process, such as carcinogenesis, tumor growth and invasiveness, but also patterns of interactions between malignant cells and the host's immune system, our results indicated that IL-1 may be a promising target for immunotherapy, early diagnosis and intervention of HCC.

  Y Liu , S Shete , L. E Wang , R El Zein , C. J Etzel , F. W Liang , G Armstrong , S Tsavachidis , M. R Gilbert , K. D Aldape , J Xing , X Wu , Q Wei and M. L. Bondy
 

Background: DNA strand breaks pose the greatest threat to genomic stability. Genetically determined mutagen sensitivity predisposes individuals to a variety of cancers, including glioma. However, polymorphisms in DNA strand break repair genes that may determine mutagen sensitivity are not well studied in cancer risk, especially in gliomas.

Methods: We correlated genotype data for tag single-nucleotide polymorphisms (tSNPs) of DNA strand break repair genes with a gamma-radiation-induced mutagen sensitivity phenotype [expressed as mean breaks per cell (B/C)] in samples from 426 glioma patients. We also conducted analysis to assess joint and haplotype effects of single-nucleotide polymorphisms (SNPs) on mutagen sensitivity. We further validate our results in an independent external control group totaling 662 subjects.

Results: Of the 392 tSNPs examined, we found that mutagen sensitivity was modified by one tSNP in the EME2 gene and six tSNPs in the RAD51L1 gene (P < 0.01). Among the six RAD51L1 SNPs tested in the validation set, one (RAD51L1 rs2180611) was significantly associated with mutagen sensitivity (P = 0.025). Moreover, we found a significant dose–response relationship between the mutagen sensitivity and the number of adverse tSNP genotypes. Furthermore, haplotype analysis revealed that RAD51L1 haplotypes F-A (zero adverse allele) and F-E (six adverse alleles) exhibited the lowest (0.42) and highest (0.93) mean B/C values, respectively. A similar dose–response relationship also existed between the mutagen sensitivity and the number of adverse haplotypes.

Conclusion: These results suggest that polymorphisms in and haplotypes of the RAD51L1 gene, which is involved in the double-strand break repair pathway, modulate gamma-radiation-induced mutagen sensitivity.

  J. A Schwartzbaum , Y Xiao , Y Liu , S Tsavachidis , M. S Berger , M. L Bondy , J. S Chang , S. M Chang , P. A Decker , B Ding , S. J Hepworth , R. S Houlston , F. J Hosking , R. B Jenkins , M. L Kosel , L. S McCoy , P. A McKinney , K Muir , J. S Patoka , M Prados , T Rice , L. B Robertson , M. J Schoemaker , S Shete , A. J Swerdlow , J. L Wiemels , J. K Wiencke , P Yang and M. R. Wrensch
 

To determine whether inherited variations in immune function single-nucleotide polymorphisms (SNPs), genes or pathways affect glioblastoma risk, we analyzed data from recent genome-wide association studies in conjunction with predefined immune function genes and pathways. Gene and pathway analyses were conducted on two independent data sets using 6629 SNPs in 911 genes on 17 immune pathways from 525 glioblastoma cases and 602 controls from the University of California, San Francisco (UCSF) and a subset of 6029 SNPs in 893 genes from 531 cases and 1782 controls from MD Anderson (MDA). To further assess consistency of SNP-level associations, we also compared data from the UK (266 cases and 2482 controls) and the Mayo Clinic (114 cases and 111 controls). Although three correlated epidermal growth factor receptor (EGFR) SNPs were consistently associated with glioblastoma in all four data sets (Mantel–Haenzel P values = 1 x 10–5 to 4 x 10–3), independent replication is required as genome-wide significance was not attained. In gene-level analyses, eight immune function genes were significantly (minP < 0.05) associated with glioblastoma; the IL-2RA (CD25) cytokine gene had the smallest minP values in both UCSF (minP = 0.01) and MDA (minP = 0.001) data sets. The IL-2RA receptor is found on the surface of regulatory T cells potentially contributing to immunosuppression characteristic of the glioblastoma microenvironment. In pathway correlation analyses, cytokine signaling and adhesion–extravasation–migration pathways showed similar associations with glioblastoma risk in both MDA and UCSF data sets. Our findings represent the first systematic description of immune genes and pathways that characterize glioblastoma risk.

  Z Dong , Y Liu , K. F Scott , L Levin , K Gaitonde , R. B Bracken , B Burke , Q. J Zhai , J Wang , L Oleksowicz and S. Lu
 

The majority of prostate cancers are indolent, whereas a significant portion of patients will require systemic treatment during the course of their disease. To date, only high Gleason scores are best associated with a poor prognosis in prostate cancer. No validated serum biomarker has been identified with prognostic power. Previous studies showed that secretory phospholipase A2-IIa (sPLA2-IIa) is overexpressed in almost all human prostate cancer specimens and its elevated levels are correlated with high tumor grade. Here, we found that sPLA2-IIa is overexpressed in androgen-independent prostate cancer LNCaP-AI cells relative to their androgen-dependent LNCaP cell counterparts. LNCaP-AI cells also secrete significantly higher levels of sPLA2-IIa. Blocking sPLA2-IIa function compromises androgen-independent cell growth. Inhibition of the ligand-induced signaling output of the HER network, by blocking PI3K-Akt signaling and the nuclear factor-kappaB (NF-B)-mediated pathway, compromises both sPLA2-IIa protein expression and secretion, as a result of downregulation of sPLA2-IIa promoter activity. More importantly, we demonstrated elevated serum sPLA2-IIa levels in prostate cancer patients. High serum sPLA2-IIa levels are associated significantly with high Gleason score and advanced disease stage. Increased sPLA2-IIa expression was confirmed in prostate cancer cells, but not in normal epithelium and stroma by immunohistochemistry analysis. We showed that elevated signaling of the HER/HER2-PI3K-Akt-NF-B pathway contributes to sPLA2-IIa overexpression and secretion by prostate cancer cells. Given that sPLA2-IIa overexpression is associated with prostate development and progression, serum sPLA2-IIa may serve as a prognostic biomarker for prostate cancer and a potential surrogate prostate biomarker indicative of tumor burden.

  M McGeachie , R. L. B Ramoni , J. C Mychaleckyj , K. L Furie , J. M Dreyfuss , Y Liu , D Herrington , X Guo , J. A Lima , W Post , J. I Rotter , S Rich , M Sale and M. F. Ramoni
 

Background— Many different genetic and clinical factors have been identified as causes or contributors to atherosclerosis. We present a model of preclinical atherosclerosis based on genetic and clinical data that predicts the presence of coronary artery calcification in healthy Americans of European descent 45 to 84 years of age in the Multi-Ethnic Study of Atherosclerosis (MESA).

Methods and Results— We assessed 712 individuals for the presence or absence of coronary artery calcification and assessed their genotypes for 2882 single-nucleotide polymorphisms. With the use of these single-nucleotide polymorphisms and relevant clinical data, a Bayesian network that predicts the presence of coronary calcification was constructed. The model contained 13 single-nucleotide polymorphisms (from genes AGTR1, ALOX15, INSR, PRKAB1, IL1R2, ESR2, KCNK1, FBLN5, PPARA, VEGFA, PON1, TDRD6, PLA2G7, and 1 ancestry informative marker) and 5 clinical variables (sex, age, weight, smoking, and diabetes mellitus) and achieved 85% predictive accuracy, as measured by area under the receiver operating characteristic curve. This is a significant (P<0.001) improvement on models that use just the single-nucleotide polymorphism data or just the clinical variables.

Conclusions— We present an investigation of joint genetic and clinical factors associated with atherosclerosis that shows predictive results for both cases, as well as enhanced performance for their combination.

  J Shen , U. M Chandrasekharan , M. Z Ashraf , E Long , R. E Morton , Y Liu , J. D Smith and P. E. DiCorleto
 

Rationale: Multiple protein kinases have been implicated in cardiovascular disease; however, little is known about the role of their counterparts: the protein phosphatases.

Objective: To test the hypothesis that mitogen-activated protein kinase phosphatase (MKP)-1 is actively involved in atherogenesis.

Methods and Results: Mice with homozygous deficiency in MKP-1 (MKP-1–/–) were bred with apolipoprotein (Apo)E-deficient mice (ApoE–/–) and the 3 MKP-1 genotypes (MKP-1+/+/ApoE–/– ; MKP-1+/–/ApoE–/– and MKP-1–/–/ApoE–/–) were maintained on a normal chow diet for 16 weeks. The 3 groups of mice exhibited similar body weight and serum lipid profiles; however, both MKP-1+/– and MKP-1–/– mice had significantly less aortic root atherosclerotic lesion formation than MKP-1+/+ mice. Less en face lesion was observed in 8-month-old MKP-1–/– mice. The reduction in atherosclerosis was accompanied by decreased plasma levels of interleukin-1 and tumor necrosis factor , and preceded by increased antiinflammatory cytokine interleukin-10. In addition, MKP-1–null mice had higher levels of plasma stromal cell–derived factor-1a, which negatively correlated with atherosclerotic lesion size. Immuno-histochemical analysis revealed that MKP-1 expression was enriched in macrophage-rich areas versus smooth muscle cell regions of the atheroma. Furthermore, macrophages isolated from MKP-1–null mice showed dramatic defects in their spreading/migration and impairment in extracellular signal-regulated kinase, but not c-Jun N-terminal kinase and p38, pathway activation. In line with this, MKP-1–null atheroma exhibited less macrophage content. Finally, transplantation of MKP-1–intact bone marrow into MKP-1–null mice fully rescued the wild-type atherosclerotic phenotype.

Conclusion: These findings demonstrate that chronic deficiency of MKP-1 leads to decreased atherosclerosis via mechanisms involving impaired macrophage migration and defective extracellular signal-regulated kinase signaling.

  S Mangos , P. y Lam , A Zhao , Y Liu , S Mudumana , A Vasilyev , A Liu and I. A. Drummond
  Steve Mangos, Pui-ying Lam, Angela Zhao, Yan Liu, Sudha Mudumana, Aleksandr Vasilyev, Aiping Liu, and Iain A. Drummond

Mutations in polycystin1 (PKD1) account for the majority of autosomal dominant polycystic kidney disease (ADPKD). PKD1 mutations are also associated with vascular aneurysm and abdominal wall hernia, suggesting a role for polycystin1 in extracellular matrix (ECM) integrity. In zebrafish, combined knockdown of the PKD1 paralogs pkd1a and pkd1b resulted in dorsal axis curvature, hydrocephalus, cartilage and craniofacial defects, and pronephric cyst formation at low frequency (10–15%). Dorsal axis curvature was identical to the axis defects observed in pkd2 knockdown embryos. Combined pkd1a/b, pkd2 knockdown demonstrated that these genes interact in axial morphogenesis. Dorsal axis curvature was linked to notochord collagen overexpression and could be reversed by knockdown of col2a1 mRNA or chemical inhibition of collagen crosslinking. pkd1a/b- and pkd2-deficient embryos exhibited ectopic, persistent expression of multiple collagen mRNAs, suggesting a loss of negative feedback signaling that normally limits collagen gene expression. Knockdown of pkd1a/b also dramatically sensitized embryos to low doses of collagen-crosslinking inhibitors, implicating polycystins directly in the modulation of collagen expression or assembly. Embryos treated with wortmannin or LY-29400 also exhibited dysregulation of col2a1 expression, implicating phosphoinositide 3-kinase (PI3K) in the negative feedback signaling pathway controlling matrix gene expression. Our results suggest that pkd1a/b and pkd2 interact to regulate ECM secretion or assembly, and that altered matrix integrity may be a primary defect underlying ADPKD tissue pathologies.

  W Zhang , L Wang , Y Liu , J Xu , G Zhu , H Cang , X Li , M Bartlam , K Hensley , G Li , Z Rao and X. C. Zhang
 

Eukaryotic lanthionine synthetase C-like protein 1 (LanCL1) is homologous to prokaryotic lanthionine cyclases, yet its biochemical functions remain elusive. We report the crystal structures of human LanCL1, both free of and complexed with glutathione, revealing glutathione binding to a zinc ion at the putative active site formed by conserved GxxG motifs. We also demonstrate by in vitro affinity analysis that LanCL1 binds specifically to the SH3 domain of a signaling protein, Eps8. Importantly, expression of LanCL1 mutants defective in Eps8 interaction inhibits nerve growth factor (NGF)-induced neurite outgrowth, providing evidence for the biological significance of this novel interaction in cellular signaling and differentiation.

  H. H Liu , P Lu , Y Guo , E Farrell , X Zhang , M Zheng , B Bosano , Z Zhang , J Allard , G Liao , S Fu , J Chen , K Dolim , A Kuroda , J Usuka , J Cheng , W Tao , K Welch , Y Liu , J Pease , S. A de Keczer , M Masjedizadeh , J. S Hu , P Weller , T Garrow and G. Peltz
 

Acetaminophen-induced liver toxicity is the most frequent precipitating cause of acute liver failure and liver transplant, but contemporary medical practice has mainly focused on patient management after a liver injury has been induced. An integrative genetic, transcriptional, and two-dimensional NMR-based metabolomic analysis performed using multiple inbred mouse strains, along with knowledge-based filtering of these data, identified betaine-homocysteine methyltransferase 2 (Bhmt2) as a diet-dependent genetic factor that affected susceptibility to acetaminophen-induced liver toxicity in mice. Through an effect on methionine and glutathione biosynthesis, Bhmt2 could utilize its substrate (S-methylmethionine [SMM]) to confer protection against acetaminophen-induced injury in vivo. Since SMM is only synthesized in plants, Bhmt2 exerts its beneficial effect in a diet-dependent manner. Identification of Bhmt2 and the affected biosynthetic pathway demonstrates how a novel method of integrative genomic analysis in mice can provide a unique and clinically applicable approach to a major public health problem.

  Y Liu , Y Wang , C Wu and P. Zheng
 

The majority of the Lafora's disease (LD) is caused by defect in the EPM2A gene, including missense and nonsense mutations and deletions. These defects mainly occur in the carbohydrate-binding domain, and how these mutations cause neuronal defects is under active investigation. Here, we report that the mutant proteins encoded by all missense mutations and most deletions tested are unstable, insoluble and ubiquitinated, and are accumulated in aggresome-like structures. The effect of apparent ‘gain-of-function’ mutations can be corrected by co-transfection of wild-type EPM2A cDNA, which is consistent with the recessive nature of these mutations in LD patients. In a neuronal cell line, these mutant aggregates exacerbate endoplasm reticulum (ER) stress and make the cells susceptible to the apoptosis induced by ER stressor, thapsigargin. The chemical chaperon, 4-phenylbutyrate, increased the mutant solubility, reduced the ER stress and dulled the sensitivity of mutant neuronal cells to apoptosis induced by thapsigargin and the mutant laforin proteins. The increased sensitivity to ER stress-induced apoptosis may contribute to LD pathogenesis.

  D. M Zuo , L. Y Zhang , X Lu , Y Liu and Z. L. Chen
 

Mannan-binding lectin (MBL) is a C-type serum lectin, which is believed to play an important role in the innate immunity against a variety of pathogens. MBL can bind to sugar determinants of a wide variety of microorganisms, neutralize them and inhibit infection by complement activation through the lectin pathway and opsonization by collectin receptors. Given that small intestine is a predominant site of extrahepatic expression of MBL, here we addressed the question whether MBL is involved in mucosal innate immunity. The carbohydrate recognition domain (CRD) genes of mouse MBL-C (mMBL-C) were cloned and expressed in Escherichia coli. Recombinant mMBL-C-CRD binds to Shigella flexneri 2a in a calcium-dependent manner and that interaction could be blocked by the anti-mMBL-C-CRD antibody. mMBL-C-CRD protein could inhibit the adhesion of S. flexneri 2a to intestinal mucosa, while administration of anti-mMBL-C-CRD antibody caused an increased level of bacteria adhesion in vitro. Administration of recombinant mMBL-C-CRD protein reduced the secretion of IL-6 and monocyte chemoattractant protein 1 from primary intestinal epithelial cells stimulated with S. flexneri 2a. Furthermore, neutralization of MBL activity by anti-MBL-C-CRD resulted in a significant increase in the number of S. flexneri 2a that colonized the intestines of BALB/c mice and attenuated the severity of inflammation seen in the areas of bacterial invasion. These findings suggest that mMBL-C may protect host intestinal mucosa by directly binding to the bacteria.

  G Di Leva , P Gasparini , C Piovan , A Ngankeu , M Garofalo , C Taccioli , M. V Iorio , M Li , S Volinia , H Alder , T Nakamura , G Nuovo , Y Liu , K. P Nephew and C. M. Croce
  Background

Several lines of evidence have suggested that estrogen receptor (ER)–negative breast tumors, which are highly aggressive and nonresponsive to hormonal therapy, arise from ER-positive precursors through different molecular pathways. Because microRNAs (miRNAs) modulate gene expression, we hypothesized that they may have a role in ER-negative tumor formation.

Methods

Gene expression profiles were used to highlight the global changes induced by miRNA modulation of ER protein. miRNA transfection and luciferase assays enabled us to identify new targets of miRNA 206 (miR-206) and miRNA cluster 221-222 (miR-221-222). Northern blot, luciferase assays, estradiol treatment, and chromatin immunoprecipitation were performed to identify the miR-221-222 transcription unit and the mechanism implicated in its regulation.

Results

Different global changes in gene expression were induced by overexpression of miR-221-222 and miR-206 in ER-positive cells. miR-221 and -222 increased proliferation of ER-positive cells, whereas miR-206 had an inhibitory effect (mean absorbance units [AU]: miR-206: 500 AU, 95% confidence interval [CI]) = 480 to 520; miR-221: 850 AU, 95% CI = 810 to 873; miR-222: 879 AU, 95% CI = 850 to 893; P < .05). We identified hepatocyte growth factor receptor and forkhead box O3 as new targets of miR-206 and miR-221-222, respectively. We demonstrated that ER negatively modulates miR-221 and -222 through the recruitment of transcriptional corepressor partners: nuclear receptor corepressor and silencing mediator of retinoic acid and thyroid hormone receptor.

Conclusions

These findings suggest that the negative regulatory loop involving miR-221-222 and ER may confer proliferative advantage and migratory activity to breast cancer cells and promote the transition from ER-positive to ER-negative tumors.

  R. M Osipov , M. P Robich , J Feng , R. T Clements , Y Liu , H. P Glazer , J Wagstaff , C Bianchi and F. W. Sellke
 

Myocardial ischemia-reperfusion (IR) injury occurs frequently in the setting of hypercholesterolemia. We investigated the potential efficacy of a novel thrombin fragment (TP508) on IR injury in a hypercholesterolemic porcine model. Twenty-one hypercholesterolemic male Yucatan pigs underwent 60 min of mid-left anterior descending coronary artery occlusion followed by 120 min of reperfusion. Pigs received either placebo (control, n = 7) or TP508 in two doses (TP508 low dose, n = 7, as bolus of 0.5 mg/kg 50 min into ischemia and an infusion of 1.25 mg·kg–1·h–1 during reperfusion period or TP508 high dose, n = 7, a double dose of TP508 low-dose group). Myocardial function was monitored throughout the experiment. The area at risk and myocardial necrosis were determined by Monastryl blue/triphenyl tetrazolium chloride staining. Apoptosis in the ischemic territory was assessed. Coronary microvascular reactivity to endothelium-dependent and -independent factors was measured. Myocardial necrosis was lower in both TP508-treated groups vs. control (P < 0.05). Regional left ventricular function was improved only in the TP508 high-dose group (P < 0.05). Endothelium-dependent coronary microvascular reactivity was greater in both TP508-treated groups (P < 0.05) vs. control. The expression of proteins favoring cell survival, 90-kDa heat shock protein and phospho-Bad (Ser112) was higher in the TP508 high-dose group (P < 0.05). The expression of the cell death signaling proteins, cleaved caspase-3 (P < 0.05), apoptosis-inducing factor (P < 0.05), and poly-ADP ribose polymerase (P = 0.07) was lower in the TP508 low-dose group vs. TP508 high-dose and control. The terminal deoxynucleotidyl transferase dUTP-mediated nick-end labeling positive cell count was lower in both TP508 groups compared with the control (P < 0.05). This study demonstrates that, in hypercholesterolemic pigs, TP508 decreases myocardial necrosis and apoptosis after IR. Thus TP508 may offer a novel approach in protecting the myocardium from IR injury.

  Y Wu , H Li , R. J. F Loos , Q Qi , F. B Hu , Y Liu and X. Lin
 

We previously found that plasma RBP4 levels were strongly associated with metabolic syndrome components. This study aimed to determine whether RBP4 variants are associated with the metabolic syndrome components and plasma RBP4 levels, and to investigate whether the associations between plasma RBP4 and the metabolic syndrome components are causal. Five tagSNPs were tested for their associations with plasma RBP4 levels and metabolic syndrome components in a population-based sample of 3,210 Chinese Hans. A possible causal relationship between plasma RBP4 levels and hypertriglyceridemia was explored by Mendelian randomization. Plasma RBP4 levels were significantly associated with rs10882273 (βz –0.10SD[–0.17, –0.03], P = 0.0050), rs3758538 (βz –0.13SD[–0.24, –0.02], P = 0.0249) in all participants, and with rs17108993 in Shanghai participants (βz –0.19SD[–0.32, –0.05], P = 0.0061). The single nucleotide polymorphism (SNP) rs3758538 was significantly associated with hypertriglyceridemia (OR 0.62[0.45–0.85], P = 0.0026) and triglycerides (βz –0.19SD[–0.30, –0.07], P = 0.001) in all participants. In Mendelian randomization analysis, the observed effect size of association between rs3758538 and hypertriglyceridemia was different from the expected effect size (P = 0.0213). This is the first study to show that the RBP4 variants are significantly associated with plasma RBP4 levels and hypertriglyceridemia risk in Chinese Hans. However, results of Mendelian randomization do not support the hypothesis that RBP4 levels are causally related to hypertriglyceridemia risk.

  F. Y Lee , T. Q de Aguiar Vallim , H. K Chong , Y Zhang , Y Liu , S. A Jones , T. F Osborne and P. A. Edwards
 

The nuclear receptor, farnesoid X receptor (FXR, NR1H4), is known to regulate cholesterol, bile acid, lipoprotein, and glucose metabolism. In the current study, we provide evidence to support a role for FXR in hepatoprotection from acetaminophen (APAP)-induced toxicity. Pharmacological activation of FXR induces the expression of several genes involved in phase II and phase III xenobiotic metabolism in wild-type, but not Fxr–/– mice. We used chromatin immunoprecipitation-based genome-wide response element analyses coupled with luciferase reporter assays to identify functional FXR response elements within promoters, introns, or intragenic regions of these genes. Consistent with the observed transcriptional changes, FXR gene dosage is positively correlated with the degree of protection from APAP-induced hepatotoxicity in vivo. Further, we demonstrate that pretreatment of wild-type mice with an FXR-specific agonist provides significant protection from APAP-induced hepatotoxicity. Based on these findings, we propose that FXR plays a role in hepatic xenobiotic metabolism and, when activated, provides hepatoprotection against toxins such as APAP.

  G. S Song , H. L Zhai , Y. G Peng , L Zhang , G Wei , X. Y Chen , Y. G Xiao , L Wang , Y. J Chen , B Wu , B Chen , Y Zhang , H Chen , X. J Feng , W. K Gong , Y Liu , Z. J Yin , F Wang , G. Z Liu , H. L Xu , X. L Wei , X. L Zhao , P. B. F Ouwerkerk , T Hankemeier , T Reijmers , R. v. d Heijden , C. M Lu , M Wang , J. v. d Greef and Z. Zhu
 

Heterosis is a biological phenomenon whereby the offspring from two parents show improved and superior performance than either inbred parental lines. Hybrid rice is one of the most successful apotheoses in crops utilizing heterosis. Transcriptional profiling of F1 super-hybrid rice Liangyou-2186 and its parents by serial analysis of gene expression (SAGE) revealed 1183 differentially expressed genes (DGs), among which DGs were found significantly enriched in pathways such as photosynthesis and carbon-fixation, and most of the key genes involved in the carbon-fixation pathway exhibited up-regulated expression in F1 hybrid rice. Moreover, increased catabolic activity of corresponding enzymes and photosynthetic efficiency were also detected, which combined to indicate that carbon fixation is enhanced in F1 hybrid, and might probably be associated with the yield vigor and heterosis in super-hybrid rice. By correlating DGs with yield-related quantitative trait loci (QTL), a potential relationship between differential gene expression and phenotypic changes was also found. In addition, a regulatory network involving circadian-rhythms and light signaling pathways was also found, as previously reported in Arabidopsis, which suggest that such a network might also be related with heterosis in hybrid rice. Altogether, the present study provides another view for understanding the molecular mechanism underlying heterosis in rice.

  H Wang , Y Liu , M Briesemann and J. Yan
 

Sleep is an animal behavior shared by a wide range of species, suggesting that it must serve fundamental functions. However, the functions and molecular mechanisms underlying sleep are largely unknown. Through a meta-analysis of all available short-term sleep deprivation (SD) microarray data in mouse brain, we identified 91 key mouse SD-affected genes and two RBM3 isoforms showing opposite changes of expression during SD. Although most of the key SD-affected genes showed consistent changes of expression during SD across brain subregions despite their heterogeneous basal expression levels, we also identified the genes whose SD responses strongly depend upon the brain subregion. A gene regulatory network was also constructed for these genes showing that cAMP-responsive element (CRE) is one of the key cis-regulatory elements controlling SD-affected genes. We observed that SD during an animal's normal sleeping time could significantly disturb the circadian oscillation of clock genes. Surprisingly, synaptogenesis markers were significantly underexpressed in SD mice, differing from the previous findings in rat and fly. Comparing SD microarray data in mouse, rat, sparrow, and fly, we identified Egr and Nr4a gene families as conserved SD-affected genes, thus shedding new light on the origin of sleep in animals.

  F Cao , X Li , S Hiew , H Brady , Y Liu and Y. Dou
 

Small RNAs play important roles in the establishment and maintenance of heterochromatin structures. We show the presence of telomere specific small RNAs (tel-sRNAs) in mouse embryonic stem cells that are ~24 nucleotides in length, Dicer-independent, and 2'-O-methylated at the 3' terminus. The tel-sRNAs are asymmetric with specificity toward telomere G-rich strand, and evolutionarily conserved from protozoan to mammalian cells. Furthermore, tel-sRNAs are up-regulated in cells that carry null mutation of H3K4 methyltransferase MLL (Mll(–/–)) and down-regulated in cells that carry null mutations of histone H3K9 methyltransferase SUV39H (Suv39h1/h2(–/–)), suggesting that they are subject to epigenetic regulation. These results support that tel-sRNAs are heterochromatin associated pi-like small RNAs.

  M. S Lustgarten , Y. C Jang , Y Liu , F. L Muller , W Qi , M Steinhelper , S. V Brooks , L Larkin , T Shimizu , T Shirasawa , L. M McManus , A Bhattacharya , A Richardson and H. Van Remmen
 

In vitro studies of isolated skeletal muscle have shown that oxidative stress is limiting with respect to contractile function. Mitochondria are a potential source of muscle function-limiting oxidants. To test the hypothesis that skeletal muscle-specific mitochondrial oxidative stress is sufficient to limit muscle function, we bred mice expressing Cre recombinase driven by the promoter for the inhibitory subunit of troponin (TnIFast-iCre) with mice containing a floxed Sod2 (Sod2fl/fl) allele. Mn-SOD activity was reduced by 82% in glycolytic (mainly type II) muscle fiber homogenates from young TnIFastCreSod2fl/fl mice. Furthermore, Mn-SOD content was reduced by 70% only in type IIB muscle fibers. Aconitase activity was decreased by 56%, which suggests an increase in mitochondrial matrix superoxide. Mitochondrial superoxide release was elevated more than twofold by mitochondria isolated from glycolytic skeletal muscle in TnIFastCreSod2fl/fl mice. In contrast, the rate of mitochondrial H2O2 production was reduced by 33%, and only during respiration with complex II substrate. F2-isoprostanes were increased by 36% in tibialis anterior muscles isolated from TnIFastCreSod2fl/fl mice. Elevated glycolytic muscle-specific mitochondrial oxidative stress and damage in TnIFastCreSod2fl/fl mice were associated with a decreased ability of the extensor digitorum longus and gastrocnemius muscles to produce contractile force as a function of time, whereas force production by the soleus muscle was unaffected. TnIFastCreSod2fl/fl mice ran 55% less distance on a treadmill than wild-type mice. Collectively, these data suggest that elevated mitochondrial oxidative stress and damage in glycolytic muscle fibers are sufficient to reduce contractile muscle function and aerobic exercise capacity.

  Y Liu , D Zhou , N. A Abumrad and X. Su
 

ADP-ribosylation factor 6 (Arf6) is a small GTPase that influences membrane receptor trafficking and the actin cytoskeleton. In adipocytes, Arf6 regulates the trafficking of the glucose transporter type 4 (GLUT4) and consequently insulin-stimulated glucose transport. Previous studies also indicated a role of Arf6 in adrenergic receptor trafficking, but whether this contributes to the control of lipolysis in adipocytes remains unknown. This was examined in the present study by using RNA interference (RNAi) and pharmaceutical inhibition in murine cultured 3T3-L1 adipocytes. Downregulation of Arf6 by RNAi impairs isoproterenol-stimulated lipolysis specifically but does not alter triacylglycerol (TAG) synthesis or the insulin signaling pathway. Neither total TAG amounts nor TAG fatty acid compositions are altered. The inhibitory effect on lipolysis is mimicked by dynasore, a specific inhibitor for dynamin, which is required for endocytosis. In contrast, lipolysis triggered by reagents that bypass events at the plasma membrane (e.g., forskolin, isobutylmethylxanthine or 8-bromo-cAMP) is not affected. Moreover, Arf6 protein levels in white adipose tissues are markedly increased in ob/ob mice, whereas they are decreased in obesity-resistant CD36 null mice. These changes reflect at least in part alterations in Arf6 mRNA levels. Collectively, these results suggest a role of the endocytic pathway and its regulation by Arf6 in adrenergic stimulation of lipolysis in adipocytes and potentially in the development of obesity.

  F Sato , C Nagata , Y Liu , T Suzuki , J Kondo , S Morohashi , T Imaizumi , Y Kato and H. Kijima
 

PERIOD1 (PER1) is a clock gene. We examined the effect of knockdown of PER1 on apoptosis in pancreatic cancer (MIA PaCa-2 and PANC-1) and hepatocellular carcinoma (HepG2) cells. Transfection of siRNA against PER1 into these cells increased the cleaved forms of caspases and poly-ADP-ribose-polymerase and induced apoptosis in all three cell lines. In the two pancreatic cancer cell lines, PER1 knockdown resulted in upregulation of Bax and downregulation of Bcl-2. Expression of p53 was not altered in the two pancreatic cancer cell lines containing mutated p53, but was upregulated in the HepG2 cells containing wild-type p53. Cell proliferation of MIA PaCa-2 and HepG2 was inhibited by PER1 knockdown. We also examined, by immunohistochemical staining, the expression of PER1 in pancreatic cancer tissue and found that PER1 was strongly expressed in pancreatic cancer cells. These results indicate that PER1 acts as an anti-apoptotic factor in pancreatic cancer cells.

  Y Yang , J Weiner , Y Liu , A. J Smith , D. J Huss , R Winger , H Peng , P. D Cravens , M. K Racke and A. E. Lovett Racke
 

The extent to which myelin-specific Th1 and Th17 cells contribute to the pathogenesis of experimental autoimmune encephalomyelitis (EAE) is controversial. Combinations of interleukin (IL)-1β, IL-6, and IL-23 with transforming growth factor β were used to differentiate myelin-specific T cell receptor transgenic T cells into Th17 cells, none of which could induce EAE, whereas Th1 cells consistently transferred disease. However, IL-6 was found to promote the differentiation of encephalitogenic Th17 cells. Further analysis of myelin-specific T cells that were encephalitogenic in spontaneous EAE and actively induced EAE demonstrated that T-bet expression was critical for pathogenicity, regardless of cytokine expression by the encephalitogenic T cells. These data suggest that encephalitogenicity of myelin-specific T cells appears to be mediated by a pathway dependent on T-bet and not necessarily pathway-specific end products, such as interferon and IL-17.

  X Huang , X Bai , Y Cao , J Wu , M Huang , D Tang , S Tao , T Zhu , Y Liu , Y Yang , X Zhou , Y Zhao , M Wu , J Wei , D Wang , G Xu , S Wang , D Ma and J. Zhou
 

Angiogenesis is increasingly recognized as an important prognosticator associated with the progression of lymphoma and as an attractive target for novel modalities. We report a previously unrecognized mechanism by which lymphoma endothelium facilitates the growth and dissemination of lymphoma by interacting with circulated T cells and suppresses the activation of CD4+ T cells. Global gene expression profiles of microdissected endothelium from lymphoma and reactive lymph nodes revealed that T cell immunoglobulin and mucin domain–containing molecule 3 (Tim-3) was preferentially expressed in lymphoma-derived endothelial cells (ECs). Clinically, the level of Tim-3 in B cell lymphoma endothelium was closely correlated to both dissemination and poor prognosis. In vitro, Tim-3+ ECs modulated T cell response to lymphoma surrogate antigens by suppressing activation of CD4+ T lymphocytes through the activation of the interleukin-6–STAT3 pathway, inhibiting Th1 polarization, and providing protective immunity. In a lymphoma mouse model, Tim-3–expressing ECs promoted the onset, growth, and dissemination of lymphoma by inhibiting activation of CD4+ T cells and Th1 polarization. Our findings strongly argue that the lymphoma endothelium is not only a vessel system but also a functional barrier facilitating the establishment of lymphoma immune tolerance. These findings highlight a novel molecular mechanism that is a potential target for enhancing the efficacy of tumor immunotherapy and controlling metastatic diseases.

  S Zhu , W Pan , P Shi , H Gao , F Zhao , X Song , Y Liu , L Zhao , X Li , Y Shi and Y. Qian
 

Interleukin 17 (IL-17) plays critical roles in the pathogenesis of various autoimmune diseases, including experimental autoimmune encephalomyelitis (EAE). How the signals triggered by this powerful inflammatory cytokine are controlled to avoid abnormal inflammatory responses is not well understood. In this study, we report that TRAF3 is a receptor proximal negative regulator of IL-17 receptor (IL-17R) signaling. TRAF3 greatly suppressed IL-17–induced NF-B and mitogen-activated protein kinase activation and subsequent production of inflammatory cytokines and chemokines. Mechanistically, the binding of TRAF3 to IL-17R interfered with the formation of the receptor signaling activation complex IL-17R–Act1–TRAF6, resulting in suppression of downstream signaling. TRAF3 markedly inhibited IL-17–induced expression of inflammatory cytokine and chemokine genes in vivo and consequently delayed the onset and greatly reduced the incidence and severity of EAE. Thus, TRAF3 is a negative regulator of IL-17R proximal signaling.

  Y Liu , M Porta , J Qin , J Ramos , A Nani , T. R Shannon and M. Fill
 

The cardiac type 2 ryanodine receptor (RYR2) is activated by Ca2+-induced Ca2+ release (CICR). The inherent positive feedback of CICR is well controlled in cells, but the nature of this control is debated. Here, we explore how the Ca2+ flux (lumen-to-cytosol) carried by an open RYR2 channel influences its own cytosolic Ca2+ regulatory sites as well as those on a neighboring channel. Both flux-dependent activation and inhibition of single channels were detected when there were super-physiological Ca2+ fluxes (>3 pA). Single-channel results indicate a pore inhibition site distance of 1.2 ± 0.16 nm and that the activation site on an open channel is shielded/protected from its own flux. Our results indicate that the Ca2+ flux mediated by an open RYR2 channel in cells (~0.5 pA) is too small to substantially regulate (activate or inhibit) the channel carrying it, even though it is sufficient to activate a neighboring RYR2 channel.

 
 
 
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