Overexpression of MALAT1 Relates to Lung Injury through Sponging miR-425 and Promoting Cell Apoptosis during ARDS

Artesunate alleviates sepsis-induced liver injury by regulating macrophage polarization via the lncRNA MALAT1/PTBP1/IFIH1 axis

BACKGROUND

The present study aimed to explore the regulatory effects of artesunate on macrophage polarization in sepsis.

METHODS

Cell models and mice models were established using lipopolysaccharide (LPS), followed by treatment with various concentrations of artesunate. The phenotype of the macrophages was determined by flow cytometry. RNA immunoprecipitation was used to confirm the binding between MALAT1 and polypyrimidine tract-binding protein 1 (PTBP1), as well as between PTBP1 and interferon-induced helicase C domain-containing protein 1 (IFIH1).

RESULTS

Treatment with artesunate inhibited M1 macrophage polarization in Kupffer cells subjected to LPS stimulation by downregulating MALAT1. Furthermore, MALAT1 abolished the inhibitory effect of artesunate on M1 macrophage polarization by recruiting PTBP1 to promote IFIH. In vivo experiments confirmed that artesunate alleviated septic liver injury by affecting macrophage polarization via MALAT1.

CONCLUSION

The present study showed that artesunate alleviates LPS-induced sepsis in Kupffer cells by regulating macrophage polarization via the lncRNA MALAT1/PTBP1/IFIH1 axis.

Exploring the translational landscape of the long noncoding RNA transcriptome in acute respiratory distress syndrome: it is a long way to the top

Acute respiratory distress syndrome (ARDS) poses a significant and widespread public health challenge. Extensive research conducted in recent decades has considerably improved our understanding of the disease pathophysiology. Nevertheless, ARDS continues to rank among the leading causes of mortality in intensive care units and its management remains a formidable task, primarily due to its remarkable heterogeneity. As a consequence, the syndrome is underdiagnosed, prognostication has important gaps and selection of the appropriate therapeutic approach is laborious. In recent years, the noncoding transcriptome has emerged as a new area of attention for researchers interested in biomarker development. Numerous studies have confirmed the potential of long noncoding RNAs (lncRNAs), transcripts with little or no coding information, as noninvasive tools for diagnosis, prognosis and prediction of the therapeutic response across a broad spectrum of ailments, including respiratory conditions. This article aims to provide a comprehensive overview of lncRNAs with specific emphasis on their role as biomarkers. We review current knowledge on the circulating lncRNAs as potential markers that can be used to enhance decision making in ARDS management. Additionally, we address the primary limitations and outline the steps that will be essential for integration of the use of lncRNAs in clinical laboratories. Our ultimate objective is to provide a framework for the implementation of lncRNAs in the management of ARDS.

Expression pattern of long non-coding RNAs MALAT1 and MEG3 in COVID-19 patients

BACKGROUND

COVID-19 is a novel infectious disease for which no specific treatment exists. It is likely that a combination of genetic and non-genetic factors predispose to it. Expression levels of genes that are involved in the interaction with SARS-CoV-2 or the host response are thought to play a role in disease susceptibility and severity. It is crucial to explore biomarkers for disease severity and outcome. Herein, we studied the expression levels and effects of long non-coding metastasis-associated lung adenocarcinoma transcript 1 (lnc-MALAT1) and long non-coding maternally expressed gene 3 (lnc-MEG3) in COVID-19 patients. The study enrolled 35 hospitalized and 35 non-hospitalized COVID-19 patients, and 35 healthy controls. A chest computed tomography (CT) scan, complete blood count (CBC), ferritin, C-reactive protein (CRP), D-dimer and analysis of lnc-MALAT1 and lnc-MEG3 expression were done.

RESULTS

There was a significant relation between ferritin, CRP, D-dimer levels, oxygen saturation, CT-CORADS score and disease severity. Lnc-MALAT1 was significantly higher but lnc-MEG3 was significantly lower in patients vs. controls, and in hospitalized vs. non-hospitalized patients. Elevated MALAT1 and reduced MEG3 levels were significantly associated with more elevated ferritin, CRP, D-dimer levels, lower oxygen saturation, higher CT-CORADS score and poor survival. Moreover, MALAT1 and MEG3 levels displayed higher sensitivity and specificity as predictors of COVID-19 severity compared with other prognostic biochemical markers such as ferritin, CRP, and D-dimer.

CONCLUSIONS

MALAT1 levels are higher, whereas MEG3 levels are lower in COVID-19 patients. Both are linked to disease severity and mortality and could emerge as predictive biomarkers for COVID-19 severity and therapeutic targets.

Emerging role of long non-coding RNA MALAT1 related signaling pathways in the pathogenesis of lung disease

Long non-coding RNAs (lncRNAs) are endogenously expressed RNAs longer than 200 nt that are not translated into proteins. In general, lncRNAs bind to mRNA, miRNA, DNA, and proteins and regulate gene expression at various cellular and molecular levels, including epigenetics, transcription, post-transcription, translation, and post-translation. LncRNAs play important roles in many biological processes, such as cell proliferation, apoptosis, cell metabolism, angiogenesis, migration, endothelial dysfunction, endothelial-mesenchymal transition, regulation of cell cycle, and cellular differentiation, and have become an important topic of study in genetic research in health and disease due to their close link with the development of various diseases. The exceptional stability, conservation, and abundance of lncRNAs in body fluids, have made them potential biomarkers for a wide range of diseases. LncRNA MALAT1 is one of the best-studied lncRNAs in the pathogenesis of various diseases, including cancers and cardiovascular diseases. A growing body of evidence suggests that aberrant expression of MALAT1 plays a key role in the pathogenesis of lung diseases, including asthma, chronic obstructive pulmonary diseases (COPD), Coronavirus Disease 2019 (COVID-19), acute respiratory distress syndrome (ARDS), lung cancers, and pulmonary hypertension through different mechanisms. Here we discuss the roles and molecular mechanisms of MALAT1 in the pathogenesis of these lung diseases.

Endothelial plasticity across PTEN and Hippo pathways: A complex hormetic rheostat modulated by extracellular vesicles

Vascularization is a multifactorial and spatiotemporally regulated process, essential for cell and tissue survival. Vascular alterations have repercussions on the development and progression of diseases such as cancer, cardiovascular diseases, and diabetes, which are the leading causes of death worldwide. Additionally, vascularization continues to be a challenge for tissue engineering and regenerative medicine. Hence, vascularization is the center of interest for physiology, pathophysiology, and therapeutic processes. Within vascularization, phosphatase and tensin homolog deleted on chromosome 10 (PTEN) and Hippo signaling have pivotal roles in the development and homeostasis of the vascular system. Their suppression is related to several pathologies, including developmental defects and cancer. Non-coding RNAs (ncRNAs) are among the regulators of PTEN and/or Hippo pathways during development and disease. The purpose of this paper is to review and discuss the mechanisms by which exosome-derived ncRNAs modulate endothelial cell plasticity during physiological and pathological angiogenesis, through the regulation of PTEN and Hippo pathways, aiming to establish new perspectives on cellular communication during tumoral and regenerative vascularization.

Long Noncoding RNA: A Novel Insight into the Pathogenesis of Acute Lung Injury

Acute lung injury (ALI) and its severe form, acute respiratory distress syndrome (ARDS), represent an acute stage of lung inflammation where the alveolar epithelium loses its functionality. ALI has a devastating impact on the population as it not only has a high rate of incidence, but also has high rates of morbidity and mortality. Due to the involvement of multiple factors, the pathogenesis of ALI is complex and is not fully understood yet. Long noncoding RNAs (lncRNAs) are a group of non-protein-coding transcripts longer than 200 nucleotides. Growing evidence has shown that lncRNAs have a decisive role in the pathogenesis of ALI. LncRNAs can either promote or hinder the development of ALI in various cell types in the lungs. Mechanistically, current studies have found that lncRNAs play crucial roles in the pathogenesis of ALI via the regulation of small RNAs (e.g., microRNAs) or downstream proteins. Undoubtedly, lncRNAs not only have the potential to reveal the underlying mechanisms of ALI pathogenesis but also serve as diagnostic and therapeutic targets for the therapy of ALI.

Focus on long non-coding RNA MALAT1: Insights into acute and chronic lung diseases

Acute lung injury (ALI) is a pulmonary illness with a high burden of morbidity and mortality around the world. Chronic lung diseases also represent life-threatening situations. Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) is a type of long non-coding RNA (lncRNA) and is highly abundant in lung tissues. MALAT1 can function as a competitive endogenous RNA (ceRNA) to impair the microRNA (miRNA) inhibition on targeted messenger RNAs (mRNAs). In this review, we summarized that MALAT1 mainly participates in pulmonary cell biology and lung inflammation. Therefore, MALAT1 can positively or negatively regulate ALI and chronic lung diseases (e.g., chronic obstructive pulmonary disease (COPD), bronchopulmonary dysplasia (BPD), pulmonary fibrosis, asthma, and pulmonary hypertension (PH)). Besides, we also found a MALAT1-miRNA-mRNA ceRNA regulatory network in acute and chronic lung diseases. Through this review, we hope to cast light on the regulatory mechanisms of MALAT1 in ALI and chronic lung disease and provide a promising approach for lung disease treatment.

PTEN: An Emerging Potential Target for Therapeutic Intervention in Respiratory Diseases

Phosphatase and tensin homolog deleted on chromosome 10 (PTEN) is a potent tumor suppressor that regulates several key cellular processes, including proliferation, survival, genomic integrity, migration, and invasion, via PI3K-dependent and independent mechanisms. A subtle decrease in PTEN levels or catalytic activity is implicated not only in cancer but also in a wide spectrum of other diseases, including various respiratory diseases. A systemic overview of the advances in the molecular and cellular mechanisms of PTEN involved in the initiation and progression of respiratory diseases may offer novel targets for the development of effective therapeutics for the treatment of respiratory diseases. In the present review, we highlight the novel findings emerging from current research on the role of PTEN expression and regulation in airway pathological conditions such as asthma/allergic airway inflammation, pulmonary hypertension (PAH), chronic obstructive pulmonary disease (COPD), idiopathic pulmonary fibrosis (IPF), and other acute lung injuries (ALI). Moreover, we discuss the clinical implications of PTEN alteration and recently suggested therapeutic possibilities for restoration of PTEN expression and function in respiratory diseases.

Extracellular Vesicles, New Players in Sepsis and Acute Respiratory Distress Syndrome

Sepsis refers to a complex syndrome associated with physiological, pathological, and biochemical abnormalities resulted from infection. Sepsis is the major cause of acute respiratory distress syndrome (ARDS). Extracellular vesicles (EVs) are serving as new messengers to mediate cell-cell communication in vivo. Non-coding RNAs, proteins and metabolites encapsulated by EVs could result in either pro-inflammatory or anti-inflammatory effects in the recipient cells. Pathogens or host cells derived EVs play an important role in pathogens infection during the occurrence and development of sepsis and ARDS. Additionally, we summarize the potential application for EVs in diagnosis, prevention and treatment for sepsis and ARDS.

The lncRNAs/miR-30e/CHI3L1 Axis Is Dysregulated in Systemic Sclerosis

Systemic sclerosis (SSc) is an autoimmune disease with completely undefined etiology and treatment difficulties. The expression of both protein coding and non-coding RNAs is dysregulated during disease development. We aimed to examine a possible regulatory axis implemented in the control of chitinase-3 like protein 1 (CHI3L1) or YKL-40, an inflammation-associated glycoprotein, shown to be elevated in SSc. A panel of seven miRNAs and three lncRNAs potentially involved in the control of CHI3L1 were selected on the basis of in silico analysis. TagMan assay was used to evaluate the expression levels of miRNAs and RT-qPCR for lncRNAs in white blood cells (WBCs) and plasma from SSc patients and healthy controls. Among the eight screened miRNAs, miR-30e-5p (p = 0.04) and miR-30a-5p (p = 0.01) were significantly downregulated in WBCs and plasma of SSc patients, respectively. On the contrary, the expression of the metastasis associated lung adenocarcinoma transcript 1 (MALAT1) (p = 0.044) and the Nuclear enriched abundant transcript 1 (NEAT1) (p = 0.008) in WBCs was upregulated compared to the controls. Increased levels of MALAT1 and NEAT1 could be associated with the downregulation of miR-30e-5p and miR-30a-5p expression in WBCs and plasma. We present novel data on the involvement of a possible regulatory axis lncRNAs/miR-30e/CHI3L1 in SSc and hypothesize that MALAT1 and NEAT1 could act as miR-30e-5p and miR-30a-5p decoys. This may be a reason for the increased serum levels of CHI3L1 in SSc patients.

The expression profile of lung long non-coding RNAs and mRNAs in a mouse model of smoke inhalation injury

To study the potential expression of lung long non-coding RNAs (lncRNAs) and mRNAs during smoke inhalation injury (SII), using a SII mouse model that we created in our previous work. Microarray was used to investigate the lncRNAs and mRNAs profiles. A bioinformatics analysis was performed. Changes in the top 10 down-regulated and 10 up-regulated lncRNAs were validated using Quantitative Reverse Transcription-PCR (RT-qPCR). The acute lung injury (ALI) mouse model was successfully induced by smoke inhalation, as confirmed by the aberrantly modified cell numbers of red blood cells and neutrophils counts, increased levels of TNF-α, IL-1β, Bax, caspase-7, caspase-3, and decreased Bcl-2 content in lung tissues. When compared to the control mice, 577 lncRNAs and 517 mRNAs were found to be aberrantly expressed in the SII mice. According to the Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses, the altered mRNAs were enriched in acute-phase response, oxidoreductase activity, oxidation-reduction process, glutathione metabolism, the wnt signaling pathway, and ferroptosis. A lncRNA-related competitive endogenous RNA (ceRNA) network, including 383 lncRNAs, 318 MicroRNAs (miRNAs), and 421 mRNAs specific to SII, was established. The changes in NONMMUT026843.2, NONMMUT065071.2, ENSMUST00000235858.1, NONMMUT131395.1, NONMMUT122516.1, NONMMUT057916.2, and NONMMUT013388.2 in the lung matched the microarray results. Our findings help to provide a more comprehensive understanding of the pathogenesis of SII as well as new insights into potential therapeutic targets.

Long non-coding RNAs (lncRNAs) NEAT1 and MALAT1 are differentially expressed in severe COVID-19 patients: An integrated single-cell analysis

Hyperactive and damaging inflammation is a hallmark of severe rather than mild Coronavirus disease 2019 (COVID-19). To uncover key inflammatory differentiators between severe and mild COVID-19, we applied an unbiased single-cell transcriptomic analysis. We integrated two single-cell RNA-seq datasets with COVID-19 patient samples, one that sequenced bronchoalveolar lavage (BAL) cells and one that sequenced peripheral blood mononuclear cells (PBMCs). The combined cell population was then analyzed with a focus on genes associated with disease severity. The immunomodulatory long non-coding RNAs (lncRNAs) NEAT1 and MALAT1 were highly differentially expressed between mild and severe patients in multiple cell types. Within those same cell types, the concurrent detection of other severity-associated genes involved in cellular stress response and apoptosis regulation suggests that the pro-inflammatory functions of these lncRNAs may foster cell stress and damage. Thus, NEAT1 and MALAT1 are potential components of immune dysregulation in COVID-19 that may provide targets for severity related diagnostic measures or therapy.

Resveratrol inhibits cell apoptosis by suppressing long noncoding RNA (lncRNA) XLOC_014869 during lipopolysaccharide-induced acute lung injury in rats

Background

Acute lung injury (ALI) is a common clinical complication with a high mortality rate. Resveratrol (Res) has been shown to protect against ALI, but the role of long noncoding RNAs (lncRNAs) in this process is still unclear.

Methods

Male rats (n=20) aged 7–8 weeks were randomly divided into four groups: control, lipopolysaccharide (LPS), LPS + Res, and LPS + dexamethasone (Dexa). Intragastric administration of Res (0.5 mg/kg) or Dexa (1.5 mg/kg) was performed 1 h before intraperitoneal injection of LPS (5 mg/kg). Lung tissue, serum, and bronchoalveolar lavage fluid were sampled 6 h after LPS treatment for inflammatory factor detection, pathological detection, lncRNA sequencing and bioinformatical analysis, and TdT-mediated dUTP Nick-End Labeling. Quantitative real time polymerase chain reaction and western blotting were used to verify the sequencing results. LPS, Res, and RNA interference were used in rat alveolar epithelial cells experiments to confirm the protective of Res/lncRNA against ALI.

Results

Res pretreatment inhibited lung injury and the increase of inflammatory cytokines induced by LPS. The differentially expressed lncRNAs and mRNAs (P<0.05 and |fold change| >2) were mainly involved in the signaling pathway of immunity, infection, signaling molecules and interactions. Among the lncRNAs and mRNAs, 26 mRNAs and 23 lncRNAs had high levels in lungs treated with LPS but decreased with Res, and 17 mRNAs and 27 lncRNAs were at lower levels in lungs treated with LPS but increased with Res. lncRNA and adjacent mRNA analysis showed that lncRNAs XLOC_014869 and the adjacent gene Fos, and the possible downstream genes Jun and Faslg were increased by LPS, but these changes were attenuated by Res. Pretreatment with Res reduced LPS-induced lung tissue apoptosis. Similarly, Res treatment and knockdown of lncRNA XLOC_014869 reduced LPS-induced apoptosis and the levels of Fos, c-Jun, and Fas-L.

Conclusions

Res can inhibit the increase of lncRNAs XLOC_014869 caused by LPS stimulation and inhibit lung cell apoptosis. These effects may be due to lncRNA XLOC_014869 mediation of the pro-apoptotic factors (Fos, c-Jun, and Fas-L).

lncRNA NEAT1 aggravates sepsis-induced lung injury by regulating the miR-27a/PTEN axis

Sepsis is an acute inflammatory reaction and a cause of acute respiratory distress syndrome (ARDS). In the present study, we explored the roles and underlying mechanism of the lncRNA Nuclear enriched abundant transcript 1 (NEAT1) in ARDS. The expression levels of genes, proteins and pro-inflammatory cytokines in patients with ARDS, LPS-stimulated cells and septic mouse models were quantified using qPCR, western blotting and ELISA assays, respectively. The molecular targeting relationship was validated by conducting a dual-luciferase reporter assay. Cell proliferation was assessed using the Cell Counting Kit-8 (CCK-8) assay. The cell cycle phase was determined by flow cytometry assay. The expression levels of NEAT1 and pro-inflammatory cytokines were higher in patients with ARDS and septic models than in controls. Knockdown of NEAT1 significantly increased cell proliferation and cycle progression and prolonged mouse survival in vitro and in vivo. Mechanistically, miR-27a was identified as a downstream target of NEAT1 and directly inhibited PTEN expression. Further rescue experiments revealed that inhibition of miR-27a impeded the promoting effects of NEAT1 silence on cell proliferation and cycle progression, whereas inhibition of PTEN markedly weakened the inhibitory effects of NEAT1 overexpression on cell proliferation and cycle progression. Altogether, our study revealed that NEAT1 plays a promoting role in the progression of ARDS via the NEAT1/miR-27a/PTEN regulatory network, providing new insight into the pathologic mechanism behind ARDS.

Long non-coding RNA (lncRNA): A potential therapeutic target in acute lung injury

Acute Lung Injury (ALI) and its severe form Acute Respiratory Distress Syndrome (ARDS) are the major cause of ICU death worldwide. ALI/ARDS is characterized by severe hypoxemia and inflammation that leads to poor lung compliance. Despite many advances in understanding and management, ALI/ARDS is still causing significant morbidity and mortality. Long non-coding RNA (lncRNA) is a fast-growing topic in lung inflammation and injury. lncRNA is a class of non-coding RNA having a length of more than 200 nucleotides. It has been a center of research for understanding the pathophysiology of various diseases in the past few years. Multiple studies have shown that lncRNAs are abundant in acute lung injury/injuries in mouse models and cell lines. By targeting these long non-coding RNAs, many investigators have demonstrated the alleviation of ALI in various mouse models. Therefore, lncRNAs show great promise as a therapeutic target in ALI. This review provides the current state of knowledge about the relationship between lncRNAs in various biological processes in acute lung injury and its use as a potential therapeutic target.

Long non-coding RNA review and implications in acute lung inflammation

Acute lung inflammatory diseases severely affect the patients' recovery and outcomes worldwide. Unregulated acute inflammatory response is fundamentally central to acute lung inflammation including acute lung injury (ALI) and acute respiratory distress syndrome (ARDS). To limit the potentially deleterious effects of acute lung inflammation, complex transcriptional and posttranscriptional regulatory networks have been explored, which often involves long noncoding RNAs (lncRNA). LncRNAs are RNAs that longer than 200 nucleotides, functioning as scaffolds or decoys in the cytoplasm or nucleus. By now, lncRNAs have been found to join in all major cellular processes including cell proliferation, metabolism, stress response or death. Extensive advance over the last decade furthermore indicated a fundamental role of lncRNAs in acute lung inflammation. This article reviews and summarizes the current knowledge on lncRNA in acute lung inflammatory response.

Comprehensive Analysis of the Profiles of Differentially Expressed mRNAs, lncRNAs, and circRNAs in Phosgene-Induced Acute Lung Injury

Phosgene exposure can cause acute lung injury (ALI), for which there is no currently available effective treatment. Mesenchymal stem cells (MSCs) which have been proven to have therapeutic potential and be helpful in the treatment of various diseases, but the mechanisms underlying the function of MSCs against phosgene-induced ALI are still poorly explored. In this study, we compared the expression profiles of mRNAs, lncRNAs, and circRNAs in the lung tissues from rats of three groups—air control (group A), phosgene-exposed (group B), and phosgene + MSCs (group C). The results showed that 389 mRNAs, 198 lncRNAs, and 56 circRNAs were differently expressed between groups A and B; 130 mRNAs, 107 lncRNAs, and 35 circRNAs between groups A and C; and 41 mRNAs, 88 lncRNAs, and 18 circRNAs between groups B and C. GO and KEGG analyses indicated that the differentially expressed RNAs were mainly involved in signal transduction, immune system processes, and cancers. In addition, we used a database to predict target microRNAs (miRNAs) interacting with circRNAs and the R network software package to construct a circRNA-targeted miRNA gene network map. Our study showed new insights into changes in the RNA expression in ALI, contributing to explore the mechanisms underlying the therapeutic potential of MSCs in phosgene-induced ALI.

Effect and mechanism of phospholipid scramblase 4 (PLSCR4) on lipopolysaccharide (LPS)-induced injury to human pulmonary microvascular endothelial cells

Background

Previous experiments revealed phospholipid scramblase 4 (PLSCR4) mRNA to be significantly increased in a lipopolysaccharide (LPS)-induced acute respiratory distress syndrome (ARDS) model of human pulmonary microvascular endothelial cells (HPMECs); however, the effect of PLSCR4 and its mechanism have not been reported to date. The PLSCR family is thought to mediate the transmembrane movement of phospholipids (PS), and has been found to be involved in pyroptosis through combing with gasdermin D (GSDMD). We therefore speculated that PLSCR4 may contribute to cell death via pyroptosis.

Methods

To investigate the effect and mechanism of PLSCR4 in ARDS, we constructed an in vitro model of LPS-induced ARDS in HPMECs transfected with PLSCR4 small interfering RNA (siRNA) or scramble siRNA (sc siRNA). After 4 h of LPS stimulation, western blotting, immunoprecipitation, enzyme-linked immunosorbent assay (ELISA), tracer flux assays, and fluorescence assays were used to study the relationship between PLSCR4 and pyroptosis with regards to their impact on ARDS. We also established an ARDS mouse model which was pretreated with a liquid complex of PLSCR4 siRNA/sc siRNA-lipofectamine 2000 through the fundus venous plexus. Finally, we used DNA pull-down and protein profiling to study the potential transcription factor of PLSCR4.

Results

It was found that when the expression of PLSCR4 was elevated, the concentration of interleukin 1 beta (IL-1β) and IL-18 decreased, along with barrier damage (P<0.05). Furthermore, HPMEC injury was reduced with more distribution of PS and N-terminal cleavage product (GSDMD-NT) of GSDMD on the external side of cell membrane. However, the pyroptosis-relevant proteins of GSDMD and caspase-1 were not obviously changed (P<0.05); we further found that when PLSCR4 was depressed, the lung injury was aggravated in the mice. In the DNA pull-down assay, P62280 remarkably increased, which suggested that P62280 might be the transcription factor for PLSCR4.

Conclusions

PLSCR4 alleviated pyroptosis by transporting PS to the outside of the membrane, blocking the formation of pyroptosis pores composed of GSDMD. Moreover, P62280 might be the transcription factor of PLSCR4. These insults may provide useful insights into the clinical treatment of ARDS.

Bone marrow mesenchymal stem cell-derived exosomes alleviate hyperoxia-induced lung injury via the manipulation of microRNA-425

BACKGROUND

Hyperoxia-induced lung injury (HILI) is an acute lung injury (LI) induced by extended periods of exposure to hyperoxia. Alleviating LI by bone marrow mesenchymal stem cell-derived exosomes (BMSCs-Exos) and microRNAs (miRs) has been previously reported. This study is devised to probe the interaction between BMSCs-Exos and miR-425 in HILI.

METHODS

Firstly, BMSCs-Exos were isolated and identified. Then, HILI rat models and RLE-6TN cell models were successfully established and treated by BMSCs-Exos. Afterwards, functional assays were conducted to explore cell biological behaviors in models, with miR-425 expression detected. Then, the target relation between miR-425 and PTEN was clarified by luciferase reporter assay. Eventually, expression of PTEN and the PI3K/Akt axis was assessed by Western blotting and qRT-PCR.

RESULTS

BMSCs-Exos promoted miR-425 expression and attenuated HILI and H₂O₂ induced RLE-6TN cell injury as evidence by alleviated lung cell injury, decreased TUNEL-positive cells, induced cell viability and declined apoptosis (all p < 0.05). Besides, when miR-425 was knocked-down, the protective role of BMSCs-Exos in HILI was also reduced (all p < 0.05). miR-425 targeted PTEN mRNA, whose upregulation reversed the protective role of BMSCs-Exos in HILI (all p < 0.05). BMSCs-Exos improved the quenched levels of the PI3K/AKT axis in HILI (all p < 0.05).

CONCLUSION

Our data supported that miR-425 in BMSCs-Exos inhibits HILI by targeting PTEN and upregulating the PI3K/AKT axis. This study may provide personalized interventions for HILI remedy.

Long non-coding RNA MALAT1 exacerbates acute respiratory distress syndrome by upregulating ICAM-1 expression via microRNA-150-5p downregulation

Acute respiratory distress syndrome (ARDS) is a severe form of acute lung injury in which severe inflammatory responses induce cell apoptosis, necrosis, and fibrosis. This study investigated the role of lung adenocarcinoma transcript 1 (MALAT1) in ARDS and the underlying mechanism involved. The expression of MALAT1, microRNA-150-5p (miR-150-5p), and intercellular adhesion molecule-1 (ICAM-1) was determined in ARDS patients and lipopolysaccharide (LPS)-treated human pulmonary microvascular endothelial cells (HPMECs). Next, the interactions among MALAT1, miR-150-5p, and ICAM-1 were explored. Gain- or loss-of-function experiments in HPMECs were employed to determine cell apoptosis and inflammation. Furthermore, a mouse xenograft model of ARDS was established in order to verify the function of MALAT1 in vivo. MALAT1 and ICAM-1 were upregulated, while miR-150-5p was downregulated in both ARDS patients and LPS-treated HPMECs. MALAT1 upregulated ICAM-1 expression by competitively binding to miR-150-5p. MALAT1 silencing or miR-150-5p overexpression was shown to suppress HPMEC apoptosis, decrease the expressions of pro-inflammatory cytokines (IL-6, IL-1β and TNF-α) and E-selectin in HPMECs, as well as alleviated lung injury in nude mice. These findings demonstrated that MALAT1 silencing can potentially suppress HPMEC apoptosis and alleviate lung injury in ARDS via miR-150-5p-targeted ICAM-1, suggestive of a novel therapeutic target for ARDS.