TUG1 Regulates Pulmonary Arterial Smooth Muscle Cell Proliferation in Pulmonary Arterial Hypertension

Androgen receptor deficiency-induced TUG1 in suppressing ferroptosis to promote benign prostatic hyperplasia through the miR-188-3p/GPX4 signal pathway

Benign prostatic hyperplasia (BPH), characterized by the non-malignant enlargement of the prostate, exhibits a pronounced association with inflammation resulting from androgen receptor (AR) deficiency. Ferroptosis, a cell death mechanism triggered by iron-dependent lipid peroxidation and closely linked to inflammation, has yet to be fully understood in the context of BPH. Using RNA sequencing, we observed a significant elevation of taurine-upregulated gene 1 (TUG1) long noncoding RNA (lncRNA) in BPH tissues compared to normal prostate tissue. High levels of TUG1 exhibited a discernible correlation with both prostate volume and the extent of inflammatory infiltration in BPH patients. The suppression of TUG1 not only led to a reduction in prostate size but also ameliorated AR-deficiency-induced prostatic hyperplasia. Mechanistically, a decrease in AR in prostate luminal cells prompted macrophage aggregation and the release of IL-1β, subsequently fostering the transcription of TUG1 via MYC. Induced TUG1, through competitive binding with miR-188-3p, facilitated the expression of GPX4, thereby diminishing intracellular ROS levels and impeding ferroptosis in prostate luminal cells. Notably, the ferroptosis inducer JKE-1674 alleviated inflammation-induced prostatic hyperplasia in vivo. Together, these findings suggest that AR deficiency crucially inhibits ferroptosis, promoting BPH via the TUG1/miR-188-3p/GPX4 signaling axis, and making ferroptosis induction a promising therapeutic strategy for BPH patients with AR deficiency.

Long non-coding RNA TUG1 is downregulated in Friedreich's ataxia

Friedreich's ataxia is a neurodegenerative disorder caused by reduced frataxin levels. It leads to motor and sensory impairments and has a median life expectancy of around 35 years. As the most common inherited form of ataxia, Friedreich's ataxia lacks reliable, non-invasive biomarkers, prolonging and inflating the cost of clinical trials. This study proposes TUG1, a long non-coding RNA, as a promising blood-based biomarker for Friedreich's ataxia, which is known to regulate various cellular processes. In a previous study using a frataxin knockdown mouse model, we observed several hallmark Friedreich's ataxia symptoms. Building on this, we hypothesized that a dual-source approach-comparing the data from peripheral blood samples from Friedreich's ataxia patients with tissue samples from affected areas in Friedreich's ataxia knockdown mice, tissues usually unattainable from patients-would effectively identify robust biomarkers. A comprehensive reanalysis was conducted on gene expression data from 183 age- and sex-matched peripheral blood samples of Friedreich's ataxia patients, carriers and controls and 192 tissue data sets from Friedreich's ataxia knockdown mice. Blood and tissue samples underwent RNA isolation and quantitative reverse transcription polymerase chain reaction, and frataxin knockdown was confirmed through enzyme-linked immunosorbent assays. Tug1 RNA interaction was explored via RNA pull-down assays. Validation was performed in serum samples on an independent set of 45 controls and 45 Friedreich's ataxia patients and in blood samples from 66 heterozygous carriers and 72 Friedreich's ataxia patients. Tug1 and Slc40a1 emerged as potential blood-based biomarkers, confirmed in the Friedreich's ataxia knockdown mouse model (one-way ANOVA, P ≤ 0.05). Tug1 was consistently downregulated after Fxn knockdown and correlated strongly with Fxn levels (R 2 = 0.71 during depletion, R 2 = 0.74 during rescue). Slc40a1 showed a similar but tissue-specific pattern. Further validation of Tug1's downstream targets strengthened its biomarker candidacy. In additional human samples, TUG1 levels were significantly downregulated in both whole blood and serum of Friedreich's ataxia patients compared with controls (Wilcoxon signed-rank test, P < 0.05). Regression analyses revealed a negative correlation between TUG1 fold-change and disease onset (P < 0.0037) and positive correlations with disease duration and functional disability stage score (P < 0.04). This suggests that elevated TUG1 levels correlate with earlier onset and more severe cases. This study identifies TUG1 as a potential blood-based biomarker for Friedreich's ataxia, showing consistent expression variance in human and mouse tissues related to disease severity and key Friedreich's ataxia pathways. It correlates with frataxin levels, indicating its promise as an early, non-invasive marker. TUG1 holds potential for Friedreich's ataxia monitoring and therapeutic development, meriting additional research.

ANRIL, H19 and TUG1: a review about critical long non-coding RNAs in cardiovascular diseases

Cardiovascular diseases are the leading cause of death worldwide. They are non-transmissible diseases that affect the cardiovascular system and have different etiologies such as smoking, lipid disorders, diabetes, stress, sedentary lifestyle and genetic factors. To date, lncRNAs have been associated with increased susceptibility to the development of cardiovascular diseases such as hypertension, acute myocardial infarction, stroke, angina and heart failure. In this way, lncRNAs are becoming a very promising point for the prevention and diagnosis of cardiovascular diseases. Therefore, this review highlights the most important and recent discoveries about the mechanisms of action of the lncRNAs ANRIL, H19 and TUG1 and their clinical relevance in these pathologies. This may contribute to early detection of cardiovascular diseases in order to prevent the pathological phenotype from becoming established.

Restoration of miR-328a-5p function curtails hypoxic pulmonary hypertension through a mechanism involving PIN1/GSK3β/β-catenin axis

Recent evidence has highlighted the involvement of microRNAs (miRs) in hypoxic pulmonary hypertension (PH), which can be induced under hypoxic conditions. We intend to explore whether the miR-328a-5p/PIN1 axis affects hypoxic PH by regulating the GSK3β/β-catenin signaling pathway. The GEO database was retrieved to single out key miRs affecting hypoxic PH. It was observed that downregulation of miR-328a-5p occurred in hypoxia-induced PH samples. The binding affinity between miR-328a-5p to PIN1 was predicted by a bioinformatics tool and verified using a dual luciferase reporter gene assay. Rat primary pulmonary artery smooth muscle cells (PASMCs) were exposed to hypoxia for in vitro cell experiments. miR-328a-5p could target and downregulate PIN1 expression, leading to suppressed GSK3β/β-catenin activation. In addition, GSK3β/β-catenin inactivation curtailed hypoxia-induced vascular inflammatory responses and proliferation and migration in PASMCs in vitro. A hypoxic PH model was established in SD rats to observe the effects of miR-328a-5p on hemodynamic parameters and right heart remodeling. It was demonstrated in vivo that miR-328a-5p downregulated PIN1 expression to suppress GSK3β/β-catenin signaling, thereby reducing the vascular inflammatory response and alleviating disease progression in hypoxia-induced PH rats. The evidence provided by our study highlighted the involvement of miR-328a-5p in the translational suppression of PIN1 and the blockade of the GSK3β/β-catenin signaling pathway, resulting in attenuation of hypoxic PH progression.

Unraveling the epigenetic landscape of pulmonary arterial hypertension: implications for personalized medicine development

Pulmonary arterial hypertension (PAH) is a multifactorial disease associated with the remodeling of pulmonary blood vessels. If left unaddressed, PAH can lead to right heart failure and even death. Multiple biological processes, such as smooth muscle proliferation, endothelial dysfunction, inflammation, and resistance to apoptosis, are associated with PAH. Increasing evidence suggests that epigenetic factors play an important role in PAH by regulating the chromatin structure and altering the expression of critical genes. For example, aberrant DNA methylation and histone modifications such as histone acetylation and methylation have been observed in patients with PAH and are linked to vascular remodeling and pulmonary vascular dysfunction. In this review article, we provide a comprehensive overview of the role of key epigenetic targets in PAH pathogenesis, including DNA methyltransferase (DNMT), ten-eleven translocation enzymes (TET), switch-independent 3A (SIN3A), enhancer of zeste homolog 2 (EZH2), histone deacetylase (HDAC), and bromodomain-containing protein 4 (BRD4). Finally, we discuss the potential of multi-omics integration to better understand the molecular signature and profile of PAH patients and how this approach can help identify personalized treatment approaches.

Long non-coding RNAs: The growth controller of vascular smooth muscle cells in cardiovascular diseases

The active proliferation and migration of vascular smooth muscle cells supports the healing of vessel damage while their abnormal aggression or destitution contribute to the aberrant intima-medial structure and function in various cardiovascular diseases, so the understanding of the proliferation disorders of vascular smooth muscle cell and the related mechanism is the basis of effective intervention and control for cardiovascular diseases. Recently, long non-coding RNAs have stood out as upstream switchers for multiple proliferative signaling pathways and molecules, and many of them have been shown to conduce to the dysregulated proliferation and apoptosis of vascular smooth muscle cells under various pathogenic stimuli. This article discusses the long non-coding RNAs disclosed and linked to atherosclerosis, pulmonary hypertension, and aneurysms, and focuses upon their modulation of vascular smooth muscle cell population affecting three deadly cardiovascular diseases.

Long Non-Coding RNA TUG1 Attenuates Insulin Resistance in Mice with Gestational Diabetes Mellitus via Regulation of the MicroRNA-328-3p/SREBP-2/ERK Axis

BACKGROUND

Long non-coding RNAs (lncRNAs) have been illustrated to contribute to the development of gestational diabetes mellitus (GDM). In the present study, we aimed to elucidate how lncRNA taurine upregulated gene 1 (TUG1) influences insulin resistance (IR) in a high-fat diet (HFD)-induced mouse model of GDM.

METHODS

We initially developed a mouse model of HFD-induced GDM, from which islet tissues were collected for RNA and protein extraction. Interactions among lncRNA TUG1/microRNA (miR)-328-3p/sterol regulatory element binding protein 2 (SREBP-2) were assessed by dual-luciferase reporter assay. Fasting blood glucose (FBG), fasting insulin (FINS), homeostasis model assessment of insulin resistance (HOMA-IR), HOMA pancreatic β-cell function (HOMA-β), insulin sensitivity index for oral glucose tolerance tests (ISOGTT) and insulinogenic index (IGI) levels in mouse serum were measured through conducting gain- and loss-of-function experiments.

RESULTS

Abundant expression of miR-328 and deficient expression of lncRNA TUG1 and SREBP-2 were characterized in the islet tissues of mice with HFD-induced GDM. LncRNA TUG1 competitively bound to miR-328-3p, which specifically targeted SREBP-2. Either depletion of miR-328-3p or restoration of lncRNA TUG1 and SREBP-2 reduced the FBG, FINS, HOMA-β, and HOMA-IR levels while increasing ISOGTT and IGI levels, promoting the expression of the extracellular signal-regulated kinase (ERK) signaling pathway-related genes, and inhibiting apoptosis of islet cells in GDM mice. Upregulation miR-328-3p reversed the alleviative effects of SREBP-2 and lncRNA TUG1 on IR.

CONCLUSION

Our study provides evidence that the lncRNA TUG1 may prevent IR following GDM through competitively binding to miR-328-3p and promoting the SREBP-2-mediated ERK signaling pathway inactivation.

Supplementation with Tex261 provides a possible preventive treatment for hypoxic pulmonary artery hypertension

Objectives: Pulmonary artery hypertension (PAH) is a serious disease for which there is no effective treatment. Its pathogenesis is complex and has not yet been clarified. Tex261 is a protein-coding gene whose functional enrichment nodes include the transporter activity of COP II. However, the role of Tex261 in PAH remains unknown. Methods: Sugen5416/Hypoxic PAH models were established, and pulmonary arteries (PAs) were isolated for proteomic sequencing. The binding sites between Hif-1α and Tex261 were verified by dual-luciferase reporter gene assay. Cell proliferation was detected by MTS and EdU assays. For determination of the preventive and therapeutic effects of Tex261, intratracheal instillation of adeno-associated virus (AVV6) with Tex261 vectors was performed. Results: Tex261 was screened according to the proteomic sequencing data. Hif-1α inhibited Tex261 promoter activity under hypoxia. Decreased Tex261 expression promoted PASMC proliferation. Tex261 regulated Sec23 via the Ndrg1-mediated Akt pathway. Tex261 overexpression improved the pressure and vessel remodeling of PAs induced by Sugen5416/hypoxia. Conclusion: Hypoxia suppressed Tex261 expression through Hif-1α activation. The decreased Tex261 could promote Ndrg1 and depress Akt activity and then inhibit Sec23 activity, which leads to cell proliferation and vessel remodeling. Elevated Tex261 has some preventive and therapeutic effects on rats with PAH.

The Novel Regulatory Role of the lncRNA–miRNA–mRNA Axis in Chronic Inflammatory Airway Diseases

Chronic inflammatory airway diseases, characterized by airway inflammation and airway remodelling, are increasing as a cause of morbidity and mortality for all age groups and races across the world. The underlying molecular mechanisms involved in chronic inflammatory airway diseases have not been fully explored. MicroRNAs (miRNAs) and long noncoding RNAs (lncRNAs) have recently attracted much attention for their roles in the regulation of a variety of biological processes. A number of studies have confirmed that both lncRNAs and miRNAs can regulate the initiation and progression of chronic airway diseases by targeting mRNAs and regulating different cellular processes, such as proliferation, apoptosis, inflammation, migration, and epithelial–mesenchymal transition (EMT). Recently, accumulative evidence has shown that the novel regulatory mechanism underlying the interaction among lncRNAs, miRNAs and messenger RNAs (mRNAs) plays a critical role in the pathophysiological processes of chronic inflammatory airway diseases. In this review, we comprehensively summarized the regulatory roles of the lncRNA–miRNA–mRNA network in different cell types and their potential roles as biomarkers, indicators of comorbidities or therapeutic targets for chronic inflammatory airway diseases, particularly chronic obstructive pulmonary disease (COPD) and asthma.

The Landscape of Noncoding RNA in Pulmonary Hypertension

The transcriptome of pulmonary hypertension (PH) is complex and highly genetically heterogeneous, with noncoding RNA transcripts playing crucial roles. The majority of RNAs in the noncoding transcriptome are long noncoding RNAs (lncRNAs) with less circular RNAs (circRNAs), which are two characteristics gaining increasing attention in the forefront of RNA research field. These noncoding transcripts (especially lncRNAs and circRNAs) exert important regulatory functions in PH and emerge as potential disease biomarkers and therapeutic targets. Recent technological advancements have established great momentum for discovery and functional characterization of ncRNAs, which include broad transcriptome sequencing such as bulk RNA-sequence, single-cell and spatial transcriptomics, and RNA-protein/RNA interactions. In this review, we summarize the current research on the classification, biogenesis, and the biological functions and molecular mechanisms of these noncoding RNAs (ncRNAs) involved in the pulmonary vascular remodeling in PH. Furthermore, we highlight the utility and challenges of using these ncRNAs as biomarkers and therapeutics in PH.

LncRNA-GAS5/miR-382-3p axis inhibits pulmonary artery remodeling and promotes autophagy in chronic thromboembolic pulmonary hypertension

BACKGROUND

We have clarified the role of miR-382-3p in chronic thromboembolic pulmonary hypertension (CTEPH), but what is less clear lies in its upstream regulatory mechanism.

OBJECTIVE

To explore the regulation mechanism of GAS5/miR-382-3p axis on CTEPH.

METHODS

In vitro, we constructed cell models by treating Pulmonary Artery Smooth Muscle Cells (PASMCs) with platelet-derived growth factor-BB (PDGF-BB). The effects of different concentrations of PDGF-BB on the activity of PASMCs were tested by cell counting kit-8 (CCK-8). The upstream lncRNA of miR-382-3p was screened and confirmed through bioinformatics analysis, RNA pull-down, quantitative reverse transcription polymerase chain reaction (qRT-PCR), dual luciferase reporter gene and RNA immunoprecipitation assays. The effects of GAS5/miR-382-3p axis on the viability, migration, and expressions of autophagy- and angiogenesis-related proteins were confirmed by rescue experiments (CCK-8, wound healing and western blot). In vivo, animal models by perfusing autologous blood vessels, the effects of GAS5 overexpression or silencing on the expressions of miR-382-3p, angiogenesis- and autophagy-related genes, mean pulmonary arterial pressure (mPAP) and pulmonary artery wall were determined by biological signal acquisition system, hematoxylin-eosin staining, qRT-PCR and western blot.

RESULTS

PDGF-BB dose-dependently promoted PASMCs viability. XIST and GAS5 expressions in PASMCs were affected by the concentration of PDGF-BB, but only GAS5 can be pulled down by miR-382-3p probe. GAS5 targeted miR-382-3p to inhibit the viability and migration of PAMSCs, mPAP in CTEPH rats, pulmonary artery wall thickening and angiogenesis, and promote autophagy.

CONCLUSIONS

GAS5/miR-382-3p axis is involved in the regulation of pulmonary artery remodeling and autophagy in CTEPH.

Long Non-Coding RNAs in Systemic Lupus Erythematosus: New Insights into Disease Pathogenesis and Diagnosis

Systemic lupus erythematosus (SLE) is a remarkable heterogeneous autoimmune disease that is sometimes hard to diagnose at the early stage and can lead to premature mortality. Long non-coding RNAs (lncRNAs) are a class of non-protein-coding RNAs greater than 200 nucleotides in length that can regulate gene expression in various human diseases, including SLE. Peripheral blood samples and renal tissue samples from SLE patients were used for study. Abnormally expressed lncRNAs in SLE have been shown to influence several signaling pathways, including the IFN-I, MAPK and WNT pathways. This can affect cellular phenotypes like cell activation, differentiation skewing, cytokine production, and cell apoptosis. Many of the reported lncRNAs may be useful for diagnosing, evaluating progression, and predicting potential organ damage in SLE patients. While numerous lncRNAs play important roles in SLE, more basic and clinical studies are warranted to clarify the function of these regulatory molecules and determine their diagnostic value.

N7-methylguanosine modification of lncRNAs in a rat model of hypoxic pulmonary hypertension: a comprehensive analysis

Background

Long non-coding RNAs (lncRNAs) play a critical role in the pathogenesis of hypoxic pulmonary hypertension (HPH). The role of N7-methylguanosine (m7G) modification in lncRNAs has received increased attentions in recent years. However, the m7G-methylation of lncRNA in HPH has yet to be determined. We have therefore performed a transcriptome-wide analysis of m7G lncRNAs in HPH.

Results

Differentially-expressed m7Gs were detected in HPH, and m7G lncRNAs were significantly upregulated compared with non-m7G lncRNAs in HPH. Importantly, this was the first time that the upregulated m7G lncXR_591973 and m7G lncXR_592398 were identified in HPH.

Conclusion

This study provides the first m7G transcriptome-wide analysis of HPH. Importantly, two HPH-associated m7G lncRNAs were identified, although their clinical significance requires further validation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-021-08188-8.

Expression of the microRNA-30 family in pulmonary arterial hypertension and the role of microRNA-30d-5p in the regulation of pulmonary arterial smooth muscle cell toxicity and apoptosis

The biological processes of pulmonary artery vascular smooth muscle cells (PA-SMCs) and pulmonary artery endothelial cells in pulmonary arterial hypertension (PAH) are generally abnormal, with increased levels of proliferation and reduced levels of apoptosis. Although microRNAs (miRNAs/miRs) participate in a number of biological processes in a variety of diseases, such as tumors and infections, studies on the association between miRNAs and PAH are limited. In the present study, blood samples were collected from 6 patients with patent ductus arteriosus. The experimental group included 3 patients with severe PAH, while the control group included 3 patients without PAH. Microarray technology was used to detect the presence of any associated miRNAs. Moreover, a rat PAH model was established via left lung resection followed by monocrotaline injection, involving a total of 8 rats in the PAH group and 8 untreated rat in the control group. Reverse transcription-quantitative PCR was performed to verify the expression levels of the miR-30 family in the animal model. miR-30d-5p mimics and anti-miR-30d-5p were transfected into primary cultured PA-SMCs. Levels of cytotoxicity and cell apoptosis were examined, and Notch-3 expression levels were studied using western blotting. The results of the present study demonstrated that miR-30d-5p expression was downregulated in both patient blood and animal models of the PAH group compared with control groups. In primary cultured PA-SMCs, overexpression of miR-30d-5p attenuated the platelet-derived growth factor-induced toxicity of PA-SMCs, while knockdown of miR-30d-5p resulted in the increased toxicity of PA-SMCs compared with control group. The apoptosis rate of PA-SMCs increased with the overexpression of miR-30d-5p compared with control group. Moreover, the expression levels of Notch-3 in the miR-30d-5p group were significantly reduced compared with the anti-miR-30d-5p and miR-NC groups. In total, 10 circulating miRNAs that may be associated with PAH were discovered in the present study. Moreover, the expression of the miR-30 family was verified in animal models in vivo, and seven miRNAs in this family were discovered that may be associated with PAH. Additionally, miR-30d-5p was downregulated in both patients with PAH and animal models compared with control groups. Thus, the results of the present study demonstrated that the regulatory mechanism underlying PA-SMCs may be via the Notch-3 signaling pathway.

Non-Coding RNA Networks in Pulmonary Hypertension

Non-coding RNAs (ncRNAs) are involved in various cellular processes. There are several ncRNA classes, including microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs). The detailed roles of these molecules in pulmonary hypertension (PH) remain unclear. We systematically collected and reviewed reports describing the functions of ncRNAs (miRNAs, lncRNAs, and circRNAs) in PH through database retrieval and manual literature reading. The characteristics of identified articles, especially the experimental methods, were carefully reviewed. Furthermore, regulatory networks were constructed using ncRNAs and their interacting RNAs or genes. These data were extracted from studies on pulmonary arterial smooth muscle cells, pulmonary artery endothelial cells, and pulmonary artery fibroblasts. We included 14 lncRNAs, 1 circRNA, 74 miRNAs, and 110 mRNAs in the constructed networks. Using these networks, herein, we describe the current knowledge on the role of ncRNAs in PH. Moreover, these networks actively provide an improved understanding of the roles of ncRNAs in PH. The results of this study are crucial for the clinical application of ncRNAs.

Long non-coding RNA TUG1 knockdown prevents neurons from death to alleviate acute spinal cord injury via the microRNA-338/BIK axis

Taurine up-regulated gene 1 (TUG1) is a cancer-associated long noncoding RNA (lncRNA) and engages in the development of spinal cord injury (SCI), a suffering neuropathological disorder. However, the regulatory role of TUG1 in acute SCI (ASCI) is still underdetermined. RT-qPCR and western blot analysis were applied to measure the expression of TUG1, microRNA-338 (miR-338), Bcl2-interacting killer (BIK), cleaved caspase 3 (c-caspase 3) and hypoxia-inducible factor-1 alpha (HIF-1α) in ASCI rats and hypoxic cells. Cell death was evaluated using flow cytometric analysis. The relationships among miR-338, TUG1 or BIK were confirmed by luciferase reporter assay, RNA immunoprecipitation and RNA pull-down. Accordingly, we monitored higher expression of TUG1 and BIK, but lower expression of miR-338 in ASCI rats and hypoxic cells. In vitro, hypoxia expedited cell death and c-caspase 3 levels. In vivo, ASCI rats were successfully developed as evidenced by diminished Basso-Beattie-Bresnahan (BBB) locomotor score and enhanced c-caspase 3 and HIF-1α expression. Nevertheless, TUG1 knockdown mitigated the cell death in ASCI rats and hypoxic cells. Mechanically, TUG1 interacted with miR-338 to regulate the BIK expression. Together, TUG1 silencing could alleviate the death in neurons and ASCI models via modulating the miR-338/BIK axis.

Role of Long Non-Coding RNAs in Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is a debilitating condition of the pulmonary circulatory system that occurs in patients of all ages and if untreated, eventually leads to right heart failure and death. Despite existing medical treatment options that improve survival and quality of life, the disease remains incurable. Thus, there is an urgent need to develop novel therapies to treat this disease. Emerging evidence suggests that long non-coding RNAs (lncRNAs) play critical roles in pulmonary vascular remodeling and PAH. LncRNAs are implicated in pulmonary arterial endothelial dysfunction by modulating endothelial cell proliferation, angiogenesis, endothelial mesenchymal transition, and metabolism. LncRNAs are also involved in inducing different pulmonary arterial vascular smooth muscle cell phenotypes, such as cell proliferation, apoptosis, migration, regulation of the phenotypic switching, and cell cycle. LncRNAs are essential regulators of gene expression that affect various diseases at the chromatin, transcriptional, post-translational, and even post-translational levels. Here, we focus on the role of LncRNAs and their molecular mechanisms in the pathogenesis of PAH. We also discuss the current research challenge and potential biomarker and therapeutic potentials of lncRNAs in PAH.

Novel molecular insights and public omics data in pulmonary hypertension

Pulmonary hypertension is a rare disease with high morbidity and mortality which mainly affects women of reproductive age. Despite recent advances in understanding the pathogenesis of pulmonary hypertension, the high heterogeneity in the presentation of the disease among different patients makes it difficult to make an accurate diagnosis and to apply this knowledge to effective treatments. Therefore, new studies are required to focus on translational and personalized medicine to overcome the lack of specificity and efficacy of current management. Here, we review the majority of public databases storing 'omics' data of pulmonary hypertension studies, from animal models to human patients. Moreover, we review some of the new molecular mechanisms involved in the pathogenesis of pulmonary hypertension, including non-coding RNAs and the application of 'omics' data to understand this pathology, hoping that these new approaches will provide insights to guide the way to personalized diagnosis and treatment.

The lncRNA PAHRF functions as a competing endogenous RNA to regulate MST1 expression by sponging miR-23a-3p in pulmonary arterial hypertension

BACKGROUND

Emerging evidence has shown that long non-coding RNA (lncRNA) plays important roles in the development of pulmonary arterial hypertension (PAH). However, some new lncRNAs in patients with PAH are still lacking research. Herein, we examined the expression and role of lncRNA (pulmonary arterial hypertension related factor, PAHRF) in PAH.

METHODS

LncRNA PAHRF expression and localization were analyzed by realtime PCR and fluorescence in situ hybridization. Proliferation and apoptosis were detected by MTT, CCK-8, EDU staining, JC-1 assay, flow cytometry and western blotting. Luciferase activity assay was used to identify PAHRF/ miR-23a-3p/serine/threonine kinase 4 (STK4/MST1) interaction.

RESULTS

LncRNA PAHRF was down-regulated in both the PAs of PAH patients and hypoxic human pulmonary artery smooth muscle cells (PASMCs). The overexpression of PAHRF inhibited the proliferation and promoted the apoptosis of PASMCs. Similarly, we also found PAHRF overexpression decreased the proliferation under hypoxia condition. Knockdown of PAHRF exerted the opposite effects. Luciferase activity assay proved molecular binding between PAHRF and hsa-miR-23a-3p. Moreover, MST1 was confirmed to be the putative target gene and regulated by PAHRF/miR-23a-3p. In addition, we explored the molecular mechanism regulating the expression of miR-23a-3p, and found that lncRNA PAHRF acted as an endogenous sponge for miR-23a-3p, and silencing lncRNA PAHRF could up-regulate the expression of miR-23a-3p. On the contrary, PAHRF-overexpressing plasmid inhibited the expression of miR-23a-3p in hypoxia.

CONCLUSIONS

Our present study reveals a novel PAH regulating model that is composed of PAHRF, miR-23a-3p, and MST1. The aim of this study is probably going to provide a new explanation and give a further understanding of the occurrence of vascular remodeling in PAH from the perspective competing endogenous RNA hypothesis.

lnc-Rps4l-encoded peptide RPS4XL regulates RPS6 phosphorylation and inhibits the proliferation of PASMCs caused by hypoxia

Pulmonary artery smooth muscle cells (PASMCs) proliferation caused by hypoxia is an important pathological process of pulmonary hypertension (PH). Prevention of PASMCs proliferation can effectively reduce PH mortality. Long non-coding RNAs (lncRNAs) are involved in the proliferation process. Recent evidence has demonstrated that functional peptides encoded by lncRNAs play important roles in cell pathophysiological process. Our previous study has demonstrated that lnc-Rps4l with high coding ability mediates the PASMCs proliferation under hypoxic conditions. We hypothesize in this study that a lnc-Rps4l-encoded peptide is involved in hypoxic-induced PASMCs proliferation. The presence of peptide 40S ribosomal protein S4 X isoform-like (RPS4XL) encoded by lnc-Rps4l in PASMCs under hypoxic conditions was confirmed by bioinformatics, immunofluorescence, and immunohistochemistry. Inhibition of proliferation by the peptide RPS4XL was demonstrated in hypoxic PASMCs by MTT, bromodeoxyuridine (BrdU) incorporation, and immunofluorescence assays. By using the bioinformatics, coimmunoprecipitation (coIP), and mass spectrometry, RPS6 was identified to interact with RPS4XL. Furthermore, lnc-Rps4l-encoded peptide RPS4XL inhibited the RPS6 process via binding to RPS6 and inhibiting RPS6 phosphorylation at p-RPS6 (Ser240+Ser244) phosphorylation site. These results systematically elucidate the role and regulatory network of Rps4l-encoded peptide RPS4XL in PASMCs proliferation. These discoveries provide potential targets for early diagnosis and a leading compound for treatment of hypoxic PH.

LncRNA HOXA-AS3 Promotes the Progression of Pulmonary Arterial Hypertension through Mediation of miR-675-3p/PDE5A Axis

Pulmonary arterial hypertension (PAH) seriously threatens the elder people. Long non-coding RNAs (lncRNAs) are involved in multiple diseases. However, the study of the lncRNAs in the occurrence of PAH is just beginning. For this, we sought to explore the biological function of lncRNA HOXA cluster antisense RNA 3 (HOXA-AS3) in PAH. Hypoxia (HYP) was used to mimic in vitro model of PAH. Gene and protein expressions in cells were detected by q-PCR and Western blotting, respectively. In addition, cell proliferation and viability were tested by CCK-8 and MTT assay. Cell apoptosis was measured by flow cytometry. Wound healing was used to detect cell migration. Furthermore, the connection of HOXA-AS3, miR-675-3p, and phosphodiesterase 5A (PDE5A) was verified by dual-luciferase report assay. HOXA-AS3 and PDE5A were upregulated in human pulmonary artery smooth muscle cells (HPASMCs) in the presence of HYP, while miR-675-3p was downregulated. Moreover, knockdown of HOXA-AS3 suppressed the growth and migration of HPASMCs, but induced the apoptosis. Overexpression of miR-675-3p achieved the same effect. MiR-675-3p inhibitor or overexpression of PDE5A notably reversed the inhibitory effect of HOXA-AS3 knockdown on PAH. Finally, HOXA-AS3 could sponge miR-675-3p, and PDE5A was directly targeted by miR-675-3p. HOXA-AS3 increased the development of PAH via regulation of miR-675-3p/PDE5 axis, which could be the potential biomarker for treatment of PAH.

The Influenza A Virus H3N2 Triggers the Hypersusceptibility of Airway Inflammatory Response via Activating the lncRNA TUG1/miR-145-5p/NF-κB Pathway in COPD

Background: Patients with chronic obstructive pulmonary disease (COPD) are more susceptible to influenza A virus (IAV) with more severe symptoms, yet the underlying molecular mechanisms of the hypersusceptibility of airway inflammatory response remain unclear. Methods: The primary human bronchial epithelial cells (pHBECs) were isolated from normal and COPD bronchial tissues (NHBE and DHBE) and cultured with/without IAV infection in vitro. DHBE cells were exposed to IAV for 24 h after knockdown of lncRNA TUG1 with short hairpin RNA (shRNA). Gain-of-function assays were performed with the miR-145-5p inhibitor and NF-κBp65 transfection. The expressions of lncRNA TUG1, miR-145-5p, phospho-NF-κBp65, NF-κBp65, TNF-α, and (Interleukin) IL-1β were examined with qRT-PCR, Western blotting, and ELISA. The interactions of lncRNA TUG1, miR-145-5p, and NF-κB were verified with luciferase reporter assay. Results: The expressions of lncRNA TUG1, phospho-NF-κBp65, TNF-α, and IL-1β were increased significantly in pHBECs after being infected with IAV for 24 h (all p0.05). The detailed time analysis revealed that the NF-κBp65 in DHBE was activated earlier than that in NHBE by Western blotting and immunofluorescence. Knockdown of lncRNA TUG1 and miR-145-5p mimic attenuated the expressions of NF-κBp65, TNF-α, and IL-1β significantly. The miR-145-5p inhibitor and NF-κBp65 transfection reversed the attenuated expressions of NF-κBp65, TNF-α, and IL-1β. Conclusion: The IAV causes the hypersusceptibility of airway inflammatory response, which may be closely associated with more severe symptoms in AECOPD patients. The lncRNA TUG1 inhibitor may be a promising therapeutic strategy for AECOPD caused by IAV.

Cell Tracking Suggests Pathophysiological and Therapeutic Role of Bone Marrow Cells in Sugen5416/Hypoxia Rat Model of Pulmonary Arterial Hypertension

BACKGROUND

The mechanism of vascular remodelling in pulmonary arterial hypertension (PAH) remains unclear. Hence, defining the origin of cells constituting intractable vascular lesions in PAH is expected to facilitate therapeutic progress. Herein, we aimed to evaluate the origin of intractable vascular lesions in PAH rodent models via bone marrow (BM) and orthotopic lung transplantation (LT).

METHODS

To trace BM-derived cells, we prepared chimeric rats transplanted with BM cells from green fluorescent protein (GFP) transgenic rats. Male rats were transplanted with lungs obtained from female rats and vice versa. Pulmonary hypertension was induced in the transplanted rats via Sugen5416 treatment and subsequent chronic hypoxia (Su/Hx).

RESULTS

In the chimeric Su/Hx models, GFP-positive cells were observed in the pulmonary vascular area. Moreover, the right ventricular systolic pressure was significantly lower compared with wild-type Su/Hx rats without BM transplantation (P = 0.009). PAH suppression was also observed in rats that received allograft transplanted BM transplantation. In male rats that received LT and Su/Hx, BM-derived cells carrying the Y chromosome were also detected in neointimal occlusive lesions of the transplanted lungs received from female rats.

CONCLUSIONS

BM-derived cells participate in pulmonary vascular remodelling in the Su/Hx rat model, whereas BM transplantation may contribute to suppression of development of PAH.

Astragaloside IV attenuates hypoxia‑induced pulmonary vascular remodeling via the Notch signaling pathway

The Notch signaling pathway participates in pulmonary artery smooth muscle cell (PASMC) proliferation and apoptosis. Astragaloside IV (AS-IV) is an effective antiproliferative treatment for vascular diseases. The present study aimed to investigate the protective effects and mechanisms underlying AS-IV on hypoxia-induced PASMC proliferation and pulmonary vascular remodeling in pulmonary arterial hypertension (PAH) model rats. Rats were divided into the following four groups: i) normoxia; ii) hypoxia (10% O₂); iii) treatment, hypoxia + intragastrical administration of AS-IV (2 mg/kg) daily for 28 days; and iv) DAPT, hypoxia + AS-IV treatment + subcutaneous administration of DAPT (10 mg/kg) three times daily. The effects of AS-IV treatment on the development of hypoxia-induced PAH, right ventricle (RV) hypertrophy and pulmonary vascular remodeling were examined. Furthermore, PASMCs were treated with 20 µmol/l AS-IV under hypoxic conditions for 48 h. To determine the effect of Notch signaling in vascular remodeling and the potential mechanisms underlying AS-IV treatment, 5 mmol/l γ-secretase inhibitor [N-[N-(3,5-difluorophenacetyl)-L-alanyl]-S-phenylglycine t-butyl ester (DAPT)] was used. Cell viability and apoptosis were determined by performing the MTT assay and flow cytometry, respectively. Immunohistochemistry was conducted to detect the expression of proliferating cell nuclear antigen (PCNA). Moreover, the mRNA and protein expression levels of Notch-3, Jagged-1, hes family bHLH transcription factor 5 (Hes-5) and PCNA were measured via reverse transcription-quantitative PCR and western blotting, respectively. Compared with the normoxic group, hypoxia-induced PAH model rats displayed characteristics of PAH and RV hypertrophy, whereas AS-IV treatment alleviated PAH and prevented RV hypertrophy. AS-IV also inhibited hypoxia-induced pulmonary vascular remodeling, as indicated by reduced wall thickness and increased lumen diameter of pulmonary arterioles, and decreased muscularization of distal pulmonary vasculature in hypoxia-induced PAH model rats. Compared with normoxia, hypoxia promoted PASMC proliferation in vitro, whereas AS-IV treatment inhibited hypoxia-induced PASMC proliferation by downregulating PCNA expression in vitro and in vivo. In hypoxia-treated PAH model rats and cultured PASMCs, AS-IV treatment reduced the expression levels of Jagged-1, Notch-3 and Hes-5. Furthermore, Notch signaling inhibition via DAPT significantly inhibited the pulmonary vascular remodeling effect of AS-IV in vitro and in vivo. Collectively, the results indicated that AS-IV effectively reversed hypoxia-induced pulmonary vascular remodeling and PASMC proliferation via the Notch signaling pathway. Therefore, the present study provided novel insights into the mechanism underlying the use of AS-IV for treatment of vascular diseases, such as PAH.

Emerging role of long non-coding RNAs in pulmonary hypertension and their molecular mechanisms (Review)

Pulmonary hypertension (PH) is a life-threatening cardiopulmonary condition caused by several pathogenic factors. All types of PH are characterized by the excessive proliferation of pulmonary artery endothelial cells and pulmonary artery smooth muscle cells, apoptosis resistance, pulmonary vascular remodeling, sustained elevated pulmonary arterial pressure, right heart failure and even death. Over the past decade, next generation sequencing, particularly RNA-sequencing, has identified some long non-coding RNAs (lncRNAs) that may act as regulators of cell differentiation, proliferation and apoptosis. Studies have shown that lncRNAs are closely associated with the development of several diseases, including cardiovascular diseases. In addition, a number of studies have reported that lncRNAs, including maternally expressed gene 3, metastasis-associated lung adenocarcinoma transcript 1, taurine upregulated 1 and cancer susceptibility candidate 2, serve important roles in the pathogenesis of PH. Despite the development of novel drug treatments, the mortality rate of PH remains high with no evident downward trend. Therefore, certain lncRNAs may be considered as therapeutic targets for the treatment of incurable PH. The present review summarizes the latest research on lncRNAs and PH, aiming to briefly describe PH-associated lncRNAs and their mechanisms of action.

Overexpressed lncRNA AC068039.4 Contributes to Proliferation and Cell Cycle Progression of Pulmonary Artery Smooth Muscle Cells Via Sponging miR-26a-5p/TRPC6 in Hypoxic Pulmonary Arterial Hypertension

BACKGROUND

Hypoxic pulmonary hypertension (HPH) is a devastating and incurable disease characterized by pulmonary vascular remodeling, resulting in right heart failure and even death. Accumulated evidence has confirmed long coding RNAs (lncRNAs) are involved in hypoxia-induced pulmonary vascular remodeling in HPH. The exact mechanism of lncRNA in hypoxic pulmonary hypertension remains unclear.

METHODS

Microarray analysis was applied to investigate the profiles of lncRNA expression in pulmonary artery smooth muscle cells (PASMCs) cultured under hypoxia and normoxia condition. qRT-PCR was performed for the expression of lncRNAs, miRNA, and mRNAs, western blot analysis was employed for the detection of the expression of proteins. CCK-8 and transwell chamber assay were applied for the assessment of PASMC proliferation and migration, respectively. Besides, flow cytometry was performed for assessments of cell cycle progression. The binding between AC068039.4 and miR-26a-5p, miR-26a-5p, and TRPC6 3'UTR was detected by dual luciferase reporter assay.

RESULTS

A total of 1,211 lncRNAs (698 up-regulated and 513 down-regulated) were differently expressed in hypoxia-induced PASMCs. Consistent with microarray analysis, quantitative PCR verified that AC068039.4 was obviously up-regulated in hypoxia-induced PASMCs. Knocking down AC068039.4 alleviated proliferation and migration of PASMCs and regulated cell cycle progression through inhibiting cells entering the G0/G1 cell cycle phase. Further experiment indicated AC068039.4 promoted hypoxic PASMCs proliferation via sponging miR-26-5p. In addition, transient receptor potential canonical 6 (TRPC6) was confirmed to be a target gene of miR-26a-5p.

CONCLUSION

In conclusion, downregulation of lncRNA AC068039.4 inhibited pulmonary vascular remodeling through AC068039.4/miR-26a-5p/TRPC6 axis, providing new therapeutic insights for the treatment of HPH.

Suspended in time: Molecular responses to hibernation also promote longevity

Aging in most animals is an inevitable process that causes or is a result of physiological, biochemical, and molecular changes in the body, and has a strong influence on an organism's lifespan. Although advancement in medicine has allowed humans to live longer, the prevalence of age-associated medical complications is continuously burdening older adults worldwide. Current animal models used in research to study aging have provided novel information that has helped investigators understand the aging process; however, these models are limiting. Aging is a complex process that is regulated at multiple biological levels, and while a single manipulation in these models can provide information on a process, it is not enough to understand the global regulation of aging. Some mammalian hibernators live up to 9.8-times higher than their expected average lifespan, and new research attributes this increase to their ability to hibernate. A common theme amongst these mammalian hibernators is their ability to greatly reduce their metabolic rate to a fraction of their normal rate and initiate cytoprotective responses that enable their survival. Metabolic rate depression is strictly regulated at different biological levels in order to enable the animal to not only survive, but to also do so by relying mainly on their limited internal fuels. As such, understanding both the global and specific regulatory mechanisms used to promote survival during hibernation could, in theory, allow investigators to have a better understanding of the aging process. This can also allow pharmaceutical industries to find therapeutics that could delay or reverse age-associated medical complications and promote healthy aging and longevity in humans.

Long Non-coding RNA TUG1 Modulates Expression of Elastin to Relieve Bronchopulmonary Dysplasia via Sponging miR-29a-3p

Objective: Multiple studies have highlighted that long non-coding RNAs (lncRNAs) may exert paramount roles in relieving bronchopulmonary dysplasia (BPD). The aim of our investigation is to probe the role and mechanism of lncRNA taurine upregulated gene 1 (TUG1) in BPD. Methods: The current mouse model of BPD was simulated by induction of hyperoxia, and hyperoxia-induced mouse type II alveolar epithelial (MLE-12) (MLE-12) cells were established as a cellular model. Quantitative real-time polymerase chain reaction (qRT-PCR) was applied to determine relative expressions of TUG1, miR-29a-3p, and elastin (ELN). We assessed cell apoptosis by TdT-mediated dUTP-biotin nick-end labeling (TUNEL) staining. Western blot was used for detection of apoptosis-related proteins. Moreover, cell viability was tested by cell counting kit-8 (CCK-8) assay. Inflammatory factors were measured by enzyme-linked immunosorbent assay (ELISA). Dual-luciferase reporter (DLR) assay was employed to confirm relationship between genes. Results: Upregulation of miR-29a-3p was found in lung tissues of BPD mice compared with lung tissues without BPD, while downregulations of TUG1 and ELN were discovered in BPD tissues in comparison with tissues without BPD. Increasing TUG1 was shown to alleviate lung injury of BPD mice and promote proliferation of hyperoxia-induced MLE-12 cells. Meanwhile, TUG1 inhibited inflammatory response and cell apoptosis in lung tissues of BPD mice and hyperoxia-induced MLE-12 cells. miR-29a-3p was targeted by TUG1 and negatively modulated by TUG1. ELN was inversely regulated by miR-29a-3p. Meantime, suppressive effects of TUG1 on apoptosis and inflammation were reversed by decreasing ELN or increasing miR-29a-3p in hyperoxia-induced MLE-12 cells. Conclusion: lncRNA TUG1 relieved BPD through regulating the miR-29a-3p/ELN axis, which provided a therapeutic option to prevent or ameliorate BPD.