Project description:Patients with NEUROGENIN3 mutations have enteric endocrinopathy and diabetes mellitus. We generated pluripotent stem cells from a patient’s fibroblasts to investigate if gene editing restores endocrine differentiation. Corrected cell lines differentiated into all pancreatic lineages while native cell lines failed to activate pancreatic progenitor and lineage determination genes, suggesting that the mutation disrupts pancreatic organogenesis and results in endocrine and exocrine dysfunction. Clinical testing revealed the patient has exocrine pancreatic insufficiency. These results expose a novel role for NEUROGENIN3 in human pancreatic differentiation and illustrates how patient-specific stem cells can be used to interrogate disease etiology and affect patient care.
Project description:Despite this critical role in islet cell development, the precise function and downstream genetic programs regulated directedly by NEUROG3 remain elusive. We therefore mapped genome-wide NEUROG3 occupancy in human induced pluripotent stem cell (iPSC)-derived endocrine progenitors and determined NEUROG3 dependency of associated genes to uncover direct targets. To this aim, we generated a novel hiPSC line (NEUROG3-HA-P2A-Venus), where NEUROG3 is HA-tagged and fused to a self-cleaving fluorescent VENUS reporter. We used the CUT&RUN technique, an alternative method to CHIP-seq allowing transcription factor profiling from a low cell number, to map NEUROG3 occupancy and epigenetic marks in pancreatic endocrine progenitors (PEP) differentiated from this hiPSC line. To optimize the stringency and relevance of NEUROG3 binding sites, we focused our analysis on regions identified both with HA and NEUROG3 antibodies and integrated NEUROG3 occupancy data with chromatin status and gene expression in PEPs and their NEUROG3-dependence. Mapping of NEUROG3 genome occupancy in PEPs uncovers an unexpectedly broad, direct control of the endocrine gene regulatory network (GRN) and raises novel hypotheses on how this master regulator controls islet and beta cell differentiation.
Project description:Despite this critical role in islet cell development, the precise function and downstream genetic programs regulated directedly by NEUROG3 remain elusive. We therefore mapped genome-wide NEUROG3 occupancy in human induced pluripotent stem cell (iPSC)-derived endocrine progenitors and determined NEUROG3 dependency of associated genes to uncover direct targets. To this aim, we generated a novel hiPSC line (NEUROG3-HA-P2A-Venus), where NEUROG3 is HA-tagged and fused to a self-cleaving fluorescent VENUS reporter. We used the CUT&RUN technique, an alternative method to CHIP-seq allowing transcription factor profiling from a low cell number, to map NEUROG3 occupancy and epigenetic marks in pancreatic endocrine progenitors (PEP) differentiated from this hiPSC line. To optimize the stringency and relevance of NEUROG3 binding sites, we focused our analysis on regions identified both with HA and NEUROG3 antibodies and integrated NEUROG3 occupancy data with chromatin status and gene expression in PEPs and their NEUROG3-dependence. Mapping of NEUROG3 genome occupancy in PEPs uncovers an unexpectedly broad, direct control of the endocrine gene regulatory network (GRN) and raises novel hypotheses on how this master regulator controls islet and beta cell differentiation.
Project description:Analysis of FACS-sorted intestinal Neurog3+/+ and Neurog3+/- cells from Neurog3 fluorencent reporter mice carrying two-(+/+) or one- (+/-) Neurog3 alleles. In the intestine, Neurog3 is an enteroendocrine (EE) lineage determinating transcription factor that transiently expressed in early EEC progenitors. By comparison the molecular profiles of Neurog3+/+ and Neurog3+/- cells, we hypothesized that Neurog3 gene dosage regulates the allocation of EE progenitor fates towards EEC vs. goblet cells.
Project description:Human embryonic stem cells with one allele of the NEUROG3 gene genetically modified into a fusion gene NEUROG3-LINKER-TAGRFPT-P2A-EGFP-NLS were differentiated into the pancreatic lineage until Stage 4 Day 1 of the in vitro differentiation protocol (Rezania et al., 2014, as modified in Petersen et al., 2017). GFP positive and negative cells were FAC-sorted according to their cell cycle state (G0/G1 or G2M), and the global transcriptomes of these four groups were compared using bulk RNA-seq.
Project description:To better understand the mechanism by which HES1 regulates pancreas development we took advantage of recent developments in directed differentiation of human embryonic stem cells (hESCs) to the pancreatic endocrine lineage via a series of progenitor stages (Figure 1 and (Rezania et al., 2014). Using the iCRISPR platform (González et al., 2014), we introduced indels in the HES1 and NEUROG3 genes, either singly or in combination in iCRISPR H1 cells. Using previously described gRNAs (Zhu et al., 2016) to target exon2 of the NEUROG3 gene and exon2 of the HES1 gene we detected by Sanger and RNA-sequencing a 2 bp insertion and a T insertion, respectively, resulting in premature STOP codons in two/multiple clonal cell lines carrying the introduced mutation and the loss of NEUROG3 by immunostaining We then subjected two or more clonal lines of H1-iCRISPR (wildtype), HES1−/−, NEUROG3−/− and HES1−/−NEUROG3−/− (abbreviated H1N3-dKO or H1−/−N3−/−) to differentiation to β-like cells using a modified version of the protocol from Rezania et al. (2014). Marker analysis showed that all cell lines maintained pluripotency (OCT4+) as hESC and were able to differentiate to FOXA2+ and SOX17+ co-positive definitive endoderm (DE, Day 3), PDX1+ cells at the posterior foregut stage (PF, Day 7), to bipotent progenitors marked by PDX1+ and NKX6-1+ at the Pancreatic Endoderm stage (PE, Day 10), and the Endocrine Precursor stage (EP, Day 13)
Project description:Since loss of Hes1 and Notch signalling drives progenitors to the endocrine lineage, we set up a pancreas explant system with crosses of heterozygous Neurog3tTA/+, a knock-in allele which makes the homozygote Neurog3tTA/tTA embryos deficient in Neurog3 (hereafter Neurog3-null). Hereby endocrine differentiation is impeded and we can study the Neurog3-independent role of Notch signalling by DAPT inhibition of γ-secretase. E12.5 wildtype and Neurog3-null pancreata were explanted on fibronectin, grown for 3 days, and then treated with vehicle control (0.1% DMSO) or DAPT for 24h. RNA was isolated and subjected to Agilent microarray analysis
Project description:Human embryonic stem cells with one allele of the NEUROG3 gene genetically modified into a fusion gene NEUROG3-LINKER-TAGRFPT-P2A-EGFP-NLS were differentiated into the pancreatic lineage until Stage 4 Day 1 of the in vitro differentiation protocol (Rezania et al., 2014, as modified in Petersen et al., 2017). The cells were index-sorted according to their GFP expression to enrich for low GFP and high GFP cells, and deep single-cell RNA-seq was performed using the plate-based Smart-seq2 platform (Picelli et al. 2014).
Project description:Pancreatic beta cell generation from induced pluripotent stem cells (iPSCs) offers an alternative donor tissue source; however, the efficiency of induction of INSULIN (INS)+ cells from human iPSCs (hiPSCs) is low. We aimed to establish an efficient differentiation protocol for generating INS+ cells from hiPSCs by identifying novel inducers. We screened small molecules that increased the induction rate of INS+ cells from hiPSC-derived PDX1+ pancreatic progenitor cells by using high-throughput screening (HTS) system. We identified one compound, sodium cromoglicate (SCG) out of about 1,250 small molecules that we screened. When SCG was combined with the previously described protocol, the induction rate of INS+ cells increased up to 15–20%, and the cells developed the ability to secrete C-peptide in vitro. We found that SCG facilitates the differentiation of multiple endocrine cell types, including INS+ cells, in both hiPSC differentiation cultures and mouse embryonic pancreas explants by inducing NEUROG3+ endocrine precursor cells. We also confirmed that the mechanisms of action by which SCG induces the pancreatic endocrine differentiation include the inhibition of BMP4 signaling.
Project description:Atoh8 is a transcription factor of the basic-helix-loop-helix (bHLH) family that is expressed in multiple tissues during embryonic development but whose specific functions remain unknown. The gene encoding Atoh8 is induced by various lineage- determining bHLH transcription factors in cell culture, suggesting a possible common role of this gene in multiple bHLH-driven differentiation programs. In the pancreas, the pro-endocrine bHLH factors Neurogenin3 (Neurog3) and NeuroD1 activate Atoh8 expression. Moreover, Atoh8 is expressed in the embryonic pancreas confirming its participation in the pancreatic transcriptional cascade. This work aims at gaining insight into the molecular function of Atoh8 during the endocrine differentiation program initiated by Neurog3 in the pancreas. To this aim, we have generated a recombinant adenovirus encoding an Atoh8-specific shRNA (Ad-shAtoh8) and used it to down-regulate expression of the Atoh8 gene in Neurog3-expressing pancreatic ductal cells (mPAC), a cellular model of endocrine cell differentiation. Thus, we have compared global changes in gene expression profiles between cells treated with Ad-Neurog3+shControl and cells treated with Ad-Neurog3+shAtoh8 using Affymetrix microarrays. Our results show that Atoh8 silencing significantly affects the expression of 293 genes in Neurog3-expressing mPAC cells. Gene Ontology analysis has revealed cell cycle as the biological function most significantly represented among the modified genes. These results uncover a potential function of Math6 as a regulator of cell cycle progression and provide novel insights into the link between Neurog3 and the regulation of the cell cycle.