A block of autophagy in lysosomal storage disorders

Carmine Settembre, Alessandro Fraldi, Luca Jahreiss, Carmine Spampanato, Consuelo Venturi, Diego Medina, Raquel de Pablo, Carlo Tacchetti, David C. Rubinsztein, Andrea Ballabio

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Abstract

Most lysosomal storage disorders (LSDs) are caused by deficiencies of lysosomal hydrolases. While LSDs were among the first inherited diseases for which the underlying biochemical defects were identified, the mechanisms from enzyme deficiency to cell death are poorly understood. Here we show that lysosomal storage impairs autophagic delivery of bulk cytosolic contents to lysosomes. By studying the mouse models of two LSDs associated with severe neurodegeneration, multiple sulfatase deficiency (MSD) and mucopolysaccharidosis type IIIA (MPSIIIA), we observed an accumulation of autophagosomes resulting from defective autophagosome-lysosome fusion. An impairment of the autophagic pathway was demonstrated by the inefficient degradation of exogenous aggregate-prone proteins (i.e. expanded huntingtin and mutated alpha-synuclein) in cells from LSD mice. This impairment resulted in massive accumulation of polyubiquitinated proteins and of dysfunctional mitochondria which are the putative mediators of cell death. These data identify LSDs as 'autophagy disorders' and suggest the presence of common mechanisms in the pathogenesis of these and other neurodegenerative diseases.

Original languageEnglish
Pages (from-to)119-129
Number of pages11
JournalHuman Molecular Genetics
Volume17
Issue number1
DOIs
Publication statusPublished - Jan 1 2008

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ASJC Scopus subject areas

  • Genetics

Cite this

Settembre, C., Fraldi, A., Jahreiss, L., Spampanato, C., Venturi, C., Medina, D., de Pablo, R., Tacchetti, C., Rubinsztein, D. C., & Ballabio, A. (2008). A block of autophagy in lysosomal storage disorders. Human Molecular Genetics, 17(1), 119-129. https://doi.org/10.1093/hmg/ddm289