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2010-10-21 - Colloque/Présentation - communication orale - Anglais - 1 page(s)

Vanderplanck Céline, Coppée Frédérique , Ansseau Eugénie , Tassin Alexandra , Laoudj-Chenivesse Dalila, Wilton D. Steve, Belayew Alexandra , "Suppression of DUX4 or DUX4c protein expression by antisense strategies as a therapeutic approach for FSHD." in FSH Society International Research Consortium & Research Planning Meeting, 8, 29, Boston, US-MA, 2010

  • Codes CREF : Biotechnologie (DI3800), Biologie moléculaire (DI3111), Acides nucléiques, synthèse des protéines (DI311A), Pathologies particulières (DI3370)
  • Unités de recherche UMONS : Biochimie métabolique et moléculaire (M122)
  • Instituts UMONS : Institut des Sciences et Technologies de la Santé (Santé)

Abstract(s) :

(Anglais) Our group has identified the double homeobox 4 (DUX4) gene within each unit of the D4Z4 repeat array at the FSHD locus (Gabriëls et al, 1999). It encodes a transcription factor with a double homeodomain that is expressed in FSHD but not control primary myoblasts (Kowaljow et al, 2007; Dixit et al, 2007). Using 5’ and 3’ RACE and RT-PCR, we determined that DUX4 transcription could initiate in any D4Z4 unit, but that stable mRNAs comprising the full DUX4 ORF only derived from the most distal unit and unexpectedly extended within the flanking pLAM region that provided an intron and a polyadenylation signal (Dixit et al, 2007). The presence of this signal is required to develop FSHD as recently shown by others (Lemmers et al, 2010). DUX4 activation at the FSHD locus initiates a global transcription deregulation cascade leading a.o. to muscle atrophy and differentiation defects (Dixit et al, 2007; Bosnakovski et al, 2008). Our group has also identified the homologous DUX4c gene located 42-kb upstream of the D4Z4 locus. It is expressed in muscles from healthy individuals but is also induced in FSHD. DUX4c over-expression in human myoblasts induced MYF5 and proliferation suggesting a role in muscle regeneration (Ansseau et al, 2009). No specific therapeutic strategies exist to date for FSHD. The rationale of this work is that inhibition of DUX4 or DUX4c expression should prevent the transcription deregulation cascade and restore a control myotube phenotype. In order to evaluate the impact of DUX4 or DUX4c inhibition, we have selected a few downstream biomarkers. These are typical FSHD deregulated genes (mu-crystallin, TP53,…) or characteristic myotubes phenotypes (atrophic/disorganized, see Barro et al, 2008). We found that forced DUX4 expression in control myoblasts leads to formation of atrophied myotubes. In contrast, forced DUX4c expression induced ß-catenin, abnormal accumulation of nuclei, and formation of disorganized myotubes. We have used different antisense approaches in human myoblast cultures to either induce messenger RNA destruction by RNA interference (siRNAs) or interfere with splicing by use of specific antisense oligomers (AOs). Decrease in DUX4 or DUX4c protein expression was confirmed by immunodetection on western blot and the biomarker levels changed as expected. These strategies seem promising and could contribute to future development of therapeutic approaches for FSHD.