Effects of environmental pollutants on calcium release and uptake by rat cortical microsomes

Hanna M. Dusza, Peter H. Cenijn, Jorke H. Kamstra, Remco H.S. Westerink, Pim E.G. Leonards, Timo Hamers

Research output: Contribution to JournalArticleAcademicpeer-review

Abstract

Dysregulation of neuronal intracellular Ca2+ homeostasis can play a crucial role in many neurotoxic effects, including impaired brain development and behavioral dysfunctions. This study examined 40 suspected neurotoxicants from different chemical classes for their capacity to alter Ca2+ release and uptake from rat cortical microsomes. First, ten suspected neurotoxicants have been tested using a well-established cuvette-based Ca2+ flux assay. Five out of ten compounds (TOCP, endosulfan, PCB-95, chlorpyrifos and BDE-49) showed a significant, concentration-dependent alteration of Ca2+ release and uptake in adult rat cortical microsomes. The original cuvette assay was downscaled and customized to a fast, higher throughput microplate method and the 40 suspected neurotoxicants were screened for their effects on intracellular Ca2+homeostasis. In decreasing order of potency, the 15 test compounds that showed the strongest alteration of Ca2+ levels in adult rat microsomes were TOCP, endosulfan, BDE-49, 6-OH-BDE-47, PCB-95, permethrin, alpha-cypermethrin, chlorpyrifos, bioallethrin, cypermethrin, RDP, DEHP, DBP, BDE-47, and PFOS. Results from co-exposure experiments with selective inhibitors suggested that for some compounds Ca2+ releasing effects could be attributed to RyR activation (PFOS, DBP, and DEHP) or to SERCA inhibition (a potential novel mechanism of action for all four tested pyrethroid insecticides). The effects of the two most potent compounds, endosulfan and TOCP, were not blocked by any of the inhibitors tested, indicating other possible mechanism of action. For all other potent test compounds, a combined effect on RyR, IP3R, and/or SERCA has been observed. PFOS and 6-OH-BDE-47 caused increased Ca2+ release from adult but not from neonatal rat brain microsomes, indicating age-dependent difference in susceptibility to these test compounds. The current study suggests that the neurotoxic potential of compounds belonging to different chemical classes could partly be attributed to the effects on intracellular Ca2+ release and uptake. Although further validation is required, the downscaled method developed in this study presents technical advance that could be used for the future screening of suspected intracellular Ca2+ disruptors.

Original languageEnglish
Pages (from-to)266-277
Number of pages12
JournalNeurotoxicology
Volume69
Early online date26 Jul 2018
DOIs
Publication statusPublished - Dec 2018

Fingerprint

Environmental Pollutants
Endosulfan
Microsomes
Rats
Diethylhexyl Phthalate
Calcium
Chlorpyrifos
Assays
Brain
Homeostasis
Permethrin
Pyrethrins
Insecticides
Screening
Chemical activation
Throughput
Fluxes
tri-o-cresyl phosphate
Experiments
2,2',4,5'-tetrabromodiphenyl ether

Keywords

  • Calcium homeostasis
  • Environmental pollutants
  • IP receptor
  • Microsomes
  • Neurotoxicity
  • Ryanodine receptor
  • SERCA

Cite this

@article{837b6827be674766b018693c840058b4,
title = "Effects of environmental pollutants on calcium release and uptake by rat cortical microsomes",
abstract = "Dysregulation of neuronal intracellular Ca2+ homeostasis can play a crucial role in many neurotoxic effects, including impaired brain development and behavioral dysfunctions. This study examined 40 suspected neurotoxicants from different chemical classes for their capacity to alter Ca2+ release and uptake from rat cortical microsomes. First, ten suspected neurotoxicants have been tested using a well-established cuvette-based Ca2+ flux assay. Five out of ten compounds (TOCP, endosulfan, PCB-95, chlorpyrifos and BDE-49) showed a significant, concentration-dependent alteration of Ca2+ release and uptake in adult rat cortical microsomes. The original cuvette assay was downscaled and customized to a fast, higher throughput microplate method and the 40 suspected neurotoxicants were screened for their effects on intracellular Ca2+homeostasis. In decreasing order of potency, the 15 test compounds that showed the strongest alteration of Ca2+ levels in adult rat microsomes were TOCP, endosulfan, BDE-49, 6-OH-BDE-47, PCB-95, permethrin, alpha-cypermethrin, chlorpyrifos, bioallethrin, cypermethrin, RDP, DEHP, DBP, BDE-47, and PFOS. Results from co-exposure experiments with selective inhibitors suggested that for some compounds Ca2+ releasing effects could be attributed to RyR activation (PFOS, DBP, and DEHP) or to SERCA inhibition (a potential novel mechanism of action for all four tested pyrethroid insecticides). The effects of the two most potent compounds, endosulfan and TOCP, were not blocked by any of the inhibitors tested, indicating other possible mechanism of action. For all other potent test compounds, a combined effect on RyR, IP3R, and/or SERCA has been observed. PFOS and 6-OH-BDE-47 caused increased Ca2+ release from adult but not from neonatal rat brain microsomes, indicating age-dependent difference in susceptibility to these test compounds. The current study suggests that the neurotoxic potential of compounds belonging to different chemical classes could partly be attributed to the effects on intracellular Ca2+ release and uptake. Although further validation is required, the downscaled method developed in this study presents technical advance that could be used for the future screening of suspected intracellular Ca2+ disruptors.",
keywords = "Calcium homeostasis, Environmental pollutants, IP receptor, Microsomes, Neurotoxicity, Ryanodine receptor, SERCA",
author = "Dusza, {Hanna M.} and Cenijn, {Peter H.} and Kamstra, {Jorke H.} and Westerink, {Remco H.S.} and Leonards, {Pim E.G.} and Timo Hamers",
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year = "2018",
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Effects of environmental pollutants on calcium release and uptake by rat cortical microsomes. / Dusza, Hanna M.; Cenijn, Peter H.; Kamstra, Jorke H.; Westerink, Remco H.S.; Leonards, Pim E.G.; Hamers, Timo.

In: Neurotoxicology, Vol. 69, 12.2018, p. 266-277.

Research output: Contribution to JournalArticleAcademicpeer-review

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T1 - Effects of environmental pollutants on calcium release and uptake by rat cortical microsomes

AU - Dusza, Hanna M.

AU - Cenijn, Peter H.

AU - Kamstra, Jorke H.

AU - Westerink, Remco H.S.

AU - Leonards, Pim E.G.

AU - Hamers, Timo

N1 - Copyright © 2018. Published by Elsevier B.V.

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N2 - Dysregulation of neuronal intracellular Ca2+ homeostasis can play a crucial role in many neurotoxic effects, including impaired brain development and behavioral dysfunctions. This study examined 40 suspected neurotoxicants from different chemical classes for their capacity to alter Ca2+ release and uptake from rat cortical microsomes. First, ten suspected neurotoxicants have been tested using a well-established cuvette-based Ca2+ flux assay. Five out of ten compounds (TOCP, endosulfan, PCB-95, chlorpyrifos and BDE-49) showed a significant, concentration-dependent alteration of Ca2+ release and uptake in adult rat cortical microsomes. The original cuvette assay was downscaled and customized to a fast, higher throughput microplate method and the 40 suspected neurotoxicants were screened for their effects on intracellular Ca2+homeostasis. In decreasing order of potency, the 15 test compounds that showed the strongest alteration of Ca2+ levels in adult rat microsomes were TOCP, endosulfan, BDE-49, 6-OH-BDE-47, PCB-95, permethrin, alpha-cypermethrin, chlorpyrifos, bioallethrin, cypermethrin, RDP, DEHP, DBP, BDE-47, and PFOS. Results from co-exposure experiments with selective inhibitors suggested that for some compounds Ca2+ releasing effects could be attributed to RyR activation (PFOS, DBP, and DEHP) or to SERCA inhibition (a potential novel mechanism of action for all four tested pyrethroid insecticides). The effects of the two most potent compounds, endosulfan and TOCP, were not blocked by any of the inhibitors tested, indicating other possible mechanism of action. For all other potent test compounds, a combined effect on RyR, IP3R, and/or SERCA has been observed. PFOS and 6-OH-BDE-47 caused increased Ca2+ release from adult but not from neonatal rat brain microsomes, indicating age-dependent difference in susceptibility to these test compounds. The current study suggests that the neurotoxic potential of compounds belonging to different chemical classes could partly be attributed to the effects on intracellular Ca2+ release and uptake. Although further validation is required, the downscaled method developed in this study presents technical advance that could be used for the future screening of suspected intracellular Ca2+ disruptors.

AB - Dysregulation of neuronal intracellular Ca2+ homeostasis can play a crucial role in many neurotoxic effects, including impaired brain development and behavioral dysfunctions. This study examined 40 suspected neurotoxicants from different chemical classes for their capacity to alter Ca2+ release and uptake from rat cortical microsomes. First, ten suspected neurotoxicants have been tested using a well-established cuvette-based Ca2+ flux assay. Five out of ten compounds (TOCP, endosulfan, PCB-95, chlorpyrifos and BDE-49) showed a significant, concentration-dependent alteration of Ca2+ release and uptake in adult rat cortical microsomes. The original cuvette assay was downscaled and customized to a fast, higher throughput microplate method and the 40 suspected neurotoxicants were screened for their effects on intracellular Ca2+homeostasis. In decreasing order of potency, the 15 test compounds that showed the strongest alteration of Ca2+ levels in adult rat microsomes were TOCP, endosulfan, BDE-49, 6-OH-BDE-47, PCB-95, permethrin, alpha-cypermethrin, chlorpyrifos, bioallethrin, cypermethrin, RDP, DEHP, DBP, BDE-47, and PFOS. Results from co-exposure experiments with selective inhibitors suggested that for some compounds Ca2+ releasing effects could be attributed to RyR activation (PFOS, DBP, and DEHP) or to SERCA inhibition (a potential novel mechanism of action for all four tested pyrethroid insecticides). The effects of the two most potent compounds, endosulfan and TOCP, were not blocked by any of the inhibitors tested, indicating other possible mechanism of action. For all other potent test compounds, a combined effect on RyR, IP3R, and/or SERCA has been observed. PFOS and 6-OH-BDE-47 caused increased Ca2+ release from adult but not from neonatal rat brain microsomes, indicating age-dependent difference in susceptibility to these test compounds. The current study suggests that the neurotoxic potential of compounds belonging to different chemical classes could partly be attributed to the effects on intracellular Ca2+ release and uptake. Although further validation is required, the downscaled method developed in this study presents technical advance that could be used for the future screening of suspected intracellular Ca2+ disruptors.

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