MTG16 regulates colonic epithelial differentiation, colitis, and tumorigenesis by repressing E protein transcription factors
Rachel E. Brown, … , Sarah P. Short, Christopher S. Williams
Rachel E. Brown, … , Sarah P. Short, Christopher S. Williams
Published May 3, 2022
Citation Information: JCI Insight. 2022;7(10):e153045. https://doi.org/10.1172/jci.insight.153045.
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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 7

MTG16-mediated protection from tumorigenesis is partially dependent on repression of E protein activity.

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MTG16-mediated protection from tumorigenesis is partially dependent on r...
(A) MTG16 expression in sporadic CRC (n = 482) compared with normal colon tissue (n = 41) by DESeq2 of TCGA raw counts generated by Rahman et al. (69). The lines within each box represent the mean, the bounds of the boxes represent the 25th to 75th percentiles, and the bounds of the whiskers represent the range of the data. All individual data points are shown. *Padj < 0.05 by DESeq2. (B) MTG16 expression in sporadic CRC (n = 47) and CAC (n = 17) tumors. MTG16 expression was normalized by DESeq2 and limma batch correction. The box extends from the lower to upper quartile values of the data, with a line at the median. The lower whisker is at the lowest datum above Q1 – 1.5*(Q3–Q1), and the upper whisker at the highest datum below Q3 + 1.5*(Q3–Q1), where Q1 and Q3 are the first and third quartiles. (C) Schematic of the AOM/DSS model in which mice are injected i.p. with AOM followed by 3 cycles of DSS-induced injury and recovery prior to sacrifice. (D–G) CAC severity in AOM/DSS-treated Mtg16T/T (T/T) versus WT mice assessed by (D) histologic injury-regeneration score (scoring system described in Supplemental Table 2), (E and F) tumor multiplicity, and (G) average tumor volume per mouse. (H) Average tumor position normalized to colon length (distance from anus/colon length × 100%) per mouse. (I) Individual tumors graphed by size versus distance from anus normalized to colon length. (J) Weight loss compared using repeated measures 2-way ANOVA (n = 26 WT, 25 Mtg16T/T, representative of 2 independent experiments). (K) Colon length measured at sacrifice. (L) Survival curves compared using log-rank (Mantel-Cox) test. (M) Percentage of tumors in each grade of dysplasia, evaluated by a pathologist blinded to genotype and compared by χ2 test. (D–F, G–I, and K–M) Data are pooled from 2 independent experiments with n = 35 WT, 26 Mtg16T/T remaining at sacrifice. *P < 0.05 by (D, F–H, and K) 2-tailed Mann-Whitney test or (I) least-squares regression. (N) Unsupervised hierarchical clustering of differentially expressed genes in Mtg16T/T versus WT (n = 3) distal colon tumors by RNA-Seq. Gene expression in individual samples is displayed by z score (normalized count).