Long noncoding RNA MALAT1 sponges miR-129-5p to regulate the development of bronchopulmonary dysplasia by increasing the expression of HMGB1

Short-term prognosis of very-preterm infants of ethnic minorities and Han nationality at high altitude: a single-center, retrospective study

OBJECTIVE

We aimed to analyze the perinatal care of very-preterm infants (VPIs) in plateau areas of China and to explore any differences in short-term outcomes between ethnic minorities and Han nationality.

METHODS

VPIs with gestational age (GA) <32 weeks admitted to Qinghai Red Cross Hospital from 1 January 2018 to 31 December 2020 were enrolled. Maternal information, neonatal information, perinatal care and discharge outcomes were retrospectively collected and analyzed.

RESULTS

A total of 302 VPIs were examined, including 143 (47.4%) ethnic minority infants and 159 (52.6%) Han infants. Mothers of ethnic minority infants were significantly younger than those of Han infants (27 y vs. 30 y, p < .001). There were no differences in the incidence of assisted reproduction, multiple pregnancies, maternal hypertension, clinical chorioamnionitis or premature rupture of membranes >18 h between ethnic minority mothers and Han mothers. Lower proportions of cesarean section and incidence of maternal diabetes were observed in ethnic minority mothers than in Han mothers [(9.1 vs.17.6%, p < .05) and (42.7 vs. 57.9%, p < .05, respectively)]. Meanwhile, fewer antenatal steroids were used in minority group than Han group (65.7 vs. 81.1%, p < .05). No significant differences in rates of death, active treatment, necrotizing enterocolitis stage ≥2, moderate-to-severe BPD, and incidence of severe retinopathy of prematurity in VPIs were found between the two groups and in all GA subgroups. Severe neurological injury was significantly less common in the minority newborns than in the Han infants (1.2 vs. 6.1%, p < .05). Compared with Han group, no excess risk of death, death or major morbidity, death despite active treatment, death or major morbidity despite active treatment was observed in ethnic minorities, with or without adjusting for gestational age and prenatal steroids.

CONCLUSIONS

Short-term prognosis of VPIs of ethnic minorities were similar to those of Han nationality.

Circular RNAs expression profiles and bioinformatics analysis in bronchopulmonary dysplasia

BACKGROUND

Bronchopulmonary dysplasia (BPD) has long been considered the most challenging chronic lung disease for neonatologists and researchers due to its complex pathological mechanisms and difficulty in prediction. Growing evidence indicates that BPD is associated with the dysregulation of circular RNAs (circRNAs). Therefore, we aimed to explore the expression profiles of circRNAs and investigate the underlying molecular network associated with BPD.

METHODS

Peripheral blood was collected from very-low-birth-weight (VLBW) infants at 5-8 days of life to extract PBMCs. Microarray analysis and qRT-PCR tests were performed to determine the differentially expressed circRNAs (DEcircRNAs) between BPD and non-BPD VLBW infants. Simultaneous analysis of GSE32472 was conducted to obtain differentially expressed mRNAs (DEmRNA) from BPD infants. The miRNAs were predicted by DEcircRNAs and DEmRNAs of upregulated, respectively, and then screened for overlapping ones. GO and KEGG analysis was performed following construction of the competing endogenous RNA regulatory network (ceRNA) for further investigation.

RESULTS

A total of 65 circRNAs (52 upregulated and 13 downregulated) were identified as DEcircRNAs between the two groups (FC >2.0 and p.adj <0.05). As a result, the ceRNA network was constructed based on three upregulated DEcircRNAs validated by qRT-PCR (hsa_circ_0007054, hsa_circ_0057950, and hsa_circ_0120151). Bioinformatics analysis indicated these DEcircRNAs participated in response to stimulus, IL-1 receptor activation, neutrophil activation, and metabolic pathways.

CONCLUSIONS

In VLBW infants with a high risk for developing BPD, the circRNA expression profiles in PBMCs were significantly altered in the early post-birth period, suggesting immune dysregulation caused by infection and inflammatory response already existed.

Mechanistic studies of MALAT1 in respiratory diseases

Background: The incidence of respiratory diseases and the respiratory disease mortality rate have increased in recent years. Recent studies have shown that long non-coding RNA (lncRNA) MALAT1 is involved in various respiratory diseases. In vascular endothelial and cancer cells, MALAT1 expression triggers various changes such as proinflammatory cytokine expression, cancer cell proliferation and metastasis, and increased endothelial cell permeability. Methods: In this review, we performed a relative concentration index (RCI) analysis of the lncRNA database to assess differences in MALAT1 expression in different cell lines and at different locations in the same cell, and summarize the molecular mechanisms of MALAT1 in the pathophysiology of respiratory diseases and its potential therapeutic application in these conditions. Results: MALAT1 plays an important regulatory role in lncRNA with a wide range of effects in respiratory diseases. The available evidence shows that MALAT1 plays an important role in the regulation of multiple respiratory diseases. Conclusion: MALAT1 is an important regulatory biomarker for respiratory disease. Targeting the regulation MALAT1 could have important applications for the future treatment of respiratory diseases.

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.

Insight Into the Roles of Non-coding RNA in Bronchopulmonary Dysplasia

Bronchopulmonary dysplasia (BPD) is a chronic lung disease most commonly occurring in premature infants, and its pathological manifestations are alveolar hypoplasia and dysregulation of pulmonary vasculature development. The effective treatment for BPD has not yet been established. Non-coding RNAs, including microRNAs and long non-coding RNAs do not encode proteins, but can perform its biological functions at the RNA level. Non-coding RNAs play an important role in the incidence and development of BPD by regulating the expression of genes related to proliferation, apoptosis, angiogenesis, inflammation and other cell activities of alveolar epithelial cells and vascular endothelial cells. Here we summarize the role of non-coding RNAs in BPD, which provides possible molecular marker and therapeutic target for the diagnosis and treatment of BPD.

MALAT1 shuttled by extracellular vesicles promotes M1 polarization of macrophages to induce acute pancreatitis via miR-181a-5p/HMGB1 axis

Acute pancreatitis (AP) is a serious condition carrying a mortality of 25–40%. Extracellular vesicles (EVs) have reported to exert potential functions in cell‐to‐cell communication in diseases such as pancreatitis. Thus, we aimed at investigating the mechanisms by which EV‐encapsulated metastasis‐associated lung adenocarcinoma transcript‐1 (MALAT1) might mediate the M1 polarization of macrophages in AP. Expression patterns of MALAT1, microRNA‐181a‐5p (miR‐181a‐5p) and high‐mobility group box 1 protein (HMGB1) in serum of AP patients were determined. EVs were isolated from serum and pancreatic cells. The binding affinity among miR‐181a‐5p, MALAT1 and HMGB1 was identified. AP cells were co‐cultured with EVs from caerulein‐treated MPC‐83 cells to determine the levels of M1/2 polarization markers and TLR4, NF‐κB and IKBa. Finally, AP mouse models were established to study the effects of EV‐encapsulated MALAT1 on the M1 polarization of macrophages in AP in vivo. MALAT1 was transferred into MPC‐83 cells via EVs, which promoted M1 polarization of macrophages in AP. MALAT1 competitively bound to miR‐181a‐5p, which targeted HMGB1. Moreover, MALAT1 activated the TLR4 signalling pathway by regulating HMGB1. EV‐encapsulated MALAT1 competitively bound to miR‐181a‐5p to upregulate the levels of IL‐6 and TNF‐α by regulating HMGB1 via activation of the TLR4 signalling pathway, thereby inducing M1 polarization of macrophages in AP. In vivo experimental results also confirmed that MALAT1 shuttled by EVs promoted M1 polarization of macrophages in AP via the miR‐181a‐5p/HMGB1/TLR4 axis. Overall, EV‐loaded MALAT1 facilitated M1 polarization of macrophages in AP via miR‐181a‐5p/HMGB1/TLR4, highlighting a potential target for treating AP.

LncRNA-MALAT1, as a biomarker of neonatal BPD, exacerbates the pathogenesis of BPD by targeting miR-206

Neonatal bronchopulmonary dysplasia (BPD) is one of the common causes of premature birth complications, which is caused by lung dysplasia. Long non-coding RNA (LncRNA) has been proved to be related to BPD and other disease processes, but the molecular mechanism of metastasis-related lung adenocarcinoma transcript 1 (MALAT1) in BPD has not been fully understood. This study focused on exploring the clinical and molecular mechanism of MALAT1 in neonatal BPD, aiming to provide new insights for the management of neonatal BPD. In our study, we first found that serum MALAT1 was up-regulated in neonatal BPD and severe BPD. Further, through receiver operating characteristic curve (ROC) analysis, it was found that the area under the curve of MALAT1 for differentiating neonatal BPD from severe BPD was 0.943 and 0.866, respectively. Then, we established BPD models in vivo and in vitro with C57BL/6J mice and BEAS-2B cells, and found that MALAT1 was also highly expressed in them and increased with the induction time of the models. Pathological evaluation confirmed that down-regulating MALAT1 or up-regulating miR-206 might improve the pathological condition of BPD. Obvious inflammatory response, oxidative stress and up-regulated apoptosis were observed in BPD models in vivo and in vitro. However, after MALAT1 knockdown treatment, the above abnormal phenomena were alleviated to varying degrees. Furthermore, we also found that MALAT1 has a targeted relationship with miR-206, and miR-206 is down-regulated in BPD in vivo and in vitro. Down-regulating miR-206 could also eliminate the anti-BPD effect after knocking down MALAT1. The above results indicated that MALAT1 has the potential as a blood biomarker of neonatal BPD, and MALAT1-miR-206 axis mediates BPD process, which may be a new target for neonatal BPD treatment.

The Trinity of cGAS, TLR9, and ALRs Guardians of the Cellular Galaxy Against Host-Derived Self-DNA

The immune system has evolved to protect the host from the pathogens and allergens surrounding their environment. The immune system develops in such a way to recognize self and non-self and develops self-tolerance against self-proteins, nucleic acids, and other larger molecules. However, the broken immunological self-tolerance leads to the development of autoimmune or autoinflammatory diseases. Pattern-recognition receptors (PRRs) are expressed by immunological cells on their cell membrane and in the cytosol. Different Toll-like receptors (TLRs), Nod-like receptors (NLRs) and absent in melanoma-2 (AIM-2)-like receptors (ALRs) forming inflammasomes in the cytosol, RIG (retinoic acid-inducible gene)-1-like receptors (RLRs), and C-type lectin receptors (CLRs) are some of the PRRs. The DNA-sensing receptor cyclic GMP–AMP synthase (cGAS) is another PRR present in the cytosol and the nucleus. The present review describes the role of ALRs (AIM2), TLR9, and cGAS in recognizing the host cell DNA as a potent damage/danger-associated molecular pattern (DAMP), which moves out to the cytosol from its housing organelles (nucleus and mitochondria). The introduction opens with the concept that the immune system has evolved to recognize pathogens, the idea of horror autotoxicus, and its failure due to the emergence of autoimmune diseases (ADs), and the discovery of PRRs revolutionizing immunology. The second section describes the cGAS-STING signaling pathway mediated cytosolic self-DNA recognition, its evolution, characteristics of self-DNAs activating it, and its role in different inflammatory conditions. The third section describes the role of TLR9 in recognizing self-DNA in the endolysosomes during infections depending on the self-DNA characteristics and various inflammatory diseases. The fourth section discusses about AIM2 (an ALR), which also binds cytosolic self-DNA (with 80–300 base pairs or bp) that inhibits cGAS-STING-dependent type 1 IFN generation but induces inflammation and pyroptosis during different inflammatory conditions. Hence, this trinity of PRRs has evolved to recognize self-DNA as a potential DAMP and comes into action to guard the cellular galaxy. However, their dysregulation proves dangerous to the host and leads to several inflammatory conditions, including sterile-inflammatory conditions autoinflammatory and ADs.

LncRNA CASC2 targets CAV1 by competitively binding with microRNA-194-5p to inhibit neonatal lung injury

Long non-coding RNAs (lncRNAs) are vital regulators of different biological processes during bronchopulmonary dysplasia (BPD). This study was conducted to probe the biological roles of lncRNA CASC2 in the pathogenesis of BPD and neonatal lung injury. Firstly, a hyperoxia-induced mouse model with BPD was established. LncRNAs with differential expression in lung tissues of normal and BPD mice were analyzed by microarray. An adenovirus vector overexpressing CASC2 was constructed and its functions on BPD symptoms in model mice were analyzed. Gain- and loss-of function studies of CASC2 were performed in a bronchial epithelial cell line BEAS-2B to determine its role in cell apoptosis and proliferation under normoxic and hyperoxic conditions. The downstream mechanical molecules of lncRNA CASC2 were predicted on bioinformatics systems and confirmed by luciferase assays. The functional interactions among lncRNA CASC2, miR-194-5p, and CAV1 in BPD were determined by rescue experiments. Consequently, lncRNA CASC2 was found to be poorly expressed in BPD mice. Besides, overexpressed CASC2 was found to relieve the symptoms of BPD in neonatal mice and suppress apoptosis as well as promote proliferation in hyperoxia-induced BEAS-2B cells. Importantly, CASC2 was found to regulate CAV1 expression by competitively binding to miR-194-5p and downregulate the activity of the TGF-β1 signaling pathway, thereby suppressing lung injury. Either miR-194-5p upregulation or CAV1 downregulation blocked the roles of CASC2. To sum up, this study evidenced that CASC2 alleviates hyperoxia-induced lung injury in mouse and cell models with the involvement of a miR-194-5p-CAV1 crosstalk and the TGF-β1 inactivation.