Cyclophilin A Impairs Efferocytosis and Accelerates Atherosclerosis by Overexpressing CD 47 and Down-Regulating Calreticulin

Impairment of efferocytosis in apoptotic macrophages is a known determinant of the severity of atherosclerosis and the vulnerability of plaques to rupture. The precise mechanisms involved in impaired efferocytosis are unclear. Given the well-recognized role of the inflammatory cytokine cyclophilin A (Cyp A) in modulating several atherogenic mechanisms in high-glucose primed monocytes, we investigated the role of Cyp A in macrophage efferocytosis. The efficiency of efferocytosis in RAW 264.7 macrophages grown in vitro and primed with cyclophilin A was assessed using flow cytometry and confocal assays. Cholesterol content in cells was measured using cell-based cholesterol efflux assay. Proteomic analysis and bioinformatics tools were employed to decipher the link between cyclophilin A and the known ligand receptors involved in efferocytosis. Cyclophilin A was found to impair efferocytosis in apoptotic macrophages by reducing ABCA1-mediated cholesterol efflux in foam cells derived from macrophages. Cyclophilin A-primed macrophages showed an increase in expression of the don’t-eat-me signal CD 47 and a decrease in the expression of the eat-me signal, calreticulin. Phagocytosis was restored upon silencing of cyclophilin A. New Zealand white rabbits were fed a high-fat diet, and lesions in their aortae were analyzed histologically for evidence of atherosclerosis and the expression of Cyp A, CD 47 and calreticulin, the ligand receptor involved in efferocytosis. Gene and protein expressions in aortae and macrophages were analyzed by real-time PCR and Western blotting. Cyclophilin A, via its effects on the expression of CD 47 and calreticulin, impairs efferocytosis in apoptotic macrophages. Together with its impact on cholesterol efflux from macrophages, these effects can amplify other mechanisms of Cyp A in accelerating the progression of atherosclerosis.

Download Full-text

Uremic Apelin and Leucocytic Angiotensin-Converting Enzyme 2 in CKD Patients

Toxins ◽

10.3390/toxins12120742 ◽

2020 ◽

Vol 12 (12) ◽

pp. 742

Author(s):

Bogusz Trojanowicz ◽

Christof Ulrich ◽

Matthias Girndt

Keyword(s):

Angiotensin Converting Enzyme ◽

Healthy Controls ◽

Converting Enzyme ◽

Blood Pressure Lowering ◽

Angiotensin Converting Enzyme 2 ◽

Pressure Lowering ◽

The Impact ◽

Progression Of Atherosclerosis

Apelin peptides (APLN) serve as second substrates for angiotensin-converting enzyme 2 (ACE2) and, in contrast to angiotensin II (AngII), exert blood-pressure lowering and vasodilatation effects through binding to G-coupled APLN receptor (APLNR). ACE2-mediated cleavage of the APLN may reduce its vasodilatory effects, but decreased ACE2 may potentiate the hypotensive properties of APLN. The role of APLN in uremia is unclear. We investigated the correlations between serum-APLN, leucocytic APLNR, and ACE2 in 32 healthy controls (NP), 66 HD, and 24 CKD3–5 patients, and the impact of APLN peptides on monocytic behavior and ACE2 expression under uremic conditions in vitro. We observed that serum APLN and leucocytic APLNR or SLCO2B1 were significantly elevated in uremic patients and correlated with decreased ACE2 on uremic leucocytes. APLN-treated THP-1 monocytes revealed significantly increased APLNR and ACE2, and reduced TNFa, IL-6, and MCSF. Uremic toxins induced a dramatic increase of miR-421 followed by significant reduction of ACE2 transcripts, partially counteracted with APLN-13 and -36. APLN-36 triggered the most potent transmigration and reduction of endothelial adhesion. These results suggest that although APLN peptides may partly protect against the decay of monocytic ACE2 transcripts, uremic milieu is the most dominant modulator of local ACE2, and likely to contribute to the progression of atherosclerosis.

Download Full-text

Mast Cells in Cardiovascular Disease: From Bench to Bedside

International Journal of Molecular Sciences ◽

10.3390/ijms20143395 ◽

2019 ◽

Vol 20 (14) ◽

pp. 3395 ◽

Cited By ~ 6

Author(s):

Hermans ◽

Lennep ◽

van Daele ◽

Bot

Keyword(s):

Cardiovascular Disease ◽

Mast Cells ◽

Animal Studies ◽

Intraplaque Hemorrhage ◽

Hematological Disease ◽

Plaque Instability ◽

Clonal Proliferation ◽

Progression Of Atherosclerosis

Mast cells are pluripotent leukocytes that reside in the mucosa and connective tissue. Recent studies show an increased prevalence of cardiovascular disease among patients with mastocytosis, which is a hematological disease that is characterized by the accumulation of mast cells due to clonal proliferation. This association suggests an important role for mast cells in cardiovascular disease. Indeed, the evidence establishing the contribution of mast cells to the development and progression of atherosclerosis is continually increasing. Mast cells may contribute to plaque formation by stimulating the formation of foam cells and causing a pro-inflammatory micro-environment. In addition, these cells are able to promote plaque instability by neo-vessel formation and also by inducing intraplaque hemorrhage. Furthermore, mast cells appear to stimulate the formation of fibrosis after a cardiac infarction. In this review, the available data on the role of mast cells in cardiovascular disease are summarized, containing both in vitro research and animal studies, followed by a discussion of human data on the association between cardiovascular morbidity and diseases in which mast cells are important: Kounis syndrome, mastocytosis and allergy.

Download Full-text

Cyclophilin A plays an important role in embryo implantation through activating Stat3

Reproduction ◽

10.1530/rep-20-0187 ◽

2020 ◽

Vol 160 (3) ◽

pp. 343-351

Author(s):

Tao Yu ◽

Shuai Lin ◽

Rui Xu ◽

Tian-Xi Du ◽

Yang Li ◽

...

Keyword(s):

Embryo Implantation ◽

Specific Inhibitor ◽

Cyclophilin A ◽

Cellular Functions ◽

Ovariectomized Mice ◽

Inflammatory Stimuli ◽

Implantation Sites ◽

Cypa Expression

Embryo implantation is a crucial step for the successful establishment of mammalian pregnancy. Cyclophilin A (CYPA) is a ubiquitously expressed intracellular protein and is secreted in response to inflammatory stimuli to regulate diverse cellular functions. However, there are currently no reports about the role of CYPA in embryo implantation. Here, we examine the expression pattern of CYPA during mouse early pregnancy and explore the potential role of CYPA during implantation. CYPA is expressed in the subluminal stroma surrounding the implanting blastocyst on day 5 of pregnancy, but not at inter-implantation sites. In ovariectomized mice, estrogen and progesterone significantly stimulate CYPA expression. When pregnant mice are injected intraperitoneally with CYPA inhibitor, the numbers of implantation sites are significantly reduced. Using an in vitro stromal cell culture system, Ppia siRNA knockdown of CYPA and CYPA-specific inhibitor treatment partially inhibits levels of CD147, MMP3 and MMP9. Decreased CYPA expression also significantly inhibits Stat3 activity and expands estrogen responsiveness. Taken together, CYPA may play an important role during mouse embryo implantation.

Download Full-text

Relationship between HDL Cholesterol Efflux Capacity, Calcium Coronary Artery Content, and Antibodies against ApolipoproteinA-1 in Obese and Healthy Subjects

Journal of Clinical Medicine ◽

10.3390/jcm8081225 ◽

2019 ◽

Vol 8 (8) ◽

pp. 1225 ◽

Cited By ~ 6

Author(s):

Nicolas Vuilleumier ◽

Sabrina Pagano ◽

Fabrizio Montecucco ◽

Alessandra Quercioli ◽

Thomas H. Schindler ◽

...

Keyword(s):

Coronary Artery ◽

Cholesterol Efflux ◽

Positive Association ◽

Hdl Cholesterol ◽

Cholesterol Content ◽

Cholesterol Efflux Capacity ◽

Clinical Observations ◽

Framingham Risk ◽

Obese Subjects

Aims: To explore the associations between cholesterol efflux capacity (CEC), coronary artery calcium (CAC) score, Framingham risk score (FRS), and antibodies against apolipoproteinA-1 (anti-apoA-1 IgG) in healthy and obese subjects (OS). Methods and Results: ABCA1-, ABCG1-, passive diffusion (PD)-CEC and anti-apoA-1 IgG were measured in sera from 34 controls and 35 OS who underwent CAC score determination by chest computed tomography. Anti-apoA-1 IgG ability to modulate CEC and macrophage cholesterol content (MCC) was tested in vitro. Controls and OS displayed similar ABCG1-, ABCA1-, PD-CEC, CAC and FRS scores. Logistic regression analyses indicated that FRS was the only significant predictor of CAC lesion. Overall, anti-apoA-1 IgG were significantly correlated with ABCA1-CEC (r = 0.48, p < 0.0001), PD-CEC (r = −0.33, p = 0.004), and the CAC score (r = 0.37, p = 0.03). ABCA1-CEC was correlated with CAC score (r = 0.47, p = 0.004) and FRS (r = 0.18, p = 0.29), while PD-CEC was inversely associated with the same parameters (CAC: r = −0.46, p = 0.006; FRS: score r = −0.40, p = 0.01). None of these associations was replicated in healthy controls or after excluding anti-apoA-1 IgG seropositive subjects. In vitro, anti-apoA-1 IgG inhibited PD-CEC (p < 0.0001), increased ABCA1-CEC (p < 0.0001), and increased MCC (p < 0.0001). Conclusions: We report a paradoxical positive association between ABCA1-CEC and the CAC score, with the latter being inversely associated with PD in OS. Corroborating our clinical observations, anti-apoA-1 IgG enhanced ABCA1 while repressing PD-CEC, leading to MCC increase in vitro. These results indicate that anti-apoA-1 IgG have the potential to interfere with CEC and macrophage lipid metabolism, and may underpin paradoxical associations between ABCA1-CEC and cardiovascular risk.

Download Full-text

Nascent HDL (High-Density Lipoprotein) Discs Carry Cholesterol to HDL Spheres

Arteriosclerosis Thrombosis and Vascular Biology ◽

10.1161/atvbaha.120.313906 ◽

2020 ◽

Vol 40 (5) ◽

pp. 1182-1194 ◽

Cited By ~ 1

Author(s):

Alexei V. Navdaev ◽

Lorenzo Sborgi ◽

Samuel D. Wright ◽

Svetlana A. Didichenko

Keyword(s):

High Density Lipoprotein ◽

Cholesterol Efflux ◽

Density Lipoprotein ◽

Fluorescent Labeling ◽

High Density ◽

Atp Binding Cassette Transporter ◽

Spherical Plasma ◽

Apo Ai

Objective: To characterize the fate of protein and lipid in nascent HDL (high-density lipoprotein) in plasma and explore the role of interaction between nascent HDL and mature HDL in promoting ABCA1 (ATP-binding cassette transporter 1)-dependent cholesterol efflux. Approach and Results: Two discoidal species, nascent HDL produced by RAW264.7 cells expressing ABCA1 (LpA-I [apo AI containing particles formed by incubating ABCA1-expressing cells with apo AI]), and CSL112, human apo AI (apolipoprotein AI) reconstituted with phospholipids, were used for in vitro incubations with human plasma or purified spherical plasma HDL. Fluorescent labeling and biotinylation of HDL were employed to follow the redistribution of cholesterol and apo AI, cholesterol efflux was measured using cholesterol-loaded cells. We show that both nascent LpA-I and CSL112 can rapidly fuse with spherical HDL. Redistribution of the apo AI molecules and cholesterol after particle fusion leads to the formation of (1) enlarged, remodeled, lipid-rich HDL particles carrying lipid and apo AI from LpA-I and (2) lipid-poor apo AI particles carrying apo AI from both discs and spheres. The interaction of discs and spheres led to a greater than additive elevation of ABCA1-dependent cholesterol efflux. Conclusions: These data demonstrate that although newly formed discs are relatively poor substrates for ABCA1, they can interact with spheres to produce lipid-poor apo AI, a much better substrate for ABCA1. Because the lipid-poor apo AI generated in this interaction can itself become discoid by the action of ABCA1, cycles of cholesterol efflux and disc-sphere fusion may result in net ABCA1-dependent transfer of cholesterol from cells to HDL spheres. This process may be of particular importance in atherosclerotic plaque where cholesterol acceptors may be limiting.

Download Full-text

MicroRNA-30-3p Suppresses Inflammatory Factor-Induced Endothelial Cell Injury by Targeting TCF21

Mediators of Inflammation ◽

10.1155/2019/1342190 ◽

2019 ◽

Vol 2019 ◽

pp. 1-14 ◽

Cited By ~ 5

Author(s):

Zhenyu Zhou ◽

Yu Chen ◽

Dongying Zhang ◽

Shiyong Wu ◽

Tao Liu ◽

...

Keyword(s):

Endothelial Cell ◽

Functional Role ◽

Target Gene ◽

Luciferase Reporter ◽

Inflammatory Factor ◽

Expression Levels ◽

Potential Biomarker ◽

Progression Of Atherosclerosis

Atherosclerosis is one of the leading causes of mortality worldwide. Growing evidence suggested that miRNAs contributed to the progression of atherosclerosis. miR-30-5p was found involved in various diseases. However, the role of miR-30-5p in regulation of atherosclerosis is not known. Here, we aim to investigate the effects of miR-30-5p on regulating the progression of atherosclerosis. The expression levels of miR-30-5p in serum collected from atherosclerosis patients and normal healthy people were analyzed by qRT-PCR. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway bioinformatics were carried out to reveal the possible signaling pathways involved in the mode of action of miR-30-5p. A potential target gene of miRNA-30-5p was searched and examined by a luciferase reporter assay. ELISA, Western blot, proliferation, and flow cytometry assays were performed to assess the biological functional role of miR-30-5p in vitro. Also, an in vitro monocyte-endothelial cell coculture model was used to study the functional role of miR-30-5p in atherosclerosis. We found that miR-30-5p was significantly decreased in serum samples from atherosclerosis patients compared with control subjects. GO and KEGG analysis results showed that miR-30-5p is highly associated with genetic profile of cardiovascular disease. TCF21 was verified as a target gene of miR-30-5p. Overexpression of miR-30-5p in THP-1 not only protected endothelial cell viability but also inhibited endothelial cell apoptosis, and similar results were observed in cells with that of TCF21 knocked down. Moreover, miR-30-5p decreased the expression levels of lactate dehydrogenase (LDH) and tumor necrosis factor-α (TNF-α) and reduced reactive oxygen species (ROS) accumulation. NF-κB and MAPK/p38 pathways played an indispensable role in the protection ability of miR-30-5p against atherosclerosis. Our results reveal that miR-30-5p suppresses the progression of atherosclerosis through targeting TCF21 in vitro. Therefore, the miR-30-5p-TCF21-MAPK/p38 signaling pathway may be a potential biomarker or therapeutic target in atherosclerosis.

Download Full-text

The Role of SGLT2 Inhibitors in Atherosclerosis: A Narrative Mini-Review

Frontiers in Pharmacology ◽

10.3389/fphar.2021.751214 ◽

2021 ◽

Vol 12 ◽

Author(s):

Aurélie Pahud de Mortanges ◽

Dante Salvador Jr. ◽

Markus Laimer ◽

Taulant Muka ◽

Matthias Wilhelm ◽

...

Keyword(s):

Glycemic Control ◽

Subclinical Atherosclerosis ◽

Intima Media Thickness ◽

Carotid Intima Media Thickness ◽

Major Adverse Cardiovascular Events ◽

Atherosclerotic Cardiovascular Disease ◽

Urinary Glucose ◽

Progression Of Atherosclerosis

Objective: Sodium glucose cotransporter 2 inhibitors (SGLT2-is) are antidiabetic drugs that improve glycemic control by limiting urinary glucose reuptake in the proximal tubule. SGLT2-is might suppress atherosclerotic processes and ameliorate the prognosis of patients with diabetes mellitus diagnosed with or at high risk of atherosclerotic cardiovascular disease (ASCVD). In this mini review, we examine the role of SGLT2-is in the development and progression of atherosclerosis throughout its spectrum, from subclinical atherosclerosis to ASCVD.Data Sources—PubMed and Google Scholar were searched for publications related to SGLT2-is and atherosclerosis. All types of articles were considered, including clinical trials, animal studies, in vitro observations, and reviews and meta-analyses. Data were examined according to their impact and clinical relevance.Synopsis of Content—We first review the underlying mechanisms of SGLT2-is on the development and progression of atherosclerosis, including favorable effects on lipid metabolism, reduction of systemic inflammation, and improvement of endothelial function. We then discuss the putative impact of SGLT2-is on the formation, composition, and stability of atherosclerotic plaque. Furthermore, we evaluate the effects of SGLT2-is in subclinical atherosclerosis assessed by carotid intima media thickness and pulse wave velocity. Subsequently, we summarize the effects of SGLT2-is in ASCVD events, including ischemic stroke, angina pectoris, myocardial infarction, revascularization, and peripheral artery disease, as well as major adverse cardiovascular events, cardiovascular mortality, heart failure, and chronic kidney disease. Moreover, we examine factors that could modify the role of SGLT2-is in atherosclerosis, including sex, age, diabetes, glycemic control, ASCVD, and SGLT2-i compounds. Additionally, we propose future directions that can improve our understanding of SGLT2-is and atherosclerosis.

Download Full-text

Cyclophilin A/CD147 Induces the Epithelial-to-mesenchymal Transition and Renal Fibrosis in Chronic Allograft Dysfunction by Regulating MAPK Signaling

10.21203/rs.3.rs-310337/v1 ◽

2021 ◽

Author(s):

Xuzhong Liu ◽

Zhiwang Tang ◽

Xi Jiang ◽

Tianwei Wang ◽

Lun Zhao ◽

...

Keyword(s):

Renal Transplant ◽

Epithelial To Mesenchymal Transition ◽

Renal Allograft ◽

Cyclophilin A ◽

Mapk Signaling ◽

Chronic Allograft Dysfunction ◽

Mesenchymal Transition ◽

Allograft Dysfunction

Abstract Objectives: Our study was designed to explore the role of Cyclophilin A (CyPA)/CD147 interactions in renal allograft fibrosis and chronic allograft dysfunction (CAD). Methods and materials: A rat renal transplant model with significant CAD was successfully identified. Renal allograft tissues and blood samples were collected. HE, Masson and immunohistochemistry staining were performed. Then human HK-2 cells were intervened by certain concentrations of CyPA, and total protein and mRNA were extracted. Western blot assay and PCR were performed to explore the protein and mRNA expression of CyPA, CD147 and epithelial-to-mesenchymal transition (EMT)-related biomarkers. CD147 siRNA and specific inhibitor of MAPK were used to explore the involved cellular mechanism.Results: We have successfully established and identified a 20-weeks renal transplant CAD model. We observed significant distributed and expressed CyPA and CD147 in the renal allograft fibrosis tissues. We also found the significant expression of CD147 and EMT-related markers in the HK-2 cells stimulated by CyPA. The CD147 siRNA confirmed the previous results in vitro. The selective inhibition of MAPK suggested the notable role of MAPK signaling pathway in the CyP/CD147 interactions involved in renal allograft fibrosis.Conclusions: Our study reported the positive relationship of CyPA/CD147 interactions with the renal allograft dysfunction. In vitro study suggested that CyPA could bind to CD147 and then induce the development of EMT process by MAPK signaling, thus contributing to the renal allograft fibrosis and CAD.

Download Full-text

260Identification of differential roles of microRNA-33a and -33b during atherosclerosis progression with genetically modified mice

European Heart Journal ◽

10.1093/eurheartj/ehz747.0076 ◽

2019 ◽

Vol 40 (Supplement_1) ◽

Author(s):

T Horie ◽

S Koyama ◽

T Kimura ◽

K Ono

Keyword(s):

Bone Marrow ◽

Serum Cholesterol ◽

Cholesterol Efflux ◽

Target Genes ◽

Genetically Modified ◽

Expression Levels ◽

Cholesterol Efflux Capacity ◽

Predominant Expression ◽

Progression Of Atherosclerosis

Abstract Background MicroRNAs (miRs) are small non-protein-coding RNAs that bind to specific mRNAs and inhibit translation or promote mRNA degradation. Recent reports, including ours, indicated that miR-33a located within the intron of sterol regulatory element-binding factor (SREBF) 2 targets cholesterol transporter ATP-binding cassette protein A1 (ABCA1) or other anti-atherogenic targets and contributes to atherogenesis. Its inhibition or deletion is known to result in the amelioration of atherosclerosis. However, mice lack the other member of miR-33 family, miR-33b, which exists in humans. Precise evaluation and comparison of the responsibilities of these two miRs during the progression of atherosclerosis are essential and need to be investigated. Methods and results The difference between miR-33a and miR-33b in vitro and in vivo were analyzed from multiple directions using genetically modified miR-33a knock-out (KO) and miR-33b knock-in (KI) humanized mice. At first, we performed transcriptomic analysis of primary cultured hepatocytes transfected with synthetic miR-33a, miR-33b, and a control miR and found similar potential target repression and targeting motif of miR-33a and miR-33b in vitro. However, we noticed distinct expression patterns of miR-33a and miR-33b in several organs. By crossing miR-33a KO and miR-33b KI mice, we established four strains with or without miR-33a and miR-33b. Comparison of these strains showed distinct distribution and regulation of miR-33 family. In particular, comparison between mice with only miR-33a (wild-type mice) and mice with only miR-33b (miR-33a−/− miR-33b+/+) revealed 4-fold predominant expression of miR-33b in the liver. Such differential expression resulted in a reduced expression of target genes such as ABCA1 and worsened serum cholesterol profile in mice with only miR-33b. On the contrary, in macrophages the expression levels of miR-33 family genes were similar and their effects on target genes and cholesterol efflux capacity to ApoA-I or HDL cholesterol (HDL-C) were almost comparable. To evaluate the whole body atherogenic potency, we developed ApoE−/− miR-33a+/+ miR-33b−/− mice and ApoE−/− miR-33a−/− miR-33b+/+ mice. ApoE−/− miR-33a−/− miR-33b+/+ mice developed increased atherosclerotic plaque compared with ApoE−/− miR-33a+/+ miR-33b−/− mice, in line with the predominant expression of miR-33b in the liver and decreased serum HDL-C levels whose lower cholesterol efflux capacity were confirmed in 3H-labeled macrophages. On the contrary, a bone marrow transplantation study showed no significant difference in atherosclerosis and serum cholesterol profile, and this was consistent with the relevant expression levels of miR-33a and miR-33b in bone marrow cells. Conclusions miR-33 family exhibited differences in distribution and regulation, and particularly in the progression of atherosclerosis, miR-33b would be more potent than miR-33a.

Download Full-text

Role of R-spondin 2 in arterial lymphangiogenesis and atherosclerosis

Cardiovascular Research ◽

10.1093/cvr/cvaa244 ◽

2020 ◽

Cited By ~ 1

Author(s):

Bhupesh Singla ◽

Hui-Ping Lin ◽

Alex Chen ◽

WonMo Ahn ◽

Pushpankur Ghoshal ◽

...

Keyword(s):

Nitric Oxide ◽

Cholesterol Efflux ◽

Matrix Protein ◽

Low Density Lipoprotein ◽

Density Lipoprotein ◽

Lymphatic Drainage ◽

Control Treatment

Abstract Aims Impaired lymphatic drainage of the arterial wall results in intimal lipid accumulation and atherosclerosis. However, the mechanisms regulating lymphangiogenesis in atherosclerotic arteries are not well understood. Our studies identified elevated levels of matrix protein R-spondin 2 (RSPO2) in atherosclerotic arteries. In this study, we investigated the role of RSPO2 in lymphangiogenesis, arterial cholesterol efflux into lesion-draining lymph nodes (LNs) and development of atherosclerosis. Methods and results The effect of RSPO2 on lymphangiogenesis was investigated using human lymphatic endothelial cells (LEC) in vitro and implanted Matrigel plugs in vivo. Cellular and molecular approaches, pharmacological agents, and siRNA silencing of RSPO2 receptor LGR4 were used to investigate RSPO2-mediated signalling in LEC. In vivo low-density lipoprotein (LDL) tracking and perivascular blockade of RSPO2–LGR4 signalling using LGR4-extracellular domain (ECD) pluronic gel in hypercholesterolemic mice were utilized to investigate the role of RSPO2 in arterial reverse cholesterol transport and atherosclerosis. Immunoblotting and imaging experiments demonstrated increased RSPO2 expression in human and mouse atherosclerotic arteries compared to non-atherosclerotic controls. RSPO2 treatment inhibited lymphangiogenesis both in vitro and in vivo. LGR4 silencing and inhibition of RSPO2–LGR4 signalling abrogated RSPO2-induced inhibition of lymphangiogenesis. Mechanistically, we found that RSPO2 suppresses PI3K-AKT-endothelial nitric oxide synthase (eNOS) signalling via LGR4 and inhibits activation of the canonical Wnt-β-catenin pathway. ApoE−/− mice treated with LGR4-ECD developed significantly less atherosclerosis compared with control treatment. Finally, increased arterial lymphatic vessel density and improved lymphatic drainage of fluorescently labelled LDL to deep cervical LNs were observed in LGR4-ECD-treated mice. Conclusion These findings demonstrate that RSPO2 inhibits lymphangiogenesis via LGR4 and downstream impairment of AKT-eNOS-nitric oxide signalling. These results may also inform new therapeutic strategies to promote lymphangiogenesis and improve cholesterol efflux from atherosclerotic arteries.

Download Full-text