HDL in Immune-Inflammatory Responses: Implications beyond Cardiovascular Diseases

High density lipoproteins (HDL) are heterogeneous particles composed by a vast array of proteins and lipids, mostly recognized for their cardiovascular (CV) protective effects. However, evidences from basic to clinical research have contributed to depict a role of HDL in the modulation of immune-inflammatory response thus paving the road to investigate their involvement in other diseases beyond those related to the CV system. HDL-C levels and HDL composition are indeed altered in patients with autoimmune diseases and usually associated to disease severity. At molecular levels, HDL have been shown to modulate the anti-inflammatory potential of endothelial cells and, by controlling the amount of cellular cholesterol, to interfere with the signaling through plasma membrane lipid rafts in immune cells. These findings, coupled to observations acquired from subjects carrying mutations in genes related to HDL system, have helped to elucidate the contribution of HDL beyond cholesterol efflux thus posing HDL-based therapies as a compelling interventional approach to limit the inflammatory burden of immune-inflammatory diseases.

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Succinate Is an Inflammation-Induced Immunoregulatory Metabolite in Macrophages

Metabolites ◽

10.3390/metabo10090372 ◽

2020 ◽

Vol 10 (9) ◽

pp. 372 ◽

Cited By ~ 2

Author(s):

Karl J. Harber ◽

Kyra E. de Goede ◽

Sanne G. S. Verberk ◽

Elisa Meinster ◽

Helga E. de Vries ◽

...

Keyword(s):

Immune Responses ◽

Immune Cells ◽

Immune Cell ◽

Inflammatory Responses ◽

Inflammatory Diseases ◽

Cell Phenotype ◽

Independent Manner ◽

Inflammatory Macrophages ◽

Necrosis Factor

Immunometabolism revealed the crucial role of cellular metabolism in controlling immune cell phenotype and functions. Macrophages, key immune cells that support progression of numerous inflammatory diseases, have been well described as undergoing vast metabolic rewiring upon activation. The immunometabolite succinate particularly gained a lot of attention and emerged as a crucial regulator of macrophage responses and inflammation. Succinate was originally described as a metabolite that supports inflammation via distinct routes. Recently, studies have indicated that succinate and its receptor SUCNR1 can suppress immune responses as well. These apparent contradictory effects might be due to specific experimental settings and particularly the use of distinct succinate forms. We therefore compared the phenotypic and functional effects of distinct succinate forms and receptor mouse models that were previously used for studying succinate immunomodulation. Here, we show that succinate can suppress secretion of inflammatory mediators IL-6, tumor necrosis factor (TNF) and nitric oxide (NO), as well as inhibit Il1b mRNA expression of inflammatory macrophages in a SUCNR1-independent manner. We also observed that macrophage SUCNR1 deficiency led to an enhanced inflammatory response without addition of exogenous succinate. While our study does not reveal new mechanistic insights into how succinate elicits different inflammatory responses, it does indicate that the inflammatory effects of succinate and its receptor SUCNR1 in macrophages are clearly context dependent.

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Niacin protects against abdominal aortic aneurysm formation via GPR109A independent mechanisms: role of NAD+/nicotinamide

Cardiovascular Research ◽

10.1093/cvr/cvz303 ◽

2019 ◽

Vol 116 (14) ◽

pp. 2226-2238 ◽

Cited By ~ 5

Author(s):

Tetsuo Horimatsu ◽

Andra L Blomkalns ◽

Mourad Ogbi ◽

Mary Moses ◽

David Kim ◽

...

Keyword(s):

Immune Cells ◽

Inflammatory Cell ◽

Immune Cell ◽

Inflammatory Responses ◽

Aortic Aneurysms ◽

Cell Infiltration ◽

Protective Effects ◽

Abdominal Aortic ◽

G Protein Coupled

Abstract Aims Chronic adventitial and medial infiltration of immune cells play an important role in the pathogenesis of abdominal aortic aneurysms (AAAs). Nicotinic acid (niacin) was shown to inhibit atherosclerosis by activating the anti-inflammatory G protein-coupled receptor GPR109A [also known as hydroxycarboxylic acid receptor 2 (HCA2)] expressed on immune cells, blunting immune activation and adventitial inflammatory cell infiltration. Here, we investigated the role of niacin and GPR109A in regulating AAA formation. Methods and results Mice were supplemented with niacin or nicotinamide, and AAA was induced by angiotensin II (AngII) infusion or calcium chloride (CaCl2) application. Niacin markedly reduced AAA formation in both AngII and CaCl2 models, diminishing adventitial immune cell infiltration, concomitant inflammatory responses, and matrix degradation. Unexpectedly, GPR109A gene deletion did not abrogate the protective effects of niacin against AAA formation, suggesting GPR109A-independent mechanisms. Interestingly, nicotinamide, which does not activate GPR109A, also inhibited AAA formation and phenocopied the effects of niacin. Mechanistically, both niacin and nicotinamide supplementation increased nicotinamide adenine dinucleotide (NAD+) levels and NAD+-dependent Sirt1 activity, which were reduced in AAA tissues. Furthermore, pharmacological inhibition of Sirt1 abrogated the protective effect of nicotinamide against AAA formation. Conclusion Niacin protects against AAA formation independent of GPR109A, most likely by serving as an NAD+ precursor. Supplementation of NAD+ using nicotinamide-related biomolecules may represent an effective and well-tolerated approach to preventing or treating AAA.

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Role of MIF in myocardial ischaemia and infarction: insight from recent clinical and experimental findings

Clinical Science ◽

10.1042/cs20130828 ◽

2014 ◽

Vol 127 (3) ◽

pp. 149-161 ◽

Cited By ~ 31

Author(s):

Nalin H. Dayawansa ◽

Xiao-Ming Gao ◽

David A. White ◽

Anthony M. Dart ◽

Xiao-Jun Du

Keyword(s):

Myocardial Ischaemia ◽

Immune Cells ◽

Inflammatory Responses ◽

Inflammatory Diseases ◽

Metabolic Activation ◽

Infarct Healing ◽

Acute Mi ◽

Antioxidative Stress ◽

Experimental Findings

First discovered in 1966 as an inflammatory cytokine, MIF (macrophage migration inhibitory factor) has been extensively studied for its pivotal role in a variety of inflammatory diseases, including rheumatoid arthritis and atherosclerosis. Although initial studies over a decade ago reported increases in circulating MIF levels following acute MI (myocardial infarction), the dynamic changes in MIF and its pathophysiological significance following MI have been unknown until recently. In the present review, we summarize recent experimental and clinical studies examining the diverse functions of MIF across the spectrum of acute MI from brief ischaemia to post-infarct healing. Following an acute ischaemic insult, MIF is rapidly released from jeopardized cardiomyocytes, followed by a persistent MIF production and release from activated immune cells, resulting in a sustained increase in circulating levels of MIF. Recent studies have documented two distinct actions of MIF following acute MI. In the supra-acute phase of ischaemia, MIF mediates cardioprotection via several distinct mechanisms, including metabolic activation, apoptosis suppression and antioxidative stress. In prolonged myocardial ischaemia, however, MIF promotes inflammatory responses with largely detrimental effects on cardiac function and remodelling. The pro-inflammatory properties of MIF are complex and involve MIF derived from cardiac and immune cells contributing sequentially to the innate immune response evoked by MI. Emerging evidence on the role of MIF in myocardial ischaemia and infarction highlights a significant potential for the clinical use of MIF agonists or antagonists and as a unique cardiac biomarker.

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The Mannose Receptor: From Endocytic Receptor and Biomarker to Regulator of (Meta)Inflammation

Frontiers in Immunology ◽

10.3389/fimmu.2021.765034 ◽

2021 ◽

Vol 12 ◽

Author(s):

Hendrik J. P. van der Zande ◽

Dominik Nitsche ◽

Laura Schlautmann ◽

Bruno Guigas ◽

Sven Burgdorf

Keyword(s):

Immune Cells ◽

Antigen Processing ◽

Inflammatory Responses ◽

Inflammatory Diseases ◽

Mannose Receptor ◽

Soluble Form ◽

Activated T Cells ◽

Antigen Presenting ◽

Antigen Processing And Presentation

The mannose receptor is a member of the C-type lectin (CLEC) family, which can bind and internalize a variety of endogenous and pathogen-associated ligands. Because of these properties, its role in endocytosis as well as antigen processing and presentation has been studied intensively. Recently, it became clear that the mannose receptor can directly influence the activation of various immune cells. Cell-bound mannose receptor expressed by antigen-presenting cells was indeed shown to drive activated T cells towards a tolerogenic phenotype. On the other hand, serum concentrations of a soluble form of the mannose receptor have been reported to be increased in patients suffering from a variety of inflammatory diseases and to correlate with severity of disease. Interestingly, we recently demonstrated that the soluble mannose receptor directly promotes macrophage proinflammatory activation and trigger metaflammation. In this review, we highlight the role of the mannose receptor and other CLECs in regulating the activation of immune cells and in shaping inflammatory responses.

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The Immunomodulatory Role of G2013 (α-L-Guluronic Acid) on the Expression of TLR2 and TLR4 in HT29 cell line

Current Drug Discovery Technologies ◽

10.2174/1570163815666180226093711 ◽

2019 ◽

Vol 16 (1) ◽

pp. 91-95 ◽

Cited By ~ 4

Author(s):

Hamid Farhang ◽

Laleh Sharifi ◽

Mohammad Mehdi Soltan Dallal ◽

Mona Moshiri ◽

Zahra Norouzbabaie ◽

...

Keyword(s):

Inflammatory Responses ◽

Inflammatory Diseases ◽

Rna Extraction ◽

Cell Plate ◽

Inhibitory Effect ◽

Control Group ◽

Ht29 Cells ◽

Guluronic Acid ◽

Tlr4 Mrna

Background: The non-steroidal anti-inflammatory drugs (NSAIDs) play crucial role in the controlling of inflammatory diseases. Due to the vast side effects of NSAIDs, its use is limited. G2013 or &#945;-L-Guluronic Acid is a new NSAID with immunomodulatory features. Objectives: Considering the leading role of TLRs in inflammatory responses, in this study, we aimed to evaluate G2013 cytotoxicity and its effect on the expression of TLR2 and TLR4 molecules. Methods: HEK293-TLR2 and HEK293-TLR4 cells were cultured and seeded on 96-well cell plate, and MTT assay was performed for detecting the viability of the cells after treatment with different concentrations of G2013. HT29 cells were grown and treated with low and high doses of G2013. After total RNA extraction and cDNA synthesis, quantitative real-time PCR were performed to assess the TLR2 and TLR4 mRNA synthesis. Results: We found that concentrations of ≤125 &#181;g/ml of G2013 had no apparent cytotoxicity effect on the HEK293-TLR2 and -TLR4 cells. Our results indicated that after G2013 treatment (5 &#181;g/ml) in HT29 cells, TLR2 and TLR4 mRNA expression decreased significantly compared with the untreated control group (p=0.02 and p=0.001 respectively). Conclusion: The results of this study revealed that G2013 can down regulate the TLR2 and TLR4 gene expression and exerts its inhibitory effect. Our findings are parallel to our previous finding which showed G2013 ability to down regulate the signaling pathway of TLRs. However, further studies are needed to identify the molecular mechanism of G2013.<p>

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The Role of Src Kinase in Macrophage-Mediated Inflammatory Responses

Mediators of Inflammation ◽

10.1155/2012/512926 ◽

2012 ◽

Vol 2012 ◽

pp. 1-18 ◽

Cited By ~ 115

Author(s):

Se Eun Byeon ◽

Young-Su Yi ◽

Jueun Oh ◽

Byong Chul Yoo ◽

Sungyoul Hong ◽

...

Keyword(s):

Rheumatoid Arthritis ◽

Immune Responses ◽

Inflammatory Responses ◽

Inflammatory Diseases ◽

Src Kinase ◽

Multiple Roles ◽

Cellular Migration ◽

Pharmaceutical Drugs ◽

Tyrosine Protein Kinase

Src kinase (Src) is a tyrosine protein kinase that regulates cellular metabolism, survival, and proliferation. Many studies have shown that Src plays multiple roles in macrophage-mediated innate immunity, such as phagocytosis, the production of inflammatory cytokines/mediators, and the induction of cellular migration, which strongly implies that Src plays a pivotal role in the functional activation of macrophages. Macrophages are involved in a variety of immune responses and in inflammatory diseases including rheumatoid arthritis, atherosclerosis, diabetes, obesity, cancer, and osteoporosis. Previous studies have suggested roles for Src in macrophage-mediated inflammatory responses; however, recently, new functions for Src have been reported, implying that Src functions in macrophage-mediated inflammatory responses that have not been described. In this paper, we discuss recent studies regarding a number of these newly defined functions of Src in macrophage-mediated inflammatory responses. Moreover, we discuss the feasibility of Src as a target for the development of new pharmaceutical drugs to treat macrophage-mediated inflammatory diseases. We provide insights into recent reports regarding new functions for Src that are related to macrophage-related inflammatory responses and the development of novel Src inhibitors with strong immunosuppressive and anti-inflammatory properties, which could be applied to various macrophage-mediated inflammatory diseases.

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Protective Features of Autophagy in Pulmonary Infection and Inflammatory Diseases

Cells ◽

10.3390/cells8020123 ◽

2019 ◽

Vol 8 (2) ◽

pp. 123 ◽

Cited By ~ 12

Author(s):

Kui Wang ◽

Yi Chen ◽

Pengju Zhang ◽

Ping Lin ◽

Na Xie ◽

...

Keyword(s):

Pulmonary Infection ◽

Inflammatory Responses ◽

Inflammatory Diseases ◽

Chronic Obstructive ◽

Obstructive Pulmonary Disease ◽

Autophagy Pathway ◽

Pulmonary Arterial ◽

Cellular Components ◽

Cellular Stressors

Autophagy is a highly conserved catabolic process involving autolysosomal degradation of cellular components, including protein aggregates, damaged organelles (such as mitochondria, endoplasmic reticulum, and others), as well as various pathogens. Thus, the autophagy pathway represents a major adaptive response for the maintenance of cellular and tissue homeostasis in response to numerous cellular stressors. A growing body of evidence suggests that autophagy is closely associated with diverse human diseases. Specifically, acute lung injury (ALI) and inflammatory responses caused by bacterial infection or xenobiotic inhalation (e.g., chlorine and cigarette smoke) have been reported to involve a spectrum of alterations in autophagy phenotypes. The role of autophagy in pulmonary infection and inflammatory diseases could be protective or harmful dependent on the conditions. In this review, we describe recent advances regarding the protective features of autophagy in pulmonary diseases, with a focus on ALI, idiopathic pulmonary fibrosis (IPF), chronic obstructive pulmonary disease (COPD), tuberculosis, pulmonary arterial hypertension (PAH) and cystic fibrosis.

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Inhibitory Effects of the Two Novel TSPO Ligands 2-Cl-MGV-1 and MGV-1 on LPS-induced Microglial Activation

Cells ◽

10.3390/cells8050486 ◽

2019 ◽

Vol 8 (5) ◽

pp. 486 ◽

Cited By ~ 7

Author(s):

Sheelu Monga ◽

Rafi Nagler ◽

Rula Amara ◽

Abraham Weizman ◽

Moshe Gavish

Keyword(s):

Inflammatory Responses ◽

Inflammatory Diseases ◽

Cell Metabolism ◽

Interferon Γ ◽

Translocator Protein ◽

Ros Generation ◽

Protective Effects ◽

Neuronal Progenitor ◽

Cytokines And Chemokines ◽

Factor Α

The 18 kDa translocator protein (TSPO) ligands 2-Cl-MGV-1 and MGV-1 can attenuate cell death of astrocyte-like cells (U118MG) and induce differentiation of neuronal progenitor cells (PC-12). Lipopolysaccharide (LPS) is a bacterial membrane endotoxin that activates cellular inflammatory pathways by releasing pro-inflammatory molecules, including cytokines and chemokines. The aim of the present study was to assess the immuno-modulatory effect of TSPO ligands in activated microglial cells. We demonstrated that the TSPO ligands 2-Cl-MGV-1 and MGV-1 can prevent LPS-induced activation of microglia (BV-2 cell line). Co-treatment of LPS (100 ng/mL) with these TSPO ligands (final concentration- 25 µM) reduces significantly the LPS-induced release of interleukin-6 (IL-6) from 16.9-fold to 2.5-fold, IL-β from 8.3-fold to 1.6-fold, interferon-γ from 16.0-fold to 2.2-fold, and tumor necrosis factor-α from 16.4-fold to 1.8-fold. This anti-inflammatory activity seems to be achieved by inhibition of NF-κB p65 activation. Assessment of initiation of ROS generation and cell metabolism shows significant protective effects of these two novel TSPO ligands. The IL-10 and IL-13 levels were not affected by any of the TSPO ligands. Thus, it appears that the ligands suppress the LPS-induced activation of some inflammatory responses of microglia. Such immunomodulatory effects may be relevant to the pharmacotherapy of neuro-inflammatory diseases.

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Role of selenium-containing proteins in T-cell and macrophage function

Proceedings of The Nutrition Society ◽

10.1017/s002966511000176x ◽

2010 ◽

Vol 69 (3) ◽

pp. 300-310 ◽

Cited By ~ 58

Author(s):

Bradley A. Carlson ◽

Min-Hyuk Yoo ◽

Rajeev K. Shrimali ◽

Robert Irons ◽

Vadim N. Gladyshev ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Immune Function ◽

Inflammatory Responses ◽

Inflammatory Diseases ◽

Cell Receptor ◽

Lymphoid Tissues ◽

Protein Gel ◽

Species Production

Selenium (Se) has been known for many years to have played a role in boosting the immune function, but the manner in which this element acts at the molecular level in host defence and inflammatory diseases is poorly understood. To elucidate the role of Se-containing proteins in the immune function, we knocked out the expression of this protein class in T-cells or macrophages of mice by targeting the removal of the selenocysteine tRNA gene using loxP-Cre technology. Mice with selenoprotein-less T-cells manifested reduced pools of mature and functional T-cells in lymphoid tissues and an impairment in T-cell-dependent antibody responses. Furthermore, selenoprotein deficiency in T-cells led to an inability of these cells to suppress reactive oxygen species production, which in turn affected their ability to proliferate in response to T-cell receptor stimulation. Selenoprotein-less macrophages, on the other hand, manifested mostly normal inflammatory responses, but this deficiency resulted in an altered regulation in extracellular matrix-related gene expression and a diminished migration of macrophages in a protein gel matrix. These observations provided novel insights into the role of selenoproteins in the immune function and tissue homeostasis.

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Update on the Role of Cannabinoid Receptors after Ischemic Stroke

Mediators of Inflammation ◽

10.1155/2012/824093 ◽

2012 ◽

Vol 2012 ◽

pp. 1-8 ◽

Cited By ~ 24

Author(s):

Luciano S. A. Capettini ◽

Silvia Q. Savergnini ◽

Rafaela F. da Silva ◽

Nikos Stergiopulos ◽

Robson A. S. Santos ◽

...

Keyword(s):

Ischemic Stroke ◽

Cannabinoid Receptors ◽

Inflammatory Diseases ◽

Receptor Activation ◽

Protective Effects ◽

Peripheral Tissues ◽

Transmembrane Receptors ◽

Anti Inflammatory

Cannabinoids are considered as key mediators in the pathophysiology of inflammatory diseases, including atherosclerosis. In particular, they have been shown to reduce the ischemic injury after acute cardiovascular events, such as acute myocardial infarction and ischemic stroke. These protective and anti-inflammatory properties on peripheral tissues and circulating inflammatory have been demonstrated to involve their binding with both selective cannabinoid type 1 (CB1) and type 2 (CB2) transmembrane receptors. On the other hands, the recent discoveries of novel different classes of cannabinoids and receptors have increased the complexity of this system in atherosclerosis. Although only preliminary data have been reported on the activities of novel cannabinoid receptors, several studies have already investigated the role ofCB1andCB2receptors in ischemic stroke. WhileCB1receptor activation has been shown to directly reduce atherosclerotic plaque inflammation, controversial data have been shown on neurotransmission and neuroprotection after stroke. Given its potent anti-inflammatory activities on circulating leukocytes, theCB2activation has been proven to produce protective effects against acute poststroke inflammation. In this paper, we will update evidence on different cannabinoid-triggered avenues to reduce inflammation and neuronal injury in acute ischemic stroke.

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