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1.  A De Novo Genome Assembly Algorithm for Repeats and Nonrepeats 
BioMed Research International  2014;2014:736473.
Background. Next generation sequencing platforms can generate shorter reads, deeper coverage, and higher throughput than those of the Sanger sequencing. These short reads may be assembled de novo before some specific genome analyses. Up to now, the performances of assembling repeats of these current assemblers are very poor. Results. To improve this problem, we proposed a new genome assembly algorithm, named SWA, which has four properties: (1) assembling repeats and nonrepeats; (2) adopting a new overlapping extension strategy to extend each seed; (3) adopting sliding window to filter out the sequencing bias; and (4) proposing a compensational mechanism for low coverage datasets. SWA was evaluated and validated in both simulations and real sequencing datasets. The accuracy of assembling repeats and estimating the copy numbers is up to 99% and 100%, respectively. Finally, the extensive comparisons with other eight leading assemblers show that SWA outperformed others in terms of completeness and correctness of assembling repeats and nonrepeats. Conclusions. This paper proposed a new de novo genome assembly method for resolving complex repeats. SWA not only can detect where repeats or nonrepeats are but also can assemble them completely from NGS data, especially for assembling repeats. This is the advantage over other assemblers.
PMCID: PMC4055594  PMID: 24967398
2.  Fine Mapping of qRC10-2, a Quantitative Trait Locus for Cold Tolerance of Rice Roots at Seedling and Mature Stages 
PLoS ONE  2014;9(5):e96046.
Cold stress causes various injuries to rice seedlings in low-temperature and high-altitude areas and is therefore an important factor affecting rice production in such areas. In this study, root conductivity (RC) was used as an indicator to map quantitative trait loci (QTLs) of cold tolerance in Oryza rufipogon Griff., Dongxiang wild rice (DX), at its two-leaf stage. The correlation coefficients between RC and the plant survival rate (PSR) at the seedling and maturity stages were –0.85 and –0.9 (P = 0.01), respectively, indicating that RC is a reliable index for evaluating cold tolerance of rice. A preliminary mapping group was constructed from 151 BC2F1 plants using DX as a cold-tolerant donor and the indica variety Nanjing 11 (NJ) as a recurrent parent. A total of 113 codominant simple-sequence repeat (SSR) markers were developed, with a parental polymorphism of 17.3%. Two cold-tolerant QTLs, named qRC10-1 and qRC10-2 were detected on chromosome 10 by composite interval mapping. qRC10-1 (LOD = 3.1, RM171-RM1108) was mapped at 148.3 cM, and qRC10-2 (LOD = 6.1, RM25570-RM304) was mapped at 163.3 cM, which accounted for 9.4% and 32.1% of phenotypic variances, respectively. To fine map the major locus qRC10-2, NJ was crossed with a BC4F2 plant (L188-3), which only carried the QTL qRC10-2, to construct a large BC5F2 fine-mapping population with 13,324 progenies. Forty-five molecular markers were designed to evenly cover qRC10-2, and 10 markers showed polymorphisms between DX and NJ. As a result, qRC10-2 was delimited to a 48.5-kb region between markers qc45 and qc48. In this region, Os10g0489500 and Os10g0490100 exhibited different expression patterns between DX and NJ. Our results provide a basis for identifying the gene(s) underlying qRC10-2, and the markers developed here may be used to improve low-temperature tolerance of rice seedling and maturity stages via marker-assisted selection (MAS).
Key Message
With root electrical conductivity used as a cold-tolerance index, the quantitative trait locus qRC10-2 was fine mapped to a 48.5-kb candidate region, and Os10g0489500 and Os10g0490100 were identified as differently expressed genes for qRC10-2.
PMCID: PMC4006884  PMID: 24788204
3.  Modified Vaccinia Virus Ankara Triggers Type I IFN Production in Murine Conventional Dendritic Cells via a cGAS/STING-Mediated Cytosolic DNA-Sensing Pathway 
PLoS Pathogens  2014;10(4):e1003989.
Modified vaccinia virus Ankara (MVA) is an attenuated poxvirus that has been engineered as a vaccine against infectious agents and cancers. Our goal is to understand how MVA modulates innate immunity in dendritic cells (DCs), which can provide insights to vaccine design. In this study, using murine bone marrow-derived dendritic cells, we assessed type I interferon (IFN) gene induction and protein secretion in response to MVA infection. We report that MVA infection elicits the production of type I IFN in murine conventional dendritic cells (cDCs), but not in plasmacytoid dendritic cells (pDCs). Transcription factors IRF3 (IFN regulatory factor 3) and IRF7, and the positive feedback loop mediated by IFNAR1 (IFN alpha/beta receptor 1), are required for the induction. MVA induction of type I IFN is fully dependent on STING (stimulator of IFN genes) and the newly discovered cytosolic DNA sensor cGAS (cyclic guanosine monophosphate-adenosine monophosphate synthase). MVA infection of cDCs triggers phosphorylation of TBK1 (Tank-binding kinase 1) and IRF3, which is abolished in the absence of cGAS and STING. Furthermore, intravenous delivery of MVA induces type I IFN in wild-type mice, but not in mice lacking STING or IRF3. Treatment of cDCs with inhibitors of endosomal and lysosomal acidification or the lysosomal enzyme Cathepsin B attenuated MVA-induced type I IFN production, indicating that lysosomal enzymatic processing of virions is important for MVA sensing. Taken together, our results demonstrate a critical role of the cGAS/STING-mediated cytosolic DNA-sensing pathway for type I IFN induction in cDCs by MVA. We present evidence that vaccinia virulence factors E3 and N1 inhibit the activation of IRF3 and the induction of IFNB gene in MVA-infected cDCs.
Author Summary
Modified vaccinia virus Ankara (MVA) is an attenuated vaccinia strain with large deletions of the parental genome that render it non-replicative in mammalian cells. MVA is a safe and effective vaccine against both smallpox and monkeypox. MVA has been investigated as a vaccine vector for infectious diseases and cancers. Dendritic cells (DCs) play important roles in innate and adaptive immunity. A better understanding of how MVA is detected by innate immune sensors in DCs would guide the development of more effective MVA-based vaccines. We report our findings that MVA infection induces the production of type I interferon (IFN) in conventional dendritic cells via a cytosolic DNA-sensing pathway mediated by the newly discovered DNA sensor cGAS, its adaptor STING, and transcription factors IRF3 and IRF7. By contrast, wild-type vaccinia virus fails to activate this pathway. Furthermore, we show that vaccinia virulence factors E3 and N1 play inhibitory roles in the cytosolic DNA-sensing pathway.
PMCID: PMC3990710  PMID: 24743339
4.  Modeling and Computing of Stock Index Forecasting Based on Neural Network and Markov Chain 
The Scientific World Journal  2014;2014:124523.
The stock index reflects the fluctuation of the stock market. For a long time, there have been a lot of researches on the forecast of stock index. However, the traditional method is limited to achieving an ideal precision in the dynamic market due to the influences of many factors such as the economic situation, policy changes, and emergency events. Therefore, the approach based on adaptive modeling and conditional probability transfer causes the new attention of researchers. This paper presents a new forecast method by the combination of improved back-propagation (BP) neural network and Markov chain, as well as its modeling and computing technology. This method includes initial forecasting by improved BP neural network, division of Markov state region, computing of the state transition probability matrix, and the prediction adjustment. Results of the empirical study show that this method can achieve high accuracy in the stock index prediction, and it could provide a good reference for the investment in stock market.
PMCID: PMC3982277  PMID: 24782659
5.  Association of Single Nucleotide Polymorphisms in Estrogen Receptor Alpha Gene with Susceptibility to Knee Osteoarthritis: A Case-Control Study in a Chinese Han Population 
BioMed Research International  2014;2014:151457.
Osteoarthritis (OA) is the most prevalent form of arthritis and its multifactorial nature has been increasingly recognized. Genetic factors play an important role in OA etiology and estrogen receptor alpha (ESR1) gene polymorphisms may be involved. This study tried to explore whether the ESR1 gene single nucleotide polymorphisms (SNPs) were associated with primary knee OA in the Chinese Han population. Two SNPs, rs2234693 and rs9340799, were genotyped in 469 cases and 522 controls. Rs2234693 was associated with knee OA in the dominant genetic model (TT + TC versus CC) (P = 0.025) and a higher T allele frequency existed (P = 0.047) among females. The combined genotype (TT + TC) (P = 0.025) and T allele (P = 0.016) were related with mild knee OA only. For rs9340799, A allele was associated with knee OA in all subjects (P = 0.031) and females (P = 0.046). Statistical differences were detected in the dominant genetic model (AA + AG versus GG) among females (P = 0.030). The combined genotype (AA + AG) (P = 0.036) and A allele (P = 0.039) were merely correlated with mild knee OA. ESR1 gene is considerably associated with knee OA etiology in the Chinese Han population.
PMCID: PMC3977114  PMID: 24772413
6.  A Novel Mutation in the TECTA Gene in a Chinese Family with Autosomal Dominant Nonsyndromic Hearing Loss 
PLoS ONE  2014;9(2):e89240.
TECTA-related deafness can be inherited as autosomal-dominant nonsyndromic deafness (designated DFNA) or as the autosomal-recessive version. The α-tectorin protein, which is encoded by the TECTA gene, is one of the major components of the tectorial membrane in the inner ear. Using targeted DNA capture and massively parallel sequencing (MPS), we screened 42 genes known to be responsible for human deafness in a Chinese family (Family 3187) in which common deafness mutations had been ruled out as the cause, and identified a novel mutation, c.257–262CCTTTC>GCT (p. Ser86Cys; p. Pro88del) in exon 3 of the TECTA gene in the proband and his extended family. All affected individuals in this family had moderate down-sloping hearing loss across all frequencies. To our knowledge, this is the second TECTA mutation identified in Chinese population. This study demonstrates that targeted genomic capture, MPS, and barcode technology might broaden the availability of genetic testing for individuals with undiagnosed DFNA.
PMCID: PMC3931719  PMID: 24586623
7.  PAMAM-Lys, a Novel Vaccine Delivery Vector, Enhances the Protective Effects of the SjC23 DNA Vaccine against Schistosoma japonicum Infection 
PLoS ONE  2014;9(1):e86578.
Schistosomiasis japonica remains a major public-health concern in China. Praziquantel-based chemotherapy effectively reduces both infections and intensity; however, it can not prevent re-infection. Furthermore, there is an increasing concern about praziquantel resistance following long-term repeated use of the drug in endemic areas. Therefore, development of a schistosomiasis vaccine, as a strategy to prevent and control schistosomiasis japonica, has been given high priority. The present study was conducted to develop PAMAM dendrimers as a novel vaccine delivery vector for a schistosomiasis japonica DNA vaccine and evaluate its ability to enhance protective effects against Schistosoma japonicum infection.
Methodology/Principal Findings
Lysine was used to modify 4.0G PAMAM, and the modified product PAMAM-Lys was synthesized. PAMAM-Lys showed both high transfection and low cytotocity for gene delivery in vitro. DNA vaccines combined with PAMAM-Lys produced higher level of protection compare with naked DNA vaccines against S. japonicum infection in a mouse model. Futhermore,antibodies from mice immunized with PAMAM-Lys combined DNA vaccines were significantly higher than those of mice immunized with the naked DNA vaccines. The PAMAM-Lys vector elicited a predominantly IgG2a antibody response and a tremendously increase in the production of IL-2 and IFN-γ.
Lysine-modified PAMAM-Lys is an excellent vector. PAMAM-Lys may enhance the immunoreactivity of DNA vaccine and increase the protective effect of the SjC23 DNA vaccine against S. japonicum infection.
PMCID: PMC3907433  PMID: 24497955
8.  Information Spread of Emergency Events: Path Searching on Social Networks 
The Scientific World Journal  2014;2014:179620.
Emergency has attracted global attentions of government and the public, and it will easily trigger a series of serious social problems if it is not supervised effectively in the dissemination process. In the Internet world, people communicate with each other and form various virtual communities based on social networks, which lead to a complex and fast information spread pattern of emergency events. This paper collects Internet data based on data acquisition and topic detection technology, analyzes the process of information spread on social networks, describes the diffusions and impacts of that information from the perspective of random graph, and finally seeks the key paths through an improved IBF algorithm. Application cases have shown that this algorithm can search the shortest spread paths efficiently, which may help us to guide and control the information dissemination of emergency events on early warning.
PMCID: PMC3926277  PMID: 24600323
9.  Arsenic Trioxide Induces Apoptosis in Human Platelets via C-Jun NH2-Terminal Kinase Activation 
PLoS ONE  2014;9(1):e86445.
Arsenic trioxide (ATO), one of the oldest drugs in both Western and traditional Chinese medicine, has become an effective anticancer drug, especially in the treatment of acute promyelocytic leukemia (APL). However, thrombocytopenia occurred in most of ATO-treated patients with APL or other malignant diseases, and the pathogenesis remains unclear. Here we show that ATO dose-dependently induces depolarization of mitochondrial inner transmembrane potential (ΔΨm), up-regulation of Bax and down-regulation of Bcl-2 and Bcl-XL, caspase-3 activation, and phosphotidylserine (PS) exposure in platelets. ATO did not induce surface expression of P-selectin and PAC-1 binding, whereas, obviously reduced collagen, ADP, and thrombin induced platelet aggregation. ATO dose-dependently induced c-Jun NH2-terminal kinase (JNK) activation, and JNK specific inhibitor dicumarol obviously reduced ATO-induced ΔΨm depolarization in platelets. Clinical therapeutic dosage of ATO was intraperitoneally injected into C57 mice, and the numbers of circulating platelets were significantly reduced after five days of continuous injection. The data demonstrate that ATO induces caspase-dependent apoptosis via JNK activation in platelets. ATO does not incur platelet activation, whereas, it not only impairs platelet function but also reduces circulating platelets in vivo, suggesting the possible pathogenesis of thrombocytopenia in patients treated with ATO.
PMCID: PMC3899281  PMID: 24466103
10.  Complete Genome Sequence of a Novel Pigeon Torque Teno Virus in China 
Genome Announcements  2013;1(6):e01076-13.
Torque teno virus is a nonenveloped single-stranded DNA virus infecting humans and nonprimate species. We report the complete genome sequence of a pigeon torque teno virus isolated from pigeons in Jiangsu Province, China, in 2012. This genome sequence will be useful for viral diagnostics and disease control.
PMCID: PMC3868864  PMID: 24356840
11.  Synonymous Codon Usage in TTSuV2: Analysis and Comparison with TTSuV1 
PLoS ONE  2013;8(11):e81469.
Two species of the DNA virus Torque teno sus virus (TTSuV), TTSuV1 and TTSuV2, have become widely distributed in pig-farming countries in recent years. In this study, we performed a comprehensive analysis of synonymous codon usage bias in 41 available TTSuV2 coding sequences (CDS), and compared the codon usage patterns of TTSuV2 and TTSuV1. TTSuV codon usage patterns were found to be phylogenetically conserved. Values for the effective number of codons (ENC) indicated that the overall extent of codon usage bias in both TTSuV2 and TTSuV1 was not significant, the most frequently occurring codons had an A or C at the third codon position. Correspondence analysis (COA) was performed and TTSuV2 and TTSuV1 sequences were located in different quadrants of the first two major axes. A plot of the ENC revealed that compositional constraint was the major factor determining the codon usage bias for TTSuV2. In addition, hierarchical cluster analysis of 41 TTSuV2 isolates based on relative synonymous codon usage (RSCU) values suggested that there was no association between geographic distribution and codon bias of TTSuV2 sequences. Finally, the comparison of RSCU for TTSuV2, TTSuV1 and the corresponding host sequence indicated that the codon usage pattern of TTSuV2 was similar to that of TTSuV1. However the similarity was low for each virus and its host. These conclusions provide important insight into the synonymous codon usage pattern of TTSuV2, as well as better understangding of the molecular evolution of TTSuV2 genomes.
PMCID: PMC3841265  PMID: 24303050
12.  Three-dimensional culture may promote cell reprogramming 
Organogenesis  2013;9(2):118-120.
Stem cells reside in stem cells niches, which maintain the balance of self-renewal and differentiation of stem cells. In stem cell niches, cell-cell, cell-extracellular matrix interactions and diffusible signals are important elements. However, another pivotal element is that localized and diffusible signals are all organized as three-dimensional (3-D) structures, which is easily neglected by in vitro cell biology research. Under 3-D culture conditions, the morphology of cells exhibited differently from cultured in traditional two-dimensional (2-D) conditions. Under 3-D culture conditions, the self-renewal and pluripotency of neural stem cells (NSCs) and bone marrow mesenchymal stem cells (BMSCs) were enhanced compared with culturing under 2-D conditions. 3-D cultures could change the transcriptional profile of NSCs compared with 2-D cultures. We hypothesized that 3-D cultures could reprogram mature cells such as fibroblasts to an immature state, like the pluripotent stem cells. The primary results indicated that several ES marker genes were upregulated by 3-D cultures. Though further experiments are needed, this work may provide a method of reprogramming mature cells without gene modifications.
PMCID: PMC3812285  PMID: 23820263
stem cell niches; three-dimensional culture; stem cells; stemness; reprogramming
13.  Weighted SNP Set Analysis in Genome-Wide Association Study 
PLoS ONE  2013;8(9):e75897.
Genome-wide association studies (GWAS) are popular for identifying genetic variants which are associated with disease risk. Many approaches have been proposed to test multiple single nucleotide polymorphisms (SNPs) in a region simultaneously which considering disadvantages of methods in single locus association analysis. Kernel machine based SNP set analysis is more powerful than single locus analysis, which borrows information from SNPs correlated with causal or tag SNPs. Four types of kernel machine functions and principal component based approach (PCA) were also compared. However, given the loss of power caused by low minor allele frequencies (MAF), we conducted an extension work on PCA and used a new method called weighted PCA (wPCA). Comparative analysis was performed for weighted principal component analysis (wPCA), logistic kernel machine based test (LKM) and principal component analysis (PCA) based on SNP set in the case of different minor allele frequencies (MAF) and linkage disequilibrium (LD) structures. We also applied the three methods to analyze two SNP sets extracted from a real GWAS dataset of non-small cell lung cancer in Han Chinese population. Simulation results show that when the MAF of the causal SNP is low, weighted principal component and weighted IBS are more powerful than PCA and other kernel machine functions at different LD structures and different numbers of causal SNPs. Application of the three methods to a real GWAS dataset indicates that wPCA and wIBS have better performance than the linear kernel, IBS kernel and PCA.
PMCID: PMC3786949  PMID: 24098741
14.  Proteotoxic stress of cancer: implication of the heat-shock response in oncogenesis 
Journal of cellular physiology  2012;227(8):2982-2987.
Organisms frequently encounter a wide variety of proteotoxic stressors. The heat-shock response, an ancient cytoprotective mechanism, has evolved to augment organismal survival and longevity in the face of proteotoxic stress from without and within. These broadly recognized beneficial effects, ironically, contrast sharply with its emerging role as a culprit in the pathogenesis of cancers. Here, we present an overview of the normal biology of the heat-shock response and highlight its implications in oncogenic processes, including the proteotoxic stress phenotype of cancer; the function of this stress response in helping cancer survive and adapt to proteotoxic stress; and perturbation of proteome homeostasis in cancer as a potential therapeutic avenue.
PMCID: PMC3431153  PMID: 22105155
Oncogenesis; Proteotoxic stress; Heat-shock response; HSF1
15.  BGDB: a database of bivalent genes 
Bivalent gene is a gene marked with both H3K4me3 and H3K27me3 epigenetic modification in the same area, and is proposed to play a pivotal role related to pluripotency in embryonic stem (ES) cells. Identification of these bivalent genes and understanding their functions are important for further research of lineage specification and embryo development. So far, lots of genome-wide histone modification data were generated in mouse and human ES cells. These valuable data make it possible to identify bivalent genes, but no comprehensive data repositories or analysis tools are available for bivalent genes currently. In this work, we develop BGDB, the database of bivalent genes. The database contains 6897 bivalent genes in human and mouse ES cells, which are manually collected from scientific literature. Each entry contains curated information, including genomic context, sequences, gene ontology and other relevant information. The web services of BGDB database were implemented with PHP + MySQL + JavaScript, and provide diverse query functions.
Database URL:
PMCID: PMC3724367  PMID: 23894186
16.  Expression of SET Protein in the Ovaries of Patients with Polycystic Ovary Syndrome 
Background. We previously found that expression of SET gene was up-regulated in polycystic ovaries by using microarray. It suggested that SET may be an attractive candidate regulator involved in the pathophysiology of polycystic ovary syndrome (PCOS). In this study, expression and cellular localization of SET protein were investigated in human polycystic and normal ovaries. Method. Ovarian tissues, six normal ovaries and six polycystic ovaries, were collected during transsexual operation and surgical treatment with the signed consent form. The cellular localization of SET protein was observed by immunohistochemistry. The expression levels of SET protein were analyzed by Western Blot. Result. SET protein was expressed predominantly in the theca cells and oocytes of human ovarian follicles in both PCOS ovarian tissues and normal ovarian tissues. The level of SET protein expression in polycystic ovaries was triple higher than that in normal ovaries (P < 0.05). Conclusion. SET was overexpressed in polycystic ovaries more than that in normal ovaries. Combined with its localization in theca cells, SET may participate in regulating ovarian androgen biosynthesis and the pathophysiology of hyperandrogenism in PCOS.
PMCID: PMC3686144  PMID: 23861679
17.  Susceptibility Weighted Imaging: A New Tool in the Diagnosis of Prostate Cancer and Detection of Prostatic Calcification 
PLoS ONE  2013;8(1):e53237.
Susceptibility weighted imaging (SWI) is a new MRI technique which has been proved very useful in the diagnosis of brain diseases, but few study was performed on its value in prostatic diseases. The aim of the present study was to investigate the value of SWI in distinguishing prostate cancer from benign prostatic hyperplasia and detecting prostatic calcification.
Methodology/Principal Findings
23 patients with prostate cancer and 53 patients with benign prostatic hyperplasia proved by prostate biopsy were scanned on a 3.0T MR and a 16-row CT scanner. High-resolution SWI, conventional MRI and CT were performed on all patients. The MRI and CT findings, especially SWI, were analyzed and compared. The analyses revealed that 19 out of 23 patients with prostate cancer presented hemorrhage within tumor area on SWI. However, in 53 patients with benign prostatic hyperplasia, hemorrhage was detected only in 1 patient in prostate by SWI. When comparing SWI, conventional MRI and CT in detecting prostate cancer hemorrhage, out of the 19 patients with prostate cancer who had prostatic hemorrhage detected by SWI, the prostatic hemorrhage was detected in only 7 patients by using conventional MRI, and none was detected by CT. In addition, CT demonstrated calcifications in 22 patients which were all detected by SWI whereas only 3 were detected by conventional MRI. Compared to CT, SWI showed 100% in the diagnostic sensitivity, specificity, accuracy, positive predictive value(PPV) and negative predictive value(NPV) in detecting calcifications in prostate but conventional MRI demonstrated 13.6% in sensitivity, 100% in specificity, 75% in accuracy, 100% in PPV and 74% in NPV.
More apparent prostate hemorrhages were detected on SWI than on conventional MRI or CT. SWI may provide valuable information for the differential diagnosis between prostate cancer and prostatic hyperplasia. Filtered phase images can identify prostatic calcifications as well as CT.
PMCID: PMC3538770  PMID: 23308170
18.  miR-146a, an IL-1β responsive miRNA, induces vascular endothelial growth factor and chondrocyte apoptosis by targeting Smad4 
miR-146a is one of the first identified miRNAs expressed differentially in osteoarthritis (OA) cartilage. However, the role it plays in OA pathogenesis is not clear. The aim of this study is to identify a molecular target of miR-146a, thereby elucidating its function in chondrocytes during OA pathogenesis.
Primary chondrocytes from Sprague-Dawley rats were treated with IL-1β before the expression levels of miR-146a, Smad4 and vascular endothelial growth factor (VEGF) were quantified by real-time PCR and/or western blotting. The effect of miR-146a on cellular response to transforming growth factor (TGF)-β1 was quantified by a luciferase reporter harboring TGF-β1 responsive elements and by extracellular signal-regulated kinase assay. The effect of miR-146a on apoptosis was quantified by the TUNEL assay. OA pathogenesis was surgically induced with joint instability in rats, evaluated by histopathological analysis with safranin O staining, and the expression levels of miR-146a, Smad4, and VEGF were quantified using real-time PCR and/or immunohistochemistry.
IL-1β treatment of chondrocytes increased the expression levels of miR-146a and VEGF and decreased the levels of Smad4 in a time-dependent manner. miR-146a upregulated VEGF expression and downregulated Smad4 expression in chondrocytes, while a miR-146a inhibitor acted in a converse manner. Smad4, a common mediator of the TGF-β pathway, is identified as a direct target of miR-146a by harboring a miR-146a binding sequence in the 3'-UTR region of its mRNA. Mutation of the binding sequence significantly relieved the inhibition of the Smad4 reporter activity by miR-146a. Furthermore, miR-146a upregulation of VEGF is mediated by Smad4. Expression of miR-146a led to a reduction of cellular responsiveness to TGF-β and an increase of apoptosis rate in chondrocytes. In vivo, cartilage from surgically induced OA rats displayed higher levels of miR-146a and VEGF compared with the sham group. In contrast, Smad4 expression level was lower in the OA group than the sham group.
IL-1β responsive miR-146a is overexpressed in an experimentally induced OA model, accompanied by upregulation of VEGF and downregulation of Smad4 in vivo. miR-146a may contribute to OA pathogenesis by increasing VEGF levels and by impairing the TGF-β signaling pathway through targeted inhibition of Smad4 in cartilage.
PMCID: PMC3446449  PMID: 22507670
19.  Novel optoelectronic devices based on single semiconductor nanowires (nanobelts) 
Nanoscale Research Letters  2012;7(1):218.
Semiconductor nanowires (NWs) or nanobelts (NBs) have attracted more and more attention due to their potential application in novel optoelectronic devices. In this review, we present our recent work on novel NB photodetectors, where a three-terminal metal–semiconductor field-effect transistor (MESFET) device structure was exploited. In contrast to the common two-terminal NB (NW) photodetectors, the MESFET-based photodetector can make a balance among overall performance parameters, which is desired for practical device applications. We also present our recent work on graphene nanoribbon/semiconductor NW (SNW) heterojunction light-emitting diodes (LEDs). Herein, by taking advantage of both graphene and SNWs, we have fabricated, for the first time, the graphene-based nano-LEDs. This achievement opens a new avenue for developing graphene-based nano-electroluminescence devices. Moreover, the novel graphene/SNW hybrid devices can also find use in other applications, such as high-sensitivity sensor and transparent flexible devices in the future.
PMCID: PMC3443073  PMID: 22501032
Schottky junction; Graphene; Nanowires; Nanobelts; Optoelectronics
20.  Polysaccharides from the Medicinal Mushroom Cordyceps taii Show Antioxidant and Immunoenhancing Activities in a D-Galactose-Induced Aging Mouse Model 
Cordyceps taii, an edible medicinal mushroom native to south China, is recognized as an unparalleled resource of healthy foods and drug discovery. In the present study, the antioxidant pharmacological properties of C. taii were systematically investigated. In vitro assays revealed the scavenging activities of the aqueous extract and polysaccharides of C. taii against various free radicals, that is, 1,1-diphenyl-2-picrylhydrazyl radical, hydroxyl radical, and superoxide anion radical. The EC50 values for superoxide anion-free radical ranged from 2.04 mg/mL to 2.49 mg/mL, which was at least 2.6-fold stronger than that of antioxidant thiourea. The polysaccharides also significantly enhanced the antioxidant enzyme activities (superoxide dismutase, catalase, and glutathione peroxidase) and markedly decreased the malondialdehyde production of lipid peroxidation in a D-galactose-induced aging mouse model. Interestingly, the immune function of the administration group was significantly boosted compared with the D-galactose-induced aging model group. Therefore, the C. taii polysaccharides possessed potent antioxidant activity closely associated with immune function enhancement and free radical scavenging. These findings suggest that the polysaccharides are a promising source of natural antioxidants and antiaging drugs. Consequently, a preliminary chemical investigation was performed using gas chromatography-mass spectroscopy and revealed that the polysaccharides studied were mainly composed of glucose, mannose, and galactose. Fourier-transform infrared spectra also showed characteristic polysaccharide absorption bands.
PMCID: PMC3321445  PMID: 22536281
21.  Causality Analysis of Neural Connectivity: Critical Examination of Existing Methods and Advances of New Methods 
Granger causality (GC) is one of the most popular measures to reveal causality influence of time series and has been widely applied in economics and neuroscience. Especially, its counterpart in frequency domain, spectral GC, as well as other Granger-like causality measures have recently been applied to study causal interactions between brain areas in different frequency ranges during cognitive and perceptual tasks. In this paper, we show that: 1) GC in time domain cannot correctly determine how strongly one time series influences the other when there is directional causality between two time series, and 2) spectral GC and other Granger-like causality measures have inherent shortcomings and/or limitations because of the use of the transfer function (or its inverse matrix) and partial information of the linear regression model. On the other hand, we propose two novel causality measures (in time and frequency domains) for the linear regression model, called new causality and new spectral causality, respectively, which are more reasonable and understandable than GC or Granger-like measures. Especially, from one simple example, we point out that, in time domain, both new causality and GC adopt the concept of proportion, but they are defined on two different equations where one equation (for GC) is only part of the other (for new causality), thus the new causality is a natural extension of GC and has a sound conceptual/theoretical basis, and GC is not the desired causal influence at all. By several examples, we confirm that new causality measures have distinct advantages over GC or Granger-like measures. Finally, we conduct event-related potential causality analysis for a subject with intracranial depth electrodes undergoing evaluation for epilepsy surgery, and show that, in the frequency domain, all measures reveal significant directional event-related causality, but the result from new spectral causality is consistent with event-related time–frequency power spectrum activity. The spectral GC as well as other Granger-like measures are shown to generate misleading results. The proposed new causality measures may have wide potential applications in economics and neuroscience.
PMCID: PMC3281296  PMID: 21511564
Event-related potential; Granger or Granger-like causality; linear regression model; new causality; power spectrum
22.  Absence of the Adenosine A2A Receptor Confers Pulmonary Arterial Hypertension and Increased Pulmonary Vascular Remodeling in Mice 
Journal of Vascular Research  2010;48(2):171-183.
Pulmonary arterial hypertension (PAH) is characterized by sustained elevation of pulmonary vascular resistance resulting from endothelial and smooth muscle cell dysfunction and collagen deposition in pulmonary vascular walls. In this study, we investigated the role of the adenosine A2A receptor (A2AR) in the development of PAH by determining the effect of genetic inactivation of A2ARs on pulmonary vascular remodeling in mice.
Methods and Results
We characterized hemodynamic, histological and ultrastructural changes in pulmonary vascular remodeling in A2AR knockout (KO) mice compared with their wild-type (WT) littermates after exposure to normoxia and hypoxic conditions. After exposure to normoxia, compared to WT mice, A2AR KO mice displayed: (1) increased right ventricular systolic pressures and an elevated ratio of the right ventricle over left ventricle plus septum (Fulton index), (2) increased wall area and thickness as well as enhanced smooth muscle actin immunoreactivity in pulmonary resistance vessels, (3) increased proliferating cell nuclear antigen-positive cells in pulmonary resistance vessels and (4) increased smooth muscle cells hypertrophy and collagen deposition in the adventitia of pulmonary arteriole walls as revealed by electron microscope. By contrast, histological analysis revealed no features of hypertensive nephropathy in A2AR KO mice and there was no significant difference in systemic blood pressure, and left ventricular masses among the 3 genotypes. Furthermore, following chronic exposure to hypoxia, A2AR KO mice exhibited exacerbated elevation in right ventricular systolic pressure, hypertrophy of pulmonary resistance vessels and increased cell proliferation in pulmonary resistance vessels, compared to WT littermates. Thus, genetic inactivation of A2ARs selectively produced PAH and associated increased smooth muscle proliferation and collagen deposition.
Extracellular adenosine acting at A2ARs represents an important regulatory mechanism to control the development of PAH and pulmonary vascular remodeling.
PMCID: PMC2975736  PMID: 20938208
Adenosine A2A receptor; Collagen hyperplasia; Pulmonary arterial hypertension; Pulmonary vascular remodeling; Smooth muscle hypertrophy
23.  Endoplasmic reticulum stress mediating downregulated StAR and 3-beta-HSD and low plasma testosterone caused by hypoxia is attenuated by CPU86017-RS and nifedipine 
Hypoxia exposure initiates low serum testosterone levels that could be attributed to downregulated androgen biosynthesizing genes such as StAR (steroidogenic acute regulatory protein) and 3-beta-HSD (3-beta-hydroxysteroid dehydrogenase) in the testis. It was hypothesized that these abnormalities in the testis by hypoxia are associated with oxidative stress and an increase in chaperones of endoplasmic reticulum stress (ER stress) and ER stress could be modulated by a reduction in calcium influx. Therefore, we verify that if an application of CPU86017-RS (simplified as RS, a derivative to berberine) could alleviate the ER stress and depressed gene expressions of StAR and 3-beta-HSD, and low plasma testosterone in hypoxic rats, these were compared with those of nifedipine.
Adult male Sprague-Dawley rats were randomly divided into control, hypoxia for 28 days, and hypoxia treated (mg/kg, p.o.) during the last 14 days with nifedipine (Nif, 10) and three doses of RS (20, 40, 80), and normal rats treated with RS isomer (80). Serum testosterone (T) and luteinizing hormone (LH) were measured. The testicular expressions of biomarkers including StAR, 3-beta-HSD, immunoglobulin heavy chain binding protein (Bip), double-strand RNA-activated protein kinase-like ER kinase (PERK) and pro-apoptotic transcription factor C/EBP homologous protein (CHOP) were measured.
In hypoxic rats, serum testosterone levels decreased and mRNA and protein expressions of the testosterone biosynthesis related genes, StAR and 3-beta-HSD were downregulated. These changes were linked to an increase in oxidants and upregulated ER stress chaperones: Bip, PERK, CHOP and distorted histological structure of the seminiferous tubules in the testis. These abnormalities were attenuated significantly by CPU86017-RS and nifedipine.
Downregulated StAR and 3-beta-HSD significantly contribute to low testosterone in hypoxic rats and is associated with ER stress which mediates testis damage caused by oxygen deprivation. CPU86017-RS is potential in ameliorating hypoxia-induced testicular injuries, possibly by its calcium antagonist effects on the testis.
PMCID: PMC3276427  PMID: 22226148
ER stress; testosterone; hypoxia; StAR; 3-beta-HSD; CHOP; PERK; Bip; testes; CPU86017
24.  Classification of ADHD children through multimodal magnetic resonance imaging 
Attention deficit/hyperactivity disorder (ADHD) is one of the most common diseases in school-age children. To date, the diagnosis of ADHD is mainly subjective and studies of objective diagnostic method are of great importance. Although many efforts have been made recently to investigate the use of structural and functional brain images for the diagnosis purpose, few of them are related to ADHD. In this paper, we introduce an automatic classification framework based on brain imaging features of ADHD patients and present in detail the feature extraction, feature selection, and classifier training methods. The effects of using different features are compared against each other. In addition, we integrate multimodal image features using multi-kernel learning (MKL). The performance of our framework has been validated in the ADHD-200 Global Competition, which is a world-wide classification contest on the ADHD-200 datasets. In this competition, our classification framework using features of resting-state functional connectivity (FC) was ranked the 6th out of 21 participants under the competition scoring policy and performed the best in terms of sensitivity and J-statistic.
PMCID: PMC3432508  PMID: 22969710
attention deficit/hyperactivity disorder; ADHD-200 competition; resting-state functional connectivity; support vector machine; multi-kernel learning
25.  Promoting Long-Term Survival of Insulin-Producing Cell Grafts That Differentiate from Adipose Tissue-Derived Stem Cells to Cure Type 1 Diabetes 
PLoS ONE  2011;6(12):e29706.
Insulin-producing cell clusters (IPCCs) have recently been generated in vitro from adipose tissue-derived stem cells (ASCs) to circumvent islet shortage. However, it is unknown how long they can survive upon transplantation, whether they are eventually rejected by recipients, and how their long-term survival can be induced to permanently cure type 1 diabetes. IPCC graft survival is critical for their clinical application and this issue must be systematically addressed prior to their in-depth clinical trials.
Methodology/Principal Findings
Here we found that IPCC grafts that differentiated from murine ASCs in vitro, unlike their freshly isolated islet counterparts, did not survive long-term in syngeneic mice, suggesting that ASC-derived IPCCs have intrinsic survival disadvantage over freshly isolated islets. Indeed, β cells retrieved from IPCC syngrafts underwent faster apoptosis than their islet counterparts. However, blocking both Fas and TNF receptor death pathways inhibited their apoptosis and restored their long-term survival in syngeneic recipients. Furthermore, blocking CD40-CD154 costimulation and Fas/TNF signaling induced long-term IPCC allograft survival in overwhelming majority of recipients. Importantly, Fas-deficient IPCC allografts exhibited certain immune privilege and enjoyed long-term survival in diabetic NOD mice in the presence of CD28/CD40 joint blockade while their islet counterparts failed to do so.
Long-term survival of ASC-derived IPCC syngeneic grafts requires blocking Fas and TNF death pathways, whereas blocking both death pathways and CD28/CD40 costimulation is needed for long-term IPCC allograft survival in diabetic NOD mice. Our studies have important clinical implications for treating type 1 diabetes via ASC-derived IPCC transplantation.
PMCID: PMC3247284  PMID: 22216347

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