MTG16 regulates colonic epithelial differentiation, colitis, and tumorigenesis by repressing E protein transcription factors
Rachel E. Brown, Justin Jacobse, Shruti A. Anant, Koral M. Blunt, Bob Chen, Paige N. Vega, Chase T. Jones, Jennifer M. Pilat, Frank Revetta, Aidan H. Gorby, Kristy R. Stengel, Yash A. Choksi, Kimmo Palin, M. Blanca Piazuelo, Mary Kay Washington, Ken S. Lau, Jeremy A. Goettel, Scott W. Hiebert, Sarah P. Short, Christopher S. Williams
Rachel E. Brown, Justin Jacobse, Shruti A. Anant, Koral M. Blunt, Bob Chen, Paige N. Vega, Chase T. Jones, Jennifer M. Pilat, Frank Revetta, Aidan H. Gorby, Kristy R. Stengel, Yash A. Choksi, Kimmo Palin, M. Blanca Piazuelo, Mary Kay Washington, Ken S. Lau, Jeremy A. Goettel, Scott W. Hiebert, Sarah P. Short, Christopher S. Williams
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Research Article Cell biology Gastroenterology

MTG16 regulates colonic epithelial differentiation, colitis, and tumorigenesis by repressing E protein transcription factors

Abstract

Aberrant epithelial differentiation and regeneration contribute to colon pathologies, including inflammatory bowel disease (IBD) and colitis-associated cancer (CAC). Myeloid translocation gene 16 (MTG16, also known as CBFA2T3) is a transcriptional corepressor expressed in the colonic epithelium. MTG16 deficiency in mice exacerbates colitis and increases tumor burden in CAC, though the underlying mechanisms remain unclear. Here, we identified MTG16 as a central mediator of epithelial differentiation, promoting goblet and restraining enteroendocrine cell development in homeostasis and enabling regeneration following dextran sulfate sodium–induced (DSS-induced) colitis. Transcriptomic analyses implicated increased Ephrussi box–binding transcription factor (E protein) activity in MTG16-deficient colon crypts. Using a mouse model with a point mutation that attenuates MTG16:E protein interactions (Mtg16P209T), we showed that MTG16 exerts control over colonic epithelial differentiation and regeneration by repressing E protein–mediated transcription. Mimicking murine colitis, MTG16 expression was increased in biopsies from patients with active IBD compared with unaffected controls. Finally, uncoupling MTG16:E protein interactions partially phenocopied the enhanced tumorigenicity of Mtg16–/– colon in the azoxymethane/DSS-induced model of CAC, indicating that MTG16 protects from tumorigenesis through additional mechanisms. Collectively, our results demonstrate that MTG16, via its repression of E protein targets, is a key regulator of cell fate decisions during colon homeostasis, colitis, and cancer.

Authors

Rachel E. Brown, Justin Jacobse, Shruti A. Anant, Koral M. Blunt, Bob Chen, Paige N. Vega, Chase T. Jones, Jennifer M. Pilat, Frank Revetta, Aidan H. Gorby, Kristy R. Stengel, Yash A. Choksi, Kimmo Palin, M. Blanca Piazuelo, Mary Kay Washington, Ken S. Lau, Jeremy A. Goettel, Scott W. Hiebert, Sarah P. Short, Christopher S. Williams

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Figure 5

Mtg16 is upregulated in experimental colitis and patients with IBD and is required for ASCL2-mediated colonic epithelial regeneration.

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Mtg16 is upregulated in experimental colitis and patients with IBD and ...
(A) MTG16 expression from an RNA-Seq data set generated from rectal biopsies of treatment-naive pediatric UC patients (n = 206) versus unaffected controls (n = 20) in the PROTECT study (58). Transcript counts were normalized by DESeq2. ****Padj < 0.0001 by DESeq2. (B) MTG16 expression in an RNA-Seq data set from adult UC patients with active disease (n = 14), UC patients in remission (n = 14), and unaffected control patients (n = 16) (60). Transcript counts were normalized by DESeq2. **Padj < 0.01 and ****Padj < 0.0001 by pairwise DESeq2. (C) MTG16 expression in a microarray data set comparing UC (n = 5), Crohn’s colitis (n = 20), and unaffected (n = 8) patient biopsies (61). **Padj < 0.01 and ****Padj < 0.0001 by limma in GEO2R. Normalized probe intensity is plotted for data visualization. (A–C) The lines within each box represent the mean, the bounds of the boxes represent 25th to 75th percentiles, and the bounds of the whiskers represent the range of the data. All data points are shown. (D) Schematic of the DSS injury-regeneration model in which mice are treated with 2% for 5 days followed by 4 days of recovery. (E) Volcano plot demonstrating significantly downregulated (blue) and upregulated (red) genes in distal colon crypt isolates from WT mice following DSS-induced injury and regeneration compared with baseline (n = 3). Horizontal dashed line indicates Padj < 0.05 by DESeq2. Vertical dashed lines indicate fold change = 2. (F) ASCL2 occupancy near an Mtg16 transcription start site (TSS 2) in a ChIP-Seq data set of FACS-sorted Ascl2+ regenerating cells compared to Lgr5+ homeostatic CBCs generated by Murata et al. (2). Scale: 0–800. (G) GSEA plot demonstrating significant enrichment of the Ascl2+ dedifferentiating cell signature (Supplemental Tables 3 and 4 and citation in the supplement) in distal colon crypt isolates from WT mice following DSS-induced colitis versus WT mice at baseline (n = 3). (H–K) GSEA performed on RNA-Seq of Mtg16–/– versus WT distal colon crypt isolates following DSS injury-regeneration (n = 3 WT, 4 Mtg16–/–) using (H and I) epithelial regeneration-associated gene sets and (J and K) gene sets representing E protein transcriptional signatures (Supplemental Tables 3 and 4 and citations in the supplement). (G–K) Tag %, the percentage of gene hits before (for positive ES) or after (for negative ES) the peak in the running ES, indicating the percentage of genes contributing to the ES. FDR q < 0.05 is considered significant.