Project description:Per- and polyfluoroalkyl substances (PFAS) are a very large (thousands of chemicals) category; these substances have important industrial and consumer product applications. PFAS are highly persistent in the environment, and some are known to pose human health hazard. Regulatory agencies worldwide are considering restrictions and outright bans of PFAS; however, little data exists to make informed decisions. Therefore, a prioritization strategy is urgently needed for evaluation of potential hazards of PFAS. Structure-based grouping could expedite selection of PFAS for testing; still, the hypothesis that structure-effect relationships exist requires confirmation. We tested 26 structurally diverse PFAS from 8 groups in two human cell types from organs that are thought to be targets for PFAS. We used human induced pluripotent stem cell-derived hepatocytes and cardiomyocytes and tested concentration-response effects on both cell function and gene expression. Few phenotypic effects were observed in hepatocytes, but negative chronotropy was observed for 8 of 26 PFAS. Substance- and cell-dependent transcriptomic changes were more pronounced; however, little evidence of group-specific effects was observed. In hepatocytes, we found up-regulation of stress-related and extracellular matrix organization pathways, and down-regulation of fat metabolism. In cardiomyocytes, contractility-related pathways were most affected. Using these data, we derived phenotypic and transcriptomic point of departure estimates and compared them to predicted PFAS exposures. The conservative estimates for bioactivity and exposure were used to derive margin-of-exposure (MOE) for each PFAS. We found that most (23 of 26) PFAS had MOE>1. Overall, our data suggests that chemical structure-based grouping of PFAS may not be an appropriate strategy to predict their biological effects. This means that testing of the individual PFAS would be needed for confident decision-making. Our proposed strategy of using two human cell types and considering both phenotypic and transcriptomic effects, combined with dose-response analysis, may be used for prioritization of PFAS.
Project description:Per- and polyfluoroalkyl substances (PFAS) are a very large (thousands of chemicals) category; these substances have important industrial and consumer product applications. PFAS are highly persistent in the environment, and some are known to pose human health hazard. Regulatory agencies worldwide are considering restrictions and outright bans of PFAS; however, little data exists to make informed decisions. Therefore, a prioritization strategy is urgently needed for evaluation of potential hazards of PFAS. Structure-based grouping could expedite selection of PFAS for testing; still, the hypothesis that structure-effect relationships exist requires confirmation. We tested 26 structurally diverse PFAS from 8 groups in two human cell types from organs that are thought to be targets for PFAS. We used human induced pluripotent stem cell-derived hepatocytes and cardiomyocytes and tested concentration-response effects on both cell function and gene expression. Few phenotypic effects were observed in hepatocytes, but negative chronotropy was observed for 8 of 26 PFAS. Substance- and cell-dependent transcriptomic changes were more pronounced; however, little evidence of group-specific effects was observed. In hepatocytes, we found up-regulation of stress-related and extracellular matrix organization pathways, and down-regulation of fat metabolism. In cardiomyocytes, contractility-related pathways were most affected. Using these data, we derived phenotypic and transcriptomic point of departure estimates and compared them to predicted PFAS exposures. The conservative estimates for bioactivity and exposure were used to derive margin-of-exposure (MOE) for each PFAS. We found that most (23 of 26) PFAS had MOE>1. Overall, our data suggests that chemical structure-based grouping of PFAS may not be an appropriate strategy to predict their biological effects. This means that testing of the individual PFAS would be needed for confident decision-making. Our proposed strategy of using two human cell types and considering both phenotypic and transcriptomic effects, combined with dose-response analysis, may be used for prioritization of PFAS.
Project description:Per- and polyfluoroalkyl substances (PFAS) are environmental contaminants of concern due to their persistence and potential adverse health effects. Epidemiological studies have linked PFAS with an increased risk of uterine diseases including fibroids however, the mechanisms involved remain to be elucidated. This study investigated the effects of individual PFAS, including long-chain “legacy” PFAS [perfluorooctanoic acid (PFOA), perfluorooctanesulfonic acid (PFOS)] and short-chain “alternative” PFAS compounds [undecafluoro-2-methyl-3-oxahexanoic acid (GENX/HFPO-DA), perfluorobutanesulfonic acid (PFBS)], as well as a mixture of these chemicals on the function and transcriptome of an immortalized human myometrial cell line (UT-TERT). UT-TERT cells exposed to individual PFAS displayed increased cell viability and proliferation. Flow cytometry analysis revealed that PFOS and the PFAS mixture altered cell cycle progression. Migration assays demonstrated that PFOS and the PFAS mixture significantly enhanced UT-TERT cell migration. Gap junction intercellular communication (GJIC) was impaired following PFOA, PFBS, and PFAS mixture exposure, indicating potential disruptions in cell-to-cell communication within the uterine environment. Transcriptomic analysis using RNA-seq identified substantial changes in gene expression after exposure to environmentally relevant levels of individual PFAS and PFAS mixture. Pathway analysis revealed common molecular pathways associated with PFAS exposure, including Cell-to-Cell Signaling, Lipid Metabolism, and Cell Death and Survival, while other pathways were unique to specific PFAS. These findings highlight the multifaceted effects of PFAS on myometrial cells, providing insights into the potential mechanisms underlying PFAS-associated health risks. Further research is necessary to elucidate the long-term implications of PFAS exposure on uterine function and overall reproductive health.
Project description:Per- and polyfluoroalkyl substances (PFAS) are some of the most prominent organic contaminants in human blood that have the potential to disrupt biological processes and pathways in the liver. Although the toxicological implications from human exposure to perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA) are well established, data on other, lesser-understood PFAS are limited. A challenge for regulatory authorities is to determine acceptable levels of human exposure to large, diverse classes of environmental contaminants. New approach methodologies (NAMs) that apply bioinformatics tools to interpret biological data are being increasingly considered to inform risk assessment when traditional toxicology methodologies are not amenable. The aim of the current investigation was to identify the biological responses relevant to PFAS mode of action as the concentration (benchmark dose) that these effects take place in order to utililze this information to inform/facilitate read-across for risk assessment of data-poor PFAS. A TempO-Seq platform (BioSpyder) measured gene expression changes in human liver microtissues (i.e., spheroids) after 1-day and 10-day exposures to increasing concentrations of PFAS. A bioinformatics framework was applied to 23 PFAS sub-classed into carboxylates (PFCAs), sulfonates (PFSAs), or PFAS precursors that were analyzed for the total altered transcripts, the concentration where effects take place, and identifying target genes of interest. Both PFCAs and PFSAs exhibited a trend toward increased transcriptional changes with carbon chain-length. Specifically, longer-chain compounds (7 to 10 carbons) were more likely to surpass liver-toxic transcriptomic thresholds established from previous studies than shorter chain PFAS. Longer-chain PFAS were also more potent, inducing transcriptional effects at lower concentrations. However, PFOS was the most potent PFAS and of all precursors, only PFOSA (a PFOS precursor) induced a response. The combined high-throughput transcriptomic and bioinformatics analyses revealed the capability of NAMs to assess the effects of PFAS in liver microtissues; such data improves our understanding of PFAS-related effects in humans and facilitates the use of read-across in human health risk assessment for other data-poor chemicals.
Project description:Perfluoroalkyl substances (PFAS) are a group of synthetic chemicals that are resistant to biodegradation and are environmentally persistent. PFAS are found in many consumer products including non-stick cookware, food packaging materials, upholstery, and personal care products. Accordingly, PFAS are a major source of water and soil contamination. Although use of many PFAS have been phased out, they continue to be detected in human and animal fluids, including human follicular fluid. This study investigated the effects of an environmentally relevant PFAS mixture [perfluorooctanoic acid (PFOA), perfluorooctanesulfonic acid (PFOS), perfluorohexanesulfonic acid (PFHxS)] on the transcriptome and function of human granulosa cells (hGCs). PFOA, PFOS, and PFHxS were detected in 100% of follicle fluid samples. Increased cell proliferation was observed in hGCs treated with the PFAS mixture with no impacts on cellular apoptosis. The PFAS mixture also altered steroid hormone synthesis, increasing both FSH-stimulated and basal progesterone secretion and concomitant upregulation of STAR protein. RNA sequencing revealed inherent differences in transcriptomic profiles in hGCs after PFAS exposure. This study demonstrates functional and transcriptomic changes in hGCs after exposure to a PFAS mixture, improving our knowledge about the impacts of PFAS exposures and female reproductive health. These findings suggest that PFAS compounds have the potential to disrupt normal granulosa cell function with possible long-term consequences on overall reproductive health.
Project description:The use of aqueous film-forming foams (AFFF) at fire-training areas (FTAs) has introduced into ground- and surface waters a complex mixture of per- and poly-fluorinated alkyl substances (PFAS). The toxicity of environmental PFAS mixtures to wildlife is not well understood and presents a knowledge gap that limits accurate risk assessment. To evaluate reproductive biomarker responses to complex environmental PFAS mixtures, we conducted a series of on-site experiments using flow-through mobile laboratories exposing fish to groundwater impacted by a legacy FTA and an adjacent reference site A 60K fathead minnow microarray was used to quantify gene expression patterns in the testis and liver of fish exposed to water from Fire Training Area 1 and 2 relative to a reference site.
Project description:The use of aqueous film-forming foams (AFFF) at fire-training areas (FTAs) has introduced into ground- and surface waters a complex mixture of per- and poly-fluorinated alkyl substances (PFAS). The toxicity of environmental PFAS mixtures to wildlife is not well understood and presents a knowledge gap that limits accurate risk assessment. To evaluate reproductive biomarker responses to complex environmental PFAS mixtures, we conducted a series of on-site experiments using flow-through mobile laboratories exposing fish to groundwater impacted by a legacy FTA and an adjacent reference site A 60K fathead minnow microarray was used to quantify gene expression patterns in the testis and liver of fish exposed to water from Fire Training Area 1 and 2 relative to a reference site.