Spinal cord microglia were isolated via a Percoll gradient Sequencing was performed by the High Throughput Genomics Group at the Wellcome Trust Centre for Human Genetics (Oxford University). ChIP-seq libraries were prepared on the automated Wafergen’s Apollo Prep system using a PrepX ILMN 32i 96 sample library kit (400076, Wafergen Biosystems). Libraries were prepared together to avoid batch effects. Custom adaptor and barcode tags were used (5'- P-GATCGGAAGAGCGGTTCAGCAGGAATGCCGAG, 5’-ACACTCTTTCCCTACACGACGCTCTTCCGATCT). Samples were amplified (18 cycles for ChIP) and multiplexed in replicate flow cells on an Illumina HiSeq2500 platform to yield 50bp paired-end reads at a depth of at least 40M.