GSE123136
SUFU and SPOP mediated downregulation of Hh signaling promotes pancreatic beta-cell differentiation through the regulation of organ-specific stromal niche signals
Purpose: Human Embryonic Stem Cell (hESC)-derived insulin-producing beta cells offer a promising cell-based therapy for diabetes. However, efficient hESC to beta cell differentiation has proven difficult, possibly due to the lack of cross-talk with the appropriate mesenchymal niche. To define organ-specific niche signals, we isolated pancreatic and gastrointestinal stromal cells and analyzed their transcriptomes during development. Methods: mRNA profiles from E13.5 mice were generated from mesenchymal cells dissected from wild-type (WT)  intestine, stomach, pancreas and mutant Sufu-/- Spop -/- pancreatic mesenchyme, in duplicate, by illumina HiSeq 2500. Reads were aligned to the mm10 assembly and unambiguously mapping reads were analyzed at the gene level for differential expression between tissue types alignment using STAR and differential analysis using DESeq2. Results: Using our workflow, we mapped about 30 million reads per sample to mm10. Differential expression (DE) analysis identified over 900 significantly differentially expressed genes between WT pancreatic mesenchyme and gastrointestinal mesenchymes, and over 1100 genes differentially expressed between WT and mutant pancreatic mesenchyme. Our findings reveal the importance of tightly-regulated Hh signaling in the pancreatic mesenchyme. In vivo inactivation of mesenchymal Hh signaling leads to annular pancreas, and stroma-specific activation of Hh signaling via loss of Hh  regulators, Sufu and Spop, impairs pancreatic growth and beta cell genesis. Genetic rescue and transcriptome analyses show that these Sufu and Spop knockout defects occur through GLI2-mediated activation of gastrointestinal stromal signals such as Wnt ligands. Importantly, inhibition of Wnt signaling in organoid and hESC cultures significantly promotes insulin-producing cell generation, revealing the requirement for organ-specific regulation of stromal niche signals. Overall design: mRNA profiles from E13.5 mice were generated from mesenchymal cells dissected from wild-type (WT)  intestine, stomach, pancreas and mutant Sufu-/- Spop -/- pancreatic mesenchyme, in duplicate, by Illumina HiSeq 2500