University of Oulu

Rostalski H, Hietanen T, Leskelä S, Behánová A, Abdollahzadeh A, Wittrahm R, Mäkinen P, Huber N, Hoffmann D, Solje E, Remes AM, Natunen T, Takalo M, Tohka J, Hiltunen M and Haapasalo A (2020) BV-2 Microglial Cells Overexpressing C9orf72 Hexanucleotide Repeat Expansion Produce DPR Proteins and Show Normal Functionality but No RNA Foci. Front. Neurol. 11:550140. doi: 10.3389/fneur.2020.550140

BV-2 microglial cells overexpressing C9orf72 hexanucleotide repeat expansion produce DPR proteins and show normal functionality but no RNA foci

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Author: Rostalski, Hannah1; Hietanen, Tomi1; Leskelä, Stina1;
Organizations: 1A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland
2Institute of Biomedicine, University of Eastern Finland, Kuopio, Finland
3Institute of Clinical Medicine—Neurology, University of Eastern Finland, Kuopio, Finland
4Neuro Center, Neurology, Kuopio University Hospital, Kuopio, Finland
5Unit of Clinical Neuroscience, Neurology, University of Oulu, Oulu, Finland
6Medical Research Center (MRC) Oulu, Oulu University Hospital, Oulu, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 3.4 MB)
Persistent link: http://urn.fi/urn:nbn:fi-fe202102124686
Language: English
Published: Frontiers Media, 2020
Publish Date: 2021-02-12
Description:

Abstract

Hexanucleotide repeat expansion (HRE) in the chromosome 9 open-reading frame 72 (C9orf72) gene is the most common genetic cause underpinning frontotemporal lobar degeneration (FTLD) and amyotrophic lateral sclerosis (ALS). It leads to the accumulation of toxic RNA foci and various dipeptide repeat (DPR) proteins into cells. These C9orf72 HRE-specific hallmarks are abundant in neurons. So far, the role of microglia, the immune cells of the brain, in C9orf72 HRE-associated FTLD/ALS is unclear. In this study, we overexpressed C9orf72 HRE of a pathological length in the BV-2 microglial cell line and used biochemical methods and fluorescence imaging to investigate its effects on their phenotype, viability, and functionality. We found that BV-2 cells expressing the C9orf72 HRE presented strong expression of specific DPR proteins but no sense RNA foci. Transiently increased levels of cytoplasmic TAR DNA-binding protein 43 (TDP-43), slightly altered levels of p62 and lysosome-associated membrane protein (LAMP) 2A, and reduced levels of polyubiquitinylated proteins, but no signs of cell death were detected in HRE overexpressing cells. Overexpression of the C9orf72 HRE did not affect BV-2 cell phagocytic activity or response to an inflammatory stimulus, nor did it shift their RNA profile toward disease-associated microglia. These findings suggest that DPR proteins do not affect microglial cell viability or functionality in BV-2 cells. However, additional studies in other models are required to further elucidate the role of C9orf72 HRE in microglia.

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Series: Frontiers in neurology
ISSN: 1664-2295
ISSN-E: 1664-2295
ISSN-L: 1664-2295
Volume: 11
Article number: 550140
DOI: 10.3389/fneur.2020.550140
OADOI: https://oadoi.org/10.3389/fneur.2020.550140
Type of Publication: A1 Journal article – refereed
Field of Science: 3112 Neurosciences
Subjects:
Funding: This study was supported by grants from the Academy of Finland, Grant Nos. 315459 (AH), 315460 (AR), 288659 (TN), 316258 (JT), and 307866 (MH); Yrjö Jahnsson Foundation, Grant No. 20187070 (AH); ALS tutkimuksen tuki ry. registered association (HR, SL, and NH); Sigrid Jusélius Foundation (MH); the Strategic Neuroscience Funding of the University of Eastern Finland (AH and MH); and Neurocenter Finland—AlzTrans pilot project (MH).
Academy of Finland Grant Number: 315460
Detailed Information: 315460 (Academy of Finland Funding decision)
Copyright information: © 2020 Rostalski, Hietanen, Leskelä, Behánová, Abdollahzadeh, Wittrahm, Mäkinen, Huber, Hoffmann, Solje, Remes, Natunen, Takalo, Tohka, Hiltunen and Haapasalo. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
  https://creativecommons.org/licenses/by/4.0/