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Abner JJ, Franklin JL, Clement MA, Hinger SA, Allen RM, Liu X, Kellner S, Wu J, Karijolich J, Liu Q, Vickers KC, Dedon P, Weaver AM, Coffey RJ, Patton JG. Depletion of METTL3 alters cellular and extracellular levels of miRNAs containing m 6A consensus sequences. Heliyon 2021; 7:e08519. [PMID: 34934837 PMCID: PMC8654799 DOI: 10.1016/j.heliyon.2021.e08519] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 11/02/2021] [Accepted: 11/29/2021] [Indexed: 12/21/2022] Open
Abstract
Extracellular vesicles (EVs) are capable of transferring cargo from donor to recipient cells, but precisely how cargo content is regulated for export is mostly unknown. For miRNA cargo, we previously showed that when compared to isogenic colorectal cancer (CRC) cells expressing wild-type KRAS, a distinct subset of miRNAs are differentially enriched in EVs from KRAS mutant active CRC cells, with miR-100 being one of the most enriched. The mechanisms that could explain how miR-100 and other miRNAs are differentially exported into EVs have not been fully elucidated. Here, we tested the effect of N6-methyladenosine (m6A) modification on miRNA export into EVs by depletion of METTL3 and ALKBH5, a writer and eraser of m6A modification, respectively. While the effects of ALKBH5 knockdown were quite modest, decreased levels of METTL3 led to reduced cellular and extracellular levels of a subset of miRNAs that contain consensus sequences for m6A modification. Functional testing of EVs prepared from cells expressing shRNAs against METTL3 showed that they were less capable of conferring colony growth in 3D to wild-type KRAS cells and were also largely incapable of conferring the spread of cetuximab resistance. Our data support a role for METTL3 modification on cellular miRNA levels and export of specific miRNAs.
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Affiliation(s)
- Jessica J. Abner
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, 37235, USA
| | - Jeffrey L. Franklin
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, 37235, USA
- Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, TN, 37235, USA
| | - Margaret A. Clement
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, 37235, USA
| | - Scott A. Hinger
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, 37235, USA
| | - Ryan M. Allen
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, 37235, USA
| | - Xiao Liu
- Department of Biostatistics, Vanderbilt University Medical Center, Nashville, TN, 37235, USA
| | - Stefanie Kellner
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Junzhou Wu
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - John Karijolich
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN, 37235, USA
| | - Qi Liu
- Department of Biostatistics, Vanderbilt University Medical Center, Nashville, TN, 37235, USA
| | - Kasey C. Vickers
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, 37235, USA
| | - Peter Dedon
- Singapore-MIT Alliance for Research and Technology, Singapore
| | - Alissa M. Weaver
- Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, TN, 37235, USA
| | - Robert J. Coffey
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, 37235, USA
- Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, TN, 37235, USA
| | - James G. Patton
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, 37235, USA
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Didiano D, Abner JJ, Hinger SA, Flickinger Z, Kent M, Clement MA, Balaiya S, Liu Q, Dai X, Levine EM, Patton JG. Induction of a proliferative response in the zebrafish retina by injection of extracellular vesicles. Exp Eye Res 2020; 200:108254. [PMID: 32961174 DOI: 10.1016/j.exer.2020.108254] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 08/26/2020] [Accepted: 09/14/2020] [Indexed: 12/18/2022]
Abstract
Ongoing research using cell transplantation and viral-mediated gene therapy has been making progress to restore vision by retinal repair, but targeted delivery and complete cellular integration remain challenging. An alternative approach is to induce endogenous Müller glia (MG) to regenerate lost neurons and photoreceptors, as occurs spontaneously in teleost fish and amphibians. Extracellular vesicles (EVs) can transfer protein and RNA cargo between cells serving as a novel means of cell-cell communication. We conducted an in vivo screen in zebrafish to identify sources of EVs that could induce MG to dedifferentiate and generate proliferating progenitor cells after intravitreal injection into otherwise undamaged zebrafish eyes. Small EVs (sEVs) from C6 glioma cells were the most consistent at inducing MG-derived proliferating cells. Ascl1a expression increased after intravitreal injection of C6 sEVs and knockdown of ascl1a inhibited the induction of proliferation. Proteomic and RNAseq analyses of EV cargo content were performed to begin to identify key factors that might target EVs to MG and initiate retina regeneration.
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Affiliation(s)
- Dominic Didiano
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, 37235, USA
| | - Jessica J Abner
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, 37235, USA
| | - Scott A Hinger
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, 37235, USA
| | - Zachary Flickinger
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, 37235, USA
| | - Matthew Kent
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, 37235, USA
| | - Margaret A Clement
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, 37235, USA
| | - Sankarathi Balaiya
- Department of Ophthalmology, Vanderbilt University Medical Center, Nashville, TN, 37235, USA
| | - Qi Liu
- Department of Biostatistics, Vanderbilt University Medical Center, Nashville, TN, 37235, USA
| | - Xiaozhuan Dai
- Department of Biostatistics, Vanderbilt University Medical Center, Nashville, TN, 37235, USA
| | - Edward M Levine
- Department of Ophthalmology, Vanderbilt University Medical Center, Nashville, TN, 37235, USA
| | - James G Patton
- Department of Biological Sciences, Vanderbilt University, Nashville, TN, 37235, USA.
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Abstract
Homologous series of L-methionine alkyl ester hydrochlorides and tosylates were synthesized and evaluated for in vitro growth inhibitory activity in Meth A sarcoma. Cytotoxicity, as determined by [3H]thymidine incorporation, was found to be directly proportional to alkyl chain length and surface tension lowering activity. L-Methionine decyl and dodecyl ester hydrochlorides possessed optimum cytotoxic activity (IC50 = 29, 28 microM) which was not reversible by the addition of L-methionine. Surface tension of a 50 microM solution of the decyl and dodecyl ester hydrochlorides were 35.4 and 32.7 dyn/cm, respectively. The corresponding decyl and dodecyl ester tosylates and amide hydrochlorides were less active. The N-t-butoxycarbonyl analogues were essentially inactive, demonstrating the necessity of an unsubstituted and/or potentially cationic amino group. Methionine dependence characteristics and cytotoxicity were also determined for three human (IMR-90, LX-1, MCF7) and four additional murine (L1210, L5178Y, 3T3, SV-T2) cell lines. The human cell lines Meth A, LX-1, and SV-T2 were found to be methionine independent. The LX-1 tumor cell line and the SV-T2 transformed line exhibited two to four times more sensitivity to the cytotoxic and cytolytic properties of the decyl and dodecyl ester hydrochlorides than their normal counterparts. The dodecyl amide hydrochloride derivative demonstrated enhanced cytotoxic activity in vivo relative to the corresponding ester, possibly due to decreased metabolic hydrolysis.
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Affiliation(s)
- M A Clement
- Department of Basic Pharmaceutical Sciences, College of Pharmacy, University of South Carolina, Columbia 29208
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