Zemlyak Ilona, Nimon Vitaliy, Brooke Sheila, Moore Tejaswini, McLaughlin John, Sapolsky Robert
Dept. of Biological Sciences, Stanford University, Gilbert Lab, MC 5020, Stanford, CA 94305-5020, USA.
Brain Res. 2006 May 9;1088(1):12-8. doi: 10.1016/j.brainres.2006.02.109. Epub 2006 Apr 21.
Neuronal death following necrotic insults involves the generation of reactive oxygen species (ROS). We investigated the effects of antioxidant gene therapy on ROS accumulation after exposure to either sodium cyanide, kainic acid or oxygen glucose deprivation (OGD). Specifically, we generated herpes simplex virus-1 amplicon vector expressing the gene for the antioxidant enzyme CuZnSOD. Overexpression of this gene in primary hippocampal cultures resulted in increased enzymatic activity of the corresponding protein. CuZnSOD significantly protected hippocampal neurons against sodium cyanide insult and the subsequent lipid peroxidation. However, it did not protect against OGD- or kainic-acid-induced toxicity. Moreover, CuZnSOD significantly worsened the toxicity, hydrogen peroxide accumulation and lipid peroxidation induced by kainic acid. As a possible explanation for this surprising worsening, CuZnSOD overexpression increased glutathione peroxidase activity in the presence of sodium cyanide but had no effect on catalase or glutathione peroxidase activity in the presence of kainic acid. Thus, cells were unlikely to be able to detoxify the excess hydrogen peroxide produced as a result of the CuZnSOD overexpression. These studies can be viewed as a cautionary note concerning gene therapy intervention against necrotic insults.
坏死性损伤后的神经元死亡涉及活性氧（ROS）的产生。我们研究了抗氧化基因治疗对暴露于氰化钠、海藻酸或氧糖剥夺（OGD）后ROS积累的影响。具体而言，我们构建了表达抗氧化酶铜锌超氧化物歧化酶（CuZnSOD）基因的单纯疱疹病毒1型扩增载体。该基因在原代海马培养物中的过表达导致相应蛋白质的酶活性增加。CuZnSOD显著保护海马神经元免受氰化钠损伤及随后的脂质过氧化。然而，它不能保护细胞免受OGD或海藻酸诱导的毒性。此外，CuZnSOD显著加重了海藻酸诱导的毒性、过氧化氢积累和脂质过氧化。作为对这种惊人恶化的一种可能解释，CuZnSOD过表达在存在氰化钠的情况下增加了谷胱甘肽过氧化物酶活性，但在存在海藻酸的情况下对过氧化氢酶或谷胱甘肽过氧化物酶活性没有影响。因此，细胞不太可能能够清除因CuZnSOD过表达而产生的过量过氧化氢。这些研究可被视为关于针对坏死性损伤的基因治疗干预的一个警示。
