自闭症患者小脑中海藻糖-3-磷酸合成酶和抗氧化防御能力受损：谷胱甘肽相关酶的活性和蛋白表达改变。

Impaired synthesis and antioxidant defense of glutathione in the cerebellum of autistic subjects: alterations in the activities and protein expression of glutathione-related enzymes.

机构信息

NYS Institute for Basic Research in Developmental Disabilities, 1050 Forest Hill Road, Staten Island, NY 10314, USA.

出版信息

Free Radic Biol Med. 2013 Dec;65:488-496. doi: 10.1016/j.freeradbiomed.2013.07.021. Epub 2013 Jul 26.

DOI:10.1016/j.freeradbiomed.2013.07.021

Abstract

Autism is a neurodevelopmental disorder associated with social deficits and behavioral abnormalities. Recent evidence in autism suggests a deficit in glutathione (GSH), a major endogenous antioxidant. It is not known whether the synthesis, consumption, and/or regeneration of GSH is affected in autism. In the cerebellum tissues from autism (n=10) and age-matched control subjects (n=10), the activities of GSH-related enzymes glutathione peroxidase (GPx), glutathione-S-transferase (GST), glutathione reductase (GR), and glutamate cysteine ligase (GCL) involved in antioxidant defense, detoxification, GSH regeneration, and synthesis, respectively, were analyzed. GCL is a rate-limiting enzyme for GSH synthesis, and the relationship between its activity and the protein expression of its catalytic subunit GCLC and its modulatory subunit GCLM was also compared between the autistic and the control groups. Results showed that the activities of GPx and GST were significantly decreased in autism compared to that of the control group (P<0.05). Although there was no significant difference in GR activity between autism and control groups, 40% of autistic subjects showed lower GR activity than 95% confidence interval (CI) of the control group. GCL activity was also significantly reduced by 38.7% in the autistic group compared to the control group (P=0.023), and 8 of 10 autistic subjects had values below 95% CI of the control group. The ratio of protein levels of GCLC to GCLM in the autism group was significantly higher than that of the control group (P=0.022), and GCLM protein levels were reduced by 37.3% in the autistic group compared to the control group. A positive strong correlation was observed between GCL activity and protein levels of GCLM (r=0.887) and GCLC (r=0.799) subunits in control subjects but not in autistic subjects, suggesting that regulation of GCL activity is affected in autism. These results suggest that enzymes involved in GSH homeostasis have impaired activities in the cerebellum in autism, and lower GCL activity in autism may be related to decreased protein expression of GCLM.

摘要

自闭症是一种与社交缺陷和行为异常相关的神经发育障碍。最近的自闭症研究证据表明，谷胱甘肽（GSH）存在缺陷，GSH 是一种主要的内源性抗氧化剂。目前尚不清楚自闭症是否会影响 GSH 的合成、消耗和/或再生。在自闭症（n=10）和年龄匹配的对照组（n=10）的小脑组织中，分析了与抗氧化防御、解毒、GSH 再生和合成分别相关的 GSH 相关酶谷胱甘肽过氧化物酶（GPx）、谷胱甘肽-S-转移酶（GST）、谷胱甘肽还原酶（GR）和谷氨酸半胱氨酸连接酶（GCL）的活性。GCL 是 GSH 合成的限速酶，还比较了自闭症组和对照组之间其活性与其催化亚基 GCLC 和调节亚基 GCLM 的蛋白表达之间的关系。结果表明，与对照组相比，自闭症组中 GPx 和 GST 的活性显著降低（P<0.05）。尽管自闭症组和对照组之间的 GR 活性没有显著差异，但 40%的自闭症患者的 GR 活性低于对照组 95%置信区间（CI）。自闭症组的 GCL 活性也比对照组降低了 38.7%（P=0.023），10 名自闭症患者中有 8 名的数值低于对照组的 95%CI。自闭症组 GCLC 与 GCLM 的蛋白水平比值明显高于对照组（P=0.022），与对照组相比，自闭症组的 GCLM 蛋白水平降低了 37.3%。在对照组中，GCL 活性与 GCLM（r=0.887）和 GCLC（r=0.799）亚基的蛋白水平之间存在正强相关性，但在自闭症患者中没有，这表明自闭症患者的 GCL 活性受到调节。这些结果表明，GSH 动态平衡中涉及的酶在自闭症患者的小脑中有受损的活性，自闭症患者中较低的 GCL 活性可能与 GCLM 的蛋白表达降低有关。