Interleukin-27 inhibits foam cell formation by promoting macrophage ABCA1 expression through JAK2/STAT3 pathway

An updated advancement of bifunctional IL-27 in inflammatory autoimmune diseases

Interleukin-27 (IL-27) is a member of the IL-12 family. The gene encoding IL-27 is located at chromosome 16p11. IL-27 is considered as a heterodimeric cytokine, which consists of Epstein-Barr virus (EBV)-induced gene 3 (Ebi3) and IL-27p28. Based on the function of IL-27, it binds to receptor IL-27rα or gp130 and then regulates downstream cascade. To date, findings show that the expression of IL-27 is abnormal in different inflammatory autoimmune diseases (including systemic lupus erythematosus, rheumatoid arthritis, Sjogren syndrome, Behcet's disease, inflammatory bowel disease, multiple sclerosis, systemic sclerosis, type 1 diabetes, Vogt-Koyanagi-Harada, and ankylosing spondylitis). Moreover, in vivo and in vitro studies demonstrated that IL-27 is significantly in3volved in the development of these diseases by regulating innate and adaptive immune responses, playing either an anti-inflammatory or a pro-inflammatory role. In this review, we comprehensively summarized information about IL-27 and autoimmunity based on available evidence. It is hoped that targeting IL-27 will hold great promise in the treatment of inflammatory autoimmune disorders in the future.

Rosmarinic Acid Increases Macrophage Cholesterol Efflux through Regulation of ABCA1 and ABCG1 in Different Mechanisms

Lipid dysregulation in diabetes mellitus escalates endothelial dysfunction, the initial event in the development and progression of diabetic atherosclerosis. In addition, lipid-laden macrophage accumulation in the arterial wall plays a significant role in the pathology of diabetes-associated atherosclerosis. Therefore, inhibition of endothelial dysfunction and enhancement of macrophage cholesterol efflux is the important antiatherogenic mechanism. Rosmarinic acid (RA) possesses beneficial properties, including its anti-inflammatory, antioxidant, antidiabetic and cardioprotective effects. We previously reported that RA effectively inhibits diabetic endothelial dysfunction by inhibiting inflammasome activation in endothelial cells. However, its effect on cholesterol efflux remains unknown. Therefore, in this study, we aimed to assess the effect of RA on cholesterol efflux and its underlying mechanisms in macrophages. RA effectively reduced oxLDL-induced cholesterol contents under high glucose (HG) conditions in macrophages. RA enhanced ATP-binding cassette transporter A1 (ABCA1) and G1 (ABCG1) expression, promoting macrophage cholesterol efflux. Mechanistically, RA differentially regulated ABCA1 expression through JAK2/STAT3, JNK and PKC-p38 and ABCG1 expression through JAK2/STAT3, JNK and PKC-ERK1/2/p38 in macrophages. Moreover, RA primarily stabilized ABCA1 rather than ABCG1 protein levels by impairing protein degradation. These findings suggest RA as a candidate therapeutic to prevent atherosclerotic cardiovascular disease complications related to diabetes by regulating cholesterol efflux in macrophages.

The Role of Interleukin-27 in Atherosclerosis: A Contemporary Review

Atherosclerosis is a chronic inflammation characterized by an imbalance between inhibitors and stimulators of the inflammatory system that leads to the formation of atherosclerotic plaques in the vessel walls. Interleukin (IL)-27 is one of the recently discovered cytokines that have an immunomodulatory role in autoimmune and inflammatory diseases. However, the definite role of IL-27 in the pathogenesis of atherosclerosis remains unclear. Recent studies on cardiomyocytes and vascular endothelium have demonstrated mechanisms through which IL-27 could potentially modulate atherosclerosis. Upregulation of the IL-27 receptor was also observed in the atherosclerotic plaques. In addition, circulatory IL-27 levels were increased in patients with acute coronary syndrome and myocardial infarction. A regenerative, neovascularization, and cardioprotective role of IL-27 has also been implicated. Future studies are warranted to elucidate the biologic function and clinical significance of IL-27 in atherosclerosis.

The Endothelium as a Target for Anti-Atherogenic Therapy: A Focus on the Epigenetic Enzymes EZH2 and SIRT1

Endothelial cell inflammatory activation and dysfunction are key events in the pathophysiology of atherosclerosis, and are associated with an elevated risk of cardiovascular events. Yet, therapies specifically targeting the endothelium and atherosclerosis are lacking. Here, we review how endothelial behaviour affects atherogenesis and pose that the endothelium may be an efficacious cellular target for antiatherogenic therapies. We discuss the contribution of endothelial inflammatory activation and dysfunction to atherogenesis and postulate that the dysregulation of specific epigenetic enzymes, EZH2 and SIRT1, aggravate endothelial dysfunction in a pleiotropic fashion. Moreover, we propose that commercially available drugs are available to clinically explore this postulation.

CD63 negatively regulates hepatocellular carcinoma development through suppression of inflammatory cytokine-induced STAT3 activation

Tetraspanin CD63 has been widely implicated in tumour progression of human malignancies. However, its role in the tumorigenesis and metastasis of hepatocellular carcinoma (HCC) remains unclear yet. In the present study, we aimed to investigate the specific function and underlying mechanisms of CD63 in HCC progression. CD63 expression in HCC tissues was detected using immunohistochemistry and quantitative real-time PCR analyses; effects of CD63 on HCC cell proliferation and migration were investigated by CCK-8 assay, colony formation assay, transwell assay and a xenograft model of nude mice. RNA-sequencing, bioinformatics analysis, dual-luciferase reporter assay and Western blot analysis were performed to explore the underlying molecular mechanisms. Results of our experiments showed that CD63 expression was frequently reduced in HCC tissues compared with adjacent normal tissues, and decreased CD63 expression was significantly associated with larger tumour size, distant site metastasis and higher tumour stages of HCC. Overexpression of CD63 inhibited HCC cell proliferation and migration, whereas knockdown of CD63 promoted these phenotypes. IL-6, IL-27 and STAT3 activity was regulated by CD63, and blockade of STAT3 activation impaired the promotive effects of CD63 knockdown on HCC cell growth and migration. Our findings identified a novel CD63-IL-6/IL-27-STAT3 axis in the development of HCC and provided a potential target for the diagnosis and treatment of this disease.

Regulation of ATP binding cassette transporter A1 (ABCA1) expression: cholesterol-dependent and - independent signaling pathways with relevance to inflammatory lung disease

The role of the ATP binding cassette transporter A1 (ABCA1) in maintaining cellular lipid homeostasis in cardiovascular disease is well established. More recently, the important beneficial role played by ABCA1 in modulating pathogenic disease mechanisms, such as inflammation, in a broad range of chronic conditions has been realised. These studies position ABCA1 as a potential therapeutic target in a diverse range of diseases where inflammation is an underlying cause. Chronic respiratory conditions such as asthma and chronic obstructive pulmonary disease (COPD) are driven by inflammation, and as such, there is now a growing recognition that we need a greater understanding of the signaling pathways responsible for regulation of ABCA1 expression in this clinical context. While the signaling pathways responsible for cholesterol-mediated ABCA1 expression have been clearly delineated through decades of studies in the atherosclerosis field, and thus far appear to be translatable to the respiratory field, less is known about the cholesterol-independent signaling pathways that can modulate ABCA1 expression in inflammatory lung disease. This review will identify the various signaling pathways and ligands that are associated with the regulation of ABCA1 expression and may be exploited in future as therapeutic targets in the setting of chronic inflammatory lung diseases.

Interleukin-5 promotes ATP-binding cassette transporter A1 expression through miR-211/JAK2/STAT3 pathways in THP-1-dervied macrophages

Interleukin-5 (IL-5) is manifested as its involvement in the process of atherosclerosis, but the mechanism is still unknown. In this study, we explored the effect of IL-5 on lipid metabolism and its underlying mechanisms in THP-1-derived macrophages. The quantitative polymerase chain reaction (qPCR) and western blot analysis results showed that IL-5 significantly up-regulated ATP-binding cassette transporter A1 (ABCA1) expression in a dose-dependent and time-dependent manner. [3H]-labeled cholesterol was used to assess the levels of cholesterol efflux, and the results showed that IL-5 increased ABCA1-mediated cholesterol efflux. A high-performance liquid chromatography assay indicated that cellular cholesterol content was decreased by IL-5 treatment in THP-1-derived macrophages. The selective inhibitor and small interfering RNA were used to block the Janus kinase (JAK)/signal transducer and activator of transcription 3 (STAT3) pathway. The results of the qPCR and western blot analysis showed that IL-5 activated JAK2/STAT3 pathway to up-regulate ABCA1 expression. Meanwhile, IL-5 reduced the expression level of miR-211. Furthermore, we found that JAK2 is a target gene of miR-211 and miR-211 mimic inhibited the expression of JAK2 and reduced the levels of p-STAT3 and ABCA1 as revealed by luciferase reporter assay, qPCR and western blot analysis. In summary, these findings indicated that IL-5 promotes ABCA1 expression and cholesterol efflux through the miR-211/JAK2/STAT3 signaling pathway in THP-1-derived macrophages.

Analysis of Low Molecular Weight Substances and Related Processes Influencing Cellular Cholesterol Efflux

Cholesterol efflux is the key process protecting the vascular system from the development of atherosclerotic lesions. Various extracellular and intracellular events affect the ability of the cell to efflux excess cholesterol. To explore the possible pathways and processes that promote or inhibit cholesterol efflux, we applied a combined cheminformatic and bioinformatic approach. We performed a comprehensive analysis of published data on the various substances influencing cholesterol efflux and found 153 low molecular weight substances that are included in the Chemical Entities of Biological Interest (ChEBI) database. Pathway enrichment was performed for substances identified within the Reactome database, and 45 substances were selected in 93 significant pathways. The most common pathways included the energy-dependent processes related to active cholesterol transport from the cell, lipoprotein metabolism and lipid transport, and signaling pathways. The activators and inhibitors of cholesterol efflux were non-uniformly distributed among the different pathways: the substances influencing ‘biological oxidations’ activate cholesterol efflux and the substances influencing ‘Signaling by GPCR and PTK6’ inhibit efflux. This analysis may be used in the search and design of efflux effectors for therapies targeting structural and functional high-density lipoprotein deficiency.

Predicting dyslipidemia after liver transplantation: A significant role of recipient metabolic inflammation profile

BACKGROUND

Post-transplant dyslipidemia (PTDL) is a common complication in liver recipients and can cause morbidity and threaten graft function. The crosstalk between metabolic inflammation and dyslipidemia has been recently revealed. However, the role of grafts’ and recipients’ metabolic status in the development of PTDL has not been evaluated.

AIM

To investigate the association of recipients’ metabolic inflammation status with PTDL and construct a predictive model.

METHODS

A total of 396 adult patients who received primary liver transplantation between 2015 and 2017 were enrolled. Metabolomics and cytokines were analyzed using recipients’ pre-transplant peripheral blood in a training set (n = 72). An integrated prediction model was established according to the clinical risk factors and metabolic inflammation compounds and further verified in a validation set (n = 144).

RESULTS

The serum lipid profile took 3 mo to reach homeostasis after liver transplantation. A total of 278 (70.2%) liver recipients developed PTDL during a follow-up period of 1.78 (1.00, 2.97) years. The PTDL group showed a significantly lower tumor-free survival and overall survival than the non-PTDL group in patients with hepatocellular carcinoma (n = 169). The metabolomic analysis showed that metabolic features discriminating between the PTDL and non-PTDL groups were associated with lipid and glucose metabolism-associated pathways. Among metabolites and cytokines differentially expressed between the two groups, interleukin-12 (p70) showed the best diagnostic accuracy and significantly increased the predictive value when it was incorporated into the clinical model in both training and validation sets.

CONCLUSION

Recipients’ pre-transplant serum interleukin-12 (p70) level is associated with the risk of PTDL and has potential clinical value for predicting PTDL.

Interleukin-27 decreases ghrelin production through signal transducer and activator of transcription 3-mechanistic target of rapamycin signaling

Interleukin-27 (IL-27), a heterodimeric cytokine, plays a protective role in diabetes. Ghrelin, a gastric hormone, provides a hunger signal to the central nervous system to stimulate food intake. The relationship between IL-27 and ghrelin is still unexplored. Here we investigated that signal transducer and activator of transcription 3 (STAT3)—mechanistic target of rapamycin (mTOR) signaling mediates the suppression of ghrelin induced by IL-27. Co-localization of interleukin 27 receptor subunit alpha (WSX-1) and ghrelin was observed in mouse and human gastric mucosa. Intracerebroventricular injection of IL-27 markedly suppressed ghrelin synthesis and secretion while stimulating STAT3–mTOR signaling in both C57BL/6J mice and high-fat diet-induced-obese mice. IL-27 inhibited the production of ghrelin in mHypoE-N42 cells. Inhibition of mTOR activity induced by mTOR siRNA or rapamycin blocked the suppression of ghrelin production induced by IL-27 in mHypoE-N42 cells. Stat 3 siRNA also abolished the inhibitory effect of IL-27 on ghrelin. IL-27 increased the interaction between STAT3 and mTOR in mHypoE-N42 cells. In conclusion, IL-27 suppresses ghrelin production through the STAT3-mTOR dependent mechanism.

Interferon-stimulated gene 15 promotes cholesterol efflux by activating autophagy via the miR-17-5p/Beclin-1 pathway in THP-1 macrophage-derived foam cells

Macrophage autophagy contributes to the hydrolysis of cholesteryl ester into free cholesterol mainly for ATP-binding cassette transporter A1 (ABCA1)-dependent efflux. Interferon-stimulated gene 15 (ISG15) has been shown to regulate autophagy in multiple types of cells. The present study aimed to examine the effects of ISG15 on autophagy and cholesterol efflux in THP-1 macrophage-derived foam cells and to explore the underlying molecular mechanisms. Our results showed that overexpression of ISG15 promoted autophagy and cholesterol efflux and inhibited lipid accumulation without impact on ABCA1 expression. Inhibition of autophagy by 3-methyladenine (3-MA) abrogated the enhancing effects of ISG15 on cholesterol efflux. Both bioinformatics analysis and dual luciferase reporter assay identified Beclin-1 as a direct target of miR-17-5p. Moreover, ISG15 overexpression markedly decreased miR-17-5p levels and upregulated Beclin-1 expression. ISG15-induced enhancement of autophagy and cholesterol efflux was reversed by pretreatment with either miR-17-5p mimic or Beclin-1 siRNA. In conclusion, these findings suggest that ISG15 reduces miR-17-5p levels and thereby promotes Beclin-1-mediated autophagy, resulting in increased cholesterol efflux from THP-1 macrophage-derived foam cells.

An inhibitor of cholesterol absorption displays anti-myeloma activity by targeting the JAK2-STAT3 signaling pathway

The activated JAK2-STAT3 signaling pathway is a high risk factor for multiple myeloma (MM), a fatal malignancy of plasma cells. In the present study, SC09, a potential inhibitor of cholesterol absorption, was identified in a STAT3-targeted drug screen. SC09 suppressed the activation of STAT3 in a time-course and concentration-dependent manner but did not affect its family members STAT1 and STAT5. SC09 inhibited STAT3 transcriptional activity and downregulated the expression of STAT3-regulated genes. Further studies showed that SC09 selectively inhibited JAK2 activation but not other kinases including c-Src, ERK, p38 and mTOR that are all associated with STAT3 activation. Moreover, SC09 obviously induced MM cell death in vitro and delayed MM tumor growth in vivo. SC09-induced MM cell death was dependent on the endogenous STAT3 status, and this effect could be attenuated by enforced expression of STAT3. All the results collectively indicated that SC09 blocks the JAK2-STAT3 signaling thus displaying anti-MM activity. Given its well tolerance and anti-MM potency, SC09 is credited for further investigation as a promising drug for MM treatment.

Interleukin 27 is increased in carotid atherosclerosis and promotes NLRP3 inflammasome activation

Aim

Interleukin-27 (IL-27) is involved in different inflammatory diseases; however, its role in atherosclerosis is unclear. In this study we investigated the expression of IL-27 and its receptor in patients with carotid atherosclerosis and if IL-27 could modulate the inflammatory effects of the NLRP3 inflammasome in vitro.

Methods

Plasma IL-27 was measured by enzyme immunoassay in patients with carotid stenosis (n = 140) and in healthy controls (n = 19). Expression of IL-27 and IL-27R was analyzed by quantitative PCR and immunohistochemistry in plaques from patients and in non-atherosclerotic vessels. THP-1 monocytes, primary monocytes and peripheral blood mononuclear cells (PBMCs) were used to study effects of IL-27 in vitro.

Results

Our main findings were: (i) Plasma levels of IL-27 were significantly elevated in patients with carotid atherosclerotic disease compared to healthy controls. (ii) Gene expression of IL-27 and IL-27R was significantly elevated in plaques compared to control vessels, and co-localized to macrophages. (iii) In vitro, IL-27 increased NLRP3 inflammasome activation in monocytes with enhanced release of IL-1 β.

Conclusions

We demonstrate increased levels of IL-27 and IL-27R in patients with carotid atherosclerosis. Our in vitro findings suggest an inflammatory role for IL-27, which can possibly be linked to atherosclerotic disease development.

Interleukin-22 Might Act as a Double-Edged Sword in Type 2 Diabetes and Coronary Artery Disease

Type 2 diabetes mellitus (T2DM) and coronary artery disease (CAD) are both characterized by chronic low-grade inflammation. The role of Th17 and its related cytokines in T2DM and CAD is unclear. Here we investigated the serum levels of five Th17-related cytokines (IL-17, IL-22, MIP-3α, IL-9, and IL-27) in T2DM, CAD, and T2DM-CAD comorbidity patients. IL-22 was found to be elevated in all three conditions. Elevated serum IL-22 was independently associated with the incidence of T2DM and CAD. Conversely, IL-22 was found to protect endothelial cells from glucose- and lysophosphatidylcholine- (LPC-) induced injury, and IL-22R1 expression on endothelial cells was increased upon treatment with high glucose and LPC. Blocking of IL-22R1 with IL-22R1 antibody diminished the protective role of IL-22. Our results suggest that IL-22 functions as a double-edged sword in T2DM and CAD and that IL-22 may be used in the treatment of chronic inflammatory diseases such as T2DM and CAD.

Effects of cigarette smoking on cardiovascular-related protein profiles in two community-based cohort studies

BACKGROUND AND AIMS

Cardiovascular diseases account for the largest fraction of smoking-induced deaths. Studies of smoking in relation to cardiovascular-related protein markers can provide novel insights into the biological effects of smoking. We investigated the associations between cigarette smoking and 80 protein markers known to be related to cardiovascular diseases in two community-based cohorts, the Prospective Study of the Vasculature in Uppsala Seniors (PIVUS, n = 969, 50% women, all aged 70 years) and the Uppsala Longitudinal Study of Adult Men (ULSAM, n = 717, all men aged 77 years).

METHODS

Smoking status was self-reported and defined as current smoker, former smoker or never-smoker. Levels of the 80 proteins were measured using the proximity extension assay, a novel PCR-based proteomics technique.

RESULTS

We found 30 proteins to be significantly associated with current cigarette smoking in PIVUS (FDR<5%); and ten were replicated in ULSAM (p < 0.05). Matrix metalloproteinase-12 (MMP-12), growth/differentiation factor 15 (GDF-15), urokinase plasminogen activator surface receptor (uPAR), TNF-related apoptosis-inducing ligand receptor 2 (TRAIL-R2), lectin-like oxidized LDL receptor 1 (LOX-1), hepatocyte growth factor (HGF), matrix metalloproteinase-10 (MMP-10) and matrix metalloproteinase-1 (MMP-1) were positively associated, while endothelial cell-specific molecule 1 (ESM-1) and interleukin-27 subunit alpha (IL27-A) showed inverse associations. All of them remained significant in a subset of individuals without manifest cardiovascular disease.

CONCLUSIONS

The findings of the present study suggest that cigarette smoking may interfere with several essential parts of the atherosclerosis process, as evidenced by associations with protein markers representing endothelial dysfunction, inflammation, neointimal formation, foam cell formation and plaque instability.

Macrophage-activating lipopeptide-2 downregulates the expression of ATP-binding cassette transporter A1 by activating the TLR2/NF-кB/ZNF202 pathway in THP-1 macrophages

Macrophage-activating lipopeptide-2 (MALP-2) has been shown to promote the development of atherosclerosis. ATP-binding cassette transporter A1 (ABCA1), a transmembrane protein, plays a critical role in mediating cholesterol export from macrophages to apolipoprotein A-I (apoA-I). However, whether MALP-2 can regulate the expression of ABCA1 is still largely unknown. The aim of this study was to explore the effects of MALP-2 on ABCA1 expression in THP-1 macrophages and the underlying mechanisms. Our results showed that the treatment of cells with MALP-2 decreased ABCA1 level and suppressed cholesterol efflux in both concentration- and time-dependent manners. The contents of intracellular cholesterol were significantly increased in the presence of MALP-2. Moreover, MALP-2-mediated inhibition of ABCA1 expression was abolished by siRNA of either Toll-like receptor 2 (TLR2) or nuclear factor κB (NF-κB). A similar effect was produced by treatment with the NF-κB inhibitor pyrrolidine dithiocarbamate. In addition, MALP-2-induced activation of NF-κB markedly increased zinc finger protein 202 (ZNF202) level, and ZNF202 siRNA impaired the effects of MALP-2 on ABCA1 expression. Taken together, these results suggest that MALP-2 can decrease ABCA1 expression and subsequent cholesterol efflux through activation of the TLR2/NF-κB/ZNF202 signaling pathway in THP-1 macrophages.

Soluble CD40 ligand promotes macrophage foam cell formation in the etiology of atherosclerosis

OBJECTIVE

High levels of soluble CD40 ligand (sCD40L) in the circulation have been suggested as an important indicator of cardiovascular diseases such as atherosclerosis and acute coronary syndromes. In the present study, we explored the role of sCD40L in the formation of foam cells.

METHODS

Lipid deposition and foam cell formation was measured by high-performance liquid chromatography and Nile Red staining, respectively. Gene expressions were detected by quantitative real-time PCR and Western blot analysis. The interaction between CD40 and sCD40L were blocked by CD40 small interfering RNA or anti-CD40 antibody.

RESULTS

sCD40L significantly increased lipid deposition and foam cell formation associated with upregulation of scavenger receptor type A and CD36. Additionally, sCD40L increased adipocyte enhancer-binding protein 1 and cholesterol efflux, and activated NF-κB in macrophages. sCD40L promoted foam cell formation via CD40 ligation and disruption of the ligation between CD40 and CD40L either by small interfering RNA or by a blocking anti-CD40 antibody apparently inhibiting foam cell formation in response to sCD40L.

CONCLUSION

Our data suggests a novel insight into the role of sCD40L in foam cell formation during atherosclerosis, which further confirms the importance of sCD40L in atherosclerosis and as a target for the treatment of this disease.

Macrophage Heterogeneity and Plasticity: Impact of Macrophage Biomarkers on Atherosclerosis

Cardiovascular disease (CVD) is a global epidemic, currently representing the worldwide leading cause of morbidity and mortality. Atherosclerosis is the fundamental pathophysiologic component of CVD, where the immune system plays an essential role. Monocytes and macrophages are key mediators in this aspect: due to their heterogeneity and plasticity, these cells may act as either pro- or anti-inflammatory mediators. Indeed, monocytes may develop heterogeneous functional phenotypes depending on the predominating pro- or anti-inflammatory microenvironment within the lesion, resulting in classic, intermediate, and non-classic monocytes, each with strikingly differing features. Similarly, macrophages may also adopt heterogeneous profiles being mainly M1 and M2, the former showing a proinflammatory profile while the latter demonstrates anti-inflammatory traits; they are further subdivided in several subtypes with more specialized functions. Furthermore, macrophages may display plasticity by dynamically shifting between phenotypes in response to specific signals. Each of these distinct cell profiles is associated with diverse biomarkers which may be exploited for therapeutic intervention, including IL-10, IL-13, PPAR-γ, LXR, NLRP3 inflammasomes, and microRNAs. Direct modulation of the molecular pathways concerning these potential macrophage-related targets represents a promising field for new therapeutic alternatives in atherosclerosis and CVD.