1447-P: The Snd1 Coregulator Controls ß-Cell Function

Abstract

The main function of the pancreatic β-cell is glucose-stimulated insulin secretion (GSIS) which serves to maintain whole body glucose homeostasis. Under type 2 diabetic conditions, a subset of β-cells fail and lose expression of key transcription factors (TFs) required for GSIS. Among these TFs is Pdx1, which requires the recruitment of a distinct set of transcriptional coregulators to modulate its activity. Recently, Pdx1 has been shown, through and IP-Mass Spec approach, to interact with numerous coregulators, including Snd1 (Staphylococcal nuclease and Tudor domain-containing protein) , which has been shown to facilitate protein-protein interactions and transcriptional control through the recruitment of chromatin modifying enzymes. Here, we first confirmed Pdx1 and Snd1 interact in the rodent β-cell lines by Co-IP, and in primary mouse β-cells and human EndoC-βH1 β-cell lines using proximity ligation assay. Next, we utilized CRISPR-Cas9 technology to generate Snd1-deficient mouse β-cell lines (Snd1KO) . Bulk mRNA-sequencing performed on Control and Snd1KO β-cell lines identified numerous differentially expressed genes linked to insulin secretion and cell proliferation. WST-1 cell proliferation assays revealed impaired proliferation in Snd1KO cell lines and high-glucose stimulated insulin secretion was blunted in INS-1 832/13 cells following siRNA-mediated knockdown of Snd1. As Snd1 has been shown to facilitate protein-protein interactions in other tissues, we found Snd1 interacts with numerous nuclear enriched proteins in the β-cell by IP-Mass Spec, including Stat3, Pax6, Ruvbl2 and Trim28. Future efforts are underway to characterize how Snd1 interactions with these proteins impact gene expression in vitro. Moreover, the role of Snd1 in modulating gene expression and β-cell function in vivo is being evaluated in a novel β-cell-specific (Ins1-Cre) Snd1 knockout mouse model. Disclosure S.Kanojia: None. R.K.Davidson: None. J.Spaeth: None. N.Casey: None. Funding K01DK115633Wells Center/Pediatric startupCDMD Pilot feasibility grant