Long non-coding maternally expressed gene 3 regulates cigarette smoke extract-induced apoptosis, inflammation and cytotoxicity by sponging miR-181a-2-3p in 16HBE cells

Long non-coding RNA Small Nucleolar RNA Host Gene 4 ameliorates cigarette smoke-induced proliferation, apoptosis, inflammation, and airway remodeling in alveolar epithelial cells through the modulation of the mitogen-activated protein kinase signaling pathway via the microRNA-409-3p/Four and a Half LIM Domains 1 axis

The long non-coding RNA (lncRNA) Small Nucleolar RNA Host Gene 4 (SNHG4) has been demonstrated to be significantly downregulated in various inflammatory conditions, yet its role in chronic obstructive pulmonary disease (COPD) remains elusive. This study aims to elucidate the biological function of SNHG4 in COPD and to unveil its potential molecular targets. Our findings reveal that both SNHG4 and Four and a Half LIM Domains 1 (FHL1) were markedly downregulated in COPD, whereas microRNA-409-3p (miR-409-3p) was upregulated. Importantly, SNHG4 exhibited a negative correlation with inflammatory markers in patients with COPD, but a positive correlation with forced expiratory volume in 1s percentage (FEV1%). SNHG4 distinguished COPD patients from non-smokers with high sensitivity, specificity, and accuracy. Overexpression of SNHG4 ameliorated cigarette smoke extract (CSE)-mediated inflammation, apoptosis, oxidative stress, and airway remodeling in 16HBE bronchial epithelial cells. These beneficial effects of SNHG4 overexpression were reversed by the overexpression of miR-409-3p or the silencing of FHL1. Mechanistically, SNHG4 competitively bound to miR-409-3p, mediating the expression of FHL1, and consequently improving inflammation, apoptosis, oxidative stress, and airway remodeling in 16HBE cells. Additionally, SNHG4 regulated the miR-409-3p/FHL1 axis to inhibit the activation of the mitogen-activated protein kinase (MAPK) pathway induced by CSE. In a murine model of COPD, knockdown of SNHG4 exacerbated CSE-induced pulmonary inflammation, apoptosis, and oxidative stress. In summary, our data affirm that SNHG4 mitigates pulmonary inflammation, apoptosis, and oxidative damage mediated by COPD through the regulation of the miR-409-3p/FHL1 axis.

Cigarette Smoke Extract-Treated Mouse Airway Epithelial Cells-Derived Exosomal LncRNA MEG3 Promotes M1 Macrophage Polarization and Pyroptosis in Chronic Obstructive Pulmonary Disease by Upregulating TREM-1 via m6A Methylation

Cigarette smoke extract (CSE)-treated mouse airway epithelial cells (MAECs)-derived exosomes accelerate the progression of chronic obstructive pulmonary disease (COPD) by upregulating triggering receptor expressed on myeloid cells 1 (TREM-1); however, the specific mechanism remains unclear. We aimed to explore the potential mechanisms of CSE-treated MAECs-derived exosomes on M1 macrophage polarization and pyroptosis in COPD. In vitro, exosomes were extracted from CSE-treated MAECs, followed by co-culture with macrophages. In vivo, mice exposed to cigarette smoke (CS) to induce COPD, followed by injection or/and intranasal instillation with oe-TREM-1 lentivirus. Lung function and pathological changes were evaluated. CD68+ cell number and the levels of iNOS, TNF-α, IL-1β (M1 macrophage marker), and pyroptosis-related proteins (NOD-like receptor family pyrin domain containing 3, apoptosis-associated speck-like protein containing a caspase-1 recruitment domain, caspase-1, cleaved-caspase-1, gasdermin D [GSDMD], and GSDMD-N) were examined. The expression of maternally expressed gene 3 (MEG3), spleen focus forming virus proviral integration oncogene (SPI1), methyltransferase 3 (METTL3), and TREM-1 was detected and the binding relationships among them were verified. MEG3 increased N6-methyladenosine methylation of TREM-1 by recruiting SPI1 to activate METTL3. Overexpression of TREM-1 or METTL3 negated the alleviative effects of MEG3 inhibition on M1 polarization and pyroptosis. In mice exposed to CS, EXO-CSE further aggravated lung injury, M1 polarization, and pyroptosis, which were reversed by MEG3 inhibition. TREM-1 overexpression negated the palliative effects of MEG3 inhibition on COPD mouse lung injury. Collectively, CSE-treated MAECs-derived exosomal long non-coding RNA MEG3 may expedite M1 macrophage polarization and pyroptosis in COPD via the SPI1/METTL3/TREM-1 axis.

Interaction between long noncoding RNA and microRNA in lung inflammatory diseases

BACKGROUND

Non-coding RNAs (ncRNAs) are a group of RNAs that cannot synthesize proteins, but are critical in gene expression regulation. Long non-coding RNAs (lncRNAs) and microRNAs (miRNAs), the two major family members, are intimately involved in controlling immune response, cell proliferation, apoptosis, differentiation and polarization, and cytokine secretion. Their interactions significantly influence lung inflammatory diseases and could be potential therapeutic targets.

OBJECTIVES

The review aims to elucidate the role of ncRNAs, especially the interactions between lncRNA and miRNA in lung diseases, including acute and chronic lung inflammatory diseases, as well as lung cancer. And provide novel insights into disease mechanisms and potential therapeutic methods.

METHODS

We conducted a comprehensive review of the latest studies on lncRNA and miRNA in lung inflammatory diseases. Our research involved searching through electronic databases like PubMed, Web of Science, and Scopus.

RESULTS

We explain the fundamental characteristics and functions of miRNA and lncRNA, their potential interaction mechanisms, and summarize the newly explorations on the role of lncRNA and miRNA interactions in lung inflammatory diseases.

CONCLUSIONS

Numerous lncRNAs and miRNAs have been found to partipicate in all stages of lung inflammatory diseases. While ncRNA-based therapies have been validated and developed, there remain challenges in developing more stable and effective drugs for clinical use.

LncRNA PVT1 induces apoptosis and inflammatory response of bronchial epithelial cells by regulating miR-30b-5p/BCL2L11 axis in COPD

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is a serious health burden worldwide with high mortality. LncRNA plasmacytoma variant translocation 1 (PVT1) has been illustrated to serve as a biomarker for COPD progression. Nonetheless, its specific functions and mechanisms in COPD are unclarified.

METHODS

Cigarette smoke extract (CSE) was utilized to stimulate 16HBE cells, and cigarette smoke combining with lipopolysaccharide (LPS) was employed to induce COPD in rats. Western blotting and RT-qPCR were utilized for measuring protein and RNA levels. Flow cytometry was implemented for detecting cell apoptosis. Concentrations of inflammatory factors TNF-α and IFN-γ were examined using ELISA. Luciferase reporter assay was utilized for verifying the interaction between molecules. Hematoxylin-eosin staining was performed for histological analysis of rat lung tissues.

RESULTS

PVT1 was highly expressed in CSE-stimulated 16HBE cells and the lungs of COPD rats. PVT1 depletion restored the viability, restrained apoptosis and hindered inflammatory cytokine production in 16HBE cells under CSE treatment and alleviated pathological damages in COPD rats. PVT1 bound to miR-30b-5p and miR-30b-5p targeted BCL2 like 11 (BCL2L11). Overexpressing BCL2L11 offset the above effects mediated by PVT1 in CSE-triggered 16HBE cells.

CONCLUSION

PVT1 enhances apoptosis and inflammation of 16HBE cells under CSE stimulation by modulating miR-30b-5p/BCL2L11 axis.

MEG3 Regulates CSE-Induced Apoptosis by Regulating miR-421/DFFB Signal Axis

Introduction

Chronic obstructive pulmonary disease (COPD) is a common respiratory disease with irreversible and progressive obstruction of airflow. Currently, there are no clinically available treatments to prevent COPD progression. Apoptosis of human lung microvascular endothelial cells (HPMECs) and bronchial epithelial cells (HBECs) is often observed in COPD, but its pathogenesis has not been fully elucidated. LncRNA maternally expressed gene 3 (MEG3) is closely related to CSE-induced apoptosis, but the specific mechanism of MEG3 in COPD is still unknown.

Methods

In the present study, cigarette smoke extract (CSE) is used to treat HPMECs and HBECs. Flow cytometry assay is used to detect the apoptosis of these cells. The expression of MEG3 in CSE-treated HPMECs and HBECs is detected by qRT-PCR. LncBase v.2 is used to predict miRNAs binding to MEG3, and miR-421 is found to bind to MEG3. Dual luciferase report analysis and RNA immunoprecipitation experiment jointly clarified the binding relationship between MEG3 and miR-421.

Results

MiR-421 was downregulated in CSE-treated HPMECs/HBECs, and miR-421 overexpression mitigated CSE-induced apoptosis in these cells. Subsequently, DFFB was found to be directly targeted by miR-421. The overexpression of miR-421 dramatically reduced the expression level of DNA fragmentation factor subunit beta (DFFB). DFFB was found downregulated in CSE-treated HPMECs and HBECs. MEG3 contributed to the apoptosis of HPMECs and HBECs induced by CSE by regulating the miR-421/DFFB axis.

Conclusion

This study presents a new perspective on the diagnosis and treatment of COPD caused by CSE.

LncRNA RP11-521C20.3 Inhibits Cigarette Smoke Extract-Induced Apoptosis in A549 Cells by Targeting BMF Signaling

Objective

LncRNAs are closely correlated with chronic obstructive pulmonary disease (COPD). We investigated the molecular mechanism of lncRNA RP11-521C20.3, which targets the action of the Bcl-2 modifying factor (BMF) signaling pathway in the apoptosis of cigarette smoke extract (CSE)-treated A549 cells.

Methods

Lung tissues derived from cigarette smoke exposed rats (COPD group) and controls were examined using TUNEL assay for apoptotic cells and using immunohistochemistry for BMF expression levels. Overexpression and knockdown of BMF by lentiviral vector transfection were used to explore the role of BMF on the apoptosis of CSE-treated A549 cells. Overexpression and knockdown of RP11-521C20.3 were used to assess the effect of RP11-521C20.3 on the expression levels of BMF and apoptosis in CSE-treated A549 cells. Cell proliferation, mitochondrial morphology, and apoptosis were assessed in A549 cells. Real-time quantitative polymerase chain reactions and Western blotting detected the expression of apoptosis-related molecules.

Results

The number of apoptotic cells and the level of BMF protein were significantly increased in lung tissues of the COPD group compared to the control group. Overexpression of BMF or knockdown of RP11-521C20.3 in CSE-treated A549 cells increased apoptosis, inhibited cell proliferation, and exacerbated mitochondrial damage. There were also increased protein levels of p53, cleaved caspase-3, and cleaved caspase-7, and decreased protein levels of Bcl-2 and survivin. Knockdown of BMF or overexpression of RP11-521C20.3 in CSE-treated A549 cells attenuated apoptosis, promoted cell proliferation, and alleviated mitochondrial damage. Observed effects also included decreased protein levels of p53, cleaved caspase-3, and cleaved caspase-7, and increased protein levels of Bcl-2 and survivin. In CSE-treated A549 cells, overexpression of RP11-521C20.3 suppressed the expression of BMF mRNA and protein.

Conclusion

In CSE-treated A549 cells, BMF promoted apoptosis and RP11-521C20.3 might target the BMF signaling axis to protect CSE-treated A549 cells from apoptosis.

LncRNA ALDB-898 modulates intestinal epithelial cell damage caused by Clostridium perfringens type C in piglet by regulating ssc-miR-122-5p/OCLN signaling

Diarrhea of piglets caused by Clostridium perfringens type C (C. perfringens type C) infection is a global problem afflicting piglet production. Long noncoding RNA (LncRNA) and microRNA (miRNA) have emerged as critical regulators of this pathological process, but the underlying molecular mechanisms remain unclear. In this study, we first observed the expression changes of ALDBSSCG0000000898 (ALDB-898) and ssc-miR-122-5p in infected ileum tissue of piglets with C. perfringens type C, and then used C. perfringens beta2 toxin (CPB2) to induce intestinal porcine epithelial cells (IPEC-J2) to construct an injury model. Cytometry kit 8 (CCK-8), lactate dehydrogenase (LDH), real-time quantitative polymerase chain reaction (RT-qPCR), Western blot, flow cytometry and fluorescein isothiocyanate-dextran 4 (FITC-Dextran 4) flux assays were performed to study the effect of ALDB-898 and ssc-miR-122-5p in apoptosis, inflammation and intestinal barrier damage and inflammatory in IPEC-J2 cells induced by CPB2. In addition, dual-luciferase reporter gene analysis was performed to confirm the relationship between ssc-miR-122-5p and ALDB-898 or ssc-miR-122-5p and occludin (OCLN), respectively. There were lower expression levels of ALDB-898 and OCLN and higher expression levels of ssc-miR-122-5p in diarrhea piglets caused by Clostridium perfringens type C. ALDB-898 and OCLN were significantly decreased and ssc-miR-122-5p was increased in IPEC-J2 after exposure to the CPB2 in a dose- and time-dependent manner. ALDB-898 overexpression mitigated CPB2-induced cell injury by promoting viability, restraining apoptosis, cytotoxicity, and inflammatory response, as well as weakening the destruction of the intestinal barrier. Further mechanisms disclosed that ALDB-898 functioned as a competing endogenous RNA (ceRNA) via binding to ssc-miR-122-5p, and OCLN was a target of ssc-miR-122-5p. Importantly, the ssc-miR-122-5p mimic led to abolishing the protective function of ALDB-898 on CPB2-induced IPEC-J2 cell damage, and the addition of OCLN reversed the negative impact of ssc-miR-122-5p, thereby restoring the protection of ALDB-898. Our data showed that ALDB-898 could enhance the expression of OCLN through competitive binding ssc-miR-122-5p to suppress CPB2-induced damage. The ALDB-898/ssc-miR-122-5p/OCLN signaling may be a candidate therapeutic pathway for diarrhea of piglets.

Role and mechanism of miR-181a-5p in mice with chronic obstructive pulmonary disease by regulating HMGB1 and the NF-κB pathway

Chronic obstructive pulmonary disease (COPD) is a common respiratory disease. This study explored the mechanism of miR-181a-5p in the inflammatory response in COPD mice. COPD mouse models were established by cigarette smoke (CS) exposure following pretreatment with recombinant adeno-associated virus (rAAv)-miR-181a-5p, si-HMGB1 (high mobility group box 1), and NF-κB pathway inhibitor PDTC, respectively. Pathological changes of lung tissues were determined by HE staining. BALF was collected to count total cells, neutrophils and lymphocytes using a Countess II automatic cell counter. Expressions of NE and inflammatory factors (TNF-α, IL-6, IL-8 and IFN-γ) were detected by ELISA. Binding relationship between miR-181a-5p and HMGB1 was predicted on Starbase (http://starbase.sysu.edu.cn/index.php) and validated by dual-luciferase assay. miR-181a-5p expression was detected by RT-qPCR, and expressions of HMGB1, IκBα, p-IκBα were detected by Western blot. The expression level of miR-181a-5p was lower in lung tissues. miR-181a-5p overexpression alleviated inflammatory response and pathological changes of lung tissues in COPD mice, with decreased pulmonary inflammation scores, total cells, neutrophils, and lymphocytes and expressions of NE and inflammatory factors. HMGB1 expression level was increased in COPD mice. miR-181a-5p targeted HMGB1. si-HMGB1 relieved inflammatory responses in COPD mice. NF-κB was activated in COPD mice, evidenced by degraded IκBα and increased p-IκBα level. si-HMGB1 significantly restrained the activation of NF-κB pathway. Briefly, miR-181a-5p targets HMGB1 to inhibit the NF-κB pathway, thus alleviating the inflammatory response in COPD mice.

Multiple time-point assessment of lncRNA MEG3 shows potential to monitor treatment efficacy in rheumatoid arthritis patients

Background: This study explored the clinical role of lncRNA MEG3 in rheumatoid arthritis (RA) management. Materials & methods: Totally, 191 active RA patients were enrolled, and their lncRNA MEG3 expressions in peripheral blood monoclonal cells were detected. Results: LncRNA MEG3 expression was downregulated, and it negatively correlated with lesion joints, inflammation and disease activity in RA patients. Moreover, lncRNA MEG3 expression was increased during treatment; meanwhile its increment correlated with treatment response and remission. Conclusion: LncRNA MEG3 may serve as a potential biomarker for monitoring treatment efficacy in RA management.

XIST promotes apoptosis and the inflammatory response in CSE-stimulated cells via the miR-200c-3p/EGR3 axis

Background

Chronic obstructive pulmonary disease (COPD) is a disease that causes obstructed airways and abnormal inflammatory responses in the lungs. Early growth response 3 (EGR3) has been revealed to play a vital role in the regulation of the inflammatory response in certain diseases. We aimed to explore the role of EGR3 and its upstream mechanism in COPD.

Methods and result

In the present study, 16HBE cells were treated with cigarette smoke extract (CSE) to mimic the inflammatory response in vitro. RT-qPCR revealed that the expression of EGR3 was upregulated in lungs from COPD patients. EGR3 expression in 16HBE cells was increased by CSE treatment. Moreover, flow cytometry analysis and western blot analysis showed that EGR3 downregulation inhibited 16HBE cell apoptosis. EGR3 silencing decreased the protein levels of IL-6, TNF-α, IL-1β and COX2 in CSE-stimulated 16HBE cells. In addition, EGR3 was targeted by microRNA-200c-3p (miR-200c-3p) in 16HBE cells. MiR-200c-3p expression was significantly decreased in lung tissues from COPD patients compared to that in healthy controls. Furthermore, miR-200c-3p bound to lncRNA X-inactive specific transcript (XIST) in 16HBE cells. Additionally, XIST expression was elevated in lung tissues from COPD patients. Rescue assays indicated that EGR3 overexpression counteracted the effects of XIST downregulation on apoptosis and inflammation in CSE-stimulated 16HBE cells.

Conclusion

The XIST/miR-200c-3p/EGR3 axis facilitated apoptosis and inflammation in CSE-stimulated 16HBE cells. These findings may provide novel insight for treating COPD by alleviating lung inflammation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-021-01582-8.

MicroRNA 181a-2-3p Alleviates the Apoptosis of Renal Tubular Epithelial Cells via Targeting GJB2 in Sepsis-Induced Acute Kidney Injury

Acute kidney injury (AKI) is the most common complication of sepsis. MicroRNAs (miRNAs) play important roles in the sepsis-induced AKI. This paper aimed to explore the role of miRNA 181a-2-3p (miR-181a-2-3p) in the sepsis-induced AKI and the underlying mechanism. Our results revealed that miR-181a-2-3p showed low expression levels in patients with sepsis and mouse models undergoing cecal ligation and puncture (CLP). The addition of miR-181a-2-3p antagonists aggravated the sepsis-induced kidney injuries and inflammatory response in CLP mouse models, as suggested by hematoxylin and eosin (H&E) staining and quantitative real-time PCR (qRT-PCR). In addition, miR-181a-2-3p mimic alleviated the lipopolysaccharide (LPS)-induced inflammatory response, along with apoptosis of TCMK-1. Moreover, results from the GSE46955 data set indicated that GJB2 was highly expressed in septic patients but lowly expressed after recovery. Further, the dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay were carried out, which confirmed that GJB2 was a target of miR-181a-2-3p, and overexpression of GJB2 reversed the anti-inflammatory and antiapoptotic effects of miR-181a-2-3p mimic on the LPS-induced sepsis cell models. In conclusion, miR-181a-2-3p alleviates the inflammatory response and cell apoptosis of septic patients and animal models by upregulating GJB2 expression, which may provide a new therapeutic strategy for sepsis.