Plasmid-based short hairpin RNA against connective tissue growth factor attenuated monocrotaline-induced pulmonary vascular remodeling in rats

Hypoxia-induced long non-coding RNA plasmacytoma variant translocation 1 upregulation aggravates pulmonary arterial smooth muscle cell proliferation by regulating autophagy via miR-186/Srf/Ctgf and miR-26b/Ctgf signaling pathways

BACKGROUND

The lncRNA PVT1 reportedly functions as a competing endogenous RNA (ceRNA) of miR-186 and miR-26b in different tissue types. In this study, we investigated the possible involvement of the miR-186/Srf/Ctgf and miR-26b/Ctgf signaling pathways in the pathogenesis of hypoxia-induced PAH.

METHODS

Expression of PVT1, miR-186, miR-26b, and Srf and Ctgf mRNAs were evaluated by real-time polymerase chain reaction. Protein expression of SRF, CTGF, LC3B-I, LC3B-II, and Beclin-I was evaluated using western blotting. The regulatory relationship between the lncRNA, miRNAs, and target mRNAs was explored using luciferase assays. Immunohistochemistry was used to evaluate the expression of SRF and CTGF in situ. MTT assay was performed to assess the proliferation of PASMCs.

RESULTS

Exposure to hypoxia markedly altered the expression of PVT1, Srf, Ctgf, miR-186, and miR-26b in a rat model. MiR-186 binding sites in the sequences of Srf mRNA and PVT1 were confirmed by luciferase assays, indicating that miR-186 may interact with both PVT1 and Srf mRNA. Additionally, miR-26b binding sites were identified in the sequences of Ctgf mRNA and PVT1, suggesting that miR-26b may interact with both PVT1 and Ctgf mRNA. In line with this, we found that overexpression of PVT1 reduced expression of miR-26b and miR-186 but activated expression of Srf, Ctgf, LC3B-II, and Beclin-I.

CONCLUSIONS

Upregulation of PVT1 by exposure to hypoxia promoted the expression of CTGF, leading to deregulation of autophagy and abnormal proliferation of PASMCs. Dysregulation of the miR-186/Srf/Ctgf and miR-26b/Ctgf signaling pathways may be involved in the pathogenesis of hypoxia-induced PASMCs.

Effect of Methylation Status of lncRNA-MALAT1 and MicroRNA-146a on Pulmonary Function and Expression Level of COX2 in Patients With Chronic Obstructive Pulmonary Disease

This study aimed to investigate the role of methylation of MALAT1 and miR-146a in the pathogenesis of chronic obstructive pulmonary disease (COPD). COPD patients were grouped according to their methylation status of MALAT1 and miR-146a promoters, and we found that forced vital capacity, volume that has been exhaled at the end of the first second of forced expiration, and diffusion capacity for carbon monoxide were the highest in the MALAT1 HYPO + miR-146a HYPER group and lowest in the MALAT1 HYPER + miR-146a HYPO group, and COPD patients with hypermethylated MALAT1 showed lower expression of MALAT1 than that in the COPD patients with hypomethylated MALAT1. Meanwhile, miR-146a was the most significantly upregulated in the MALAT1 HYPER + miR-146a HYPO group and the most significantly downregulated in the MALAT1 HYPO + miR-146a HYPER group. Both prostaglandin E₁ and cyclooxygenase 2 (COX2) expression were the highest in the MALAT1 HYPO + miR-146a HYPER group and the lowest in the MALAT1 HYPER + miR-146a HYPO group. In conclusion, our results established a MALAT1/miR-146a/COX2 signaling axis. The overexpression of MALAT1 could increase the expression of COX2 by inhibiting the expression of miR-146a, thus affecting the pulmonary function of COPD patients.

Estrogen administration reduces the risk of pulmonary arterial hypertension by modulating the miR-133a signaling pathways in rats

We aimed to investigate how estrogen (ES) is implicated in the pathogenesis of pulmonary arterial hypertension (PAH) potentially by reducing the extent of vascular remodeling in females. HE assay, Western Blot, IHC, and real-time PCR were carried out to observe the role of ES in regulating miR-133a expression and the levels of MYOSLID, SRF, CTGF, and vascular remodeling in rats. In addition, MTT assay and flow cytometry were utilized to observe how ES affects cell proliferation and cell cycle in PAH. Moreover, luciferase assays were carried out to clarity the regulatory relationship between miR-133a and its downstream targets. ES administration relieved the deregulation of miR-133a, MYOSLID, SRF, and CTGF in PAH rats. In addition, ES also reduced the thickening of blood vessels in PAH rats. ES could activate miR-133a promoter and arrest the cells in the G0/G1 cycle, thus dose-dependently suppressing the proliferation of cells. In addition, the presence of ES, MYOSLID siRNA, or miR-133a precursor all altered the expression of MYOSLID, SP1, SRF, and CTGF, thus establishing a molecular signaling pathway among these factors. Furthermore, miR-133a could bind to SP1, MYOSLID, SRF, and CTGF to reduce their expression. Moreover, SRF was proved to function as an activator of miR-133a promoter. Two feedback loops were established in this study: a negative feedback loop between SRF and miR-133a, and a positive loop among miR-133a/SRF/MLK1/MYOSLID. ES treatment upregulates miR-133a expression and reduces the incidence of PAH and vascular remodeling.

Circular RNA hsa_circ_0016070 Is Associated with Pulmonary Arterial Hypertension by Promoting PASMC Proliferation

Noncoding RNAs play an important role in the pathogenesis of pulmonary arterial hypertension (PAH). In this study, we investigated the roles of hsa_circ_0016070, miR-942, and CCND1 in PAH. circRNA microarray was used to search circRNAs involved in PAH, whereas real-time PCR and western blot analysis were performed to detect miR-942 and CCND1 expression in different groups. In addition, the effect of miR-942 on CCND1 expression, as well as the effect of hsa_circ_0016070 on the expression of miR-942 and CCND1, was also studied using real-time PCR and western blot analysis. Moreover, MTT assay and flow cytometry were used to detect the effect of hsa _circ_0016070 on cell proliferation and cell cycle. According to the results of circRNA microarray analysis, hsa _circ_0016070 was identified to be associated with the risk of PAH in chronic obstructive pulmonary disease (COPD) patients. The miR-942 level in the COPD(+) PAH(+) group was much lower than that in the COPD(+) PAH(−) group, while the CCND1 level in the COPD(+) PAH(+) group was much higher. CCND1 was identified as a candidate target gene of miR-942, and the luciferase assay showed that the luciferase activity of wild-type CCND1 3′ UTR was inhibited by miR-942 mimics. In addition, hsa _circ_0016070 reduced miR-942 expression and enhanced CCND1 expression. Furthermore, hsa _circ_0016070 evidently increased cell viability and decreased the number of cells arrested in the G1/G0 phase. In summary, the results of this study suggested that hsa_circ_0016070 was associated with vascular remodeling in PAH by promoting the proliferation of pulmonary artery smooth muscle cells (PASMCs) via the miR-942/CCND1. Accordingly, has_circ_0016070 might be used as a novel biomarker in the diagnosis and treatment of PAH.

Identifying Involvement of H19-miR-675-3p-IGF1R and H19-miR-200a-PDCD4 in Treating Pulmonary Hypertension with Melatonin

Non-coding RNAs play an important role in the pathogenesis of pulmonary arterial hypertension (PAH). The aim of this study was to characterize the therapeutic role of melatonin as well as the underlying molecular mechanism (its effects on the expression of H19 and its downstream signaling pathways) in the treatment of PAH. Real-time PCR and western blot analysis were performed to evaluate the expression of H19, miR-200a, miR-675, insulin-like growth factor-1 receptor (IGF1R), and programmed cell death 4 (PDCD4). The value of systolic pulmonary artery pressure (SPAP) and the ratio of medial thickening in the monocrotaline (MCT) group were increased, whereas the melatonin treatment could decrease these values to some extent. The weights of RV (right ventricle), LV (left ventricle) + IVS (interventricular septal), and RV/(LV + IVS) in the MCT group were much higher than those in the MCT + melatonin and control groups. In addition, the expression of H19, miR-675, IGF1R mRNA, and IGF1R protein in the MCT group was the highest, whereas their expression in the control group was the lowest. The expression of miR-200, PDCD4 mRNA, and PDCD4 protein in the MCT group was the lowest, whereas their expression in the control group was the highest. Furthermore, H19 directly suppressed the expression of miR-200a, whereas miR-675-3p and miR-200a directly inhibited the expression of IGF1R and PDCD4, respectively. Finally, melatonin treatment inhibited cell proliferation; upregulated the expression of H19, miR-675-3p, and PDCD4; and downregulated the expression of miR-200a and IGF1R. This study demonstrated the role of H19-miR-675-3p-IGF1R- and H19-miR-200a-PDCD4-signaling pathways in the melatonin treatment of PAH.

Inhibition of Shp2 ameliorates monocrotaline-induced pulmonary arterial hypertension in rats

Background

Src homology 2 containing protein tyrosine phosphatase (PTP) 2 (Shp2) is a typical tyrosine phosphatase interacting with receptor tyrosine kinase to regulate multiple signaling pathways in diverse pathological processes. Here, we will investigate the effect of Shp2 inhibition on pulmonary arterial hypertension (PAH) in a rat model and its potential cellular and molecular mechanisms underlying.

Methods

Monocrotaline (MCT)-induced PAH rat model was used in this study. Phps-1, a highly selective inhibitor for Shp2, was administered from 21 days to 35 days after MCT single-injection. Microcatheter method was applied to detected hemodynamic parameters. Histological methods were used to determine PVR changes in PAH rats. Moreover, cultured pulmonary artery smooth muscle cells (PASMCs) treated by platelet-derived growth factor (PDGF) with or without Phps-1 was used to investigate the potential cellular and molecular mechanisms underlying in vitro.

Results

Inhibition of Shp2 significantly attenuated MCT-induced increases of mean pulmonary arterial pressure (mPAP), right ventricular systolic pressure (RVSP) and right ventricular hypertrophy (RVH) in rats. Shp2 inhibition effectively decreased thickening of pulmonary artery media and cardiomyocyte hypertrophy as well as perivascular and myocardial fibrosis in MCT-treated rats. Moreover, Shp2 inhibition ameliorated muscularization of pulmonary arterioles in MCT-induced PAH rats. Shp2 inhibition significantly reduced platelet-derived growth factor (PDGF)-triggered proliferation and migration of human pulmonary artery smooth muscle cells (PASMCs), which might be attributed to the inactivations of Akt and Stat3 pathways.

Conclusions

Shp2 contributes to the development of PAH in rats, which might be a potential target for the treatment of PAH.

Combined Effects of PVT1 and MiR-146a Single Nucleotide Polymorphism on the Lung Function of Smokers with Chronic Obstructive Pulmonary Disease

Non-coding RNAs play an important role in the pathogenesis of chronic obstructive pulmonary disease (COPD). This study was performed to investigate the role of PVT1 and miR-146a single nucleotide polymorphisms (SNPs) in the lung function of COPD smokers. Real-time PCR and Western blot analyses were performed to measure the expression of miR-146 and PVT1 SNPs and determine the effect of these SNPs on the pathogenesis of COPD. A total of 100 COPD smokers were enrolled in this study and divided into four groups as follows: Rs2910164CC/GC + Rs13281615GG; Rs2910164CC/GC + Rs13281615GA/AA; Rs2910164GG + Rs13281615GG; and Rs2910164GG + Rs13281615GA/AA. No obvious differences in terms of age, sex, and body height and weight were found among the four groups. However, the Rs2910164GG + Rs13281615GA/AA was associated with the highest stage of the Global Initiative for Chronic Obstructive Lung Disease and the highest values of the forced vital capacity, forced expiratory volume, and diffusing capacity of carbon monoxide, while the lowest values of these parameters were observed in the Rs2910164CC/GC + Rs13281615GG group. In addition, the highest and lowest COX2 levels were observed in the Rs2910164GG + Rs13281615GA/AA and Rs2910164CC/GC + Rs13281615GG groups, respectively. PVT1 directly and negatively regulated the miR-146a expression, which in turn directly and negatively regulated COX2 expression. Thus, the combined actions of SNP in PVT1 Rs13281615 and miR-146a Rs2910164 affected the lung function in COPD smokers.

Microrna-26b attenuates monocrotaline-induced pulmonary vascular remodeling via targeting connective tissue growth factor (CTGF) and cyclin D1 (CCND1)

MicroRNAs are involved in the control of cell growth, and deregulated pulmonary artery smooth muscle cell proliferation plays an essential role in the development of pulmonary hypertension. The objective of this study was to identify differentially expressed microRNA(s) and explore its therapeutic role in treatment of the disease. MicroRNA expression profile analysis showed microRNA-26b was differentially expressed in pulmonary artery smooth muscle cells harvested from monocrotaline-treated rats, and we validated microRNA-26b targets, in vitro and in vivo, CTGF and CCND1, both of which have been shown, in our previous work, to be involved in the pathogenesis of pulmonary hypertension. In vivo experiments demonstrated monocrotaline-induced pulmonary artery remodeling could be almost completely abolished by administration of microRNA-26b, while CTGF or CCND1 shRNA significantly, but only partially, attenuated the remodeling by silencing the designed target. Additionally, exogenous expression of the microRNA-26b substantially downregulated CTGF and CCND1 in human pulmonary artery smooth muscle cells. MicroRNA-26b might be a potent therapeutic tool to treat pulmonary hypertension.

Hypoxia-induced microRNA-26b inhibition contributes to hypoxic pulmonary hypertension via CTGF

The objective of this study was to explore the role of miRNAs in the control of HPH as well as molecular mechanism underlying. Computational analysis and luciferase assay were carried out to search the target gene of miR-26b. Luciferase assay, RT-PCR and western-blot analysis was performed to test interaction among hypoxia, miR-26b, SRF and CTGF. MiR-26b was significantly downregulated; meanwhile, CTGF and SRF were significantly upregulated in HPH rat model. Using computational analysis, CTGF was found to be a virtual target gene of miR-26b, and only cell transfected with vectors containing wild-type CTGF 3'UTR and miR-26b showed a lower luciferase activity than scramble control. Hypoxia significantly inhibited miR-26b promoter, and promoted SRF promoter. Meanwhile, hypoxia had no effect on CTGF promoter. In addition, SRF promoted the promoter of CTGF. MiR-26b was significantly downregulated; meanwhile, CTGF and SRF were upregulated in PASMCs exposed to hypoxia. In addition, miR-26b and SRF siRNA, but not CTGF siRNA, significantly inhibited SRF expression. Meanwhile, miR-26b, SRF siRNA, and CTGF siRNA significantly inhibited CTGF expression in hypoxia-treated cell. PASMCs treated with hypoxia showed higher cell viability and higher percentage cells in S phase than the control, which could be reversed by miR-26b, SRF siRNA, and CTGF siRNA transfection. These findings suggested that hypoxia induced miR-26b inhibition and SRF and CTGF upregulation in HPH rat model. CTGF mediated hypoxia-induced regulation of miR-26b and SRF in proliferation of PASMCs, which indicated that hypoxia-induced miR-26b inhibition contributed to the pathogenesis of HPH via CTGF.

Genetic Modification of the Lung Directed Toward Treatment of Human Disease

Genetic modification therapy is a promising therapeutic strategy for many diseases of the lung intractable to other treatments. Lung gene therapy has been the subject of numerous preclinical animal experiments and human clinical trials, for targets including genetic diseases such as cystic fibrosis and α1-antitrypsin deficiency, complex disorders such as asthma, allergy, and lung cancer, infections such as respiratory syncytial virus (RSV) and Pseudomonas, as well as pulmonary arterial hypertension, transplant rejection, and lung injury. A variety of viral and non-viral vectors have been employed to overcome the many physical barriers to gene transfer imposed by lung anatomy and natural defenses. Beyond the treatment of lung diseases, the lung has the potential to be used as a metabolic factory for generating proteins for delivery to the circulation for treatment of systemic diseases. Although much has been learned through a myriad of experiments about the development of genetic modification of the lung, more work is still needed to improve the delivery vehicles and to overcome challenges such as entry barriers, persistent expression, specific cell targeting, and circumventing host anti-vector responses.

A Time- and Compartment-Specific Activation of Lung Macrophages in Hypoxic Pulmonary Hypertension

Studies in various animal models suggest an important role for pulmonary macrophages in the pathogenesis of pulmonary hypertension (PH). Yet, the molecular mechanisms characterizing the functional macrophage phenotype relative to time and pulmonary localization and compartmentalization remain largely unknown. In this study, we used a hypoxic murine model of PH in combination with FACS to quantify and isolate lung macrophages from two compartments over time and characterize their programing via RNA sequencing approaches. In response to hypoxia, we found an early increase in macrophage number that was restricted to the interstitial/perivascular compartment, without recruitment of macrophages to the alveolar compartment or changes in the number of resident alveolar macrophages. Principal component analysis demonstrated significant differences in overall gene expression between alveolar and interstitial macrophages (IMs) at baseline and after 4 and 14 d hypoxic exposure. Alveolar macrophages at both day 4 and 14 and IMs at day 4 shared a conserved hypoxia program characterized by mitochondrial dysfunction, proinflammatory gene activation, and mTORC1 signaling, whereas IMs at day 14 demonstrated a unique anti-inflammatory/proreparative programming state. We conclude that the pathogenesis of vascular remodeling in hypoxic PH involves an early compartment-independent activation of lung macrophages toward a conserved hypoxia program, with the development of compartment-specific programs later in the course of the disease. Thus, harnessing time- and compartment-specific differences in lung macrophage polarization needs to be considered in the therapeutic targeting of macrophages in hypoxic PH and potentially other inflammatory lung diseases.

Upregulation of SRF Is Associated With Hypoxic Pulmonary Hypertension by Promoting Viability of Smooth Muscle Cells via Increasing Expression of Bcl-2

The aim of study was to investigate the involvement of hypoxia-induced upregulation of serum response factor (SRF) and its downstream effector, B cell leukemia-2 (Bcl-2), in hypoxia-induced pulmonary hypertension (PH). Immunohistochemistry analysis and western blot analysis were used to detect the levels of SRF and Bcl-2 in rats exposed to hypoxia. Furthermore, the regulatory relationship between SRF and Bcl-2 was investigated in PASMCs using real-time PCR and western-blot analysis. We found that mPAP (mean pulmonary arterial pressure) and WA (the ratio of vascular wall area to external diameter) were increased after exposure to hypoxia, while LA (the ratio of vascular lumen area to total area) decreased after exposure to hypoxia. The immunohistochemistry analysis displayed a substantial increase in SRF and Bcl-2 in pulmonary arterial walls after 14 days of hypoxia. And the western blotting showed that SRF and Bcl-2 protein levels were much higher after 7 days of hypoxia and then remained at a high level. And then the levels of SRF and Bcl-2 in pulmonary artery smooth muscle cells (PASMCs) exposed to hypoxia were substantially suppressed following introduction of SRF siRNA, and the level of Bcl-2 was remarkably inhibited by Bcl-2 siRNA, while Bcl-2 siRNA had no effect on SRF level. Finally, SRF siRNA, and Bcl-2 siRNA significantly reduced viability of PASMCs exposed to hypoxia, and enhanced apoptosis of PASMCs exposed to hypoxia. These data validated that SRF responded to hypoxia, which subsequently was involved in pulmonary hypertension by abnormally promoting viability of PASMCs via modulating expression of Bcl-2. J. Cell. Biochem. 118: 2731-2738, 2017. © 2017 Wiley Periodicals, Inc.

Lung-specific RNA interference of coupling factor 6, a novel peptide, attenuates pulmonary arterial hypertension in rats

Background

Pulmonary arterial hypertension (PAH) is a progressive and life-threatening disease associated with high morbidity and mortality rates. However, the exact regulatory mechanism of PAH is unknown. Although coupling factor 6 (CF6) is known to function as a repressor, its role in PAH has not been explored. Here, we investigated the involvement of endogenous CF6 in the development of PAH.

Methods

PAH was induced with monocrotaline (MCT), as demonstrated by significant increases in pulmonary artery pressure and vessel wall thickness. The adeno-associated virus (AAV) carrying CF6 short hairpin RNA (shRNA) or control vector (2×10¹⁰ gp) was intratracheally transfected into the lungs of rats 2 weeks before or after MCT injection.

Results

A 2-6-fold increase in CF6 was observed in the lungs and circulation of the MCT-injected rats as confirmed by qRT-PCR and ELISA. Immunohistochemistry analysis revealed a small quantity of CF6 localized to endothelial cells (ECs) under physiological conditions spread to surrounding tissues in a paracrine manner in PAH lungs. Notably, CF6 shRNA effectively inhibited CF6 expression, abolished lung macrophage infiltration, reversed endothelial dysfunction and vascular remodeling, and ameliorated the severity of pulmonary hypertension and right ventricular dysfunction at 4 weeks both as a pretreatment and rescue intervention. In addition, the circulating and lung levels of 6-keto-PGF1a, a stable metabolite of prostacyclin, were reversed by CF6 inhibition, suggesting that the effect of CF6 inhibition may partly be mediated through prostacyclin.

Conclusions

CF6 contributes to the pathogenesis of PAH, probably in association with downregulation of prostacyclin. The blockage of CF6 might be applied as a novel therapeutic approach for PAH and PA remodeling.

Electronic supplementary material

The online version of this article (doi:10.1186/s12931-016-0409-5) contains supplementary material, which is available to authorized users.

NADPH oxidase 4 contributes to connective tissue growth factor expression through Smad3-dependent signaling pathway

Transforming growth factor-β (TGF-β)/Smad signaling has been implicated in connective tissue growth factor (CTGF) expression in vascular smooth muscle cells (VSMC). Reactive oxygen species (ROS) are involved in activation of TGF-β/Smad signaling. However, detailed mechanisms underlying the process remain unclear. In present study, we demonstrated TGF-β1 strongly induced CTGF expression, Smad3 activation, NADPH oxidase 4 (Nox4) expression and increased ROS production in primary rat VSMC in vitro. NADPH oxidases inhibitor diphenylene iodonium (DPI) eliminated TGF-β1-induced CTGF expression and ROS generation. In addition, small-interfering RNA (siRNA) silencing of Smad3 or Nox4 significantly suppressed TGF-β1-mediated CTGF expression in VSMC. Furthermore, Nox4 silencing or inhibition eliminated TGF-β1-induced Smad3 activation and interaction between Nox4 and Smad3. In vivo studies further identified a positive correlation of Nox4 levels with Smad3 activation and CTGF expression in atherosclerotic arteries of patients and animal models. These data established that a novel mechanistic link of Nox4-dependent activation of Smad3 to increased TGF-β1-induced CTGF in the process of vascular remodeling, which suggested a new potential pathway for therapeutic interventions.