Single cell sequencing of zebrafish kidney marrows reveals AHR2-dependent endogenous regulation of hematopoiesis

The aryl hydrocarbon receptor (AHR) is a ligand-dependent transcription factor that mediates a wide range of biological and toxicological responses. While largely studied in ligand-activated toxicant responses, AHR also plays important roles in endogenous physiological processes. We leveraged single cell sequencing and an AHR2 knockout zebrafish line to investigate the role of AHR2 in regulating hematopoiesis (production and differentiation of red and white blood cells from hematopoietic stem cells). Our objectives were to determine if absence of AHR2-1) alters proportions of immune cell populations and/or 2) impacts gene expression within individual immune cell types. We dissected kidney marrow (organ of hematopoiesis in zebrafish) from adult wildtype and AHR2 knockout zebrafish (N=3/genotype), isolated single cells and sequenced ∼ 5000 cells/sample (10X Genomics). We identified 14 cell clusters representing the expected major blood (erythrocytes, thrombocytes), immune (B cells, macrophages, lymphoid cells, granulocytes, etc), progenitors and kidney cell populations. We focused our analyses only on the progenitor and mature immune cell types. While there were no genotype-specific differences in proportion of individual cell types, gene expression differences were observed within several cell types. For known genes, such as rrm2 , changes were up to 2000-fold, signifying their importance in AHR2-hematopoesis interaction. Several of the known genes are also identified as markers of carcinoma cells for an array of cancer types. However, many of the dysregulated genes are poorly annotated, limiting our ability to examine biological processes and pathways dysregulated on AHR2 mutation. Nevertheless, our study indicates that AHR2 plays an important endogenous role in hematopoiesis. Future work will focus on better characterizing anatomy of dysregulated genes and their functions in hematopoiesis.

Flame retardant tetrabromobisphenol A (TBBPA) disrupts histone acetylation during zebrafish maternal-to-zygotic transition

3,3',5.5'-Tetrabromobisphenol A (TBBPA) is a widely used brominated flame-retardant utilized in the production of electronic devices and plastic paints. The objective of this study is to use zebrafish as a model and determine the effects of TBBPA exposure on early embryogenesis. We initiated TBBPA exposures (0, 10, 20 and 40μM) at 0.75 h post fertilization (hpf) and monitored early developmental events such as cleavage, blastula and epiboly that encompass maternal-to-zygotic transition (MZT) and zygotic genome activation (ZGA). Our data revealed that TBBPA exposures induced onset of developmental delays by 3 hpf (blastula). By 5.5 hpf (epiboly), TBBPA-exposed (10-20 μM) embryos showed concentration-dependent developmental lag by up to 3 stages or 100% mortality at 40 μM. Embryos exposed to sublethal TBBPA concentrations from 0.75-6 hpf and raised in clean water to 120 hpf showed altered larval photomotor response (LPR), suggesting a compromised developmental health. To examine the genetic basis of TBBPA-induced delays, we conducted mRNA-sequencing on embryos exposed to 0 or 40 μM TBBPA from 0.75 hpf to 2, 3.5 or 4.5 hpf. Read count data showed that while TBBPA exposures had no overall impacts on maternal or maternal-zygotic genes, collective read counts for zygotically activated genes were lower in TBBPA treatment at 4.5 hpf compared to time-matched controls, suggesting that TBBPA delays ZGA. Gene ontology assessments for both time- and stage-matched differentially expressed genes revealed TBBPA-induced inhibition of chromatin assembly- a process regulated by histone modifications. Since acetylation is the primary histone modification system operant during early ZGA, we immunostained embryos with an H3K27Ac antibody and demonstrated reduced acetylation in TBBPA-exposed embryos. Leveraging in silico molecular docking studies and in vitro assays, we also showed that TBBPA potentially binds to P300- a protein that catalyzes acetylation- and inhibits P300 activity. Finally, we co-exposed embryos to 20 μM TBBPA and 50 μM n-(4-chloro-3-trifluoromethyl-phenyl)-2-ethoxy-6-pentadecyl-benzamide (CTPB) -a histone acetyltransferase activator that promotes histone acetylation- and showed that TBBPA-CTPB co or pre-exposures significantly reversed TBBPA-only developmental delays, suggesting that TBBPA-induced phenotypes are indeed driven by repression of histone acetylation. Collectively, our work demonstrates that TBBPA disrupts ZGA and early developmental morphology, potentially by inhibiting histone acetylation. Future studies will focus on mechanisms of TBBPA-induced chromatin modifications.

Equation of State and Thermometry of the 2D SU(N) Fermi-Hubbard Model

We characterize the equation of state (EoS) of the SU(N>2) Fermi-Hubbard Model (FHM) in a two-dimensional single-layer square optical lattice. We probe the density and the site occupation probabilities as functions of interaction strength and temperature for N=3, 4, and 6. Our measurements are used as a benchmark for state-of-the-art numerical methods including determinantal quantum Monte Carlo and numerical linked cluster expansion. By probing the density fluctuations, we compare temperatures determined in a model-independent way by fitting measurements to numerically calculated EoS results, making this a particularly interesting new step in the exploration and characterization of the SU(N) FHM.

Developmental Toxicity Assessment Using Zebrafish-Based High-Throughput Screening

Zebrafish-based high-throughput screening has been extensively used to study toxicological profiles of individual chemicals and mixtures, identify novel toxicants, and study modes of action to prioritize chemicals for further testing and policy decisions. Within this chapter, we describe a protocol for automated zebrafish developmental high-throughput screening in our laboratory, with emphasis on exposure setups, morphological and behavioral readouts, and quality control.

True coincidence summing correction for a BEGe detector in close geometry measurements

The true coincidence summing correction factor for a Broad Energy Germanium detector has been calculated at far and close geometry set-up using radioactive γ-ray sources. The correction factors were calculated using both experimental and analytical methods. Geant4 simulation was done to calculate the full-energy peak and total efficiencies of the detector. Standard, as well as fabricated mono-energetic γ-ray sources, were used for the γ-ray efficiency measurements. The simulated efficiencies of mono-energetic γ-ray sources were matched to the experimental γ-ray efficiencies by optimizing the detector parameters. The same parameters were used to obtain the full-energy peak and total efficiencies for γ-rays of current interest. Analytical and experimental correction factors were found to agree well with each other. The coincidence summing effect is found to be significant for source-to-detector distances less than 5 cm.

A CRISPR-Cas9 mutation in sox9b long intergenic noncoding RNA (slincR) affects zebrafish development, behavior, and regeneration

The role of long non-coding RNAs (lncRNAs) regulators of toxicological responses to environmental chemicals is gaining prominence. Previously, our laboratory discovered a lncRNA, sox9b long intergenic noncoding RNA (slincR), that is activated by multiple ligands of aryl hydrocarbon receptor (AHR). Within this study, we designed a CRISPR-Cas9-mediated slincR zebrafish mutant line to better understand its biological function in presence or absence of a model AHR ligand, 2,3,7,8 -Tetrachlorodibenzo-p-dioxin (TCDD). The slincRosu3 line contains an 18 bp insertion within the slincR sequence that changes its predicted mRNA secondary structure. Toxicological profiling showed that slincRosu3 is equally or more sensitive to TCDD for morphological and behavioral phenotypes. Embryonic mRNA-sequencing showed differential responses of 499 or 908 genes in slincRosu3 in absence or presence of TCDD Specifically, unexposed slincRosu3 embryos showed disruptions in metabolic pathways, suggesting an endogenous role for slincR. slincRosu3 embryos also had repressed mRNA levels of sox9b- a transcription factor that slincR is known to negatively regulate. Hence, we studied cartilage development and regenerative capacity- both processes partially regulated by sox9b. Cartilage development was disrupted in slincRosu3 embryos both in presence and absence of TCDD. slincRosu3 embryos also displayed a lack of regenerative capacity of amputated tail fins, accompanied by a lack of cell proliferation. In summary, using a novel slincR mutant line, we show that a mutation in slincR can have widespread impacts on gene expression and structural development endogenously and limited, but significant impacts in presence of AHR induction that further highlights its importance in the developmental process.

Complete Heparin Reversal by Protamine during Off-Pump Coronary Artery Bypass Surgery (OPCAB): A Necessity or Myth?

In our country majority of the coronary artery bypass surgery (CABG) are done off-pump and was reported having excellent clinical outcome along with cost efficiency by various investigators. Heparin is commonly used as most effective anticoagulant, and protamine sulfate is now generally used to reverse the anticoagulant action of heparin. While under dosing of protamine may result in incomplete heparin reversal and prolonged anticoagulation, protamine overdosing is associated with impaired clot formation exerted by the intrinsic anti-coagulation properties of protamine itself, moreover protamine administration is associated with mild to severe cardiovascular and pulmonary complications. Apart from traditional full neutralization of heparin now-a-days, half dose protamine was also introduced showing good outcome regarding lower activated clotting time (ACT), overall, less surgical bleeding with less transfusion. This comparative study was designed to detect differences between traditional and decreased protamine dosing in Off-Pump Coronary Artery Bypass (OPCAB) surgery. Four hundred (400) patients who underwent Off-Pump Coronary Artery Bypass Surgery (OPCAB) surgery at our institution over a period of 12 months were analyzed and were divided into two groups. Group A- received 0.5mg of protamine per 100 unit of heparin; Group B-received 1.0mg of protamine per 100 unit of heparin. ACT, blood loss, hemoglobin and platelet count units of blood and blood product transfusion requirements, clinical outcome and hospital stay were assessed in each patient. This study showed that 0.5mg of protamine per 100 unit of heparin was always able to reverse the anticoagulant effect of heparin with no significant difference in hemodynamic parameters, amount of blood loss and requirements of blood transfusion in between the groups. A standard protamine dosing formula (protamine-heparin at ratio of 1:1) adequate for on-pump cardiac surgical procedures significantly overestimates protamine requirements for OPCAB. Patients treated with decreased protamine do not appear to have adverse outcomes in terms of post-operative bleeding.

Tris(1,3-dichloro-2-propyl) phosphate disrupts the trajectory of cytosine methylation within developing zebrafish embryos

Tris (1,3-dichloro-2-propyl) phosphate (TDCIPP) is an organophosphate ester-based flame retardant widely used within the United States. Within zebrafish, initiation of TDCIPP exposure at 0.75 h post-fertilization (hpf) reliably disrupts cytosine methylation from cleavage (2 hpf) through early-gastrulation (6 hpf). Therefore, the objective of this study was to determine whether TDCIPP-induced effects on cytosine methylation persist beyond 6 hpf. First, we exposed embryos to vehicle or TDCIPP from 0.75 hpf to 6, 24, or 48 hpf, and then conducted bisulfite amplicon sequencing of a target locus (lmo7b) using genomic DNA derived from whole embryos. Within both vehicle- and TDCIPP-treated embryos, CpG methylation was similar at 6 hpf and CHG/CHH methylation were similar at 24 and 48 hpf (relative to 6 hpf). However, relative to 6 hpf within the same treatment, CpG methylation was lower within vehicle-treated embryos at 48 hpf and TDCIPP-treated embryos at 24 and 48 hpf - an effect that was driven by acceleration of CpG hypomethylation. Similar to our previous findings with DNA methyltransferase, we found that, even at high μM concentrations, TDCIPP had no effect on zebrafish and human thymine DNA glycosylase activity (a key enzyme that decreases CpG methylation), suggesting that TDCIPP-induced effects on CpG methylation are not driven by direct interaction with thymine DNA glycosylase. Finally, using 5-methylcytosine (5-mC)-specific whole-mount immunochemistry and automated imaging, we found that exposure to TDCIPP increased 5-mC abundance within the yolk of blastula-stage embryos, suggesting that TDCIPP may impact cytosine methylation of maternally loaded mRNAs during the maternal-to-zygotic transition. Overall, our findings suggest that TDCIPP disrupts the trajectory of cytosine methylation during zebrafish embryogenesis, effects which do not appear to be driven by direct interaction of TDCIPP with key enzymes that regulate cytosine methylation.

O-199 Couples presenting to Infertility clinics - Are they really infertile?

Study question

Are couples presenting to infertility clinics actually infertile, or is there an undiagnosed underlying sexual dysfunction whose treatment can lead to natural conception avoiding the need for assisted reproductive techniques?

Summary answer

All couples presenting with infertility should be asked about sexual function. If sexual dysfunction is diagnosed, a signicant proportion can achieve pregnancy without assisted reproduction

What is known already

Infertility is defined as the inability to conceive after one year of frequent and regular unprotected sexual intercourse (SI). Although sexual histories are a key part of primary care screening guidelines for infertility, they are often overlooked during the infertility work-up. It is postulated that a large proportion of couples presenting to infertility clinics have underlying sexual dysfunction. Treatment through specialist counselling for couples with sexual dysfunction can help achieve pregnancy, negating the need for complex assisted reproductive techniques such as intravaginal insemination (IVI) and intrauterine insemination (IUl).

Study design, size, duration

108 couples were recruited from a national fertility clinic. The duration of the study was 3.5 years, from January 2016 to August 2019. The study was based primarily on surveys, where diagnostic work-up for infertility included tools for measuring sexual dysfunction, such as the IIEF-15 questionnaire. Our objectives were to find the extent of improvement of SI before and after specialist referral, and the time to conceive (TTC) in those with and without sexual dysfunction.

Participants/materials, setting, methods

Couples who never had successful completion of SI (despite producing an ejaculate sample) prior to clinic attendance were included. Treatment via specialist referral was then offered to these patients.

Data were analysed to compare outcomes between those who subsequently had successful SI (“Group A”) and those who had not had successful SI (“Group B”). Both groups were counselled for fertility treatments, such as IVI and IUI. TTC between the groups was analysed using Kaplan-Meier analysis

Main results and the role of chance

Out of 2057 couples presenting to the Infertility Clinic, 128 (5.98%) had never had successful SI. From this, 108 couples were included in the study. Two-thirds of couples revealed sexual difficulties at the beginning of the initial consultation. In men, erectile dysfunction was the predominant cause (70.4%, n = 76). In women, dyspareunia was the leading problem (18.2%, N = 20). Fertility investigations, which included hormone profiles, revealed normal results in most cases.

Treatment via referral to specialist sexual counselling was offered to all couples. Only 33 couples reported successful SI during subsequent visits (Group A). 13 of these 33 couples went on to conceive (11 naturally, 1 by IUI and 1 by IVI). The rest (n = 75), who had no improvement (Group B), had a significantly longer duration of sexual dysfunction, which was also more severe. Out of these 75 couples, 8 conceived (0 naturally, 6 by IVI, and 2 by IUI).The IIEF-15 scores (index for sexual dysfunction) between groups A and B were 10.72 ± 4.28 vs. 8 ± 4.73, P-value 0.0142. Group A couples (less severe sexual dysfunction) conceived earlier than Group B (mean duration 27.2 weeks vs. 48.8 weeks log-rank P value <0.001).

Limitations, reasons for caution

The main limitations of this study include a small sample size and a small minority of couples refusing to undergo specialist counselling despite having sexual difficulties as they were only interested in assisted reproductive interventions such as IUl and IVI. These limitations hinder the internal/external validity of the study.

Wider implications of the findings

All couples presenting with infertility should be asked about sexual function. If sexual dysfunction is diagnosed, a signicant proportion can be helped to achieve pregnancy without assisted reproduction. In the cases of couples with persistent sexual difficulty, assisted reproductive techniques like IUI and IVI give a reasonable pregnancy rate.

Trial registration number

Not applicable

P-118 Timed Intercourse exacerbates the risk of sexual dysfunction in men & women without an improvement in time to pregnancy

Study question

Investigate the differences in sexual dysfunction and time to pregnancy between infertile couples pursuing timed intercourse and Regular Intercourse (RI at least twice a week).

Summary answer

TI significantly increased the risk of SD compared to RI for both males and females after adjusting all other contributing factors.

What is known already

Timed Intercourse (TI) involves aligning sexual intercourse to the time around ovulation to increase the chance of conception in couples trying to conceive. Whilst TI is often advocated to increase conception rates and potentially accelerate the time to pregnancy (TTP) for infertile couples, the stressful nature of this approach may be associated with adverse effects such as sexual dysfunction (SD) within the couple.

Study design, size, duration

This prospective cohort study recruited 371 infertile couples who had been trying to conceive for more than a year, presenting to three regional infertility clinics between January 2016 and December 2018. 283 couples pursued TI and 88 couples pursued RI for a year, with all couples having no pre-existing sexual or psychiatric illness, and no medical contraindications to frequent intercourse.

Participants/materials, setting, methods

The SD score of both partners was assessed at the first visit using the validated Arizona Sexual Experiences Scale (ASEX) and the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-V). TTP was determined using Kaplan Meier Analysis in couples for whom natural conception was possible and no reversible fertility pathology was identified.

Main results and the role of chance

Timed Intercourse (TI) involves aligning sexual intercourse to the time around ovulation to increase the chance of conception in couples trying to conceive. Whilst TI is often advocated to increase conception rates and potentially accelerate the time to pregnancy (TTP) for infertile couples, the stressful nature of this approach may be associated with adverse effects such as sexual dysfunction (SD) within the couple.

TI significantly increased the risk of SD compared to RI for both males (Odds ratio [OR] 15.24, 95% confidence interval [CI] 7.96-29.15) and females (OR 5.52, 95% CI 2.38- 12.78), after adjusting for age, medical disorders, obesity, smoking, cause of infertility, and previous assisted reproductive techniques. TI carried a higher risk of developing erectile dysfunction, premature ejaculation, male hypoactive sexual dysfunction, female sexual interest-arousal disorder, and female orgasmic disorder. The TTP for natural conception was similar between TI and RI (p = 0.1365).

Limitations, reasons for caution

TI, a well-known strategy for increasing conception rates, did not improve time to natural conception compared to regular sexual intercourse. In contrast, the risk of sexual dysfunction in both men and women was significantly higher in TI, compared with RI.

Wider implications of the findings

This large study raises the question of effectiveness of the long-held belief that TI (intercourse limited around the ovulation-time, based on different methods of ovulation-prediction) improves pregnancy outcomes.

Trial registration number

N/A

Role of power distance phenomena in blended learning in higher education post-Covid-19

COVID has posed several challenges for higher education. There is a rise in blended teaching and learning models that can improve the quality of education, observed Raman. Classroom interaction vital in quality of education is affected by power distance between the teacher and students, states Kasuya. Much research has been done on blended learning but hardly any on the role of power distance in blended learning in higher education, specifically post COVID. Keeping in mind the growing significance of blended learning shortly, it becomes strategically important to understand the role of power distance in blended learning in higher education post-COVID-19. This research paper tries to address the research gap. The study is exploratory, exploring the role of power distancing in blended learning formats during post-COVID-19. The findings indicate that there is a relationship between power distance and the autonomy of an individual. The higher the power distance between a teacher and a student from the teacher’s perspective, it becomes teacher-centred learning. So blended learning with the best of low power distances in terms of the media and delivery mechanism of offline and online ensures the mitigation of power between the teacher and the taught. The research will help the universities create a perfect blended learning format that enhances the quality of higher education. Due to the paucity of time and resources and a ban on respondent interaction due to pandemics, this research is based on secondary data analysis.

Transcriptomic and Long-Term Behavioral Deficits Associated with Developmental 3.5 GHz Radiofrequency Radiation Exposures in Zebrafish

The rapid deployment of the fifth-generation (5G) spectrum by the telecommunication industry is intended to promote better connectivity and data integration among various industries. However, concerns among the public about the safety and health effects of radiofrequency radiations (RFRs) emitted from the newer-generation cell phone frequencies remain, partly due to the lack of robust scientific data. Previously, we used developmental zebrafish to model the bioactivity of 3.5 GHz RFR, a frequency used by 5G-enabled cell phones, in a novel RFR exposure chamber. With RFR exposures from 6 h post-fertilization (hpf) to 48 hpf, we observed that, despite no teratogenic effects, embryos showed subtle hypoactivity in a startle response behavior assay, suggesting abnormal sensorimotor behavior. This study builds upon the previous one by investigating the transcriptomic basis of RFR-associated behavior effects and their persistence into adulthood. Using mRNA sequencing, we found a modest transcriptomic disruption at 48 hpf, with 28 differentially expressed genes. KEGG pathway analysis showed that biochemical pathways related to metabolism were significantly perturbed. Embryos were grown to adulthood, and then a battery of behavioral assays suggested subtle but significant abnormal responses in RFR-exposed fish across the different assays evaluated that suggest potential long-term behavioral effects. Overall, our study suggests the impacts of RFRs on the developing brain, behavior, and the metabolome should be further explored.

Realizing topological edge states with Rydberg-atom synthetic dimensions

A discrete degree of freedom can be engineered to match the Hamiltonian of particles moving in a real-space lattice potential. Such synthetic dimensions are powerful tools for quantum simulation because of the control they offer and the ability to create configurations difficult to access in real space. Here, in an ultracold ⁸⁴Sr atom, we demonstrate a synthetic-dimension based on Rydberg levels coupled with millimeter waves. Tunneling amplitudes between synthetic lattice sites and on-site potentials are set by the millimeter-wave amplitudes and detunings respectively. Alternating weak and strong tunneling in a one-dimensional configuration realizes the single-particle Su-Schrieffer-Heeger (SSH) Hamiltonian, a paradigmatic model of topological matter. Band structure is probed through optical excitation from the ground state to Rydberg levels, revealing symmetry-protected topological edge states at zero energy. Edge-state energies are robust to perturbations of tunneling-rates that preserve chiral symmetry, but can be shifted by the introduction of on-site potentials.

Synthetic dimensions, states of a system engineered to act as if they were a reconfigurable extra spatial dimension, have been demonstrated with different systems previously. Here the authors create a synthetic dimension using Rydberg atoms and configure it to support topological edge states.

Zebrafish Behavioral Assays in Toxicology

Zebrafish behavioral assays are commonly used to identify and study environmental stressors that elicit adverse effects on neurobehavior. Behavioral assay platforms are available for multiple life stages (embryonic, juvenile, and adults) and are robust in detecting stressor-induced acute effects on neurodevelopment as well as long term deficits in sensory mechanisms, social behavior, learning, memory, and neurodegenerative diseases. Within this chapter, we present an overview of zebrafish behavioral assays that are commonly used to study environmental neurotoxicants.

BOX engineering to mitigate negative differential resistance in MFIS negative capacitance FDSOI FET: an analog perspective

Till date, the existing understanding of negative differential resistance (NDR) is obtained from metal-ferro-metal-insulator-semiconductor (MFMIS) FET, and it has been utilized for both MFMIS and metal-ferro-insulator-semiconductor (MFIS) based NCFETs. However, in MFIS architecture, the ferroelectric capacitance (C_FE) is not a lumped capacitance. Therefore, for MFIS negative capacitance (NC) devices, the physical explanation which governs the NDR mechanism needs to be addressed. In this work, for the first time, we present the first principle explanation of the NDR effect in MFIS NC FDSOI. We found that the output current variation with the drain to source voltage (V_DS), (i.e.g_ds) primarily depends upon two parameters: (a)V_DSdependent inversion charge gradient (∂n/∂V_DS); (b)V_DSsensitive electron velocity (∂v/∂V_DS), and the combined effect of these two dependencies results in NDR. Further, to mitigate the NDR effect, we proposed the BOX engineered NC FDSOI FET, in which the buried oxide (BOX) layer is subdivided into the ferroelectric (FE) layer and the SiO₂layer. In doing so, the inversion charge in the channel is enhanced by the BOX engineered FE layer, which in turn mitigates the NDR and a nearly zerog_dswith a minimal positive slope has been obtained. Through well-calibrated TCAD simulations, by utilizing the obtained positiveg_ds, we also designed aV_DSindependent constant current mirror which is an essential part of analog circuits. Furthermore, we discussed the impact of the FE parameter (remanent polarization and coercive field) variation on the device performances. We have also compared the acquired results with existing literature on NC-based devices, which justifies that our proposed structure exhibits complete diminution of NDR, thus enabling its use in analog circuit design.

miR133b Microinjection during Early Development Targets Transcripts of Cardiomyocyte Ion Channels and Induces Oil-like Cardiotoxicity in Zebrafish (Danio rerio) Embryos

Previous studies have shown that altered expression of a family of small noncoding RNAs (microRNAs, or miRs) regulates the expression of downstream mRNAs and is associated with diseases and developmental disorders. miR133b is highly expressed in mammalian cardiac and skeletal muscle, and aberrant expression is associated with cardiac disorders and electrophysiological changes in cardiomyocytes. Similarly, cardiac dysfunction has been observed in early life-stage mahi-mahi (Coryphaena hippurus) exposed to crude oil, a phenotype that has been associated with an upregulation of miR133b as well as subsequent downregulation of a delayed rectifier potassium channel (I_Kr) and calcium signaling genes that are important for proper heart development during embryogenesis. To examine the potential role of miR133b in oil-induced early life-stage cardiotoxicity in fish, cleavage-stage zebrafish (Danio rerio) embryos were either (1) microinjected with ∼3 nL of negative control miR (75 μM) or miR133b (75 μM) or (2) exposed to a treatment solution containing 5 μM benzo(a)pyrene (BaP), a model polycyclic aromatic hydrocarbon, as a positive control. At 72 h post fertilization (hpf), miR133b-injected fish exhibited BaP-like cardiovascular malformations, including a significantly increased pericardial area relative to negative control miR-injected embryos, as well as a significantly reduced eye area. qPCR revealed that miR133b microinjection decreased the abundance of cardiac-specific I_Kr kcnh6 at 5 hpf, which may contribute to action potential elongation in oil-exposed cardiomyocytes. Additionally, ryanodine receptor 2, a crucial calcium receptor in the sarcoplasmic reticulum, was also downregulated by miR133b. These results indicate that an oil-induced increase in miR133b may contribute to cardiac abnormalities in oil-exposed fish by targeting cardiac-specific genes essential for proper heart development.

Triangle Singularity as the Origin of the a_{1}(1420)

The COMPASS Collaboration experiment recently discovered a new isovector resonancelike signal with axial-vector quantum numbers, the a_{1}(1420), decaying to f_{0}(980)π. With a mass too close to and a width smaller than the axial-vector ground state a_{1}(1260), it was immediately interpreted as a new light exotic meson, similar to the X, Y, Z states in the hidden-charm sector. We show that a resonancelike signal fully matching the experimental data is produced by the decay of the a_{1}(1260) resonance into K^{*}(→Kπ)K[over ¯] and subsequent rescattering through a triangle singularity into the coupled f_{0}(980)π channel. The amplitude for this process is calculated using a new approach based on dispersion relations. The triangle-singularity model is fitted to the partial-wave data of the COMPASS experiment. Despite having fewer parameters, this fit shows a slightly better quality than the one using a resonance hypothesis and thus eliminates the need for an additional resonance in order to describe the data. We thereby demonstrate for the first time in the light-meson sector that a resonancelike structure in the experimental data can be described by rescattering through a triangle singularity, providing evidence for a genuine three-body effect.

Utilizing Zebrafish Embryos to Reveal Disruptions in Dorsoventral Patterning

Dorsoventral (DV) patterning is a key landmark of embryonic development that is primarily regulated by bone morphogenetic protein (BMP) signaling. Disruption of DV patterning can result in downstream effects on cell specification and organogenesis. Zebrafish embryos have been extensively used to understand signaling pathways that regulate DV patterning because zebrafish embryos develop ex utero and, in contrast to mammalian embryos, which develop in utero, can be observed in real time using brightfield and fluorescence microscopy. Embryos with disrupted DV patterning are either dorsalized or ventralized, with lack of development of head or trunk/tail structures, respectively. Although these phenotypes are typically accompanied by effects on BMP signaling, exceptions exist where some drugs or environmental chemicals can disrupt DV patterning in the absence of effects on BMP signaling. Therefore, assessments of DV patterning should be accompanied by BMP signaling-specific readouts to confirm the role of BMP disruption. Here, we describe an exposure paradigm and steps for phenotyping zebrafish embryos for two types of DV defects, dorsalization and ventralization, with a range of severities. In addition, we describe a strategy for whole-mount immunohistochemistry of zebrafish embryos with an antibody specific for phospho-SMAD 1/5/9 (pSMAD 1/5/9), as disruption in pSMAD 1/5/9 localization is indicative of an effect on BMP signaling. Taken together, these protocols describe an initial strategy for evaluating DV patterning defects under various experimental conditions and confirming BMP-mediated DV patterning disruptions, which can be followed by additional studies that aim to uncover mechanisms leading to these adverse phenotypes. © 2021 Wiley Periodicals LLC. Basic Protocol 1: Phenotyping for dorsalization and ventralization Basic Protocol 2: Whole-mount immunohistochemistry with antibody to phospho-SMAD 1/5/9.

Effects of Phenanthrene Exposure on Cholesterol Homeostasis and Cardiotoxicity in Zebrafish Embryos

Polycyclic aromatic hydrocarbons (PAHs) are pervasive pollutants in aquatic ecosystems, and developing fish embryos are especially sensitive to PAH exposure. Exposure to crude oil or phenanthrene (a reference PAH found in oil) produces an array of gross morphological abnormalities in developing fish embryos, including cardiotoxicity. Recently, studies utilizing transcriptomic analyses in several oil-exposed fish embryos found significant changes in the abundance of transcripts involved in cholesterol biosynthesis. Given the vital role of cholesterol availability in embryonic heart development, we hypothesized that cholesterol dysregulation in early development contributes to phenanthrene-induced cardiotoxicity. We exposed zebrafish embryos to 12 or 15 µM phenanthrene from 6 to 72 h post fertilization (hpf) and demonstrated that, in conjunction with pericardial edema and bradycardia, several genes (fdft1 and hmgcra) in the cholesterol biosynthetic pathway were significantly altered. When embryos were pretreated with a cholesterol solution from 6 to 24 hpf followed by exposure to phenanthrene from 24 to 48 hpf, the effects of phenanthrene on heart rate were partially mitigated. Despite changes in gene expression, whole-mount in situ staining of cholesterol was not significantly affected in embryos exposed to phenanthrene ranging in stage from 24 to 72 hpf. However, the 2-dimensional yolk area was significantly increased with phenanthrene exposure at 72 hpf, suggesting that lipid transport from the yolk to the developing embryo was impaired. Environ Toxicol Chem 2021;40:1586-1595. © 2021 SETAC.

Phenotypically Anchored mRNA and miRNA Expression Profiling in Zebrafish Reveals Flame Retardant Chemical Toxicity Networks

The ubiquitous use of flame retardant chemicals (FRCs) in the manufacture of many consumer products leads to inevitable environmental releases and human exposures. Studying toxic effects of FRCs as a group is challenging since they widely differ in physicochemical properties. We previously used zebrafish as a model to screen 61 representative FRCs and showed that many induced behavioral and teratogenic effects, with aryl phosphates identified as the most active. In this study, we selected 10 FRCs belonging to diverse physicochemical classes and zebrafish toxicity profiles to identify the gene expression responses following exposures. For each FRC, we executed paired mRNA-micro-RNA (miR) sequencing, which enabled us to study mRNA expression patterns and investigate the role of miRs as posttranscriptional regulators of gene expression. We found widespread disruption of mRNA and miR expression across several FRCs. Neurodevelopment was a key disrupted biological process across multiple FRCs and was corroborated by behavioral deficits. Several mRNAs (e.g., osbpl2a) and miRs (e.g., mir-125b-5p), showed differential expression common to multiple FRCs (10 and 7 respectively). These common miRs were also predicted to regulate a network of differentially expressed genes with diverse functions, including apoptosis, neurodevelopment, lipid regulation and inflammation. Commonly disrupted transcription factors (TFs) such as retinoic acid receptor, retinoid X receptor, and vitamin D regulator were predicted to regulate a wide network of differentially expressed mRNAs across a majority of the FRCs. Many of the differential mRNA-TF and mRNA-miR pairs were predicted to play important roles in development as well as cancer signaling. Specific comparisons between TBBPA and its derivative TBBPA-DBPE showed contrasting gene expression patterns that corroborated with their phenotypic profiles. The newer generation FRCs such as IPP and TCEP produced distinct gene expression changes compared to the legacy FRC BDE-47. Our study is the first to establish a mRNA-miR-TF regulatory network across a large group of structurally diverse FRCs and diverse phenotypic responses. The purpose was to discover common and unique biological targets that will help us understand mechanisms of action for these important chemicals and establish this approach as an important tool for better understanding toxic effects of environmental contaminants.

B-cell clusters at the invasive margin associate with longer survival in early-stage oral-tongue cancer patients

In oral-cancer, the number of tumor-infiltrating lymphocytes (TILs) associates with improved survival, yet the prognostic value of the cellular composition and localization of TILs is not defined. We quantified densities, localizations, and cellular networks of lymphocyte populations in 138 patients with T1-T2 primary oral-tongue squamous cell carcinoma treated with surgical resections without any perioperative (chemo)radiotherapy, and correlated outcomes to overall survival (OS). Multiplexed in-situ immunofluorescence was performed for DAPI, CD4, CD8, CD20, and pan-cytokeratin using formalin-fixed paraffin-embedded sections, and spatial distributions of lymphocyte populations were assessed in the tumor and stroma compartments at the invasive margin (IM) as well as the center of tumors. We observed a high density of CD4, CD8, and CD20 cells in the stroma compartment at the IM, but neither lymphocyte densities nor networks as single parameters associated with OS. In contrast, assessment of two contextual parameters within the stroma IM region of tumors, i.e., the number of CD20 cells within 20 µm radii of CD20 and CD4 cells, termed the CD20 Cluster Score, yielded a highly significant association with OS (HR 0.38; p = .003). Notably, the CD20 Cluster Score significantly correlated with better OS and disease-free survival in multivariate analysis (HR 0.34 and 0.47; p = .001 and 0.019) as well as with lower local recurrence rate (OR: 0.13; p = .028). Taken together, our study showed that the presence of stromal B-cell clusters at IM, in the co-presence of CD4 T-cells, associates with good prognosis in early oral-tongue cancer patients.

A Review of the Functional Roles of the Zebrafish Aryl Hydrocarbon Receptors

Over the last 2 decades, the zebrafish (Danio rerio) has emerged as a stellar model for unraveling molecular signaling events mediated by the aryl hydrocarbon receptor (AHR), an important ligand-activated receptor found in all eumetazoan animals. Zebrafish have 3 AHRs-AHR1a, AHR1b, and AHR2, and studies have demonstrated the diversity of both the endogenous and toxicological functions of the zebrafish AHRs. In this contemporary review, we first highlight the evolution of the zebrafish ahr genes, and the characteristics of the receptors including developmental and adult expression, their endogenous and inducible roles, and the predicted ligands from homology modeling studies. We then review the toxicity of a broad spectrum of AHR ligands across multiple life stages (early stage, and adult), discuss their transcriptomic and epigenetic mechanisms of action, and report on any known interactions between the AHRs and other signaling pathways. Through this article, we summarize the promising research that furthers our understanding of the complex AHR pathway through the extensive use of zebrafish as a model, coupled with a large array of molecular techniques. As much of the research has focused on the functions of AHR2 during development and the mechanism of TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin) toxicity, we illustrate the need to address the considerable knowledge gap in our understanding of both the mechanistic roles of AHR1a and AHR1b, and the diverse modes of toxicity of the various AHR ligands.

The multi-dimensional embryonic zebrafish platform predicts flame retardant bioactivity

Flame retardant chemicals (FRCs) commonly added to many consumer products present a human exposure burden associated with adverse health effects. Under pressure from consumers, FRC manufacturers have adopted some purportedly safer replacements for first-generation brominated diphenyl ethers (BDEs). In contrast, second and third-generation organophosphates and other alternative chemistries have limited bioactivity data available to estimate their hazard potential. In order to evaluate the toxicity of existing and potential replacement FRCs, we need efficient screening methods. We built a 61-FRC library in which we systemically assessed developmental toxicity and potential neurotoxicity effects in the embryonic zebrafish model. Data were compared to publicly available data generated in a battery of cell-based in vitro assays from ToxCast, Tox21, and other alternative models. Of the 61 FRCs, 19 of 45 that were tested in the ToxCast assays were bioactive in our zebrafish model. The zebrafish assays detected bioactivity for 10 of the 12 previously classified developmental neurotoxic FRCs. Developmental zebrafish were sufficiently sensitive at detecting FRC structure-bioactivity impacts that we were able to build a classification model using 13 physicochemical properties and 3 embryonic zebrafish assays that achieved a balanced accuracy of 91.7%. This work illustrates the power of a multi-dimensional in vivo platform to expand our ability to predict the hazard potential of new compounds based on structural relatedness, ultimately leading to reliable toxicity predictions based on chemical structure.

A Literature Systematic Review with Meta-Analysis of Symptoms Prevalence in Covid-19: the Relevance of Olfactory Symptoms in Infection Not Requiring Hospitalization

PURPOSE OF REVIEW

To investigate the association between the olfactory dysfunction and the more typical symptoms (fever, cough, dyspnoea) within the Sars-CoV-2 infection (COVID-19) in hospitalized and non-hospitalized patients.

RECENT FINDINGS

PubMed, Scopus and Web of Science databases were reviewed from May 5, 2020, to June 1, 2020. Inclusion criteria included English, French, German, Spanish or Italian language studies containing original data related to COVID19, anosmia, fever, cough, and dyspnoea, in both hospital and non-hospital settings. Two investigators independently reviewed all manuscripts and performed quality assessment and quantitative meta-analysis using validated tools. A third author arbitrated full-text disagreements. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA), 11 of 135 studies fulfilled eligibility. Anosmia was estimated less prevalent than fever and cough (respectively rate difference = - 0.316, 95% CI: - 0.574 to - 0.058, Z = - 2.404, p < 0.016, k = 11 and rate difference = - 0.249, 95% CI: - 0.402 to - 0.096, Z = - 3.185, p < 0.001, k = 11); the analysis between anosmia and dyspnoea was not significant (rate difference = - 0.008, 95% CI: - 0.166 to 0.150, Z = - 0.099, p < 0.921, k = 8). The typical symptoms were significantly more frequent than anosmia in hospitalized more critical patients than in non-hospitalized ones (respectively [Q(1) = 50.638 p < 0.000, Q(1) = 52.520 p < 0.000, Q(1) = 100.734 p < 0.000).

SUMMARY

Patient with new onset olfactory dysfunction should be investigated for COVID-19. Anosmia is more frequent in non-hospitalized COVID-19 patients than in hospitalized ones.

Unraveling the Origin of Differentiable 'Turn-On' Fluorescence Sensing of Zn2+ and Cd2+ Ions with Squaramides

A squaramide ring conjugated with Schiff-bases decorated with hydroxy and methoxy functional groups differentially senses zinc and cadmium ions, which turn on the fluorescence. The feebly emitting free ligands light up in the presence of zinc and cadmium acetates, with the acetate ion playing a pivotal role as a conjugate anion. The selective and differentiable emission responses for zinc and cadmium ions make these ligands efficient multi-analyte sensing agents. Furthermore, these ligands could be used to differentially sense zinc and cadmium ions even in aqueous environments. The NMR investigations reveal marginal differences in the binding of zinc and cadmium ions to the ligands, whereas density functional theory calculations suggest the different extent of ligand-to-metal charge transfer (LMCT) contributes to the differential behavior. Finally, comparison of the excited-state dynamics of free ligand and the metal complexes reveal the appearance of longer lifetime (about 500-700 ps) component with complexation, due to rigidified molecular skeleton, thereby impeding the non-radiative processes.

High-content screening in zebrafish identifies perfluorooctanesulfonamide as a potent developmental toxicant

Per- and polyfluoroalkyl substances (PFASs) have been used for decades within industrial processes and consumer products, resulting in frequent detection within the environment. Using zebrafish embryos, we screened 38 PFASs for developmental toxicity and revealed that perfluorooctanesulfonamide (PFOSA) was the most potent developmental toxicant, resulting in elevated mortality and developmental abnormalities following exposure from 6 to 24 h post fertilization (hpf) and 6 to 72 hpf. PFOSA resulted in a concentration-dependent increase in mortality and abnormalities, with surviving embryos exhibiting a >12-h delay in development at 24 hpf. Exposures initiated at 0.75 hpf also resulted in a concentration-dependent delay in epiboly, although these effects were not driven by a specific sensitive window of development. We relied on mRNA-sequencing to identify the potential association of PFOSA-induced developmental delays with impacts on the embryonic transcriptome. Relative to stage-matched vehicle controls, these data revealed that pathways related to hepatotoxicity and lipid transport were disrupted in embryos exposed to PFOSA from 0.75 to 14 hpf and 0.75 to 24 hpf. Therefore, we measured liver area as well as neutral lipids in 128-hpf embryos exposed to vehicle (0.1% DMSO) or PFOSA from 0.75 to 24 hpf and clean water from 24 to 128 hpf, and showed that PFOSA exposure from 0.75 to 24 hpf resulted in a decrease in liver area and increase in yolk sac neutral lipids at 128 hpf. Overall, our findings show that early exposure to PFOSA adversely impacts embryogenesis, an effect that may lead to altered lipid transport and liver development.

Ciglitazone-a human PPARγ agonist-disrupts dorsoventral patterning in zebrafish

Peroxisome proliferator-activated receptor γ (PPARγ) is a ligand-activated transcription factor that regulates lipid/glucose homeostasis and adipocyte differentiation. While the role of PPARγ in adipogenesis and diabetes has been extensively studied, little is known about PPARγ function during early embryonic development. Within zebrafish, maternally-loaded pparγ transcripts are present within the first 6 h post-fertilization (hpf), and de novo transcription of zygotic pparγ commences at ~48 hpf. Since maternal pparγ transcripts are elevated during a critical window of cell fate specification, the objective of this study was to test the hypothesis that PPARγ regulates gastrulation and dorsoventral patterning during zebrafish embryogenesis. To accomplish this objective, we relied on (1) ciglitazone as a potent PPARγ agonist and (2) a splice-blocking, pparγ-specific morpholino to knockdown pparγ. We found that initiation of ciglitazone-a potent human PPARγ agonist-exposure by 4 hpf resulted in concentration-dependent effects on dorsoventral patterning in the absence of epiboly defects during gastrulation, leading to ventralized embryos by 24 hpf. Interestingly, ciglitazone-induced ventralization was reversed by co-exposure with dorsomorphin, a bone morphogenetic protein signaling inhibitor that induces strong dorsalization within zebrafish embryos. Moreover, mRNA-sequencing revealed that lipid- and cholesterol-related processes were affected by exposure to ciglitazone. However, pparγ knockdown did not block ciglitazone-induced ventralization, suggesting that PPARγ is not required for dorsoventral patterning nor involved in ciglitazone-induced toxicity within zebrafish embryos. Our findings point to a novel, PPARγ-independent mechanism of action and phenotype following ciglitazone exposure during early embryonic development.

Niclosamide Induces Epiboly Delay During Early Zebrafish Embryogenesis

Niclosamide is an antihelminthic drug used worldwide for the treatment of tapeworm infections. Recent drug repurposing screens have revealed that niclosamide exhibits diverse mechanisms of action and, as a result, demonstrates promise for a number of applications, including the treatment of cancer, bacterial infections, and Zika virus. As new applications of niclosamide will require non-oral delivery routes that may lead to exposure in utero, the objective of this study was to investigate the mechanism of niclosamide toxicity during early stages of embryonic development. Using zebrafish as a model, we found that niclosamide induced a concentration-dependent delay in epiboly progression during late-blastula and early-gastrula, an effect that was dependent on exposure during the maternal-to-zygotic transition-a period characterized by degradation of maternally derived transcripts, zygotic genome activation, and initiation of cell motility. Moreover, we found that niclosamide did not affect embryonic oxygen consumption, suggesting that oxidative phosphorylation-a well-established target for niclosamide within intestinal parasites-may not play a role in niclosamide-induced epiboly delay. However, mRNA-sequencing revealed that niclosamide exposure during blastula and early-gastrula significantly impacted the timing of zygotic genome activation as well as the abundance of cytoskeleton- and cell cycle regulation-specific transcripts. In addition, we found that niclosamide inhibited tubulin polymerization in vitro, suggesting that niclosamide-induced delays in epiboly progression may, in part, be driven by disruption of microtubule formation and cell motility within the developing embryo.

Maternal-to-zygotic transition as a potential target for niclosamide during early embryogenesis

Niclosamide is an antihelminthic drug used worldwide for the treatment of tapeworm infections. Recent drug repurposing screens have highlighted the broad bioactivity of niclosamide across diverse mechanisms of action. As a result, niclosamide is being evaluated for a range of alternative drug-repurposing applications, including the treatment of cancer, bacterial infections, and Zika virus. As new applications of niclosamide will require non-oral delivery routes that may lead to exposure in utero, it is important to understand the mechanism of niclosamide toxicity during early stages of embryonic development. Previously, we showed that niclosamide induces a concentration-dependent delay in epiboly progression in the absence of effects on oxidative phosphorylation - a well-established target for niclosamide. Therefore, the overall objective of this study was to further examine the mechanism of niclosamide-induced epiboly delay during zebrafish embryogenesis. Based on this study, we found that (1) niclosamide exposure during early zebrafish embryogenesis resulted in a decrease in yolk sac integrity with a concomitant decrease in the presence of yolk sac actin networks and increase in cell size; (2) within whole embryos, niclosamide exposure did not alter non-polar metabolites and lipids, but significantly altered amino acids specific to aminoacyl-tRNA biosynthesis; (3) niclosamide significantly altered transcripts related to translation, transcription, and mRNA processing pathways; and (4) niclosamide did not significantly alter levels of rRNA and tRNA. Overall, our findings suggest that niclosamide may be causing a systemic delay in embryonic development by disrupting the translation of maternally-supplied mRNAs, an effect that may be mediated through disruption of aminoacyl-tRNA biosynthesis.

Complex Interplay Among Nuclear Receptor Ligands, Cytosine Methylation, and the Metabolome in Driving Tris(1,3-dichloro-2-propyl)phosphate-Induced Epiboly Defects in Zebrafish

Tris(1,3-dichloro-2-propyl)phosphate (TDCIPP) is a high-production-volume organophosphate flame retardant (OPFR) that induces epiboly defects during zebrafish embryogenesis, leading to the disruption of dorsoventral patterning. Therefore, the objectives of this study were to (1) identify the potential mechanisms involved in TDCIPP-induced epiboly defects and (2) determine whether coexposure to triphenyl phosphate (TPHP)-an OPFR commonly detected with TDCIPP-enhances or mitigates epiboly defects. Although TDCIPP-induced epiboly defects were not associated with adverse impacts on cytoskeletal protein abundance in situ, the coexposure of embryos to TPHP partially blocked TDCIPP-induced epiboly defects. As nuclear receptors are targets for both TPHP and TDCIPP, we exposed the embryos to TDCIPP in the presence or absence of 69 nuclear receptor ligands and, similar to TPHP, found that ciglitazone (a peroxisome proliferator-activated receptor γ agonist) and 17β-estradiol (E2; an estrogen receptor α agonist) nearly abolished TDCIPP-induced epiboly defects. Moreover, E2 and ciglitazone mitigated TDCIPP-induced effects on CpG hypomethylation within the target loci prior to epiboly, and ciglitazone altered TDCIPP-induced effects on the abundance of two polar metabolites (acetylcarnitine and cytidine-5-diphosphocholine) during epiboly. Overall, our results point to a complex interplay among nuclear receptor ligands, cytosine methylation, and the metabolome in both the induction and mitigation of epiboly defects induced by TDCIPP.

Granular dot-like staining with MLH1 immunohistochemistry is a clone-dependent artefact

Immunohistochemistry (IHC) for DNA mismatch repair proteins MLH1, PMS2, MSH2, and MSH6 is used for microsatellite instability (MSI) screening in colorectal carcinoma (CRC) and endometrial carcinoma (EC). Loss of PMS2, with retained MLH1 staining occurs in germline mutations of PMS2 gene, and is an indication for genetic testing. We report a pitfall of immunohistochemical interpretation in an EC, initially regarded as MLH1-positive and PMS2-negative. Review of the MLH1-IHC (M1-clone) revealed a granular, dot-like, nuclear staining. On repeating the MLH1-IHC with a different clone (ES05-clone), complete negativity was noted, and on molecular testing, MLH1 promotor methylation was detected. The dot-like pattern was therefore adjudged a clone-dependent artefact. On reviewing the archived MLH1-IHC slides, we observed the same dot-like pattern in two CRCs; in both cases the M1-clone had been used. Awareness of this artefact may prevent reporting errors, and unnecessary referrals for germline mutation testing.

Maternal-to-zygotic transition as a potential target for niclosamide during early embryogenesis

Niclosamide is an antihelminthic drug used worldwide for the treatment of tapeworm infections. Recent drug repurposing screens have highlighted the broad bioactivity of niclosamide across diverse mechanisms of action. As a result, niclosamide is being evaluated for a range of alternative drug-repurposing applications, including the treatment of cancer, bacterial infections, and Zika virus. As new applications of niclosamide will require non-oral delivery routes that may lead to exposure in utero, it is important to understand the mechanism of niclosamide toxicity during early stages of embryonic development. Previously, we showed that niclosamide induces a concentration-dependent delay in epiboly progression in the absence of effects on oxidative phosphorylation - a well-established target for niclosamide. Therefore, the overall objective of this study was to further examine the mechanism of niclosamide-induced epiboly delay during zebrafish embryogenesis. Based on this study, we found that (1) niclosamide exposure during early zebrafish embryogenesis resulted in a decrease in yolk sac integrity with a concomitant decrease in the presence of yolk sac actin networks and increase in cell size; (2) within whole embryos, niclosamide exposure did not alter non-polar metabolites and lipids, but significantly altered amino acids specific to aminoacyl-tRNA biosynthesis; (3) niclosamide significantly altered transcripts related to translation, transcription, and mRNA processing pathways; and (4) niclosamide did not significantly alter levels of rRNA and tRNA. Overall, our findings suggest that niclosamide may be causing a systemic delay in embryonic development by disrupting the translation of maternally-supplied mRNAs, an effect that may be mediated through disruption of aminoacyl-tRNA biosynthesis.

mRNA-Sequencing Identifies Liver as a Potential Target Organ for Triphenyl Phosphate in Embryonic Zebrafish

Triphenyl phosphate (TPHP) is a commonly used organophosphate flame retardant and plasticizer in the United States. Using zebrafish as a model, the overall objective of this study was to identify potential organs that might be targeted by TPHP during embryonic development. Based on mRNA-sequencing, TPHP exposure from 24 to 30 h post fertilization (hpf) and 24 to 48 hpf significantly affected the abundance of 305 and 274 transcripts, respectively, relative to vehicle (0.1% DMSO) controls. In addition to minor effects on cardiotoxicity- and nephrotoxicity-related pathways, Ingenuity Pathway Analysis (IPA) of significantly affected transcripts within 30- and 48-hpf embryos revealed that hepatotoxicity-related pathways were strongly affected following exposure to TPHP alone. Moreover, while pre-treatment with fenretinide (a retinoic acid receptor agonist) mitigated TPHP-induced pericardial edema and liver enlargement at 72 hpf and 128 hpf, respectively, IPA revealed that fenretinide was unable to block TPHP-induced effects on cardiotoxicity-, nephrotoxicity-, and hepatotoxicity-related pathways at 48 hpf, suggesting that TPHP-induced effects on the transcriptome were not associated with toxicity later in development. In addition, based on Oil Red O staining, we found that exposure to TPHP nearly abolished neutral lipids from the embryonic head and trunk and, based on metabolomics, significantly decreased the total abundance of metabolites - including betaine, a known osmoprotectant - at 48 and 72 hpf. Overall, our data suggest that, in addition to the heart, TPHP exposure during early development results in adverse effects on the liver, lipid utilization, and osmoregulation within embryonic zebrafish.

Large debris dumps in the northern South China Sea

Knowledge of the abundance, source, and fate of marine debris in the deep sea is largely constrained thus far. Here, we report the existence of large deep-sea debris dumps that have not been reported before on the seafloor worldwide. Marine debris remarkably accumulated at ~1700-1800 m in the tributary submarine canyons of the Xisha Trough, northern South China Sea (SCS). Although marine debris in Xisha Trough is patchy, the debris abundance was as high as 36,818 and 51,929 items/km² at locations SY78 and SY82, respectively, which is one order of magnitude higher than that in other submarine canyons. We propose that most of the debris came from fishery and navigation activities, as indicated by the categories of debris collected from the seafloor dumps. Seasonal surface ocean currents of the SCS and geomorphology of submarine canyons possibly influence the movement of the debris from coasts to the deep seafloor.

Disruption of Nuclear Receptor Signaling Alters Triphenyl Phosphate-Induced Cardiotoxicity in Zebrafish Embryos

Triphenyl phosphate (TPHP) is an unsubstituted aryl phosphate ester used as a flame retardant and plasticizer within the United States. Using zebrafish as a model, the objectives of this study were to rely on (1) mRNA-sequencing to uncover pathways disrupted following embryonic TPHP exposure and (2) high-content screening to identify nuclear receptor ligands that enhance or mitigate TPHP-induced cardiotoxicity. Based on mRNA-sequencing, TPHP exposure from 24 to 72-h postfertilization (hpf) resulted in a concentration-dependent increase in the number of transcripts significantly affected at 72 hpf, and pathway analysis revealed that 5 out of 9 nuclear receptor pathways were associated with the retinoid X receptor (RXR). Based on a screen of 74 unique nuclear receptor ligands as well as follow-up experiments, 2 compounds-ciglitazone (a peroxisome proliferator-activated receptor gamma, or PPARγ, agonist) and fenretinide (a pan-retinoic acid receptor, or RAR, agonist)-reliably mitigated TPHP-induced cardiotoxicity in the absence of effects on TPHP uptake or metabolism. As these data suggested that TPHP may be activating RXR (a heterodimer for both RARs and PPARγ), we coexposed embryos to HX 531-a pan-RXR antagonist-from 24 to 72 hpf and, contrary to our hypothesis, found that coexposure to HX 531 significantly enhanced TPHP-induced cardiotoxicity. Using a luciferase reporter assay, we also found that TPHP did not activate nor inhibit chimeric human RXRα, RXRβ, or RXRγ, suggesting that TPHP does not directly bind nor interact with RXRs. Overall, our data suggest that TPHP may interfere with RXR-dependent pathways involved in cardiac development.

Diphenyl Phosphate-Induced Toxicity During Embryonic Development

Diphenyl phosphate (DPHP) is an aryl phosphate ester (APE) used as an industrial catalyst and chemical additive and is the primary metabolite of flame retardant APEs, including triphenyl phosphate (TPHP). Minimal DPHP-specific toxicity studies have been published despite ubiquitous exposure within human populations following metabolism of TPHP and other APEs. Therefore, the objective of this study was to determine the potential for DPHP-induced toxicity during embryonic development. Using zebrafish as a model, we found that DPHP significantly increased the distance between the sinus venosus and bulbus arteriosis (SV-BA) at 72 h postfertilization (hpf) following initiation of exposure before and after cardiac looping. Interestingly, pretreatment with d-mannitol mitigated DPHP-induced effects on SV-BA length despite the absence of DPHP effects on pericardial area, suggesting that DPHP-induced cardiac defects are independent of pericardial edema formation. Using mRNA-sequencing, we found that DPHP disrupts pathways related to mitochondrial function and heme biosynthesis; indeed, DPHP significantly decreased hemoglobin levels in situ at 72 hpf following exposure from 24 to 72 hpf. Overall, our findings suggest that, similar to TPHP, DPHP impacts cardiac development, albeit the potency of DPHP is significantly less than TPHP within developing zebrafish.

mRNA-miRNA-Seq Reveals Neuro-Cardio Mechanisms of Crude Oil Toxicity in Red Drum ( Sciaenops ocellatus)

Polycyclic aromatic hydrocarbons (PAHs) present in crude oil can cause global gene dysregulation and developmental impairment in fish. However, the mechanisms that alter gene regulation are not well understood. In this study, larval red drum ( Sciaenops ocellatus) were exposed to water accommodated fractions of source oil (6.8, 13.7, and 35.9 μg/L total PAHs) and weathered slick oil (4.7, 8.1, and 18.0 μg/L total PAHs) from the Deepwater Horizon (DWH) oil spill. The global mRNA-microRNA functional networks associated with the toxicity of DWH oil were explored by next-generation sequencing and in-depth bioinformatics analyses. Both source and slick oil significantly altered the expression of miR-18a, miR-27b, and miR-203a across all exposure concentrations. Consistent with the observed concentration-dependent morphological changes, the target mRNAs of these microRNAs were predominantly involved in neuro-cardio system development processes and associated key signaling pathways such as axonal guidance signaling, cAMP-response-element-binding protein signaling in neurons, calcium signaling, and nuclear-factor-of-activated T cells signaling in cardiac hypertrophy. The results indicated that the developmental toxicity of crude oil may result from the abnormal expression of microRNAs and associated target genes, especially for the nervous system. Moreover, we provide a case study for systematic toxicity evaluation leveraging mRNA-microRNA-seq data using nonmodel species.

Abstract P5-05-01: Metabolic enzyme PFKFB4 activates transcriptional coactivator SRC-3 to drive aggressive metastatic breast cancer

Background: Metabolic rewiring is one of the central hallmarks of cancer progression and survival to support anabolic and energetic demands. Tumor cells constantly alter their metabolic state in response to oncogenic stimuli, nutrient availability, and interaction with immune cells however the precise regulation that precedes the metabolic alteration is poorly understood. Here we report a direct interaction of glycolytic enzyme PFKFB4 with transcriptional coregulator SRC-3. PFKFB4 functions as a critical regulator of Warburg effect and our study reveals that upon glucose stimulation PFKFB4 activates SRC-3 driving an invasive-metastatic breast cancer.

Methods: Molecular experiments were performed to understand the transcriptional activation of SRC-3 by PFKFB4 enzyme. Chromatin immunoprecipitation and gene expression studies were performed to investigate the functions of PFKFB4/SRC-3 crosstalk on transcriptional regulation. Metabolomics and isotope tracing studies were performed to identify the metabolic adaptations regulated by PFKFB4/SRC-3 in breast tumors. PFKFB4-knockout was established using CRISPR-Cas9 system and functional studies were carried out to define its role in tumor cell proliferation, invasion-migration, and breast to lung metastasis. Human breast tumor samples were evaluated to identify the clinical importance of PFKFB4/SRC-3 crosstalk in patients.

Results:Molecular studies revealed that PFKFB4 enzyme phosphorylates SRC-3 at serine 857 (S857) enhancing its transcriptional activity, whereas either suppression of PFKFB4 or ectopic expression of a phosphorylation-deficient SRC-3 mutant S857A (SRC-3S857A) significantly abolished SRC-3-mediated transcriptional output (p&lt;0.000001). Functionally, PFKFB4-driven SRC-3 activation drives glucose flux towards the pentose phosphate pathway enabling purine synthesis by transcriptionally upregulating the expression of enzyme transketolase (TKT). Deletion of PFKFB4 by CRISPR-Cas9 system resulted in significantly reduced proliferation (p&lt;0.05) and migration-invasion (p&lt;0.001) compared to wildtype breast tumor cells. Ablation of SRC-3 or PFKFB4 suppressed in vivo breast tumor growth and prevents metastasis to the lung from an orthotopic setting (p&lt;0.0001). PFKFB4 and phosphorylated SRC-3 levels are significantly increased in breast tumors (p=0.02), whereas, in patients with the basal subtype, PFKFB4 and SRC-3 drive a common protein signature that correlates with the poor survival of TNBC patients (p=0.03).

Conclusion:Our data suggest that the Warburg pathway enzyme PFKFB4 acts as a molecular fulcrum that couples sugar metabolism to transcriptional activation by stimulating SRC-3 to promote aggressive metastatic tumors. It also provides first evidence how Warburg pathway drives aggressive breast tumorigenesis by directly activating powerful oncogene SRC-3. Our work suggests that targeting the PFKFB4–SRC-3 axis may be therapeutically valuable in breast tumors that are notably dependent on glucose metabolism.

(This work is funded by grants from Susan G. Komen and NCI to S.D.)

Citation Format: Dasgupta S, Anand V, John H, Sawant Dessai A, Katsuta E, Takabe K, O'Malley B. Metabolic enzyme PFKFB4 activates transcriptional coactivator SRC-3 to drive aggressive metastatic breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P5-05-01.

Evaluation of the estrogen receptor alpha as a possible target of bifenthrin effects in the estrogenic and dopaminergic signaling pathways in zebrafish embryos

Bifenthrin (BF) is a pyrethroid insecticide widely used in urban and agricultural applications. Previous studies in embryos of zebrafish have shown that BF can affect estradiol biosynthesis and the dopaminergic system. To examine the role of the estrogen receptor (ER) in the endocrine effects of BF, embryos were exposed for 96 h to a mixture of 0.15 and 1.5 μg/L BF and an ER agonist (17α-ethynylestradiol - EE2) at 0.09 μg/L. Transcripts related to estrogenic (vitellogenin VTG) and dopaminergic (tyrosine hydroxylase (TH), dopamine receptor 1 (DR1), monoamine oxidase (MAO), and catechol-O-methyltransferase b (COMTb)) signaling pathways were investigated by qRT-PCR. Dopamine (DA) and its metabolites (homovanillic acid (HVA) and 3,4-dihydroxyphenylacetic acid (DOPAC)) were also measured. There was a significant increase in VTG, DR1, MAO and COMTb mRNA levels and HVA-DA ratios within all zebrafish embryos exposed to EE2, including EE2 alone, 0.15 μg/L BF + EE2 and 1.5 μg/L BF + EE2. A significant decrease in homogenate concentrations of DA was observed within all zebrafish embryos exposed to EE2, which included EE2 alone, 0.15 μg/L BF + EE2 and 1.5 μg/L BF + EE2. Co-exposure of BF with EE2 failed to diminish estrogenic or dopaminergic signaling in embryos. Additionally, embryos with diminished ERα expression by morpholino injection were exposed to 0.15 μg/L BF, 1.5 μg/L BF and 0.09 μg/L EE2, with subsequent gene expression measurements. ERα knockdown did not prevent the effects of BF, indicating ERα may have a limited role in the estrogenic and dopaminergic effects caused by BF in zebrafish embryos.

Abstract P2-02-04: CD73 expression regulated by estrogen signaling associates with poor prognosis in estrogen receptor (ER)-positive breast cancer

Introduction: CD73, a cell surface enzyme, catalyzes the generation of adenosine from ATP and ADP in the tumor microenvironment along with CD39. Accumulated extracellular adenosine functions as immune-suppressor, and also binds to adenosine receptors which promotes angiogenesis and cell proliferation that results in accelerate cancer progression. However, the clinical significance and molecular function of CD73 expression in breast cancer remains unclear.

Methods: Utilizing publicly available breast cancer cohorts of The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO), clinical significance as well as underlying mechanisms were investigated. Molecular experiments were carried out in MCF7 cells, ER-positive breast cancer cell line, to investigate the role of estrogen signaling on CD73/CD39 expression.

Results: In treatment naïve TCGA cohort, CD73 expression level was significantly lower in ER-positive breast cancers compared to ER-negative tumors. Higher CD73 expression was associated with worse overall survival in whole cohort (p=0.021) and ER-positive tumors (p=0.003), but not in ER-negative tumors. Gene Set Enrichment Analysis revealed that estrogen response gene sets (Early; NES=-1.57, p=0.043, Late; NES=-1.61, p=0.021) were significantly enriched in CD73 low expressing ER-positive tumors, suggesting estrogen signaling may repress CD73 expression. To test this hypothesis, we analyzed the expression of CD73 and CD39 in MCF7 cells treated with estrogen, tamoxifen or both. Our data revealed that estrogen treatment suppressed CD73 and CD39 expression, whereas tamoxifen treatment enhanced expression of the genes. These findings suggest that CD73 and CD39 gene expression is suppressed by estrogen signaling, whereas binding of ER antagonists such as tamoxifen can remove the repressive effect on gene expression. On the other hand, epithelial-mesenchymal transition (EMT) (Normalized Enrichment Score; NES=2.41, p&lt;0.001) and angiogenesis (NES=2.33, p&lt;0.001) gene sets were significantly enriched in CD73 high expressing ER-positive tumors. CIBERSORT, which is an algorithm to estimate infiltrating immune cells by gene expression, demonstrated that CD73 high expressing ER-positive tumors have less infiltrating CD8-positive T cells, memory B cells and plasma cells, implying that CD73 high expressing tumors have immune suppressive environment, which is in agreement with the notion that CD73 high tumors are immunosuppressive. Finally, we found that CD73 expression was significantly elevated post-chemotherapy compared to tumors prior to the treatment (p=0.007), and CD73 high expression patients showed worse relapse-free survival in neoadjuvant chemotherapy patients cohort (p=0.003).

Conclusion: Molecular studies revealed that CD73 expression is regulated by estrogen signaling. Increased expression of CD73 significantly correlates with worse outcomes in ER-positive breast cancer patients. This may be due to upregulated pro-metastatic gene signatures such as EMT and angiogenesis as well as less infiltration of anti-cancer immune cells by adenosine generated by CD73 in the tumor microenvironment. Our data reveals an intriguing mechanism which may be responsible for recurrence and metastasis of ER-positive breast cancer.

Citation Format: Katsuta E, Anand V, Yan L, Dasgupta S, Takabe K. CD73 expression regulated by estrogen signaling associates with poor prognosis in estrogen receptor (ER)-positive breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P2-02-04.

Homogeneous reduced moment in a gapful scalar chiral kagome antiferromagnet

We present a quantitative experimental investigation of the scalar chiral magnetic order with in Nd3Sb3Mg2O14. Static magnetization reveals a net ferromagnetic ground state, and inelastic neutron scattering from the hyperfine coupled nuclear spin reveals a local ordered moment of 1.76(6) μ B , just 61(2)% of the saturated moment size. The experiments exclude static disorder as the source of the reduced moment. A 38(1) μ eV gap in the magnetic excitation spectrum inferred from heat capacity rules out thermal fluctuations and suggests a multipolar explanation for the moment reduction. We compare Nd3Sb3Mg2O14 to Nd pyrochlores and show that Nd2Zr2O7 is in a spin fragmented state using nuclear Schottky heat capacity.

Tris(1,3-dichloro-2-propyl) Phosphate Exposure During the Early-Blastula Stage Alters the Normal Trajectory of Zebrafish Embryogenesis

Tris(1,3-dichloro-2-propyl) phosphate (TDCIPP) is an organophosphate flame retardant used around the world. Within zebrafish, we previously showed that initiation of TDCIPP exposure during cleavage (0.75 h post-fertilization, hpf) results in epiboly disruption at 6 hpf, leading to dorsalized embryos by 24 hpf, a phenotype that mimics the effects of dorsomorphin (DMP), a bone morphogenetic protein (BMP) antagonist that dorsalizes embryos in the absence of epiboly defects. The objective of this study was to (1) investigate the role of BMP signaling in TDCIPP-induced toxicity during early embryogenesis, (2) identify other pathways and processes targeted by TDCIPP, and (3) characterize the downstream impacts of early developmental defects. Using zebrafish as a model, we first identified a sensitive window for TDCIPP-induced effects following exposure initiation at 0.75 hpf. We then investigated the effects of TDCIPP on the transcriptome during the first 24 h of development using mRNA sequencing and amplicon sequencing. Finally, we relied on whole-mount immunohistochemistry, dye-based labeling, and morphological assessments to study abnormalities later in embryonic development. Overall, our data suggest that the initiation of TDCIPP exposure during early blastula alters the normal trajectory of early embryogenesis by inducing gastrulation defects and aberrant germ-layer formation, leading to abnormal tissue and organ development within the embryo.

Transpectoral Anterior Approach to the Axilla for Lymph Node Dissection in Association with Mastectomy Preserving Both Pectoral Muscles and Their Neurovascular Bundles

In Patey's mastectomy, which is still the most common operation for breast cancer, axillary node dissection (AND) is performed through the base of the axilla after retracting the pectoralis major muscle and excising the pectoralis minor muscle (some surgeons preserve the latter). This has the disadvantage of inadequate exposure of the axilla and the risk of damage to the neurovascular bundles supplying the pectoral muscles, which in the long run may lead to atrophy of these muscles. A transpectoral anterior approach to the axilla for AND in association with mastectomy was attempted in 115 cases to obviate the above-mentioned disadvantages. The approach included: 1) splitting of the pectoralis major between the clavicular and sternal fibers; 2) mobilization and swinging of the pectoralis minor into different directions by means of a sling to facilitate AND at selected levels. The major advantages of this approach were: 1) total preservation of both pectoral muscles with their neurovascular bundles maintained the normal anatomy and function of the shoulder; 2) the axilla was directly approached through the anterior wall instead of through the base; in this way the axillary contents were exposed almost at surface level; 3) the dissection plane could be limited to anterior to and below the axillary vein and the risk of postoperative lymphedema could thus be minimized; 4) change of position of the ipsilateral arm was not necessary; 5) the duration of surgery was reduced. Monoblock ablation of significant and suspected tissues, maintaining the normal anatomy and function of the shoulder, could be easily accomplished with this approach.