2024 Hu — Engineering of the AAV-Compatible Hair Cell-Specific Small-Size Myo15 Promoter for Gene Therapy in the Inner Ear

Engineers AAV-compatible Myo15 promoter variants: 1157 bp (mid-Myo15) and 956 bp (mini-Myo15) truncated from 1611 bp native; drives HC-exclusive expression in IHC ~90-98% and OHC 69-77% via AAV-PHP.eB.

Citation

Hu SW, Lv J, Wang Z, Tang H, Wang H, Wang F, Wang D, Zhang J, Zhang L, Cao Q, Chen Y, Gao Z, Han Y, Wang W, Li G-L, Shu Y, Li H. “Engineering of the AAV-Compatible Hair Cell-Specific Small-Size Myo15 Promoter for Gene Therapy in the Inner Ear.” Research (Wash D C). 2024 Apr 25;7:0341. DOI: 10.34133/research.0341. PMID: 38665848. PMCID: PMC11045262.

NOTE: This is the correct source for the 956 bp and 1157 bp Myo15 promoter variants. The h03 scripts incorrectly cited “Zhao 2024” — this paper is by Hu et al. 2024, published in Research (Science AAAS). Shu lab (Yilai Shu) — same group as the Shu Yilai Shanghai mouse model. Open access via PMC.

TL;DR

Used a “multiple vectors in one AAV” barcoded strategy to screen truncated Myo15 promoter variants for hair-cell specificity and expression strength. Truncated the native 1,611 bp Myo15 promoter (by removing 88 bp and 201 bp UTRs and structural elements) to generate 1,157 bp (mid-Myo15) and 956 bp (mini-Myo15) variants. Both drive exclusive expression in cochlear and vestibular HCs when packaged in AAV-PHP.eB, with no CNS expression. Used with OTOF cDNA to rescue hearing in Otof-/- mice for at least 52 weeks.

Numbers that matter

ParameterValueUnitsSource (fig/table/text)Uncertainty
Native Myo15 promoter size1,611bpAbstract + textexact
Mid-Myo15 promoter size1,157bpAbstract + textexact — truncated by removing 88+201 bp UTRs and elements
Mini-Myo15 promoter size956bpAbstract + textexact — further truncated
Mini-Myo15 IHC efficiency (apical/mid/basal)~98%, ~91%, ~76%%Fig (per PMC text)estimated from bar graphs
Mid-Myo15 IHC efficiency~90% across regions%textapproximate
Mini-Myo15 OHC efficiency (apical/mid/basal)~77%, ~74%, ~69%%Fig (per PMC text)estimated from bar graphs
Mid-Myo15 OHC efficiency~69%, ~70%, ~62%%textestimated
AAV serotypeAAV-PHP.eBtext
Injection routeRound window membrane (RWM), neonatal P0-P2text
Hearing rescue duration≥52 weeksweeksAbstractsustained
Hearing rescue modelOtof-/- mice (DFNB9)textnot DFNB16/STRC
CNS expressionNonetext”not expressed in the CNS”
Molecular barcode length15 bpbptext

Method essentials

  • Screening platform: “multiple vectors in one AAV” — each candidate promoter plasmid gets a unique 15-bp barcode, co-packaged and injected as a pool, then ranked by RT-PCR + NGS
  • Model: C57BL/6 + Otof-/- mice, neonatal injection (P0-P2)
  • Payload for therapeutic validation: human OTOF cDNA under Myo15 promoters
  • Truncation: systematic deletion of 88 bp and 201 bp UTR segments from 1,611 bp native sequence
  • Readout: GFP reporter fluorescence + quantification of IHC/OHC transduction efficiency

Limitations

  • Myo15 promoters drive expression in BOTH IHC and OHC (not OHC-exclusive like B8)
  • OHC efficiency lower than IHC: mini-Myo15 OHC = ~69-77% vs IHC ~76-98%
  • B8 is OHC-exclusive with ~100% transduction; Myo15 promoters are HC-inclusive but lower OHC efficiency
  • AAV-PHP.eB used: different serotype from Anc80L65 used in OTOF clinical trials
  • No human OHC validation

Relevance to STRC

Identifies the correct source for the 956 bp and 1157 bp Myo15 promoter size values in h03 scripts. These values must be updated in script comments from “Zhao 2024” to “Hu et al. 2024 Research (Wash D C); DOI 10.34133/research.0341.”

For h03 specifically: Myo15 promoters are an alternative to B8 for OHC-targeting. Myo15 is less OHC-exclusive (also hits IHC) and has lower OHC efficiency (~69-77%) vs B8 (~100% OHC). B8 remains the preferred choice for OHC-exclusive STRC delivery. Myo15 promoters may be useful for dual-HC targeting if IHC expression is also desired.

Connections