Fasudil Dichloroacetate Alleviates SU5416/Hypoxia-Induced Pulmonary Arterial Hypertension by Ameliorating Dysfunction of Pulmonary Arterial Smooth Muscle Cells

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% O 2 ) 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% O 2 ) 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 Ca 2+ , and inhibiting calcium/calmodulin-dependent kinase (Ca 2+ /CaMK) activity as well as Rho-kinase activity. Conclusion: FDCA ameliorates hypoxia-induced PASMC dysfunction by inhibiting both Ca 2+ /CaMK and Rho-kinase signaling pathways, as well as maintaining mitochondrial homeostasis, thus alleviating SuHx-induced PAH.

DCA Protects against Oxidation Injury Attributed to Cerebral Ischemia‐Reperfusion by Regulating Glycolysis through PDK2‐PDH‐Nrf2 Axis

“…Previous studies have shown that DCA is a pharmacological agent that activates PDH by inhibiting PDK and also shows significant neuroprotective potential. The administration of DCA has been suggested to facilitate local lactic acid removal [ 32 ], tumor therapy [ 33 ], and pulmonary hypertension [ 34 ]. However, the protective effect, molecular mechanism, and blood-brain barrier permeability of DCA in cerebral IS and I/R injury have been rarely investigated.…”

FDCA Attenuates Neuroinflammation and Brain Injury after Cerebral Ischemic Stroke

“…Hence, we employed the ischemic stroke rat model to evaluate the effects of FDCA in cerebral ischemic injury (Figure S1A). First, we compared the therapeutic effects of FDCA, F, and DCA at equimolar dose alone or in combination in the rat tMCAO model using TTC staining and Longa test at 48 h post ischemia. , As demonstrated by Figure A,B, the rats in the tMCAO plus vehicle group displayed increased ischemic lesion volume and notably exacerbated neurological defects, whereas the FDCA administration (40 mg/kg) was capable of alleviating the ischemic lesion volume and neurological defects substantially. In addition, administration of FDCA displayed more effective therapeutic effects than F or DCA, alone or in combination in the rat tMCAO model, as evidenced by the less ischemic area in TTC staining and decreased scores in the Longa test (Figure A,B).…”

“…20 Under various physiological and pathological conditions, ROCK has been reported to phosphorylate the myosin light chain (MLC), myosin binding subunit of myosin phosphatase (MYPT), 20 collapsing response mediator protein 2 (CRMP2), ezrin/ radixin/moesin, 21 which in turn regulates a series of cellular functions, 22 including signaling, cell growth, cellular immune responses, and phagocytosis of immune cells. Particularly, fasudil, the ROCK inhibitor, 23,24 can mitigate MLC phosphorylation by inhibiting MYPT1 phosphorylation to attenuate cerebral vasospasm, 25,26 ultimately ameliorating the infarct area and promoting the long-term functional outcomes in the ischemic stroke. 23 In addition, due to lack of glucose and oxygen supply as well as diminished activity of pyruvate dehydrogenase (PDH) in the infarct area, 27 lactic acid metabolites are produced largely in the infarct region of brain, which subsequently arrest the tricarboxylic acid (TCA) cycle and lead to mitochondrial disorders.…”

“…Hence, inhibition of ROCK and PDK, as indicated by PDH phosphorylation, may exert a neuroprotective effect synergistically in an ischemic stroke. Fasudil dichloroacetate (FDCA), synthesized with fasudil and dichloroacetate, is a novel and potent synthetic water-soluble molecule and is capable of ameliorating pulmonary arterial hypertension by suppressing ROCK. , Additionally, FDCA has a higher blood concentration and longer half-life compared with the traditional fasudil hydrochloride according to the previous pharmacokinetic parameters. , Based on the above reasons, we hypothesize that FDCA might ameliorate ischemic stroke and improve long-term functional recovery via ROCK and PDK inhibition.…”

Mitochondrial Metabolism, Redox, and Calcium Homeostasis in Pulmonary Arterial Hypertension

“…Administration of a PDK inhibitor dichloroacetate (DCA) in IPAH patients leads to a reduction in mPAP, PVR, and improvement in RV function [ 49 ]. Several studies in PAH animal models have also demonstrated that administration of DCA blocks HIF-1α activation and promotes mitochondrial oxidative phosphorylation, thereby preventing and reversing PAH [ 48 , 50 , 51 , 52 ]. In addition to the regulation of glycolytic enzymes in response to hypoxia, HIF-1α can upregulate glucose transporter 1 (GLUT1) and hexokinase (HK) to both increase glucose uptake and retain it within the cell, further supporting a glycolytic shift [ 30 , 46 , 53 , 54 ].…”