Valdivia Pablo, Martin Matt, LeFew William R, Ross James, Houck Keith A, Shafer Timothy J
Axion Biosystems, Atlanta, GA, United States.
National Center for Computational Toxicology, ORD, US Environmental Protection Agency, United States.
Neurotoxicology. 2014 Sep;44:204-17. doi: 10.1016/j.neuro.2014.06.012. Epub 2014 Jul 2.
Spontaneous activity in neuronal cultures on microelectrode arrays (MEAs) is sensitive to effects of drugs, chemicals, and particles. Multi-well MEA (mwMEA) systems have increased throughput of MEAs, enabling their use for chemical screening. The present experiments examined a subset of EPA's ToxCast compounds for effects on spontaneous neuronal activity in primary cortical cultures using 48-well MEA plates. A first cohort of 68 compounds was selected from the ToxCast Phase I and II libraries; 37 were positive in one or more of 20 individual ToxCast Novascreen assays related to ion channels (NVS_IC), with the remainder selected based on known neuroactivity. A second cohort of 25 compounds was then tested with 20 originating from the ToxCast Phase I and II libraries (not hits in NVS_IC assays) and 5 known negatives from commercial vendors. Baseline activity (1h) was recorded prior to exposing the networks to compounds for 1h, and the weighted mean firing rate (wMFR) was determined in the absence and presence of each compound. Compounds that altered activity by greater than the weighted change of DMSO-treated wells plus 2SD were considered "hits". Of the first set of 68 compounds, 54 altered wMFR by more than the threshold, while in the second set, 13/25 compounds were hits. MEAs detected 30 of 37 (81.1%) compounds that were hits in NVS_IC assays, as well as detected known neurotoxicants that were negative in NVS_IC assays, primarily pyrethroids and GABAA receptor antagonists. Conversely, wMFR of cortical neuronal networks on MEAs was insensitive to nicotinic compounds, as only one neonicotinoid was detected by MEAs; this accounts for the bulk of non-concordant compounds between MEA and NVS_IC assays. These data demonstrate that mwMEAs can be used to screen chemicals efficiently for potential neurotoxicity, and that the results are concordant with predictions from ToxCast NVS_IC assays for interactions with ion channels.
微电极阵列（MEA）上神经元培养物中的自发活动对药物、化学物质和颗粒的影响敏感。多孔MEA（mwMEA）系统提高了MEA的通量，使其可用于化学筛选。本实验使用48孔MEA板检测了美国环保署（EPA）ToxCast化合物中的一个子集对原代皮质培养物中自发神经元活动的影响。从ToxCast第一阶段和第二阶段文库中选择了第一批68种化合物；37种在与离子通道相关的20种单独的ToxCast Novascreen检测（NVS_IC）中的一种或多种中呈阳性，其余的则根据已知的神经活性进行选择。然后测试了第二批25种化合物，其中20种来自ToxCast第一阶段和第二阶段文库（在NVS_IC检测中未命中），5种是来自商业供应商的已知阴性对照。在将网络暴露于化合物1小时之前记录基线活动（1小时），并在每种化合物不存在和存在的情况下确定加权平均放电率（wMFR）。活性改变大于二甲基亚砜处理孔的加权变化加2个标准差的化合物被视为“命中”。在第一批68种化合物中，54种改变的wMFR超过阈值，而在第二批中，25种化合物中有13种命中。MEA检测到在NVS_IC检测中命中的37种化合物中的30种（81.1%），以及在NVS_IC检测中呈阴性的已知神经毒剂，主要是拟除虫菊酯和GABAA受体拮抗剂。相反，MEA上皮质神经元网络的wMFR对烟碱类化合物不敏感，因为MEA仅检测到一种新烟碱类化合物；这解释了MEA和NVS_IC检测之间大部分不一致的化合物。这些数据表明，mwMEA可用于有效筛选具有潜在神经毒性的化学物质，并且结果与ToxCast NVS_IC检测对与离子通道相互作用的预测一致。
