Cytokine and T cell responses in post-chikungunya viral arthritis: A cross-sectional study

OBJECTIVE

To define the relationship between chronic chikungunya post-viral arthritis disease severity, cytokine response and T cell subsets in order to identify potential targets for therapy.

METHODS

Participants with chikungunya arthritis were recruited from Colombia from 2019-2021. Arthritis disease severity was quantified using the Disease Activity Score-28 and an Arthritis-Flare Questionnaire adapted for chikungunya arthritis. Plasma cytokine concentrations (interleukin (IL)-1β, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12p70, IL-13, interferon-γ and tumor necrosis factor (TNF)) were measured using a Meso Scale Diagnostics assay. Peripheral blood T cell subsets were measured using flow cytometry.

RESULTS

Among participants with chikungunya arthritis (N = 158), IL-2 levels and frequency of regulatory T cells (Tregs) were low. Increased arthritis disease activity was associated with higher levels of inflammatory cytokines (IL-6, TNF and CRP) and immunoregulatory cytokine IL-10 (p<0.05). Increased arthritis flare activity was associated with higher Treg frequencies (p<0.05) without affecting T effector (Teff) frequencies, Treg/Teff ratios and Treg subsets. Finally, elevated levels of IL-2 were correlated with increased Treg frequency, percent Tregs out of CD4+ T cells, and Treg subsets expressing immunosuppressive markers, while also correlating with an increased percent Teff out of live lymphocytes (p<0.05).

CONCLUSION

Chikungunya arthritis is characterized by increased inflammatory cytokines and deficient IL-2 and Treg responses. Greater levels of IL-2 were associated with improved Treg numbers and immunosuppressive markers. Future research may consider targeting these pathways for therapy.

Achievement of Target Gain Larger than Unity in an Inertial Fusion Experiment

On December 5, 2022, an indirect drive fusion implosion on the National Ignition Facility (NIF) achieved a target gain G_{target} of 1.5. This is the first laboratory demonstration of exceeding "scientific breakeven" (or G_{target}>1) where 2.05 MJ of 351 nm laser light produced 3.1 MJ of total fusion yield, a result which significantly exceeds the Lawson criterion for fusion ignition as reported in a previous NIF implosion [H. Abu-Shawareb et al. (Indirect Drive ICF Collaboration), Phys. Rev. Lett. 129, 075001 (2022)PRLTAO0031-900710.1103/PhysRevLett.129.075001]. This achievement is the culmination of more than five decades of research and gives proof that laboratory fusion, based on fundamental physics principles, is possible. This Letter reports on the target, laser, design, and experimental advancements that led to this result.

Joint-specific rheumatoid arthritis fibroblast-like synoviocyte regulation identified by integration of chromatin access and transcriptional activity

The mechanisms responsible for the distribution and severity of joint involvement in rheumatoid arthritis (RA) are not known. To explore whether site-specific FLS biology might be associated with location-specific synovitis and explain the predilection for hand (wrist/metacarpal phalangeal joints) involvement in RA, we generated transcriptomic and chromatin accessibility data from FLS to identify the transcription factors (TFs) and pathways. Networks were constructed by integration of chromatin accessibility and gene expression data. Analysis revealed joint-specific patterns of FLS phenotype, with proliferative, migratory, proinflammatory, and matrix-degrading characteristics observed in resting FLS derived from the hand joints compared with hip or knee. TNF-stimulation amplified these differences, with greater enrichment of proinflammatory and proliferative genes in hand FLS compared with hip and knee FLS. Hand FLS also had the greatest expression of markers associated with an 'activated' state relative to the 'resting' state, with the greatest cytokine and MMP expression in TNF-stimulated hand FLS. Predicted differences in proliferation and migration were biologically validated with hand FLS exhibiting greater migration and cell growth than hip or knee FLS. Distinctive joint-specific FLS biology associated with a more aggressive inflammatory response might contribute to the distribution and severity of joint involvement in RA.

Comparison of toxicity of silver nanomaterials and silver nitrate on developing zebrafish embryos: Bioavailability, osmoregulatory and oxidative stress

The mechanisms of toxicity of engineered nanomaterials (ENMs) to the early life stages of freshwater fish, and the relative hazard compared to dissolved metals, is only partially understood. In the present study, zebrafish (Danio rerio) embryos were exposed to lethal concentrations of silver nitrate (AgNO₃) or silver (Ag) ENMs (primary size 42.5 ± 10.2 nm). The 96 h-LC₅₀ for AgNO₃ was 32.8 ± 0.72 μg Ag L^-1 (mean ± 95% CI) compared to 6.5 ± 0.4 mg L^-1 of the whole material for Ag ENMs; with the ENMs being orders of magnitude less toxic than the metal salt. The EC₅₀ for hatching success was 30.5 ± 1.4 μg Ag L^-1 and 6.04 ± 0.4 mg L^-1 for AgNO₃ and Ag ENMs, respectively. Further sub-lethal exposures were performed with the estimated LC₁₀ concentrations for both AgNO₃ or Ag ENMs over 96 h where about 3.7% of the total Ag as AgNO₃ was internalised, as measured by Ag accumulation in the dechorionated embryos. However, for the ENMs exposures, nearly all (99.8%) of the total Ag was associated with chorion; indicating the chorion as an effective barrier to protect the embryo in the short term. Calcium (Ca²⁺) and sodium (Na⁺) depletion was induced in embryos by both forms of Ag, but hyponatremia was more pronounced in the nano form. Total glutathione (tGSH) levels declined in embryos exposed to both Ag forms, but a superior depletion occurred with the nano form. Nevertheless, oxidative stress was mild as superoxide dismutase (SOD) activity stayed uniform and the sodium pump (Na⁺/K⁺-ATPase) activity had no appreciable inhibition compared to the control. In conclusion, AgNO₃ was more toxic to the early life stage zebrafish than the Ag ENMs, still differences were found in the exposure and toxic mechanisms of both Ag forms.

Evaluation of Listeria monocytogenes biofilms attachment and formation on different surfaces using a CDC biofilm reactor

Listeria monocytogenes can adapt, persist, and form biofilms on food premises surfaces, representing a challenge for food safety, since they led to disease transmission, food contamination and spoilage during production. Physical interventions (scrubbing and wiping) can help controlling formation, nevertheless when biofilms are formed, they are usually very resistant to current control strategies used in the food industry. Biofilm attachment and formation is influenced by environment characteristics, substrate properties and microbial motility. The purpose of this study was to evaluate the ability of L. monocytogenes to attach and form biofilms on different surfaces (wood, nylon, and polycarbonate) representative of the materials used during produce harvesting and storage. Multi-strain L. monocytogenes biofilms were grown in a CDC Biofilm reactor at 20 ± 2 °C up to 96-h and characterized for: a) attachment strength by enumerating cells after rinsing; b) hydrophobicity and interfacial tension by contact angle measurements; c) biofilm architecture by Laser Scanning Confocal Microscopy. All experiments were done in triplicate. Material, incubation, and solvent significantly affected the hydrophobicity and wetting properties of L. monocytogenes biofilms (P < 0.05). The type of material and incubation time significantly influenced hydrophobicity and wetting properties of L. monocytogenes biofilms (P < 0.05). Highest contact angle and lowest interfacial tension were observed on polycarbonate coupons. The data presented contributes to understanding Listeria biofilms grow on different surfaces commonly used in produce harvesting and storage. The data obtained in this study can be used when evaluating intervention strategies to control this pathogen in food premises.

Differences in toxicity and accumulation of metal from copper oxide nanomaterials compared to copper sulphate in zebrafish embryos: Delayed hatching, the chorion barrier and physiological effects

The mechanisms of toxicity of engineered nanomaterials (ENMs) to the early life stages of freshwater fish, and the relative hazard compared to dissolved metals, is only partially understood. In the present study, zebrafish embryos were exposed to lethal concentrations of copper sulphate (CuSO₄) or copper oxide (CuO) ENMs (primary size ∼15 nm), and then the sub-lethal effects investigated at the LC₁₀ concentrations over 96 h. The 96 h-LC₅₀ (mean ± 95% CI) for CuSO₄ was 303 ± 14 µg Cu L^-1 compared to 53 ± 9.9 mg L^-1 of the whole material for CuO ENMs; with the ENMs being orders of magnitude less toxic than the metal salt. The EC₅₀ for hatching success was 76 ± 11 µg Cu L^-1 and 0.34 ± 0.78 mg L^-1 for CuSO₄ and CuO ENMs respectively. Failure to hatch was associated with bubbles and foam-looking perivitelline fluid (CuSO₄), or particulate material smothering the chorion (CuO ENMs). In the sub-lethal exposures, about 42% of the total Cu as CuSO₄ was internalised, as measured by Cu accumulation in the de-chorionated embryos, but for the ENMs exposures, nearly all (94%) of the total Cu was associated with chorion; indicating the chorion as an effective barrier to protect the embryo from the ENMs in the short term. Both forms of Cu exposure caused sodium (Na⁺) and calcium (Ca²⁺), but not magnesium (Mg²⁺), depletion from the embryos; and CuSO₄ caused some inhibition of the sodium pump (Na⁺/K⁺-ATPase) activity. Both forms of Cu exposure caused some loss of total glutathione (tGSH) in the embryos, but without induction of superoxide dismutase (SOD) activity. In conclusion, CuSO₄ was much more toxic than CuO ENMs to early life stage zebrafish, but there are subtle differences in the exposure and toxic mechanisms for each substance.

Paralinguistic Privacy Protection at the Edge

Voice user interfaces and digital assistants are rapidly entering our lives and becoming singular touch points spanning our devices. These always-on services capture and transmit our audio data to powerful cloud services for further processing and subsequent actions. Our voices and raw audio signals collected through these devices contain a host of sensitive paralinguistic information that is transmitted to service providers regardless of deliberate or false triggers. As our emotional patterns and sensitive attributes like our identity, gender, well-being, are easily inferred using deep acoustic models, we encounter a new generation of privacy risks by using these services. One approach to mitigate the risk of paralinguistic-based privacy breaches is to exploit a combination of cloud-based processing with privacy-preserving, on-device paralinguistic information learning and filtering before transmitting voice data.

In this paper we introduce EDGY , a configurable, lightweight, disentangled representation learning framework that transforms and filters high-dimensional voice data to identify and contain sensitive attributes at the edge prior to offloading to the cloud. We evaluate EDGY’s on-device performance and explore optimization techniques, including model quantization and knowledge distillation, to enable private, accurate and efficient representation learning on resource-constrained devices. Our results show that EDGY runs in tens of milliseconds with 0.2% relative improvement in ‘zero-shot’ ABX score or minimal performance penalties of approximately 5.95% word error rate (WER) in learning linguistic representations from raw voice signals, using a CPU and a single-core ARM processor without specialized hardware.

HIV pre-exposure prophylaxis adherence test using reverse transcription isothermal amplification inhibition assay

Current HIV antiretroviral therapy (ART) or pre-exposure prophylaxis (PrEP) therapy adherence monitoring relies on either patient self-reported adherence or monitored drug dispensing, which are not reliable. We report a proof-of-concept adherence monitoring assay which directly measures nucleotide reverse transcriptase inhibitor (NRTI) concentration using a reverse transcription isothermal amplification inhibition assay. We measure the concentration of Tenofovir diphosphate (TFV-DP) - an NRTI that functions as a deoxyadenosine triphosphate (dATP) analog and long-term adherence marker for PrEP - by measuring the inhibition of the reverse transcription of an RNA template. The completion or inhibition of reverse transcription is evaluated by recombinase polymerase amplification (RPA), an isothermal nucleic acid amplification assay commonly used for point-of-care diagnostics. We present and validate a model that predicts the amplification probability as a function of dATP and TFV-DP concentrations, nucleotide insertion sites on the RNA template, and RNA template concentration. The model can be used to rationally design and optimize the assay to operate at clinically relevant TFV-DP concentrations. We provide statistical analysis that demonstrates how the assay may be used as a qualitative or semi-quantitative tool for measuring adherence to NRTI drugs and used to support patient compliance. Due to its simple instrumentation and short runtime (<1 hour), this assay has the potential for implementation in low-complexity laboratories or point-of-care settings, which may improve access to ART and PrEP adherence monitoring.

Demonstrating the translocation of nanoplastics across the fish intestine using palladium-doped polystyrene in a salmon gut-sac

Fish are widely reported to ingest microplastics with low levels accumulating in the tissues, but owing to analytical constraints, much less is known about the potential accumulation of nanoplastics via the gut. Recently, the labelling of plastics with inorganic metals (e.g., palladium) has allowed measurements of nanoplastic uptake. The aim of the current study was to quantitatively assess the uptake of nanoplastics by the fish gut using palladium-doped nanoplastics (with a mean hydrodynamic radius of 202 ± 7 nm). By using an ex vivo gut sac exposure system, we show that in 4 h between 200 and 700 million nanoplastics (representing 2.5-9.4% of the administered nanoplastics dose) can enter the mucosa and muscularis layers of the intestine of salmon. Of the particles taken up, up to 700,000 (representing 0.6% of that taken into the tissue) of the nanoplastics passed across the gut epithelium of the anterior intestine and exit into the serosal saline. These data, generated in highly controlled conditions provide a proof-of-concept study, suggesting the potential for nanoplastics to distribute throughout the body, indicating the potential for systemic exposure in fish.

Polyvinyl chloride (PVC) plastic fragments release Pb additives that are bioavailable in zebrafish

Plastic polymers such as polyvinyl chloride (PVC) may contain chemical additives, such as lead (Pb), that are leachable in aqueous solution. The fragmentation into microplastics (MPs) of plastics such as PVC may facilitate desorption of chemical additives and increase exposure of aquatic animals. In this study, the role of chemical additives in the aqueous toxicity of PVC, high-density polyethylene (HDPE) and polyethylene terephthalate (PET) MPs were investigated in early-life stage zebrafish (Danio rerio) by assessment of changes in expression of biomarkers. Exposure of zebrafish larvae to PVC for 24 h increased expression of metallothionein 2 (mt2), a metal-binding protein, but no changes in expression of biomarkers of estrogenic (vtg1) or organic (cyp1a) contaminants were observed. HDPE and PET caused no changes in expression of any biomarkers. A filtered leachate of the PVC also caused a significant increase in expression of mt2 and indicated that a desorbed metal additive likely elicited the response in zebrafish. Metal release was confirmed by acid-washing the MPs which mitigated the response in mt2. Metal analysis showed Pb leached from PVC into water during exposures; at 500 mg PVC L^-1 in water, 84.3 ± 8.7 μg Pb L^-1 was measured after 24 h. Exposure to a Pb-salt at this concentration caused a comparable mt2 increase in zebrafish as observed in exposures to PVC. These data indicated that PVC MPs elicited a response in zebrafish but the effect was indirect and mediated through desorption of Pb from PVC into the exposure water. Data also indicated that PVC MPs may act as longer-term environmental reservoirs of Pb for exposure of aquatic animals; the Pb leached from PVC in 24 h in freshwater equated to 2.52% of total Pb in MPs leachable by the acid-wash. Studies of MPs should consider the potential role of chemical additives in toxicity observed.

SAT0003 ELEVATED BASELINE AND INCREASING AUTOANTIBODY LEVELS ARE ASSOCIATED WITH INCREASED RISK FOR IMMINENT ONSET OF INFLAMMATORY ARTHRITIS IN A PROSPECTIVELY STUDIED ANTI-CITRULLINATED PROTEIN ANTIBODY POSITIVE COHORT: THE TIP-RA COLLECTIVE

Background:

The Targeting Immune Responses for Prevention of RA (TIP-RA) Collaborative prospectively studies individuals at high risk for developing RA because of serum ACPA positivity in absence of baseline inflammatory arthritis (IA).

Objectives:

The objective of the analyses presented herein is to evaluate the role of baseline and changing levels of ACPA and rheumatoid factor (RF) in relationship to incident IA/RA.

Methods:

ACPA+ subjects and ACPA- controls were identified who did not have baseline historical or examination evidence of IA. ACPA+ was defined by serum elevation of anti-CCP3 ≥20 units (Inova). Subjects were evaluated annually or sooner if they had changes in joint symptoms. Factors including RFIgM and RFIgA (Inova) were also assessed, and relationships between autoantibody levels at baseline and over time and incident IA/RA were evaluated using t-tests, with paired testing where applicable.

Results:

Baseline characteristics of ACPA+ and ACPA- subjects are in Table 1. Sixteen of the 94 (17%) ACPA+ subjects developed IA/RA a mean of 518 days from the baseline visit; 14 of these met 2010 ACR/EULAR criteria for RA at the time of detection of IA. There was a trend for ACPA+ subjects who later developed IA/RA to have higher baseline levels of anti-CCP3 compared to those who did not develop IA/RA (Table 2). In addition, those who developed IA/RA had significantly higher mean levels of RFIgM and RFIgA compared to those who did not. While not statistically significant, in longitudinal analyses in the ACPA+ subjects with incident IA/RA, anti-CCP3 levels increased from baseline to identification of IA (mean [SD] of 119 [102] to 126 [100], p=0.42). Furthermore, RFIgM levels increased from 36 [49] at baseline to 43 [51] at the time of IA (p=0.31), and RFIgA levels increased from 16 [29] to 21 [31] (p=0.10). In contrast, in ACPA+ subjects who did not develop IA/RA, anti-CCP3 levels increased only slightly over follow-up of a mean of 712 days: 75 [75] to 80 [76], p=0.70 while the levels of RFIgM and RFIgA decreased slightly during the same follow-up: for RFIgM mean [SD] levels went from 9 [22] to 8 [19], p=0.74; for RFIgA, 5 [16] to 3 [12], p=0.67.

Table 1.

Baseline characteristics of ACPA+/- subjects

ACPA-(n=162)ACPA+(n=94)p-valueAge, mean58580.90% Female69680.67% Ever smoker33340.87RF-IgM, mean (SD)3.2 (10.0)13.5 (30.2)<0.01RF-IgA, mean (SD)0.3 (0.6)6.5 (19.1)<0.01Table 2.

Baseline characteristics of 16 ACPA+ subjects who developed incident IA/RA vs. 78 ACPA+ who did not

Did not develop IA/RA (n=78)Developed IA/RA (n=16)p-valueDays from baseline to IA/RA or follow-up, mean (SD)712 (124)518 (295)–% Meeting 2010 criteria at time of IA-88–CCP3, mean (SD)74.5 (75.3)119.1 (102.1)0.05RFIgM, mean (SD)9 (22)36 (49)<0.01RFIgA, mean (SD)4 (16)16 (29)0.03

Conclusion:

In this prospectively followed cohort of ACPA+ subjects, higher levels of RFIgM and RFIgA at baseline were significantly associated with development of IA/RA within the follow-up period. Furthermore, there was a trend for rising levels of anti-CCP3 and RFIgM and A to be associated with development of IA/RA. These finding support the use of higher and/or rising levels of autoantibodies as additional features to predict imminent onset of IA/RA in ACPA+ individuals as well as potentially to use as outcomes of success of preventive interventions. Furthermore, the trend of increasing levels of RFIgM and RFIgA over time in individuals who developed IA/RA suggests that targeting pathways of RF development may lead to preventive interventions in a subset of RA.

References:

None

Disclosure of Interests:

Kevin Deane Grant/research support from: Janssen, Consultant of: Inova, ThermoFisher, Janseen, BMS and Microdrop, Gary Firestein Grant/research support from: Lilly, Janssen, Abbvie, David Boyle: None declared, Jane Buckner Grant/research support from: Bristol-Myers Squibb, Janssen, Eddie A. James Grant/research support from: Janssen, Pfizer, Sanofi, Novartis, Sylvia Posso Grant/research support from: Janssen, William Robinson Grant/research support from: Janssen, Laurie K. Moss Grant/research support from: Janssen, Jennifer Seifert Grant/research support from: Janssen, Roger Gilmore Grant/research support from: Janssen, Saman Barzideh Grant/research support from: Janssen, Navin Rao Shareholder of: Janssen Pharmaceuticals, Employee of: Janssen Pharmaceuticals, Frederic Baribaud Shareholder of: Janssen Research & Development, LLC, Employee of: Janssen Research & Development, LLC, Sunil Nagpal Shareholder of: Janssen Pharmaceuticals, Employee of: Janssen Pharmaceuticals, Alyssa Johnsen Employee of: Janssen, V. Michael Holers Grant/research support from: Janssen, Celgene, and BMS

OP0337 DIFFERENTIAL METHYLATION OF PERIPHERAL BLOOD ADAPTIVE IMMUNE CELLS IN INDIVIDUALS AT HIGH RISK FOR RA AND WITH EARLY RA COMPARED WITH CONTROLS IDENTIFIES PATHWAYS IMPORTANT IN TRANSITION TO ARTHRITIS

Background:

The “Targeting Immune Responses for Prevention of RA” (TIP-RA) collaboration studies individuals at high risk for developing RA because of serum anti-citrullinated protein antibody positivity in absence of arthritis, and is focused on defining how they transition from at-risk to classifiable disease. One potential mechanism is through alterations in epigenetics patterns in adaptive immune cells.

Objectives:

Previous studies showed that DNA methylation patterns of early RA (ERA) synoviocytes differ from long-standing RA, suggesting that abnormal methylation occurs early in synovium and evolves over time. To extend these observations, we performed a cross-sectional analysis in TIP-RA of DNA methylation signatures in peripheral blood cells in ERA, at-risk anti-CCP3+ individuals and demographically matched CCP- controls.

Methods:

Genomic DNA was isolated from two independent cohorts of CCP- (cohorts 1 and 2, respectively: B cell: n = 17/34; memory T cell: n = 21/34; and naïve T cell: n = 21/33), CCP3+ (B cell: n = 18/37; memory T cell: n = 20/36; and naïve T cell: n = 20/35), and CCP3+ ERA (B cell: n = 4/18; memory T cell: n = 5/18; and naïve T cell: n = 5/18) after separating PBMCs using antibodies and magnetic beads. Methylation was measured by Illumina Infinium MethylationEPIC chip. Differentially methylated loci (DMLs) were identified using Welch’s t-test and mapped to gene promoter regions to define DM genes (DMGs). Principal component analysis (PCA) was used to represent relationship among groups. Pathway analysis was applied by Reactome.

Results:

For the initial cohort, 1494, 1097 and 1330 DMLs were identified among CCP+, CCP- and ERA in B cells, memory T cells and naïve T cells, respectively. For the confirmatory cohort, 523, 793 and 548 DMLs were found in corresponding cell populations. The DML overlap between the 2 cohorts was highly significant (p= 2.48E-77). The DMLs were combined for both groups and corresponded to 411, 412, and 351 DMGs in B cells, memory T cells and naïve T cells. Of these, we found 246, 198 and 195 DMGs between CCP3+ and ERA in each peripheral blood cell population, respectively. PCA showed separation of CCP+, CCP- and ERA in each of the three blood cell types by DMLs (Fig. 1). DMGs were mapped to biological pathways to identify DM pathways. Although most were not significant, there were several highly significant differences comparing CCP+, ERA and CCP- in memory T cells involving pathways, including “Interferon gamma signaling” (FDR 7.48E-14), “PD-1 signaling” (FDR 8.71E-10), “Translocation of ZAP-70 to Immunological synapse” (FDR 4.75E-10), and “Phosphorylation of CD3 and TCR zeta chains” (FDR 8.71E-10).

Figure 1.

PCA shows the separation of CCP+, CCP- and ERA patients in memory T cells in confirmatory cohort.

Conclusion:

We identified reproducible methylation signatures of CCP-, CCP+, and ERA in peripheral blood B cells, memory T cells and naïve T cells in initial and confirmatory cohorts. The methylome of ERA also demonstrated a distinctive pattern from CCP+, indicating that progression to RA is accompanied by epigenetic remodeling, especially in T cell signaling and interferon responses. These signatures identify critical pathways in CCP positivity and classifiable RA and could provide the basis of novel interventions to prevent disease.

Disclosure of Interests:

Rizi Ai: None declared, David Boyle: None declared, Deepa Hammaker: None declared, Kevin Deane Grant/research support from: Janssen, Consultant of: Inova, ThermoFisher, Janseen, BMS and Microdrop, V. Michael Holers Grant/research support from: Janssen, Celgene, and BMS, Andre Matti: None declared, William Robinson: None declared, Jane Buckner Grant/research support from: Bristol-Myers Squibb, Janssen, Navin Rao Shareholder of: Janssen Pharmaceuticals, Employee of: Janssen Pharmaceuticals, Frederic Baribaud Shareholder of: Janssen Research & Development, LLC, Employee of: Janssen Research & Development, LLC, Alyssa Johnsen Employee of: Janssen, Sunil Nagpal Shareholder of: Janssen Pharmaceuticals, Employee of: Janssen Pharmaceuticals, Wei Wang: None declared, Gary Firestein Grant/research support from: Lilly, Janssen, Abbvie

Exposure to Pb-halide perovskite nanoparticles can deliver bioavailable Pb but does not alter endogenous gut microbiota in zebrafish

Lead-halide perovskite nanoparticles (NPs) are a new technology, and investigation of toxicity is of considerable importance due to the potential lead (Pb) release into the environment. The aim of the study was to investigate aqueous and dietary toxicity of Pb-halide perovskite NP and Pb in zebrafish Danio rerio. Perovskite NP toxicity was evaluated in zebrafish by mortality, gene expression, histopathology, and phylogenetic analysis of gut microbiota. Zebrafish larvae were exposed to five Pb-halide perovskite NPs in parallel with Pb(NO₃)₂ exposures, and zebrafish adults were exposed to the three perovskite NPs that caused the strongest effect and Pb(NO₃)₂. No median lethal concentration (LC₅₀) was observed for zebrafish larvae exposed to up to 200 mg/L of perovskite NPs for 96 h. Mortality, metallothionein 2 (mt2) and δ-aminolevulinic acid dehydratase (ala-d) gene expression (24-h exposure) in zebrafish larvae after aqueous perovskite NPs exposures did not differ from total Pb concentration - response curves. The lack of differences in mortality and gene expression between perovskite NPs and soluble Pb after aqueous exposure suggest that toxicity from perovskite NPs can be attributed to bioavailable Pb rather than nano-specific effects. Induction of mt2 and reduction of ala-d expression levels in liver tissues showed Pb bioavailability after 2-d and 4-d dietary exposure to perovskite-spiked feeds. Changes in gut microbiota of adult zebrafish were detected after 14-d exposure to Pb-spiked food, but no changes were detected from perovskite-NP spiked food. The phylogenetic analysis identified different microbiome profiles of Pb-fed fish compared to perovskite-fed fish suggesting a different mechanism of toxicity. Exposure to Pb-halide perovskite NPs led to absorption of Pb likely from release of Pb ions rather than absorption of NPs. Pb-halide perovskite NPs can release bioavailable Pb and this needs to be considered during the development of this technology.

Toxicities of copper oxide nanomaterial and copper sulphate in early life stage zebrafish: Effects of pH and intermittent pulse exposure

Effort has been made to standardise regulatory ecotoxicity tests for engineered nanomaterials (ENMs), but the environmental realism of altered water quality and/or pulse exposure to these pollutants should be considered. This study aimed to investigate the relative toxicity to early life-stage zebrafish of CuO ENMs at acid pH and then under pulse exposure conditions, all compared to CuSO₄. At all pH values, CuSO₄ was more toxic to zebrafish than CuO ENMs. Additions of H⁺ were protective of CuSO₄ toxicity, with median lethal concentrations LC₅₀ (with 95% confidence intervals) of: 0.36 (0.33-0.40), 0.22 (0.20-0.24) and 0.27 (0.25-0.29) mg L^-1 at pH 5, pH 6 and pH 7, respectively. In contrast, the toxicity of CuO ENMs increased with acidity; LC₅₀ values were: 6.6 (4.5-8.5), 19.4 (11.6-27.2) and >100 mg L^-1 at pH 5, pH 6 and pH 7, respectively. The increased toxicity of the CuO ENMs in acid water corresponded with greater dissolution of dissolved Cu from the particles at low pH, suggesting free Cu²⁺ ion delivery to the zebrafish was responsible for the pH-effect. In continuous 96 h exposures to the substances at the LC₁₀ values and at pH 6, both CuSO₄ and CuO ENMs caused Cu accumulation, inhibition of Na⁺/K⁺-ATPase and depletion of total glutathione in zebrafish. However, two 24 h pulses of CuSO₄ or CuO ENMs at the same peak concentration caused similar effects to the continuous 96 h exposure, despite the shorter exposure durations of the former; suggesting that the pulses were more hazardous than the continuous exposure. In conclusion, the current water quality correction for pH with respect to Cu toxicity to freshwater fish should not be applied to the nano form. Crucially, CuO ENMs are more toxic in pulse than continuous exposure and new corrections for both water pH and the Cu exposure profile are needed for environmental risk assessment.

A Proposed Mechanism for Texture Property of Woody Breast in Broilers

ObjectivesWoody breast is a myopathy observed in chicken breast meat (Pectoralis major) characterized by its tough and rubbery texture. However, the exact causation of woody breast texture is still unknown. We hypothesize that sarcoplasmic reticulum (SR) dysfunctionality early postmortem results in rapid leakage of intracellular calcium may partially contribute to the abnormal meat texture observed in woody breast meat. The objective of this preliminary study was to investigate this hypothesis.Materials and MethodsFourteen Ross line broiler breast fillets (7 severe woody breast and 7 normal) were collected at 3 h postmortem from a commercial processing plant located in the southeast United States. The 7 woody breast samples also exhibited moderate to severe white striping. The 7 normal samples did not exhibit any signs of white striping or woody breast. Each sample was trimmed, weighed, vacuum packaged and frozen at –20°C at approximately 8 h postmortem. One 1.9 cm strip across the cranial end of each fillet was fabricated and pulverized in liquid nitrogen to measure sarcomere length (Laser Scan Confocal Microscope with a 100x/NA 1.4 objective), calpain activity (immunoblotting for µ-calpain autolysis), proteolysis (immunoblotting for troponin-T degradation) and collagen content (hydroxyproline content). Purge was also collected from each sample to evaluate protein (bicinchoninic acid assay) and free calcium concentration (atomic absorption).ResultsWoody breast fillets were heavier than normal chicken breast fillets (522.9 vs. 446.9g; P < 0.05). Woody breast samples tended to have shorter sarcomeres (1.70 vs. 2.02 µm; P = 0.0543) and less intact troponin-T compared to normal breast samples (relative intact troponin-T band density: 49.98 vs. 56.97%; P = 0.0515) at 8 h postmortem. It was interesting to note that no µ-calpain band was detected through immunoblotting for both the woody breast and normal samples at 8 h postmortem. Other studies have found similar results as poultry µ-calpain autolyzed at a much rapid rate than µ-calpain in mammalian species. In addition, the purge from woody breast samples also had higher levels of free calcium compared to normal samples (6.2 vs. 4.2 nmol calcium/mg protein; P < 0.05). Lastly, there was more collagen present in the woody breast samples compared to normal chicken breast samples (3.89 vs. 2.08 mg collagen/g muscle tissue; P < 0.05).ConclusionThe results indicated that the cause of texture abnormality of woody breast may be the combined effects of more calcium being released from the SR early postmortem resulting in shorter sarcomere length and more collagen being deposited in the chicken breast meat. Additional research with the focus on SR integrity and functionality as well as collagen crosslinks are needed to further elucidate the basic mechanism of woody breast texture formation.

Which attributes within target product profiles for tuberculosis diagnostics are the most important to focus on?

SETTING

New diagnostic tools for tuberculosis (TB) are urgently needed. To guide investment decisions, sufficient information regarding which test attributes are the most important for users and decision makers interested in introducing TB diagnostics should be made available.

OBJECTIVE

To rank test attributes in a target product profile (TPP) in order of importance for a sputum smear replacement test for TB.

DESIGN

An online survey was administered among 33 participants representing 14 of the 22 TB high-burden countries. Respondents included laboratory personnel, national TB program managers, donors, technical experts, patients and researchers. Participants were asked to rank 21 TPP test attributes in order of importance using a maximum-differential method that required ranking of relative trade-offs.

RESULTS

Sensitivity was ranked as the most important test attribute, followed by maintenance/calibration, reagent kit storage/stability, sample preparation steps and time to results.

CONCLUSION

Consulting widely regarding which TPP attributes are valued most by users and decision-makers involved in introducing TB diagnostics can assist TB test developers to prioritize their investments, and guide decision making if trade-offs are necessary.

Measurement of Nutritional and Inflammatory Biomarkers in Dry Plasma Spots (DPS) (P10-097-19)

Objectives

Conduct time and temperature stability experiments on Nutritional Biomarkers (NBs) and inflammation markers extracted from ViveBio Dry Plasma Spots (DPS).

Methods

Blood samples of 3 hematocrits (20, 30 and 45%) were created by combining purchased red blood cells (RBC) and sera. Blood samples of 35 µL were loaded onto ViveBio plasma separators. The underlying pads with plasma were stored at 45°, 23°, 4°, -20° and -70°C. Samples were tested on days 0, 1, 3, 7, 14, 28, 84 and 168.

Ferritin, Retinol Binding Protein (RBP4), soluble Transferrin Receptors (sTfR), Thyroglobulin (Tg), α-acid Glycoprotein (AGP), and C-Reactive Protein (CRP) were measured using the Quansys Biosciences, Q-Plex Micronutrient Array (Q-Plex). Values measured in the liquid sera were used as reference values for the DPS.

Red blood cell (RBC) folates and serum vitamin B12 were measured using a 96 well plate microbiological assay (ALPCO-Immundiagnostik AG).

25OH-Vitamin D3, Retinol, Methylmalonic acid (MMA) and Homocysteine (HCY) were measured using LC-MS/MS.

The Q-Plex was compared at 3 independent laboratories using a group of 80 whole blood samples, non-spiked and spiked with AGP, CRP, HRP2 and sTfR. Liquid plasma and extracted plasma from ViveBio pads were generated and stored at -80°C four weeks prior to assay.

Results

Overall, the measured values for Ferritin, RBP4, Tg, AGP, CRP, 25OH-D, Retinol and MMA decrease with increasing storage temperature and length of storage. Ferritin and Tg exhibited the best stability at 16.8% and 8.0% over a 6 month period. Vitamin B12 exhibited very poor stability declining to below the LOQ within day 3. Most of the NBs at 1 month correlated well with liquid plasma values (r2 = 0.42 to 0.99) (AGP at 23°C, r2 = 0.428; at -70°C r2 = 0.990 Ferritin stored at 23°C, r2 = 0.854; at -70°C r2 = 0.992; Thyroglobulin at 23°C, r2 = 0.916; at -70°C r2 = 0.830).

Conclusions

We have demonstrated that NBs can be analyzed in low volumes of DPS generated by the ViveBio plasma separator. The Q-Plex performed reproducibly on split samples among 3 labs. These tools offer great potential to improve nutritional assessment in population studies.

Funding Sources

Funding provided by the Bill and Melinda Gates foundation.

Human natural regulatory T cells recognize peptides of the heavy constant region of immunoglobulins presented by IgG+ B cells

Human natural regulatory T cells (nTreg) recognize conserved peptides derived from the heavy constant region of IgG (Fc). The fine specificity of nTreg and the immunodominance of peptides was determined in healthy donors and rheumatoid arthritis (RA) patients. Eight Fc peptides were identified as highly immunogenic in all subjects with similar ranking and four of eight bound multiple class II HLA alleles. These Fc peptides are presented by IgG+ B cells by internalization and processing of surface IgG and are recognized by Fc-specific nTreg from both healthy donors and RA patients. However, exogenous IgG processed by antigen presenting cells (APC) led to the expansion of this nTreg population only in healthy donors. While nTreg from patients with RA responded to Fc peptides, the response to exogenous IgG presented by APC was compromised. These results demonstrate a hole in the central adaptive immune regulation in RA.

Intravenous injection of unfunctionalized carbon-based nanomaterials confirms the minimal toxicity observed in aqueous and dietary exposures in juvenile rainbow trout (Oncorhynchus mykiss)

Numerous ecotoxicology studies of carbon-based nanomaterials (CNMs) have been conducted in fishes; however, different approaches have been used to make CNM dispersions and dose tanks for aqueous exposures, and to prepare food containing CNMs for dietary studies. This diversity of experimental methods has led to conflicting results and difficulties in comparing studies. The objective of the present study was to evaluate intravenous injection of unfunctionalized CNMs in rainbow trout (Oncorhynchus mykiss), as a means of delivering a known internal dose, on tissue biochemistry and histopathological lesions; then, subsequently, to compare the results with our previous work on aqueous and dietary exposures of rainbow trout to CNMs. Rainbow trout were injected in the caudal vein with corn oil dispersions of 200 μg (approximately 1 μg g^-1) of either the fullerene C₆₀, single-walled carbon nanotubes (SWCNTs), or amorphous carbon black. After 96 h, injected fish were euthanized and tissue samples collected for biochemistry and histology. Histological examination of the kidney of fish injected intravenously indicated the presence of black material consistent with the injected carbon treatments. However, there were no additional lesions associated with CNM exposure compared to controls. There were also no significant changes in haematology, or ionoregulatory disturbance in blood plasma among the intravenously injected fish. Significant elevation in lipid peroxidation (thiobarbituric acid reactive substances TBARS) was detected only in kidney and spleen of fish injected with SWCNTs, but not the other carbon treatments. The elevated TBARS following injection contrasted with CNMs delivered via aqueous or dietary routes in our previous studies, suggesting that the latter exposure routes may not lead to absorption and toxicity in the internal tissues. Comparison of the effects of injected CNMs with aqueous and dietary CNMs exposures indicates that these materials are of minimal environmentally-relevant toxicity in rainbow trout.

Do polyethylene microplastic beads alter the intestinal uptake of Ag in rainbow trout (Oncorhynchus mykiss)? Analysis of the MP vector effect using in vitro gut sacs

Microplastic (MP) vector effects have been well described in the literature but surprisingly little is in known about the impact of MPs on the intestinal uptake of contaminants. The present study aimed to determine whether the intestinal fate of Ag was affected by the presence of polyethylene MP beads. Ag (added as ^110mAg) was introduced into the lumen of rainbow trout (Oncorhynchus mykiss) anterior/mid-intestine gut sac preparations as Ag only, Ag and MPs (co-exposure) and Ag-incubated MPs (where Ag was adsorbed to the MP). Results show that after 3 h exposure the distribution of accumulated Ag between the four intestinal compartments (mucus layer, mucosal epithelium, muscle layer and serosal saline) was not affected by either MP condition when compared to Ag alone (p > 0.05, One way ANOVA). Across all treatment groups mucus layer binding dominated (54.2-72.6%) whereas relatively little Ag was transported to the blood compartment (i.e. combined muscle layer and serosal saline compartments, 8.5-15.0%). Accompanying adsorption/desorption studies were performed in relevant media. Over 24 h, 60.6± 2.9% of the available Ag in artificial freshwater adhered to the surface of the PE MPs. In pH adjusted luminal fluids (pH 2.2, 4.1, 7.4 and 9.8) that span the range of conditions encountered within the rainbow trout digestive tract, there was almost complete dissociation at acidic pHs within 3 h (<2% remaining on MPs at both pH 2.2 and pH 4.1). Such pHs are typical of piscine stomach. Based on our finding we suggest that following the ingestion of MPs with adsorbed pollutants, desorption would occur prior to entering the site of uptake. The MPs themselves have no impact on the trans-epithelial transport of the contaminant, but the net result of the MP vector effect is to potentially introduce labile contaminant forms into the intestine.

Identification of very small open reading frames in the genomes of Holmes Jungle virus, Ord River virus, and Wongabel virus of the genus Hapavirus, family Rhabdoviridae

Viruses of the family Rhabdoviridae infect a broad range of hosts from a variety of ecological and geographical niches, including vertebrates, arthropods, and plants. The arthropod-transmitted members of this family display considerable genetic diversity and remarkable genomic flexibility that enable coding for various accessory proteins in different locations of the genome. Here, we describe the genome of Holmes Jungle virus, isolated from Culex annulirostris mosquitoes collected in northern Australia, and make detailed comparisons with the closely related Ord River and Wongabel viruses, with a focus on identifying very small open reading frames (smORFs) in their genomes. This is the first systematic prediction of smORFs in rhabdoviruses, emphasising the intricacy of the rhabdovirus genome and the knowledge gaps. We speculate that these smORFs may be of importance to the life cycle of the virus in the arthropod vector.

"TORNADO" - Theranostic One-Step RNA Detector; microfluidic disc for the direct detection of microRNA-134 in plasma and cerebrospinal fluid

Diagnosis of seizure disorders such as epilepsy currently relies on clinical examination and electroencephalogram recordings and is associated with substantial mis-diagnosis. The miRNA, miR-134 (MIR134 in humans), has been found to be elevated in brain tissue after experimental status epilepticus and in human epilepsy cells and their detection in biofluids may serve as unique biomarkers. miRNAs from unprocessed human plasma and human cerebrospinal fluid samples were used in a novel electrochemical detection based on electrocatalytic platinum nanoparticles inside a centrifugal microfluidic device where the sandwich assay is formed using an event triggered release system, suitable for the rapid point-of-care detection of low abundance biomarkers of disease. The device has the advantage of controlling the rotation speed of the centrifugal device to pump nanoliter volumes of fluid at a set time and manipulate the transfer of liquids within the device. The centrifugal platform improves reaction rates and yields by proposing efficient mixing strategies to overcome diffusion-limited processes and improve mass transport rates, resulting in reduced hybridization times with a limit of detection of 1 pM target concentration. Plasma and cerebrospinal fluid samples (unprocessed) from patients with epilepsy or who experienced status epilepticus were tested and the catalytic response obtained was in range of the calibration plot. This study demonstrates a rapid and simple detection for epilepsy biomarkers in biofluid.

Cellular electrophysiological principles that modulate secretion from synovial fibroblasts

Rheumatoid arthritis (RA) is a progressive disease that affects both pediatric and adult populations. The cellular basis for RA has been investigated extensively using animal models, human tissues and isolated cells in culture. However, many aspects of its aetiology and molecular mechanisms remain unknown. Some of the electrophysiological principles that regulate secretion of essential lubricants (hyaluronan and lubricin) and cytokines from synovial fibroblasts have been identified. Data sets describing the main types of ion channels that are expressed in human synovial fibroblast preparations have begun to provide important new insights into the interplay among: (i) ion fluxes, (ii) Ca²⁺ release from the endoplasmic reticulum, (iii) intercellular coupling, and (iv) both transient and longer duration changes in synovial fibroblast membrane potential. A combination of this information, knowledge of similar patterns of responses in cells that regulate the immune system, and the availability of adult human synovial fibroblasts are likely to provide new pathophysiological insights.

Assessing Researcher Needs for a Virtual Biobank

INTRODUCTION

Biosamples and associated clinical data accelerate translational and clinical research discoveries. A lack of high quality biosamples both stalls projects and limits research advances. In this study, we targeted a wide audience of University of California (UC) biobanking stakeholders who were either involved with the collection or the utilization of biosamples to assess the scope of their biobanking activities and their interest in virtual biobanking or cooperating in the formation of the UC-wide biorepository.

MATERIALS AND METHODS

Each institutional review board from the five UC medical campuses' provided a dataset of potential researchers involved with biobanking. Once identified, a brief six item web-based questionnaire was administered electronically to these researchers.

RESULTS

Most survey participants (80%) responded "yes" (n = 348) that they were actively collecting biosamples for research, and 68% of participants indicated they would either definitely (30%, n = 131) or maybe (38%, n = 166) request biosample materials now or within the next year. An equal proportion of participants responded yes (42% or n = 184) and maybe (42% or n = 182) when asked if they would voluntarily contribute specimens to a UC-wide virtual biobank.

DISCUSSION

The results presented above show high levels of support among UC biobanking stakeholders for both requesting material from and contributing material to a UC-wide virtual biobank. In addition, a considerable number of individual researchers on our five UC medical campuses are conducting biospecimen research (i.e., well over n = 435 respondents).

Responsivity calibration of the LoWEUS spectrometer

We performed an in situ calibration of the relative responsivity function of the Long-Wavelength Extreme Ultraviolet Spectrometer (LoWEUS), while operating on the Lithium Tokamak Experiment (LTX) at Princeton Plasma Physics Laboratory. The calibration was accomplished by measuring oxygen lines, which are typically present in LTX plasmas. The measured spectral line intensities of each oxygen charge state were then compared to the calculated emission strengths given in the CHIANTI atomic database. Normalizing the strongest line in each charge state to the CHIANTI predictions, we obtained the differences between the measured and predicted values for the relative strengths of the other lines of a given charge state. We find that a 3rd degree polynomial function provides a good fit to the data points. Our measurements show that the responsivity between about 120 and 300 Å varies by factor of ∼30.

Breeding phenology and winter activity predict subsequent breeding success in a trans-global migratory seabird

Inter-seasonal events are believed to connect and affect reproductive performance (RP) in animals. However, much remains unknown about such carry-over effects (COEs), in particular how behaviour patterns during highly mobile life-history stages, such as migration, affect RP. To address this question, we measured at-sea behaviour in a long-lived migratory seabird, the Manx shearwater (Puffinus puffinus) and obtained data for individual migration cycles over 5 years, by tracking with geolocator/immersion loggers, along with 6 years of RP data. We found that individual breeding and non-breeding phenology correlated with subsequent RP, with birds hyperactive during winter more likely to fail to reproduce. Furthermore, parental investment during one year influenced breeding success during the next, a COE reflecting the trade-off between current and future RP. Our results suggest that different life-history stages interact to influence RP in the next breeding season, so that behaviour patterns during winter may be important determinants of variation in subsequent fitness among individuals.

Metabolomic profiling predicts outcome of rituximab therapy in rheumatoid arthritis

OBJECTIVE

To determine whether characterisation of patients' metabolic profiles, utilising nuclear magnetic resonance (NMR) and mass spectrometry (MS), could predict response to rituximab therapy. 23 patients with active, seropositive rheumatoid arthritis (RA) on concomitant methotrexate were treated with rituximab. Patients were grouped into responders and non-responders according to the American College of Rheumatology improvement criteria, at a 20% level at 6 months. A Bruker Avance 700 MHz spectrometer and a Thermo Scientific Q Exactive Hybrid Quadrupole-Orbitrap mass spectrometer were used to acquire (1)H-NMR and ultra high pressure liquid chromatography (UPLC)-MS/MS spectra, respectively, of serum samples before and after rituximab therapy. Data processing and statistical analysis were performed in MATLAB. 14 patients were characterised as responders, and 9 patients were considered non-responders. 7 polar metabolites (phenylalanine, 2-hydroxyvalerate, succinate, choline, glycine, acetoacetate and tyrosine) and 15 lipid species were different between responders and non-responders at baseline. Phosphatidylethanolamines, phosphatidyserines and phosphatidylglycerols were downregulated in responders. An opposite trend was observed in phosphatidylinositols. At 6 months, 5 polar metabolites (succinate, taurine, lactate, pyruvate and aspartate) and 37 lipids were different between groups. The relationship between serum metabolic profiles and clinical response to rituximab suggests that (1)H-NMR and UPLC-MS/MS may be promising tools for predicting response to rituximab.

Characterization of developmental Na(+) uptake in rainbow trout larvae supports a significant role for Nhe3b

Developing freshwater fish must compensate for the loss of ions, including sodium (Na(+)), to the environment. In this study, we used a radiotracer flux approach and pharmacological inhibitors to investigate the role of sodium/hydrogen exchange proteins (Nhe) in Na(+) uptake in rainbow trout (Oncorhynchus mykiss) reared from fertilization in soft water (0.1mM Na(+)). For comparison, a second group of embryos/larvae reared in hard water (2.2mM Na(+), higher pH and [Ca(2+)]) were also included in the experiment but were fluxed in soft water, only. Unidirectional rates of Na(+) uptake increased throughout development and were significantly higher in embryos/larvae reared in soft water. However, the mechanisms of Na(+) uptake in both groups of larvae were not significantly different, either in larvae immediately post-hatch or later in development: the broad spectrum Na(+) channel blocker amiloride inhibited 85-90% of uptake and the Nhe-inhibitor EIPA also caused near maximal inhibitions of Na(+) uptake. These data indicated Na(+) uptake was Nhe-mediated in soft water. A role of Nhe3b (but not Nhe2 or Nhe3a) in Na(+) uptake in soft water was also supported through gene expression analyses: expression of nhe3b increased throughout development in whole embryos/larvae in both groups and was significantly higher in those reared in soft water. This pattern of expression correlated well with measurements of Na(+) uptake. Together these data indicate that in part, rainbow trout embryos/larvae reared in low Na(+) soft water maintained Na(+) homeostasis by an EIPA sensitive component of Na(+) uptake, and support a primary role for Nhe3b.

Aqueous Hg(2+) associates with TiO2 nanoparticles according to particle size, changes particle agglomeration, and becomes less bioavailable to zebrafish

Engineered nanoparticles (NPs) have unique physicochemistry and potential to interact with other substances in the aqueous phase. Here, gene [metallothionein 2 (mt2)] expression changes in larval zebrafish were used to evaluate the association between aqueous Hg(2+) and TiO2 (NPs and bulk particle size control) to investigate the relationship between changes in Hg(2+) behavior and TiO2 size. During 24h exposures, TiO2 agglomerates increased in size and in the presence of 25μg Hg(2+)/L, greater increases in size were observed. The concentration of Hg(2+) in suspension also decreased in the presence of TiO2-NPs. Mercury increased expression of mt2 in larval zebrafish, but this response was lessened when zebrafish were exposed to Hg(2+) in the presence of TiO2-NPs, and which suggests that TiO2-NPs alter the bioavailability of Hg(2+) to zebrafish larvae. This ameliorative effect of TiO2 was also likely due to surface binding of Hg(2+) because a greater decrease in mt2 expression was observed in the presence of 1mg/L TiO2-NPs than 1mg/L TiO2-bulk. In conclusion, the results show that Hg(2+) will associate with TiO2-NPs, TiO2-NPs that have associated Hg(2+) will settle out of the aqueous phase more rapidly, and agglomerates will deliver associated Hg(2+) to sediment surfaces.

Sublethal effects of copper sulphate compared to copper nanoparticles in rainbow trout (Oncorhynchus mykiss) at low pH: physiology and metal accumulation

A few studies have investigated the interaction between copper toxicity and water pH in fishes, but little is known about the effects of acidic pH on the toxicity of copper nanoparticles (Cu-NPs). This study aimed to describe the sub-lethal toxic effects of Cu-NPs compared to CuSO4 at neutral and acidic water pH values in juvenile rainbow trout. Fish were exposed in triplicate (3 tanks/treatment) to control (no added Cu), or 20μgl(-1) of either Cu as CuSO4 or Cu-NPs, at pH 7 and 5 in a semi-static aqueous exposure regime for up to 7 days. Acidification of the water altered the mean primary particle size (at pH 7, 60±2nm and pH 5, 55±1nm) and dialysis experiments to measure dissolution showed an increased release of dissolved Cu from Cu-NPs at pH 5 compared to pH 7. Copper accumulation was observed in the gills of trout exposed to CuSO4 and Cu-NPs at pH 7 and 5, with a greater accumulation from the CuSO4 treatment than Cu-NPs at each pH. The liver also showed Cu accumulation with both Cu treatments at pH 7 only, whereas, the spleen and kidney did not show measurable accumulation of Cu at any of the water pH values. Exposure to acid water caused changes in the ionoregulatory physiology of control fish and also altered the observed effects of Cu exposure; at pH 5, branchial Na(+)/K(+)-ATPase activity was greater than at pH 7 and the inhibition of Na(+)/K(+)-ATPase activity caused by exposure to CuSO4 at pH 7 was also not observed. There were some changes in haematology and depletion of plasma Na(+) at pH 7 and 5 due to Cu exposure, but there were few material-type or pH effects. Overall, the data show that the accumulation of Cu is greater from CuSO4 than Cu-NPs; however, understanding of the effects of low pH on bioavailability of CuSO4 may not be directly transferred to Cu-NPs without further consideration of the physico-chemical behaviour of Cu-NPs in acid water.

Phase-selective graphene oxide membranes for advanced microfluidic flow control

For the first time, we harness the unique phase-selectivity of chip-integrated graphene oxide (GO) membranes to significantly enhance flow control on centrifugal microfluidic platforms. In this paper, we present novel processes for the assembly of these GO membranes into polymeric microfluidic systems and demonstrate that multilayer GO membranes allow the passage of water while blocking pressurized air and organic solutions.

Polymer-Coated Metal-Oxide Nanoparticles Inhibit IgE Receptor Binding, Cellular Signaling, and Degranulation in a Mast Cell-like Cell Line

Previous reports have shown that nanoparticles (NPs) can both enhance and suppress immune effector functions; however the mechanisms that dictate these responses are still unclear. Here, the effects of polyacrylic acid (PAA) functionalized metal-oxide NP are investigated on RBL-2H3 (representative mammalian granulocyte-like cell line) cell viability, cellular degranulation, immunoglobulin E (IgE) receptor binding, and cell signaling pathways related to immune function. The increasing development of PAA-NPs as pesticide dispersants and as drug carriers in therapeutics necessitates their investigation for safe production. Using two in vitro experimental approaches, this study demonstrates that pre-exposing RBL-2H3 cells, or IgE antibodies, to PAA-NPs (TiO₂, CeO₂, ZnO, Fe₂O₃, and PAA-Capsules (NP coating control) over 24 h, significantly decrease the binding capacity of IgE for Fcε receptors, inhibit the phosphorylation of intracellular signaling proteins (e.g., MAPK ERK) that mediate degranulation, and inhibited RBL-2H3 cell degranulation. In addition, and unlike the other NPs tested, PAA-TiO₂ significantly reduced RBL-2H3 viability, in a time (4-24 h) and dose-dependent manner (>50 μg mL^-1). Together, these data demonstrate that PAA-NPs at sub-lethal doses can interact with cell surface structures, such as receptors, to suppress various stages of the RBL-2H3 degranulatory response to external stimuli, and modify immune cell functions that can impact host-immunity.

Rosette Nanotubes Alter IgE-Mediated Degranulation in the Rat Basophilic Leukemia (RBL)-2H3 Cell Line

In this study, the effects of rosette nanotube (RNT) exposure on immune cell viability and function were investigated in vitro using the rat basophilic leukemia (RBL)-2H3 cell line. RBL-2H3 viability was decreased in a dose- and time-dependent manner after lysine-functionalized RNT (K-RNT) exposure. In addition, K-RNTs had a significant effect on RBL-2H3 degranulation. When K-RNT exposure was concurrent with IgE sensitization, 50 and 100 mg l(-1) K-RNTs elicited a heightened degranulatory response compared with IgE alone. Exposure to 50 and 100 mg l(-1) K-RNTs also caused degranulation in RBL-2H3 cells not sensitized with IgE (0 ng ml(-1) IgE). Furthermore, in cells preexposed to K-RNTs for 2 h and subsequently washed, sensitized, and stimulated with IgE, a potentiated degranulatory response was observed. Using confocal laser scanning microscopy and a fluorescein isothiocyanate (FITC)-functionalized RNT construct (termed FITC(1)/TBL(19)-RNT), we demonstrated a strong and direct affiliation between RNTs and RBL-2H3 cell membranes. We also demonstrated cellular internalization of RNTs after 2 h of exposure. Together, these data demonstrate that RNTs may affiliate with the cellular membrane of RBL-2H3 cells and can be internalized. These interactions can affect viability and alter the ability of these cells to elicit IgE-FcεR mediated degranulation.

Use of an exposure chamber to maintain aqueous phase nanoparticle dispersions for improved toxicity testing in fish

A novel chamber for maintaining aqueous phase dispersions of nanoparticles (NPs) to enable improved toxicity testing in larval zebrafish was developed. Aqueous concentrations were within 80% of initial NP concentrations, and the 96-h median lethal concentration (LC50) values were highly reproducible (coefficient of variation <0.16, n = 3 tests). Significantly lower toxicity for each NP tested (Ag, Cu, and TiO2 NPs) in static beakers suggested that traditional acute toxicity tests may underestimate aqueous phase toxicity of NPs.

Bioaccumulation and oxidative stress responses measured in the estuarine ragworm (Nereis diversicolor) exposed to dissolved, nano- and bulk-sized silver

The impact of Ag NPs on sediment-dwelling organisms has received relatively little attention, particularly in linking bioaccumulation to oxidative injury. The polychaete Nereis diversicolor was exposed to sediments spiked with dissolved Ag (added as AgNO3), Ag NPs (63 ± 27 nm) and larger bulk Ag particles (202 ± 56 μm), for up to 11 days at sublethal concentrations (nominally 2.5, 5, 10 μg Ag g(-1) sediment (dw)). There were concentration- and time-dependent differences in the accumulation of the three Ag forms, but all three forms elicited an oxidative stress response. In the cases of Ag NPs and bulk Ag particles, changes in antioxidant markers (glutathione, SOD, CAT, GPx, SeGPx, GST and GR) occurred without significant Ag accumulation. Differences in biomarker profiles between the three Ag forms suggest that the mechanism of oxidative stress caused by particulate Ag is distinct from that of dissolved Ag.

The role of acid-sensing ion channels in epithelial Na+ uptake in adult zebrafish (Danio rerio)

Acid-sensing ion channels (ASICs) are epithelial Na(+) channels gated by external H(+). Recently, it has been demonstrated that ASICs play a role in Na(+) uptake in freshwater rainbow trout. Here, we investigate the potential involvement of ASICs in Na(+) transport in another freshwater fish species, the zebrafish (Danio rerio). Using molecular and histological techniques we found that asic genes and the ASIC4.2 protein are expressed in the gill of adult zebrafish. Immunohistochemistry revealed that mitochondrion-rich cells positive for ASIC4.2 do not co-localize with Na(+)/K(+)-ATPase-rich cells, but co-localize with cells expressing vacuolar-type H(+)-ATPase. Furthermore, pharmacological inhibitors of ASIC and Na(+)/H(+)-exchanger significantly reduced uptake of Na(+) in adult zebrafish exposed to low-Na(+) media, but did not cause the same response in individuals exposed to ultra-low-Na(+) water. Our results suggest that in adult zebrafish ASICs play a role in branchial Na(+) uptake in media with low Na(+) concentrations and that mechanisms used for Na(+) uptake by zebrafish may depend on the Na(+) concentration in the acclimation medium.

TBX2 represses CST6 resulting in uncontrolled legumain activity to sustain breast cancer proliferation: a novel cancer-selective target pathway with therapeutic opportunities

TBX2 is an oncogenic transcription factor known to drive breast cancer proliferation. We have identified the cysteine protease inhibitor Cystatin 6 (CST6) as a consistently repressed TBX2 target gene, co-repressed through a mechanism involving Early Growth Response 1 (EGR1). Exogenous expression of CST6 in TBX2-expressing breast cancer cells resulted in significant apoptosis whilst non-tumorigenic breast cells remained unaffected. CST6 is an important tumor suppressor in multiple tissues, acting as a dual protease inhibitor of both papain-like cathepsins and asparaginyl endopeptidases (AEPs) such as Legumain (LGMN). Mutation of the CST6 LGMN-inhibitory domain completely abrogated its ability to induce apoptosis in TBX2-expressing breast cancer cells, whilst mutation of the cathepsin-inhibitory domain or treatment with a pan-cathepsin inhibitor had no effect, suggesting that LGMN is the key oncogenic driver enzyme. LGMN activity assays confirmed the observed growth inhibitory effects were consistent with CST6 inhibition of LGMN. Knockdown of LGMN and the only other known AEP enzyme (GPI8) by siRNA confirmed that LGMN was the enzyme responsible for maintaining breast cancer proliferation. CST6 did not require secretion or glycosylation to elicit its cell killing effects, suggesting an intracellular mode of action. Finally, we show that TBX2 and CST6 displayed reciprocal expression in a cohort of primary breast cancers with increased TBX2 expression associating with increased metastases. We have also noted that tumors with altered TBX2/CST6 expression show poor overall survival. This novel TBX2-CST6-LGMN signaling pathway, therefore, represents an exciting opportunity for the development of novel therapies to target TBX2 driven breast cancers.

Dietary selenomethionine influences the accumulation and depuration of dietary methylmercury in zebrafish (Danio rerio)

Methylmercury (MeHg) is a toxicant of concern for aquatic food chains. In the present study, the assimilation and depuration of dietary MeHg and the influence of dietary selenium on MeHg toxicokinetics was characterised in zebrafish (Danio rerio). In a triplicate tank experimental design (n=3 tanks per treatment group), adult zebrafish were exposed to dietary MeHg (as methylmercury-cysteine) at 5 and 10 μg/g and with or without selenium (as selenomethionine) supplemented to the diets at a concentration of 5 μg/g for 8 weeks followed by a 4-week depuration period. Methylmercury accumulated in muscle, liver and brain of zebrafish; with higher mercury concentrations in liver and brain than in muscle following 8 weeks of exposure. In muscle, the mercury concentrations were 3.4±0.2 and 6.4±0.1 μg/g ww (n=3) in zebrafish fed the 5 and 10 μg Hg/g diets, respectively. During the depuration period, mercury concentrations were significantly reduced in muscle in both the 5 and 10 μg Hg/g diet groups with a greater reduction in the high dose group. After depuration, the mercury concentrations were 2.4±0.1 and 4.0±0.3 μg/g ww (n=3) for zebrafish fed the 5 and 10 μg Hg/g diets, respectively. Data also indicated that supplemented dietary selenium reduced accumulation of MeHg and enhanced the elimination of MeHg. Lower levels of mercury were found in muscle of zebrafish fed MeHg and SeMet compared with fish fed only MeHg after 8 weeks exposure; the mercury concentrations in muscle were 5.8±0.2 and 6.4±0.1 μg/g ww (n=3) for zebrafish fed the 10 μg Hg/g+5 μg Se/g diet and the 10 μg Hg/g diet, respectively. Furthermore, the elimination of MeHg from muscle during the 4-week depuration period was significantly greater in the fish fed the diet containing SeMet compared to a control diet; the mercury concentrations were 3.3±0.1 and 4.0±0.3 μg/g ww (n=3) for zebrafish fed the 5 μg Se/g and the control diets, respectively. In summary, dietary SeMet reduces the accumulation and enhances the elimination of dietary MeHg in muscle of zebrafish.

Mechanisms of Cl(-) uptake in rainbow trout: cloning and expression of slc26a6, a prospective Cl(-)/HCO3(-) exchanger

In fresh waters, fishes continuously acquire ions to offset diffusive losses to a more dilute ambient environment and to maintain acid-base status. The objectives of the present study were to clone slc26a6, a prospective Cl(-)/HCO3(-) exchanger from rainbow trout, investigate its expression patterns in various tissues, at different developmental stages and after differential salinity exposure, and probe the mechanisms of Cl(-) uptake in rainbow trout embryos during development using a pharmacological inhibitor approach combined with (36)Cl(-) unidirectional fluxes. Results showed that the cloned gene encoded a 783 amino acid protein with conserved domains characteristic of the SLC26a family of anion exchange proteins. Phylogenetic analysis of this sequence against all subfamilies of the SLC26a family demonstrated that this translated protein shared a common ancestor with other actinopterygii and mammalian SLC26a6 isoforms and thus confirmed the identity of the cloned gene. Expression of slc26a6 was detected in all tissues and developmental stages assayed but was highest in the gill of juvenile trout. In trout embryos, Cl(-) uptake increased significantly post-hatch and was demonstrated to be mediated via an anion exchanger specific (DIDS sensitive) pathway that was also sensitive to hypercapnia. This parallels well with the predicted function of slc26a6, and the detection of the transcript in embryos and tissues of trout. In conclusion, this study is the first report of slc26a6 in rainbow trout and functional and expression analyses indicate its likely involvement in Cl(-)/HCO3(-) exchange in two life stages of rainbow trout.