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EMBO J. 2016 Jan 18;35(2):121-42. doi: 10.15252/embj.201591998. Epub 2015 Dec 23.

TDP-43 loss of function increases TFEB activity and blocks autophagosome-lysosome fusion.

Author information

1
Laboratory of Molecular Neuropathology, Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases and College of Pharmaceutical Sciences, Soochow University, Suzhou, Jiangsu, China.
2
Key Laboratory of Brain Function and Disease, School of Life Sciences University of Science & Technology of China Chinese Academy of Sciences, Hefei, Anhui, China.
3
Key Laboratory of Developmental Genes and Human Disease, Institute of Life Sciences Southeast University, Nanjing, Jiangsu, China.
4
Laboratory of Molecular Neuropathology, Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases and College of Pharmaceutical Sciences, Soochow University, Suzhou, Jiangsu, China Jiangsu Key Laboratory of Preventive and Translational Medicine for Geriatric Diseases, College of Pharmaceutical Sciences Soochow University, Suzhou, Jiangsu, China wanggh@suda.edu.cn zheng.ying@suda.edu.cn.
5
Laboratory of Molecular Neuropathology, Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases and College of Pharmaceutical Sciences, Soochow University, Suzhou, Jiangsu, China Key Laboratory of Brain Function and Disease, School of Life Sciences University of Science & Technology of China Chinese Academy of Sciences, Hefei, Anhui, China wanggh@suda.edu.cn zheng.ying@suda.edu.cn.

Abstract

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease that is characterized by selective loss of motor neurons in brain and spinal cord. TAR DNA-binding protein 43 (TDP-43) was identified as a major component of disease pathogenesis in ALS, frontotemporal lobar degeneration (FTLD), and other neurodegenerative disease. Despite the fact that TDP-43 is a multi-functional protein involved in RNA processing and a large number of TDP-43 RNA targets have been discovered, the initial toxic effect and the pathogenic mechanism underlying TDP-43-linked neurodegeneration remain elusive. In this study, we found that loss of TDP-43 strongly induced a nuclear translocation of TFEB, the master regulator of lysosomal biogenesis and autophagy, through targeting the mTORC1 key component raptor. This regulation in turn enhanced global gene expressions in the autophagy-lysosome pathway (ALP) and increased autophagosomal and lysosomal biogenesis. However, loss of TDP-43 also impaired the fusion of autophagosomes with lysosomes through dynactin 1 downregulation, leading to accumulation of immature autophagic vesicles and overwhelmed ALP function. Importantly, inhibition of mTORC1 signaling by rapamycin treatment aggravated the neurodegenerative phenotype in a TDP-43-depleted Drosophila model, whereas activation of mTORC1 signaling by PA treatment ameliorated the neurodegenerative phenotype. Taken together, our data indicate that impaired mTORC1 signaling and influenced ALP may contribute to TDP-43-mediated neurodegeneration.

KEYWORDS:

ALS; Autophagy; TDP‐43; TFEB; mTORC1

PMID:
26702100
PMCID:
PMC4718457
DOI:
10.15252/embj.201591998
[Indexed for MEDLINE]
Free PMC Article

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