MicroRNAs: Novel regulatory molecules in acute lung injury/acute respiratory distress syndrome

Manufacturing, quality control, and GLP-grade preclinical study of nebulized allogenic adipose mesenchymal stromal cells-derived extracellular vesicles

BACKGROUND

Human adipose stromal cells-derived extracellular vesicles (haMSC-EVs) have been shown to alleviate inflammation in acute lung injury (ALI) animal models. However, there are few systemic studies on clinical-grade haMSC-EVs. Our study aimed to investigate the manufacturing, quality control (QC) and preclinical safety of clinical-grade haMSC-EVs.

METHODS

haMSC-EVs were isolated from the conditioned medium of human adipose MSCs incubated in 2D containers. Purification was performed by PEG precipitation and differential centrifugation. Characterizations were conducted by nanoparticle tracking analysis, transmission electron microscopy (TEM), Western blotting, nanoflow cytometry analysis, and the TNF-α inhibition ratio of macrophage [after stimulated by lipopolysaccharide (LPS)]. RNA-seq and proteomic analysis with liquid chromatography tandem mass spectrometry (LC-MS/MS) were used to inspect the lot-to-lot consistency of the EV products. Repeated toxicity was evaluated in rats after administration using trace liquid endotracheal nebulizers for 28 days, and respiratory toxicity was evaluated 24 h after the first administration. In vivo therapeutic effects were assessed in an LPS-induced ALI/ acute respiratory distress syndrome (ARDS) rat model.

RESULTS

The quality criteria have been standardized. In a stability study, haMSC-EVs were found to remain stable after 6 months of storage at - 80°C, 3 months at - 20 °C, and 6 h at room temperature. The microRNA profile and proteome of haMSC-EVs demonstrated suitable lot-to-lot consistency, further suggesting the stability of the production processes. Intratracheally administered 1.5 × 108 particles/rat/day for four weeks elicited no significant toxicity in rats. In LPS-induced ALI/ARDS model rats, intratracheally administered haMSC-EVs alleviated lung injury, possibly by reducing the serum level of inflammatory factors.

CONCLUSION

haMSC-EVs, as an off-shelf drug, have suitable stability and lot-to-lot consistency. Intratracheally administered haMSC-EVs demonstrated excellent safety at the tested dosages in systematic preclinical toxicity studies. Intratracheally administered haMSC-EVs improved the lung function and exerted anti-inflammatory effects on LPS-induced ALI/ARDS model rats.

Dual Delivery of Tetramethylpyrazine and miR-194-5p Using Soft Mesoporous Organosilica Nanoparticles for Acute Lung Injury Therapy

Background

The respiratory system is intensely damaged by acute lung injury (ALI). The anti-inflammatory effects of tetramethylpyrazine (TMP) against ALI have been confirmed, but it exhibits a short half-life. miR-194-5p could directly target Rac1, but the internalization rate of miRNA cells was low.

Purpose

To explore the potential of the soft mesoporous organic silica nanoplatform (NPs) as carriers for delivery of TMP and miR-194-5p through the tail vein.

Methods

NPs@TMP and NPs@PEI@miR-194-5p were added to the HUVEC cell-lines, in vitro, to observe the cell uptake and cytotoxic effects. In vivo experiments were conducted by injecting fluorescently labeled NPs through the tail vein and tracking distribution. Therapeutic and toxic side-effects were analyzed systemically.

Results

In vitro study exhibited that NPs have no toxic effect on HUVECs within the experimental parameters and have excellent cellular uptake. The IVIS Spectrum Imaging System shows that NPs accumulate mainly in the lungs. NPs@TMP treatment can improved oxidative stress and inflammation levels in ALI mice and inhibited the TLR4/NLRP3/caspase 1 pathway. NPs@PEI@miR-194-5p can inhibit the Rac1/ZO-1/occludin pathway and improved endothelial cell permeability in ALI mice. The co-treatment of NPs@TMP and NPs@PEI@miR-194-5p can significantly improved the survival rates of the mice, reduced pulmonary capillary permeability and improved pathological injury in ALI mice.

Innovation

This study combined traditional Chinese medicine, bioinformatics, cellular molecular biology and nanobiomedicine to study the pathogenesis and treatment of ALI. The rate of cellular internalization was improved by changing the shape and hardness of nanoparticles. NPs@TMP and NPs@PEI@miR-194-5p combined application can significantly improve the survival condition and pathological injury of mice.

Conclusion

NPs loaded with TMP and miR-194-5p showed a greater therapeutic effect in ALI mice.

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.

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.

Mechanism of CAV and CAVIN Family Genes in Acute Lung Injury based on DeepGENE

BACKGROUND

The fatality rate of acute lung injury (ALI) is as high as 40% to 60%. Although various factors, such as sepsis, trauma, pneumonia, burns, blood transfusion, cardiopulmonary bypass, and pancreatitis, can induce ALI, patients with these risk factors will eventually develop ALI. The rate of developing ALI is not high, and the outcomes of ALI patients vary, indicating that it is related to genetic differences between individuals. In a previous study, we found multiple functions of cavin-2 in lung function. In addition, many other studies have revealed that CAV1 is a critical regulator of lung injury. Due to the strong relationship between cavin-2 and CAV1, we suspect that cavin-2 is also associated with ALI. Furthermore, we are curious about the role of the CAV family and cavin family genes in ALI.

METHODS

To reveal the mechanism of CAV and CAVIN family genes in ALI, we propose DeepGENE to predict whether CAV and CAVIN family genes are associated with ALI. This method constructs a gene interaction network and extracts gene expression in 84 tissues. We divided these features into two groups and used two network encoders to encode and learn the features.

RESULTS

Compared with DNN, GBDT, RF and KNN, the AUC of DeepGENE increased by 7.89%, 16.84%, 20.19% and 32.01%, respectively. The AUPR scores increased by 8.05%, 15.58%, 22.56% and 23.34%. DeepGENE shows that CAVIN-1, CAVIN-2, CAVIN-3 and CAV2 are related to ALI.

CONCLUSION

DeepGENE is a reliable method for identifying acute lung injury-related genes. Multiple CAV and CAVIN family genes are associated with acute lung injury-related genes through multiple pathways and gene functions.

Mechanistic Understanding of Lung Inflammation: Recent Advances and Emerging Techniques

Acute respiratory distress syndrome (ARDS) is a life-threatening lung injury characterized by an acute inflammatory response in the lung parenchyma. Hence, it is considered as the most appropriate clinical syndrome to study pathogenic mechanisms of lung inflammation. ARDS is associated with increased morbidity and mortality in the intensive care unit (ICU), while no effective pharmacological treatment exists. It is very important therefore to fully characterize the underlying pathobiology and the related mechanisms, in order to develop novel therapeutic approaches. In vivo and in vitro models are important pre-clinical tools in biological and medical research in the mechanistic and pathological understanding of the majority of diseases. In this review, we will present data from selected experimental models of lung injury/acute lung inflammation, which have been based on clinical disorders that can lead to the development of ARDS and related inflammatory lung processes in humans, including ventilation-induced lung injury (VILI), sepsis, ischemia/reperfusion, smoke, acid aspiration, radiation, transfusion-related acute lung injury (TRALI), influenza, Streptococcus (S.) pneumoniae and coronaviruses infection. Data from the corresponding clinical conditions will also be presented. The mechanisms related to lung inflammation that will be covered are oxidative stress, neutrophil extracellular traps, mitogen-activated protein kinase (MAPK) pathways, surfactant, and water and ion channels. Finally, we will present a brief overview of emerging techniques in the field of omics research that have been applied to ARDS research, encompassing genomics, transcriptomics, proteomics, and metabolomics, which may recognize factors to help stratify ICU patients at risk, predict their prognosis, and possibly, serve as more specific therapeutic targets.

Emodin Ameliorates Acute Pancreatitis-Associated Lung Injury Through Inhibiting the Alveolar Macrophages Pyroptosis

Objective: To investigate the protective effect of emodin in acute pancreatitis (AP)-associated lung injury and the underlying mechanisms. Methods: NaT-AP model in rats was constructed using 3.5% sodium taurocholate, and CER+LPS-AP model in mice was constructed using caerulein combined with Lipopolysaccharide. Animals were divided randomly into four groups: sham, AP, Ac-YVAD-CMK (caspase-1 specific inhibitor, AYC), and emodin groups. AP-associated lung injury was assessed with H&E staining, inflammatory cytokine levels, and myeloperoxidase activity. Alveolar macrophages (AMs) pyroptosis was evaluated by flow cytometry. In bronchoalveolar lavage fluid, the levels of lactate dehydrogenase and inflammatory cytokines were measured by enzyme-linked immunosorbent assay. Pyroptosis-related protein expressions were detected by Western Blot. Results: Emodin, similar to the positive control AYC, significantly alleviated pancreas and lung damage in rats and mice. Additionally, emodin mitigated the pyroptotic process of AMs by decreasing the level of inflammatory cytokines and lactate dehydrogenase. More importantly, the protein expressions of NLRP3, ASC, Caspase1 p10, GSDMD, and GSDMD-NT in AMs were significantly downregulated after emodin intervention. Conclusion: Emodin has a therapeutic effect on AP-associated lung injury, which may result from the inhibition of NLRP3/Caspase1/GSDMD-mediated AMs pyroptosis signaling pathways.

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.

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.

Expression Level, Correlation, and Diagnostic Value of Serum miR-127 in Patients with Acute Respiratory Distress Syndrome

Objective

To analyze the expression of miR-127 in the serum of patients with acute respiratory distress syndrome (ARDS) and to explore its correlation with the severity of ARDS patients and its value as a molecular marker for diagnosis of ARDS.

Methods

70 patients with ARDS admitted to our hospital from September 2017 to September 2019 were selected as the observation group, and 60 healthy persons with physical examination were collected as the control group. RT-PCR was used to detect the serum miR-127 levels of all subjects, and the serum miR-127 levels of the observation group and control group were compared. The oxygenation index (PaO₂/FiO₂) of ARDS patients was recorded and divided into three subgroups: mild group, moderate group, and severe group. Serum miR-127 levels of patients in the mild group, moderate group, and severe group were compared. Pearson correlation was used to analyze the relationship between serum miR-127 levels and the severity of ARDS patients. The receiver operating characteristic curve (ROC) was drawn, and the area under the ROC curve (AUC) was used to evaluate the diagnostic value of miR-127 in patients with ARDS.

Results

The serum level of miR-127 (10.15 ± 1.03) in the observation group was significantly higher than that in the control group (3.09 ± 0.62). And in the three subgroups of mild, moderate, and severe, the serum miR-127 level in the moderate group (10.43 ± 0.71) and the severe group miR-127 level (11.05 ± 1.26) were significantly higher than those in the mild group level (9.38 ± 1.24). Pearson correlation analysis showed that the serum miR-127 level was negatively correlated with PaO₂/FiO₂ (r = −0.715, P < 0.05), that is, the serum miR-127 level was positively correlated with the severity of ARDS patients. The area under the curve (AUC) of the diagnostic value of serum miR-127 for ARDS was 0.732 (95% CI 0.607–0.858). When the optimal cutoff value was 0.380, the sensitivity was 59.1% and the specificity was 78.6%, which suggested that miR-127 can be used as a marker for ARDS diagnosis.

Conclusion

There is an increase in miR-127 levels in the serum of ARDS patients. The serum miR-127 level is positively correlated with the severity of ARDS. The higher the level of miR-127, the worse the condition of ARDS, which is positively correlated with the severity of the condition. It suggests that the serum miR-127 level is an important indicator for evaluating the severity of ARDS patients. It can be used as a molecular marker for clinical diagnosis of ARDS.

MiR-181b serves as diagnosis and prognosis biomarker in severe community-acquired pneumonia

Severe community-acquired pneumonia (SCAP) is a common critical disease in the intensive care unit (ICU). This study aims to evaluate the clinical significance of miR-181b in SCAP, which has been revealed to be dysregulated in acute respiratory distress syndrome events due to SCAP. There were 50 SCAP patients and 26 healthy volunteers were recruited in this study. The expression of miR-181b was detected by RT-qPCR and the difference between SCAP and healthy controls was evaluated. The diagnosis and prognosis value of miR-181b was assessed by the receiver operating characteristics (ROC), Kaplan-Meier, and Cox regression analysis. miR-181b was significantly downregulated in SCAP compared with healthy controls. The downregulation of miR-181b showed a significant association with the white blood cell count, absolute neutrophils, and the C-reactive protein of patients. The downregulation of miR-181b could distinguish SCAP patients from healthy controls and predicate the poor prognosis of SCAP patients. Downregulated miR-181b serves as a diagnosis and prognosis biomarker for SCAP, which may be useful biological information for the early detection and risk estimation of SCAP.

miR-128-3p reduced acute lung injury induced by sepsis via targeting PEL12

Objective

Acute lung injury (ALI) caused by sepsis is clinically a syndrome, which is featured by damage to the alveolar epithelium and endothelium. In this study, we employed mice models of cecal ligation and puncture (CLP) and primary mice pulmonary microvascular endothelial cells (MPVECs) in vitro to investigate the effect of miR-128-3p in ALI caused by sepsis.

Methods

miR-128-3p agomir or randomized control were injected into adult male C57BL/6 mice 1 week before the CLP surgery. We used miR-128-3p agomir or scrambled control to transfect MPVECs and then employed lipopolysaccharide (LPS) stimulation on the cells. Pellino homolog 2 (PELI2) was predicted to be a direct target of miR-128-3p via luciferase reporter assay. MPVECs were cotransfected with lentiviral vector that expressed PELI2 (or empty vector) as well as miR-128-3p-mimics 1 day before LPS stimulation in rescue experiment. Transcriptional activity of caspase-3, cell apoptosis rate, and the expression levels of miR-128-3p, interleukin-1β (IL-1β), interleukin-6 (IL-6), and PELI2 were analyzed.

Results

Compared with the sham group, the lung of mice in the CLP group showed pulmonary morphological abnormalities, and the expression of IL-6 and IL-1β, caspase-3 activity, and apoptosis rate were significantly upregulated in the CLP group. Inflammatory factor levels and apoptosis rate were also significantly induced by LPS stimulation on MPVECs. Upregulation of miR-128-3p effectively inhibited sepsis-induced ALI, apoptosis as well as inflammation. miR-128-3p also played a role in antiapoptosis and anti-inflammation in MPVECs with LPS treatment. PEL12 upregulation in MPVECs alleviated miR-128-3p-induced caspase-3 activity inhibition and pro-inflammatory factor production.

Conclusions

miR-128-3p enabled to alleviate sepsis-induced ALI by inhibiting PEL12 expression, indicating a novel treatment strategy of miR-128-3p for sepsis-induced ALI.

LncRNA OIP5-AS1 knockdown or miR-223 overexpression can alleviate LPS-induced ALI/ARDS by interfering with miR-223/NLRP3-mediated pyroptosis

BACKGROUND

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are life-threatening diseases and endothelial barrier injury is an important contributor to the pathogenesis of ALI/ARDS. LncRNA has been proved to participate in the progression of ALI/ARDS. Our study aimed to investigate the function of lncRNA OIP5-AS1 in LPS-induced ALI/ARDS.

METHODS

OIP5-AS1 and miR-223 levels were detected by PCR in the serum of ALI/ARDS patients or healthy donors. MTT assay were performed to detect the proliferation of HPMECs. Flow cytometry were performed to detect the apoptosis of HPMECs. The protein levels of NLRP3, ASC, GSDMD-N, caspase-1 were measured by western blot to detect the pyroptosis of HPMECs. IL-1β, IL-6, IL-18 and IL-10 was detected by ELISA to measure the inflammatory response of HPMECs. And production of ROS, SOD and MDA was measured to determine the oxidative stress of HPMECs. Targets of OIP5-AS1 and miR-223 were predicted by StarBase and confirmed by dual-luciferase reporter assay.

RESULTS

We found that OIP5-AS1 was upregulated, while miR-223 was downregulated in the serum of ALI/ARDS patients and LPS-treated HPMECs. Functionally, knockdown of OIP5-AS1 induced proliferation and inhibited apoptosis, pyroptosis, inflammatory response and oxidative stress of LPS-treated HPMECs. Interestingly, miR-223 was a target of OIP5-AS1 and miR-223 inhibition abolished the effects of si-OIP5-AS1 on LPS-induced HPMECs. More importantly, miR-223 directly targeted NLRP3, miR-223 overexpression also promoted proliferation and inhibited apoptosis, pyroptosis, inflammatory response and oxidative stress of LPS-treated HPMECs and which was abolished by NLRP3 overexpression. Finally, we found that OIP5-AS1 knockdown and miR-223 overexpression could both alleviate LPS-induced ALI/ARDS in vivo.

CONCLUSION

Together, we find that LncRNA OIP5-AS1 aggravates LPS-induced ALI/ARDS via miR-223/NLRP3 axis and provides new targets for ALI/ARDS therapy.

LncRNA XIST knockdown alleviates LPS-induced acute lung injury by inactivation of XIST/miR-132-3p/MAPK14 pathway : XIST promotes ALI via miR-132-3p/MAPK14 axis

Acute lung injury (ALI) is a fatal inflammatory response syndrome. LncRNA XIST (XIST) is a lung cancer-related gene and participates in pneumonia. However, whether XIST participates in lipopolysaccharides (LPS)-induced ALI remains unclear. LPS-induced inflammation model was constructed in vitro, then cell viability, cytokines, cell apoptosis, protein, and mRNA expressions were individually detected by cell counting kit-8, enzyme-linked immunosorbent assay and flow cytometry, Western blot, and qRT-PCR. A dual-luciferase reporter assay confirmed the relationships among XIST, miR-132-3p, and MAPK14. Furthermore, inflammation and conditions after knockdown of XIST were assessed by hematoxylin and eosin staining, lung wet-to-dry weight ratio, PaO₂/FiO₂ ratio, and malondialdehyde (MDA) contents using LPS-induced in vivo model. Our findings indicated that the LPS challenge decreased cell viability, increased cell apoptosis, and caused secretions of pro-inflammatory cytokines. Noticeably, LPS significantly upregulated XIST, MAPK14, and downregulated miR-132-3p. Mechanistically, XIST acted as a molecular sponge to suppress miR-132-3p, and MAPK14 was identified as a target of miR-132-3p. Functional analyses demonstrated that XIST silencing remarkably increased cell survival and alleviated cell death and lung injury through decreasing TNF-α, IL-1β, IL-6, accumulation of inflammatory cells, alveolar hemorrhage, MDA release, and increased PaO₂/FiO₂ ratio, as well as upregulating Bcl-2, and downregulating Bax, MAPK14, and p-extracellular signal-regulated kinases ½. In contrast, inhibition of the miR-132-3p antagonized the effects of XIST silencing. In conclusion, inhibition of XIST exhibited a protective role in LPS-induced ALI through modulating the miR-132-3p/MAPK14 axis.

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.

Macrophage activation in the lung during the progression of nitrogen mustard induced injury is associated with histone modifications and altered miRNA expression

Activated macrophages have been implicated in lung injury and fibrosis induced by the cytotoxic alkylating agent, nitrogen mustard (NM). Herein, we determined if macrophage activation is associated with histone modifications and altered miRNA expression. Treatment of rats with NM (0.125 mg/kg, i.t.) resulted in increases in phosphorylation of H2A.X in lung macrophages at 1 d and 3 d post-exposure. This DNA damage response was accompanied by methylation of histone (H) 3 lysine (K) 4 and acetylation of H3K9, marks of transcriptional activation, and methylation of H3K36 and H3K9, marks associated with transcriptional repression. Increases in histone acetyl transferase and histone deacetylase were also observed in macrophages 1 d and 28 d post-NM exposure. PCR array analysis of miRNAs (miR)s involved in inflammation and fibrosis revealed unique and overlapping expression profiles in macrophages isolated 1, 3, 7, and 28 d post-NM. An IPA Core Analysis of predicted mRNA targets of differentially expressed miRNAs identified significant enrichment of Diseases and Functions related to cell cycle arrest, apoptosis, cell movement, cell adhesion, lipid metabolism, and inflammation 1 d and 28 d post NM. miRNA-mRNA interaction network analysis revealed highly connected miRNAs representing key upstream regulators of mRNAs involved in significantly enriched pathways including miR-34c-5p and miR-27a-3p at 1 d post NM and miR-125b-5p, miR-16-5p, miR-30c-5p, miR-19b-3p and miR-148b-3p at 28 d post NM. Collectively, these data show that NM promotes histone remodeling and alterations in miRNA expression linked to lung macrophage responses during inflammatory injury and fibrosis.

Downregulation of miR-497-5p Improves Sepsis-Induced Acute Lung Injury by Targeting IL2RB

Introduction

Acute lung injury (ALI) induced by sepsis is a process related to inflammatory reactions, which involves lung cell apoptosis and production of inflammatory cytokine. Here, lipopolysaccharide (LPS) was applied to stimulate the mouse or human normal lung epithelial cell line (BEAS-2B) to construct a sepsis model in vivo and in vitro, and we also investigated the effect of miR-497-5p on sepsis-induced ALI. Material and Methods. Before LPS treatment, miR-497-5p antagomir was injected intravenously into mice to inhibit miR-497-5p expression in vivo. Similarly, miR-497-5p was knocked down in BEAS-2B cells. Luciferase reporter assay was applied to predict and confirm the miR-497-5p target gene. Cell viability, apoptosis, the levels of miR-497-5p, IL2RB, SP1, inflammatory cytokine, and lung injury were assessed.

Results

In BEAS-2B cells, a significant increase of apoptosis and inflammatory cytokine was shown after LPS stimulation. In septic mice, increased inflammatory cytokine production and apoptosis in lung cells and pulmonary morphological abnormalities were shown. The miR-497-5p inhibitor transfection showed antiapoptotic and anti-inflammatory effects on BEAS-2B cells upon LPS stimulation. In septic mice, the miR-497-5p antagomir injection also alleviated ALI, apoptosis, and inflammation caused by sepsis. The downregulation of IL2RB in BEAS-2B cells reversed the protective effects of the miR-497-5p inhibitor against ALI.

Conclusion

In conclusion, downregulation of miR-497-5p reduced ALI caused by sepsis through targeting IL2RB, indicating the potential effect of miR-497-5p for improving ALI caused by sepsis.

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.

Evaluation of miRNAs Related with Nuclear Factor Kappa B Pathway in Lipopolysaccharide Induced Acute Respiratory Distress Syndrome

This study aimed to determine the expression of nuclear factor kappa B (NF-κB) pathway related miRNAs in experimental acute respiratory distress syndrome (ARDS) induced by lipopolysaccharide (LPS) in rats, and to elucidate the underlying molecular mechanism. Twenty four sprague dawley rats were randomly divided into two groups; LPS (n = 12) and control (n = 12). Experimental ARDS was induced by intraperitoneal injection of E. coli LPS in LPS group. Intraperitoneal saline was administered in control group. Serum and lung samples were collected from both groups. Immunohistochemistry staining was performed for interleukin 1β (IL-1β), tumor necrosis factor α (TNF-α), CD 68, and caspase-3 in lung samples. Intensity of staining was scored as strong, moderate, weak, and no for evaluation of IL-1β and TNF-α. In addition, caspase-3 and CD68-positive stained cells were counted in sections. Expressions of 9 miRNAs were determined by quantitative real-time PCR in serum samples. IL-1β and TNF-α staining scores were significantly higher in the LPS group in comparison with the control group (P = 0.04 and P = 0.02, respectively). In addition, caspase-3 and CD68-positive stained cells were significantly higher in the LPS group (P = 0.02). Expressions of seven miRNAs were significantly changed in the LPS group in comparison with the control group. While six miRNAs (miR-7a-5p, miR-7b, miR-9a-5p, miR-21-5p, miR-29a-3p, and miR-138-5p) were up regulated, only miR-124-3p was down regulated. This study suggests that these miRNAs may have a role in the pathogenesis of ARDS related to NF-κB. However, this relationship needs to be examined in new studies by evaluation of pathways and target genes.

miR-138-5p targets sirtuin1 to regulate acute lung injury by regulation of the NF-κB signaling pathway

Acute lung injury (ALI), a disease with a high mortality rate, is a noncardiogenic pulmonary inflammatory response and characterized by damage to the pulmonary system. In this study, we explored the mechanism of the occurrence and development of ALI. It was firstly found that miR-138-5p could inhibit the expression of sirtuin1 (SIRT1), and we further demonstrated that miR-138-5p targets directly SIRT1 through the luciferase assay, while the latter negatively regulated the expression of NF-κB. A549 cells were treated with lipopolysaccharide in vitro to simulate ALI cells and induce ALI in the model mice. The results showed that inhibiting the expression of miR-138-5p could effectively increase the viability of damaged cells, promote cell proliferation, reduce apoptosis, inhibit the inflammatory response, reduce oxidative stress, and then relieve ALI symptoms. Collectively, our results suggested that miR-138-5p can inhibit SIRT1 expression and indirectly activate the NF-κB signaling pathway, thus regulating the development of ALI.

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.

miR-21-KO Alleviates Alveolar Structural Remodeling and Inflammatory Signaling in Acute Lung Injury

Acute lung injury (ALI) is characterized by enhanced permeability of the air–blood barrier, pulmonary edema, and hypoxemia. MicroRNA-21 (miR-21) was shown to be involved in pulmonary remodeling and the pathology of ALI, and we hypothesized that miR-21 knock-out (KO) reduces injury and remodeling in ALI. ALI was induced in miR-21 KO and C57BL/6N (wildtype, WT) mice by an intranasal administration of 75 µg lipopolysaccharide (LPS) in saline (n = 10 per group). The control mice received saline alone (n = 7 per group). After 24 h, lung function was measured. The lungs were then excised for proteomics, cytokine, and stereological analysis to address inflammatory signaling and structural damage. LPS exposure induced ALI in both strains, however, only WT mice showed increased tissue resistance and septal thickening upon LPS treatment. Septal alterations due to LPS exposure in WT mice consisted of an increase in extracellular matrix (ECM), including collagen fibrils, elastic fibers, and amorphous ECM. Proteomics analysis revealed that the inflammatory response was dampened in miR-21 KO mice with reduced platelet and neutrophil activation compared with WT mice. The WT mice showed more functional and structural changes and inflammatory signaling in ALI than miR-21 KO mice, confirming the hypothesis that miR-21 KO reduces the development of pathological changes in ALI.

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

Background

Acute respiratory distress syndrome (ARDS) is a severe form of acute lung injury during which severe inflammatory responses induce cell apoptosis, necrosis, and fibrosis. Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) is a multiple function long noncoding RNA that was found overexpressed during acute lung injury. However, the roles of MALAT1 in ARDS patients are still unknown.

Methods

Total RNA was extracted from the plasma, plasma exosome, and peripheral blood mononuclear cells (PBMCs) from 65 ARDS patients and 36 healthy controls. The MALAT1 and six candidate miRNAs levels were detected by qRT-PCR. The interaction between MALAT1 and miR-425 was predicted using a bioinformatics tool and verified by dual luciferase assay. Exosomes from ARDS patients were cultured with A549 and HFL-1 cells to confirm the delivery of miR-425 by exosomes. Cell apoptosis and viability were determined by flow cytometry and MTT assay.

Results

We found MALAT1 was significantly increased in the ARDS patients' plasma and PBMCs. The MALAT1 level in PBMCs was negatively correlated with exosomal miR-425 level. MALAT1 interacted with miR-425 and protected phosphatase and tensin homolog (PTEN) expression in A549 and HFL-1 cells. Exosomes from ARDS patients delivered less miR-425 into A549 and HFL-1 cells and induced cell apoptosis via upregulating PTEN.

Conclusion

This study identified increased MALAT1 and decreased miR-425 in ARDS patients and unveiled their roles during the pathogenesis of ARDS.

Mesenchymal stem cell-derived extracellular vesicles for the treatment of acute respiratory distress syndrome

Acute respiratory distress syndrome (ARDS) is a serious and potentially fatal acute inflammatory lung condition which currently has no specific treatments targeting its pathophysiology. However, mesenchymal stem cells have been shown to have very promising therapeutic potential, and recently, it has been established that their effect is largely due to the transfer of extracellular vesicles (EVs). EVs have been shown to transfer a variety of substances such as mRNA, miRNA, and even organelles such as mitochondria in order to ameliorate ARDS in preclinical models. In addition, the fact that they have been proven to have the same effect as their parent cells combined with their numerous advantages over whole cell administration means that they are a promising candidate for clinical application that merits further research.

Serum Exosomal MicroRNAs Predict Acute Respiratory Distress Syndrome Events in Patients with Severe Community-Acquired Pneumonia

BACKGROUND

Severe community-acquired pneumonia (SCAP) requiring intensive care unit (ICU) treatment commonly causes acute respiratory distress syndrome (ARDS) with high mortality. This study was aimed at evaluating whether microRNAs (miRNAs) in circulating exosomes have the predictive values for patients at risk of developing ARDS due to SCAP.

METHODS

ARDS/ALI-relevant miRNAs were obtained by literature search. Exosomes in serum were isolated by ultracentrifugation method and identified by Transmission Electron Microscopy. Then the miR profiling in the exosomes using real-time PCR was analyzed in SCAP patients with or without ARDS. Moreover, multivariate Cox proportional regression analysis was performed to estimate the odds ratio of miRNA for the occurrence of ARDS and prognosis. The receiver operating characteristics (ROC) curves were calculated to discriminate ARDS cases. Finally, the Kaplan-Meier curve using log-rank method was performed to test the equality for survival distributions with different miRNA classifiers.

RESULTS

A total of 53 SCAP patients were finally recruited. Ten miRNAs were picked out. Further, a subset of exosomal miRNAs, including the miR-146a, miR-27a, miR-126, and miR-155 in ARDS group exhibited significantly elevated levels than those in non-ARDS group. The combined expression of miR-126, miR-27a, miR-146a, and miR-155 predicted ARDS with an area under the curve of 0.909 (95 % CI 0.815 -1). Only miR-126 was selected to have potential to predict the 28-day mortality (OR=1.002, P=0.024) with its median value classifier.

CONCLUSIONS

The altered levels of circulating exosomal microRNAs may be useful biologic confirmation of ARDS in patients with SCAP.

miR-425 reduction causes aberrant proliferation and collagen synthesis through modulating TGF-β/Smad signaling in acute respiratory distress syndrome

Background: Acute respiratory distress syndrome (ARDS) is a severe form of acute lung injury which may trigger persistent fibrosis. Exosomes are small extracellular vesicles that reflecthost cell conditions and contain functional molecules including miRNAs. Methods: In this study, we isolated plasma exosomes from 53 ARDS patients and 53 controls. Six candidate miRNAs levels were determined by qRT-PCR. The H3K27me3 level on the promoter region of Smad2 was detected by ChIP assay followed by qPCR. Dual luciferase assay and immunoblotting were employed to verify the interaction between miRNA and target genes. The cells proliferation was determined by MTT dependent cell viability assay. Results: miR-425 was reduced in the ARDS patient exosomes. Cytokine treatment also reduced the miR-425 level in A549 and HFL-1 cells. miR-425 inhibition induced Smad2 overexpression by increasing KDM6A level and demethylated H3K27me3 in the Smad2 promoter region. miR-425 reduction induced collagen expression after TGF-β1 treatment and promoted fibroblast proliferation. Conclusion: We identified miR-425 reduction in the exosomes from ARDS patients' peripheral blood, which has the potential to be used as a biomarker for ARDS diagnosis. We demonstrated that miR-425 reduction in lung fibroblasts contributes to the fibrosis through upregulating KDM6A and then activates the TGF-β signaling pathway. This sheds light on the mechanism of lung fibrosis during ARDS.

MicroRNA‑223 attenuates LPS‑induced inflammation in an acute lung injury model via the NLRP3 inflammasome and TLR4/NF‑κB signaling pathway via RHOB

Acute lung injury (ALI) and the more severe acute respiratory distress syndrome are common and complex inflammatory lung diseases. MicroRNAs (miRs) have emerged as novel gene regulatory molecules, serving a crucial role in a variety of complex diseases, including ALI. In the present study, the anti‑inflammatory action of miR‑223 on inflammation in ALI was demonstrated and the possible mechanism was further examined. In lipopolysaccharide‑induced ALI, the expression of miR‑223 was reduced compared with that in the control normal group. An in vitro model was used to analyze the effect of miR‑223 downregulation on an ALI model, which increased inflammation, and induced the activation of the NACHT, LRR and PYD domains‑containing protein 3 (NLRP3) inflammasome and Toll‑like receptor 4 (TLR4)/nuclear factor (NF)‑κB signaling pathway via rho‑related GTP‑binding protein RhoB (RHOB). In addition, the overexpression of miR‑223 reduced inflammation and suppressed the NLRP3 inflammasome and TLR4/NF‑κB signaling pathway via RHOB in the in vitro model. Furthermore, TLR4 inhibitor or NLRP3 inhibitor reduced the pro‑inflammatory effect of miR‑223 downregulation in ALI. In conclusion, the results of the present study indicated that miR‑223 functioned as a biological indicator by regulating inflammation in ALI, and may represent a novel potential therapeutic target and prognostic marker of ALI.

Downregulated microRNA-27b attenuates lipopolysaccharide-induced acute lung injury via activation of NF-E2-related factor 2 and inhibition of nuclear factor κB signaling pathway

Acute lung injury (ALI) is a life-threatening, diffuse heterogeneous lung injury characterized by acute onset, pulmonary edema, and respiratory failure. Lipopolysaccharide (LPS) is a leading cause for ALI and when administered to a mouse it induces a lung phenotype exhibiting some of the clinical characteristics of human ALI. This study focused on investigating whether microRNA-27b (miR-27b) affects ALI in a mouse model established by LPS-induction and to further explore the underlying mechanism. After model establishment, the mice were treated with miR-27b agomir, miR-27b antagomir, or D-ribofuranosylbenzimidazole (an inhibitor of nuclear factor-E2-related factor 2 [Nrf2]) to determine levels of miR-27b, Nrf2, nuclear factor kappa-light-chain-enhancer of activated B cells nuclear factor κB (NF-κB), p-NF-κB, and heme oxygenase-1 (HO-1). The levels of interleukin (IL)-1β, IL-6, and tumor necrosis factor-α (TNF-α) in bronchoalveolar lavage fluid (BALF) were determined. The results of luciferase activity suggested that Nrf2 was a target gene of miR-27b. It was indicated that the Nrf2 level decreased in lung tissues from ALI mice. The downregulation of miR-27b decreased the levels of IL-1β, IL-6, and TNF-α in BALF of ALI mice. Downregulated miR-27b increased Nrf2 level, thus enhancing HO-1 level along with reduction of NF-κB level as well as the extent of NF-κB phosphorylation in the lung tissues of the transfected mice. Pathological changes were ameliorated in LPS-reduced mice elicited by miR-27b inhibition. The results of this study demonstrate that downregulated miR-27b couldenhance Nrf2 and HO-1 expressions, inhibit NF-κB signaling pathway, which exerts a protective effect on LPS-induced ALI in mice.

MicroRNA dysregulation in lung injury: the role of the miR-26a/EphA2 axis in regulation of endothelial permeability

MicroRNAs (miRNAs) are noncoding RNAs that regulate gene expression in many diseases, although the contribution of miRNAs to the pathophysiology of lung injury remains obscure. We hypothesized that dysregulation of miRNA expression drives the changes in key genes implicated in the development of lung injury. To test our hypothesis, we utilized a model of lung injury induced early after administration of intratracheal bleomycin (0.1 U). Wild-type mice were treated with bleomycin or PBS, and lungs were collected at 4 or 7 days. A profile of lung miRNA was determined by miRNA array and confirmed by quantitative PCR and flow cytometry. Lung miR-26a was significantly decreased 7 days after bleomycin injury, and, on the basis of enrichment of predicted gene targets, it was identified as a putative regulator of cell adhesion, including the gene targets EphA2, KDR, and ROCK1, important in altered barrier function. Lung EphA2 mRNA, and protein increased in the bleomycin-injured lung. We further explored the miR-26a/EphA2 axis in vitro using human lung microvascular endothelial cells (HMVEC-L). Cells were transfected with miR-26a mimic and inhibitor, and expression of gene targets and permeability was measured. miR-26a regulated expression of EphA2 but not KDR or ROCK1. Additionally, miR-26a inhibition increased HMVEC-L permeability, and the disrupted barrier integrity due to miR-26a was blocked by EphA2 knockdown, shown by VE-cadherin staining. Our data suggest that miR-26a is an important epigenetic regulator of EphA2 expression in the pulmonary endothelium. As such, miR-26a may represent a novel therapeutic target in lung injury by mitigating EphA2-mediated changes in permeability.

Mechanism of MCP-1 in Acute Lung Injury and Advanced Therapy by Drug-Loaded Dextrin Nanoparticle

Objective. To observe the expression of monocyte chemotactic protein 1 (MCP-1) in acute lung injury (ALI) rat model, to characterize its effect on the development and progression of ALI, and to identify the potential new drug delivery approach during in vivo experiment. Method. The effects of different doses of lipopolysaccharide (LPS) on human pulmonary artery endothelial cells (HPAEC) were tested. For the animal experiments, thirty Sprague-Dawley (SD) rats were divided into physiological saline control group (NC group), the LPS model group (L group), the antagonist RS102895 combined with LPS group (R + L group), and the antagonist RS102895-loaded polyaldehyde dextran nanoparticles combined with LPS group (DNPR + L group). The blood gas analysis and dry/wet weight ratio were detected 24 hours after interventions. The levels of inflammatory factors, tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β), were tested by ELISA. The expression of monocyte chemoattractant protein-1 (MCP-1) in lung tissues was examined through Western blot, and the change of MCP-1 mRNA expression level was detected by performing RT-PCR. Result. LPS was responsible for inducing ALI in rats, and the degree of cell damage was dose-dependent. Blood gas analysis of L group showed that PaO2 and PaO2/FiO2 levels were significantly lower than those of the NC group (P<0.05), while the dry/wet weight ratio of lung tissues in L group increased (P<0.05). Inflammatory factors including TNF-α and IL-1β and the expression of MCP-1 in both protein and mRNA levels were higher in L group than in the NC group (P<0.05). The inhibition of the interaction between MCP-1 and chemokines receptor 2 (CCR2) by antagonist RS102895 can significantly alleviate the ALI in rats, which is accompanied by a significant decrease of inflammatory factors and MCP-1 expression (P<0.05). Compared with R + L group, treatment with DNPR and LPS combination significantly improved the condition of rats and decreased the level of TNF-α, IL-1β, and MCP-1 expression (P<0.05). Conclusion. In ALI, RS102895 can inhibit the MCP-1/CCR2 interaction, therefore, retarding the progress of ALI. Because of the high transfection efficiency of inhibitor RS102895packgaed by polyaldehyde dextran nanoparticles, this phenomenon particularly reached a significant level. The results imply new insights for the treatment of ALI.

Upregulation of miRNA-140-5p inhibits inflammatory cytokines in acute lung injury through the MyD88/NF-κB signaling pathway by targeting TLR4

The present study was designed to determine the effect of miR-140-5p on acute lung injury (ALI) and the associated inflammation induced. As a result, miR-140-5p expression in mice with ALI was suppressed when compared with the normal group. Downregulation of miR-140-5p increased the levels of inflammatory factors induced by ALI [including tumor necrosis factor-α, interleukin (IL)-1β, IL-6 and myeloperoxidase] in an in vitro model of human lung A549 cells. Downregulation of miR-140-5p also induced the protein expression of Toll-like receptor 4 (TLR4), myeloid differentiation primary response 88 (MyD88) and nuclear factor (NF)-κB in an in vitro model. Overexpression of miR-140-5p reduced the levels of inflammation in the in vitro model of ALI via the suppression of the TLR4/MyD88/NF-κB signaling pathway. The inhibition of TLR4 using a TLR4 inhibitor reduced the proinflammation effects of anti-miR-140-5p in the in vitro model of ALI. The NF-κB inhibitor also inhibited the proinflammation effects of anti-miR-140-5p in the in vitro model of ALI. Overall, the results of the present study indicated that miR-140-5p inhibited ALI-induced inflammation via the TLR4/MyD88/NF-κB signaling pathway.

Expression profile of microRNAs following bone marrow-derived mesenchymal stem cell treatment in lipopolysaccharide-induced acute lung injury

Immunomodulatory or immunosuppressive properties of bone marrow-derived mesenchymal stem cells (BM-MSCs) facilitate the treatment of acute respiratory distress syndrome and acute lung injury (ALI). Dysregulated miRNA (miRNA or miR) expression associated with the effects of BM-MSCs was assessed in a rat model of lipopolysaccharide (LPS)-induced ALI. The present study performed biochemical tests to assess five analytes, including alanine aminotransferase (ALT), aspartate aminotransferase (AST), lactate, blood urea nitrogen (BUN), and creatinine (CREA). Total cell count was assessed and the percentage of bronchoalveolar lavage neutrophil content was also examined. The results Histopathological examination of rat upper lobe lung tissue was then used to estimate lung injury score (LIS). The levels of AST, lactate, BUN and creatinine (excluding ALT), released into the circulation upon injury, were significantly lower in ALI rats treated with BM-MSCs than in ALI rats alone (P<0.05). BM-MSC rats exhibited a significantly decreased bronchoalveolar lavage neutrophil percentage and LIS compared with that of LPS treated rats alone (P<0.05). In addition, the miRNA expression profile was determined following treatment with BM-MSCs via microarray analysis. A total of 95/690 miRNAs were differentially expressed following the treatment of BM-MSCs in rats with ALI. Among the 95 miRNAs, 66 were upregulated and 29 were downregulated; 9 miRNAs were significantly upregulated (miR-1843-3p, miR-323-3p, miR-183-5p, miR-182 and miR-196b-3p) or downregulated (miR-547-3p, miR-301b-5p, miR-503-3p and miR-142-3p). A total of 3 miRNAs were inversely expressed in ALI treated with BM-MSCs compared with untreated ALI. Of these 3 miRNAs, the expression of miR-142-3p and miR-503-3p was upregulated in the LPS groups and downregulated in the BM-MSC groups. miR-196b-3p was downregulated in the LPS group and upregulated in the BM-MSC groups. miRNAs have a role in cell proliferation, immune response, inflammation and apoptosis, which may be associated with the therapeutic effects of BM-MSCs in ALI. In summary, BM-MSCs improved multi-organ damage and attenuated lung injury. Different miRNA profiles were expressed following BM-MSC treatment of ALI. These dysregulated miRNAs participated in BM-MSC-mediated immunomodulation of ALI.

MicroRNA‑146a/Toll‑like receptor 4 signaling protects against severe burn‑induced remote acute lung injury in rats via anti‑inflammation

The present study investigated the preventive effects of microRNA (miR)‑146a against severe burn‑induced remote acute lung injury (ALI) in rats and the underlying mechanism. The surface area of the skin was immersed in 100˚C water for 5‑10 sec on the dorsal surface. The expression level of miR‑146a was significantly downregulated in rats with burn‑induced ALI. Downregulation of miR‑146a increased inflammation, and inducible nitric oxide synthase (iNOS) and cyclooxygenase‑2 (COX‑2) expression in a model of ALI in vitro via the promotion of the Toll‑like receptor (TLR)4/nuclear factor (NF)‑κB signaling pathway. In addition, the overexpression of miR‑146a reduced inflammation, and iNOS and COX‑2 protein expression in the model of ALI in vitro via the suppression of the TLR4/NF‑κB signaling pathway. A TLR4 inhibitor reduced the function of anti‑miR‑146a on inflammation in the model of ALI. Collectively, the results of the present study demonstrated the preventive effects of miR‑146a against severe burn‑induced remote ALI in rats through the anti‑inflammatory‑regulated TLR4/NF‑κB signaling pathway.

Candidate Genes as Biomarkers in Lipopolysaccharide-Induced Acute Respiratory Distress Syndrome Based on mRNA Expression Profile by Next-Generation RNA-Seq Analysis

Up until now, the regulation mechanism at the level of gene during lipopolysaccharide- (LPS-) induced acute respiratory distress syndrome (ARDS) remains unclear. The discovery of differentially expressed genes (DEGs) between LPS-induced ARDS rats and normal rats by next-generation RNA sequencing analysis is of particular interest for the current study. These DEGs may help clinical diagnosis of ARDS and facilitate the selection of the optimal treatment strategy. Randomly, 20 rats were equally divided into 2 groups, the control group and the LPS group. Three rats from each group were selected at random for RNA sequencing analysis. Sequence reads were obtained from Illumina HiSeq4000 and mapped onto the rat reference genome RN6 using Hisat2. We identified 5244 DEGs (Fold_Change > 1.5, and P < 0.05) in the lung tissues from LPS-treated rats compared with normal rats, including 1413 upregulated and 3831 downregulated expressed genes. Lots of chemokine family members were among the most upregulated genes in LPS group. Gene ontology (GO) analysis revealed that almost all of the most enriched and meaningful biological process terms were mainly involved in the functions like immune-inflammation response and the pathways like cytokine-cytokine receptor interaction. We also found that, as for GO molecular function terms, the enriched terms were mainly related to chemokines and cytokines. DEGs with fold change over 100 were verified by quantitative real-time polymerase chain reaction and reanalyzed by gene-gene coexpression network, and the results elucidated central roles of chemokines in LPS-induced ARDS. Our results revealed some new biomarkers for uncovering mechanisms and processes of ARDS.

MicroRNA-146b-3p regulates the development and progression of cerebral infarction with diabetes through RAF1/P38MAPK/COX-2 signaling pathway

Diabetes has been considered as an independent risk factor for cerebral infarction. However, the pathological mechanism of cerebral infarction with diabetes (DMCI) is still rarely known. In this study, we try to explore the relationship between microRNA-146b-3p (miR-146b-3p) and DMCI patients. The peripheral blood mononuclear cells were separated after the patients were selected from our hospital. Firstly, the content of IL-6 and COX-2 was detected by ELISA. Then, the total RNAs were extracted and analyzed by microRNA (miRNA) microarray. Moreover, the target genes of miR-146b-3p were predicted by online miRNA target prediction algorithms. Meanwhile, luciferase reporter system was used for assaying the target gene for miRNA-146b-3p. Simultaneously, RT-PCR assay was used for the miRNA expression detection. Furthermore, western blot was applied to determine the expression of the signal pathway involved proteins. Our results demonstrated that expression of IL-6 and COX-2 were remarkably up-regulated in peripheral blood of DMCI patients compared with that in normal control group. In addition, miRNA microarray data suggested that miR-146b-3p expression was significantly down-regulated in DMCI patients, with v-raf-1 expression negatively regulated. Moreover, miR-146b-3p regulated RAF1 expression was found to mediate P38MAPK signaling activation in thrombosis patients. The following research indicated that activation of RAF1 trough miR-146b-3p down-regulation contributed to activation of RAF/P38MAPK/COX-2 signaling pathway in vascular infarction. Our data have implied that altered expression of miR-146b-3p is closely related to the progression and development of DCMI mediating the RAF/P38MAPK/COX-2 signal transduction pathway.

Anti-inflammatory effect of stem bark of Paulownia tomentosa Steud. in lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages and LPS-induced murine model of acute lung injury

ETHNOPHARMACOLOGICAL RELEVANCE

The leaves, bark, and flowers of Paulownia tomentosa Steud. have been widely used as a traditional medicine in East Asia to treat inflammatory and infectious diseases.

AIM OF THE STUDY

We investigated the protective effect of the methanol stem bark extract of P. tomentosa using an animal model of lipopolysaccharide (LPS)-induced acute lung injury (ALI).

MATERIALS AND METHODS

The UPLC Q-TOF-MS profiles for the methanol extract of P. tomentosa stem bark showed that verbascoside and isoverbascoside were the predominant compounds. Raw 264.7 cells were used for inhibitory effects of cytokine production in vitro. C57BL/6N mice were administered intranasally with LPS (10μg/per mouse) to induce ALI. H&E staining was used to evaluate histological changes in the lung.

RESULTS

Treatment with P. tomentosa stem bark extract (PTBE) suppressed the production of IL-6 and TNF-α in LPS-stimulated RAW 264.7 macrophages, and the recruitment of neutrophils and macrophages in the BALF of mice with LPS-induced ALI. PTBE also decreased the levels of reactive oxygen species (ROS) and pro-inflammatory cytokines in the BALF. PTBE reduced the levels of nitric oxide (NO) in the serum and of inducible nitric oxide synthase (iNOS) in the lung of ALI mice. PTBE also attenuated the infiltration of inflammatory cells and the expression of monocyte chemoattractant protein-1 (MCP-1) in the lung. In addition, PTBE suppressed the activation of NF-κB and the reduced expression of superoxide dismutase 3 (SOD3) in the lung.

CONCLUSION

The results suggest that PTBE has a protective effect on LPS-induced ALI.

ENaCs as Both Effectors and Regulators of MiRNAs in Lung Epithelial Development and Regeneration

Epithelial sodium channels (ENaC) play an important role in re-absorbing excessive luminal fluid by building up an osmotic Na+ gradient across the tight epithelium in the airway, the lung, the kidney, and the colon. The ENaC is a major pathway for retention of salt in kidney too. MicroRNAs (miRs), a group of non-coding RNAs that regulate gene expression at the post-transcriptional level, have emerged as a novel class of regulators for ENaC. Given the ENaC pathway is crucial for maintaining fluid homeostasis in the lung and the kidney and other cavities, we summarized the cross-talk between ENaC and miRs and recapitulated the underlying regulatory factors, including aldosterone, transforming growth factor-β1, and vascular endothelial growth factor-A in the lung and other epithelial tissues/organs. We have compared the profiling of miRs between normal and injured mice and human lungs, which showed a significant alteration in numerous miRs in mouse models of LPS and ventilator induced ARDS. In addition, we reiterated the potential regulation of the ENaC by miRs in stem/ progenitor cell-based re-epithelialization, and identified a promising pharmaceutic target of ENaC for removing edema fluid in ARDS by mesenchymal stem cells-released paracrine. In conclusion, it seems that the interactions between miRs and scnn1s/ENaCs are critical for lung development, epithelial cell turnover in adult lungs, and re-epithelialization for repair.

Macrophages: Their role, activation and polarization in pulmonary diseases

Macrophages, circulating in the blood or concatenated into different organs and tissues constitute the first barrier against any disease. They are foremost controllers of both innate and acquired immunity, healthy tissue homeostasis, vasculogenesis and congenital metabolism. Two hallmarks of macrophages are diversity and plasticity due to which they acquire a wobbling array of phenotypes. These phenotypes are appropriately synchronized responses to a variety of different stimuli from either the tissue microenvironment or - microbes or their products. Based on the phenotype, macrophages are classified into classically activated/(M1) and alternatively activated/(M2) which are further sub-categorized into M2a, M2b, M2c and M2d based upon gene expression profiles. Macrophage phenotype metamorphosis is the regulating factor in initiation, progression, and termination of numerous inflammatory diseases. Several transcriptional factors and other factors controlling gene expression such as miRNAs contribute to the transformation of macrophages at different points in different diseases. Understanding the mechanisms of macrophage polarization and modulation of their phenotypes to adjust to the micro environmental conditions might provide us a great prospective for designing novel therapeutic strategy. In view of the above, this review summarises the activation of macrophages, the factors intricated in activation along with benefaction of macrophage polarization in response to microbial infections, pulmonary toxicity, lung injury and other inflammatory diseases such as chronic obstructive pulmonary dysplasia (COPD), bronchopulmonary dysplasia (BPD), asthma and sepsis, along with the existing efforts to develop therapies targeting this facet of macrophage biology.