Journal: Molecular Therapy Advances
Article Title: Capsid-engineered AAV vector overcomes a key intracellular barrier and efficiently transduces spiral ganglion neurons in adult mice
doi: 10.1016/j.omta.2026.201669
Figure Lengend Snippet: Compared to AAV2, AAV.MPI shows distinct features, including enhanced uncoating, that lead to improved transduction efficiency (A) Intracellular vector copy numbers of AAV2 and AAV.MPI in HEI-OC1 cells after 24 h (GOI 5,000). DNA was extracted from whole lysates and analyzed by qPCR using transgene-specific primers. Bars, mean (SD), n = 3, ∗∗ p < 0.01, unpaired t test. (B) Transgene expression of AAV2 and AAV.MPI on HEI-OC1 cells after 24 h (GOI 5,000), analyzed by flow cytometry. Mean fluorescence intensity (MFI, median) was multiplied by the number of transgene-positive cells. Bars, mean (SD), n = 3, technical triplicates, ∗∗∗∗ p < 0.0001, unpaired t test. (C) Amount of intracellular vector copies of AAV2 and AAV.MPI in HEI-OC1 cells at the indicated time points (GOI 5,000). Genomic DNA was extracted from whole lysates and analyzed by qPCR using transgene-specific primers. Bars, mean (SD), n = 3, ns: not significant, ∗ p < 0.05, ∗∗ p < 0.01, two-way ANOVA with Bonferroni post hoc test. (D) Transgene expression of AAV2 and AAV.MPI in HEI-OC1 cells at the indicated time points (GOI 5,000), analyzed by flow cytometry. MFI median was multiplied by the number of transgene-positive cells for each time point and vector. Bars, mean (SD), n = 3, ns: not significant, ∗∗∗∗ p < 0.0001, two-way ANOVA with Bonferroni post hoc test. (E) In vitro uncoating in the nuclear fraction of HEI-OC1 cells treated with AAV2 and AAV.MPI after 12 and 24 h. Isolated DNA was treated with T5 exonuclease, and the ratio of episomal to total DNA was analyzed by qPCR using transgene-specific primers. Bars, mean (SD), n = 3, technical triplicates, ns: not significant, ∗∗ p < 0.01, two-way ANOVA with Bonferroni post hoc test. (F) Capsid destabilization assay for AAV2 and AAV.MPI. Vector preparations were incubated for 30 min at the specified temperatures, followed by native dot blot using the B1 antibody to detect disintegrated capsids. Representative image of n = 3. (G) Co-detection of vector DNA with vector capsids and vector capsid proteins. NHF cells were transduced with either AAV2 or AAV.MPI (GOI 20,000). At 24 hpt, cells were fixed and processed for multicolor IF analysis combined with FISH. Intact capsids (green) or capsid proteins (yellow) were detected using either an antibody against intact AAV2 capsids or an antibody against VP1, VP2, and VP3. AAV2 DNA (red) was detected with an Alexa Fluor (AF) 647-labeled, amine-modified DNA probe that binds to the AAV2 genome. Nuclei were counterstained with DAPI (blue). (H) Image-based quantification of the complete uncoating rate of AAV2 and AAV.MPI, determined as the ratio of capsid-DNA+/capsid+DNA+ of 50 individual cells for each vector. Bars, mean (SD), ∗∗∗ p < 0.001, unpaired t test. (J) Indirect uncoating assay of vector-treated (8E8 vg) murine cochlea at 1, 3, and 7 days post injection. Cochleae were isolated, DNA was extracted and treated with T5 exonuclease or mock-treated. Samples were analyzed by qPCR using transgene-specific primers and normalized to horseradish peroxidase ( hprt ) and control samples from not injected mice. Bars, mean (SD), fold-change of uncoating in AAV.MPI injected cochleae to AAV2, n = 3, ns: not significant, ∗∗ p < 0.01, two-way ANOVA with Bonferroni post hoc test. GOI, genomic particles of infection.
Article Snippet: For the generation of AAV.MPI and AAV.PPR encoding helper plasmids for AAV vector production, sense and antisense oligonucleotides representing the respective peptide sequencing, flanked by linkers and restriction enzymes cutting sites for AscI and MluI, were synthesized (Eurofins Genomics GmbH) and inserted into pRC’99 , to produce pRC.MPI and pRC.PPR, respectively.
Techniques: Transduction, Plasmid Preparation, Expressing, Flow Cytometry, Fluorescence, In Vitro, Isolation, Incubation, Dot Blot, Labeling, Modification, Injection, Control, Infection