scholarly journals Astragalus Flavone Ameliorates Atherosclerosis and Hepatic Steatosis Via Inhibiting Lipid-Disorder and Inflammation in apoE−/− Mice

2020 ◽  
Vol 11 ◽  
Author(s):  
Chuanrui Ma ◽  
Jing Zhang ◽  
Shu Yang ◽  
Yunqing Hua ◽  
Jing Su ◽  
...  

Atherosclerosis is a major pathogenic driver of cardiovascular diseases. Foam cell formation plays a key role in atherogenesis, which is affected by lipid disorder and inflammation. Therefore, inhibition of foam cell formation is a therapeutic approach for atherosclerosis treatment. Total flavone of Astragalus membranaceus (TFA) is extracted from A. membranaceus that has protective effect on cardiovascular disease. However, the effect of TFA on atherosclerosis and the underlying mechanism remains unknown. In this study, we determined whether TFA could inhibit atherosclerosis and uncovered the underlying mechanism. In vivo, ApoE deficient mice were treated with TFA and high-fat diet for 16 weeks. Subsequently, atherosclerotic lesions, hepatic steatosis and associated genes expression in vitro and in vivo were determined. We found that TFA reduced atherosclerotic lesion size and enhanced plaque stability, which might be attributed to improved lipid disorder, reduced inflammation and decreased monocyte adhesion. Mechanistically, TFA inhibited hepatic steatosis via regulating the genes responsible for lipid metabolism, by which ameliorating the lipid disorder. Moreover, in macrophage, TFA reduced the expression of scavenger receptors such as CD36 and SRA; and promoted the expression of ATP-binding cassette transporter A1 and G1 (ABCA1/G1). More importantly, TFA reduced miR-33 expression and dampened NFκB activity, by which de-repressing ABCA1/G1 activity and inhibiting the inflammation. Collectively, TFA can attenuate atherosclerosis via dual suppression of miR-33 and NFκB pathway, and partially through inhibition of scavenger receptors in macrophage. In addition, TFA ameliorates the hepatic steatosis and lipid disorder, which in turn contributes to the amelioration of atherosclerosis, suggesting that TFA might be a novel therapeutic approach for inhibition of atherosclerosis and hepatic steatosis.

2020 ◽  
Author(s):  
Chuanrui Ma ◽  
Jing Zhang ◽  
Shu Yang ◽  
Yunqing Hua ◽  
Jing Su ◽  
...  

Abstract Background: Atherosclerosis is a major pathogenic factor in cardiovascular diseases during the aging process. Foam cell formation and endothelial dysfunction play a key role in the initiation and development of atherosclerosis, which are affected by lipid disorder and inflammation. Therefore, the drug for inhibition of endothelial dysfunction and the subsequent foam cell formation is a therapeutic approach for atherosclerosis treatment. Total flavone of Astragalus membranaceus (TFA) is extracted from Astragalus membranaceus that has protective effect on cardiovascular disease. However, the effect of TFA on atherosclerosis and the underlying mechanism remains unknown. Methods: In this study, we determined whether TFA could inhibit atherosclerosis; and uncovered the underlying molecular mechanisms. In vivo, apoE deficient mice were treated with TFA contained in high-fat diet for 16 weeks. After treatment, aorta, macrophage and serum samples were collected to determine atherosclerotic lesions, lipid metabolism, and expression of associated genes. Concurrently, we investigated the effect of TFA on monocyte adhesion, foam cell formation, endothelial activation, and macrophage polarization in vitro and in vivo. Results: TFA reduced atherosclerotic plaque size; and enhanced lesion stability by changing the composition of plaque. Moreover, foam cell formation and its accumulation in arterial wall were attenuated by TFA, which might be attributed to improved lipid disorder, reduced inflammation, and decreased monocyte adhesion to endothelial cells. Mechanistically, TFA reduced the expression of scavenger receptor, such as CD36 and SRA; promoted the expression of ATP-binding cassette transporter A1 and G1 (ABCA1/G1). More importantly, TFA reduced the expression of miR-33, a negative regulator of cholesterol efflux as well as positive mediator on inflammation; and concurrently reduced NFkB activity, by which de-repressed ABCA1/G1 activity and inhibited the inflammation. Conclusions: This study demonstrates that TFA can attenuate atherosclerosis via dual inactivation of miR-33 and NFkB signaling pathway and inhibition of scavenger receptors (CD36 and SRA), which suggests that TFA might be a novel therapeutic approach for inhibition of atherosclerosis.


2021 ◽  
Vol 28 ◽  
Author(s):  
Qiong Xiang ◽  
WenFeng Liu ◽  
JingLin Zeng ◽  
YiMing Deng ◽  
Juan Peng ◽  
...  

: 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.


2012 ◽  
Vol 2012 ◽  
pp. 1-20 ◽  
Author(s):  
Michael Aviram ◽  
Mira Rosenblat

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.


Author(s):  
Parimalanandhini Duraisamy ◽  
Sangeetha Ravi ◽  
Mahalakshmi Krishnan ◽  
Catherene M. Livya ◽  
Beulaja Manikandan ◽  
...  

: 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.


Biomedicines ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 655
Author(s):  
Hiroyuki Itabe ◽  
Naoko Sawada ◽  
Tomohiko Makiyama ◽  
Takashi Obama

Oxidative modification of lipoproteins is implicated in the occurrence and development of atherosclerotic lesions. Earlier studies have elucidated on the mechanisms of foam cell formation and lipid accumulation in these lesions, which is mediated by scavenger receptor-mediated endocytosis of oxidized low-density lipoprotein (oxLDL). Mounting clinical evidence has supported the involvement of oxLDL in cardiovascular diseases. High-density lipoprotein (HDL) is known as anti-atherogenic; however, recent studies have shown circulating oxidized HDL (oxHDL) is related to cardiovascular diseases. A modified structure of oxLDL, which was increased in the plasma of patients with acute myocardial infarction, was characterized. It had two unique features: (1) a fraction of oxLDL accompanied oxHDL, and (2) apoA1 was heavily modified, while modification of apoB, and the accumulation of oxidized phosphatidylcholine (oxPC) and lysophosphatidylcholine (lysoPC) was less pronounced. When LDL and HDL were present at the same time, oxidized lipoproteins actively interacted with each other, and oxPC and lysoPC were transferred to another lipoprotein particle and enzymatically metabolized rapidly. This brief review provides a novel view on the dynamics of oxLDL and oxHDL in circulation.


2017 ◽  
Vol 37 (suppl_1) ◽  
Author(s):  
Annette E Neele ◽  
Koen H Prange ◽  
Marten A Hoeksema ◽  
Saskia van der Velden ◽  
Tina Lucas ◽  
...  

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.


2017 ◽  
Vol 37 (suppl_1) ◽  
Author(s):  
Catherine A Reardon ◽  
Amulya Lingaraju ◽  
Kelly Q Schoenfelt ◽  
Guolin Zhou ◽  
Ning-Chun Liu ◽  
...  

Type 2 diabetics have a higher risk for atherosclerosis, but the mechanisms underlying the increased risk are poorly understood. Macrophages, which are activated in type 2 diabetes (T2D) and have a role in all stages of atherogenesis, are an attractive link. Our hypothesis is that T2D promotes macrophage dysfunction to promote atherosclerosis. To investigate the relationship between T2D and macrophage dysfunction, we used a proteomics approach to identify dysregulated proteins secreted from peritoneal macrophages in a diet induced mouse model of obesity and insulin resistance in the absence of hypercholesterolemia. Twenty-seven T2D responsive proteins were identified that predict defects in many of the critical functions of macrophages in atherosclerosis (e.g. decreased apoE- cholesterol efflux; decreased MFGE8 – efferocytosis, increased MMP12- matrix degradation). The macrophages from lean and obese mice were not lipid loaded, but the obese macrophages accumulated significantly more cholesterol when exposed to high levels of atherogenic lipoproteins in vitro suggesting that dysregulation of the T2D responsive proteins in diabetic mice render macrophages more susceptible to cholesterol loading. Importantly, many of these same protein changes, which were present in atherosclerotic Ldlr-/- mice with T2D, were normalized when these mice were fed non-diabetogenic hypercholesterolemic diets. Thus, foam cell formation in the presence and absence of T2D produces distinct effects on macrophage protein levels, and hence function. Further, we identify IFNγ as a mediator of the T2D responsive protein dysfunction. IFNγ, but not other cytokines, insulin or glucose, promote the T2D responsive protein dysregulation and increased susceptibility to cholesterol accumulation in vitro and the dysregulation is not observed in macrophage foam cells obtained from obese, diabetic IFNγ receptor 1 knockout animals. We also demonstrate that IFNγ can target these proteins in arterial wall macrophages in vivo . These studies suggest that IFNγ is an important mediator of macrophage dysfunction in T2D that may contribute to the enhanced cardiovascular risk in these patients.


Endocrinology ◽  
2007 ◽  
Vol 148 (3) ◽  
pp. 1009-1018 ◽  
Author(s):  
Amélie Rodrigue-Way ◽  
Annie Demers ◽  
Huy Ong ◽  
André Tremblay

Whereas the uptake of oxidized lipoproteins by scavenger receptor CD36 in macrophages has been associated with foam cell formation and atherogenesis, little is known about the role of CD36 in regulating lipid metabolism in adipocytes. Here we report that treatment of 3T3-L1 adipocytes with hexarelin, a GH-releasing peptide that interacts with CD36, resulted in a depletion of intracellular lipid content with no significant change in CD36 expression. Microarray analysis revealed an increased pattern in several genes involved in fatty acid mobilization toward the mitochondrial oxidative phosphorylation process in response to hexarelin. Interestingly, many of these up-regulated genes are known targets of peroxisomal proliferator-activated receptor (PPAR)-γ, such as FATP, CPT-1, and F1-ATPase, suggesting that adipocyte response to hexarelin may involve PPARγ activation. Expression studies also indicate an increase in thermogenic markers PPARγ coactivator 1α and uncoupling protein-1, which are normally expressed in brown adipocytes. Electron microscopy of hexarelin-treated 3T3-L1 adipocytes showed an intense and highly organized cristae formation that spans the entire width of mitochondria, compared with untreated cells, and cytochrome c oxidase activity was enhanced by hexarelin, two features characteristic of highly oxidative tissues. A similar mitochondrial phenotype was detected in epididymal white fat of mice treated with hexarelin, along with an increased expression of thermogenic markers that was lost in treated CD36-null mice, suggesting that the ability of hexarelin to promote a brown fat-like phenotype also occurs in vivo and is dependent on CD36. These results provide a potential role for CD36 to impact the overall metabolic activity of fat usage and mitochondrial biogenesis in adipocytes.


2015 ◽  
Vol 241 (1) ◽  
pp. e81-e82 ◽  
Author(s):  
A. Newby ◽  
A. Thomas

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