| 摘要: | 我們曾經針對抗癲癇藥物之代謝進行藥物基因學研究，發現CYP2C9/CYP2C19之基因多型性在藥物代謝上扮演重要的角色。此研究成果已發表於國際期刊 (Ther Drug Monit. 2004;26:534-540)，並獲得基因學大師，David B Goldstein (director of population genetics of Duke University, 發表許多文章於Nature genetics、Am J Hum Gene)，高度的重視，主動且積極地聯絡；我們已經在SCN1A基因進行了良好的合作，研究成果已發表於國際期刊 (Pharmacogenet Genomics. 2006;16:721-726)；在難治型癲癇症之基因醫學研究方面，我們已針對ABCB1與NR1I2基因多型性與癲癇症療效之相關性進行研究，結果也均已發表於國際基因學期刊 (Pharmacogenomics 2005;6:411-417; Pharmacogenomics 2007;8:1151-1158)，目前正在進行進一步之蛋白質功能分析研究，以探討難治型癲癇症之機轉與ABCB1基因多型性位點對 Pgp蛋白質功能之影響。難治型癲癇症是癲癇症治療中的一個主要的難題。造成難治型癲癇症的機轉目前尚未完全了解，但是經由轉運子使腦中有效藥物濃度降低是一個可能的因素。P醣蛋白是血腦障蔽上的首要成員，因其位於表面，表現量高且其運輸藥物之能力強。所以，改變P醣蛋白之活性可能可使進入中樞神經作用之藥物增多。已有研究顯示，在小鼠腦部微血管中，endothelin-1 (ET-1)，經由ET receptor，NO synthase，及 protein kinase C，快速且可回腹地降低P醣蛋白運輸的功能。由此可推論，NO可能扮演調節P醣蛋白運輸的功能。B NO是一個微小的訊息傳遞分子，與許多細胞功能相關，包括生長，分化及細胞凋亡。在細胞中，有多因素會刺激NO的產生，如：bacterial lipopolysaccharide, cytokines, oxidative stress, 及 statins。而YC-1 [3-(5-hydroxymethyl-2-furyl)-1-benzyl-indazole]，一個新的合成物，也會使NO對酵素的敏感度增加上百倍。既然NO已被證實可能與P醣蛋白運輸的功能相關，YC-1與statins也可能參與P醣蛋白運輸功能的調控。綜合上述，本研究即將要進行的研究目標是(1) 探討YC-1對P醣蛋白運輸功能的影響；(2) 探討YC-1調控P醣蛋白運輸功能之可能機轉；(3) 探討YC-1調控P醣蛋白運輸功能是否受到基因多型性之影響及可能之結合位置；(4) 探討statins對P醣蛋白運輸功能的影響；(5) 探討statins調控P醣蛋白運輸功能之可能機轉；(6) 探討statins調控P醣蛋白運輸功能是否受到基因多型性之影響及可能之結合位置；(7) 探討YC-1及statins對抗癲癇藥進入血腦障蔽之影響。完成本研究後，對於P醣蛋白在難治型癲癇症所扮演的腳色將更加了解；不僅對臨床醫師提供了有用的資訊，並且也提供了扭轉多重抗藥性之可能藥物。 P-glycoprotein Genetic susceptibility loci Multidrug-resistant epilepsyNO modulatorsYC-1 Statins Pathway/Mechanism Binding site BBB model The flow chart of the study
We have studied the pharmacogenetics of drug metabolic enzymes, CYP2C9/CYP2C19 genes, and found significant effect of genetic polymorphisms on drug metabolism (Ther Drug Monit. 2004;26:534-540). As been published, the director of population genetics of Duke University, David B Goldstein, paid highly attention on our work, and actively asked for cooperation. We had conducted a very good cooperation on SCN1A gene (Pharmacogenet Genomics. 2006;16:721-726). In the study of intractable epilepsy, we have identified several haplotypes in ABCB1 gene which were associated with epilepsy treatment responses and investigated the role of NR1I2 gene in intractable epilepsy (Pharmacogenomics 2005;6:411-417; Pharmacogenomics 2007;8:1151-1158). The basic studies of mechanisms of antiepileptic drugs interacted with Pgp are undergoing. Intractable epilepsy represents a major problem in epilepsy treatment. While the underlying mechanism of intractable epilepsy is not completely understood, a decrease in brain drug concentrations caused by efflux systems located in the blood-brain barrier (BBB) would be plausible. Because of its luminal membrane location, high expression level, potency, and ability to transport therapeutics, P-gp is considered a primary obstacle to drug penetration of the BBB. Thus, altering P-gp activity has the potential to selectively open the barrier to many CNS-active drugs. It has been demonstrated that, in isolated rat brain capillaries, endothelin-1 (ET-1), acting through an ETB receptor, NO synthase, and protein kinase C, rapidly and reversibly reduces P-gp transport function. Thus NO may play a role in the regulation of P-gp transport function. Nitric oxide (NO) is a small signaling molecule involved in different cellular functions, including growth, differentiation and apoptosis. In many cell types a great variety of stimuli, such as bacterial lipopolysaccharide, cytokines, oxidative stress, and statins, stimulate the production of high amounts of NO via the activation of the nuclear factor-kB (NF-kB) transcription factor, which subsequently increases the expression of inducible NOS (iNOS). YC-1, a novel synthetic compound [3-(5-hydroxymethyl-2-furyl)-1-benzyl-indazole], also produced an enormous stimulation of the sensitivity of the purified enzyme to NO up to several hundredfold. Since NO is known to be involved in alteration of P-gp transport function, it is possible that statins and YC-1 may attenuate the efflux function of P-gp. Taken together, the objectives of the study are: (1) To assess the effect of YC-1 on P-gp transport function; (2) To identify the pathway and the mechanism of YC-1 involved P-gp regulation; (3) To assess whether the effect of YC-1 is influenced by SNPs in P-gp and evaluate the possible binding site of YC-1; (4) To assess the effect of statins on P-gp transport function; (5) To identify the pathway and the mechanism of statins involved P-gp regulation; (6) To assess whether the effect of statins is influenced by SNPs in P-gp and evaluate the possible binding site of statins; (7) To investigate the effect of YC-1 and statins on antiepileptic drugs penetration through BBB. After complete this project, we can understand the genetic and functional importance of MDR1 polymorphism in multidrug-resistant epilepsy. These results not only provide useful information for neurologists in clinical management patients with epilepsy but also for basic scientists in development new drug candidate to revert the multidrug resistance. P-glycoprotein Genetic susceptibility loci Multidrug-resistant epilepsyNO modulatorsYC-1 Statins Pathway/Mechanism Binding site BBB model The flow chart of the study |
