Suppression of pain by gene editing
Provided herein are systems, compositions, kits, and methods for the suppression of pain (e.g., chronic pain). Genes encoding ion channels (e.g., SCN9A) responsible for the propagation pain signals in neurons (e.g., DRG neurons) may be edited using a genome editing agent (e.g., a nucleobase editor). In some embodiments, loss-of-function ion channel mutants are generated, leading to pain suppression. In some embodiments, the genome editing agent is administered locally to the site of pain or to the nerves responsible for propagation of the pain signal.
1. A method of editing a polynucleotide encoding an ion channel in a dorsal root ganglion (DRG) neuron, the method comprising contacting the ion channel-encoding polynucleotide with:
(i) a fusion protein comprising: (a) a guide nucleotide sequence-programmable DNA binding protein domain; and (b) a cytosine deaminase domain, wherein the fusion protein further comprises a uracil glycosylase inhibitor (UGI) domain; and
(ii) a guide nucleic acid molecule targeting the fusion protein of (i) to a target cytosine (C) base in the ion channel-encoding polynucleotide;
whereby the contacting results in deamination of the target C base by the fusion protein, resulting in a cytosine (C) to thymine (T) change in the ion channel-encoding polynucleotide; and
wherein the C to T change leads to a mutation in the ion channel that either introduces a premature stop codon in the ion channel-coding polynucleotide that leads to a truncated or non-functional ion channel or destabilizes ion-channel protein folding, or both.
2. The method of claim 1 , wherein the guide nucleotide sequence-programmable DNA binding protein domain is selected from the group consisting of: nuclease inactive Cas9 (dCas9) domains, nuclease inactive Cpf1 domains, nuclease inactive Argonaute domains, and variants thereof.
3. The method of claim 1 , wherein the cytosine deaminase domain comprises an apolipoprotein B mRNA-editing complex (APOBEC) family deaminase.
4. The method of claim 1 , wherein the cytosine deaminase domain is selected from the group consisting of APOBEC1 deaminase, APOBEC2 deaminase, APOBEC3A deaminase, APOBEC3B deaminase, APOBEC3C deaminase, APOBEC3D deaminase, APOBEC3F deaminase, APOBEC3G deaminase, APOBEC3H deaminase, APOBEC4 deaminase, activation-induced deaminase (AID), and pmCDA1.
5. The method of claim 4 , wherein the cytosine deaminase domain comprises the amino acid sequence of any one of SEQ ID NOs: 271-292, 303, or 2483-2494.
6. The method of claim 1 , wherein the UGI domain comprises the amino acid sequence of SEQ ID NO: 304.
7. The method of claim 1 , wherein the fusion protein comprises the amino acid sequence of any one of SEQ ID NOs: 296-302 and 2495.
8. The method of claim 1 , wherein the C to T change occurs in the coding region of the ion channel-encoding polynucleotide.
9. The method of claim 1 , wherein the mutation introduces a premature stop codon in the ion channel-coding sequence that leads to a truncated or non-functional ion channel.
10. The method of claim 1 , wherein the mutation destabilizes ion-channel protein folding.
11. The method of claim 1 , wherein the C to T change occurs at a C base-paired with the G base in a start codon (AUG).
12. The method of claim 1 , wherein the C to T change occurs in the non-coding region of the ion channel-encoding polynucleotide.
13. The method of claim 1 , wherein the ion channel is selected from the group consisting of: NaV1.7, NaV1.8, NaV1.9, NaV1.3, CaV3.2, HCN1, HCN2, and Ano1.
14. The method of claim 13 , wherein the ion channel is NaV1.7 encoded by the SCN9A gene.
15. The method of claim 1 , wherein a PAM sequence is either located 3′ of the C being changed or is located 5′ of the C being changed.
16. The method of claim 1 , wherein the DRG neuron is in a mammal.
17. The method of claim 16 , wherein the mammal is a human.
18. The method of claim 1 , wherein a nucleic acid construct encoding the fusion protein is delivered to the DRG neuron via a neurotropic viral delivery vector.
19. The method of claim 9 , wherein the mutation is installed at an amino acid position W188 of SEQ ID NO: 2434.
20. The method of claim 1 , wherein the guide nucleotide sequence-programmable DNA binding protein domain is an S. pyogenes Cas9 nickase, an S. aureus Cas9 nickase, or an S. aureus Cas9-KKH.
21. The method of claim 20 , wherein the guide nucleotide sequence-programmable DNA binding protein domain comprises an amino acid sequence having at least 95% sequence identity to any one of SEQ ID NOs: 3, 4, 268, or 2426-2428.
22. The method of claim 20 , wherein the guide nucleotide sequence-programmable DNA binding protein domain comprises the amino acid sequence of any of SEQ ID NOs: 3, 4, 268, or 2426-2428.
23. The method of claim 4 , wherein the cytosine deaminase domain comprises an amino acid sequence having at least 95% sequence identity to any one of SEQ ID NOs: 271-292, 303, or 2483-2494.
24. The method of claim 1 , wherein the guide nucleic acid molecule is selected from SEQ ID NOs: 834-1125 or 1273-1287.
25. A method of editing a polynucleotide encoding an ion channel in a DRG neuron, the method comprising contacting the ion channel-encoding polynucleotide with:
(i) a fusion protein comprising: (a) a guide nucleotide sequence-programmable DNA binding protein domain; and (b) a cytosine deaminase domain; and
(ii) a guide nucleic acid molecule targeting the fusion protein of (i) to a target C base in the ion channel-encoding polynucleotide;
whereby the contacting results in deamination of the target C base by the fusion protein, resulting in a C to T change in the ion channel-encoding polynucleotide, and
wherein the guide nucleic acid molecule is selected from SEQ ID NOs: 339-1456.
26. A method of editing a polynucleotide encoding an ion channel in a dorsal root ganglion (DRG) neuron, the method comprising contacting the ion channel-encoding polynucleotide with:
(i) a fusion protein comprising: (a) a guide nucleotide sequence-programmable DNA binding protein domain; and (b) a cytosine deaminase domain, wherein the fusion protein further comprises a uracil glycosylase inhibitor (UGI) domain; and
(ii) a guide nucleic acid molecule targeting the fusion protein of (i) to a target cytosine (C) base in the ion channel-encoding polynucleotide;
whereby the contacting results in deamination of the target C base by the fusion protein, resulting in a cytosine (C) to thymine (T) change in the ion channel-encoding polynucleotide; and
wherein the ion channel-encoding polynucleotide comprises the nucleic acid sequence of SEQ ID NO: 2435 and/or wherein the ion channel-encoding polynucleotide comprises a sequence containing the target C that comprises the nucleic acid sequence of any one of SEQ ID NOs: 1457-1503.
27. The method of claim 26 , wherein the ion channel comprises the amino acid sequence of SEQ ID NO: 2434.
28. A method of editing a polynucleotide encoding an ion channel in a dorsal root ganglion (DRG) neuron, the method comprising contacting the ion channel-encoding polynucleotide with:
(i) a fusion protein comprising: (a) a guide nucleotide sequence-programmable DNA binding protein domain; and (b) a cytosine deaminase domain, wherein the fusion protein further comprises a uracil glycosylase inhibitor (UGI) domain; and
(ii) a guide nucleic acid molecule targeting the fusion protein of (i) to a target cytosine (C) base in the ion channel-encoding polynucleotide, wherein the guide nucleic acid molecule is selected from SEQ ID NOs: 834-1125 or 1273-1287;
whereby the contacting results in deamination of the target C base by the fusion protein, resulting in a cytosine (C) to thymine (T) change in the ion channel-encoding polynucleotide.