Encapsulating quantum dots into enveloped virus in living cells for tracking virus infection

Utilization of quantum dots (QDs) for single virus tracking has attracted growing interest. Through modification of viral surface proteins, viruses can be labeled with various functionalized QDs and used for tracking the routes of viral infections. However, incorporation of QDs on the viral surface may affect the efficiency of viral entry and alter virus-cell interactions. Here, we describe that QDs can be encapsulated into the capsid of vesicular stomatitis virus glycoprotein (VSV-G) pseudotyped lentivirus (PTLV) in living cells without modification of the viral surface. QDs conjugated with modified genomic RNAs (gRNAs), which contain a packaging signal (Psi) sequence for viral genome encapsulation, can be packaged into virions together with the gRNAs. QD-containing PTLV demonstrated similar entry efficiency as the wild-type PTLV. After infection, QD signals entered the Rab5+ endosome and then moved to the microtubule organizing center of the infected cells in a microtubule-dependent manner. Findings in this study are consistent with previously reported infection routes of VSV and VSV-G pseudotyped lentivirus, indicating that our established QD packaging approach can be used for enveloped virus labeling and tracking.

KH902 suppresses high glucose-induced migration and sprouting of human retinal endothelial cells by blocking VEGF and PIGF

AIMS

Vascular endothelial growth factor (VEGF) and placental growth factor (PlGF) are upregulated in many ocular neovascular diseases such as diabetic retinopathy (DR). KH902 is a recombinant fusion protein with its binding ligand taken from the domains of VEGF receptor-1 (VEGFR-1) and VEGF receptor-2 (VEGFR-2) and can bind all VEGF-A isoforms and PlGF. The aim of this study was to investigate the underlying mechanisms of anti-angiogenic effects of KH902.

METHODS

The toxic effect of KH902 on cultured human retinal endothelial cells (HRECs) was measured by Annexin V/PI staining and MTT assay. The concentrations of secreted VEGF and PlGF were measured by ELISA. The migration of HRECs was assessed by scratch wound and transwell assay. The sprouting of HRECs was determined by tube formation assay. The protein levels of Src, p-Src, PI3K, Akt1, p-Akt1, Erk1/2 and p-Erk1/2 were measured by Western blot.

RESULTS

KH902 at the concentrations from 100 ng/ml to 100 µg/ml had no cytotoxicity to cultured HRECs. KH902 bound not only VEGF165, but also PlGF that were secreted by HRECs under high glucose condition. A 500 ng/ml of KH902 significantly suppressed high glucose-induced migration and sprouting of HRECs through downregulating the expression of PI3K and inhibiting the activation of Src, Akt1 and Erk1/2.

CONCLUSION

Our study indicates that KH902 suppresses high glucose-induced migration and sprouting of HRECs through not only binding VEGF, but also PlGF to inhibit the activation of Src-Akt1-Erk1/2 pathway. KH902 is a drug that potentially inhibits angiogenic pathways involving in DR or other ocular neovascular diseases.

Identification and characterization of complex dual nuclear localization signals in human bocavirus NP1: identification and characterization of complex dual nuclear localization signals in human bocavirus NP1

Human bocavirus (HBoV), closely related to canine minute virus (MVC) and bovine parvovirus (BPV), is a new member of the Bocavirus genus within the Parvoviridae family. The non-structural protein NP1 of HBoV is a nuclear localized protein and plays an important role in DNA replication as well as in the evasion of host innate immunity. In the current study, we provide the first evidence that NP1 possesses a non-classical nuclear localization signal (ncNLS) (amino acids 7-50). Embedded within this ncNLS is a classical bipartite nuclear localization signal (cNLS) (amino acids 14-28), capable of transporting a heterologous cytoplasmic protein β-galactosidase fusion protein (β-gal-EGFP) to the nucleus via the classical importin α/β1-mediated pathway. Amino acids 7-50 containing the cNLS and the ncNLS of NP1 or full-length NP1 interact with importin α1, importin β1 and importin β1Δ, which lacks the importin α binding domain, indicating that the nuclear import of NP1 is through both conventional importin α/β1 heterodimer- and non-classical importinß1-mediated pathways. Given that the arrangement of a cNLS embedded within an ncNLS is unusual in viral proteins, our data together reveal a novel molecular mechanism underlying the nuclear import of HBoV NP1, providing a basis for further understanding its biological function.

Electrical tomography using atomic force microscopy and its application towards carbon nanotube-based interconnects

The fabrication and integration of low-resistance carbon nanotubes (CNTs) for interconnects in future integrated circuits requires characterization techniques providing structural and electrical information at the nanometer scale. In this paper we present a slice-and-view approach based on electrical atomic force microscopy. Material removal achieved by successive scanning using doped ultra-sharp full-diamond probes, manufactured in-house, enables us to acquire two-dimensional (2D) resistance maps originating from different depths (equivalently different CNT lengths) on CNT-based interconnects. Stacking and interpolating these 2D resistance maps results in a three-dimensional (3D) representation (tomogram). This allows insight from a structural (e.g. size, density, distribution, straightness) and electrical point of view simultaneously. By extracting the resistance evolution over the length of an individual CNT we derive quantitative information about the resistivity and the contact resistance between the CNT and bottom electrode.

Human bocavirus NP1 inhibits IFN-β production by blocking association of IFN regulatory factor 3 with IFNB promoter

Human bocavirus (HBoV) mainly infects young children. Although many infected children suffer from respiratory or gastroenteric tract diseases, an association between HBoV and these diseases is not definite. Because modulation of type I IFN is crucial for viruses to establish efficient replication, in this study, we tested whether HBoV modulates type I IFN production. We observed that a nearly full-length HBoV clone significantly reduced both Sendai virus (SeV)- and poly(deoxyadenylic-thymidylic) acid-induced IFN-β production. Further study showed that NP1 blocked IFN-β activation in response to SeV, poly(deoxyadenylic-thymidylic) acid, and IFN-β pathway inducers, including retinoic acid-inducible protein I, mitochondrial antiviral signaling protein, inhibitor of κB kinase ε, and TANK-binding kinase 1. In addition, NP1 interfered with IRF-3-responsive PRD(III-I) promoter activated by SeV and a constitutively active mutant of IRF-3 (IRF-3/5D). Although NP1 suppressed the IRF-3 pathway, it did not affect IRF-3 activation processes, including phosphorylation, dimerization, and nuclear translocation. Coimmunoprecipitation assays confirmed the interaction between NP1 and IRF-3. Additional deletion mutagenesis and coimmunoprecipitation assays revealed that NP1 bound to the DNA-binding domain of IRF-3, resulting in the interruption of an association between IRF-3 and IFNB promoter. Altogether, our results indicate that HBoV NP1 blocks IFN production through a unique mechanism. To our knowledge, this is the first study to investigate the modulation of innate immunity by HBoV. Our findings suggest a potential immune-evasion mechanism used by HBoV and provide a basis for better understanding HBoV pathogenesis.

Optimized self-microemulsifying drug delivery systems (SMEDDS) for enhanced oral bioavailability of astilbin

The main purpose of this research work was to design an optimized self micro-emulsifying drug delivery system (SMEDDS) to enhance the bioavailability of the poor water soluble drug, astilbin. The solubility of astilbin was evaluated in various vehicles. Pseudoternary phase diagrams were used to select the components and their ranges by evaluating the micro-emulsification area. Central composite design was applied to optimize the properties of the formulation, including particle size, polydispersity index, drug loading capacity and effective intestinal permeability. The optimized SMEDDS characteristics were investigated including the study of factors influencing particle size and showed the stability of microemulsion when varying the pH and volume of diluents. In vitro drug release profile study was performed using the reverse dialysis method where 95% of the drug was released after 4 h. The developed astilbin SMEDDS was subjected to bioavailability studies in beagle dogs by LC-MS and showed a significant enhancement of bioavailability, indicating the possibility of using SMEDDS as possible drug carrier for astilbin.

Examining the overlap between genome-wide rare variant association signals and linkage peaks in rheumatoid arthritis

OBJECTIVE

With the exception of the major histocompatibility complex (MHC) and STAT4, no other rheumatoid arthritis (RA) linkage peak has been successfully fine-mapped to date. This apparent failure to identify association under peaks of linkage could be ascribed to the examination of common variation, when linkage is likely to be driven by rare variants. The purpose of this study was to investigate the overlap between genome-wide rare variant RA association signals observed in the Wellcome Trust Case Control Consortium (WTCCC) study and 11 replicating RA linkage peaks, defined as regions with evidence for linkage in >1 study.

METHODS

The WTCCC data set contained 40,482 variants with minor allele frequency of ≤0.05 in 1,860 RA patients and 2,938 controls. Genotypes of all rare variants within a given gene region were collapsed into a single locus and a global P value was calculated per gene.

RESULTS

The distribution of rare variant signals (association P≤10(-5)) was found to differ significantly between regions with and without linkage evidence (P=2×10(-17) by Fisher's exact test). No significant difference was observed after data from the MHC region were removed or when the effect of the HLA-DRB1 locus was accounted for.

CONCLUSION

The results suggest that rare variant association signals are significantly overrepresented under linkage peaks in RA, but the effect is driven by the MHC. This is the first study to examine the overlap between linkage peaks and rare variant association signals genome-wide in a complex disease.

Melittin liposomes surface modified with poloxamer 188: in vitro characterization and in vivo evaluation

Melittin liposomes surface modified with poloxamer 188 were developed, and the effect of poloxamer 188 was investigated with regard to anti-cancer effect and vascular stimulation. Melittin liposomes surface modified with poloxamer 188 at different concentrations (0%, 2%, and 5%) were prepared using the adsorption method, followed by in vitro characterization, including entrapment efficiency, zeta potential, particle size, and morphology. Subsequently, the influence of repeated freeze-thawing on the liposomes was investigated, and the effect of poloxamer 188 on the repeated freeze-thawing process was explored. Vascular stimulation effects of MLT, and MLT liposome that surface coated with or without poloxamer were all studied. Pharmacokinetics of the different MLT preparations were determined and the anticancer activity of the MLT formulations was investigated. The particle size of the liposomes gradually increased with increasing poloxamer 188 content, while the entrapment efficiency did not change significantly. After the first freeze-thaw cycle, size and PDI were both markedly reduced, entrapment efficiency rose, and there was no significant change of zeta potential. The vascular irritation caused by MLT could be reduced to an extent by encapsulation in liposome, but not completely eliminated, while liposomes coated with poloxamer 188 can effectively abolish the phenomenon. Melittin liposomes with surface modified by poloxamer exhibit enhanced bioavailability, effective anticancer activity, and reduced side effects compared with melittin solution. Poloxamer plays an important role in melittin liposomes.

In vitro and in vivo evaluation of sanguinarine liposomes prepared by a remote loading method with three different ammonium salts

Sanguinarine liposomes were prepared by a remote loading method using three different ammonium salts. A series of studies, including in vitro release, in vitro and in vivo anti-tumor effects and pharmacokinetics in rats, were conducted. The three liposomes showed pH-sensitive release characteristics in vitro, but there were obvious variations in their release profiles. Among the three liposomes, the liposomes made using ammonium citrate and phosphate possessed better anti-tumor activity in vitro and in vivo, compared with the liposome using ammonium sulfate. Pharmacokinetics test results in rats indicated that sanguinarine liposomes have notably elevated AUC (P<0.05) and markedly lower CL (P<0.05) compared with the solution, but there were no obvious differences between the three liposomes. The present study may be useful for better understanding and better choice of a suitable ammonium salt for the remote loading method.

HLA-DPB1-COL11A2 and three additional xMHC loci are independently associated with RA in a UK cohort

The aim of this study was to investigate the complex association pattern of the extended major histocompatibility complex (xMHC) region with rheumatoid arthritis (RA) susceptibility to identify effects independent of HLA-DRB1. A total of 1804 RA cases and 1474 controls were included. High-resolution HLA-DRB1 typing was performed. Subjects were genotyped for 1546 single-nucleotide polymorphisms (SNPs) using Affymetrix GeneChip 500 K (Santa Clara, CA, USA) as part of the Wellcome Trust Case Control Consortium Study. Statistical analysis was carried out using PLINK. To avoid confounding by RA-associated HLA-DRB1 alleles, we analyzed xMHC SNPs using a data set with pairwise matching of cases and controls on DRB1 genotypes. A total of 594 case-control pairs with identical DRB1 genotypes were identified. After this adjustment, 104 SNPs remained significantly associated with RA (P<0.05), suggesting that additional RA loci independent of HLA-DRB1 can be found in the xMHC region. Of these, four loci showed the strongest associations with RA (P<0.005): ZNF391, the olfactory receptor (OR) gene cluster, C6orf26-RDBP and HLA-DPB1-COL11A2. An additional locus mapping to the BTN (butyrophilin) cluster showed independent association with RA in anti-cyclic citrullinated peptide-positive patients exclusively. We have validated the previously described independent association of the HLA-DPB1-COL11A2 locus with RA. In addition, association with three novel independent RA loci in the xMHC region (ZNF391, OR2H1 and C6orf26-RDBP) has been detected.

Association of the AFF3 gene and IL2/IL21 gene region with juvenile idiopathic arthritis

Recent genetic studies have led to identification of numerous loci that are associated with susceptibility to autoimmune diseases. The strategy of using information from these studies has facilitated the identification of novel juvenile idiopathic arthritis (JIA) susceptibility loci, specifically, PTPN22 and IL2RA. Several novel autoimmune susceptibility loci have recently been identified, and we hypothesise that single-nucleotide polymorphisms (SNPs) within these genes may also be JIA susceptibility loci. Five SNPs within the genes AFF3, IL2/IL21, IL7R, CTLA4 and CD226, previously associated with multiple autoimmune diseases were genotyped, in a large data set of Caucasian JIA patients and controls, and tested for association with JIA. We identified two susceptibility loci for JIA, AFF3 and the IL2/IL21 region and additional weak evidence supporting an association with the CTLA4 and IL7R genes, which warrant further investigation. All results require validation in independent JIA data sets. Further characterisation of the specific causal variants will be required before functional studies can be performed.