MicroRNA-206 regulates the secretion of inflammatory cytokines and MMP9 expression by targeting TIMP3 in Mycobacterium tuberculosis–infected THP-1 human macrophages

YY1 Contributes to the Inflammatory Responses of Mycobacterium tuberculosis-Infected Macrophages Through Transcription Activation-Mediated Upregulation TLR4

Tuberculosis (TB) is a chronic respiratory infectious disease and is induced by Mycobacterium tuberculosis (M.tb) infection. Macrophages serve as the cellular home in immunoreaction against M.tb infection, which is tightly regulated through Toll-like receptor 4 (TLR4) expression. Therefore, this study is designed to explore the role and mechanism of TLR4 in mycobacterial injury in human macrophages (THP-1 cells) after M.tb infection. Cell proliferation and apoptosis were assessed using MTT, EdU, and flow cytometry assays. ELISA kits were utilized to assess the levels of Interleukin-6 (IL-6), IL-1β, and tumor necrosis factor α (TNF-α). The binding between Yin-Yang-1 (YY1) and TLR4 promoter was predicted by JASPAR and verified using Chromatin immunoprecipitation (ChIP) and dual-luciferase reporter assays. M.tb infection might repress THP-1 cell proliferation, and induce cell apoptosis and inflammatory response in a multiplicity of infection (MOI)-dependent manner. Moreover, M.tb infection increased the expression of TLR4 in HTP-1 cells in an MOI-dependent way, and its downregulation might overturn M.tb infection-mediated HTP-1 cell damage and inflammatory response. At the molecular level, YY1 was a transcription factor of TLR4 and promoted TLR4 transcription via binding to its promoter region. Besides, YY1 might activate the NF-kB signaling pathway via regulating TLR4. Meanwhile, TLR4 inhibitor BAY11-7082 might overturn the repression effect of TLR4 on M.tb-infected HTP-1 cell damage. YY1-activated TLR4 might aggravate mycobacterial injury in human macrophages after M.tb infection by the NF-kB pathway, providing a promising therapeutic target for TB treatment.

Xuebijing improves inflammation and pyroptosis of acute lung injury by up-regulating miR-181d-5p-mediated SPP1 inactivation

BACKGROUND

Xuebijing (XBJ) is widely applied in the treatment of Acute Lung Injury (ALI). This study focused on the potential mechanism of XBJ in Lipopolysaccharide (LPS)-induced ALI.

METHODS

The rat ALI model was established by injection of LPS (10 mg/kg) and pretreated with XBJ (4 mL/kg) three days before LPS injection. BEAS-2B cell line was stimulated with LPS (1 μg/mL) and ATP (5 mM) to induce pyroptosis, and XBJ (2 g/L) was pretreated 24h before induction. The improvement effects of XBJ on pulmonary edema, morphological changes, and apoptosis in ALI lung tissue were evaluated by lung wet/dry weight ratio, HE-staining, and TUNEL staining. Inflammatory cytokines in lung tissue and cell supernatant were determined by ELISA. pyroptosis was detected by flow cytometry. Meanwhile, the expressions of miR-181d-5p, SPP1, p-p65, NLRP3, ASC, caspase-1, p20, and GSDMD-N in tissues and cells were assessed by RT-qPCR and immunoblotting. The relationship between miR-181d-5p and SPP1 in experimental inflammation was reported by dual luciferase assay.

RESULTS

XBJ could improve inflammation and pyroptosis of ALI by inhibiting contents of inflammatory cytokines, and levels of inflammation- and pyroptosis-related proteins. Mechanistically, XBJ could up-regulate miR-181d-5p and inhibit SPP1 in ALI. miR-181d-5p can target the regulation of SPP1. Depressing miR-181d-5p compensated for the ameliorative effect of XBJ on ALI, and overexpressing SPP1 suppressed the attenuating effect of XBJ on LPS-induced inflammation and pyroptosis.

CONCLUSION

XBJ can regulate the miR-181d-5p/SPP1 axis to improve inflammatory response and pyroptosis in ALI.

Effect of Borrelia burgdorferi on the Expression of miRNAs in Breast Cancer and Normal Mammary Epithelial Cells

Breast cancer is one of the leading causes of death in women worldwide. Recent studies have demonstrated that inflammation due to infections with microorganisms could play a role in breast cancer development. One of the known human pathogens, Borrelia burgdorferi, the causative agent of Lyme disease, has been shown to be present in various types of breast cancer and is associated with poor prognosis. We reported that B. burgdorferi can invade breast cancer cells and affect their tumorigenic phenotype. To better understand the genome-wide genetic changes caused by B. burgdorferi, we evaluated the microRNA (miRNA or miR) expression profiles of two triple-negative breast cancer cell lines and one non-tumorigenic mammary cell line before and after B. burgdorferi infection. Using a cancer-specific miRNA panel, four miRNAs (miR-206, 214-3p, 16-5p, and 20b-5p) were identified as potential markers for Borrelia-induced changes, and the results were confirmed by quantitative real-time reverse transcription (qRT-PCR). Among those miRNAs, miR-206 and 214 were the most significantly upregulated miRNAs. The cellular impact of miR-206 and 214 was evaluated using DIANA software to identify related molecular pathways and genes. Analyses showed that the cell cycle, checkpoints, DNA damage-repair, proto-oncogenes, and cancer-related signaling pathways are mostly affected by B. burgdorferi infection. Based on this information, we have identified potential miRNAs which could be further evaluated as biomarkers for tumorigenesis caused by pathogens in breast cancer cells.

Bacteria and macrophages in the tumor microenvironment

Cancer and microbial infections are significant worldwide health challenges. Numerous studies have demonstrated that bacteria may contribute to the emergence of cancer. In this review, we assemble bacterial species discovered in various cancers to describe their variety and specificity. The relationship between bacteria and macrophages in cancer is also highlighted, and we look for ample proof to establish a biological basis for bacterial-induced macrophage polarization. Finally, we quickly go over the potential roles of metabolites, cytokines, and microRNAs in the regulation of the tumor microenvironment by bacterially activated macrophages. The complexity of bacteria and macrophages in cancer will be revealed as we gain a better understanding of their pathogenic mechanisms, which will lead to new therapeutic approaches for both inflammatory illnesses and cancer.

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

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

microRNAs associated with the pathogenesis and their role in regulating various signaling pathways during Mycobacterium tuberculosis infection

Despite more than a decade of active study, tuberculosis (TB) remains a serious health concern across the world, and it is still the biggest cause of mortality in the human population. Pathogenic bacteria recognize host-induced responses and adapt to those hostile circumstances. This high level of adaptability necessitates a strong regulation of bacterial metabolic characteristics. Furthermore, the immune reponse of the host virulence factors such as host invasion, colonization, and survival must be properly coordinated by the pathogen. This can only be accomplished by close synchronization of gene expression. Understanding the molecular characteristics of mycobacterial pathogenesis in order to discover therapies that prevent or resolve illness relies on the bacterial capacity to adjust its metabolism and replication in response to various environmental cues as necessary. An extensive literature details the transcriptional alterations of host in response to in vitro environmental stressors, macrophage infection, and human illness. Various studies have recently revealed the finding of several microRNAs (miRNAs) that are believed to play an important role in the regulatory networks responsible for adaptability and virulence in Mycobacterium tuberculosis. We highlighted the growing data on the existence and quantity of several forms of miRNAs in the pathogenesis of M. tuberculosis, considered their possible relevance to disease etiology, and discussed how the miRNA-based signaling pathways regulate bacterial virulence factors.

MicroRNAs as immune regulators and biomarkers in tuberculosis

Tuberculosis (TB), which is caused by Mycobacterium tuberculosis (Mtb), is one of the most lethal infectious disease worldwide, and it greatly affects human health. Some diagnostic and therapeutic methods are available to effectively prevent and treat TB; however, only a few systematic studies have described the roles of microRNAs (miRNAs) in TB. Combining multiple clinical datasets and previous studies on Mtb and miRNAs, we state that pathogens can exploit interactions between miRNAs and other biomolecules to avoid host mechanisms of immune-mediated clearance and survive in host cells for a long time. During the interaction between Mtb and host cells, miRNA expression levels are altered, resulting in the changes in the miRNA-mediated regulation of host cell metabolism, inflammatory responses, apoptosis, and autophagy. In addition, differential miRNA expression can be used to distinguish healthy individuals, patients with TB, and patients with latent TB. This review summarizes the roles of miRNAs in immune regulation and their application as biomarkers in TB. These findings could provide new opportunities for the diagnosis and treatment of TB.

Immune regulation and emerging roles of noncoding RNAs in Mycobacterium tuberculosis infection

Tuberculosis, caused by Mycobacterium tuberculosis, engenders an onerous burden on public hygiene. Congenital and adaptive immunity in the human body act as robust defenses against the pathogens. However, in coevolution with humans, this microbe has gained multiple lines of mechanisms to circumvent the immune response to sustain its intracellular persistence and long-term survival inside a host. Moreover, emerging evidence has revealed that this stealthy bacterium can alter the expression of demic noncoding RNAs (ncRNAs), leading to dysregulated biological processes subsequently, which may be the rationale behind the pathogenesis of tuberculosis. Meanwhile, the differential accumulation in clinical samples endows them with the capacity to be indicators in the time of tuberculosis suffering. In this article, we reviewed the nearest insights into the impact of ncRNAs during Mycobacterium tuberculosis infection as realized via immune response modulation and their potential as biomarkers for the diagnosis, drug resistance identification, treatment evaluation, and adverse drug reaction prediction of tuberculosis, aiming to inspire novel and precise therapy development to combat this pathogen in the future.

Neuropilin-1 in the pathogenesis of preeclampsia, HIV-1, and SARS-CoV-2 infection: A review

This review explores the role of transmembrane neuropilin-1 (NRP-1) in pregnancy, preeclampsia (PE), human immunodeficiency virus type 1 (HIV-1) and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections. Since these conditions are assessed independently, this review attempts to predict their comorbid clinical manifestations. Dysregulation of NRP-1 contributes to the pathogenesis of PE by (a) impairing vascular endothelial growth factor (VEGF) signaling for adequate spiral artery remodeling and placentation, (b) inducing syncytiotrophoblast (ST) cell apoptosis and increasing ST-derived microparticle circulation and (c) by decreasing regulatory T cell activity predisposing maternal immune intolerance. Although NRP-1 is upregulated in SARS-CoV-2 placentae, its exploitation for SARS-CoV-2 internalization and increased infectivity may alter angiogenesis through the competitive inhibition of VEGF. The anti-inflammatory nature of NRP-1 may aid its upregulation in HIV-1 infection; however, the HIV-accessory protein, tat, reduces NRP-1 expression. Upregulated NRP-1 in macrophages and dendritic cells also demonstrated HIV-1 resistance/reduced infectivity. Notably, HIV-1-infected pregnant women receiving antiretroviral therapy (ART) to prevent vertical transmission may experience immune reconstitution, impaired decidualization, and elevated markers of endothelial injury. Since endothelial dysfunction and altered immune responses are central to PE, HIV-1 infection, ART usage and SARS-CoV-2 infection, it is plausible that an exacerbation of both features may prevail in the synergy of these events. Additionally, this review identifies microRNAs (miRNAs) mediating NRP-1 expression. MiR-320 and miR-141 are overexpressed in PE, while miR-206 and miR-124-3p showed increased expression in PE and HIV-1 infection. Additionally, miR-214 is overexpressed in PE, HIV-1 and SARS-CoV-2 infection, implicating treatment strategies to reduce these miRNAs to upregulate and normalize NRP-1 expression. However, inconsistencies in the data of the role and regulation of miRNAs in PE, HIV-1 and SARS-CoV-2 infections require clarification. This review provides a platform for early diagnosis and potential therapeutic intervention of PE, HIV-1, and SARS-CoV-2 infections independently and as comorbidities.

Expression Analysis of Moritella viscosa-Challenged Atlantic Salmon Identifies Disease-Responding Genes, MicroRNAs and Their Predicted Target Genes and Pathways

Moritella viscosa is a bacterial pathogen causing winter-ulcer disease in Atlantic salmon. The lesions on affected fish lead to increased mortality, decreased fish welfare, and inferior meat quality in farmed salmon. MicroRNAs (miRNAs) are small non-coding RNAs involved in post-transcriptional regulation by guiding the miRNA-induced silencing complex to specific mRNA transcripts (target genes). The goal of this study was to identify miRNAs responding to Moritella viscosa in salmon by investigating miRNA expression in the head-kidney and the muscle/skin from lesion sites caused by the pathogen. Protein coding gene expression was investigated by microarray analysis in the same materials. Seventeen differentially expressed guide-miRNAs (gDE-miRNAs) were identified in the head-kidney, and thirty-nine in lesion sites, while the microarray analysis reproduced the differential expression signature of several thousand genes known as infection-responsive. In silico target prediction and enrichment analysis suggested that the gDE-miRNAs were predicted to target genes involved in immune responses, hemostasis, angiogenesis, stress responses, metabolism, cell growth, and apoptosis. The majority of the conserved gDE-miRNAs (e.g., miR-125, miR-132, miR-146, miR-152, miR-155, miR-223 and miR-2188) are known as infection-responsive in other vertebrates. Collectively, the findings indicate that gDE-miRNAs are important post-transcriptional gene regulators of the host response to bacterial infection.

lncRNA SNHG12 Inhibition Based on Microsystem Cell Imaging Technology Protects the Endothelium from LPS-Induced Inflammation by Inhibiting the Expression of miR-140-3p Target Gene fndc5

Acute lung injury (ALI) is a serious disease with a high incidence rate, characterized by uncontrolled inflammation and apoptosis. At present, long-chain noncoding RNA (lncRNA) is a noncoding RNA with a length of more than 200 nucleotides. It plays an important role in ALI, cell cycle regulation, cell differentiation regulation, and many other life activities. Therefore, the current focus is to identify and evaluate the possible functions and potential molecular mechanisms of lncRNA small nuclear host gene 12 (SNHG12). Lipopolysaccharide (LPS)-induced mice model and in vitro cell model were established. Gene knockout is to use the principle of DNA homologous recombination to replace the target gene fragment with the designed homologous fragment, so as to achieve the purpose of gene knockout. The relationship between lncRNA SNHG12 expression and ALI was studied through knockdown and overexpression experiments. The qRT-PCR, ROS, immunohistochemistry, histopathology, TUNEL, and cell permeability tests were performed to further verify the possible targets and mechanisms of action. The expression of lncRNA SNHG12 in lung tissue was lower than that in normal tissue. The results showed that lncRNA SNHG12 could reduce lung cell injury and inflammatory cytokines induced by ALI. Bioinformatics analysis showed that lncRNA SNHG12 interacted with miR-140-3p. Subsequent experiments confirmed the link between lncRNA SNHG12, miR-140-3p, and fndc5. Furthermore, this study indicates that lncRNA SNHG12 has a key function in ALI. The results of this study demonstrated the role of lncRNA SNHG12 in the pathological process of ALI and provided a reference for developing novel anti-ALI treatments so that patients can get timely treatment, avoid causing multiple organ failure, and will not endanger their life safety.

Immunologic and imaging signatures in post tuberculosis lung disease

Post Tuberculosis Lung Disease (PTLD) affects millions of tuberculosis survivors and is a global health burden. The immune mechanisms that drive PTLD are complex and have historically been under investigated. Here, we discuss two immune-mediated paradigms that could drive human PTLD. We review the characteristics of a fibrotic granuloma that favors the development of PTLD via an abundance of T-helper-2 and T-regulatory cells and an upregulation of TGF-β mediated collagen deposition. Next, we discuss the post-primary tuberculosis paradigm and the complex mixture of caseous pneumonia, cavity formation and fibrosis that can also lead to PTLD. We review the delicate balance between cellular subsets and cytokines of the innate and adaptive immune system in conjunction with host-derived proteases that can perpetuate the parenchymal lung damage seen in PTLD. Next, we discuss the role of novel host directed therapies (HDT) to limit the development of PTLD and in particular, the recent repurposing of established medications such as statins, metformin and doxycycline. Finally, we review the emerging role of novel imaging techniques as a non-invasive modality for the early recognition of PTLD. While access to computed tomography imaging is unlikely to be available widely in countries with a high TB burden, its use in research settings can help phenotype PTLD. Due to a lack of disease-specific biomarkers and controlled clinical trials, there are currently no evidence-based recommendations for the management of PTLD. It is likely that an integrated antifibrotic strategy that could simultaneously target inflammatory and pro-fibrotic pathways will probably emerge as a successful way to treat this complex condition. In a disease spectrum as wide as PTLD, a single immunologic or radiographic marker may not be sufficient and a combination is more likely to be a successful surrogate that could aid in the development of successful HDTs.

CHOP Increases TRIB3-Dependent miR-208 Expression to Potentiate Vascular Smooth Muscle Cell Proliferation and Migration by Downregulating TIMP3 in Atherosclerosis

BACKGROUND

C/EBP homologous protein (CHOP) has been identified as a suitable therapeutic target to combat atherosclerosis but the mechanism has not been fully studied. Here, we sought to define the role and underlying mechanism of CHOP in atherosclerosis.

METHODS

Mouse models of atherosclerosis in ApoE-/- mice were established by high-fat feeding, where miR-208 expression was determined. Then atherosclerotic plaque tissues were isolated from the model mice. Loss- and gain-function assays were performed on trypsinized vascular smooth muscle cells (VSMCs) to test the in vitro effect of CHOP in controlling the tribbles homologue 3 (TRIB3)/microRNA-208 (miR-208)/tissue inhibitor of metalloproteinases-3 (TIMP3) axis in atherosclerosis by determining cell proliferation and migration as well as blood lipid levels. Moreover, expression of α-smooth muscle actin (α-SMA) and type I collagen expression was determined using immunofluorescence staining to assess plaque stability in mice.

RESULTS

miR-208 expression was elevated in atherosclerosis samples and miR-208 overexpression promoted proliferation and migration of VSMCs but diminished plaque stability in mice. TIMP3 was targeted by miR-208, which could be abrogated by upregulation of TIMP3. In addition, CHOP increased TRIB3 expression to upregulate miR-208 and to downregulate TIMP3, which potentiated VSMC proliferation and migration in vitro and in vivo.

CONCLUSION

Taken together, inhibition of CHOP may inhibit the proliferation and migration of VSMCs as well as reduce the levels of TC, TG, and LDL-C but increase the level of HDL-C through the TRIB3/miR-208/TIMP3 axis, thereby inhibiting the progression of atherosclerosis.

Serum microRNA miR-491-5p/miR-206 Is Correlated with Poor Outcomes/Spontaneous Hemorrhagic Transformation after Ischemic Stroke: A Case Control Study

Background: It is unclear whether miR-491-5p, miR-206, miR-21-5p or miR-3123 are associated with functional outcomes and hemorrhagic transformation (HT) after acute ischemic stroke (AIS). In this study, we aimed to investigate the correlation between these four microRNAs and functional outcomes, as well as spontaneous HT after AIS; Methods: We included 215 AIS patients and retrospectively assayed for miR-21-5p, miR-206, miR-3123 and miR-491-5p levels in serum. Poor functional outcome was defined as a modified Rankin Scale score ≥ 3. Spontaneous HT referred to hemorrhage detected in follow-up brain imaging but not on admission, without reperfusion therapies. Logistic regression, generalized additive model and 2-piecewise regression model were used to explore the independent, non-linear correlation between miRNA expression levels and outcomes; Results: We included 215 AIS patients. Higher miR-491-5p level independently reduced the risk of poor functional outcomes at 1 year (OR 0.90, 95% CI 0.82–0.98, corrected p value = 0.044). Higher miR-206 level significantly increased the risk of spontaneous HT (OR 1.64, 95% CI 1.17–2.30, corrected p value = 0.016). There was a nonlinear correlation found between miR-491-5p level and 1 year outcome with an inflection point of 2.180, while an approximately linear correlation was observed with an inflection point of 2.037 between miR-206 level and spontaneous HT; Conclusions: Higher serum miR-491-5p level independently reduced risk of 1-year poor functional outcome of AIS patients. Higher serum miR-206 level independently increased the risk of spontaneous HT in AIS patients. These two miRNAs may be as the potential biomarkers for improving prognosis after AIS.

miR-495 Regulates Cellular Reactive Oxygen Species Levels by Targeting sod2 To Inhibit Intracellular Survival of Mycobacterium tuberculosis in Macrophages

Mycobacterium tuberculosis is a chronic infectious disease pathogen. To date, tuberculosis is a major infectious disease that endangers human health. To better prevent and treat tuberculosis, it is important to study the pathogenesis of M. tuberculosis. Based on early-stage laboratory research results, in this study, we verified the upregulation of sod2 in Bacillus Calmette-Guérin (BCG) and H37Rv infection. By detecting BCG/H37Rv intracellular survival in sod2-silenced and sod2-overexpressing macrophages, sod2 was found to promote the intracellular survival of BCG/H37Rv. miR-495 then was determined to be downregulated by BCG/H37Rv. BCG/H37Rv can upregulate sod2 expression by miR-495 to promote the intracellular survival of BCG/H37Rv through a decline in ROS levels. This study provides a theoretical basis for developing new drug targets and treating tuberculosis.

Serum small extracellular vesicles promote M1 activation of microglia after cerebral ischemia/reperfusion injury

Microglial M1 activation is detrimental to stroke outcomes. Recent studies have shown that circulating small extracellular vesicles (sEVs) can deliver miRNAs to target cells and regulate recipient cell functions. Herein, we tested the hypothesis that miRNA delivery by serum sEVs after cerebral ischemia/reperfusion (I/R) injury promote microglial M1 activation, demonstrating that serum sEVs from middle cerebral artery occlusion (MCAO) mice promoted proliferation and M1 activation of BV2 microglia. To explore the underlying mechanism of serum sEVs-mediated microglial activation in the early phase of cerebral I/R injury, we examined the effects of ischemic brain injury on the serum sEVs miRNAs profile in a mouse MCAO model using small RNAseq. Of the 1257 detected miRNA replications, the levels of 72 were significantly modulated. Bioinformatics analysis revealed that a panel of miRNAs was closely associated with inflammation, and in vitro experiments demonstrated that serum sEVs from MCAO mice could effectively transfer inflammatory miRNAs to BV2 microglia. Collectively, our data suggested that miRNAs delivered by serum sEVs after cerebral I/R injury promoted microglial M1 activation. The identification of microglial activation regulators in future studies will give rise to more effective treatments for stroke.

Both Full-Length and Protease-Cleaved Products of Osteopontin Are Elevated in Infectious Diseases

Circulating full-length osteopontin (FL-OPN) is elevated in plasma from patients with various infectious diseases, such as adult T-cell leukemia, Mycobacterium tuberculosis (TB), hepatitis virus infection, leptospirosis, acquired immune deficiency syndrome (AIDS), AIDS/TB, and coronavirus disease 2019 (COVID-19). Proteolysis of OPN by thrombin, matrix metalloproteases, caspase 8/3, cathepsin D, plasmin, and enterokinase generates various cleaved OPNs with a variety of bioactivities by binding to different target cells. Moreover, OPN is susceptible to gradual proteolysis. During inflammation, one of the cleaved fragments, N-terminal thrombin-cleaved OPN (trOPN or OPN-Arg¹⁶⁸ [OPN-R]), induces dendritic cell (DC) adhesion. Further cleavage by carboxypeptidase B2 or carboxypeptidase N removes Arg¹⁶⁸ from OPN-R to OPN-Leu¹⁶⁷ (OPN-L). Consequently, OPN-L decreases DC adhesion. In particular, the differences in plasma level over time are observed between FL-OPN and its cleaved OPNs during inflammation. We found that the undefined OPN levels (mixture of FL-OPN and cleaved OPN) were elevated in plasma and reflected the pathology of TB and COVID-19 rather than FL-OPN. These infections are associated with elevated levels of various proteases. Inhibition of the cleavage or the activities of cleaved products may improve the outcome of the therapy. Research on the metabolism of OPN is expected to create new therapies against infectious diseases.

The Role of microRNAs and Long Non-Coding RNAs in the Regulation of the Immune Response to Mycobacterium tuberculosis Infection

Non-coding RNAs have emerged as critical regulators of the immune response to infection. MicroRNAs (miRNAs) are small non-coding RNAs which regulate host defense mechanisms against viruses, bacteria and fungi. They are involved in the delicate interplay between Mycobacterium tuberculosis, the causative agent of tuberculosis (TB), and its host, which dictates the course of infection. Differential expression of miRNAs upon infection with M. tuberculosis, regulates host signaling pathways linked to inflammation, autophagy, apoptosis and polarization of macrophages. Experimental evidence suggests that virulent M. tuberculosis often utilize host miRNAs to promote pathogenicity by restricting host-mediated antibacterial signaling pathways. At the same time, host- induced miRNAs augment antibacterial processes such as autophagy, to limit bacterial proliferation. Targeting miRNAs is an emerging option for host-directed therapies. Recent studies have explored the role of long non-coding RNA (lncRNAs) in the regulation of the host response to mycobacterial infection. Among other functions, lncRNAs interact with chromatin remodelers to regulate gene expression and also function as miRNA sponges. In this review we attempt to summarize recent literature on how miRNAs and lncRNAs are differentially expressed during the course of M. tuberculosis infection, and how they influence the outcome of infection. We also discuss the potential use of non-coding RNAs as biomarkers of active and latent tuberculosis. Comprehensive understanding of the role of these non-coding RNAs is the first step towards developing RNA-based therapeutics and diagnostic tools for the treatment of TB.

Mycobacterial infection-induced miR-206 inhibits protective neutrophil recruitment via the CXCL12/CXCR4 signalling axis

Pathogenic mycobacteria actively dysregulate protective host immune signalling pathways during infection to drive the formation of permissive granuloma microenvironments. Dynamic regulation of host microRNA (miRNA) expression is a conserved feature of mycobacterial infections across host-pathogen pairings. Here we examine the role of miR-206 in the zebrafish model of Mycobacterium marinum infection, which allows investigation of the early stages of granuloma formation. We find miR-206 is upregulated following infection by pathogenic M. marinum and that antagomir-mediated knockdown of miR-206 is protective against infection. We observed striking upregulation of cxcl12a and cxcr4b in infected miR-206 knockdown zebrafish embryos and live imaging revealed enhanced recruitment of neutrophils to sites of infection. We used CRISPR/Cas9-mediated knockdown of cxcl12a and cxcr4b expression and AMD3100 inhibition of Cxcr4 to show that the enhanced neutrophil response and reduced bacterial burden caused by miR-206 knockdown was dependent on the Cxcl12/Cxcr4 signalling axis. Together, our data illustrate a pathway through which pathogenic mycobacteria induce host miR-206 expression to suppress Cxcl12/Cxcr4 signalling and prevent protective neutrophil recruitment to granulomas.

Ursolic acid ameliorates Nthy-ori 3-1 cells injury induced by IL-1β through limiting MALAT1/miR-206/PTGS1 ceRNA network and NF-κB signaling pathway

RATIONALE

Ursolic acid (UA) has exhibited anti-inflammatory and anti-oxidative drug effects.

OBJECTIVES

In the research, we assessed the effects of UA on Nthy-ori 3-1 cells stimulated by IL-1β and attempted to elucidate the mechanisms underlying the effects.

METHODS

Autoimmune thyroiditis (AIT) was simulated using Nthy-ori 3-1 cells by IL-1β (10 μM) treatment. UA (20 μM) was applied to ameliorate the injury of Nthy-ori 3-1 cells. The target of UA was predicted by TCMSP, BATMAN, and GEO database. Targeted relationship between lncRNA MALAT1 and miR-206, as well as miR-206 and PTGS1, was predicted by bioinformatics software and identified by dual luciferase assays. Cytokines in the cell supernatant and the apoptosis of cells were detected by ELISAs and flow cytometry assays, respectively. Expression levels of NF-κB signaling pathway-related proteins were estimated by western blot.

RESULTS

By enquiring TCMSP, BATMAN, and GEO database, PTGS1 was identified as a target of UA. Afterward, a ceRNA network among MALAT1, miR-206, and PTGS1 was constructed. The expression levels of MALAT1 and PTGS1 in AIT tissues were obviously enhanced. Moreover, the ceRNA network formed by MALAT1/miR-206/PTGS1 contributed to the damage of Nthy-ori 3-1 cells induced by IL-1β. However, UA ameliorated the Nthy-ori 3-1 cells injury induced by IL-1β through mediating the MALAT1/miR-206/PTGS1 ceRNA network and NF-κB signaling pathway.

CONCLUSIONS

UA treatment significantly relieved the injury of Nthy-ori 3-1 cells via inhibiting the ceRNA mechanism of MALAT1/miR-206/PTGS1 and inflammatory pathways, insinuating that UA may be helpful for the treatment of AIT.

Interplay between miRNAs and Mycobacterium tuberculosis: diagnostic and therapeutic implications

Increasing evidence suggests that mycobacteria change the host miRNA profile to their advantage. The active participation of miRNAs in controlling immune responses in TB has raised the possibility of utilizing miRNA-based therapy itself or canonically with a standard drug regimen for shortening the duration of treatment. The development of delivery systems for optimal delivery of oligonucleotides, including small interfering (si)RNA/miRNAs-based therapeutics has shown potential as a new therapeutic intervention. However, studies related to the exploitation of miRNAs as both biomarkers and as therapeutics in TB are scarce; thus, more in vitro and in vivo studies are required to fully determine the role of miRNAs as potential diagnostic biomarkers and to improve the pharmacological profile of this class of therapeutics.

Differential expression of miRNAs in canine peripheral blood mononuclear cells (PBMC) exposed to Leishmania infantum in vitro

Visceral Leishmaniasis (VL) is a neglected tropical disease, caused by L. infantum in the New World, where dogs are the main reservoir. These parasites can regulate host immune response through miRNA differential expression in the early stages of infection; however such early response has not yet been investigated in the canine model. PBMC from healthy dogs were exposed to L. infantum in vitro and microarray analysis showed an upregulation of miR-206, miR-302d, miR-433, miR-214, miR-493, miR-514, miR-1835, miR-210, miR-539, miR-432, miR-188, miR-345 and downregulation of miR-489 and miR-503 in comparison to non-exposed control cells, at 24 h post-exposure. In silico target prediction showed that the upregulated miRNAs target 1541 genes, which can modulate important pathways involved in the early immune responses, like the "MAPK signaling pathway", one of the most relevant pathways to Leishmania survival inside host cells. These findings shed light on parasite modulation of host immunity following Leishmania infection, which in turn can be explored for drug development.

MicroRNA research: The new dawn of Tuberculosis

Tuberculosis (TB) is global, one of the most fatal communicable diseases and leading cause of worldwide mortality. One-third of the global population is latently affected by Mtb (Mycobacterium tuberculosis) due to its ability to circumvent the host's immune response for its own survival. MicroRNAs (miRNAs) are small, non-coding RNAs which function at the post-transcriptional level and are critical in fine-tuning immune responses regulating the repertoire of genes expressed in immune cells. Recent studies have established their crucial role against TB. Furthermore, the differential expression pattern of miRNAs has revealed the potential role of miRNAs as biomarkers which could be utilized to differentiate between healthy controls and active TB patients or between active and latent TB. The recent advancements made in the field of miRNA regulation of the host responses against TB, as well as the potential of miRNAs as biomarkers for TB diagnosis are discussed here in this review.

The role of non-coding RNA on macrophage modification in tuberculosis infection

Tuberculosis (TB), a serious disease caused by Mycobacterium tuberculosis (Mtb), remains the world's top infectious killer. It is well-established that TB can circumvent the host's immune response for long-term survival. Macrophages serve as the major host cells for TB growth and persistence and their altered functions are critical for the response of the host defense against TB exposure (elimination, latency, reactivation, and bacillary dissemination). Noncoding RNAs are crucial posttranscriptional regulators of macrophage discrimination. Therefore, this review highlights the regulatory mechanism underlying the relationship between noncoding RNAs and macrophages in TB infection, which may facilitate the identification of potential therapeutic targets and effective diagnosis biomarkers for TB disease.

MicroRNA-206 antagomiR‒enriched extracellular vesicles attenuate lung ischemia‒reperfusion injury through CXCL1 regulation in alveolar epithelial cells

BACKGROUND

Our hypothesis is that the immunomodulatory capacities of mesenchymal stem cell‒derived extracellular vesicles (EVs) can be enhanced by specific microRNAs (miRNAs) to effectively attenuate post-transplant lung ischemia‒reperfusion (IR) injury.

METHODS

The expression of miR-206 was analyzed in bronchoalveolar lavage (BAL) fluid of patients on Days 0 and 1 after lung transplantation. Lung IR injury was evaluated in C57BL/6 mice using a left lung hilar-ligation model with or without treatment with EVs or antagomiR-206‒enriched EVs. Murine lung tissue was used for miRNA microarray hybridization analysis, and cytokine expression, lung injury, and edema were evaluated. A donation after circulatory death and murine orthotopic lung transplantation model was used to evaluate the protection by enriched EVs against lung IR injury. In vitro studies analyzed type II epithelial cell activation after coculturing with EVs.

RESULTS

A significant upregulation of miR-206 was observed in the BAL fluid of patients on Day 1 after lung transplantation compared with Day 0 and in murine lungs after IR injury compared with sham. Treatment with antagomiR-206‒enriched EVs attenuated lung dysfunction, injury, and edema compared with treatment with EVs alone after murine lung IR injury. Enriched EVs reduced lung injury and neutrophil infiltration as well as improved allograft oxygenation after murine orthotopic lung transplantation. Enriched EVs significantly decreased proinflammatory cytokines, especially epithelial cell‒dependent CXCL1 expression, in the in vivo and in vitro IR injury models.

CONCLUSIONS

EVs can be used as biomimetic nanovehicles for protective immunomodulation by enriching them with antagomiR-206 to mitigate epithelial cell activation and neutrophil infiltration in the lungs after IR injury.

Biology of Tissue Inhibitor of Metalloproteinase 3 (TIMP3), and Its Therapeutic Implications in Cardiovascular Pathology

Tissue inhibitor of metalloproteinase 3 (TIMP3) is unique among the four TIMPs due to its extracellular matrix (ECM)-binding property and broad range of inhibitory substrates that includes matrix metalloproteinases (MMPs), a disintegrin and metalloproteinases (ADAMs), and ADAM with thrombospondin motifs (ADAMTSs). In addition to its metalloproteinase-inhibitory function, TIMP3 can interact with proteins in the extracellular space resulting in its multifarious functions. TIMP3 mRNA has a long 3' untranslated region (UTR) which is a target for numerous microRNAs. TIMP3 levels are reduced in various cardiovascular diseases, and studies have shown that TIMP3 replenishment ameliorates the disease, suggesting a therapeutic potential for TIMP3 in cardiovascular diseases. While significant efforts have been made in identifying the effector targets of TIMP3, the regulatory mechanism for the expression of this multi-functional TIMP has been less explored. Here, we provide an overview of TIMP3 gene structure, transcriptional and post-transcriptional regulators (transcription factors and microRNAs), protein structure and partners, its role in cardiovascular pathology and its application as therapy, while also drawing reference from TIMP3 function in other diseases.

MMP-9-Related microRNAs as Prognostic Markers for Hemorrhagic Transformation in Cardioembolic Stroke Patients

Studies suggest that microRNAs that regulate expression of matrix metalloproteinase (MMP)-9 may be involved in hemorrhagic transformation (HT) after cardioembolic stroke, so we examined whether such microRNAs could predict HT in acute cardioembolic stroke patients. Blood samples were prospectively collected from patients who later experienced HT (n = 29) or did not (n = 29), and the samples were assayed for eight microRNAs identified as related to MMP-9 based on three microRNA databases. Expression levels of these microRNAs were analyzed by quantitative real-time polymerase chain reaction (qRT-PCR) in 28 of the 58 patients, 14 of whom suffered HT and 14 of whom did not. Four differentially expressed miRNAs were identified: hsa-miR-21-5p, hsa-miR-206, hsa-miR-491-5p, and hsa-miR-3123. Subsequent qRT-PCR analysis of these four miRNAs across all 58 patients showed that levels of miR-21-5p, miR-206, and miR-3123 were significantly higher in patients with HT than in those without HT, while expression of miR-491-5p was similar between the two groups. The area under the receiver operating characteristic curve for predicting HT was 0.677 (95% CI 0.535–0.818) for miR-21-5p, 0.687 (95% CI 0.543–0.830) for miR-206, and 0.661 (95% CI 0.512–0.810) for miR-3123. Our results suggest that these three microRNAs may be prognostic markers for HT after cardioembolic stroke, which should be verified by future studies with large samples.

Downregulation of microRNA-204 increases the expression of matrix metallopeptidase 9 in pediatric patients with pulpitis and Helicobacter pylori infection in the stomach

The present study examined the expression of microRNA (miRNA or miR)-204 in pulp tissues, blood and saliva from pediatric patients with pulpitis and an underlying Helicobacter pylori (Hp) infection in the stomach, and the mechanism of the associated regulation by miR-204 was assessed. A total of 26 children with pulpitis who received tooth extraction at the Children's Hospital of Nanjing Medical University (Nanjing, China) between December 2014 and August 2016 were diagnosed with Hp infection in the stomach and included in the present study (HP⁺ group); furthermore, 19 children with pulpitis but without Hp infection in the stomach were enrolled as a control (HP^- group). Pulp tissues, blood (serum) and saliva samples were collected from all subjects. Reverse-transcription quantitative polymerase chain reaction was used to determine the expression of miR-204 and matrix metalloproteinase 9 (MMP9) mRNA. Western blot analysis was performed to determine MMP9 protein expression in pulp tissues, while ELISA was performed to measure the contents of MMP9 in serum and saliva. A dual luciferase reporter assay was used to identify the direct interaction between miR-204 and its target protein. The results indicated that Hp infection in the stomach was associated with an upregulation of MMP9 mRNA and protein in pulp tissues, serum and saliva from children with pulpitis. Furthermore, the levels of miR-204 in pulp tissues, serum and saliva from children with pulpitis and Hp infection in the stomach were significantly reduced. miR-204 was confirmed to regulate the expression of MMP9 by directly binding with the 3'-untranslated region of MMP9 mRNA. The present study demonstrated that MMP9 expression in pulp tissues, blood and saliva from children with pulpitis and Hp infection in the stomach was upregulated, while miR-204 expression was downregulated. miR-204 may affect inflammatory processes and other oral diseases in children with pulpitis and Hp infection via MMP9, and may be a potential marker for the detection of Hp infection in children with pulpitis.

miR-222-3p promotes osteosarcoma cell migration and invasion through targeting TIMP3

BACKGROUND

Abnormal expression of miRNAs has been reported in osteosarcoma (OS), and miR-222-3p levels have been found to be increased in the serum of OS patients. However, the exact role of miR-222-3p in OS remains unclear. In the present study, we aimed to identify the molecular mechanism underlying the role of miR-222-3p in the development of OS.

METHODS

We examined the expression level of miR-222-3p in OS tissues and OS cells using reverse-transcription quantitative PCR (RT-qPCR) analysis. MTT, colony formation, and transwell invasion assays were used to analyze the effects of miR-222-3p on the proliferation and invasion ability of OS cells. Luciferase reporter gene assays were used to confirm the target gene of miR-222-3p in OS cells. Tumor xenografts were then used to investigate the role of miR-222-3p in OS growth in vivo.

RESULTS

The data of the present study demonstrated that miR-222-3p levels were increased in OS tissues and OS cells. Downregulation of miR-222-3p significantly inhibited the proliferation, migration, and invasion of OS cells in vitro. Further analysis revealed that tissue inhibitors of metalloproteinases 3 (TIMP3) is one of the functional target genes of miR-222-3p, and inhibition of TIMP3 efficiently rescues the blocking of cell proliferation and invasion mediated by miR-222-3p inhibitor in OS cells.

CONCLUSION

Our findings constitute evidence that miR-222-3p promotes OS cell proliferation and invasion through targeting TIMP3 mRNA and provide novel insight into the mechanism underlying the development of OS.

MicroRNA-27a alleviates LPS-induced acute lung injury in mice via inhibiting inflammation and apoptosis through modulating TLR4/MyD88/NF-κB pathway

Acute lung injury (ALI) is a critical clinical condition with a high mortality rate, characterized with excessive uncontrolled inflammation and apoptosis. Recently, microRNAs (miRNAs) have been found to play crucial roles in the amelioration of various inflammation-induced diseases, including ALI. However, it remains unknown the biological function and regulatory mechanisms of miRNAs in the regulation of inflammation and apoptosis in ALI. The aim of this study is to identify and evaluate the potential role of miRNAs in ALI and reveal the underlying molecular mechanisms of their effects. Here, we analyzed microRNA expression profiles in lung tissues from LPS-challenged mice using miRNA microarray. Because microRNA-27a (miR-27a) was one of the miRNAs being most significantly downregulated, which has an important role in regulation of inflammation, we investigated its function. Overexpression of miR-27a by agomir-27a improved lung injury, as evidenced by the reduced histopathological changes, lung wet/dry (W/D) ratio, lung microvascular permeability and apoptosis in the lung tissues, as well as ameliorative survival of ALI mice. This was accompanied by the alleviating of inflammation, such as the reduced total BALF cell and neutrophil counts, decreased levels of tumor necrosis factor alpha (TNF-α), interleukin-1 (IL-6) interleukin-1β (IL-1β) and myeloperoxidase (MPO) activity in BAL fluid. Toll-like receptor 4 (TLR4), an important regulator of the nuclear factor kappa-B (NF-κB) signaling pathway, was identified as a novel target of miR-27a in RAW264.7 cells. Furthermore, our results showed that LPS stimulation increased the expression of MyD88 and NF-κB p65 (p-p65), but inhibited the expression of inhibitor of nuclear factor-κB-α (IκB-α), suggesting the activation of NF-κB signaling pathway. Further investigations revealed that agomir-miR-27a reversed the promoting effect of LPS on NF-κB signaling pathway. The results here suggested that miR-27a alleviates LPS-induced ALI in mice via reducing inflammation and apoptosis through blocking TLR4/MyD88/NF-κB activation.

miRNAs in immune responses to Mycobacterium tuberculosis infection

Tuberculosis (TB) is one of the most fatal infectious diseases, affecting one third of the world's population. The causative agent, Mycobacterium tuberculosis (Mtb), has a well-established ability to circumvent the host's immune system for its long-term intracellular survival. MicroRNAs (miRNAs) are crucial post-transcriptional regulators of immune response. They act by negatively regulating the expression levels of important genes in both innate and adaptive immunity. It has been established in recent studies that the host immune response against Mtb is regulated by many miRNAs, most of which are induced by Mtb infection. Moreover, differential expression of miRNA in tuberculosis (TB) patients may help distinguish between TB patients and healthy individuals or latent TB. In this review, we present the recent advancements on the miRNA regulation of the host responses against Mtb infection, as well as the potential of miRNAs to as biomarkers for TB diagnosis.

miRNAs reshape immunity and inflammatory responses in bacterial infection

Pathogenic bacteria cause various infections worldwide, especially in immunocompromised and other susceptible individuals, and are also associated with high infant mortality rates in developing countries. MicroRNAs (miRNAs), small non-coding RNAs with evolutionarily conserved sequences, are expressed in various tissues and cells that play key part in various physiological and pathologic processes. Increasing evidence implies roles for miRNAs in bacterial infectious diseases by modulating inflammatory responses, cell penetration, tissue remodeling, and innate and adaptive immunity. This review highlights some recent intriguing findings, ranging from the correlation between aberrant expression of miRNAs with bacterial infection progression to their profound impact on host immune responses. Harnessing of dysregulated miRNAs in bacterial infection may be an approach to improving the diagnosis, prevention and therapy of infectious diseases.

Changes in production of tiny cellular RNAs in response to bacterial infection could guide the development of better diagnostics and therapies. MicroRNAs regulate other genes by binding to messenger RNA strands and controlling their translation into proteins. Xikun Zhou, Min Wu and colleagues of the University of North Dakota have now reviewed current knowledge about how microRNA levels shift during infection with various bacterial pathogens. These microRNAs can modulate the immune response as well as pathways that influence metabolic activity and cell survival. Increasing studies have indicated that shifts in microRNA levels in response to different infections could provide a potential bacterial ‘fingerprint’ for achieving accurate diagnosis. With deeper insight into how different microRNAs influence infection, it might one day day become possible to target these molecules with ‘antisense’ or ‘agonist’ drugs that modulate their activity.

miRNAs in Tuberculosis: New Avenues for Diagnosis and Host-Directed Therapy

Tuberculosis (TB) is one of the most fatal infectious diseases and a leading cause of mortality, with 95% of these deaths occurring in developing countries. The causative agent, Mycobacterium tuberculosis (Mtb), has a well-established ability to circumvent the host's immune system for its intracellular survival. microRNAs (miRNAs) are small, non-coding RNAs having an important function at the post-transcriptional level and are involved in shaping immunity by regulating the repertoire of genes expressed in immune cells. It has been established in recent studies that the innate immune response against TB is significantly regulated by miRNAs. Moreover, differential expression of miRNA in Mtb infection can reflect the disease progression and may help distinguish between active and latent TB infection (LTBI). These findings encouraged the application of miRNAs as potential biomarkers. Similarly, active participation of miRNAs in modulation of autophagy and apoptosis responses against Mtb opens an exciting avenue for the exploitation of miRNAs as host directed therapy (HDT) against TB. Nanoparticles mediated delivery of miRNAs to treat various diseases has been reported and this technology has a great potential to be used in TB. In reality, this exploitation of miRNAs as biomarkers and in HDT is still in its infancy stage, and more studies using animal models mimicking human TB are advocated to assess the role of miRNAs as biomarkers and therapeutic targets. In this review, we attempt to summarize the recent advancements in the role of miRNAs in TB as immune modulator, miRNAs' capability to distinguish between active and latent TB and, finally, usage of miRNAs as therapeutic targets against TB.

Synthesis of a Cleaved Form of Osteopontin by THP-1 Cells and Its Alteration by Phorbol 12-Myristate 13-Acetate and BCG Infection

The protease-cleaved osteopontin (OPN) was proposed to enhance the migration of memory T cells to granulomas in tuberculosis. Various forms of OPN were identified in human monocytic THP-1 cells stimulated by phorbol 12-myristate 13-acetate (PMA). Antibodies O-17, 10A16 and 34E3, which recognize N-terminus, the C-half, and thrombin-cleaved site of OPN, respectively, all detected distinct bands on Western blots following PMA stimulation. Bands corresponding to 18 and 30 kD were detected by antibodies 34E3 and 10A16, indicating that OPN cleavage occurred by endogenous proteases in the PMA-stimulated THP-1 cells. In immune-fluorescence (IF) assay, 34E3 positive signals were detected in intracellular space of non-infected and bacillus Calmette-Guérin (BCG)-infected cells; however, 10A16 positive signals were confirmed in extracellular area in PMA-stimulated cells followed by BCG infection. Small amounts of full-length (FL) and thrombin-cleaved (Tr) OPN were detected by ELISA in the supernatants of non-PMA-stimulated cells, and increased levels of all forms, including undefined (Ud) OPN, in PMA-stimulated cells. ELISA showed a decrease in OPN synthesis during BCG infection. To our knowledge, this is the first report of OPN cleavage in THP-1 macrophages after PMA stimulation, and of enhanced cleavage induced by BCG infection.

Clinical relevance of LINC00152 and its variants in western Chinese tuberculosis patients

Recent studies indicate that the long intergenic non-coding RNA LINC00152 plays crucial roles in various human diseases. Here, we investigated whether levels of LINC00152 or its genetic variants correlate with the clinical features of tuberculosis (TB) in western Chinese patients. We genotyped the single nucleotide polymorphism LINC00152 rs80292941 in 476 TB patients and 475 healthy subjects using a custom-by-design 48-Plex SNPscan Kit, and measured relative levels of LINC00152 using RT-qPCR. We observed that LINC00152 levels were lower in TB patients than controls. Moreover, rs80292941 TT genotype carriers had the lowest LINC00152 levels among TB patients, and rs80292941 AA genotype carriers are more likely to suffer from hepatotoxicity induced by antituberculosis therapy [OR = 3.97, 95% = 1.53-10.13, p = 0.002]. Our findings strongly suggest that LINC00152 may promote TB progression and highlight rs80292941 single nucleotide polymorphism as a novel predisposition marker for antituberculosis drug-induced hepatotoxicity.

Sphingosine-1-phosphate suppresses chondrosarcoma metastasis by upregulation of tissue inhibitor of metalloproteinase 3 through suppressing miR-101 expression

Chondrosarcoma is the second most common primary malignancy form of bone cancer, exhibiting resistance to chemotherapy and radiation therapy as well as developing high metastasis ability in late‐stage tumors. Thus, understanding the metastatic processes of chondrosarcoma is considered a strategy for the treatment of this disease. Sphingosine 1‐phosphate (S1P), a bioactive sphingolipid, is produced intracellularly by sphingosine kinase (SphK) and is regarded as a second signaling molecule that regulates inflammation, proliferation, angiogenesis, and metastasis. However, the effect of S1P on chondrosarcoma remains uncertain. As demonstrated by the transwell, immunoblotting, and real‐time PCR analyses, we found that S1P inhibited cell migration and MMP‐2 expression through the upregulation of the tissue inhibitor of metalloproteinase‐3 (TIMP‐3) expression in human chondrosarcoma cells. Additionally, we also showed that microRNA (miRNA)‐101, which targets the 3′ untranslated region (3′UTR) of TIMP‐3, decreased significantly following S1P treatment. After transfection with miR‐101 mimics, the S1P‐regulated cell migration and TIMP‐3 expression were both reversed. Furthermore, we also showed that the S1P‐inhibited cell migration is mediated through the c‐Src/MEK/ERK signaling axis. Meanwhile, the in vivo study indicated that overexpression of SphK1 decreases chondrosarcoma metastasis to the lungs. Our results illustrate the clinical significance between SphK1, TIMP‐3, and miR‐101 in human chondrosarcoma patients. Taken together, our results suggest that S1P and miR‐101 may prove to be potential therapeutic targets for future chondrosarcoma treatment.

Molecular mechanism of miR-181b in heart disease due to pregnancy-induced hypertension syndrome

The present study aimed to investigate the molecular mechanisms of microRNA (miR)-181b in heart disease due to hypertensive disorders complicating pregnancy (HDCP) through regulating the expression of metallopeptidase inhibitor 3 (TIMP3). miR-181b expression was detected by reverse transcription-quantitative polymerase chain reaction in peripheral blood samples from patients with HDCP. These samples were analyzed for clinical pathological characteristics. The primary cardiomyocytes of rats were cultured in hypoxic conditions for 24 h, in which miR-181b expression was detected at different time points. The expression of TIMP3 was assessed in normal rat cardiomyocytes following transfection with miR-181b mimics by western blot analysis. The TIMP3 protein was also detected in cardiomyocytes following transfection with TIMP3 short interfering-RNA. The apoptosis rate of transfected cardiomyocytes was detected by flow cytometry following 24 h of culture in a hypoxic environment. Luciferase assay was applied to validate whether miR-181b binds to the 3' untranslated region of TIMP3 mRNA. miR-181b expression was significantly downregulated in the peripheral blood of patients with HDCP and the miR-181b expression was negatively associated with the grades of hypertension (P<0.05). The results of luciferase assay indicated that miR-181b directly targets TIMP3. The apoptosis rates of rat cardiomyocytes in the group transfected with miR-181b or TIMP3 siRNA was significantly lower than the normal control group (P<0.05). miR-181b may inhibit apoptosis of cardiomyocytes to protect myocardial cells through directly targeting TIMP3 genes, which serve important roles in HDCP.

The Balance Between Metalloproteinases and TIMPs: Critical Regulator of Microvascular Endothelial Cell Function in Health and Disease

Endothelial cells (EC), especially the microvascular EC (MVEC), have critical functions in health and disease. For example, healthy MVEC provide a barrier between the fluid and protein found within the blood, and the surrounding tissue. Following tissue injury or infection, the microvascular barrier is often disrupted due to activation and dysfunction of the MVEC. Multiple mechanisms promote MVEC activation and dysfunction, including stimulation by cytokines, mechanical interaction with activated leukocytes, and exposure to harmful leukocyte-derived molecules, which collectively result in a loss of MVEC barrier function. However, MVEC activation is also critical to facilitate recruitment of inflammatory cells, such as neutrophils (PMNs) and monocytes, into the injured or infected tissue. Metalloproteinases, including the matrix metalloproteinases (MMPs) and the closely related, a disintegrin and metalloproteinases (ADAMs), have been implicated in regulating both MVEC barrier function, through cleavage of adherens and tight junctions proteins between adjacent MVEC and through degradation of the extracellular matrix, as well as PMN-MVEC interaction, through shedding of cell surface PMN receptors. Moreover, the tissue inhibitors of metalloproteinases (TIMPs), which collectively inhibit most MMPs and ADAMs, are critical regulators of MVEC activation and dysfunction through their ability to inhibit metalloproteinases and thereby promote MVEC stability. However, TIMPs have been also found to modulate MVEC function through metalloproteinase-independent mechanisms, such as regulation of vascular endothelial growth factor signaling. This chapter is focused on examining the role of the metalloproteinases and TIMPs in regulation of MVEC function in both health and disease.

TLR-4/miRNA-32-5p/FSTL1 signaling regulates mycobacterial survival and inflammatory responses in Mycobacterium tuberculosis-infected macrophages

Macrophages play a pivotal role in host immune response against mycobacterial infection, which is tightly modulated by multiple factors, including microRNAs. The purpose of the present study was to investigate the biological function and potential mechanism of miR-32-5p in human macrophages during Mycobacterium tuberculosis (M.tb) infection. The results demonstrated that miR-32-5p was robustly enhanced in THP-1 and U937 cells in response to M.tb infection. TLR-4 signaling was required for upregulation of miR-32-5p induced by M.tb infection. Additionally, the introduction of miR-32-5p strongly increased the survival rate of intracellular mycobacteria, whereas inhibition of miR-32-5p suppressed intracellular growth of mycobacteria during M.tb challenged. Furthermore, forced expression of miR-32-5p dramatically attenuated the accumulation of inflammatory cytokines IL-1β, IL-6 and TNF-α induced by M.tb infection. Conversely, downregulated expression of miR-32-5p led to enhancement in these inflammatory cytokines. More importantly, our study explored that Follistatin-like protein 1 (FSTL1) was a direct and functional target of miR-32-5p. qRT-PCR and western blot analysis further validated that miR-32-5p negatively regulated the expression of FSTL1. Mechanistically, re-expression of FSTL1 attenuated the ability of miR-32-5p to promote mycobacterial survival. Meanwhile, miR-32-5p-mediated inhibition of the inflammatory cytokine production were completely reversed by overexpression of FSTL1. Collectively, our findings demonstrated a novel role of TLR-4/miRNA-32-5p/FSTL1 in the modulation of host defense against mycobacterial infection, which may provide a better understanding of the pathogenesis of tuberculosis and useful information for developing potential therapeutic interventions against the disease.

Modulation of Host miRNAs by Intracellular Bacterial Pathogens

MicroRNAs (miRNAs) are short non-coding RNAs that regulate the expression of protein coding genes of viruses and eukaryotes at the post-transcriptional level. The eukaryotic genes regulated by miRNAs include those whose products are critical for biological processes such as cell proliferation, metabolic pathways, immune response, and development. It is now increasingly recognized that modulation of miRNAs associated with biological processes is one of the strategies adopted by bacterial pathogens to survive inside host cells. In this review, we present an overview of the recent findings on alterations of miRNAs in the host cells by facultative intracellular bacterial pathogens. In addition, we discuss how the altered miRNAs help in the survival of these pathogens in the intracellular environment.