Genome-wide maps of histone H3K9/K14 acetylation state in HeLa cells control (Mock) or silenced for Gb3 globoside synthase (Gb3S_KD) or silenced for the epigenetic modulator AUTS2 (AUTS2_KD)

Glycosphingolipid metabolism is reprogrammed during neural development with a switch from globo to ganglio-series glycosphingolipids production. We discovered that globo-series glycosphingolipids repress the epigenetic regulator of neuronal genes expression AUTS2. AUTS2 in turn, binds and activates the promoter of the first and rate limiting ganglioside producing enzyme GM3 synthase, thus fostering the synthesis of gangliosides. By this mechanism the globo-AUTS2 axis controls glycosphingolipid reprogramming and neural genes expression during neural differentiation, which involves this circuit in neurodevelopment and its defects in neuropathology. We report Gb3 globoside suppresses the expression of the epigenetic modulator AUTS2. The silencing of Gb3 synthase in HeLa cells induces the thepletion of Gb3 globoside, consequentially promoting AUTS2 expression. AUTS2 in turn, binds and activates the promoter of the target genes promoting local histone hyperacetylation and gene expression. Thus, the globo-series glycosphingolipids, by counteracting the expression of AUTS2, decrease histone acetylation at neuronal gene promoters repressing their transcription in HeLa cells. Overall design: HeLa cells were silenced for 72 hours with 120pmol of specific siRNA. Chromatin immunoprecipitation was performed with antibody anti-acetyl H3K9/K14 (Millipore 06-599). Immunoprecipitated chromatin was purifyed and analyzed by next-generation sequencing.