A test strategy to detect toxicants and developmental toxicants that affect human neuronal processes

Abstract

We performed an extensive literature search to select a list of highly relevant test compounds of known toxicity, developmental neurotoxicity or proven absence of toxicity. We used conditionally-immortalized human neural precursor cells (LUHMES cells) as test system. They were differentiated within 5 days to a homogeneous population with a complex neurite network and typical biochemical and morphological features of dopaminergic neurons, when GDNF and cAMP were added to the medium. The toxicity of the compounds for developed cells was assessed using conventional cytotoxicity assays based on the metabolic capacity of the cells and their cell membrane integrity.Additionally, more advanced endpoints like neurite mass, mitochondrial mass, nuclear condensation and cell number were analysed, using high content analysis methods. These endpoints were measured with the objective of establishing more sensitive and in case of the neurite mass also more neuronal specific endpoints. In order to identify compounds which exhibit a neuronal developmental specific toxicity, the compounds were tested during various developmental phases. IC50 values obtained thereby were then plotted against each other. Based on these plots potentially neurotoxic and developmental neurotoxic compounds were identified. Based on the IC50 values in the different systems, and additional data from primary cells and simple cell lines, toxicity profiles of the different compounds can be established.