Dual-vector gene therapy restores cochlear amplification and auditory sensitivity in a mouse model of DFNB16 hearing loss
Shubina-Oleinik et al. (2021) demonstrate the first successful dual-AAV gene therapy for DFNB16 hearing loss in a mouse model with targeted Strc deletion. The full-length STRC coding sequence (~5.3 kb) exceeds single-AAV packaging capacity; the team developed a dual-vector approach using AAV9-PHP.B to split and co-deliver the gene. Outcome: restored STRC expression in OHCs, normalized hair bundle morphology, substantially enhanced cochlear amplification, and improved auditory sensitivity. This is the foundational STRC-specific gene therapy proof-of-concept and the most direct evidence supporting h07’s gene replacement track.
Author note: This paper was cited as “Fang 2021” in earlier h07 notes and audit documents. The first author is Olga Shubina-Oleinik (Holt lab, Harvard). No author named “Fang” appears in the author list. Corrected 2026-04-25 (sweep phase). Holt JR (Jeffrey R. Holt) is the corresponding author.
Key finding
Dual-AAV9-PHP.B restores STRC expression and OHC function in Strc-knockout mice. This directly validates the dual-AAV delivery architecture for STRC in the exact target cells (OHCs) and confirms sensory hair cell transduction efficiency sufficient for functional rescue.
Numbers that matter
| Parameter | Value | Units | Source | Conditions |
|---|---|---|---|---|
| STRC cDNA size | ~5.3 | kb | Known STRC gene structure | Exceeds single AAV; dual-vector required |
| AAV serotype | AAV9-PHP.B | — | Abstract | Cochlear OHC delivery |
| Outcome: STRC expression | Restored | — | Abstract | OHCs in Strc-KO mice |
| Outcome: hair bundle morphology | Normalized | — | Abstract | OHC stereocilia |
| Outcome: cochlear amplification | Substantially enhanced | — | Abstract | DPOAE recovery (specific % not in abstract) |
| Outcome: auditory sensitivity | Improved | — | Abstract | ABR threshold reduction |
| Estimated DFNB16 patient pool | ~2.3 million | patients | Abstract | ~16% of genetic hearing loss |
Note: The h07 note states “50% mice show DPOAE recovery” as an interpretation; the abstract does not give this exact percentage. Full text (PMC8673757) should be consulted for specific recovery rates.
Limitations
- AAV9-PHP.B has well-characterized cochlear tropism but Anc80L65 (Wang 2025) may have superior OHC transduction efficiency.
- STRC KO mouse (full deletion) ≠ Misha’s compound heterozygous status (paternal deletion + maternal c.4976A>C point mutation). Gene replacement covers both alleles functionally.
- Neonatal injection likely (as in most cochlear gene therapy); adult efficiency uncertain.
- Gene replacement provides functional STRC but does not correct endogenous allele; prime/base editing of maternal allele is the parallel track (h07).
- “50% recovery” figure in h07 prose notes is an interpretation; exact numbers require PMC full text.
Connections
[source]Prime Editing for STRC — DFNB16 dual-AAV precedent; corrected from “Fang 2021” to Shubina-Oleinik 2021[source]STRC Cross-Hypothesis Verification Sweep 2026-04-25 — first-author corrected this turn[part-of]prime-editing — prime-editing topic parameter table[applies]h07 hub — dual-AAV STRC delivery proof; the gene replacement track that PE runs parallel to[see-also]2025-wang-abe-pou4f3-dfna15-anc80l65 — different gene, same cochlear dual-AAV therapeutic paradigm[about]Misha — DFNB16 patient; paternal deletion cannot be PE-corrected; replacement covers both alleles