Neurog3-Independent Methylation Is the Earliest Detectable Mark Distinguishing Pancreatic Progenitor Identity

Abstract

Summary In the developing pancreas, transient Neurog3-expressing progenitors give rise to four major islet-cell types, α, β, δ, and γ; when and how the Neurog3+ cells choose cell-fate is unknown. Using single-cell RNAseq, trajectory analysis, and combinatorial lineage tracing, we showed here that the Neurog3+ cells co-expressing Myt1 (i.e., Myt1+Neurog3+) were biased towards β-cell fate; while those not simultaneously expressing Myt1 (Myt1-Neurog3+) favored α-fate. Myt1 manipulation only marginally affected α- vs. β-cell specification, suggesting Myt1 as a marker but not determinant for islet-cell type specification. The Myt1+Neurog3+ cells displayed higher Dnmt1 expression and enhancer methylation at Arx, an α-fate-promoting gene. Inhibiting Dnmts in pancreatic progenitors promoted α-cell specification, while Dnmt1 over-expression or Arx enhancer hyper-methylation favored β-cell production. Moreover, the pancreatic progenitors contained distinct Arx enhancer methylation states without transcriptionally definable sub-populations, a phenotype independent of Neurog3 activity. These data suggest that Neurog3-independent methylation on fate-determining gene-enhancers specifies distinct endocrine-cell programs.

Comprehensive single cell mRNA profiling reveals a detailed roadmap for pancreatic endocrinogenesis

“…7F). This finding is in line with a recent study showing that Ngn3 + cells that express Myt1 are biased toward β-cell fate (Liu et al, 2019). The balance between the expression of Arx and Pax4 is the only currently known mechanism of endocrine cell subtype specification (Collombat et al, 2003(Collombat et al, , 2009.…”

RETRACTED: Roles of Epigenetic Modifications in the Differentiation and Function of Pancreatic β-Cells

“…Therefore, in current cell replacement therapy research, endogenous alpha cells are considered to be important for β cell reprogramming. Recent studies have also shown that inhibiting DNA methylation in pancreatic progenitor cells promotes alpha cell production (Liu et al, 2019 ). In addition, the hypermethylation of CpG islands can reduce the expression of HNF4α gene and affect the differentiation of pancreatic β cells (Gilbert and Liu, 2012 ).…”

Understanding generation and regeneration of pancreatic β cells from a single-cell perspective

“…Several studies have provided evidence to support that the development and heterogeneity of EP cells are regulated at the chromatin level (Scavuzzo et al, 2018;Yu et al, 2018;Liu et al, 2019). Our work has uncovered a regulatory role of the histone demethylase Jmjd3 (also known as Kdm6b) during the EP cell transition (Yu et al, 2018).…”

“…Using scRNA-seq, we found that Jmjd3 only affects the efficiency of the cell fate transition from Ngn3-GFP low to Ngn3-GFP high but does not alter the transcriptomes and developmental pathways of Ngn3 high cells (Yu et al, 2018). Liu and colleagues have proposed that the EPs are transcriptionally uniform but epigenetically distinct (Liu et al, 2019). Using scRNAseq, the authors have shown that mouse Ngn3 + cells heterogeneously express Myt1, which encodes a TF involved in regulating endocrine islet cell differentiation and function (Wang et al, 2007(Wang et al, , 2008.…”