RP5-833A20.1/miR-382-5p/NFIA-dependent signal transduction pathway contributes to the regulation of cholesterol homeostasis and inflammatory reaction.

OBJECTIVE: Cardiovascular disease caused by atherosclerosis is the number one cause of death in Western countries and threatens to become the major cause of morbidity and mortality worldwide. Long noncoding RNAs are emerging as new players in gene regulation, but how long noncoding RNAs operate in the development of atherosclerosis remains unclear. APPROACH AND RESULTS: Using microarray analysis, we found that long noncoding RNA RP5-833A20.1 expression was upregulated, whereas nuclear factor IA (NFIA) expression was downregulated in human acute monocytic leukemia macrophage-derived foam cells. Moreover, we showed that long noncoding RNA RP5-833A20.1 may decreases NFIA expression by inducing hsa-miR-382-5p expression in vitro. We found that the RP5-833A20.1/hsa-miR-382-5p/NFIA pathway is essential to the regulation of cholesterol homeostasis and inflammatory responses in human acute monocytic leukemia macrophages. Lentivirus-mediated NFIA overexpression increased high-density lipoprotein cholesterol circulation, reduced low-density lipoprotein cholesterol, and very-low-density lipoprotein cholesterol circulation, decreased circulation of inflammatory cytokines, including interleukin-1ß, interleukin-6, tumor necrosis factor-α, and C-reactive protein, enhanced reverse cholesterol transport, and promoted regression of atherosclerosis in apolipoprotein E-deficient mice. CONCLUSIONS: Our findings indicated that the RP5-833A20.1/miR-382-5p/NFIA pathway was essential to the regulation of cholesterol homeostasis and inflammatory reactions and suggested that NFIA may represent a therapeutic target to ameliorate cardiovascular disease.

Ox-LDL upregulates CRP expression through the IGF2 pathway in THP-1 macrophages.

C-reactive protein (CRP) is an acute-phase reactant protein that not only plays a predictive role in determining atherogenesis risk but also represents an active participant in atherogenesis onset and progression. Moreover, an increasing number of studies have reported that oxidized low-density lipoprotein (Ox-LDL) plays a significant role in the initiation and progression of atherosclerosis. However, the effect and underlying mechanism of Ox-LDL on CRP expression remains unclear. THP-1 macrophages were treated with 0, 25, 50, or 100 µg/mL of Ox-LDL for 48 h, or 50 µg/mL of Ox-LDL for 0, 12, 24, and 48 h, respectively. Messenger RNA (mRNA) and protein levels were measured by real-time quantitative PCR and Western blot analysis, respectively. We found that Ox-LDL markedly increased insulin-like growth factor 2 (IGF2) and CRP mRNA and protein levels in a dose- and time-dependent manner in THP-1 macrophages. Treatment with Ox-LDL increased CRP protein expression, and this effect was completely abolished by siRNA-mediated silencing of IGF2 in THP-1 macrophages. Moreover, treatment with pcDNA3.1-IGF2 significantly enhanced CRP protein expression in Ox-LDL-stimulated THP-1 macrophages. CRP expression is upregulated by Ox-LDL through the IGF2 pathway in THP-1 macrophages.

An agomir of miR-144-3p accelerates plaque formation through impairing reverse cholesterol transport and promoting pro-inflammatory cytokine production.

AIMS: ATP-binding cassette transporter A1 (ABCA1) mediates the efflux of cholesterol and phospholipids to lipid-poor apolipoproteins, which then form nascent HDL, a key step in the mechanism of reverse cholesterol transport (RCT). While a series of microRNAs (miRNAs) have been identified as potent post-transcriptional regulators of lipid metabolism, their effects on ABCA1 function and associated mechanisms remain unclear. METHODS AND RESULTS: ABCA1 was identified as a potential target of miR-144-3p, based on the results of bioinformatic analysis and the luciferase reporter assay, and downregulated after transfection of cells with miR-144-3p mimics, as observed with real-time PCR and western blot. Moreover, miR-144-3p mimics (agomir) enhanced the expression of inflammatory factors, including IL-1ß, IL-6 and TNF-α, in vivo and in vitro, inhibited cholesterol efflux in THP-1 macrophage-derived foam cells, decreased HDL-C circulation and impaired RCT in vivo, resulting in accelerated pathological progression of atherosclerosis in apoE-/- mice. Clinical studies additionally revealed a positive correlation of circulating miR-144-3p with serum CK, CK-MB, LDH and AST in subjects with AMI. CONCLUSIONS: Our findings clearly indicate that miR-144-3p is essential for the regulation of cholesterol homeostasis and inflammatory reactions, supporting its utility as a potential therapeutic target of atherosclerosis and a promising diagnostic biomarker of AMI.

Dihydrocapsaicin down-regulates apoM expression through inhibiting Foxa2 expression and enhancing LXRα expression in HepG2 cells.

BACKGROUND: Apolipoprotein M (apoM), as a novel apolipoprotein which is mainly expressed in liver and kidney tissues, is associated with development and progression of atherosclerosis and diabetes. Our group have recently shown that Dihydrocapsaicin(DHC)can significantly decrease atherosclerotic plaque formation in apoE-/- mice. However, the effect and possible mechanism of DHC on apoM expression remain unclear. METHODS: HepG2 cells were treated with 0 µM, 25 µM, 50 µM and 100 µM DHC for 24 h or were treated with 100 µM DHC for 0, 6, 12, and 24 h, respectively. The mRNA levels and protein levels were measured by real-time quantitative PCR and western blot analysis, respectively. RESULTS: We found that DHC markedly decreased expression of apoM at both mRNA and protein level in HepG2 cells in a dose-dependent and time-dependent manner. Expression of Foxa2 was decreased while expression of LXRα was increased by DHC treatment in HepG2 cells. In addittion, overexpression of Foxa2 markedly compensated the inhibition effect induced by DHC on apoM expression. LXRα small interfering RNA significantly abolished the inhibition effect which induced by DHC on apoM expression. The liver of C57BL/6 mice treated with DHC had significantly lower expression of apoM. Furthermore, the liver had lower expression of Foxa2 while had higher expression of LXRα. CONCLUSIONS: DHC could down-regulate apoM expression through inhibiting Foxa2 expression and enhancing LXRα expression in HepG2 cells.

A lincRNA-DYNLRB2-2/GPR119/GLP-1R/ABCA1-dependent signal transduction pathway is essential for the regulation of cholesterol homeostasis.

Accumulated evidence shows that G protein-coupled receptor 119 (GPR119) plays a key role in glucose and lipid metabolism. Here, we explored the effect of GPR119 on cholesterol metabolism and inflammation in THP-1 macrophages and atherosclerotic plaque progression in apoE(-/-) mice. We found that oxidized LDL (Ox-LDL) significantly induced long intervening noncoding RNA (lincRNA)-DYNLRB2-2 expression, resulting in the upregulation of GPR119 and ABCA1 expression through the glucagon-like peptide 1 receptor signaling pathway. GPR119 significantly decreased cellular cholesterol content and increased apoA-I-mediated cholesterol efflux in THP-1 macrophage-derived foam cells. In vivo, apoE(-/-) mice were randomly divided into two groups and infected with lentivirus (LV)-Mock or LV-GPR119 for 8 weeks. GPR119-treated mice showed decreased liver lipid content and plasma TG, interleukin (IL)-1ß, IL-6, and TNF-α levels, whereas plasma levels of apoA-I were significantly increased. Consistent with this, atherosclerotic lesion development was significantly inhibited by infection of apoE(-/-) mice with LV-GPR119. Our findings clearly indicate that, Ox-LDL significantly induced lincRNA-DYNLRB2-2 expression, which promoted ABCA1-mediated cholesterol efflux and inhibited inflammation through GPR119 in THP-1 macrophage-derived foam cells. Moreover, GPR119 decreased lipid and serum inflammatory cytokine levels, decreasing atherosclerosis in apoE(-/-) mice. These suggest that GPR119 may be a promising candidate as a therapeutic agent.

Nur77 decreases atherosclerosis progression in apoE(-/-) mice fed a high-fat/high-cholesterol diet.

RATIONALE: It is clear that lipid disorder and inflammation are associated with cardiovascular diseases and underlying atherosclerosis. Nur77 has been shown to be involved in inflammatory response and lipid metabolism. OBJECTIVE: Here, we explored the role of Nur77 in atherosclerotic plaque progression in apoE(-/-) mice fed a high-fat/high cholesterol diet. METHODS AND RESULTS: The Nur77 gene, a nuclear hormone receptor, was highly induced by treatment with Cytosporone B (Csn-B, specific Nur77 agonist), recombinant plasmid over-expressing Nur77 (pcDNA-Nur77), while inhibited by treatment with siRNAs against Nur77 (si-Nur77) in THP-1 macrophage-derived foam cells, HepG2 cells and Caco-2 cells, respectively. In addition, the expression of Nur77 was highly induced by Nur77 agonist Csn-B, lentivirus encoding Nur77 (LV-Nur77), while silenced by lentivirus encoding siRNA against Nur77 (si-Nur77) in apoE(-/-) mice fed a high-fat/high cholesterol diet, respectively. We found that increased expression of Nur77 reduced macrophage-derived foam cells formation and hepatic lipid deposition, downregulated gene levels of inflammatory molecules, adhesion molecules and intestinal lipid absorption, and decreases atherosclerotic plaque formation. CONCLUSION: These observations provide direct evidence that Nur77 is an important nuclear hormone receptor in regulation of atherosclerotic plaque formation and thus represents a promising target for the treatment of atherosclerosis.

[Prevalence and risk factors of asymptomatic intracranial vascular stenosis in patients with essential hypertension].

OBJECTIVE: The aim of the study was to determine the prevalence and the distribution pattern of lesion site of intracranial vascular stenosis and to identify risk factors for the stenosis in patients with essential hypertension. METHODS: A total of 231 consecutive inpatients with essential hypertension were included in this study. Patients with the history of cerebrovascular diseases and relevant neurological symptoms were excluded. Intracranial vascular stenosis (>50% diameter reduction) was detected using CT angiography (CTA). RESULTS: Of 231 patients, 69 (29.87%) had intracranial artery stenosis. The most common stenosis site is middle cerebral artery (43.69%), followed by carotid siphon (20.39%). The stenosis in internal carotid arterial system (78.64%) was more common than in vertebrobasilar arterial system (21.56%, P < 0.05). The patients with intracranial vascular stenosis were older, had longer history of hypertension, higher levels of systolic blood pressure, higher plasma cholesterol, higher LDL-C. Lp (a), higher urinary microalbumin excretion, thicker ventricular septum, and lower levels of HDL-C than the patients without stenosis. Logistic analysis showed that systolic blood pressure (OR 1.650, 95% CI 1.134 - 2.400, P = 0.023), course of hypertension (OR 1.238, 95% CI 1.072 - 1.429, P = 0.006), LDL-C (OR 2.103, 95% CI 1.157 - 3.823, P = 0.014) and type 2 diabetes (OR 2.325, 95% CI 1.161 - 4.341, P = 0.011) were the independent risk factors of asymptomatic intracranial arterial stenosis. CONCLUSIONS: Nearly 30% inpatients with essential hypertension had asymptomatic intracranial artery stenosis. The most common site of stenosis was middle cerebral artery. Hypertension, dyslipidemia and diabetes were risk factors for the development of intracranial arterial stenosis.

[Aldosterone-to-renin ratio threshold for screening primary aldosteronism in Chinese hypertensive patients].

OBJECTIVE: In recent years, the assessment of the plasma aldosterone-to-renin ratio (ARR) has become a most effectively and commonly used method for screening primary aldosteronism from hypertensive patients. It is known that there is a large variance in ARR value between races and ARR is affected by many factors, such as drugs, posture and serum potassium etc. The objective of this study is to establish the threshold of ARR for screening primary aldosteronism in Chinese hypertensive patients. METHODS: A total of 110 hypertensive patients were recruited and divided into essential hypertension group (n=65) and adenoma/hyperplasia group (n=45) according to the adrenal contrast CT scan. Antihypertensive drugs which can affect ARR such as beta-blockers, dihydropyridine calcium channel blockers (CCBs), ACE inhibitors (ACEIs), angiotensin II receptor blockers (ARBs) and clonidine, were withdrawn for at least 2 weeks. Washout period for diuretics including spironolactone were 4 weeks. Non-dihydropyridine calcium channel blockers (slow released verapamil) and/or alpha-blocker (terazosin) are allowed for controlling blood pressure when needed. If the serum potassium value<3.6 mmol/L, an oral potassium supplement was prescribed. After keeping upright position for 2 hours, blood samples were drawn for PRA and PAC measurement between 9:00AM-10:00AM. RESULTS: ARR was 100.00+/-48.65 (14.19-285.16) pg/ml vs ngxml-1xh-1 in patients with essential hypertension and 699.33+/-213.33 (185.8-2150) pg/ml vs ngxml-1xh-1 in patients with adenoma/hyperplasia. ARR value was greater than 240 in 42 out of 45 patients (93.3%) with adenoma/hyperplasia and was less than 240 in 59 out of 65 (90.7%) patients with essential hypertension. We used ARR 240 as the cut-off threshold for screening primary aldosteronism in another 178 hypertensive patients and ARR was greater than 240 in all 15 patients with confirmed primary aldosteronism. CONCLUSION: It is suitable to use upright ARR 240 as a cut-off threshold for screening primary aldosteronism in Chinese hypertensive patients.