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Pathogenic variants of Valosin‐containing protein induce lysosomal damage and transcriptional activation of autophagy regulators in neuronal cells
Author(s) -
Ferrari Veronica,
Cristofani Riccardo,
Cicardi Maria E.,
Tedesco Barbara,
Crippa Valeria,
Chierichetti Marta,
Casarotto Elena,
Cozzi Marta,
Mina Francesco,
Galbiati Mariarita,
Piccolella Margherita,
Carra Serena,
Vaccari Thomas,
Nalbandian Angele,
Kimonis Virginia,
Fortuna Tyler R.,
Pandey Udai B.,
Gagliani Maria C.,
Cortese Katia,
Rusmini Paola,
Poletti Angelo
Publication year - 2022
Publication title -
neuropathology and applied neurobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.538
H-Index - 95
eISSN - 1365-2990
pISSN - 0305-1846
DOI - 10.1111/nan.12818
Subject(s) - autophagy , tfeb , microbiology and biotechnology , sequestosome 1 , lysosome , lamp1 , protein aggregation , mutant , biology , intracellular , atg16l1 , autophagosome , chemistry , biochemistry , apoptosis , gene , enzyme
Aim Mutations in the valosin‐containing protein ( VCP ) gene cause various lethal proteinopathies that mainly include inclusion body myopathy with Paget's disease of bone and frontotemporal dementia (IBMPFD) and amyotrophic lateral sclerosis (ALS). Different pathological mechanisms have been proposed. Here, we define the impact of VCP mutants on lysosomes and how cellular homeostasis is restored by inducing autophagy in the presence of lysosomal damage. Methods By electron microscopy, we studied lysosomal morphology in VCP animal and motoneuronal models. With the use of western blotting, real‐time quantitative polymerase chain reaction (RT‐qPCR), immunofluorescence and filter trap assay, we evaluated the effect of selected VCP mutants in neuronal cells on lysosome size and activity, lysosomal membrane permeabilization and their impact on autophagy. Results We found that VCP mutants induce the formation of aberrant multilamellar organelles in VCP animal and cell models similar to those found in patients with VCP mutations or with lysosomal storage disorders. In neuronal cells, we found altered lysosomal activity characterised by membrane permeabilization with galectin‐3 redistribution and activation of PPP3CB. This selectively activated the autophagy/lysosomal transcriptional regulator TFE3, but not TFEB, and enhanced both SQSTM1/p62 and lipidated MAP1LC3B levels inducing autophagy. Moreover, we found that wild type VCP, but not the mutants, counteracted lysosomal damage induced either by trehalose or by a mutant form of SOD1 (G93A), also blocking the formation of its insoluble intracellular aggregates. Thus, chronic activation of autophagy might fuel the formation of multilamellar bodies. Conclusion Together, our findings provide insights into the pathogenesis of VCP‐related diseases, by proposing a novel mechanism of multilamellar body formation induced by VCP mutants that involves lysosomal damage and induction of lysophagy.