Abstract 239: Deficiency of Macrophage Epsins Impedes Atherosclerosis by Inhibiting LRP-1 Internalization and Degradation

2016 ◽  
Vol 36 (suppl_1) ◽  
Author(s):  
Megan L Brophy ◽  
Ashiqur Rahman ◽  
Yunzhou Dong ◽  
Hao Wu ◽  
Kandice L Tessneer ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Foam Cell ◽  
Cell Formation ◽  
Atherosclerotic Lesion ◽  
Gene Profiling ◽  
Foam Cell Formation ◽  
Macrophage Phenotype ◽  
M1 Macrophage ◽  
Anti Inflammatory ◽  
Inflammatory Macrophage

Background: Atherosclerosis is caused by the chronic activation of the vascular endothelium and immune and inflammatory cell infiltration of the vascular wall, leading to enhanced inflammation and lipid accumulation. Understanding the molecular mechanisms underlying this disease is critical for the development of new therapies. Epsins are a family of ubiquitin-binding endocytic adaptors. However, their role in vascular inflammation is poorly understood. Our goal is to define the novel role of epsins in regulating atherogenesis. Methods and Results: We engineered mice with specific deletion of epsins in myeloid cells (MΦ-DKO). Strikingly, MΦ-DKO mice on an ApoE-/- background fed western diet exhibited reduced atherosclerotic lesion and foam cell accumulation, and diminished recruitment of immune or inflammatory cells to aortas by FACS analysis. In primary macrophages, epsin deficiency impaired foam cell formation by Oil Red O staining, and suppressed the pro-inflammatory M1 macrophage phenotype but increased the anti-inflammatory macrophage phenotype by gene profiling. Epsin deficiency did not alter levels of LDL scavenger receptors, or reverse cholesterol transport proteins, but did increase total and surface levels of LRP-1, a protein with anti-inflammatory and anti-atherosclerotic properties. Mechanistically, Epsin interacts with LRP-1 via epsin’s UIM domain. LPS treatment increased LRP-1 ubiquitination and subsequent binding to epsin, suggesting that epsin promotes the ubiquitin-dependent internalization and degradation of LRP-1. Accordingly, macrophages isolated from MΦ-DKO mice on LRP-1 heterozygous background restored the pro-inflammatory phenotype. Conclusions: Epsins promote atherogenesis by facilitating pro-inflammatory macrophage recruitment and potentiating foam cell formation by downregulating LRP-1 implicating that targeting the epsin-LRP-1 interaction may serve as a novel therapeutic strategy to treat atheromas.

Abstract 94: Deficiency of Epsins in Macrophages Ameliorates Atherosclerosis by Attenuating Inflammation

2017 ◽  
Vol 37 (suppl_1) ◽  
Author(s):  
Megan L Brophy ◽  
Yunzhou Dong ◽  
Hao Wu ◽  
Kai Song ◽  
Ashiqur Rahman ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Inflammatory Cell ◽  
Foam Cell ◽  
Oxidized Ldl ◽  
Cell Formation ◽  
Foam Cell Formation ◽  
Macrophage Phenotype ◽  
M1 Macrophage ◽  
Anti Inflammatory ◽  
Inflammatory Macrophage

Background: Atherosclerosis is caused by the immune and inflammatory cell infiltration of the vascular wall, leading to enhanced inflammation and lipid accumulation. Understanding the molecular mechanisms underlying this disease is critical for the development of new therapies. Our recently studies demonstrate that endothelial epsins, a family of ubiquitin-binding endocytic adaptors are critical regulators of atherosclerosis. However, whether epsins in macrophages play a role in regulating vascular inflammation is unknown. We hypothesize that epsins in macrophages promote inflammation to facilitate atherogenesis. Methods and Results: We engineered myeloid cell-specific epsins double knockout mice (MΦ-DKO) on an ApoE-/- background fed western diet. Strikingly, these mice exhibited reduced atherosclerotic lesion formation, diminished immune and inflammatory cell recruitment to aortas and reduced cleaved caspase 3 staining but increased α-SMA staining within aortic root sections. Epsin deficiency hindered foam cell formation, suppressed the pro-inflammatory M1 macrophage phenotype but increased the anti-inflammatory macrophage phenotype, and enhanced efferocytosis in primary macrophages. Mechanistically, we show that epsin loss specifically increases total and surface levels of LRP-1, a protein with anti-inflammatory properties without altering levels of LDL scavenger receptors. We further show that epsin and LRP-1 interact via epsin’s UIM domain. Oxidized LDL treatment increased LRP-1 ubiquitination and subsequent binding to epsin while mutation of cytoplasmic lysine residues attenuated LRP-1 ubiquitination, suggesting that epsin promotes the ubiquitin-dependent internalization and degradation of LRP-1. Importantly, MΦ-DKO/ApoE null mice on LRP-1 heterozygous background restored atherosclerosis, suggesting that epsin-mediated LRP-1 downregulation in macrophages plays a pivotal role in propelling atherogenesis. Conclusions: Macrophage epsins promote atherogenesis, in part, by facilitating pro-inflammatory macrophage recruitment and potentiating foam cell formation by downregulating LRP-1, implicating that targeting epsin in macrophages may serve as a novel therapeutic strategy to treat atheroma.

scholarly journals eIF6 Promotes Inflammatory Macrophage Phenotype, Foam Cell Formation and Atherosclerosise

2021 ◽  
Author(s):  
Junnian Zheng ◽  
Renjin Chen ◽  
Xuemei Xian ◽  
xiaoqiang Zhan ◽  
Jiajia Chang ◽  
...  
Keyword(s):  
Foam Cell ◽  
Cell Formation ◽  
Western Diet ◽  
Initiation Factor ◽  
Immunofluorescent Staining ◽  
Foam Cell Formation ◽  
Macrophage Phenotype ◽  
Anti Inflammatory ◽  
Inflammatory Macrophage ◽  
Novel Therapeutic

Abstract Background：Atherosclerosis is a chronic inflammatory disease, caused by accumulation of lipid-laden and inflammatory macrophages in the artery wall. Understanding its molecular mechanisms and developing novel therapeutic targets to promote atherosclerotic regression is an important clinical goal.Methods : ApoE-/- and eIF6+/-/ApoE-/- mice were fed Western diet (WD) for 16 weeks. Molecular biology technology were performed to analyze the differences between them.Results: The mechanism by which Eukaryotic initiation factor 6 (eIF6) affects macrophages and atherosclerosis remains to be elucidated. Western blotting and real-time polymerase chain reaction (PCR ) analysis indicated significantly higher expression levels of eIF6 than those in the control in RAW264.7 cells induced by Lipopolysaccharide (LPS) and Interleukin-4 (IL4). We constructed eIF6+/-/ApoE-/- mice, the hematoxylin (HE) and Oil Red O staining analysis indicated that these mice showed a significant decrease in atherosclerotic lesion formation increased anti-inflammatory cell content in aortas, and reduced necrotic core content compared with ApoE-/- mice on a western diet for 16 weeks. eIF6 deficiency suppressed foam cell formation and promoted the anti-inflammatory macrophage phenotype in primary macrophages. More anti-inflammatory populations were observed in blood and atherosclerotic aortas of eIF6+/- ApoE-/- mice by flow cytometry. Immunofluorescent staining analysis obtained the same results.Conclusions: eIF6 deficiency protects against atherosclerosis by promoting the anti-inflammatory macrophage phenotype and reducing macrophage uptake of low-density lipoprotein (LDL), indicating that new insight into eIF6 may reveal a potential novel therapeutic target for the resolution of inflammation in atherosclerosis.

Abstract 17333: Myeloid-Specific Deletion of Epsins 1 and 2 Reduces Atherosclerosis by Preventing LRP-1 Downregulation

Circulation ◽  
2018 ◽  
Vol 138 (Suppl_1) ◽  
Author(s):  
Hong Chen ◽  
Megan Brophy
Keyword(s):  
Molecular Mechanisms ◽  
Inflammatory Cell ◽  
Foam Cell ◽  
Oxidized Ldl ◽  
Atherosclerotic Lesion ◽  
Foam Cell Formation ◽  
Macrophage Phenotype ◽  
Double Knockout ◽  
Cell Content ◽  
Inflammatory Macrophage

Introduction: Atherosclerosis is in part caused by immune and inflammatory cell infiltration into the vascular wall, leading to enhanced inflammation and lipid accumulation in the aortic endothelium. Understanding the molecular mechanisms underlying this disease is critical for the development of new therapies. Our recent studies demonstrate that epsins, a family of ubiquitin-binding endocytic adaptors, are critical regulators of atherogenicity. Given the fundamental contribution lesion macrophages make to fuel atherosclerosis, whether and how myeloid specific epsins promote atherogenesis is an open and significant question. Hypothesis: We hypothesize that myeloid specific epsins regulate lesion macrophage function during atherosclerosis. Methods and Results: We engineered myeloid cell-specific epsins double knockout mice (LysM-DKO)on an ApoE -/- background. On Western diet, these mice exhibited marked decrease in atherosclerotic lesion formation, diminished immune and inflammatory cell content in aortas, and reduced necrotic core content but increased smooth muscle cell content in aortic root sections.Epsins deficiency hindered foam cell formation and suppressed the pro-inflammatory macrophage phenotype but increased efferocytosis and the anti-inflammatory macrophage phenotype in primary macrophages.Mechanistically, we show that epsins loss specifically increased total and surface levels of LRP-1, an efferocytosis receptor with anti-atherosclerotic properties. We further show thatepsin and LRP-1 interact via epsin’s Ubiquitin Interacting Motif (UIM) domain. Oxidized LDL treatment increased LRP-1 ubiquitination and subsequent binding to epsin while mutation of cytoplasmic lysine residues attenuated LRP-1 ubiquitination, suggesting that epsins promote the ubiquitin-dependent internalization and downregulation of LRP-1. Crossing ApoE -/- /LysM-DKO mice onto a LRP-1 heterozygous background restored, in part, atherosclerosis, suggesting that epsin-mediated LRP-1 downregulation in macrophages plays a pivotal role in propelling atherogenesis. Conclusions: Myeloid epsins promote atherogenesis by facilitating pro-inflammatory macrophage recruitment and inhibiting efferocytosis in part by downregulating LRP-1, implicating that targeting epsins in macrophages may serve as a novel therapeutic strategy to treat atherosclerosis. Key words: epsin, macrophage, atherosclerosis, LRP-1, inflammation, efferocytosis

Dynamic Role of Macrophage Sub Types for Development of Atherosclerosis and Potential Use of Herbal Immunomodulators as Imminent Therapeutic Strategy

2020 ◽  
Vol 18 ◽  
Author(s):  
Parimalanandhini Duraisamy ◽  
Sangeetha Ravi ◽  
Mahalakshmi Krishnan ◽  
Catherene M. Livya ◽  
Beulaja Manikandan ◽  
...  
Keyword(s):  
Foam Cell ◽  
Cell Formation ◽  
Atherosclerotic Lesion ◽  
Foam Cell Formation ◽  
Atherosclerosis Progression ◽  
Proinflammatory Mediators ◽  
M1 Macrophage ◽  
Tnf Α ◽  
Inflammatory Site

: Atherosclerosis, a major contributor to cardiovascular disease is a global alarm causing mortality worldwide. Being a progressive disease in the arteries, it mainly causes recruitment of monocytes to the inflammatory sites and subside pathological conditions. Monocyte-derived macrophage mainly acts in foam cell formation by engorging the LDL molecules, oxidizes it into Ox-LDL and leads to plaque deposit development. Macrophages in general differentiate, proliferate and undergo apoptosis at the inflammatory site. Frequently two subtypes of macrophages M1 and M2 has to act crucially in balancing the micro-environmental conditions of endothelial cells in arteries. The productions of proinflammatory mediators like IL-1, IL-6, TNF-α by M1 macrophage has atherogenic properties majorly produced during the early progression of atherosclerotic plaques. To counteract cytokine productions and M1-M2 balance, secondary metabolites (phytochemicals) from plants act as a therapeutic agent in alleviating atherosclerosis progression. This review summarizes the fundamental role of the macrophage in atherosclerotic lesion formation along with its plasticity characteristic as well as recent therapeutic strategies using herbal components and anti-inflammatory cytokines as potential immunomodulators.

Abstract 254: A Novel Role of Endothelial and Macrophage Epsins in Atherosclerosis

2014 ◽  
Vol 34 (suppl_1) ◽  
Author(s):  
Hong Chen
Keyword(s):  
Atherosclerotic Plaque ◽  
Foam Cell ◽  
Cell Formation ◽  
Atherosclerotic Lesion ◽  
Mapk Signaling ◽  
Leukocyte Recruitment ◽  
Foam Cell Formation ◽  
Tlr Signaling ◽  
M1 Macrophage

Background: Epsins are a family of ubiquitin-binding endocytic clathrin adaptors. We recently published that endothelial epsins function as critical regulators of tumor angiogenesis by controlling VEGF signaling (JCI, 2012; ATVB, 2013). Our goal is to define the novel role of epsins in endothelial cells (EC) and macrophages in regulating atherogenesis. Methods and Results: We engineered mice with specific deletion of epsins in EC (EC-DKO) or myeloid cells (MΦ-DKO). Strikingly, either EC-DKO or MΦ-DKO mice on ApoE-/- background fed western diet significantly reduced atherosclerotic lesion formation and foam cell accumulation. FACS analysis revealed that epsin deficiency greatly reduced TNFα and LPS-induced adhesion molecule expression (ICAM-1, VCAM-1, P- and E-selectins, CCR2 and MCP-1) in aortic EC and leukocyte recruitment in aorta. Mechanistically, EC epsins promote TNFR/TLR signaling and NF-κB and MAPK activation by recruiting NEMO, an essential NF-κB activator. In macrophages, epsin deficiency did not alter LDL scavenger receptors, CD36, Lox1 or SRB1, or reverse cholesterol transport proteins, ABCA1 or ABCG1, but did significantly reduce Lucifer Yellow pinocytosis, indicating a major defect in lipid uptake. Oil Red O staining of isolated ApoE-/-/MΦ-DKO macrophages showed little lipid accumulation, suggesting a mechanism in which epsin deficiency impairs foam cell formation. Epsin deficiency also significantly suppressed the pro-inflammatory M1 macrophage phenotype found in plaques thus suggesting an important pro-inflammatory role for epsins in macrophages. Loss of macrophage epsins significantly inhibited TNFα-stimulated activation of NF-κB and MAPK signaling pathways. We also observed a synthetic peptide comprising the epsin ubiquitin-interacting motif (UIM) and lesion homing sequence potently disrupted association of epsins with TNFR/TLR signaling complex in vitro, and inhibited atherosclerotic plaque in vivo. Conclusions: We demonstrate epsins promote atherogenesis by potentiating endothelium activation, leukocyte recruitment, foam cell formation and maintaining pro-inflammatory macrophages within the atherosclerotic plaque, thus suggesting epsins as a novel therapeutic target to combat atherogenesis.

scholarly journals PAK1 Silencing Attenuated Proinflammatory Macrophage Activation and Foam Cell Formation by Increasing PPARγ Expression

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Wen-Lin Cheng ◽  
Quan Zhang ◽  
Bo Li ◽  
Jian-Lei Cao ◽  
Lin Jiao ◽  
...  
Keyword(s):  
Macrophage Activation ◽  
Foam Cell ◽  
Macrophage Polarization ◽  
Cell Formation ◽  
Foam Cell Formation ◽  
M2 Macrophage ◽  
Macrophage Phenotype ◽  
Loss Of Function ◽  
M1 Macrophage ◽  
Pparγ Expression

Macrophage polarization in response to environmental cues has emerged as an important event in the development of atherosclerosis. Compelling evidences suggest that P21-activated kinases 1 (PAK1) is involved in a wide variety of diseases. However, the potential role and mechanism of PAK1 in regulation of macrophage polarization remains to be elucidated. Here, we observed that PAK1 showed a dramatically increased expression in M1 macrophages but decreased expression in M2 macrophages by using a well-established in vitro model to study heterogeneity of macrophage polarization. Adenovirus-mediated loss-of-function approach demonstrated that PAK1 silencing induced an M2 macrophage phenotype-associated gene profiles but repressed the phenotypic markers related to M1 macrophage polarization. Additionally, dramatically decreased foam cell formation was found in PAK1 silencing-induced M2 macrophage activation which was accompanied with alternation of marker account for cholesterol efflux or influx from macrophage foam cells. Moderate results in lipid metabolism and foam cell formation were found in M1 macrophage activation mediated by AdshPAK1. Importantly, we presented mechanistic evidence that PAK1 knockdown promoted the expression of PPARγ, and the effect of macrophage activation regulated by PAK1 silencing was largely reversed when a PPARγ antagonist was utilized. Collectively, these findings reveal that PAK1 is an independent effector of macrophage polarization at least partially attributed to regulation of PPARγ expression, which suggested PAK1-PPARγ axis as a novel therapeutic strategy in atherosclerosis management.

MiR-375 silencing attenuates pro-inflammatory macrophage response and foam cell formation by targeting KLF4

2021 ◽  
Vol 400 (1) ◽  
pp. 112507
Author(s):  
Yanyan Qiu ◽  
Jinyi Xu ◽  
Lihong Yang ◽  
Guihua Zhao ◽  
Jing Ding ◽  
...  
Keyword(s):  
Foam Cell ◽  
Cell Formation ◽  
Foam Cell Formation ◽  
Macrophage Response ◽  
Inflammatory Macrophage

Abstract 57: The Epigenetic Enzyme Kdm6b Controls the Pro-Fibrotic Transcriptome Signature of Foam Cells

2017 ◽  
Vol 37 (suppl_1) ◽  
Author(s):  
Annette E Neele ◽  
Koen H Prange ◽  
Marten A Hoeksema ◽  
Saskia van der Velden ◽  
Tina Lucas ◽  
...  
Keyword(s):  
Foam Cell ◽  
Smooth Muscle Actin ◽  
Cell Formation ◽  
Atherosclerotic Lesion ◽  
Foam Cells ◽  
Foam Cell Formation ◽  
Cell Phenotype ◽  
Sequencing Analysis ◽  
Dependent Manner ◽  
Alpha Smooth Muscle Actin

Aim: Foam cells are a key hallmark of atherosclerotic lesion formation. Within the atherosclerotic lesion macrophages scavenge modified lipoproteins and thereby acquire their foam cell characteristics. Besides their foam cell phenotype, macrophages can have specific inflammation regulatory functions in atherosclerotic lesions. Epigenetic pathways are crucial for monocyte to macrophage differentiation and activation. The H3K27 demethylase Kdm6b (also known as Jmjd3) is regulated in response to various triggers and regulates several modes of macrophage activation. Given the crucial role of macrophage foam cells in atherosclerosis, we here studied Kdm6b in peritoneal foam cells in order to identify regulated pathways. Material and Methods: A myeloid deficient Kdm6b mice (LysMCre-Kdm6b fl/fl ) was generated and bone marrow of Kdm6b wt or Kdm6b del mice was transplanted to irradiated Ldlr -/- mice which were fed a high fat diet for 9 weeks to induce foam cell formation. Peritoneal foam cells from Kdm6b del or Kdm6b wt mice were isolated and used for RNA-sequencing analysis. Results: Among the list of downregulated genes many genes involving fibrosis were affected in Kdm6b deficient foam cells including Collagen genes ( Col1a1 , Col1a2 ), Alpha smooth muscle actin ( Acta2 ) and Fibronectin-1 ( Fn1 ). Pathway analysis on downregulated genes ( P -value < 0.05) indicated that pathways involved in epithelial to mesenchymaltransition (EMT) ( q- value=10 -13 ) and extracellular matrix organization ( q- value=10 -4 ) were significantly downregulated. Pro-fibrotic pathways were thus strongly suppressed in Kdm6b deleted foam cells. Analysis of published datasets of foam cells showed that foam cell formation induces these pro-fibrotic characteristics. Overlay of both data sets indicated that fibrotic genes which are induced upon foam cell formation, are reduced in the absence of Kdm6b. These data suggest that foam cell formation induces a pro-fibrotic gene signature in a Kdm6b-dependent manner. Conclusion: We identified Kdm6b as a novel regulator of the pro-fibrotic signature of peritoneal foam cells.

Differentiation factors and cytokines in the atherosclerotic plaque micro-environment as a trigger for macrophage polarisation

2011 ◽  
Vol 106 (11) ◽  
pp. 763-771 ◽  
Author(s):  
Ine Wolfs ◽  
Marjo Donners ◽  
Menno de Winther
Keyword(s):  
Inflammatory Cell ◽  
Foam Cell ◽  
Cell Formation ◽  
Atherosclerotic Lesion ◽  
Foam Cell Formation ◽  
M1 Macrophages ◽  
Macrophage Polarisation ◽  
Atherosclerotic Lesions ◽  
Differentiation Factors

SummaryThe phenotype of macrophages in atherosclerotic lesions can vary dramatically, from a large lipid laden foam cell to a small inflammatory cell. Classically, the concept of macrophage heterogeneity discriminates between two extremes called either pro-inflammatory M1 macrophages or anti-inflammatory M2 macrophages. Polarisation of plaque macrophages is predominantly determined by the local micro-environment present in the atherosclerotic lesion and is rather more complex than typically described by the M1/M2 paradigm. In this review we will discuss the role of various polarising factors in regulating the phenotypical state of plaque macrophages. We will focus on two main levels of phenotype regulation, one determined by differentiation factors produced in the lesion and the other determined by T-cell-derived polarising cytokines. With foam cell formation being a key characteristic of macrophages during atherosclerosis initiation and progression, these polarisation factors will also be linked to lipid handling of macrophages.

scholarly journals Translocator Protein Localises To CD11b+ Macrophages In Atherosclerosis

2018 ◽  
Author(s):  
Chantal Kopecky ◽  
Elvis Pandzic ◽  
Arvind Parmar ◽  
Jeremy Szajer ◽  
Victoria Lee ◽  
...  
Keyword(s):  
Diagnostic Tool ◽  
Foam Cell ◽  
Cell Formation ◽  
Atherosclerotic Lesion ◽  
Translocator Protein ◽  
Foam Cell Formation ◽  
Chow Diet ◽  
Light Sheet Microscopy ◽  
Macrophage Marker ◽  
Tspo Expression

Background: Atherosclerosis is characterized by lipid deposition, monocyte infiltration and foam cell formation in the artery wall. Translocator protein (TSPO) is abundantly expressed in lipid rich tissues. Recently, TSPO has been identified as a potential diagnostic tool in cardiovascular disease. The purpose of this study was to determine if the TSPO ligand, 18F-PBR111, can identify early atherosclerotic lesions and if TSPO expression can be used to identify distinct macrophage populations during lesion progression. Methods and Results: ApoE-/- mice were maintained on a high-fat diet for 3 or 12 weeks. C57BL/6J mice maintained on chow diet served as controls. Mice were administered 18F-PBR111 intravenously and PET/CT imaged. After euthanasia, aortas were isolated, fixed and optically cleared. Cleared aortas were immunostained with DAPI, and fluorescently labelled with antibodies to-TSPO, the tissue resident macrophage marker F4/80 and the monocyte-derived macrophage marker CD11b. TSPO expression and the macrophage markers were visualised in fatty streaks and mature lesions by light sheet microscopy. While tissue resident F4/80+ macrophages were evident in the arteries of animals without atherosclerosis, no CD11b+ macrophages were observed in these animals. In contrast, mature plaques had high CD11b and low F4/80 expression. A ~3-fold increase in the uptake of 18F-PBR111 was observed in the aortas of atherosclerotic mice relative to controls. Conclusions: Imaging of TSPO expression is a new approach for studying atherosclerotic lesion progression and inflammatory cell infiltration. The TSPO ligand, 18F-PBR111, is a potential clinical diagnostic tool for the detection and quantification of atherosclerotic lesion progression in humans.

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