Abstract
Background
Pulmonary arterial hypertension (PAH) is an incurable disease that urgently needs therapeutic approaches. Based on the therapeutic effects of fasudil and dichloroacetate (DCA) on PAH, we aimed to explore the effects and potential mechanism of a new salt, fasudil dichloroacetate (FDCA), in a SU5416 plus hypoxia (SuHx)-induced rat model of PAH.
Methods
The rat model of PAH was established by a single subcutaneous injection of SU5416 (20 mg/kg) followed by hypoxia (10% O2) exposure for 3 weeks. FDCA (15, 45, or 135 mg/kg i.g. daily) or the positive control, bosentan (100 mg/kg i.g. daily), were administered from the first day after SU5416 injection. After 3-week hypoxia, hemodynamic parameters, and histological changes of the pulmonary arterial vessels and right ventricle (RV) were assessed. Additionally, in vitro, the effects of FDCA (50 μM), compared with equimolar doses of fasudil, DCA, or fasudil+DCA, on the proliferation, migration, and contraction of human pulmonary arterial smooth muscle cell (PASMC) under hypoxia (1% O2) were evaluated.
Results
FDCA dose-dependently attenuated SuHx-induced PAH, with significant reductions in RV systolic pressure, pulmonary artery wall thickness, pulmonary vessel muscularization, perivascular fibrosis, as well as RV hypertrophy and fibrosis. In vitro, FDCA inhibited hypoxia-induced PASMC proliferation, migration, and contraction to a greater degree than fasudil or DCA alone by restoring mitochondrial function, reducing intracellular Ca2+, and inhibiting calcium/calmodulin-dependent kinase (Ca2+/CaMK) activity as well as Rho-kinase activity.
Conclusion
FDCA ameliorates hypoxia-induced PASMC dysfunction by inhibiting both Ca2+/CaMK and Rho-kinase signaling pathways, as well as maintaining mitochondrial homeostasis, thus alleviating SuHx-induced PAH.
Acknowledgments
This work was supported by the National Natural Science Foundation of China (grants 81273571, 81870054), and the Key Project of National Science & Technology for Infectious Diseases of China (grants 2015ZX10003001, 2018ZX10722301).
Ethics Approval
The study was approved by the Institutional Animal Care and Use Committee of Nanjing Medical University (NJMU/IACUC-2005021).
Disclosure
The authors report no conflicts of interest in this work.