Autophagy defects contribute to neurodegeneration induced by dysfunctional ESCRT-III

Autophagy. 2009 Oct;5(7):1070-2. doi: 10.4161/auto.5.7.9823. Epub 2009 Oct 15.

Abstract

The endosomal sorting complex required for transport (ESCRT) machinery is involved in multiple cellular processes, including autophagy (macroautophagy). Autophagy is an important intracellular pathway that involves the formation and maturation of autophagosomes and their fusion with lysosomes for bulk degradation of cytoplasmic contents and organelles. In flies and cultured mammalian cells, autophagosomes accumulate when ESCRT-III is rendered dysfunctional by reduced activity of its subunits or by ectopic expression of mutant CHMP2B associated with frontotemporal dementia linked to chromosome 3 (FTD3). Compromised ESCRT-III function results in eventual neuronal cell loss; however, the mechanism of this form of neurodegeneration is largely unknown. Recently, we found that inhibiting autophagy induction in cultured cortical neurons, either by small-molecule inhibitors of phosphatidylinositol 3-kinases (PtdIns3K) or by loss of atg5 or atg7 activity, delays but does not completely suppress neuronal cell loss caused by dysfunctional ESCRT-III. These findings indicate that excess accumulation of autophagosomes is detrimental to neuronal survival, and dysfunctional ESCRT-III appears to cause neurodegeneration through multiple mechanisms.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Autophagy / physiology*
  • Endosomal Sorting Complexes Required for Transport / metabolism*
  • Humans
  • Nerve Degeneration / metabolism*
  • Nerve Tissue Proteins / metabolism
  • Neurons / metabolism
  • Phagosomes / metabolism
  • Protein Isoforms / metabolism

Substances

  • CHMP2B protein, human
  • Endosomal Sorting Complexes Required for Transport
  • Nerve Tissue Proteins
  • Protein Isoforms