MicroRNA-142-3p and let-7g Negatively Regulates Augmented IL-6 Production in Neonatal Polymorphonuclear Leukocytes

The critical role of miRNA in bacterial zoonosis

The public's health and the financial sustainability of international societies remain threatened by bacterial zoonoses, with limited reliable diagnostic and therapeutic options available for bacterial diseases. Bacterial infections influence mammalian miRNA expression in host-pathogen interactions. In order to counteract bacterial infections, miRNAs participate in gene-specific expression and play important regulatory roles that rely on translational inhibition and target gene degradation by binding to the 3' non-coding region of target genes. Intriguingly, according to current studies, that exogenous miRNAs derived from plants could potentially serve as effective medicinal components sourced from traditional Chinese medicine plants. These exogenous miRNAs exhibit stable functionality in mammals and mimic the regulatory roles of endogenous miRNAs, illuminating the molecular processes behind the therapeutic effects of plants. This review details the immune defense mechanisms of inflammation, apoptosis, autophagy and cell cycle disturbance caused by some typical bacterial infections, summarizes the role of some mammalian miRNAs in regulating these mechanisms, and introduces the cGAS-STING signaling pathway in detail. Evidence suggests that this newly discovered immune defense mechanism in mammalian cells can also be affected by miRNAs. Meanwhile, some examples of transboundary regulation of mammalian mRNA and even bacterial diseases by exogenous miRNAs from plants are also summarized. This viewpoint provides fresh understanding of microbial tactics and host mechanisms in the management of bacterial illnesses.

Diminished miR-374c-5p negatively regulates IL (interleukin)-6 in unexplained recurrent spontaneous abortion

Unexplained recurrent spontaneous abortion (URSA) is commonly observed, and seriously affects women's reproductive health. Excessive interleukin-6 (IL-6) production has been shown to frequently occur and relate to URSA pathogenesis. In this study, the miRNA expression profile in peripheral blood mononuclear cells (PBMCs) from URSA patients and normal pregnant (NP) women was assessed by miRNA microarray and real-time quantitative reverse-transcription polymerase chain reaction (qPCR). MiRNA target prediction tools and luciferase reporter assay were used to detect direct binding between miRNAs and IL6. Functional study of administering anti-IL-6 neutralizing antibody and miR-374c-5p mimics to an URSA animal model was performed to evaluate embryo resorption rates. In the results, compared with NP women, the expression of IL-6 increased markedly in PBMCs and decidual tissues at both mRNA and protein levels, while miR-374c-5p expression decreased significantly. Prediction software and luciferase reporter assay showed that miR-374c-5p binds with IL6 3'UTR via the complementary bases. Transfection of miR-374c-5p mimics into an in vitro HeLa cell line significantly downregulated the expression of IL-6, while transfection of the miR-374c-5p inhibitor induced an opposite result. In the URSA mouse model, miR-374c-5p overexpression reduced the embryo resorption rate significantly, accompanied with decreased expression of IL-6 in the decidua. To sum up, downregulated miR-374c-5p was involved in the pathogenesis of URSA by enhancing IL-6 expression. Modulation of miR-374c-5p expression may be used to regulate IL-6 production for the treatment of URSA.

Detection of SARS-CoV-2 infection by microRNA profiling of the upper respiratory tract

Host biomarkers are increasingly being considered as tools for improved COVID-19 detection and prognosis. We recently profiled circulating host-encoded microRNA (miRNAs) during SARS-CoV-2 infection, revealing a signature that classified COVID-19 cases with 99.9% accuracy. Here we sought to develop a signature suited for clinical application by analyzing specimens collected using minimally invasive procedures. Eight miRNAs displayed altered expression in anterior nasal tissues from COVID-19 patients, with miR-142-3p, a negative regulator of interleukin-6 (IL-6) production, the most strongly upregulated. Supervised machine learning analysis revealed that a three-miRNA signature (miR-30c-2-3p, miR-628-3p and miR-93-5p) independently classifies COVID-19 cases with 100% accuracy. This study further defines the host miRNA response to SARS-CoV-2 infection and identifies candidate biomarkers for improved COVID-19 detection.

Plasma cell-free RNA characteristics in COVID-19 patients

The pathogenesis of COVID-19 is still elusive, which impedes disease progression prediction, differential diagnosis, and targeted therapy. Plasma cell-free RNAs (cfRNAs) carry unique information from human tissue and thus could point to resourceful solutions for pathogenesis and host-pathogen interactions. Here, we performed a comparative analysis of cfRNA profiles between COVID-19 patients and healthy donors using serial plasma. Analyses of the cfRNA landscape, potential gene regulatory mechanisms, dynamic changes in tRNA pools upon infection, and microbial communities were performed. A total of 380 cfRNA molecules were up-regulated in all COVID-19 patients, of which seven could serve as potential biomarkers (AUC > 0.85) with great sensitivity and specificity. Antiviral (NFKB1A, IFITM3, and IFI27) and neutrophil activation (S100A8, CD68, and CD63)–related genes exhibited decreased expression levels during treatment in COVID-19 patients, which is in accordance with the dynamically enhanced inflammatory response in COVID-19 patients. Noncoding RNAs, including some microRNAs (let 7 family) and long noncoding RNAs (GJA9-MYCBP) targeting interleukin (IL6/IL6R), were differentially expressed between COVID-19 patients and healthy donors, which accounts for the potential core mechanism of cytokine storm syndromes; the tRNA pools change significantly between the COVID-19 and healthy group, leading to the accumulation of SARS-CoV-2 biased codons, which facilitate SARS-CoV-2 replication. Finally, several pneumonia-related microorganisms were detected in the plasma of COVID-19 patients, raising the possibility of simultaneously monitoring immune response regulation and microbial communities using cfRNA analysis. This study fills the knowledge gap in the plasma cfRNA landscape of COVID-19 patients and offers insight into the potential mechanisms of cfRNAs to explain COVID-19 pathogenesis.

Epigenetic regulation of pediatric and neonatal immune responses

Epigenetic regulation of transcription is a collective term that refers to mechanisms known to regulate gene transcription without changing the underlying DNA sequence. These mechanisms include DNA methylation and histone tail modifications which influence chromatin accessibility, and microRNAs that act through post-transcriptional gene silencing. Epigenetics is known to regulate a variety of biological processes, and the role of epigtenetics in immunity and immune-mediated diseases is becoming increasingly recognized. While DNA methylation is the most widely studied, each of these systems play an important role in the development and maintenance of appropriate immune responses. There is clear evidence that epigenetic mechanisms contribute to developmental stage-specific immune responses in a cell-specific manner. There is also mounting evidence that prenatal exposures alter epigenetic profiles and subsequent immune function in exposed offspring. Early life exposures that are associated with poor long-term health outcomes also appear to impact immune specific epigenetic patterning. Finally, each of these epigenetic mechanisms contribute to the pathogenesis of a wide variety of diseases that manifest during childhood. This review will discuss each of these areas in detail. IMPACT: Epigenetics, including DNA methylation, histone tail modifications, and microRNA expression, dictate immune cell phenotypes. Epigenetics influence immune development and subsequent immune health. Prenatal, perinatal, and postnatal exposures alter immune cell epigenetic profiles and subsequent immune function. Numerous pediatric-onset diseases have an epigenetic component. Several successful strategies for childhood diseases target epigenetic mechanisms.

MicroRNA as an Early Biomarker of Neonatal Sepsis

Sepsis is a major cause of lethality in neonatal intensive care units. Despite significant advances in neonatal care and growing scientific knowledge about the disease, 4 of every 10 infants born in developed countries and suffering from sepsis die or experience considerable disability, including substantial and permanent neurodevelopmental impairment. Pharmacological treatment strategies for neonatal sepsis remain limited and mainly based upon early initiation of antibiotics and supportive treatment. In this context, numerous clinical and serum-based markers have been evaluated for diagnosing sepsis and evaluating its severity and etiology. MicroRNAs (miRNAs) do not encode for proteins but regulate gene expression by inhibiting the translation or transcription of their target mRNAs. Recently, it was demonstrated in adult patients that miRNAs are released into the circulation and that the spectrum of circulating miRNAs is altered during various pathologic conditions, such as inflammation, infection, and sepsis. Here, we summarize current findings on the role of circulating miRNAs in the diagnosis and staging of neonatal sepsis. The conclusions point to substantial diagnostic potential, and several miRNAs have been validated independently by different teams, namely miR-16a, miR-16, miR-96-5p, miR-141, miR-181a, and miR-1184.

Clinical and immunological aspects of microRNAs in neonatal sepsis

Neonatal sepsis constitutes a highly relevant public health challenge and is the most common cause of infant morbidity and mortality worldwide. Recent studies have demonstrated that during infection epigenetic changes may occur leading to reprogramming of gene expression. Post-transcriptional regulation by short non-coding RNAs (e.g., microRNAs) have recently acquired special relevance because of their role in the regulation of the pathophysiology of sepsis and their potential clinical use as biomarkers. ~22-nucleotide of microRNAs are not only involved in regulating multiple relevant cellular and molecular functions, such as immune cell function and inflammatory response, but have also been proposed as good candidates as biomarkers in sepsis. Nevertheless, establishing clinical practice guidelines based on microRNA patterns as biomarkers for diagnosis and prognosis in neonatal sepsis has yet to be achieved. Given their differential expression across tissues in neonates, the release of specific microRNAs to blood and their expression pattern can differ compared to sepsis in adult patients. Further in-depth research is necessary to fully understand the biological relevance of microRNAs and assess their potential use in clinical settings. This review provides a general overview of microRNAs, their structure, function and biogenesis before exploring their potential clinical interest as diagnostic and prognostic biomarkers of neonatal sepsis. An important part of the review is focused on immune and inflammatory aspects of selected microRNAs that may become biomarkers for clinical use and therapeutic intervention.

The Functional DNA Methylation Signatures Relevant to Altered Immune Response of Neonatal T Cells with l-Arginine Supplementation

l-Arginine is an important nutrient in the infant diet that significantly regulates the maturation of the immune system in neonates, including the maturation of CD4⁺ T cells. The biological activities of CD4⁺ T cells differ substantially between neonates and adults, and these differences may be governed by epigenetic processes. Investigating these differences and the causative processes may help understand neonatal and developmental immunity. In this study, we compared the functional DNA methylation profiles in CD4⁺ T cells of neonates and adults, focusing on the role of l-arginine supplementation. Umbilical cord blood and adult CD4⁺ T cells were cultured with/without l-arginine treatment. By comparing DNA methylation in samples without l-arginine treatment, we found that CD4⁺ T cells of neonatal cord blood generally showed higher DNA methylation than those of adults (average CpG methylation percentage 0.6305 for neonate and 0.6254 for adult, t-test p-value < 0.0001), suggesting gene silencing in neonates. By examining DNA methylation patterns of CpG dinucleotides induced by l-arginine treatment, we found that more CpG dinucleotides were hypomethylated and more genes appeared to be activated in neonatal T-cells as compared with adult. Genes activated by l-arginine stimulation of cord blood samples were more enriched regarding immune-related pathways. CpG dinucleotides at IL-13 promoter regions were hypomethylated after l-arginine stimulation. Hypomethylated CpG dinucleotides corresponded to higher IL-13 gene expression and cytokine production. Thus, DNA methylation partially accounts for the mechanism underlying differential immune function in neonates. Modulatory effects of l-arginine on DNA methylation are gene-specific. Nutritional intervention is a potential strategy to modulate immune function of neonates.

Interleukin‑6 signalling as a valuable cornerstone for molecular medicine (Review)

The biological abilities of interleukin-6 (IL-6) have been under investigation for nearly 40 years. IL-6 works through an interaction with the complex peptide IL-6 receptor (IL-6R). IL-6 is built with four α-chain nanostructures, while two different chains, IL-6Rα (gp80) and gp130/IL6β (gp130), are included in IL-6R. The three-dimensional shapes of the six chains composing the IL-6/IL-6R complex are the basis for the nanomolecular roles of IL-6 signalling. Genes, pseudogenes and competitive endogenous RNAs of IL-6 have been identified. In the present review, the roles played by miRNA in the post-transcriptional regulation of IL-6 expression are evaluated. mRNAs are absorbed via the 'sponge' effect to dynamically balance mRNA levels and this has been assessed with regard to IL-6 transcription efficiency. According to current knowledge on molecular and nanomolecular structures involved in active IL-6 signalling, two different IL-6 models have been proposed. IL-6 mainly has functions in inflammatory processes, as well as in cognitive activities. Furthermore, the abnormal production of IL-6 has been found in patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2; also known as COVID-19). In the present review, both inflammatory and cognitive IL-6 models were analysed by evaluating the cytological and histological locations of IL-6 signalling. The goal of this review was to illustrate the roles of the classic and trans-signalling IL-6 pathways in endocrine glands such as the thyroid and in the central nervous system. Specifically, autoimmune thyroid diseases, disorders of cognitive processes and SARS-CoV-2 virus infection have been examined to determine the contribution of IL-6 to these disease states.

Downregulation of miR-1184 serves as a diagnostic biomarker in neonatal sepsis and regulates LPS-induced inflammatory response by inhibiting IL-16 in monocytes

Neonatal sepsis (NS) remains a global problem. In the present study, abnormal expression of microRNA-1184 (miR-1184) was detected in neonates with NS and it was endeavored to investigate the diagnostic value of miR-1184, as well as its regulatory role in lipopolysaccharide (LPS)-induced inflammatory response in vitro. Furthermore, the correlation between interleukin-16 (IL-16) and miR-1184 was investigated to elucidate the pathological mechanisms of NS development. Reverse transcription-quantitative PCR was used to detect the expression of miR-1184. Receiver operating characteristic curve analysis was performed to evaluate the diagnostic value of miR-1184 in NS. Furthermore, a sepsis cell model was established by using LPS-induced monocytes to explore the effect of miR-1184 on the inflammatory response. The levels of inflammatory cytokines were determined by ELISA. A luciferase reporter assay was used to investigate the direct targeting interaction between miR-1184 and IL-16. The results indicated that the serum levels of miR-1184 in neonates with sepsis were decreased and miR-1184 had a high diagnostic value when differentiating NS from respiratory conditions in neonates. In vitro, the expression of miR-1184 in monocytes was inhibited by LPS and overexpression of miR-1184 reversed the effect of LPS to stimulate the inflammatory response. IL-16 was demonstrated to be a target of miR-1184 and a negative correlation between them was identified in patients with NS. The inflammatory response inhibited by miR-1184 mimics was enhanced by overexpression of IL-16 in LPS-induced monocytes. In conclusion, decreased levels of serum miR-1184 may be a potential diagnostic biomarker for NS. In addition, miR-1184 inhibited the LPS-induced inflammatory response by targeting IL-16 in monocytes, suggesting that the miR-1184/IL-16 axis may be a potential therapeutic target for NS.

Outer Membrane Vesicles Derived from Klebsiella pneumoniae Influence the miRNA Expression Profile in Human Bronchial Epithelial BEAS-2B Cells

Klebsiella pneumoniae is an opportunistic pathogen that causes nosocomial and community-acquired infections. The spread of resistant strains of K. pneumoniae represents a growing threat to human health, due to the exhaustion of effective treatments. K. pneumoniae releases outer membrane vesicles (OMVs). OMVs are a vehicle for the transport of virulence factors to host cells, causing cell injury. Previous studies have shown changes of gene expression in human bronchial epithelial cells after treatment with K. pneumoniae OMVs. These variations in gene expression could be regulated through microRNAs (miRNAs), which participate in several biological mechanisms. Thereafter, miRNA expression profiles in human bronchial epithelial cells were evaluated during infection with standard and clinical K. pneumoniae strains. Microarray analysis and RT-qPCR identified the dysregulation of miR-223, hsa-miR-21, hsa-miR-25 and hsa-let-7g miRNA sequences. Target gene prediction revealed the essential role of these miRNAs in the regulation of host immune responses involving NF-ĸB (miR-223), TLR4 (hsa-miR-21), cytokine (hsa-miR-25) and IL-6 (hsa-let-7g miRNA) signalling pathways. The current study provides the first large scale expression profile of miRNAs from lung cells and predicted gene targets, following exposure to K. pneumoniae OMVs. Our results suggest the importance of OMVs in the inflammatory response.

Let-7g* and miR-98 Reduce Stroke-Induced Production of Proinflammatory Cytokines in Mouse Brain

Stroke is a debilitating illness facing healthcare today, affecting over 800,000 people and causing over 140,000 deaths each year in the United States. Despite being the third-leading cause of death, very few treatments currently exist for stroke. Often, during an ischemic attack, the blood-brain barrier (BBB) is significantly damaged, which can lead to altered interactions with the immune system, and greatly worsen the damage from a stroke. The impaired, BBB promotes the infiltration of peripheral inflammatory cells into the brain, secreting deleterious mediators (cytokines/chemokines) and resulting in permanent barrier injury. let-7 microRNAs (miRs) are critical for regulating immune responses within the BBB, particularly after ischemic stroke. We have previously shown how transient stroke decreases expression of multiple let-7 miRs, and that restoration of expression confers significant neuroprotection, reduction in brain infiltration by neutrophils, monocytes and T cells. However, the specific mechanisms of action of let-7 miRs remain unexplored, though emerging evidence implicates a range of impacts on cytokines. In the current study, we evaluate the impacts of miR-98 and let-7g* on targeting of cytokine mRNAs, cytokine release following ischemic stroke, and cell-specific changes to the neurovascular space. We determined that miR-98 specifically targets IP-10, while let-7g* specifically aims IL-8, and attenuates their levels. Both produce strong impacts on CCL2 and CCL5. Further, let-7g* strongly improves neurovascular perfusion following ischemic stroke. Together, the results of the study indicate that let-7 miRs are critical for mediating endothelial-immune reactions and improving recovery following ischemic stroke.

MicroRNA-142-3p attenuates hepatic ischemia/reperfusion injury via targeting of myristoylated alanine-rich C-kinase substrate

MiR-142-3p as one key molecule in oncogenesis and inflammation plays crucial roles in hepatic fibrosis, hepatocellular carcinoma and other liver disease. However, there have no literatures to report its effects on hepatic ischemia-reperfusion (HI/R) injury. In the present work, hypoxia reoxygenation (H/R) models on AML12 and HepG2 cells, and ischemia/reperfusion model in mice were established. The methods of real-time PCR, dual luciferase reporter, mimic, inhibitor, agomir, antagomir and siRNA transfection assays were used. The expression levels of miR-142-3p were decreased in model groups in vitro and in vivo compared with control group or Sham group, which directly targeted MARCKS to regulate its expression. Then, MARCKS activated p38/JNK signal, up-regulated NF-κB expression to accelerate inflammation, and inhibited PI3K/AKT signal to promote apoptosis. Moreover, miR-142-3p mimic in vitro and agomir in vivo lowered the expression levels of MARCKS, thereby alleviating apoptosis and inflammation to relieve HI/R injury. Furthermore, miR-142- 3p inhibitor in vitro and antagomir in vivo up-regulated the expression levels of MARCKS to aggravate HI/R damage via promoting inflammation and apoptosis. Consistently, MARCKS siRNA markedly inhibited HI/R injury by restraining apoptosis and inflamm- ation in mice. MiR-142-3p played a considerable part in adjusting HI/R injury by targeting MARCKS, and miR-142-3p/MARCKS should be a new therapeutic target for HI/R injury.

ADAR1 Alleviates Inflammation in a Murine Sepsis Model via the ADAR1-miR-30a-SOCS3 Axis

Adenosine deaminase acting on double-stranded RNA 1 (ADAR1) mediates adenosine-to-inosine (A-to-I) RNA editing events. ADAR1 is highly expressed in “septic” macrophages and in small intestinal tissues of mice with sepsis. Overexpression of ADAR1 suppresses inflammation and intestinal damage. However, the specific underlying mechanism is unclear. This study was conducted to explore how microRNA (miRNA) regulates the anti-inflammatory mechanism of macrophages following ADAR1 upregulation. A murine sepsis model was established by cecal ligation and puncture (CLP). Mice were randomly assigned to sham, CLP, and CLP+ADAR1 groups. Hematoxylin and eosin (HE) staining and fluorescence isothiocyanate-dextran were used to evaluate intestinal injury and permeability. Quantitative reverse transcription-polymerase chain reaction (qRT-PCR), western blotting, and Luminex assays were performed to detect changes in the expression of inflammatory cytokines. Adenoviruses were used to express ADAR1 in RAW 264.7 cells. Ribonucleoprotein immunoprecipitation analysis was conducted to detect the binding of ADAR1 and miRNAs. A dual-luciferase reporter assay was used to detect the binding of miRNAs and regulatory factors. We observed that ADAR1 significantly increased the expression of suppressor of cytokine signaling 3 (SOCS3) in macrophages and reduced the expression of interleukin-6 in macrophages and the serum, thereby reducing intestinal permeability and mucosal injury in mice with sepsis. The RNA-ribonucleoprotein immunoprecipitation binding assay and qRT-PCR demonstrated a direct interaction between ADAR1 and pri-miR-30a. The luciferase assay demonstrated that SOCS3 was significantly inhibited by miR-30a-5p, the mature product of miR-30a. Thus, ADAR1 exerts a protective effect against sepsis by reducing inflammation and organ damage via the ADAR1-miR-30a-SOCS3 axis.

Neutrophil extracellular trap-enriched supernatants carry microRNAs able to modulate TNF-α production by macrophages

Neutrophil extracellular traps (NETs) emerge from the cell as a DNA scaffold associated with cytoplasmic and granular proteins, able to immobilize and kill pathogens. This association occurs following nuclear and granular membrane disintegration, allowing contact with the decondensed chromatin. Thus, it is reasonable to speculate that the DNA can also mix with miRNAs and carry them in NETs. Here, we report for the first time the presence of the miRNA carriers associated with NETs and miRNAs present in NET-enriched supernatants (NET-miRs), thus adding a novel class of molecules and new proteins that can be released and transported in the NET platform. We observed that the majority of NET-miRs were common to all four stimuli used (PMA, interleukin-8, amyloid fibrils and Leishmania), and that miRNA-142-3p carried by NETs down-modulates protein kinase Cα and regulates TNF-α production in macrophages upon NET interaction with these cells. Our findings unveil a novel role for NETs in the cell communication processes, allowing the conveyance of miRNA from neutrophils to neighboring cells.

MicroRNA let-7g-5p alleviates murine collagen-induced arthritis by inhibiting Th17 cell differentiation

Rheumatoid arthritis (RA) is a chronic and systemic autoimmune disease with complicated pathogenesis. IL-17-producing T helper cells (Th17) are important players in the RA process. Despite numerous researches have proven that microRNAs (miRNAs) are crucial to regulate autoimmune diseases including RA, the effect of miRNAs on Th17 cell differentiation and function in the RA progress is not clear. Here, our results showed that the expression of miRNA let-7g-5p was substantially lower in RA patients and CIA mice compared with healthy controls, accompanied by the increased Th17 cell population. Furthermore, the inhibition of let-7g-5p on Th17 cell differentiation and function were verified in vitro. Notably, the disease severity in CIA mice was significantly alleviated after the treatment of let-7g-5p mimics. In addition, let-7g-5p mimics treatment markedly down-regulated the frequency of Th17 cells in CIA mice. Taken together, our findings indicate that let-7g-5p can ameliorate CIA through blocking the differentiation of Th17 cells, which may be a novel strategy to treat autoimmune diseases such as RA.

Biological Roles of Neutrophil-Derived Granule Proteins and Cytokines

Neutrophils, the most abundant white blood cells in human circulation, entertain intense interactions with other leukocyte subsets, platelets, and stromal cells. Molecularly, such interactions are typically communicated through proteins generated during granulopoiesis, stored in granules, or produced on demand. Here, we provide an overview of the mammalian regulation of granule protein production in the bone marrow and the de novo synthesis of cytokines by neutrophils recruited to tissues. In addition, we discuss some of the known biological roles of these protein messengers, and how neutrophil-borne granule proteins and cytokines can synergize to modulate inflammation and tumor development. Decoding the neutrophil interactome is important for therapeutically neutralizing individual proteins to putatively dampen inflammation, or for delivering modified neutrophil-borne proteins to boost host defense.

LIN28B/let-7 axis mediates pulmonary inflammatory response induced by diesel exhaust particle exposure in mice

Exposure to diesel exhaust particle (DEP) is closely related to inflammatory response in respiratory system. To understand the underlying molecular mechanism by which DEP induces pulmonary inflammatory response, we conducted DEP exposure experiments in vivo and in vitro. In vivo, each mouse was exposed to DEP suspension (100 μg of DEP) or vehicle only once in single intra-tracheal instillation (IT) section, or was exposed to DEP suspension (12.5 μg or 50 μg of DEP) or vehicle 12 times in repeated IT section. DEP exposure induced significant pathological injuries with substantial neutrophils infiltration and the increased level of pro-inflammatory cytokine IL-6 in mouse lungs. Consistently, elevated IL6 mRNA level was also observed in DEP treatment group (100 μg/ml) in vitro. In addition, DEP exposure exerted the similar influence on the expression of let-7d and let-7g microRNAs in vivo and in vitro. To verify the possible role of LIN28B/let-7 axis in the regulation of IL6 expression following DEP exposure, we applied RNAi technology in vitro, and found increased IL6 mRNA expression was alleviated or neutralized in DEP exposure groups after LIN28B silencing or after let-7d or let-7g over-expression. Taken together, we conclude that LIN28B/let-7 axis might be involved in inflammatory response induced by DEP exposure.

LncRNA SNHG16 reverses the effects of miR-15a/16 on LPS-induced inflammatory pathway

Nowadays, neonatal sepsis has gradually become a global problem for its high incidence and increasing mortality. Previous studies have reported that miR-15a and miR-16 are two important modulators in neonatal sepsis. However, the upstream molecular mechanism of miR-15a/16 cluster is still mysterious. This study aims to explore a lncRNA can bind with miR-15a/16 in neonatal sepsis. Microarray analysis helped us found top ten lncRNAs which were downregulated in neonatal sepsis serum. Among these ten lncRNAs, SNHG16 was uncovered to significantly downregulated both miR-15a and miR-16. According to the result of subcellular fractionation assay, SNHG16 was mainly located in the cytoplasm of RAW264.7 cell, indicating the potential ceRNA role of SNHG16. Mechanism investigations revealed that SNHG16 could act as a ceRNA to upregulate TLR4 which is the target mRNA of miR-15a/16 cluster. At last, rescue assays demonstrated that SNHG16 reversed the effects of miR-15a/16 on LPS-induced inflammatory pathway. In summary, SNHG16 can act as a ceRNA to modulate miR-15a/16 cluster, thereby affecting LSP-induced inflammatory pathway which was downregulated by miR-15a/16 cluster.

Circulating microRNA expression profiling and bioinformatics analysis of dysregulated microRNAs of patients with coronary artery disease

MicroRNs (miRNAs) are small non-coding RNAs that modulate the expression of protein-coding genes at the post-transcription level and their dysregulated expression has been implicated in cardiovascular diseases. Circulating miRNAs have been widely recommended as potential biomarkers for many diseases including coronary artery disease. In this study, the miRNA expression profiles of 6 normal coronary artery (NCA), 12 patients with coronary artery disease including 6 unstable angina (UA) patients and 6 ST-segment elevation myocardial infarction (STEMI) patients were determined by small RNA sequencing. The differential expression of miRNAs was verified via using quantitative reverse transcription polymerase chain reaction (qRT-PCR). We further performed bioinformatics analysis for the differentially expressed miRNAs. The results showed that 60 miRNAs were up-regulated and 26 miRNAs were down-regulated in the UA group and 49 miRNAs were up-regulated and 62 miRNAs were down-regulated in the UA group when compared with the NCA group. Among them, both of UA group and STEMI group shared 38 dysregulated miRNAs (28 up-regulated and 10 down-regulated) versus NCA group. ROC curves analysis showed that miR-142-3p and miR-17-5p might server as potential biomarkers for the detection and diagnosis of UA and STEMI. Bioinformatics functional predictions showed that the differential expressed miRNAs were closely related with the pathological process of coronary artery disease. We comprehensively analyzed profile expression of circulating miRNAs of patients with coronary artery disease. Our study suggested that miR-142-3p and miR-17-5p might be potential targets for follow-up research in evaluating biomarkers of coronary artery disease.

Expression profiling of microRNAs in human bone tissue from postmenopausal women

Bone tissue is composed of several cell types, which express their own microRNAs (miRNAs) that will play a role in cell function. The set of total miRNAs expressed in all cell types configures the specific signature of the bone tissue in one physiological condition. The aim of this study was to explore the miRNA expression profile of bone tissue from postmenopausal women. Tissue was obtained from trabecular bone and was analyzed in fresh conditions (n = 6). Primary osteoblasts were also obtained from trabecular bone (n = 4) and human osteoclasts were obtained from monocyte precursors after in vitro differentiation (n = 5). MicroRNA expression profiling was obtained for each sample by microarray and a global miRNA analysis was performed combining the data acquired in all the microarray experiments. From the 641 miRNAs detected in bone tissue samples, 346 (54%) were present in osteoblasts and/or osteoclasts. The other 46% were not identified in any of the bone cells analyzed. Intersection of osteoblast and osteoclast arrays identified 101 miRNAs shared by both cell types, which accounts for 30-40% of miRNAs detected in these cells. In osteoblasts, 266 miRNAs were detected, of which 243 (91%) were also present in the total bone array, representing 38% of all bone miRNAs. In osteoclasts, 340 miRNAs were detected, of which 196 (58%) were also present in the bone tissue array, representing 31% of all miRNAs detected in total bone. These analyses provide an overview of miRNAs expressed in bone tissue, broadening our knowledge in the microRNA field.