TNFAIP1 promotes macrophage lipid accumulation and accelerates the development of atherosclerosis through the LEENE/FoxO1/ABCA1 pathway.

Macrophage lipid accumulation is a critical contributor to foam cell formation and atherosclerosis. Tumor necrosis factor-α-induced protein 1 (TNFAIP1) is closely associated with cardiovascular disease. However, its role and molecular mechanisms in atherogenesis remain unclear. TNFAIP1 was knocked down in THP-1 macrophage-derived foam cells and apolipoprotein-deficient (apoE-/-) mice using lentiviral vector. The expression of lncRNA enhancing endothelial nitric oxide synthase expression (LEENE), Forkhead box O1 (FoxO1) and ATP binding cassette transporter A1 (ABCA1) was evaluated by qRT-PCR and/or western blot. Lipid accumulation in macrophage was assessed by high-performance liquid chromatography and Oil red O staining. RNA immunoprecipitation and RNA pull-down assay were performed to verify the interaction between LEENE and FoxO1 protein. Atherosclerotic lesions were analyzed using HE, Oil red O and Masson staining. Our results showed that TNFAIP1 was significantly increased in THP-1 macrophages loaded with oxidized low-density lipoprotein. Knockdown of TNFAIP1 enhanced LEENE expression, promoted the direct interaction of LEENE with FoxO1 protein, stimulated FoxO1 protein degradation through the proteasome pathway, induced ABCA1 transcription, and finally suppressed lipid accumulation in THP-1 macrophage-derived foam cells. TNFAIP1 knockdown also up-regulated ABCA1 expression, improved plasma lipid profiles, enhanced the efficiency of reverse cholesterol transport and attenuated lesion area in apoE-/- mice. Taken together, these results provide the first direct evidence that TNFAIP1 aggravates atherosclerosis by promoting macrophage lipid accumulation via the LEENE/FoxO1/ABCA1 signaling pathway. TNFAIP1 may represent a promising therapeutic target for atherosclerotic cardiovascular disease.

Asprosin inhibits macrophage lipid accumulation and reduces atherosclerotic burden by up-regulating ABCA1 and ABCG1 expression via the p38/Elk-1 pathway.

BACKGROUND: Asprosin, a newly discovered adipokine, is a C-terminal cleavage product of profibrillin. Asprosin has been reported to participate in lipid metabolism and cardiovascular disease, but its role in atherogenesis remains elusive. METHODS: Asprosin was overexpressed in THP-1 macrophage-derived foam cells and apoE-/- mice using the lentiviral vector. The expression of relevant molecules was determined by qRT-PCR and/or western blot. The intracellular lipid accumulation was evaluated by high-performance liquid chromatography and Oil red O staining. HE and Oil red O staining was employed to assess plaque burden in vivo. Reverse cholesterol transport (RCT) efficiency was measured using [3H]-labeled cholesterol. RESULTS: Exposure of THP-1 macrophages to oxidized low-density lipoprotein down-regulated asprosin expression. Lentivirus-mediated overexpression of asprosin promoted cholesterol efflux and inhibited lipid accumulation in THP-1 macrophage-derived foam cells. Mechanistic analysis revealed that asprosin overexpression activated p38 and stimulated the phosphorylation of ETS-like transcription factor (Elk-1) at Ser383, leading to Elk-1 nuclear translocation and the transcriptional activation of ATP binding cassette transporters A1 (ABCA1) and ABCG1. Injection of lentiviral vector expressing asprosin diminished atherosclerotic lesion area, increased plaque stability, improved plasma lipid profiles and facilitated RCT in apoE-/- mice. Asprosin overexpression also increased the phosphorylation of p38 and Elk-1 as well as up-regulated the expression of ABCA1 and ABCG1 in the aortas. CONCLUSION: Asprosin inhibits lipid accumulation in macrophages and decreases atherosclerotic burden in apoE-/- mice by up-regulating ABCA1 and ABCG1 expression via activation of the p38/Elk-1 signaling pathway.

C1q Tumor Necrosis Factor-Related Protein 1: A Promising Therapeutic Target for Atherosclerosis.

ABSTRACT: Atherosclerosis serves as the pathological basis of most cardiovascular and cerebrovascular diseases. C1q tumor necrosis factor-related protein 1 (CTRP1) is a 35-kDa glycoprotein synthesized by various tissues and cells, such as adipose tissue and macrophages. As an adiponectin paralog, CTRP1 signals through adiponectin receptor 1 and participates in a variety of pathophysiological processes. Circulating CTRP1 levels are significantly increased in patients with coronary artery disease. Importantly, CTRP1 was shown to accelerate the development of atherosclerosis by promoting vascular inflammation, macrophage foam cell formation, and endothelial barrier dysfunction. This review focused on recent advances regarding the role of CTRP1 in atherogenesis with an emphasis on its potential as a novel biomarker and a promising therapeutic target for atherosclerosis-related diseases.

Midkine: A multifaceted driver of atherosclerosis.

Atherosclerosis constitutes the pathological basis of life-threatening events, including heart attack and stroke. Midkine is a heparin-binding growth factor and forms a small protein family with pleiotrophin. Under inflammatory or hypoxic conditions, midkine expression is up-regulated. Upon binding to its receptors, midkine can activate multiple signal pathways to regulate cell survival and migration, epithelial-to-mesenchymal transition, and oncogenesis. Circulating midkine levels are significantly increased in patients with essential hypertension, obesity or severe peripheral artery disease. Importantly, midkine exerts a proatherogenic effect by altering multiple pathophysiological processes involving atherogenesis, including macrophage lipid accumulation, vascular inflammation, neointima formation, insulin resistance and macrophage apoptosis. Midkine represents a potential therapeutic target for atherosclerosis-associated diseases. This review described the structure characteristics, expression patterns and signal transduction pathways of midkine with an emphasis on its role in atherosclerosis.

CTRP12 ameliorates atherosclerosis by promoting cholesterol efflux and inhibiting inflammatory response via the miR-155-5p/LXRα pathway.

C1q tumor necrosis factor-related protein 12 (CTRP12), a conserved paralog of adiponectin, is closely associated with cardiovascular disease. However, little is known about its role in atherogenesis. The aim of this study was to examine the influence of CTRP12 on atherosclerosis and explore the underlying mechanisms. Our results showed that lentivirus-mediated CTRP12 overexpression inhibited lipid accumulation and inflammatory response in lipid-laden macrophages. Mechanistically, CTRP12 decreased miR-155-5p levels and then increased its target gene liver X receptor α (LXRα) expression, which increased ATP binding cassette transporter A1 (ABCA1)- and ABCG1-dependent cholesterol efflux and promoted macrophage polarization to the M2 phenotype. Injection of lentiviral vector expressing CTRP12 decreased atherosclerotic lesion area, elevated plasma high-density lipoprotein cholesterol levels, promoted reverse cholesterol transport (RCT), and alleviated inflammatory response in apolipoprotein E-deficient (apoE-/-) mice fed a Western diet. Similar to the findings of in vitro experiments, CTRP12 overexpression diminished miR-155-5p levels but increased LXRα, ABCA1, and ABCG1 expression in the aortas of apoE-/- mice. Taken together, these results suggest that CTRP12 protects against atherosclerosis by enhancing RCT efficiency and mitigating vascular inflammation via the miR-155-5p/LXRα pathway. Stimulating CTRP12 production could be a novel approach for reducing atherosclerosis.

The antiatherogenic function of kallistatin and its potential mechanism.

Atherosclerosis is the pathological basis of most cardiovascular diseases, the leading cause of morbidity and mortality worldwide. Kallistatin, originally discovered in human serum, is a tissue-kallikrein-binding protein and a unique serine proteinase inhibitor. Upon binding to its receptor integrin ß3, lipoprotein receptor-related protein 6, nucleolin, or Krüppel-like factor 4, kallistatin can modulate various signaling pathways and affect multiple biological processes, including angiogenesis, inflammatory response, oxidative stress, and tumor growth. Circulating kallistatin levels are significantly decreased in patients with coronary artery disease and show an inverse correlation with its severity. Importantly, both in vitro and in vivo experiments have demonstrated that kallistatin reduces atherosclerosis by inhibiting vascular inflammation, antagonizing endothelial dysfunction, and improving lipid metabolism. Thus, kallistatin may be a novel biomarker and a promising therapeutic target for atherosclerosis-related diseases. In this review, we focus on the antiatherogenic function of kallistatin and its potential mechanism.