The relationship between the use of electronic nicotine delivery systems (ENDS) and effects on pulmonary immune responses-a literature review.

INTRODUCTION: The use of electronic nicotine delivery systems (ENDS), or vaping, is a relatively recent phenomenon, and there are various gaps in our current knowledge regarding the specific effects of e-cigarettes, such as their immunological effects. The importance of this question became even more relevant in light of the COVID-19 pandemic. OBJECTIVE: This literature review examines the relationship between the use of electronic nicotine delivery systems (ENDS) and immunological effects to examine available information and identify gaps in the current knowledge. Our search strategy included studies focusing on the effects of ENDS on the immune response during infectious respiratory diseases such as COVID-19 and pneumonia. METHODS: Peer-reviewed studies presenting quantitative data published from 2007, the year that e-cigarettes were introduced to the US market until 2022 have been included. All studies were indexed in PubMed. We excluded papers on THC and EVALI (E-cigarette, or Vaping Product, Use Associated Lung Injury) as we wanted to focus on the effects of nicotine devices. RESULTS: Among the 21 articles that assessed the relationship between ENDS and immunological health effects, we found eight studies based on cell models, two articles based on both cell and mouse models, five articles based on mouse models, and six studies of human populations. Most of the articles identified in our review demonstrated a potential association between vaping and adverse immunological health effects. DISCUSSION: Overall, the evidence from the cell and animal studies indicates that there is a positive, statistically significant association between vaping and adverse immune response during infectious respiratory diseases. The evidence from human studies is not conclusive.

Exposure to arsenic at different life-stages and DNA methylation meta-analysis in buccal cells and leukocytes.

BACKGROUND: Arsenic (As) exposure through drinking water is a global public health concern. Epigenetic dysregulation including changes in DNA methylation (DNAm), may be involved in arsenic toxicity. Epigenome-wide association studies (EWAS) of arsenic exposure have been restricted to single populations and comparison across EWAS has been limited by methodological differences. Leveraging data from epidemiological studies conducted in Chile and Bangladesh, we use a harmonized data processing and analysis pipeline and meta-analysis to combine results from four EWAS. METHODS: DNAm was measured among adults in Chile with and without prenatal and early-life As exposure in PBMCs and buccal cells (N = 40, 850K array) and among men in Bangladesh with high and low As exposure in PBMCs (N = 32, 850K array; N = 48, 450K array). Linear models were used to identify differentially methylated positions (DMPs) and differentially variable positions (DVPs) adjusting for age, smoking, cell type, and sex in the Chile cohort. Probes common across EWAS were meta-analyzed using METAL, and differentially methylated and variable regions (DMRs and DVRs, respectively) were identified using comb-p. KEGG pathway analysis was used to understand biological functions of DMPs and DVPs. RESULTS: In a meta-analysis restricted to PBMCs, we identified one DMP and 23 DVPs associated with arsenic exposure; including buccal cells, we identified 3 DMPs and 19 DVPs (FDR < 0.05). Using meta-analyzed results, we identified 11 DMRs and 11 DVRs in PBMC samples, and 16 DMRs and 19 DVRs in PBMC and buccal cell samples. One region annotated to LRRC27 was identified as a DMR and DVR. Arsenic-associated KEGG pathways included lysosome, autophagy, and mTOR signaling, AMPK signaling, and one carbon pool by folate. CONCLUSIONS: Using a two-step process of (1) harmonized data processing and analysis and (2) meta-analysis, we leverage four DNAm datasets from two continents of individuals exposed to high levels of As prenatally and during adulthood to identify DMPs and DVPs associated with arsenic exposure. Our approach suggests that standardizing analytical pipelines can aid in identifying biological meaningful signals.

Metabolomics in Preclinical Drug Safety Assessment: Current Status and Future Trends.

Metabolomics is emerging as a powerful systems biology approach for improving preclinical drug safety assessment. This review discusses current applications and future trends of metabolomics in toxicology and drug development. Metabolomics can elucidate adverse outcome pathways by detecting endogenous biochemical alterations underlying toxicity mechanisms. Furthermore, metabolomics enables better characterization of human environmental exposures and their influence on disease pathogenesis. Metabolomics approaches are being increasingly incorporated into toxicology studies and safety pharmacology evaluations to gain mechanistic insights and identify early biomarkers of toxicity. However, realizing the full potential of metabolomics in regulatory decision making requires a robust demonstration of reliability through quality assurance practices, reference materials, and interlaboratory studies. Overall, metabolomics shows great promise in strengthening the mechanistic understanding of toxicity, enhancing routine safety screening, and transforming exposure and risk assessment paradigms. Integration of metabolomics with computational, in vitro, and personalized medicine innovations will shape future applications in predictive toxicology.

The Implementation Moonshot Project for Alternative Chemical Testing (IMPACT) toward a Human Exposome Project.

The Human Exposome Project aims to revolutionize our understanding of how environmental exposures affect human health by systematically cataloging and analyzing the myriad exposures individuals encounter throughout their lives. This initiative draws a parallel with the Human Genome Project, expanding the focus from genetic factors to the dynamic and complex nature of environ-mental interactions. The project leverages advanced methodologies such as omics technologies, biomonitoring, microphysiological systems (MPS), and artificial intelligence (AI), forming the foun-dation of exposome intelligence (EI) to integrate and interpret vast datasets. Key objectives include identifying exposure-disease links, prioritizing hazardous chemicals, enhancing public health and regulatory policies, and reducing reliance on animal testing. The Implementation Moonshot Project for Alternative Chemical Testing (IMPACT), spearheaded by the Center for Alternatives to Animal Testing (CAAT), is a new element in this endeavor, driving the creation of a public-private part-nership toward a Human Exposome Project with a stakeholder forum in 2025. Establishing robust infrastructure, fostering interdisciplinary collaborations, and ensuring quality assurance through sys-tematic reviews and evidence-based frameworks are crucial for the project's success. The expected outcomes promise transformative advancements in precision public health, disease prevention, and a more ethical approach to toxicology. This paper outlines the strategic imperatives, challenges, and opportunities that lie ahead, calling on stakeholders to support and participate in this landmark initiative for a healthier, more sustainable future.

This paper outlines a proposal for a "Human Exposome Project" to comprehensively study how environmental exposures affect human health throughout our lives. The exposome refers to all the environmental factors we are exposed to, from chemicals to diet to stress. The project aims to use advanced technologies like artificial intelligence, lab-grown mini-organs, and detailed biological measurements to map how different exposures impact our health. This could help identify causes of diseases and guide better prevention strategies. Key goals include finding links between spe­cific exposures and health problems, determining which chemicals are most concerning, improving public health policies, and reducing animal testing. The project requires collaboration between researchers, government agencies, companies, and others. While ambitious, this effort could revo­lutionize our understanding of environmental health risks. The potential benefits for improving health and preventing disease make this an important endeavor to a precise and comprehensive approach to public health and disease prevention.

Transcriptomic Effects of Low-Dose Inorganic Arsenic Exposure on Murine Bone Marrow-Derived Macrophages.

Both tissue-resident macrophages and monocytes recruited from the bone marrow that transform into tissue-resident cells play critical roles in mediating homeostasis as well as in the pathology of inflammatory diseases. Inorganic arsenic (iAs) is the most common drinking water contaminant worldwide and represents a major public health concern. Several diseases that macrophages have implicated involvement in are caused by iAs exposure, including cardiovascular disease, cancer, and increased risk of infectious disease. Therefore, understanding the effects of iAs exposure on macrophages can help us better grasp the full range of arsenic immunotoxicity and better design therapeutic targets for iAs-induced diseases particularly in exposed populations. In this study, we analyzed the transcriptome of low dose iAs-exposed male and female murine bone marrow-derived macrophages (BMDMs) with either M0, M1, or M2 stimulation. We identified differentially expressed genes by iAs in a sex- and stimulation-dependent manner and used bioinformatics tools to predict protein-protein interactions, transcriptional regulatory networks, and associated biological processes. Overall, our data suggest that M1-stimulated, especially female-derived, BMDMs are most susceptible to iAs exposure. Most notably, we observed significant downregulation of major proinflammatory transcription factors, like IRF8, and its downstream targets, as well as genes encoding proteins involved in pattern recognition and antigen presentation, such as TLR7, TLR8, and H2-D1, potentially providing causal insight regarding arsenic's role in perturbing immune responses to infectious diseases. We also observed significant downregulation of genes involved in processes crucial to coordinating a proinflammatory response including leukocyte migration, differentiation, and cytokine and chemokine production and response. Finally, we discovered that 24 X-linked genes were dysregulated in iAs-exposed female stimulation groups compared to only 3 across the iAs-exposed male stimulation groups. These findings elucidate the potential mechanisms underlying the sex-differential iAs-associated immune-related disease risk.

Subchronic exposure to ambient PM 2.5 impairs novelty recognition and spatial memory.

Air pollution remains a great challenge for public health, with the detrimental effects of air pollution on cardiovascular, rhinosinusitis, and pulmonary health increasingly well understood. Recent epidemiological associations point to the adverse effects of air pollution on cognitive decline and neurodegenerative diseases. Mouse models of subchronic exposure to PM 2.5 (ambient air particulate matter < 2.5 µm) provide an opportunity to demonstrate the causality of target diseases. Here, we subchronically exposed mice to concentrated ambient PM 2.5 for 7 weeks (5 days/week; 8h/day) and assessed its effect on behavior using standard tests measuring cognition or anxiety-like behaviors. Average daily PM 2.5 concentration was 200 µg/m 3 in the PM 2.5 group and 10 µg/m 3 in the filtered air group. The novel object recognition (NOR) test was used to assess the effect of PM 2.5 exposure on recognition memory. The increase in exploration time for a novel object versus a familiarized object was lower for PM 2.5 -exposed mice (42% increase) compared to the filtered air (FA) control group (110% increase). In addition, the calculated discrimination index for novel object recognition was significantly higher in FA mice (67 %) compared to PM 2.5 exposed mice (57.3%). The object location test (OLT) was used to examine the effect of PM 2.5 exposure on spatial memory. In contrast to the FA-exposed control mice, the PM 2.5 exposed mice exhibited no significant increase in their exploration time between novel location versus familiarized location indicating their deficit in spatial memory. Furthermore, the discrimination index for novel location was significantly higher in FA mice (62.6%) compared to PM 2.5 exposed mice (51%). Overall, our results demonstrate that subchronic exposure to higher levels of PM 2.5 in mice causes impairment of novelty recognition and spatial memory.

Prenatal Exposure to Toxic Metals and Neural Tube Defects: A Systematic Review of the Epidemiologic Evidence.

BACKGROUND: Neural tube defects (NTDs) affect >300,000 pregnancies worldwide annually. Few nongenetic factors, other than folate deficiency, have been identified that may provide intervenable solutions to reduce the burden of NTDs. Prenatal exposure to toxic metals [arsenic (As), cadmium (Cd), mercury (Hg), manganese (Mn) and lead (Pb)] may increase the risk of NTDs. Although a growing epidemiologic literature has examined associations, to our knowledge no systematic review has been conducted to date. OBJECTIVE: Through adaptation of the Navigation Guide systematic review methodology, we aimed to answer the question "does exposure to As, Cd, Hg, Mn, or Pb during gestation increase the risk of NTDs?" and to assess challenges to evaluating this question given the current evidence. METHODS: We selected available evidence on prenatal As, Cd, Hg, Mn, or Pb exposure and risk of specific NTDs (e.g., spina bifida, anencephaly) or all NTDs via a comprehensive search across MEDLINE, Embase, Web of Science, and TOXLINE databases and applied inclusion/exclusion criteria. We rated the quality and strength of the evidence for each metal. We applied a customized risk of bias protocol and evaluated the sufficiency of evidence of an effect of each metal on NTDs. RESULTS: We identified 30 studies that met our criteria. Risk of bias for confounding and selection was high in most studies, but low for missing data. We determined that, although the evidence was limited, the literature supported an association between prenatal exposure to Hg or Mn and increased risk of NTDs. For the remaining metals, the evidence was inadequate to establish or rule out an effect. CONCLUSION: The role of gestational As, Cd, or Pb exposure in the etiology of NTDs remains unclear and warrants further investigation in high-quality studies, with a particular focus on controlling confounding, mitigating selection bias, and improving exposure assessment. https://doi.org/10.1289/EHP11872.

Long-term effects of prenatal arsenic exposure from gestational day 9 to birth on lung, heart, and immune outcomes in the C57BL/6 mouse model.

Prenatal arsenic exposure is a major public health concern, associated with altered birth outcomes and increased respiratory disease risk. However, characterization of the long-term effects of mid-pregnancy (second trimester) arsenic exposure on multiple organ systems is scant. This study aimed to characterize the long-term impact of mid-pregnancy inorganic arsenic exposure on the lung, heart, and immune system, including infectious disease response using the C57BL/6 mouse model. Mice were exposed from gestational day 9 till birth to either 0 or 1000 µg/L sodium (meta)arsenite in drinking water. Male and female offspring assessed at adulthood (10-12 weeks of age) did not show significant effects on recovery outcomes after ischemia reperfusion injury but did exhibit increased airway hyperresponsiveness compared to controls. Flow cytometric analysis revealed significantly greater total numbers of cells in arsenic-exposed lungs, lower MHCII expression in natural killer cells, and increased percentages of dendritic cell populations. Activated interstitial (IMs) and alveolar macrophages (AMs) isolated from arsenic-exposed male mice produced significantly less IFN-γ than controls. Conversely, activated AMs from arsenic-exposed females produced significantly more IFN-γ than controls. Although systemic cytokine levels were higher upon Mycobacterium tuberculosis (Mtb) infection in prenatally arsenic-exposed offspring there was no difference in lung Mtb burden compared to controls. This study highlights significant long-term impacts of prenatal arsenic exposure on lung and immune cell function. These effects may contribute to the elevated risk of respiratory diseases associated with prenatal arsenic exposure in epidemiology studies and point to the need for more research into mechanisms driving these maintained responses.

First Organoid Intelligence (OI) workshop to form an OI community.

The brain is arguably the most powerful computation system known. It is extremely efficient in processing large amounts of information and can discern signals from noise, adapt, and filter faulty information all while running on only 20 watts of power. The human brain's processing efficiency, progressive learning, and plasticity are unmatched by any computer system. Recent advances in stem cell technology have elevated the field of cell culture to higher levels of complexity, such as the development of three-dimensional (3D) brain organoids that recapitulate human brain functionality better than traditional monolayer cell systems. Organoid Intelligence (OI) aims to harness the innate biological capabilities of brain organoids for biocomputing and synthetic intelligence by interfacing them with computer technology. With the latest strides in stem cell technology, bioengineering, and machine learning, we can explore the ability of brain organoids to compute, and store given information (input), execute a task (output), and study how this affects the structural and functional connections in the organoids themselves. Furthermore, understanding how learning generates and changes patterns of connectivity in organoids can shed light on the early stages of cognition in the human brain. Investigating and understanding these concepts is an enormous, multidisciplinary endeavor that necessitates the engagement of both the scientific community and the public. Thus, on Feb 22-24 of 2022, the Johns Hopkins University held the first Organoid Intelligence Workshop to form an OI Community and to lay out the groundwork for the establishment of OI as a new scientific discipline. The potential of OI to revolutionize computing, neurological research, and drug development was discussed, along with a vision and roadmap for its development over the coming decade.

A meta-analysis of genome-wide association studies of follicular lymphoma.

BACKGROUND: B-cell non-Hodgkin lymphoma represents a diverse group of hematological malignancies, of which follicular lymphoma (FL) is one of the most common subtypes. Family and epidemiological studies suggest an important genetic role in the etiology of FL. In recent genome-wide association studies (GWAS) of FL, several genetic susceptibility loci have been identified on chromosome 6p21.33 (rs6457327) and 6p21.32 (rs10484561, rs2647012) in the human leukocyte antigen class I and class II regions. To identify new genetic variants and further elucidate the genetic basis of FL, a meta-analysis was performed of the top 1000 SNPs associated with FL risk from two GWAS in the US, Denmark and Sweden (592 cases, 1541 controls), with independent validation in 107 cases and 681 controls. RESULTS: rs9275517 and rs3117222 in the HLA class II region were validated and inversely associated with FL risk (rs9275517: OR = 0.63, 95% CI = 0.55-0.73, p = 4.03 × 10(-11); rs3117222: OR = 0.66, 95% CI = 0.57-0.77, p = 1.45 × 10(-7)). rs9275517, which is in high linkage disequilibrium with rs2647012 (r2 = 0.9), was no longer associated with FL after conditioning on rs2647012. The rs3117222 association was independent of established FL SNPs, but not of the HLA-DPB1*0301 allele. Using publicly available gene expression profiles with matching genotype information, we found that rs3117222 also was significantly correlated with increased HLA-DPB1 expression. CONCLUSIONS: By performing a meta-analysis of two GWAS of FL, we further validated the relevance of HLA-DPB1*0301 as a protective allele in the pathogenesis of FL. Moreover, the protective rs3117222 A allele correlated with increased levels of HLA-DPB1, suggesting a possible disease mechanism involving HLA-DPB1 expression regulation. Our results add further support to the major role of HLA genetic variation in the pathogenesis of FL.

Common variants within 6p21.31 locus are associated with chronic lymphocytic leukaemia and, potentially, other non-Hodgkin lymphoma subtypes.

A recent meta-analysis of three genome-wide association studies of chronic lymphocytic leukaemia (CLL) identified two common variants at the 6p21.31 locus that are associated with CLL risk. To verify and further explore the association of these variants with other non-Hodgkin lymphoma (NHL) subtypes, we genotyped 1196 CLL cases, 1699 NHL cases, and 2410 controls. We found significant associations between the 6p21.31 variants and CLL risk (rs210134: P = 0·01; rs210142: P = 6·8 × 10(-3)). These variants also showed a trend towards association with some of the other NHL subtypes. Our results validate the prior work and support specific genetic pathways for risk among NHL subtypes.

Pesticide Residues in Fresh Fruit and Vegetables from Farm to Fork in the Kampala Metropolitan Area, Uganda.

This study assessed concentrations of pesticide residues in fruits and vegetables from farm-to-fork in Kampala Metropolitan Area, Uganda. A total of 160 samples of fruit and vegetables collected from farms, markets, streets, restaurants and homes were analysed using liquid chromatography-tandem mass spectrometry; and Gas Chromatograph-Mass Spectrometer for dithiocarbamates. Multiple pesticide residues were detected in majority of the samples (95.6%). The proportions of the most frequently detected pesticides residue classes were organophosphates (91.3%), carbamates (67.5%), pyrethroids (60.0%) dithiocarbamates (48.1%) and neonicotinoids (42.5%). Among organophosphates, propotamophos, acephate, fonofos, monocrotophos and dichlorvos were the most detected active ingredients; aminocarb, methomyl and pirimicarb were the commonly detected carbamates; while imidacloprid, a neonicotinoid and lambda-cyhalothrin, pyrethroid were also highly detected. Twenty-seven pesticide were tested at all stages, of which the concentrations either decreased or increased along the chain. Multiple pesticide residues occurred in commonly consumed fruit and vegetables with decreasing or increasing concentrations from farm-to-fork.

An assessment of health risks posed by consumption of pesticide residues in fruits and vegetables among residents in the Kampala Metropolitan Area in Uganda.

Background: Pesticide use for fruits and vegetable production in Uganda may result in presence of residues on produce which may pose health risks to consumers. Uganda does not have an established system for monitoring pesticide residues in fruits and vegetables and assessing potential health risks. This research aimed to conduct a health risk assessment of presence of pesticide residues in fruits and vegetables in the Kampala Metropolitan Area in Uganda. Method: Pesticides were measured in 160 fruits and vegetables samples collected at farms, markets, street vendors, restaurants and homes; and analysed using liquid chromatography-tandem mass spectrometry and gas chromatography-mass spectrometry. Fruit and vegetable consumption information was collected from 2177 people. Pesticide concentrations were compared with European Union maximum residual limits (MRLs). Mean values of pesticide concentration residues found in the sample of fruits and vegetables; and fruits and vegetables intake and body weight were used to calculate the estimated daily intake (EDI) of pesticide residues. EDI values were compared with acceptable daily intakes (ADI) to calculate the hazard quotient by age group, and stage at which consumption happens along the chain. Results: Overall, 57 pesticides were detected in fruits and vegetables from farm to fork. Of the 57, 39 pesticides were detected in all the fruits and vegetables studied. Concentrations of fonofos, fenitrothion and fenhexamid were above the European Union MRLs in some samples. Hazard quotients based on dietary ingestion scenarios for 18 pesticides, including dichlorvos (444) alanycarb (314), fonofos (68), fenitrothion (62), dioxacarb (55) and benfuracarb (24) and others, were above 1, indicating the possibility of chronic health risk to consumers. Chronic health risk decreased with age but was stable for stage at which consumption happens along the food chain. The number of pesticides with EDI greater than the ADI decreased with increase in age; with 18, 13, 9, 11, 8, 9, and 9 pesticides for age groups < 5, 5-12, 13-19, 20-25, 36-49 and ≥ 50 respectively. Conclusion: Chronic dietary pesticide exposures to Ugandans are likely common, and for some pesticides result in exposure exceeding health-based benchmarks. Risks were highest for younger participants. There is an urgent need to increase monitoring and regulation of pesticides in fruits and vegetables in order to protect consumers, especially the children who are vulnerable to the adverse effects of pesticides. Supplementary Information: The online version contains supplementary material available at 10.1186/s40550-022-00090-9.

The impact of prenatal and early-life arsenic exposure on epigenetic age acceleration among adults in Northern Chile.

Exposure to arsenic affects millions of people globally. Changes in the epigenome may be involved in pathways linking arsenic to health or serve as biomarkers of exposure. This study investigated associations between prenatal and early-life arsenic exposure and epigenetic age acceleration (EAA) in adults, a biomarker of morbidity and mortality. DNA methylation was measured in peripheral blood mononuclear cells (PBMCs) and buccal cells from 40 adults (median age = 49 years) in Chile with and without high prenatal and early-life arsenic exposure. EAA was calculated using the Horvath, Hannum, PhenoAge, skin and blood, GrimAge, and DNA methylation telomere length clocks. We evaluated associations between arsenic exposure and EAA using robust linear models. Participants classified as with and without arsenic exposure had a median drinking water arsenic concentration at birth of 555 and 2 µg/l, respectively. In PBMCs, adjusting for sex and smoking, exposure was associated with a 6-year PhenoAge acceleration [B (95% CI) = 6.01 (2.60, 9.42)]. After adjusting for cell-type composition, we found positive associations with Hannum EAA [B (95% CI) = 3.11 (0.13, 6.10)], skin and blood EAA [B (95% CI) = 1.77 (0.51, 3.03)], and extrinsic EAA [B (95% CI) = 4.90 (1.22, 8.57)]. The association with PhenoAge acceleration in buccal cells was positive but not statistically significant [B (95% CI) = 4.88 (-1.60, 11.36)]. Arsenic exposure limited to early-life stages may be associated with biological aging in adulthood. Future research may provide information on how EAA programmed in early life is related to health.

Requirement for invariant chain in macrophages for Mycobacterium tuberculosis replication and CD1d antigen presentation.

Mycobacterium tuberculosis is an intracellular bacterium that persists in phagosomes of myeloid cells. M. tuberculosis-encoded factors support pathogen survival and reduce fusion of phagosomes with bactericidal lysosomal compartments. It is, however, not entirely understood if host factors that mediate endosomal fusion affect M. tuberculosis intracellular localization and survival. Neither is it known if endosomal fusion influences induction of host immune reactivity by M. tuberculosis-infected cells. Lysosomal degradation of M. tuberculosis appears to be pivotal for making available lipid substrates for assembly into lipid-CD1d complexes to allow activation of CD1d-restricted invariant natural killer T (iNKT) cells. To clarify the role for endosomal fusion in M. tuberculosis survival and induction of host CD1d-mediated immune defense, we focused our studies on the invariant chain (Ii). Ii regulates endosome docking and fusion and thereby controls endosomal transport. Through direct binding, Ii also directs intracellular transport of the class II major histocompatibility complex and CD1d. Our findings demonstrate that upon infection of Ii-knockout (Ii(-/-)) macrophages, M. tuberculosis is initially retained in early endosomal antigen 1-positive lysosomal-associated membrane protein 1-negative phagosomes, which results in slightly impaired pathogen replication. The absence of Ii did not affect the ability of uninfected and infected macrophages to produce nitric oxide, tumor necrosis factor alpha, or interleukin-12. However, induction of cell surface CD1d was impaired in infected Ii(-/-) macrophages, and CD1d-restricted iNKT cells were unable to suppress bacterial replication when they were cocultured with M. tuberculosis-infected Ii(-/-) macrophages. Thus, while the host factor Ii is not essential for the formation of the M. tuberculosis-containing vacuole, its presence is crucial for iNKT cell recognition of infected macrophages.

Distinct requirements for CD1d intracellular transport for development of V(alpha)14 iNKT cells.

The positive selection of V(alpha)14 invariant (i)NKT cells in mice requires CD1d-mediated Ag presentation by CD4(+)CD8(+) thymocytes. Maturation of newly selected iNKT cells continues in the periphery and also involves CD1d expression. CD1d molecules acquire Ags for presentation in endosomal compartments, to which CD1d molecules have access through an intrinsic CD1d-encoded tyrosine motif and by association with the class II MHC chaperone, invariant chain. In this study, we report the generation of mice in which all CD1d is replaced by CD1d-enhanced yellow fluorescent fusion protein (EYFP). CD1d-EYFP molecules are stable, present lipid Ags, and have near normal subcellular distribution. CD1d-EYFP molecules mediated positive selection of V(alpha)14 iNKT cell precursors at decreased efficiency, caused a delay in their terminal maturation, and did not invoke V(alpha)14iNKT cell effector function as wild-type CD1d could. Using these mice, we show that the intrinsic CD1d-encoded sorting motif mediates thymic selection and activation of V(alpha)14 iNKT cells by professional APCs, while for peripheral terminal differentiation the intrinsic CD1d sorting motif is dispensable.

Cell-Based Bioassay to Screen Environmental Chemicals and Human Serum for Total Glucocorticogenic Activity.

Glucocorticoids are steroid hormones that have systemic effects that are mediated by the glucocorticoid receptor. Environmental chemicals that disrupt glucocorticoid receptor signaling and/or glucocorticoid homeostasis could adversely affect the health of human and nonhuman vertebrates. A major challenge in identifying environmental chemicals that alter glucocorticoid receptor signaling and/or glucocorticoid homeostasis is a lack of adequate screening methods. We developed a cell-based bioassay to measure total glucocorticogenic activity (TGA) of environmental chemicals and human serum. Human MDA-MB-231 breast cancer cells were stably transfected with a luciferase reporter gene driven by 3 tandem glucocorticoid-response elements. Dose-response curves for 6 glucocorticoids and 4 non-glucocorticoid steroid hormones were generated to evaluate the specificity of the bioassay. Cells were also optimized to measure TGA of 176 structurally diverse environmental chemicals and human serum samples in a high-throughput format. Reporter activity was glucocorticoid-specific and induced 400-fold by 1 µM dexamethasone. Furthermore, 3 of the screened chemicals (3,4,4'-trichlorocarbanilide, isopropyl-N-phenylcarbamate, and benzothiazole derivative 2-[4-chlorophenyl]-benzothiazole) potentiated cortisol-induced glucocorticoid receptor activity. Serum TGA estimates from the bioassay were highly correlated with a cortisol enzyme-linked immunosorbent assay. The present study establishes an in vitro method to rapidly screen environmental chemicals and human serum for altered glucocorticogenic activity. Future studies can utilize this tool to quantify the joint effect of endogenous glucocorticoids and environmental chemicals. Environ Toxicol Chem 2021;40:177-186. © 2020 SETAC.

Infectability of human BrainSphere neurons suggests neurotropism of SARS-CoV-2

Reports from Wuhan suggest that 36% of COVID-19 patients show neurological symptoms, and cases of viral encephalitis have been reported, suggesting that the virus is neurotropic under unknown circumstances. This is well established for other coronaviruses. In order to understand why some patients develop such symptoms and others do not, we address herein the infectability of the central nervous system (CNS). Reports that the ACE2 receptor ­ critical for virus entry into lung cells ­ is found in different neurons support this expectation. We employed a human induced pluripotent stem cell (iPSC)- derived BrainSphere model, which we used earlier for Zika, Dengue, HIV and John Cunningham virus infection studies. We detected the expression of the ACE2 receptor, but not TMPRSS2, in the model. Incubating the BrainSpheres for 6 hours with SARS-CoV-2 at a multiplicity of infection (MOI) of 0.1 led to infection of a fraction of neural cells with replication of the virus evident at 72 hpi. Virus particles were found in the neuronal cell body extending into apparent neurite structures. PCR measurements corroborated the replication of the virus, suggesting at least a tenfold increase in virus copies per total RNA. Leveraging state-of-the-art 3D organotypic cell culture, which has been shown to allow both virus infection and modeling of (developmental) neurotoxicity but is at the same time simple enough to be transferred and used in a BSL-3 environment, we demonstrate, for the first time, the potential critically important neurotropism of SARS-CoV-2.

The exposome - a new approach for risk assessment.

Complementing the human genome with an exposome reflects the increasingly obvious impact of environmental exposure, which far exceeds the role of genetics, on human health. Considering the complexity of exposures and, in addition, the reactions of the body to exposures - i.e., the exposome - reverses classical exposure science where the precise measurement of single or few exposures is associated with specific health or environmental effects. The complete description of an individual's exposome is impossible; even less so is that of a population. We can, however, cast a wider net by foregoing some rigor in assessment and compensating with the statistical power of rich datasets. The advent of omics technologies enables a relatively cheap, high-content description of the biological effects of substances, especially in tissues and biofluids. They can be combined with many other rich data-streams, creating big data of exposure and effect. Computational methods increasingly allow data integration, discerning the signal from the noise and formulating hypotheses of exposure-effect relationships. These can be followed up in a targeted way. With a better exposure element in the risk equation, exposomics - new kid on the block of risk assessment - promises to identify novel exposure (interactions) and health/environment effect associations. This may also create opportunities to prioritize the more relevant chemicals for risk assessment, thereby lowering the burden on hazard assessment in an expo-sure-driven approach. Technological developments and synergies between approaches, quality assurance (ultimately as Good Exposome Practices), and the integration of mechanistic thinking will advance this approach.