摘要:此計畫為我們繼之前生技製藥(NSTPB)與生技醫藥(NRPB)國家型計畫成果的延續性計畫。我們研發出一個對於治療具感覺門控缺陷的神經科或精神疾患有潛力的化合物,KLP-1。感覺門控缺(sensorimotor gating deficit, SGD)SGD 常表現於精神分裂症、妥瑞症、強迫症與注意力不足過動症等神經精神疾患。SGD 可以在人類與動物模式藉由測量前脈衝抑制功能(prepulse inhibition, PPI)缺損來評估。KLP-1 為一種自本地草藥葉萃取出的類黃酮,我們在一個小兒神經科臨床個案觀察到該草藥葉可以有效緩解頑固型性抽動。KLP-1 可以改善動物模式中的過動症(甲基安非他命引起)、PPI 缺損(甲基安非他命與 NMDA 離子通道抑制劑引起)與社交退縮行為(phencyclidine 引起)。改善社交退縮的結果顯現 KLP-1 具有治療精神分裂症負性症狀的潛力,該負性症狀是目前仍無滿意治療方法的醫療需求。在92 個受體/酵素的結合篩選中,KLP-1 對毒性標地(如會引起 QT 延長的 hERK)無明顯親合力,只對6個藥效標的具親合力,尤其對COMT 及benzodiazepine/GABAA受體具高親合力(micromolar)。KLP-1 是多種 GABAA 受體的正向變構調節劑(positive allosteric modulator, PAM),包括只在小腦顆粒細胞表現的 α6GABAA 受體。藉由藥理學與小腦給藥的方法,我們證實 KLP-1 經由正向調節 α6GABAA 受體來抑制過動症,藉由正向調節 α6GABAA受體和 COMT 抑制改善 PPI 缺損,而經由 COMT 抑制改善社交退縮行為。此外,我們也於 GLP-基因毒性測試中確認KLP-1 並無基因毒性,藥動學方面文獻報告也顯示 KLP-1 能被吸收以原形作用,並容易穿越血腦屏障。我們也已建構一個化學合成製程可容大量合成 KLP-1。 在此延伸計畫中,我們將會大量合成 KLP-1 (目標 1),以供應更進一步的臨床前試驗,包括動物安全性藥理、毒理和藥物動力學試驗(目標 2-3)。此外,我們將會使用電腦重建技術,利用 KLP-1 作為一個先導藥物來闡明 α6GABAA 受體和COMT 結構與活性之間的關係 (目標 4)。希望能夠經由上述受體/酵素的離體結合篩選及動物測試,找到強效、具高選擇性且同時作用於 α6GABAA 受體和 COMT的雙重配體 (目標 5)。我們期待透過由化學、結構生物學及藥理學三個專業實驗室集結成的團隊合作,以及 NRPB 資源中心的支持,希望能夠研發出可申請新藥臨床試驗(IND)的候選藥物。
Abstract: This is a continuation proposal of our previous NRPB project where we have identified a potential compound, KLP-1, for the treatment of sensorimotor gating deficit (SGD) associated neuropsychiatric disorders, including, but not limited to, schizophrenia, Tourrette syndrome (TS), compulsive disorder and attention deficit hyper-reactive disorder. SGD can be reflected by a disruption in prepulse inhibition of the startle reflex (PPI) in animal models and in humans. KLP-1 is a flavonoid isolated from the leave extract of a local herb, which effectively remitted intractable motor tics in a patient at our pediatric neurological clinic. KLP-1 was effective in animal models hyperlocomotion (methamphetamine-induced) and PPI disruptions (methamphetamine- and NMDA channel blocker-induced). KLP-1 also improved social withdraw behaviors in chronic phencyclidine-treated mice, which reflects negative symptoms in schizophrenic patients, an unmet medical need. Binding screening assays on 92 receptors/enzymes revealed that KLP-1 at 10 μM displayed binding affinity at only 6 ON targets, especially having micromolar affinity at the catechol-O-methyl-transferase (COMT) and benzodiazepine/GABAARs. KLP-1 is a positive allosteric modulator (PAM) of GABAARs, including the cerebellar-exclusively expressed α6 subunit consisting GABAARs (α6GABAARs). Through pharmacological and anatomical approaches, our results suggest that KLP-1 inhibits MA-induced hyperlocomotion via α6GABAAR PAM effect, rescues PPI disruption via both α6GABAAR PAM and COMT inhibiting effects, and improves social withdrawal via COMT inhibition. Besides, we have also established a feasible chemical synthesis scheme for KLP-1 and confirmed that KLP-1 was non-genotoxic via the GLP-genotoxicity test. KLP-1 has been reported to be absorbed without any structural modification, and is a high BBB penetrating agent. In this continuation proposal, we will scale up the synthesis of KLP-1 (Aim 1) for conducting further preclinical studies of KLP-1, including safety pharmacology, toxicology and pharmacokinetic studies (Aims 2-3). Besides, we will use KLP-1 as a lead ligand to elucidate the structure-activity relationship targeting on both α6GABAARs and COMT using the computer modeling technique (Aim 4) and hopefully to develop potent and selective dual-target ligands acting on α6GABAARs and COMT via the in vitro binding/enzyme assay and in vivo behavioral testes (Aim 5). Through a collaborative team consisting of three laboratories specialized in chemistry, structure biology and pharmacology, as well as the support from NRPB resource centers, ultimately we wish to develop a drug candidate, which can be filed for IND.