Application of a new approach method to assess the hazard of complex legacy contaminated groundwater mixtures on fathead minnows in outdoor mesocosms.

Assessing the environmental risks of contaminated groundwater presents significant challenges due to its often-complex chemical composition and to dynamic processes affecting exposure of organisms in receiving surface waters. The objective of this study was to characterize the effects of groundwater collected from a legacy contaminated industrial site, in fish under environmentally relevant conditions. A 21-day fish short-term reproduction assay was conducted in outdoor wetland mesocosms by exposing adult fathead minnows (Pimephales promelas) to graded concentrations of groundwater (1 %, 3 %, and 6 %). Offspring were held in mesocosms up to four days post-hatch to apply a new approach method (NAM), the EcoToxChip™, to explore whether traditional apical endpoints could be predicted using an alternative mechanistic approach. None of the groundwater concentrations used in this study were lethal to fish. There was greater cumulative number of eggs produced at the highest concentration of exposure. However, no abnormal histological appearance was observed in the liver and gonads of fish and no significant effect was observed in the relative expression of genes, tubercle counts, and erythrocyte micronuclei counts compared to the negative control. Food availability in the mesocosms was also assessed and the abundance of zooplankton increased in all groundwater-treated mesocosms. Fathead minnow findings are in contrast to those obtained from previous controlled laboratory studies that revealed significant genotoxicity, hepatotoxicity, and reprotoxicity of the same mixtures. Several factors could explain these observations, including the aging of groundwater in mesocosms before fish addition resulting in photo- and biodegradation and binding to sediments of toxic components. Our static exposure scenario likely underestimated realistic exposure scenarios where groundwater inflow to surface water is generally semi-continuous. Nevertheless, focused transcriptome analysis using EcoToxChips also observed greater toxicity during previous laboratory tests compared to mesocosm scenarios, and thus, our results support the use of this NAM in the ecological risk assessment of contaminated groundwater.

Nuclear factor of activated T-cells 5 is indispensable for a balanced adaptive transcriptional response of lung endothelial cells to hypoxia.

AIMS: Chronic hypoxia causes detrimental structural alterations in the lung, which may cause pulmonary hypertension and are partially mediated by the endothelium. While its relevance for the development of hypoxia-associated lung diseases is well known, determinants controlling the initial adaptation of the lung endothelium to hypoxia remain largely unexplored. METHODS AND RESULTS: We revealed that hypoxia activates the transcription factor nuclear factor of activated T-cells 5 (NFAT5) and studied its regulatory function in murine lung endothelial cells (MLECs). EC-specific knockout of Nfat5 (Nfat5(EC)-/-) in mice exposed to normobaric hypoxia (10% O2) for 21 days promoted vascular fibrosis and aggravated the increase in pulmonary right ventricular systolic pressure as well as right ventricular dysfunction as compared with control mice. Microarray- and single-cell RNA-sequencing-based analyses revealed an impaired growth factor-, energy-, and protein-metabolism-associated gene expression in Nfat5-deficient MLEC after exposure to hypoxia for 7 days. Specifically, loss of NFAT5 boosted the expression and release of platelet-derived growth factor B (Pdgfb)-a hypoxia-inducible factor 1 alpha (HIF1α)-regulated driver of vascular smooth muscle cell (VSMC) growth-in capillary MLEC of hypoxia-exposed Nfat5(EC)-/- mice, which was accompanied by intensified VSMC coverage of distal pulmonary arteries. CONCLUSION: Collectively, our study shows that early and transient subpopulation-specific responses of MLEC to hypoxia may determine the degree of organ dysfunction in later stages. In this context, NFAT5 acts as a protective transcription factor required to rapidly adjust the endothelial transcriptome to cope with hypoxia. Specifically, NFAT5 restricts HIF1α-mediated Pdgfb expression and consequently limits muscularization and resistance of the pulmonary vasculature.

Inconsistent Transcriptomic Responses to Hexabromocyclododecane in Japanese Quail: A Comparative Analysis of Results From Four Different Study Designs.

Efforts to use transcriptomics for toxicity testing have classically relied on the assumption that chemicals consistently produce characteristic transcriptomic signatures that are reflective of their mechanism of action. However, the degree to which transcriptomic responses are conserved across different test methodologies has seldom been explored. With increasing regulatory demand for New Approach Methods (NAMs) that use alternatives to animal models and high-content approaches such as transcriptomics, this type of comparative analysis is needed. We examined whether common genes are dysregulated in Japanese quail (Coturnix japonica) liver following sublethal exposure to the flame retardant hexabromocyclododecane (HBCD), when life stage and test methodologies differ. The four exposure scenarios included one NAM: Study 1-early-life stage (ELS) exposure via a single egg injection, and three more traditional approaches; Study 2-adult exposure using a single oral gavage; Study 3-ELS exposure via maternal deposition after adults were exposed through their diet for 7 weeks; and Study 4-ELS exposure via maternal deposition and re-exposure of nestlings through their diet for 17 weeks. The total number of differentially expressed genes (DEGs) detected in each study was variable (Study 1, 550; Study 2, 192; Study 3, 1; Study 4, 3) with only 19 DEGs shared between Studies 1 and 2. Factors contributing to this lack of concordance are discussed and include differences in dose, but also quail strain, exposure route, sampling time, and HBCD stereoisomer composition. The results provide a detailed overview of the transcriptomic responses to HBCD at different life stages and routes of exposure in a model avian species and highlight certain challenges and limits of comparing transcriptomics across different test methodologies. Environ Toxicol Chem 2024;00:1-11. © 2024 The Author(s). Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

AOP-Anchored Transcriptome Analysis Catalogue Accelerates the Discovery of Environmental Toxicants in Zebrafish.

Current toxicity screening approaches to evaluate the vast number of environmental chemicals that require assessment are hampered due to their significant costs, time requirements, and reliance on live animal testing. The aim of the present study was to develop an adverse outcome pathway (AOP)-anchored transcriptome analysis (AATA) catalogue to expedite the discovery of environmental toxicants. 437 AOPs from the AOPwiki (https://aopwiki.org/) and 2280 transcriptomics data sets from NCBI Gene Expression Omnibus (GEO) and EMBL-EBI ArrayExpress (AE) repositories were comprehensively reviewed and analyzed. By using the differentially expressed molecular key event (mKE) genes as connection nodes, we created a large-scale environmental substance─target gene (mKE)─predicted adverse outcomes (SGAs) network that included 78 substances, 1099 genes, and 354 adverse outcomes (AOs). To validate the reliability of the network, comprehensive literature verification was conducted. We demonstrated that 164 of the 354 AOs identified have been previously characterized in the literature. The results for 136 of these AOs were consistent with the predictions of the AATA catalogue, representing an accuracy rate of 82.9%. Besides, distinct patterns in molecular KEs and AOs among categories of substances, such as biocides and metals, were demonstrated. Some representative substances, including atrazine and copper, pose significant risks to fish at various levels of biological organization. Moreover, experimental verification of the AATA predictions was conducted, including exposures of zebrafish to perfluorooctanesulfonate, cresyl diphenyl phosphate, and lanthanum. Results demonstrated consistency with predictions of the AATA catalogue, with an accuracy rate of 92.3%. Collectively, the present findings support the AATA catalogue as an efficient and promising platform for identifying environmental toxicants to fish and thereby provide novel insights into the understanding of potential risks of environmental contaminants.

Characterization of Adverse Outcomes from Legacy-Contaminated Groundwater Exposure to Early Life Stages of Fathead Minnow.

Complex mixtures of chemicals present in groundwater at legacy-contaminated industrial sites can pose significant risks to adjacent surface waters. The combination of short-term molecular and chronic apical effect assessments is a promising approach to characterize the potential hazard of such complex mixtures. The objectives of this study were to: (1) assess the apical effects (survival, growth, development, and liver histopathology) after chronic exposure of early life stages (ELSs) of fathead minnows (FHM; Pimephales promelas) to contaminated groundwater from a legacy-contaminated pesticide manufacturing and packaging plant, and (2) identify possible molecular mechanisms responsible for these effects by comparing results to mechanistic outcomes previously determined by a short-term reduced transcriptome assay (EcoToxChips). This study revealed a significant increase in mortality and prevalence of spinal curvatures, as well as a significant reduction in the length of FHMs exposed to the groundwater mixtures in a concentration-dependent manner. There was an increasing trend in the prevalence of edema in FHMs, though not significantly different from controls. Additionally, no histopathological effects were observed in the liver of FHMs exposed to the groundwater mixtures. Short-term molecular outcomes determined in a parallel study were found to be informative of chronic apical outcomes, including cardiotoxicity, spinal deformities, and liver toxicity. Overall, the results observed in this study demonstrated that short-term transcriptomics analyses could support the hazard assessment of complex contaminated sites.

Developing an Approach for Integrating Chemical Analysis and Transcriptional Changes to Assess Contaminants in Water, Sediment, and Fish.

Pharmaceuticals in aquatic environments pose threats to aquatic organisms because of their continuous release and potential accumulation. Monitoring methods for these contaminants are inadequate, with targeted analyses falling short in assessing water quality's impact on biota. The present study advocates for integrated strategies combining suspect and targeted chemical analyses with molecular biomarker approaches to better understand the risks posed by complex chemical mixtures to nontarget organisms. The research aimed to integrate chemical analysis and transcriptome changes in fathead minnows to prioritize contaminants, assess their effects, and apply this strategy in Wascana Creek, Canada. Analysis revealed higher pharmaceutical concentrations downstream of a wastewater-treatment plant, with clozapine being the most abundant in fathead minnows, showing notable bioavailability from water and sediment sources. Considering the importance of bioaccumulation factor and biota-sediment accumulation factor in risk assessment, these coefficients were calculated based on field data collected during spring, summer, and fall seasons in 2021. Bioaccumulation was classified as very bioaccumulative with values >5000 L kg-1, suggesting the ability of pharmaceuticals to accumulate in aquatic organisms. The study highlighted the intricate relationship between nutrient availability, water quality, and key pathways affected by pharmaceuticals, personal care products, and rubber components. Prioritization of these chemicals was done through suspect analysis, supported by identifying perturbed pathways (specifically signaling and cellular processes) using transcriptomic analysis in exposed fish. This strategy not only aids in environmental risk assessment but also serves as a practical model for other watersheds, streamlining risk-assessment processes to identify environmental hazards and work toward reducing risks from contaminants of emerging concern. Environ Toxicol Chem 2024;43:2252-2273. © 2024 SETAC.

Time-course of oral toxicity to contaminated groundwater in male Sprague Dawley rats.

Assessing toxicity of complex mixtures of contaminants from industrial sites with historic and ongoing contamination remains a challenge for risk assessors. Groundwater from a pesticide packaging site in Canada containing a complex mixture of known and unknown contaminants was examined in male rats to determine the target organ toxicity. This study determined the time-course of toxicity (7, 14, 28, and 60 days) following ad libitum oral exposure to 0.05% v/v contaminated groundwater compared to tap water (control) in male Sprague Dawley rats (n=5 /group/time). Exposure to groundwater resulted in inflammation, indicated by a statistically significant increase in plasma lymphocyte and neutrophil counts on days 7 and 60, respectively, but a reduction in the plasma alpha 2 macroglobulin levels by day 60. Gonadotoxicity was indicated by a reduced Johnsen score (grading spermatogenesis) in all exposed groups at all time points, while seminiferous epithelial height was reduced on days 7, 14, and 28 compared to controls. Plasma testosterone was reduced in exposed groups on days 7 and 28, accompanied by elevated testicular lipid peroxidation at all time points compared to control. In contrast, lipid peroxidation in the lungs from exposed rats was elevated on days 7, 14, and 28. Plasma symmetric dimethylarginine was elevated on day 14 in the exposed group indicating renal impairment. Taken together, these results indicate that testes, kidney, immune and lung are target organs for the contaminated groundwater from this industrial site. The current study highlights the challenge in hazard assessment for complex mixtures and highlights the need for effects-directed analysis and the continued, albeit limited, use of animal models in toxicity testing.

Zyxin is important for the stability and function of podocytes, especially during mechanical stretch.

Podocyte detachment due to mechanical stress is a common issue in hypertension-induced kidney disease. This study highlights the role of zyxin for podocyte stability and function. We have found that zyxin is significantly up-regulated in podocytes after mechanical stretch and relocalizes from focal adhesions to actin filaments. In zyxin knockout podocytes, we found that the loss of zyxin reduced the expression of vinculin and VASP as well as the expression of matrix proteins, such as fibronectin. This suggests that zyxin is a central player in the translation of mechanical forces in podocytes. In vivo, zyxin is highly up-regulated in patients suffering from diabetic nephropathy and in hypertensive DOCA-salt treated mice. Furthermore, zyxin loss in mice resulted in proteinuria and effacement of podocyte foot processes that was measured by super resolution microscopy. This highlights the essential role of zyxin for podocyte maintenance in vitro and in vivo, especially under mechanical stretch.

Genetic ablation of Lmp2 increases the susceptibility for impaired cardiac function.

Proteasome degradation is an integral part of cellular growth and function. Proteasomal intervention may mitigate adverse myocardial remodeling, but is associated with the onset of heart failure. Previously, we have demonstrated that increasing abundance of cardiac Lmp2 and its incorporation into proteasome complexes is an endogenous mechanism for proteasome regulation during hypertrophic remodeling of the heart induced by chronic ß-adrenoreceptor stimulation. Here, we investigated whether Lmp2 is required for myocardial remodeling not driven by inflammation and show that Lmp2 is a tipping element for growth and function in the heart but not for proteasome insufficiency. While it has no apparent impact under unchallenged conditions, myocardial remodeling without Lmp2 exacerbates hypertrophy and restricts cardiac function. Under chronic ß-adrenoreceptor stimulation, as seen in the development of cardiovascular disease and the manifestation of heart failure, genetic ablation of Lmp2 in mice caused augmented concentric hypertrophy of the left ventricle. While the heart rate was similarly elevated as in wildtype, myocardial contractility was not maintained without Lmp2, and apparently uncoupled of the ß-adrenergic response. Normalized to the exacerbated myocardial mass, contractility was reduced by 41% of the pretreatment level, but would appear preserved at absolute level. The lack of Lmp2 interfered with elevated 26S proteasome activities during early cardiac remodeling reported previously, but did not cause bulk proteasome insufficiency, suggesting the Lmp2 containing proteasome subpopulation is required for a selected group of proteins to be degraded. In the myocardial interstitium, augmented collagen deposition suggested matrix stiffening in the absence of Lmp2. Indeed, echocardiography of left ventricular peak relaxation velocity (circumferential strain rate) was reduced in this treatment group. Overall, targeting Lmp2 in a condition mimicking chronic ß-adrenoreceptor stimulation exhibited the onset of heart failure. Anticancer therapy inhibiting proteasome activity, including Lmp2, is associated with adverse cardiac events, in particular heart failure. Sparing Lmp2 may be an avenue to reduce adverse cardiac events when chronic sympathetic nervous system activation cannot be excluded.

Hazard assessment of complex legacy-contaminated groundwater mixtures using a novel approach method in adult fathead minnows.

Traditional risk assessment methods face challenges in the determination of drivers of toxicity for complex mixtures such as those present at legacy-contaminated sites. Bioassay-driven analysis across several levels of biological organization represents an approach to address these obstacles. This study aimed to apply a novel transcriptomics tool, the EcoToxChip, to characterize the effects of complex mixtures of contaminants in adult fathead minnows (FHMs) and to compare molecular response patterns to higher-level biological responses. Adult FHMs were exposed for 4 and 21 days to groundwater mixtures collected from a legacy-contaminated site. Adult FHM showed significant induction of micronuclei in erythrocytes, decrease in reproductive capacities, and some abnormal appearance of liver histology. Parallel EcoToxChip analyses showed a high proportion of upregulated genes and a few downregulated genes characteristic of compensatory responses. The three most enriched pathways included thyroid endocrine processes, transcription and translation cellular processes, and xenobiotics and reactive oxygen species metabolism. Several of the most differentially regulated genes involved in these biological pathways could be linked to the apical outcomes observed in FHMs. We concluded that molecular responses as determined by EcoToxChip analysis show promise for informing of apical outcomes and could support risk assessments of complex contaminated sites.

Cross-species apical microinjected selenomethionine toxicity in embryo-larval fishes.

Selenium (Se) is an essential micronutrient that becomes toxic when exposures minimally exceed those that are physiologically required. Studies on Se contaminated aquatic environments have identified that embryo-larval fishes are at particular risk of Se toxicity, primarily due to maternal Se transfer to developing eggs during oogenesis. This study emulated these exposures in embryo-larval fathead minnow (FHM), rainbow trout (RBT), white sucker (WSu), and white sturgeon (WSt) using embryonic selenomethionine (SeMet) microinjections. Adverse Se-outcomes observed across these species included spinal and edematous deformities, total individuals deformed, and reduced survival. Spinal deformity was the most sensitive sublethal endpoint and developed at the lowest concentrations in WSt (10 % effects concentration (EC10) = 12.42 µg (total) Se/g dry weight (d.w.)) followed by WSu (EC10 = 14.49 µg Se/g d.w.) and FHM (EC10 = 18.10 µg Se/g d.w.). High mortality was observed in RBT, but SeMet influences were confounded by the species' innate sensitivity to the microinjections themselves. 5 % hazardous concentrations derived across exposure type data subsets were ∼49 % higher when derived from within-species maternal transfer exclusive data as opposed to all, or within-species microinjection exclusive, data. These results support the current exclusion of SeMet microinjections during regulatory guideline derivation and their inclusion when studying mechanistic Se toxicity across phylogenetically distant fishes.

Hepatic Transcriptomic Responses to Ethinylestradiol in Embryonic Japanese Quail and Double-Crested Cormorant.

Understanding species differences in sensitivity to toxicants is a critical issue in ecotoxicology. We recently established that double-crested cormorant (DCCO) embryos are more sensitive than Japanese quail (JQ) to the developmental effects of ethinylestradiol (EE2). We explored how this difference in sensitivity between species is reflected at a transcriptomic level. The EE2 was dissolved in dimethyl sulfoxide and injected into the air cell of eggs prior to incubation at nominal concentrations of 0, 3.33, and 33.3 µg/g egg weight. At midincubation (JQ 9 days; DCCO 16 days), livers were collected from five embryos/treatment group for RNA sequencing. Data were processed and analyzed using EcoOmicsAnalyst and ExpressAnalyst. The EE2 exposure dysregulated 238 and 1,987 genes in JQ and DCCO, respectively, with 78 genes in common between the two species. These included classic biomarkers of estrogen exposure such as vitellogenin and apovitellenin. We also report DCCO-specific dysregulation of Phase I/II enzyme-coding genes and species-specific transcriptional ontogeny of vitellogenin-2. Twelve Kyoto Encyclopedia of Genes and Genomes pathways and two EcoToxModules were dysregulated in common in both species including the peroxisome proliferator-activated receptor (PPAR) signaling pathway and fatty acid metabolism. Similar to previously reported differences at the organismal level, DCCO were more responsive to EE2 exposure than JQ at the gene expression level. Our description of differences in transcriptional responses to EE2 in early life stage birds may contribute to a better understanding of the molecular basis for species differences. Environ Toxicol Chem 2024;43:772-783. © 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Comparing Transcriptomic Responses to Chemicals Across Six Species Using the EcoToxChip RNASeq Database.

The EcoToxChip project includes RNA-sequencing data from experiments involving model (Japanese quail, fathead minnow, African clawed frog) and ecological (double-crested cormorant, rainbow trout, northern leopard frog) species at multiple life stages (whole embryo and adult) exposed to eight chemicals of environmental concern known to perturb a wide range of biological systems (ethinyl estradiol, hexabromocyclododecane, lead, selenomethionine, 17ß trenbolone, chlorpyrifos, fluoxetine, and benzo[a]pyrene). The objectives of this short communication were to (1) present and make available this RNA-sequencing database (i.e., 724 samples from 49 experiments) under the FAIR principles (FAIR data are data which meet principles of findability, accessibility, interoperability, and reusability), while also summarizing key meta-data attributes and (2) use ExpressAnalyst (including the Seq2Fun algorithm and EcoOmicsDB) to perform a comparative transcriptomics analysis of this database focusing on baseline and differential transcriptomic changes across species-life stage-chemical combinations. The database is available in NCBI GEO under accession number GSE239776. Across all species, the number of raw reads per sample ranged between 13 and 58 million, with 30% to 79% of clean reads mapped to the "vertebrate" subgroup database in EcoOmicsDB. Principal component analyses of the reads illustrated separation across the three taxonomic groups as well as some between tissue types. The most common differentially expressed gene was CYP1A1 followed by CTSE, FAM20CL, MYC, ST1S3, RIPK4, VTG1, and VIT2. The most common enriched pathways were metabolic pathways, biosynthesis of cofactors and biosynthesis of secondary metabolites, and chemical carcinogenesis, drug metabolism, and metabolism of xenobiotics by cytochrome P450. The RNA-sequencing database in the present study may be used by the research community for multiple purposes, including, for example, cross-species investigations, in-depth analyses of a particular test compound, and transcriptomic meta-analyses. Environ Toxicol Chem 2024;00:1-6. © 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Interspecies Differences in 6PPD-Quinone Toxicity Across Seven Fish Species: Metabolite Identification and Semiquantification.

N-(1,3-Dimethylbutyl)-N'-phenyl-p-phenylenediamine-quinone (6PPD-Q) is a recently identified contaminant that originates from the oxidation of the tire antidegradant 6PPD. 6PPD-Q is acutely toxic to select salmonids at environmentally relevant concentrations, while other fish species display tolerance to concentrations that surpass those measured in the environment. The reasons for these marked differences in sensitivity are presently unknown. The objective of this research was to explore potential toxicokinetic drivers of species sensitivity by characterizing biliary metabolites of 6PPD-Q in sensitive and tolerant fishes. For the first time, we identified an O-glucuronide metabolite of 6PPD-Q using high-resolution mass spectrometry. The semiquantified levels of this metabolite in tolerant species or life stages, including white sturgeon (Acipenser transmontanus), chinook salmon (Oncorhynchus tshawytscha), westslope cutthroat trout (Oncorhynchus clarkii lewisi), and nonfry life stages of Atlantic salmon (Salmo salar), were greater than those in sensitive species, including coho salmon (Oncorhynchus kisutch), brook trout (Salvelinus fontinalis), and rainbow trout (Oncorhynchus mykiss), suggesting that tolerant species might detoxify 6PPD-Q more effectively. Thus, we hypothesize that differences in species sensitivity are a result of differences in basal expression of biotransformation enzyme across various fish species. Moreover, the semiquantification of 6PPD-Q metabolites in bile extracted from wild-caught fish might be a useful biomarker of exposure to 6PPD-Q, thereby being valuable to environmental monitoring and risk assessment.

Characterization of molecular and apical effects of legacy-contaminated groundwater on early life stages of fathead minnows.

Mechanistic toxicology approaches represent a promising alternative to traditional live animal testing; however, the often-noted uncertainties concerning the linkages between effects observed at molecular and apical levels curtails the adoption of such approaches. The objective of this study was to apply a novel transcriptomics tool, EcoToxChips, to characterize the effects of complex mixtures of contaminants in fish and to compare molecular response patterns to higher-level biological responses including swimming behavior, deformities, and mortality. Fathead minnow (FHM) embryos were exposed for seven days to increasing concentrations of groundwater collected from moderate (MIAZ) and high (HIAZ) industrial activity zones of a legacy contaminated site. There was a concentration-dependent disruption of photo-dependent swimming responses associated with avoidance behavior patterns and spinal deformities (HIAZ and MIAZ), and an induction of pericardial edema and mortality (HIAZ-10%). Parallel EcoToxChip analyses showed a shift from a majority of upregulated genes at lower concentrations to a majority of downregulated genes at higher concentrations for both treatment conditions. Many of the significantly differentially regulated genes were involved in biological pathways including induction of oxidative stress, activating of several metabolic processes and growth, cell death, and inhibition of signal transduction signaling processes. Several contaminants present in the groundwater mixtures could have contributed to an exceedance of antioxidant system capacities that possibly led to the deformities, altered swimming behaviours, and mortality observed in FHMs. Therefore, molecular response patterns could be linked to apical outcomes observed in this study. Overall, the results observed in this study demonstrate that transcriptomics approaches such as the EcoToxChip system could be supportive of risk assessment of complex contaminated sites.

Impact of the -1T>C single-nucleotide polymorphism of the CD40 gene on the development of endothelial dysfunction in a pro-diabetic microenvironment.

BACKGROUND AND AIMS: Hyperglycemia reinforces pro-inflammatory conditions that enhance CD40 expression in endothelial cells (EC). Thymine to cytosine transition (-1T > C) in the promoter of the CD40 gene (rs1883832) further increases the abundance of CD40 protein on the EC surface. This study examines potential associations of the -1T > C SNP of the CD40 gene with type 1 (T1D) or type 2 (T2D) diabetes. Moreover, it investigates the impact of a pro-inflammatory diabetic microenvironment on gene expression in human cultured umbilical vein EC (HUVEC) derived from CC- vs. TT-genotype donors. METHODS: Tetra-ARMS-PCR was used to compare genotype distribution in 252 patients with diabetes. Soluble CD40 ligand (sCD40L) and soluble CD40 receptor (sCD40) plasma levels were monitored using ELISA. RNA-sequencing was performed with sCD40L-stimulated CC- and TT-genotype HUVEC. Quantitative PCR, Western blot, multiplex-sandwich ELISA array, and immunocytochemistry were used to analyse changes in gene expression in these cells. RESULTS: Homozygosity for the C-allele was associated with a significant 4.3-fold higher odds of developing T2D as compared to individuals homozygous for the T-allele. Inflammation and endothelial-to-mesenchymal transition (EndMT) driving genes were upregulated in CC-genotype but downregulated in TT-genotype HUVEC when exposed to sCD40L. Expression of EndMT markers significantly increased while that of endothelial markers decreased in HUVEC following exposure to hyperglycemia, tumour necrosis factor-α and sCD40L. CONCLUSIONS: The -1T > C SNP of the CD40 gene is a risk factor for T2D. Depending on the genotype, it differentially affects gene expression in human cultured EC. CC-genotype HUVEC adopt a pro-inflammatory and intermediate EndMT-like phenotype in a pro-diabetic microenvironment.

Characterisation of Lipoma-Preferred Partner as a Novel Mechanotransducer in Vascular Smooth Muscle Cells.

In arteries and arterioles, a chronic increase in blood pressure raises wall tension. This continuous biomechanical strain causes a change in gene expression in vascular smooth muscle cells (VSMCs) that may lead to pathological changes. Here we have characterised the functional properties of lipoma-preferred partner (LPP), a Lin11-Isl1-Mec3 (LIM)-domain protein, which is most closely related to the mechanotransducer zyxin but selectively expressed by smooth muscle cells, including VSMCs in adult mice. VSMCs isolated from the aorta of LPP knockout (LPP-KO) mice displayed a higher rate of proliferation than their wildtype (WT) counterparts, and when cultured as three-dimensional spheroids, they revealed a higher expression of the proliferation marker Ki 67 and showed greater invasion into a collagen gel. Accordingly, the gelatinase activity was increased in LPP-KO but not WT spheroids. The LPP-KO spheroids adhering to the collagen gel responded with decreased contraction to potassium chloride. The relaxation response to caffeine and norepinephrine was also smaller in the LPP-KO spheroids than in their WT counterparts. The overexpression of zyxin in LPP-KO VSMCs resulted in a reversal to a more quiescent differentiated phenotype. In native VSMCs, i.e., in isolated perfused segments of the mesenteric artery (MA), the contractile responses of LPP-KO segments to potassium chloride, phenylephrine or endothelin-1 did not vary from those in isolated perfused WT segments. In contrast, the myogenic response of LPP-KO MA segments was significantly attenuated while zyxin-deficient MA segments displayed a normal myogenic response. We propose that LPP, which we found to be expressed solely in the medial layer of different arteries from adult mice, may play an important role in controlling the quiescent contractile phenotype of VSMCs.

Ectodomain Shedding by ADAM17 Increases the Release of Soluble CD40 from Human Endothelial Cells under Pro-Inflammatory Conditions.

BACKGROUND: Homozygosity for the C allele of the -1T>C single nucleotide polymorphism (SNP) of the CD40 gene (rs1883832) is associated with susceptibility to coronary heart disease (CHD), enhanced CD40 expression, and shedding. The disintegrin metalloprotease ADAM17 can cleave various cell surface proteins. This study investigates an association between ADAM17-mediated CD40 shedding and inflammation in CC genotype human endothelial cells. METHODS: Human umbilical vein endothelial cells (HUVEC) carrying the CC genotype were stimulated with soluble CD40 ligand (sCD40L) or tumor necrosis factor-α (TNFα). Messenger RNA and protein expression were determined with standard methods. Levels of high sensitive c-reactive protein (hs-CRP), interleukin-6 (IL-6), and sCD40 in plasma samples from patients with CHD were assessed using ELISA. RESULTS: ADAM17 surface abundance was elevated following stimulation with CD40L and TNFα just as its regulator iRhom2. Inhibition of ADAM17 prevented TNFα-induced sCD40 and soluble vascular cell adhesion molecule-1 release into the conditioned medium and reinforced CD40 surface abundance. Secondary to inhibition of ADAM17, stimulation with CD40L or TNFα upregulated monocyte chemoattractant protein-1 mRNA and protein. Levels of sCD40 and the inflammatory biomarkers hs-CRP and IL-6 were positively correlated in the plasma of patients with CHD. CONCLUSIONS: We provide a mechanism by which membrane-bound CD40 is shed from the endothelial cell surface by ADAM17, boosting sCD40 formation and limiting downstream CD40 signaling. Soluble CD40 may represent a robust biomarker for CHD, especially in conjunction with homozygosity for the C allele of the -1T>C SNP of the CD40 gene.

Apical and mechanistic effects of 6PPD-quinone on different life-stages of the fathead minnow (Pimephales promelas).

N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine-quinone (6PPD-quinone) is an emerging contaminant of concern that is generated through the environmental oxidation of the rubber tire anti-degradant 6PPD. Since the initial report of 6PPD-quinone being the cause of urban runoff mortality syndrome of Coho salmon, numerous species have been identified as either sensitive or insensitive to acute lethality caused by 6PPD-quinone. In sensitive species, acute lethality might be caused by uncoupling of mitochondrial respiration in gills. However, little is known about effects of 6PPD-quinone on insensitive species. Here we demonstrate that embryos of fathead minnows (Pimephales promelas) are insensitive to exposure to concentrations as great as 39.97 µg/L for 168 h, and adult fathead minnows are insensitive to exposure to concentrations as great as 9.4 µg/L for 96 h. A multi-omics approach using a targeted transcriptomics array, (EcoToxChips), and proton nuclear magnetic resonance (1H NMR) was used to assess responses of the transcriptomes and metabolomes of gills and livers from adult fathead minnows exposed to 6PPD-quinone for 96 h to begin to identify sublethal effects of 6PPD-quinone. There was little agreement between results of the EcoToxChip and metabolomics analyses, likely because genes present on the EcoToxChip were not representative of pathways suggested to be perturbed by metabolomic analysis. Changes in abundances of transcripts and metabolites in livers and gills suggest that disruption of one­carbon metabolism and induction of oxidative stress might be occurring in gills and livers, but that tissues differ in their sensitivity or responsiveness to 6PPD-quinone. Overall, several pathways impacted by 6PPD-quinone were identified as candidates for future studies of potential sublethal effects of this chemical.