Translocator Protein Localises To CD11b+ Macrophages In Atherosclerosis

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

Cardiovascular & Hematological Agents in Medicinal Chemistry ◽

10.2174/1871525718666201217163207 ◽

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.

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

Arteriosclerosis Thrombosis and Vascular Biology ◽

10.1161/atvb.37.suppl_1.57 ◽

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.

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

Thrombosis and Haemostasis ◽

10.1160/th11-05-0320 ◽

2011 ◽

Vol 106 (11) ◽

pp. 763-771 ◽

Cited By ~ 114

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.

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Abstract 633: Macrophage SR-BI Suppresses Atherosclerosis by Modulation of Autophagy via VPS34/Belclin-1 Pathway

Arteriosclerosis Thrombosis and Vascular Biology ◽

10.1161/atvb.36.suppl_1.633 ◽

2016 ◽

Vol 36 (suppl_1) ◽

Author(s):

Huan Tao ◽

Patricia G Yancey ◽

John L Blakemore ◽

Youmin Zhang ◽

Lei Ding ◽

...

Keyword(s):

Foam Cell ◽

Oxidized Ldl ◽

Cell Formation ◽

Atherosclerotic Lesion ◽

Beclin 1 ◽

Foam Cell Formation ◽

Aortic Tissue ◽

Type I ◽

Macrophage Foam Cell ◽

Atherosclerotic Lesions

Background: Autophagy modulates vascular cell lipid metabolism, lipid droplet turnover, foam cell formation, cell survival and death, and inflammation. Scavenger receptor class B type I (SR-BI) deficiency causes impaired lysosome function in macrophages and erythrocytes. Methods and Results: Bone marrow transplantation studies were performed in ApoE and LDLR deficient mice to examine the effects of hematopoietic SR-BI deletion on atherosclerotic lesion autophagy. In addition, in vitro studies compared WT versus SR-BI -/- macrophages. Under conditions of cholesterol induced stress, the mRNA and protein levels of critical autophagy players including ATG5, ATG6/Belcin-1, ATG7 and LC3II were decreased by 37.8% to 84.6% (P<0.05 to 0.01) in SR-B1 -/- macrophages and atherosclerotic aortic tissue compared to controls. Electron microscopic analysis showed that SR-BI -/- versus WT macrophages had 80% fewer (P<0.05) autophagsomes in response to cholesterol enrichment. Macrophage SR-BI deficiency led to 1.8-fold (P<0.05) more lipid deposition and 2.5-fold more (P<0.01) apoptosis in response to oxidized LDL. Furthermore, hematopoietic SR-BI deletion caused 2.3 fold (P<0.05) more cell death in aortic atherosclerotic lesions compared to the WT control. Pharmacologic activation of autophagy did not reduce the levels of lipid droplets or cell apoptosis in SR-BI null macrophages vs WT control. WT peritoneal macrophages were used to examine SR-BI subcellular distribution and its interaction with VPS34/Beclin-1. In response to induction of autophagy, macrophage SR-BI was expressed in lysosomes and co-localized with LC3-II. Furthermore, we found that SR-BI directly interacted with the VPS34/Beclin-1 complex. Conclusions: SR-BI deficiency leads to defective autophagy and accelerates macrophage foam cell formation and apoptosis in experimental mouse atherosclerotic lesions. Macrophage SR-BI regulates expression of critical autophagy players and directly modulates autophagy via the VPS34/Beclin-1 pathway, identifying novel targets for the treatment of atherosclerosis.

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Effect of PCSK9 on Vascular Smooth Muscle Cell Functions: A New Player in Atherosclerosis

Current Medicinal Chemistry ◽

10.2174/0929867328666210531150302 ◽

2021 ◽

Vol 28 ◽

Author(s):

Qiong Xiang ◽

WenFeng Liu ◽

JingLin Zeng ◽

YiMing Deng ◽

Juan Peng ◽

...

Keyword(s):

Smooth Muscle ◽

Vascular Smooth Muscle ◽

Foam Cell ◽

Cell Formation ◽

Atherosclerotic Lesion ◽

Foam Cell Formation ◽

Therapeutic Effects ◽

Pcsk9 Inhibitors ◽

Cell Functions

: Proprotein convertase subtilisin/kexin type 9 (PCSK9) is a secretory serine protease that plays multiple biological functions in the regulation of physiological and pathological processes. PCSK9 inhibitors decrease the circulating LDL-cholesterol level with well-known preventive and therapeutic effects on atherosclerosis (AS), but increasing evidence shows that the direct impact of PCSK9 on the vascular wall also plays an important role in atherosclerotic progression. Compared with other vascular cells, a large proportion of PCSK9 is originated from vascular smooth muscle cells (VSMC). Therefore, defining the effect of VSMC-derived PCSK9 on response changes, such as phenotypic switch, apoptosis, autophagy, inflammation, foam cell formation, and calcification of VSMC, helps us better understand the “pleiotropic” effects of VSMC on the atherosclerotic process. In addition, our understanding of the mechanisms of PCSK9 controlling VSMC functions in vivo is far from enough. This review aims to holistically evaluate and analyze the current state of our knowledge regarding PCSK9 actions affecting on VSMC functions and its mechanism in atherosclerotic lesion development. A mechanistic understanding of PCSK9 effects on VSMC will further underpin the success of a new therapeutic strategy targeting AS.

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WO10-OR-6 COMBINED DELETION OF SR-BI AND ABCA1 IN MACROPHAGES DRAMATICALLY ENHANCES MACROPHAGE FOAM CELL FORMATION AND ATHEROSCLEROTIC LESION DEVELOPMENT

Atherosclerosis Supplements ◽

10.1016/s1567-5688(07)70986-8 ◽

2007 ◽

Vol 8 (1) ◽

pp. 11

Author(s):

M. Pennings ◽

R.B. Hildebrand ◽

G. Chimini ◽

T.J. Van Berkel ◽

M. Van Eck

Keyword(s):

Foam Cell ◽

Cell Formation ◽

Atherosclerotic Lesion ◽

Foam Cell Formation ◽

Macrophage Foam Cell ◽

Lesion Development ◽

Atherosclerotic Lesion Development

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Pomegranate Protection against Cardiovascular Diseases

Evidence-based Complementary and Alternative Medicine ◽

10.1155/2012/382763 ◽

2012 ◽

Vol 2012 ◽

pp. 1-20 ◽

Cited By ~ 32

Author(s):

Michael Aviram ◽

Mira Rosenblat

Keyword(s):

Foam Cell ◽

Cell Formation ◽

Atherosclerotic Lesion ◽

Pomegranate Juice ◽

Foam Cell Formation ◽

Atherosclerosis Development ◽

By Products ◽

Lipids Accumulation

The current paper summarizes the antioxidative and antiatherogenic effects of pomegranate polyphenols on serum lipoproteins and on arterial macrophages (two major components of the atherosclerotic lesion), using bothin vitroandin vivohumans and mice models. Pomegranate juice and its by-products substantially reduced macrophage cholesterol and oxidized lipids accumulation, and foam cell formation (the hallmark of early atherogenesis), leading to attenuation of atherosclerosis development, and its consequent cardiovascular events.

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

Arteriosclerosis Thrombosis and Vascular Biology ◽

10.1161/atvb.34.suppl_1.254 ◽

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.

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

Arteriosclerosis Thrombosis and Vascular Biology ◽

10.1161/atvb.36.suppl_1.239 ◽

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.

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