Interactome of the long non-protein coding RNA (lncRNA) D4Z4 binding element-transcript (DBE-T)

Facioscapulohumeral muscular dystrophy (FSHD) is an inherited progressive neuromuscular disorder that afflicts both children and adults regardless of gender. FSHD is caused by aberrant gain of expression of the transcription factor DUX4, which triggers a pro-apoptotic transcriptional program leading to muscle wasting. As today, no cure or therapeutic option is available to FSHD patients. Given its centrality in FSHD, blocking DUX4 expression with small molecule drugs is an attractive option. We previously showed that the long non-coding RNA DBE-T is required for aberrant DUX4 expression in FSHD. Using affinity purification followed by proteomics, we identified the chromatin remodeling protein WDR5 as a novel DBE-T interactor and a key player required for the biological activity of the lncRNA. We found that WDR5 is required for the expression of DUX4 and its targets in primary FSHD muscle cells. Moreover, targeting WDR5 rescues both cell viability and myogenic differentiation of FSHD patient cells. Notably, comparable results were obtained by pharmacological inhibition of WDR5. Importantly, WDR5 targeting was safe to healthy donor muscle cells. Our results support a pivotal role of WDR5 in the activation of DUX4 expression identifying a druggable target for an innovative therapeutic approach for FSHD.