ToxSci Advance Access published online on October 31, 2007
Toxicological Sciences, doi:10.1093/toxsci/kfm267
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Mitochondrial-mediated apoptosis in neural stem cells exposed to manganese

* Institute of Environmental Medicine, Division of Toxicology and Neurotoxicology, Karolinska Institutet, SE-171 77 Stockholm, Sweden
Corresponding author: Sandra Ceccatelli, E-mail: sandra.ceccatelli{at}ki.se, Tel: +46 8 52487586, Fax: +46 8 329041
Received August 16, 2007; revision received October 18, 2007; accepted October 19, 2007
| Abstract |
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Manganese is an essential nutrient for humans that has to be maintained at proper levels for normal brain functioning. However, manganese also acts as a toxicant to the brain and several studies have linked exposure to excessive manganese to neurotoxicity in adults. A recent report has suggested that ingesting high doses of manganese via drinking water can impede intellectual functions in children. It is known that during development the nervous system is particularly vulnerable to different types of injuries and toxicants. Neural stem cells (NSCs) play an essential role in both the developing nervous system and the adult brain where the capacity for self-renewal may be important. In the present study we have used NSCs to investigate the molecular mechanisms involved in manganese developmental neurotoxicity. The results show that primary cultures of rat embryonic cortical NSC (cNSCs) as well as the murine-derived multipotent neural stem cell line C17.2 undergo apoptotic cell death via a mitochondrial-mediated pathway in response to manganese. Exposed cells exhibit typical apoptotic features, such as chromatin condensation and cell shrinkage, mitochondrial cytochrome c release, activation of caspase-3, and caspase-specific cleavage of the endogenous substrate PARP. In addition, our data also show that ROS formation play a role in the onset of manganese toxicity in NSCs.
Key Words: C17.2; cell death; MnCl2; ROS.
Author e-mail addresses: christoffer.tamm{at}ki.se, farideh.sabri{at}ki.se, sandra.ceccatelli{at}ki.se