Modified U7 snRNAs for treatment of neuromuscular diseases
The present invention relates to a method to improve the activity of engineered U7 snRNAs used in the context of RNA-based therapeutics; particularly in exon skipping, exon inclusion, and mRNA eradication strategies. The resulting modified U7 snRNAs are useful for treating neuromuscular diseases, in particular Duchenne neuromuscular dystrophy, myotonic dystrophy DM1 and spinal muscular atrophy.
1. A modified huU7 snRNA, comprising the following elements bound covalently in the following order, from the 3′ end to the 5′ end:
a polynucleotide having the sequence of SEQ ID NO: 1,
a SmOPT domain having the sequence of SEQ ID NO: 2, and
at least one polynucleotide, said polynucleotide being capable of hybridizing with at least part of a target pre-mRNA, and
a kiss domain comprising at least three nucleotides,
wherein said kiss domain hybridizes with at least three nucleotides of the U7 loop,
wherein said U7 loop consists of nucleotides 12-20 of SEQ ID NO: 1.
2. The modified huU7 snRNA of claim 1 , wherein the said at least part of a target pre-mRNA is at least one splice site of one exon.
3. The modified huU7 snRNA of claim 2 , wherein the splice site is chosen from the group consisting of the 5′ donor site, the 3′ acceptor site, the branch point (BP) sequence, the exonic-splicing enhancer (ESE) sequence, the intronic-splicing enhancer (ISE) sequence, and the intronic silencer sequences (ISS) and the terminal stem loop (TSL).
4. The modified huU7 snRNA of claim 1 , wherein the at least part of a target pre-mRNA is a trinucleotide repeat expansion.
5. The modified huU7 snRNA of claim 4 , wherein the trinucleotide is CUG.
6. The modified huU7 snRNA of claim 4 , wherein the antisense comprises at least 15 repeats of the trinucleotide CAG.
7. The modified huU7 snRNA of claim 1 , wherein the said kiss domain has a sequence chosen between AAGU, GAGU, GGGU and AGGU or the said kiss domain has a sequence chosen between GCAGU, GAAGU, GCGGU, GGAGU, GAGGU and GGGGU.
8. A polynucleotide comprising a gene coding the modified huU7 snRNA of claim 1 .
9. The polynucleotide of claim 8 , wherein the said gene is fused to regulatory sequences.
10. The polynucleotide of claim 9 , wherein the said regulatory sequences comprise the human U7 promoter.
11. The polynucleotide of claim 10 , wherein the said promoter has the sequence of SEQ ID NO. 3.
12. The polynucleotide of claim 9 , wherein the said regulatory sequences comprise the huU7 snRNA gene downstream sequence.
13. The polynucleotide of claim 12 , wherein the said downstream sequence have the sequence of SEQ ID NO: 4.
14. A vector comprising the polynucleotide of claim 8 .
15. The vector of claim 14 , wherein said vector is chosen in the group consisting of plasmids, adenoviral vectors, associated-adenoviral vectors and lentiviral vectors.
16. An isolated eukaryotic cell transfected by the vector of claim 14 .
17. The cell of claim 16 , wherein the said cell is a skeletal muscle cell, a myoblast or a cell capable of muscle differentiation.
18. The cell of claim 16 , wherein said cell is an induced pluripotent stem cell.
19. A pharmaceutical composition comprising the vector of claim 14 or the cell of claim 16 .
20. A method for treating or preventing a neuromuscular disease, the said method comprising the step of administering the vector of claim 14 or the cell of claim 16 , and the said neuromuscular disease being selected in the group consisting of: Duchenne muscular dystrophy, Becker muscular dystrophy, limb girdle muscular dystrophy, congenital muscular dystrophy, facioscapulohumeral muscular dystrophy, myotonic muscular dystrophy, oculopharyngeal muscular dystrophy, distal muscular dystrophy, Emery-Dreifuss muscular dystrophy, and spinal muscular atrophy.
21. The method of claim 20 , wherein the neuromuscular disease is a neuromuscular dystrophy.
22. The method of claim 21 , wherein the neuromuscular dystrophy is Duchenne muscular dystrophy or myotonic dystrophy 1.
23. The method of claim 20 , wherein the neuromuscular disease is spinal muscular atrophy.
24. A method for restoring the function of a cellular protein by exon skipping, exon inclusion, or eradication of deleterious mRNAs, comprising the step of contacting a cell with the vector of claim 14 .