Transcriptional induction of the heat shock protein B8 mediates the clearance of misfolded proteins responsible for motor neuron diseases

Sci Rep. 2016 Mar 10;6:22827. doi: 10.1038/srep22827.

Abstract

Neurodegenerative diseases (NDs) are often associated with the presence of misfolded protein inclusions. The chaperone HSPB8 is upregulated in mice, the human brain and muscle structures affected during NDs progression. HSPB8 exerts a potent pro-degradative activity on several misfolded proteins responsible for familial NDs forms. Here, we demonstrated that HSPB8 also counteracts accumulation of aberrantly localized misfolded forms of TDP-43 and its 25 KDa fragment involved in most sporadic cases of Amyotrophic Lateral Sclerosis (sALS) and of Fronto Lateral Temporal Dementia (FLTD). HSPB8 acts with BAG3 and the HSP70/HSC70-CHIP complex enhancing the autophagic removal of misfolded proteins. We performed a high-through put screening (HTS) to find small molecules capable of inducing HSPB8 in neurons for therapeutic purposes. We identified two compounds, colchicine and doxorubicin, that robustly up-regulated HSPB8 expression. Both colchicine and doxorubicin increased the expression of the master regulator of autophagy TFEB, the autophagy linker p62/SQSTM1 and the autophagosome component LC3. In line, both drugs counteracted the accumulation of TDP-43 and TDP-25 misfolded species responsible for motoneuronal death in sALS. Thus, analogs of colchicine and doxorubicin able to induce HSPB8 and with better safety and tolerability may result beneficial in NDs models.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amyotrophic Lateral Sclerosis / metabolism
  • Animals
  • Autophagy
  • Cell Line
  • Colchicine / pharmacology*
  • DNA-Binding Proteins / biosynthesis
  • Doxorubicin / pharmacology*
  • Frontotemporal Dementia / metabolism
  • Heat-Shock Proteins / biosynthesis*
  • Heat-Shock Response / drug effects
  • High-Throughput Screening Assays
  • Humans
  • Mice
  • Molecular Chaperones
  • Motor Neurons / cytology
  • Motor Neurons / drug effects*
  • Motor Neurons / metabolism
  • Peptide Fragments / biosynthesis
  • Protein Folding
  • Protein Serine-Threonine Kinases / biosynthesis*
  • Transcription, Genetic

Substances

  • DNA-Binding Proteins
  • HSPB8 protein, human
  • Heat-Shock Proteins
  • Molecular Chaperones
  • Peptide Fragments
  • TARDBP protein, human
  • TDP-25 protein, human
  • Doxorubicin
  • Protein Serine-Threonine Kinases
  • Colchicine