Role of ROS/Kv/HIF Axis in the Development of Hypoxia-Induced Pulmonary Hypertension

Gene Expression Trajectories from Normal Nonsmokers to COPD Smokers and Disease Progression Discriminant Modeling in Response to Cigarette Smoking

Background

Cigarette smoking (CS) is considered to the predominant risk factor contributing to the etiopathogenesis of chronic obstructive pulmonary disease (COPD); meanwhile, genetic predisposition likely plays a role in determining disease susceptibility.

Objectives

We aimed to investigate gene expression trajectories from normal nonsmokers to COPD smokers and disease progression discriminant modeling in response to cigarette smoking.

Methods

Small airway epithelial samples of human with different smoking status using fiberoptic bronchoscopy and corresponding rat lung tissues following 0, 3, and 6 months of CS exposure were obtained. The expression of the significant overlapping genes between human and rats was confirmed in 16HBE cells, rat lung tissues, and human peripheral PBMC using qRT-PCR. Binary logistic regression analysis was carried out to establish discrimination models.

Results

The integrated bioinformatic analysis of 8 human GEO datasets (293 individuals) and 9 rat transcriptome databases revealed 13 overlapping genes between humans and rats in response to smoking exposure during COPD progression. Of these, 5 genes (AKR1C3/Akr1c3, ERP27/Erp27, AHRR/Ahrr, KCNMB2/Kcnmb2, and MRC1/Mrc1) were consistently identified in both the human and rat and validated by qRT-PCR. Among them, ERP27/Erp27, KCNMB2/Kcnmb2, and MRC1/Mrc1 were newly identified. On the basis of the overlapping gene panel, discriminant models were established with the receiver operating characteristic curve (AUC) of 0.98 (AKR1C3/Akr1c3 + ERP27/Erp27) and 0.99 (AHRR/Ahrr + KCNMB2/Kcnmb2) in differentiating progressive COPD from normal nonsmokers. In addition, we also found that DEG obtained from each expression profile dataset was better than combined analysis as more genes could be identified.

Conclusion

This study identified 5 DEG candidates of COPD progression in response to smoking and developed effective and convenient discriminant models that can accurately predict the disease progression.

AMPK and the Challenge of Treating Hypoxic Pulmonary Hypertension

Hypoxic pulmonary hypertension (HPH) is characterized by sustained elevation of pulmonary artery pressure produced by vasoconstriction and hyperproliferative remodeling of the pulmonary artery and subsequent right ventricular hypertrophy (RVH). The search for therapeutic targets for cardiovascular pathophysiology has extended in many directions. However, studies focused on mitigating high-altitude pulmonary hypertension (HAPH) have been rare. Because AMP-activated protein kinase (AMPK) is involved in cardiovascular and metabolic pathology, AMPK is often studied as a potential therapeutic target. AMPK is best characterized as a sensor of cellular energy that can also restore cellular metabolic homeostasis. However, AMPK has been implicated in other pathways with vasculoprotective effects. Notably, cellular metabolic stress increases the intracellular ADP/ATP or AMP/ATP ratio, and AMPK activation restores ATP levels by activating energy-producing catabolic pathways and inhibiting energy-consuming anabolic pathways, such as cell growth and proliferation pathways, promoting cardiovascular protection. Thus, AMPK activation plays an important role in antiproliferative, antihypertrophic and antioxidant pathways in the pulmonary artery in HPH. However, AMPK plays contradictory roles in promoting HPH development. This review describes the main findings related to AMPK participation in HPH and its potential as a therapeutic target. It also extrapolates known AMPK functions to discuss the less-studied HAPH context.

Protection function of 18β-glycyrrhetinic acid on rats with high-altitude pulmonary hypertension based on 1H NMR metabonomics technology

18β-Glycyrrhetinic acid (GA) is the triterpenoid aglycone component of glycyrrhizic acid, a natural product of traditional Chinese medicine, and has been proven to possess a variety of pharmacological effects. The protection function and the mechanism of GA on rats with high-altitude pulmonary hypertension (HAPH) are studied using proton nuclear magnetic resonance (1H NMR) metabonomics technology and biochemical analysis. An HAPH model is established, and 60 male rats are randomly divided into the following groups: Control(normal saline, 0.4 mL/100 g), model (normal saline, 0.4 mL/100 g), Nifedipine (nifedipine, 2.7 mg/kg), and high-, medium-, and low-dose GA groups (100, 50, and 25 mg/kg GA designated as GA.H, GA.M, and GA.L, respectively). Serum biochemical indicators of rats in each group are measured, and pathological changes in the pulmonary artery are observed. 1H NMR metabonomics technology is used for serum analysis. Results show that GA can significantly reduce pulmonary arterial pressure and malondialdehyde levels and increase the glutathione peroxidase and superoxide dismutase activities in HAPH rats. Pathological results show that GA can alleviate pulmonary artery injuries of HAPH rats. Metabolomics analytical findings show that GA can alleviate the metabolic disorder of HAPH rats through anti-oxidation and anti-inflammatory effects, improve their bodies' ability to resist hypoxia, and restore various metabolic pathways (energy metabolism, amino acid metabolism, and lipid metabolism). GA has potential therapeutic effects on HAPH rats, but its target needs to be further studied.

The newborn sheep translational model for pulmonary arterial hypertension of the neonate at high altitude

Chronic hypoxia during gestation induces greater occurrence of perinatal complications such as intrauterine growth restriction, fetal hypoxia, newborn asphyxia, and respiratory distress, among others. This condition may also cause a failure in the transition of the fetal to neonatal circulation, inducing pulmonary arterial hypertension of the neonate (PAHN), a syndrome that involves pulmonary vascular dysfunction, increased vasoconstrictor tone and pathological remodeling. As this syndrome has a relatively low prevalence in lowlands (~7 per 1000 live births) and very little is known about its prevalence and clinical evolution in highlands (above 2500 meters), our understanding is very limited. Therefore, studies on appropriate animal models have been crucial to comprehend the mechanisms underlying this pathology. Considering the strengths and weaknesses of any animal model of human disease is fundamental to achieve an effective and meaningful translation to clinical practice. The sheep model has been used to study the normal and abnormal cardiovascular development of the fetus and the neonate for almost a century. The aim of this review is to highlight the advances in our knowledge on the programming of cardiopulmonary function with the use of high-altitude newborn sheep as a translational model of PAHN.

WITHDRAWN: Anti-inflammatory role and mechanism of microRNA-92b-3p in the progression of hypoxic pulmonary hypertension

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MicroRNA‑153 attenuates hypoxia‑induced excessive proliferation and migration of pulmonary arterial smooth muscle cells by targeting ROCK1 and NFATc3

The aim of the present study was to explore the effect of microRNA (miR)‑153 on the proliferation and migration of pulmonary artery smooth muscle cells (PASMCs) in a hypoxic condition by targeting ρ‑associated, coiled‑coil‑containing protein kinase 1 (ROCK1) and nuclear factor of activated T cells cytoplasmic 3 (NFATc3). The right ventricular systolic pressure, right ventricular hypertrophy index, medial wall thickness and medial wall area were studied at different time‑points after rats were exposed to hypoxia. Western blot analysis was used to detect ROCK1 and NFATc3 protein levels. In addition, reverse transcription‑quantitative (RT‑q) PCR was performed to confirm the mRNA levels of miR‑153, ROCK1 and NFATc3 in human (H)PASMCs under hypoxic conditions. Transfected cells were then used to evaluate the effect of miR‑153 on cell proliferation and migration abilities. The association between miR‑153 and ROCK1 or NFATc3 was identified through double luciferase assays. Hypoxia induced pulmonary vascular remodeling and pulmonary arterial hypertension, which resulted from the abnormal proliferation of HPASMCs. ROCK1 and NFATc3 were the target genes of miR‑153 and miR‑153 mimic inhibited the protein expressions of ROCK1 and NFATc3 in HPASMCs and further inhibited cell proliferation and migration under hypoxic conditions. By contrast, the miR‑153 inhibitor promoted the proliferation and migration of HPASMCs. miR‑153 regulated the proliferation and migration of HPASMCs under hypoxia by targeting ROCK1 and NFATc3.

H2S attenuates endoplasmic reticulum stress in hypoxia-induced pulmonary artery hypertension

Background: Previous studies have found that hydrogen sulfide (H₂S) has multiple functions such as anti-inflammatory, antioxidative in addition to biological effects among the various organs. Exaggerated proliferation and resistance to apoptosis of pulmonary artery smooth muscle cells (PASMCs) is a key component of vascular remodeling. We hypothesized that endogenous bioactive molecular known to suppress endoplasmic reticulum (ER) stress signaling, like H₂S, will inhibit the disruption of the ER-mitochondrial unit and prevent/reverse pulmonary arterial hypertension (PAH).

Methods and results: A hypoxic model was established with PASMCs to investigate the possible role of H₂S in PAH. Effects of H₂S on proliferation of PASMCs were evaluated by CCK-8 and EdU assay treated with or without GYY4137 (donor of H₂S). H₂S significantly inhibited hypoxia-induced increase in PASMCs proliferation in a dose-dependent manner. H₂S by intraperitoneal injection with rats both prevented and reversed chronic hypoxia-induced pulmonary hypertension in rats, decreasing pulmonary vascular resistance, pulmonary artery remodeling and right ventricular hypertrophy, and improving functional capacity without affecting systemic hemodynamic. Exogenous H₂S suppressed ER stress indexes in vivo and in vitro, decreased activating transcription factor 6 activation, and inhibited the hypoxia-induced decrease in mitochondrial calcium and mitochondrial function.

Conclusion: H₂S effectively inhibits hypoxia-induced increase in cell proliferation, migration, and oxidative stress in PASMCs, and NOX-4 might be the underlying mechanism of PAH. Attenuating ER stress with exogenous H₂S may be a novel therapeutic strategy in pulmonary hypertension with high translational potential.