SUL-150 Limits Vascular Remodeling and Ventricular Failure in Pulmonary Arterial Hypertension

Figures

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  Figure 1. SUL-150 reduces phenylephrine-induced vasoconstriction of the pulmonary artery in experimental PAH (day 21 post-monocrotaline administration). Phenylephrine induces vasoconstriction of the pulmonary artery ex vivo in sham (grey dots) and PAH (black dots) rats with equipotency (EC50) and similar efficacy (Emax). In the pulmonary arteries of sham rats, pre-incubation with 10−4 M SUL-150 for 30 min (grey open circles) decreases efficacy of vasoconstriction, but not the potency, as compared to vehicle control artery rings from sham rats (grey dots). In the pulmonary arteries of PAH rats, pre-incubation with SUL-150 (black open circles) decreases both the potency and efficacy of phenylephrine-induced vasoconstriction as compared to vehicle-treated artery rings (black dots). Data are expressed as mean ± S.D. of five rats per group (biological replicates). Experiments were performed in triplicate (technical replicates). Statistical evaluation was performed on individually determined EC50 and Emax values by ANOVA with Fisher’s LSD post hoc analyses. a p < 0.05 versus sham + vehicle; b p < 0.05 versus PAH + vehicle. Data are expressed as mean ± S.D. IVS = interventricular septum, LA =…

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  Figure 2. SUL-150 normalizes pulmonary artery pressure by reducing pulmonary artery remodeling (day 35 post-monocrotaline administration and treatment). Rats subjected to monocrotaline and aortocaval shunt placement develop pulmonary arterial hypertension as shown by an (A) increase in mean pulmonary arterial pressure, which is not affected by SUL-150 administration. N = 6–7 rats per group (plotted individually). Statistical evaluation was performed by ANOVA with Fisher’s LSD post hoc analyses. (B) In ex vivo pulmonary artery rings of PAH rats (black dots), phenylephrine-induced vasoconstriction with a higher potency and efficacy when compared to pulmonary artery rings from sham control rats (grey dots). SUL-150 administration in PAH rats (black open circles) normalized the efficacy of phenylephrine-induced vasoconstriction to the level of sham control rats. The potency of phenylephrine-induced vasoconstriction was unaltered in PAH rats that were administered with SUL-150 and had a similar potency to vehicle-treated rats. Data are expressed as mean ± S.D. of 6–7 rats per group (biological replicates) and were performed in triplicate (technical replicates). Statistical evaluation was…

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  Figure 3. SUL-150 reduces pulmonary vessel remodeling in PAH. Rats subjected to monocrotaline and aortocaval shunt placement develop (A) right pulmonary vessel remodeling as indicated by (B) a decreasing lumen area and increasing (C) occlusion score and (D) wall–lumen ratio. SUL-150 administration reduces these pathological changes. In vehicle-treated PAH rats, (E) the number of non-perfusable vessels (vessels Ø < 10 µm2) is increased as compared to sham control rats. SUL-150 administration decreases the number of non-perfusable vessels. N = 6–7 rats per group (plotted individually). Statistical evaluation was performed by ANOVA with Fisher’s LSD post hoc analyses. ns = non-significant.

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  Figure 4. SUL-150 mitigates right ventricular failure in PAH. Rats subjected to monocrotaline and aortocaval shunt placement develop right ventricular failure as indicated by a decrease in (A) heart rate and (B) cardiac output and increased (C) systolic right ventricular pressure and (D) diastolic right ventricular pressure. SUL-150 administration ameliorates these pathological changes to right ventricular function. Right ventricular failure in vehicle-treated PAH rats is associated with (E,F) cardiomyocyte hypertrophy, which is mitigated by SUL-150 administration. N = 6–7 rats per group (plotted individually). Statistical evaluation was performed by ANOVA with Fisher’s LSD post hoc analyses. (G) In vitro, SUL-150 dose-dependently decreases the potency and efficacy of phenylephrine to produce fluorescence by neonatal rat cardiomyocytes transduced with a virus encoding for a hypertrophy reporter. Data are expressed as mean ± S.D. of 4 biological replicates. Statistical evaluation was performed on individually determined EC50 and Emax values by ANOVA with Fisher’s LSD post hoc analyses. Furthermore, (H,I) right ventricular failure associates with increased fibrogenesis in vehicle-treated PAH…

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  Figure 5. SUL-150 mitigates mitochondrial dysfunction in the right ventricle. Rats subjected to monocrotaline and aortocaval shunt placement show mitochondrial loss and the development of mitochondrial dysfunction as shown by a (A) decrease in mitochondrial DNA content, (B) radical scavenging capacity, and (C) increased lipid peroxidation levels, culminating in (D) a reduction in ATP content. SUL-150 administration mitigates these changes in PAH rats. N = 6–7 rats per group (plotted individually). Experiments were performed in triplicate (technical replicates). Statistical evaluation was performed by ANOVA with Fisher’s LSD post hoc analyses. (E,F) Immunoblotting for molecular markers of mitogenesis (PGC1α and mtTFA) and mitophagy (PINK1 and Parkin) reveals that in vehicle-treated PAH rats, the expression of PINK1 and Parkin is reduced, indicative of disturbed mitophagy. SUL-150 administration to PAH rats maintains the expression of PINK1 and Parkin. N = 6–7 rats per group (plotted individually). Statistical evaluation was performed by ANOVA with Fisher’s LSD post hoc analyses.