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Collier GE, Lavado R. An in-depth examination of Per- and Polyfluoroalkyl (PFAS) effects on transporters, with emphasis on the ABC superfamily: A critical review. Toxicology 2024; 508:153901. [PMID: 39094918 DOI: 10.1016/j.tox.2024.153901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2024] [Revised: 07/27/2024] [Accepted: 07/29/2024] [Indexed: 08/04/2024]
Abstract
Per- and polyfluoroalkyl (PFAS) substances are a type of chemical compound unique for their multiple carbon-fluorine bonds, imbuing them with strength and environmental permanence. While legacy substances have been phased out due to human health risks, short-chain and alternative PFAS remain omnipresent. However, a detailed explanation for the pathways through which PFAS interact on a cellular and molecular level is still largely unknown, and the human health effects remain mechanistically unexplained. Of particular interest when focusing on this topic are the interactions between these exogenous chemicals and plasma and membrane proteins. Such proteins include serum albumin which can transport PFAS throughout the body, solute carrier proteins (SLC) and ATP binding cassette (ABC) transporters which are able to move PFAS into and out of cells, and proteins and nuclear receptors which interact with PFAS intracellularly. ABC transporters as a family have little available human data despite being responsible for the export of endogenous substances and drugs throughout the body. The multifactorial regulation of these crucial transporters is affected directly and indirectly by PFAS. Changes, which can include alterations to membrane transport activity and differences in protein expression, vary greatly depending on the specific PFAS and protein of interest. Together, the myriad of changes caused by understudied PFAS exposure to a class of understudied proteins crucial to cellular function and drug treatments has not been fully explored regarding human health and presents room for further exploration. This critical work aims to provide a novel framework of existing human data on PFAS and ABC transporters, allowing for future advancement and investigation into human transporter activity, mechanisms of regulation, and interactions with emerging contaminants.
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Affiliation(s)
- Gracen E Collier
- Department of Environmental Science, Baylor University, Waco, TX 76798, United States
| | - Ramon Lavado
- Department of Environmental Science, Baylor University, Waco, TX 76798, United States.
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Carberry CK, Bangma J, Koval L, Keshava D, Hartwell HJ, Sokolsky M, Fry RC, Rager JE. Extracellular Vesicles altered by a Per- and Polyfluoroalkyl Substance Mixture: In Vitro Dose-Dependent Release, Chemical Content, and MicroRNA Signatures involved in Liver Health. Toxicol Sci 2023; 197:kfad108. [PMID: 37851381 PMCID: PMC10823775 DOI: 10.1093/toxsci/kfad108] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2023] Open
Abstract
Per- and polyfluoroalkyl substances (PFAS) have emerged as high priority contaminants due to their ubiquity and pervasiveness in the environment. Numerous PFAS co-occur across sources of drinking water, including areas of North Carolina (NC) with some detected concentrations above the Environmental Protection Agency's health advisory levels. While evidence demonstrates PFAS exposure induces harmful effects in the liver, the involvement of extracellular vesicles (EVs) as potential mediators of these effects has yet to be evaluated. This study set out to evaluate the hypothesis that PFAS mixtures induce dose-dependent release of EVs from liver cells, with exposures causing differential loading of microRNAs (miRNAs) and PFAS chemical signatures. To test this hypothesis, a defined PFAS mixture was prioritized utilizing data collected by the NC PFAS Testing Network. This mixture contained three substances, PFOS, PFOA, and PFHxA, selected based upon co-occurrence patterns and the inclusion of both short-chain (PFHxA) and long-chain (PFOA and PFOS) substances. HepG2 liver cells were exposed to equimolar PFAS, and secreted EVs were isolated from conditioned media and characterized for count and molecular content. Exposures induced a dose-dependent release of EVs carrying miRNAs that were differentially loaded upon exposure. These altered miRNA signatures were predicted to target mRNA pathways involved in hepatic fibrosis and cancer. Chemical concentrations of PFOS, PFOA, and PFHxA were also detected in both parent HepG2 cells and their released EVs, specifically within a 15-fold range after normalizing for protein content. This study therefore established EVs as novel biological responders and measurable endpoints for evaluating PFAS-induced toxicity.
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Affiliation(s)
- Celeste K Carberry
- The Institute for Environmental Health Solutions, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Jacqueline Bangma
- Center for Environmental Measurement and Modeling, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina 27711, USA
| | - Lauren Koval
- The Institute for Environmental Health Solutions, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Deepak Keshava
- The Institute for Environmental Health Solutions, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Hadley J Hartwell
- The Institute for Environmental Health Solutions, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Marina Sokolsky
- Center for Nanotechnology in Drug Delivery, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Rebecca C Fry
- The Institute for Environmental Health Solutions, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
- School of Medicine, Curriculum in Toxicology and Environmental Medicine, University of North Carolina, Chapel Hill, North Carolina, USA
| | - Julia E Rager
- The Institute for Environmental Health Solutions, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
- Department of Environmental Sciences and Engineering, Gillings School of Global Public Health, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
- School of Medicine, Curriculum in Toxicology and Environmental Medicine, University of North Carolina, Chapel Hill, North Carolina, USA
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