Macrocyclic Immunoproteasome Inhibitors as a Potential Therapy for Alzheimer's Disease

J Med Chem. 2021 Aug 12;64(15):10934-10950. doi: 10.1021/acs.jmedchem.1c00291. Epub 2021 Jul 26.

Abstract

Previously, we reported that immunoproteasome (iP)-targeting linear peptide epoxyketones improve cognitive function in mouse models of Alzheimer's disease (AD) in a manner independent of amyloid β. However, these compounds' clinical prospect for AD is limited due to potential issues, such as poor brain penetration and metabolic instability. Here, we report the development of iP-selective macrocyclic peptide epoxyketones prepared by a ring-closing metathesis reaction between two terminal alkenes attached at the P2 and P3/P4 positions of linear counterparts. We show that a lead macrocyclic compound DB-60 (20) effectively inhibits the catalytic activity of iP in ABCB1-overexpressing cells (IC50: 105 nM) and has metabolic stability superior to its linear counterpart. DB-60 (20) also lowered the serum levels of IL-1α and ameliorated cognitive deficits in Tg2576 mice. The results collectively suggest that macrocyclic peptide epoxyketones have improved CNS drug properties than their linear counterparts and offer promising potential as an AD drug candidate.

Publication types

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

MeSH terms

  • Alzheimer Disease / drug therapy*
  • Alzheimer Disease / metabolism
  • Animals
  • Cells, Cultured
  • Dose-Response Relationship, Drug
  • Humans
  • Macrocyclic Compounds / chemical synthesis
  • Macrocyclic Compounds / chemistry
  • Macrocyclic Compounds / pharmacology*
  • Mice
  • Mice, Inbred C57BL
  • Mice, Transgenic
  • Molecular Structure
  • Proteasome Endopeptidase Complex / metabolism*
  • Proteasome Inhibitors / chemical synthesis
  • Proteasome Inhibitors / chemistry
  • Proteasome Inhibitors / pharmacology*
  • Structure-Activity Relationship

Substances

  • Macrocyclic Compounds
  • Proteasome Inhibitors
  • Proteasome Endopeptidase Complex