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MiR-298 Counteracts Mutant Androgen Receptor Toxicity in Spinal and Bulbar Muscular Atrophy

Thursday, September 15, 2016 — Poster Session III

3:30 p.m. – 5:00 p.m.
FAES Terrace
NINDS
NEURO-23

Authors

  • N Pourshafie
  • P Lee
  • K Chen
  • G Harmison
  • L Bott
  • M Katsuno
  • G Sobue
  • B Burnett
  • K Fischbeck
  • C Rinaldi

Abstract

Spinal and bulbar muscular atrophy (SBMA) is a currently untreatable adult-onset neuromuscular disease caused by expansion of a polyglutamine repeat in the androgen receptor (AR). In SBMA, as in other polyglutamine diseases, a toxic gain of function in the mutant protein is an important factor in the disease mechanism; therefore, reducing the mutant protein holds promise as an effective treatment strategy. In this work we evaluated a microRNA (miRNA) to reduce AR expression. From a list of predicted miRNAs that target human AR, we selected microRNA-298 (miR-298) for its ability to down-regulate AR mRNA and protein levels when transfected in cells overexpressing wild-type and mutant AR and in SBMA patient-derived fibroblasts. We showed that miR-298 directly binds to the 3'-untranslated region (UTR) of the human AR transcript, and counteracts AR toxicity in vitro. Intravenous delivery of miR- 298 with adeno-associated virus serotype 9 vector resulted in efficient transduction of muscle and spinal cord and amelioration of the disease phenotype in SBMA mice. Our findings support the development of miRNAs as a therapeutic strategy for SBMA and other neurodegenerative disorders caused by toxic proteins.

Category: Neuroscience