Effects of a human-based mixture of persistent organic pollutants on the in vivo exposed cerebellum and cerebellar neuronal cultures exposed in vitro

Hanne Friis Berntsen; Nur Duale; Cesilie Granum Bjørklund; Oscar Daniel Rangel-Huerta; Kine Dyrberg; Tim Hofer; Kirsten Eline Rakkestad; Gunn Østby; Ruth Halsne; Gudrun Boge; Ragnhild Elisabeth Paulsen; Oddvar Myhre; Erik Ropstad

doi:10.1016/j.envint.2020.106240

Effects of a human-based mixture of persistent organic pollutants on the in vivo exposed cerebellum and cerebellar neuronal cultures exposed in vitro

Environ Int. 2021 Jan:146:106240. doi: 10.1016/j.envint.2020.106240. Epub 2020 Nov 11.

Authors

Affiliations

¹ Department of Production Animal Clinical Sciences, NMBU-School of Veterinary Science, P.O. Box 369 sentrum, N-0102 Oslo, Norway; National Institute of Occupational Health, P.O. Box 5330 Majorstuen, 0304 Oslo, Norway. Electronic address: hanne.friis.berntsen@nmbu.no.
² Section of Molecular Toxicology, Norwegian Institute of Public Health, N-0403 Oslo, Norway. Electronic address: Nur.Duale@fhi.no.
³ Department of Production Animal Clinical Sciences, NMBU-School of Veterinary Science, P.O. Box 369 sentrum, N-0102 Oslo, Norway. Electronic address: cesilie@permakem.no.
⁴ Section of Chemistry and Toxinology, Norwegian Veterinary Institute, N-0454 Oslo, Norway. Electronic address: Oscar.Daniel.Rangel.Huerta@vetinst.no.
⁵ Department of Production Animal Clinical Sciences, NMBU-School of Veterinary Science, P.O. Box 369 sentrum, N-0102 Oslo, Norway. Electronic address: kine.dyrberg@tine.no.
⁶ Section of Toxicology and Risk Assessment, Norwegian Institute of Public Health, N-0403, Oslo, Norway. Electronic address: Tim.Hofer@fhi.no.
⁷ Section for Pharmacology and Pharmaceutical Biosciences, Department of Pharmacy, University of Oslo, P.O. Box 1072, Blindern, NO-0316 Oslo, Norway. Electronic address: KirstenEline.Rakkestad@vkm.no.
⁸ Department of Production Animal Clinical Sciences, NMBU-School of Veterinary Science, P.O. Box 369 sentrum, N-0102 Oslo, Norway. Electronic address: gunn.ostby@nmbu.no.
⁹ Department of Production Animal Clinical Sciences, NMBU-School of Veterinary Science, P.O. Box 369 sentrum, N-0102 Oslo, Norway. Electronic address: ruhals@ous-hf.no.
¹⁰ Department of Companion Animal Clinical Sciences, NMBU-School of Veterinary Science, P.O. Box 369 sentrum, N-0102 Oslo, Norway. Electronic address: Gudrun.Boge@legemiddelverket.no.
¹¹ Section for Pharmacology and Pharmaceutical Biosciences, Department of Pharmacy, University of Oslo, P.O. Box 1072, Blindern, NO-0316 Oslo, Norway. Electronic address: r.e.paulsen@farmasi.uio.no.
¹² Section of Toxicology and Risk Assessment, Norwegian Institute of Public Health, N-0403, Oslo, Norway. Electronic address: Oddvar.Myhre@fhi.no.
¹³ Department of Production Animal Clinical Sciences, NMBU-School of Veterinary Science, P.O. Box 369 sentrum, N-0102 Oslo, Norway. Electronic address: erik.ropstad@nmbu.no.

PMID: 33186814
DOI: 10.1016/j.envint.2020.106240

Abstract

Exposure to persistent organic pollutants (POPs), encompassing chlorinated (Cl), brominated (Br) and perfluoroalkyl acid (PFAA) compounds is associated with adverse neurobehaviour in humans and animals, and is observed to cause adverse effects in nerve cell cultures. Most studies focus on single POPs, whereas studies on effects of complex mixtures are limited. We examined the effects of a mixture of 29 persistent compounds (Cl + Br + PFAA, named Total mixture), as well as 6 sub-mixtures on in vitro exposed rat cerebellar granule neurons (CGNs). Protein expression studies of cerebella from in vivo exposed mice offspring were also conducted. The selection of chemicals for the POP mixture was based on compounds being prominent in food, breast milk or blood from the Scandinavian human population. The Total mixture and sub-mixtures containing PFAAs caused greater toxicity in rat CGNs than the single or combined Cl/Br sub-mixtures, with significant impact on viability from 500x human blood levels. The potencies for these mixtures based on LC₅₀ values were Br + PFAA mixture > Total mixture > Cl + PFAA mixture > PFAA mixture. These mixtures also accelerated induced lipid peroxidation. Protection by the competitive N-methyl-D-aspartate (NMDA) receptor antagonist 3-((R)-2-Carboxypiperazin-4-yl)-propyl-1-phosphonic acid (CPP) indicated involvement of the NMDA receptor in PFAA and Total mixture-, but not Cl mixture-induced toxicity. Gene-expression studies in rat CGNs using a sub-toxic and marginally toxic concentration ((0.4 nM-5.5 µM) 333x and (1 nM-8.2 µM) 500x human blood levels) of the mixtures, revealed differential expression of genes involved in apoptosis, oxidative stress, neurotransmission and cerebellar development, with more genes affected at the marginally toxic concentration. The two important neurodevelopmental markers Pax6 and Grin2b were downregulated at 500x human blood levels, accompanied by decreases in PAX6 and GluN2B protein levels, in cerebellum of offspring mice from mothers exposed to the Total mixture throughout pregnancy and lactation. In rat CGNs, the glutathione peroxidase gene Prdx6 and the regulatory transmembrane glycoprotein gene Sirpa were highly upregulated at both concentrations. In conclusion, our results support that early-life exposure to mixtures of POPs can cause adverse neurodevelopmental effects.

Keywords: Cerebellum; Gene expression; Human relevant mixtures; Neurodevelopment; Persistent organic pollutants; Redox signalling.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Animals
Cerebellum
Environmental Pollutants* / toxicity
Female
Humans
Mice
Neurons
Oxidative Stress
Persistent Organic Pollutants*
Rats

Substances

Environmental Pollutants