小清蛋白中间神经元损伤可能是精神分裂症发生发展的中心环节
Parvalbumin Interneuron Damage Plays a Central Role in the Pathogenesis of Schizophrenia
摘要: 小清蛋白中间神经元(parvalbumin interneuron, PVI)是一种具有长期发育轨迹的神经元群体,容易受到出生后危险因素的影响和伤害。本文系统复习了可能导致PVI损伤的危险因素,包括多巴胺能系统亢进、NMDA受体被阻断和氧化应激。这些因素均在精神分裂症的疾病发生中起重要作用。损伤的PVI对其下游的神经元活动调控障碍,使中脑腹侧被盖区多巴胺能神经元去抑制因而皮层多巴胺释放增加、谷氨酸脱抑制性释放产生兴奋性神经毒性、并影响少突胶质前体细胞(OPC)发育和成熟因而出现髓鞘化障碍。通过这些途径,PVI损伤影响脑高级功能活动,包括认知、情感和社会功能障碍。
Abstract: Parvalbumin interneurons (PVIs) are featured with a long developmental trajectory. They are sen-sitive and susceptible to risk factors in the postnatal life. This article made a systemic review on the risk factors including dopaminergic hyperfunction, blockade of NMDA receptors, and oxidative stress. These risk factors are also involved in the pathogenesis of schizophrenia. Damaged PVIs are unable to effectively regulate their post-synaptic neurons and subsequently result in various out-comes exemplified as elevated dopamine release in cerebral cortex subsequent to the dis-inhibition on dopaminergic neurons in ventral tegmental area of the midbrain, higher levels of glutamate, which is neurotoxicity, resulting from dis-inhibition on glutamatergic neurons, and myelination deficit due to delayed development of oligodendrocyte precursor cells (OPCs) into matured oli-godendrocytes in the brain. Via the above mechanisms, PVI damage may impair the higher brain functions such as cognition, emotion, and sociability in humans thus playing a central role in the pathogenesis of schizophrenia.
文章引用:陈默雷, 赵宏宇, 许海云. 小清蛋白中间神经元损伤可能是精神分裂症发生发展的中心环节[J]. 国际神经精神科学杂志, 2020, 9(1): 1-11. https://doi.org/10.12677/IJPN.2020.91001

1. 引言

小清蛋白中间神经元(Parvalbumin interneurons, PVI)是一种抑制性中间神经元,在维持正常兴奋–抑制平衡和高频神经元同步化活动中起着关键作用,因而对皮层区域间信息整合非常重要 [1]。不同于其他神经元(在胚胎时期发育成熟),PVI在青春期才成熟,因而容易受到生命早期环境因素的影响,比其他神经元更可能发生青春期前损伤 [2]。

1987年Weinberger首次提出精神分裂症的神经发育理论,认为该病是一种神经发育性脑疾病,神经发育异常可以在症状出现之前的发育早期就被检测出来 [3]。后来有人提出,精神分裂症的病因主要是由于大脑皮层微回路中GABA中间神经元的发育异常,影响谷氨酸神经元和GABA神经元之间的相互作用失衡即“兴奋–抑制平衡”失调,使局部脑连接异常,导致认知、情感和社会功能障碍 [4]。

本文通过复习相关文献,总结了导致PVI损伤的上游因素和PVI损伤后的下游进程,提出小清蛋白阳性中间神经元损伤可能是精神分裂症发生发展的中心环节。

2. 小清蛋白中间神经元

在多种多样的GABA中间神经元中,研究最多的是PVI神经元。它是一种表达特异性钙离子绑定蛋白—小清蛋白(PV)的GABA抑制性中间神经元,具有快放电的特性 [5]。通过与锥体神经元形成抑制性突触,PVI能够使大量锥体神经元的兴奋状态同步化 [6]。PVI能产生节律为30~80 HZ的γ震荡 [7]。皮层γ震荡可以调控锥体细胞的电活动,整合皮层信息传递 [8],因此PVI是高频神经元同步化的关键 [9]。研究发现,大脑皮层内几乎所有的GABA神经元都是表达PV的中间神经元,是主要的有髓中间神经元亚型。PVI的髓鞘化可以很好地优化动作电位保真度并保持其代谢稳态 [10]。

PVI上存在许多神经递质的作用位点包括D2R、5HT1AR和NMDAR等。因此这些神经递质可以通过这些受体影响PVI的功能进而影响脑的高级功能活动。例如PVI的D2R被激活可以增强PVI的GABA抑制作用,抑制锥体神经元的功能活动。选择性敲除PVI上的D2R引起小鼠腹侧海马抑制性活动下降和多巴胺系统失调,出现精神分裂症样症状 [6]。PVI的NMDA受体是维持该类神经元正常γ节律和认知行为的关键,因为NMDA受体拮抗剂可以改变γ节律,并且导致认知障碍和精神病样症状 [11]。

GABA中间神经元的前体来源于胚胎期的内侧神经节突起 [12] [13]。在小鼠脑内,PVI从内侧神经节突起到皮质的迁移大约在胚胎第15~17天完成,但是PVI的成熟过程却直到出生后大约第5天才开始。在生后第5天左右,GABA中间神经元开始对GABA和谷氨酸产生反应。到了出生后第7天,它们开始表达PV。在接下来的3周内,它们慢慢地成熟为快放电的抑制性中间神经元。在成熟的PVI中特异性表达的大多数基因早在出生后的第2到4四周之间就已经开始表达,这与其电生理学成熟的时间相一致。PVI是皮层所有抑制性神经元中最后一个成熟的亚型,在人类和非人灵长类中均是如此 [14]。

3. PVI周围网络

神经元周围网络(perineuronal nets, PNNs)主要由透明质酸、硫酸软骨素蛋白多糖、连接蛋白和张力蛋白R组成 [15]。这些分子相互作用在神经元周围形成稳定的复合物。研究发现,脑内大部分的PNN围绕在具有快放电特性的PVI周围并且与学习和记忆功能密切相关 [16]。部分谷氨酸神经元周围也存在PNN [17]。PNNs完全包绕神经元,并作为物理屏障提供神经保护作用。已经证明,PNNs可以帮助维持神经元存活,抵抗β淀粉样蛋白的神经毒性 [18]。

PNNs中的粘多糖成分带有大量负电荷,这些负电荷形成神经元周围的富阴离子环境,能在局部环境中与各种阳离子结合,调控钠、钾、钙等离子的扩散。通过提供一种快速的阳离子交换,PNNs支持这些快放电神经元的高活性 [16] [19]。PNNs也参与信号转导并调控突触形成以及突触可塑性 [20]。

4. PVI介导脑内多巴胺系统功能亢进及情绪和认知功能障碍

4.1. 精神分裂症的多巴胺假说

在精神分裂症研究中有一个重要理论是所谓的多巴胺假说。该假说源于在动物实验中发现有抗精神病作用的药物能够阻断多巴胺受体 [21]。之后发现,抗精神病药物对多巴胺受体的亲和力与临床疗效之间有相关性,因而多巴胺假说开始为越来越多的临床医生和学者接受 [22]。1991年Davis等人修正精神分裂症的多巴胺理论,认为病人的阴性症状和认知障碍可能是由于中脑–皮层多巴胺投射减少导致前额叶D1受体刺激不足,病人的阳性症状是由于中脑-纹状体多巴胺投射过多导致纹状体D2受体过度激活 [23]。尽管多巴胺能假说已经成为关于精神分裂症发病机制的众多假说之中最为经典的一个,但是鲜有直接证据说明多巴胺系统本身功能障碍。近年来有研究提示PVI损伤与多巴胺系统功能障碍密切相关。

4.2. PVI介导动物脑内多巴胺系统功能亢进及情绪和认知功能障碍

动物研究发现,青春期小鼠暴露于多巴胺转运体抑制剂导致PVI丢失、氧化应激标记物升高及成年期行为改变 [24],提示突触间隙多巴胺水平增高可能导致PVI数量减少。在另一项研究中,D2R基因敲除小鼠出生后第14天前扣带回皮质内GAD 67阳性神经元(GAD 67是谷氨酸脱羧酶67,是将谷氨酸转换成GABA的限速酶)和PVI的数量持续上调,而其他标记物标记的GABA中间神经元的数量未受影响 [25]。已经知道,D2R基因缺失会导致发育过程中多巴胺神经元减少;D2R基因敲除小鼠表现出抑郁样行为减少 [26] ;抑郁与人类大脑皮质GABA水平下降有关 [27] [28] ;额叶皮层GABA神经元PV的表达或活性下降与人类的抑郁和啮齿类动物的抑郁样行为有关 [28]。所以上述研究结果可以解释为,D2R基因敲除所导致的发育过程中DA神经元数量下降使大脑皮层的GABA水平升高,因而减少抑郁样行为。

纹状体投射神经元按照基因表达和轴突投射靶点的不同分为两种,其中表达多巴胺D1R的神经元形成促进运动的直接通路,而表达D2R的神经元形成抑制运动的间接通路 [29] [30]。纹状体的PVI与皮层神经元直接接触,接受多个皮层神经元的汇聚投射并与多个中棘神经元形成突触连接,在局部脑区构成PVI微回路,因而协调地抑制数千个投射神经元的活动 [31]。实验发现,用6-OHDA耗竭多巴胺后第3天发现纹状体的单个PVI与间接通路神经元的连接增加了一倍,而与直接通路的连接保持不变 [32],提示多巴胺耗竭可能增强PVI的功能,导致对间接通路的同步性抑制增加,但对直接通路的抑制作用保持不变。这种解释可能帮助理解巴金森病(PD)的神经病理和病人的运动症状。

研究发现,应激使杏仁基底外侧核的DA释放增加,后者(DA)通过cAMP依赖性信号系统抑制PVI轴突末梢释放GABA到主神经元(但不影响GABA释放到中间神经元)进而解除主神经元抑制和增强其感觉输入的突触可塑性,促进恐惧学习 [33]。该实验结果也说明过量的多巴胺影响了PVI的正常功能,抑制了PVI的GABA释放,导致下游主神经元去抑制。

总之,多巴胺系统功能亢进既可以通过减少PVI的数量,也可以通过影响PVI的功能,影响局部脑连接并导致认知和行为障碍。所以,是PVI介导了脑内多巴胺系统功能亢进和某些异常行为,包括情绪和认知障碍。显然,进一步研究多巴胺系统与PVI之间的关系和相互作用对于阐明PVI在精神疾病中所扮演的角色有重要意义。

5. PVI介导脑内NMDA功能低下和精神分裂症样行为

5.1. NMDA受体

N-甲基-D-天冬氨酸受体(NMDAR)是一种谷氨酸离子型受体,谷氨酸作用于NMDAR使之激活进而使细胞膜去极化和神经元兴奋。NMDAR广泛分布于全脑,介导整个大脑的兴奋性突触后电位。NMDAR 的组成包括两个必须的GluN1亚基和两个与之相连的GluN2亚基 [34]。NMDAR上存在多种调节位点,多种内源性或外源性物质可以对其进行调节。例如甘氨酸和D-丝氨酸是GluN1亚基上甘氨酸调节位点的内源性协同激动剂,D-环丝氨酸是甘氨酸调节位点的部分激动剂,而犬尿喹啉酸是甘氨酸调节位点的内源性拮抗剂;谷氨酸和NMDA是GluN2亚基上谷氨酸调节位点的激动剂 [35]。

5.2. 精神分裂症的谷氨酸假说

谷氨酸假说的提出基于发现使用NMDAR拮抗剂苯环己哌啶(PCP)或氯胺酮可以导致受试动物表现类似精神分裂症的阳性症状、阴性症状和认知功能障碍 [36]。现在普遍认为NMDAR功能低下是人类认知功能障碍的重要原因之一,并与精神分裂症的发病密切相关。

5.3. NMDAR功能低下导致PVI损伤和精神分裂症样行为

使用非选择性的NMDAR 拮抗剂(PCP或氯胺酮)可以干预记忆的形成,并产生类似精神分裂症的某些症状 [37]。铅是NMDAR的一种强有力的拮抗剂。早期铅暴露可导致青春期大鼠相关脑区的PVI减少,PV和GAD 67蛋白表达明显降低并且出现精神分裂症样行为。但是,GABA中间神经元表达的钙视网膜蛋白calretinin或钙结合蛋白calbindin水平无明显变化,提示NMDAR抑制选择性地影响GABA中间神经元的PVI亚型 [38]。在另一项研究中,NMDAR NR1亚基的基因被选择性敲除的小鼠,NMDAR功能低下并表现兴奋–抑制平衡失调、PVI损伤、和锥体神经元兴奋性增加,以及空间工作记忆和社会交往缺陷 [39]。在出生后的发育期选择性清除40%~50%的皮层和海马中间神经元的NMDAR的NR1亚基造成NMDAR功能低下,GAD 67和PV表达减少、皮层兴奋性神经元的兴奋性增加,但同步性降低。但是,青春期后NR1的缺失并没有导致这些异常 [40],提示发育期的PVI对NMDAR功能低下更加敏感且易受损害。大量研究显示NMDAR 拮抗剂主要降低GABA中间神经元的兴奋性,但增加大部分皮层神经元的兴奋性,并导致精神分裂症样表现。所以,可能是NMDAR功能低下选择性地抑制了PVI的兴奋性进而使与之连接的锥体神经元去抑制而导致皮层兴奋 [41]。但是,直接激活NMDAR的谷氨酸结合位点则会引发兴奋毒性,导致神经元死亡 [42]。

6. 氧化应激损害PVI

6.1. 氧化还原平衡

生活状态下,细胞的线粒在氧化磷酸化过程中生成ATP,同时产生活性氧簇(ROS)。ROS主要包括超氧阴离子(O2−)和过氧化氢(H2O2)。正常情况下机体的抗氧化系统会清除ROS,其中超氧化物歧化酶(SOD)将超氧阴离子转变为过氧化氢,后者经过氧化氢酶(CAT)、谷胱甘肽(GSH)以及谷胱甘肽过氧化物酶(GSH-Px)作用后,最终被还原成水 [43]。机体通过此机制保持氧化还原平衡。如果ROS产生过多或细胞抗氧化能力下降,超出了机体正常氧化还原调节的范围,过量的ROS会造成蛋白质、脂质、糖类和核酸的结构改变或破坏,进而导致细胞凋亡、坏死,和其他细胞结构的损伤,此即氧化应激 [44]。在许多精神疾病和神经退行性疾病中,如精神分裂症、老年痴呆症、PD和亨廷顿病都存在氧化应激 [45]。

6.2. 氧化应激损害PVI

有研究提出,氧化应激是导致精神分裂症患者PVI损伤的一个病理机制。一系列具有遗传或环境危险因素的PVI损伤动物模型显示,PVI缺陷都伴随着氧化应激的存在 [1]。具体来说,氧化应激会延缓PVIs的成熟或者减少PVIs的数量并且使包绕这些中间神经元的细胞外基质所构成的PNN也受到损伤从而影响PVI突触传递的稳定性,而且导致受PVI调节的γ振荡活动也发生异常 [14]。目前在多种动物模型中已经成功地应用抗氧化剂或者氧化还原调节剂来保护PVI免遭氧化应激的损害 [1]。

实验研究发现,谷胱甘肽合成受损的谷胺酸半胱胺酸连接酶修饰亚单位基因[GcIm(-/-)]敲除小鼠PVI易受氧化应激的伤害。谷胱甘肽缺乏延迟PVI及其PNN的成熟。此外,在GcIm(-/-)小鼠断奶前或青春期的一个额外氧化应激可导致PVI的数量减少。这种影响持续至成年,并可被抗氧化剂N-乙酰半胱氨酸预防 [46]。另有研究显示,铁缺乏和铁过量都可以导致大鼠线粒体损伤进而导致氧化应激 [47] ;生命早期发生的缺铁性贫血可以导致大鼠海马的PV表达减少和PNN损伤 [48]。这些研究结果表明,缺铁性贫血所致的氧化应激影响PVI发育成熟,并破坏这类神经元的PNN。

特别值得注意的是,氧化应激参与了多巴胺系统功能亢进和阻断NMDAR导致的PVI损伤。例如,给青春期小鼠腹腔注射多巴胺转运体抑制剂GBR12909后检测到小鼠前额叶的8-oxo-dG表达水平升高,同时发现该脑区的PVI数量减少 [24]。此结果提示,突触间隙多巴胺升高导致了神经组织的氧化应激并造成PVI损害,因为8-oxo-dG是DNA被ROS损伤后的产物,常用来检测氧化损伤。在另一项研究中,给大鼠腹腔注射NMDAR拮抗剂苯环已哌啶(PCP)后检测到大鼠额叶背外侧部、海马、和尾状核的GSH含量减少,额叶背外侧部的SOD含量减少,海马和丘脑脂质过氧化物(MDA)含量升高,提示阻断NMDAR导致氧化应激 [49],后者可以损害PVI。支持此种解释的实验结果还包括:NMDAR 拮抗剂氯胺酮在小鼠诱发氧化应激,脑内PVI和GAD67阳性神经元减少 [50]。

7. PVI损伤可能是精神分裂症发生发展的中心环节

上文复习了能导致脑内PVI损伤或功能低下的几种危险因素,包括多巴胺系统功能亢进、NMDAR被阻断或功能低下、以及氧化应激。这些因素都参与了精神分裂症的疾病发生和发展过程。在下文我们将扼要介绍PVI损伤或功能障碍之后的下游事件或结局,并讨论这些下游事件在精神分裂症发生发展中的病理生理学意义。

7.1. PVI损伤导致中脑腹侧被盖区多巴胺神经元去抑制及多巴胺释放增加

已经知道,腹侧海马的谷氨酸神经元投射到伏隔核兴奋该处的GABA神经元;伏隔核的GABA神经元投射到苍白球抑制该处的GABA神经元;苍白球的GABA神经元投射到中脑腹侧被盖区抑制该区的多巴胺神经元,使之变成静息状态 [51] [52]。在腹侧被盖区,只有兴奋状态的多巴胺神经元可以接受脑桥被盖区谷氨酸神经元的输入,因而被激活并释放大量多巴胺。正常情况下GABA神经元的抑制性输入使得多巴胺神经元的静息状态和活化状态保持平衡 [53]。研究发现,在小鼠甲氮氧甲醇乙酸甲酯精神分裂症模型中,出现海马过度活跃和节律失调、海马PVI数量减少和多巴胺系统亢进 [54] [55]。选择性地减少PV的mRNA表达导致腹侧海马神经元高度活跃、下游多巴胺神经元活动增加,因而增强对苯丙胺的运动反应 [56]。

大脑皮层和海马的GABA中间神经元的前体大多数来源于胚胎内侧神经节突起 [12] [13]。细胞周期蛋白D2 (Ccnd 2)是一种G1期活性细胞周期蛋白,表达于内侧神经节突起的脑室下区。研究发现,Ccnd 2基因缺失突变会导致内侧神经节突起的增殖降低,使大脑皮层和海马的PVI密度降低但不影响谷氨酸投射神经元或其他中间神经元亚型的密度 [57] [58]。Ccnd 2基因敲除[Ccnd 2(-/-)]小鼠的大脑皮层PVI减少,尤其是在海马区明显减少,海马投射神经元尖峰放电活动增加,海马在静息状态下的活动水平升高。Ccnd 2(-/-)小鼠还表现出多种神经生理学和行为学表型包括腹侧被盖区多巴胺神经元群活动增多,对苯丙胺更加敏感,以及海马依赖性的认知损害。如果将胚胎内侧神经节突起(大脑皮层中间神经元的主要来源)的细胞移植到成年Ccnd 2(-/-)腹侧海马,可逆转这些精神病相关表型。这些移植后存活的神经元的97%是GABA神经元并且广泛分布在海马内 [59]。这些结果提示,腹侧海马PVI损伤通过腹侧海马-伏隔核-苍白球通路导致多巴胺系统功能增强和增加对苯丙胺的敏感性。所以,可以声称,PVI损伤是精神分裂症病理生理学的重要环节。理论上纹状体部位的PVI损伤后也可以直接导致腹侧被盖区的多巴胺神经元去抑制,转变为活化状态,使大量的多巴胺神经元被激活,增加皮层下多巴胺释放,导致精神分裂样行为。未来的研究应该去检验以上假设。

7.2. PVI受损导致锥体神经元去抑制,Glu释放过度产生兴奋性神经毒性

PVI受损使其对突触后神经元的抑制作用减弱,导致锥体神经元去抑制,后者可能导致谷氨酸神经元过度兴奋,进而通过兴奋性神经毒性导致神经元损伤或死亡。研究表明,PVI的GAD 67缺乏导致GABA合成障碍,同时发现锥体神经元兴奋性增加,前额叶皮层从PVI到锥体神经元的传输出现明显缺陷。这可能是疾病状态下的皮质功能障碍的原因 [60]。急性PCP给药(2 mg/kg)增加PFC处的谷氨酸水平(p < 0.05),并显著降低该脑区的PV和GAD-67 (p < 0.001)水平。这种效果维持至用药后第10天,并通过重复注射PCP而保持不变 [61]。这些发现提示,皮质谷氨酸传递异常可能是因为GABA神经元中的PVI减少或其功能抑制,导致谷氨酸脱抑制性释放,这或许是部分精神分裂症患者的认知缺损的原因。此外,多次亚麻醉剂量的氯胺酮导致PVI功能障碍,产生精神病样效应。30 mg/kg氯胺酮重复给药可诱发刻板行为和多动,PV和GAD 67阳性神经元减少,脑组织的谷氨酸水平升高,但GABA水平降低 [62]。提示PVI减少或功能障碍后,谷氨酸神经元脱抑制,释放谷胺酸增加,产生兴奋性神经毒性。

7.3. PVI通过OPC-PVI连接影响少突胶质细胞系的发育和成熟

成熟少突胶质细胞(OL)是中枢神经系统内的髓鞘形成细胞,其前体细胞(少突胶质前体细胞,OPC)主要来源于前脑的脑室下区。从OPC到成熟的OL,需经历早期OPC、晚期OPC、未成熟OL、和成熟OL四个发育阶段 [63]。部分OPCs在出生后的早期发育成熟,成为成熟OL,后者的细胞突起缠绕神经元的轴突形成髓鞘。另有部分OPCs保持在休眠状态,它们均匀地分布在中枢神经系统的灰质和白质。特别值得注意的是,皮层的一些OPCs的胞体与神经元的胞体非常接近,它们相连或交织在一起形成了极为密切的解剖学联系,即所谓的OPC-神经元对。对于OPC-神经元对的组织学分析表明,在大脑皮层GABA中间神经元是OPC-神经元对中最常见的神经元成分 [64]。最近的研究表明,大脑皮层V层的OPC与PVI建立了直接的功能性胞体接触。OPC上存在GABA受体,所以它们能从PVI获得较强的GABA突触输入 [9]。GABA受体被激活引起OPC去极化 [64],局部GABA中间神经元的突触输入可动态调节OPC向成熟OLs的发育进程 [65]。

OPC-PVI连接的神经发育高峰出现在生后第10~14天 [66]。这与人类额叶皮质少突胶质细胞的发育时间吻合,因此推测此时期PVI可能调节OPCs发育和成熟为OLs。研究发现,发育中的体感皮层的NG2阳性细胞(NG2是OPCs的特异性标志物)与GABA快放电中间神经元之间形成一个短暂的、结构化的突触网络并遵循自己的连接规则。这种微电路结构在出生后第10天完全成熟,此时大量OPCs发育成熟,形成成熟的OLs,提示NG2阳性细胞受GABA神经支配,完成其发育过程并加入神经网络 [9]。

在弥漫性白质损伤小鼠模型中,缺氧导致OPC-PVI神经连接中GABA A受体介导的突触输入减少,NG2阳性细胞大量增殖,但是它们向OL的发育过程延迟,导致髓鞘化障碍。用GABA A受体拮抗剂处理小鼠也可模拟缺氧的作用出现相同的表现。相反,阻断GABA分解代谢或GABA再摄取可减少NG2阳性细胞的数量,但增加对照组小鼠和缺氧小鼠成熟OLs的数量,表明GABA神经信号调控NG2阳性细胞的发育过程 [65]。

在OPC-PVI神经连接体中PVI影响OPC发育和OL成熟让我们联想到精神分裂症的另一个理论,即所谓的少突胶质理论。按照该理论,少突胶质细胞发育障碍或功能损害,甚至死亡可能是精神分裂症发生发展过程的一个重要因素 [66]。该理论的主要依据包括神经影像学显示的部分首发分裂症病人脑白质异常,如白质的完整性降低(FA值较正常对照低)、脑室体积增大、和脑白质体积减小 [66] [67] ;分子遗传学报道的分裂症病人及高风险近亲的OL相关基因的表达水平降低 [68] ;动物和细胞培养实验发现的抗精神病药对少突胶质细胞系发育和成熟的影响 [69] [70] [71] [72],等等。未来的研究应该检查通过改变OPC-PVI神经连接体中PVI的功能状态影响少突胶质细胞系的发育是否能改变动物的行为学表型,导至精神分裂样行为异常。

8. 结束语

精神分裂症是一种严重且极其复杂的精神疾病。虽历经100多年的研究,人们对该病的认识还不全面和深入。现有的神经发育学说、多巴胺理论、谷胺酸理论,和少突胶质细胞理论等,均只触及该病发生发展过程的某一方面。通过系统地复习文献,我们提出PVI损伤可能是精神分裂症发生发展过程的中心环节。终结本文所述,多巴胺神经系统功能亢进、谷氨酸系统失调、和氧化应激都会导致PV阳性GABA中间神经元损伤,继而导致中脑腹侧被盖区多巴胺神经元去抑制及多巴胺释放增加,锥体神经元去抑制因而Glu释放过度产生兴奋性神经毒性,延缓少突胶质细胞系的发育和脑白质髓鞘化过程,最终出现精神分裂症的临床表型,包括认知、情感和社会功能障碍。

NOTES

*通讯作者。

参考文献

[1] Steullet, P., Cabunqcal, J.H., Coyle, J., et al. (2017) Oxidative Stress-Driven Parvalbumin Interneuron Impairment as a Common Mechanism in Models of Schizophrenia. Molecular Psychiatry, 22, 936-943.
https://doi.org/10.1038/mp.2017.47
[2] Tseng, K. and O’Donnell, P. (2007) Dopamine Modulation of Prefrontal Cortical Interneurons Changes during Adolescence. Cerebral Cortex, 17, 1235-1240.
https://doi.org/10.1093/cercor/bhl034
[3] Weinberger, D.R. (1987) Implications of Normal Brain Development for the Pathogenesis of Schizophrenia. Archives of General Psychiatry, 44, 660-669.
https://doi.org/10.1001/archpsyc.1987.01800190080012
[4] Schmidt, M.J. and Mimics, K. (2015) Neurodevelopment, GABA System Dysfunction, and Schizophrenia. Neuropsychopharmacology, 40, 190-206.
https://doi.org/10.1038/npp.2014.95
[5] Hu, H., Gan, J. and Jonas, P. (2014) Interneurons. Fast-Spiking, Par-valbumin GABAergic Interneurons: From Cellular Design to Microcircuit Function. Science, 345, Article ID: 1255263.
https://doi.org/10.1126/science.1255263
[6] Tomasella, E., Bechelli, L., Ogando, M.B., et al. (2018) Deletion of Dopamine D Receptors from Parvalbumin Interneurons in Mouse Causes Schizophrenia-Like Phenotypes. Proceedings of the National Academy of Sciences of the United States of America, 115, 3476-3481.
https://doi.org/10.1073/pnas.1719897115
[7] Cardin, J.A., Carlen, M., Meletis, K., et al. (2009) Driving Fast-Spiking Cells Induces Gamma Rhythm and Controls Sensory Responses. Nature, 459, 663-667.
https://doi.org/10.1038/nature08002
[8] Salinas, E. and Sejnowski, T. (2001) Correlated Neuronal Activity and the Flow of Neural Information. Nature Reviews Neuroscience, 2, 539-550.
https://doi.org/10.1038/35086012
[9] Orduz, D., Maldonado, P.P., Balia, M., et al. (2015) Interneurons and Oligoden-drocyte Progenitors form a Structured Synaptic Network in the Developing Neocortex. Elife, 22, 4.
https://doi.org/10.7554/eLife.06953
[10] Stedehouder, J. and Kushner, S. (2017) Myelination of Parvalbumin In-terneurons: A Parsimonious Locus of Pathophysiological Convergence in Schizophrenia. Molecular Psychiatry, 22, 4-12.
https://doi.org/10.1038/mp.2016.147
[11] Carlen, M., Meletis, K., Sieqle, J.H., et al. (2012) A Critical Role for NMDA Receptors in Parvalbumin Interneurons for Gamma Rhythm Induction and Behavior. Molecular Psychiatry, 17, 537-548.
https://doi.org/10.1038/mp.2011.31
[12] Tyson, J.A. and Anderson, S.A. (2014) GABAergic Interneu-ron Transplants to Study Development and Treat Disease. Trendsin Neurosciences, 37, 169-177.
https://doi.org/10.1016/j.tins.2014.01.003
[13] Tricoire, L., Pelkey, K.A., Erkkila, B.E., et al. (2011) A Blueprint for the Spatiotemporal Origins of Mouse Hippocampal Interneuron Diversity. Journal of Neuroscience, 31, 10948-10970.
https://doi.org/10.1523/JNEUROSCI.0323-11.2011
[14] Powell, S.B., Sejnowski, T.J. and Behrens, M.M. (2012) Behavioral and Neurochemical Consequences of Cortical Oxidative Stress on Parvalbumin-Interneuron Maturation in Rodent Models of Schizophrenia. Neuropharmacology, 62, 1322-1331.
https://doi.org/10.1016/j.neuropharm.2011.01.049
[15] Köppe, G., Bruckner, G., Hartiq, W., Delpech, B. and Bigl, V. (1997) Characterization of Proteoglycan-Containing Perineuronal Nets by Enzymatic Treatments of Rat Brain Sections. The Histochemical Journal volume, 29, 11-20.
https://doi.org/10.1023/A:1026408716522
[16] Härtiq, W., Sinqer, A., Grosche, J., et al. (2001) Perineuronal Nets in the Rat Medial Nucleus of the Trapezoid Body Surround Neurons Immunoreactive for Various Amino Acids, Calcium-Binding Proteins and the Potassium Channel Subunit Kv3.1b. Brain Research, 899, 123-133.
https://doi.org/10.1016/S0006-8993(01)02211-9
[17] Wegner, F., Hartiq, W., Brinqmann, A., et al. (2003) Diffuse Perineuronal Nets and Modified Pyramidal Cells Immunoreactive for Glutamate and the GABA(A) Receptor Alpha1 Subunit form a Unique Entity in Rat Cerebral Cortex. Experimental Neurology, 184, 705-714.
https://doi.org/10.1016/S0014-4886(03)00313-3
[18] Miyata, S., Nishmura, Y. and Nakashima, T. (2007) Perineuronal Nets Protect against Amyloid Beta-Protein Neurotoxicity in Cultured Cortical Neurons. Brain Re-search, 1150, 200-206.
https://doi.org/10.1016/j.brainres.2007.02.066
[19] Härtig, W., Derouiche, A., Welt, K., et al. (1999) Cortical Neurons Immunoreactive for the Potassium Channel Kv3.1b Subunit Are Predominantly Surrounded by Perineuronal Nets Presumed as a Buffering System for Cations. Brain Research, 842, 15-29.
https://doi.org/10.1016/S0006-8993(99)01784-9
[20] Carulli, D., Kwok, J.C. and Pizzorusso, T. (2016) Perineu-ronal Nets and CNS Plasticity and Repair. Neural Plasticity, 2016, Article ID: 4327082.
https://doi.org/10.1155/2016/4327082
[21] Carlsson, A. and Lindqvist, M. (1963) Effect of Chlorpromazine or Haloperidol on Formation of 3 Methoxytyramine and Normetanephrine in Mouse Brain. Acta Pharmacologica et Toxi-cologica, 20, 140-144.
https://doi.org/10.1111/j.1600-0773.1963.tb01730.x
[22] Seeman, P. and Lee, T. (1975) Antipsychotic Drugs: Direct Correlation between Clinical Potency and Presynaptic Action on Dopamine Neurons. Sci-ence, 188, 1217-1219.
https://doi.org/10.1126/science.1145194
[23] Davis, K., Kahn, R.S., Ko, G., et al. (1991) Dopamine in Schizophrenia: A Review and Reconceptualization. American Journal of Psychiatry, 148, 1474-1486.
https://doi.org/10.1176/ajp.148.11.1474
[24] Khan, A., de Jong, L.A., Kameski, M.E., et al. (2017) Adolescent GBR12909 Exposure Induces Oxidative Stress, Disrupts Parvalbumin-Positive Interneurons, and Leads to Hyperactivity and Impulsivity in Adult Mice. Neuroscience, 345, 166-175.
https://doi.org/10.1016/j.neuroscience.2016.11.022
[25] Graham, D.L., Durai, H.H., Garden, J.D., et al. (2015) Loss of Dopamine D2 Receptors Increases Parvalbumin-Posi- tive Interneurons in the Anterior Cingulate Cortex. ACS Chemical Neuroscience, 6, 297-305.
https://doi.org/10.1021/cn500235m
[26] Kim, S.Y., Choi, K.C., Chanq, M.S., et al. (2006) The Dopamine D2 Receptor Regulates the Development of Dopaminergic Neurons via Extracellular Sig-nal-Regulated Kinase and Nurr1 Activation. Journal of Neuroscience, 26, 4567- 4576.
https://doi.org/10.1523/JNEUROSCI.5236-05.2006
[27] Sanacora, G., Mason, G.F., Rothman, D.L., et al. (1999) Reduced Cortical Gamma-Aminobutyric Acid Levels in Depressed Patients Determined by Proton Magnetic Resonance Spectroscopy. Archives of General Psychiatry, 56, 1043- 1047.
https://doi.org/10.1001/archpsyc.56.11.1043
[28] Khundakar, A., Morris, C. and Thomas, A.J. (2011) The Immuno-histochemical Examination of GABAergic Interneuron Markers in the Dorsolateral Prefrontal Cortex of Patients with Late-Life Depression. International Psychogeriatrics, 23, 644-653.
https://doi.org/10.1017/S1041610210001444
[29] Bolam, J.P., Hanley, J.J., Booth, P.A. and Bevan, M.D. (2000) Synaptic Organisation of the Basal Ganglia. Journal of Anatomy, 196, 527-542.
https://doi.org/10.1046/j.1469-7580.2000.19640527.x
[30] Kravitz, A.V., Freeze, B.S., Parker, P.R., et al. (2010) Reg-ulation of Parkinsonian Motor Behaviours by Optogenetic Control of Basal Ganglia Circuitry. Nature, 466, 622-626.
https://doi.org/10.1038/nature09159
[31] Trevitt, J.T., Morrow, J. and Marshall, J.F. (2005) Dopamine Manipula-tion Alters Immediate-Early Gene Response of Striatal Parvalbumin Interneurons to Cortical Stimulation. Brain Research, 1035, 41-50.
https://doi.org/10.1016/j.brainres.2004.11.039
[32] Gittis, A.H., Hanq, G.B., LaDow, E.S., et al. (2011) Rapid Target-Specific Remodeling of Fast-Spiking Inhibitory Circuits after Loss of Dopamine. Neuron, 71, 858-868.
https://doi.org/10.1016/j.neuron.2011.06.035
[33] Chu, H.Y., Ito, W., Li, J. and Morozov, A. (2012) Target-Specific Suppression of GABA Release from Parvalbumin Interneurons in the Basolateral Amygdala by Dopa-mine. Journal of Neuroscience, 32, 14815-14820.
https://doi.org/10.1523/JNEUROSCI.2997-12.2012
[34] Traylenis, S.F., Wolluth, L.P., McBain, C.J., et al. (2010) Glutamate Receptor Ion Channels: Structure, Regulation, and Function. Pharmacological Reviews, 62, 405-496.
https://doi.org/10.1124/pr.109.002451
[35] Hashimoto, K. (2014) Targeting of NMDA Receptors in New Treatments for Schizophrenia. Expert Opinion on Therapeutic Targets, 18, 1049-1063.
https://doi.org/10.1517/14728222.2014.934225
[36] Javitt, D.C. (1987) Negative Schizophrenic Symptomatology and the PCP (Phencyclidine) Model of Schizophrenia. The Hillside Journal of Clinical Psychiatry, 9, 12-35.
[37] Olney, J.W., Newcomer, J.W. and Farber, N.B. (1999) NMDA Receptor Hypofunction Model of Schizophrenia. Journal of Psychiatric Research, 33, 523-533.
https://doi.org/10.1016/S0022-3956(99)00029-1
[38] Stansfield, K.H., Ruby, K.N., Soares, B.D., et al. (2015) Early-Life Lead Exposure Recapitulates the Selective Loss of Parvalbumin-Positive GABAergic Interneurons and Subcortical Dopamine System Hyperactivity Present in Schizophrenia. Translational Psy-chiatry, 5, e522.
https://doi.org/10.1038/tp.2014.147
[39] Gandal, M.J., Sisti, J., Klook, K., et al. (2012) GABAB-Mediated Rescue of Altered Excitatory-Inhibitory Balance, Gamma Synchrony and Behavioral Deficits Fol-lowing Constitutive NMDAR-Hypofunction. Translational Psychiatry, 2, e142.
https://doi.org/10.1038/tp.2012.69
[40] Belforte, J.E., Zsiros, V., Sklar, E.R., et al. (2010) Postnatal NMDA Re-ceptor Ablation in Corticolimbic Interneurons Confers Schizophrenia-Like Phenotypes. Nature Neuroscience, 13, 76-83.
https://doi.org/10.1038/nn.2447
[41] Homayoun, H. and Moghaddam, B. (2007) NMDA Receptor Hypofunction Produces Opposite Effects on Prefrontal Cortex Interneurons and Pyramidal Neurons. Journal of Neuroscience, 27, 11496-11500.
https://doi.org/10.1523/JNEUROSCI.2213-07.2007
[42] Collins, S.A., Gudelsky, G.A. and Yamamoto, B.K. (2015) MDMA-Induced Loss of Parvalbumin Interneurons within the Dentate Gyrus Is Mediated by 5HT2A and NMDA Receptors. European Journal of Pharmacology, 761, 95-100.
https://doi.org/10.1016/j.ejphar.2015.04.035
[43] Emiliani, F.E., Sedlak, T.W. and Sawa, A. (2014) Oxida-tive Stress and Schizophrenia: Recent Breakthroughs from an Old Story. Current Opinion in Psychiatry, 27, 185-190.
https://doi.org/10.1097/YCO.0000000000000054
[44] Radi, R. (2018) Oxygen Radicals, Nitric Oxide, and Per-oxynitrite: Redox Pathways in Molecular Medicine. Proceedings of the National Academy of Sciences of the United States of America, 115, 5839-5848.
https://doi.org/10.1073/pnas.1804932115
[45] Ng, F., Berk, M., Dean, O. and Bush, A.I. (2008) Oxidative Stress in Psychiatric Disorders: Evidence Base and Therapeutic Implications. International Journal of Neuropsychopharmacology, 11, 851-876.
https://doi.org/10.1017/S1461145707008401
[46] Cabungcal, J.H., Steullet, P., Kraftsik, R., Cuenod, M. and Do, K.Q. (2013) Early-Life Insults Impair Parvalbumin Interneurons via Oxi-dative Stress: Reversal by N-Acetylcysteine. Biological Psychiatry, 73, 574-482.
https://doi.org/10.1016/j.biopsych.2012.09.020
[47] Walter, P.B., Knutson, M.D., Paler-Martines, A., et al. (2002) Iron Deficiency and Iron Excess Damage Mitochondria and Mitochondrial DNA in Rats. Proceedings of the National Academy of Sciences of the United States of America, 99, 2264-2269.
https://doi.org/10.1073/pnas.261708798
[48] Callahan, L.S., Thibert, K.A., Wobken, J.D. and Georgieff, M.K. (2013) Early-Life Iron Deficiency Anemia Alters the Development and Long-Term Expression of Parvalbumin and Perineuronal Nets in the Rat Hippocampus. Developmental Neuroscience, 35, 427-436.
https://doi.org/10.1159/000354178
[49] Radonjic, N.V., Knezevic, I.D., Vilimanovich, U., et al. (2010) Decreased Glutathione Levels and Altered Antioxidant Defense in an Animal Model of Schizophrenia: Long-Term Effects of Peri-natal Phencyclidine Administration. Neuropharmacology, 58, 739-745.
https://doi.org/10.1016/j.neuropharm.2009.12.009
[50] Behrens, M.M., Ali, S.S., Dao, D.N., et al. (2007) Keta-mine-Induced Loss of Phenotype of Fast-Spiking Interneurons Is Mediated by NADPH-Oxidase. Science, 318, 1645-1647.
https://doi.org/10.1126/science.1148045
[51] Lodge, D.J. and Grace, A.A. (2007) Aberrant Hippo-campal Activity Underlies the Dopamine Dysregulation in an Animal Model of Schizophrenia. Journal of Neuroscience, 27, 11424-11430.
https://doi.org/10.1523/JNEUROSCI.2847-07.2007
[52] Lodge, D.J. and Grace, A.A. (2011) Hippocampal Dysregulation of Dopamine System Function and the Pathophysiology of Schizophrenia. Trends in Phar-macological Sciences, 32, 507-513.
https://doi.org/10.1016/j.tips.2011.05.001
[53] Grace, A.A. and Gomes, F.V. (2019) The Circuitry of Dopamine System Regulation and Its Disruption in Schizophrenia: Insights into Treatment and Prevention. Schizophrenia Bulletin, 45, 148-157.
https://doi.org/10.1093/schbul/sbx199
[54] Lodge, D.J., Behrens, M.M. and Grace, A.A. (2009) A Loss of Parvalbumin-Containing Interneurons Is Associated with Diminished Oscilla-tory Activity in an Animal Model of Schizophrenia. Journal of Neuroscience, 29, 2344-2354.
https://doi.org/10.1523/JNEUROSCI.5419-08.2009
[55] Moore, H., Jentsch, J.D., Ghajarnia, M., Geyer, M.A. and Grace, A.A. (2006) A Neurobehavioral Systems Analysis of Adult Rats Exposed to Methyla-zoxymethanol Acetate on E17: Implications for the Neuropathology of Schizophrenia. Biological Psychiatry, 60, 253-264.
https://doi.org/10.1016/j.biopsych.2006.01.003
[56] Boley, A.M., Perez, S.M. and Lodqe, D.J. (2014) A Funda-mental Role for Hippocampal Parvalbumin in the Dopamine Hyperfunction Associated with Schizophrenia. Schizophre-nia Research, 157, 238-243.
https://doi.org/10.1016/j.schres.2014.05.005
[57] Glickstein, S.B., Moore, H., Slowinska, B., et al. (2007) Selective Cortical Interneuron and GABA Deficits in Cyclin D2-Null Mice. Development, 134, 4083-4093.
https://doi.org/10.1242/dev.008524
[58] Glickstein, S.B., Monaqhan, J.A., Koeller, H.B., Jones, T.K. and Ross, M.E. (2009) Cyclin D2 Is Critical for Intermediate Progenitor Cell Proliferation in the Embryonic Cortex. Journal of Neuroscience, 29, 9614-9624.
https://doi.org/10.1523/JNEUROSCI.2284-09.2009
[59] Gilani, A.I., Chohan, M.O., Inan, M., et al. (2014) Interneuron Precursor Transplants in Adult Hippocampus Reverse Psycho-sis-Relevant Features in a Mouse Model of Hippocampal Disinhibition. Proceedings of the National Academy of Sciences of the United States of America, 111, 7450-7455.
https://doi.org/10.1073/pnas.1316488111
[60] Lazarus, M.S., Krishnan, K. and Huang, Z.J. (2015) GAD67 Deficiency in Parvalbumin Interneurons Produces Deficits in Inhibitory Transmission and Network Disinhibition in Mouse Prefrontal Cortex. Cerebral Cortex, 25, 1290-1296.
https://doi.org/10.1093/cercor/bht322
[61] Amitai, N., Kuczenski, R., Behrens, M.M., et al. (2012) Repeated Phencyclidine Administration Alters Glutamate Release and Decreases GABA Markers in the Prefrontal Cortex of Rats. Neuropharmacology, 62, 1422-1431.
https://doi.org/10.1016/j.neuropharm.2011.01.008
[62] Zhou, Z., Zhang, G., Li, X., et al. (2015) Loss of Phenotype of Parvalbumin Interneurons in Rat Prefrontal Cortex Is Involved in Antidepres-sant- and Propsychotic-Like Behaviors Following Acute and Repeated Ketamine Administration. Molecular Neurobiolo-gy, 51, 808-819.
https://doi.org/10.1007/s12035-014-8798-2
[63] Emery, B. (2010) Regulation of Oligodendro-cyte Differentiation and Myelination. Science, 330, 779-782.
https://doi.org/10.1126/science.1190927
[64] Boulanger, J. and Messier, C. (2017) Oligodendrocyte Progenitor Cells Are Paired with GABA Neurons in the Mouse Dorsal Cortex: Unbiased Stereological Analysis. Neu-roscience, 362, 127-140.
https://doi.org/10.1016/j.neuroscience.2017.08.018
[65] Zonouzi, M., Scafidi, J., Li, P., et al. (2015) GABAergic Regulation of Cerebellar NG2 Cell Development Is Altered in Perinatal White Matter Injury. Na-ture Neuroscience, 18, 674-682.
https://doi.org/10.1038/nn.3990
[66] Davis, K.L., Stewart, D.G., Friedman, J.I., et al. (2003) White Matter Changes in Schizophrenia: Evidence for Myelin-Related Dysfunction. Archives of General Psychiatry, 60, 443-456.
https://doi.org/10.1001/archpsyc.60.5.443
[67] Xu, H. and Li, X.M. (2011) White Mat-ter Abnormalities and Animal Models Examining a Putative Role of Altered White Matter in Schizophrenia. Schizophre-nia Research and Treatment, 2011, Article ID: 826976.
https://doi.org/10.1155/2011/826976
[68] Hakak, Y., Walker, J.R., Li, C., et al. (2001) Genome-Wide Expression Analysis Reveals Dysregulation of Myelination-Related Genes in Chronic Schizophrenia. Proceedings of the National Academy of Sciences of the United States of America, 98, 4746-4751.
https://doi.org/10.1073/pnas.081071198
[69] Tishler, T.A., Bartzokis, G., Lu, P.H., et al. (2018) Ab-normal Trajectory of Intracortical Myelination in Schizophrenia Implicates Whitematter in Disease Pathophysiology and the Therapeutic Mechanism of Action of Antipsychotics. Biological Psychiatry: Cognitive Neuroscience and Neuroim-aging, 3, 454-462.
https://doi.org/10.1016/j.bpsc.2017.03.007
[70] Ersland, K.M., Skrede, S., Stansberg, C. and Steen, V.M. (2017) Subchronic Olanzapine Exposure Leads to Increased Expression of Myelination-Related Genes in Rat Fronto-Medial Cortex. Translational Psychiatry, 7, 1262.
https://doi.org/10.1038/s41398-017-0008-3
[71] Fang, F., Zhang, H., Zhang, Y., et al. (2013) Antipsychot-ics Promote the Differentiation of Oligodendrocyte Progenitor Cells by Regulating Oligodendrocyte Lineage Transcrip-tion Factors 1 and 2. Life Sciences, 93, 429-434.
https://doi.org/10.1016/j.lfs.2013.08.004
[72] Xu, H., Yang, H.J. and Li, X.M. (2014) Differential Effects of Antipsychotics on the Development of Rat Oligodendrocyte Precursor Cells Exposed to Cuprizone. European Archives of Psychiatry and Clinical Neuroscience, 264, 121-129.
https://doi.org/10.1007/s00406-013-0414-3