Multiexon skipping leading to an artificial DMD protein lacking amino acids from exons 45 through 55 could rescue up to 63% of patients with Duchenne muscular dystrophy

Béroud, Christophe; Tuffery‐Giraud, Sylvie; Matsuo, Masafumi; Hamroun, Dalil; Humbertclaude, Véronique; Monnier, Nicole; Moizard, Marie‐Pierre; Voelckel, Marie‐Antoinette; Calemard, Laurence Michel; Boisseau, Pierre; Blayau, Martine; Philippe, Christophe; Cossée, Mireille; Pages, M.; Rivier, François; Danos, Olivier; Garcı́a, Luis; Claustres, Mireille

doi:10.1002/humu.20428

Cited by 169 publications

(155 citation statements)

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“…The goal of treating a broader range of DMD patients with a single treatment has fostered interest in skipping multiple exons. In particular block skipping of exons 45-55 commends itself as a most promising approach (13,18). Exon 45-55 skipping is known to have two major advantages.…”

Section: Discussionmentioning

confidence: 99%

“…Exon 45-55 skipping is known to have two major advantages. First, it would be applicable to ∼63% of DMD patients with dystrophin deletion mutations (13). Second, the majority of individuals with a deletion of exons 45-55 of the DMD gene fall into the category of BMD patients with exceptionally mild, sometimes almost asymptomatic skeletal muscle involvement (12,13 (19).…”

Section: Discussionmentioning

confidence: 99%

“…First, it would be applicable to ∼63% of DMD patients with dystrophin deletion mutations (13). Second, the majority of individuals with a deletion of exons 45-55 of the DMD gene fall into the category of BMD patients with exceptionally mild, sometimes almost asymptomatic skeletal muscle involvement (12,13 (19). Such observations raise the hope that antisensemediated exon 45-55 skipping will have the potential not only to convert DMD patients to a mild BMD clinical phenotype but also to ameliorate the condition of some of the more severe BMD patients with mutations within the exon 45-55 hotspot region.…”

Section: Discussionmentioning

confidence: 99%

“…S1A). It has also been noted that exons 45-55 cover the main mutation "hotspot" of the DMD gene so that, theoretically, up to 63% of DMD patients with dystrophin deletion mutations could be treated if we were able to skip the entire exon 45-55 region, to generate an asymptomatic or remarkably mild BMD-like protein that appears to retain most of the function of the intact protein (13) (Fig. 1 A and B and Fig.…”

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Bodywide skipping of exons 45–55 in dystrophic mdx52 mice by systemic antisense delivery

Aoki

Yokota

Nagata

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

140

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Duchenne muscular dystrophy (DMD), the commonest form of muscular dystrophy, is caused by lack of dystrophin. One of the most promising therapeutic approaches is antisense-mediated elimination of frame-disrupting mutations by exon skipping. However, this approach faces two major hurdles: limited applicability of each individual target exon and uncertain function and stability of each resulting truncated dystrophin. Skipping of exons 45-55 at the mutation hotspot of the DMD gene would address both issues. Theoretically it could rescue more than 60% of patients with deletion mutations. Moreover, spontaneous deletions of this specific region are associated with asymptomatic or exceptionally mild phenotypes. However, such multiple exon skipping of exons 45-55 has proved technically challenging. We have therefore designed antisense oligo (AO) morpholino mixtures to minimize self-or heteroduplex formation. These were tested as conjugates with cell-penetrating moieties (vivo-morpholinos). We have tested the feasibility of skipping exons 45-55 in H2K-mdx52 myotubes and in mdx52 mice, which lack exon 52. Encouragingly, with mixtures of 10 AOs, we demonstrated skipping of all 10 exons in vitro, in H2K-mdx52 myotubes and on intramuscular injection into mdx52 mice. Moreover, in mdx52 mice in vivo, systemic injections of 10 AOs induced extensive dystrophin expression at the subsarcolemma in skeletal muscles throughout the body, producing up to 15% of wild-type dystrophin protein levels, accompanied by improved muscle strength and histopathology without any detectable toxicity. This is a unique successful demonstration of effective rescue by exon 45-55 skipping in a dystrophin-deficient animal model. personalized medicine | nucleic acid therapy | molecular therapy | oligonucleotides | gene therapy D uchenne muscular dystrophy (DMD), the commonest form of muscular dystrophy, is characterized by progressive deterioration of muscle function (1). DMD is caused mainly by frame-shifting deletion or nonsense mutations in the DMD gene, which encodes the protein dystrophin (2). At the milder end of the disease spectrum, Becker muscular dystrophy (BMD) is a form of dystrophin deficiency that presents with a large spectrum of severities, from borderline DMD to almost asymptomatic cases. BMD typically results from in-frame deletions in the DMD gene that allow the expression of limited amounts of an internally truncated but partly functional protein (3).Skipping of exons in DMD muscle so as to restore an in-frame and asymptomatic or very mild Becker-like transcript is among the more promising therapeutic approaches to treatment of DMD (4). To this end, systemic administration of antisense oligonucleotides (AOs) targeting specific exon(s) in the DMD gene has been shown to restore the reading frame and induce body-wide production of partially functional BMD-like dystrophin in mouse and dog models of DMD (5-7). Recently, phase I/II human clinical trials with AOs targeting exon 51 have been completed (8, 9).Although promising, future developm...

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

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Bodywide skipping of exons 45–55 in dystrophic mdx52 mice by systemic antisense delivery

Aoki

Yokota

Nagata

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

140

120

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“…These revertant dystrophins lack exon domains flanking the gene lesion in DMD patients (Fanin et al, 1995;Thanh et al, 1995) and the mutated exon 23 in the mdx mouse (Lu et al, 2000). Despite being internally truncated, dystrophin molecules found in BMD patients can be functional, as demonstrated by several families with in-frame deletions in the DMD gene, associated with elevated serum creatine kinase but displaying no clinical myopathy (e.g., deletions of exons 32-44, 48-51, or 48-53 [Melis et al, 1998], exon 48 [Morrone et al, 1997], exons 48-51 or 50-53 [Beggs et al, 1991], exons 45-55 [Beroud et al, 2007], or exons 50-51 [Lesca et al, 2007]). The efficacy of internally truncated dystrophins lacking an appreciable portion of the rod domain has also been demonstrated in transgenic mdx mice, and exploited to design so-called microdystrophins compatible with delivery by AAV vectors.…”

Section: Introduction Dmentioning

confidence: 99%