Inhibition of excessive autophagy and mitophagy mediates neuroprotective effects of URB597 against chronic cerebral hypoperfusion

Cell Death Dis. 2018 Jun 28;9(7):733. doi: 10.1038/s41419-018-0755-y.

Abstract

URB597 (URB) has therapeutic potential for treating chronic cerebral hypoperfusion (CCH)-induced neuronal death. The present study investigated the protective effects of URB on autopahgy and mitophagy in a CCH model as well as the underlying mechanisms. The ultrastructural changes were examined by electron microscopy. The mitochondrial membrane potential was assessed by immunofluorescence. The expressions of autophagy-related proteins (beclin-1, p62, and LC3), lysosome-related proteins (CTSD and LAMP1), and mitophagy-related proteins (BNIP3, cyt C and parkin) were evaluated by western blotting, and the interaction of beclin-1 and Bcl-2 were determined by immunoprecipitation. CCH significantly decreased the protein expression of p62, CTSD, and LAMP1 and increased the protein expression of beclin-1, parkin, and BNIP3, the LC3-II to LC3-I ratio, and the release of cyt C from mitochondria to cytoplasm. Furthermore, CCH induced the accumulation of ubiquitinated proteins in PSDs. However, URB significantly reversed these results. Besides, URB significantly inhibited the beclin-1 from beclin-1/Bcl-2 complex to whole-cell lysates. The above results indicate that URB could inhibit impaired autophagy degradation and the disruption of beclin-1/Bcl-2 complex and subsequently cut off BNIP3-cyt C- and parkin-required mitophagy, finally preventing the abnormal excessive autophagy and mitophagy. These findings provide new insights that URB is a promising agent for therapeutic management of CCH.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenylate Kinase / metabolism
  • Animals
  • Autophagosomes / drug effects
  • Autophagosomes / metabolism
  • Autophagosomes / ultrastructure
  • Autophagy / drug effects*
  • Beclin-1 / metabolism
  • Benzamides / pharmacology*
  • Brain Ischemia / pathology*
  • Carbamates / pharmacology*
  • Hippocampus / pathology
  • Lysosomes / drug effects
  • Lysosomes / metabolism
  • Male
  • Membrane Fusion / drug effects
  • Mitochondria / drug effects
  • Mitochondria / metabolism
  • Mitochondria / ultrastructure
  • Mitophagy / drug effects*
  • Neurons / drug effects
  • Neurons / metabolism
  • Neurons / ultrastructure
  • Neuroprotective Agents / pharmacology*
  • Phosphorylation / drug effects
  • Proto-Oncogene Proteins c-akt / metabolism
  • Proto-Oncogene Proteins c-bcl-2 / metabolism
  • Rats, Sprague-Dawley
  • Synapses / drug effects
  • Synapses / pathology
  • Synapses / ultrastructure
  • TOR Serine-Threonine Kinases / metabolism

Substances

  • Beclin-1
  • Benzamides
  • Carbamates
  • Neuroprotective Agents
  • Proto-Oncogene Proteins c-bcl-2
  • cyclohexyl carbamic acid 3'-carbamoylbiphenyl-3-yl ester
  • Proto-Oncogene Proteins c-akt
  • TOR Serine-Threonine Kinases
  • Adenylate Kinase