Verification of FBXL4 levels of AAV viral transfection in mouse hearts, livers, and kidneys, general biometric and echocardiographic properties of chow and ‘two-hit’ diet-induced HFpEF in mice. A: Illustrative experimental protocol; B: Representative immunoblots of FBXL4 in hearts, livers, and kidneys in AAV9-cTNT-Null and AAV9-cTNT-FBXL4 OE groups; C: Pooled data of FBXL4 in hearts, livers, and kidneys from AAV9-cTNT-Null and AAV9-cTNT-FBXL4 OE groups; D–E: FBXL4 intensity in mouse hearts detected using GFP fluorescence; F: Representative M-mode (upper), pulse-wave Doppler (middle) and tissue Doppler (bottom) images; G: Left ventricular end diastolic diameter (LVEDD); H: Left ventricular end systolic diameter (LVESD); I: Fractional shortening; J: Ejection fraction; K: Interventricular septal thickness in diastole (IVS, d); L: LV mass; M: E wave velocity; N: Mitral E/A ratio; O: e’ wave velocity; P: Mitral E/e’ ratio; Q: Running distance; R: Heart weight (HW) normalized to tibial length; S: Wet-to-dry lung weight ratio; and T–U: IPGTT curve and area under curve of intraperitoneal glucose tolerance test (IPGTT). Mean ± SEM, n = 6 mice per group for panel B–E, and 8–10 mice per group for others. Statistical significance was estimated using one-way ANOVA followed by a Tukey's post hoc analysis (two-way ANOVA for panel U). *p < 0.05, ***p < 0.001, ****p < 0.0001 between indicated groups.