A novel mouse model of familial combined hyperlipidemia and atherosclerosis.

Within the context of residual cardiovascular risk in post-statin era, emerging evidence from epidemiologic and human genetic studies have demonstrated that triglyceride (TG)-rich lipoproteins and their remnants are causally related to cardiovascular risk. While, carriers of loss-of-function mutations of ApoC3 have low TG levels and are protected from cardiovascular disease (CVD). Of translational significance, siRNAs/antisense oligonucleotide (ASO) targeting ApoC3 is beneficial for patients with atherosclerotic CVD. Therefore, animal models of atherosclerosis with both hypercholesterolemia and hypertriglyceridemia are important for the discovery of novel therapeutic strategies targeting TG-lowering on top of traditional cholesterol-lowering. In this study, we constructed a novel mouse model of familial combined hyperlipidemia through inserting a human ApoC3 transgene (hApoC3-Tg) into C57BL/6 J mice and injecting a gain-of-function variant of adeno-associated virus-proprotein convertase subtilisin/kexin type 9 (AAV-PCSK9)-D377Y concurrently with high cholesterol diet (HCD) feeding for 16 weeks. In the last 10 weeks, hApoC3-Tg mice were orally treated with a combination of atorvastatin (10 mg·kg-1·d-1) and fenofibrate (100 mg·kg-1·d-1). HCD-treated hApoC3-Tg mice demonstrated elevated levels of serum TG, total cholesterol (TC) and low density lipoprotein-cholesterol (LDL-C). Oral administration of atorvastatin and fenofibrate significantly decreased the plaque sizes of en face aorta, aortic sinus and innominate artery accompanied by improved lipid profile and distribution. In summary, this novel mouse model is of considerable clinical relevance for evaluation of anti-atherosclerotic drugs by targeting both hypercholesterolemia and hypertriglyceridemia.

Empagliflozin and liraglutide ameliorate HFpEF in mice via augmenting the Erbb4 signaling pathway.

Heart failure with preserved ejection fraction (HFpEF) is closely associated with metabolic derangement. Sodium glucose cotransporter-2 inhibitors (SGLT2i) and glucagon-like peptide-1 receptor agonists (GLP-1RA) exert anti-HFpEF effects, but the underlying mechanisms remain unclear. In this study, we explored the anti-HFpEF effects of empagliflozin and liraglutide and the underlying molecular mechanisms in a mouse model of HFpEF. This model was established by high-fat diet (HFD) feeding plus Nω-nitro-L-arginine methyl ester (L-NAME) treatment. The mice were treated with empagliflozin (20 mg·kg-1·d-1, i.g.) or liraglutide (0.3 mg·kg-1·d-1, i.p.) or their combination for 4 weeks. At the end of the experimental protocol, cardiac function was measured using ultrasound, then mice were euthanized and heart, liver, and kidney tissues were collected. Nuclei were isolated from frozen mouse ventricular tissue for single-nucleus RNA-sequencing (snRNA-seq). We showed that administration of empagliflozin or liraglutide alone or in combination significantly improved diastolic function, ameliorated cardiomyocyte hypertrophy and cardiac fibrosis, as well as exercise tolerance but no synergism was observed in the combination group. Furthermore, empagliflozin and/or liraglutide lowered body weight, improved glucose metabolism, lowered blood pressure, and improved liver and kidney function. After the withdrawal of empagliflozin or liraglutide for 1 week, these beneficial effects tended to diminish. The snRNA-seq analysis revealed a subcluster of myocytes, in which Erbb4 expression was down-regulated under HFpEF conditions, and restored by empagliflozin or liraglutide. Pseudo-time trajectory analysis and cell-to-cell communication studies confirmed that the Erbb4 pathway was a prominent pathway essential for both drug actions. In the HFpEF mouse model, both empagliflozin and liraglutide reversed Erbb4 down-regulation. In rat h9c2 cells, we showed that palmitic acid- or high glucose-induced changes in PKCα and/or ERK1/2 phosphorylation at least in part through Erbb4. Collectively, the single-cell atlas reveals the anti-HFpEF mechanism of empagliflozin and liraglutide, suggesting that Erbb4 pathway represents a new therapeutic target for HFpEF. Effects and mechanisms of action of empagliflozin and liraglutide in HFpEF mice. HFpEF was induced with a high-fat diet and L-NAME for 15 weeks, and treatment with empagliflozin and liraglutide improved the HFpEF phenotype. Single nucleus RNA sequencing (snRNA-seq) was used to reveal the underlying mechanism of action of empagliflozin and liraglutide.

Animal models of heart failure with preserved ejection fraction (HFpEF): from metabolic pathobiology to drug discovery.

Heart failure (HF) with preserved ejection fraction (HFpEF) is currently a preeminent challenge for cardiovascular medicine. It has a poor prognosis, increasing mortality, and is escalating in prevalence worldwide. Despite accounting for over 50% of all HF patients, the mechanistic underpinnings driving HFpEF are poorly understood, thus impeding the discovery and development of mechanism-based therapies. HFpEF is a disease syndrome driven by diverse comorbidities, including hypertension, diabetes and obesity, pulmonary hypertension, aging, and atrial fibrillation. There is a lack of high-fidelity animal models that faithfully recapitulate the HFpEF phenotype, owing primarily to the disease heterogeneity, which has hampered our understanding of the complex pathophysiology of HFpEF. This review provides an updated overview of the currently available animal models of HFpEF and discusses their characteristics from the perspective of energy metabolism. Interventional strategies for efficiently utilizing energy substrates in preclinical HFpEF models are also discussed.

Urolithin A promotes atherosclerotic plaque stability by limiting inflammation and hypercholesteremia in Apolipoprotein E-deficient mice.

Urolithin A (UroA), a dietary phytochemical, is produced by gut bacteria from fruits rich in natural polyphenols ellagitannins (ETs). The efficiency of ETs metabolism to UroA in humans depends on gut microbiota. UroA has shown a variety of pharmacological activities. In this study we investigated the effects of UroA on atherosclerotic lesion development and stability. Apolipoprotein E-deficient (ApoE-/-) mice were fed a high-fat and high-cholesterol diet for 3 months to establish atherosclerosis model. Meanwhile the mice were administered UroA (50 mg·kg-1·d-1, i.g.). We showed that UroA administration significantly decreased diet-induced atherosclerotic lesions in brachiocephalic arteries, macrophage content in plaques, expression of endothelial adhesion molecules, intraplaque hemorrhage and size of necrotic core, while increased the expression of smooth muscle actin and the thickness of fibrous cap, implying features of plaque stabilization. The underlying mechanisms were elucidated using TNF-α-stimulated human endothelial cells. Pretreatment with UroA (10, 25, 50 µM) dose-dependently inhibited TNF-α-induced endothelial cell activation and monocyte adhesion. However, the anti-inflammatory effects of UroA in TNF-α-stimulated human umbilical vein endothelial cells (HUVECs) were independent of NF-κB p65 pathway. We conducted RNA-sequencing profiling analysis to identify the differential expression of genes (DEGs) associated with vascular function, inflammatory responses, cell adhesion and thrombosis in UroA-pretreated HUVECs. Human disease enrichment analysis revealed that the DEGs were significantly correlated with cardiovascular diseases. We demonstrated that UroA pretreatment mitigated endothelial inflammation by promoting NO production and decreasing YAP/TAZ protein expression and TEAD transcriptional activity in TNF-α-stimulated HUVECs. On the other hand, we found that UroA administration modulated the transcription and cleavage of lipogenic transcription factors SREBP1/2 in the liver to ameliorate cholesterol metabolism in ApoE-/- mice. This study provides an experimental basis for new dietary therapeutic option to prevent atherosclerosis.

Endothelial dysfunction in COVID-19: an overview of evidence, biomarkers, mechanisms and potential therapies.

The fight against coronavirus disease 2019 (COVID-19) caused by SARS-CoV-2 infection is still raging. However, the pathophysiology of acute and post-acute manifestations of COVID-19 (long COVID-19) is understudied. Endothelial cells are sentinels lining the innermost layer of blood vessel that gatekeep micro- and macro-vascular health by sensing pathogen/danger signals and secreting vasoactive molecules. SARS-CoV-2 infection primarily affects the pulmonary system, but accumulating evidence suggests that it also affects the pan-vasculature in the extrapulmonary systems by directly (via virus infection) or indirectly (via cytokine storm), causing endothelial dysfunction (endotheliitis, endothelialitis and endotheliopathy) and multi-organ injury. Mounting evidence suggests that SARS-CoV-2 infection leads to multiple instances of endothelial dysfunction, including reduced nitric oxide (NO) bioavailability, oxidative stress, endothelial injury, glycocalyx/barrier disruption, hyperpermeability, inflammation/leukocyte adhesion, senescence, endothelial-to-mesenchymal transition (EndoMT), hypercoagulability, thrombosis and many others. Thus, COVID-19 is deemed as a (micro)vascular and endothelial disease. Of translational relevance, several candidate drugs which are endothelial protective have been shown to improve clinical manifestations of COVID-19 patients. The purpose of this review is to provide a latest summary of biomarkers associated with endothelial cell activation in COVID-19 and offer mechanistic insights into the molecular basis of endothelial activation/dysfunction in macro- and micro-vasculature of COVID-19 patients. We envisage further development of cellular models and suitable animal models mimicking endothelial dysfunction aspect of COVID-19 being able to accelerate the discovery of new drugs targeting endothelial dysfunction in pan-vasculature from COVID-19 patients.

Regulation of toll-like receptor (TLR) signaling pathways in atherosclerosis: from mechanisms to targeted therapeutics.

Atherosclerosis, one of the life-threatening cardiovascular diseases (CVDs), has been demonstrated to be a chronic inflammatory disease, and inflammatory and immune processes are involved in the origin and development of the disease. Toll-like receptors (TLRs), a class of pattern recognition receptors that trigger innate immune responses by identifying pathogen-associated molecular patterns (PAMPs) and danger-associated molecular patterns (DAMPs), regulate numerous acute and chronic inflammatory diseases. Recent studies reveal that TLRs have a vital role in the occurrence and development of atherosclerosis, including the initiation of endothelial dysfunction, interaction of various immune cells, and activation of a number of other inflammatory pathways. We herein summarize some other inflammatory signaling pathways, protein molecules, and cellular responses associated with TLRs, such as NLRP3, Nrf2, PCSK9, autophagy, pyroptosis and necroptosis, which are also involved in the development of AS. Targeting TLRs and their regulated inflammatory events could be a promising new strategy for the treatment of atherosclerotic CVDs. Novel drugs that exert therapeutic effects on AS through TLRs and their related pathways are increasingly being developed. In this article, we comprehensively review the current knowledge of TLR signaling pathways in atherosclerosis and actively seek potential therapeutic strategies using TLRs as a breakthrough point in the prevention and therapy of atherosclerosis.

Transcription factor 21 accelerates vascular calcification in mice by activating the IL-6/STAT3 signaling pathway and the interplay between VSMCs and ECs.

Vascular calcification is caused by the deposition of calcium salts in the intimal or tunica media layer of the aorta, which increases the risk of cardiovascular events and all-cause mortality. However, the mechanisms underlying vascular calcification are not fully clarified. Recently it has been shown that transcription factor 21 (TCF21) is highly expressed in human and mouse atherosclerotic plaques. In this study we investigated the role of TCF21 in vascular calcification and the underlying mechanisms. In carotid artery atherosclerotic plaques collected from 6 patients, we found that TCF21 expression was upregulated in calcific areas. We further demonstrated TCF21 expression was increased in an in vitro vascular smooth muscle cell (VSMC) osteogenesis model. TCF21 overexpression promoted osteogenic differentiation of VSMC, whereas TCF21 knockdown in VSMC attenuated the calcification. Similar results were observed in ex vivo mouse thoracic aorta rings. Previous reports showed that TCF21 bound to myocardin (MYOCD) to inhibit the transcriptional activity of serum response factor (SRF)-MYOCD complex. We found that SRF overexpression significantly attenuated TCF21-induced VSMC and aortic ring calcification. Overexpression of SRF, but not MYOCD, reversed TCF21-inhibited expression of contractile genes SMA and SM22. More importantly, under high inorganic phosphate (3 mM) condition, SRF overexpression reduced TCF21-induced expression of calcification-related genes (BMP2 and RUNX2) as well as vascular calcification. Moreover, TCF21 overexpression enhanced IL-6 expression and downstream STAT3 activation to facilitate vascular calcification. Both LPS and STAT3 could induce TCF21 expression, suggesting that the inflammation and TCF21 might form a positive feedback loop to amplify the activation of IL-6/STAT3 signaling pathway. On the other hand, TCF21 induced production of inflammatory cytokines IL-1ß and IL-6 in endothelial cells (ECs) to promote VSMC osteogenesis. In EC-specific TCF21 knockout (TCF21ECKO) mice, VD3 and nicotine-induced vascular calcification was significantly reduced. Our results suggest that TCF21 aggravates vascular calcification by activating IL-6/STAT3 signaling and interplay between VSMC and EC, which provides new insights into the pathogenesis of vascular calcification. TCF21 enhances vascular calcification by activating the IL-6-STAT3 signaling pathway. TCF21 inhibition may be a new potential therapeutic strategy for the prevention and treatment of vascular calcification.

Therapeutic potential of colchicine in cardiovascular medicine: a pharmacological review.

Colchicine is an ancient herbal drug derived from Colchicum autumnale. It was first used to treat familial Mediterranean fever and gout. Based on its unique efficacy as an anti-inflammatory agent, colchicine has been used in the therapy of cardiovascular diseases including coronary artery disease, atherosclerosis, recurrent pericarditis, vascular restenosis, heart failure, and myocardial infarction. More recently, colchicine has also shown therapeutic efficacy in alleviating cardiovascular complications of COVID-19. COLCOT and LoDoCo2 are two milestone clinical trials that confirm the curative effect of long-term administration of colchicine in reducing the incidence of cardiovascular events in patients with coronary artery disease. There is growing interest in studying the anti-inflammatory mechanisms of colchicine. The anti-inflammatory action of colchicine is mediated mainly through inhibiting the assembly of microtubules. At the cellular level, colchicine inhibits the following: (1) endothelial cell dysfunction and inflammation; (2) smooth muscle cell proliferation and migration; (3) macrophage chemotaxis, migration, and adhesion; (4) platelet activation. At the molecular level, colchicine reduces proinflammatory cytokine release and inhibits NF-κB signaling and NLRP3 inflammasome activation. In this review, we summarize the current clinical trials with proven curative effect of colchicine in treating cardiovascular diseases. We also systematically discuss the mechanisms of colchicine action in cardiovascular therapeutics. Altogether, colchicine, a bioactive constituent from an ancient medicinal herb, exerts unique anti-inflammatory effects and prominent cardiovascular actions, and will charter a new page in cardiovascular medicine.

Rutaecarpine: A promising cardiovascular protective alkaloid from Evodia rutaecarpa (Wu Zhu Yu).

Rutaecarpine is a bioactive alkaloid isolated from Evodia rutaecarpa (Wu Zhu Yu, Family: Rutaceae), a versatile medicinal herb which is clinically used to treat headache, abdominal pain, postpartum hemorrhage, dysentery, and amenorrhea in China. As one of the most representative indolopyridoquinazoline alkaloids of Evodia rutaecarpa, rutaecarpine has broad pharmacological actions in treating various cardiovascular, cerebrovascular, and metabolic diseases. The cardiovascular actions of rutaecarpine have aroused intense research interest due to its purported inotropic and chronotropic, vasodilatory, anti-platelet activation, anti-oxidant, anti-inflammatory, and lipid-lowering effects. Biochemical and pharmacological studies have illustrated the molecular targets of rutaecarpine, such as TRPV1, CGRP, AMPK, ABCA1, and ß1-AR. Furthermore, several rutaecarpine derivatives (such as bromorutaecarpine and fluororutaecarpine) have been shown to possess cardioprotective and vasculoprotective effects with improved safety profile. Hereby, we provide a systematic overview of pharmacological actions, toxicological effects, and molecular targets of rutaecarpine in cardiovascular disease prevention/treatment, aiming to exploit the therapeutic potential of rutaecarpine and its derivatives in treating cardiovascular diseases.

Danhong injection in cardiovascular and cerebrovascular diseases: Pharmacological actions, molecular mechanisms, and therapeutic potential.

Cardiovascular and cerebrovascular diseases are the main cause of mortality worldwide, currently with less than optimum therapeutic options. Danhong injection (DHI) is a medicinal preparation based on two eminent Chinese herbal medicines, Salviae Miltiorrhizae (Dan Shen; family: Lamiaceae) and Flos Carthami (Hong Hua; family: Compositae/Asteraceae). DHI has been mainly used in the clinical therapy of cardiovascular (such as acute coronary syndrome and angina pectoris) and cerebrovascular diseases (such as stroke) in China for many years. The pharmacological properties of DHI include anti-inflammatory, anti-oxidant, anti-coagulatory, hypolipidemic, anti-apoptotic, vasodilatory, and angiogenesis-promoting actions. DHI offers a safe and effective therapeutic agent against cardiovascular and cerebrovascular diseases by modulating multiple disease-relevant signaling pathways and molecular targets. Herein, we provide a comprehensive review of the phytochemistry, therapeutic effects, molecular mechanisms, and adverse reactions of DHI in cardiovascular and cerebrovascular diseases. We also highlight the latest pharmacological advances and therapeutic potential of this promising herb-derived cardiovascular drug preparation.

Salvia miltiorrhizaBurge (Danshen): a golden herbal medicine in cardiovascular therapeutics.

Salvia miltiorrhiza Burge (Danshen) is an eminent medicinal herb that possesses broad cardiovascular and cerebrovascular protective actions and has been used in Asian countries for many centuries. Accumulating evidence suggests that Danshen and its components prevent vascular diseases, in particular, atherosclerosis and cardiac diseases, including myocardial infarction, myocardial ischemia/reperfusion injury, arrhythmia, cardiac hypertrophy and cardiac fibrosis. The published literature indicates that lipophilic constituents (tanshinone I, tanshinone IIa, tanshinone IIb, cryptotanshinone, dihydrotanshinone, etc) as well as hydrophilic constituents (danshensu, salvianolic acid A and B, protocatechuic aldehyde, etc) contribute to the cardiovascular protective actions of Danshen, suggesting a potential synergism among these constituents. Herein, we provide a systematic up-to-date review on the cardiovascular actions and therapeutic potential of major pharmacologically active constituents of Danshen. These bioactive compounds will serve as excellent drug candidates in small-molecule cardiovascular drug discovery. This article also provides a scientific rationale for understanding the traditional use of Danshen in cardiovascular therapeutics.

EEN regulates the proliferation and survival of multiple myeloma cells by potentiating IGF-1 secretion.

The molecular mechanisms of multiple myeloma are not well defined. EEN is an endocytosis-regulating molecule. Here we report that EEN regulates the proliferation and survival of multiple myeloma cells, by regulating IGF-1 secretion. In the present study, we observed that EEN expression paralleled with cell proliferation, EEN accelerated cell proliferation, facilitated cell cycle transition from G1 to S phase by regulating cyclin-dependent kinases (CDKs) pathway, and delayed cell apoptosis via Bcl2/Bax-mitochondrial pathway. Mechanistically, we found that EEN was indispensable for insulin-like growth factor-1 (IGF-1) secretion and the activation of protein kinase B-mammalian target of rapamycin (Akt-mTOR) pathway. Exogenous IGF-1 overcame the phenotype of EEN depletion, while IGF-1 neutralization overcame that of EEN over-expression. Collectively, these data suggest that EEN may play a pivotal role in excessive cell proliferation and insufficient cell apoptosis of bone marrow plasma cells in multiple myeloma. Therefore, EEN may represent a potential diagnostic marker or therapeutic target for multiple myeloma.

BIG1, a brefeldin A-inhibited guanine nucleotide-exchange protein modulates ATP-binding cassette transporter A-1 trafficking and function.

OBJECTIVE: Cell-surface localization and intracellular trafficking are essential for the function of ATP-binding cassette transporter A-1 (ABCA1). However, regulation of these activities is still largely unknown. Brefeldin A, an uncompetitive inhibitor of brefeldin A-inhibited guanine nucleotide-exchange proteins (BIGs), disturbs the intracellular distribution of ABCA1, and thus inhibits cholesterol efflux. This study aimed to define the possible roles of BIGs in regulating ABCA1 trafficking and cholesterol efflux, and further to explore the potential mechanism. METHODS AND RESULTS: By vesicle immunoprecipitation, we found that BIG1 was associated with ABCA1 in vesicles preparation from rat liver. BIG1 depletion reduced surface ABCA1 on HepG2 cells, and inhibited by 60% cholesterol release. In contrast, BIG1 overexpression increased surface ABCA1 and cholesterol secretion. With partial restoration of BIG1 through overexpression in BIG1-depleted cells, surface ABCA1 was also restored. Biotinylation and glutathione cleavage revealed that BIG1 small interfering RNA dramatically decreased the internalization and recycling of ABCA1. This novel function of BIG1 was dependent on the guanine nucleotide-exchange activity and achieved through activation of ADP-ribosylation factor 1. CONCLUSIONS: BIG1, through its ability to activate ADP-ribosylation factor 1, regulates cell-surface levels and function of ABCA1, indicating a transcription-independent mechanism for controlling ABCA1 action.

Icariin derivative inhibits inflammation through suppression of p38 mitogen-activated protein kinase and nuclear factor-kappaB pathways.

In this study we investigated the anti-inflammatory effects of an icariin derivative (3,5-dihydroxy-4'-methoxy-6'',6''-dimethy1-4'',5''-dihydropyrano[2'',3'':7,8]-flavone). We found that this icariin derivative inhibits tumor necrosis factor-alpha (TNF-alpha) production, inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) mRNA expression, and protein expression in lipopolysaccharide (LPS) stimulated RAW264.7 macrophages. It also alleviates paw edema induced by carrageenan in mice. To clarify the molecular mechanisms underlying these anti-inflammatory effects, we examined the effects of this compound on the phosphorylation of mitogen-activated protein kinase (MAPK), phosphorylation of inhibitory kappaBalpha (IkappaBalpha), and nuclear translocation of p65 subunit of nuclear factor (NF)-kappaB, and found it suppresses the activation of p38 MAPK and inhibits translocation of NF-kappaB p65 to the nucleus through decreasing the phosphorylation of IkappaBalpha. As a result of these properties, this icariin derivative can be considered as a potential drug for inflammatory diseases.

Targeting LOX-1 in atherosclerosis and vasculopathy: current knowledge and future perspectives.

LOX-1 (lectin-like oxidized low-density lipoprotein receptor-1; also known as OLR1) is the dominant receptor that recognizes and internalizes oxidized low-density lipoproteins (ox-LDLs) in endothelial cells. Several genetic variants of LOX-1 are associated with the risk and severity of coronary artery disease. The LOX-1-ox-LDL interaction induces endothelial dysfunction, leukocyte adhesion, macrophage-derived foam cell formation, smooth muscle cell proliferation and migration, and platelet activation. LOX-1 activation eventually leads to the rupture of atherosclerotic plaques and acute cardiovascular events. In addition, LOX-1 can be cleaved to generate soluble LOX-1 (sLOX-1), which is a useful diagnostic and prognostic marker for atherosclerosis-related diseases in human patients. Of therapeutic relevance, several natural products and clinically used drugs have emerged as LOX-1 inhibitors that have antiatherosclerotic actions. We hereby provide an updated overview of role of LOX-1 in atherosclerosis and associated vascular diseases, with an aim to highlighting the potential of LOX-1 as a novel theranostic tool for cardiovascular disease prevention and treatment.

Cryptotanshinone suppressed inflammatory cytokines secretion in RAW264.7 macrophages through inhibition of the NF-κB and MAPK signaling pathways.

Cryptotanshinone (CTS), a major constituent extracted from the medicinal herb Salvia miltiorrhiza Bunge, has well-documented antioxidative and anti-inflammatory effects. In the present study, the pharmacological effects and underlying molecular mechanisms of CTS on lipopolysaccharide (LPS)-induced inflammatory responses were investigated. By enzyme-linked immunosorbent assay, we observed that CTS reduced significantly the production of proinflammatory mediators (tumor necrosis factor-α and interleukin-6) induced by LPS in murine macrophage-like RAW264.7 cells. Mechanistically, CTS inhibited markedly the phosphorylation of mitogen-activated protein kinases (MAPKs), including ERK1/2, p38MAPK, and JNK, which are crucially involved in regulation of proinflammatory mediator secretion. Moreover, immunofluorescence and western blot analysis indicated that CTS abolished completely LPS-triggered nuclear factor-κB (NF-κB) activation. Taken together, these data implied that NF-κB and MAPKs might be the potential molecular targets for clarifying the protective effects of CTS on LPS-induced inflammatory cytokine production in macrophages.

Tanshinone IIA attenuates atherosclerosis in ApoE(-/-) mice through down-regulation of scavenger receptor expression.

This study is designed to investigate the protection of tanshinone IIA (TSIIA) against atherosclerosis in apolipoprotein E deficient (ApoE(-/-)) mice and to explore the mechanisms by focusing on the expressions of scavenger receptors, scavenger receptor-A (SR-A) and CD36. The in vivo study demonstrated that TSIIA (10-90mg/kg) inhibited the atherosclerotic lesions, down-regulated the CD68 protein expression in lesion and decreased the contents of cholesterol in aortas of ApoE(-/-) mice. In addition, TSIIA reduced the serum levels of oxidized LDL (oxLDL) and down-regulated the mRNA expression of CD36, SR-A and peroxisome proliferator-activated receptor gamma (PPARγ) in aortas. The in vitro study showed that TSIIA (0.1-10µM) decreased cholesterol level and DiI-oxLDL uptake in mouse peritoneal macrophages treated with oxLDL (50µg/ml). In addition, TSIIA down-regulated the mRNA and protein expression of CD36 but not that of SR-A in oxLDL treated macrophages. TSIIA also down-regulated the mRNA expression of PPARγ in oxLDL treated macrophages. Furthermore, TSIIA reduced the mRNA expression of CD36 in macrophages treated with PPARγ agonist 15d-PGJ(2) (2µM) or troglitazone (50µM), whereas both 15d-PGJ(2) (0.5-1.5µM) and troglitazone (5-20µM) dose-dependently abolished the down-regulation of CD36 expression by TSIIA in oxLDL treated macrophages. These results suggest that TSIIA attenuates the atherosclerotic lesion in ApoE(-/-) mice, which might be attributed to the properties of both anti-oxidation and down-regulation of scavenger receptors. Furthermore, antagonism of PPARγ might be involved in the down-regulation of CD36 by TSIIA.

Tanshinone II-A attenuates cardiac fibrosis and modulates collagen metabolism in rats with renovascular hypertension.

The adaptive changes that develop in the pressure-overloaded left ventricular myocardium include cardiac hypertrophy and interstitial fibrosis. The objectives of the present study were to evaluate the effects of Tanshinone II-A, a bioactive diterpene quinone isolated from Danshen, on cardiac fibrosis and collagen metabolism in rats with renovascular hypertension. Male Sprague-Dawley rats were subjected to two-kidney two-clip (2K2C) or sham operation (sham) and treated with Valsartan (Val, 26.7 mg/kg/d), Tanshinone II-A (Tsn, 70, 35 mg/kg/d) or vehicle. Six weeks later, systolic blood pressure (BP), LV weight, collagen abundance, cardiac function parameters, hydroxyproline content and mRNA levels of matrix metalloproteinase (MMP)-2, MMP-9, tissue inhibitor of metalloproteinase (TIMP)-1 and TIMP-2 were evaluated. Both high-dose (Tsn-H, 70 mg/kg/d) and low-dose (Tsn-L, 35 mg/kg/d) of Tsn failed to attenuate 2K2C-induced BP elevation but significantly attenuated the attendant interstitial fibrosis. Val suppressed elevations of BP and left ventricular systolic pressure (LVSP) in 2K2C rats. Val and Tsn-H exerted comparable suppressive effects on the gene expression of MMP-9 and TIMP-1, while Val decreased the MMP-2 mRNA level without affecting the transcript levels of TIMP-2. Both Val and Tsn-H attenuated cardiac dysfunction, while Tsn-L showed slight improvement. These data demonstrate for the first time, that Tsn prevented cardiac fibrosis and improved cardiac function in a rat model of renovascular hypertensive independent of hypotensive effect. Tsn conferred its beneficial effects on the collagen metabolism probably through its regulation of transcript levels of the MMPs/TIMPs balance.

Alterations in mRNA expression of BACE1, cathepsin B, and glutaminyl cyclase in mice ischemic brain.

The relationship between cerebral ischemia and Alzheimer's disease has been evaluated extensively. However, the association between cerebral ischemia and the deposition of beta-amyloid (Abeta) remains to be clarified. Here, we used mice bilateral common carotid artery ligation model to investigate the alterations in mRNA expression of Abeta precursor protein cleavage enzyme 1(BACE1), cathepsin B, and glutaminyl cyclase after transient global cerebral ischemia. The reverse-transcriptase PCR assay showed that the expressions of these three Abeta-metabolism-related genes were upregulated in brain with different manner. It indicates that all these three Abeta-metabolism-related genes may participate in the acute and chronic Abeta generation after transient cerebral ischemia, and will be helpful to understand the mechanisms underlying the linkage of brain ischemia and Alzheimer's disease.