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Atherosclerosis is an inflammatory disease that may cause severe heart disease and stroke. Current pharmacotherapy for atherosclerosis shows limited benefits. In the progression of atherosclerosis, monocyte adhesions and inflammatory macrophages play vital roles. However, precise regulations of inflammatory immune microenvironments in pathological tissues remain challenging. Here, we report an atherosclerotic plaque-targeted selenopeptide nanomedicine for inhibiting atherosclerosis progression by reducing monocyte adhesions and inflammation of macrophages. The targeted nanomedicine has 2.2-fold enhancement in atherosclerotic lesion accumulation. The oxidation-responsibility of selenopeptide enables eliminations of reactive oxygen species and specific release of anti-inflammatory drugs, thereby reducing inflammation responses of macrophages. Notably, we find the oxidative metabolite of selenopeptide, octadecyl selenite, can bind to P-selectin in a high affinity with a dissociation constant of 1.5 µM. This in situ generated active seleno-species further inhibit monocyte adhesions for anti-inflammation in synergy. With local regulations of monocyte adhesions and inflammations, the selenopeptide nanomedicine achieves 2.6-fold improvement in atherosclerotic plaque inhibition compared with simvastatin in the atherosclerosis mouse model. Meanwhile, the selenopeptide nanomedicine also displays excellent biological safety in both mice and rhesus monkeys. This study provides a safe and effective platform for regulating inflammatory immune microenvironments for inflammatory diseases such as atherosclerosis. [ABSTRACT FROM AUTHOR]

Atherosclerosis initiation is associated with a pro-inflammatory state of the endothelium. Quercetin is a flavonoid abundantly present in plant-based foods, with a possible impact on cardiovascular health. In this study, the effects of quercetin on lipopolysaccharide (LPS)-mediated endothelial inflammation and monocyte adhesion and migration, which are initial steps of the atherogenic process, are studied. Novel in vitro multicellular models simulating the intestinal-endothelial-monocytes/macrophages axis allowed to combine relevant intestinal flavonoid absorption, metabolism and efflux, and the consequent bioactivity towards peripheral endothelial cells. In this triple coculture, quercetin exposure decreased monocyte adhesion to and macrophage migration through an LPS-stressed endothelium, and this was associated with significantly lower levels of soluble vascular cell adhesion molecule-1 (sVCAM-1). Furthermore, quercetin decreased the pro-inflammatory cell environment upon LPS-induced endothelial activation, in terms of tumor necrosis factor- α (TNF-α), interleukin-6 (IL-6), interleukin-8 (IL-8), and sVCAM-1 expression. These findings highlight a mode-of-action by which quercetin may positively impact the initial states of atherosclerosis under more physiologically relevant conditions in terms of quercetin concentrations, metabolites, and intercellular crosstalk. [ABSTRACT FROM AUTHOR]

Objective and design: To determine the requirement of plasminogen activator inhibitor-1-knockout (PAI-1) for monocyte adhesion in animals and cells under diabetic conditions. Methods and subjects: Monocyte adhesion assay, enzyme-linked immunosorbent assay, and Western blotting were used in analyzing samples from PAI-1-knockout (PAI-1-KO) mice or cultured human umbilical vein endothelial cells (HUVEC). Treatments: Diabetes in PAI-1-KO and wild-type mice was induced by intraperitoneal injection of streptozotocin (STZ). HUVEC was transfected with short interference RNA (siRNA) against PAI-1, tumor necrosis factor-α (TNFα), or toll-like receptor (TLR4), and then was treated with glycated low-density lipoproteins (glyLDL). Results: The adhesion of monocytes to aortic intima was reduced in PAI-1-KO mice, which was associated with decreased levels of TNFα and monocyte chemotactic protein-1 (MCP-1) in plasma and cardiovascular tissue, and increased abundances of urokinase plasminogen activator (uPA) and uPA receptor (uPAR) in cardiovascular tissue compared to wild-type mice. Significant reductions in monocyte adhesion, inflammatory, and fibrinolytic regulators were detected in cardiovascular tissue or plasma in diabetic PAI-1-KO mice compared to wild-type diabetic mice. Transfection of PAI-1, TNFα or TLR4 siRNA to HUVEC inhibited glyLDL-induced monocyte adhesion to EC. PAI-1 siRNA inhibited the abundances of TLR4 and TNFα in EC. Conclusion: The findings suggest that PAI-1 is required for diabetes-induced monocyte adhesion via interactions with uPA/uPAR, and it also regulates TLR4 and TNFα expression in vascular EC. Inhibition of PAI-1 potentially reduces vascular inflammation under diabetic condition. [ABSTRACT FROM AUTHOR]

Endothelial activation with excessive recruitment and adhesion of immune cells plays a central role in the progression of sepsis. We established a microfluidic system to study the activation of human umbilical vein endothelial cells by conditioned medium containing plasma from lipopolysaccharide-stimulated whole blood or from septic blood and to investigate the effect of adsorption of inflammatory mediators on endothelial activation. Treatment of stimulated whole blood with polystyrene-divinylbenzene-based cytokine adsorbents (average pore sizes 15 or 30 nm) prior to passage over the endothelial layer resulted in significantly reduced endothelial cytokine and chemokine release, plasminogen activator inhibitor-1 secretion, adhesion molecule expression, and in diminished monocyte adhesion. Plasma samples from sepsis patients differed substantially in their potential to induce endothelial activation and monocyte adhesion despite their almost identical interleukin-6 and tumor necrosis factor-alpha levels. Pre-incubation of the plasma samples with a polystyrene-divinylbenzene-based adsorbent (30 nm average pore size) reduced endothelial intercellular adhesion molecule-1 expression to baseline levels, resulting in significantly diminished monocyte adhesion. Our data support the potential of porous polystyrene-divinylbenzene-based adsorbents to reduce endothelial activation under septic conditions by depletion of a broad range of inflammatory mediators. [ABSTRACT FROM AUTHOR]

Endothelial dysfunction has been implicated in the pathogenesis of atherosclerosis. Salvia miltiorrhiza (danshen) is a traditional Chinese medicine that has been effectively used to treat cardiovascular disease. Cryptotanshinone (CTS), a major lipophilic compound isolated from S. miltiorrhiza, has been reported to possess cardioprotective effects. However, the anti-atherogenic effects of CTS, particularly on tumor necrosis factor-α (TNF-α)-induced endothelial cell activation, are still unclear. This study aimed to determine the effect of CTS on TNF-α-induced increased endothelial permeability, monocyte adhesion, soluble intercellular adhesion molecule 1 (sICAM-1), soluble vascular cell adhesion molecule 1 (sVCAM-1), monocyte chemoattractant protein 1 (MCP-1) and impaired nitric oxide production in human umbilical vein endothelial cells (HUVECs), all of which are early events occurring in atherogenesis. We showed that CTS significantly suppressed TNF-α-induced increased endothelial permeability, monocyte adhesion, sICAM-1, sVCAM-1 and MCP-1, and restored nitric oxide production. These observations suggest that CTS possesses anti-inflammatory properties and could be a promising treatment for the prevention of cytokine-induced early atherogenesis. [ABSTRACT FROM AUTHOR]

Numerous clinical studies have highlighted the pivotal role Dickkopf (DKK) 1 plays in atherosclerosis, but the underlying mechanisms remain unknown. The present study was designed to explore the contribution of DKK1 to the development of atherosclerosis under oscillatory shear stress. Oscillatory shear stress applied to endothelial cells induced DKK1 expression, which peaked at 6 h. siRNA knockdown or silencing DKK1 by lentiviral gene delivery counteracted the increased monocyte adhesion and impaired endothelial tight junction induced by oscillatory shear stress, thereby attenuating atherogenesis in ApoE−/− mice. As well, activation of endothelial proteinase-activated receptor 1 (PAR1) and its downstream transcription factor, cAMP response element-binding protein (CREB), was critical to the increased expression of DKK1 under oscillatory shear stress. We provide evidence that DKK1 contributes to the development of atherosclerosis under conditions of oscillatory shear stress. A better understanding of the role played by DKK1 in atherogenesis may provide clinicians with opportunities to prevent atherosclerosis. Key message: [ABSTRACT FROM AUTHOR]

The leucine-rich repeat kinase 2 (LRRK2) gene was discovered to encode a member of an evolutionarily conserved family of proteins marked by GTPase domains usually in combination with kinase domains. Missense mutations in both the kinase and GTPase domains in LRRK2 have been found to cause late-onset Parkinson's disease (PD). In this study, we investigated the effects of the LRRK2 on endothelial inflammation. We first demonstrated that the LRRK2 is expressed in endothelial cells. We also report here that IL-1β can possibly increase LRRK2 expression in human umbilical vein endothelial cells (HUVECs). Wild-type LRRK2 (LRRK2) expression induces expression of vascular cell adhesion molecule 1 (VCAM-1) which is further exacerbated in cells expressing PD-associated LRRK2 G2019S mutants (LRRK2). Importantly, induction of VCAM-1 is almost completely blocked in cells expressing the GTP-binding-deficient mutant K1347A of LRRK2 (LRRK2). In addition, overexpression of LRRK2 and LRRK2 were found to cause an increase in monocyte attachment to endothelial cells. Mechanistically, we found that LRRK2 increases the transcriptional activity of nuclear factor κB (NF-κB) by increasing phosphorylation levels of IκBα. These findings suggest that inhibition of LRRK2 kinase activity may be a potential target for treatment of endothelial dysfunction. [ABSTRACT FROM AUTHOR]

The objective of this study was to investigate the effect of rhein lysinate (RHL) on monocyte adhesion and its mechanism. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was used to determine the growth inhibition by drugs. The monocyte chemoattractant protein (MCP)-1 levels were assayed using MCP-1 ELISA. The expression of proteins was detected by Western blotting analysis. The results indicated that RHL inhibited monocyte adhesion in a dose- and time-dependent manner. RHL (<20 μmol/L) and lipopolysaccharide (LPS) had no effect on viability of human umbilical vein endothelial cells. Therefore, 20 μmol/L RHL was selected for this study. RHL inhibited secretion of MCP-1 induced by LPS and expression of intercellular adhesion molecule (ICAM)-1 and vascular cell adhesion molecule (VCAM)-1. In the meantime, both RHL and p38 inhibitor (SB203580) inhibited phosphorylation of p38 and mitogen-activated protein kinase-activated protein kinase-2 (MAPKAPK-2) and transcription and expression of ICAM-1 and VCAM-1. In conclusion, RHL inhibits the transcription and expression of ICAM-1 and VCAM-1 by the p38/MAPKAPK-2 signaling pathway, and the effect of RHL on transcription and expression of ICAM-1 and VCAM-1 is similar to p38 inhibitor. RHL could be a prophylactic drug for atherosclerosis. [ABSTRACT FROM AUTHOR]

Sparstolonin B (SsnB) is an isocoumarin compound isolated from the tubers of both Sparganium stoloniferum and Scirpus yagara. We previously demonstrated that SsnB blocked the Toll-like receptor (TLR) 2- and TLR4-triggered inflammatory signaling in macrophages by inhibiting the recruitment of MyD88 to the TIR domains of TLR2 and TLR4. The present study was designed to examine the effects of SsnB on vascular inflammatory responses in human umbilical vein endothelial cells (HUVECs) challenged by lipopolysaccharide (LPS, a TLR4 ligand). We found that SsnB dose-dependently attenuated the LPS-induced expression of interleukin (IL)-1β and monocyte chemoattractant protein 1 both at the transcription and translation levels in HUVEC. LPS-induced endothelial cell adhesion molecules, intercellular adhesion molecular-1 and vascular cell adhesion molecule-1 expressions were also reduced by treatment with SsnB. In addition, co-incubation with SsnB attenuated THP-1 monocyte adhesion to LPS-activated HUVECs. Furthermore, SsnB efficiently suppressed LPS-induced phosphorylation of extracellular -signal-regulated kinase (Erk1/2) and Akt in HUVECs. These findings show that SsnB can suppress endothelial cell inflammation, suggesting that SsnB might be suitable for development as a therapeutic agent for inflammatory cardiovascular disease. [ABSTRACT FROM AUTHOR]

Glycolipid biosurfactant (GLB) from Rhodococcus ruber IEGM 231 was found to stimulate tumor necrosis factor-α (TNF-α), interleukin (IL) -1β and IL-6 production when applied as an ultrasonic emulsion to the adherent human peripheral blood monocyte culture. However, a lack of cytokine-stimulating activity was registered with the GLB applied as a hydrophobic film coating in 24-well culture plates, indicating that it may have been due to its inhibitory effect on monocyte adhesion. The mode of GLB application may therefore play an important role in in vitro assay of immunostimulatory activity of this compound as well as other bacterial glycolipids. Additionally, GLB from R. ruber displayed no cytotoxicity against human lymphocytes and therefore could be proposed as a potential immunomodulating and antitumor agent. [ABSTRACT FROM AUTHOR]

ims/hypothesis: Severe hypoglycaemia associated with diabetes management is a potential risk for cardiovascular diseases. However, the effect and mechanism of hypoglycaemia on the progression of atherosclerosis remains largely unknown. As a first step towards elucidating the above, we investigated the effect of hypoglycaemia on monocyte-endothelial interaction. Methods: Insulin was injected intraperitoneally once every 3 days for 5 weeks in Goto-Kakizaki rats, a non-obese rat model of type 2 diabetes. We counted the number of monocytes adherent to the endothelium of thoracic aorta as an index of early atherosclerogenesis. Cultured HUVEC were used to investigate the mechanism of action. Results: Insulin treatment increased the number of monocytes adherent to the vascular endothelium. This increase was abrogated by injection of glucose with insulin. Amosulalol, an α-1 and β-adrenoreceptor antagonist, suppressed monocyte adhesion to endothelium and levels of adhesion molecules (intercellular adhesion molecule-1 and vascular cell adhesion molecule-1) in the endothelial surface, which had been enhanced by insulin-induced hypoglycaemia. In HUVEC, adrenaline (epinephrine) significantly increased nuclear translocation of nuclear factor-κB (NF-κB) p65 and levels of adhesion molecules, effects that were abrogated following addition of SQ22536, a specific adenyl cyclase inhibitor. Conclusions/interpretation: Our data indicate that repetitive hypoglycaemia induced by insulin enhanced monocyte adhesion to endothelial cells in Goto-Kakizaki rat aorta through enhanced adrenaline activity and that the latter stimulated intracellular cAMP, leading to nuclear translocation of NF-κB with subsequent production of adhesion molecules in endothelial cells. [ABSTRACT FROM AUTHOR]

Shear stress is an important factor in the onset and progression of atherosclerosis. High and unidirectional laminar stress is seen as protective, while low and oscillatory shear stress is considered pro-inflammatory and pro-atherogenic. The mechanosensitive response of endothelial cells is governed by a complex system of genes, proteins, and signals that operate at distinctly different time scales. We propose a dynamic mathematical model that quantitatively describes this mechanosensing system and permits novel insights into its functioning. The model, the first of its kind, is constructed within the guidelines of Biochemical Systems Theory and accounts for different time scales by means of approximated delays. Parameter values are obtained directly from biochemical observations in an ad hoc fashion. The model reflects most documented observations well and leads to a number of predictions and novel hypotheses. In particular, it demonstrates the crucial role of Bone Morphogenic Protein 4 and p47phox-dependent NADPH oxidases in endothelial inflammation. [ABSTRACT FROM AUTHOR]

Cell adhesion molecules play a pivotal role in chronic inflammation and pathological angiogenesis. In the present study, we investigated the inhibitory effects of clotrimazole (CLT) on tumor necrosis factor (TNF)-α-induced changes in adhesion molecule expression. CLT dose-dependently inhibited monocyte chemoattractant protein-1 (MCP-1), intercellular cell adhesion molecule-1 (ICAM-1), and vascular cell adhesion molecule-1 (VCAM-1) expressions in TNF-α-stimulated HT29 colonic epithelial cells. This inhibitory action of CLT correlated with a significant reduction in TNF-α-induced adhesion of monocytes to HT29 cells, which was comparable to the inhibitory effects of anti-ICAM-1 and VCAM-1 monoclonal antibodies on monocyte-epithelial adhesion. These inhibitory actions of CLT were, at least in part, attributable to the inhibition of redox sensitive NF-κB activation, as CLT inhibited TNF-α-induced ROS generation as well as NF-κB nuclear translocation and activation in HT29 cells. Furthermore, the inhibition of TNF-α-induced monocyte adhesion was also mimicked by the specific NF-κB inhibitor, pyrrolidine dithiocarbamate (PDTC). Inflammatory mediators including TNF-α have known to promote angiogenesis, which in turn further contributes to inflammatory pathology. Therefore, we additionally evaluated whether CLT modulates TNF-α-induced angiogenesis using in vivo chick chorioallantoic membrane (CAM) assay. The CAM assay showed that CLT dose-dependently attenuated TNF-α-induced angiogenesis, and the effect was correlated with decreased inflammation of the CAM tissue. In conclusion, our results suggest that CLT can inhibit TNF-α-triggered expression of adhesion molecules, ICAM-1 and VCAM-1, and angiogenesis during inflammation. [ABSTRACT FROM AUTHOR]

Many epidemiological studies predict a role for homocysteine (HCys) in cardiovascular disease occurrence, progression, and risk factors. In vitro studies demonstrated that HCys is an atherogenic determinant that promotes oxidant stress, inflammation, endothelial dysfunction and cell proliferation. This study originally attempted to examine the mechanism by which exposure of endothelial cells to HCys (0–250 µM) initiates inflammatory reaction and oxidative stress, by (i) investigating whether physiological and pathophysiological concentrations of HCys exhibit a prooxidative activity in vitro, (ii) examining the interaction of monocyte adhesion (Mono Mac 6) to monolayers of human microvascular endothelial cells (HMEC-1) exposed to different HCys concentrations, and (iii) examining if adherent monocytes increase reactive oxygen species either in endothelial cells or in monocytes themselves. However, our results demonstrate that HCys had neither prooxidative nor cytotoxic effects on endothelial cells. Only a moderate time- and concentration-dependent increase in monocyte adhesion up to 28.3 ± 5.5% was achieved relative to control after 4 h of HCys stimulation. This effect was accompanied by an increased VCAM and ICAM-1 mRNA expression. This “proinflammatory” effect appeared also when HMEC-1 cells were incubated with cysteine or glutathione at the concentration range 0–250 µM, demonstrating a non-specific rather than a specific HCys effect. In addition, adherent monocytes did not increase ROS formation neither in endothelial cells nor in monocytes themselves, indicating no direct or indirect cytotoxic or prooxidative effects of HCys. [ABSTRACT FROM AUTHOR]