The LSD1/KDM1A neuro-specific isoform regulates neuronal differentiation through H3K9 demethylation [Affymetrix]

During brain development, histone-modifying enzymes play an important role by orchestrating transcriptional programs that regulate neuronal maturation. Lysine-Specific Demethylase 1 (LSD1, also named as KDM1A) functions as a transcriptional repressor by removing methyl groups at lysine 4 of histone H3 (H3K4). In neurons, alternative splicing can include an additional exon (exon E8a) within LSD1 transcripts, generating a LSD1+8a neuro-specific isoform. We here report that LSD1+8a isoform does not have the intrinsic ability to demethylate H3K4. LSD1+8a functions as a co-activator on its target genes by removing H3K9 repressive histone marks. We identify the supervillin protein (SVIL) as a LSD1+8a interacting partner and demonstrate that SVIL protein regulates neuronal maturation by controlling LSD1+8a mediated H3K9 demethylation. Thus, our results show that alternative splicing provides a genius mechanism by which LSD1 isoforms can acquire a dual specificity (H3K9 vs H3K4) and therefore differentially control specific gene expression patterns during brain development. In order to find some LSD1+8a regulated genes at differentiated SH-SY5Y cell lines, we infected SH-SY5Y with control or LSD1+8a shRNA, then induced differentiation with RA and BDNF, (Retinoic acid (RA) (Sigma) was added at a final concentration of 10 μM the next day after plating. After 4 days, the cells were washed three times with PBS and incubated with 50 ng/mL of Brain Derived Neural Factor (BDNF) (Millipore) in serum-free medium for 3 days), we extracted RNA from BDNF induced SH-SY5Y cells for expression analysis.Duplicates were included for Affymetrix Human transcriptome version 2 array.