031-22 – Analysis of Cortical Neuron Viability in TrappC9 Knockout Mice

Lipid metabolism is integral for a cell’s survival as it maintains the levels of structural and functional lipids within the cell. Neutral lipids synthesised in the endoplasmic reticulum are transported in specialised organelles called lipid droplets (LDs). The recruitment of TRAPPII to the surface of budding LDs by its protein subunit TrappC9 is a key process in LD formation. Numerous studies have shown a link between TrappC9 mutations and multiple disease phenotypes, most commonly intellectual disability, microcephaly of post-natal onset, and a reduction in cortical white matter. The link between TrappC9 loss-of-function mutations and abnormal LD formation was investigated using TrappC9 knockout mice. Cortical neurons were cultured from KO mice and LDH cytotoxicity assays were performed to measure the level of cell death over time with and without oleic acid treatment, which induces the accumulation of LDs. An increase in cell death was observed from 0-12 hours after treatment, with an increase in the rate of cell death in KO mouse cells after 6 hours. Comparisons between KO and wild-type cells, as well as between control and test groups, were performed but no significant differences were found. The delayed increase in cell death in KO cells could correlate with the post-natal degradation of neurons in mutant TrappC9 pathologies. Further analysis is required to expand the sample size and comparisons with hippocampal tissue would be beneficial to future research.