Suppression of Sin3A activity promotes differentiation of pluripotent cells into functional neurons

Abstract

Sin3 is a transcriptional corepressor for REST silencing machinery that represses multiple neuronal genes in non-neuronal cells. However, functions of Sin3 (Sin3A and Sin3B) in suppression of neuronal phenotypes are not well characterized. Herein we show that Sin3A knockdown impedes the repressive activity of REST and enhances differentiation of pluripotent P19 cells into electrophysiologically active neurons without inducing astrogenesis. It is also found that silencing Sin3B induces neurogenesis of P19 cells with a lower efficiency than Sin3A knockdown. The results suggest that Sin3A has a more profound effect on REST repressive machinery for silencing neuronal genes in P19 cells than Sin3B. Furthermore, we show that a peptide inhibitor of Sin3A-REST interactions promotes differentiation of P19 cells into functional neurons. Observations made in studies using genetic deletion and a synthetic inhibitor suggests that Sin3A plays an important role in the repression of neuronal genes by the REST regulatory mechanism.

Zebrafish sin3b mutants are viable but have size, skeletal, and locomotor defects

“…) in the absence of Sin3b leads us to conclude that Sin3b is dispensable for Rest mediated transcriptional repression during early development. These findings are consistent with recent results that suggest that Sin3b has a minimal role in Rest repression in P19 cells (Halder et al, )…”

“…4) in the absence of Sin3b leads us to conclude that Sin3b is dispensable for Rest mediated transcriptional repression during early development. These findings are consistent with recent results that suggest that Sin3b has a minimal role in Rest repression in P19 cells (Halder et al, 2017) Sin3b regulates Na v -channel activity by directly binding to Na V channels and reduce the gating charge associated with sodium channel activation (Vega et al, 2013). Zebrafish Na v 1.6a mutants show diminished spontaneous and touch-evoked escape behaviors during development (Low et al, 2010).…”

Physical and functional interaction between SET1/COMPASS complex component CFP-1 and a Sin3 HDAC complex

“…Functions ascribed to Rpd3/Sin3 complexes are varied and appear to be context dependent. Although typically referred to as corepressor complexes due to the presence of a histone deacetylase subunit, Rpd3/Sin3 complexes have been associated with both activation and repression of gene expression (Cantor and David, 2017;Cheng et al, 2014;Halder et al, 2017;Lewis et al, 2016;Liu and Pile, 2016;Saha et al, 2016;Saunders et al, 2017;van Oevelen et al, 2008van Oevelen et al, , 2010. In addition, the yeast Rpd3/Sin3S complex has been shown to repress cryptic transcription initiation in transcribed regions and to suppress antisense transcription initiation at promoters (Carrozza et al 2005;Churchman and Weissman 2011).…”

Same agent, different messages: insight into transcriptional regulation by SIN3 isoforms

“…Mammalian SIN3 proteins also impact pluripotency. While both isoforms function in pluripotent P19 cells, SIN3A exhibits a higher degree of repression of neuronal gene activity as compared to SIN3B [ 64 ]. Knockdown of Sin3a resulted in decreased expression of REST [repressor element-1 (RE-1) silencing transcription factor] and consequently an increase in the level of neuronal markers, leading to the differentiation of P19 cells into neurogenic cells.…”