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

Hydrogen sulfide plays an important role by regulating microRNA in different ischemia-reperfusion injury

MicroRNAs (miRNAs) are the short endogenous non-coding RNAs that regulate the expression of the target gene at posttranscriptional level through degrading or inhibiting the specific target messenger RNAs (mRNAs). MiRNAs regulate the expression of approximately one-third of protein coding genes, and in most cases inhibit gene expression. MiRNAs have been reported to regulate various biological processes, such as cell proliferation, apoptosis and differentiation. Therefore, miRNAs participate in multiple diseases, including ischemia-reperfusion (I/R) injury. Hydrogen sulfide (H2S) was once considered as a colorless, toxic and harmful gas with foul smelling. However, in recent years, it has been discovered that it is the third gas signaling molecule after carbon monoxide (CO) and nitric oxide (NO), with multiple important biological functions. Increasing evidence indicates that H2S plays a vital role in I/R injury through regulating miRNA, however, the mechanism has not been fully understood. In this review, we summarized the current knowledge about the role of H2S in I/R injury by regulating miRNAs, and analyzed its mechanism in detail.

miR-346 regulates the development of ARDS by regulating the function of pulmonary microvascular endothelial cells

In recent years, many studies have reported that microRNAs play an important role in the pathogenesis of a variety of diseases, and the aim of this paper is to explore the role and mechanism of miR-346 in acute respiratory distress syndrome (ARDS). A mouse model of ARDS was constructed by LPS induction, and RT-qPCR assay was used to verify that the expression level of miR-346 in lung tissue was significantly increased, and was negatively correlated with oxygenation index. Inhibiting the expression of miR-346 in mice and HPMECs by miR-346 inhibitor confirmed that decreased miR-346 expression could lead to increased oxygenation index, decreased lung index, lung water content and NO content to reduce lung injury in mice, while lung inflammation was alleviated and apoptosis was reduced in mice. The same results were obtained in cells. BCL6 was predicted to be a target of miR-346 by targetscan and miRDB; when miR-346 was inhibited, BCL6 expression was increased, and if miR-346 and BCL6 expression were inhibited at the same time, it could aggravate lung injury and reduce the proliferation of HPMECs and increase their apoptosis and inflammation in mice. This shows that miR-346 inhibits the migration of HPMECs by regulating BCL6 expression, which in turn promotes the apoptosis of HPMECs, leading to inflammation and inducing ARDS.

MicroRNA-1 protects the endothelium in acute lung injury

Acute lung injury (ALI) and its most severe form, acute respiratory distress syndrome (ARDS), cause severe endothelial dysfunction in the lung, and vascular endothelial growth factor (VEGF) is elevated in ARDS. We found that the levels of a VEGF-regulated microRNA, microRNA-1 (miR-1), were reduced in the lung endothelium after acute injury. Pulmonary endothelial cell-specific (EC-specific) overexpression of miR-1 protected the lung against cell death and barrier dysfunction in both murine and human models and increased the survival of mice after pneumonia-induced ALI. miR-1 had an intrinsic protective effect in pulmonary and other types of ECs; it inhibited apoptosis and necroptosis pathways and decreased capillary leak by protecting adherens and tight junctions. Comparative gene expression analysis and RISC recruitment assays identified miR-1 targets in the context of injury, including phosphodiesterase 5A (PDE5A), angiopoietin-2 (ANGPT2), CNKSR family member 3 (CNKSR3), and TNF-α-induced protein 2 (TNFAIP2). We validated miR-1-mediated regulation of ANGPT2 in both mouse and human ECs and found that in a 119-patient pneumonia cohort, miR-1 correlated inversely with ANGPT2. These findings illustrate a previously unknown role of miR-1 as a cytoprotective orchestrator of endothelial responses to acute injury with prognostic and therapeutic potential.

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.

Patho-mechanisms of the origins of bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) continues to be one of the most common complications of prematurity, despite significant advancement in neonatology over the last couple of decades. The new BPD is characterized histopathologically by impaired lung alveolarization and dysregulated vascularization. With the increased survival of extremely preterm infants, the risk for the development of BPD remains high, emphasizing the continued need to understand the patho-mechanisms that play a role in the development of this disease. This brief review summarizes recent advances in our understanding of the maldevelopment of the premature lung, highlighting recent research in pathways of oxidative stress-related lung injury, the role of placental insufficiency, growth factor signaling, the extracellular matrix, and microRNAs.

Cytoprotective Peptides from Blue Mussel Protein Hydrolysates: Identification and Mechanism Investigation in Human Umbilical Vein Endothelial Cells Injury

Cardiovascular disease represents a leading cause of mortality and is often characterized by the emergence of endothelial dysfunction (ED), a physiologic condition that takes place in the early progress of atherosclerosis. In this study, two cytoprotective peptides derived from blue mussel chymotrypsin hydrolysates with the sequence of EPTF and FTVN were purified and identified. Molecular mechanisms underlying the cytoprotective effects against oxidative stress which lead to human umbilical vein endothelial cells (HUVEC) injury were investigated. The results showed that pretreatment of EPTF, FTVN and their combination (1:1) in 0.1 mg/mL significantly reduced HUVEC death due to H₂O₂ exposure. The cytoprotective mechanism of these peptides involves an improvement in the cellular antioxidant defense system, as indicated by the suppression of the intracellular ROS generation through upregulation of the cytoprotective enzyme heme oxygenase-1. In addition, H₂O₂ exposure triggers HUVEC damage through the apoptosis process, as evidenced by increased cytochrome C release, Bax protein expression, and the elevated amount of activated caspase-3, however in HUVEC pretreated with peptides and their combination, the presence of those apoptotic stimuli was significantly decreased. Each peptide showed similar cytoprotective effect but no synergistic effect. Taken together, these peptides may be especially important in protecting against oxidative stress-mediated ED.

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.

miR-181c-5p mediates apoptosis of vascular endothelial cells induced by hyperoxemia via ceRNA crosstalk

Oxygen therapy has been widely used in clinical practice, especially in anesthesia and emergency medicine. However, the risks of hyperoxemia caused by excessive O₂ supply have not been sufficiently appreciated. Because nasal inhalation is mostly used for oxygen therapy, the pulmonary capillaries are often the first to be damaged by hyperoxia, causing many serious consequences. Nevertheless, the molecular mechanism by which hyperoxia injures pulmonary capillary endothelial cells (LMECs) has not been fully elucidated. Therefore, we systematically investigated these issues using next-generation sequencing and functional research techniques by focusing on non-coding RNAs. Our results showed that hyperoxia significantly induced apoptosis and profoundly affected the transcriptome profiles of LMECs. Hyperoxia significantly up-regulated miR-181c-5p expression, while down-regulated the expressions of NCAPG and lncRNA-DLEU2 in LMECs. Moreover, LncRNA-DLEU2 could bind complementarily to miR-181c-5p and acted as a miRNA sponge to block the inhibitory effect of miR-181c-5p on its target gene NCAPG. The down-regulation of lncRNA-DLEU2 induced by hyperoxia abrogated its inhibition of miR-181c-5p function, which together with the hyperoxia-induced upregulation of miR-181c-5p, all these significantly decreased the expression of NCAPG, resulting in apoptosis of LMECs. Our results demonstrated a ceRNA network consisting of lncRNA-DLEU2, miR-181c-5p and NCAPG, which played an important role in hyperoxia-induced apoptosis of vascular endothelial injury. Our findings will contribute to the full understanding of the harmful effects of hyperoxia and to find ways for effectively mitigating its deleterious effects.

Diverse Effects of Exosomes on COVID-19: A Perspective of Progress From Transmission to Therapeutic Developments

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a new strain of coronavirus and the causative agent of the current global pandemic of coronavirus disease 2019 (COVID-19). There are currently no FDA-approved antiviral drugs for COVID-19 and there is an urgent need to develop treatment strategies that can effectively suppress SARS-CoV-2 infection. Numerous approaches have been researched so far, with one of them being the emerging exosome-based therapies. Exosomes are nano-sized, lipid bilayer-enclosed structures, share structural similarities with viruses secreted from all types of cells, including those lining the respiratory tract. Importantly, the interplay between exosomes and viruses could be potentially exploited for antiviral drug and vaccine development. Exosomes are produced by virus-infected cells and play crucial roles in mediating communication between infected and uninfected cells. SARS-CoV-2 modulates the production and composition of exosomes, and can exploit exosome formation, secretion, and release pathways to promote infection, transmission, and intercellular spread. Exosomes have been exploited for therapeutic benefits in patients afflicted with various diseases including COVID-19. Furthermore, the administration of exosomes loaded with immunomodulatory cargo in combination with antiviral drugs represents a novel intervention for the treatment of diseases such as COVID-19. In particular, exosomes derived from mesenchymal stem cells (MSCs) are used as cell-free therapeutic agents. Mesenchymal stem cell derived exosomes reduces the cytokine storm and reverse the inhibition of host anti-viral defenses associated with COVID-19 and also enhances mitochondrial function repair lung injuries. We discuss the role of exosomes in relation to transmission, infection, diagnosis, treatment, therapeutics, drug delivery, and vaccines, and present some future perspectives regarding their use for combating COVID-19.

Genome-wide landscape of mRNAs, microRNAs, lncRNAs, and circRNAs in hemorrhagic shock-induced ALI/ARDS in rats

BACKGROUND

Hemorrhagic shock (HS) can develop into multiple organ dysfunction syndrome, among which acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) usually lead to poor outcomes. The underlying molecular mechanisms of HS-induced ALI/ARDS remain unclear. This study sought to investigate gene expression profiles and predict competing endogenous RNA (ceRNA) regulatory networks in an HS-induced ALI/ARDS preclinical model.

METHODS

Sprague Dawley rats were subjected to a fixed volume of hemorrhage (HS, 40% estimated total blood volume) or not (sham) randomly. After 8 hours of observation, left lung tissue was harvested to evaluate lung injury. Right lung was collected for RNA sequencing. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analyses were performed and the long noncoding RNA (lncRNA)/circular RNA (circRNA)-microRNA (miRNA)-messenger RNA (mRNA) linkages were predicted using the ceRNA theory. Quantitative real-time polymerase chain reaction was used to validate the RNA sequencing findings.

RESULTS

Hemorrhagic shock lungs showed noticeable ALI/ARDS features, and 437 mRNAs, 31 miRNAs, 734 lncRNAs, and 29 circRNAs were differentially expressed. In Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analyses, the differentially expressed transcripts were enriched in the following terms: the metabolic pathways, signal transduction pathways, necroptosis, DNA damage recognition and repair, inflammatory cell migration and chemotaxis, the NOD-like receptor signaling pathway, the Janus kinase/signal transducer and activator of transcription signaling pathway, the mitogen-activated protein kinase signaling pathway, the phosphatidylinositol-3-kinase/protein kinase B signaling pathway, and so on. Also, this study identified lncRNA-miRNA-mRNA linkages with 12 lncRNAs, 5 miRNAs, 15 mRNAs, and circRNA-miRNA-mRNA linkages with 10 circRNAs, 16 miRNAs, 39 mRNAs. These networks might play important regulatory roles.

CONCLUSION

This is the first high-throughput analysis of gene expression profiles in HS-induced ALI/ARDS. It shows that metabolism, cell signaling, DNA damage and repair, and necroptosis-related RNAs altered, and inflammatory response-associated RNAs and pathways have pivotal roles in HS-induced ALI/ARDS progression. It also prompts some important RNAs and regulatory networks for future research.

LEVEL OF EVIDENCE

Basic science article.

SREBF2 triggers endoplasmic reticulum stress and Bax dysregulation to promote lipopolysaccharide-induced endothelial cell injury

An increased lipopolysaccharide (LPS) level in patients with cirrhosis induced the dysregulation of sterol regulatory element-binding transcription factor 2 (SREBF2), which participated in the modulation of tumor inflammatory microenvironment. However, the role of SREBF2 in the LPS-induced injury of portal vein endothelium was scarcely reported. This study aimed to investigate the effects of SREBF2 on the LPS-induced injury to endothelial cells (ECs) in vitro and in vivo and explore the underlying mechanism. In this study, we found that LPS increased SREBF2 expression through activating the TLR4/JNK/c-Jun pathway and suppressed UBE2I-mediated SREBF2 sumoylation to enhance its transcriptional activity. The dysregulation of SREBF2 induced ER stress by increasing the intracellular cholesterol level and facilitated Bax expression to cause additional damage to LPS-induced ECs. As a potential intervention, miR590-3p negatively regulated SREBF2 expression and upregulated UBE2I expression by targeting TLR4, thus alleviating LPS-induced injury. These results suggest that LPS-induced SREBF2 triggered ER stress and promoted Bax expression to injure ECs, which was reversed by miR590-3p. The mechanisms of SREBF2 mediated LPS-induced endothelial injury of portal vein, which might be the therapeutic target for PVT development in cirrhosis patients. 1. LPS promoted SREBF2 expression by activating the TLR4/JNK/c-Jun pathway and suppressed UBE2I-mediated SREBF2 sumoylation to upregulate SREBF2 transcriptional activity 2. SREBF2-mediated ER stress and Bax expression involved in LPS-induced EC injury 3. miR590-3p decreased SREBF2 expression by targeting TLR4 and mitigated LPS-induced EC injury.

Deregulated miRNA expression is associated with endothelial dysfunction in post-mortem lung biopsies of COVID-19 patients

MicroRNAs (miRNAs) are critical modulators of endothelial homeostasis, which highlights their involvement in vascular diseases, including those caused by virus infections. Our main objective was to identify miRNAs involved in the endothelial function and determine their expression in post-mortem lung biopsies of COVID-19 patients with severe respiratory injuries and thrombotic events. Based on functional enrichment analysis, miR-26a-5p, miR-29b-3p, and miR-34a-5p were identified as regulators of mRNA targets involved in endothelial and inflammatory signaling pathways, as well as viral diseases. A miRNA/mRNA network, constructed based on protein-protein interactions of the miRNA targets and the inflammatory biomarkers characterized in the patients, revealed a close interconnection of these miRNAs in association to the endothelial activation/dysfunction. Reduced expression levels of selected miRNAs were observed in the lung biopsies of COVID-19 patients (n = 9) compared to the Controls (n = 10) (P < 0.01-0.0001). MiR-26a-5p and miR-29b-3p presented the best power to discriminate these groups (area under the curve (AUC) = 0.8286, and AUC = 0.8125, respectively). The correlation analysis of the miRNAs with inflammatory biomarkers in the COVID-19 patients was significant for miR-26a-5p [IL-6 (r2 = 0.5414), and ICAM-1 (r2 = 0.5624)], and miR-29b-3p [IL-4 (r2 = 0.8332) and IL-8 (r2 = 0.2654)]. Altogether, these findings demonstrate the relevance and the non-random involvement of miR-26a-5p, miR-29b-3p, and miR-34a-5p in endothelial dysfunction and inflammatory response in patients with SARS-CoV-2 infection and the occurrence of severe lung injury and immunothrombosis.

MicroRNA-574-5p Attenuates Acute Respiratory Distress Syndrome by Targeting HMGB1

Acute respiratory distress syndrome (ARDS) is a critical condition with high mortality. HMGB1 (high-mobility group protein B1) is one of the key proinflammatory factors in the ARDS “inflammatory storm.” According to previous studies, some microRNAs (miRNAs) play important roles in this process. We aimed to determine the contributing miRNAs targeting the expression and release of HMGB1. miRNA expression in the peripheral blood of patients with ARDS was measured by miRNA microarray. miRNAs targeting HMGB1 were screened and explored for further study. In LPS-induced cell and mouse ARDS models, we explored the effect of this miRNA on the expression and secretion of HMGB1 by Western blot, real-time qPCR, and ELISA. The effects of this miRNA on the NF-κB signaling pathway, proinflammatory cytokines, and NLRP3 (nod-like receptor protein 3) inflammasome were detected by Western blot and real-time qPCR. In ARDS models, microRNA-574-5p (miR-574-5p) expression could be induced by the TLR4/NF-κB pathway upon LPS stimulation. It could suppress the inflammatory response by targeting HMGB1. Enforcing the expression of miR-574-5p or HMGB1 siRNA silencing inhibits the activation of NF-κB signaling pathway and the NLRP3 inflammasome. Moreover, overexpression of HMGB1 reversed the antiinflammatory effect of miR-574-5p. In ARDS mice, overexpression of miR-574-5p suppresses alveolar leukocytes infiltration, interstitial edema, protein effusion, and inflammation. This study demonstrated that miR-574-5p provided negative feedback to LPS-induced inflammation and relieved ARDS. It may provide new therapeutic strategies for ARDS.

SIRT1-Related Signaling Pathways and Their Association With Bronchopulmonary Dysplasia

Bronchopulmonary dysplasia (BPD) is a chronic and debilitating disease that can exert serious and overwhelming effects on the physical and mental health of premature infants, predominantly due to intractable short- and long-term complications. Oxidative stress is one of the most predominant causes of BPD. Hyperoxia activates a cascade of hazardous events, including mitochondrial dysfunction, uncontrolled inflammation, reduced autophagy, increased apoptosis, and the induction of fibrosis. These events may involve, to varying degrees, alterations in SIRT1 and its associated targets. In the present review, we describe SIRT1-related signaling pathways and their association with BPD. Our intention is to provide new insights into the molecular mechanisms that regulate BPD and identify potential therapeutic targets for this debilitating condition.

Apoptosis in resistance arteries induced by hydrogen peroxide: greater resilience of endothelium versus smooth muscle

Reactive oxygen species (ROS) are implicated in cardiovascular and neurologic disorders including atherosclerosis, heart attack, stroke, and traumatic brain injury. Although oxidative stress can lead to apoptosis of vascular cells, such findings are largely based upon isolated vascular smooth muscle cells (SMCs) and endothelial cells (ECs) studied in culture. Studying intact resistance arteries, we have focused on understanding how SMCs and ECs in the blood vessel wall respond to acute oxidative stress induced by hydrogen peroxide, a ubiquitous, membrane-permeant ROS. We find that apoptosis induced by H₂O₂ is far greater in SMCs compared to ECs. For both cell types, apoptosis is associated with a rise in intracellular calcium concentration ([Ca²⁺]_i) during H₂O₂ exposure. Consistent with their greater death, the rise in [Ca²⁺]_i for SMCs exceeds that in ECs. Finding that disruption of the endothelium increases SMC death, we address how myoendothelial coupling and paracrine signaling attenuate apoptosis. Remarkably, conditions associated with chronic oxidative stress (advanced age, Western-style diet) protect SMCs during H₂O₂ exposure, as does female sex. In light of intracellular Ca²⁺ handling, we consider how glycolytic versus oxidative pathways for ATP production and changes in mitochondrial structure and function impact cellular resilience to H₂O₂-induced apoptosis. Gaining new insight into protective signaling within and between SMCs and ECs of the arterial wall can be applied to promote vascular cell survival (and recovery of blood flow) in tissues subjected to acute oxidative stress as occurs during reperfusion following myocardial infarction and thrombotic stroke.

C1q/tumor necrosis factor-related protein-6 attenuates TNF-α-induced apoptosis in salivary acinar cells via AMPK/SIRT1-modulated miR-34a-5p expression

C1q/tumor necrosis factor-related protein-6 (CTRP6) is a newly identified adipokine involved in diverse biological processes. However, its role in salivary glands remains unknown. Here, we demonstrated that CTRP6 was mainly distributed in the nuclei, apicolateral membranes, and cytoplasm of human submandibular glands (SMGs), serous cells of parotid glands, and ducts and apicolateral membranes of serous cells in rats and mice. CTRP6 inhibited the apoptosis rate and reversed the increased levels of cleaved caspase 3, caspase 8, caspase 9, and cytochrome C and the decreased Bcl-2 expression induced by tumor necrosis factor (TNF)-α in both SMG-C6 cells and cultured human SMG tissues. Microarray analysis identified 43 differentially expressed microRNAs (miRNAs) in the SMGs of nonobese diabetic mice. miR-34a-5p was selected due to its upregulation by TNF-α, which was abolished by CTRP6. The miR-34a-5p inhibitor promoted whereas the miR-34a-5p mimic suppressed the effects of CTRP6 on TNF-α-induced apoptosis. CTRP6 increased AMP-activated protein kinase (AMPK) phosphorylation and reversed TNF-α-induced SIRT1 downregulation in salivary cells. AraA, an AMPK inhibitor, reversed the effects of CTRP6 on TNF-α-induced alterations in the levels of SIRT1, miR-34a-5p, Bcl-2, and cleaved caspase 3 in vitro and ex vivo, whereas activating AMPK by AICAR reversed the decrease in SIRT1 expression and increase in miR-34a-5p expression induced by TNF-α. Inhibition of SIRT1 by EX527 suppressed the effects of CTRP6 on TNF-α-induced changes in miR-34a-5p and apoptosis-related proteins. Our findings indicate that salivary glands are novel sites for CTRP6 synthesis and secretion. CTRP6 protects acinar cells against TNF-α-induced apoptosis via AMPK/SIRT1-modulated miR-34a-5p expression.

MiR-34a-5p and miR-452-5p: The Novel Regulators of Pancreatic Endocrine Dysfunction in Diabetic Zucker Rats?

Objective: The pancreatic endocrinal system dominates the regulation of blood glucose levels in vivo, and the dysfunction of pancreatic endocrine β-cells is a major cause of the occurrence and development of Type 2 diabetes (T2D). Although microRNA (miRNA) have been found to be key regulators of pancreatic β-cells proliferation, differentiation and apoptosis, the underlying mechanism remains enigmatic. The aim of this study was to identify several novel miRNAs which might be involved in the etiopathogenesis of diabetic β-cells dysfunction. Methods: The miRNA expression profiles in the pancreas of high-fat diet (HFD) fed Zucker diabetic fatty (ZDF) rats and Zucker lean (ZL) rats feed with normal-fat diet (NFD) were detected by using miRNA microarray chip, and individually verified the most significant factors by quantitative real-time polymerase chain reaction (qRT-PCR) assay. The Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were used to predict the target genes related to each of the identified miRNAs and the functions of these target genes in different metabolic signaling pathways. Results: Compared with the ZL rats, a total of 24 differentially expressed miRNAs were detected in ZDF rats. Among which miR-34a-5p and miR-452-5p were the most significantly up-regulated and down-regulated respectively. These miRNAs have not been reported in rats' pancreas before. By GO and KEGG enrichment analyses, we found that miR-34a-5p could negatively regulate pancreatic β-cell proliferation through the involvement of Wnt signaling pathway. In addition, it was also found to regulate insulin secretion through the insulin signaling pathway to modulate blood glucose levels. At the same time, miR-452-5p was found to positively regulate the activity of the key rate-limiting enzyme branched-chain α-keto acid dehydrogenase-β (BCKDHB) in the catabolism of branched chain amino acids (BCAA), leading to mitochondrial dysfunction in pancreatic β-cells. Conclusions: miR-34a-5p and miR-452-5p were identified as the novel regulators of pancreatic endocrine dysfunction. These miRNAs might have the potential to be utilized as the new predictive biomarkers for the diagnosis of the occurrence and development of T2D, as well as the therapeutic targets for T2D treatment.

Sestrin 2 protects against LPS-induced acute lung injury by inducing mitophagy in alveolar macrophages

AIMS

Acute lung injury (ALI) / acute respiratory distress syndrome (ARDS) is a critical clinical syndrome with complex pathology and pathogenesis. Since there is no specific treatment for ALI, it is important to study the mechanism of how ALI develop. Sestrin2 (Sesn2) plays a critical role in the regulation of cellular stress response and oxidant defense. However, the potential function of Sesn2 in ALI/ARDS and the associated mechanism remains unclear.

MAIN METHODS

Lipopolysaccharide (LPS) induced ALI model was performed in the wild-type and Sesn2 knockout (Sesn2-/-) mice. The nod-like receptor protein 3 (NLRP3) inflammasome, cell pyroptosis and mitophagy were detected by western blots, immunofluorescent staining, flow cytometry. Lung injury were measured by histopathology and electron microscopy.

KEY FINDINGS

Knockout of Sesn2 enhanced LPS-induced ALI. As detailed in Sesn2^-/- mice, NLRP3 inflammasome and cell pyroptosis were increased in lungs; IL-1β and IL-18 in serum and bronchoalveolar lavage fluid (BALF) were further promoted; In the isolated alveolar macrophages from Sesn2-/- mice, mitophagy induced by LPS was markedly inhibited, while reactive oxygen species (ROS), mitochondrial damage and cell pyroptosis were enhanced. Knocking down or overexpressing Sensn2 in J774.A1 cells demonstrated Sesn2 promoted Sequestosome1 (SQSTM1) expression and mitophagy by PTEN-induced putative kinase 1 (Pink1)/Parkin pathway.

SIGNIFICANCE

Sesn2 protected ALI by promoting mitophagy that exerts protection of AMs pyroptosis and negative regulation of NLRP3 inflammasomes. These data indicated Sesn2 might be a potential target for ALI treatment.

Association of Exosomal miR-34a with Markers of Dyslipidemia and Endothelial Dysfunction in Children and Adolescents with T1DM

OBJECTIVE

Dyslipidemia and endothelial dysfunction are common disorders and major causative factors for atherosclerosis in patients with type 1 diabetes mellitus (T1DM). However, their pathophysiology in young patients with T1DM is still under evaluated. We aimed, for the first time, to assess the expression of exosomal micro-RNA 34a (miR-34a) in serum of children and adolescents with T1DM and correlate this expression with markers of dyslipidemia and endothelial dysfunction.

METHODS

The study included 120 T1DM patients and 100 control subjects. Assessment of miR-34a was performed using quantitative real-time polymerase chain reaction. Lipid profile was assessed on an automated analyzer and serum endoglin and intracellular adhesion molecule (ICAM) concentrations were measured using immunometric methods.

RESULTS

Relative expression of miR-34a and serum endoglin and ICAM concentrations were higher in patients than controls (p=0.001) and in patients with dyslipidemia (42 patients) compared to patients without dyslipidemia (78 patients) (p=0.01). Linear regression analysis revealed a strong independent association between exosomal miR-34a expression and total cholesterol, low-density lipoprotein, serum endoglin and serum ICAM after adjustment for other cofactors. The utility of miR-34a as an indicator for associated dyslipidemia was tested using receiver operator characteristic curve analysis which revealed area under the curve: 0.73 with confidence interval: 0.63-0.83 and p=0.001.

CONCLUSION

This was the first study to show the altered expression of exosomal miR-34a among children and adolescents with T1DM. Moreover, association of miR-34a with markers of dyslipidemia and endothelial dysfunction was identified, suggesting that it could play a role in regulation of lipid metabolism and endothelial function in T1DM.

Apigenin induces apoptosis and counteracts cisplatin-induced chemoresistance via Mcl-1 in ovarian cancer cells

Ovarian cancer (OC) is one of the prominent causes of mortality in female patients diagnosed with gynecologic malignancies. While it has previously been demonstrated that apigenin inhibits cell growth in colon and breast cancer cells, the effect of apigenin in OC cells is not fully understood. Therefore, the aim of the present study was to investigate the impact of apigenin on cell death and resistance to cisplatin in OC cells. It was found that apigenin inhibited proliferation, hindered cell cycle progression and promoted SKOV3 cell apoptosis. Moreover, these effects were also observed in cisplatin-resistant SKOV3/DDP cells. Furthermore, apigenin reduced the mitochondrial transmembrane potential, and elevated the ratios of cleaved caspase-3/caspase-3 and Bax/Bcl-2 in the two cell types. Reverse transcription-quantitative PCR and western blotting results demonstrated that apigenin significantly downregulated Mcl-1 at the transcriptional and translational levels in SKOV3 and SKOV3/DDP cells, which was responsible for its cytotoxic functions and chemosensitizing effects. Collectively, the present results identified the impact of apigenin on OC cell death and resistance to cisplatin, and the potential molecular mechanisms. However, additional studies are required to further elucidate the underlying mechanisms.

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-122-5p protects against acute lung injury via regulation of DUSP4/ERK signaling in pulmonary microvascular endothelial cells

AIMS

The aim of this study was to explore the role of miR-122-5p in acute lung injury.

MATERIALS AND METHODS

Mice were subjected to intratracheal injection of lipopolysaccharide to establish an acute lung injury model. The mice also received miR-122-5p antagonist and mimic via injection to inhibit or overexpress miR-122-5p in the lung tissue, respectively. In an in vitro experiment, we isolated primary mouse lung microvascular endothelial cells and established a cell injury model via lipopolysaccharide treatment.

KEY FINDINGS

Mice injected with an miR-122-5p antagonist exhibited reduced lung injury, inflammation and oxidative stress, while mice injected with a miR-122-5p mimic exhibited exaggerated lung injury, inflammation and oxidative stress. In an in vitro experiment, we found that the miR-122-5p antagonist suppressed lipopolysaccharide-induced inflammation, apoptosis and oxidative stress. Moreover, miR-122-5p regulated the promoter activity of DUSP4, which negatively regulated ERK1/2 signaling. The use of DUSP4 siRNA counteracted the effects of the miR-122-5p antagonist.

SIGNIFICANCE

Taken together, these results show that miR-122-5p protected against acute lung injury via regulation of DUSP4/ERK signaling in pulmonary microvascular endothelial cells. MiR-122-5p antagonism may be a promising treatment method for acute lung injury.

Inhibition of microRNA-451 is associated with increased expression of Macrophage Migration Inhibitory Factor and mitgation of the cardio-pulmonary phenotype in a murine model of Bronchopulmonary Dysplasia

Background

Macrophage migration inhibitory factor (MIF) has been implicated as a protective factor in the development of bronchopulmonary dysplasia (BPD) and is known to be regulated by MicroRNA-451 (miR-451). The aim of this study was to evaluate the role of miR-451 and the MIF signaling pathway in in vitro and in vivo models of BPD.

Methods

Studies were conducted in mouse lung endothelial cells (MLECs) exposed to hyperoxia and in a newborn mouse model of hyperoxia-induced BPD. Lung and cardiac morphometry as well as vascular markers were evaluated.

Results

Increased expression of miR-451 was noted in MLECs exposed to hyperoxia and in lungs of BPD mice. Administration of a miR-451 inhibitor to MLECs exposed to hyperoxia was associated with increased expression of MIF and decreased expression of angiopoietin (Ang) 2. Treatment with the miR-451 inhibitor was associated with improved lung morphometry indices, significant reduction in right ventricular hypertrophy, decreased mean arterial wall thickness and improvement in vascular density in BPD mice. Western blot analysis demonstrated preservation of MIF expression in BPD animals treated with a miR-451 inhibitor and increased expression of vascular endothelial growth factor-A (VEGF-A), Ang1, Ang2 and the Ang receptor, Tie2.

Conclusion

We demonstrated that inhibition of miR-451 is associated with mitigation of the cardio-pulmonary phenotype, preservation of MIF expression and increased expression of several vascular growth factors.

Plasma exosomal miRNAs involved in endothelial injury in microscopic polyangiitis patients

Microscopic polyangiitis (MPA) is a systemic autoimmune disease that primarily affects the small and medium blood vessels. Endothelial injury is one of the pathological hallmarks of MPA. However, the pathogenesis for this has not yet been fully elucidated. Exosomal microRNAs (miRNAs) have recently emerged as a new molecular pattern involved in the endothelial injury in other diseases. Hence, we speculated that MPA plasma-derived exosomes (MPA-exo) could induce the endothelial injury, which was likely to be aroused by the dysregulated exosomal miRNAs in MPA. In the present study, plasma-derived exosomes were isolated and identified. MPA-exo could be internalized by human renal glomerular endothelial cells (HRGECs) in vitro and induced HRGECs injury. Subsequently, a series of differentially expressed miRNAs in MPA-exo were identified by high-throughput sequencing analysis. Further bioinformatics analysis for the target genes of these differentially expressed miRNAs showed a potential mechanism for their possible role in MPA endothelial injury. Notably, we revealed a considerable correlation between miR-185-3p, miR-125a-3p, and clinical parameters. In conclusion, the current study revealed that differentially expressed miRNAs in MPA-exo are associated with the endothelial injury. Our results suggested that these miRNAs and their target genes might be involved in the inflammation process of MPA.

Novel noncoding RNAs biomarkers in acute respiratory distress syndrome

Introduction: Acute respiratory distress syndrome (ARDS) is a very common condition associated with critically ill patients, which causes substantial morbidity and mortality. Currently, there is no effective clinical ARDS treatment strategy. Novel targets that effectively treat ARDS need to be found.Areas covered: Data sources were published articles through June 2019 in PubMed using the following keywords: 'acute respiratory distress syndrome,' 'miRNAs,' 'lncRNAs,' and 'biomarkers.' The selection of studies focused on in cellular model, animal model, and clinical studies of ARDS.Expert commentary: Accumulated evidence revealed that some specific miRNAs and lncRNAs could regulate the signaling pathways of the pathophysiology by targeting specific molecule in ARDS. The differentially expressed miRNAs exert a crucial role in apoptosis of neutrophil, antigen-presenting cells and lung epithelial cell, and the dysfunction of mitochondrial. Recently, the influence of lncRNAs upon miRNA function is also rapidly emerging. In some cases, lncRNA MALAT1 target TLR4 to mediate the p38 MAPK and NF-κB signaling pathway in ARDS rat model. In other cases, lncRNA CASC2 was found to act as a ceRNA of miR-144-3p which directly targeted AQP1 in LPS-induced A549 cell. In addition, other miRNA-lncRNA regulatory patterns in ARDS and novel biomarkers still require deeper research.

Adiponectin deficiency induces mitochondrial dysfunction and promotes endothelial activation and pulmonary vascular injury

Adiponectin (APN), an adipocyte-derived adipokine, has been shown to limit lung injury originating from endothelial cell (EC) damage. Previously we reported that obese mice with low circulatory APN levels exhibited pulmonary vascular endothelial dysfunction. This study was designed to investigate the cellular and molecular mechanisms underlying the pulmonary endothelium-dependent protective effects of APN. Our results demonstrated that in APN-/- mice, there was an inherent state of endothelium mitochondrial dysfunction that could contribute to endothelial activation and increased susceptibility to LPS-induced acute lung injury (ALI). We noted that APN-/- mice showed decreased expression of mitochondrial biogenesis regulatory protein peroxisome proliferator-activated receptor γ coactivator 1-α (PGC-1α) and its downstream proteins nuclear respiratory factor 1, transcription factor A, mitochondrial, and Sirtuin (Sirt)3 and Sirt1 expression in whole lungs and in freshly isolated lung ECs from these mice at baseline and subjected to LPS-induced ALI. We further showed that treating APN-/- mice with PGC-1α activator pyrroloquinoline quinone enhances mitochondrial biogenesis and function in lung endothelium and attenuation of ALI. These results suggest that the pulmonary endothelium-protective properties of APN are mediated, at least in part, by an enhancement of mitochondrial biogenesis through a mechanism involving PGC-1α activation.-Shah, D., Torres, C., Bhandari, V. Adiponectin deficiency induces mitochondrial dysfunction and promotes endothelial activation and pulmonary vascular injury.