LOX-1 promotes right ventricular hypertrophy in hypoxia-exposed rats

Ezetimibe treatment reduces oxidized low-density lipoprotein in biliary cirrhotic rats

BACKGROUND

In liver cirrhosis, chronic inflammation is associated with an increase in oxidative stress, and subsequently an increase in the concentration of oxidized low-density lipoprotein (ox-LDL). Ezetimibe is a lipid-lowering agent with anti-inflammation and anti-oxidative stress activities. This study aimed to investigate the effect of ezetimibe treatment on ox-LDL in cirrhotic rats.

METHODS

Biliary cirrhosis was induced in Sprague-Dawley rats with common bile duct ligation (BDL). Sham-operated rats served as surgical controls. Ezetimibe (10 mg/kg/d) or vehicle was administered in the sham-operated or BDL rats for 4 weeks, after which hemodynamic parameters, biochemistry data, and oxidative stress were evaluated. Plasma and intrahepatic ox-LDL levels were also examined, and hepatic proteins were analyzed to explore the mechanism of ezetimibe treatment.

RESULTS

The BDL rats had typical features of cirrhosis including jaundice, impaired liver function, hyperlipidemia, and elevated ox-LDL levels compared to the sham-operated rats. Ezetimibe treatment did not affect hemodynamics, liver biochemistry, or plasma lipid levels. However, it significantly reduced oxidative stress, plasma levels of ox-LDL, and tumor necrosis factor α. In addition, ezetimibe upregulated the hepatic protein expression of an ox-LDL scavenger (lectin-like ox-LDL rececptor-1), which resulted in reductions in intrahepatic ox-LDL and fat accumulation in the BDL rats. Nevertheless, ezetimibe treatment did not ameliorate hepatic inflammation or liver fibrosis.

CONCLUSION

Ezetimibe reduced plasma and intrahepatic ox-LDL levels in the cirrhotic rats. Furthermore, it ameliorated intrahepatic fat accumulation and oxidative stress. However, ezetimibe did not alleviate hepatic fibrosis or inflammation in the biliary cirrhotic rats.

Anti-atherosclerotic effects and molecular targets of ginkgolide B from Ginkgo biloba

Bioactive compounds derived from herbal medicinal plants modulate various therapeutic targets and signaling pathways associated with cardiovascular diseases (CVDs), the world's primary cause of death. Ginkgo biloba , a well-known traditional Chinese medicine with notable cardiovascular actions, has been used as a cardio- and cerebrovascular therapeutic drug and nutraceutical in Asian countries for centuries. Preclinical studies have shown that ginkgolide B, a bioactive component in Ginkgo biloba , can ameliorate atherosclerosis in cultured vascular cells and disease models. Of clinical relevance, several clinical trials are ongoing or being completed to examine the efficacy and safety of ginkgolide B-related drug preparations in the prevention of cerebrovascular diseases, such as ischemia stroke. Here, we present a comprehensive review of the pharmacological activities, pharmacokinetic characteristics, and mechanisms of action of ginkgolide B in atherosclerosis prevention and therapy. We highlight new molecular targets of ginkgolide B, including nicotinamide adenine dinucleotide phosphate oxidases (NADPH oxidase), lectin-like oxidized LDL receptor-1 (LOX-1), sirtuin 1 (SIRT1), platelet-activating factor (PAF), proprotein convertase subtilisin/kexin type 9 (PCSK9) and others. Finally, we provide an overview and discussion of the therapeutic potential of ginkgolide B and highlight the future perspective of developing ginkgolide B as an effective therapeutic agent for treating atherosclerosis.

Down-regulation of the mitochondrial fusion protein Opa1/Mfn2 promotes cardiomyocyte hypertrophy in Su5416/hypoxia-induced pulmonary hypertension rats

BACKGROUND

Maladaptive right ventricular (RV) remodeling is the most important pathological feature of pulmonary hypertension (PH), involving processes such as myocardial hypertrophy and fibrosis. A growing number of studies have shown that mitochondria-associated endoplasmic reticulum membranes (MAMs) are involved in various physiological and pathological processes, such as calcium homeostasis, lipid metabolism, inflammatory response, mitochondrial dynamics, and autophagy/mitophagy. The abnormal expression of MAMs-related factors is closely related to the occurrence and development of heart-related diseases. However, the role of MAM-related factors in the maladaptive RV remodeling of PH rats remains unclear.

METHODS AND RESULTS

We first obtained the transcriptome data of RV tissues from PH rats induced by Su5416 combined with hypoxia treatment (SuHx) from the Gene Expression Omnibus (GEO) database. The results showed that two MAMs-related genes (Opa1 and Mfn2) were significantly down-regulated in RV tissues of SuHx rats, accompanied by significant up-regulation of cardiac hypertrophy-related genes (such as Nppb and Myh7). Subsequently, using the SuHx-induced PH rat model, we found that the downregulation of mitochondrial fusion proteins Opa1 and Mfn2 may be involved in maladaptive RV remodeling by accelerating mitochondrial dysfunction. Finally, at the cellular level, we found that overexpression of Opa1 and Mfn2 could inhibit hypoxia-induced mitochondrial fission and reduce ROS production in H9c2 cardiomyocytes, thereby retarded the progression of cardiomyocyte hypertrophy.

CONCLUSIONS

The down-regulation of mitochondrial fusion protein Opa1/Mfn2 can accelerate cardiomyocyte hypertrophy and then participate in maladaptive RV remodeling in SuHx-induced PH rats, which may be potential targets for preventing maladaptive RV remodeling.

LOX-1 mediates inflammatory activation of microglial cells through the p38-MAPK/NF-κB pathways under hypoxic-ischemic conditions

BACKGROUND

Microglial cells play an important role in the immune system in the brain. Activated microglial cells are not only injurious but also neuroprotective. We confirmed marked lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) expression in microglial cells in pathological lesions in the neonatal hypoxic-ischemic encephalopathy (nHIE) model brain. LOX-1 is known to be an activator of cytokines and chemokines through intracellular pathways. Here, we investigated a novel role of LOX-1 and the molecular mechanism of LOX-1 gene transcription microglial cells under hypoxic and ischemic conditions.

METHODS

We isolated primary rat microglial cells from 3-day-old rat brains and confirmed that the isolated cells showed more than 98% Iba-1 positivity with immunocytochemistry. We treated primary rat microglial cells with oxygen glucose deprivation (OGD) as an in vitro model of nHIE. Then, we evaluated the expression levels of LOX-1, cytokines and chemokines in cells treated with or without siRNA and inhibitors compared with those of cells that did not receive OGD-treatment. To confirm transcription factor binding to the OLR-1 gene promoter under the OGD conditions, we performed a luciferase reporter assay and chromatin immunoprecipitation assay. In addition, we analyzed reactive oxygen species and cell viability.

RESULTS

We found that defects in oxygen and nutrition induced LOX-1 expression and led to the production of inflammatory mediators, such as the cytokines IL-1β, IL-6 and TNF-α; the chemokines CCL2, CCL5 and CCL3; and reactive oxygen/nitrogen species. Then, the LOX-1 signal transduction pathway was blocked by inhibitors, LOX-1 siRNA, the p38-MAPK inhibitor SB203580 and the NF-κB inhibitor BAY11-7082 suppressed the production of inflammatory mediators. We found that NF-κB and HIF-1α bind to the promoter region of the OLR-1 gene. Based on the results of the luciferase reporter assay, NF-κB has strong transcriptional activity. Moreover, we demonstrated that LOX-1 in microglial cells was autonomously overexpressed by positive feedback of the intracellular LOX-1 pathway.

CONCLUSION

The hypoxic/ischemic conditions of microglial cells induced LOX-1 expression and activated the immune system. LOX-1 and its related molecules or chemicals may be major therapeutic candidates. Video abstract.

Chronic intermittent hypobaric hypoxia induces cardiovascular dysfunction in a high-altitude working shift model

AIMS

Chronic intermittent hypobaric hypoxia (CIHH) exposure due to shift work occurs mainly in 4 × 4 or 7 × 7 days shifts in mining, astronomy, and customs activities, among other institutions. However, the long-lasting effects of CIHH on cardiovascular structure and function are not well characterized. We aimed to investigate the effects of CIHH on the cardiac and vascular response of adult rats simulating high-altitude (4600 m) x low-altitude (760 m) working shifts.

MAIN METHODS

We analyzed in vivo cardiac function through echocardiography, ex vivo vascular reactivity by wire myography, and in vitro cardiac morphology by histology and protein expression and immunolocalization by molecular biology and immunohistochemistry techniques in 12 rats, 6 exposed to CIHH in the hypoxic chamber, and respective normobaric normoxic controls (n = 6).

KEY FINDINGS

CIHH induced cardiac dysfunction with left and right ventricle remodeling, associated with an increased collagen content in the right ventricle. In addition, CIHH increased HIF-1α levels in both ventricles. These changes are associated with decreased antioxidant capacity in cardiac tissue. Conversely, CIHH decreased contractile capacity with a marked decreased in nitric oxide-dependent vasodilation in both, carotid and femoral arteries.

SIGNIFICANCE

These data suggest that CIHH induces cardiac and vascular dysfunction by ventricular remodeling and impaired vascular vasodilator function. Our findings highlight the impact of CIHH in cardiovascular function and the importance of a periodic cardiovascular evaluation in high-altitude workers.

VPO1/HOCl/ERK pathway mediates the right ventricular remodeling in rats with hypoxic pulmonary hypertension

Right ventricular (RV) remodeling is a major feature of pulmonary arterial hypertension (PAH). Vascular peroxidase 1 (VPO1) is reported to participate in the process of PAH. This study aims to explore whether VPO1 contributes to hypoxia-induced cardiac hypertrophy and the underlying mechanisms. SD rats were exposure to continuous hypoxia (10% O₂) for 3 weeks, which showed RV hypertrophy (increases in the ratio of RV weight to tibia length, cardiac cell size and hypertrophic markers), concomitant with upregulation of VPO1, elevation in hypochlorous acid (HOCl) production and ERK phosphorylation. In hypoxia (3% O₂)-induced hypertrophic H9c2 cells, similar characteristics of cardiac hypertrophy to that of hypoxia-treated rats were observed. Administration of VPO1 siRNA or NaHS (the HOCl inhibitor) suppressed HOCl production, ERK phosphorylation, and cardiac hypertrophy. Replacement of hypoxia with NaClO (exogenous HOCl) could also induce cardiac cell hypertrophy and activate ERK signaling pathway. In addition, hypoxia-induced cardiac hypertrophy could be blocked by PD98059 (the ERK-specific inhibitor). Based on these observations, we conclude that VPO1 promotes RV remodeling in PAH rats through catalyzing HOCl production, leading to the activation of ERK signaling. Thus, VPO1 may have the potential as a therapeutic target for PAH.

ZIP12 Contributes to Hypoxic Pulmonary Hypertension by Driving Phenotypic Switching of Pulmonary Artery Smooth Muscle Cells

ABSTRACT

ZIP12, a plasmalemmal zinc transporter, reportedly promotes pulmonary vascular remodeling (PVR) by enhancing proliferation of pulmonary artery smooth muscle cells (PASMCs). However, the mechanisms of ZIP12 facilitating PASMCs proliferation remain incompletely appreciated. It has been acknowledged that proliferation-predisposing phenotypic switching of PASMCs can lead to PVR. Given that hypoxia triggers phenotypic switching of PASMCs and ZIP12 mediates PVR, this study aims to explore whether ZIP12-mediated phenotypic switching of PASMCs contributes to hypoxia-induced PVR. Rats were exposed to hypoxia (10% O2) for 3 weeks to induce PVR, and primary rat PASMCs were cultured under hypoxic condition (3% O2) for 48 hours to induce proliferation. Immunofluorescence, quantitative reverse transcription-polymerase chain reaction, and Western blot analysis were performed to detect the expression of target mRNAs and proteins. EdU incorporation and 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium assay were conducted to measure the proliferation of PASMCs. Hypoxia upregulated ZIP12 expression (both mRNA and protein) in pulmonary arteries and PASMCs. Knockdown of ZIP12 inhibited phenotypic switching of PASMCs induced by hypoxia. We propose that HIF-1α/ZIP12/pERK pathway could represent a novel mechanism underlying hypoxia-induced phenotypic switching of PASMCs. Therapeutic targeting of ZIP12 could be exploited to treat PVR.

Magnolol Attenuates Right Ventricular Hypertrophy and Fibrosis in Hypoxia-Induced Pulmonary Arterial Hypertensive Rats Through Inhibition of the JAK2/STAT3 Signaling Pathway

Right ventricular (RV) remodeling is one of the essential pathological features in pulmonary arterial hypertension (PAH). RV hypertrophy or fibrosis are the leading causes of RV remodeling. Magnolol (6, 6′, 7, 12-tetramethoxy-2,2′-dimethyl-1-β-berbaman, C18H18O2) is a compound isolated from Magnolia Officinalis. It possesses multiple pharmacological activities, such as anti-oxidation and anti-inflammation. This study aims to evaluate the effects and underlying mechanisms of magnolol on RV remodeling in hypoxia-induced PAH. In vivo, male Sprague Dawley rats were exposed to 10% O₂ for 4 weeks to establish an RV remodeling model, which showed hypertrophic and fibrotic features (increases of Fulton index, cellular size, hypertrophic and fibrotic marker expression), accompanied by an elevation in phosphorylation levels of JAK2 and STAT3; these changes were attenuated by treating with magnolol. In vitro, the cultured H9c2 cells or cardiac fibroblasts were exposed to 3% O₂ for 48 h to induce hypertrophy or fibrosis, which showed hypertrophic (increases in cellular size as well as the expression of ANP and BNP) or fibrotic features (increases in the expression of collagen Ⅰ, collagen Ⅲ, and α-SMA). Administration of magnolol and TG-101348 or JSI-124 (both JAK2 selective inhibitors) could prevent myocardial hypertrophy and fibrosis, accompanied by the decrease in the phosphorylation level of JAK2 and STAT3. Based on these observations, we conclude that magnolol can attenuate RV hypertrophy and fibrosis in hypoxia-induced PAH rats through a mechanism involving inhibition of the JAK2/STAT3 signaling pathway. Magnolol may possess the potential clinical value for PAH therapy.

Hypoxia-activated platelets stimulate proliferation and migration of pulmonary arterial smooth muscle cells by phosphatidylserine/LOX-1 signaling-impelled intercellular communication

Continuous recruitment and inappropriate activation of platelets in pulmonary arteries contribute to pulmonary vascular remodeling in pulmonary hypertension (PH). Our previous study has demonstrated that lectin like oxidized low-density lipoprotein receptor-1 (LOX-1) regulates the proliferation of pulmonary arterial smooth muscle cells (PASMCs). Phosphatidylserine exposed on the surface of activated platelets is a ligand for LOX-1. However, whether hypoxia-activated platelets stimulate the proliferation and migration of PASMCs by phosphatidylserine/LOX-1 signaling-impelled intercellular communication remains unclear. The present study found that rats treated with hypoxia (10% O₂) for 21 days revealed PH with the activation of platelets and the recruitment of platelets in pulmonary arteries, and LOX-1 knockout inhibited hypoxia-induced PH and platelets activation. Notably, co-incubation of PASMCs with hypoxic PH rats-derived platelets up-regulated LOX-1 expression in PASMCs leading to the proliferation and migration of PASMCs, which was inhibited by the phosphatidylserine inhibitor annexin V or the LOX-1 neutralizing antibody. LOX-1 knockout led to decreased proliferation and migration of PASMCs stimulated by hypoxia-activated platelets. In rats, hypoxia up-regulated the phosphorylation of signal transducer and activator of transcription 3 (Stat3) and the expression of Pim-1 in pulmonary arteries. Hypoxia-activated platelets also up-regulated the phosphorylation of Stat3 and the expression of Pim-1 in PASMCs, which was inhibited by annexin V, the LOX-1 neutralizing antibody, the protein kinase C inhibitor and LOX-1 knockout. In conclusion, we for the first time demonstrated that hypoxia-activated platelets stimulated the proliferation and migration of PASMCs by phosphatidylserine/LOX-1/PKC/Stat3/Pim-1 signaling-impelled intercellular communication, thereby potentially contributing to hypoxic pulmonary vascular remodeling.

Epigenetic Regulation of Pulmonary Arterial Hypertension-Induced Vascular and Right Ventricular Remodeling: New Opportunities?

Pulmonary artery hypertension (PAH) is a rare chronic disease with high impact on patients’ quality of life and currently no available cure. PAH is characterized by constant remodeling of the pulmonary artery by increased proliferation and migration of pulmonary arterial smooth muscle cells (PASMCs), fibroblasts (FBs) and endothelial cells (ECs). This remodeling eventually leads to increased pressure in the right ventricle (RV) and subsequent right ventricle hypertrophy (RVH) which, when left untreated, progresses into right ventricle failure (RVF). PAH can not only originate from heritable mutations, but also develop as a consequence of congenital heart disease, exposure to drugs or toxins, HIV, connective tissue disease or be idiopathic. While much attention was drawn into investigating and developing therapies related to the most well understood signaling pathways in PAH, in the last decade, a shift towards understanding the epigenetic mechanisms driving the disease occurred. In this review, we reflect on the different epigenetic regulatory factors that are associated with the pathology of RV remodeling, and on their relevance towards a better understanding of the disease and subsequently, the development of new and more efficient therapeutic strategies.

Nox2 Upregulation and p38α MAPK Activation in Right Ventricular Hypertrophy of Rats Exposed to Long-Term Chronic Intermittent Hypobaric Hypoxia

One of the consequences of high altitude (hypobaric hypoxia) exposure is the development of right ventricular hypertrophy (RVH). One particular type of exposure is long-term chronic intermittent hypobaric hypoxia (CIH); the molecular alterations in RVH in this particular condition are less known. Studies show an important role of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase complex-induced oxidative stress and protein kinase activation in different models of cardiac hypertrophy. The aim was to determine the oxidative level, NADPH oxidase expression and MAPK activation in rats with RVH induced by CIH. Male Wistar rats were randomly subjected to CIH (2 days hypoxia/2 days normoxia; n = 10) and normoxia (NX; n = 10) for 30 days. Hypoxia was simulated with a hypobaric chamber. Measurements in the RV included the following: hypertrophy, Nox2, Nox4, p22phox, LOX-1 and HIF-1α expression, lipid peroxidation and H₂O₂ concentration, and p38α and Akt activation. All CIH rats developed RVH and showed an upregulation of LOX-1, Nox2 and p22phox and an increase in lipid peroxidation, HIF-1α stabilization and p38α activation. Rats with long-term CIH-induced RVH clearly showed Nox2, p22phox and LOX-1 upregulation and increased lipid peroxidation, HIF-1α stabilization and p38α activation. Therefore, these molecules may be considered new targets in CIH-induced RVH.

Oxidative Stress, Kinase Activity and Inflammatory Implications in Right Ventricular Hypertrophy and Heart Failure under Hypobaric Hypoxia

High altitude (hypobaric hypoxia) triggers several mechanisms to compensate for the decrease in oxygen bioavailability. One of them is pulmonary artery vasoconstriction and its subsequent pulmonary arterial remodeling. These changes can lead to pulmonary hypertension and the development of right ventricular hypertrophy (RVH), right heart failure (RHF) and, ultimately to death. The aim of this review is to describe the most recent molecular pathways involved in the above conditions under this type of hypobaric hypoxia, including oxidative stress, inflammation, protein kinases activation and fibrosis, and the current therapeutic approaches for these conditions. This review also includes the current knowledge of long-term chronic intermittent hypobaric hypoxia. Furthermore, this review highlights the signaling pathways related to oxidative stress (Nox-derived O₂^.- and H₂O₂), protein kinase (ERK5, p38α and PKCα) activation, inflammatory molecules (IL-1β, IL-6, TNF-α and NF-kB) and hypoxia condition (HIF-1α). On the other hand, recent therapeutic approaches have focused on abolishing hypoxia-induced RVH and RHF via attenuation of oxidative stress and inflammatory (IL-1β, MCP-1, SDF-1 and CXCR-4) pathways through phytotherapy and pharmacological trials. Nevertheless, further studies are necessary.

LOX-1 and atherosclerotic-related diseases

Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1), a scavenger receptor of oxidized low-density lipoprotein (ox-LDL) found in various cells, plays a crucial role in the formation and progression of atherosclerotic plaques. Animal studies have suggested that LOX-1 mediates the balance between internalization and degeneration of endothelial cells, thereby contributing to various steps in the atherosclerotic process, from initiation to plaque rupture. Under pathological conditions, the extracellular domain of membrane bound LOX-1 can be largely proteolytically cleaved into a soluble form (sLOX-1), which is proportional and linked to the LOX-1 expression level. Circulating levels of sLOX-1 are regarded as a risk biomarker for plaque rupture and acute coronary syndrome (ACS). Recently, studies have shown that sLOX-1 is also elevated in patients with acute stroke and can be a predictive biomarker for acute stroke. With the discovery of the vital role of LOX-1 in atherosclerosis, there is growing focus on the influence of LOX-1 in atherosclerotic-related diseases, including coronary arterial disease(CAD), stroke, and other cardiovascular events. Genetic polymorphisms of LOX-1 have been investigated and have been found to modulate the risk of these diseases. Most polymorphisms have been found to be risk factors, except for the splicing isoform LOXIN. This review concludes with a discussion of the potential future applications of LOX-1 for atherosclerotic-related diseases.

Review on Chamber-Specific Differences in Right and Left Heart Reactive Oxygen Species Handling

Reactive oxygen species (ROS) exert signaling character (redox signaling), or damaging character (oxidative stress) on cardiac tissue depending on their concentration and/or reactivity. The steady state of ROS concentration is determined by the interplay between its production (mitochondrial, cytosolic, and sarcolemmal enzymes) and ROS defense enzymes (mitochondria, cytosol). Recent studies suggest that ROS regulation is different in the left and right ventricle of the heart, specifically by a different activity of superoxide dismutase (SOD). Mitochondrial ROS defense seems to be lower in right ventricular tissue compared to left ventricular tissue. In this review we summarize the current evidence for heart chamber specific differences in ROS regulation that may play a major role in an observed inability of the right ventricle to compensate for cardiac stress such as pulmonary hypertension. Based on the current knowledge regimes to increase ROS defense in right ventricular tissue should be in the focus for the development of future therapies concerning right heart failure.

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.

Contribution of lectin-like oxidized low-density lipoprotein receptor-1 and LOX-1 modulating compounds to vascular diseases

The lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) is the major receptor for binding and uptake of oxidized low-density lipoprotein (oxLDL) in endothelial cells. LOX-1 is also expressed in macrophages, smooth muscle cells and platelets. Following internalization of oxLDL, LOX-1 initiates a vicious cycle from activation of pro-inflammatory signaling pathways, thus promoting an increased reactive oxygen species formation and secretion of pro-inflammatory cytokines. LOX-1 plays a pivotal role in the development of endothelial dysfunction, foam cell and advanced lesions formation as well as in myocardial ischemia. Furthermore, it is known that LOX-1 plays a pivotal role in mitochondrial DNA damage, vascular cell apoptosis, and autophagy. A large number of studies provide evidence of a LOX-1's role in endothelial dysfunction, hypertension, diabetes, and obesity. In addition, novel insights into LOX-1 ligands and the activated signaling pathways have been gained. Recent studies have shown an interaction of LOX-1 with microRNA's, thus providing novel tools to regulate LOX-1 function. Because LOX-1 is increased in atherosclerotic plaques and contributes to endothelial dysfunction, several compounds were tested in vivo and in vitro to modulate the LOX-1 expression in therapeutic approaches.