Li Tianfu, Ren Gaoying, Lusardi Theresa, Wilz Andrew, Lan Jing Q, Iwasato Takuji, Itohara Shigeyoshi, Simon Roger P, Boison Detlev
Robert S. Dow Neurobiology Laboratories, Legacy Clinical Research, Portland, Oregon 97232, USA.
J Clin Invest. 2008 Feb;118(2):571-82. doi: 10.1172/JCI33737.
Astrogliosis is a pathological hallmark of the epileptic brain. The identification of mechanisms that link astrogliosis to neuronal dysfunction in epilepsy may provide new avenues for therapeutic intervention. Here we show that astrocyte-expressed adenosine kinase (ADK), a key negative regulator of the brain inhibitory molecule adenosine, is a potential predictor and modulator of epileptogenesis. In a mouse model of focal epileptogenesis, in which astrogliosis is restricted to the CA3 region of the hippocampus, we demonstrate that upregulation of ADK and spontaneous focal electroencephalographic seizures were both restricted to the affected CA3. Furthermore, spontaneous seizures in CA3 were mimicked in transgenic mice by overexpression of ADK in this brain region, implying that overexpression of ADK without astrogliosis is sufficient to cause seizures. Conversely, after pharmacological induction of an otherwise epileptogenesis-precipitating acute brain injury, transgenic mice with reduced forebrain ADK were resistant to subsequent epileptogenesis. Likewise, ADK-deficient ES cell-derived brain implants suppressed astrogliosis, upregulation of ADK, and spontaneous seizures in WT mice when implanted after the epileptogenesis-precipitating brain injury. Our findings suggest that astrocyte-based ADK provides a critical link between astrogliosis and neuronal dysfunction in epilepsy.
星形胶质细胞增生是癫痫脑的一个病理标志。确定将星形胶质细胞增生与癫痫中神经元功能障碍联系起来的机制,可能为治疗干预提供新途径。在此我们表明,星形胶质细胞表达的腺苷激酶(ADK)是脑抑制分子腺苷的关键负调节因子,是癫痫发生的潜在预测因子和调节因子。在局灶性癫痫发生的小鼠模型中,星形胶质细胞增生局限于海马体的CA3区域,我们证明ADK的上调和自发性局灶性脑电图癫痫发作都局限于受影响的CA3区域。此外,通过在该脑区过表达ADK,在转基因小鼠中模拟了CA3区域的自发性癫痫发作,这意味着在没有星形胶质细胞增生的情况下ADK的过表达足以引发癫痫发作。相反,在药理学诱导原本会引发癫痫发生的急性脑损伤后,前脑ADK减少的转基因小鼠对随后的癫痫发生具有抗性。同样,在引发癫痫发生的脑损伤后植入ADK缺陷的胚胎干细胞衍生的脑植入物,可抑制野生型小鼠的星形胶质细胞增生、ADK的上调和自发性癫痫发作。我们的研究结果表明,基于星形胶质细胞的ADK在癫痫中星形胶质细胞增生和神经元功能障碍之间提供了关键联系。