Aging of myelinating glial cells predominantly affects lipid metabolism and immune response pathways

In order to uncover the biological processes affected in glial cells by aging, we analyzed microarray gene expression of the Schwann cell-rich mouse sciatic nerve at 17 time-points throughout life, from day of birth until senescence. In addition, we combined these data with the microarray gene expression data of myelin 56 day-old mouse mutants carrying deletions of either Pmp22, SCAP or Lpin1. Seven mice were dissected per developmental or aging time-point. Both sciatic nerves were isolated from each mouse and tissues were pooled per time-point to extract total RNA. For the mutants and their wild-type littermates, sciatic nerves were dissected from three mice per genotype. Tissues were not pooled, which generated triplicates per genotype. Total RNA was extracted, purified and quality-controlled. For each condition, 300 ng of total RNA was used to synthesize cRNA using the Illumina TotalPrep RNA amplification kit (Ambion). The cRNA was then quantified, quality controlled and hybridized to the MouseWG-6 v1 expression Beadchips (Illumina) according to the manufacturer’s instructions.