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Published on: May 12, 2013
Antisense oligonucleotides directed against App and Rab5 normalized endosomal Rab activity and reversed DS-AD-linked
Xu-Qiao Chen1, Xinxin Zuo1, Ann Becker1
1Department of Neurosciences, University of California San Diego, La Jolla, California, USA.
Introduction:
Down syndrome (DS) markedly raises the risk of Alzheimer's disease (DS-AD). Our findings identified widespread dysregulation of the endolysosomal network (ELN) in DS and DS-AD brains, driven by increased APP gene dose, hyperactivation of RAB5, and elevated levels of guanine nucleotide exchange factors (GEFs) for RABs 7 and 11.
Methods:
We investigated whether increasing APP gene dose and RAB5 hyperactivation contributed to neuropathogenesis and whether a clinically feasible intervention could reverse ELN changes. The Dp16 DS-AD mouse model was treated with a mouse App-specific antisense oligonucleotide (App-ASO) and Rab5-specific ASOs targeting Rab5a and Rab5b.
Results:
App-ASO treatment normalized full-length APP (fl-APP) and its products, RAB5 activity, and downstream RABs 7 and 11 pathways. Rab5-ASOs reduced RAB5 levels and restored endosomal Rab activity. Both ASO treatments mitigated DS-AD-linked pathologies.
Discussion:
These findings highlight ELN dysregulation in DS and the therapeutic potential of ASO-based strategies targeting APP or Rab5 to counteract DS-AD features.
Highlights:
App-ASO treatment reduced the levels of APP and its products and normalized endosomal Rab activity and GEF levels in Dp16 mice. Administration of Rab5-ASOs reduced RAB5 levels and normalized endosomal Rab activity and GEF levels in Dp16 mice. Both ASO treatments were well tolerated and mitigated APP-linked pathologies including tau hyperphosphorylation, neurotrophin signaling deficits, and synaptic protein loss. App-ASO or Rab5-ASOs reversed established pathological phenotypes in Dp16 mice.
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