MicroRNAs as biomarkers of acute lung injury

The suppression of nuclear factor kappa B/microRNA 222 axis alleviates lipopolysaccharide-induced acute lung injury through increasing the alkylglyceronephosphate synthase expression

BACKGROUND

Acute lung injury (ALI) is a serious and rapidly progressing pulmonary disorder with a high mortality rate. In this study, we aimed to investigate the relationship between miR-222 and NF-κB (p65) activation in ALI.

METHODS

ALI was induced in mice using lipopolysaccharide (LPS). Lung tissues and bronchoalveolar lavage fluid were collected for analysis. MH-S cell lines were used as an ALI model. Various techniques including histopathology, molecular analysis, and cell culture assays were employed.

RESULTS

Increased miR-222 levels were observed in the LPS-induced ALI mouse model. ALI mice exhibited severe lung pathology, inflammatory cell infiltration, edema, elevated W/D ratio, MPO activity, and increased TNFα, IL1, and IL6 levels, which were reversed by miR-222 antagomir, confirming miR-222's exacerbation of LPS-induced ALI. miR-222 directly targeted the 3'-UTR of alkylglyceronephosphate synthase (AGPS) mRNA, reducing its expression. AGPS is crucial for plasmalogen synthesis, which protects against oxidative stress. NF-κB (p-p65) levels were increased in ALI models, and LPS promoted the enrichment of the miR-222 promoter region, suggesting NF-κB (p65) involvement in miR-222 transcriptional regulation. The NF-κB/miR-222/AGPS axis played a significant role in ALI progression.

CONCLUSIONS

The present study indicates that NF-κB (p65) activates miR-222 transcription by enriching its promoter region, leading to increased miR-222 expression. Elevated miR-222 levels downregulate AGPS, thereby accelerating the progression of ALI. Targeting the NF-κB/miR-222/AGPS axis may hold promise as a therapeutic approach for ALI, although further research is needed to fully understand its significance.

Budesonide and N-acetylcysteine inhibit activation of the NLRP3 inflammasome by regulating miR-381 to alleviate acute lung injury caused by the pyroptosis-mediated inflammatory response

Background

The anti-inflammatory effects of budesonide (BUN) and N-acetylcysteine (NAC) attenuate acute lung injury (ALI). The aim of this study was to investigate the effects of combination therapy consisting of BUN and NAC on ALI and the underlying mechanisms.

Methods

In vitro and in vivo models of ALI were generated by LPS induction. Western blotting was used to detect the expression levels of pyroptosis-related proteins and inflammation-related factors, and RT-qPCR was used to detect the expression of miR-381. Cell proliferation and apoptosis were detected by CCK-8 and flow cytometry, respectively. ELISA was used to detect the levels of inflammation-related factors. HE staining was used to detect lung injury.

Results

The results showed that LPS effectively induced pyroptosis in cells and promoted the expression of pyroptosis-related proteins (Caspase1, Gasdermin D and NLRP3) and inflammatory cytokines (TNF-α, IL-6 and IL-1β). The combination of BUN and NAC significantly alleviated LPS-induced pyroptosis and inflammation. In addition, the combination of BUN and NAC effectively promoted miR-381 expression. Transfection of miR-381 mimics effectively alleviated LPS-induced pyroptosis and inflammation, while transfection of miR-381 inhibitors had the opposite effect. miR-381 negatively regulates NLRP3 expression. Treatment with a miR-381 inhibitor or pc-NLRP3 reversed the effects of the combination of BUN and NAC. In a mouse model of ALI, the combination of BUN and NAC effectively improved lung injury, while treatment with a miR-381 inhibitor or pc-NLRP3 effectively reversed this effect.

Conclusion

Overall, this study revealed that BUN + NAC inhibits the activation of NLRP3 by regulating miR-381, thereby alleviating ALI caused by pyroptosis-mediated inflammation.

miR-126a-5p inhibits H1N1-induced inflammation and matrix protease secretion in lung fibroblasts by targeting ADAMTS-4

Upregulation of ADAMTS-4 has been reported to have an important role in lung injury, and ADAMTS-4 expression is regulated by miR-126a-5p in abdominal aortic aneurysms. The aim of this study was to investigate whether miR-126a-5p/ADAMTS-4 plays a role in influenza-virus-induced lung injury. Lung fibroblasts were infected with H1N1 influenza virus to detect changes in miR-126a-5p and ADAMTS-4 expression, and cell viability was measured by CCK-8 assay. Inflammatory factors and matrix protease levels were examined using ELISA kits, and cell apoptosis was assessed by measuring the levels of apoptosis-related proteins. A dual luciferase assay was used to verify the regulatory relationship between miR-126a-5p and ADAMTS-4. H1N1 influenza virus reduced fibroblast viability, inhibited miR-126a-5p expression, and promoted ADAMTS-4 expression. Overexpression of miR-126a-5p attenuated the cellular inflammatory response, apoptosis, matrix protease secretion, and virus replication. Luciferase reporter assays revealed that miR-126a-5p inhibited ADAMTS-4 expression by targeting ADAMTS-4 mRNA. Further experiments showed that overexpression of ADAMTS-4 significantly reversed the inhibitory effects of miR-126a-5p on fibroblast inflammation, apoptosis, matrix protease secretion, and virus replication. Upregulation of miR-126a-5p inhibits H1N1-induced apoptosis, inflammatory factors, and matrix protease secretion, as well as virus replication in lung fibroblasts.

CircAGFG1 absence decreases PKM2 expression to enhance oxaliplatin sensitivity in colorectal cancer in a miR-7-5p-dependent manner

Circular RNA (circRNA) ArfGAP with FG repeats 1 (circAGFG1) contributes to colorectal cancer (CRC) development. However, whether circAGFG1 regulates the resistance of CRC to oxaliplatin (L-OHP) remains unknown. CircAGFG1, microRNA-7-5p (miR-7-5p) and pyruvate kinase M2 (PKM2) RNA expression were quantified by quantitative real-time polymerase chain reaction. Protein expression was detected by western blot assay and immunohistochemistry assay. Glycolysis was analyzed through glucose uptake, lactate production and adenosine triphosphate (ATP) concentration assays. 50% inhibitory concentration of L-OHP was determined by cell counting kit-8 assay. Cell proliferation and apoptotic rate were analyzed by cell colony formation and flow cytometry analysis, respectively. Dual-luciferase reporter assay was used to identify the relationship among circAGFG1, miR-7- 5p and PKM2. The effect of circAGFG1 on L-OHP sensitivity in vivo was further evaluated by a xenograft model assay. CircAGFG1 and PKM2 expression were significantly increased, while miR-7-5p was decreased in L-OHP-resistant CRC tissues and cells. High circAGFG1 expression predicted a poor prognosis of CRC. CircAGFG1 knockdown or PKM2 depletion decreased glycolysis and cell proliferation and increased L-OHP sensitivity and cell apoptosis. PKM2 introduction rescued circAGFG1 silencing-induced effects in CRC cells. In terms of mechanism, circAGFG1 bound to miR-7-5p, which was identified to target PKM2. Also, circAGFG1 regulated PKM2 expression by interacting with miR-7-5p. Further, circAGFG1 knockdown improved the sensitivity of tumors to L-OHP in vivo. CircAGFG1 depletion inhibited L-OHP resistance by regulating the miR-7-5p/PKM2 pathway.

Depletion of circ_0006459 protects human brain microvascular endothelial cells from oxygen-glucose deprivation-induced damage through the miR-940/FOXJ2 pathway

BACKGROUND

Multiple circular RNAs (circRNAs) play important roles in ischemic stroke. The present study aims to reveal the role and the mechanism of circ_0006459 in ischemic stroke.

METHODS

Human brain microvascular endothelial cells (HBMECs) were treated with oxygen-glucose deprivation (OGD) to mimic an in vitro ischemic stroke model. RNA expression of circ_0006459, microRNA-940 (miR-940), and forkhead box J2 (FOXJ2) was detected by quantitative real-time polymerase chain reaction. Cell proliferation was analyzed by cell counting kit-8 (CCK-8) and 5-Ethynyl-29-deoxyuridine (EdU) assays. Cell apoptotic rate was quantified by flow cytometry analysis. The protein expression of proliferating cell nuclear antigen (PCNA), clusters of differentiation 6 (CDK6), BCL2-associated x protein (Bax), B-cell lymphoma 2 (Bcl2), interleukin-1β (IL-1β), IL-8, IL-18 and tumor necrosis factor-α (TNF-α) was analyzed by Western blotting. The regulatory relationships among circ_0006459, miR-940, and F 《》 OXJ2 were identified by dual-luciferase reporter assay, RNA immunoprecipitation assay, and RNA pull-down assay.

RESULTS

Circ_0006459 and FOXJ2 expression were significantly upregulated, whereas miR-940 expression was downregulated in HBMECs after OGD. Circ_0006459 depletion assuaged OGD-induced inhibition in cell proliferation and promotion in cell apoptosis and inflammation in HBMECs. Circ_0006459 acted as a sponge for miR-940, and miR-940 targeted FOXJ2 in HBMECs. Besides, miR-940 silencing or FOXJ2 overexpression relieved circ_0006459 knockdown-induced promotion in cell proliferation and inhibition in cell apoptosis and inflammation in OGD-induced HBMECs. Further, circ_0006459 depletion decreased FOXJ2 protein expression by interacting with miR-940.

CONCLUSION

Depletion of circ_0006459 protected human brain microvascular endothelial cells from oxygen-glucose deprivation-induced damage through miR-940/FOXJ2 pathway, providing a promising therapeutic target for ischemic stroke.

Investigating the link between miR-34a-5p and TLR6 signaling in sepsis-induced ARDS

Acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) are lung complications diagnosed by impaired gaseous exchanges leading to mortality. From the diverse etiologies, sepsis is a prominent contributor to ALI/ARDS. In the present study, we retrieved sepsis-induced ARDS mRNA expression profile and identified 883 differentially expressed genes (DEGs). Next, we established an ARDS-specific weighted gene co-expression network (WGCN) and picked the blue module as our hub module based on highly correlated network properties. Later we subjected all hub module DEGs to form an ARDS-specific 3-node feed-forward loop (FFL) whose highest-order subnetwork motif revealed one TF (STAT6), one miRNA (miR-34a-5p), and one mRNA (TLR6). Thereafter, we screened a natural product library and identified three lead molecules that showed promising binding affinity against TLR6. We then performed molecular dynamics simulations to evaluate the stability and binding free energy of the TLR6-lead molecule complexes. Our results suggest these lead molecules may be potential therapeutic candidates for treating sepsis-induced ALI/ARDS. In-silico studies on clinical datasets for sepsis-induced ARDS indicate a possible positive interaction between miR-34a and TLR6 and an antagonizing effect on STAT6 to promote inflammation. Also, the translational study on septic mice lungs by IHC staining reveals a hike in the expression of TLR6. We report here that miR-34a actively augments the effect of sepsis on lung epithelial cell apoptosis. This study suggests that miR-34a promotes TLR6 to heighten inflammation in sepsis-induced ALI/ARDS.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-023-03700-1.

Salivary miRNA Profiles in COVID-19 Patients with Different Disease Severities

The oral mucosa is the first site of SARS-CoV-2 entry and replication, and it plays a central role in the early defense against infection. Thus, the SARS-CoV-2 viral load, miRNAs, cytokines, and neutralizing activity (NA) were assessed in saliva and plasma from mild (MD) and severe (SD) COVID-19 patients. Here we showed that of the 84 miRNAs analyzed, 8 were differently expressed in the plasma and saliva of SD patients. In particular: (1) miRNAs let-7a-5p, let-7b-5p, and let-7c-5p were significantly downregulated; and (2) miR-23a and b and miR-29c, as well as three immunomodulatory miRNAs (miR-34a-5p, miR-181d-5p, and miR-146) were significantly upregulated. The production of pro-inflammatory cytokines (IL-1β, IL-2, IL-6, IL-8, IL-9, and TNFα) and chemokines (CCL2 and RANTES) increased in both the saliva and plasma of SD and MD patients. Notably, disease severity correlated with NA and immune activation. Monitoring these parameters could help predict disease outcomes and identify new markers of disease progression.

CircSLCO3A1 depletion ameliorates lipopolysaccharide-induced inflammation and apoptosis of human pulmonary alveolar epithelial cells through the miR-424-5p/HMGB3 pathway

Background

Recent studies have shown the pathogenesis of acute lung injury (ALI) involves circular RNA (circRNA). However, there are no data on the role of circSLCO3A1 in ALI and the underlying mechanism.

Objective

ALI-like cell injury was induced by stimulating human pulmonary alveolar epithelial cells (HPAEpiCs) using lipopolysaccharide (LPS). The expression of circSLCO3A1, miR-424-5p and high mobility group box 3 (HMGB3) was detected by quantitative real-time polymerase chain reaction. Cell viability and cell apoptosis were assessed by cell counting kit-8 (CCK-8) assay and flow cytometry analysis, respectively. Enzyme-linked immunosorbent assay was performed to determine the production of interleukin-1β (IL-1β), IL-6, tumor necrosis factor-α (TNF-α) and monocyte chemotactic protein 1 (MCP-1). Caspase-3 activity was detected by caspase-3 activity assay. Protein expression of inducible NOS (iNOS), cyclooxygenase-2 (COX2), p-p65 and p65 was analyzed by Western blot. The interactions among circSLCO3A1, miR-424-5p and HMGB3 were identified by dual-luciferase reporter assay, RNA immunoprecipitation assay and RNA pull-down assay.

Results

CircSLCO3A1 and HMGB3 expression were significantly increased, while miR-424-5p was decreased in LPS-treated HPAEpiCs and the serum of septic ALI patients in comparison with controls. CircSLCO3A1 knockdown assuaged LPS-induced HPAEpiC inflammation and apoptosis. Besides, circSLCO3A1 targeted miR-424-5p and regulated LPS-triggered HPAEpiC inflammation and apoptosis by binding to miR-424-5p. Under the treatment of LPS, miR-424-5p mediated HPAEpiC disorders by targeting HMGB3. Importantly, circSLCO3A1 modulated HMGB3 production by interacting with miR-424-5p.

Conclusion

CircSLCO3A1 absence assuaged LPS-induced HPAEpiC inflammation and apoptosis through the miR-424-5p/HMGB3 axis.

Highlights

CircSLCO3A1 expression was upregulated in LPS-induced HPAEpiCs and sepsis-induced ALI patients.CircSLCO3A1 depletion protected against LPS-induced HPAEpiC disorders.CircSLCO3A1 bound to miR-424-5p in HPAEpiCs.MiR-424-5p targeted HMGB3 in HPAEpiCs.CircSLCO3A1 regulated HMGB3 expression through miR-424-5p.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13273-023-00341-6.

Extracellular vesicle-transmitted miR-671-5p alleviates lung inflammation and injury by regulating the AAK1/NF-κB axis

Mesenchymal stem cells regulate remote intercellular signaling communication via their secreted extracellular vesicles. Here, we report that menstrual blood-derived stem cells alleviate acute lung inflammation and injury via their extracellular vesicle-transmitted miR-671-5p. Disruption of this abundantly expressed miR-671-5p dramatically reduced the ameliorative effect of extracellular vesicles released by menstrual blood-derived stem cells on lipopolysaccharide (LPS)-induced pulmonary inflammatory injury. Mechanistically, miR-671-5p directly targets the kinase AAK1 for post-transcriptional degradation. AAK1 is found to positively regulate the activation of nuclear factor κB (NF-κB) signaling by controlling the stability of the inhibitory protein IκBα. This study identifies a potential molecular basis of how extracellular vesicles derived from mesenchymal stem cells improve pulmonary inflammatory injury and highlights the functional importance of the miR-671-5p/AAK1 axis in the progression of pulmonary inflammatory diseases. More importantly, this study provides a promising cell-based approach for the treatment of pulmonary inflammatory disorders through an extracellular vesicle-dependent pathway.

MicroRNA-598 inhibition ameliorates LPS-induced acute lung injury in mice through upregulating Ebf1 expression

Acute lung injury is a critical acute respiratory distress syndrome (ARDS) with high morbidity and mortality. MicroRNAs (miRNAs) have been demonstrated to play important roles regulating acute lung injury development. In this study, we found that the expression of miR-598 was significantly upregulated in the lung tissues of mice with lipopolysaccharide (LPS)-induced acute lung injury. Both loss-of-function and gain-of-function studies were performed to evaluate the function of miR-598 in acute lung injury. The results showed that inhibition of miR-598 attenuated inflammatory response, oxidative stress, and lung injury in mice treated with LPS, while overexpression of miR-598 exacerbated the LPS-induced acute lung injury. Mechanistically, transcription factor Early B-cell Factor-1 (Ebf1) was predicted and validated as a downstream target of miR-598. Overexpression of Ebf1 attenuated LPS-induced production of inflammatory cytokine TNF-α and IL-6, ameliorated LPS-induced oxidative stress, promoted proliferation, and inhibited apoptosis in murine lung epithelial-15 (MLE-15) cells. Moreover, we demonstrated that Ebf1 knockdown abolished the protective effect of miR-598 inhibition in LPS-treated MLE-15 cells. In summary, miR-598 inhibition ameliorates LPS-induced acute lung injury in mice through upregulating Ebf1 expression, which might provide potential therapeutic treatment for acute lung injury.

Resveratrol attenuates staphylococcal enterotoxin B-activated immune cell metabolism via upregulation of miR-100 and suppression of mTOR signaling pathway

Acute Respiratory Distress Syndrome (ARDS) is triggered by a variety of insults, such as bacterial and viral infections, including SARS-CoV-2, leading to high mortality. In the murine model of ARDS induced by Staphylococcal enterotoxin-B (SEB), our previous studies showed that while SEB triggered 100% mortality, treatment with Resveratrol (RES) completely prevented such mortality by attenuating inflammation in the lungs. In the current study, we investigated the metabolic profile of SEB-activated immune cells in the lungs following treatment with RES. RES-treated mice had higher expression of miR-100 in the lung mononuclear cells (MNCs), which targeted mTOR, leading to its decreased expression. Also, Single-cell RNA-seq (scRNA seq) unveiled the decreased expression of mTOR in a variety of immune cells in the lungs. There was also an increase in glycolytic and mitochondrial respiration in the cells from SEB + VEH group in comparison with SEB + RES group. Together these data suggested that RES alters the metabolic reprogramming of SEB-activated immune cells, through suppression of mTOR activation and its down- and upstream effects on energy metabolism. Also, miR-100 could serve as novel potential therapeutic molecule in the amelioration of ARDS.

Pulmonary inflammatory response and immunomodulation to multiple trauma and hemorrhagic shock in pigs

BACKGROUND

Patients suffering from severe trauma experience substantial immunological stress. Lung injury is a known risk factor for the development of posttraumatic complications, but information on the long-term course of the pulmonary inflammatory response and treatment with mild hypothermia are scarce.

AIM

To investigate the pulmonary inflammatory response to multiple trauma and hemorrhagic shock in a porcine model of combined trauma and to assess the immunomodulatory properties of mild hypothermia.

METHODS

Following induction of trauma (blunt chest trauma, liver laceration, tibia fracture), two degrees of hemorrhagic shock (45 and 50%) over 90 (n = 30) and 120 min. (n = 20) were induced. Animals were randomized to hypothermia (33°C) or normothermia (38°C). We evaluated bronchoalveolar lavage (BAL) fluid and tissue levels of cytokines and investigated changes in microRNA- and gene-expression as well as tissue apoptosis.

RESULTS

We observed a significant induction of Interleukin (IL) 1β, IL-6, IL-8, and Cyclooxygenase-2 mRNA in lung tissue. Likewise, an increased IL-6 protein concentration could be detected in BAL-fluid, with a slight decrease of IL-6 protein in animals treated with hypothermia. Lower IL-10 protein levels in normothermia and higher IL-10 protein concentrations in hypothermia accompanied this trend. Tissue apoptosis increased after trauma. However, intervention with hypothermia did not result in a meaningful reduction of pro-inflammatory biomarkers or tissue apoptosis.

CONCLUSION

We observed signs of a time-dependent pulmonary inflammation and apoptosis at the site of severe trauma, and to a lower extent in the trauma-distant lung. Intervention with mild hypothermia had no considerable effect during 48 hours following trauma.

Regulating Function of miR-146a Derived from Bone Marrow Mesenchymal Stem Cell (BMSC) in Acute Lung Injury

This study assesses the mechanism of miR-146a derived from Bone marrow mesenchymal stem cell (BMSC) in acute lung injury. The model of ALI rats was established through endotracheal perfusion of LPS followed by analysis histological changes by HE staining. The source of BMSC was detected through flow cytometry and change of miRNA was detected through Array method. The miR-146a level in lung tissue was detected with RT-PCR and expression of Bcl-2, Bax and Capase-9 was detected with IF and Western Blot. A high expression of CD90 and CD105 was found in BMSC with negative CD11bc and CD34 level. 39 downregulated miRNAs and 20 upregulated miRNAs were found in ALI with miR-146a being the most significant. The apoptotic level induced with LPS could be restrained by miR-146a. In addition, miR-146a could upregulate Bcl-2 and downregulate Bax and Caspase-9. In conclusion, ALI could be restrained by the low expression of miR-146a.

Plasma microRNA and metabolic changes associated with pediatric acute respiratory distress syndrome: a prospective cohort study

Acute respiratory distress syndrome is a heterogeneous pathophysiological process responsible for significant morbidity and mortality in pediatric intensive care patients. Diagnosis is defined by clinical characteristics that identify the syndrome after development. Subphenotyping patients at risk of progression to ARDS could provide the opportunity for therapeutic intervention. microRNAs, non-coding RNAs stable in circulation, are a promising biomarker candidate. We conducted a single-center prospective cohort study to evaluate random forest classification of microarray-quantified circulating microRNAs in critically ill pediatric patients. We additionally selected a sub-cohort for parallel metabolomics profiling as a pilot study for concurrent use of miRNAs and metabolites as circulating biomarkers. In 35 patients (n = 21 acute respiratory distress, n = 14 control) 15 microRNAs were differentially expressed. Unsupervised random forest classification accurately grouped ARDS and control patients with an area under the curve of 0.762, which was improved to 0.839 when subset to only patients with bacterial infection. Nine metabolites were differentially abundant between acute respiratory distress and control patients (n = 4, both groups) and abundance was highly correlated with miRNA expression. Random forest classification of microRNAs differentiated critically ill pediatric patients who developed acute respiratory distress relative to those who do not. The differential expression of microRNAs and metabolites provides a strong foundation for further work to validate their use as a prognostic biomarker.

Targeting circNCLN/miR-291a-3p/TSLP signaling axis alleviates lipopolysaccharide-induced acute lung injury

Acute lung injury (ALI) is a life-threatening disease caused by the severe and acute response of the lungs to a variety of direct and indirect insults. Patients with ALI are currently treated mainly with respiratory support due to inadequate understanding of ALI progression. Alveolar epithelial cells produced thymic stromal lymphopoietin (TSLP) has been proved to worsen ALI by triggering airway inflammation. However, the regulation mechanism of TSLP expression remains unclear. In this study, we identified the crucial role played by circNCLN in lipopolysaccharide (LPS)-induced ALI. We demonstrated for the first time that miR-291a-3p could directly bind to the 3'UTR of TSLP and suppress TSLP expression in alveolar epithelial cells. Mechanistically, our data identified that circNCLN acts as a molecular sponge to antagonize miR-291a-3p and thereby maintaining the expression of TSLP in alveolar epithelial cells. Importantly, targeting circNCLN by its antisense oligonucleotide (ASO) markedly alleviated LPS-induced ALI. Therefore, our results suggested that circNCLN/miR-291a-3p/TSLP axis may be an important signaling in LPS-induced ALI and circNCLN inhibition may serve as a potential treatment of ALI.

Increased Serum Mir-150-3p Expression Is Associated with Radiological Lung Injury Improvement in Patients with COVID-19

Coronavirus disease 2019 (COVID-19) is caused by the SARS-CoV-2 virus, responsible for an atypical pneumonia that can progress to acute lung injury. MicroRNAs are small non-coding RNAs that control specific genes and pathways. This study evaluated the association between circulating miRNAs and lung injury associated with COVID-19. Methods: We evaluated lung injury by computed tomography at hospital admission and discharge and the serum expression of 754 miRNAs using the TaqMan OpenArray after hospital discharge in 27 patients with COVID-19. In addition, miR-150-3p was validated by qRT-PCR on serum samples collected at admission and after hospital discharge. Results: OpenArray analysis revealed that seven miRNAs were differentially expressed between groups of patients without radiological lung improvement compared to those with lung improvement at hospital discharge, with three miRNAs being upregulated (miR-548c-3p, miR-212-3p, and miR-548a-3p) and four downregulated (miR-191-5p, miR-151a-3p, miR-92a-3p, and miR-150-3p). Bioinformatics analysis revealed that five of these miRNAs had binding sites in the SARS-CoV-2 genome. Validation of miR-150-3p by qRT-PCR confirmed the OpenArray results. Conclusions: The present study shows the potential association between the serum expression of seven miRNAs and lung injury in patients with COVID-19. Furthermore, increased expression of miR-150 was associated with pulmonary improvement at hospital discharge.

MicroRNAs: Important Regulatory Molecules in Acute Lung Injury/Acute Respiratory Distress Syndrome

Acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) is an overactivated inflammatory response caused by direct or indirect injuries that destroy lung parenchymal cells and dramatically reduce lung function. Although some research progress has been made in recent years, the pathogenesis of ALI/ARDS remains unclear due to its heterogeneity and etiology. MicroRNAs (miRNAs), a type of small noncoding RNA, play a vital role in various diseases. In ALI/ARDS, miRNAs can regulate inflammatory and immune responses by targeting specific molecules. Regulation of miRNA expression can reduce damage and promote the recovery of ALI/ARDS. Consequently, miRNAs are considered as potential diagnostic indicators and therapeutic targets of ALI/ARDS. Given that inflammation plays an important role in the pathogenesis of ALI/ARDS, we review the miRNAs involved in the inflammatory process of ALI/ARDS to provide new ideas for the pathogenesis, clinical diagnosis, and treatment of ALI/ARDS.

MicroRNA-155-5p modulates the progression of acute respiratory distress syndrome by targeting interleukin receptors

Acute respiratory distress syndrome (ARDS) is a multifactorial inflammatory lung failure with a high incidence and a high cost burden. However, the underlying pathogenesis of ARDS is still unclear. Recently, microRNA has been shown to have critical function in regulating the pathogenesis of ARDS development and inflammation. To identify the important microRNA in the serum from patients with ARDS that may be potential biomarkers for the disease and explore the underlying disease mechanism. We found significant upregulation of miR-155-5p expression in serum samples from patients with ARDS compared with the control group (p < 0.01). The levels of interleukin receptors and inflammatory cytokines were significantly increased in blood samples from patients with ARDS (p < 0.05). In the cell model, miR-155-5p had a binding site in the 3’-UTR of the three interleukin receptors. In LPS-simulated BEAS-2B cells, transfection of miR-155-5p mimic inhibited the expression levels of these interleukin receptors, and was found to directly target the inflammatory response of leukocyte nodulin receptor through NF-kB signaling. In conclusion, miR-155-5p can alleviate LPS-simulated injury that induces the expression of IL17RB, IL18R1, and IL22RA2 by affecting the NF-kB pathway; however, it cannot change the occurrence of inflammatory storms. Collectively, this suggests that the progression of ARDS is the result of effects of the multiple regulatory pathways, providing novel evidence for the therapy of ARDS.

Knockdown of circRNA Paralemmin 2 Ameliorates Lipopolysaccharide-induced Murine Lung Epithelial Cell Injury by Sponging miR-330-5p to Reduce ROCK2 Expression

Previous data have reported the high expression of circRNA paralemmin 2 (circPALM2) in mice with acute lung injury (ALI). However, the role of circPALM2 in ALI pathogenesis remains unclear. The study aims to reveal the function of circPALM2 in ALI and the underlying mechanism. C57BL/6 J mice and murine lung epithelial-12 (MLE-12) cells were treated with lipopolysaccharide (LPS) to simulate ALI mouse and ALI cell models, respectively. Lung injury score and lung wet-to-dry ratio assays were used to evaluate the ALI mouse model. Quantitative real-time polymerase chain reaction and Western blot assays were implemented to analyze the expressions of circPALM2, microRNA-330-5p (miR-330-5p), rho-associated coiled-coil containing protein kinase 2 (ROCK2), and apoptosis-related markers. Cell viability, apoptosis, and the production of inflammatory cytokines were investigated by cell counting kit-8, flow cytometry, and enzyme-linked immunosorbent assays. The expressions of circPALM2 and ROCK2 were significantly increased, while miR-330-5p was decreased in ALI mice and LPS-induced MLE-12 cells compared with controls. LPS treatment inhibited cell viability but induced apoptosis, inflammatory cytokine production, and oxidative stress; however, these effects were attenuated after the combination of circPALM2 knockdown and LPS. CircPALM2 regulated LPS-caused MLE-12 cell damage by targeting miR-330-5p. Additionally, ROCK2, a target gene of miR-330-5p, participated in LPS-induced MLE-12 cell injury. Further, circPALM2 activated ROCK2 by associating with miR-330-5p. CircPALM2 modulated LPS-caused murine lung epithelial cell injury by the miR-330-5p/ROCK2 pathway, providing a therapeutic target for ALI.

Prognostic value of pulmonary ultrasound score combined with plasma miR-21-3p expression in patients with acute lung injury

Purpose

The aim of this study was to explore the value of the combination between lung ultrasound score (LUS) and the expression of plasma miR‐21‐3p in predicting the prognosis of patients with acute lung injury (ALI).

Patients and methods

A total of 136 ALI patients were divided into survival (n = 86) and death groups (n = 50), or into low/middle‐risk (n = 77) and high‐risk groups (n = 59) according to APACHE II scores. Bioinformatics was used to explore the mechanism of action of miR‐21‐3p in humans. Real‐time fluorescent quantitative PCR was used to detect the expression of miR‐21‐3p in plasma, and LUS was recorded. Receiver operator characteristic (ROC) curve and Pearson correlation were also used.

Results

The LUS and expression level of plasma miR‐21‐3p in the death and high‐risk groups were significantly higher than those in the survival and low/middle‐risk groups (p < 0.01 and p < 0.05). miR‐21‐3p expression leads to pulmonary fibrosis and promotes the deterioration of ALI patients by regulating fibroblast growth factor and other target genes. ROC curve analysis showed that the best cutoff values for LUS and plasma miR‐21‐3p expression were 18.60 points and 1.75, respectively. LUS score and miR‐21‐3p combined predicted the death of ALI patients with the largest area under the curve (0.907, 95% CI: 0.850–0.964), with sensitivity and specificity of 91.6% and 85.2%, respectively. The expression level of plasma miR‐21‐3p was positively correlated with LUS in the death group (r = 0.827, p < 0.01).

Conclusion

LUS and expression level of miR‐21‐3p in plasma are correlated with the severity and prognosis of ALI patients, and their combination has a high value for the prognostic assessment of ALI patients.

Association of cardiometabolic microRNAs with COVID-19 severity and mortality

AIMS

Coronavirus disease 2019 (COVID-19) can lead to multiorgan damage. MicroRNAs (miRNAs) in blood reflect cell activation and tissue injury. We aimed to determine the association of circulating miRNAs with COVID-19 severity and 28 day intensive care unit (ICU) mortality.

METHODS AND RESULTS

We performed RNA-Seq in plasma of healthy controls (n = 11), non-severe (n = 18), and severe (n = 18) COVID-19 patients and selected 14 miRNAs according to cell- and tissue origin for measurement by reverse transcription quantitative polymerase chain reaction (RT-qPCR) in a separate cohort of mild (n = 6), moderate (n = 39), and severe (n = 16) patients. Candidates were then measured by RT-qPCR in longitudinal samples of ICU COVID-19 patients (n = 240 samples from n = 65 patients). A total of 60 miRNAs, including platelet-, endothelial-, hepatocyte-, and cardiomyocyte-derived miRNAs, were differentially expressed depending on severity, with increased miR-133a and reduced miR-122 also being associated with 28 day mortality. We leveraged mass spectrometry-based proteomics data for corresponding protein trajectories. Myocyte-derived (myomiR) miR-133a was inversely associated with neutrophil counts and positively with proteins related to neutrophil degranulation, such as myeloperoxidase. In contrast, levels of hepatocyte-derived miR-122 correlated to liver parameters and to liver-derived positive (inverse association) and negative acute phase proteins (positive association). Finally, we compared miRNAs to established markers of COVID-19 severity and outcome, i.e. SARS-CoV-2 RNAemia, age, BMI, D-dimer, and troponin. Whilst RNAemia, age and troponin were better predictors of mortality, miR-133a and miR-122 showed superior classification performance for severity. In binary and triplet combinations, miRNAs improved classification performance of established markers for severity and mortality.

CONCLUSION

Circulating miRNAs of different tissue origin, including several known cardiometabolic biomarkers, rise with COVID-19 severity. MyomiR miR-133a and liver-derived miR-122 also relate to 28 day mortality. MiR-133a reflects inflammation-induced myocyte damage, whilst miR-122 reflects the hepatic acute phase response.

miRNAs, from Evolutionary Junk to Possible Prognostic Markers and Therapeutic Targets in COVID-19

The COVID-19 pandemic has been a public health issue around the world in the last few years. Currently, there is no specific antiviral treatment to fight the disease. Thus, it is essential to highlight possible prognostic predictors that could identify patients with a high risk of developing complications. Within this framework, miRNA biomolecules play a vital role in the genetic regulation of various genes, principally, those related to the pathophysiology of the disease. Here, we review the interaction of host and viral microRNAs with molecular and cellular elements that could potentiate the main pulmonary, cardiac, renal, circulatory, and neuronal complications in COVID-19 patients. miR-26a, miR-29b, miR-21, miR-372, and miR-2392, among others, have been associated with exacerbation of the inflammatory process, increasing the risk of a cytokine storm. In addition, increased expression of miR-15b, -199a, and -491 are related to the prognosis of the disease, and miR-192 and miR-323a were identified as clinical predictors of mortality in patients admitted to the intensive care unit. Finally, we address miR-29, miR-122, miR-155, and miR-200, among others, as possible therapeutic targets. However, more studies are required to confirm these findings.

Different microRNAs contribute to the protective effect of mesenchymal stem cell-derived microvesicles in LPS induced acute respiratory distress syndrome

OBJECTIVES

The present study aimed to determine whether bone marrow mesenchymal stem cell-derived microvesicles (MSC MVs) were effective in restoring lung tissue structure, and to assess the potential role of miRNAs in the pathogenesis and progression of acute respiratory distress syndrome (ARDS).

MATERIALS AND METHODS

ARDS was induced by lipopolysaccharide in male C57BL/6 mice. The degree of lung injury was assessed by histological analysis, lung's wet weight/body weight, and protein levels in the bronchoalveolar lavage fluid (BALF). Sequencing was performed on the BGISEQ-500 platform. Differentially expressed miRNAs (DEMs) were screened with the DEGseq software. The target genes of DEMs were predicted by iRNAhybrid, miRanda, and TargetScan.

RESULTS

Compared with LPS-injured mice, MSC MVs reduced lung water and total protein levels in the BALF, demonstrating a protective effect. 52 miRNAs were differentially expressed following treatment with MSC MVs in ARDS mice. Among them, miR-532-5p, miR-223-3p, and miR-744-5p were significantly regulated. Gene Ontology (GO) function and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses revealed the target genes were mainly located in the cell, organelle, and membrane. Furthermore, KEGG pathways such as ErbB, PI3K-Akt, Ras, MAPK, Toll, and Wnt signaling pathways were the most significant pathways enriched by the target genes.

CONCLUSION

MSC MVs treatment was involved in alleviating lung injury and promoting lung tissue repair by dysregulated miRNAs.

Acute respiratory distress syndrome: a life threatening associated complication of SARS-CoV-2 infection inducing COVID-19

Acute Respiratory Distress Syndrome (ARDS) is a form of respiratory failure in human. The number of deaths caused by SARS-CoV-2 infection inducing this severe pneumonia (ARDS) is relatively high. In fact, COVID-19 might get worsen in ARDS and provoke respiratory failure. A better understood of ARDS key features and the pathophysiological injuries of the pulmonary parenchyma are linked to lessons learned from previous severe diseases associated previous coronaviruses outbreaks (especially SARS-CoV and MERS-CoV) and more the ongoing SARS-CoV-2. The ARDS mechanism includes a diffuse alveolar damage associated disruption of alveolar capillary membrane, pulmonary edema, damaged endothelium and increased permeability. A diffuse inflammation, with acute onset, on the lung tissue accompanied by release of biochemical signal and inflammatory mediators (TNFα, IL-1 and IL-6) leading to hypoxemia, low PaO2/FiO2 ratio and the chest radiological expression of bilateral infiltrates in ARDS. The ongoing outbreak could lead to a better understood of ARDS pathophysiology and prognostic. An overview is also highlighted about the seven coronaviruses proved to infect human especially those having ability to cause severe disease SARS-CoV, MERS-CoV and SARS-CoV-2. In this review, we focused on the major pathological mechanisms leading to the ARDS development as a result of viral infection, severe COVID-19 worsening. Communicated by Ramaswamy H. Sarma.

A novel miRNA-762/NFIX pathway modulates LPS-induced acute lung injury

Severe acute lung injury (ALI) cause significant morbidity and mortality worldwide. MicroRNAs (miRNAs) are possible biomarkers and therapeutic targets for ALI. We aimed to explore the role of miR-762, a known oncogenic factor, in the pathogenesis of ALI. Levels of miR-762 in lung tissues of LPS-treated ALI mice and blood cells of patients with lung injury were measured. Injury of human lung epithelial cell line A549 was induced by LPS stimulation. A downstream target of miR-762, NFIX, was predicted using online tools. Their interactions were validated by luciferase reporter assay. Effects of targeted regulation of the miR-762/NFIX axis on cell proliferation, apoptosis, and inflammatory responses were tested in vitro in A549 cells in vivo with an ALI mouse model. We found that upregulation of miR-762 expression and downregulation of NFIX expression were associated with lung injury. Either miR-762 inhibition or NFIX overexpression in A549 lung cells significantly attenuated LPS-mediated impairment of cell proliferation and viability. Notably, increasing expressions of miR-762 inhibitor or NFIX in vivo via airway lentivirus infection alleviated the LPS-induced ALI in mice. Further, targeted downregulation of miR-762 expression or upregulation of NFIX expression in A549 cells markedly down-regulates NF-κB/IRF3 activation, and substantially reduces the production of inflammatory factors, including TNF-α, IL-6, and IL-8. This study reveals a novel role for the miR-762/NFIX pathway in ALI pathogenesis and sheds new light on targeting this pathway for diagnosis, prevention, and therapy.

Circulating miRNAs as Promising Biomarkers to Evaluate ECMO Treatment Responses in ARDS Patients

The use of extracorporeal membrane oxygenation (ECMO) for acute respiratory distress syndrome (ARDS) has increased in the last decade. However, mortality remains high, and the complexity of ECMO requires individualized treatment. There are some biomarkers to monitor progression and predict clinical outcomes of ARDS. This project aims to advance the management of ARDS patients treated with ECMO by exploring miRNA expression in whole blood. The analysis was conducted on two groups with different length of ECMO: Group A (longer runs) and group B (shorter runs). We analyzed miRNAs before ECMO cannulation, and at 7 and 14 days of ECMO support. Our results showed that in the group B patients, 11 deregulated miRNAs were identified, and showed an opposite trend of expression compared to the group A patients. In silico analysis revealed that these 11 miRNAs were related to processes involved in the pathogenesis and evolution of ARDS. This scenario could represent homeostatic mechanisms by which, in ECMO responsive patients, pathways activated during ARDS progression are switched-off. Circulating miRNAs could represent promising biomarkers to monitor the evolution of ARDS under ECMO support. Further studies may shed light on this topic to improve a personalized approach in such a complex setting of patients.

MicroRNA-16 regulates lipopolysaccharide-induced inflammatory factor expression by targeting TLR4 in normal human bronchial epithelial cells

Acute lung injury (ALI) is mainly caused by inflammation and is associated with high mortality rates. Emerging evidence has suggested that microRNAs (miRNAs or miRs) serve a significant function in ALI. However, the fundamental mechanism underlying ALI remain to be fully elucidated. Although miR-16 has been reported to be involved in the occurrence and development of a number of diseases its association with ALI has not been previously investigated. Therefore, the present study aimed to explore the role of miR-16 in the lipopolysaccharide (LPS)-induced ALI model. The expression levels of tumor necrosis factor α (TNF-α), interleukin (IL)-1β and IL-6 were measured by ELISA in the blood samples of rats with ALI and in the normal human bronchial epithelial (NHBE) cell line. The role of miR-16 in inflammation was evaluated using gene overexpression and silencing experiments in NHBE cells by reverse transcription-quantitative PCR. In addition, the expression levels of inflammatory factors TNF-α, IL-1β and IL-6 were also determined using ELISA. The potential interaction between miR-16 and TLR4 was assessed using bioinformatics analysis by the TargetScan database and then verified in 293T cells using luciferase reporter assay. The expression of miR-16 was notably decreased in the lung tissues of rats with LPS-induced ALI compared with the PBS treated-group. Additionally, the levels of the proinflammatory cytokines TNF-α, IL-1β and IL-6 were reduced following transfection of NHBE cells with miR-16 mimics compared with those in the miR-negative control group. Western blot analysis revealed that miR-16 overexpression could downregulate TLR4 expression in NHBE cells compared with that in the miR-NC group. Luciferase reporter assay confirmed that TLR4 may be directly targeted by miR-16. The effect of miR-16 on TLR4 was rescued in NHBE cells following treatment with LPS. Overall, these aforementioned findings suggest that miR-16 may serve a protective role against LPS-mediated inflammatory responses in NHBE cells by regulating TLR4, where this mechanism may be considered to be a novel approach for treating ALI in the future.

Expression of DUSP12 Reduces Lung Vascular Endothelial Cell Damage in a Murine Model of Lipopolysaccharide-Induced Acute Lung Injury via the Apoptosis Signal-Regulating Kinase 1 (ASK1)-Jun N-Terminal Kinase Activation (JNK) Pathway

BACKGROUND Acute lung injury (ALI) results from damage to the alveolar capillary endothelial cells and can result in acute respiratory distress syndrome (ARDS). This study aimed to investigate murine lung vascular endothelial cells (MLECs) damage in a murine model of lipopolysaccharide (LPS)-induced ALI. MATERIAL AND METHODS Mice were injected with LPS to induce an acute lung injury model. An adenovirus transfection system was used to overexpress or knockdown DUSP12 in mice. MLECs were isolated, cultured and transfected with DUSP12-overexpressing adenovirus or with DUSP12 siRNA to knockdown DUSP12. LPS was used to establish a cell injury model. ELISA and RT-PCR were used to examine cell inflammation. LPS-induced oxidative stress was also evaluated using commercial kits. RESULTS A decreased level of DUSP12 was observed in MLECs treated with LPS. DUSP12 overexpression in mice attenuated LPS-induced lung inflammation and lung injury, as reflected by reduced levels of proinflammatory cytokines. Mice with DUSP12 knockdown exhibited worsened lung inflammation and injury. In vitro, DUSP12 overexpression in endothelial cells ameliorated LPS-induced inflammation, apoptosis, and oxidative stress. DUSP12 silencing in endothelial cells aggravated LPS-induced inflammation, apoptosis, and oxidative stress. Furthermore, we found that DUSP12 directly bound to apoptosis signal-regulating kinase 1 (ASK1) to inhibit Jun N-terminal kinase activation (JNK). A JNK1/2 inhibitor and ASK1 siRNA ameliorated the exacerbating effects of DUSP12 knockdown in vitro. CONCLUSIONS Our data demonstrated that DUSP12 suppressed MLEC injury in response to LPS insult by regulating the ASK1/JNK pathway.

Forsythoside A protects against lipopolysaccharide-induced acute lung injury through up-regulating microRNA-124

Acute lung injury (ALI) is a life-threatening disease without effective pharmacotherapies, so far. Forsythia suspensa is frequently used in the treatment of lung infection in traditional Chinese medicine. In search for natural anti-inflammatory components, the activity and the underlying mechanism of Forsythoside A (FA) from Forsythia suspensa were explored. In the present paper, BALB/c mice and murine RAW 264.7 cells were stimulated by LPS to establish inflammation models. Data showed that FA inhibited the production of TNF-α and IL-6 and the activation of STAT3 in LPS-stimulated RAW 264.7 cells. Additionally, FA increased the expression level of microRNA-124 (miR-124). Furthermore, the inhibitory effect of FA on STAT3 was counteracted by the treatment of miR-124 inhibitor. Critically, FA ameliorated LPS-induced ALI pathological damage, the increase in lung water content and inflammatory cytokine, cells infiltration and activation of the STAT3 signaling pathway in BALB/c mice. Meanwhile, FA up-regulated the expression of miR-124 in lungs, while administration with miR-124 inhibitor attenuated the protective effects of FA. Our results indicated that FA alleviates LPS-induced inflammation through up-regulating miR-124 in vitro and in vivo. These findings indicate the potential of FA and miR-124 in the treatment of ALI.

Blocking SNHG14 Antagonizes Lipopolysaccharides-Induced Acute Lung Injury via SNHG14/miR-124-3p Axis

BACKGROUND

Emerging evidence show that long noncoding RNAs (lncRNAs) are crucial regulators in pathophysiology of acute lung injury (ALI). Small nucleolar RNA host gene 14 (SNHG14) is a novel oncogenic lncRNA, and has been associated with inflammation-related cell injuries. Thus, we wondered the role and mechanism of SNHG14 in lipopolysaccharides (LPS)-induced ALI cell model.

METHODS

Expression of SNHG14, miRNA (miR)-124-3p, and transforming growth factor β type 2 receptor (TGFBR2) was detected by RT-qPCR and western blotting. Cell apoptosis was determined by methyl thiazolyl tetrazolium assay, flow cytometry, western blotting, and lactate dehydrogenase activity kit. Inflammation was measured by enzyme-linked immunosorbent assay. The interaction among SNHG14, miR-124-3p, and TGFBR2 was validated by dual-luciferase reporter assay and RNA immunoprecipitation.

RESULTS

LPS administration attenuated human lung epithelial cell viability and B-cell lymphoma-2 expression, but augmented apoptosis rate, cleaved-caspase-3 expression, lactate dehydrogenase activity, and secretions of tumor necrosis factor-α, interleukin-1β, and IL-6 in A549 cells. Thus, LPS induced A549 cells apoptosis and inflammation, wherein SNHG14 was upregulated and miR-124-3p was downregulated. However, silencing SNHG14 could suppress LPS-induced apoptosis and inflammation depending on upregulating miR-124-3p via target binding. Similarly, overexpressing miR-124-3p attenuated LPS-induced A549 cells injury through inhibiting its downstream target TGFBR2. Furthermore, SNHG14 knockdown could also affect TGFBR2 expression via miR-124-3p.

CONCLUSIONS

SNHG14 knockdown prevents A549 cells from LPS-induced apoptosis and inflammation through regulating miR-124-3p and TGFBR2, suggesting a novel SNHG14/miR-124-3p/TGFBR2 circuit in alveolar epithelial cells on the set of ALI.

miR-584 and miR-146 are candidate biomarkers for acute respiratory distress syndrome

MicroRNAs (miRNAs/miRs) have important roles in inflammation and infections, which are common manifestations of acute respiratory distress syndrome (ARDS). The present study aimed to assess whether serum miRNAs are potential diagnostic biomarkers for human ARDS. For this, two sets of serum samples from healthy individuals and patients with ARDS were analysed by high-throughput sequencing to identify differentially expressed genes in ARDS. A total of 679 valid sequences were identified as differentially expressed (P<0.05). Of these, five differentially expressed miRNAs were subjected to reverse transcription-quantitative PCR validation. Finally, two miRNAs (miR-584 and miR-146a) were successfully verified. These two miRNAs were significantly downregulated in the serum of patients with ARDS. Gene Ontology annotations and Kyoto Encyclopedia of Genes and Genomes pathway analysis revealed that their target transcripts were implicated in a broad range of biological processes and various metabolic pathways, including involvement in the regulation of various inflammatory factors. The present study provided a framework for understanding the molecular mechanisms of ARDS and suggested that miR-584 and miR-146a are associated with ARDS and may be potential therapeutic targets.

Thal protects against paraquat-induced lung injury through a microRNA-141/HDAC6/IκBα-NF-κB axis in rat and cell models

The protective functions of thalidomide in paraquat (PQ)-induced injury have been reported. But the mechanisms remain largely unknown. In this research, a PQ-treated rat model was established and further treated with thalidomide. Oedema and pathological changes, oxidative stress, inflammation, fibrosis and cell apoptosis in rat lungs were detected. A PQ-treated RLE-6TN cell model was constructed, and the viability and apoptosis rate of cells were measured. Differentially expressed microRNAs (miRNAs) after thalidomide administration were screened out. Binding relationship between miR-141 and histone deacetylase 6 (HDAC6) was validated. Altered expression of miR-141 and HDAC6 was introduced to identify their involvements in thalidomide-mediated events. Consequently, thalidomide administration alone exerted no damage to rat lungs; in addition it reduced PQ-induced oedema. The oxidative stress, inflammation and cell apoptosis in rat lungs were reduced by thalidomide. In RLE-6TN cells, thalidomide increased cell viability and decreased apoptosis. miR-141 was responsible for thalidomide-mediated protective events by targeting HDAC6. Overexpression of HDAC6 blocked the protection of thalidomide against PQ-induced injury via activating the IkBα-NF-κB signalling pathway. Collectively, this study evidenced that thalidomide protects lung tissues from PQ-induced injury through a miR-141/HDAC6/IkBα-NF-κB axis.

Nanoparticle delivery of microRNA-146a regulates mechanotransduction in lung macrophages and mitigates injury during mechanical ventilation

Mechanical ventilation generates injurious forces that exacerbate lung injury. These forces disrupt lung barrier integrity, trigger proinflammatory mediator release, and differentially regulate genes and non-coding oligonucleotides including microRNAs. In this study, we identify miR-146a as a mechanosensitive microRNA in alveolar macrophages that has therapeutic potential to mitigate lung injury during mechanical ventilation. We use humanized in-vitro systems, mouse models, and biospecimens from patients to elucidate the expression dynamics of miR-146a needed to decrease lung injury during mechanical ventilation. We find that the endogenous increase in miR-146a following injurious ventilation is not sufficient to prevent lung injury. However, when miR-146a is highly overexpressed using a nanoparticle delivery platform it is sufficient to prevent injury. These data indicate that the endogenous increase in microRNA-146a during mechanical ventilation is a compensatory response that partially limits injury and that nanoparticle delivery of miR-146a is an effective strategy for mitigating lung injury during mechanical ventilation.

DRD1 downregulation contributes to mechanical stretch-induced lung endothelial barrier dysfunction

Rationale: The lung-protective effects of dopamine and its role in the pathology of ventilator-induced lung injury (VILI) are emerging. However, the underlying mechanisms are still largely unknown.

Objective: To investigate the contribution of dopamine receptor dysregulation in the pathogenesis of VILI and therapeutic potential of dopamine D1 receptor (DRD1) agonist in VILI.

Methods: The role of dopamine receptors in mechanical stretch-induced endothelial barrier dysfunction and lung injury was studied in DRD1 knockout mice, in isolated mouse lung vascular endothelial cells (MLVECs), and in lung samples from patients who underwent pulmonary lobectomy with mechanical ventilation for different time periods.

Measurements and Main Results: DRD1 was downregulated in both surgical patients and mice exposed to mechanical ventilation. Prophylactic administration of dopamine or DRD1 agonist attenuated mechanical stretch-induced lung endothelial barrier dysfunction and lung injury. By contrast, pulmonary knockdown or global knockout of DRD1 exacerbated these effects. Prophylactic administration of dopamine attenuated mechanical stretch-induced α-tubulin deacetylation and subsequent endothelial hyperpermeability through DRD1 signaling. We identified that cyclic stretch-induced glycogen-synthase-kinase-3β activation led to phosphorylation and activation of histone deacetylase 6 (HDAC6), which resulted in deacetylation of α-tubulin. Upon activation, DRD1 signaling attenuated mechanical stretch-induced α-tubulin deacetylation and subsequent lung endothelial barrier dysfunction through cAMP/exchange protein activated by cAMP (EPAC)-mediated inactivation of HDAC6.

Conclusions: This work identifies a novel protective role for DRD1 against mechanical stretch-induced lung endothelial barrier dysfunction and lung injury. Further study of the mechanisms involving DRD1 in the regulation of microtubule stability and interference with DRD1/cAMP/EPAC/HDAC6 signaling may provide insight into therapeutic approaches for VILI.

COVID-19 biobank: features of the cytokine profile

Aim. Using a collection of samples from the biobank ofCityHospital № 40 ofSt. Petersburg, to study the cytokine profile in patients with coronavirus disease 2019 (COVID-19) and sepsis, in comparison with patients with abdominal inflammation and septicemia.

Material and methods. The study included serum samples from 181 patients with sepsis and COVID-19 (127 patients with a diagnosis confirmed by polymerase chain reaction (PCR); 54 patients with a negative PCR test, but with a characteristic computed tomographic lung performance) and 47 patients with abdominal sepsis. The content of cytokines was determined using a multiplex immunofluorescence analysis based on the Luminex xMAP technology using the HCYTOMAG60K panel — a soluble CD40 ligand (sCD40L), interleukin-1α (IL-1α), interleukin-1β (IL-1β), interleukin 6 (IL-6), interleukin 8 (IL-8), monocyte chemoattractant protein 1 (MCP-1), tumor necrosis factor alpha (TNFα), vascular endothelial growth factor (VEGF). Other laboratory parameters (C-reactive protein (CRP), ferritin, procalcitonin) were taken from patient records. Normality of distribution was assessed by the Shapiro-Wilk test. To compare groups, the Mann-Whitney test for independent samples, Wilcoxon test for dependent samples, and the Kruskal-Wallis test with Bonferroni correction for multiple comparisons were used.

Results. In patients with sepsis and COVID-19 infection, no differences in the concentrations of cytokines, ferritin and CRP were found between the groups with detected and not detected virus by PCR test. Based on this, this group was considered homogeneous when studying the cytokine profile. It was shown that in patients with sepsis and COVID-19, significantly higher levels of sCD40L (p<0,0001) and VEGF (p=0,037) and relatively low levels of CRP (p<0,0001), IL-6 (p<0,0001), IL-8 (p<0,0001), TNFα (p<0,00058).

Conclusion. These results indicate that sepsis in patients with COVID-19 courses with less elevation in inflammatory cytokine than in abdominal sepsis. At the same time, a critically high level of sCD40L indicates the significant endothelial damage.

Acute lung injury - from pathophysiology to treatment

Acute lung injury is characterized by acute respiratory insufficiency with tachypnea, cyanosis refractory to oxygen, decreased lung compliance, and diffuse alveolar infiltrates on chest X-ray. The 1994 American-European Consensus Conference defined "acute respiratory distress syndrome, ARDS" by acute onset after a known trigger, severe hypoxemia defined by PaO2/FiO2</=200 mm Hg, bilateral infiltrates on chest X-ray, and absence of cardiogenic edema. Milder form of the syndrome with PaO2/FiO2 between 200-300 mm Hg was named "acute lung injury, ALI". Berlin Classification in 2012 defined three categories of ARDS according to hypoxemia (mild, moderate, and severe), and the term "acute lung injury" was assigned for general description or for animal models. ALI/ARDS can originate from direct lung triggers such as pneumonia or aspiration, or from extrapulmonary reasons such as sepsis or trauma. Despite growing understanding the ARDS pathophysiology, efficacy of standard treatments, such as lung protective ventilation, prone positioning, and neuromuscular blockers, is often limited. However, there is an increasing evidence that direct and indirect forms of ARDS may differ not only in the manifestations of alterations, but also in the response to treatment. Thus, individualized treatment according to ARDS subtypes may enhance the efficacy of given treatment and improve the survival of patients.

Identification of a Circulating miRNA Signature to Stratify Acute Respiratory Distress Syndrome Patients

There is a need to improve acute respiratory distress syndrome (ARDS) diagnosis and management, particularly with extracorporeal membrane oxygenation (ECMO), and different biomarkers have been tested to implement a precision-focused approach. We included ARDS patients on veno-venous (V-V) ECMO in a prospective observational pilot study. Blood samples were obtained before cannulation, and screened for the expression of 754 circulating microRNA (miRNAs) using high-throughput qPCR and hierarchical cluster analysis. The miRNet database was used to predict target genes of deregulated miRNAs, and the DIANA tool was used to identify significant enrichment pathways. A hierarchical cluster of 229 miRNAs (identified after quality control screening) produced a clear separation of 11 patients into two groups: considering the baseline SAPS II, SOFA, and RESP score cluster A (n = 6) showed higher severity compared to cluster B (n = 5); p values < 0.05. After analysis of differentially expressed miRNAs between the two clusters, 95 deregulated miRNAs were identified, and reduced to 13 by in silico analysis. These miRNAs target genes implicated in tissue remodeling, immune system, and blood coagulation pathways. The blood levels of 13 miRNAs are altered in severe ARDS. Further investigations will have to match miRNA results with inflammatory biomarkers and clinical data.

Correlation between alterations of gut microbiota and miR-122-5p expression in patients with type 2 diabetes mellitus

Background

To investigate the correlation between gut microbiota and circulating microRNAs (miRNAs) in patients with primary diagnosis of type 2 diabetes mellitus (T2DM) and to explore the possible mechanisms of miRNA-gut microbiota crosstalke network in the regulation of the insulin signaling pathway and glucose homeostasis in T2DM.

Methods

T2DM patients and normal controls were recruited. Fasting plasma and fecal samples were collected from the subjects, and their biochemical indexes including fasting blood glucose (FBG), glycated hemoglobin (HbAlc), cholesterol (TC), total triglycerides (TG), high-density lipoprotein (HDL), low-density lipoprotein (LDL), and insulin were recorded. The variations in intestinal microbiota in the two groups were analyzed using 16S rRNA third-generation sequencing technology, and the differential expression of miRNAs between the groups was screened using miRNA high-throughput sequencing. The correlation and association between specifically changed intestinal microbiota and miRNA expressions were analyzed using a combination of bioinformatics analysis and statistical methods. Finally, 16S functional gene prediction analysis and target gene enrichment pathway analysis were carried out to predict relevant gut microbiota and miRNAs.

Results

Compared with normal controls, the biochemical indexes of HAlbc, FBG, TG, TC, LDL, HDL, and insulin were significantly different in T2DM patients (P<0.001, P<0.001, P=0.0125, P=0.98, P<0.001 P=0.022, and P=0.0013, respectively). The two groups also showed significantly different intestinal microbiota distribution and miRNA expression characteristics, including in the counts of Bacteriodes. uniformis and Phascolarctobacterium. Faecium (P=0.023, 0.031), which were negatively correlated (P=0.014, FC = -2.36) with the expression levels of serum miR-122-5p (r=−0.68, −0.60, P=0.01, 0.01).

Conclusions

This study discovered specific gut microbiota and miRNA characteristics in patients with a primary diagnosis of T2DM. A negative correlation between miR-122-5p and the intestinal bacteria Bacteriodes. uniformis and Phascolarctobacterium. Faecium was also revealed, suggesting that the crosstalke between miRNA and gut microbiota may regulate the insulin secretion and signal transduction by controling key genes of glucose metabolism during the development of T2DM.

The expression profile and bioinformatics analysis of microRNAs in human bronchial epithelial cells treated by beryllium sulfate

Beryllium and its compounds are systemic toxicants that mainly accumulate in the lungs. As a regulator of gene expression, microRNAs (miRNAs) were involved in some lung diseases. This study aimed to analyze the levels of some inflammatory cytokine and the differential expressions of miRNAs in human bronchial epithelial cells (16HBE) induced by beryllium sulfate (BeSO₄ ) and to further explore the biological functions of differentially expressed miRNAs. The profile of miRNAs in 16HBE cells was detected using the high-throughput sequencing between the control groups (n = 3) and the 150 μmol/L of BeSO₄ -treated groups (n = 3). Bioinformatics analysis of differentially expressed miRNAs was performed, including the prediction of target genes, Gene Ontology (GO) analysis, and the Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis. Quantitative real-time polymerase chain reaction (qRT-PCR) was applied to verify some damage-related miRNAs. We found that BeSO₄ can increase the levels of some inflammatory cytokine such as interleukin-10 (IL-10), tumor necrosis factor-alpha (TNF-α), interferon-γ (IFN-γ), inducible nitric oxide synthase (iNOS), and cyclooxygenase-2 (COX-2). And BeSO₄ altered miRNAs expression of 16HBE cells and a total of 179 differentially expressed miRNAs were identified, including 88 upregulated miRNAs and 91 downregulated miRNAs. The target genes predicted by 28 dysregulated miRNAs were mainly involved in the transcription regulation, signal transduction, MAPK, and VEGF signaling pathway. The qRT-PCR verification results were consistent with the sequencing results. miRNA expression profiling in 16HBE cells exposed to BeSO₄ provides new insights into the toxicity mechanism of beryllium exposure.

Identification and Validation of Potential miRNAs, as Biomarkers for Sepsis and Associated Lung Injury: A Network-Based Approach

Sepsis is a dysregulated immune response disease affecting millions worldwide. Delayed diagnosis, poor prognosis, and disease heterogeneity make its treatment ineffective. miRNAs are imposingly involved in personalized medicine such as therapeutics, due to their high sensitivity and accuracy. Our study aimed to reveal the biomarkers that may be involved in the dysregulated immune response in sepsis and lung injury using a computational approach and in vivo validation studies. A sepsis miRNA Gene Expression Omnibus (GEO) dataset based on the former analysis of blood samples was used to identify differentially expressed miRNAs (DEMs) and associated hub genes. Sepsis-associated genes from the Comparative Toxicogenomics Database (CTD) that overlapped with identified DEM targets were utilized for network construction. In total, 317 genes were found to be regulated by 10 DEMs (three upregulated, namely miR-4634, miR-4638-5p, and miR-4769-5p, and seven downregulated, namely miR-4299, miR-451a, miR181a-2-3p, miR-16-5p, miR-5704, miR-144-3p, and miR-1290). Overall hub genes (HIP1, GJC1, MDM4, IL6R, and ERC1) and for miR-16-5p (SYNRG, TNRC6B, and LAMTOR3) were identified based on centrality measures (degree, betweenness, and closeness). In vivo validation of miRNAs in lung tissue showed significantly downregulated expression of miR-16-5p corroborating with our computational findings, whereas expression of miR-181a-2-3p and miR-451a were found to be upregulated in contrast to the computational approach. In conclusion, the differential expression pattern of miRNAs and hub genes reported in this study may help to unravel many unexplored regulatory pathways, leading to the identification of critical molecular targets for increased prognosis, diagnosis, and drug efficacy in sepsis and associated organ injuries.

Role of microRNA-15a-5p/TNFAIP3-interacting protein 2 axis in acute lung injury induced by traumatic hemorrhagic shock

The present study aimed to investigate the role of microRNA (miR)-15a-5p in the pathogenesis of acute lung injury induced by traumatic hemorrhagic shock (THS), and to explore the underlying molecular mechanism. The expression level of miR-15a-5p was detected using reverse transcription-quantitative (RT-qPCR) and the association between miR-15a-5p and TNFAIP3-interacting protein 2 (TNIP2) was revealed using TargetScan and dual luciferase reporter assays. To investigate the effect of miR-15a-5p on THS-induced acute lung injury, a THS rat model was established. Lung capillary permeability and lung edema were then determined. Moreover, proinflammatory factors in the bronchoalveolar lavage fluid (BALF) and serum of the THS rat model were detected using ELISA. In addition, protein levels in the current study were measured via western blotting. It was revealed that miR-15a-5p was significantly upregulated in both patients with THS and samples from the THS rat model. TNIP2 represents a direct target of miR-15a-5p, and it was downregulated in both patients with THS and the THS rat model. Further analyses indicated that downregulation of miR-15a-5p significantly relieved acute lung injury induced by THS, evidenced by a decreased ratio of Evan's blue dye (EBD) in the BALF to EBD in plasma of THS rats, decreased lung permeability index and reduced lung wet/dry ratio. Inhibition of miR-15a-5p also decreased THS-induced upregulation of pro-inflammatory factors. Furthermore, the data revealed that THS-induced NF-κB activation in the lung tissues of rats was inhibited by miR-15a-5p knockdown. Moreover, it was demonstrated that all the effects of miR-15a-5p on THS rats were ablated following TNIP2 silencing. Taken together, the data of the current study indicate that miR-15a-5p downregulation serves a protective role in THS-induced acute lung injury via directly targeting TNIP2.

The Neat Dance of COVID-19: NEAT1, DANCR, and Co-Modulated Cholinergic RNAs Link to Inflammation

The COVID-19 pandemic exerts inflammation-related parasympathetic complications and post-infection manifestations with major inter-individual variability. To seek the corresponding transcriptomic origins for the impact of COVID-19 infection and its aftermath consequences, we sought the relevance of long and short non-coding RNAs (ncRNAs) for susceptibility to COVID-19 infection. We selected inflammation-prone men and women of diverse ages among the cohort of Genome Tissue expression (GTEx) by mining RNA-seq datasets from their lung, and blood tissues, followed by quantitative qRT-PCR, bioinformatics-based network analyses and thorough statistics compared to brain cell culture and infection tests with COVID-19 and H1N1 viruses. In lung tissues from 57 inflammation-prone, but not other GTEx donors, we discovered sharp declines of the lung pathology-associated ncRNA DANCR and the nuclear paraspeckles forming neuroprotective ncRNA NEAT1. Accompanying increases in the acetylcholine-regulating transcripts capable of controlling inflammation co-appeared in SARS-CoV-2 infected but not H1N1 influenza infected lung cells. The lung cells-characteristic DANCR and NEAT1 association with inflammation-controlling transcripts could not be observed in blood cells, weakened with age and presented sex-dependent links in GTEx lung RNA-seq dataset. Supporting active involvement in the inflammatory risks accompanying COVID-19, DANCR's decline associated with decrease of the COVID-19-related cellular transcript ACE2 and with sex-related increases in coding transcripts potentiating acetylcholine signaling. Furthermore, transcription factors (TFs) in lung, brain and cultured infected cells created networks with the candidate transcripts, indicating tissue-specific expression patterns. Supporting links of post-infection inflammatory and cognitive damages with cholinergic mal-functioning, man and woman-originated cultured cholinergic neurons presented differentiation-related increases of DANCR and NEAT1 targeting microRNAs. Briefly, changes in ncRNAs and TFs from inflammation-prone human lung tissues, SARS-CoV-2-infected lung cells and man and woman-derived differentiated cholinergic neurons reflected the inflammatory pathobiology related to COVID-19. By shifting ncRNA differences into comparative diagnostic and therapeutic profiles, our RNA-sequencing based Resource can identify ncRNA regulating candidates for COVID-19 and its associated immediate and predicted long-term inflammation and neurological complications, and sex-related therapeutics thereof. Our findings encourage diagnostics of involved tissue, and further investigation of NEAT1-inducing statins and anti-cholinergic medications in the COVID-19 context.

Inhibition Mir-92a Alleviates Oxidative Stress and Apoptosis of Alveolar Epithelial Cells Induced by Lipopolysaccharide Exposure through TLR2/AP-1 Pathway

OBJECTIVE

To probe into the role of miR-92a in alleviating oxidative stress and apoptosis of alveolar epithelial cell (AEC) injury induced by lipopolysaccharide (LPS) exposure through the Toll-like receptor (TLR) 2/activator protein-1 (AP-1) pathway.

METHODS

Acute lung injury (ALI) rat model and ALI alveolar epithelial cell model were constructed to inhibit the expression of miR-92a/TLR2/AP-1 in rat and alveolar epithelial cells (AECs), to detect the changes of oxidative stress, inflammatory response, and cell apoptosis in rat lung tissues and AECs, and to measure the changes of wet-dry weight (W/D) ratio in rat lung tissues.

RESULTS

Both inhibition of miR-92a expression and knockout of TLR2 and AP-1 gene could reduce LPS-induced rat ALI, alleviate pulmonary edema, inhibit oxidative stress and inflammatory response, and reduce apoptosis of lung tissue cells. In addition, the TLR2 and AP-1 levels in the lung tissues of ALI rats were noticed to be suppressed when inhibiting the expression of miR-92a, and the AP-1 level was also decreased after the knockout of TLR2 gene. Further, we verified this relationship in AECs and found that inhibition of miR-92a/TLR2/AP-1 also alleviated LPS-induced AEC injury, reduced cell apoptosis, and inhibited oxidative stress and inflammatory response. What is more, like that in rat lung tissue, the phenomenon also existed in AECs, that is, when the expression of miR-92a was inhibited, the expression of TLR2 and AP-1 was inhibited, and silencing TLR2 can reduce the expression level of AP-1.

CONCLUSION

MiR-92a/TLR2/AP-1 is highly expressed in ALI, and its inhibition can improve oxidative stress and inflammatory response and reduce apoptosis of AECs.

Silencing of long non-coding RNA MEG3 alleviates lipopolysaccharide-induced acute lung injury by acting as a molecular sponge of microRNA-7b to modulate NLRP3

We aimed to elucidate the roles of the long non-coding RNA (lncRNA) maternally expressed gene 3 (MEG3)/microRNA-7b (miR-7b)/NLR pyrin domain containing 3 (NLRP3) axis in lipopolysaccharide (LPS)-induced acute lung injury (ALI). Mouse alveolar macrophage NR8383 and mice were administrated with LPS to establish ALI models in vitro and in vivo. NLRP3 was silenced while miR-7b was overexpressed in LPS-induced NR8383 cell model of ALI. The interleukin-18 (IL-18) and IL-1β, as well as caspase-1, tumor necrosis factor-α (TNF-α) and IL-6 protein levels were assayed. To further investigate the underlying mechanisms of NLRP3 in ALI, lncRNA MEG3 was silenced and miR-7b was overexpressed in LPS-induced NR8383 cell model of ALI, after which in vivo experiments were performed for further verification. NLRP3 was highly expressed in LPS-induced NR8383 cell model of ALI. Silencing NLRP3 or overexpressing miR-7b inhibited IL-18 and IL-1β, as well as caspase-1, TNF-α and IL-6. LncRNA MEG3 could sponge miR-7b, and lncRNA MEG3 silencing or miR-7b overexpression downregulates NLRP3 expression, thus reducing IL-18 and IL-1β, as well as caspase-1, TNF-α and IL-6 levels. The in vivo experiments further confirmed the aforementioned findings. Silencing lncRNA MEG3 augments miR-7b binding to NLRP3 and downregulates NLRP3 expression, which ultimately improves LPS-induced ALI.

HIV Impairs Alveolar Macrophage Function via MicroRNA-144-Induced Suppression of Nrf2

BACKGROUND

Despite anti-retroviral therapy, HIV-1 infection increases the risk of pneumonia and causes oxidative stress and defective alveolar macrophage (AM) immune function. We have previously determined that HIV-1 proteins inhibit antioxidant defenses and impair AM phagocytosis by suppressing nuclear factor (erythroid-derived 2)-like 2 (Nrf2). Given its known effects on Nrf2, we hypothesize miR-144 mediates the HIV-1 induced suppression of Nrf2.

METHODS

Primary AMs isolated from HIV-1 transgenic (HIV-1 Tg) rats and wild type littermates (WT) as well as human monocyte-derived macrophages (MDMs) infected ex vivo with HIV-1 were used. We modulated miR-144 expression using a miR-144 mimic or an inhibitor to assay its effects on Nrf2/ARE activity and AM functions in vitro and in vivo.

RESULTS

MiR-144 expression was increased in AMs from HIV-1 Tg rats and in HIV-1-infected human MDMs compared to cells from WT rats and non-infected human MDMs, respectively. Increasing miR-144 with a miR-144 mimic inhibited the expression of Nrf2 and its downstream effectors in WT rat macrophages and consequently impaired their bacterial phagocytic capacity and H₂O₂ scavenging ability. These effects on Nrf2 expression and AM function were reversed by antagonizing miR-144 ex vivo or in the airways of HIV-1 Tg rats in vivo, but this protection was abrogated by silencing Nrf2 expression.

CONCLUSIONS

Our results suggest that inhibiting miR-144 or interfering with its deleterious effects on Nrf2 attenuates HIV-1-mediated AM immune dysfunction and improves lung health in individuals with HIV.

MicroRNA: Potential biomarker and target of therapy in acute lung injury

MicroRNAs (miRNAs) are small noncoding RNAs stretching over 18-22 nucleotides and considered to be modifiers of many respiratory diseases. They are highly evolutionary conserved and have been implicated in several biological processes, including cell proliferation, apoptosis, differentiation, among others. Acute lung injury (ALI) is a fatal disease commonly caused by direct or indirect injury factors and has a high mortality rate in intensive care unit. Changes in expression of several types of miRNAs have been reported in patients with ALI. Some miRNAs suppress cellular injury and accelerate the recovery of ALI by targeting specific molecules and decreasing excessive immune response. For this reason, miRNAs are proposed as potential biomarkers for ALI and as therapeutic targets for this disease. This review summarizes current evidence supporting the role of miRNAs in ALI.

Microarray and bioinformatics analysis of circular RNAs expression profile in traumatic lung injury

Acute lung injury (ALI) and respiratory distress syndrome are common, potentially lethal injuries that predominantly occur following chest trauma. Circular RNAs (circRNAs) are stable conserved non-coding RNAs that are widely expressed in different organs. To the best of our knowledge, no previous studies have shown whether circRNAs are involved in traumatic lung injury (TLI). The aim of the present study was to identify highly expressed circRNAs in plasma samples from patients with TLI and explore their potential functions in the pathogenesis of TLI. A high-throughput circRNA microarray was used to investigate the expression profile of circRNAs in plasma samples from five patients with TLI and paired control samples. Subsequently, a total of five abnormally expressed circRNAs were investigated using reverse transcription-quantitative PCR (RT-qPCR). A bioinformatics analysis was performed to predict a competitive endogenous RNA (ceRNA) network. In addition, gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were used to identify the main biological processes and pathways. Finally, additional samples were tested to identify the expression profiles of the selected circRNAs. Among the 310 circRNAs that were highly expressed in the microarray analysis, 60 were upregulated and 250 were downregulated in patients with TLI. RT-qPCR results indicated that two downregulated circRNAs (circ_102927 and circ_100562) and one upregulated circRNA (circ_101523) matched the microarray results. The bioinformatics analysis constructed a targeting network based on the three validated circRNAs. GO and KEGG analyses identified the top ten enriched annotations. The expression of homo sapiens circular RNA 102927 (hsa_circRNA_102927) in the plasma of patients with TLI was 0.34-fold compared with the control group in expanded size validation. The results of the present study identified the differentially expressed circRNAs in the plasma of patients with TLI and provided evidence that highly expressed circRNAs involved in the ceRNA network may serve a role in the pathophysiology of TLI.

miR-144-mediated Inhibition of ROCK1 Protects against LPS-induced Lung Endothelial Hyperpermeability

Dysfunctional endothelial cell (EC) barrier and increased lung vascular permeability is a cardinal feature of acute lung injury and sepsis that may result in a pathophysiological condition characterized by alveolar flooding, pulmonary edema, and subsequent hypoxemia. In lung ECs, activation of Rho-associated kinase-1 (ROCK1) phosphorylates myosin light chain (MLC)-associated phosphatase at its inhibitory site, which favors phosphorylation of MLC, stress fiber formation, and hyperpermeability during acute lung injury. The role of microRNA-144 (miR-144) has been well investigated in many human diseases, including cardiac ischemia/reperfusion-induced injury, lung cancer, and lung viral infection; however, its role in pulmonary EC barrier regulation remains obscure. Here, we investigated the miR-144-mediated mechanism in the protection of endothelial barrier function in an LPS-induced lung injury model. By using transendothelial electrical resistance and transwell permeability assay to examine in vitro permeability and immunofluorescence microscopy to determine barrier integrity, we showed that ectopic expression of miR-144 effectively blocked lung EC barrier disruption and hyperpermeability in response to proinflammatory agents. Furthermore, using a gain-and-loss-of-function strategy, overexpression of miR-144 significantly decreased ROCK1 expression. Concomitantly, miR-144 inhibits ROCK1-mediated phosphorylation of MLC phosphatase^Thr853 and thus phosphorylation of MLC^Thr18/Ser19 to counteract stress fiber formation in LPS-activated EC. Finally, in LPS-challenged mice, intranasal delivery of miR-144 mimic via liposomes attenuated endotoxemia-induced increases in lung wet/dry ratio, vascular permeability, and inflammation. In conclusion, these data suggest that miR-144-attenuated activation of inflammatory ROCK1/MLC pathway in vascular ECs is a promising therapeutic strategy to counter inflammatory lung injury.

MicroRNA-34a Promotes Endothelial Dysfunction and Mitochondrial-mediated Apoptosis in Murine Models of Acute Lung Injury

Recent evidence has shown that microRNAs (miRs) are involved in endothelial dysfunction and vascular injury in lung-related diseases. However, the potential role of miR-34a in the regulation of pulmonary endothelial dysfunction, vascular injury, and endothelial cells (ECs) apoptosis in acute lung injury (ALI)/acute lung respiratory distress syndrome is largely unknown. Here, we show that miR-34a-5p was upregulated in whole lungs, isolated ECs from lungs, and ECs stimulated with various insults (LPS and hyperoxia). Overexpression of miR-34a-5p in ECs exacerbated endothelial dysfunction, inflammation, and vascular injury, whereas the suppression of miR-34a-5p expression in ECs and miR-34a-null mutant mice showed protection against LPS- and hyperoxia-induced ALI. Furthermore, we observed that miR-34a-mediated endothelial dysfunction is associated with decreased miR-34a direct-target protein, sirtuin-1, and increased p53 expression in whole lungs and ECs. Mechanistically, we show that miR-34a leads to translocation of p53 and Bax to the mitochondrial compartment with disruption of mitochondrial membrane potential to release cytochrome C into the cytosol, initiating a cascade of mitochondrial-mediated apoptosis in lungs. Collectively, these data show that downregulating miR-34a expression or modulating its target proteins may improve endothelial dysfunction and attenuate ALI.