hes1-protein--human and Leukemia

Mesenchymal stem cell (MSC)-based therapy has emerged as a promising treatment for spinal cord injury (SCI), but improving the neurogenic potential of MSCs remains a challenge. Mixed lineage leukemia 1 (MLL1), an H3K4me3 methyltransferases, plays a critical role in regulating lineage-specific gene expression and influences neurogenesis. In this study, we investigated the role and mechanism of MLL1 in the neurogenesis of stem cells from apical papilla (SCAPs). We examined the expression of neural markers, and the nerve repair and regeneration ability of SCAPs using dynamic changes in neuron-like cells, immunofluorescence staining, and a SCI model. We employed a coimmunoprecipitation (Co-IP) assay, real-time RT-PCR, microarray analysis, and chromatin immunoprecipitation (ChIP) assay to investigate the molecular mechanism. The results showed that MLL1 knock-down increased the expression of neural markers, including neurogenic differentiation factor (NeuroD), neural cell adhesion molecule (NCAM), tyrosine hydroxylase (TH), βIII-tubulin and Nestin, and promoted neuron-like cell formation in SCAPs. In vivo, a transplantation experiment showed that depletion of MLL 1 in SCAPs can restore motor function in a rat SCI model. MLL1 can combine with WD repeat domain 5 (WDR5) and WDR5 inhibit the expression of neural markers in SCAPs. MLL1 regulates Hairy and enhancer of split 1 (HES1) expression by directly binds to HES1 promoters via regulating H3K4me3 methylation by interacting with WDR5. Additionally, HES1 enhances the expression of neural markers in SCAPs. Our findings demonstrate that MLL1 inhibits the neurogenic potential of SCAPs by interacting with WDR5 and repressing HES1. These results provide a potential therapeutic target for promoting the recovery of motor function in SCI patients.

Topics: Animals; Cell Differentiation; Humans; Intracellular Signaling Peptides and Proteins; Leukemia; Mesenchymal Stem Cells; Neurogenesis; Rats; Stem Cells; Transcription Factor HES-1

Human CAP10-like protein 46 kDa (hCLP46) is the homolog of Rumi, which is the first identified protein O-glucosyltransferase that modifies Notch receptor in Drosophila. Dysregulation of hCLP46 occurs in many hematologic diseases, but the role of hCLP46 remains unclear. Knockdown of hCLP46 by RNA interference resulted in decreased protein levels of endogenous Notch1, Notch intracellular domain (NICD) and Notch target gene Hes-1, suggesting the impairment of the Notch signaling. However, neither cell surface Notch expression nor ligand binding activities were affected. In addition, down-regulated expression of hCLP46 inhibited the proliferation of U937 cells, which was correlated with increased cyclin-dependent kinase inhibitor (CDKI) CDKN1B (p27) and decreased phosphorylation of retinoblastoma (RB) protein. We showed that lack of hCLP46 results in impaired ligand induced Notch activation in mammalian cell, and hCLP46 regulates the proliferation of U937 cell through CDKI-RB signaling pathway, which may be important for the pathogenesis of leukemia.

Topics: Basic Helix-Loop-Helix Transcription Factors; CDC2 Protein Kinase; Cell Proliferation; Cyclin-Dependent Kinase Inhibitor p27; Gene Knockdown Techniques; Glucosyltransferases; Homeodomain Proteins; Humans; Jurkat Cells; Leukemia; Proteins; Receptor, Notch1; Receptors, Notch; Retinoblastoma Protein; RNA Interference; Signal Transduction; Transcription Factor HES-1; U937 Cells

Notch activation is involved in the growth of leukemia cells. gamma-Secretase inhibitors (GSIs), which block Notch activation, may be candidates for molecular target therapy against leukemia.. The effects of three kinds of GSIs: GSI-IX, GSI-XII and GSI-XXI, on the in vitro growth of various leukemia cell lines were examined.. The effects of GSI were diverse depending upon the combination of cells and GSI. GSI treatment suppressed the growth of most of the cell lines examined. Conversely, the growth of some cell lines were promoted by GSI-XXI. GSI-XXI treatment reduced the amount of cleaved Notch1 protein and HES1 mRNA in the cells, which means that it suppressed Notch activity. The treatment up-regulated mRNA of nuclear factor kappa-B1 (NFKB1) and v-rel reticuloendotheliosis viral oncogene homolog A (RELA), which can be a cause of growth promotion.. The diverse effects of GSIs must be elucidated before clinical use because they can stimulate the growth of leukemia cells.

Topics: Amyloid Precursor Protein Secretases; Apoptosis; Basic Helix-Loop-Helix Transcription Factors; Cell Line, Tumor; Cell Proliferation; Dipeptides; Homeodomain Proteins; Humans; Immunoblotting; Leukemia; NF-kappa B; Receptor, Notch1; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Transcription Factor HES-1; Transcription Factor RelA