Antiatherosclerotic effects of corilagin via suppression of the LOX-1/MyD88/NF-κB signaling pathway in vivo and in vitro.

Corilagin, a natural polyphenol compound isolated from Phyllanthus urinaria L., exerts various pharmacological effects, such as antihyperglycemic, antitumor, and antioxidative stress properties, but the mechanisms underlying the antiatherosclerotic effects of corilagin have not been entirely elucidated. In the present study, we investigated the antiatherosclerotic effects of corilagin using a high-fat diet (HFD)-induced atherosclerotic rabbit model and ox-LDL-induced vascular smooth muscle cells (VSMCs) and explored the underlying molecular mechanisms. The serum lipid levels were measured through an enzymatic colorimetric assay. A histological analysis of rabbit aortas was performed after hematoxylin-eosin and oil red O staining. The proliferation of ox-LDL-induced VSMCs was detected using MTT assays, and the migration of cells was determined by wound scratch assays. In addition, the mRNA and protein expression levels of lectin-like ox-LDL receptor-1 (LOX-1), myeloid differentiation factor 88 (MyD88), nuclear factor-kappa B (NF-κB), monocyte chemoattractant protein-1 (MCP-1) and tumor necrosis factor α (TNF-α) were detected by reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting assays. Our results indicate that corilagin significantly reduced the serum levels of TC, TG and LDL-C, increased the HDL-C levels, decreased the intimal thickening in the thoracic aorta, and reduced the formation of foam cells in an HFD-induced rabbit atherosclerosis model. Moreover, corilagin suppressed the proliferation and migration of ox-LDL-induced VSMCs and reduced LOX-1, MyD88, NF-κB, MCP-1, and TNF-α mRNA and protein expression in vivo and in vitro. These data demonstrate that corilagin exerts antiatherosclerotic effects in vivo and in vitro and that the mechanisms may be closely associated with downregulation of the LOX-1/MyD88/NF-κB pathway.

Comparative Analysis of the Rabbit Endothelial Progenitor Cells from Bone Marrow and Peripheral Blood Treated with Selenium Nanoparticles.

BACKGROUND: Selenium Nanoparticles (Se-NPs) are known for their antioxidant and anti-inflammatory activities, which are effective in preventing oxidative damage and improving physiological processes. OBJECTIVES: This study aimed at investigating the effects of biosynthesized Se-NPs on bone marrow-derived Endothelial Progenitor Cells (bone marrow-derived EPCs) and blood-derived endothelial progenitor cells (blood-derived EPCs) isolated from rabbits in vitro. METHODS: The cultured EPCs incubated with biosynthesized Se-NPs at the concentrations of 0.19, 0.38, 0.76, 1.71, 3.42, 7.03, 14.25, 28.50, 57, 114, and 228µg/ml for 48h. After screening the proliferative potential of the Se-NPs by the MTT assay, the best concentrations were selected for Real-Time quantitative Polymerase Chain Reaction (RT-qPCR). Real-time quantification of Vascular Cell Adhesion Molecule 1 (VCAM-1), lectin-like oxidized Low-Density Lipoprotein (LDL) receptor-1 (LOX-1), endothelial Nitric Oxide Synthase (eNOS), and Monocyte Chemoattractant Protein-1 (MCP-1) gene expressions were analyzed by normalizing with Glyceraldehyde- 3-Phosphate Dehydrogenase (GAPDH) as an endogenous reference gene. RESULTS: Blood-derived EPCs and bone marrow-derived EPCs showed morphological differences before treatment in vitro. Se-NPs treated EPCs indicated a significant dose-dependent proliferative activity (p<0.01). In general, the expression levels of VCAM-1, LOX-1, and MCP-1 mRNA were significantly decreased (p<0.01), whereas that of the eNOS expression was significantly increased at the concentrations of 7.3 and 14.25µg/ml (p<0.01). Although the expressions of MCP-1, LOX-1, and eNOS mRNA were decreased at certain concentrations of Se-NPs (p<0.01 and p<0.05, respectively) in the treated bone marrow-derived EPCs, no significant differences were observed in the VCAM-1 mRNA expression levels in bone marrow-derived EPCs compared with the control group (p>0.05). CONCLUSION: This was the first report to demonstrate the effects of Se-NPs on proliferative, anti-oxidative, and anti-inflammatory activities for bone marrow-derived EPCs and blood-derived EPCs. Our findings suggested that Se-NPs could be considered as an effective agent that may ameliorate vascular problems.

Nerolidol inhibits the LOX-1 / IL-1ß signaling to protect against the Aspergillus fumigatus keratitis inflammation damage to the cornea.

PURPOSE: Nerolidol, a naturally occurring sesquiterpene has both anti-microbial and anti-inflammatory properties. The current study aims to investigate the antifungal and the anti-inflammatory effects of nerolidol against mouse Aspergillus fumigatus (A. fumigatus) keratitis. METHODS: The minimum inhibitory concentration (MIC) and cytotoxicity tests were used to study the antifungal ability. For in vivo and in vitro studies, the mouse corneas and the human corneal epithelial cells (HCECs) infected with A. fumigatus spores were intervented with nerolidol or phosphate buffer saline (PBS). Thereafter, the effect of the nerolidol on the response against inflammation was analyzed using the following parameters: recruitment of the neutrophils or macrophages and the expression of the lectin-type oxidized low density lipoprotein receptor-1 (LOX-1) and interleukin 1ß (IL-1ß). Techniques used were the slit lamp, immunofluorescence, myeloperoxidase (MPO) detection, quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot. RESULTS: Nerolidol directly inhibits the growth of A. fumigatus. The administration of nerolidol reduced the severity of fungal keratitis with infiltration of fewer inflammatory cells and reduced levels of the LOX-1, as well the anti-inflammatory cytokines such as IL-1ß were reduced compared with the PBS group. Additionally, in vitro studies showed that treatment with nerolidol inhibited the production of the LOX-1 / IL-1ß levels in A. fumigatus stimulated HCECs. CONCLUSION: Nerolidol attenuated the A. fumigatus keratitis inflammatory response by inhibiting the growth of A. fumigatus, reducing the recruitment of the neutrophils and the macrophages, and inhibiting the LOX-1/ IL-1ß signaling.

Crocin treatment decreased pancreatic atrophy, LOX-1 and RAGE mRNA expression of pancreas tissue in cholesterol-fed and streptozotocin-induced diabetic rats.

Objective Oxidative stress in diabetic mellitus is a consequence of oxidative stress, which plays a critical role in the pathogenesis of diabetic tissue damage. Receptors for advanced glycation end products and for oxidized low-density lipoproteins (LDL) have critical contribution in oxidative tissue damage. The present study investigated whether anti-diabetic effects of Crocin via modulation of mRNA expression of RAGE and LOX-1 receptors in diabetic rats. Methods In the current study, high-fat cholesterol (HFC) and streptozotocin (40 mg/kg) used to induce type II diabetes. Experimental groups as follows: (Group 1: control); (Group 2: control treatment [Crocin]); (Group 3: DM [STZ]); (Group 4: DM treatment [STZ + Crocin]); (Group 5; DM + HFC [STZ + HFC]); (Group 6; DM + HFC treatment [STZ + HFC + Crocin]). Crocin (20 mg/kg/day, i.p.) administered in treatment groups for 60 days. Serum glucose and cholesterol levels evaluated on days 5, 30 and 60 after induction of DM. Pancreatic tissue from all group removed on day 60 for histological and RT-PCR analysis. Results Application of Crocin significantly decreased serum cholesterol levels on day 60 after induction of DM in diabetic + HFC rats. Moreover, Crocin significantly decreased serum glucose levels on days 30 and 60 both in diabetic and diabetic + HFC rats. Crocin partially prevented the atrophic effects of STZ on both exocrine and endocrine parts of pancreas. Additionally, Crocin significantly decreased LOX-1 and RAGE mRNA expression OF pancreas in diabetic rats. Conclusion The current study suggested that Crocin suppressed atrophic change of the pancreas by decrease of LOX-1 and RAGE mRNA expression in diabetic rats.

Nigella sativa L. seed regulated eNOS, VCAM-1 and LOX-1 genes expression and improved vasoreactivity in aorta of diabetic rat.

ETHNOPHARMACOLOGICAL RELEVANCE: Nigella sativa L. seed has been widely used in traditional medicine for the treatment of diabetes. The major reason for vascular complications in diabetic patients is endothelial dysfunction. However, the impact of N. sativa seed on endothelial dysfunction in diabetes remains unclear. AIM OF THE STUDY: This study was conducted to evaluate the effect of the hydroalcoholic extract of N. sativa seed on eNOS, VCAM-1, and LOX-1 genes expression and the vasoreactivity of aortic rings to acetylcholine (Ach) in streptozotocin (STZ)-induced diabetic rat. MATERIALS AND METHODS: Treated rats received N. sativa seed extract (100, 200, and 400 mg/kg) daily by gavage for 6 weeks. The fasting blood glucose and lipids were measured and atherogenic index of plasma (AIP) was calculated. The endothelium-dependent vasoreactivity responses of isolated aortic rings were evaluated in the presence of cumulative concentrations of Ach (10-8-10-5 M). eNOS, VCAM-1, and LOX-1 genes expression in aortic tissue was assessed by using real time polymerase chain reaction (PCR). RESULTS: Male diabetic Wistar rats treated with N. sativa seed extract for six weeks reduced serum glucose and lipids and improved AIP. The vasorelaxant responses of aortic rings to Ach were markedly improved. N. sativa seed significantly increased eNOS in mRNA expression level and function, while it decreased VCAM-1 and LOX-1 expressions in vascular cells of aortic tissue which assessed only in mRNA level. CONCLUSIONS: The results of this study showed that N. sativa seed more likely, has antidiabetic and antihyperlipidemic properties and improved vasoreactivity, endothelial dysfunction, and vascular inflammation in diabetic rats' aorta.

Protective effect of Naoxintong against cerebral ischemia reperfusion injury in mice.

ETHNOPHARMACOLOGICAL RELEVANCE: Naoxintong (NXT), a renowned traditional Chinese medicine in China, has been used for the treatment of acute and chronic cardio-cerebrovascular diseases in clinic for more than 20 years. AIM OF THE STUDY: To evaluate the potential neuroprotective effect of NXT against ischemia reperfusion (I/R) injury in mice and investigate the underlying mechanisms. MATERIALS AND METHODS: Focal cerebral I/R injury in adult male CD-1 mice was induced by transient middle cerebral artery occlusion (tMCAO) for 1h followed by reperfusion for 23h. Mice were randomly divided into five groups: Sham group; tMCAO group; Vehicle group; NXT-treated groups at doses of 0.36g/kg and 0.54g/kg. The effects of NXT on murine neurological function were estimated by neurological defect scores, infarct volume and brain water content at 24h after tMCAO. Immunohistochemistry and Western blot were used to detect the expression of LOX-1, pERK1/2 and NF-κB at 24h after tMCAO. qRT-PCR was used to detect the expression of LOX-1 and NF-κB at 24h after tMCAO. RESULTS: Compared with Vehicle group, 0.54g/kg group of NXT significantly ameliorated neurological outcome, infarction volume and brain water content, decreased the expression of LOX-1, pERK1/2 and NF-κB (P<0.05). CONCLUSION: NXT protected the mice brain against I/R injury, and this protection maybe associated with the down-regulation of LOX-1, pERK1/2 and NF-κB expression.

A fermented bean flour extract downregulates LOX-1, CHOP and ICAM-1 in HMEC-1 stimulated by ox-LDL.

This study focused on an extract from fermented flour from the Lady Joy variety of the common bean Phaseolus vulgaris. The extract, Lady Joy lysate (Lys LJ), is enriched in antioxidant compounds during the fermentation. We assessed it for its protective effect on endothelial cells treated with oxidized-LDL (ox-LDL). The oxidative stress was determined by measuring the contents of thiobarbituric acid-reactive substances and reactive oxygen metabolites. ICAM-1, ET-1 and IL-6 concentrations were assessed using ELISA. LOX-1 and CHOP expression were analyzed using both quantitative RT-PCR and ELISA or western blotting. Ox-LDL treatment induced significant oxidative stress, which was strongly reduced by pre-treatment with the extract. The ox-LDL exposure significantly enhanced ICAM-1, IL-6 and ET-1 levels over basal levels. Lys LJ pre-treatment exerted an inhibitory effect on ox-LDL-induced endothelial activation with ICAM-1 levels comparable to those for the untreated cells. IL-6 and ET-1 production, although reduced, was still significantly higher than for the control. Both LOX-1 and CHOP expression were upregulated after ox-LDL exposure, but this effect was significantly decreased after Lys LJ pre-treatment. Lys LJ alone did not alter the ICAM-1, IL-6 and ET-1 concentrations or CHOP expression, but it did significantly lower the LOX-1 protein level. Our data suggest that Lys LJ is an effective antioxidant that is able to inhibit the oxidation process, but that it is only marginally active against inflammation and ET-1 production in HMEC-1 exposed to ox-LDL.

Modulation of oxidized-LDL receptor-1 (LOX1) contributes to the antiatherosclerosis effect of oleanolic acid.

Oleanolic acid (OA) is a bioactive pentacyclic triterpenoid. The current work studied the effects and possible mechanisms of OA in atherosclerosis. Quails (Coturnix coturnix) were treated with high fat diet with or without OA. Atherosclerosis was assessed by examining lipid profile, antioxidant status and histology in serum and aorta. Human umbilical vein endothelial cells (HUVECs) were exposed to 200µg/mL ox-LDL for 24h, then cell viability was assessed with MTT assay; reactive oxygen species (ROS) was assessed with DCFDA staining. Expression levels of LOX-1, NADPH oxidase subunits, nrf2 and ho-1 were measured with real time PCR and western blotting. Furthermore, LOX-1 was silenced with lentivirus and the expression levels assessment was repeated. OA treatment improved the lipid profile and antioxidant status in quails fed with high fat diet. Histology showed decreased atherosclerosis in OA treated animals. Ox-LDL exposure decreased viability and induced ROS generation in HUVECs, and this progression was alleviated by OA pretreatment. Moreover, elevated expression of LOX-1, NADPH oxidase subunits, nrf2 and ho-1 were observed in ox-LDL exposed HUVECs. OA pretreatment prevented ox-LDL induced increase of LOX-1 and NADPH oxidase subunits expression, while further increased nrf2 and ho-1 expression. Silencing of LOX-1 abolished ox-LDL induced effects in cell viability, ROS generation and gene expression. OA could alleviate high fat diet induced atherosclerosis in quail and ox-LDL induced cytotoxicity in HUVECs; the potential mechanism involves modulation of LOX-1 activity, including inhibition of expression of NADPH oxidase subunits and increase of the expression of nrf2 and ho-1.

Cryptotanshinone, an orally bioactive herbal compound from Danshen, attenuates atherosclerosis in apolipoprotein E-deficient mice: role of lectin-like oxidized LDL receptor-1 (LOX-1).

BACKGROUND AND PURPOSE: Cryptotanshinone (CTS) is a major bioactive diterpenoid isolated from Danshen, an eminent medicinal herb that is used to treat cardiovascular disorders in Asian medicine. However, it is not known whether CTS can prevent experimental atherosclerosis. The present study was designed to investigate the protective effects of CTS on atherosclerosis and its molecular mechanisms of action. EXPERIMENTAL APPROACH: Apolipoprotein E-deficient (ApoE(-/-)) mice, fed an atherogenic diet, were dosed daily with CTS (15, 45 mg kg(-1) day(-1)) by oral gavage. In vitro studies were carried out in oxidized LDL (oxLDL)-stimulated HUVECs treated with or without CTS. KEY RESULTS: CTS significantly attenuated atherosclerotic plaque formation and enhanced plaque stability in ApoE(-/-) mice by inhibiting the expression of lectin-like oxLDL receptor-1 (LOX-1) and MMP-9, as well as inhibiting reactive oxygen species (ROS) generation and NF-κB activation. CTS treatment significantly decreased the levels of serum pro-inflammatory mediators without altering the serum lipid profile. In vitro, CTS decreased oxLDL-induced LOX-1 mRNA and protein expression and, thereby, inhibited LOX-1-mediated adhesion of monocytes to HUVECs, by reducing the expression of adhesion molecules (intracellular adhesion molecule 1 and vascular cellular adhesion molecule 1). Furthermore, CTS inhibited NADPH oxidase subunit 4 (NOX4)-mediated ROS generation and consequent activation of NF-κB in HUVECs. CONCLUSIONS AND IMPLICATIONS: CTS was shown to have anti-atherosclerotic activity, which was mediated through inhibition of the LOX-1-mediated signalling pathway. This suggests that CTS is a vasculoprotective drug that has potential therapeutic value for the clinical treatment of atherosclerotic cardiovascular diseases.

[Effect of Antrodia cinnamomea on gene expression related to aortal endothelial injury in rats with hyperlipidemia].

OBJECTIVE: To investigate the effect of Antrodia cinnamomea on gene expression related to aortal endothelial injury of rats with hyperlipidemia. METHOD: Fifty SD rats were randomly divided into five groups: the normal control group (NG), the model group (MG), the antrodia cinnamomea groups of low, middle and high doses (AC-LG, AC-MG, AC-HG, 250, 500, 1 000 mg x kg(-1)). The rats were fed with high-fat diets to establish the hyperlipidemia model. After the drug administration for 10 weeks, their serum lipid, SOD, MDA and ox-LDL, LOX-1, P38 MAPK and NF-kappaB mRNA and protein expression were respectively determined, and the aortal endothelial injury was observed under electron microscope. RESULT: In the model group, the contents of TC, TG and LDL-C significant increased (P < 0.01), whereas the content of HDL-C significant decreased (P < 0.01). Compared with the model group, both the AC-M group and the AC-H group showed reduction in endothelial injury and significant decrease in the content of TC, TG and LDL-C (P < 0.05 or P < 0.01). The content of HDL-C increased, but with no significant difference. SOD activity in serum remarkably increased (P < 0.05 or P < 0.01), MDA and ox-LDL levels dramatically decreased (P < 0.05 or P < 0.01). CONCLUSION: A. cinnamomea can alleviate endothelial lipid injury by inhibiting the expressions of LOX-1, P38MAPK and NF-kappaB in aorta and better protect aortal endothelial cells from oxidative lipid injury.

[Effects of electroacupuncture on the expression of oxidized low-density lipoprotein and its receptors in rats with coronary atherosclerotic heart disease].

OBJECTIVE: To explore action mechanism of electroacupuncture for coronary atherosclerotic heart disease (CHD) in order to provide experimental support for clinical acupoint selection. METHODS: Among sixty clean-grade healthy male Wistar rats, twenty-four cases were randomly selected as a normal control group and an electroacupuncture (EA) preconditioning group, 12 cases in each one. Then rats in the EA preconditioning group and the rest 36 rats were fed with high fat diet for 12 weeks to duplicate the CHD model. When the models were successfully established, the rats were randomly divided into a model control group, an EA group and a medication group, 12 cases in each one. EA was applied with Hwa-to SDZ-IV apparatus in the EA preconditioning group at "Neiguan" (PC 6) and "Xinshu" (BL 15), 1 mA in current intensity, 2 Hz in frequency, 30 min per times, once every other day for 14 weeks. When model was established, the same acupoint and method was used in the EA group for 2 weeks while intragastric administration of atorvastatin mixed suspension, 0.25 mg/kg, once a day, was applied in the medication group for 2 weeks. The content of oxidized low-density lipoprotein (oxLDL) in the serum was tested by double antibody enzyme-linked immunosorbent assay (ELISA) while content of lectin-like oxidized low density lipoprotein receptor-1 (LOX-1) in coronary arterial tissue was test by western blot method. Expression of LOX-1 mRNA was tested by fluorogenic quantitative polymerase chain reaction (PCR). RESULTS: After model was duplicated successfully, the content of oxLDL in the serum and the expression of LOX-1 and its mRNA in coronary arterial tissue in the model control group were increased significantly compared with those in the normal control group (all P < 0.01). Compared with the model control group, the content of oxLDL in the serum and the expression of LOX-1 and its mRNA in coronary arterial tissue in the EA preconditioning group, EA group and medication group were significantly reduced (all P < 0.01). CONCLUSION: The electroacupuncture at "Neiguan" (PC 6) and "Xinshu" (BL 15) could effectively reduce the content of oxLDL in the serum and expression of LOX-1 and its mRAN in coronary arterial tissue in CHD rats. The oxidative modificatory low-density lipoprotein and its specific receptor system could be one of the ways to prevention and treatment of acupuncture for CHD.

Paeonol suppresses oxidized low-density lipoprotein induced endothelial cell apoptosis via activation of LOX-1/p38MAPK/NF-κB pathway.

Paeonol is an active compound isolated from traditional Chinese medicine, and has been shown to have anti-atherosclerosis, anti-inflammatory, antioxidant effects. The present investigation was undertaken to determine the suppression effects of paeonol on oxidized low-density lipoprotein (ox-LDL) induced endothelial cell line HUVEC apoptosis and to uncover some of the underlying mechanisms of these effects. Cell viability and lactate dehydrogenase (LDH) were measured to evaluate the cell injuries. Apoptosis was evaluated by Hoechst 33342 staining and flow cytometry. Intracellular reactive oxygen species (ROS) generation was detected by 2',7'-dichlorofluorescein diacetate (DCFH-DA). Real-time PCR was used to confirm the expression of LOX-1 mRNA. Western blotting was used to evaluate the protein expression of LOX-1 and Bcl-2, as well as caspase-3 cleavage, p38-mitogen-activated protein kinase (p38MAPK) phosphorylation. NF-κB nuclear translocation was detected by Western blotting and immunofluorescence. Caspase-3 activity was measured using a colorimetric protease assay kit. The results showed that ox-LDL significantly decreased cell viability and increased the LDH release, as well as the apoptotic rate (P<0.01). Pre-treatment of paeonol resulted in remarkable increase of cell viability, decrease of LDH release and cell apoptosis in a concentration-dependent manner. Besides, ox-LDL caused the up-regulation of LOX-1, the down-regulation of Bcl-2, the phosphorylation of p38MAPK, the translocation of NF-κB and the activation of caspase-3. Paeonol pre-treatment reversed these effects introduced by ox-LDL. Moreover, paeonol also showed its inhibition effects on ox-LDL induced ROS overproduction. These results indicate the preventive effects of paeonol on ox-LDL induced endothelial cell apoptosis. The effects might, at least partly, be obtained via inhibition of LOX-1-ROS- p38MAPK-NF-κB signaling pathway.

Tanshinone II-A inhibits oxidized LDL-induced LOX-1 expression in macrophages by reducing intracellular superoxide radical generation and NF-κB activation.

Lectin-like oxidized LDL (oxLDL) receptor-1 (LOX-1), a novel scavenger receptor highly expressed in human and experimental atherosclerotic lesions, is responsible for the uptake of oxLDL in vascular cells. We demonstrated previously that Tanshinone II-A (Tan), a pharmacologically active compound extracted from the rhizome of the Chinese herb Salvia miltiorrhiza Bunge, inhibits atherogenesis in hypercholesterolemic rats, rabbits, and apolipoprotein-E deficient (ApoE⁻/⁻) mice. However, the precise mechanism by which Tan protects against atherogenesis remains to be elucidated. Therefore, we hypothesized that Tan can suppress the uptake of oxLDL by diminishing the expression of LOX-1 via suppression of NF-κB signaling pathway, thereby contributing to reduced macrophage foam cell formation. In cultured murine macrophages, oxLDL induced LOX-1 expression at the mRNA and protein levels, was abrogated by addition of Tan or pyrrolidinedithiocarbamic acid ammonium salt (PDTC), a widely used inhibitor of NF-κB, suggesting the involvement of NF-κB. Tan also reduced LOX-1 expression in atherosclerotic lesions of ApoE⁻/⁻ mice fed a high cholesterol diet. Mechanistically, Tan suppressed the nuclear translocation of NF-κB P65 subunit and phosphorylation of IκB-α induced by oxLDL. Electrophoretic mobility shift assay (EMSA) demonstrated that Tan inhibited the nuclear protein binding to NF-κB consensus sequence. Functionally, we observed that Tan inhibited DiI-oxLDL uptake by macrophages in a fashion similar to that produced by LOX-1 neutralizing antibody. Our current findings reveal a novel mechanism by which Tan protects against atherogenesis and shed new light on the potential therapeutic application of Tan to the treatment and prevention of atherosclerotic cardiovascular diseases.

Modulation of blood cell gene expression by DHA supplementation in hypertriglyceridemic men.

Our previous study with docosahexaenoic acid (DHA) supplementation to hypertriglyceridemic men showed that DHA reduced several risk factors for cardiovascular disease, including the plasma concentration of inflammatory markers. To determine the effect of DHA supplementation on the global gene expression pattern, we performed Affymetrix GeneChip microarray analysis of blood cells [treated with lipopolysaccharide (LPS) or vehicle] drawn before and after the supplementation of DHA from the hypertriglyceridemic men who participated in that study. Genes that were significantly differentially regulated by the LPS treatment and DHA supplementation were identified. Differential regulation of 18 genes was then verified by quantitative real-time polymerase chain reaction (qRT-PCR). Both microarray and qRT-PCR data showed that DHA supplementation significantly suppressed the expression of low-density lipoprotein (LDL) receptor and cathepsin L1, both of which were also up-regulated by LPS. DHA supplementation also suppressed oxidized LDL (lectin-like) receptor 1 (OLR1). However, LPS did not induce OLR1 mRNA expression. Enrichment with Gene Ontology categories demonstrated that the genes related to transcription factor activity, immunity, host defense and inflammatory responses were inversely regulated by LPS and DHA. These results provide supporting evidence for the anti-inflammatory effects of DHA supplementation, and reveal previously unrecognized genes that are regulated by DHA and are associated with risk factors of cardiovascular diseases.

LOX-1/LOXIN: the yin/yang of atheroscleorosis.

Atherosclerosis is the first cause of death in industrialized countries. Together with traditional risk factors (male gender, hypercholesterolemia, hypertension, diabetes, smoking and age), non-traditional risk factors have also been described as predisposing to this disease. Among these, oxidized low density lipoproteins (OxLDL) have been described in correlation to many proatherogenic processes. Many of the effects of OxLDL are mediated by the lectin like oxidized low density lipoprotein receptor 1 (LOX-1), expressed on endothelial cells, macrophages, SMCs and platelets. LOX-1 is encoded by the lectin like oxidized low density lipoprotein receptor 1 (OLR1) gene, located in the p12.3-p13.2 region of human chromosome 12. Variations on this gene have been studied extensively both at the functional and epidemiological level. Despite the fact that functional roles for two variants have been demonstrated, the epidemiological studies have provided inconsistent and inconclusive results. Of particular interest, it has been demonstrated that a linkage disequilibirum block of SNPs located in the intronic sequence of the OLR1 gene modulates the alternative splicing of OLR1 mRNA, leading to different ratios of LOX-1 full receptor and LOXIN, an isoform lacking part of the functional domain. As demonstrated, LOXIN acts by blocking the negative effective of LOX-1 activation. Here we review the state of the art regarding LOX-1, LOXIN, and the functional effects that are associated with the interaction of these molecules.

The protective effect of bergamot oil extract on lecitine-like oxyLDL receptor-1 expression in balloon injury-related neointima formation.

Lectin-like oxyLDL receptor-1 (LOX-1) has recently been suggested to be involved in smooth muscle cell (SMC) proliferation and neointima formation in injured blood vessels. This study evaluates the effect of the nonvolatile fraction (NVF), the antioxidant component of bergamot essential oil (BEO), on LOX-1 expression and free radical generation in a model of rat angioplasty. Common carotid arteries injured by balloon angioplasty were removed after 14 days for histopathological, biochemical, and immunohistochemical studies. Balloon injury led to a significant restenosis with SMC proliferation and neointima formation, accompanied by increased expression of LOX-1 receptor, malondialdehyde and superoxide formation, and nitrotyrosine staining. Pretreatment of rats with BEO-NVF reduced the neointima proliferation together with free radical formation and LOX-1 expression in a dose-dependent manner. These results suggest that natural antioxidants may be relevant in the treatment of vascular disorders in which proliferation of SMCs and oxyLDL-related endothelial cell dysfunction are involved.

Lysophosphatidylcholine upregulates LOX-1, chemokine receptors, and activation-related transcription factors in human T-cell line Jurkat.

In arteriosclerosis, activated T cells infiltrating the atherosclerotic lesions are directly involved in the pathogenesis of these vascular disorders. Infiltration and accumulation of T cells into the vascular wall occur at the earliest stage of atherosclerosis. The atherosclerotic lesion also sees the accumulation of modified lipids such as lysophosphatidylcholine (lysoPC), the main phospholipid component of oxidized low-density lipoprotein. However, it remains less clear how lysoPC affects CD4 T cells. Therefore, we assessed the effect of lysoPC on various mRNA expressions in human T cells using real-time quantitative Reverse Transcription-PCR. Exposure of Jurkat cells (a human CD4 T-cell line) to lysoPC resulted in upregulation of CXCR4 and CCR5 chemokine receptors, receptor for oxidized low-density lipoprotein (LOX-1), the transcription factors, nuclear factor-kappa beta (NF-kB) and Yin Yang 1, and target molecules of NF-kB, A1/Bfl1/BCL2A1 and c-IAP1/BIRC2, in a dose-dependent manner. These data indicate that lysoPC is a positive regulator of the inflammatory response in human CD4 T cells. Further, it suggested that lysoPC and CD4 T cells accumulating in atherosclerotic lesions contribute to the development of arteriosclerosis.

Mulberry leaf aqueous fractions inhibit TNF-alpha-induced nuclear factor kappaB (NF-kappaB) activation and lectin-like oxidized LDL receptor-1 (LOX-1) expression in vascular endothelial cells.

Mulberry (Morus Alba L., family Moraceae) leaf extracts have various biological effects including inhibition of oxidative modification of low-density lipoprotein (LDL), which is the major cause of atherosclerosis. Endothelial dysfunction elicited by oxidized LDL (Ox-LDL) has been implicated in atherogenesis. Lectin-like Ox-LDL receptor-1 (LOX-1), a cell-surface receptor for atherogenic Ox-LDL, appears to mediate Ox-LDL-induced inflammation, which may be crucial in atherogenesis. Previous studies revealed that expression of LOX-1 is highly inducible by proinflammatory stimuli, including tumor necrosis factor-alpha (TNF-alpha), lipopolysaccharide (LPS), and transforming growth factor-beta (TGF-beta). Therefore, we examined whether mulberry leaf aqueous fractions inhibit LOX-1 expression induced by proinflammatory stimuli. Pretreatment of cultured bovine aortic endothelial cells (BAECs) with mulberry leaf aqueous fractions inhibited TNF-alpha- and LPS-induced expression of LOX-1 at both protein and mRNA levels in a time- and concentration-dependent manner. In contrast, mulberry leaf aqueous fractions did not affect TGF-beta-induced LOX-1 expression. Furthermore, mulberry leaf aqueous fractions inhibited TNF-alpha-induced activation of nuclear factor-kappaB (NF-kappaB) and phosphorylation of inhibitory factor of NF-kappaB-alpha (IkappaB-alpha) in a time- and concentration-dependent fashion. Thus, mulberry leaf aqueous fractions suppress TNF-alpha- and LPS-induced LOX-1 gene expression, by inhibiting NF-kappaB activation.

Flavonoids from seabuckthorn protect endothelial cells (EA.hy926) from oxidized low-density lipoprotein induced injuries via regulation of LOX-1 and eNOS expression.

The present investigation was undertaken to determine the protective effects of flavonoids from seabuckthorn (FSBT), a traditional Chinese medicine, on endothelial cell line EA.hy926 injury induced by oxidized low-density lipoprotein (ox-LDL). Possible mechanisms were then explored. The effects of quercetin and isorhamnetin, 2 major components of FSBT, were examined as well. Indices such as cell viability, lactate dehydrogenase, nitric oxide (NO), superoxide dismutase, and superoxide were measured. Reverse transcription polymerase chain reaction, Western blot, and immunocytochemistry were employed to determine the endothelial constitutive NO synthase (eNOS) and lectinlike low-density lipoprotein receptor-1 (LOX-1) expression. Cell viability decreased significantly after 24 hours treatment with ox-LDL, accompanied with apparent secretion disorders such as NO reduction and lactate dehydrogenase increase. FSBT pretreatment could remarkably prevent both cell death and secretion disorders in a concentration-dependent manner. Besides, it was observed that ox-LDL triggered superoxide production and suppressed the superoxide dismutase activity, both of which could be prevented by FSBT pretreatment. Moreover, ox-LDL inhibited eNOS expression and increased LOX-1 expression, whereas FSBT pretreatment partly abolished these effects. Similar effects were obtained with quercetin and isorhamnetin, implying that they may contribute, at least in part, to the protective effects of FSBT. The data indicate that the protective effects of FSBT against ox-LDL induced endothelial cell injuries might derive from its antioxidant activity and its capability in modulating the expression of eNOS and LOX-1. And quercetin and isorhamnetin may contribute to these effects of FSBT.

Intervention of Tongxinluo capsule against vascular lesion of atherosclerosis and its effect on lectin-like oxidized low density lipoprotein receptor-1 expression in rabbits.

OBJECTIVE: To investigate the prevention by Tongxinluo capsule (TXL) of vascular lesions and its effect on the levels of protein and gene expression of lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) of vascular wall in rabbits with atherosclerosis (AS), and to explore its possible mechanism against AS. METHODS: AS models were established by feeding New Zealand white rabbits with high-cholesterol diet, and 24 immature rabbits were randomly divided into the control group, model group and treated group (treated with TXL capsule). The indexes of total cholesterol (TC) and low density lipoprotein (LDL) levels were measured at the 16th week. The intima thickness and the plaque area of abdominal aorta were quantitatively analyzed by pathological morphological analysis, the expression of macrophage and smooth muscle cell (SMC) in intima were detected by immunohistochemical method and histologic segments were stained by Hematoxilin-Eosin (HE) to identify the degree of atherosclerotic lesion in the model group and the prevention by TXL. The LOX-1 gene and protein expression in abdominal aorta was detected by semi-quantitative RT-PCR and immunohistochemistry, respectively. RESULTS: In the model group, the levels of TC and LDL were significantly elevated, aortic intima thickened extensively, the intima area enhanced, and macrophages expression increased; the levels of LOX-1 gene and protein expression was up-regulated in endothelium and neo-intima of the abdominal aorta. The treatment with TXL reduced blood lipids, attenuated arterial intimal proliferation, markedly inhibited the expression of macrophage and excessively expressed the level of LOX-1. CONCLUSION: TXL has an inhibitory effect on blood lipids, and it can prevent the occurrence of vascular lesion and cure its development, and its protection against AS was possibly associated with a crucial endothelial protective action through lowering the expression of LOX-1 in vascular walls.