Molecular Horizons Seminar - Professor Orna Elroy-Stein

Astrocytes, the predominant glial cells in the central nervous system (CNS), support neuronal function and play crucial roles in maintaining brain homeostasis. Astrocytes are central to Vanishing White Matter (VWM) disease, a rare neurodegenerative disorder characterised by white matter loss in the CNS due to mutations in eIF2B, a critical factor of mRNA translation.

To define the genes mainly regulated at the translation level, we analysed the expression strategies used by astrocytes upon their activation in response to cytokines stimuli. While optimising the protocol for polysome extraction, we discovered that most translating ribosomes within astrocytes are linked to cell membranes, unlike other cell types. Once we succeeded in efficiently extracting the polysomes, we used primary astrocytes isolated from the brains of WT and eIF2BR132H/R132H mice (serving as our model for VWM disease) for ribosome profiling (Ribo-seq) and RNA sequencing (RNA-seq) at different time points along cytokine-induced activation.

The combined analyses of the data revealed that 30% of the genes are regulated at the level of translation efficiency; and that the eIF2B-mutant astrocytes lost their ability to execute the translation regulation programs properly. The involved genes and expression networks offer targets for developing therapeutic modalities. Moreover, RNA-seq/Ribo-seq approach provides a powerful molecular tactic for the initial evaluation of potential drugs.