Diverse epigenetic strategies interact to control epidermal differentiation.

Mulder KW, Wang X, Escriu C, Ito Y, Schwarz RF, Gillis J, Sirokmány G, Donati G, Uribe-Lewis S, Pavlidis P, Murrell A, Markowetz F, Watt FM.
Source: Nat Cell Biol
Publication Date: (2012)
Issue: 14(7): 753-63
Research Area:
Cancer Research/Cell Biology
Dermatology/Tissue Engineering
Stem Cells
Gene Expression
Basic Research
Molecular Biology
Cells used in publication:
Keratinocyte, (NHEK-Ad) human adult
Species: human
Tissue Origin: dermal
4D-Nucleofector® 96-well Systems
4D-Nucleofector® X-Unit
A 332 chromatin modifiers screen was performed by siRNA transfection into kertinocytes. Based on the result, a prediction model was developed in order to predict epigenetic factors involved in epidermal differentiation. These factors impact two functionally related gene sets. Primary keratinocytes were transfected using Lonza Nucleofector 96-well Shuttle System with the SF solution.
It is becoming clear that interconnected functional gene networks, rather than individual genes, govern stem cell self-renewal and differentiation. To identify epigenetic factors that impact on human epidermal stem cells we performed siRNA-based genetic screens for 332 chromatin modifiers. We developed a Bayesian mixture model to predict putative functional interactions between epigenetic modifiers that regulate differentiation. We discovered a network of genetic interactions involving EZH2, UHRF1 (both known to regulate epidermal self-renewal), ING5 (a MORF complex component), BPTF and SMARCA5 (NURF complex components). Genome-wide localization and global mRNA expression analysis revealed that these factors impact two distinct but functionally related gene sets, including integrin extracellular matrix receptors that mediate anchorage of epidermal stem cells to their niche. Using a competitive epidermal reconstitution assay we confirmed that ING5, BPTF, SMARCA5, EZH2 and UHRF1 control differentiation under physiological conditions. Thus, regulation of distinct gene expression programs through the interplay between diverse epigenetic strategies protects epidermal stem cells from differentiation.