MiR-27-3p regulates TLR2/4-dependent mouse alveolar macrophage activation by targetting PPARγ

Noncoding RNAs in chronic obstructive pulmonary disease: From pathogenesis to therapeutic targets

Chronic obstructive pulmonary disease (COPD) is the most prevalent chronic respiratory disorder that is becoming the leading cause of morbidity and mortality on a global scale. There is an unmet need to investigate the underlying pathophysiological mechanisms and unlock novel therapeutic avenues for COPD. Recent research has shed light on the significant roles played by diverse noncoding RNAs (ncRNAs), including microRNAs (miRNAs), long noncoding RNAs (lncRNAs), and circular RNAs (circRNAs), in orchestrating the development and progression of COPD. This review provides an overview of the regulatory roles of ncRNAs in COPD, elucidating their underlying mechanisms, and illuminating the potential prospects of RNA-based therapeutics in the management of COPD.

Macrophage polarization in spinal cord injury repair and the possible role of microRNAs: A review

The prevention, treatment, and rehabilitation of spinal cord injury (SCI) have always posed significant medical challenges. After mechanical injury, disturbances in microcirculation, edema formation, and the generation of free radicals lead to additional damage, impeding effective repair processes and potentially exacerbating further dysfunction. In this context, inflammatory responses, especially the activation of macrophages, play a pivotal role. Different phenotypes of macrophages have distinct effects on inflammation. Activation of classical macrophage cells (M1) promotes inflammation, while activation of alternative macrophage cells (M2) inhibits inflammation. The polarization of macrophages is crucial for disease healing. A non-coding RNA, known as microRNA (miRNA), governs the polarization of macrophages, thereby reducing inflammation following SCI and facilitating functional recovery. This study elucidates the inflammatory response to SCI, focusing on the infiltration of immune cells, specifically macrophages. It examines their phenotype and provides an explanation of their polarization mechanisms. Finally, this paper introduces several well-known miRNAs that contribute to macrophage polarization following SCI, including miR-155, miR-130a, and miR-27 for M1 polarization, as well as miR-22, miR-146a, miR-21, miR-124, miR-223, miR-93, miR-132, and miR-34a for M2 polarization. The emphasis is placed on their potential therapeutic role in SCI by modulating macrophage polarization, as well as the present developments and obstacles of miRNA clinical therapy.

PPARγ inhibits small airway remodeling through mediating the polarization homeostasis of alveolar macrophages in COPD

The role of Peroxisome Proliferator-Activated Receptor-γ (PPARγ) in alveolar macrophages(AMs) polarization homeostasis is closely associated with airway remodeling in COPD, but the definite mechanism remains unclear. In this study, elevated percentage of M1-type AMs and the expression of functionally cytokines were found in COPD patients and mice, which closely related to the disease severity. PPARγ was markedly up-regulated in M2-type AMs and down-regulated in M1-type AMs, and was associated with disease severity in COPD. Co-cultured with M1- or M2-type AMs promoted the epithelial-mesenchymal transition (EMT) of airway epithelial cells and the proliferation of airway smooth muscle cells. Moreover, airway remodeling and functional damage were observed in both IL4R-/- COPD mice with runaway M1-type AMs polarization and TLR4-/- COPD mice with runaway M2-type AMs polarization. Cigarette extract (CS) or lipopolysaccharide (LPS) stimulated PPARγ-/- AMs showed more serious polarization disorder towards M1, as well as CS induced PPARγ-/- COPD mice, which led to more severe airway inflammation, lung function damage, and airway remodeling. Treatment with PPARγ agonist significantly improved the polarization disorder and function activity in CS/LPS stimulated-AMs by inhibiting the JAK-STAT, MAPK and NF-κB pathways, and alleviated the airway inflammation, restored the lung function and suppressed airway remodeling in CS induced-COPD mice. Our research demonstrates that polarization homeostasis of AMs mediated by PPARγ has the protective effect in airway remodeling, and may be a novel therapeutic target for the intervention and treatment of airway remodeling in COPD.

miRNA-Induced Downregulation of IPMK in Macrophages Mediates Lipopolysaccharide-Triggered TLR4 Signaling

Inositol polyphosphate multikinase (IPMK) is a pleiotropic enzyme responsible for the production of inositol polyphosphates and phosphoinositide. IPMK in macrophages was identified as a key factor for the full activation of the Toll-like receptor 4 (TLR4) signaling pathway and inflammation by directly interacting with tumor necrosis factor receptor-associated factor 6 (TRAF6). Here, dynamic changes of IPMK levels in lipopolysaccharide (LPS)-stimulated macrophages and their functional significance were investigated. Both the mRNA and protein levels of IPMK were acutely decreased in mouse and human macrophages when cells were stimulated with LPS for between 1 and 6 h. Analysis of the 3' untranslated region (UTR) of mouse IPMK mRNA revealed a highly conserved binding site for miR-181c. Transfection of miR-181c mimics into RAW 264.7 macrophages led to decreased IPMK 3'UTR-luciferase reporter activity and lowered endogenous IPMK levels. When the genomic deletion of a 33-bp fragment containing a putative miR-181c-binding site was introduced within the IPMK 3'UTR of RAW 264.7 macrophages (264.7^Δ3'UTR), LPS-triggered downregulation of IPMK levels was prevented. LPS treatment in 264.7^Δ3'UTR macrophages decreased TLR4-induced signaling and the expression of proinflammatory cytokines. In response to LPS stimulation, K63-linked ubiquitination of TRAF6 was impaired in 264.7^Δ3'UTR macrophages, suggesting an action of IPMK in the suppression of TRAF6 activation. Therefore, our findings reveal that LPS-mediated suppression of IPMK regulates the full activation of TLR4 signaling and inflammation in macrophages.

MiR-29b level-mediated regulation of Klotho methylation via DNMT3A targeting in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a chronic lung disease characterized by chronic bronchitis and emphysema. Cigarette smoke extract (CSE) is the predominant cause of COPD. This study aimed to investigate the effects of miR-29b and their underlying mechanisms in a COPD cell model. MiR-29b and DNMT3A expression in lung tissue samples (taken at least 5 cm away from the tumor lesion) of NSCLC cases with smoking (n = 30), without smoking (n = 30), and with COPD (with smoking) (n = 30) was researched by qRT-PCR. A medium containing 10 % CSE was employed to induce murine alveolar macrophage MH-S cells to establish COPD cells. 5-Aza-cdr (5-AZA-2'-deoxycytidine) was used to block DNMT3A. The relationship and interaction between miR-29b and DNMT3A were validated through the dual luciferase reporter assay. The expression levels of macrophage M1 polarization marker proteins iNOS and TNF-α, DNMT3A, and Klotho protein were monitored using western blotting. The methylation levels of the miR-29b precursor gene and Klotho promoter were detected by quantitative methylation-specific PCR (MS-qPCR). The levels of IL-1β, IL-6, and TNF-α in cell culture medium were detected via ELISA. It was found that the expression of miR-29b was downregulated, as a result of increased DNA methylation, and that of DNMT3A was upregulated in the lung tissues of NSCLC cases with COPD (with smoking). DNMT3A expression was negatively correlated with miR-29b expression in the lung tissues of NSCLC cases with COPD (with smoking). In addition, miR-29b expression was distinctly downregulated in CSE-induced MH-S cells and inhibited CSE-induced M1 polarization and inflammation. Importantly, DNMT3A was identified as a direct target gene of miR-29b. MiR-29b is negatively regulated by DNMT3A-mediated DNA methylation. Moreover, Klotho expression was downregulated and the Klotho promoter methylation level was increased in lung tissues of NSCLC cases with COPD (with smoking). The negative feedback between miR-29b and DNMT3A modulates CSE-induced M1 polarization and inflammation in macrophages as well as Klotho promoter methylation in CSE-mediated MH-S. Collectively, these findings indicate that the miR-29b level in COPD controls Klotho methylation via DNMT3, which maybe a promising target for the treatment of COPD.

Comprehensive analysis of immune parameters, mRNA and miRNA profiles, and immune genes expression in the gill of rainbow trout infected with infectious hematopoietic necrosis virus (IHNV)

Rainbow trout (Oncorhynchus mykiss) is a species of cold-water fish with important economic values, widely cultivated worldwide. However, the outbreak of infectious hematopoietic necrosis virus (IHNV) caused the large-scale death of rainbow trout and seriously restricted the development of the trout farming industry. In this study, the changes of immune parameters in different periods (6-, 12-, 24-, 48-, 72-, 96-, 120-, and 144 h post-infection (hpi)), transcriptome profiles of 48 hpi (T48G) compared to control (C48G), and key immune-related genes expression patterns were measured in rainbow trout gill following IHNV challenge through biochemical methods, RNA sequencing (RNA-seq), and quantitative real-time polymerase chain reaction (qRT-PCR). The results showed that alkaline phosphatase (AKP), acid phosphatase (ACP), total superoxide dismutase (T-SOD), alanine aminotransferase (ALT), and aspartate aminotransferase (AST) activities, as well as lysozyme (LZM) and malonaldehyde (MDA) content decreased and then increased during infection, and remained at a high level after 48 hpi (P < 0.05), whereas catalase (CAT) activity showed a significant peak at 48 hpi (P < 0.05). The mRNA and miRNA analysis identified 4343 differentially expressed genes (DEGs) and 11 differentially expressed miRNAs (DEMs), and numerous immune-related DEGs involved in the Toll-like receptor signaling pathway, apoptosis, DNA replication, p53 signaling, RIG-I-like receptor signaling pathway, and NOD-like receptor signaling pathway and expression were significantly up-regulated in T48Gm group, including tlr3, tlr7, tlr8, traf3, ifih1, trim25, dhx58, ddh58, hsp90a.1, nlrc3, nlrc5, socs3, irf3, irf7, casp7, mx1, and vig2. The integrated analysis identified several important miRNAs (ola-miR-27d-3p_R+5, gmo-miR-124-3-5p, ssa-miR-301a-5p_L+2, and ssa-miR-146d-3p) that targeted key immune-related DEGs. Expression analysis showed that tlr3, tlr7, traf3, ifih1, dhx58, hap90a.1, irf3, irf7, and mx1 genes increased and then decreased during infection, and peaked at 72 hpi (P < 0.05). However, trim25 expression peaked at 96 hpi (P < 0.05). This study contributes to understanding immune response of rainbow trout against IHNV infection, and provides new insights into the immune regulation mechanisms and disease resistance breeding studies.

Alveolar Macrophages Participate in the Promotion of Influenza Virus Infection by Aflatoxin B1 at an Early Stage

Aflatoxin B1 (AFB1), one of the most common environmental mycotoxin contaminations in food and feed, poses significant threats to human and animal health. Our previous study indicated that even non-toxic AFB1 concentrations could promote influenza virus replication and induce influenza virus-infected alveolar macrophages polarizing from M1 (immunostimulatory phenotype) to M2 (immunosuppressive phenotype) over time. However, whether AFB1 promotes influenza replication via modulating the polarization of alveolar macrophages is unknown. Here, we specifically depleted alveolar macrophages using clodronate-containing liposomes in swine influenza virus (SIV)-infected mice to explore the mechanism the promotion of SIV replication by AFB1. The results show that the depletion of alveolar macrophages significantly alleviated the AFB1-induced weight loss, inflammatory responses, and lung and immune organ damage of the SIV-infected mice after 14 days and greatly diminished the AFB1-promoted SIV replication. In contrast, the depletion of alveolar macrophages did not alleviate the AFB1-induced weight loss, and lung and immune organ damage of the SIV-infected mice after 28 days and slightly diminished the AFB1-promoted SIV replication. Collectively, the data indicate that alveolar macrophages play a crucial role the promotion of SIV infection by AFB1 in the early rather than late stage, and AFB1 can promote SIV replication by inducing alveolar macrophages to polarize towards M1 macrophages. This research provides novel targets for reducing the risk of AFB1-promoted influenza virus infection.

Non-Coding RNAs in Airway Diseases: A Brief Overview of Recent Data

Inflammation of the human lung is mediated in response to different stimuli (e.g., physical, radioactive, infective, pro-allergenic, or toxic) such as cigarette smoke and environmental pollutants. These stimuli often promote an increase in different inflammatory activities in the airways, manifesting themselves as chronic diseases (e.g., allergic airway diseases, asthma chronic bronchitis/chronic obstructive pulmonary disease, or even lung cancer). Non-coding RNA (ncRNAs) are single-stranded RNA molecules of few nucleotides that regulate the gene expression involved in many cellular processes. ncRNA are molecules typically involved in the reduction of translation and stability of the genes of mRNAs s. They regulate many biological aspects such as cellular growth, proliferation, differentiation, regulation of cell cycle, aging, apoptosis, metabolism, and neuronal patterning, and influence a wide range of biologic processes essential for the maintenance of cellular homeostasis. The relevance of ncRNAs in the pathogenetic mechanisms of respiratory diseases has been widely established and in the last decade many papers were published. However, once their importance is established in pathogenetic mechanisms, it becomes important to further deepen the research in this direction. In this review we describe several of most recent knowledge concerning ncRNA (overall miRNAs) expression and activities in the lung.

The role of HMGB1/RAGE/TLR4 signaling pathways in cigarette smoke-induced inflammation in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a common chronic respiratory disease with irreversible and continuous progression. It has become the fifth most burdensome disease and the third most deadly disease globally. Therefore, the prevention and treatment of COPD are urgent, and it is also important to clarify the pathogenesis of it. Smoking is the main and most common risk factor for COPD. Cigarette smoke (CS) can cause lung inflammation and other pathological mechanisms in the airways and lung tissue. Airway inflammation is one of the important mechanisms leading to the pathogenesis of COPD. Recent studies have shown that high mobility group box 1 (HMGB1) is involved in the occurrence and development of respiratory diseases, including COPD. HMGB1 is a typical damage-associated molecular pattern (DAMP) protein, which mainly exerts its activity by binding to the receptor for advanced glycation end products (RAGE) and toll-like receptor 4 (TLR4) and further participate in the process of airway inflammation. Studies have shown that the abnormal expression of HMGB1, RAGE, and TLR4 are related to inflammation in COPD. Herein, we discuss the roles of HMGB1, RAGE, and TLR4 in CS/cigarette smoke extract-induced inflammation in COPD, providing a new target for the diagnosis, treatment and prevention of COPD.

Diabetes exacerbated sepsis-induced intestinal injury by promoting M1 macrophage polarization via miR-3061/Snail1 signaling

Background

Macrophages play important roles in diabetes and sepsis-related intestinal injury. Accumulating evidence suggests that microRNAs (miRNAs) act as the fundamental link between macrophage polarization and tissue injury. However, the underlying mechanisms of miRNAs in regulating macrophage polarization–related intestinal injury under diabetes and sepsis conditions remain unclear.

Methods

The cecal ligation and puncture (CLP)–induced sepsis models were established in male wild-type (WT) and diabetic mice. Clodronate liposome was used to deplete macrophage. H&E staining, inflammatory cytokines [tumor necrosis factor–α (TNF-α), interleukin-1β (IL-1β), and IL-6], and intestinal mucosal barrier function markers [occludin, ZO-1, lipopolysaccharide (LPS), and intestinal fatty acid binding protein (iFABP)] were used to assess elevated intestinal damage. miRNA array, RNA-seq, and bioinformatic analysis were performed to detect the miRNA and messenger RNA (mRNA) expression and the potential regulation mechanism. In vitro, RAW264.7 cells were cultured in the absence or presence of high glucose and LPS, miR-3061 mimics, and Snail small interfering RNA stimulation, respectively, for further mechanism studies. Luciferase reporter assay was used to confirm the interplay between miRNA and its target genes.

Results

Compared with WT CLP mice, the diabetic CLP mice showed severe intestinal damage characterized by significant increases in Chui’s scores, expression of inflammatory cytokines (TNF-α, IL-1β, and IL-6), serum LPS and iFABP concentration, and significant reductions in tight junction protein occludin and ZO-1 levels. Macrophage depletion reversed the intestinal damage caused by CLP. The bioinformatic analysis revealed that miR-3061/Snail1 might be a potential regulation axis of macrophage polarization. Furthermore, high glucose and LPS stimulation increased M1 macrophage and reduced the levels of miR-3061, which was negatively associated with Snail1 in RAW264.7 cells. Mechanistic studies demonstrated that miR-3061 regulated macrophage polarization by targeting the Snail1 mRNA 3′‐untranslated region. Moreover, miR-3061 overexpression suppressed Snail1 expression and inhibited M1 macrophage and inflammatory cytokines.

Conclusion

This study elucidated that diabetes exacerbated sepsis-induced intestinal injury by promoting M1 macrophage polarization and further demonstrated that the miR-3061/Sani1 axis may be the potential target of macrophage polarization.

Local and systemic inflammation triggers different outcomes of tumor growth related to infiltration of anti-tumor or pro-tumor macrophages

BACKGROUND

Previous evidence suggests inflammation may be a double-edged sword with cancer-promoting and cancer suppressing function. In this study, we explore the impact of local and systemic inflammation on cancer growth.

METHODS

Female BALB/C mice were subcutaneously implanted with foreign body (plastic plates) to build up a local inflammation and intraperitoneally injected with PolyIC or lipopolysaccharides (LPS) to build up a systemic inflammation, followed by subcutaneous injection of 5  × 10 5 colon cancer cells. Immunohistochemistry and enzyme linked immunosorbent assay were utilized to detect the Ki67 and interleukin (IL) 6, IL-1β, and monocyte chemoattractant protein-1 expression in the tumor tissues and serum, respectively. The distributions of immune cells and expression of toll-like receptors (TLRs) were evaluated by flow cytometry (FCM) and quantitative real time-polymerase chain reaction.

RESULTS

The results showed that local inflammation induced by foreign body implantation suppressed tumor growth with decreased tumor weight ( P   =  0.001), volume ( P   =  0.004) and Ki67 index ( P   <  0.001). Compared with the control group, myeloid-derived suppressive cells sharply decreased ( P   =  0.040), while CD4 + T cells slightly increased in the tumor tissues of the group of foreign body-induced local inflammation ( P   =  0.035). Moreover, the number of M1 macrophages ( P   =  0.040) and expression of TLRs, especially TLR3 ( P  < 0.001) and TLR4 ( P  < 0.001), were significantly up-regulated in the foreign body group. Contrarily, tumor growth was significantly promoted in LPS or PolyIC-induced systemic inflammation ( P   =  0.009 and 0.006). FCM results showed M1 type macrophages ( P   =  0.017 and 0.006) and CD8 + T cells ( P   =  0.031 and 0.023) were decreased, while M2 type macrophages ( P  = 0.002 and 0.007) were significantly increased in tumor microenvironment of LPS or PolyIC-induced systemic inflammation group. In addition, the decreased expression of TLRs was detected in LPS or PolyIC group.

CONCLUSIONS

The foreign body-induced local inflammation inhibited tumor growth, while LPS or PolyIC- induced systemic inflammation promoted tumor growth. The results suggested that the different outcomes of tumor growth might be attributed to the infiltration of anti-tumor or pro-tumor immune cells, especially M1 or M2 type macrophages into tumor microenvironment.

Essential Oils of Gardenia jasminoides J. Ellis and Gardenia jasminoides f. longicarpa Z.W. Xie & M. Okada Flowers: Chemical Characterization and Assessment of Anti-Inflammatory Effects in Alveolar Macrophage

Alveolar macrophage is the predominant cell type in the lung and is thought to be the major target for anti-inflammatory therapy in chronic obstructive pulmonary disease (COPD). Aromatherapy using natural essential oils with anti-inflammatory effects for inhalable administration is a potential complementary and alternative therapy for COPD treatment. The Gardenia jasminoides flower is famous for its fragrance in East Asia and is used for treating colds and lung problems in folk medicine. Therefore, in the present study, flower essential oils from two main medicinal gardenia varieties (G. jasminoides J. Ellis and G. jasminoides f. longicarpa Z.W. Xie & M. Okada) were extracted by hydro-distillation, and their chemical components were analyzed by GC-MS. The anti-inflammatory effects of the two essential oils and their main ingredients were further studied on lipopolysaccharide (LPS)-induced models in murine alveolar macrophages (MH-S). The results indicated that the chemical constituents of the two gardenia varieties were quite different. Alcohol accounted for 53.8% of the G. jasminoides essential oil, followed by terpenes (16.01%). Terpenes accounted for 34.32% of the G. jasminoides f. longicarpa essential oil, followed by alcohols (19.6%) and esters (13.85%). Both the two gardenia essential oils inhibited the LPS-induced nitric oxide (NO) release and reduced the production of tumor necrosis factor-α (TNF-α) and prostaglandin E2 (PGE2) in the MH-S cells. Linalool and α-farnesene dose-dependently reduced the NO release in the MH-S cells. Linalool and α-farnesene did not affect the PGE2 production but regulated the expression of TNF- α. In addition to linalool and α-farnesene, other components in the gardenia flower essential oils appeared to be able to act as anti-inflammatory agents and influence the PGE2 pathway.

Exosomal microRNAs induce tumor-associated macrophages via PPARγ during tumor progression in SHH medulloblastoma

Medulloblastoma (MB), the most common malignant pediatric brain tumor, is composed of at least four molecular subgroups with distinct clinical characteristics. The sonic hedgehog (SHH) subgroup exhibits the most abundant tumor-associated microglia/macrophages (TAMs) infiltration. SHH-MB patients treated by anti-SHH drugs showed high drug resistance. However, the comprehensive role of TAMs in SHH-MB remains enigma. The aim of this study is to explore the mechanism of TAM activation/polarization in SHH-MB and discover a potential immunotherapeutic target to reduce drug resistance. We first analyzed expression profiles of immuno-microenvironment (IME) in four subgroups of 48 MB tumors using NanoString PanCancer IO360 panel and found TAMs were the major component of IME in SHH-MBs. We further distinguished M1/M2-like TAMs in tumors and found M2-like macrophages, rather than microglia, were enriched in SHH-MBs. In transgenic SHH-MB mice, these TAMs had close relationship with tumor progression. Polarization of the TAMs could be induced by MB-derived exosomes in vitro. We then screened SHH MB-derived exosomal miRNAs and their target genes using RNA sequencing and luciferase assay to clarify their roles in regulating TAM polarization. We found down-regulated let-7i-5p and miR-221-3p can induce M2-like polarization of TAMs via upregulating peroxisome proliferator activated receptor gamma (PPARγ). Finally, we demonstrated the PPARγ antagonist efficiently improved the antitumor activity of SMO inhibitor in vivo, which may be related to inhibition of M2-like TAMs. Our findings suggest a potential therapeutic strategy for SHH-MB by targeting tumor-supportive M2-like TAMs to enhance the therapeutic effect of SMO inhibitors.

Tetrahedral-Framework Nucleic Acids Carry Small Interfering RNA to Downregulate Toll-Like Receptor 2 Gene Expression for the Treatment of Sepsis

Sepsis is caused by the invasion of pathogenic microorganisms, which can lead to excessive expression of toll-like receptors (TLRs) in cells and uncontrollable amplification of the inflammatory response. TLR2, as an essential part of the TLR family, has a significant feature in the identification of innate immune responses. Therefore, blocking the expression and activation of TLR2 can inhibit the synthesis and release of inflammatory factors and avoid the occurrence of excessive inflammatory reactions. Small interfering RNA (siRNA) can selectively target the silencing or downregulation of pathogenic genes and has the advantages of high specificity, a strong effect, and fewer adverse reactions. However, the application of siRNA is limited by its high molecular weight, poor biostability, and difficulty in passive uptake into cells. Tetrahedral-framework nucleic acid (tFNA) is a new kind of three-dimensional nucleic acid nanomaterial, which has the advantages of good biocompatibility, stable structure, and editability. In this study, we used tFNA as carriers to deliver siRNA-targeting downregulation of TLR2 expression for anti-inflammatory therapy. We show that siRNA can specifically reduce lipopolysaccharide (LPS)-induced TLR2 elevation and reduce release of inflammatory factors in LPS-induced experimental sepsis, which provides a new idea for the prevention and treatment of sepsis.

microRNA-27a-3p but Not -5p Is a Crucial Mediator of Human Adipogenesis

MicroRNAs (miRNAs), a class of small, non-coding RNA molecules, play an important role in the posttranscriptional regulation of gene expression, thereby influencing important cellular functions. In adipocytes, miRNAs show import regulatory features and are described to influence differentiation as well as metabolic, endocrine, and inflammatory functions. We previously identified miR-27a being upregulated under inflammatory conditions in human adipocytes and aimed to elucidate its function in adipocyte biology. Both strands of miR-27a, miR-27a-3p and -5p, were downregulated during the adipogenic differentiation of Simpson–Golabi–Behmel syndrome (SGBS) cells, human multipotent adipose-derived stem cells (hMADS), and human primary adipose-derived stromal cells (hASCs). Using miRNA-mimic transfection, we observed that miR-27a-3p is a crucial regulator of adipogenesis, while miR-27a-5p did not alter the differentiation capacity in SGBS cells. In silico screening predicted lipoprotein lipase (LPL) and peroxisome proliferator activated receptor γ (PPARγ) as potential targets of miR-27a-3p. The downregulation of both genes was verified in vitro, and the interaction of miR-27-3p with target sites in the 3′ UTRs of both genes was confirmed via a miRNA-reporter-gene assay. Here, the knockdown of LPL did not interfere with adipogenic differentiation, while PPARγ knockdown decreased adipogenesis significantly, suggesting that miR-27-3p exerts its inhibitory effect on adipogenesis by repressing PPARγ. Taken together, we identified and validated a crucial role for miR-27a-3p in human adipogenesis played by targeting the essential adipogenic transcription factor PPARγ. Though we confirmed LPL as an additional target of miR-27a-3p, it does not appear to be involved in regulating human adipogenesis. Thereby, our findings call the conclusions drawn from previous studies, which identified LPL as a crucial regulator for murine and human adipogenesis, into question.

CircPrkcsh, a circular RNA, contributes to the polarization of microglia towards the M1 phenotype induced by spinal cord injury and acts via the JNK/p38 MAPK pathway

Spinal cord injury (SCI) is a complex pathological change that includes primary SCI and gradually evolves into secondary SCI. Accumulating evidence demonstrates that circular RNAs (circRNAs) are involved in the pathology of a variety of neurological diseases and injuries. However, the characteristics and function of circRNAs in SCI have yet to be elucidated. Although previous research demonstrated that circPrkcsh induces astrocytes to produce inflammatory factors and chemokines, the precise function and mechanism of circPrkcsh in microglia after SCI remains unknown. In this study, we constructed a mouse model of SCI by applying a SCI impactor. Quantitative Real-time PCR and Fluorescence in situ hybridization analysis revealed that circPrkcsh was upregulated in the microglia of SCI mice when compared to sham-operated mice. Gain- or loss-of-function experiments and in vivo assays further indicated that circPrkcsh promotes microglia M1 polarization both in vivo and in vitro. Furthermore, bioinformatics analysis, dual-luciferase assays, and RNA immunoprecipitation assays, confirmed that circPrkcsh serves as a competing endogenous RNA (ceRNA) to promote the expression of MEKK1 mRNA by sponging miR-488. Double knockout rescue experiments further showed that circPrkcsh regulates the MEKK1/JNK/p38 MAPK pathway via miR-488. Our research provides a better understanding of the mechanism of circPrkcsh in SCI and demonstrates that the circPrkcsh/miR-488/Mekk1 axis is a promising regulatory method for the treatment of SCI.

miRNAomics analysis reveals the promoting effects of cigarette smoke extract-treated Beas-2B-derived exosomes on macrophage polarization

Inhalation of cigarette smoke induces airway and parenchyma inflammation that predisposes smokers to multiple lung diseases such as COPD. Macrophage polarization, an important specifying feature of inflammation, is involved in the progression of pulmonary inflammation. Exosomes and their loaded miRNAs provide a medium for cross-talk between alveolar macrophages and lung epithelial cells to maintain lung homeostasis. In this study, we treated Beas-2B with CSE to speculate the effects of Beas-2B-derived exosomes on macrophage polarization and performed exosomal miRNAomics analysis to explore the mechanism. We found that CSE-treated Beas-2B-derived exosomes could not only increase the percentages of CD86⁺, CD80⁺ CD163⁺, and CD206⁺ cells but also induce the secretion of TNF-α, IL-6, iNOS, IL-10, Arg-1, and TGF-β, indicating both M1 and M2 polarization of RAW264.7 macrophages were promoting. We performed miRNAomics analysis to identify 27 differentially expressed exosomal miRNAs such as miR-29a-3p and miR-1307-5p. Next, we obtained 14942 target genes of these miRNAs such as SCN1A and PLEKHA1 through the prediction of TargetScan and miRanda. We utilized KEGG enrichment analysis for these targets to identify potential pathways such as the PI3K-Akt signaling pathway and the MAPK signaling pathway on the regulation of macrophage polarization. We further found that miR-21-3p or miR-27b-3p may play critical roles in the promotion of CSE-Exo on macrophage polarization by miRNA interference. Collectively, this study provided novel information for diagnostic and therapeutic tactics of cigarette smoke-related lung diseases.

Rosiglitazone ameliorated airway inflammation induced by cigarette smoke via inhibiting the M1 macrophage polarization by activating PPARγ and RXRα

BACKGROUND

Rosiglitazone, an exogenous ligand of PPARγ, plays an important anti-inflammatory role during the inflammation caused by cigarette smoke (CS). CS exposure induces pulmonary inflammation via activating macrophage polarization. However, the effects of rosiglitazone on macrophage polarization induced by CS are unclear.

METHODS

36 male Wistar rats were randomly divided into 3 groups: control, CS and ROSI. In the CS group, rats were passively exposed to cigarette smoke for consecutive 3 months. In the ROSI group, rats were treated with rosiglitazone (3 mg/kg/day, ip) during CS exposure period. Alveolar macrophages of rats were isolated and cultured with CSE. The slices of lung tissues were stained with hematoxylin and eosin. The histomorphology was observed to evaluate emphysema and the pulmonary function was detected. Cells in bronchoalveolar lavage fluid (BALF) were examined and the expression of cytokines TNF-α and IL-1β was detected by ELISA and qPCR. The alveolar macrophage polarization was evaluated by immunohistochemistry and flow cytometry assay in vivo and by qPCR in vitro. The protein level of PPARγ and RXRα was measured by Western blot.

RESULTS

CS exposure induced significant emphysema, diminished FEV0.2/FVC, elevated PEF, and higher level of total cells, neutrophils and cytokines (TNF-α and IL-1β) in BALF compared with control group, whereas rosiglitazone partly ameliorated above disorders. CS exposure activated M1 and M2 macrophage polarization in vivo and in vitro, whereas rosiglitazone inhibited CS induced M1 macrophage polarization and decreased the ratio of M1/M2. The effects of rosiglitazone on macrophage polarization were partly blocked after AMs treated with the antagonists of PPARγ and RXRα, and were synergistically enhanced by the agonist of RXRα. CS exposure decreased the expression of PPARγ and RXRα in lung tissues and AMs, and rosiglitazone partly reversed CS-mediated suppression of PPARγ and RXRα.

CONCLUSION

Rosiglitazone ameliorated the emphysema and inflammation in lung tissues induced by CS exposure via inhibiting the M1 macrophage polarization through activating PPARγ and RXRα.

miR-27-3p Enhances the Sensitivity of Triple-Negative Breast Cancer Cells to the Antitumor Agent Olaparib by Targeting PSEN-1, the Catalytic Subunit of Γ-Secretase

Olaparib has been used in the treatment of triple-negative breast cancer (TNBC) with BRCA mutations. In the present study, we demonstrated the effect of miR-27-3p on the γ-secretase pathway by regulating the sensitivity of TNBC cells to olaparib. miR-27-3p, a microRNA with the potential to target PSEN-1, the catalytic subunit of γ-secretase mediating the second step of the cleavage of the Notch protein, was identified by the online tool miRDB and found to inhibit the expression of PSEN-1 by directly targeting the 3'-untranslated region (3'-UTR) of PSEN-1. The overexpression of miR-27-3p inhibited the activation of the Notch pathway via the inhibition of the cleavage of the Notch protein, mediated by γ-secretase, and, in turn, enhanced the sensitivity of TNBC cells to the antitumor agent olaparib. Transfection with PSEN-1 containing mutated targeting sites for miR-27-3p or the expression vector of the Notch protein intracellular domain (NICD) almost completely blocked the effect of miR-27-3p on the Notch pathway or the sensitivity of TNBC cells to olaparib, respectively. Therefore, our results suggest that the miR-27-3p/γ-secretase axis participates in the regulation of TNBC and that the overexpression of miR-27-3p represents a potential approach to enhancing the sensitivity of TNBC to olaparib.

Serum Exosomal microRNA-27-3p Aggravates Cerebral Injury and Inflammation in Patients with Acute Cerebral Infarction by Targeting PPARγ

Acute cerebral infarction (ACI) possesses high mortality. Exosomes present in serum have potential application value in ACI diagnosis. This study investigated the mechanism of serum exosomes in ACI. Serum exosomes isolated from ACI patients and normal people were identified and then injected into the established middle cerebral artery occlusion (MCAO) rat model to evaluate cerebral injury and inflammation. Exosomal microRNA (miR)-27-3p expression was detected and interfered to analyze rat cerebral inflammation. The binding relationship between miR-27-3p and PPARγ was predicted and verified. The lipopolysaccharide (LPS)-treated microglia model was established and intervened with miR-27-3p to detect PPARγ, Iba-1, and inflammation-related factor expressions. After overexpressing PPARγ, rat cerebral inflammation was evaluated. The clinical significance of serum exosomal miR-27-3p in ACI was evaluated. Serum exosomes from ACI patients caused exacerbated MCAO rat cerebral injury and poor behavior recovery, as well as promoted cerebral inflammation. Serum exosomal miR-27-3p deepened rat brain inflammation. miR-27-3p targeted PPARγ to promote microglia activation and inflammation-related factor expressions in MCAO rats, and overexpressing PPARγ attenuated MCAO rat cerebral inflammation. Serum exosomal miR-27-3p promised to be a biomarker for ACI. We proved that serum exosomes from ACI patients aggravated ACI patient cerebral inflammation via the miR-27-3p/PPARγ axis.

Harnessing noncoding RNA-based macrophage polarization: Emerging therapeutic opportunities for fibrosis

Aim

Organ fibrosis is a common pathological outcome of persistent tissue injury correlated with organ failure and death. Although current antifibrotic therapies have led to unprecedented successes, only a minority of patients with fibrosis benefit from these treatments. There is an urgent need to identify new targets and biomarkers that could be exploited in the diagnosis and treatment of fibrosis.

Methods

Macrophages play a dual role in the fibrogenesis across different organs either by promoting pro‐inflammatory or anti‐inflammatory responses. Noncoding RNAs (ncRNAs) have been demonstrated to play key roles in macrophage functions by manipulating macrophage polarization. Therefore, understanding the mechanism of ncRNA‐associated macrophage polarization is important to move toward therapeutic interventions.

Results

In this review, we provide an overview of recent insights into the role of ncRNAs in different fibrotic diseases by modulating macrophage phenotypic plasticity and functional heterogeneity. We also discuss the potential mechanisms of different ncRNAs integrate heterogeneous macrophages in fibrogenesis,including regulatory signatures, networks, and reciprocal interactions.

Conclusions

A broader understanding of how ncRNA‐directed macrophage phenotype transition in immunity and fibrosis might promote the development of a novel strategy for antifibrotic treatment.

Impact of Anticoagulation and Sample Processing on the Quantification of Human Blood-Derived microRNA Signatures

Blood-derived microRNA signatures have emerged as powerful biomarkers for predicting and diagnosing cardiovascular disease, cancer, and metabolic disorders. Platelets and platelet-derived microvesicles are a major source of microRNAs. We have previously shown that the inappropriate anticoagulation and storage of blood samples causes substantial platelet activation that is associated with the release of platelet-stored molecules into the plasma. However, it is currently unclear if circulating microRNA levels are affected by artificial platelet activation due to suboptimal plasma preparation. To address this issue, we used a standardized RT-qPCR test for 12 microRNAs (thrombomiR^®, TAmiRNA GmbH, Vienna, Austria) that have been associated with cardiovascular and thrombotic diseases and were detected in platelets and/other hematopoietic cells. Blood was prevented from coagulating with citrate–theophylline–adenosine–dipyridamole (CTAD), sodium citrate, or ethylenediaminetetraacetic acid (EDTA) and stored for different time periods either at room temperature or at 4 °C prior to plasma preparation and the subsequent quantification of microRNAs. We found that five microRNAs (miR-191-5p, miR-320a, miR-21-5p, miR-23a-3p, and miR-451a) were significantly increased in the EDTA plasma. Moreover, we observed a time-dependent increase in plasma microRNAs that was most pronounced in the EDTA blood stored at room temperature for 24 h. Furthermore, significant correlations between microRNA levels and plasma concentrations of platelet-stored molecules pointed towards in vitro platelet activation. Therefore, we strongly recommend to (i) use CTAD as an anticoagulant, (ii) process blood samples as quickly as possible, and (iii) store blood samples at 4 °C whenever immediate plasma preparation is not feasible to generate reliable data on blood-derived microRNA signatures.

Type III Secretion Protein, PcrV, Impairs Pseudomonas aeruginosa Biofilm Formation by Increasing M1 Macrophage-Mediated Anti-bacterial Activities

Pseudomonas aeruginosa biofilms employ a variety of strategies to hijack the host immune defense system to achieve chronic infection. However, the bacterial components that are involved in this process are not yet fully understood. PcrV, a needle tip protein of the P. aeruginosa type III secretion system (T3SS), was downregulated during P. aeruginosa biofilm infection. The impaired expression of the P. aeruginosa pcrV gene is associated with attenuated immune activation and an increased percentage of M2 macrophages following P. aeruginosa biofilm infection. Treatment with exogenous PcrV produced from Escherichia coli elevated tissue inflammation and the percentage of M1 macrophages, resulting in reduction in the biofilm burden. Further analyses demonstrated that the potential of PcrV to induce classically activated M1 macrophages as evidenced by the increased production of proinflammatory cytokines and anti-bacterial mediators, including inducible nitric oxide synthase (iNOS) and reactive oxygen species (ROS), as well as increased phagocytosis of bacteria. Mechanistically, PcrV-mediated promotion of macrophage M1 polarization and phagocytosis occurs through the activation of mitogen-activated protein kinases (MAPKs) and NF-κB signaling pathways. Collectively, these findings reveal a potential role of PcrV in skewing host immune defense to promote P. aeruginosa biofilm infection and provide new insights into the therapeutic strategies for P. aeruginosa biofilm infection.

MicroRNAs in chronic airway diseases: Clinical correlation and translational applications

MicroRNAs (miRNAs) are short single-stranded RNAs that have pivotal roles in disease pathophysiology through transcriptional and translational modulation of important genes. It has been implicated in the development of many diseases, such as stroke, cardiovascular conditions, cancers and inflammatory airway diseases. There is recent evidence that miRNAs play important roles in the pathogenesis of asthma and chronic obstructive pulmonary disease (COPD), and could help to distinguish between T2-low (non-eosinophilic, steroid-insensitive) versus T2-high (eosinophilic, steroid-sensitive) disease endotypes. As these are the two most prevalent chronic respiratory diseases globally, with rising disease burden, miRNA research might lead to the development of new diagnostic and therapeutic targets. Research involving miRNAs in airway disease is challenging because: (i) asthma and COPD are heterogeneous inflammatory airway diseases; there are overlapping but distinct inter- and intra-disease differences in the immunological pathophysiology, (ii) there exists more than 2000 known miRNAs and a single miRNA can regulate multiple targets, (iii) differential effects of miRNAs could be present in different cellular subtypes and tissues, and (iv) dysregulated miRNA expression might be a direct consequence of an indirect effect of airway disease onset or progression. As miRNAs are actively secreted in fluids and remain relatively stable, they have the potential for biomarker development and therapeutic targets. In this review, we summarize the preclinical data on potential miRNA biomarkers that mediate different pathophysiological mechanisms in airway disease. We discuss the framework for biomarker development using miRNA and highlight the need for careful patient characterization and endotyping in the screening and validation cohorts, profiling both airway and blood samples to determine the biological fluids of choice in different disease states or severity, and adopting an untargeted approach. Collaboration between the various stakeholders - pharmaceutical companies, laboratory professionals and clinician-scientists is crucial to reduce the difficulties and cost required to bring miRNA research into the translational stage for airway diseases.

Epigenetic Modifications and Therapy in Chronic Obstructive Pulmonary Disease (COPD): An Update Review

Chronic obstructive pulmonary disease (COPD) that is one of the most prevalent chronic adult diseases and the third leading cause of fatality until 2020. Elastase/anti-elastase hypothesis, chronic inflammation, apoptosis, oxidant-antioxidant balance and infective repair cause pathogenesis of COPD are among the factors at play. Epigenetic changes are post-translational modifications in histone proteins and DNA such as methylation and acetylation as well as dysregulation of miRNAs expression. In this update review, we have examined recent studies on the upregulation or downregulation of methylation in different genes associated with COPD. Dysregulation of HDAC activity which is caused by some factors and miRNAs plays a key role in the suppression and reduction of COPD development. Also, some therapeutic approaches are proposed against COPD by targeting HDAC2 and miRNAs, which have therapeutic effects.

Therapeutic RNA Strategies for Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) is characterized by airflow limitation with persistent respiratory symptoms. Current therapeutics for COPD are largely borrowed from the drug armamentarium for the treatment of asthma, which has different pathophysiological mechanisms from COPD. COPD has been linked to dysregulated expression of mRNAs and noncoding (nc)RNAs including miRNAs, PIWI-interacting (pi)RNAs, long noncoding (lnc)RNAs, and circular (circ)RNAs. This review highlights and discusses some recent advances towards development of RNA therapeutics for COPD.

Chronic myeloid leukemia-derived exosomes attenuate adipogenesis of adipose derived mesenchymal stem cells via transporting miR-92a-3p

Cancer-associated cachexia (CAC) has tremendous effects on the patient's tolerance to chemotherapy and the quality of life, especially in the advanced stages, such as the acute and terminal stages of chronic myeloid leukemia (CML). However, the underlying mechanisms and mediators remain unclear. Here, we showed that mice injected with CML-derived exosomes had significant weight loss and great drop of body fat rate. In the meanwhile, we found that CML-derived exosomes could be taken up by adipose tissue, and, in turn, suppressed the adipogenic ability of adipose-derived mesenchymal stem cells (ADSCs). By RNA sequencing, miR-92a-3p was found highly expressed in both CML cells and the derivative exosomes. Mechanistically, miR-92a-3p inhibited adipogenesis of ADSCs via posttranscriptionally decreasing C/EBPα expression when transferred into the ADSCs with the exosomes, and encapsulating miR-92a-3p inhibitor into CML exosomes blocked the antiadipogenic effects of CML exosomes. In addition, we also found that miR-92a-3p was highly expressed in exosomes from some other types of cancers that cause cachexia. These results demonstrate that adipogenesis inhibition by tumor-derived exosomes, mainly exosomal microRNAs like miR-92a-3p, are the main mediators for CAC.

Zoledronic acid promotes TLR-4-mediated M1 macrophage polarization in bisphosphonate-related osteonecrosis of the jaw

Bisphosphonate-related osteonecrosis of the jaw (BRONJ) is a detrimental side effect of the long-term administration of bisphosphonates. Although macrophages were reported to be an important mediator of BRONJ, the detailed potential mechanism of BRONJ remains unclear. Here, we reported an elevated TLR-4 expression in macrophages under action of zoledronic acid (ZA), resulting in enhanced M1 macrophage polarization and decreased M2 macrophage polarization both in vitro and in vivo. After inhibiting the TLR-4 signaling pathway, the activation of the TLR-4/NF-κB signaling pathway and the induction of NF-κB nuclear translocation and production of proinflammatory cytokines by ZA were suppressed in macrophages, thereby inhibiting M1 macrophage polarization. By utilizing the TLR-4^-/- mice, development of BRONJ was markedly ameliorated, and M1 macrophages were significantly attenuated in the extraction socket tissues in the TLR-4^-/- mice. Importantly, the systemic administration of the TLR-4 inhibitor TAK-242 improved the wound healing of the extraction socket and decreased the incidence rate of BRONJ. Taken together, our findings suggest that TLR-4-mediated macrophage polarization participates in the pathogenesis of BRONJ in mice, and TLR-4 may be a potential target for the prevention and therapeutic treatment of BRONJ.-Zhu, W., Xu, R., Du, J., Fu, Y., Li, S., Zhang, P., Liu, L., Jiang, H. Zoledronic acid promotes TLR-4-mediated M1 macrophage polarization in bisphosphonate-related osteonecrosis of the jaw.