Browsing by Subject "stem cells"

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Open Access
A long non-coding RNA targets microRNA miR-34a to regulate colon cancer stem cell asymmetric division.
(Elife, 2016-04-14) Wang, Lihua; Bu, Pengcheng; Ai, Yiwei; Srinivasan, Tara; Chen, Huanhuan Joyce; Xiang, Kun; Lipkin, Steven M; Shen, Xiling
The roles of long non-coding RNAs (lncRNAs) in regulating cancer and stem cells are being increasingly appreciated. Its diverse mechanisms provide the regulatory network with a bigger repertoire to increase complexity. Here we report a novel LncRNA, Lnc34a, that is enriched in colon cancer stem cells (CCSCs) and initiates asymmetric division by directly targeting the microRNA miR-34a to cause its spatial imbalance. Lnc34a recruits Dnmt3a via PHB2 and HDAC1 to methylate and deacetylate the miR-34a promoter simultaneously, hence epigenetically silencing miR-34a expression independent of its upstream regulator, p53. Lnc34a levels affect CCSC self-renewal and colorectal cancer (CRC) growth in xenograft models. Lnc34a is upregulated in late-stage CRCs, contributing to epigenetic miR-34a silencing and CRC proliferation. The fact that lncRNA targets microRNA highlights the regulatory complexity of non-coding RNAs (ncRNAs), which occupy the bulk of the genome.
Open Access
Bispecific Antibody Therapy for Effective Cardiac Repair through Redirection of Endogenous Stem Cells
(Advanced Therapeutics, 2019-10-01) Huang, K; Li, Z; Su, T; Shen, D; Hu, S; Cheng, K
Bone marrow stem cells (BMSCs) are a promising strategy for cardiac regenerative therapy for myocardial infarction (MI). However, cell transplantation has to overcome a number of hurdles, such as cell quality control, clinical practicality, low cell retention/engraftment, and immune reactions when allogeneic cells are used. Bispecific antibodies (BsAbs) have been developed as potential agents in cancer immunotherapy but their application is sparse in cardiovascular diseases. In the present study, BsAbs are designed by chemical cycloaddition of F(ab′)2 fragments from monoclonal anti-CD34 and anti- cardiac myosin heavy chain (CMHC) antibodies, which specifically targets circulating CD34-positive cells and injured cardiomyocytes simultaneously. It is hypothesized that intravenous administration of stem cell re-directing (SCRD) BsAbs (anti-CD34-F(ab′)2–anti-CMHC-F(ab′)2) can home endogenous BMSCs to the injured heart for cardiac repair. The in vivo studies in a mouse model with heart ischemia/reperfusion (I/R) injury demonstrate the safety and therapeutic potency of SCRD BsAb, which supports cardiac recovery by reducing scarring, promoting angiomyogenesis, and boosting cardiac function.
Open Access
Nrg1 is an injury-induced cardiomyocyte mitogen for the endogenous heart regeneration program in zebrafish.
(Elife, 2015-04-01) Gemberling, Matthew; Karra, Ravi; Dickson, Amy L; Poss, Kenneth D
Heart regeneration is limited in adult mammals but occurs naturally in adult zebrafish through the activation of cardiomyocyte division. Several components of the cardiac injury microenvironment have been identified, yet no factor on its own is known to stimulate overt myocardial hyperplasia in a mature, uninjured animal. In this study, we find evidence that Neuregulin1 (Nrg1), previously shown to have mitogenic effects on mammalian cardiomyocytes, is sharply induced in perivascular cells after injury to the adult zebrafish heart. Inhibition of Erbb2, an Nrg1 co-receptor, disrupts cardiomyocyte proliferation in response to injury, whereas myocardial Nrg1 overexpression enhances this proliferation. In uninjured zebrafish, the reactivation of Nrg1 expression induces cardiomyocyte dedifferentiation, overt muscle hyperplasia, epicardial activation, increased vascularization, and causes cardiomegaly through persistent addition of wall myocardium. Our findings identify Nrg1 as a potent, induced mitogen for the endogenous adult heart regeneration program.