Lipidation of a bioactive cyclotide-based CXCR4 antagonist greatly improves its pharmacokinetic profile in vivo

The CXCR4 chemokine is a key molecular regulator of many biological functions controlling leukocyte functions during inflammation and immunity, and during embryonic development. Overexpression of CXCR4 is also associated with many types of cancer where its activation promotes angiogenesis, tumor growth/survival, and metastasis. In addition, CXCR4 is involved in HIV replication, working as a co-receptor for viral entry, making CXCR4 a very attractive target for developing novel therapeutic agents. Here we report the pharmacokinetic profile in rats of a potent CXCR4 antagonist cyclotide, MCo-CVX-5c, previously developed in our group that displayed a remarkable in vivo resistance to biological degradation in serum. This bioactive cyclotide, however, was rapidly eliminated through renal clearance. Several lipidated versions of cyclotide MCo-CVX-5c showed a significant increase in the half-life when compared to the unlipidated form. The palmitoylated version of cyclotide MCo-CVX-5c displayed similar CXCR4 antagonistic activity as the unlipidated cyclotide, while the cyclotide modified with octadecanedioic (18-oxo-octadecanoic) acid exhibited a remarkable decrease in its ability to antagonize CXCR4. Similar results were also obtained when tested for its ability to inhibit growth in two cancer cell lines and HIV infection in cells. These results show that the half-life of cyclotides can be improved by lipidation although it can also affect their biological activity depending on the lipid employed.

Antibacterial efficacy of Lawsonia inermis (Henna) against the predominant endodontic pathogen (Enterococcus faecalis)-An in vitro antimicrobial assay

Introduction and Aim: The prospect of a successful root canal therapy relies on three main factors which includes proper instrumentation, disinfection and obturation of root canal. The goal of the present study is to analyse the anti-microbial efficacy of henna (Lawsonia inermis) against the major endodontic pathogen, Enterococcus faecalis.   Materials and Methods: In this study, the antibacterial efficacy of Lawsonia inermis is investigated against Enterococcs feacalis using the method of agar disc diffusion. Extracts of L. inermis were prepared by using methanol as an extraction solvent, whereas DMSO (Dimethyl sulfoxide) and water were used as dissolution solvents. The diluted henna sample was used as the test sample, while positive control used was chlorhexidine gluconate solution and the negative control used was saline. The bacteria were cultured, and the samples were placed to measure the zone of inhibition.   Results: Extracts of L. inermis displayed noteworthy antimicrobial activity against E. fecalis. The zone of inhibition of henna against E. fecalis was found to be 11mm whereas the positive control had 14mm.   Conclusion: In conclusion, the henna extracts had shown acceptable antimicrobial efficacy and thus this study provides the scientific reason for the use of L. inermis in dentistry.

Prevalence of Dental Caries among Different Socioeconomic Status and their Treatment Needs among 5-15-year-old School-going Children in Maduravoyal Area, Chennai

Dental cariology is a discipline with history as long as that of human civilization. It has seen numerous growth and decline phases from the epidemiological perspective. Nevertheless, despite huge amounts of funds being allotted by various international agencies to estimate the prevalence and assess the treatment needs, there always exists a gap between collected data and actual scenarios due to the in-availability of feasible approaches to include all people as samples and assess the statistics, especially the rural population of developing countries. To solve this issue, investigators from various geographic denominations should come forward to present the situation in their dominion. This paper is a report on the prevalence of dental caries in school-going children aged 5-15 years, belonging to various socioeconomic strata. These results have testified to the positive correlation between increased westernization and the prevalence of dental caries. It is also seen that lower economic strata have more predilection for a healthier diet and resultant low prevalence in dental caries. Thus, this study has thrown valuable light on epidemiological aspects of dental caries in Maduravoyal, Chennai-based rural population, which can be used for various planning activities. How to cite this article: Amudha S, Moses J, Vijayakumar M, e t al. Prevalence of Dental Caries among Different Socioeconomic Status and their Treatment Needs among 5-15-year-old School-going Children in Maduravoyal Area, Chennai. Int J Clin Pediatr Dent 2021;14(3):403-411.

Topical anesthesia for stainless steel crown tooth preparation in primary molars: a pilot study

Background

Placement of full-coverage restorations such as stainless steel crowns (SSCs) for pulpectomy treated primary molars is essential for successful outcomes. The tooth preparation process for SSCs can cause discomfort to gingival tissues since the crown should be seated 1 mm subgingivally. The purpose of this prospective trial was to compare the effectiveness of subgingival and transmucosal application of topical anesthetics on dental pain during SSC tooth preparation among 6- to 8-year-old children.

Methods

A consecutive sample of 27 children, aged 6-8 years, who required an SSC after pulp therapy in primary molars were randomly divided into three groups. Group A received infiltration anesthesia before tooth preparation for SSC placement, whereas in Group B and C, only topical anesthesia was applied subgingivally and transmucosally. Wong-Bakers Faces pain rating scale (WBFPS) scores were recorded after tooth preparation. Faces, Legs, Activity, Cry and Consolability (FLACC) scores were evaluated by two blinded and calibrated investigators through video recordings of the patient during tooth preparation. Data were tabulated, and inter-group comparisons were performed using the Kruskal-Wallis and analysis of variance tests.

Results

Out of the 27 participants, 48% were boys and 52% were girls, with an overall mean age of 6.83 years. Group A showed the least pain scores according to both the scales, followed by Group B and Group C. The pain intensity was statistically significant on both the pain scales with P = 0.003 for FLACC and P < 0.001 for WBFPS.

Conclusion

Subgingival application of topical anesthesia reduced pain to a certain extent but not as effectively as infiltration anesthesia during SSC tooth preparation in primary molars. Transmucosal application of topical anesthesia did not reduce discomfort when compared to the other two interventions.

Microleakage patterns of glass ionomer cement at cement-band and cement-enamel interfaces in primary teeth

Context

In-vitro studies of microleakage are an initial screening method to assess the maximum theoretical loss of sealing ability in-vivo.

Aims

Our objective was to determine and compare microleakage patterns of conventional glass ionomer cement (GIC) and resin-modified GIC (RMGIC) for band cementation.

Methods

Forty caries-free second primary molars were randomly divided into two groups of 20 teeth each. Preformed molar bands in the two groups were cemented to enamel with one of two types of cement: Conventional GIC (Fuji I, GC Corporation; Tokyo, Japan) and RMGIC (Fuji Plus, GC Corporation; Tokyo, Japan). A dye penetration method was used for microleakage evaluation. Microleakage was determined by a stereomicroscope for the cement-band and cement-enamel interfaces.

Statistical Analysis Used

Statistical analysis was performed with Kruskal-Wallis and Mann-Whitney U tests.

Results

The mean microleakage value for conventional GIC (Fuji I) at cement-band and cement-enamel interfaces was 2.41 mm and 2.15 mm, respectively. The mean microleakage value for RMGIC (Fuji Plus) at cement-band and cement-enamel interfaces was 0.44 mm and 0.46 mm, respectively. Compared to conventional GIC, RMGIC showed less microleakage at both cement-band and cement-enamel interfaces. P < 0.001 and it was statistically highly significant.

Conclusions

Bands cemented with RMGIC had significantly less microleakage between the cement-band and cement-enamel interfaces than conventional GIC.

Gene therapy with plasmids encoding IFN-β or IFN-α14 confers long-term resistance to HIV-1 in humanized mice

Because endogenous interferon type I (IFN-I) produced by HIV-1 infection might complicate the analysis of therapeutically administered IFN-I, we tested different humanized mouse models for induction of IFN-I during HIV-1 infection. While HIV-1 induced high levels of IFN-α in BLT mice, IFN-I was undetectable following infection in the Hu-PBL mouse model, in which only T cells expand. We therefore tested the effect of treatment with Pegylated IFN-2 (pegasys), in Hu-PBL mice. Pegasys prevented CD4 T cell depletion and reduced the viral load for 10 days, but the effect waned thereafter. We next expressed IFN-I subsets (IFN-α2, −α6, −α8, −α14, and −β) in Hu-PBL mice by hydrodynamic injection of plasmids encoding them and 2 days later infected the mice with HIV-1. CD4 T cell depletion was prevented in all subtypes of IFN-I-expressing mice by day 10. However, at day 40 post-infection, protection was seen in IFN-β- and IFN-α14-expressing mice, but not the others. The viral load followed an inverse pattern and was highest in control mice and lowest in IFN-β- and IFN-α14-expressing mice until day 40 after infection. These results show that gene therapy with plasmids encoding IFN-β and −α14, but not the commonly used −α2, confers long-term suppression of HIV-1 replication.

Design and Fabrication of Graphene Reinforced Polymer Conductive Patch-Based Inset Fed Microstrip Antenna

This work explores the design and fabrication of graphene reinforced polyvinylidene fluoride (PVDF) patch-based microstrip antenna. Primarily, antenna was designed at 6[Formula: see text]GHz frequency and simulation results were obtained using Ansoft HFSS tool. Later fabrication of antenna was carried out with graphene–PVDF films as conducting patch deposited on bakelite substrate and copper as ground plane. Graphene–PVDF films were prepared using solvent casting process. The radiation efficiency of fabricated microstrip patch antenna was 48% entailing it to be adapted as a practically functional antenna. Both simulated and the practical results were compared and analyzed.

A DNA Vaccine Protects Human Immune Cells against Zika Virus Infection in Humanized Mice

A DNA vaccine encoding prM and E protein has been shown to induce protection against Zika virus (ZIKV) infection in mice and monkeys. However, its effectiveness in humans remains undefined. Moreover, identification of which immune cell types are specifically infected in humans is unclear. We show that human myeloid cells and B cells are primary targets of ZIKV in humanized mice. We also show that a DNA vaccine encoding full length prM and E protein protects humanized mice from ZIKV infection. Following administration of the DNA vaccine, humanized DRAG mice developed antibodies targeting ZIKV as measured by ELISA and neutralization assays. Moreover, following ZIKV challenge, vaccinated animals presented virtually no detectable virus in human cells and in serum, whereas unvaccinated animals displayed robust infection, as measured by qRT-PCR. Our results utilizing humanized mice show potential efficacy for a targeted DNA vaccine against ZIKV in humans.

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Zika DNA vaccine elicits protective antibody response in humanized DRAG mice.

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Human myeloid cells and B cells are targets of Zika virus.

A Zika virus vaccine requires testing in human immune cells to determine its effectiveness. In this communication, we report that a DNA vaccine encoding Zika prM and E protein is able to elicit protective neutralizing antibodies against Zika virus in humanized DRAG mice, and that human myeloid cells and B cells are primary targets of Zika virus.

Combination of IL-10 and IL-2 induces oligoclonal human CD4 T cell expansion during xenogeneic and allogeneic GVHD in humanized mice

IL-10 is a crucial anti-inflammatory cytokine which can also exert a seemingly divergent immunostimulatory effects under certain conditions. We found high levels of the cytokine in a xenogeneic GVHD model where NOD-scid IL2rγcnull (NSG) mice were transplanted with human PBMCs in presence of IL-2. Presence of exogenous IL-10 altered the kinetics of IL-2 induced human T cell reconstitution in vivo, showing an initial delay, followed by rapid expansion. Further, compared to IL-2 alone, treatment with IL-2 in combination with IL-10 increased survival in most animals and completely protected ∼20% of mice from GVHD. Additionally, IL-2 induced expansion of both CD4⁺ and CD8⁺ xenoreactive T cells whereas a combination of IL-2 and IL-10 resulted in selective expansion of CD4⁺ T cells only. TCR Vβ repertoire analysis of CD4⁺ T cells showed that in contrast to IL-2 alone, simultaneous presence of both cytokines drastically reduced the Vβ repertoire of the expanded CD4⁺ T cells. Highly restricted Vβ usage was also observed when the cytokine combination was tested in an allogeneic GVHD model where NOD-scid IL2rγc^null mice expressing HLA-DR4 (NSG-DR4) were transplanted with purified CD4⁺ T cells from HLA-DR4 negative donors. Taken together, our results demonstrate that IL-10 can profoundly modulate the subset composition and repertoire of responding T cells during GVHD.

Recent advances in RNAi-based strategies for therapy and prevention of HIV-1/AIDS

RNA interference (RNAi) provides a powerful tool to silence specific gene expression and has been widely used to suppress host factors such as CCR5 and/or viral genes involved in HIV-1 replication. Newer nuclease-based gene-editing technologies, such as zinc finger nucleases (ZFN), transcription activator-like effector nucleases (TALEN) and the clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 system, also provide powerful tools to ablate specific genes. Because of differences in co-receptor usage and the high mutability of the HIV-1 genome, a combination of host factors and viral genes needs to be suppressed for effective prevention and treatment of HIV-1 infection. Whereas the continued presence of small interfering/short hairpin RNA (si/shRNA) mediators is needed for RNAi to be effective, the continued expression of nucleases in the gene-editing systems is undesirable. Thus, RNAi provides the only practical way for expression of multiple silencers in infected and uninfected cells, which is needed for effective prevention/treatment of infection. There have been several advances in the RNAi field in terms of si/shRNA design, targeted delivery to HIV-1 susceptible cells, and testing for efficacy in preclinical humanized mouse models. Here, we comprehensively review the latest advances in RNAi technology towards prevention and treatment of HIV-1.

Nondestructive evaluation of graphene-based strain sensor using Raman analysis and Raman mapping

The objective of this work is to use techniques such as Raman analysis and Raman mapping to confirm that graphene-based polyvinylidene fluoride (PVDF) composites can be used in strain sensing industrial applications. The Id/Ig ratio is used to predict the defect level of unstrained graphene-PVDF films with respect to strained graphene-PVDF films. By analyzing the intensity variations of band in the spectra, the defect level present in strained graphene-PVDF films compared with that of unstrained graphene-PVDF films can be predicted. Area mapping is also conducted to correlate the defect variation between unstrained and strained graphene-PVDF films. Raman results were compared with defect level and in turn with induced strain. As expected, results are in concurrence with one another, thereby providing complementary and confirmatory analysis of the results to measure strain.

Lentivirus pre-packed with Cas9 protein for safer gene editing

The CRISPR/Cas9 system provides an easy way to edit specific site/s in the genome and thus offers tremendous opportunity for human gene therapy for a wide range of diseases. However, one major concern is off-target effects, particularly with long-term expression of Cas9 nuclease when traditional expression methods such as via plasmid/viral vectors are used. To overcome this limitation, we pre-packaged Cas9 protein (Cas9P LV) in lentiviral particles for transient exposure and showed its effectiveness for gene disruption in cells, including primary T cells expressing specific single guide RNAs (sgRNAs). We then constructed an 'all in one virus' to express sgRNAs in association with pre-packaged Cas9 protein (sgRNA/Cas9P LV). We successfully edited CCR5 in TZM-bl cells by this approach. Using an sgRNA-targeting HIV long terminal repeat, we also were able to disrupt HIV provirus in the J-LAT model of viral latency. Moreover, we also found that pre-packaging Cas9 protein in LV particle reduced off-target editing of chromosome 4:-29134166 locus by CCR5 sgRNA, compared with continued expression from the vector. These results show that sgRNA/Cas9P LV can be used as a safer approach for human gene therapy applications.

Optimizing sgRNA structure to improve CRISPR-Cas9 knockout efficiency

Background

Single-guide RNA (sgRNA) is one of the two key components of the clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 genome-editing system. The current commonly used sgRNA structure has a shortened duplex compared with the native bacterial CRISPR RNA (crRNA)–transactivating crRNA (tracrRNA) duplex and contains a continuous sequence of thymines, which is the pause signal for RNA polymerase III and thus could potentially reduce transcription efficiency.

Results

Here, we systematically investigate the effect of these two elements on knockout efficiency and showed that modifying the sgRNA structure by extending the duplex length and mutating the fourth thymine of the continuous sequence of thymines to cytosine or guanine significantly, and sometimes dramatically, improves knockout efficiency in cells. In addition, the optimized sgRNA structure also significantly increases the efficiency of more challenging genome-editing procedures, such as gene deletion, which is important for inducing a loss of function in non-coding genes.

Conclusions

By a systematic investigation of sgRNA structure we find that extending the duplex by approximately 5 bp combined with mutating the continuous sequence of thymines at position 4 to cytosine or guanine significantly increases gene knockout efficiency in CRISPR-Cas9-based genome editing experiments.

Electronic supplementary material

The online version of this article (doi:10.1186/s13059-015-0846-3) contains supplementary material, which is available to authorized users.

HIV infection in humanized mice: role of type I interferon on disease progression (VIR9P.1139)

HIV and SIV disease progression is associated with chronic expression of type I IFN and IFN-stimulated genes. A recent study showed that a high-dose injection of IFN-1 early during primary SIV infection in the rhesus macaque model was protective, while neutralization of endogenous IFN-1 was deleterious. In contrast, in the same animal model, prolonged IFN-1 administration accelerated disease development in the chronic stage of the infection. To better understand the role of IFN-1 during HIV infection, we used humanized-PBL mouse model for this study. The advantage of this model is that there is no endogenous interferon production upon HIV infection, allowing analysis of IFN-1 therapy. Since continuous presence of IFN-1 is detrimental in the SIV model, we hypothesized that intermittent treatment with IFN-1 may be protective against HIV infection. To test this hypothesis, we carried out intermittent pegasys (peg-interferon alpha) treatment after HIV infection in human PBL infused NOD-scid IL2rγcnull (hu-PBL) mice. This treatment with pegasys diminished HIV replication and delayed CD4 depletion compared to control mice. To further test the role of IFN, we are currently using humanized BLT mouse model of HIV infection. HIV infection in BLT mice leads to continuous production of high levels of type-I IFNs; and thus, we are studying the effects of continuous or intermittent IFN blockade using type I IFN antagonist. The results will be discussed.

Targeting DNA vaccines to dendritic cells using a small peptide to enhance immune response (VAC4P.1110)

Dendritic cell targeting of antigens greatly enhances immunogenicity. Although there are several reagents (DEC205, Dectin-1, Langerin, Clec9, nanoparticle, etc) to target protein antigens to DCs, there is still no method to target DNA vaccines directly to DCs. Here we show that a small peptide derived from the rabies virus glycoprotein, fused to protamine residues (RVG-P) can target DNA to DCs resulting in enhanced T-cell and humoral responses. Targeted delivery of DNA vaccine encoding the immunodominant Vaccinia virus B8R gene to DCs with RVG-P was able to re-stimulate Vaccinia-specific memory T cells in vitro. Moreover, a single iv injection of B8R gene bound to RVG-P without any adjuvants was able prime a Vaccinia-specific T-cell response that was able to rapidly clear a subsequent Vaccinia virus challenge in mice. Finally, immunization of mice with a DNA vaccine encoding with West Nile virus (WNV) prM and E proteins via RVG-P elicited high titers of WN neutralizing antibodies that protected mice from lethal WNV challenge. Thus, RVG-P provides a tool to target DNA vaccines to DCs to elicit robust T-cell and humoral immune responses.

Gene array analysis of PD-1H overexpressing monocytes reveals a pro-inflammatory profile (INC2P.417)

We have previously reported that overexpression of Programmed Death -1 Homolog (PD-1H) in human monocytes leads to activation and spontaneous secretion of multiple pro inflammatory cytokines. Here we evaluated changes in monocytes gene expression after enforced PD-1H expression by gene array. Total RNA isolated from PD-1H-expressing and control monocytes were analyzed with human Illumina HT-12 v4 Expression BeadChip. Fold change of genes were confirmed by real time PCR. Data revealed alterations in 51 potential candidate genes that relate to immune response, cell adhesion and metabolism. Genes corresponding to pro-inflammatory cytokines showed the highest upregulation. Compared to vector control, PD-1H induced a 7, 3.2, 3.0, 5.8, 4.4 and 3.1 fold upregulation of TNF-α, IL-1beta, IFN-α, γ, λ and IL-27 respectively. Further, the difference was abrogated in presence of specific but not scrambled siRNA. The data are in agreement with our cytometric bead array analysis showing induction of proinflammatory cytokines, IL-6, IL-1β and TNF-α by PD-1H. Other genes related to inflammation, including transglutaminase 2, the transcription factor NF-kB (p65 and p50) and toll like receptors 3 and 4 were also upregulated 5, 4.5 and 2.5 fold respectively. The analysis also revealed a novel set of previously unreported genes that need to be further mined and validated. We conclude that PD-1H functions to enhance monocyte activation.

Enhancement of seed germination in stored seeds using different pre-sowing treatments in Bauhinia purpurea L

Bauhinia purpurea L. is one of the important avenue tree species used in garden, road side plantations and other places. Fresh seed produce good germination upto 75 to 100 per cent. Seeds of this species stored for five months produced less germination (38.00 %) and it could be due to seed dormancy. Hence, the present study was carried out to evaluate different seed treatments to enhance seed germination in stored seeds of B. purpurea. Treatment like soaking seeds in hot water for 2 min to 5 min followed by overnight soaking in normal water resultedin highest germination of about 59.00 per cent over control (40.00%). Significant variation for germination parameters such as mean daily germination, germination rate index and germination value as well as early seedling vigour was recorded among different pre-sowing treatments in stored seeds.

Targeting DNA vaccines to myeloid cells using a small peptide

Targeting DNA vaccines to dendritic cells (DCs) greatly enhances immunity. Although several approaches have been used to target protein Ags to DCs, currently there is no method that targets DNA vaccines directly to DCs. Here, we show that a small peptide derived from the rabies virus glycoprotein fused to protamine residues (RVG-P) can target DNA to myeloid cells, including DCs, which results in enhanced humoral and T-cell responses. DCs targeted with a DNA vaccine encoding the immunodominant vaccinia B8R gene via RVG-P were able to restimulate vaccinia-specific memory T cells in vitro. Importantly, a single i.v. injection of B8R gene bound to RVG-P was able to prime a vaccinia-specific T-cell response that was able to rapidly clear a subsequent vaccinia challenge in mice. Moreover, delivery of DNA in DCs was enough to induce DC maturation and efficient Ag presentation without the need for adjuvants. Finally, immunization of mice with a DNA-vaccine encoding West Nile virus (WNV) prM and E proteins via RVG-P elicited high titers of WNV-neutralizing Abs that protected mice from lethal WNV challenge. Thus, RVG-P provides a reagent to target DNA vaccines to myeloid cells and elicit robust T-cell and humoral immune responses.

Multiplexing seven miRNA-Based shRNAs to suppress HIV replication

Multiplexed miRNA-based shRNAs (shRNA-miRs) could have wide potential to simultaneously suppress multiple genes. Here, we describe a simple strategy to express a large number of shRNA-miRs using minimal flanking sequences from multiple endogenous miRNAs. We found that a sequence of 30 nucleotides flanking the miRNA duplex was sufficient for efficient processing of shRNA-miRs. We inserted multiple shRNAs in tandem, each containing minimal flanking sequence from a different miRNA. Deep sequencing of transfected cells showed accurate processing of individual shRNA-miRs and that their expression did not decrease with the distance from the promoter. Moreover, each shRNA was as functionally competent as its singly expressed counterpart. We used this system to express one shRNA-miR targeting CCR5 and six shRNA-miRs targeting the HIV-1 genome. The lentiviral construct was pseudotyped with HIV-1 envelope to allow transduction of both resting and activated primary CD4 T cells. Unlike one shRNA-miR, the seven shRNA-miR transduced T cells nearly abrogated HIV-1 infection in vitro. Additionally, when PBMCs from HIV-1 seropositive individuals were transduced and transplanted into NOD/SCID/IL-2R γc(-/-) mice (Hu-PBL model) efficient suppression of endogenous HIV-1 replication with restoration of CD4 T cell counts was observed. Thus, our multiplexed shRNA appears to provide a promising gene therapeutic approach for HIV-1 infection.

Characterization of programmed death-1 homologue-1 (PD-1H) expression and function in normal and HIV infected individuals

Chronic immune activation that persists despite anti-retroviral therapy (ART) is the strongest predictor of disease progression in HIV infection. Monocyte/macrophages in HIV-infected individuals are known to spontaneously secrete cytokines, although neither the mechanism nor the molecules involved are known. Here we show that overexpression of the newly described co-stimulatory molecule, PD1 homologue (PD-1H) in human monocyte/macrophages is sufficient to induce spontaneous secretion of multiple cytokines. The process requires signaling via PD-1H as cytokine secretion could be abrogated by deletion of the cytoplasmic domain. Such overexpression of PD-1H, associated with spontaneous cytokine expression is seen in monocytes from chronically HIV-infected individuals and this correlates with immune activation and CD4 depletion, but not viral load. Moreover, antigen presentation by PD-1H-overexpressing monocytes results in enhanced cytokine secretion by HIV-specific T cells. These results suggest that PD-1H might play a crucial role in modulating immune activation and immune response in HIV infection.

Human IL-10 exacerbates graft versus host disease in NOD-scid IL2rγcnull mice transplanted with human PBMCs (TRAN3P.910)

Dysregulated cytokine production plays an important role in the clinical manifestation of acute graft-versus-host disease (aGVHD) following allogeneic bone marrow transplantation (BMT). The role of IL-10, anti-inflammatory cytokine in GVHD pathogenesis remains ambiguous. There are reports showing both beneficial and adverse effects of this cytokine in GVHD progression. Hence to determine the role of IL-10 in GVHD progression, we expressed hIL-10 in NOD-scid IL2rγcnull mice (NSG) by hydrodynamic gene delivery and evaluated its effect on xeogenic GVHD manifestations. We demonstrate that hIL-10 is capable of accelerating the hPBMC induced xeno-GVHD in NSG mice. The marked human T cell infiltration and tissue destruction observed in presence of IL-10 suggest that human IL-10 potently activates and expands pathogenic human T cells with the capacity to induce xeno GVHD. The significant reduction in the number of human cells at the initial phase and robust expansion at later stage suggests that those escapes IL-10 mediated suppression is responsible for the development of xeno-GVHD. Taken together, our results demonstrate for the first time that xenografted human T cells expand in response to IL-10 and mediate tissue damage in xeno GVHD mouse model. These finding provide caution against using rhIL-10 as an immunosuppressive cytokine after allogenic BMT.

Impact of IL-2 and IL-10 on human CD4/CD8 T cell composition and Vβ repertoire in a mouse xenogenic GVHD model (TRAN1P.873)

High level of IL-10 is present in sera of patients with Graft-versus-host disease (GVHD) following allogenic bone marrow transplantation. Our studies with NSG mouse model of GVHD induced by transfer of human PBMCs also revealed high levels of IL-10 in the sera, particularly in presence of IL-2, which accelerates the disease. Blocking antibody to IL-10 was unable to protect the animals from GVHD progression. To directly test the effect of IL-10, GVHD was induced after hydrodynamic injection of plasmids encoding human IL-10 singly or in combination with IL-2. When administered alone, IL-10 treatment resulted in more severe GVHD manifestation. Further, in IL-2 accelerated GVHD, IL-10 was unable to ameliorate the course of the disease. There was a marked difference in the composition of the repopulating human T cells in blood and spleen of mice treated with IL-2 or IL-10 alone compared to a combination of the two cytokines. Singly, both cytokines induced expansion of CD4+ as well as CD8+ T cells with a relatively diverse repertoire but in combination, they induced large oligoclonal expansions of CD4+ T cells with very limited Vβ repertoire and near complete absence of CD8+ T cells. Taken together, our results demonstrate for the first time that IL-10 directly contributes to GVHD pathogenesis. Further, when used in combination with IL-2, IL-10 has a major impact on the repertoire of the responding T cells.

Newer gene editing technologies toward HIV gene therapy

Despite the great success of highly active antiretroviral therapy (HAART) in ameliorating the course of HIV infection, alternative therapeutic approaches are being pursued because of practical problems associated with life-long therapy. The eradication of HIV in the so-called "Berlin patient" who received a bone marrow transplant from a CCR5-negative donor has rekindled interest in genome engineering strategies to achieve the same effect. Precise gene editing within the cells is now a realistic possibility with recent advances in understanding the DNA repair mechanisms, DNA interaction with transcription factors and bacterial defense mechanisms. Within the past few years, four novel technologies have emerged that can be engineered for recognition of specific DNA target sequences to enable site-specific gene editing: Homing Endonuclease, ZFN, TALEN, and CRISPR/Cas9 system. The most recent CRISPR/Cas9 system uses a short stretch of complementary RNA bound to Cas9 nuclease to recognize and cleave target DNA, as opposed to the previous technologies that use DNA binding motifs of either zinc finger proteins or transcription activator-like effector molecules fused to an endonuclease to mediate sequence-specific DNA cleavage. Unlike RNA interference, which requires the continued presence of effector moieties to maintain gene silencing, the newer technologies allow permanent disruption of the targeted gene after a single treatment. Here, we review the applications, limitations and future prospects of novel gene-editing strategies for use as HIV therapy.

A statistical model for the ultrasonic backscattered echo from tissue containing microcalcifications

Microcalcifications, generally seen in B-mode breast images as bright spots, often point to the presence of malignancies. Currently, statistical models to describe the signal strengths from tissue containing microcalcifications rely on the Rician or Nakagami densities. Because the Nakagami density requires the existence of randomly located scatterers with random cross sections, microcalcifications manifesting as isolated strong scatterers in the scattering volume makes it less suitable. Additionally, the absence of any regularly spaced scatterers also makes the Rician density less suitable. In this work, it is proposed that a 3-parameter McKay density with heavier tails than the Nakagami density, and hence more severe intensity fluctuations (speckle), might be a better fit to describe echo from tissue containing microcalcifications. This density is developed using a physical description of scattering and its characteristics are explored through random number simulation. Results demonstrate that the McKay densities have higher levels of speckle quantified through the speckle factor than the corresponding gamma densities (Nakagami for the envelope). Some preliminary analysis of tissue-mimicking phantoms modified to include microcalcification-like regions shows that higher speckle factors (seen with the McKay density) can be used to isolate and display microcalcifications. It is expected that this novel approach based on the McKay density will lead to newer and simpler means to detect and identify microcalcifications in ultrasonic B-scans.

In vivo reconstitution of human natural T regulatory cells in NOD/SCID IL2rγcnull mice by expression of human IL-2 (P2174)

Regulatory T cells (TRegs) can suppress a wide range of immune cells, making them an ideal candidate for the treatment graft versus host disease (GVHD). The potential clinical translation of targeted therapy with in vitro expanded human nTRegs is being tested to prevent GVHD, which is a major cause for morbidity and mortality associated with hematopoietic stem cell transplantation. Their usefulness in therapy will depend on their capacity to survive, migrate and retain suppressive activity when introduced into a transplant recipient. The lack of a suitable animal model is a major impediment for investigating the behavior of adoptively transferred nTRegs in vivo. The aim of this study is to develop TRegs reconstituted humanized mice as a preclinical model for understanding their therapeutic usefulness in the transplantation setting. We show that injection of a plasmid encoding human IL-2 is necessary and sufficient for long term engraftment of in vitro expanded nTRegs in NOD-SCID IL2rγcnull mice. Furthermore, the reconstituted TRegs trafficked to different organs of the body and retained their characteristic suppressive function. Finally, in an IL-2 accelerated GVHD model, we show that these in vivo reconstituted TRegs are capable of preventing severe xenogenic response of human PBMCs. Thus, this novel hu-TReg mouse model offers a pre-clinical platform to study the in vivo function and stability of human nTRegs and their ability to modulate autoimmune diseases and GVHD.

Targeted delivery of HMGB1 siRNA to macrophages and dendritic cells for sepsis treatment in humanized mouse model (P6223)

Over expression cytokine by innate immune cells is thought to initiate multiple organ failure in murine models of sepsis. Whether human cytokine storm also plays a similar role is not clear. Here we show that human hematopoietic cells are required to induce sepsis-induced mortality following cecal ligation and puncture (CLP) in the severely immunodeficient NOD/SCID/IL2Rγ-/- mice and siRNA treatment to inhibit HMGB1 release by human macrophages and dendritic cells dramatically reduces sepsis-induced mortality. Following CLP, as compared to immunocompetent WT mice, NOD/SCID/IL2Rγ-/- mice did not show high levels of serum HMGB1 or murine proinflammatory cytokines and were relatively resistant to sepsis-induced mortality. In contrast, NOD/SCID/IL2Rγ-/- mice transplanted with human hematopoietic stem cells (humanized BLT mice) showed high serum levels of HMGB1 as well as multiple human, but not murine proinflammatory cytokines and uniformly succumbed, suggesting human cytokines are sufficient to induce organ failure in this model. Moreover, targeted delivery of HMGB1 siRNA to human macrophages and dendritic cells using a short AchR binding peptide (RVG-9R) effectively suppressed secretion of HMGB1, reduced the human cytokine storm, human lymphocyte apoptosis and rescued humanized mice from CLP-induced mortality. SiRNA treatment was also effective when started after the appearance of sepsis symptoms. These results show that: CLP in humanized mice provides a model to study human sepsis; HMGB1 siRNA might provide a treatment strategy for human sepsis; and RVG-9R provides a tool to deliver siRNA to human macrophages and dendritic cells that could potentially be used suppress a variety of human inflammatory diseases.

Long-term engraftment of human natural T regulatory cells in NOD/SCID IL2rγc(null) mice by expression of human IL-2

Regulatory T cells are essential to maintain immune homeostasis and prevent autoimmunity. Therapy with in vitro expanded human nT_Regs is being tested to prevent graft versus host disease, which is a major cause for morbidity and mortality associated with hematopoietic stem cell transplantation. Their usefulness in therapy will depend on their capacity to survive, migrate appropriately and retain suppressive activity when introduced into a transplant recipient. The lack of a suitable animal model for studying the in vivo reconstitutive capability of human nT_Regs is a major impediment for investigating the behavior of adoptively transferred nT_Regsin vivo. We show that injection of a plasmid encoding human IL-2 is necessary and sufficient for long term engraftment of in vitro expanded nT_Regs in NOD-SCID IL2rγc^null mice. We also demonstrate that these in vivo reconstituted T_Regs traffic to different organs of the body and retain suppressive function. Finally, in an IL-2 accelerated GVHD model, we show that these in vivo reconstituted T_Regs are capable of preventing severe xenogenic response of human PBMCs. Thus, this novel ‘hu-T_Reg mouse’ model offers a pre-clinical platform to study the in vivo function and stability of human nT_Regs and their ability to modulate autoimmune diseases and GVHD.

Comparison of the push-out shear bond strength of four types of glass ionomers when used to bond amalgam: An in vitro study

Background:

Dental amalgam is the primary direct posterior restorative material used worldwide, but it have certain shortcomings due to the lack of adhesiveness to the cavity. The introduction of the concept of bonded amalgam helped improve the use of amalgam as a restorative material.

Aim:

Evaluation of the comparative push-out shear bond strength of four types of conventional glass ionomers used to bond amalgam to tooth in simulated class I situations.

Materials and Methods:

Four chemical cure glass ionomers are used: GC Fuji I, GC Fuji II, GC Fuji III and GC Fuji VII, and are compared with unbonded amalgam. The push-out bond strength was tested using the Instron Universal Testing Machine at a crosshead speed of 0.5 mm/min.

Statistical Analysis:

One-way ANOVA and post hoc Bonferroni tests were used to analyze the data.

Results:

The results showed that the use of glass ionomer to bond amalgam resulted in an increase in the bond strength of amalgam. The Type VII glass ionomer showed the highest bond strength in comparison with the other glass ionomers.

Conclusions:

Conventional glass ionomer bonds to amalgam and shows a beneficial increase in the bond strength of the restoration in comparison with unbonded amalgam.

Improved siRNA/shRNA functionality by mismatched duplex

siRNA (small interfering RNA) and shRNA (small hairpin RNA) are powerful and commonly used tools in biomedical research. Currently, siRNAs are generally designed as two 21 nt strands of RNA that include a 19 nt completely complementary part and a 2 nt overhang. However, since the si/shRNAs use the endogenous miRNA machinery for gene silencing and the miRNAs are generally 22 nt in length and contain multiple internal mismatches, we tested if the functionality can be increased by designing the si/shRNAs to mimic a miRNA structure. We systematically investigated the effect of single or multiple mismatches introduced in the passenger strand at different positions on siRNA functionality. Mismatches at certain positions could significantly increase the functionality of siRNAs and also, in some cases decreased the unwanted passenger strand functionality. The same strategy could also be used to design shRNAs. Finally, we showed that both si and miRNA structured oligos (siRNA with or without mismatches in the passenger strand) can repress targets in all individual Ago containing cells, suggesting that the Ago proteins do not differentiate between si/miRNA-based structure for silencing activity.

Effect of 10% sodium ascorbate on the calcium: Phosphorus ratio of enamel bleached with 35% hydrogen peroxide: an in vitro quantitative energy-dispersive X-ray analysis

Objectives:

The study assessed quantitatively the calcium and phosphorous loss from the enamel surface following bleaching with 35% hydrogen peroxide and reversal with 10% sodium ascorbate using energy-dispersive X-ray analysis (EDAX).

Materials and Methods:

Eight non-carious, freshly extracted human permanent maxillary central incisors without any visible defects were used. Each specimen was bleached with 35% hydrogen peroxide activated by light and reversed with sodium ascorbate antioxidant gel. The calcium and phosphorous content in weight percent of sound, bleached and reversed enamel was acquired using EDAX. The Ca/P ratio was calculated from the obtained data. One-way ANOVA followed by Post Hoc Tukey test was used for comparing the Ca/P ratio of sound, bleached and reversed enamel.

Results:

All the samples subjected to bleaching using 35% hydrogen peroxide showed a statistically significant decrease in the Ca/P ratio as compared with samples in which no bleaching procedure was performed (P-value < 0.01). The striking finding was that there was a significant increase in the Ca/P ratio on application of sodium ascorbate antioxidant gel when compared with the bleached enamel (P-value < 0.01).

Conclusion:

The authors concluded that 35% hydrogen peroxide causes a significant decrease in the Ca/P ratio. This decrease in the Ca/P ratio can be restored by the application of 10% sodium ascorbate antioxidant gel.

Shear bond strengths of two dentin bonding agents with two desensitizers: An in vitro study

AIM

The aim of this in vitro study was to compare the shear bond strengths of two different dentin bonding agents with two different desensitizers.

MATERIALS AND METHODS

Eighty molars were taken which were ground to expose the dentin. The teeth were divided into two major groups. Each major group was subdivided into four subgroups of 10 samples each. Groups Ia and IIa were treated as dry bonding groups, groups Ib and IIb were treated as a moist bonding groups, groups Ic and IIc were rewetted with Gluma desensitizer, and groups Id and IId were rewetted with vivasens desensitizer. Major group I was treated with Gluma comfort bond and Charisma. Major group II was treated Prime and Bond NT and TPH. The samples were thermo cycled and shear bond test was performed using an Instron machine. The data were analyzed using one-way analysis of variance and Tukey's Honestly significant different test.

RESULTS

The results revealed that the specimens rewetted with Gluma desensitizer showed the highest shear bond strength compared to all other groups, irrespective of the bonding agent or composite resin used.

CONCLUSIONS

It can be concluded that rewetting with desensitizer provided better bond strength than the other groups.

Targeting the HIV entry, assembly and release pathways for anti-HIV gene therapy

Targeting the HIV entry and assembly pathways holds promise for development of novel anti-HIV gene therapy vectors. We characterized discrete dominant negative (DN) Gag and Envelope mutants for their anti-HIV-1 activity. We show here that capsid mutants (Q155N and Y164A) are more potent inhibitors of WT HIV than the matrix mutant 1GA. Both the Envelope mutants tested, V513E and R515A, were equally effective and a combination of Gag and Envelope DN genes significantly enhanced potency. Interestingly, the DN mutants acted at multiple steps in the virus life cycle rather than solely disrupting virus release or infection. Inhibition mediated by R515A could be partially attributed to the Envelope cytoplasmic tail, as deletion of R515A tail partially abrogated its DN effect. Finally, the Y164A/R515A double mutant expressed in a lentiviral vector was effective at inhibiting HIV replication in CD34+ hematopoietic stem cell-derived macrophages, demonstrating the therapeutic potential of our approach.

Humanized mice for studying human leukocyte integrins in vivo

Humanized mice have recently emerged as powerful translational animal models for studying human hematopoiesis, immune interactions, and diseases of the human immune system. Several important advances in the humanized mouse technology have been reported over the last few years, thereby resulting in improved engraftment, high levels of human chimerism, and sustained human hematopoiesis. This chapter describes the detailed procedures for generating various humanized mouse models including hu-PBL, hu-HSC, and BLT models and discusses considerations for choosing the appropriate model system.

Antibody-mediated delivery of siRNAs for anti-HIV therapy

RNA interference (RNAi) is a potent and specific gene silencing mechanism that utilizes small -double-stranded RNA intermediates (small interfering RNAs or siRNAs) to target homologous mRNA sequences for degradation. The therapeutic potential of RNAi for HIV infection has been demonstrated in many studies. However, successful clinical application of RNAi is contingent on developing practical strategies to deliver siRNA to the desired target cells and tissues. Recently, there has been significant progress towards developing reagents that selectively deliver exogenous siRNA to immune cells that are targeted by HIV or involved in viral pathogenesis, such as T cells, macrophages, and dendritic cells. Here, we describe details of two antibody-based strategies for systemic delivery of siRNA either specifically to T cells via the CD7 receptor or to multiple immune cell types via LFA-1, present on all leukocytes.

Enhanced induction of HIV-specific cytotoxic T lymphocytes by dendritic cell-targeted delivery of SOCS-1 siRNA

Dendritic cells (DCs) are potent antigen-presenting cells that play a critical role in the activation of T cells. RNA interference (RNAi)-mediated silencing of negative immunoregulatory molecules expressed by DCs may provide a strategy to enhance the potency of DC-based vaccines and immunotherapy. Ablation of suppressor of cytokine signaling-1 (SOCS-1) in antigen-presenting cells has been shown to enhance cellular immune response in mice. Here, we used a previously reported DC-targeting approach to deliver small interfering RNA (siRNA) against SOCS-1 to human myeloid-derived DCs (MDDCs). SOCS1-silencing in MDDCs resulted in enhanced cytokine responses to lipopolysaccharide (LPS) and a strong mixed-lymphocyte reaction. Moreover, only DCs treated with SOCS-1 siRNA, and not controls, elicited strong primary in vitro responses to well-characterized HLA-A*0201-restricted Melan-A/MART-1 and human immunodeficiency virus (HIV) Gag epitopes in naive CD8(+) T cells from healthy donors. Finally, stimulation of CD8(+) T cells from HIV-seropositive subjects with SOCS1-silenced DCs resulted in an augmented polyfunctional cytotoxic T-lymphocyte (CTL) response, suggesting that SOCS-1 silencing can restore functionally compromised T cells in HIV infection. Collectively, these results demonstrate the feasibility of DC3-9dR-mediated manipulation of DC function to enhance DC immunogenicity for potential vaccine or immunotherapeutic applications.

Targeted delivery of siRNA to macrophages for anti-inflammatory treatment

Inflammation mediated by tumor necrosis factor-alpha (TNF-alpha) and the associated neuronal apoptosis characterizes a number of neurologic disorders. Macrophages and microglial cells are believed to be the major source of TNF-alpha in the central nervous system (CNS). Here, we show that suppression of TNF-alpha by targeted delivery of small interfering RNA (siRNA) to macrophage/microglial cells dramatically reduces lipopolysaccharide (LPS)-induced neuroinflammation and neuronal apoptosis in vivo. Because macrophage/microglia express the nicotinic acetylcholine receptor (AchR) on their surface, we used a short AchR-binding peptide derived from the rabies virus glycoprotein (RVG) as a targeting ligand. This peptide was fused to nona-D-arginine residues (RVG-9dR) to enable siRNA binding. RVG-9dR was able to deliver siRNA to induce gene silencing in macrophages and microglia cells from wild type, but not AchR-deficient mice, confirming targeting specificity. Treatment with anti-TNF-alpha siRNA complexed to RVG-9dR achieved efficient silencing of LPS-induced TNF-alpha production by primary macrophages and microglia cells in vitro. Moreover, intravenous injection with RVG-9dR-complexed siRNA in mice reduced the LPS-induced TNF-alpha levels in blood as well as in the brain, leading to a significant reduction in neuronal apoptosis. These results demonstrate that RVG-9dR provides a tool for siRNA delivery to macrophages and microglia and that suppression of TNF-alpha can potentially be used to suppress neuroinflammation in vivo.