GSE212083
NEUROD1 is critical for the initial cell identity determination and differentiation of the endocrine progenitors in the pancreas [CUT&Tag]
While diabetes incidence is gradually rising worldwide, novel therapeutical approaches are required in the search for a replacement of dysfunctional endocrine tissue, especially beta-cells. A promising potential lies in direct cellular reprogramming of similar cell types sharing common multipotent progenitors. With the knowledge of molecular mechanisms determining the endocrine cell fate commitment and endocrine lineage differentiation, other endocrine cells contained within the islets of Langerhans or closely related cells could be trans- or dedifferentiated either in situ or in vitro with their subsequent transplantation into the patient.  NEUROD1 is a transcription factor situated on the base of the gene regulatory network of the developing endocrine precursors, directly downstream of endocrine lineage master regulator NEUROG3. While NEUROG3 initiates a rapid cascade of chromatin reorganization in numerous bivalent promoters resulting in spatiotemporal gene expression leading to differentiation of all endocrine cell subtypes from pancreatic multipotent progenitors, the role of NEUROD1 has yet to be clarified. Notably, NEUROD1 can induce neuronal program through pioneering and chromatin remodelling in other cell types.  In this study, we performed advanced molecular and phenotypic analyses in early endocrine-specific Neurod1-deficient mouse model, including RNA and CUT&Tag sequencing and lightsheet microscopy, to gain insight into the NEUROD1-regulated transcription network driving endocrine lineage cell fate commitment. Besides a postnatal diabetic phenotype, disrupted endocrine differentiation and associated altered islet architecture, we observed an apparent elevation in the non-endocrine gene expression pattern and uncovered alterations in the epigenetic landscape of characteristic genes, specifically in the H3K4me3 and H3K27me3 distribution. Therefore, we provide evidence that NEUROD1 is critical player responsible for the establishment of the endocrine cell identity, which further affects endocrine development and may serve as a potent proendocrine reprogramming driver. Overall design: 5 biological samples pooled from 3 to 7 pancreata (biological replicates of 2 control, 2 mutant samples, and one pooled-sample from both for IgG antibody) were analyzed at age E15.5. Approximately 5 000 - 20 000 FACS-sorted  tdTomato+ endocrine cells per sample were used for CUT&Tag profiling, determining amplification cycles number. SNAP-CUTANA™ K-MetStat Panel was included as a spike-in component.