Quantification of Bt-endotoxin exposure pathways in carabid food webs across multiple transgenic events

Despite the reported specificity of Bacillus thuringiensis proteins against target pests, a number of studies have indicated that the uptake of Bt-endotoxins from bioengineered crops could have negative effects on natural enemies. It is therefore essential to quantify exposure pathways in non-target arthropod food webs across multiple transgenic events. Adult ground beetles (Coleoptera: Carabidae) were collected from transgenic corn fields expressing lepidopteran-specific Cry1Ab, coleopteran-specific Cry3Bb1, and both Cry1Ab and Cry3Bb1 (stacked event), as well as a non-transgenic isoline. Carabid gut-contents were screened for Cry1Ab Bt-endotoxin using enzyme-linked immunosorbent assay. Significant numbers of carabids tested positive for Cry1Ab from the lepidopteran-specific field: Harpalus pensylvanicus (39%, 25 of 64), Stenolophus comma (4%, 6 of 136), Cratacanthus dubius (50%, 1 of 2), Clivina bipustulata (50%, 1 of 2), and Cyclotrachelus sodalis (20%, 1 of 5). The highest proportion of Bt-endotoxin uptake was 4–6 weeks post-anthesis. Only one species, H. pensylvanicus (5%, 4 of 75), screened positive for Cry1Ab from the stacked line, despite similar expression of this endotoxin in plant tissue harvested from both lines. This difference in Cry1Ab uptake could be due to changes in the non-target food web or differential rates of Bt-endotoxin decay between genetic events. This study has quantified the differential uptake of Cry1Ab Bt-endotoxin by the carabid community across multiple transgenic events, thus forming the framework for future risk-assessment of transgenic crops.     

Long-term survival and concomitant gene expression of ribozyme-transduced CD4+ T-lymphocytes in HIV-infected patients

BACKGROUND: An anti-HIV-1 tat ribozyme, termed Rz2, has been shown to inhibit HIV-1 infection/replication and to decrease HIV-1-induced pathogenicity in T-lymphocyte cell lines and normal peripheral blood T-lymphocytes. We report here the results of a phase I gene transfer clinical trial using Rz2. METHODS: Apheresis was used to obtain a peripheral blood cell population from each of four HIV-negative donors. After enrichment for CD4+ T-lymphocytes, ex vivo expansion and genetic manipulation (approximately equal aliquots of the cells were transduced with the ribozyme-containing (RRz2) and the control (LNL6) retroviral vector), these cells were infused into the corresponding HIV-1-positive twin recipient. Marking was assessed over an initial 24-week period and in total over an approximate 4-year period. RESULTS: The gene transfer procedure was shown to be safe, and technically feasible. Both RRz2- and LNL6-gene-containing peripheral blood mononuclear cells (PBMC) were detected at all time points examined to 4 years. There was concomitant gene construct expression in the absence of the need for ex vivo peripheral blood cell stimulation and there was no evidence of immune elimination of the neoR T-lymphocytes nor of silencing of the Moloney murine leukemia virus long terminal repeat. CONCLUSIONS: The proof of principle results reported here demonstrate safety and feasibility of this type of gene transfer approach. While not specifically tested, T-lymphocytes containing an anti-HIV gene construct may impact on HIV-1 viral load and CD4+ T-lymphocyte count, potentially representing a new therapeutic modality for HIV-1 infection.     

Toll-like receptor-7 agonist administered subcutaneously in a prolonged dosing schedule in heavily pretreated recurrent breast, ovarian, and cervix cancers

Background

The primary objective was to study the antitumor activity of prolonged subcutaneous dosing of systemic 852A, a Toll-like receptor-7 agonist (TLR-7), in recurrent breast, ovarian and cervix cancer. Secondary objectives included assessment of safety and immune system activation.

Methods

Adults with recurrent breast, ovarian or cervix cancer failing multiple therapies received 0.6 mg/m² of 852A subcutaneously twice weekly for 12 weeks. Doses increased by 0.2 mg/m²/week to a maximum of 1.2 mg/m². Serum was collected to assess immune activation.

Results

Fifteen patients enrolled: 10 ovarian, 2 cervix and 3 breast. Three completed all 24 injections. There were two grade 2 (decreased ejection fractions), nine grade 3 (1 cardiovascular, 1 anorexia, 3 dehydration, 2 infections, 2 renal) and two grade 4 (hepatic and troponin elevation) unanticipated toxicities. Cardiac toxicities included three cardiomyopathies (2 asymptomatic) and one stress-related non-ST elevated myocardial infarction. Five patients discontinued therapy due to possibly associated side effects. One who had stable disease (SD) following 24 doses received 17 additional doses. A cervix patient with SD following 24 doses received chemotherapy after progressing 3 months later, and remains disease free at 18 months. Immune activation, as evidenced by increased IP-10 and IL-1ra, was observed.

Conclusions

In this first human experience of a TLR-7 agonist delivered subcutaneously using a prolonged dosing schedule, 852A demonstrated sustained tolerability in some patients. Clinical benefit was modest, but immune activation was seen suggesting further study of antitumor applications is warranted. Because of cardiac toxicity; 852A should be used cautiously in heavily pretreated patients.     

In Vitro Evaluation of a Soluble Leishmania Promastigote Surface Antigen as a Potential Vaccine Candidate against Human Leishmaniasis

PSA (Promastigote Surface Antigen) belongs to a family of membrane-bound and secreted proteins present in several Leishmania (L.) species. PSA is recognized by human Th1 cells and provides a high degree of protection in vaccinated mice. We evaluated humoral and cellular immune responses induced by a L. amazonensis PSA protein (LaPSA-38S) produced in a L. tarentolae expression system. This was done in individuals cured of cutaneous leishmaniasis due to L. major (CCLm) or L. braziliensis (CCLb) or visceral leishmaniasis due to L. donovani (CVLd) and in healthy individuals. Healthy individuals were subdivided into immune (HHR-Lm and HHR-Li: Healthy High Responders living in an endemic area for L. major or L. infantum infection) or non immune/naive individuals (HLR: Healthy Low Responders), depending on whether they produce high or low levels of IFN-γ in response to Leishmania soluble antigen. Low levels of total IgG antibodies to LaPSA-38S were detected in sera from the studied groups. Interestingly, LaPSA-38S induced specific and significant levels of IFN-γ, granzyme B and IL-10 in CCLm, HHR-Lm and HHR-Li groups, with HHR-Li group producing TNF-α in more. No significant cytokine response was observed in individuals immune to L. braziliensis or L. donovani infection. Phenotypic analysis showed a significant increase in CD4+ T cells producing IFN-γ after LaPSA-38S stimulation, in CCLm. A high positive correlation was observed between the percentage of IFN-γ-producing CD4+ T cells and the released IFN-γ. We showed that the LaPSA-38S protein was able to induce a mixed Th1 and Th2/Treg cytokine response in individuals with immunity to L. major or L. infantum infection indicating that it may be exploited as a vaccine candidate. We also showed, to our knowledge for the first time, the capacity of Leishmania PSA protein to induce granzyme B production in humans with immunity to L. major and L. infantum infection.     

Regenerative capacity and biochemical composition of the sea star Luidia clathrata (Say) (Echinodermata: Asteroidea) under conditions of near-future ocean acidification

The present study examines sublethal effects of near-future (year 2100) ocean acidification (OA) on regenerative capacity, biochemical composition, and behavior of the sea star Luidia clathrata, a predominant predator in sub-tropical soft-bottom habitats. Two groups of sea stars, each with two arms excised, were maintained on a formulated diet in seawater bubbled with air alone (pH 8.2, approximating a pCO₂ of 380 μatm) or with a controlled mixture of air/C0₂ (pH 7.8, approximating a pCO₂ of 780 μatm). Arm length, total body wet weight, and righting responses were measured weekly. After 97 days, a period of time sufficient for 80% arm regeneration, pyloric caecal indices, and protein, carbohydrate, lipid, and ash levels were determined for body wall and pyloric caecal tissues of intact and regenerating arms of individuals held in both seawater pH treatments. The present study indicates that predicted near-term levels of ocean acidification (seawater pH 7.8) do not significantly impact whole animal growth, arm regeneration rates, biochemical composition, or righting behavior in this common soft bottom sea star.     

High-resolution imaging reveals indirect coordination of opposite motors and a role for LIS1 in high-load axonal transport

The specific physiological roles of dynein regulatory factors remain poorly understood as a result of their functional complexity and the interdependence of dynein and kinesin motor activities. We used a novel approach to overcome these challenges, combining acute in vivo inhibition with automated high temporal and spatial resolution particle tracking. Acute dynein inhibition in nonneuronal cells caused an immediate dispersal of diverse forms of cargo, resulting from a sharp decrease in microtubule minus-end run length followed by a gradual decrease in plus-end runs. Acute LIS1 inhibition or LIS1 RNA interference had little effect on lysosomes/late endosomes but severely inhibited axonal transport of large, but not small, vesicular structures. Our acute inhibition results argue against direct mechanical activation of opposite-directed motors and offer a novel approach of potential broad utility in the study of motor protein function in vivo. Our data also reveal a specific but cell type-restricted role for LIS1 in large vesicular transport and provide the first quantitative support for a general role for LIS1 in high-load dynein functions.     

Differential signaling by adaptor molecules LRP1 and ShcA regulates adipogenesis by the insulin-like growth factor-1 receptor

The low density lipoprotein receptor-related protein (LRP1) is a transmembrane receptor that integrates multiple signaling pathways. Its cytoplasmic domain serves as docking sites for several adaptor proteins such as the Src homology 2/α-collagen (ShcA), which also binds to several tyrosine kinase receptors such as the insulin-like growth factor 1 (IGF-1) receptor. However, the physiological significance of the physical interaction between LRP1 and ShcA, and whether this interaction modifies tyrosine kinase receptor signaling, are still unknown. Here we report that LRP1 forms a complex with the IGF-1 receptor, and that LRP1 is required for ShcA to become sensitive to IGF-1 stimulation. Upon IGF-1 treatment, ShcA is tyrosine phosphorylated and translocates to the plasma membrane only in the presence of LRP1. This leads to the recruitment of the growth factor receptor-bound protein 2 (Grb2) to ShcA, and activation of the Ras/MAP kinase pathway. Conversely, in the absence of ShcA, IGF-1 signaling bifurcates toward the Akt/mammalian target of rapamycin pathway and accelerates adipocyte differentiation when cells are stimulated for adipogenesis. These results establish the LRP1-ShcA complex as an essential component in the IGF-1-regulated pathway for MAP kinase and Akt/mammalian target of rapamycin activation, and may help to understand the IGF-1 signaling shift from clonal expansion to growth-arrested cells and differentiation during adipogenesis.     

A dual role for diacylglycerol kinase generated phosphatidic acid in autoantibody-induced neutrophil exocytosis

Dysregulated release of neutrophil azurophilic granules causes increased tissue damage and amplified inflammation during autoimmune disease. Antineutrophil cytoplasmic antibodies (ANCAs) are implicated in the pathogenesis of small vessel vasculitis and promote adhesion and exocytosis in neutrophils. ANCAs activate specific signal transduction pathways in neutrophils that have the potential to be modulated therapeutically to prevent neutrophil activation by ANCAs. We have investigated a role for diacylglycerol kinase (DGK) and its downstream product phosphatidic acid (PA) in ANCA-induced neutrophil exocytosis. Neutrophils incubated with the DGK inhibitor R59022, before treatment with ANCAs, exhibited a reduced capacity to release their azurophilic granules, demonstrated by a component release assay and flow cytometry. PA restored azurophilic granule release in DGK-inhibited neutrophils. Confocal microscopy revealed that R59022 did not inhibit translocation of granules, indicating a role for DGK during the process of granule fusion at the plasma membrane. In investigating possible mechanisms by which PA promotes neutrophil exocytosis, we demonstrated that exocytosis can only be restored in R59022-treated cells through simultaneous modulation of membrane fusion and increasing cytosolic calcium. PA and its associated pathways may represent viable drug targets to reduce tissue injury associated with ANCA-associated vasculitic diseases and other neutrophilic inflammatory disorders.     

Radiolabeling rhesus monkey CD34+ hematopoietic and mesenchymal stem cells with 64Cu-pyruvaldehyde-bis(N4-methylthiosemicarbazone) for microPET imaging

Noninvasive positron emission tomography (PET) provides a potential method for in vivo tracking of radiolabeled cells. The goal of this study was to assess the potential toxicity of 64Cu-pyruvaldehyde-bis(N4-methylthiosemicarbazone) (PTSM) on rhesus monkey CD34+ hematopoietic and mesenchymal stem cells in vitro in preparation for developing imaging protocols posttransplantation. CD34+ hematopoietic cells were radiolabeled with 0 to 40 microCi/mL 64Cu-PTSM and viability and colony formation were assessed. Rhesus monkey mesenchymal stem cells (rhMSCs) were placed in culture postradiolabeling for assessments of growth and differentiation toward adipogenic, osteogenic, and chondrogenic lineages. The results indicated that CD34+ cells radiolabeled with 20 microCi/mL and rhMSCs radiolabeled with 10 microCi/mL 64Cu-PTSM did not result in adverse effects on growth or differentiation. Nonradioactive copper was also evaluated and showed that the presence of copper was not harmful to the cells. CD34+ cells and rhMSCs radiolabeled with the optimized concentrations of 20 and 10 microCi/mL, respectively, were also assessed using the microPET scanner. Studies showed that a minimum of 2.50x10(4) CD34+ cells (1.1 pCi/cell) and 6.25x10(3) rhMSCs (4.4 pCi/cell) could be detected. These studies indicate that CD34+ hematopoietic cells and rhMSCs can be safely radiolabeled with 64Cu-PTSM without adverse cellular effects.