Search tips
Search criteria

Results 1-25 (190)

Clipboard (0)

Select a Filter Below

more »
Year of Publication
more »
1.  Iron Oxide Nanoparticle Encapsulated Diatoms for Magnetic Delivery of Small Molecules to Tumors 
Nanoscale  2014;6(4):2073-2076.
Small molecules can be co-loaded with iron oxide nanoparticles onto diatoms. With an external magnetic field, the diatoms, after systemic administration, can be attracted to tumors. This study suggests a great potential of diatoms as a novel and powerful therapeutic vehicle.
PMCID: PMC3974590  PMID: 24424277
2.  Anti-diabetic activity of insulin-degrading enzyme inhibitors mediated by multiple hormones 
Nature  2014;511(7507):94-98.
Despite decades of speculation that inhibiting endogenous insulin degradation might treat type-2 diabetes1, 2, and the identification of IDE (insulin-degrading enzyme) as a diabetes susceptibility gene3, 4, the relationship between the activity of the zinc metalloprotein IDE and glucose homeostasis remains unclear. Although Ide−/− mice have elevated insulin levels, they exhibit impaired, rather than improved, glucose tolerance that may arise from compensatory insulin signalling dysfunction5, 6. IDE inhibitors that are active in vivo are therefore needed to elucidate IDE’s physiological roles and to determine its potential to serve as a target for the treatment of diabetes. Here we report the discovery of a physiologically active IDE inhibitor identified from a DNA-templated macrocycle library. An X-ray structure of the macrocycle bound to IDE reveals that it engages a binding pocket away from the catalytic site, which explains its remarkable selectivity. Treatment of lean and obese mice with this inhibitor shows that IDE regulates the abundance and signalling of glucagon and amylin, in addition to that of insulin. Under physiological conditions that augment insulin and amylin levels, such as oral glucose administration, acute IDE inhibition leads to substantially improved glucose tolerance and slower gastric emptying. These findings demonstrate the feasibility of modulating IDE activity as a new therapeutic strategy to treat type-2 diabetes and expand our understanding of the roles of IDE in glucose and hormone regulation.
PMCID: PMC4142213  PMID: 24847884
3.  Therapeutic targeting of GSK3β enhances the Nrf2 antioxidant response and confers hepatic cytoprotection in hepatitis C 
Gut  2014;64(1):168-179.
Impaired adaptive response to oxidative injuries is a fundamental mechanism central to the pathogenesis of chronic hepatitis C (CHC). Glycogen synthase kinase (GSK) 3β is an indispensable regulator of the oxidative stress response. However, the exact role of GSK3β in CHC is uncertain and was examined.
GSK3β and Nrf2 signaling pathways were examined in JFH1 hepatitis C virus (HCV) infected Huh 7.5.1 hepatocytes and also in liver biopsy specimens from CHC patients.
HCV infection elicited prominent Nrf2 antioxidant response in hepatocytes, marked by elevated expression of the Nrf2 dependent molecule heme oxygenase-1 and subsequent protection from apoptotic cell death. Inhibitory phosphorylation of GSK3β seems to be essential and sufficient for HCV induced Nrf2 response. Mechanistically, GSK3β physically associated and interacted with Nrf2 in hepatocytes. In silico analysis revealed that Nrf2 encompasses multiple GSK3β phosphorylation consensus motifs, denoting Nrf2 as a cognate substrate of GSK3β. In the presence of TGFβ1, the HCV induced GSK3β phosphorylation was blunted via a protein phosphatase 1-dependent mechanism and the cytoprotective Nrf2 response drastically impaired. Lithium, a selective inhibitor of GSK3β, counteracted the effects of TGFβ1. In liver biopsy specimens from CHC patients, the expression of phosphorylated GSK3β positively correlated with Nrf2 expression and was inversely associated with the degree of liver injury. Moreover, CHC patients who received long-term lithium carbonate therapy primarily for concomitant psychiatric disorders exhibited much less liver injury, associated with enhanced hepatic expression of Nrf2.
Inhibition of GSK3β exerts hepatoprotection in CHC possibly through its direct regulation of Nrf2 antioxidant response.
PMCID: PMC4263291  PMID: 24811996
glycogen synthase kinase 3β; chronic hepatitis C; NF-E2 related factor-2; transformation growth factor β1; antioxidant response
4.  Differential urinary specific gravity as a molecular phenotype of the bladder cancer genetic association in the urea transporter gene, SLC14A1 
Genome-wide association studies (GWAS) identified associations between markers within the solute carrier family 14 (urea transporter), member 1 (SLC14A1) gene and risk of bladder cancer. SLC14A1 defines the Kidd blood groups in erythrocytes and is also involved in concentration of the urine in the kidney. We evaluated the association between a representative genetic variant (rs10775480) of SLC14A1 and urine concentration, as measured by urinary specific gravity (USG), in a subset of 275 population-based controls enrolled in the New England Bladder Cancer Study. Overnight urine samples were collected and USG was measured using refractometry. Analysis of covariance was used to estimate adjusted least square means for USG in relation to rs10775480. We also examined the mRNA expression of both urea transporters, SLC14A1 and SLC14A2, in a panel of human tissues. USG was decreased with each copy of the rs10775480 risk T allele (p-trend= 0.011) with a significant difference observed for CC vs. TT genotypes (p-valuetukey=0.024). RNA-sequencing in the bladder tissue showed high expression of SLC14A1 and the absence of SLC14A2, while both transporters were expressed in the kidney. We suggest that the molecular phenotype of this GWAS finding is the genotype-specific biological activity of SLC14A1 in the bladder tissue. Our data suggest that SLC14A1 could be a unique urea transporter in the bladder that has the ability to influence urine concentration and that this mechanism might explain the increased bladder cancer susceptibility associated with rs10775480.
PMCID: PMC3797230  PMID: 23754249
Bladder Cancer; Urinary Specific Gravity; Genome-wide association study; Epidemiology
5.  Independent stem cell lineages regulate adipose organogenesis and adipose homeostasis 
Cell reports  2014;9(3):1007-1022.
Adipose tissues have striking plasticity, highlighted by childhood and adult obesity. Using adipose lineage analyses, smooth muscle actin (SMA)-mural cell fate mapping, and conditional PPARγ deletion to block adipocyte differentiation, we find two phases of adipocyte generation that emanate from two independent adipose progenitor compartments, Developmental and Adult. These two compartments are sequentially required for organ formation and maintenance. Although both Developmental and Adult progenitors are specified during the developmental period and express PPARγ, they have distinct micro-anatomical, functional, morphogenetic and molecular profiles. Further, the two compartments derive from different lineages, while adult adipose progenitors fate map from an SMA+ mural lineage, Developmental progenitors do not. Remarkably, the Adult progenitor compartment appears to be specified earlier than the Developmental cells, and then enters the already developmentally formed adipose depots. Thus, two distinct cell compartments control adipose organ development and organ homeostasis, which may provide discrete therapeutic target for childhood and adult obesity.
PMCID: PMC4250841  PMID: 25437556
6.  Production, Characterization, and Flocculation Mechanism of Cation Independent, pH Tolerant, and Thermally Stable Bioflocculant from Enterobacter sp. ETH-2 
PLoS ONE  2014;9(12):e114591.
Synthetic high polymer flocculants, frequently utilized for flocculating efficiency and low cost, recently have been discovered as producing increased risk to human health and the environment. Development of a more efficient and environmentally sound alternative flocculant agent is investigated in this paper. Bioflocculants are produced by microorganisms and may exhibit a high rate of flocculation activity. The bioflocculant ETH-2, with high flocculating activity (2849 mg Kaolin particle/mg ETH-2), produced by strain Enterobacter sp. isolated from activated sludge, was systematically investigated with regard to its production, characterization, and flocculation mechanism. Analyses of microscopic observation, zeta potential and ETH-2 structure demonstrates the bridging mechanism, as opposed to charge neutralization, was responsible for flocculation of the ETH-2. ETH-2 retains high molecular weight (603 to 1820 kDa) and multi-functional groups (hydroxyl, amide and carboxyl) that contributed to flocculation. Polysaccharides mainly composed of mannose, glucose, and galactose, with a molar ratio of 1∶2.9∶9.8 were identified as the active constituents in bioflocculant. The structure of the long backbone with active sites of polysaccharides was determined as a primary basis for the high flocculation activity. Bioflocculant ETH-2 is cation independent, pH tolerant, and thermally stable, suggesting a potential fit for industrial application.
PMCID: PMC4259340  PMID: 25485629
7.  Identification of Two Missense Mutations of ERCC6 in Three Chinese Sisters with Cockayne Syndrome by Whole Exome Sequencing 
PLoS ONE  2014;9(12):e113914.
Cockayne syndrome (CS) is a rare autosomal recessive disorder, the primary manifestations of which are poor growth and neurologic abnormality. Mutations of the ERCC6 and ERCC8 genes are the predominant cause of Cockayne syndrome, and the ERCC6 gene mutation is present in approximately 65% of cases. The present report describes a case of Cockayne syndrome in a Chinese family, with the patients carrying two missense mutations (c.1595A>G, p.Asp532Gly and c.1607T>G, p.Leu536Trp) in the ERCC6 gene in an apparently compound heterozygote status, especially, p.Asp532Gly has never been reported. The compound heterozygote mutation was found in three patients in the family using whole exome sequencing. The patients’ father and mother carried a heterozygous allele at different locations of the ERCC6 gene, which was confirmed by Sanger DNA sequencing. The two mutations are both located in the highly conserved motif I of ATP-binding helicase and are considered “Damaging,” “Probably Damaging,” “Disease Causing,” and “Conserved”, indicating the role of DNA damage in the pathogenetic process of the disease. The results not only enrich the ERCC6 mutations database, but also indicate that whole exome sequencing will be a powerful tool for discovering the disease causing mutations in clinical diagnosis.
PMCID: PMC4252064  PMID: 25463447
8.  Rab18 Facilitates Dengue Virus Infection by Targeting Fatty Acid Synthase to Sites of Viral Replication 
Journal of Virology  2014;88(12):6793-6804.
Positive-sense RNA viruses, such as dengue virus (DENV), hijack the intracellular membrane machinery for their own replication. The Rab18 protein, a member of the Rab GTPase family, key regulators of membrane trafficking, is located on the organelles involved in DENV infection, such as the endoplasmic reticulum (ER) and lipid droplets (LDs). In this study, we addressed the potential involvement of Rab18 in DENV infection by using cells overexpressing the wild-type, GTP-bound active form, or GDP-bound inactive form of Rab18 and cells with Rab18 knockdown. DENV replication, measured by viral protein, viral RNA, and viral progeny production, as well as LD induction, was reduced in cells with inactive Rab18 and in cells deprived of Rab18 expression, suggesting a positive role of Rab18 in the DENV life cycle. Interestingly, the interaction of fatty acid synthase (FASN), a key lipogenic enzyme in lipid biosynthesis, with DENV NS3 protein relied on the conversion of the GDP-bound to the GTP-bound form of Rab18. Furthermore, the targeting of FASN to sites participating in DENV infection, such as the ER and LDs, depends on functional Rab18. Thus, Rab18-mediated membrane trafficking of FASN and NS3 facilitates DENV replication, probably by ensuring a sufficient and coordinated lipid supply for membrane proliferation and arrangement.
IMPORTANCE Infection by dengue virus (DENV), an important mosquito-borne virus threatening ∼40% of the world's population, can cause mild dengue fever or severe dengue hemorrhagic fever and dengue shock syndrome. The pathogenesis mechanisms of DENV-related diseases are not clear, but high viral replication is believed to be a risk factor for the severe form of DENV infection. Thus, understanding the detailed mechanism of DENV replication might help address this devastating virus. Here, we found that Rab18, a small GTPase involved in vesicle trafficking and located in the endoplasmic reticulum network and on the surfaces of lipid droplets, positively regulates DENV replication. The functional machinery of Rab18 is required to recruit the enzyme fatty acid synthase to sites of DENV replication and to interact with DENV NS3 protein to promote fatty acid biosynthesis. Thus, DENV usurps Rab18 to facilitate its own replication.
PMCID: PMC4054357  PMID: 24696471
9.  The Connectome Visualization Utility: Software for Visualization of Human Brain Networks 
PLoS ONE  2014;9(12):e113838.
In analysis of the human connectome, the connectivity of the human brain is collected from multiple imaging modalities and analyzed using graph theoretical techniques. The dimensionality of human connectivity data is high, and making sense of the complex networks in connectomics requires sophisticated visualization and analysis software. The current availability of software packages to analyze the human connectome is limited. The Connectome Visualization Utility (CVU) is a new software package designed for the visualization and network analysis of human brain networks. CVU complements existing software packages by offering expanded interactive analysis and advanced visualization features, including the automated visualization of networks in three different complementary styles and features the special visualization of scalar graph theoretical properties and modular structure. By decoupling the process of network creation from network visualization and analysis, we ensure that CVU can visualize networks from any imaging modality. CVU offers a graphical user interface, interactive scripting, and represents data uses transparent neuroimaging and matrix-based file types rather than opaque application-specific file formats.
PMCID: PMC4250035  PMID: 25437873
11.  Chronic progressive external ophthalmoplegia with inflammatory myopathy 
Chronic progressive external ophthalmoplegia is one of mitochondrial disorders, characterized by ptosis, limitation of eye movement, variably severe bulbar muscle weakness and proximal limb weakness. Chronic progressive external ophthalmoplegia complicated with acquired disease is extremely rare. We report a 44 years old male patient with more than 20 years of chronic progressive bilateral ptosis and limitation of eye movements manifested dysarthria, dysphagia and neck muscle weakness for 3 years. The first muscle biopsy showed red-ragged fibers and cytochrome c oxidase negative fibers as well as inflammatory cells infiltration. Electron microscopy revealed paracrystalline inclusions. Mitochondrial genetic analysis demonstrated a large-scale mtDNA deletion of m.8470_13446del4977. The patient was treated with prednisone. In a three-year follow-up study, the second biopsy was performed. Before the treatment, except bilateral ptosis and external ophthalmopelgia, this patient presented bulbar muscle weakness and neck muscle weakness. After treated with prednisone, the symptoms of dysphagia, dysarthria and neck muscle weakness were significantly improved, and the second biopsy showed only mitochondrial myopathy pathology but the inflammations disappeared. Here, we report a patient with chronic progressive external ophthalmoplegia complicated with inflammatory myopathy and after treated with prednisone as myositis, he had a significant therapeutic effect.
PMCID: PMC4314000
Chronic progressive external ophthalmoplegia; mitochondrial DNA deletions; inflammatory myopathy
12.  PGRN protects against colitis progression in mice in an IL-10 and TNFR2 dependent manner 
Scientific Reports  2014;4:7023.
This study was aimed to determine the role and regulation of progranulin (PGRN) in the pathogenesis of inflammatory bowel diseases (IBD). Dextran sulfate sodium (DSS)−, picrylsulfonic acid (TNBS)-induced, bone marrow chimera and CD4+CD45Rbhi T cell transfer colitis model were established and analyzed in wild-type and several genetically-modified mice, including PGRN, IL-10 and TNFR2 deficient mice. Elevated levels of PGRN were found in colitis samples from human IBD patients and mouse colitis models in comparison to the corresponding controls. PGRN-deficient mice became highly susceptible to DSS- and TNBS-induced colitis, whereas recombinant PGRN ameliorated the pathology and reduced the histological score in both DSS and TNBS colitis models. In addition, hematopoietic-derived PGRN was critical for protection against DSS-induced colitis, and lack of PGRN signaling in CD4+ T cells also exacerbated experimental colitis. PGRN-mediated protective effect in colitis was compromised in the absence of IL-10 signaling. In addition, PGRN's effect was also largely lost in the TNFR2-deficient colitis model. Collectively, these findings not only provide the new insight into PGRN's anti-inflammatory action in vivo, but may also present PGRN and its derivatives as novel biological agent for treating IBD.
PMCID: PMC4228332  PMID: 25387791
13.  Crystal structure of betulinic acid methanol monosolvate 
The title compound [systematic name: 3β-hy­droxy­lup-20(29)-en-28-oic acid methanol monosolvate], C30H48O3·CH3OH, is a solvent pseudopolymorph of a naturally occurring plant-derived lupane-type penta­cyclic triterpenoid, which was isolated from the traditional Chinese medicinal plant Syzygium jambos (L.) Alston. The dihedral angle between the planes of the carb­oxy­lic acid group and the olefinic group is 12.17 (18)°. The A/B, B/C, C/D and D/E ring junctions are all trans-fused. In the crystal, O—H⋯O hydrogen bonds involving the hy­droxy and carb­oxy­lic acid groups and the methanol solvent mol­ecule give rise to a two-dimensional network structure lying parallel to (001).
PMCID: PMC4257419  PMID: 25553022
crystal structure; betulinic acid; lup-20(29)-en-28-oic acid; Syzygium jambos (L.) Alston; hydrogen bonding; natural product
14.  Selection on a Variant Associated with Improved Viral Clearance Drives Local, Adaptive Pseudogenization of Interferon Lambda 4 (IFNL4) 
PLoS Genetics  2014;10(10):e1004681.
Interferon lambda 4 gene (IFNL4) encodes IFN-λ4, a new member of the IFN-λ family with antiviral activity. In humans IFNL4 open reading frame is truncated by a polymorphic frame-shift insertion that eliminates IFN-λ4 and turns IFNL4 into a polymorphic pseudogene. Functional IFN-λ4 has antiviral activity but the elimination of IFN-λ4 through pseudogenization is strongly associated with improved clearance of hepatitis C virus (HCV) infection. We show that functional IFN-λ4 is conserved and evolutionarily constrained in mammals and thus functionally relevant. However, the pseudogene has reached moderately high frequency in Africa, America, and Europe, and near fixation in East Asia. In fact, the pseudogenizing variant is among the 0.8% most differentiated SNPs between Africa and East Asia genome-wide. Its raise in frequency is associated with additional evidence of positive selection, which is strongest in East Asia, where this variant falls in the 0.5% tail of SNPs with strongest signatures of recent positive selection genome-wide. Using a new Approximate Bayesian Computation (ABC) approach we infer that the pseudogenizing allele appeared just before the out-of-Africa migration and was immediately targeted by moderate positive selection; selection subsequently strengthened in European and Asian populations resulting in the high frequency observed today. This provides evidence for a changing adaptive process that, by favoring IFN-λ4 inactivation, has shaped present-day phenotypic diversity and susceptibility to disease.
Author Summary
The genetic association with clearance of Hepatitis C virus (HCV) is one of the strongest and most elusive known associations with disease. The genetic variant more strongly associated with improved HCV clearance inactivates the recently discovered IFNL4 gene, which encodes for antiviral IFN-λ4 protein, and turns it into a polymorphic pseudogene. We show that functional IFN-λ4 is conserved and functionally important in mammals. In humans though the inactivating mutation appeared in Africa just before the out-of-Africa migration and quickly became advantageous, with the strength of selection (the degree of advantage) varying across human groups. In particular, selection became stronger out of Africa and was strongest in East Asia, raising the frequency of the pseudogene and resulting in the virtual loss of functional IFN-λ4 protein in several Asian populations. Although the environmental force driving selection is unknown, this process resulted in variable clearance of HCV in modern human populations. The complex selective history of IFNL4-inactivating allele has thus shaped present-day heterogeneity across populations not only in genetic variation, but also in relevant phenotypes and susceptibility to disease.
PMCID: PMC4199494  PMID: 25329461
15.  Role of Nrf2 in chronic liver disease 
World Journal of Gastroenterology : WJG  2014;20(36):13079-13087.
Nuclear erythroid 2-related factor 2 (Nrf2) is a central regulator of antioxidative response elements-mediated gene expression. It has a significant role in adaptive responses to oxidative stress by interacting with the antioxidant response element, which induces the expression of a variety of downstream targets aimed at cytoprotection. Previous studies suggested oxidative stress and associated damage could represent a common link between different forms of diseases. Oxidative stress has been implicated in various liver diseases, including viral hepatitis, nonalcoholic fatty liver disease/steatohepatitis, alcoholic liver disease and drug-induced liver injury. Nrf2 activation is initiated by oxidative or electrophilic stress, and aids in the detoxification and elimination of potentially harmful exogenous chemicals and their metabolites. The expression of Nrf2 has been observed throughout human tissue, with high expression in detoxification organs, especially the liver. Thus, Nrf2 may serve as a major regulator of several cellular defense associated pathways by which hepatic cells combat oxidative stress. We review the relevant literature concerning the crucial role of Nrf2 and its signaling pathways against oxidative stress to protect hepatic cell from oxidative damage during development of common chronic liver diseases. We also review the use of Nrf2 as a therapeutic target to prevent and treat liver diseases.
PMCID: PMC4177487  PMID: 25278702
Nuclear erythroid 2-related factor 2; Chronic liver disease; Oxidative stress; Reactive oxygen species; Hepatic injury; Hepatic protection
16.  Inhibition of KL-6/MUC1 glycosylation limits aggressive progression of pancreatic cancer 
World Journal of Gastroenterology : WJG  2014;20(34):12171-12181.
AIM: To evaluate the significance of KL-6/MUC1 (a type of MUC1) glycosylation in pancreatic cancer progression.
METHODS: KL-6/MUC1 expression was detected by immunohistochemistry in 48 patients with pancreatic duct cell carcinoma. The N-/O-glycosylation inhibitors (tunicamycin and benzyl-N-acetyl-α-galactosaminide) were then used to interfere with KL-6/MUC1 glycosylation in two pancreatic carcinoma cell lines, and the effects on KL-6/MUC1 expression, and cell adhesion and invasion were determined. In addition, protein expression of epithelial-mesenchymal transition markers, E-cadherin and vimentin, were evaluated in cells after treatment with glycosylation inhibitors.
RESULTS: Overexpression of KL-6/MUC1 was found in all pancreatic cancer tissues, but not in the surrounding normal pancreatic tissues. The expression profile of KL-6/MUC1 was significantly decreased after treatment with the inhibitors. The adhesion and invasive ability of cancer cells were significantly decreased after drug treatment, and increased E-cadherin and decreased vimentin expression were found.
CONCLUSION: KL-6/MUC1 glycosylation is involved in pancreatic cancer metastasis and invasion. Therapeutic strategies which target this may help control the aggressive behavior of pancreatic cancer cells.
PMCID: PMC4161802  PMID: 25232251
Benzyl-N-acetyl-α-galactosaminide; Glycosylation; KL-6/MUC1; Pancreatic carcinoma; Tunicamycin
17.  Association of the Three Common SNPs of Cyclooxygenase-2 Gene (rs20417, rs689466, and rs5275) with the Susceptibility of Breast Cancer: An Updated Meta-Analysis Involving 34,590 Subjects 
Disease Markers  2014;2014:484729.
Several single nucleotide polymorphisms have been identified in cyclooxygenase-2 (COX-2) genes (e.g., −765 G>C (rs20417), −1195G>A (rs689466), and 8473 C>T (rs5275)). The association of these SNPs with the risk of different cancer types is still controversial. This study aims to evaluate the correlation between these SNPs and breast cancer risk in different ethnic groups. We have searched PubMed, Web of Knowledge, and Embase for relevant studies. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to estimate the strength of the associations. A total of 13 studies (15,330 cases and 19,260 controls) were eligible for meta-analysis. This meta-analysis showed that COX-2 rs20417 polymorphism was correlated with an increased risk of breast cancer in Caucasians, while rs689466 was associated with a decreased risk of breast cancer in Caucasians. The rs5275 polymorphism had no association with breast cancer risk.
PMCID: PMC4151597  PMID: 25214704
18.  Imidazole-derived 2-[N-carbamoylmethyl-alkylamino]acetic acids, substrate-dependent modulators of insulin-degrading enzyme in amyloid-β hydrolysis 
Substrates of Insulin-Degrading Enzyme are numerous and share little homology, like amyloid-beta and insulin. Small molecules binding both at the permanent exosite and at the discontinuous, conformational catalytic site, were discovered and co-crystallized with Insulin-Degrading Enzyme. Selective inhibition of amyloid-beta degradation over insulin hydrolysis was possible. Neuroblastoma cells treated with the optimized compound display a dose-dependent increase in amyloid-beta levels.
PMCID: PMC4128174  PMID: 24735644
enzymes; medicinal chemistry; Structure-activity relationships; amyloid-beta peptides; inhibitors; X-ray diffraction
19.  Discovering novel anti-HCV compounds with inhibitory activities toward HCV NS3/4A protease 
Acta Pharmacologica Sinica  2014;35(8):1074-1081.
To discover novel hepatitis C virus (HCV) inhibitors and elucidate the mechanism of action of the active compounds.
HCV subgenomic replicon-based luciferase reporter cell line was used to screen 1200 synthetic compounds with novel structures. Huh7.5.1 cell line stably transfected with HCV NS3/4A protease reporter was established to investigate the anti-HCV mechanism of the active compounds. The active compounds were further examined in an in vitro HCV infection assay to confirm their anti-HCV activity.
After two-round screening in the anti-HCV replicon assay, some 2,4-diaminoquinazoline derivatives and carboxamide analogues were found to possess anti-HCV replicon activities (the IC50 values were less than 5 μmol/L). Among them, two representative compounds HZ-1157 and LZ-110618-6 inhibited HCV NS3/4A protease with IC50 values of 1.0 and 0.68 μmol/L, respectively. Furthermore, HZ-1157 and LZ-110618-6 inhibited HCV infection in vitro with IC50 values of 0.82 and 0.11 μmol/L, respectively.
Some 2,4-diaminoquinazoline derivatives and carboxamide analogues have been identified as novel anti-HCV compounds.
PMCID: PMC4125721  PMID: 25066323
hepatitis C virus; NS3/4A protease; secreted embryonic alkaline phosphatase (Seap); 2,4-diaminoquinazoline; carboxamide; telaprevir
20.  Modulation of the CXC Chemokine Receptor 4 Agonist Activity of Ubiquitin through C-Terminal Protein Modification 
Biochemistry  2013;52(24):4184-4192.
Extracellular ubiquitin has recently been described as a CXC chemokine receptor (CXCR) 4 agonist. Studies on the structure–function relationship suggested that the C-terminus of ubiquitin facilitates CXCR4 activation. It remains unknown, however, whether C-terminal processing of ubiquitin could be biologically relevant and whether modifications of the ubiquitin C-terminus can modulate CXCR4 activation. We show that C-terminal truncated ubiquitin antagonizes ubiquitin and stromal cell-derived factor (SDF)-1α induced effects on cell signaling and function. Reduction of cell surface expression of insulin degrading enzyme (IDE), which cleaves the C-terminal di-Gly of ubiquitin, enhances ubiquitin induced reduction of cAMP levels in BV2 and THP-1 cells, but does not influence changes in cAMP levels in response to SDF-1α. Reduction of cell surface IDE expression in THP-1 cells also increases the chemotactic activity of ubiquitin. As compared with native ubiquitin, C-terminal Tyr extension of ubiquitin results in reduced CXCR4 mediated effects on cellular cAMP levels and abolishes chemotactic activity. Replacement of C-terminal di-Gly of ubiquitin with di-Val or di-Arg enhances CXCR4 mediated effects on cAMP levels and the di-Arg substitution exerts increased chemotactic activity, when compared with wild type ubiquitin. The chemotactic activities of the di-Val and di-Arg mutants and their effects on cAMP levels can be antagonized with C-terminal truncated ubiquitin. These data suggest that the development of CXCR4 ligands with enhanced agonist activities is possible and that C-terminal processing of ubiquitin could constitute a biological mechanism, which regulates termination of receptor signaling.
PMCID: PMC4113718  PMID: 23697661
21.  Pathophysiology of anthrax 
Infection by Bacillus anthracis in animals and humans results from accidental or intentional exposure, by oral, cutaneous or pulmonary routes, to spores, which are normally present in the soil. Treatment includes administration of antibiotics, vaccination or treatment with antibody to the toxin. A better understanding of the molecular basis of the processes involved in the pathogenesis of anthrax namely, spore germination in macrophages and biological effects of the secreted toxins on heart and blood vessels will lead to improved management of infected animals and patients. Controlling germination will be feasible by inhibiting macrophage paralysis and cell death. On the other hand, the control of terminal hypotension might be achieved by inhibition of cardiomyocyte mitogen-activated protein kinase and stimulation of vessel cAMP.
PMCID: PMC4109055  PMID: 19273366
Anthrax; Heart Failure; Rats; Review
22.  Magnetic Resonance Imaging for the Normal Mesostenium and Involvement of the Mesostenium in Acute Pancreatitis 
BioMed Research International  2014;2014:924845.
The main point of this paper is to study MRI findings of the normal mesostenium and the involvement of the mesostenium in acute pancreatitis and to discuss the relationship between the involvement of the mesostenium and the severity of acute pancreatitis. In clinical practice, the mesenterical involvement in acute pancreatitis was often observed on MRI in daily works, which was little recorded in the reported studies. We conducted the current study to assess the mesenterical involvement in acute pancreatitis with MRI. We found that the mesenterical involvement of acute pancreatitis patients is common on MRI. The mesenterical involvement has a positive correlation with the MR severity index and the Acute Physiology and Chronic Healthy Evaluation II scoring system. It has been shown that MR can be used to visualize mesenterical involvement, which is a supplementary indicator in evaluating the severity of acute pancreatitis and local and systemic complications.
PMCID: PMC4127251  PMID: 25136639
23.  RGD Modified Apoferritin Nanoparticles for Efficient Drug Delivery to Tumors 
ACS nano  2013;7(6):4830-4837.
Ferritin is a major iron storage protein found in humans and most living organisms. Each ferritin is comprised of 24 subunits, which self-assemble to form a cage-like nanostructure. FRT nanocages can be genetically modified to present a peptide sequence on the surface. Recently, we demonstrated that Cys-Asp-Cys-Arg-Gly-Asp-Cys-Phe-Cys (RGD4C)-modified ferritin can efficiently home to tumors through RGD integrin αvβ3 interaction. Though promising, studies on evaluating surface modified ferritin nanocages as drug delivery vehicles have seldom been reported. Herein we showed that after being pre-complexed with Cu(II), doxorubicin can be loaded onto RGD modified apoferritin nanocages with high efficiency (up to 73.49wt%). When studied on U87MG subcutaneous tumor models, these doxorubicin-loaded ferritin nanocages showed a longer circulation half-life, higher tumor uptake, better tumor growth inhibition, and less cardiotoxicity than free doxorubicin. Such a technology might be extended to load a broad range of therapeutics and holds great potential in clinical translation.
PMCID: PMC3705644  PMID: 23718215
ferritin; drug delivery; integrin αvβ3; nanocarrier; doxorubicin
24.  EVB Simulations of the Chemical Mechanism of ATP to cAMP Conversion by Anthrax Edema Factor$ 
Biochemistry  2013;52(15):2672-2682.
The two-metal catalysis by the adenylyl cyclase domain of the anthrax edema factor toxin was simulated using the empirical valence bond (EVB) quantum mechanical/molecular mechanical approach. These calculations considered the energetics of the nucleophile deprotonation and a new PO bond formation in the aqueous solution and in the enzyme-substrate complex present in the crystal structure models of the reactant and product state of the reaction. Our calculations support reaction pathway that involves metal-assisted proton transfer from the nucleophile to bulk aqueous solution followed by subsequent formation of an unstable pentavalent intermediate that decomposes into cAMP and pyrophosphate (PPi). This pathway involves ligand exchange in the first solvation sphere of the catalytic metal. The last step of the reaction – the cleavage of the PO bond to PPi – has the highest activation barrier of 13.9 kcal/mol but this barrier height is too close to 12.5 kcal/mol calculated for the nucleophilic attack step to make a definitive conclusion about the rate-limiting step. The calculated reaction mechanism is supported by reasonable agreement between the experimental and calculated catalytic rate constant decrease due to the mutation of the active site lysine 346 to arginine.
PMCID: PMC4069339  PMID: 23480863
25.  The transcription factor Pou3f1 promotes neural fate commitment via activation of neural lineage genes and inhibition of external signaling pathways 
eLife  2014;3:e02224.
The neural fate commitment of pluripotent stem cells requires the repression of extrinsic inhibitory signals and the activation of intrinsic positive transcription factors. However, how these two events are integrated to ensure appropriate neural conversion remains unclear. In this study, we showed that Pou3f1 is essential for the neural differentiation of mouse embryonic stem cells (ESCs), specifically during the transition from epiblast stem cells (EpiSCs) to neural progenitor cells (NPCs). Chimeric analysis showed that Pou3f1 knockdown leads to a markedly decreased incorporation of ESCs in the neuroectoderm. By contrast, Pou3f1-overexpressing ESC derivatives preferentially contribute to the neuroectoderm. Genome-wide ChIP-seq and RNA-seq analyses indicated that Pou3f1 is an upstream activator of neural lineage genes, and also is a repressor of BMP and Wnt signaling. Our results established that Pou3f1 promotes the neural fate commitment of pluripotent stem cells through a dual role, activating internal neural induction programs and antagonizing extrinsic neural inhibitory signals.
eLife digest
After an egg has been fertilized, it undergoes a series of divisions to produce a ball of cells known as a blastocyst. The cells within the blastocyst are pluripotent stem cells, which have the potential to become many different types of cell. After a few days, the stem cells organize into three layers—an innermost layer called the endoderm, a middle layer of mesoderm, and an outer layer of ectoderm—that ultimately give rise to different types of tissues.
The brain and nervous system are formed from cells in the neuroectoderm, which is part of the ectoderm. Now, Zhu et al. have shown that a transcription factor called Pou3f1 triggers stem cells within a region of the ectoderm to turn into neural progenitor cells, thereby generating the neuroectoderm. These neural progenitor cells then go on to become neurons and glial cells that make up the brain and nervous system.
Using a virus to reduce levels of Pou3f1 in embryonic stem cells grown in a dish led to a drop in the number of stem cells that committed to neural progenitor cells. Overexpressing Pou3f1 in the stem cells restored the number of neural progenitor cells. Together these results showed that Pou3f1 is both necessary and sufficient for the conversion of embryonic stem cells into future neurons and glia.
The same result was seen when embryonic stem cells containing either reduced or elevated levels of Pou3f1 were injected into 2.5-day-old mouse blastocysts, which were then implanted into surrogate females. The resulting embryos comprised some cells with normal levels of Pou3f1, and others with either too little or too much. Cells with elevated Pou3f1 mostly became neural progenitors, whereas those with reduced levels rarely did so. Gene expression studies revealed that Pou3f1 promoted the formation of neural progenitor cells by activating the expression of pro-neuronal genes inside the stem cells, and by blocking anti-neuronal pathways called Wnt/BMP signaling cascades initiated outside the cells.
By revealing the two roles of Pou3f1, Zhu et al. have increased our understanding of one of the earliest stages of nervous system development. Further work is required to determine exactly how Pou3f1 exerts its effects and, in particular, whether it performs its two roles simultaneously or in sequence.
PMCID: PMC4095939  PMID: 24929964
Pou3f1; neural fate commitment; pluripotent stem cell; intrinsic factor; extrinsic signal; BMP/Wnt pathways; chicken; mouse

Results 1-25 (190)