Differentiation and Growth-Arrest-Related lncRNA (DAGAR): Initial Characterization in Human Smooth Muscle and Fibroblast Cells.

Vascular smooth muscle cells (SMCs) can transition between a quiescent contractile or "differentiated" phenotype and a "proliferative-dedifferentiated" phenotype in response to environmental cues, similar to what in occurs in the wound healing process observed in fibroblasts. When dysregulated, these processes contribute to the development of various lung and cardiovascular diseases such as Chronic Obstructive Pulmonary Disease (COPD). Long non-coding RNAs (lncRNAs) have emerged as key modulators of SMC differentiation and phenotypic changes. In this study, we examined the expression of lncRNAs in primary human pulmonary artery SMCs (hPASMCs) during cell-to-cell contact-induced SMC differentiation. We discovered a novel lncRNA, which we named Differentiation And Growth Arrest-Related lncRNA (DAGAR) that was significantly upregulated in the quiescent phenotype with respect to proliferative SMCs and in cell-cycle-arrested MRC5 lung fibroblasts. We demonstrated that DAGAR expression is essential for SMC quiescence and its knockdown hinders SMC differentiation. The treatment of quiescent SMCs with the pro-inflammatory cytokine Tumor Necrosis Factor (TNF), a known inducer of SMC dedifferentiation and proliferation, elicited DAGAR downregulation. Consistent with this, we observed diminished DAGAR expression in pulmonary arteries from COPD patients compared to non-smoker controls. Through pulldown experiments followed by mass spectrometry analysis, we identified several proteins that interact with DAGAR that are related to cell differentiation, the cell cycle, cytoskeleton organization, iron metabolism, and the N-6-Methyladenosine (m6A) machinery. In conclusion, our findings highlight DAGAR as a novel lncRNA that plays a crucial role in the regulation of cell proliferation and SMC differentiation. This paper underscores the potential significance of DAGAR in SMC and fibroblast physiology in health and disease.

Effects of Pterostilbene on Heart and Lung Oxidative Stress Parameters in 2 Experimental Models of Cardiovascular Disease: Myocardial Infarction and Pulmonary Arterial Hypertension.

ABSTRACT: Myocardial infarction (MI) and pulmonary arterial hypertension (PAH) are 2 prevalent cardiovascular diseases. In both conditions, oxidative stress is associated with a worse prognosis. Pterostilbene (PTE), an antioxidant compound, has been studied as a possible therapy for cardiovascular diseases. This study aims to evaluate the effect of PTE on oxidative stress in the hearts of animals with MI and in the lungs of animals with PAH. Male Wistar rats were used in both models. In the MI model, the experimental groups were sham, MI, and MI + PTE. In the PAH model, the experimental groups were control, PAH, and PAH + PTE. Animals were exposed to MI through surgical ligation of the left coronary artery, or to PAH, by the administration of monocrotaline (60 mg/kg). Seven days after undergoing cardiac injury, the MI + PTE animals were treated with PTE (100 mg/kg day) for 8 days. After this, the heart was collected for molecular analysis. The PAH + PTE animals were treated with PTE (100 mg/kg day) for 14 days, beginning 7 days after PAH induction. After this, the lungs were collected for biochemical evaluation. We found that PTE administration attenuated the decrease in ejection fraction and improved left ventricle end-systolic volume in infarcted animals. In the PAH model, PTE improved pulmonary artery flow and decreased reactive oxygen species levels in the lung. PTE administration promoted protective effects in terms of oxidative stress in 2 experimental models of cardiac diseases: MI and PAH. PTE also improved cardiac function in infarcted rats and pulmonary artery flow in animals with PAH.

Effect of free and nanoemulsified ß-caryophyllene on monocrotaline-induced pulmonary arterial hypertension.

Pulmonary arterial hypertension (PAH) is characterized by increased pulmonary vascular resistance (PVR), right ventricular (RV) failure and premature death. Compounds with vasodilatory characteristics, such as ß-caryophyllene, could be promising therapeutics for PAH. This study aimed to determine the effects of free and nanoemulsified ß-caryophyllene in lung oxidative stress and heart function in PAH rats. Male Wistar rats (170 g, n = 6/group) were divided into four groups: control (CO), monocrotaline (MCT), monocrotaline + ß-caryophyllene (MCT-Bcar) and monocrotaline + nanoemulsion with ß-caryophyllene (MCT-Nano). PAH was induced by MCT (60 mg/kg i.p.), and 7 days later, treatment with ß-caryophyllene, either free or in a nanoemulsion (by gavage, 176 mg/kg/day) or vehicle was given for 14 days. Echocardiographic and hemodynamic measurements were performed, and after, the RV was collected for morphometry and the lungs for evaluation of oxidative stress, antioxidant enzymes, total sulfhydryl compounds, nitric oxide synthase (NOS) activity and endothelin-1 receptor expression. RV hypertrophy, increased PVR and RV systolic and diastolic pressures (RVSP and RVEDP, respectively) and increased mean pulmonary arterial pressure (mPAP) were observed in the MCT group. Treatment with both free and nanoemulsified ß-caryophyllene reduced RV hypertrophy, mPAP, RVSP and lipid peroxidation. The reduction in RVSP was more pronounced in the MCT-Nano group. Moreover, RVEDP decreased only in the MCT-Nano group. These treatments also increased superoxide dismutase, catalase and NOS activities and decreased endothelin-1 receptors expression. Both ß-caryophyllene formulations improved mPAP, PVR and oxidative stress parameters. However, ß-caryophyllene in a nanoemulsion was more effective in attenuating the effects of PAH.

Sulforaphane Improves Redox Homeostasis and Right Ventricular Contractility in a Model of Pulmonary Hypertension.

ABSTRACT: Pulmonary arterial hypertension (PAH) is characterized by increased pulmonary vascular resistance (PVR), imposing overload on the right ventricle (RV) and imbalance of the redox state. Our study investigated the influence of treatment with sulforaphane (SFN), found in cruciferous vegetables, on RV remodeling and redox homeostasis in monocrotaline (MCT)-induced PAH. Male Wistar rats were separated into 4 groups: control (CTR); CTR + SFN; MCT; and MCT + SFN. PAH induction was implemented by a single dose of MCT (60 mg/kg intraperitoneally). Treatment with SFN (2.5 mg/kg/day intraperitoneally) started on the seventh day after the MCT injection and persisted for 2 weeks. After 21 days of PAH induction, echocardiographic, hemodynamic, and oxidative stress evaluation was performed. The MCT group showed an increase in RV hypertrophy, RV systolic area, RV systolic, mean pulmonary artery pressure, and PVR and exhibited a decrease in the RV outflow tract acceleration time/ejection time ratio, RV fractional shortening, and tricuspid annular plane systolic excursion compared to CTR ( P < 0.05). SFN-treated PAH attenuated detrimental changes in tricuspid annular plane systolic excursion, mean pulmonary artery pressure, and PVR parameters. Catalase levels and the glutathione/Glutathione disulfide (GSSG) ratio were diminished in the MCT group compared to CTR ( P < 0.05). SFN increased catalase levels and normalized the glutathione/GSSG ratio to control levels ( P < 0.05). Data express the benefit of SFN treatment on the cardiac function of rats with PAH associated with the cellular redox state.

Pharmacological Agents and Potential New Therapies in Pulmonary Arterial Hypertension.

Pulmonary arterial hypertension (PAH) is a progressive disease characterized by an imbalance between vasoactive mediators, which causes vascular remodeling, increased pulmonary vascular resistance, and right ventricular overload, ultimately leading to heart failure and death. A metabolic theory has been suggested to explain the pathophysiology of PAH whereby abnormalities in mitochondrial biogenesis can trigger a hyperproliferative and apoptosis-resistant phenotype in cardiopulmonary and malignant cells, leading to mitochondrial dysfunction, which in turn causes the Warburg effect. This can culminate in the mitophagy of pulmonary vessels and cardiomyocytes. The present narrative review focuses on the pathophysiology of PAH, the pharmacological agents currently available for its treatment, and promising and challenging areas of therapeutic investigation.

The novel roles of YULINK in the migration, proliferation and glycolysis of pulmonary arterial smooth muscle cells: implications for pulmonary arterial hypertension.

BACKGROUND: Abnormal remodeling of the pulmonary vasculature, characterized by the proliferation and migration of pulmonary arterial smooth muscle cells (PASMCs) along with dysregulated glycolysis, is a pathognomonic feature of pulmonary arterial hypertension (PAH). YULINK (MIOS, Entrez Gene: 54468), a newly identified gene, has been recently shown to possess pleiotropic physiologic functions. This study aims to determine novel roles of YULINK in the regulation of PAH-related pathogenesis, including PASMC migration, proliferation and glycolysis. RESULTS: Our results utilized two PAH-related cell models: PASMCs treated with platelet-derived growth factor (PDGF) and PASMCs harvested from monocrotaline (MCT)-induced PAH rats (PAH-PASMCs). YULINK modulation, either by knockdown or overexpression, was found to influence PASMC migration and proliferation in both models. Additionally, YULINK was implicated in glycolytic processes, impacting glucose uptake, glucose transporter 1 (GLUT1) expression, hexokinase II (HK-2) expression, and pyruvate production in PASMCs. Notably, YULINK and GLUT1 were observed to colocalize on PASMC membranes under PAH-related pathogenic conditions. Indeed, increased YULINK expression was also detected in the pulmonary artery of human PAH specimen. Furthermore, YULINK inhibition led to the suppression of platelet-derived growth factor receptor (PDGFR) and the phosphorylation of focal adhesion kinase (FAK), phosphoinositide 3-kinase (PI3K), and protein kinase B (AKT) in both cell models. These findings suggest that the effects of YULINK are potentially mediated through the PI3K-AKT signaling pathway. CONCLUSIONS: Our findings indicate that YULINK appears to play a crucial role in the migration, proliferation, and glycolysis in PASMCs and therefore positioning it as a novel promising therapeutic target for PAH.

Simvastatin protects against intestinal ischemia/reperfusion-induced pulmonary artery dysfunction.

AIMS: The lung is an important target organ damage in intestinal ischemia/reperfusion (II/R), but mechanisms involved in II/R-induced pulmonary artery (PA) dysfunction, as well as its treatment, are not clear. The present study aimed to investigate the mechanisms involved in the II/R-induced PA dysfunction and a possible protective role of acute simvastatin pretreatment. MAIN METHODS: Male Wistar rats were subjected to occlusion of the superior mesenteric artery for 45 min followed by 2 h reperfusion (II/R) or sham-operated surgery (sham). In some rats, simvastatin (20 mg/kg, oral gavage) was administrated 1 h before II/R. KEY FINDINGS: II/R reduced acetylcholine-induced relaxation and phenylephrine-induced contraction of PA segments, which were prevented by acute simvastatin pretreatment in vivo or restored by inducible nitric oxide synthase (iNOS) inhibition in situ with 1400 W. Elevated reactive oxygen species (ROS) levels and higher nuclear translocation of nuclear factor kappa B (NFκB) subunit p65 were observed in PA of II/R rats and prevented by simvastatin. Moreover, simvastatin increased superoxide dismutase (SOD) activity and endothelial nitric oxide synthase (eNOS) expression in PA of the II/R group as well as prevented the increased levels of interleukin (IL)-1ß and IL-6 in lung explants following II/R. SIGNIFICANCE: The study suggests that pretreatment with a single dose of simvastatin prevents the II/R-induced increase of inflammatory factors and oxidative stress, as well as PA endothelial dysfunction and adrenergic hyporreactivity. Therefore, acute simvastatin administration could be therapeutic for pulmonary vascular disease in patients suffering from intestinal ischemic events.

Impact of Zinc on Oxidative Signaling Pathways in the Development of Pulmonary Vasoconstriction Induced by Hypobaric Hypoxia.

Hypobaric hypoxia is a condition that occurs at high altitudes (>2500 m) where the partial pressure of gases, particularly oxygen (PO2), decreases. This condition triggers several physiological and molecular responses. One of the principal responses is pulmonary vascular contraction, which seeks to optimize gas exchange under this condition, known as hypoxic pulmonary vasoconstriction (HPV); however, when this physiological response is exacerbated, it contributes to the development of high-altitude pulmonary hypertension (HAPH). Increased levels of zinc (Zn2+) and oxidative stress (known as the "ROS hypothesis") have been demonstrated in the vasoconstriction process. Therefore, the aim of this review is to determine the relationship between molecular pathways associated with altered Zn2+ levels and oxidative stress in HPV in hypobaric hypoxic conditions. The results indicate an increased level of Zn2+, which is related to increasing mitochondrial ROS (mtROS), alterations in nitric oxide (NO), metallothionein (MT), zinc-regulated, iron-regulated transporter-like protein (ZIP), and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase-induced protein kinase C epsilon (PKCε) activation in the development of HPV. In conclusion, there is an association between elevated Zn2+ levels and oxidative stress in HPV under different models of hypoxia, which contribute to understanding the molecular mechanism involved in HPV to prevent the development of HAPH.

let-7b-5p suppresses the proliferation and migration of pulmonary artery smooth muscle cells via down-regulating IGF1.

OBJECTIVES: Some previous studies indicated that the excessive proliferation and migration of Pulmonary Artery Smooth Muscle Cells (PASMCs) could be observed in pulmonary artery intima after Pulmonary Embolism (PE) occurred. In addition, recent studies identified some miRNAs that are differentially expressed in the blood of PE patients, which might be used as a diagnostic biomarker for PE, including let-7a-5p, let-7b-5p, and miR-150-5p. Hence, the authors sought to explore the effects of let-7b-5p in PASMC proliferation and migration and the corresponding regulatory mechanism. METHODS: Platelet-Derived Growth Factor (PDGF) was utilized to induce the hyper-proliferation model in PASMCs. The mRNA and protein expression levels were detected by RT-qPCR and western blot, respectively. The proliferation of PASMCs was evaluated by the detection of PCNA expression, as well as CCK-8 and Edu assays. Wound healing and Transwell assays were exploited to assess the migration ability of PASMCs. The targets of let-7b-5p were predicted based on two bioinformatics online tools. Dual-luciferase and Ago2 pull-down assays were applied to confirm the interaction between let-7b-5p and IGF1. RESULTS: 40 ng/mL PDGF was selected as the optimal concentration to induce PASMCs. let-7b-5p mimics suppressed the proliferation and migration of PDGF-induced PASMCs, while let-7b-5p inhibitor led to the opposite result. In further mechanism exploration, IGF1 was predicted and confirmed as the direct target gene of let-7b-5p. The promotion role of IGF1 overexpression on the proliferation and migration of PDGF-induced PASMCs was dramatically countered by let-7b-5p mimics. CONCLUSION: let-7b-5p prohibits the proliferation and migration of PDGF-induced PASMCs by modulating IGF1.

Pulmonary Hypertension in Obese Mice Is Accompanied by a Reduction in PPAR-γ Expression in Pulmonary Artery.

Obesity and insulin resistance (IR) are well-studied risk factors for systemic cardiovascular disease, but their impact on pulmonary hypertension (PH) is not well clarified. This study aims to investigate if diet-induced obesity induces PH and if peroxisome-proliferator-activated receptor (PPAR-γ) and/or endoplasmic reticulum (ER) stress are involved in this process. Mice were maintained on a high-fat diet (HFD) for 4 months, and IR and PH were confirmed. In a separate group, after 4 months of HFD, mice were treated with pioglitazone (PIO) or 4-phenylbutyric acid for the last month. The results demonstrated that HFD for at least 4 months is able to increase pulmonary artery pressure, which is maintained, and this animal model can be used to investigate the link between IR and PH, without changes in ER stress in the pulmonary artery. There was also a reduction in circulating adiponectin and in perivascular adiponectin expression in the pulmonary artery, associated with a reduction in PPAR-γ expression. Treatment with PIO improved IR and PH and reversed the lower expression of adiponectin and PPAR-γ in the pulmonary artery, highlighting this drug as potential benefit for this poorly recognized complication of obesity.

Anti-Inflammatory Effect of Allicin Associated with Fibrosis in Pulmonary Arterial Hypertension.

Pulmonary arterial hypertension (PAH) is characterized by pulmonary vascular remodeling. Recent evidence supports that inflammation plays a key role in triggering and maintaining pulmonary vascular remodeling. Recent studies have shown that garlic extract has protective effects in PAH, but the precise role of allicin, a compound derived from garlic, is unknown. Thus, we used allicin to evaluate its effects on inflammation and fibrosis in PAH. Male Wistar rats were divided into three groups: control (CON), monocrotaline (60 mg/kg) (MCT), and MCT plus allicin (16 mg/kg/oral gavage) (MCT + A). Right ventricle (RV) hypertrophy and pulmonary arterial medial wall thickness were determined. IL-1ß, IL-6, TNF-α, NFκB p65, Iκß, TGF-ß, and α-SMA were determined by Western blot analysis. In addition, TNF-α and TGF-ß were determined by immunohistochemistry, and miR-21-5p and mRNA expressions of Cd68, Bmpr2, and Smad5 were determined by RT-qPCR. Results: Allicin prevented increases in vessel wall thickness due to TNF-α, IL-6, IL-1ß, and Cd68 in the lung. In addition, TGF-ß, α-SMA, and fibrosis were lower in the MCT + A group compared with the MCT group. In the RV, allicin prevented increases in TNF-α, IL-6, and TGF-ß. These observations suggest that, through the modulation of proinflammatory and profibrotic markers in the lung and heart, allicin delays the progression of PAH.

Beneficial effects of melatonin on prostanoids pathways in pulmonary hypertensive neonates.

Pulmonary arterial hypertension of the newborn (PAHN) is a syndrome caused by chronic hypoxia, characterized by decreased vasodilator function, a marked vasoconstrictor activity, proliferation of smooth muscle cells (SMC) and thickening of the extracellular matrix in the pulmonary circulation, among other characteristics. Prostaglandins are derived from the arachidonic acid (AA) metabolism and are important regulators of pulmonary vascular tone. Since hypoxia induces oxidative stress and has been related to PAHN, a postnatal treatment with melatonin has been proposed due to its antioxidant properties. Here, we determined the effects of melatonin on pulmonary vascular homeostasis given by prostanoids. Ten PAHN newborn lambs were divided in two groups and treated either with vehicle or melatonin. After 1 week of treatment, we assessed pulmonary vascular prostanoids function and expression by wire myography, RT-PCR, Western Blot and immunohistochemistry. Melatonin improved in vivo and ex vivo pulmonary vasodilation. This was associated with an increased function and expression of vasodilator prostanoids at the expense of vasoconstrictor prostanoids. Our study demonstrates for the first time that melatonin may enhance the vasodilator prostanoid pathway in PAHN.

Determination of dopamine, noradrenaline, and adrenaline in Krebs-Henseleit solution by liquid chromatography coupled with tandem mass spectrometry and measurement of their basal release from Chelonoidis carbonaria aortae in vitro.

This study presented for the first time the development and validation of a sensitive method for quantification of dopamine, noradrenaline, and adrenaline in Krebs-Henseleit solution by LC-tandem mass spectrometry. Aliquots of 2.0 mL calibrators, quality controls, and samples of Krebs-Henseleit solution incubated with tortoise's aortic ring for 30 min were extracted by solid-phase extraction. Catecholamine separation was achieved on a 100 × 4.6 mm LiChrospher RP-8 column and the quantification was performed by a mass spectrometer equipped with an electrospray interface operating in positive ion mode. The run time was 4 min and the calibration curve was linear over the range of 0.1-20.0 ng/mL. The method was applied to the measurement of basal release of dopamine, noradrenaline, and adrenaline from the tortoise Chelonoidis carbonaria aortae in vitro. One aortic ring (30 mm) per tortoise (n = 5) was incubated for 30 min in a 5 mL organ bath filled with Krebs-Henseleit solution. The method demonstrated sensitivity, precision, and accuracy enough for its application in the measurement of basal release of these catecholamines from C. carbonaria aortic rings in vitro. The mean (standard deviation) concentrations of dopamine, noradrenaline, and adrenaline were 3.48 (2.55) ng/mL, 1.40 (0.57) ng/mL, and 1.87 (1.09) ng/mL, respectively.

Therapeutic Benefit of the Association of Lodenafil with Mesenchymal Stem Cells on Hypoxia-induced Pulmonary Hypertension in Rats.

Pulmonary arterial hypertension (PAH) is characterized by the remodeling of pulmonary arteries, with an increased pulmonary arterial pressure and right ventricle (RV) overload. This work investigated the benefit of the association of human umbilical cord mesenchymal stem cells (hMSCs) with lodenafil, a phosphodiesterase-5 inhibitor, in an animal model of PAH. Male Wistar rats were exposed to hypoxia (10% O2) for three weeks plus a weekly i.p. injection of a vascular endothelial growth factor receptor inhibitor (SU5416, 20 mg/kg, SuHx). After confirmation of PAH, animals received intravenous injection of 5.105 hMSCs or vehicle, followed by oral treatment with lodenafil carbonate (10 mg/kg/day) for 14 days. The ratio between pulmonary artery acceleration time and RV ejection time reduced from 0.42 ± 0.01 (control) to 0.24 ± 0.01 in the SuHx group, which was not altered by lodenafil alone but was recovered to 0.31 ± 0.01 when administered in association with hMSCs. RV afterload was confirmed in the SuHx group with an increased RV systolic pressure (mmHg) of 52.1 ± 8.8 normalized to 29.6 ± 2.2 after treatment with the association. Treatment with hMSCs + lodenafil reversed RV hypertrophy, fibrosis and interstitial cell infiltration in the SuHx group. Combined therapy of lodenafil and hMSCs may be a strategy for PAH treatment.

Expressions of TOLL-like receptor 4 (TLR-4) and matrix metalloproteinase 9 (MMP-9)/Tissue inhibitor of metalloproteinase 1 (TIMP-1) in pulmonary blood vessels with chronic obstructive pulmonary diseases and their relationships with pulmonary vascular remodelling.

OBJECTIVE: This study aims at investigating the expressions of TOLL-like receptor 4 (TLR-4) and matrix metalloproteinase 9 (MMP-9)/ tissue inhibitor of metalloproteinase 1 (TIMP-1) in pulmonary blood vessels with chronic obstructive pulmonary disease (COPD) and their relationships with pulmonary vascular remodelling (PVR). METHODS: 60 para-tumour tissues were divided into the COPD group and the control group (n=30); the inflammations, pulmonary artery wall area/total artery area (WA%), and wall thickness/vascular outer diameter (WT%) were compared. The expressions of TLR-4, MMP-9/TIMP-1, and PCNA in pulmonary vascular smooth muscle cells were detected, and their relationships with PVR were then analysed. RESULTS: The inflammations (1.6±0.8), WA% (44.0±6.4), and WT% (27.3±3.3) in the COPD group were higher than in the control group (0.3±0.5, 26.1±2.8, 15.6±1.8), and the expressions of TLR-4 (31.4±147) and MMP-9/TIMP-1 (2.2±2.6) were increased compared to the control group (4.7±4.5, 1.9±12). Correlation analysis: TLR-4 and MMP-9/TIMP-1 were positively correlated with the inflammations (r=0.18, P<0.01), WA% (r=0.68, P<0.01), and WT% (r=0.73, P<0.01), as well as positively correlated with the expression of PCNA (r=0.44, P<0.01); the upregulation of TLR-4 was positively correlated with the expressions of MMP-9 and TIMP-1. CONCLUSIONS: The upregulation of TLR-4 in the pulmonary arterial smooth muscle cells of COPD patients could promote the inflammations and the MMP-9 expression, thus causing abnormal degradation of extracellular matrix, so it played an important role in the process of PVR.

Chronic iron overload induces vascular dysfunction in resistance pulmonary arteries associated with right ventricular remodeling in rats.

Although iron excess is toxic to the vasculature and even that pulmonary hypertension has been reported in this scenario, the role of iron overload per se remains to be clarified. This study aimed to test the effects of chronic iron-overload in rats on the morphophysiology of resistance pulmonary arteries (RPA) and right ventricle (RV) remodeling. Rats were injected with saline or iron-dextran (10, 100 and 200 mg/kg/day i.p.) for 28 days. Our results indicated increased circulating iron with significant lung deposits. Moreover, rats treated with the highest dose exhibited RV dysfunction and hypertrophy; inward remodeling and increased vasoconstriction of the RPA. Vascular hyperreactivity was accompanied by reduced nitric oxide (NO), and was reversed by incubation with Dimethylsulfoxide, Catalase and Tempol. The NADPH oxidase subunit gp91phox was increased due to iron-overload, and incubation with angiotensin II type-1 receptor (AT1) antagonist losartan not only reduced oxidative stress but also restored vascular function. Thus, we concluded that AT1 pathway plays a role in pulmonary vascular dysfunction by increasing oxidative stress and reducing NO bioavailability, thereby contributing to vascular remodeling and pulmonary hypertension of iron-overload. This finding should instigate future studies on the beneficial impacts of in vivo blockade of AT1 receptor under iron overload.

Cardioprotection Induced by Activation of GPER in Ovariectomized Rats With Pulmonary Hypertension.

Pulmonary hypertension (PH) is a disease of women (female-to-male ratio 4:1), and is associated with cardiac and skeletal muscle dysfunction. Herein, the activation of a new estrogen receptor (GPER) by the agonist G1 was evaluated in oophorectomized rats with monocrotaline (MCT)-induced PH. Depletion of estrogen was induced by bilateral oophorectomy (OVX) in Wistar rats. Experimental groups included SHAM or OVX rats that received a single intraperitoneal injection of MCT (60 mg/kg) for PH induction. Animals received s.c. injection of either vehicle or G1, a GPER agonist, (400 µg/kg/day) for 14 days after the onset of disease. Rats with PH exhibited exercise intolerance and cardiopulmonary alterations, including reduced pulmonary artery flow, biventricular remodeling, and left ventricular systolic and diastolic dysfunction. The magnitude of these PH-induced changes was significantly greater in OVX versus SHAM rats. G1 treatment reversed both cardiac and skeletal muscle functional aberrations caused by PH in OVX rats. G1 reversed PH-related cardiopulmonary dysfunction and exercise intolerance in female rats, a finding that may have important implications for the ongoing clinical evaluation of new drugs for the treatment of the disease in females after the loss of endogenous estrogens.

Expressions of TOLL-like receptor 4 (TLR-4) and matrix metalloproteinase 9 (MMP-9)/Tissue inhibitor of metalloproteinase 1 (TIMP-1) in pulmonary blood vessels with chronic obstructive pulmonary diseases and their relationships with pulmonary vascular remodelling

SUMMARY OBJECTIVE: This study aims at investigating the expressions of TOLL-like receptor 4 (TLR-4) and matrix metalloproteinase 9 (MMP-9)/ tissue inhibitor of metalloproteinase 1 (TIMP-1) in pulmonary blood vessels with chronic obstructive pulmonary disease (COPD) and their relationships with pulmonary vascular remodelling (PVR). METHODS: 60 para-tumour tissues were divided into the COPD group and the control group (n=30); the inflammations, pulmonary artery wall area/total artery area (WA%), and wall thickness/vascular outer diameter (WT%) were compared. The expressions of TLR-4, MMP-9/TIMP-1, and PCNA in pulmonary vascular smooth muscle cells were detected, and their relationships with PVR were then analysed. RESULTS: The inflammations (1.6±0.8), WA% (44.0±6.4), and WT% (27.3±3.3) in the COPD group were higher than in the control group (0.3±0.5, 26.1±2.8, 15.6±1.8), and the expressions of TLR-4 (31.4±147) and MMP-9/TIMP-1 (2.2±2.6) were increased compared to the control group (4.7±4.5, 1.9±12). Correlation analysis: TLR-4 and MMP-9/TIMP-1 were positively correlated with the inflammations (r=0.18, P<0.01), WA% (r=0.68, P<0.01), and WT% (r=0.73, P<0.01), as well as positively correlated with the expression of PCNA (r=0.44, P<0.01); the upregulation of TLR-4 was positively correlated with the expressions of MMP-9 and TIMP-1. CONCLUSIONS: The upregulation of TLR-4 in the pulmonary arterial smooth muscle cells of COPD patients could promote the inflammations and the MMP-9 expression, thus causing abnormal degradation of extracellular matrix, so it played an important role in the process of PVR.

RESUMO OBJETIVO: Este estudo tem como objetivo investigar as expressões de TOLL-like receptor 4 (TLR-4) e metaloproteinase 9 da matriz (MMP-9)/inibidor de tecido da metaloproteinase 1 (TIMP-1) em vasos sanguíneos pulmonares com doença pulmonar obstrutiva crônica (DPOC) e suas relações com o remodelamento vascular pulmonar (PVR). MÉTODOS: Sessenta tecidos paratumorais foram divididos em grupo COPD e o grupo controle (n = 30). Foram comparadas as inflamações, área da parede da artéria pulmonar/área da artéria total (WA%) e espessura da parede/diâmetro externo vascular (WT%). As expressões de TLR-4, MMP-9/TIMP-1 e PCNA em células de músculo liso vascular pulmonar foram detectadas, e suas relações com PVR foram então analisadas. RESULTADOS: As inflamações (1,6 ± 0,8), WA% (44,0 ± 6,4) e WT% (27,3 ± 3,3) no grupo COPD foram maiores que no grupo controle (0,3 ± 0,5; 26,1 ± 2,8; 15,6 ± 1,8). E as expressões de TLR-4 (31,4 ± 14,7) e MMP-9/TIMP-1 (2,2 ± 2,6) foram aumentadas em relação ao grupo controle (4,7 ± 4,5, 1,9 ± 1,2). Na análise de correlação, TLR-4 e MMP-9/TIMP-1 foram positivamente correlacionadas com as inflamações (r = 0,18; P <0,01), WA% (r = 0,68; P <0,01) e WT% (r = 0,73; P <0,01), bem como correlacionadas positivamente com a expressão de PCNA (r = 0,44; P <0,01). A elevação da TLR-4 foi correlacionada positivamente com as expressões de MMP-9 e TIMP-1. CONCLUSÕES: A regulação positiva do TLR-4 nas células do músculo liso arterial pulmonar de pacientes com DPOC poderia promover as inflamações e a expressão de MMP-9, causando assim uma degradação anormal da matriz extracelular, por isso desempenhou um papel importante no processo de PVR.

Inhibition of mitochondrial fission prevents hypoxia-induced metabolic shift and cellular proliferation of pulmonary arterial smooth muscle cells.

Chronic hypoxia exacerbates proliferation of pulmonary arterial smooth muscle cells (PASMC), thereby reducing the lumen of pulmonary arteries. This leads to poor blood oxygenation and cardiac work overload, which are the basis of diseases such as pulmonary artery hypertension (PAH). Recent studies revealed an emerging role of mitochondria in PAH pathogenesis, as key regulators of cell survival and metabolism. In this work, we assessed whether hypoxia-induced mitochondrial fragmentation contributes to the alterations of both PASMC death and proliferation. In previous work in cardiac myocytes, we showed that trimetazidine (TMZ), a partial inhibitor of lipid oxidation, stimulates mitochondrial fusion and preserves mitochondrial function. Thus, here we evaluated whether TMZ-induced mitochondrial fusion can prevent human PASMC proliferation in an in vitro hypoxic model. Using confocal fluorescence microscopy, we showed that prolonged hypoxia (48h) induces mitochondrial fragmentation along with higher levels of the mitochondrial fission protein DRP1. Concomitantly, both mitochondrial potential and respiratory rates decreased, indicative of mitochondrial dysfunction. In accordance with a metabolic shift towards non-mitochondrial ATP generation, mRNA levels of glycolytic markers HK2, PFKFB2 and GLUT1 increased during hypoxia. Incubation of PASMC with TMZ, prior to hypoxia, prevented all these changes and precluded the increase in PASMC proliferation. These findings were also observed using Mdivi-1 (a pharmacological DRP1 inhibitor) or a dominant negative DRP1 K38A as pre-treatments. Altogether, our data indicate that TMZ exerts a protective role against hypoxia-induced PASMC proliferation, by preserving mitochondrial function, thus highlighting DRP1-dependent morphology as a novel therapeutic approach for diseases such as PAH.

Roles of the ERK1/2 and PI3K/PKB signaling pathways in regulating the expression of extracellular matrix genes in rat pulmonary artery smooth muscle cells.

PURPOSE:: To investigate the mechanisms by which PD98059 and LY294002 interfere with the abnormal deposition of extracellular matrix regulated by connective tissue growth factor (CTGF) of rat pulmonary artery smooth muscle cells (PASMCs). METHODS:: Rat PASMCs were cultured and separated into a control group. Real-time fluorescence quantitative PCR was performed to detect the expression of collagen III and fibronectin mRNA. Immunohistochemistry and western blot analyses were performed to detect the expression of collagen III protein. RESULTS:: The expression of collagen III and fibronectin mRNA was greater in PASMCs stimulated with CTGF for 48 h, than in the control group. After 72h of stimulation, the expression of collagen III protein in the PASMCs was greater than in the control. The equivalent gene and protein expression of the CPL group were much more significant. CONCLUSIONS:: CTGF can stimulate the gene expression of collagen III and fibronectin in PASMCs, which may be one of the factors that promote pulmonary vascular remodeling (PVR) under the conditions of pulmonary arterial hypertension (PAH). PD98059 and LY294002 can inhibit the ERK1/2 and PI3K/PKB signaling pathways, respectively, thus interfering with the biological effects of CTGF. This may be a new way to reduce PAH-PVR.