Restoring microRNA-499-5p Protects Sepsis-Induced Lung Injury Mice Via Targeting Sox6

Mechanisms of Qingyi Decoction in Severe Acute Pancreatitis-Associated Acute Lung Injury via Gut Microbiota: Targeting the Short-Chain Fatty Acids-Mediated AMPK/NF-κB/NLRP3 Pathway

The pivotal roles of gut microbiota in severe acute pancreatitis-associated acute lung injury (SAP-ALI) are increasingly revealed, and recent discoveries in the gut-lung axis have provided potential approaches for treating SAP-ALI. Qingyi decoction (QYD), a traditional Chinese medicine (TCM), is commonly used in clinical to treat SAP-ALI. However, the underlying mechanisms remain to be fully elucidated. Herein, by using a caerulein plus lipopolysaccharide (LPS)-induced SAP-ALI mice model and antibiotics (Abx) cocktail-induced pseudogermfree mice model, we tried to uncover the roles of the gut microbiota by administration of QYD and explored its possible mechanisms. Immunohistochemical results showed that the severity of SAP-ALI and intestinal barrier functions could be affected by the relative depletion of intestinal bacteria. The composition of gut microbiota was partially recovered after QYD treatment with decreased Firmicutes/Bacteroidetes ratio and increased relative abundance in short-chain fatty acids (SCFAs)-producing bacteria. Correspondingly increased levels of SCFAs (especially propionate and butyrate) in feces, gut, serum, and lungs were observed, generally consistent with changes in microbes. Western-blot analysis and RT-qPCR results indicated that the AMPK/NF-κB/NLRP3 signaling pathway was activated after oral administration of QYD, which was found to be possibly related to the regulatory effects on SCFAs in the intestine and lungs. In conclusion, our study provides new insights into treating SAP-ALI through modulating the gut microbiota and has prospective practical value for clinical use in the future. IMPORTANCE Gut microbiota affects the severity of SAP-ALI and intestinal barrier function. During SAP, a significant increase in the relative abundance of gut pathogens (Escherichia, Enterococcus, Enterobacter, Peptostreptococcus, Helicobacter) was observed. At the same time, QYD treatment decreased pathogenic bacteria and increased the relative abundance of SCFAs-producing bacteria (Bacteroides, Roseburia, Parabacteroides, Prevotella, Akkermansia). In addition, The AMPK/NF-κB/NLRP3 pathway mediated by SCFAs along the gut-lung axis may play an essential role in preventing the pathogenesis of SAP-ALI, which allows for reduced systemic inflammation and restoration of the intestinal barrier.

HIV-1 gp120 protein promotes HAND through the calcineurin pathway activation

For over two decades, highly active antiretroviral therapy (HAART) was able to help prolong the life expectancy of people living with HIV-1 (PLWH) and eliminate the virus to an undetectable level. However, an increased prevalence of HIV- associated neurocognitive disorders (HAND) was observed. These symptoms range from neuronal dysfunction to cell death. Among the markers of neuronal deregulation, we cite the alteration of synaptic plasticity and neuronal communications. Clinically, these dysfunctions led to neurocognitive disorders such as learning alteration and loss of spatial memory, which promote premature brain aging even in HAART-treated patients. In support of these observations, we showed that the gp120 protein deregulates miR-499-5p and its downstream target, the calcineurin (CaN) protein. The gp120 protein also promotes the accumulation of calcium (Ca2+) and reactive oxygen species (ROS) inside the neurons leading to the activation of CaN and the inhibition of miR-499-5p. gp120 protein also caused mitochondrial fragmentation and changes in shape and size. The use of mimic miR-499 restored mitochondrial functions, appearance, and size. These results demonstrated the additional effect of the gp120 protein on neurons through the miR-499-5p/calcineurin pathway.

Identification of ferroptosis-related genes in male mice with sepsis-induced acute lung injury based on transcriptome sequencing

BACKGROUND

Sepsis can result in acute lung injury (ALI). Studies have shown that pharmacological inhibition of ferroptosis can treat ALI. However, the regulatory mechanisms of ferroptosis in sepsis-induced ALI remain unclear.

METHODS

Transcriptome sequencing was performed on lung tissue samples from 10 sepsis-induced mouse models of ALI and 10 control mice. After quality control measures, clean data were used to screen for differentially expressed genes (DEGs) between the groups. The DEGs were then overlapped with ferroptosis-related genes (FRGs) to obtain ferroptosis-related DEGs (FR-DEGs). Subsequently, least absolute shrinkage and selection operator (Lasso) and Support Vector Machine-Recursive Feature Elimination (SVM-RFE) were used to obtain key genes. In addition, Ingenuity Pathway Analysis (IPA) was employed to explore the disease, function, and canonical pathways related to the key genes. Gene set enrichment analysis (GSEA) was used to investigate the functions of the key genes, and regulatory miRNAs of key genes were predicted using the NetworkAnalyst and StarBase databases. Finally, the expression of key genes was validated with the GSE165226 and GSE168796 datasets sourced from the Gene Expression Omnibus (GEO) database and using quantitative real-time polymerase chain reaction (qRT-PCR).

RESULTS

Thirty-three FR-DEGs were identified between 1843 DEGs and 259 FRGs. Three key genes, Ncf2, Steap3, and Gclc, were identified based on diagnostic models established by the two machine learning methods. They are mainly involved in infection, immunity, and apoptosis, including lymphatic system cell migration and lymphocyte and T cell responses. Additionally, the GSEA suggested that Ncf2 and Steap3 were similarly enriched in mRNA processing, response to peptides, and leukocyte differentiation. Furthermore, a key gene-miRNA network including 2 key genes (Steap3 and Gclc) and 122 miRNAs, and a gene-miRNA network with 1 key gene (Steap3) and 3 miRNAs were constructed using NetworkAnalyst and StarBase, respectively. Both databases predicted that mmu-miR-15a-5p was the target miRNA of Steap3. Finally, Ncf2 expression was validated using both datasets and qRT-PCR, and Steap3 was validated using GSE165226 and qRT-PCR.

CONCLUSIONS

This study identified two FR-DEGs (Ncf2 and Steap3) associated with sepsis-induced ALI via transcriptome analyses, as well as their functional and metabolic pathways.

Effect of miR-499-5p/SOX6 axis on atrial fibrosis in rats with atrial fibrillation

Atrial fibrosis is involved in the progression of atrial fibrillation (AF). miR-499-5p is the most downregulated microRNA in arrhythmogenic cardiomyopathy hearts. Sry-related high-mobility-group box 6 (SOX6) is associated with apoptosis, inflammatory responses, and fibrosis. This study investigated the mechanism of miR-499-5p in ameliorating AF rats by regulating SOX6. AF rat models were established by injecting Ach-CaCl₂ mixture, and the rats were treated with Lv-miR-499-5p/oe-SOX6/si-SOX6 before modeling. AF duration was recorded using electrocardiogram. miR-499-5p and SOX6 expression levels in the myocardium were determined by reverse transcription-quantitative polymerase chain reaction. The binding of miR-499-5p and SOX6 was validated. The atrial fibrosis degree and cardiomyocyte apoptosis were assessed using the Masson and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling staining methods. Levels of SOX6, atrial fibrosis markers (collage I/α-SMA/TGFβ1), cell cycle-related proteins (p21/CDC25/Cyclin B1), and cell senescence markers (SA-β-gal/γ-H2AX) were measured using Western blotting and immunohistochemistry. miR-499-5p was downregulated and SOX6 was upregulated in AF rats. miR-499-5p overexpression shortened the AF duration, alleviated atrial fibrosis, and decreased collage I/α-SMA/TGFβ1. miR-499-5p targeted SOX6 to ameliorate atrial fibrosis. AF rats exhibited increased p21/CDC25/Cyclin B1/SA-β-gal/γ-H2AX levels and raised cardiomyocyte apoptosis. SOX6 silencing downregulated p21 and alleviated cardiomyocyte cycle arrest, cell senescence, and apoptosis in AF rats. Shortly, miR-499-5p suppresses atrial fibrosis and cardiomyocyte senescence by targeting SOX6 and downregulating p21, thus mitigating AF in rats.

Deregulated RNAs involved in sympathetic regulation of sepsis-induced acute lung injury based on whole transcriptome sequencing

Sympathetic nerves play essential roles in the regulation of lung inflammation, and we investigated the effect of sympathetic denervation (SD) on sepsis-induced acute lung injury (ALI) in mice. Mice were randomized to the control, SD, ALI and SD + ALI, groups. SD and ALI were established through intratracheal 6-hydroxydopamine and intraperitoneal lipopolysaccharide, respectively. Models and gene expressions levels were evaluated by HE staining, ELISA, Western blotting and RT-qPCR. RNA extraction, whole transcriptome sequencing and subsequent biostatistical analysis were performed. Sympathetic denervation in the lungs significantly attenuated lung TNF-ɑ and norepinephrine expression, alleviated sepsis-induced acute lung injury and inhibited NF-κB signaling. Compared with the ALI group, the SD + ALI group exhibited 629 DE circRNAs, 269 DE lncRNAs,7 DE miRNAs and 186 DE mRNAs, respectively. Some DE RNAs were validated by RT-qPCR. CircRNA-miRNA-mRNA regulatory networks in the SD + ALI group revealed enrichment of the B-cell receptor signaling pathway, IL-17 signaling pathway, neuroactive ligand-receptor interaction, CAM, primary immunodeficiency, and cytokine-cytokine receptor interaction terms. The lncRNA-miRNA-mRNA network also revealed inflammation-related signaling pathways. Taken together, based on the successfully established models of SD and ALI, we show here that sympathetic nerves may regulate sepsis-induced ALI supposedly by affecting the expression of circRNAs, lncRNAs, miRNAs, and mRNAs in the lungs. These results may allow for further exploration of the roles of pulmonary sympathetic nerves in sepsis-induced ALI.

Expression of MicroRNAs in Sepsis-Related Organ Dysfunction: A Systematic Review

Sepsis is a critical condition characterized by increased levels of pro-inflammatory cytokines and proliferating cells such as neutrophils and macrophages in response to microbial pathogens. Such processes lead to an abnormal inflammatory response and multi-organ failure. MicroRNAs (miRNA) are single-stranded non-coding RNAs with the function of gene regulation. This means that miRNAs are involved in multiple intracellular pathways and thus contribute to or inhibit inflammation. As a result, their variable expression in different tissues and organs may play a key role in regulating the pathophysiological events of sepsis. Thanks to this property, miRNAs may serve as potential diagnostic and prognostic biomarkers in such life-threatening events. In this narrative review, we collect the results of recent studies on the expression of miRNAs in heart, blood, lung, liver, brain, and kidney during sepsis and the molecular processes in which they are involved. In reviewing the literature, we find at least 122 miRNAs and signaling pathways involved in sepsis-related organ dysfunction. This may help clinicians to detect, prevent, and treat sepsis-related organ failures early, although further studies are needed to deepen the knowledge of their potential contribution.

Combination of azithromycin and methylprednisolone alleviates Mycoplasma pneumoniae induced pneumonia by regulating miR‑499a‑5p/STAT3 axis

Mycoplasma pneumoniae (M. pneumoniae) is a contributing factor to community-acquired pneumonia in children. The present study sought to explain the underlying mechanism of azithromycin (AZM) combined with methylprednisolone (MP) in the treatment of M. pneumoniae infection. Peripheral blood samples were obtained from patients with M. pneumoniae and healthy volunteers for analysis. A549 cells were infected with M. pneumoniae to construct an in vitro cell model with M. pneumoniae, followed by treatment with AZM and MP. Cell Counting Kit-8 and TUNEL assays were conducted to detect cell viability and apoptosis. RT-qPCR was employed to measure the expression levels of microRNA (miR)-499a-5p and STAT3. Western blotting was performed to measure the expression of STAT3 and apoptosis-related proteins. Luciferase report assay was performed to verify the binding site between miR-499a-5p and STAT3. The production of inflammatory cytokines was determined using ELISA kits. The results exhibited the downregulated miR-499a-5p and dysregulated inflammatory cytokines in peripheral blood of patients and M. pneumoniae-infected A549 cells. AZM and MP treatment alone or combined significantly inhibited inflammatory response, cell viability loss and promoted apoptosis in A549 cells infected with M. pneumoniae, which was partly reversed by inhibition of miR-499a-5p. Furthermore, miR-499a-5p could negatively regulate its direct target STAT3. In addition, STAT3 is also regulated by AZM and MP. Collectively, the present results suggested that combination treatment of AZM and MP could inhibit M. pneumoniae infection-induced inflammation, cell viability loss and promoted apoptosis partly by regulating miR-499a-5p/STAT3 axis.

Crosstalk of pyroptosis, ferroptosis, and mitochondrial aldehyde dehydrogenase 2-related mechanisms in sepsis-induced lung injury in a mouse model

Acute lung injury (ALI) is a common complication of sepsis. Mitochondrial aldehyde dehydrogenase 2 (ALDH2), an enzyme involved in aldehyde metabolism, exerts a protective effect against sepsis. This study investigated the possible mechanisms underlying the roles of ALDH2, pyroptosis, and ferroptosis in sepsis-induced lung injury. A mouse model of sepsis-induced lung injury was established by cecal ligation and puncture (CLP); lung morphology was evaluated by calculation of lung coefficient, hematoxylin–eosin staining, and electron microscopy. Malondialdehyde (MDA), reactive oxygen species (ROS), and 4-hydroxy-2-nonenal (4-HNE) protein expression levels were used to detect the level of lipid oxidative stress. In addition, total iron was detected using an iron detection kit, and the expression of ferroptosis-related proteins (PTGS2, GPX4), pyroptosis-related proteins, and ALDH2 was examined using western blotting. To further examine the likely mechanisms, the ferroptosis inhibitor ferrostatin 1 (Fer-1), NLRP3 inflammasome inhibitor MCC950, and ALDH2 activator Alda-1 were added. CLP-treated mice exhibited destruction of lung tissue morphology, lipid peroxidation injury, iron content, and increased lung PTGS2 protein expression, accompanied by a decrease in GPX4 protein expression. CLP also downregulated ALDH2 expression and increased the expression of the NLRP3 inflammasome and pyroptosis-related proteins. These adverse effects of CLP were relieved by Alda-1, Fer-1, and MCC950 treatment. In conclusion, both pyroptosis and ferroptosis participate in CLP-induced ALI, and ALDH2 plays a protective role by reducing pyroptosis and ferroptosis. This study provides a scientific basis for the treatment of lung injury in sepsis.

miR-155: A Potential Biomarker for Predicting Mortality in COVID-19 Patients

COVID-19, a pandemic of severe acute respiratory syndrome caused by Coronavirus 2 (SARS-CoV-2), continues to pose diagnostic and therapeutic challenges due to its unpredictable clinical course. Prognostic biomarkers may improve care by enabling quick identification of patients who can be safely discharged home versus those who may need careful respiratory monitoring and support. MicroRNAs (miRNAs) have risen to prominence as biomarkers for many disease states and as tools to assist in medical decisions. In the present study, we aimed to examine circulating miRNAs in hospitalized COVID-19 patients and to explore their potential as biomarkers for disease severity. We studied, by quantitative PCR, the expressions of miR-21, miR-146a, miR-146b, miR-155, and miR-499 in peripheral blood. We found that mild COVID-19 patients had 2.5-fold less circulating miR-155 than healthy people, and patients with a severe COVID-19 disease had 5-fold less circulating miR-155 than healthy people. In addition, we found that miR-155 is a good predictor of COVID-19 mortality. We suggest that examining miR-155 levels in patients' blood, upon admission to hospital, will ameliorate the care given to COVID-19 patients.

Predictive value and regulatory mechanism of serum miR-499a-5p on myocardial dysfunction in sepsis

Background

This study sought to investigate the predictive value and regulatory mechanism of serum miR-499a-5p in sepsis-induced myocardial dysfunction (SIMD).

Methods

A total of 60 patients with sepsis and 60 healthy volunteers were enrolled in this study. The serum levels of miRNAs (miR-451, miR-378 and miR-499a-5p) were detected. Receiver operating characteristic curve and logistic regression analysis were used to evaluate the diagnostic and prognostic value of miR-499a-5p in SIMD patients. AC16 cells were used to establish SIMD model in vitro using lipopolysaccharide (LPS). An analysis was conducted for miR-499a-5p expression, cell viability, and the concentration of creatine kinase-MB isoform (CK-MB), brain natriuretic peptide (BNP), superoxide dismutase (SOD) and cytochrome C oxidase IV (COX IV). The downstream target of miR-499a-5p was verified.

Results

Our results revealed a poor expression of miR-499a-5p in the serum of SIMD patients, while no significant difference was evident for miR-451 and miR-378. The level of miR-499a-5p in the survival group was higher than the non-survival group. miR-499a-5p elicited good diagnostic and prognostic value for SIMD. Our findings revealed that miR-499a-5p was decreased significantly in LPS-treated cardiomyocytes. After overexpression of miR-499a-5p, the cell viability increased, and the concentrations of CK-MB and BNP were decreased, while the concentrations of SOD and COX IV were increased. EIF4E was validated as the target of miR-499a-5p. After overexpression of EIF4E, the cell viability was decreased and the concentrations of CK-MB and BNP were increased while the concentrations of SOD and COX IV were decreased.

Conclusion

The level of miR-499a-5p is weak in SIMD patients. miR-499a-5p has a good diagnostic and prognostic value for SIMD by inhibiting EIF4E transcription.