LPS induces CXCL16 expression in HUVECs through the miR-146a-mediated TLR4 pathway

Influence of sex and liver cirrhosis on the expression of miR-146a-5p and its target genes, IRAK1 and TRAF6

Long-term alcohol misuse triggers cellular adaptions in susceptible regions of the human brain, resulting in neurodegeneration, neuroinflammation and altered gene expression. Previous studies have identified ∼35 miRNAs, including miR-146a-5p, which are up-regulated in the frontal cortex of males with alcohol use disorder (AUD), but the influence of liver cirrhosis and sex is unknown. The expression of miR-146a-5p, IRAK1, and TRAF6 was measured in the prefrontal cortex of controls and individuals with AUD with and without cirrhosis of the liver. Further, individuals were genotyped for two SNPs, rs2910164 and rs57095329. The expression of miR-146a-5p was significantly different between sexes. In males the expression of miR-146a-5p was increased in individuals with AUD with and without liver cirrhosis compared with controls. In females miR-146a-5p expression was significantly lower in individuals with AUD compared with both controls and those with AUD and cirrhosis, suggesting that both the severity of alcohol misuse and the sex of the individual influences the expression of miR-146a-5p. The expression of TRAF6 was significantly lower in individuals with uncomplicated AUD compared with those with AUD and cirrhosis. The expression of IRAK1 did not differ between groups or sexes. There was no influence of genotype on expression. Increased expression of miR-146a-5p did not correlate with decreased IRAK1 or TRAF6 expression suggesting a loss of regulatory control of the TLR4 pathway. Understanding sex-specific differences in the regulation of gene expression in AUD is key to determine which inflammatory pathways could be targeted for therapeutic intervention.

CXCL16 exacerbates Pseudomonas aeruginosa keratitis by promoting neutrophil activation

Pseudomonas aeruginosa (PA) keratitis is a major cause of blindness characterized by corneal inflammation. In a murine model of PA keratitis, we assessed the detrimental effects of CXC chemokine ligand 16 (CXCL16). Quantitative PCR (qPCR), western blotting (WB) and immunofluorescence were used to measure the expression and localization of CXCL16 and its receptor, CXC chemokine receptor 6 (CXCR6). Clinical scores, plate counting, and hematoxylin-eosin staining were used to assess infection severity and its exacerbation by CXCL16. Immunofluorescence, myeloperoxidase assays, and flow cytometry were used to detect neutrophil activity and colocalization with CXCR6. WB and immunofluorescence were used to measure levels of reactive oxygen species (ROS) and matrix metalloproteinases (MMPs). These methods also were used to measure the activation of downstream NF-κB signaling and its positive feedback on CXCL16 expression. ELISA, flow cytometry, and qPCR were used to measure the expression of CXCL2 and T helper 17 (Th17) cell-related genes. CXCL16 and CXCR6 expression was increased in infected corneas. Topical application of CXCL16 exacerbated keratitis by increasing corneal bacterial load and promoting neutrophil infiltration, whereas neutralizing antibody against CXCL16 had the opposite effect. CXCL16 also increased ROS and MMP levels. This neutrophil activation may be caused by its positive feedback with the NF-κB pathway and the upregulation of CXCL2 and Th17 cell related-genes. These data suggest that CXCL16 is an attractive therapeutic target for PA keratitis.

Targeting IL-17A enhances imatinib efficacy in Philadelphia chromosome-positive B-cell acute lymphoblastic leukemia

Dysregulated hematopoietic niches remodeled by leukemia cells lead to imbalances in immunological mediators that support leukemogenesis and drug resistance. Targeting immune niches may ameliorate disease progression and tyrosine kinase inhibitor (TKI) resistance in Philadelphia chromosome-positive B-ALL (Ph+ B-ALL). Here, we show that T helper type 17 (Th17) cells and IL-17A expression are distinctively elevated in Ph+ B-ALL patients. IL-17A promotes the progression of Ph+ B-ALL. Mechanistically, IL-17A activates BCR-ABL, IL6/JAK/STAT3, and NF-kB signalling pathways in Ph+ B-ALL cells, resulting in robust cell proliferation and survival. In addition, IL-17A-activated Ph+ B-ALL cells secrete the chemokine CXCL16, which in turn promotes Th17 differentiation, attracts Th17 cells and forms a positive feedback loop supporting leukemia progression. These data demonstrate an involvement of Th17 cells in Ph+ B-ALL progression and suggest potential therapeutic options for Ph+ B-ALL with Th17-enriched niches.

E. coli LPS/TLR4/NF-κB Signaling Pathway Regulates Th17/Treg Balance Mediating Inflammatory Responses in Oral Lichen Planus

Oral lichen planus (OLP) is a chronic inflammatory autoimmune disease mediated by T cells. The imbalance of microflora has potential impacts on the onset and development of OLP, but the mechanism is still unclear. Here, we investigated the effects of Escherichia coli (E. coli) lipopolysaccharide (LPS) simulating the microbial enrichment state of OLP on T cell immune functions in vitro. Effect of E. coli LPS on the viability of T cell using CCK8 assay. After E. coli LPS pretreatment, the expression of the toll-like receptor 4 (TLR4), nuclear factor-kappa B p65 (NF-κB p65), cytokines, retinoic acid-related orphan receptor γt (RORγt), and forkhead box p3 (Foxp3) in the peripheral blood of OLP patients and normal controls (NC) were assessed using quantitative RT-PCR (qRT-PCR), western blot, and enzyme-linked immunosorbent assay (ELISA). Finally, Th17 and Treg cells were detected by flow cytometry. We found that the TLR4/NF-κB pathway was activated and the expression of interleukin (IL)-6 and IL-17 was increased in both groups after E. coli LPS stimulation. CC chemokine ligand (CCL)20 and CC chemokine receptor (CCR)4 expression was increased in OLP after E. coli LPS treatment, while no difference was found in CCR6 and CCL17 expression of both groups. Moreover, E. coli LPS treatment enhanced the proportion of Th17 cells, Th17/Treg ratio, and RORγt/Foxp3 ratio in OLP. In conclusion, E. coli LPS regulated Th17/Treg balance to mediate the inflammatory responses of OLP through the TLR4/NF-κB pathway in vitro, indicating that oral microbiota dysbiosis affected the chronic inflammatory state of OLP.

Gut Molecules in Cardiometabolic Diseases: The Mechanisms behind the Story

Atherosclerotic cardiovascular disease is the most common cause of morbidity and mortality worldwide. Diabetes mellitus increases cardiovascular risk. Heart failure and atrial fibrillation are associated comorbidities that share the main cardiovascular risk factors. The use of incretin-based therapies promoted the idea that activation of alternative signaling pathways is effective in reducing the risk of atherosclerosis and heart failure. Gut-derived molecules, gut hormones, and gut microbiota metabolites showed both positive and detrimental effects in cardiometabolic disorders. Although inflammation plays a key role in cardiometabolic disorders, additional intracellular signaling pathways are involved and could explain the observed effects. Revealing the involved molecular mechanisms could provide novel therapeutic strategies and a better understanding of the relationship between the gut, metabolic syndrome, and cardiovascular diseases.

EPSTI1 promotes monocyte adhesion to endothelial cells in vitro via upregulating VCAM-1 and ICAM-1 expression

Atherosclerosis is a chronic inflammatory disease of arterial wall, and circulating monocyte adhesion to endothelial cells is a crucial step in the pathogenesis of atherosclerosis. Epithelial-stromal interaction 1 (EPSTI1) is a novel gene, which is dramatically induced by epithelial-stromal interaction in human breast cancer. EPSTI1 expression is not only restricted to the breast but also in other normal tissues. In this study we investigated the role of EPSTI1 in monocyte-endothelial cell adhesion and its expression pattern in atherosclerotic plaques. We showed that EPSTI1 was dramatically upregulated in human and mouse atherosclerotic plaques when compared with normal arteries. In addition, the expression of EPSTI1 in endothelial cells of human and mouse atherosclerotic plaques is significantly higher than that of the normal arteries. Furthermore, we demonstrated that EPSTI1 promoted human monocytic THP-1 cell adhesion to human umbilical vein endothelial cells (HUVECs) via upregulating VCAM-1 and ICAM-1 expression in HUVECs. Treatment with LPS (100, 500, 1000 ng/mL) induced EPSTI1 expression in HUVECs at both mRNA and protein levels in a dose- and time-dependent manner. Knockdown of EPSTI1 significantly inhibited LPS-induced monocyte-endothelial cell adhesion via downregulation of VCAM-1 and ICAM-1. Moreover, we revealed that LPS induced EPSTI1 expression through p65 nuclear translocation. Thus, we conclude that EPSTI1 promotes THP-1 cell adhesion to endothelial cells by upregulating VCAM-1 and ICAM-1 expression, implying its potential role in the development of atherosclerosis.

Functions and therapeutic interventions of non-coding RNAs associated with TLR signaling pathway in atherosclerosis

Nowadays, emerging data demonstrate that the toll-like receptor (TLR) signaling pathway plays an important role in the progression of inflammatory atherosclerosis. Indeed, dysregulated TLR signaling pathway could be a cornerstone of inflammation and atherosclerosis, which contributes to the development of cardiovascular diseases. It is interesting to note that this pathway is heavily controlled by several mechanisms, such as epigenetic factors in which the role of non-coding RNAs (ncRNAs), particularly microRNAs and long noncoding RNAs as well as circular RNAs in the pathogenesis of atherosclerosis has been well studied. Recent years have seen a significant surge in the amount of research exploring the interplay between ncRNAs and TLR signaling pathway downstream targets in the development of atherosclerosis; however, there is still considerable room for improvement in this field. The current study was designed to review underlying mechanisms of TLR signaling pathway and ncRNA interactions to shed light on therapeutic implications in patients with atherosclerosis.

Regulatory Networks, Management Approaches, and Emerging Treatments of Nonalcoholic Fatty Liver Disease

The pathogenesis of NAFLD is complex and diverse, involving multiple signaling pathways and cytokines from various organs. Hepatokines, stellakines, adipokines, and myokines secreted by hepatocytes, hepatic stellate cells, adipose tissue, and myocytes play an important role in the occurrence and development of nonalcoholic fatty liver disease (NAFLD). The nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) contributes to the progression of NAFLD by mediating liver inflammation, immune response, hepatocyte death, and later compensatory proliferation. In this review, we first discuss the crosstalk and interaction between hepatokines, stellakines, adipokines, and myokines and NF-κB in NAFLD. The characterization of the crosstalk of NF-κB with these factors will provide a better understanding of the molecular mechanisms involved in the progression of NAFLD. In addition, we examine new expert management opinions for NAFLD and explore the therapeutic potential of silymarin in NAFLD/NASH.

Paradoxical attenuation of neuroinflammatory response upon LPS challenge in miR-146b deficient mice

The miR-146 family consists of two microRNAs (miRNAs), miR-146a and miR-146b (miR-146a/b), both of which are known to suppress immune responses in a variety of conditions. Here, we studied how constitutive deficiency of miR-146b (Mir146b-/-) affects lipopolysaccharide (LPS)-induced neuroinflammation in mice. Our experiments demonstrated that miR-146b deficiency results in the attenuation of LPS-induced neuroinflammation, as it was evidenced by the reduction of sickness behavior, a decrease in the inflammatory status of microglia, and the loss of morphological signs of microglial activation in the hippocampus. Gene expression analysis revealed that LPS-induced upregulation of hippocampal pro-inflammatory cytokines is attenuated in Mir146b-/- mice, compared to wild-type (WT) mice. In addition, reduced expression of the NF-κB nuclear protein p65, reduced miR-146 family target TLR4 expression and relatively stronger upregulation of miR-146a was found in Mir146b-/- mice as compared to WT mice upon LPS challenge. Compensatory upregulation of miR-146a can explain the attenuation of the LPS-induced neuroinflammation. This was supported by experiments conducted with miR-146a/b deficient mice (Mir146a/b-/-), which demonstrated that additional deletion of the miR-146a led to the restoration of LPS-induced sickness behavior and proinflammatory cytokines. Our experiments also showed that the observed upregulation of miR-146a in Mir146b-/- mice is due to the overexpression of a miR-146a transcription inducer, interferon regulatory factor 7 (Irf7). Altogether, our results show the existence of crosstalk between miR-146a and mir-146b in the regulation of LPS-induced neuroinflammation.

miR-146-5p restrains calcification of vascular smooth muscle cells by suppressing TRAF6

Vascular calcification is a prominent manifestation of advanced atherosclerosis. Tumor necrosis factor-receptor-associated factors (TRAFs) were reported to participate in atherosclerosis development. In this study, the role and mechanism of TRAF6 in vascular calcification were explored. To induce the vascular calcification, oxidized low-density lipoprotein (Ox-LDL) was applied to treat vascular smooth muscle cells (VSMCs). TRAF6 protein expression in VSMCs was assessed by western blotting. Osteogenic differentiation of VSMCs was assessed by alkaline phosphatase activity analysis. Mineral deposition in VSMCs was evaluated by von Kossa staining. VSMC proliferation, migration, apoptosis, inflammation, and reactive oxygen species (ROS) generation were detected using cell counting kit-8, Transwell, flow cytometry, reverse transcriptase quantitative polymerase chain reaction (RT-qPCR), and dichlorodihydrofluorescein diacetate staining, respectively. Luciferase reporter assay was utilized to identify the binding relationship between miR-146-5p and TRAF6 in VSMCs. We found that Ox-LDL administration induced the calcification of VSMCs and elevated the TRAF6 level. TRAF6 knockdown restrained VSMC calcification, proliferation, migration, inflammation, and ROS generation caused by Ox-LDL. Mechanically, TRAF6 was targeted by miR-146-5p in VSMCs. Furthermore, TRAF6 overexpression offset the inhibitory effects of miR-146-5p upregulation on vascular calcification in VSMCs under the Ox-LDL condition. Overall, miR-146-5p restrains the calcification of VSMCs by suppressing TRAF6.

The mediating role of plasma microRNAs in the association of phthalates exposure with arterial stiffness: A panel study

Phthalates exposure has been reported to be linked with arterial stiffness. However, the biological mechanisms underlying this association remain unclear. We conducted a panel study using 338 paired urine-blood samples by repeated measurements of 123 adults across 3 seasons to assess the potential mediating role of plasma microRNAs (miRNAs) in the association of phthalates exposure with arterial stiffness. We measured 10 urinary phthalate metabolites by gas chromatography-tandem mass spectrometry (GC-MS/MS) and 5 candidate arterial stiffness-related miRNAs (miR-146a, miR-222, miR-125b, miR-126, and miR-21) in plasma by real-time PCR. Arterial stiffness parameters including brachial-ankle pulse wave velocity (baPWV) and ankle-brachial index (ABI) were determined in health examinations during each visit. Linear mixed-effect (LME) models revealed that mono-methyl phthalate (MMP), mono-iso-butyl phthalate (MiBP), mono-n-butyl phthalate (MBP), mono-n-octyl phthalate (MOP), and mono-(2-ethyl-5-carboxypentyl) phthalate (MECPP) were significantly associated with one or more of the 5 plasma miRNAs (all P_FDR < 0.05). Based on weighted quantile sum (WQS) regression, we found positive associations of phthalate metabolites mixture with miR-146a, miR-125b, and miR-222, and individual MMP and MBP were the major contributors. Additionally, miR-146a was inversely related to ABI. Mediation analysis further indicated that miR-146a mediated 31.6% and 21.3% of the relationships of MMP and MiBP with ABI, respectively. Our findings suggested that certain phthalates exposure was related to plasma miRNAs alterations in a dose-response manner and miR-146a might partly mediate phthalate-associated ABI reduction.

MicroRNA-146a-5p alleviates lipopolysaccharide-induced NLRP3 inflammasome injury and pro-inflammatory cytokine production via the regulation of TRAF6 and IRAK1 in human umbilical vein endothelial cells (HUVECs)

Background

Microribonucleic acids (miRNAs) have an evident role in regulating endothelial inflammation and dysfunction, which characterizes the early stages of atherosclerosis. The NOD-like receptor family pyrin domain-containing protein 3 (NLRP3) inflammasome has been reported to contribute to the endothelial inflammatory response that promotes atherosclerosis development and progression. This study sought to investigate the effects of miR-146a-5p on lipopolysaccharide (LPS)-induced NLRP3 inflammasome injury and pro-inflammatory cytokine production in human umbilical vein endothelial cells (HUVECs).

Methods

HUVECs were transfected with a miR-146a-5p mimic, small-interfering RNA (siRNA) (si-TRAF6, and si-IRAK1), and were then stimulated with LPS for 24 h. The messenger (mRNA) and the protein levels of p-NF-κB/NF-κB, NLRP3, Caspase-1, pro-inflammatory cytokine [interleukin (IL)-6, IL-1β and tumor necrosis factor alpha (TNF-α)] in the HUVECs were analyzed by quantitative real-time polymerase chain reactions (PCRs) and western blot assays, respectively. The secretion of IL-6 from the cells was detected by enzyme-linked immunoassay (ELISA). Bioinformatic and dual-luciferase reporter assays were performed to identify the targets of miR-146a-5p.

Results

LPS promoted pro-inflammatory cytokine expression in a dose-dependent manner and significantly increased the expression levels of p-NF-κB/NF-κB p65, NLRP3, and Caspase-1. After transfection with a miR-146a-5p mimic, or si-TRAF6 or si-IRAK1, we observed that the mRNA and protein levels of NF-κB/p-NF-κB, NLRP3, Caspase-1, and pro-inflammatory cytokine in the HUVECs were all down-regulated, and the secretion of IL-6 from cells declined significantly. After transfection with a miR-146-5p mimic, the expression of TRAF6 and IRAK1 in HUVECs were both down-regulated. Dual-luciferase reporter assays confirmed that miR-146-5p directly targets the 3'-untranslated region (3'-UTR) of TRAF6 and IRAK1 to regulate their expression.

Conclusions

As a modulator of TRAF6 and IRAK1, miR-146a-5p negatively regulated LPS-induced NF-κB activation and the NLRP3 inflammasome signaling pathway in HUVECs. Thus, miRNA-146a-5p may serve as a potential therapeutic target for atherosclerosis.

Heparin alleviates LPS-induced endothelial injury by regulating the TLR4/MyD88 signaling pathway

Heparin is a commonly used in the clinic, however, Heparin's effect on endothelial injury remains unclear. The aim of the present study was to evaluate the effects and possible mechanisms of action underlying heparin treatment in lipopolysaccharide (LPS)-induced endothelial injury in vitro. TNF-α, IL-1β, IL-6 and IFN-γ levels were measured using ELISA. Cell proliferation was measured using a 5-ethynyl-2'-deoxyuridine (EdU) assay. The number of apoptotic cells and apoptotic rate were evaluated using TUNEL assays and flow cytometry, respectively. Toll-like receptor 4 (TLR4), myeloid differentiation primary response 88 (MyD88) and NF-κB (p65) gene expression was evaluated using reverse transcription-quantitative PCR, whilst TLR4, MyD88 and p-NF-κB (p65) protein expression was evaluated using western blot analysis. The levels of phosphorylated NF-κB in the nucleus were evaluated using cellular immunofluorescence. Compared with those in the normal control group, TNF-α, IL-1β, IL-6 and IFN-γ levels were significantly increased in the LPS group (P<0.001). In addition, 5-ethynyl-2'-deoxyuridine (EdU)-positive cells were significantly increased and apoptosis was significantly decreased (P<0.001). TLR4, MyD88 and NF-κB (p65) expression was also significantly increased (P<0.001). Compared with those in the LPS group, following heparin treatment, TNF-α, IL-1β, IL-6 and IFN-γ levels were significantly decreased (P<0.05), whilst the number of EdU-positive cells was significantly increased and the level of apoptosis was significantly decreased (P<0.05). TLR4, MyD88 and NF-κB (p65) expression was also significantly decreased by heparin in a dose-dependent manner (P<0.001). Small interfering RNA-TLR4 transfection exerted similar effects to those mediated by heparin in alleviating endothelial injury. In conclusion, heparin suppressed LPS-induced endothelial injury through the regulation of TLR4/MyD88/NF-κB (p65) signaling in vitro.

MicroRNAs as Factors in Bidirectional Crosstalk Between Mitochondria and the Nucleus During Cellular Senescence

Mitochondria are essential organelles that generate most of the chemical energy to power the cell through ATP production, thus regulating cell homeostasis. Although mitochondria have their own independent genome, most of the mitochondrial proteins are encoded by nuclear genes. An extensive bidirectional communication network between mitochondria and the nucleus has been discovered, thus making them semi-autonomous organelles. The nucleus-to-mitochondria signaling pathway, called Anterograde Signaling Pathway can be deduced, since the majority of mitochondrial proteins are encoded in the nucleus, less is known about the opposite pathway, the so-called mitochondria-to-nucleus retrograde signaling pathway. Several studies have demonstrated that non-coding RNAs are essential "messengers" of this communication between the nucleus and the mitochondria and that they might have a central role in the coordination of important mitochondrial biological processes. In particular, the finding of numerous miRNAs in mitochondria, also known as mitomiRs, enabled insights into their role in mitochondrial gene transcription. MitomiRs could act as important mediators of this complex crosstalk between the nucleus and the mitochondria. Mitochondrial homeostasis is critical for the physiological processes of the cell. Disruption at any stage in their metabolism, dynamics and bioenergetics could lead to the production of considerable amounts of reactive oxygen species and increased mitochondrial permeability, which are among the hallmarks of cellular senescence. Extensive changes in mitomiR expression and distribution have been demonstrated in senescent cells, those could possibly lead to an alteration in mitochondrial homeostasis. Here, we discuss the emerging putative roles of mitomiRs in the bidirectional communication pathways between mitochondria and the nucleus, with a focus on the senescence-associated mitomiRs.

Long non-coding RNA RP11-490M8.1 inhibits lipopolysaccharide-induced pyroptosis of human umbilical vein endothelial cells via the TLR4/NF-κB pathway

BACKGROUND AND AIMS

Pyroptosis is a relatively newly discovered form of programmed cell death that plays an important role in the development of atherosclerosis. Many studies have reported that lncRNAs participated in the regulation of atherosclerosis development. However, the regulatory mechanism of lncRNAs in pyroptosis must be studied further.

METHODS

In a previous study, microarray analysis was used to detect the lncRNA expression profile in three human advanced atherosclerotic plaques and three normal arterial intimae. In the present research, in vitro assays were performed to investigate the role of lncRNA RP11-490M8.1 on pyroptosis. The relative gene mRNA and lncRNA expression levels were tested by quantitative real-time PCR, and protein levels were evaluated by western blot analysis. The RNA hybrid structure was analyzed using the DINAMelt server.

RESULTS

The lncRNA RP11-490M8.1 was significantly downregulated in atherosclerotic plaques and serum. Lipopolysaccharide (LPS) markedly reduced the expression of lncRNA RP11-490M8.1 and induced pyroptosis by increasingthe mRNA and protein levels of NLRP3, caspase-1, ASC, IL-1β, and IL-18 in HUVECs. The promotion effects ofLPS on pyroptosis were markedly suppressed by overexpression of lncRNA RP11-490M8.1. In addition, LPS increased the mRNA and protein levels ofTLR4 and NF-κB, which was also markedly offsetby overexpression of lncRNA RP11-490M8.1.

CONCLUSIONS

These findings indicated that lncRNA RP11-490M8.1 inhibited LPS-induced pyroptosis via the TLR4/NF-κB pathway. Thus, lncRNA RP11-490M8.1 may provide a therapeutic target to ameliorate atherosclerosis.

Interaction between non-coding RNAs and Toll-like receptors

Toll-like receptors (TLRs) are a large group of pattern recognition receptors which are involved in the regulation of innate immune responses. Based on the interplay between TLRs and adapter molecules, two distinctive signaling cascades, namely the MyD88-dependent and TRIF-dependent pathways have been recognized. TLRs are involved in the development of a wide variety of diseases including cancer and autoimmune disorders. A large body of evidence has shown interaction between two classes of non-coding RNAs, namely microRNAs (miRNAs) and long noncoding RNAs (lncRNAs). These interactions have prominent roles in the pathogenesis of several disorders including infectious disorders, autoimmune conditions and neoplastic disorders. This review aims at description of the interaction between these non-coding RNAs and TLRs.

The Role of CXCL16 in the Pathogenesis of Cancer and Other Diseases

CXCL16 is a chemotactic cytokine belonging to the α-chemokine subfamily. It plays a significant role in the progression of cancer, as well as the course of atherosclerosis, renal fibrosis, and non-alcoholic fatty liver disease (NAFLD). Since there has been no review paper discussing the importance of this chemokine in various diseases, we have collected all available knowledge about CXCL16 in this review. In the first part of the paper, we discuss background information about CXCL16 and its receptor, CXCR6. Next, we focus on the importance of CXCL16 in a variety of diseases, with an emphasis on cancer. We discuss the role of CXCL16 in tumor cell proliferation, migration, invasion, and metastasis. Next, we describe the role of CXCL16 in the tumor microenvironment, including involvement in angiogenesis, and its significance in tumor-associated cells (cancer associated fibroblasts (CAF), microglia, tumor-associated macrophages (TAM), tumor-associated neutrophils (TAN), mesenchymal stem cells (MSC), myeloid suppressor cells (MDSC), and regulatory T cells (T_reg)). Finally, we focus on the antitumor properties of CXCL16, which are mainly caused by natural killer T (NKT) cells. At the end of the article, we summarize the importance of CXCL16 in cancer therapy.

Long noncoding RNA metastasis-associated lung adenocarcinoma transcript 1 correlates with microRNA-125b/microRNA-146a/microRNA-203 and predicts 2-year restenosis risk in coronary heart disease patients

Aim: To investigate correlations of long noncoding RNA metastasis-associated lung adenocarcinoma transcript 1 (lnc-MALAT1) and its target microRNAs with clinical features and restenosis risk in coronary heart disease (CHD) patients post drug-eluting stent-percutaneous coronary intervention (DES-PCI). Materials & methods: A total of 274 CHD patients undergoing DES-PCI were enrolled, pre-operative plasma samples were obtained to detect lnc-MALAT1, miR-125b, miR-146a, miR-203 by RT-qPCR; 2-year restenosis was determined by quantitative coronary angiography. Results: Lnc-MALAT1 negatively correlated with miR-125b, miR-146a and miR-203. Furthermore, lnc-MALAT1, miR-125b, miR-146a and miR-203 correlated with diabetes mellitus, hyperuricemia, lesion properties, cholesterol, inflammation and cardiac function indexes. Additionally, lnc-MALAT1 was increased, while miR-125b and miR-146a were decreased in patients with 2-year restenosis than patients without 2-year restenosis; however, miR-203 did not differ. Conclusion: Lnc-MALAT1 and its target miRNAs might help manage restenosis risk in CHD patients post DES-PCI.

Inflammatory Chemokines in Atherosclerosis

Atherosclerosis is a long-term, chronic inflammatory disease of the vessel wall leading to the formation of occlusive or rupture-prone lesions in large arteries. Complications of atherosclerosis can become severe and lead to cardiovascular diseases (CVD) with lethal consequences. During the last three decades, chemokines and their receptors earned great attention in the research of atherosclerosis as they play a key role in development and progression of atherosclerotic lesions. They orchestrate activation, recruitment, and infiltration of immune cells and subsequent phenotypic changes, e.g., increased uptake of oxidized low-density lipoprotein (oxLDL) by macrophages, promoting the development of foam cells, a key feature developing plaques. In addition, chemokines and their receptors maintain homing of adaptive immune cells but also drive pro-atherosclerotic leukocyte responses. Recently, specific targeting, e.g., by applying cell specific knock out models have shed new light on their functions in chronic vascular inflammation. This article reviews recent findings on the role of immunomodulatory chemokines in the development of atherosclerosis and their potential for targeting.

Constructing a ceRNA-immunoregulatory network associated with the development and prognosis of human atherosclerosis through weighted gene co-expression network analysis

There is now overwhelming experimental and clinical evidence that atherosclerosis (AS) is a chronic inflammatory disease. The recent discovery of a new group of mediators known as competing endogenous RNA (ceRNA) offers a unique opportunity for investigating immunoregulation in AS. In this study, we used gene expression profiles from GEO database to construct a lncRNA-miRNA-mRNA ceRNA network during AS plaque development through weighted gene co-expression network analysis (WGCNA). GO annotation and pathway enrichment analysis suggested that the ceRNA network was mainly involved in the immune response. CIBERSORT and GSVA were used to calculate the immune cell infiltration score and identified macrophage as hub immunocyte in plaque development. A macrophage related ceRNA subnetwork was constructed through correlation analysis. Samples from Biobank of Karolinska Endarterectomy (BiKE) were used to identify prognostic factors from the subnetwork and yielded 7 hub factors that can predict ischemic events including macrophage GSVA score and expression value of AL138756.1, CTSB, MAFB, LYN, GRK3, and BID. A nomogram based on the key factors was established. GSEA identified that the PD1 signaling pathway was negatively associated with these prognostic factors which may explain the cardiovascular side effect of immune checkpoint therapy in anti-tumor treatment.

miR146a up-regulation is involved in small HA oligosaccharides-induced pro-inflammatory response in human chondrocytes

BACKGROUND

Small HA fragments are produced during cartilage degradation and their role seems to be preponderant during pathologies in which cartilage injury contribute to trigger and perpetuate the inflammatory mechanism. Several reports have increasingly shown that MicroRNAs (miRs), a small non-coding mRNAs are involved in the regulation of multiple biological processes, including cell proliferation and inflammation response in different pathologies, among them miR146a seems to be involved in inflammatory processes.

METHODS

Starting by these evidences we investigated the levels of miR146a and its correlation with inflammatory mediators in an experimental model of 6-mer HA-induced inflammatory response in human cultured chondrocytes.

RESULTS

Treatment of chondrocytes with 6-mer HA showed up-regulation in inflammation parameters such as TLR-4, and CD44 receptors activation, IL-6, IL-1β and MMP-13 mRNA expression and proteins production, as well as NF-kB activation. We also revealed an up-regulation of miR146a. Transfection with a miR146a mimic or miR146a inhibitor produced the following effects: chondrocytes receiving miR146a mimic and then 6-mer HA significantly reduced inflammatory cytokines and MMP-13, while exposition of chondrocytes with miR146a inhibitor and then the 6-mer HA incremented the activity of damaging cytokines and MMP13. Expression of CD44 receptor was not affected by miR-146a treatments, while TLR-4 expression and NF-kB activation were modified.

CONCLUSIONS

We concluded that up-regulation of miR146a occurred in 6-mer HA-induced inflammation response may reduce the inflammatory cascade by modulating TLR-4 and NF-kB activation.

GENERAL SIGNIFICANCE

These results could be useful in develop new therapeutic strategies with the aim to reduce OA and RA incidence.

Herbal formula LLKL ameliorates hyperglycaemia, modulates the gut microbiota and regulates the gut-liver axis in Zucker diabetic fatty rats

LLKL, a new traditional Chinese medicine formula containing Edgeworthia gardneri (Wall.) Meisn., Sibiraea angustata and Crocus sativus L. (saffron), was designed to ameliorate type 2 diabetes mellitus. Despite the therapeutic benefits of LLKL, its underlying mechanisms remain elusive. This study evaluated the LLKL anti-diabetic efficacy and its effect on gut microbiota to elucidate its mechanism of action in Zucker diabetic fatty rats. We found that administration of different LLKL concentrations (4.68, 2.34 and 1.17 g/kg/d) improved several diabetic parameters after a 6-week treatment. Moreover, LLKL modulated gut microbiota dysbiosis, increased the expression of occluding and maintained intestinal epithelial homeostasis, leading to a reduction in LPS, TNF-α and IL-6 levels. Hepatic transcriptomic analysis showed that the Toll-like receptor signalling pathway was markedly enriched by LLKL treatment. RT-qPCR results validated that LLKL treatment decreased the expressions of TLR4, MyD88 and CTSK. Furthermore, a gene set enrichment analysis indicated that LLKL enhanced the insulin signalling pathway and inhibited glycerolipid metabolism and fatty acid metabolism, which were verified by the liver biochemical analysis. These findings demonstrate that LLKL ameliorates hyperglycaemia, modulates the gut microbiota and regulates the gut-liver axis, which might contribute to its anti-diabetic effect.

Upregulated ox40l Can Be Inhibited by miR-146a-5p in Condylar Chondrocytes Induced by IL-1β and TNF-α: A Possible Regulatory Mechanism in Osteoarthritis

INTRODUCTION

Osteoarthritis (OA) is a common musculoskeletal disease characterized by pain, stiffness, limited activity, occasional effusion, and local inflammation. MiR-146 is one of the noncoding RNA closely related to OA, but the role of miR-146 in OA remains controversial. The tumour necrosis factor receptor OX40 is activated by its cognate ligand OX40L (TNFSF4) and functions as a T-cell costimulatory molecule. The T-cell functions, including cytokine production, expansion, and survival, are enhanced by the OX40 costimulatory signals.

METHODS

We established an inflammatory model of condylar chondrocytes induced by IL-1β and TNF-α and detected the expression of miRNA by miRNA sequencing. Then, cell transfection was used to study the role of miR146a-5p in OA. The Kyoto Encyclopedia of Genes and Genomes (KEGG) and database analysis were used to screen out potential target genes of miR-146a-5p. A dual luciferase activity assay tested whether ox40l is the target gene of miR-146a-5p.

RESULTS

MiR-146a-5p and OX40L was upregulated after induced by IL-1β and TNF-α, miR-146a-5p reduced the production of inflammatory factors but had no effect on chondrophenotypic factors, and ox40l was targeted by miR-146a-5p.

CONCLUSION

OX40L and miR-146a-5p of condylar chondrocytes in the inflammatory environment (induced by IL-1β and TNF-α) were significantly increased, miR-146a-5p is a protective factor in the inflammatory response, which can reduce the production of inflammatory factors, and miR-146a-5p may regulate T-cell-mediated immunity through targeting of ox40l in OA.

Antidepressive properties of microglial stimulation in a mouse model of depression induced by chronic unpredictable stress

The decrease of microglia in the hippocampus is a novel mechanism for depression onset. Reversal of this decrease can ameliorate stress-induced depression-like behaviors in rodents. However, the property of this therapeutic strategy remains unclear. We addressed this issue by designing a series of behavioral experiments. Results showed that a single lipopolysaccharide (LPS) injection at the dose of 75 and 100 μg/kg, but not at 30 or 50 μg/kg, produced obvious antidepressant effects in chronic unpredictable stress (CUS) mice at 5 h after the drug administration. In the time-dependent experiment, a single LPS injection (100 μg/kg) ameliorated the CUS-induced depression-like behaviors in mice at 5 and 8 h, but not at 3 h, after the drug administration. The antidepressant effect of a single LPS injection persisted at least 10 days and disappeared at 14 days after the drug administration. 14 days after the first injection, a second LPS injection (100 μg/kg) still produced antidepressant effects in chronically-stressed mice who re-displayed depression-like behaviors at 5 h after the drug administration. The antidepressant effect of LPS appears to be dependent on microglia, as at 5 h after LPS administration (100 μg/kg), the CUS-induced decrease in microglial numbers and Iba-1 mRNA levels in the hippocampus was reversed markedly, and inhibition of microglia by minocycline (40 mg/kg) or PLX33297 (290 mg/kg) prevented the antidepressant effect of LPS in CUS mice. These results indicate that a single LPS injection displays rapid and sustained antidepressant effects in chronically stressed mice likely through stimulating hippocampal microglia.

Effects of ambient ozone exposure on circulating extracellular vehicle microRNA levels in coronary artery disease patients

Exposure to ambient air pollutants such as ozone (O₃) and particulate matter (PM) is associated with increased cardiovascular morbidity and rate of mortality, but the underlying biological mechanisms have yet to be described. Emerging evidence shows that extracellular vehicle (EV) microRNAs (miRNAs) may facilitate cell-to-cell and organ-to-organ communications and play a role in the air pollution-induced cardiovascular effects. This study aims to explore the association between air pollutant exposure and miRNA changes related to cardiovascular diseases. Using a panel study design, 14 participants with coronary artery diseases were enrolled in this study. Each participant had up to 10 clinical visits and their plasma samples were collected and measured for expression of miRNA-21 (miR-21), miR-126, miR-146, miR-150, and miR-155. Mixed effects models adjusted for temperature, humidity, and season were used to examine the association between miRNA levels and exposure to 8-hr O₃ or 24-hr PM_2.5 up to 4 days prior. Results demonstrated that miR-150 expression was positively associated with O₃ exposure at 1-4 days lag and 5day moving average while miR-155 expression tracked with O₃ exposure at lag 0. No significant association was found between miRNA expression and ambient PM_2.5 at any time point. β-blocker and diabetic medication usage significantly modified the correlation between O₃ exposure and miR-150 expression where the link was more prominent among non-users. In conclusion, evidence indicated an association between exposure to ambient O₃ and circulating levels of EV miR-150 and miR-155 was observed. These findings pointed to a future research direction involving miRNA-mediated mechanisms of O₃-induced cardiovascular effects.

Apoptosis-triggered decline in hippocampal microglia mediates adolescent intermittent alcohol exposure-induced depression-like behaviors in mice

Depression-alcohol addiction comorbidity is a common clinical phenomenon. Alcohol exposure in adolescence has been shown to induce depression-like behaviors in rodents. However, the mechanism of action for this type of depression remains unclear. Previous studies have reported that several different types of stress, such as chronic unpredictable stress and early social isolation, trigger depression-like symptoms in mice by inducing hippocampal microglial decline, which is mediated by the initial activation of the microglial cells. Since alcohol also activates microglia, we evaluated the dynamic changes in hippocampal microglia in mice receiving adolescent intermittent alcohol exposure (AIE). Our results showed that 14 days of AIE, followed by 21 days period of no treatment, induced behavioral abnormalities as well as a significant loss and dystrophy of hippocampal microglia in mice. We found that this AIE-induced decline in hippocampal microglia was mediated by both microglial activation and apoptosis, as (i) 1 day of alcohol exposure induced a distinct activation of hippocampal microglia followed by their apoptosis, and (ii) blocking the initial activation of hippocampal microglia by pretreatment with minocycline suppressed the AIE-induced apoptosis and loss of hippocampal microglia as well as the AIE-induced depression-like symptoms. Lipopolysaccharide (LPS), a classical activator of microglia, ameliorated the AIE-induced depression-like symptoms by reversing the decline in the hippocampal microglia. These results reveal a possible mechanism for AIE-induced depression and demonstrate that the restoration of hippocampal microglial homeostasis may be a therapeutic strategy for depression induced by alcohol intake and withdrawal.

Evolutionary dynamics of microRNA target sites across vertebrate evolution

MicroRNAs (miRNAs) control the abundance of the majority of the vertebrate transcriptome. The recognition sequences, or target sites, for bilaterian miRNAs are found predominantly in the 3' untranslated regions (3'UTRs) of mRNAs, and are amongst the most highly conserved motifs within 3'UTRs. However, little is known regarding the evolutionary pressures that lead to loss and gain of such target sites. Here, we quantify the selective pressures that act upon miRNA target sites. Notably, selective pressure extends beyond deeply conserved binding sites to those that have undergone recent substitutions. Our approach reveals that even amongst ancient animal miRNAs, which exert the strongest selective pressures on 3'UTR sequences, there are striking differences in patterns of target site evolution between miRNAs. Considering only ancient animal miRNAs, we find three distinct miRNA groups, each exhibiting characteristic rates of target site gain and loss during mammalian evolution. The first group both loses and gains sites rarely. The second group shows selection only against site loss, with site gains occurring at a neutral rate, whereas the third loses and gains sites at neutral or above expected rates. Furthermore, mutations that alter the strength of existing target sites are disfavored. Applying our approach to individual transcripts reveals variation in the distribution of selective pressure across the transcriptome and between miRNAs, ranging from strong selection acting on a small subset of targets of some miRNAs, to weak selection on many targets for other miRNAs. miR-20 and miR-30, and many other miRNAs, exhibit broad, deeply conserved targeting, while several other comparably ancient miRNAs show a lack of selective constraint, and a small number, including mir-146, exhibit evidence of rapidly evolving target sites. Our approach adds valuable perspective on the evolution of miRNAs and their targets, and can also be applied to characterize other 3'UTR regulatory motifs.

MiR-146a mimic attenuates murine allergic rhinitis by downregulating TLR4/TRAF6/NF-κB pathway

Aim: This study aims to investigate whether microRNA (miR)-146a exerts therapeutic potential to allergic rhinitis (AR). Methods: Female BALB/c mice were randomly divided into the AR and miR-146a groups. miR-146a was administered into the nostril before ovalbumin (OVA) challenge daily on days 21–28. Results: The expression level of miR-146a in AR nasal mucosa was significantly decreased. miR-146a mimic markedly attenuated sneezing and nasal rubbing events, decreased the levels of ovalbumin-specific IgE as well as mastocyte- and basophil-related inflammatory cytokines, reduced inflammatory cells, affected the T-helper 2-released cytokines. Furthermore, miR-146a mimic inhibited the expressions of proteins relevant to Toll-like receptor 4 (TLR4)/TRAF6/NF-κB signaling pathway. Conclusion: The anti-inflammatory effects of miR-146a on AR might exert through the inhibition of the toll-like receptor 4 (TLR4)/TRAF6/NF-κB signaling pathway to some extent.