IRF2 is a master regulator of human keratinocyte stem cell fate

Abstract

Resident adult epithelial stem cells maintain tissue homeostasis by balancing self-renewal and differentiation. The stem cell potential of human epidermal keratinocytes is retained in vitro but lost over time suggesting extrinsic and intrinsic regulation. Transcription factor-controlled regulatory circuitries govern cell identity, are sufficient to induce pluripotency and transdifferentiate cells. We investigate whether transcriptional circuitry also governs phenotypic changes within a given cell type by comparing human primary keratinocytes with intrinsically high versus low stem cell potential. Using integrated chromatin and transcriptional profiling, we implicate IRF2 as antagonistic to stemness and show that it binds and regulates active cis-regulatory elements at interferon response and antigen presentation genes. CRISPR-KD of IRF2 in keratinocytes with low stem cell potential increases self-renewal, migration and epidermis formation. These data demonstrate that transcription factor regulatory circuitries, in addition to maintaining cell identity, control plasticity within cell types and offer potential for therapeutic modulation of cell function.

Interaction of the NRF2 and p63 transcription factors promotes keratinocyte proliferation in the epidermis

“…However, knockdown of NRF2 in exponentially growing, non-differentiated cells in 2D cultures did not further suppress proliferation of keratinocytes with p63 knockdown and also did not have an effect on proliferation of keratinocytes with normal p63 levels. This is in contrast to previous studies, which showed that CRISPR/Cas9-mediated deletion of NRF2 reduced proliferation of human keratinocytes with high stem cell potential ( 41 ). Therefore, NRF2 activity may be particularly relevant for proliferation of stem cells.…”

Core transcriptional regulatory circuitries in cancer

“…2b ) [ 43 ]. Further, either incorporation of experimentally derived TF footprints data (DNase I hypersensitive sites) or accessible regions from ATAC-seq (Assay for Transposase-Accessible Chromatin using sequencing) can improve the prediction of TF binding sites [ 2 , 27 , 44 – 46 ]. In addition to genomic occupancy and TF connectivity, regulatory readout of core TFs and their functional impact on cell behaviors are other fundamental aspects for CRC.…”

“…Top-scored CRC of chronic lymphocytic leukemia predicted PAX5, ETV6, and IRF2 as centralized regulators [ 27 ]. Other examples of enhancer/NFR-centric CRC network construction include gastrointestinal stromal tumors [ 82 , 86 ], multiple myeloma [ 44 ], and keratinocyte stem cells [ 46 ]. In addition, dbCoRC serves as a valuable database to explore H3K27ac/enhancer-centric core circuitries in over 230 samples including cervical adenocarcinoma, chronic myelogenous leukemia, colorectal cancer, diffuse large B-cell lymphoma, gastric cancer, small cell lung cancer, pancreatic cancer, and prostate cancer.…”

The Delivery of α1-Antitrypsin Therapy Through Transepidermal Route: Worthwhile to Explore

“…The mRNA was prepared from epiCS topically treated with 0.2 mg AAT or recAAT for 18 h. COX2, a highly inducible gene in response to a variety of pro-inflammatory agents and cytokines ( Wu, 1996 ), was not affected by recAAT but significantly lowered by human AAT ( Figure 6 ). Neither of AAT proteins showed an effect on the expression of transforming growth factor (TGF)-β1, a mediator of cell proliferation, differentiation, and extracellular matrix production ( Yamane et al., 2016 ) and SOD2, an anti-oxidant response gene ( Mercado et al., 2019 ). We also checked for the putative effect of AAT on the expression of sterol regulatory element-binding transcription factor 1 (SREBF1), known as sterol regulatory element-binding protein 1 (SREBP-1) that induces adaptive responses to various stresses to maintain membrane lipid composition and ensure cell survival ( Hagen et al., 2010 ).…”

“…Taken together, these above results support the notion that a topical application of AAT does not induce stress, which could induce inflammatory cytokine release. Likewise, the expression of highly inducible genes in response to pro-inflammatory insults, such as COX2 , SOD2 and TGFB1 genes ( Wu, 1996 ; Yamane et al., 2016 ; Mercado et al., 2019 ), was not stimulated by the topical application of AAT proteins. To the contrary, human AAT reduced COX2 gene expression relative to controls or epiCS treated with recombinant AAT.…”