Evi1 governs Kdm6b-mediated histone demethylation to regulate the Laptm4b-driven mTOR pathway in hematopoietic progenitor cells
Qiong Wu, … , Jianxin Lyu, Zhijian Qian
Qiong Wu, … , Jianxin Lyu, Zhijian Qian
Published December 16, 2024
Citation Information: J Clin Invest. 2024;134(24):e173403. https://doi.org/10.1172/JCI173403.
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Research Article Hematology

Evi1 governs Kdm6b-mediated histone demethylation to regulate the Laptm4b-driven mTOR pathway in hematopoietic progenitor cells

Abstract

Ecotropic viral integration site 1 (EVI1/MECOM) is frequently upregulated in myeloid malignancies. Here, we present an Evi1-transgenic mouse model with inducible expression in hematopoietic stem/progenitor cells (HSPCs). Upon induction of Evi1 expression, mice displayed anemia, thrombocytopenia, lymphopenia, and erythroid and megakaryocyte dysplasia with a significant expansion of committed myeloid progenitor cells, resembling human myelodysplastic syndrome/myeloproliferative neoplasm–like (MDS/MPN–like) disease. Evi1 overexpression prompted HSPCs to exit quiescence and accelerated their proliferation, leading to expansion of committed myeloid progenitors while inhibiting lymphopoiesis. Analysis of global gene expression and Evi1 binding site profiling in HSPCs revealed that Evi1 directly upregulated lysine demethylase 6b (Kdm6b). Subsequently, Kdm6b-mediated H3K27me3 demethylation resulted in activation of various genes, including Laptm4b. Interestingly, KDM6B and LAPTM4B are positively correlated with EVI1 expression in patients with MDS. The EVI1/KDM6B/H3K27me3/LAPTM4B signaling pathway was also identified in EVI1hi human leukemia cell lines. We found that hyperactivation of the LAPTM4B-driven mTOR pathway was crucial for the growth of EVI1hi leukemia cells. Knockdown of Laptm4b partially rescued Evi1-induced abnormal hematopoiesis in vivo. Thus, our study establishes a mouse model to investigate EVI1hi myeloid malignancies, demonstrating the significance of the EVI1-mediated KDM6B/H3K27me3/LAPTM4B signaling axis in their maintenance.

Authors

Qiong Wu, Chunjie Yu, Fang Yu, Yiran Guo, Yue Sheng, Liping Li, Yafang Li, Yutao Zhang, Chao Hu, Jue Wang, Tong-chuan He, Yong Huang, Hongyu Ni, Zhiguang Huo, Wenshu Wu, Gang Greg Wang, Jianxin Lyu, Zhijian Qian

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Figure 6

Laptm4b is identified as a functional mediator of Evi1 through Kdm6b-mediated histone demethylation.

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Laptm4b is identified as a functional mediator of Evi1 through Kdm6b-med...
(A) Venn diagram showing the significantly H3K27me3-enriched genes in Lin–c-Kit+ cells from WT mice but not in Evi1-OE mice identified by CUT&RUN-seq analysis. (B) Venn diagram showing the overlap between H3K27me3-enriched genes in Lin–c-Kit+ cells from WT mice and the genes significantly upregulated in Lin–c-Kit+ cells from Evi1-OE mice. (C) Correlation between EVI1 (MECOM in the database) and LAPTM4B in MDS patients (GEO GSE114922). (D) RT-qPCR analysis for transcription level of LAPTM4B in cell lines as indicated. (E) IGV peak visualization of H3K27me3 on the promoter of Laptm4b in WT or Evi1-overexpressing Lin–c-Kit+ mouse BM cells by CUT&RUN-seq analysis. (F) ChIP-qPCR analysis indicates that Evi1 overexpression significantly inhibits H3K27me3 enrichment at the promoter region of Laptm4b in Lin–c-Kit+ mouse BM cells. n = 3 for each group. (G) ChIP-qPCR analysis indicates that KDM6B directly binds to the promoter region of LAPTM4B in both U937 and AML1 cells. n = 2 for each group. (H) ChIP-qPCR analysis showing the effect of GSK-J4 treatment on H3K27me3 enrichment at the promoter region of LAPTM4B in U937 and AML1 cells. n = 2 for each group. In C, P value was calculated by Spearman’s r correlation. In D and F–H, data are represented as mean ± SD, ordinary 1-way ANOVA with Dunnett’s multiple-comparison test. Data are representative of at least 2 independent experiments. ***P < 0.001.