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 1

MTG16 is expressed in colonic secretory cells, and its deficiency alters secretory lineage allocation.

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MTG16 is expressed in colonic secretory cells, and its deficiency alters...
(A) MTG16 expression in cell populations generated from scRNA-Seq of normal human colon biopsies (discovery cohort, n = 35 samples, 30,374 cells) (validation cohort, Supplemental Figure 1A). (B) Mtg16 expression in scRNA-Seq of WT mouse colon (n = 3 mice, 3653 cells). Color gradient represents average Mtg16 expression level in each cell population. Dot size represents percentage of cells in each population expressing Mtg16. Uniform manifold approximation and projection plots are in Supplemental Figure 1B. (C) RNAscope in situ hybridization of Mtg16 and Muc2 in WT mouse colon. Scale bar = 50 μm. Goblet cells are outlined in the insets at right. (D–F) WT and Mtg16–/– mouse colon (n = 10 WT, 9 Mtg16–/–) stained for (D) goblet cells by PAS stain, (E) enteroendocrine cells by IHC for SYP, and (F) tuft cells by IHC for doublecortin-like kinase 1 (DCLK1). Representative images at left. SYP+ and DCLK1+ cells are indicated with white arrowheads. Scale bars = 100 μm. *P < 0.05, ****P < 0.0001, 2-tailed Mann-Whitney U test. (G and H) Volcano plots demonstrating differentially expressed genes in (G) proximal (n = 2 WT, 2 Mtg16–/–) and (H) distal (n = 4 WT, 4 Mtg16–/–) colonic epithelial isolates by RNA-Seq. Horizontal dashed line, Padj < 0.05 by DESeq2. Vertical dashed lines, fold change = 1.5. Dot colors: goblet-associated (blue), enteroendocrine-associated (EE-associated) (red), and secretory-associated (black) genes.