Cell-type-specific Brain Methylomes Profiled via Ultralow-input Microfluidics

Methylomic studies require substantial amounts of DNA samples and this restriction hinders applications involving scarce animal or patient samples with direct biomedical relevance. Here we report a microfluidics-based reduced representative bisulfite sequencing protocol, MIcrofluidic Diffusion-based RRBS (MID-RRBS), that permits methylomic profiling with sub-1 ng starting DNA. Using this technology, we studied DNA methylation in NeuN+ and NeuN- fractions isolated from mouse cerebellum, revealing cell-type specific methylomic patterns. We also studied the DNA methylation in NeuN+ nuclei isolated from clozapine or vehicle treated mouse frontal cortex. Overall design: We examined genome-wide DNA methylation profiles of GM12878 cell line (with starting DNA sample amounts in the range of 0.3-10 ng and of single cells), NeuN+ and NeuN- fractions from mouse cerebellum (with starting DNA sample amounts of 0.5 or 10 ng) using MID-RRBS. We generated RNA-seq data on NeuN+ and NeuN- nuclei from mouse cerebellum. We also included MID-RRBS and RNA-seq data obtained on homogenates from mouse cerebellum. Finally, we generated MID-RRBS and RNA-seq data on NeuN+ nuclei isolated from clozapine or vehicle treated mouse frontal cortex.