Manganese induces oxidative impairment in cultured rat astrocytes

Dejan Milatovic, Zhaobao Yin, Ramesh C. Gupta, Marta Sidoryk, Jan Albrecht, Judy L. Aschner, Michael Aschner

Research output: Contribution to journalArticle

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Abstract

Excessive free radical formation has been implicated as a causative factor in neurotoxic damage associated with exposures to a variety of metals, including manganese (Mn). It is well established that Mn accumulates in astrocytes, affecting their ability to indirectly induce and/or exacerbate neuronal dysfunction. The present study examined the effects of Mn treatment on the following endpoints in primary astrocyte cultures: (1) oxidative injury, (2) alterations in high-energy phosphate (adenosine 5′-triphosphate, ATP) levels, (3) mitochondrial inner membrane potential, and (4) glutamine uptake and the expression of glutamine transporters. We quantified astrocyte cerebral oxidative damage by measuring F2-isoprostanes (F2-IsoPs) using stable isotope dilution methods followed by gas chromatography-mass spectrometry with selective ion monitoring. Our data showed a significant (p < 0.01) elevation in F2-IsoPs levels at 2 h following exposure to Mn (100μM, 500μM, or 1mM). Consistent with this observation, Mn induced a concentration-dependent reduction in ATP and the inner mitochondrial membrane potential (ΔΨm), measured by the high pressure liquid chromatography method and the potentiometric dye, tetramethyl rhodamine ethyl ester, respectively. Moreover, 30 min of pretreatment with Mn (100μM, 500μM, or 1mM) inhibited the net uptake of glutamine (GLN) (3H-glutamine) measured at 1 and 5 min. Expression of the messenger RNA coding the GLN transporters, SNAT3/SN1 and SNAT1, was inhibited after 100 and 500μM Mn treatment for 24 h. Our results demonstrate that induction of oxidative stress, associated mitochondrial dysfunction, and alterations in GLN/glutamate cycling in astrocytes represent key mechanisms by which Mn exerts its neurotoxicity.

Original languageEnglish (US)
Pages (from-to)198-205
Number of pages8
JournalToxicological Sciences
Volume98
Issue number1
DOIs
StatePublished - Jul 2007
Externally publishedYes

Fingerprint

Manganese
Astrocytes
Rats
Glutamine
F2-Isoprostanes
Mitochondrial Membrane Potential
Adenosine Triphosphate
High pressure liquid chromatography
Membranes
Oxidative stress
Mitochondrial Membranes
Adenosine Monophosphate
Isotopes
Gas chromatography
Adenosine
Gas Chromatography-Mass Spectrometry
Dilution
Free Radicals
Mass spectrometry
Glutamic Acid

Keywords

  • ΔΨ
  • Astrocyte
  • ATP
  • F-isoprostanes
  • Glutamine
  • Manganese
  • Mitochondria

ASJC Scopus subject areas

  • Toxicology

Cite this

Milatovic, D., Yin, Z., Gupta, R. C., Sidoryk, M., Albrecht, J., Aschner, J. L., & Aschner, M. (2007). Manganese induces oxidative impairment in cultured rat astrocytes. Toxicological Sciences, 98(1), 198-205. https://doi.org/10.1093/toxsci/kfm095

Manganese induces oxidative impairment in cultured rat astrocytes. / Milatovic, Dejan; Yin, Zhaobao; Gupta, Ramesh C.; Sidoryk, Marta; Albrecht, Jan; Aschner, Judy L.; Aschner, Michael.

In: Toxicological Sciences, Vol. 98, No. 1, 07.2007, p. 198-205.

Research output: Contribution to journalArticle

Milatovic, D, Yin, Z, Gupta, RC, Sidoryk, M, Albrecht, J, Aschner, JL & Aschner, M 2007, 'Manganese induces oxidative impairment in cultured rat astrocytes', Toxicological Sciences, vol. 98, no. 1, pp. 198-205. https://doi.org/10.1093/toxsci/kfm095
Milatovic D, Yin Z, Gupta RC, Sidoryk M, Albrecht J, Aschner JL et al. Manganese induces oxidative impairment in cultured rat astrocytes. Toxicological Sciences. 2007 Jul;98(1):198-205. https://doi.org/10.1093/toxsci/kfm095
Milatovic, Dejan ; Yin, Zhaobao ; Gupta, Ramesh C. ; Sidoryk, Marta ; Albrecht, Jan ; Aschner, Judy L. ; Aschner, Michael. / Manganese induces oxidative impairment in cultured rat astrocytes. In: Toxicological Sciences. 2007 ; Vol. 98, No. 1. pp. 198-205.
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