Browsing by Author "Lei, Ming"

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    Dbh+ catecholaminergic cardiomyocytes contribute to the structure and function of the cardiac conduction system in murine heart
    (Springer Nature, 2023-11-28) Sun, Tianyi; Grassam-Rowe, Alexander; Pu, Zhaoli; Li, Yangpeng; Ren, Huiying; An, Yanru; Guo, Xinyu; Hu, Wei; Liu, Ying; Zheng, Yuqing; Liu, Zhu; Kou, Kun; Ou, Xianhong; Chen, Tangting; Fan, Xuehui; Liu, Yangyang; Tu, Shu; He, Yu; Ren, Yue; Chen, Ao; Shang, Zhouchun; Xia, Zhidao; Miquerol, Lucile; Smart, Nicola; Zhang, Henggui; Tan, Xiaoqiu; Shou, Weinian; Lei, Ming; Pediatrics, School of Medicine
    The heterogeneity of functional cardiomyocytes arises during heart development, which is essential to the complex and highly coordinated cardiac physiological function. Yet the biological and physiological identities and the origin of the specialized cardiomyocyte populations have not been fully comprehended. Here we report a previously unrecognised population of cardiomyocytes expressing Dbhgene encoding dopamine beta-hydroxylase in murine heart. We determined how these myocytes are distributed across the heart by utilising advanced single-cell and spatial transcriptomic analyses, genetic fate mapping and molecular imaging with computational reconstruction. We demonstrated that they form the key functional components of the cardiac conduction system by using optogenetic electrophysiology and conditional cardiomyocyte Dbh gene deletion models. We revealed their close relationship with sympathetic innervation during cardiac conduction system formation. Our study thus provides new insights into the development and heterogeneity of the mammalian cardiac conduction system by revealing a new cardiomyocyte population with potential catecholaminergic endocrine function.
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    Targeting MLL1 H3K4 methyltransferase activity in mixed-lineage leukemia
    (Elsevier, 2014-01-23) Cao, Fang; Townsend, Elizabeth C.; Karatas, Hacer; Xu, Jing; Li, Li; Lee, Shirley; Liu, Liu; Chen, Yong; Ouillette, Peter; Zhu, Jidong; Hess, Jay L.; Atadja, Peter; Lei, Ming; Qin, Zhaohui; Malek, Sami; Wang, Shaomeng; Dou, Yali; IU School of Medicine
    Here we report a comprehensive characterization of our recently developed inhibitor MM-401 that targets the MLL1 H3K4 methyltransferase activity. MM-401 is able to specifically inhibit MLL1 activity by blocking MLL1-WDR5 interaction and thus the complex assembly. This targeting strategy does not affect other mixed-lineage leukemia (MLL) family histone methyltransferases (HMTs), revealing a unique regulatory feature for the MLL1 complex. Using MM-401 and its enantiomer control MM-NC-401, we show that inhibiting MLL1 methyltransferase activity specifically blocks proliferation of MLL cells by inducing cell-cycle arrest, apoptosis, and myeloid differentiation without general toxicity to normal bone marrow cells or non-MLL cells. More importantly, transcriptome analyses show that MM-401 induces changes in gene expression similar to those of MLL1 deletion, supporting a predominant role of MLL1 activity in regulating MLL1-dependent leukemia transcription program. We envision broad applications for MM-401 in basic and translational research.