Preclinical stroke trial with the PARP inhibitor veliparib

Parthanatos是一种细胞死亡信号传导途径，其中对DNA的过度氧化损伤导致聚（ADP-核糖）聚合酶（PARP）的过度活化，然后刺激大的聚（ADP-核糖）聚合物的形成，所述大的聚（ADP-核糖）聚合物诱导凋亡诱导因子（AIF）从线粒体外膜释放。在胞质溶胶中，AIF与巨噬细胞迁移抑制因子（MIF）形成复合物，该复合物易位到细胞核中，在细胞核中MIF降解DNA并产生细胞死亡。文献综述显示了23篇支持parthanatos在短暂性和永久性大脑中动脉闭塞（MCAO）的年轻雄性小鼠和大鼠中发挥作用的出版物，这些出版物基于来自13个不同实验室的9种不同PARP抑制剂（19项研究）或PARP 1缺失小鼠（6项研究）的使用。几项研究表明MCAO后4-6小时为治疗窗口。在年轻雌性大鼠中，来自2个实验室的2项研究基于使用2种不同PARP抑制剂支持parthanatos的作用，而来自1个实验室的2项研究不支持parthanatos在年轻雌性PARP 1无效小鼠中的作用。除了parthanatos介导的神经元细胞死亡之外，大量文献表明PARP抑制剂可以通过干扰小胶质细胞中的NFkB转录、抑制MMP- 9释放以及限制血脑屏障损伤和出血性转化来减少神经炎症。总体而言，大多数文献强烈支持PARP抑制剂具有神经保护作用的科学前提，即使在MCAO后再灌注时给予。然而，没有MCAO的研究已经测试了PARP抑制剂在已知具有衰老的免疫系统和性激素保护减弱的老年动物中。由于老年动物被认为与人类卒中人群更相关，因此在进入临床卒中试验之前，应在两种性别的老年动物中测试PARP抑制剂。我们建议在老年雄性和雌性小鼠中在MCAO后再灌注时测试PARP抑制剂veliparib，这是基于其良好的脑渗透性及其在人类肿瘤学试验中确定的安全性。我们计划的主要结果是一个月的表现达到抓灵巧任务已知显示持续赤字超过一个月后中风。次要结果包括其他四项感觉运动任务的短期缺陷，一个月时的恐惧条件认知，一个月时的脑萎缩，以及病变体积、CBF和DTI与组织pH图不匹配的急性MRI测定。该团队由一位在MCAO临床前研究方面拥有30年经验的PI领导，神经科学家在兴奋性毒性和中风模型中阐明了parthanatos信号传导，中风临床医生在中风后的小鼠神经行为测试方面具有专业知识，MR科学家在开发用于中风和其他疾病的脑成像新模式方面拥有25年经验，以及一位擅长啮齿动物多模态MR成像的MR科学家。该团队在实验性中风方面有着长期的合作历史，并高度致力于SPAN使命的科学严谨性，作为缺血性中风再灌注治疗辅助使用的六种候选药物的测试中心。

Parthanatos is a cell death signaling pathway in which excessive oxidative damage to DNA leads to over- activation of poly(ADP-ribose) polymerase (PARP), which then stimulates the formation of large poly(ADP- ribose) polymers that induce the release of apoptosis-inducing factor (AIF) from the outer mitochondrial membrane. In the cytosol, AIF forms a complex with macrophage migration inhibitory factor (MIF) that translocates into the nucleus where the MIF degrades DNA and produces cell death. A review of the literature reveals 23 publications that support a role for parthanatos in young male mice and rats subjected to transient and permanent middle cerebral artery occlusion (MCAO) based on the use of 9 different PARP inhibitors (19 studies) or PARP1 null mice (6 studies) from 13 different labs. Several studies indicate a therapeutic window of 4-6 h after MCAO. In young female rats, 2 studies from 2 labs support a role for parthanatos based on the use of 2 different PARP inhibitors, whereas 2 studies from one lab do not support a role in young female PARP1 null mice. In addition to parthanatos-mediated neuronal cell death, a body of literature indicates that PARP inhibitors can reduce neuroinflammation by interfering with NFkB transcription in microglia, suppressing MMP- 9 release, and limiting blood-brain barrier damage and hemorrhagic transformation. Overall, most of the literature strongly supports the scientific premise that a PARP inhibitor is neuroprotective, even when it is given at reperfusion after MCAO. However, no studies of MCAO have tested PARP inhibitors in aged animals known to have a senescent immunologic system and diminished protection by sex hormones. Because aged animals are thought to be more translationally relevant for the human stroke population, a PARP inhibitor should be tested in aged animals of both sexes before moving into clinical stroke trials. We propose testing the PARP inhibitor veliparib at reperfusion after MCAO in aged male and female mice based on its good brain penetration and its established safety in human oncology trials. Our planned primary outcome is one-month performance on a reaching-to-grasp dexterity task known to display sustained deficits for over a month after stroke. Secondary outcomes include short-term deficits in four other sensorimotor tasks, fear conditioning cognition at one month, brain atrophy at one month, and acute MRI determinations of lesion volume, CBF, and mismatch of DTI with tissue pH maps. The team is led by a PI with 30 years of experience in performing preclinical studies of MCAO, neuroscientists who elucidated parthanatos signaling in models of excitotoxicity and stroke, a stroke clinician with expertise in neurobehavior testing in mice after stroke, an MR scientist with 25 years of experience in developing new modalities of brain imaging for use in stroke and other disorders, and a MR scientist with expertise in multimodal MR imaging in rodents. The team has a long history of collaborating together on experimental stroke and is highly dedicated to the scientific rigor of the SPAN mission by serving as a test site for six candidate drugs for adjunct use with reperfusion therapies in ischemic stroke.