Long noncoding RNA MIAT2 alleviates lipopolysaccharide-induced inflammatory damage in WI-38 cells by sponging microRNA-15

SENP1 knockdown-mediated CTCF SUMOylation enhanced its stability and alleviated lipopolysaccharide-evoked inflammatory injury in human lung fibroblasts via regulation of FOXA2 transcription

BACKGROUND

Excessive inflammation is the main cause of treatment failure in neonatal pneumonia (NP). CCCTC-binding factor (CTCF) represents an important node in various inflammatory diseases. In the present study, we tried to clarify the function and underlying molecular mechanism of CTCF on an in vitro cellular model of NP, which was generated by simulating the human lung fibroblast cell line WI-38 with lipopolysaccharide (LPS).

METHODS

The SUMOylation level and protein interaction were verified by Co-immunoprecipitation assay. Cell viability was measured by Cell Counting Kit-8 assay. Inflammatory factors were examined by Enzyme-linked immunosorbent assay. Cell apoptosis was evaluated by TUNEL assay. The binding activity of CTCF to target promoter was tested by chromatin immunoprecipitation and luciferase reporter assay.

RESULTS

LPS treatment restrained cell viability, promoted the production of inflammatory factors, and enhanced cell apoptosis. CTCF overexpression played anti-inflammatory and anti-apoptotic roles. Furthermore, CTCF was modified by SUMOylation with small ubiquitin-like modifier protein 1 (SUMO1). Interfering with sumo-specific protease 1 (SENP1) facilitated CTCF SUMOylation and protein stability, thus suppressing LPS-evoked inflammatory and apoptotic injuries. Moreover, CTCF could bind to the forkhead box protein A2 (FOXA2) promoter region to promote FOXA2 expression. The anti-inflammatory and anti-apoptotic roles of CTCF are associated with FOXA2 activation. In addition, SENP1 knockdown increased FOXA2 expression by enhancing the abundance and binding ability of CTCF.

CONCLUSIONS

SUMOylation of CTCF by SENP1 knockdown enhanced its protein stability and binding ability and it further alleviated LPS-evoked inflammatory injury in human lung fibroblasts by positively regulating FOXA2 transcription.

NRF1 knockdown alleviates lipopolysaccharide-induced pulmonary inflammatory injury by upregulating DKK3 and inhibiting the GSK-3β/β-catenin pathway

Excessive inflammatory injury is the main cause of the incidence of severe neonatal pneumonia (NP) and associated deaths. Although dickkopf-3 (DKK3) exhibits anti-inflammatory activity in numerous pathological processes, its role in NP is still unknown. In this study, human embryonic lung WI-38 and MRC-5 cells were treated with lipopolysaccharide (LPS) to induce inflammatory injury of NP in vitro. The expression of DKK3 was downregulated in LPS-stimulated WI-38 and MRC-5 cells. DKK3 overexpression decreased LPS-induced inhibition of cell viability, and reduced LPS-induced apoptosis of WI-38 and MRC-5 cells. DKK3 overexpression also reduced LPS-induced production of pro-inflammatory factors such as ROS, IL-6, MCP-1, and TNF-α. Nuclear respiratory factors 1 (NRF1) knockdown was found to upregulate DKK3 and inactivate the GSK-3β/β-catenin pathway in LPS-injured WI-38 and MRC-5 cells. NRF1 knockdown also suppressed LPS-induced inhibition on cell viability, repressed LPS-induced apoptosis, and inhibited the accumulation of ROS, IL-6, MCP-1, and TNF-α in LPS-injured WI-38 and MRC-5 cells. DKK3 knockdown or re-activation of the GSK-3β/β-catenin pathway reversed the inhibitory effects of NRF1 knockdown on LPS-induced inflammatory injury. In conclusion, NRF1 knockdown can alleviate LPS-triggered inflammatory injury by regulating DKK3 and the GSK-3β/β-catenin pathway.

The Role of ncRNAs in Cardiac Infarction and Regeneration

Myocardial infarction is the most prevalent cardiovascular disease worldwide, and it is defined as cardiomyocyte cell death due to a lack of oxygen supply. Such a temporary absence of oxygen supply, or ischemia, leads to extensive cardiomyocyte cell death in the affected myocardium. Notably, reactive oxygen species are generated during the reperfusion process, driving a novel wave of cell death. Consequently, the inflammatory process starts, followed by fibrotic scar formation. Limiting inflammation and resolving the fibrotic scar are essential biological processes with respect to providing a favorable environment for cardiac regeneration that is only achieved in a limited number of species. Distinct inductive signals and transcriptional regulatory factors are key components that modulate cardiac injury and regeneration. Over the last decade, the impact of non-coding RNAs has begun to be addressed in many cellular and pathological processes including myocardial infarction and regeneration. Herein, we provide a state-of-the-art review of the current functional role of diverse non-coding RNAs, particularly microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs), in different biological processes involved in cardiac injury as well as in distinct experimental models of cardiac regeneration.

Long noncoding RNA SNHG4 remits lipopolysaccharide-engendered inflammatory lung damage by inhibiting METTL3 - Mediated m6A level of STAT2 mRNA

BACKGROUND

Emerging evidence suggests that long non coding RNA (lncRNA) small nucleolar RNA host gene 4 (SNHG4) has become a new insight into lipopolysaccharide (LPS)-induced microglia inflammation, its role in neonatal pneumonia (NP) remains to be largely unrevealed.

METHODS

RT-qPCR was used to determine the expression of SNHG4 and METTL3 in the serum from NP patients and normal volunteers, as well as in LPS treated-WI-38 cells. The SNHG4 overexpression vector (pcDNA-SNHG4) was transfected into LPS-treated cells. CCK-8, Transwell, annexin V-FITC/PI, ELISA and Western blot assays were used to determine cell proliferation, migration, apoptosis, contents of IL-6, TNF-α, SOD and MDA, as well as the expression levels of NF-κB pathway proteins, respectively. The enrichment of SNHG4 in the METTL3 promoter region was assessed with RIP assay. m⁶A quantitative analysis illustrated the m⁶A level with or without SNHG4 overexpression or METTL3 silencing. Bioinformatics analysis and RIP-PCR were used to predict and validate YTHDF1-mediated m⁶A levels on signal transducer and activator of transcription 2 (STAT2) mRNA in METTL3 inhibited cells. Then rescue experiments were performed to explore effects of SNHG4 and METTL3 or STAT2 on LPS-treated cell functions. Subsequently, in vivo functional experiments were performed to investigate the role of SNHG4 in LPS induced pneumonia in mice.

RESULTS

SNHG4 was downregulated, and METTL3 was upregulated in NP patients and LPS-treated cells. SNHG4 overexpression facilitated cell proliferation, migration and SOD concentration, as well as inhibited cell apoptosis and production of IL-6, TNF-α and MDA, and suppressed the expression of NF-κB pathway proteins. Mechanistically, SNHG4 bound with METTL3 and downregulated METTL3 expression. Besides, total m⁶A level was lower in the SNHG4 overexpressed or METTL3 inhibited cells. METTL3 interference reduced m⁶A levels of STAT2 mRNA, decreased STAT2 mRNA stability and promoted STAT2 translation level. Upregulation of METTL3 or STAT2 reversed the effects of SNHG4 overexpression on LPS-treated cell functions.

CONCLUSIONS

This study reveals that SNHG4 promotes LPS induced inflammation in human lung fibroblasts and mouse lung tissues in vitro and in vivo by inhibiting METTL3-mediated m⁶A level of STAT2 mRNA, which may provide a potential therapeutic mechanism for NP.

LncRNA small nucleolar RNA host gene 16 (SNHG16) silencing protects lipopolysaccharide (LPS)-induced cell injury in human lung fibroblasts WI-38 through acting as miR-141-3p sponge

Long noncoding RNA (LncRNA) small nucleolar RNA host gene 16 (SNHG16) is correlated with cell injuries, including pneumonia. However, its role and mechanism remain vague in pneumonia. The interplay among genes was confirmed by dual-luciferase reporter assay, RNA immunoprecipitation, and RNA pull-down assay. SNHG16 and sushi domain containing 2 (SUSD2) were upregulated, and miRNA (miR)-141-3p was downregulated in the serum of acute pneumonia patients and lipopolysaccharide (LPS)-challenged human lung fibroblasts WI-38. LPS induced apoptosis, autophagy, and inflammatory response in WI-38 cells, which was significantly attenuated by SNHG16 knockdown and/or miR-141-3p overexpression. Notably, both SNHG16 and SUSD2 were identified as target genes of miR-141-3p. Besides, the suppressive role of SNHG16 knockdown in LPS-induced in WI-38 cells was partially abolished by miR-141-3p silencing, and the similar inhibition of miR-141-3p overexpression was further blocked by SUSD2 restoration. In conclusion, knockdown of SNHG16 could alleviate LPS-induced apoptosis, autophagy, and inflammation in WI-38 cells partially though the SNHG16/miR-141-3p/SUSD2 pathway.

MiR-494-3p alleviates acute lung injury through regulating NLRP3 activation by targeting CMPK2

Acute lung injury (ALI) is a severe respiratory disorder with a high rate of mortality, and is characterized by excessive cell apoptosis and inflammation. MicroRNAs (miRNAs) play pivotal roles in ALI. This study examined the biological function of miR-494-3p in cell apoptosis and inflammatory response in ALI. For this, mice were injected with lipopolysaccharide (LPS) to generate an in-vivo model of ALI (ALI mice), and WI-38 cells were stimulated with lipopolysaccharide (LPS) to generate an in-vitro model of ALI. We found that miR-494-3p was significantly downregulated in the ALI mice and in the in-vitro model. Overexpression of miR-494-3p inhibited inflammation and cell apoptosis in the LPS-induced WI-38 cells, and improved the symptoms of lung injury in the ALI mice. We then identified cytidine/uridine monophosphate kinase 2 (CMPK2) as a novel target of miR-494-3p in the WI-38 cells. Furthermore, miR-494-3p suppressed cell apoptosis and the inflammatory response in LPS-treated WI-38 cells through targeting CMPK2. The NLRP3 inflammasome is reportedly responsible for the activation of inflammatory processes. In our study, CMPK2 was confirmed to activate the NLRP3 inflammasome in LPS-treated WI-38 cells. In conclusion, miR-494-3p attenuates ALI through inhibiting cell apoptosis and the inflammatory response by targeting CMPK2, which suggests the value of miR-494-3p as a target for the treatment for ALI.

Gambogic acid protects LPS-induced apoptosis and inflammation in a cell model of neonatal pneumonia through the regulation of TrkA/Akt signaling pathway

Objective

In this work, we investigated the effects of gambogic acid (GA) on lipopolysaccharide (LPS)-induced apoptosis and inflammation in a cell model of neonatal pneumonia.

Method

Human WI-38 cells were maintained in vitro and incubated with various concentrations of GA to examine WI-38 survival. GA-preincubated WI-38 cells were then treated with LPS to investigate the protective effects of GA on LPS-induced death, apoptosis and inflammation. Western blot assay was utilized to analyze the effect of GA on tropomyosin receptor kinase A (TrkA) signaling pathway in LPS-treated WI-38 cells. In addition, human AKT serine/threonine kinase 1 (Akt) gene was knocked down in WI-38 cells to further investigate the associated genetic mechanisms of GA in protecting LPS-induced inflammation and apoptosis.

Results

Pre-incubating WI-38 cells with low and medium concentrations GA protected LPS-induced cell death, apoptosis and inflammatory protein productions of IL-6 and MCP-1. Using western blot assay, it was demonstrated that GA promoted TrkA phosphorylation and Akt activation in LPS-treated WI-38 cells. Knocking down Akt gene in WI-38 cells showed that GA-associated protections against LPS-induced apoptosis and inflammation were significantly reduced.

Conclusions

GA protected LPS-induced apoptosis and inflammation, possibly through the activations of TrkA and Akt signaling pathway. This work may broaden our understanding on the molecular mechanisms of human neonatal pneumonia.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40360-021-00496-9.

LncRNA RP11-248E9.5 and RP11-456D7.1 are Valuable for the Diagnosis of Childhood Pneumonia

Background

Pneumonia is a common infection of the lung parenchyma in children, and early and accurate diagnosis of childhood pneumonia (CP) is important for implementing appropriate preventive and treatment strategies. This study aimed to evaluate the diagnostic value of the combination of long non-coding RNA (lncRNA) RP11-248E9.5, RP11-456D7.1, c-reactive protein (CRP), neutrophil-to-lymphocyte ratio (NLR), and platelet-to-lymphocyte ratio (PLR) in CP.

Patients and Methods

A total of 50 healthy children (HC) and 100 CP patients were enrolled. The serum expression of RP11-248e9.5 and RP11-456d7.1 was detected by qRT-PCR. The white blood cell (WBC), hemoglobin (HB), platelet (PLT), neutrophil, and lymphocyte were analyzed by automated hematology analyzer. The serum levels of CRP and procalcitonin (PCT) were analyzed by automatic biochemical analyzer. The receiver operating characteristic (ROC) curves were applied to evaluate the diagnostic value in CP.

Results

The NLR and PLR, expression of RP11-248E9.5 and RP11-456D7.1, and serum levels of CRP and PCT were significantly higher in the CP group than those in the HC group. Both RP11-248E9.5 (AUC, 0.86; sensitivity, 84%; specificity, 78%) and RP11-456D7.1 (AUC, 0.89; sensitivity, 79%; specificity, 92%) exhibited certain diagnostic value in CP. The diagnostic values of PCT, CRP, NLR and PLR in CP were limited by low sensitivity (≤ 71%). The combination of multiple indicators improved the diagnostic value. The combination of RP11-248E9.5, RP11-456D7.1, CRP, NLR, and PLR had the best diagnostic value in CP (AUC, 0.992; Sensitivity, 0.97; Specificity, 0.99).

Conclusion

The combination of RP11-248E9.5, RP11-456D7.1, CRP, NLR, and PLR was a potential diagnostic strategy for CP.

Knockdown of lncRNA LINC00707 alleviates LPS-induced injury in MRC-5 cells by acting as a ceRNA of miR-223-5p

Pneumonia is a common respiratory disease worldwide. Long noncoding RNAs have been implicated in the pathogenesis of pneumonia. However, the effect and mechanism of long intergenic nonprotein-coding RNA (LINC00707) on pneumonia pathogenesis were still unclear. Lipopolysaccharide (LPS) reduced cell viability and promoted apoptosis and inflammation in MRC-5 cells. LINC00707 was increased, and miR-223-5p was decreased in LPS-treated MRC-5 cells. LINC00707 knockdown relieved LPS-triggered injury in MRC-5 cells. LINC00707 directly interacted with miR-223-5p through acting as a miR-223-5p sponge. Moreover, miR-223-5p mediated the regulation of LINC00707 silencing on LPS-stimulated cytotoxicity in MRC-5 cells. p38 mitogen-activated protein kinases and nuclear factor-κB signaling pathways were modulated by the LINC00707/miR-223-5p axis in LPS-induced MRC-5 cells. Our present study indicated that LINC00707 depletion alleviated LPS-induced injury in MRC-5 cells at least partly by acting as a sponge of miR-223-5p, highlighting a new potential therapeutic avenue for pneumonia treatment.

Silencing lncRNA TUG1 Alleviates LPS-Induced Mouse Hepatocyte Inflammation by Targeting miR-140/TNF

Hepatitis is a major public health problem that increases the risk of liver cirrhosis and liver cancer. Numerous studies have revealed that long non-coding RNAs (lncRNAs) exert essential function in the inflammatory response of multiple organs. Herein, we aimed to explore the effect of lncRNA TUG1 in LPS-induced hepatocyte inflammation response and further illuminate the underlying mechanisms. Mice were intraperitoneally injected with LPS, and the liver inflammation was evaluated. Microarray showed that lncRNA TUG1 was upregulated in LPS-induced hepatocyte inflammation. qRT-PCR and immunofluorescence assay indicated a significant increase of TUG1 in mice with LPS injection. Functional analysis showed that si-TUG1 inhibited LPS-induced inflammation response in mice liver, inhibited apoptosis level, and protected liver function. Then, we knock down TUG1 in normal human hepatocyte AML12. Consistent with in vivo results, si-TUG1 removed the injury of LPS on AML12 cells. Furthermore, TUG1 acted as a sponge of miR-140, and miR-140 directly targeted TNFα (TNF). MiR-140 or si-TNF remitted the beneficial effects of TUG1 on LPS-induced hepatocyte inflammation response both in vitro and in vivo. Our data revealed that deletion of TUG1 protected against LPS-induced hepatocyte inflammation via regulating miR-140/TNF, which might provide new insight for hepatitis treatment.

LncRNA NEAT1 acts as a key regulator of cell apoptosis and inflammatory response by the miR-944/TRIM37 axis in acute lung injury

Acute lung injury (ALI), a common complication of sepsis, is characterized by the impairment and injury of pulmonary function. The nuclear factor kappa-B (NF-κB) pathway is activated in ALI. Tripartite motif-containing 37 (TRIM37) can activate the NF-κB pathway and is closely associated with inflammation. The purpose of our study is to reveal the role of TRIM37 in ALI. The present study revealed that TRIM37 presented high levels in lung tissues of ALI mice, and knockdown of TRIM37 alleviated lipopolysaccharide (LPS)-induced lung injury, inflammatory response, and cell apoptosis in vivo. In addition, knockdown of TRIM37 inhibited the inflammatory response, and cell apoptosis of LPS-treated WI-38 cells. Mechanistically, miR-944 was identified to bind with and negatively regulate TRIM37. Furthermore, NEAT1 was indicated to act as a competitive endogenous RNA to promote TRIM37 expression by sequestering miR-944. Detailly, NEAT1 bound with miR-944, negatively modulated miR-944 expression, and positively modulated TRIM37 expression. The rescue assays suggested that overexpression of TRIM37 rescued the influence of NEAT1 knockdown on cell apoptosis and inflammatory response. Overall, NEAT1 facilitated cell apoptosis and inflammatory response of WI-38 cells by the miR-944/TRIM37 axis in sepsis-induced ALI, implying that NEAT1 may provide a novel insight for the treatment of sepsis-induced ALI.

Inhibition of microRNA-15 protects H9c2 cells against CVB3-induced myocardial injury by targeting NLRX1 to regulate the NLRP3 inflammasome

Background

Viral myocarditis (VMC) is a type of cardiac inflammation that is generally caused by coxsackievirus B3 (CVB3) infection. Several MicroRNAs (miRNAs) are known to play crucial roles in VMC pathogenesis. MiR-15 is reportedly associated with myocardial injury, inflammatory responses and viral infection. Whether miR-15 affects the occurrence and development of VMC remains largely unknown. The roles of miR-15 and their underlying mechanisms in CVB3-stimulated H9c2 cells were assessed in this study.

Methods

We infected H9c2 cells with CVB3 to establish a VMC cellular model. We then determined the effects of miR-15 inhibition on three cardiomyocyte injury markers: lactate dehydrogenase (LDH), creatine kinase-MB (CK-MB) and cardiac troponin-I (cTn-I). The impact on CVB3-induced cell apoptosis and pro-inflammatory cytokines was also investigated. The effects of miR-15 inhibition on NLRP3 inflammasome activation were also assessed. The target relationship between miR-15 and NOD-like receptor X1 (NLRX1) was determined using a luciferase reporter assay.

Results

MiR-15 expression was significantly upregulated in H9c2 cells after CVB3 infection. Inhibition of miR-15 significantly decreased the CVB3-induced levels of LDH, CK-MB and cTn-I. It also elevated cell viability, reduced CVB3-induced cell apoptosis and decreased the generation of the interleukins IL-1β, IL-6 and IL-18. Furthermore, we determined that miR-15 inhibition suppressed NLRP3 inflammasome activation by downregulating NLRP3 and caspase-1 p20 expression. We found a direct target relationship between miR-15 and NLRX1. Additionally, inhibition of NLRX1 reversed the protective effects of miR-15 inhibition against CVB3-induced myocardial cell injury by regulating the NLRP3 inflammasome.

Conclusion

Our results indicate that miR-15 inhibition alleviates CVB3-induced myocardial inflammation and cell injury. This may be partially due to NLRX1-mediated NLRP3 inflammasome inactivation.