Altering an artificial Gagpolnef polyprotein and mode of ENV co-administration affects the immunogenicity of a clade C HIV DNA vaccine

HIV-1 candidate vaccines expressing an artificial polyprotein comprising Gag, Pol and Nef (GPN) and a secreted envelope protein (Env) were shown in recent Phase I/II clinical trials to induce high levels of polyfunctional T cell responses; however, Env-specific responses clearly exceeded those against Gag. Here, we assess the impact of the GPN immunogen design and variations in the formulation and vaccination regimen of a combined GPN/Env DNA vaccine on the T cell responses against the various HIV proteins. Subtle modifications were introduced into the GPN gene to increase Gag expression, modify the expression ratio of Gag to PolNef and support budding of virus-like particles. I.m. administration of the various DNA constructs into BALB/c mice resulted in an up to 10-fold increase in Gag- and Pol-specific IFNγ(+) CD8(+) T cells compared to GPN. Co-administering Env with Gag or GPN derivatives largely abrogated Gag-specific responses. Alterations in the molar ratio of the DNA vaccines and spatially or temporally separated administration induced more balanced T cell responses. Whereas forced co-expression of Gag and Env from one plasmid induced predominantly Env-specific T cells responses, deletion of the only H-2(d) T cell epitope in Env allowed increased levels of Gag-specific T cells, suggesting competition at an epitope level. Our data demonstrate that the biochemical properties of an artificial polyprotein clearly influence the levels of antigen-specific T cells, and variations in formulation and schedule can overcome competition for the induction of these responses. These results are guiding the design of ongoing pre-clinical and clinical trials.     

Standardised measures of needs,stigma and informal care in schizophrenia using a bottom-up,cross-cultural approach

Background There is a lack of instruments to measure the needs, stigma and informal care of people with schizophrenia that take account of sociocultural variation and patients'' and formal and informal carers'' opinions and experiences.Aims To develop questionnaires to measure stigma, needs and informal (non-professional) care for people with schizophrenia.Method We undertook the study in seven countries and in English, Spanish and Portuguese. We first held focus group discussions with patients, formal carers (professionals) and informal carers (family and friends) in Spain, the UK, Argentina, Brazil, Chile and Venezuela to elicit the main dimensions of needs, stigma and informal care. We then held nominal group discussions about these dimensions with patients, family members and professionals in Spain, Portugal and the UK, to develop the instruments.Results Three hundred and three people participated in 46 focus groups and results were discussed in three nominal groups, each involving eight participants. Three instruments were developed in this iterative process: needs for care (46 items), stigma (38 items) and informal care (20 items).Conclusions These instruments are based on service users'' and carers'' views and experiences and have cross-cultural validity. They will have application in assessment of outcomes for people with schizophrenia and their families.     

Measurement of oxidatively generated base damage to nucleic acids in cells: facts and artifacts

The search for DNA biomarkers of oxidative stress has been hampered for several decades by the lack of relevant information on base oxidation products and the challenging issue of measuring low amounts of lesions, typically a few modifications within the range 10⁶?C10⁸ normal bases. In addition and this was ignored for a long time, there is a risk of artifactual oxidation of overwhelming nucleobases during DNA extraction and subsequent workup that has led to overestimation of some base damage up to 2?C3 orders of magnitude. The main aim of the survey is to critically review the available methods that have been developed for measuring oxidatively generated base damage in nuclear and mitochondrial DNA. Among the chromatographic methods, high-performance liquid chromatography associated with tandem mass spectrometry (HPLC?CMS/MS) is the most accurate and versatile approach whereas HPLC?Celectrochemical detection (ECD) is restricted to electrochemically active modifications. These methods allow measuring several single oxidized pyrimidine and purine bases, tandem base lesions and interstrand DNA cross-links in nuclear DNA. As complementary analytical tools, enzymatic methods that associate DNA repair enzymes with either the alkaline comet assay or the alkaline elution technique are suitable for assessing low variations in the level of different classes of oxidatively generated DNA lesions. Most of the immunoassays suffer from a lack of specificity due to the occurrence of cross-reactivity with overwhelming normal bases. One major exception concerns the immunodetection of 5-hydroxymethylcytosine, produced in a relatively high yield as an epigenetic DNA modification. HPLC?CMS/MS is now recognized as the gold standard for measuring oxidized bases and nucleosides in human fluids such as urine, saliva, and plasma.     

Peroxiredoxin 6 promotes upregulation of the prion protein (PrP) in neuronal cells of prion-infected mice

Background

It has been widely established that the conversion of the cellular prion protein (PrP^C) into its abnormal isoform (PrP^Sc) is responsible for the development of transmissible spongiform encephalopathies (TSEs). However, the knowledge of the detailed molecular mechanisms and direct functional consequences within the cell is rare. In this study, we aimed at the identification of deregulated proteins which might be involved in prion pathogenesis.

Findings

Apolipoprotein E and peroxiredoxin 6 (PRDX6) were identified as upregulated proteins in brains of scrapie-infected mice and cultured neuronal cell lines. Downregulation of PrP gene expression using specific siRNA did not result in a decrease of PRDX6 amounts. Interestingly, selective siRNA targeting PRDX6 or overexpression of PRDX6 controlled PrP^C and PrP^Sc protein amounts in neuronal cells.

Conclusions

Besides its possible function as a novel marker protein in the diagnosis of TSEs, PDRX6 represents an attractive target molecule in putative pharmacological intervention strategies in the future.     

Bias in effect size of systemic lupus erythematosus susceptibility loci across Europe: a case-control study

Introduction

Prevalence of an abnormal Papanicolaou smear was significantly increased in lupus patients in cross-sectional studies, associated with a higher prevalence of high-risk human papillomavirus (HPV) infection. The nucleic acid-specific Toll-like receptors (TLRs) locate at the endolysosomal compartments and trigger the induction of cytokines for the innate immune response. This study evaluated whether abnormal host innate immune response in lupus patients may enhance HPV persistence.

Methods

Protein levels of TLRs 3, 7, 8 and 9 in cervical epithelial cells of lupus patients and controls with or without HPV infection were assessed using flow cytometry. Characteristics associated with the differential expression of TLRs in systemic lupus erythematosus (SLE) were elucidated. The effect and interferon-stimulated genes (ISGs) (ISG15 and Mx-1) gene expressions were then measured in oncogenic HeLa (HPV18), CaSki (HPV) and C33A (HPV negative) cell lines using flow cytometry and quantitative real-time PCR. Ex vivo productions of cytokines and interferon-gamma (IFN-??) upon TLR ligands stimulations were subsequently measured using cytometric bead array and ELISA.

Results

For subjects with HPV infection, levels of TLR3 and TLR7 were significantly lower in lupus patients compared with controls. Significantly decreased TLRs 7, 8 and 9 levels were observed in HPV-negative SLE compared to healthy controls. For SLE with and without HPV infection, TLR7 and 9 levels were significantly lower in infected SLE than those in HPV-negative patients. Independent explanatory variables associated with down-regulation of TLR7 level included HPV infection and a higher cumulative dose of prednisolone; while a higher cumulative dose of hydroxychloroquine and HPV infection were associated with down-regulation of TLR9 level. In cervical cell lines, TLRs 3, 7, 8, 9 protein levels and antiviral ISG15 and Mx-1 gene expressions were inhibited in two oncogenic HPV types. Functional data showed that the induction of pro-inflammatory cytokines by TLR ligands (R837, ssRNA and ODN2395) was greatly impaired in CaSki and HeLa than C33A cells.

Conclusions

In conclusion, prednisolone and TLR antagonist (hydroxychloroquine) may down-regulate protein levels of TLR7 and TLR9 in lupus patients, thereby decreasing the innate immune response against HPV infection. Upon infection, HPV further down-regulate TLR7 and 9 levels for viral persistence. Furthermore, reduction of nucleic acid-sensing TLRs 7, 8 and 9 in carcinogenic HPVs ensures that the expression of inducible pro-inflammatory cytokines is minimized to prevent the expression of antiviral ISGs (ISG15 and Mx-1) on a biologically relevant antiviral response.     

Bias in effect size of systemic lupus erythematosus susceptibility loci across Europe: a case-control study

Introduction

We aimed to investigate whether the effect size of the systemic lupus erythematosus (SLE) risk alleles varies across European subpopulations.

Methods

European SLE patients (n = 1,742) and ethnically matched healthy controls (n = 2,101) were recruited at 17 centres from 10 different countries. Only individuals with self-reported ancestry from the country of origin were included. In addition, participants were genotyped for top ancestry informative markers and for 25 SLE associated SNPs. The results were used to compare effect sizes between the Central Eureopan and Southern European subgroups.

Results

Twenty of the 25 SNPs showed independent association with SLE, These SNPs showed a significant bias to larger effect sizes in the Southern subgroup, with 15/20 showing this trend (P = 0.019) and a larger mean odds ratio of the 20 SNPs (1.46 vs. 1.34, P = 0.02) as well as a larger difference in the number of risk alleles (2.06 vs. 1.63, P = 0.027) between SLE patients and controls than for Central Europeans. This bias was reflected in a very significant difference in the cumulative genetic risk score (4.31 vs. 3.48, P = 1.8 × 10^-32). Effect size bias was accompanied by a lower number of SLE risk alleles in the Southern subjects, both patients and controls, the difference being more marked between the controls (P = 1.1 × 10^-8) than between the Southern and Central European patients (P = 0.016). Seven of these SNPs showed significant allele frequency clines.

Conclusion

Our findings showed a bias to larger effect sizes of SLE loci in the Southern Europeans relative to the Central Europeans together with clines of SLE risk allele frequencies. These results indicate the need to study risk allele clines and the implications of the polygenic model of inheritance in SLE.     

Improved cellular specificity of plasmonic nanobubbles versus nanoparticles in heterogeneous cell systems

The limited specificity of nanoparticle (NP) uptake by target cells associated with a disease is one of the principal challenges of nanomedicine. Using the threshold mechanism of plasmonic nanobubble (PNB) generation and enhanced accumulation and clustering of gold nanoparticles in target cells, we increased the specificity of PNB generation and detection in target versus non-target cells by more than one order of magnitude compared to the specificity of NP uptake by the same cells. This improved cellular specificity of PNBs was demonstrated in six different cell models representing diverse molecular targets such as epidermal growth factor receptor, CD3 receptor, prostate specific membrane antigen and mucin molecule MUC1. Thus PNBs may be a universal method and nano-agent that overcome the problem of non-specific uptake of NPs by non-target cells and improve the specificity of NP-based diagnostics, therapeutics and theranostics at the cell level.