Figure 2.

Time- and dose-dependent correction of MCK-Fxn heart phenotype after AAV9-CAG-FXN treatment

(A) Heart to body weight ratios at the time of necropsy: 57 days post-injection (dpi) for WT untreated (n = 15) and MCK-Fxn treated at 1 × 10¹³ vg/kg (n = 13), 14 dpi for MCK-Fxn saline group (n = 12), 26–57 dpi for MCK-Fxn treated at 3 × 10¹³ vg/kg (n = 11), and 20–26 dpi for MCK-Fxn treated at 1 × 10¹⁴ vg/kg (n = 12). (B) Vector genome copy (VGC) of AAV9-CAG-FXN in heart samples, as measured by ddPCR at the time of necropsy in WT untreated (n = 15), MCK-Fxn saline (n = 12), and MCK-Fxn treated at 1 × 10¹³ vg/kg (n = 12), 3 × 10¹³ vg/kg (n = 10), or 1 × 10¹⁴ vg/kg (n = 11). (C) mRNA expression of endogenous mouse Fxn and human FXN transgene in heart samples, as measured by ddPCR in WT untreated (n = 14), MCK-Fxn saline (n = 11), and MCK-Fxn treated at 1 × 10¹³ vg/kg (n = 13), 3 × 10¹³ vg/kg (n = 11), or 1 × 10¹⁴ vg/kg (n = 11). (D) Detection of Fxn transgene mRNA expression by in situ hybridization (ISH, upper panels) and human FXN protein by immunohistochemistry (IHC, lower panels) in heart sections. Scale bars, 300 μm. (E) Western blot analysis of mitochondrial and Fe-S client proteins from three mouse heart extracts from each group. Vinculin (VINC) was used as a loading control. (F) mRNA expression of cardiac dysfunction and FXN deficiency markers Nppa, Asns, Mthfd2, and Gdf15 as measured by ddPCR in WT untreated (n = 15), MCK-Fxn saline (n = 11), and MCK-Fxn treated at 1 × 10¹³ vg/kg (n = 13), 3 × 10¹³ vg/kg (n = 11), or 1 × 10¹⁴ vg/kg (n = 12). All data are mean ± SEM. ∗∗p < 0.01, ∗∗∗p < 0.001, ∗∗∗∗p < 0.0001.