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. 2021 Jun 1;131(11):e136459. doi: 10.1172/JCI136459

Figure 8. FXN deficiency promotes endothelial senescence and worsens PH in vivo.

Figure 8

(A) Diagram of conditional endothelial-specific Fxn knockout mouse model. Experiments compare male Fxn flox/flox (Fxnf/f) control mice to mice expressing a tamoxifen-dependent Cdh5(PAC)-ERT2+-Cre recombinase (EC Fxn–/–) following chronic hypoxia exposure (3 weeks, 10% O2). (B) RT-qPCR of Fxn expression in CD31+ cells isolated from lungs (n = 6–7/group). (C) Confocal microscopic imaging and quantification of endothelial γH2AX (red signal represented by white arrows), α-SMA (green), and DAPI (blue) in lung tissue (n = 3/group). (D and E) Relative Cdkn2a and Tnf mRNA by RT-qPCR in CD31+ cells isolated from mouse lungs (n = 6–7/group). (F) Plasma IL-6 protein expression (n = 9 versus n = 7). (G) Measurement of immunofluorescent staining of vessel-associated Cd11b+ myeloid cells (orange), α-SMA (green), and DAPI (blue) in lung tissue (n = 5–6/group). (H) Picrosirius red staining in parallel versus orthogonal light with quantification of orthogonal signal representative of vessel collagen deposition (n = 4/group). (I) RVSP (mmHg) measured by right heart catheterization (n = 11 versus n = 7). (J) Fulton index (RV/LV+S, %) (n = 11 versus n = 7). (K) Pearson correlation between relative Fxn and Cdkn2a transcript levels (n = 18). (L) Pearson correlation between Cdkn2a expression and RVSP (n = 18). Scale bars: 50 μm. Two-tailed Student’s t test was performed with error bars that reflect mean ± SD.