Fig 2: Vascular stiffening and LOXL2 expression of the pulmonary artery after neonatal hypoxia exposure. (a) Tensile testing of pulmonary arteries of 60 day old mice exposed to postnatal hypoxia until day 11 compared with their normoxic littermate controls (n = 6, 3 males and 3 females; p < 0.0001). (b) Representative Western blots of LOXL2, Pro-LOX, and active-LOX protein levels. Densitometry analysis of (c) LOXL2, (d) Pro- LOX, and (e) Active LOX. n = 4–6 for Western blots; equal numbers of males and females. *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001 by 2-way ANOVA with Bonferroni post hoc analysis. Nx, normoxia, Hx, neonatal hypoxia from P1-P11.

Fig 3: LOXL2 mRNA and protein levels decrease rapidly in the heart after neonatal hypoxia exposure is terminated. (a) Loxl2 and (b) Lox gene expression in the heart with neonatal hypoxia exposure (Hx; fold change vs. normoxia (Nx) P11 hearts with 18S as housekeeping gene; 3 males, 3 females in each group). (c) Representative Western blots of LOXL2, Pro-LOX, and active-LOX protein levels in the ECM fraction of the heart. Densitometry analysis of (d) LOXL2, (e) Pro-LOX, and (f) Active LOX. For Western blots, n = 4–6; equal numbers of males and females; *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001 by 2-way ANOVA with Bonferroni post hoc analysis. Nx, normoxia, Hx, neonatal hypoxia from P1-P11.

Fig 4: The time course of LOXL2 mRNA and protein levels in the lungs following neonatal hypoxia exposure is distinct from the changes seen in isolated pulmonary arteries. (a) Loxl2 and (b) Lox gene expression in the lung of hypoxic neonates and normoxic littermate controls (fold change vs. P11 normoxia; 18S used as housekeeping gene; n = 6 per group; 3 male and 3 female; *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001 by 2-way ANOVA with Bonferroni post hoc analysis). (c) Representative Western blots of LOXL2 and Pro-LOX levels in the lung; active-LOX band was not detected. Densitometry analysis of (d) LOXL2 and (e) LOX protein in the ECM of lungs. n = 4–6 for Western blots, equal numbers of males and females; *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001 by 2-way ANOVA with Bonferroni post hoc analysis. Nx, normoxia, Hx, neonatal hypoxia from P1-P11.