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Project description:Adenosine deaminase acting on RNA 1 (ADAR1) catalyzes the conversion of adenosine (A) to inosine (I) in double-stranded RNA (dsRNA), which is critical to prevent auto-inflammatory responses mediated by activation of the type I interferon (IFN) signaling. Here, we define the role of ADAR1-dependent RNA editing in interferon-β(IFNβ) activation and pulmonary artery smooth muscle cell (PASMC) remodeling in pulmonary arterial hypertension (PAH), a devastating disease leading to right heart failure and premature death. Methods: RNA editing levels were analyzed in human pulmonary artery smooth muscle cells (PASMCs) from idiopathic PAH (IPAH) patients versus healthy controls. A conditional transgenic line ADAR1SMC-KO was generated by knocking out ADAR1 selectively in α-smooth muscle actin-positive cells, followed by hypoxic exposure to induce PH. Results: PASMCs from IPAH patients displayed decreased levels of ADAR1 mRNA and protein, accompanied by reduced A-to-I editing compared to healthy PASMCs. ADAR1 knockdown in PASMCs upregulated MDA5, PKR, IFN-β and IFN-Stimulated Genes (ISGs). Compared with controls in vivo, hypoxic ADAR1SMC-KO mice developed severe PH, as evidenced by excessive vascular remodeling in distal arterioles and increased vascular leakage resulting in elevated right ventricular systolic pressure and right ventricular hypertrophy. Mechanistically, IFNβ signaling in ADAR1SMC-KO lungs induced the recruitment of inflammatory cells, including macrophages, which in turn enhanced PASMC proliferation and muscularization. Correspondingly, pharmacological treatment with PKR kinase inhibitor Imoxin decreased IFNβ thus attenuating the hypoxia-induced PH phenotype of ADAR1SMC-KO mice. Conclusions: ADAR1-dependent A-to-I RNA editing tempers IFN signaling in PASMCs. Pathologic reduction of ADAR1 in SMCs increased IFNβ activity, macrophage recruitment, and worsened PH, thus demonstrating a direct detrimental role of vascular innate immune responses in PH. Targeting PKR could be the new therapeutic strategy aimed at treating PAH.
2025-09-03 | GSE228134 | GEO
Project description:Adenosine deaminase acting on RNA 1 (ADAR1) catalyzes the conversion of adenosine (A) to inosine (I) in double-stranded RNA (dsRNA), which is critical to prevent auto-inflammatory responses mediated by activation of the type I interferon (IFN) signaling. Here, we define the role of ADAR1-dependent RNA editing in interferon-β(IFNβ) activation and pulmonary artery smooth muscle cell (PASMC) remodeling in pulmonary arterial hypertension (PAH), a devastating disease leading to right heart failure and premature death. Methods: RNA editing levels were analyzed in human pulmonary artery smooth muscle cells (PASMCs) from idiopathic PAH (IPAH) patients versus healthy controls. A conditional transgenic line ADAR1SMC-KO was generated by knocking out ADAR1 selectively in α-smooth muscle actin-positive cells, followed by hypoxic exposure to induce PH. Results: PASMCs from IPAH patients displayed decreased levels of ADAR1 mRNA and protein, accompanied by reduced A-to-I editing compared to healthy PASMCs. ADAR1 knockdown in PASMCs upregulated MDA5, PKR, IFN-β and IFN-Stimulated Genes (ISGs). Compared with controls in vivo, hypoxic ADAR1SMC-KO mice developed severe PH, as evidenced by excessive vascular remodeling in distal arterioles and increased vascular leakage resulting in elevated right ventricular systolic pressure and right ventricular hypertrophy. Mechanistically, IFNβ signaling in ADAR1SMC-KO lungs induced the recruitment of inflammatory cells, including macrophages, which in turn enhanced PASMC proliferation and muscularization. Correspondingly, pharmacological treatment with PKR kinase inhibitor Imoxin decreased IFNβ thus attenuating the hypoxia-induced PH phenotype of ADAR1SMC-KO mice. Conclusions: ADAR1-dependent A-to-I RNA editing tempers IFN signaling in PASMCs. Pathologic reduction of ADAR1 in SMCs increased IFNβ activity, macrophage recruitment, and worsened PH, thus demonstrating a direct detrimental role of vascular innate immune responses in PH. Targeting PKR could be the new therapeutic strategy aimed at treating PAH.
2025-09-03 | GSE228133 | GEO
Project description:Expression of nucleotide-binding oligomerization domain protein 2 (NOD2) is upregulated in pulmonary artery smooth muscle cells (PASMCs) during hypoxia. To investigate the involvement of NOD2 in the pulmonary vascular response to hypoxia, we subjected wild-type and NOD2-deficient mice to chronic normobaric hypoxic conditions. Compared to wild-type mice, NOD2-deficient mice developed severe pulmonary hypertension with exaggerated elevation of right ventricular systolic pressure, profound right ventricular hypertrophy and striking vascular remodeling after exposure to hypoxia. Pulmonary vascular remodeling in NOD2-deficient mice was characterized by increased PASMC proliferation. Furthermore, hypoxia-inducible factor-1α expression and Akt phosphorylation were upregulated in PASMCs from NOD2-deficient mice exposed to hypoxia. Our findings revealed that the absence of NOD2 exacerbated hypoxia-induced PASMC proliferation, pulmonary hypertension and vascular remodeling, but had no effect on PASMC migration or contractility.
| S-EPMC5849164 | biostudies-literature
Project description:ObjectivesCalcium independent group VIA phospholipase A(2) (iPLA(2)β) is up-regulated in vascular smooth muscle cells in some diseases, but whether the up-regulated iPLA(2)β affects vascular morphology and blood pressure is unknown. The current study addresses this question by evaluating the basal- and angiotensin II infusion-induced vascular remodeling and hypertension in smooth muscle specific iPLA(2)β transgenic (iPLA(2)β-Tg) mice.Method and resultsBlood pressure was monitored by radiotelemetry and vascular remodeling was assessed by morphologic analysis. We found that the angiotensin II-induced increase in diastolic pressure was significantly higher in iPLA(2)β-Tg than iPLA(2)β-Wt mice, whereas, the basal blood pressure was not significantly different. The media thickness and media∶lumen ratio of the mesenteric arteries were significantly increased in angiotensin II-infused iPLA(2)β-Tg mice. Analysis revealed no difference in vascular smooth muscle cell proliferation. In contrast, adenovirus-mediated iPLA(2)β overexpression in cultured vascular smooth muscle cells promoted angiotensin II-induced [(3)H]-leucine incorporation, indicating enhanced hypertrophy. Moreover, angiotensin II infusion-induced c-Jun phosphorylation in vascular smooth muscle cells overexpressing iPLA2β to higher levels, which was abolished by inhibition of 12/15 lipoxygenase. In addition, we found that angiotensin II up-regulated the endogenous iPLA(2)β protein in-vitro and in-vivo.ConclusionThe present study reports that iPLA(2)β up-regulation exacerbates angiotensin II-induced vascular smooth muscle cell hypertrophy, vascular remodeling and hypertension via the 12/15 lipoxygenase and c-Jun pathways.
| S-EPMC3282780 | biostudies-literature
Project description:Rationale: Glycolytic shift is implicated in the pathogenesis of pulmonary arterial hypertension (PAH). It remains unknown how glycolysis is increased and how increased glycolysis contributes to pulmonary vascular remodeling in PAH.Objectives: To determine whether increased glycolysis is caused by 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase 3 (PFKFB3) and how PFKFB3-driven glycolysis induces vascular remodeling in PAH.Methods: PFKFB3 levels were measured in pulmonary arteries of patients and animals with PAH. Lactate levels were assessed in lungs of animals with PAH and in pulmonary artery smooth muscle cells (PASMCs). Genetic and pharmacologic approaches were used to investigate the role of PFKFB3 in PAH.Measurements and Main Results: Lactate production was elevated in lungs of PAH rodents and in platelet-derived growth factor-treated PASMCs. PFKFB3 protein was higher in pulmonary arteries of patients and rodents with PAH, in PASMCs of patients with PAH, and in platelet-derived growth factor-treated PASMCs. PFKFB3 inhibition by genetic disruption and chemical inhibitor attenuated phosphorylation/activation of extracellular signal-regulated kinase (ERK1/2) and calpain-2, and vascular remodeling in PAH rodent models, and reduced platelet-derived growth factor-induced phosphorylation/activation of ERK1/2 and calpain-2, collagen synthesis and proliferation of PASMCs. ERK1/2 inhibition attenuated phosphorylation/activation of calpain-2, and vascular remodeling in Sugen/hypoxia PAH rats, and reduced lactate-induced phosphorylation/activation of calpain-2, collagen synthesis, and proliferation of PASMCs. Calpain-2 inhibition reduced lactate-induced collagen synthesis and proliferation of PASMCs.Conclusions: Upregulated PFKFB3 mediates collagen synthesis and proliferation of PASMCs, contributing to vascular remodeling in PAH. The mechanism is through the elevation of glycolysis and lactate that results in the activation of calpain by ERK1/2-dependent phosphorylation of calpain-2.
| S-EPMC6727156 | biostudies-literature
Project description:ObjectivesRegulated in development and DNA damage responses 1 (REDD1) is an important transcription factor regulating mitochondria homeostasis, which is the important pathological alteration of pulmonary hypertension (PH). However, it is unclear whether REDD1 regulates the PASMCs mitochondria homeostasis by the similar mechanism in pulmonary arterial remodeling induced by hypoxia.MethodsThe global REDD1-knockout rats (REDD1-KO) on Sprague-Dawley background were used to generate a chronic hypoxia model of PH. Right ventricular hypertrophy and vascular remodeling were detected after exposure to hypoxia. Additionally, proliferation, apoptosis, migration, mitochondria homeostasis, and autophagy were performed in vivo and in vitro.ResultsThe current research found that in human and experimental rats of PH, REDD1 expression is upregulated in the PASMCs. REDD1 gene knockout alleviated hypoxia PH and hemodynamic changes effectively and reversed hypoxic pulmonary vascular remodeling. In addition, REDD1 knockdown reduces the impairment of mitochondrial function caused by hypoxia in HPASMCs via autophagy inhibition, and this process may be regulated through the Parkin gene. Moreover, REDD1 knockdown can effectively inhibit the proliferation and migration of hypoxic PASMCs, and induce their apoptosis in vivo and in vitro.ConclusionsOur results suggested that REDD1 might be a potential target for improved pulmonary vascular remodeling in PH.
| S-EPMC8991113 | biostudies-literature
Project description:Patients with congenital heart disease (CHD) resulting in significant left-to-right shunting of blood are at risk for the development of pulmonary arterial hypertension (PAH). The underlying mechanism by which pulmonary overcirculation and shear stress lead to vascular remodeling remains unclear. Our study established a new "two-hit" murine model of severe pulmonary hypertension (PH) by combining left pneumonectomy and exposure to hypoxia (LP/Hx). Utilizing transgenic reporter lines, immunofluorescence staining, and advanced microscopy, we conducted cell-lineage tracing experiments for endothelial cells (ECs), smooth muscle cells (SMCs), and pericytes. We identified that SMCs is a primary contributor to distal arteriolar remodeling after LP/Hx. Subsequent qPCR analysis on isolated cells demonstrated that Cxcl12 was upregulated in both ECs and SMCs from LP/Hx animals. Likewise, CXCL12 was overexpressed in the SMC layer of arterioles in patients with acyanotic PAH-CHD. These findings provide novel insights into the contribution of SMCs and Cxcl12 to pulmonary flow-induced vascular remodeling. This newly established murine model of PH will serve as a new tool for research and targeted therapeutics for patients with PAH.
| S-EPMC11418988 | biostudies-literature
Project description:Emerging evidence suggests that caveolin-1 (Cav1) is associated with pulmonary arterial hypertension. MURC (also called Cavin-4) is a member of the cavin family, which regulates caveolar formation and functions together with caveolins. Here, we show that hypoxia increased Murc mRNA expression in the mouse lung, and that Murc-null mice exhibited attenuation of hypoxia-induced pulmonary hypertension (PH) accompanied by reduced ROCK activity in the lung. Conditional knockout mice lacking Murc in smooth muscle also resist hypoxia-induced PH. MURC regulates the proliferation and migration of pulmonary artery smooth muscle cells (PASMCs) through Rho/ROCK signalling. Cav1 suppresses RhoA activity in PASMCs, which is reversed by MURC. MURC binds to Cav1 and inhibits the association of Cav1 with the active form of Gα13, resulting in the facilitated association of the active form of Gα13 with p115RhoGEF. These results reveal that MURC has a function in the development of PH through modulating Rho/ROCK signalling.
| S-EPMC4996946 | biostudies-literature
Project description:BackgroundCyclooxygenase-2 (COX-2) is upregulated in pulmonary artery smooth muscle cells (PASMCs) during hypoxia and may play a protective role in the response of the lung to hypoxia. Selective COX-2 inhibition may have detrimental pulmonary vascular consequences during hypoxia.Methods and resultsTo investigate the role of COX-2 in the pulmonary vascular response to hypoxia, we subjected wild-type and COX-2-deficient mice to a model of chronic normobaric hypoxia. COX-2-null mice developed severe pulmonary hypertension with exaggerated elevation of right ventricular systolic pressure, significant right ventricular hypertrophy, and striking vascular remodeling after hypoxia. Pulmonary vascular remodeling in COX-2-deficient mice was characterized by PASMC hypertrophy but not increased proliferation. Furthermore, COX-2-deficient mice had significant upregulation of the endothelin-1 receptor (ET(A)) in the lung after hypoxia. Similarly, selective pharmacological inhibition of COX-2 in wild-type mice exacerbated hypoxia-induced pulmonary hypertension and resulted in PASMC hypertrophy and increased ET(A) receptor expression in pulmonary arterioles. The absence of COX-2 in vascular smooth muscle cells during hypoxia in vitro augmented traction forces and enhanced contractility of an extracellular matrix. Treatment of COX-2-deficient PASMCs with iloprost, a prostaglandin I(2) analog, and prostaglandin E(2) abrogated the potent contractile response to hypoxia and restored the wild-type phenotype.ConclusionsOur findings reveal that hypoxia-induced pulmonary hypertension and vascular remodeling are exacerbated in the absence of COX-2 with enhanced ET(A) receptor expression and increased PASMC hypertrophy. COX-2-deficient PASMCs have a maladaptive response to hypoxia manifested by exaggerated contractility, which may be rescued by either COX-2-derived prostaglandin I(2) or prostaglandin E(2).
| S-EPMC2586933 | biostudies-literature
Project description:RationaleVascular smooth muscle cell (SMC) phenotypic modulation is characterized by the downregulation of SMC contractile genes. Platelet-derived growth factor-BB, a well-known stimulator of SMC phenotypic modulation, downregulates SMC genes via posttranscriptional regulation. The underlying mechanisms, however, remain largely unknown.ObjectiveTo establish RNA editing as a novel mechanism controlling SMC phenotypic modulation.Methods and resultsPrecursor mRNAs (pre-mRNA) of SMC myosin heavy chain and smooth muscle α-actin were accumulated while their mature mRNAs were downregulated during SMC phenotypic modulation, suggesting an abnormal splicing of the pre-mRNAs. The abnormal splicing resulted from SMC marker pre-mRNA editing that was facilitated by adenosine deaminase acting on RNA 1 (ADAR1), an enzyme converting adenosines to inosines (A→I editing) in RNA sequences. ADAR1 expression inversely correlated with SMC myosin heavy chain and smooth muscle α-actin levels; knockdown of ADAR1 restored SMC myosin heavy chain and smooth muscle α-actin expression in phenotypically modulated SMC, and editase domain mutation diminished the ADAR1-mediated abnormal splicing of SMC marker pre-mRNAs. Moreover, the abnormal splicing/editing of SMC myosin heavy chain and smooth muscle α-actin pre-mRNAs occurred during injury-induced vascular remodeling. Importantly, heterozygous knockout of ADAR1 dramatically inhibited injury-induced neointima formation and restored SMC marker expression, demonstrating a critical role of ADAR1 in SMC phenotypic modulation and vascular remodeling in vivo.ConclusionsOur results unraveled a novel molecular mechanism, that is, pre-mRNA editing, governing SMC phenotypic modulation.
| S-EPMC4961590 | biostudies-literature