miR-140-5p regulates hypoxia-mediated human pulmonary artery smooth muscle cell proliferation, apoptosis and differentiation by targeting Dnmt1 and promoting SOD2 expression

The Role of Clonal Hematopoiesis of Indeterminant Potential and DNA (Cytosine-5)-Methyltransferase Dysregulation in Pulmonary Arterial Hypertension and Other Cardiovascular Diseases

DNA methylation is an epigenetic mechanism that regulates gene expression without altering gene sequences in health and disease. DNA methyltransferases (DNMTs) are enzymes responsible for DNA methylation, and their dysregulation is both a pathogenic mechanism of disease and a therapeutic target. DNMTs change gene expression by methylating CpG islands within exonic and intergenic DNA regions, which typically reduces gene transcription. Initially, mutations in the DNMT genes and pathologic DNMT protein expression were found to cause hematologic diseases, like myeloproliferative disease and acute myeloid leukemia, but recently they have been shown to promote cardiovascular diseases, including coronary artery disease and pulmonary hypertension. We reviewed the regulation and functions of DNMTs, with an emphasis on somatic mutations in DNMT3A, a common cause of clonal hematopoiesis of indeterminant potential (CHIP) that may also be involved in the development of pulmonary arterial hypertension (PAH). Accumulation of somatic mutations in DNMT3A and other CHIP genes in hematopoietic cells and cardiovascular tissues creates an inflammatory environment that promotes cardiopulmonary diseases, even in the absence of hematologic disease. This review summarized the current understanding of the roles of DNMTs in maintenance and de novo methylation that contribute to the pathogenesis of cardiovascular diseases, including PAH.

Mechanism of Hypoxia-Mediated Smooth Muscle Cell Proliferation Leading to Vascular Remodeling

Vascular remodeling refers to changes in the size, contraction, distribution, and flow rate of blood vessels and even changes in vascular function. Vascular remodeling can cause cardiovascular and cerebrovascular diseases. It can also lead to other systemic diseases, such as pulmonary hypertension, pulmonary atherosclerosis, chronic obstructive pulmonary disease, stroke, and ascites of broilers. Hypoxia is one of the main causes of vascular remodeling. Prolonged hypoxia or intermittent hypoxia can lead to loss of lung ventilation, causing respiratory depression, irregular respiratory rhythms, and central respiratory failure. Animals that are unable to adapt to the highland environment are also prone to sustained constriction of the small pulmonary arteries, increased resistance to pulmonary circulation, and impaired blood circulation, leading to pulmonary hypertension and right heart failure if they live in a highland environment for long periods of time. However, limited studies have been found on the relationship between hypoxia and vascular remodeling. Therefore, this review will explore the relationship between hypoxia and vascular remodeling from the aspects of endoplasmic reticulum stress, mitochondrial dysfunction, abnormal calcium channel, disordered cellular metabolism, abnormal expression of miRNA, and other factors. This will help to understand the detailed mechanism of hypoxia-mediated smooth muscle cell proliferation and vascular remodeling for the better treatment and management of diseases due to vascular remodeling.

Effects of hypoxia and reoxygenation on mitochondrial functions and transcriptional profiles of isolated brain and muscle porcine cells

Oxygen fluctuations might occur in mammalian tissues under physiological (e.g. at high altitudes) or pathological (e.g. ischemia-reperfusion) conditions. Mitochondria are the key target and potential amplifiers of hypoxia-reoxygenation (H-R) stress. Understanding the mitochondrial responses to H-R stress is important for identifying adaptive mechanisms and potential therapeutic solutions for pathologies associated with oxygen fluctuations. We explored metabolic response to H-R stress in two tissue types (muscle and brain) with different degrees of hypoxia tolerance in a domestic pig Sus scrofa focusing on the cellular responses independent of the systemic regulatory mechanisms. Isolated cells from the skeletal muscle (masseter) and brain (thalamus) were exposed to acute short-term (15 min) hypoxia followed by reoxygenation. The mitochondrial oxygen consumption, reactive oxygen species (ROS) production rates and transcriptional profiles of hypoxia-responsive mRNA and miRNA were determined. Mitochondria of the porcine brain cells showed a decrease in the resting respiration and ATP synthesis capacity whereas the mitochondria from the muscle cells showed robust respiration and less susceptibility to H-R stress. ROS production was not affected by the short-term H-R stress in the brain or muscle cells. Transcriptionally, prolyl hydroxylase domain protein EGLN3 was upregulated during hypoxia and suppressed during reoxygenation in porcine muscle cells. The decline in EGLN3 mRNA during reoxygenation was accompanied by an upregulation of hypoxia-inducible factor subunit α (HIF1A) transcripts in the muscle cells. However, in the brain cells, HIF1A mRNA levels were suppressed during reoxygenation. Other functionally important transcripts and miRNAs involved in antioxidant response, apoptosis, inflammation, and substrate oxidation were also differentially expressed between the muscle and brain cells. Suppression of miRNA levels during acute intermittent hypoxia was stronger in the brain cells affecting ~ 55% of all studied miRNA transcripts than in the muscle cells (~ 25% of miRNA) signifying transcriptional derepression of the respective mRNA targets. Our study provides insights into the potential molecular and physiological mechanisms contributing to different hypoxia sensitivity of the studied tissues and can serve as a starting point to better understand the biological processes associated with hypoxia stress, e.g. during ischemia and reperfusion.

Biomarker-based approach to determine etiology and severity of pulmonary hypertension: Focus on microRNA

Pulmonary arterial hypertension (PAH) is characterized by remodeling of the pulmonary arteries, and defined by elevated pulmonary arterial pressure, measured during right heart catheterization. There are three main challenges to the diagnostic and therapeutic process of patients with PAH. First, it is difficult to differentiate particular PAH etiology. Second, invasive diagnostic is required to precisely determine the severity of PAH, and thus to qualify patients for an appropriate treatment. Third, the results of treatment of PAH are unpredictable and remain unsatisfactory. MicroRNAs (miRNAs) are small non-coding RNAs that regulate post transcriptional gene-expression. Their role as a prognostic, and diagnostic biomarkers in many different diseases have been studied in recent years. MiRNAs are promising novel biomarkers in PAH due to their activity in various molecular pathways and processes underlying PAH. Lack of biomarkers to differentiate between particular PAH etiology and evaluate the severity of PAH, as well as paucity of therapeutic targets in PAH open a new field for the possibility to use miRNAs in these applications. In our article, we discuss the potential of miRNAs use as diagnostic tools, prognostic biomarkers and therapeutic targets in PAH.

Epigenetic Control of Vascular Smooth Muscle Cell Function in Atherosclerosis: A Role for DNA Methylation

Atherosclerosis is a complex vascular inflammatory disease in which multiple cell types are involved, including vascular smooth muscle cells (VSMCs). In response to vascular injury and inflammatory stimuli, VSMCs undergo a "phenotypic switching" characterized by extracellular matrix secretion, loss of contractility, and abnormal proliferation and migration, which play a key role in the progression of atherosclerosis. DNA methylation modification is an important epigenetic mechanism that plays an important role in atherosclerosis. Studies investigating abnormal DNA methylation in patients with atherosclerosis have determined a specific DNA methylation profile, and proposed multiple pathways and genes involved in the etiopathogenesis of atherosclerosis. Recent studies have also revealed that DNA methylation modification controls VSMC function by regulating gene expression involved in atherosclerosis. In this review, we summarize the recent advances regarding the epigenetic control of VSMC function by DNA methylation in atherosclerosis and provide insights into the development of VSMC-centered therapeutic strategies.

Hsa_circ_0016070/micro‐340‐5p Axis Accelerates Pulmonary Arterial Hypertension Progression by Upregulating TWIST1 Transcription Via TCF4/β‐Catenin Complex

Background

Hypoxia is considered a major leading cause of pulmonary hypertension (PH). In this study, the roles and molecular mechanism of circ_0016070 in PH were studied.

Methods and Results

The expression of circ_0016070 in serum samples, human pulmonary artery smooth muscle cells and hypoxia/monocrotaline‐treated rats was determined by real‐time quantitative polymerase chain reaction. Cell viability, migration, and apoptosis were analyzed by Cell Counting Kit‐8, wound healing, flow cytometry, and TUNEL (terminal deoxynucleotidyl transferase dUTP nick end labeling) assays, respectively. The molecular interactions were validated using RNA immunoprecipitation, chromatin immunoprecipitation, and dual luciferase reporter assays. The levels of phenotype switch‐related proteins were evaluated by Western blot and immunohistochemistry. The pathological characteristics were assessed using hematoxylin and eosin staining. circ_0016070 was highly expressed in the serum samples, hypoxia‐induced pulmonary artery smooth muscle cells and pulmonary arterial tissues of PH rats. Downregulation of circ_0016070 ameliorated the excessive proliferation, migration, vascular remodeling, and phenotypic transformation but enhanced cell apoptosis in the PH rat model. In addition, micro (miR)‐340‐5p was verified as a direct target of circ_0016070 and negatively regulated TCF4 (transcription factor 4) expression. TCF4 formed a transcriptional complex with β‐catenin to activate TWIST1 (Twist family bHLH transcription factor 1) expression. Functional rescue experiments showed that neither miR‐340‐5p inhibition nor TWIST1 or TCF4 upregulation significantly impeded the biological roles of circ_0010670 silencing in PH.

Conclusions

These results uncovered a novel mechanism by which circ_0016070 play as a competing endogenouse RNA of miR‐340‐5p to aggravate PH progression by promoting TCF4/β‐catenin/TWIST1 complex, which may provide potential therapeutic targets for PH.

Human pulmonary artery smooth muscle cell dysfunction is regulated by miR-509-5p in hypoxic environment

Reportedly, dysfunction of human pulmonary arterial smooth muscle cells (PASMCs) is associated with the pathogenesis of pulmonary arterial hypertension (PAH). Herein, the role of miR-509-5p in hypoxia-induced PASMCs and the underlying mechanism were explored. PASMCs were cultured under both normoxia and hypoxia conditions. Quantitative real-time polymerase-chain reaction (qPCR) was employed for quantifying the expressions of miR-509-5p and DNMT1 mRNA in the serum of PAH patients and PASMCs. MiR-509-5p mimics and inhibitors were then, respectively, transfected into PAMSCs, and CCK-8 and Transwell assays were utilized to detect PASMCs' proliferation and migration. Flow cytometry was executed for evaluating PASMCs' apoptosis. Interrelation between miR-509-5p and DNMT1 was determined utilizing bioinformatics analysis and dual-luciferase reporter assay. Western blot assay was used to detect the expression of DNMT1 or SOD2. MiR-509-5p in serum samples of patients with PAH as well as hypoxia-induced PASMCs was significantly down-regulated, whereas DNMT1 was markedly up-regulated. MiR-509-5p mimics reduces the proliferation and migration of PASMCs, but promotes the apoptosis; conversely, miR-509-5p inhibitors exerted opposite effects. DNMT1 was identified as a target gene of miR-509-5p, and overexpression of DNMT1 reversed the biological functions of miR-509-5p in regulating the phenotypes of PAMSCs. MiR-509-5p up-regulated the expression of SOD2 by down-regulating DNMT1. MiR-509-5p regulates the proliferation, migration and apoptosis of PASMCs, and restoration of miR-509-5p may be a promising strategy to treat PAH.

MiR-140-5p exerts a protective function in pregnancy-induced hypertension via mediating TGF-β/Smad signaling pathway

Animal experiments showed that PIH rats had increased mean arterial pressure (MAP), systolic blood pressure (SBP), and diastolic blood pressure (DBP), but decreased litter size, number of viable fetuses, fetal weight, and placental weight. The higher Flt-1 and lower VEGF was observed in PIH rats with elevated TNF-α and IL-6 levels and decreased IL-10 levels. Treatment with agomiR-140-5p improved regarding the above indicators. Cell experiments demonstrated that miR-140-5p mimic increased cell invasion and migration abilities and decreased the activity of TGF-β/Smad pathway, while TGFBR1 can reverse the role of miR-140-5p mimic in trophoblasts.

Epigenetic Mechanisms as Emerging Therapeutic Targets and Microfluidic Chips Application in Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is a disease that progress over time and is defined as an increase in pulmonary arterial pressure and pulmonary vascular resistance that frequently leads to right-ventricular (RV) failure and death. Epigenetic modifications comprising DNA methylation, histone remodeling, and noncoding RNAs (ncRNAs) have been established to govern chromatin structure and transcriptional responses in various cell types during disease development. However, dysregulation of these epigenetic mechanisms has not yet been explored in detail in the pathology of pulmonary arterial hypertension and its progression with vascular remodeling and right-heart failure (RHF). Targeting epigenetic regulators including histone methylation, acetylation, or miRNAs offers many possible candidates for drug discovery and will no doubt be a tempting area to explore for PAH therapies. This review focuses on studies in epigenetic mechanisms including the writers, the readers, and the erasers of epigenetic marks and targeting epigenetic regulators or modifiers for treatment of PAH and its complications described as RHF. Data analyses from experimental cell models and animal induced PAH models have demonstrated that significant changes in the expression levels of multiple epigenetics modifiers such as HDMs, HDACs, sirtuins (Sirt1 and Sirt3), and BRD4 correlate strongly with proliferation, apoptosis, inflammation, and fibrosis linked to the pathological vascular remodeling during PAH development. The reversible characteristics of protein methylation and acetylation can be applied for exploring small-molecule modulators such as valproic acid (HDAC inhibitor) or resveratrol (Sirt1 activator) in different preclinical models for treatment of diseases including PAH and RHF. This review also presents to the readers the application of microfluidic devices to study sex differences in PAH pathophysiology, as well as for epigenetic analysis.

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.

The role of TGF-β or BMPR2 signaling pathway-related miRNA in pulmonary arterial hypertension and systemic sclerosis

Pulmonary arterial hypertension (PAH) is a severe complication of connective tissue disease (CTD), causing death in systemic sclerosis (SSc). The past decade has yielded many scientific insights into microRNA (miRNAs) in PAH and SSc. This growth of knowledge has well-illustrated the complexity of microRNA (miRNA)-based regulation of gene expression in PAH. However, few miRNA-related SSc-PAH were elucidated. This review firstly discusses the role of transforming growth factor-beta (TGF-β) signaling and bone morphogenetic protein receptor type II (BMPR2) in PAH and SSc. Secondly, the miRNAs relating to TGF-β and BMPR2 signaling pathways in PAH and SSc or merely PAH were subsequently summarized. Finally, future studies might develop early diagnostic biomarkers and target-oriented therapeutic strategies for SSc-PAH and PAH treatment.

An Overview of miRNAs Involved in PASMC Phenotypic Switching in Pulmonary Hypertension

Pulmonary hypertension (PH) is occult, with no distinctive clinical manifestations and a poor prognosis. Pulmonary vascular remodelling is an important pathological feature in which pulmonary artery smooth muscle cells (PASMCs) phenotypic switching plays a crucial role. MicroRNAs (miRNAs) are a class of evolutionarily highly conserved single-stranded small noncoding RNAs. An increasing number of studies have shown that miRNAs play an important role in the occurrence and development of PH by regulating PASMCs phenotypic switching, which is expected to be a potential target for the prevention and treatment of PH. miRNAs such as miR-221, miR-15b, miR-96, miR-24, miR-23a, miR-9, miR-214, and miR-20a can promote PASMCs phenotypic switching, while such as miR-21, miR-132, miR-449, miR-206, miR-124, miR-30c, miR-140, and the miR-17~92 cluster can inhibit it. The article reviews the research progress on growth factor-related miRNAs and hypoxia-related miRNAs that mediate PASMCs phenotypic switching in PH.

The roles of microRNAs played in lung diseases via regulating cell apoptosis

MicroRNAs (miRNAs) are a type of endogenous non-coding short-chain RNA, which plays a crucial role in the regulation of many essential cellular functions, including cellular migration, proliferation, invasion, autophagy, oxidative stress, apoptosis, and differentiation. The lung can be damaged by pathogenic microorganisms, as well as physical or chemical factors. Research has confirmed that miRNAs and lung cell apoptosis can affect the development and progression of several lung diseases. This article reviews the role of miRNAs in the development of lung disease through regulating host cell apoptosis.

LncRNA PAXIP1-AS1 fosters the pathogenesis of pulmonary arterial hypertension via ETS1/WIPF1/RhoA axis

Pulmonary arterial hypertension (PAH) is a life‐threatening disease featured with elevated pulmonary vascular resistance and progressive pulmonary vascular remodelling. It has been demonstrated that lncRNA PAXIP1‐AS1 could influence the transcriptome in PAH. However, the exact molecular mechanism of PAXIP1‐AS1 in PAH pathogenesis remains largely unknown. In this study, in vivo rat PAH model was established by monocrotaline (MCT) induction and hypoxia was used to induce in vitro PAH model using human pulmonary artery smooth muscle cells (hPASMCs). Histological examinations including H&E, Masson's trichrome staining and immunohistochemistry were subjected to evaluate the pathological changes of lung tissues. Expression patterns of PAXIP1‐AS1 and RhoA were assessed using qRT‐PCR and Western blotting, respectively. CCK‐8, BrdU assay and immunofluorescence of Ki67 were performed to measure the cell proliferation. Wound healing and transwell assays were employed to evaluate the capacity of cell migration. Dual‐luciferase reporter assay, co‐immunoprecipitation, RIP and CHIP assays were employed to verify the PAXIP1‐AS1/ETS1/WIPF1/RhoA regulatory network. It was found that the expression of PAXIP1‐AS1 and RhoA was remarkably higher in both lung tissues and serum of MCT‐induced PAH rats, as well as in hypoxia‐induced hPASMCs. PAXIP1‐AS1 knockdown remarkably suppressed hypoxia‐induced cell viability and migration of hPASMCs. PAXIP1‐AS1 positively regulated WIPF1 via recruiting transcriptional factor ETS1, of which knockdown reversed PAXIP1‐AS1‐mediated biological functions. Co‐immunoprecipitation validated the WIPF1/RhoA interaction. In vivo experiments further revealed the role of PAXIP1‐AS1 in PAH pathogenesis. In summary, lncRNA PAXIP1‐AS1 promoted cell viability and migration of hPASMCs via ETS1/WIPF1/RhoA, which might provide a potential therapeutic target for PAH treatment.

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.

Different characteristics of mitochondrial dynamics-related miRNAs on the hemodynamics of pulmonary artery hypertension and chronic thromboembolic pulmonary hypertension

BACKGROUND

Mitochondria are dynamic organelles that undergo fission or fusion. These mitochondrial dynamics are reported to be associated with pulmonary hypertension (PH). PH is divided into 5 groups, including pulmonary artery hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTEPH), based on its pathogenesis. However, it is still unknown whether and how miRNAs related to mitochondrial dynamics (MD) affect PAH and CTEPH.

METHODS

We investigated patients who underwent right heart catheterization between October 2016 and January 2019. Out of 34 PH patients, 12 were diagnosed with PAH, and 22 were diagnosed with CTEPH. In addition, there were 30 patients diagnosed with left heart disease. We enrolled the 34 PH patients as the PH group and 30 left heart disease patients as the control group.

RESULTS

Among MD-related miRNAs, the circulating levels of miR-140-3p were higher, and those of miR-485-5p were lower in the PH group than in the control group (p < 0.01), suggesting that miRNAs inducing mitochondrial fission are related to PH. The miR-140-3p levels in the PAH and CTEPH groups were higher than those in the control group (p < 0.01). The levels of miR-140-3p and miR-485-5p in the PAH group correlated with pulmonary vascular resistance (r = 0.582, p = 0.046) and cardiac index (r = -0.36, p = 0.04), respectively. The miR-485-5p levels in the CTEPH group correlated with right atrium pressure (r = -0.456, p = 0.049).

CONCLUSION

MD-related miRNAs levels change to induce fission and are closely related to the hemodynamics of PAH and CTEPH.

Micro-RNA Analysis in Pulmonary Arterial Hypertension: Current Knowledge and Challenges

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The role of miRNAs in PAH is fast expanding, and it is increasingly difficult to identify which molecules have the highest translational potential.

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This review discusses the challenges in miRNA analysis and interpretation in PAH and highlights 4 promising miRNAs in this field.

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Additional pre-clinical studies and clinical trials are urgently needed to bring miRNAs from the bench to the bedside soon.

Pulmonary arterial hypertension (PAH) is a rare, chronic disease of the pulmonary vasculature that is associated with poor outcomes. Its pathogenesis is multifactorial and includes micro-RNA (miRNA) deregulation. The understanding of the role of miRNAs in PAH is expanding quickly, and it is increasingly difficult to identify which miRNAs have the highest translational potential. This review summarizes the current knowledge of miRNA expression in PAH, discusses the challenges in miRNA analysis and interpretation, and highlights 4 promising miRNAs in this field (miR-29, miR-124, miR-140, and miR-204).

miR‑140‑5p inhibits the proliferation of multiple myeloma cells by targeting VEGFA

MicroRNA (miR)-140-5p is associated with the growth and metastasis of various tumor cell types, yet its role in multiple myeloma (MM) remains unclear. Therefore, the present study aimed to investigate the regulatory effect of miR-140-5p on MM. Reverse transcription-quantitative PCR analysis demonstrated that miR-140-5p was downregulated in MM cell lines, particularly in U266 and RPMI 8226 cells. A Cell Counting Kit-8, wound healing and Transwell assays, as well as flow cytometry indicated that a miR-140-5p mimic could suppress cell viability, migration and invasion. In addition, the mimic promoted apoptosis of U266 and RPMI 8226 cells. Western blot data demonstrated that transfection with miR-140-5p mimic significantly reduced the expression levels of Ki-67, cyclin D1, vimentin, Snail, matrix metalloproteinase (MMP)-2 and MMP-3. Moreover, as predicted by TargetScan7.2 and verified by luciferase activity assay, it was demonstrated that vascular endothelial growth factor A (VEGFA) was targeted by miR-140-5p. Further experiments indicated that VEGFA overexpression promoted cell viability, migration and invasion and suppressed apoptosis of MM cells, and that the miR-140-5p mimic partially reversed the effects of VEGFA overexpression. Therefore, miR-140-5p suppressed MM progression by targeting VEGFA. The present findings provide insight into potential therapeutic strategies for the treatment of MM.

Vasoconstrictor Mechanisms in Chronic Hypoxia-Induced Pulmonary Hypertension: Role of Oxidant Signaling

Elevated resistance of pulmonary circulation after chronic hypoxia exposure leads to pulmonary hypertension. Contributing to this pathological process is enhanced pulmonary vasoconstriction through both calcium-dependent and calcium sensitization mechanisms. Reactive oxygen species (ROS), as a result of increased enzymatic production and/or decreased scavenging, participate in augmentation of pulmonary arterial constriction by potentiating calcium influx as well as activation of myofilament sensitization, therefore mediating the development of pulmonary hypertension. Here, we review the effects of chronic hypoxia on sources of ROS within the pulmonary vasculature including NADPH oxidases, mitochondria, uncoupled endothelial nitric oxide synthase, xanthine oxidase, monoamine oxidases and dysfunctional superoxide dismutases. We also summarize the ROS-induced functional alterations of various Ca2+ and K+ channels involved in regulating Ca2+ influx, and of Rho kinase that is responsible for myofilament Ca2+ sensitivity. A variety of antioxidants have been shown to have beneficial therapeutic effects in animal models of pulmonary hypertension, supporting the role of ROS in the development of pulmonary hypertension. A better understanding of the mechanisms by which ROS enhance vasoconstriction will be useful in evaluating the efficacy of antioxidants for the treatment of pulmonary hypertension.

Beyond the genome: challenges and potential for epigenetics-driven therapeutic approaches in pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is a devastating disease of the cardiopulmonary system caused by the narrowing of the pulmonary arteries, leading to increased vascular resistance and pressure. This leads to right ventricle remodeling, dysfunction, and eventually, death. While conventional therapies have largely focused on targeting vasodilation, other pathological features of PAH including aberrant inflammation, mitochondrial dynamics, cell proliferation, and migration have not been well explored. Thus, despite some recent improvements in PAH treatment, the life expectancy and quality of life for patients with PAH remains poor. Showing many similarities to cancers, PAH is characterized by increased pulmonary arterial smooth muscle cell proliferation, decreased apoptotic signaling pathways, and changes in metabolism. The recent successes of therapies targeting epigenetic modifiers for the treatment of cancer has prompted epigenetic research in PAH, revealing many new potential therapeutic targets. In this minireview we discuss the emergence of epigenetic dysregulation in PAH and highlight epigenetic-targeting compounds that may be effective for the treatment of PAH.

miR-140-5p targeted FGF9 and inhibited the cell growth of laryngeal squamous cell carcinoma

Increasing evidence has suggested that microRNAs (miRNAs) play critical roles in the initiation and development of cancers. Here, we found that miR-140-5p was significantly downregulated in both laryngeal squamous cell carcinoma (LSCC) tissues and cell lines. Decreased expression of miR-140-5p was significantly associated with the metastasis of LSCC. Overexpression of miR-140-5p inhibited proliferation and induced apoptosis of LSCC cells. Mechanistically, the fibroblast growth factor 9 (FGF9) was identified as the target of miR-140-5p. miR-140-5p bound the 3′-untranslated region (3′-UTR) of FGF9 and suppressed the expression of FGF9 in LSCC cells. Additionally, the level of FGF9 was upregulated in LSCC tissues and negatively correlated with the expression of miR-140-5p. Restoration of FGF9 attenuated the suppressive role of miR-140-5p in regulating the growth of LSCC cells. Collectively, these results indicated that the tumor suppressive function of miR-140-5p in LSCC was partially exercised by modulating the expression of FGF9.

LncRNA SNHG1 protects SH-SY5Y cells from hypoxic injury through miR-140-5p/Bcl-XL axis

Background: Hypoxic brain injury is one of the major causes of neurodevelopmental impairment and cardiovascular disability. LncRNA SNHG1 works as a critical factor in hypoxic induced injury, however, the potential mechanism is still not known well.Methods: The expression level of small nucleolar RNA host gene 1 (SNHG1) and miR-140-5p was detected by qRT-PCR. The western blot assay was performed to measure the level of Bcl-XL and apoptosis-related proteins. The target relationship between lncRNA SNHG1 and miR-140-5p, as well as miR-140-5p and Bcl-XL was detected by dual luciferase reporter gene assay. Cell apoptosis was assessed using Annexin V/PI staining by flow cytometry. Cell viability was analyzed by MTT assay.Results: Oxygen glucose deprivation (OGD) treatment inhibited SNHG1 and Bcl-XL expression and enhanced miR-140-5p expression. OGD treatment-induced cell viability inhibition, cell apoptosis promotion were partially abrogated when SH-SY5Y cells were transfected with pcDNA3.1-SNHG1 or miR-140-5p inhibitor. Moreover, luciferase reporter assay revealed that lncRNA SNHG1 bound directly to miR-140-5p, and miR-140-5p directly targeted Bcl-XL. The protective effect of SNHG1 overexpressing on cell apoptosis induced by OGD was attenuated after transfected with miR-140-5p mimic or sh-Bcl-XL in SH-SY5Y cells.Conclusion: LncRNA SNHG1-modulated miR-140-5p inhibition regulates Bcl-XL expression, thereby reducing cell apoptosis and recovering cell viability of SH-SY5Y cells. The results in this study provide novel insight into the mechanism of SNHG1 mediated signaling pathway during hypoxic brain injury.

LncRNA PVT1 promotes proliferation and invasion through enhancing Smad3 expression by sponging miR-140-5p in cervical cancer

Background

Cervical cancer is one of the most frequent malignancies among females worldwide. Increasing evidence have indicated the participation of long noncoding RNAs (lncRNAs) in the progression and metastasis of cervical cancer. Our present study was conducted to explore the effects of lncRNA plasmacytoma variant translocation 1 (PVT1) on the progression of cervical cancer and the underlying mechanisms.

Materials and methods

Expressions of PVT1, miR-140-5p and Smad3 in cervical cancer cell lines were detected by qRT-PCR and western blotting. Bioinformatics analysis and luciferase assays were used to elucidate the potential correlations between PVT1, miR-140-5p and Smad3. The roles of PVT1 on the progression of cervical cancer cells were determined by transfecting sh-RNA through series function assays such as colony formation assay, wound healing assay, transwell assay.

Results

PVT1 and Smad3 were upregulated, and miR-140-5p was downregulated in cervical cancer cells. PVT1 could bind directly with miR-140-5p, and Smad3 was a downstream target of miR-140-5p. Inhibition of PVT1 could enhance expression of miR-140-5p, inhibit the expression of Smad3, significantly inhibited the proliferation, migration, invasion in cervical cancer cells. While transfection of miR-140-5p inhibitor could partially reverse the above changes in cervical cancer cells.

Conclusions

The results revealed that PVT1 could promote the proliferation and metastasis via increasing the Smad3 expression by sponging miR-140-5p, which might be a promising prognostic and therapeutic target for cervical cancer.

miR-140-5p regulates the odontoblastic differentiation of dental pulp stem cells via the Wnt1/β-catenin signaling pathway

BACKGROUND

MicroRNAs (miRNAs) play a key role in regulating cell differentiation. In the present study, we aimed to explore the role of miR-140-5p in odontoblastic differentiation of dental pulp stem cells (DPSCs).

METHODS

DPSCs from normal human impacted third molars were isolated and cultured. After overexpression or silencing of miR-140-5p in DPSCs, activity, proliferation, and odontoblastic differentiation of DPSCs were evaluated. The possible target gene of miR-140-5p was verified by luciferase reporter gene assay. Using gene transfection technology, RT-CPR, and Western blot to confirm miR-140-5p regulates the odontoblastic differentiation of DPSCs through Wnt1/β-catenin signaling.

RESULTS

We found the expression of miR-140-5p decreased in the differentiated DPSCs for odontoblastic cells, and at the same time, the expressions of Wnt1 and β-catenin increased. Wnt1 was the target gene of miR-140-5p which was confirmed by luciferase reporter gene system. miR-140-5p overexpression suppressed the expression of Wnt1. miR-140-5p inhibitor could promote the odontoblastic differentiation of DPSCs. miR-140-5p mimic could weaken the odontoblastic differentiation of DPSCs, which could be reversed by the overexpression of Wnt1.

CONCLUSION

Our data demonstrated that miR-140-5p regulates the odontoblastic differentiation of DPSCs via targeting Wnt1/β-catenin signaling. Therefore, miR-140-5p might be a molecular target to regulate the odontoblastic differentiation for the therapeutic agents in dental medicine.

MiR-199a-3p inhibition facilitates cardiomyocyte differentiation of embryonic stem cell through promotion of MEF2C

MicroRNAs (miRNAs) is a small molecule (19-25 nucleotide) noncoding RNA that inhibits the expression of target messenger RNA (mRNA) at the posttranscriptional level as an endogenous regulator. There is an increasing evidence that miR-199a-3p has a significant effect on the development of multiple tumors. However, the specific roles of miR-199a-3p in myocardial differentiation of embryonic stem cell still need to be investigated. Method of the hanging drop was used to build the model of cardiomyocyte differentiation of stem cell and beating rate of embryoid bodies (EBs) was calculated. The levels of intracellular MEF2C, a-MHC, GATA4, Nkx2.5, and cTnT mRNA were measured by real-time quantitative polymerase chain reaction, while the expressions of miR-199a-3p were detected simultaneously. Protein levels of MEF2C, a-MHC, GATA4, Nkx2.5, and cTnT were quantified by western blot analysis. Immunoreactivities of MEF2C and cTnT were analyzed by immunofluorescence. The interaction between miR-199a-3p and its predicted target (3'-untranslated region of MEF2C mRNA) was verified by luciferase assay. MiR-199a-3p levels increased during cardiogenesis. MiR-199a-3p inhibitor increased the beating rate of EBs and promoted expressions of cardiac-specific markers (GATA4, Nkx2.5, cTnT, and a-MHC). Notably, miR-199a-3p inhibition brought upregulation of MEF2C, which is the target of miR-199a-3p that we predicted and verified experimentally. In addition, MEF2C siRNA decreased miR-199a-3p inhibitor promoted EBs beating and attenuated miR-199a-3p inhibitor-induced cTnT and MEF2C expressions. The results above showed that MEF2C was involved in the process of promoting the differentiation of stem cells into cardiac myocytes by miR-199a-3p inhibitors.

Role of RASEF hypermethylation in cigarette smoke-induced pulmonary arterial smooth muscle remodeling

Background

Pulmonary hypertension (PH) is a progressive and fatal disease. While cigarette smoke can change DNA methylation status, the role of such molecular alterations in smoke-associated PH is unclear.

Methods

A PH rat model was developed by exposing animals to cigarette smoke for 3 months. Right ventricular systolic pressure was measured with a right heart catheter. Histological changes (right ventricular hypertrophy index, medial wall thickness in pulmonary arteries (PAs)) and DNMT1 protein levels in rat PAs or primary human PA smooth muscle cells (HPASMCs) exposed to cigarette smoke extract were assessed. Methylation sequencing and MassArray® were used to detect genomic and RASEF promoter methylation status, respectively. After DNMT1 knockdown and cigarette smoke extract exposure, HPASMCs behavior (proliferation, migration) and RASEF methylation status were examined; RASEF mRNA expression was evaluated by real-time-polymerase chain reaction. RASEF overexpression viral vectors were used to assess the impact of RASEF on rat PH and HPASMCs remodeling.

Results

Higher right ventricular systolic pressure, medial wall thickness, and right ventricular hypertrophy index values were observed in the smoking group rats. Smoke exposure increased DNMT1 expression and RASEF methylation levels in rat PAs and HPASMCs. Cigarette smoke extract induced HPASMCs behavioral changes and RASEF hypermethylation followed by silencing, while DNMT1 knockdown markedly inhibited these changes. RASEF overexpression distinctly inhibited PH and HPASMCs remodeling, possibly through phospho-AKT (Ser473), PCNA, and MMP9 downregulation.

Conclusions

Cigarette smoke caused PA remodeling in PH rats related to RASEF hypermethylation. These results expand our understanding of key epigenetic mechanisms in cigarette smoke-associated PH and potentially provide a novel therapeutic target for PH.

Electronic supplementary material

The online version of this article (10.1186/s12931-019-1014-1) contains supplementary material, which is available to authorized users.

Stabilization of p22phox by Hypoxia Promotes Pulmonary Hypertension

AIMS

Hypoxia and reactive oxygen species (ROS) have been shown to play a role in the pathogenesis of pulmonary hypertension (PH), a potentially fatal disorder characterized by pulmonary vascular remodeling, elevated pulmonary arterial pressure, and right ventricular hypertrophy. However, how they are linked in the context of PH is not completely understood. We, therefore, investigated the role of the NADPH oxidase subunit p22phox in the response to hypoxia both in vitro and in vivo.

RESULTS

We found that hypoxia decreased ubiquitinylation and proteasomal degradation of p22phox dependent on prolyl hydroxylases (PHDs) and the E3 ubiquitin ligase protein von Hippel Lindau (pVHL), which resulted in p22phox stabilization and accumulation. p22phox promoted vascular proliferation, migration, and angiogenesis under normoxia and hypoxia. Increased levels of p22phox were also detected in lungs and hearts from mice with hypoxia-induced PH. Mice harboring a point mutation (Y121H) in the p22phox gene, which resulted in decreased p22phox stability and subsequent loss of this protein, were protected against hypoxia-induced PH. Mechanistically, p22phox contributed to ROS generation under normoxia, hypoxia, and hypoxia/reoxygenation. p22phox increased the levels and activity of HIF1α, the major cellular regulator of hypoxia adaptation, under normoxia and hypoxia, possibly by decreasing the levels of the PHD cofactors ascorbate and iron(II), and it contributed to the downregulation of the tumor suppressor miR-140 by hypoxia.

INNOVATION

These data identify p22phox as an important regulator of the hypoxia response both in vitro and in vivo.

CONCLUSION

p22phox-dependent NADPH oxidases contribute to the pathophysiology of PH induced by hypoxia.

MicroRNA-140-5p targeting tumor necrosis factor-α prevents pulmonary arterial hypertension

BACKGROUND

Pulmonary arterial hypertension (PAH) is characterized by the apoptosis resistance and hyperproliferation of pulmonary artery smooth muscle cells (PASMCs). Its pathogenesis has not been revealed. Here, we carried out experiments to investigate the functions of miR-140-5p and tumor necrosis factor-α (TNF-α).

METHODS

We selected GSE703 from Gene Expression Omnibus (GEO) Database to conduct microarray analysis using R software and Gene Set Enrichment Analysis (GSEA). Combing bioinformatics results, the upregulation of miR-140-5p inhibited PAH progression through targeting TNF-α. RNA expression was measured by quantitative real-time polymerase chain reaction (RT-qPCR) and protein level was measured by western blot analysis and enzyme-linked immunosorbent assays (ELISA). We conducted monocrotaline (MCT) injection to rats to form PAH animal models. The lung tissues were observed by hematoxylin-eosin (HE) staining and Sirius red-picric acid staining. Right ventricular systolic pressure (RVSP) and the ratio of right ventricle (RV)-to-left ventricle (LV) plus septum (S) weight (RV/[LV + S]) were measured in MCT-induced animal models. Overexpression of miR-140-5p and TNF-α were utilized to research the proliferation, migration, and phenotypic variation of hypoxia-mediated PASMCs. The binding between miR-140-5p and TNF-α 3'-untranslated region (3'-UTR) was confirmed via luciferase reporter assay.

RESULTS

Downregulation of miR-140-5p and upregulation of TNF-α were observed in PAH rat model and hypoxia-mediated PASMCs. And we proved that overexpression of miR-140-5p could suppress the proliferation, migration, and phenotypic variation of PASMCs, therefore inhibiting PAH pathogenesis. Luciferase assay verified that miR-140-5p targeted TNF-α directly. A converse correlation was also shown between miR-140-5p and TNF-α in PASMCs.

CONCLUSIONS

miR-140-5p and TNF-α are important regulators in PAH pathology and may serve as a therapeutic target for PAH.

Insights on the epigenetic mechanisms underlying pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH), characterized by localized increased arterial blood pressure in the lungs, is a slow developing long-term disease that can be fatal. PAH is characterized by inflammation, vascular tone imbalance, pathological pulmonary vascular remodeling, and right-sided heart failure. Current treatments for PAH are palliative and development of new therapies is necessary. Recent and relevant studies have demonstrated that epigenetic processes may exert key influences on the pathogenesis of PAH and may be promising therapeutic targets in the prevention and/or cure of this condition. The aim of the present mini-review is to summarize the occurrence of epigenetic-based mechanisms in the context of PAH physiopathology, focusing on the roles of DNA methylation, histone post-translational modifications and non-coding RNAs. We also discuss the potential of epigenetic-based therapies for PAH.

Upregulation of miRNA-140-5p inhibits inflammatory cytokines in acute lung injury through the MyD88/NF-κB signaling pathway by targeting TLR4

The present study was designed to determine the effect of miR-140-5p on acute lung injury (ALI) and the associated inflammation induced. As a result, miR-140-5p expression in mice with ALI was suppressed when compared with the normal group. Downregulation of miR-140-5p increased the levels of inflammatory factors induced by ALI [including tumor necrosis factor-α, interleukin (IL)-1β, IL-6 and myeloperoxidase] in an in vitro model of human lung A549 cells. Downregulation of miR-140-5p also induced the protein expression of Toll-like receptor 4 (TLR4), myeloid differentiation primary response 88 (MyD88) and nuclear factor (NF)-κB in an in vitro model. Overexpression of miR-140-5p reduced the levels of inflammation in the in vitro model of ALI via the suppression of the TLR4/MyD88/NF-κB signaling pathway. The inhibition of TLR4 using a TLR4 inhibitor reduced the proinflammation effects of anti-miR-140-5p in the in vitro model of ALI. The NF-κB inhibitor also inhibited the proinflammation effects of anti-miR-140-5p in the in vitro model of ALI. Overall, the results of the present study indicated that miR-140-5p inhibited ALI-induced inflammation via the TLR4/MyD88/NF-κB signaling pathway.

miR-140-5p aggravates hypoxia-induced cell injury via regulating MLK3 in H9c2 cells

Myocardial infarction (MI) is an important cause of cardiovascular disease. microRNAs (miRNAs) have been indicated as pivotal regulators in the physiological and pathological processes of heart diseases. The purpose of this study was to investigate the role of miR-140-5p in hypoxia-induced cell injury in H9c2 cells and its underlying mechanism. H9c2 cells were subjected to hypoxia, before which the expression levels of miR-140-5p and MLK3 were overexpressed or knocked down through transient transfection. The efficiency of transfection was verified by qRT-PCR and Western blotting. Cell viability, apoptotic cell rate, and the expression changes of apoptosis-related proteins were determined by trypan blue exclusion, flow cytometry, and Western blotting, respectively. Furthermore, Western blotting was performed to assess the expression levels of core factors related with p38MAPK and JNK signaling pathways. As a result, hypoxia significantly reduced cell viability and increased cell apoptosis in H9c2 cells. miR-140-5p inhibition attenuated cell injury induced by hypoxia in H9c2 cells, while miR-140-5p overexpression expedited the cell injury, as evidenced by the decreased cell viability and enhanced cell apoptosis. Moreover, miR-140-5p promoted the activation of p38MAPK and JNK pathways. miR-140-5p positively modulated the expression of MLK3. ML3 overexpression reversed the regulatory effects of miR-140-5p inhibition on hypoxia-injured H9c2 cells. In conclusion, this study demonstrated that miR-140-5p aggravated hypoxia-induced cell injury partially through up-regulation of MLK3.

Neuroprotection afforded by circadian regulation of intracellular glutathione levels: A key role for miRNAs

Circadian rhythms are approximately 24-h oscillations of physiological and behavioral processes that allow us to adapt to daily environmental cycles. Like many other biological functions, cellular redox status and antioxidative defense systems display circadian rhythmicity. In the central nervous system (CNS), glutathione (GSH) is a critical antioxidant because the CNS is extremely vulnerable to oxidative stress; oxidative stress, in turn, causes several fatal diseases, including neurodegenerative diseases. It has long been known that GSH level shows circadian rhythm, although the mechanism underlying GSH rhythm production has not been well-studied. Several lines of recent evidence indicate that the expression of antioxidant genes involved in GSH homeostasis as well as circadian clock genes are regulated by post-transcriptional regulator microRNA (miRNA), indicating that miRNA plays a key role in generating GSH rhythm. Interestingly, several reports have shown that alterations of miRNA expression as well as circadian rhythm have been known to link with various diseases related to oxidative stress. A growing body of evidence implicates a strong correlation between antioxidative defense, circadian rhythm and miRNA function, therefore, their dysfunctions could cause numerous diseases. It is hoped that continued elucidation of the antioxidative defense systems controlled by novel miRNA regulation under circadian control will advance the development of therapeutics for the diseases caused by oxidative stress.

Endogenous Regulators of the Immune System (sCD100, Malonic Dialdehyde, and Arginase)

Tissue damage in various diseases, hypoxic conditions, and some pathologies are associated with production of endogenous factors such as the soluble form of the surface receptor CD100, malonic dialdehyde, and arginase and their release into circulation. These factors modulate functional state of lymphocytes in the immune system: potentiate activation of B lymphocytes, activate synthesis and secretion of IL-25 and IL-17 cytokines, and suppress proliferative activity of T lymphocytes, thus modulating immunological reactivity of the organism. Reactions of innate and adaptive immunity develop against the background of changed immunological reactivity, which should be taken into account in the development of pathogenetically substantiated therapy.

Prediction of target genes for miR-140-5p in pulmonary arterial hypertension using bioinformatics methods

The expression of microRNA (miR)-140-5p is known to be reduced in both pulmonary arterial hypertension (PAH) patients and monocrotaline-induced PAH models in rat. Identification of target genes for miR-140-5p with bioinformatics analysis may reveal new pathways and connections in PAH. This study aimed to explore downstream target genes and relevant signaling pathways regulated by miR-140-5p to provide theoretical evidences for further researches on role of miR-140-5p in PAH. Multiple downstream target genes and upstream transcription factors (TFs) of miR-140-5p were predicted in the analysis. Gene ontology (GO) enrichment analysis indicated that downstream target genes of miR-140-5p were enriched in many biological processes, such as biological regulation, signal transduction, response to chemical stimulus, stem cell proliferation, cell surface receptor signaling pathways. Kyoto Encyclopedia of Genes and Genome (KEGG) pathway analysis found that downstream target genes were mainly located in Notch, TGF-beta, PI3K/Akt, and Hippo signaling pathway. According to TF-miRNA-mRNA network, the important downstream target genes of miR-140-5p were PPI, TGF-betaR1, smad4, JAG1, ADAM10, FGF9, PDGFRA, VEGFA, LAMC1, TLR4, and CREB. After thoroughly reviewing published literature, we found that 23 target genes and seven signaling pathways were truly inhibited by miR-140-5p in various tissues or cells; most of these verified targets were in accordance with our present prediction. Other predicted targets still need further verification in vivo and in vitro.

CTRP9 regulates hypoxia-mediated human pulmonary artery smooth muscle cell proliferation, apoptosis and migration via TGF-β1/ERK1/2 signaling pathway

Hypoxia is an important risk factor for pulmonary arterial remodeling in pulmonary arterial hypertension (PAH). Vascular remodeling in hypoxia-induced PAH is driven by excessive proliferation and migration of pulmonary arterial smooth muscle cells (PASMCs). The purpose of the present study was to explore the expression of CTRP9 in rats model of hypoxia-induced PAH and investigate the effects of CTRP9 on HPASMCs function in vitro and determine the underlying mechanisms. We established a rat model of hypoxic PAH, which showed a downregulation of CTRP9 expression. In HPASMCs cultured under the condition of hypoxia, treatment with CTRP9 notably restrained cell proliferation responses to hypoxia accompanied with decreased two biomarkers of cell proliferation Ki-67 and PCNA. Meanwhile, CTRP9 strikingly promoted hypoxia-mediated cell apoptosis as reflected by upregulation of Bax and downregulation of Bcl-2, as well as enhanced Caspase 3 activity. Additionally, CTRP9 treatment dramatically prevented the migratory potential by declined the expression of MMP-2 and MMP-9. Moreover treatment with CTRP9 augmented hypoxia-mediated differentiation by elevating the expression level of differentiation markers α-SMA and SM22. Mechanistically, anti-proliferative effects conferred by CTRP9 are mediated through suppression of TGF-β1/ERK1/2 pathway. Collectively, we identified CTRP9 as a novel mediator of PASMC growth in hypoxia-mediated PAH, indicating that CTRP9 in the pulmonary vasculature may be an underlying mechanism in the development of hypoxia-induced PAH. Our study, for the first time, established that CTRP9 plays a protective role of CTRP9 in pulmonary vascular remodeling, pointing to its potential clinical value for patients with PAH.

Long non-coding RNA Unigene56159 promotes epithelial-mesenchymal transition by acting as a ceRNA of miR-140-5p in hepatocellular carcinoma cells

HBV infection has been reported to be closely associated with HCC development; however, the underlying mechanisms are unclear. Emerging evidence has indicated that long non-coding RNAs (lncRNAs) play important regulatory roles in the pathogenesis and progression of cancers. To investigate the important role and mechanism of lncRNAs in the progression of HBV-related HCC, we screened lncRNAs in HBV-positive and HBV-negative HCC tissues. We identified a novel lncRNA, lncRNA-Unigene56159, which is highly expressed in HBV-related HCC tissues, and further analysis showed that this lncRNA was induced by HBV in vitro. Functionally, Unigene56159 significantly promoted cell migration/invasion and epithelial-mesenchymal transition (EMT) in HCC. Mechanistically, Unigene56159 could directly bind to miR-140-5p and effectively act as a competing endogenous RNA (ceRNA) for miR-140-5p to de-repress the expression of the target gene Slug. Collectively, our findings indicate that the Unigene56159/miR-140-5p/Slug axis contributes to HCC cell migration and invasion, which may provide novel insights into the function of lncRNA-driven hepatocarcinogenesis.