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C9orf72 Proteins Regulate Autophagy and Undergo Autophagosomal or Proteasomal Degradation in a Cell Type-Dependent Manner

Dysfunctional autophagy or ubiquitin-proteasome system (UPS) are suggested to underlie abnormal protein aggregation in neurodegenerative diseases. Frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS)-associated C9orf72 is implicated in autophagy, but whether it activates or inhibits...

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Autores principales: Leskelä, Stina, Huber, Nadine, Rostalski, Hannah, Natunen, Teemu, Remes, Anne M., Takalo, Mari, Hiltunen, Mikko, Haapasalo, Annakaisa
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6829620/
https://www.ncbi.nlm.nih.gov/pubmed/31658762
http://dx.doi.org/10.3390/cells8101233
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author Leskelä, Stina
Huber, Nadine
Rostalski, Hannah
Natunen, Teemu
Remes, Anne M.
Takalo, Mari
Hiltunen, Mikko
Haapasalo, Annakaisa
author_facet Leskelä, Stina
Huber, Nadine
Rostalski, Hannah
Natunen, Teemu
Remes, Anne M.
Takalo, Mari
Hiltunen, Mikko
Haapasalo, Annakaisa
author_sort Leskelä, Stina
collection PubMed
description Dysfunctional autophagy or ubiquitin-proteasome system (UPS) are suggested to underlie abnormal protein aggregation in neurodegenerative diseases. Frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS)-associated C9orf72 is implicated in autophagy, but whether it activates or inhibits autophagy is partially controversial. Here, we utilized knockdown or overexpression of C9orf72 in mouse N2a neuroblastoma cells or cultured neurons to elucidate the potential role of C9orf72 proteins in autophagy and UPS. Induction of autophagy in C9orf72 knockdown N2a cells led to decreased LC3BI to LC3BII conversion, p62 degradation, and formation of LC3-containing autophagosomes, suggesting compromised autophagy. Proteasomal activity was slightly decreased. No changes in autophagy nor proteasomal activity in C9orf72-overexpressing N2a cells were observed. However, in these cells, autophagy induction by serum starvation or rapamycin led to significantly decreased C9orf72 levels. The decreased levels of C9orf72 in serum-starved N2a cells were restored by the proteasomal inhibitor lactacystin, but not by the autophagy inhibitor bafilomycin A1 (BafA1) treatment. These data suggest that C9orf72 undergoes proteasomal degradation in N2a cells during autophagy. Lactacystin significantly elevated C9orf72 levels in N2a cells and neurons, further suggesting UPS-mediated regulation. In rapamycin and BafA1-treated neurons, C9orf72 levels were significantly increased. Altogether, these findings corroborate the previously suggested regulatory role for C9orf72 in autophagy and suggest cell type-dependent regulation of C9orf72 levels via UPS and/or autophagy.
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spelling pubmed-68296202019-11-18 C9orf72 Proteins Regulate Autophagy and Undergo Autophagosomal or Proteasomal Degradation in a Cell Type-Dependent Manner Leskelä, Stina Huber, Nadine Rostalski, Hannah Natunen, Teemu Remes, Anne M. Takalo, Mari Hiltunen, Mikko Haapasalo, Annakaisa Cells Article Dysfunctional autophagy or ubiquitin-proteasome system (UPS) are suggested to underlie abnormal protein aggregation in neurodegenerative diseases. Frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS)-associated C9orf72 is implicated in autophagy, but whether it activates or inhibits autophagy is partially controversial. Here, we utilized knockdown or overexpression of C9orf72 in mouse N2a neuroblastoma cells or cultured neurons to elucidate the potential role of C9orf72 proteins in autophagy and UPS. Induction of autophagy in C9orf72 knockdown N2a cells led to decreased LC3BI to LC3BII conversion, p62 degradation, and formation of LC3-containing autophagosomes, suggesting compromised autophagy. Proteasomal activity was slightly decreased. No changes in autophagy nor proteasomal activity in C9orf72-overexpressing N2a cells were observed. However, in these cells, autophagy induction by serum starvation or rapamycin led to significantly decreased C9orf72 levels. The decreased levels of C9orf72 in serum-starved N2a cells were restored by the proteasomal inhibitor lactacystin, but not by the autophagy inhibitor bafilomycin A1 (BafA1) treatment. These data suggest that C9orf72 undergoes proteasomal degradation in N2a cells during autophagy. Lactacystin significantly elevated C9orf72 levels in N2a cells and neurons, further suggesting UPS-mediated regulation. In rapamycin and BafA1-treated neurons, C9orf72 levels were significantly increased. Altogether, these findings corroborate the previously suggested regulatory role for C9orf72 in autophagy and suggest cell type-dependent regulation of C9orf72 levels via UPS and/or autophagy. MDPI 2019-10-10 /pmc/articles/PMC6829620/ /pubmed/31658762 http://dx.doi.org/10.3390/cells8101233 Text en © 2019 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Leskelä, Stina
Huber, Nadine
Rostalski, Hannah
Natunen, Teemu
Remes, Anne M.
Takalo, Mari
Hiltunen, Mikko
Haapasalo, Annakaisa
C9orf72 Proteins Regulate Autophagy and Undergo Autophagosomal or Proteasomal Degradation in a Cell Type-Dependent Manner
title C9orf72 Proteins Regulate Autophagy and Undergo Autophagosomal or Proteasomal Degradation in a Cell Type-Dependent Manner
title_full C9orf72 Proteins Regulate Autophagy and Undergo Autophagosomal or Proteasomal Degradation in a Cell Type-Dependent Manner
title_fullStr C9orf72 Proteins Regulate Autophagy and Undergo Autophagosomal or Proteasomal Degradation in a Cell Type-Dependent Manner
title_full_unstemmed C9orf72 Proteins Regulate Autophagy and Undergo Autophagosomal or Proteasomal Degradation in a Cell Type-Dependent Manner
title_short C9orf72 Proteins Regulate Autophagy and Undergo Autophagosomal or Proteasomal Degradation in a Cell Type-Dependent Manner
title_sort c9orf72 proteins regulate autophagy and undergo autophagosomal or proteasomal degradation in a cell type-dependent manner
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6829620/
https://www.ncbi.nlm.nih.gov/pubmed/31658762
http://dx.doi.org/10.3390/cells8101233
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