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Introduction To investigate the role of placental extracellular vesicles (EVs), especially in pathological pregnancy, the use of freshly isolated EVs is often limited due to the sporadic and unpredictable availability of placental samples. Therefore, it is important to understand and use optimised storage conditions for placental EVs. In this study, we investigated different conditions for the short-term storage of placental micro- and nano-EVs and examined their biological activity. Methods Placental EVs were collected from first trimester placentae. EVs were suspended in PBS and aliquoted, and then stored for up to 14 days at room temperature, 4 °C or −20 °C. Total protein and DNA levels were measured at various time points. The ability of stored placental EVs to alter endothelial cell activation was quantified by monocyte adhesion assays. Results There was no difference in the concentration of placental micro- or nano-EVs between each time point, when stored at either room temperature or 4 °C. However, there was a significant loss of placental EVs after storage at −20 °C. There was no difference in protein or DNA levels of placental EVs when stored at either room temperature or 4 °C. Biological activity of placental EVs was retained for up to 14 days at either room temperature or 4 °C measured by monocyte adhesion assays. Discussion We have shown that placental micro- and nano-EVs are stable and retain biological activities following storage in PBS or media for 14 days at either room temperature or 4 °C.

One of the earliest events in the development of atherosclerosis is endothelial activation, which is estimated in vitro at the functional level by quantifying monocyte adhesion. This involves the incubation of fluorescently labeled monocytes on top of cultured endothelial cells and quantifying the number of adhered monocytes. Currently, the quantification of adhered monocytes is done using microscopy or by lysing the cells and estimating the fluorescence. Here we present a novel flow cytometry-based method for the quantification of monocyte adhesion. This method could quantify the average number of monocytes adhered to a single endothelial cell after monocyte adhesion assay, and was also sensitive to the level of activation of endothelial cells. Flow cytometry-based quantification requires less time and effort compared with microscopy-based quantification.

Background Ficus deltoidea (FD) has been shown to have antidiabetic, anti-inflammatory, antinociceptive and antioxidant properties. However, its effects on key events in the pathogenesis of atherosclerosis are unknown. Aim To investigate the endothelial activation, inflammation, monocyte-endothelial cell binding and oxidative stress effects of four FD varieties. Methods Human coronary artery endothelial cells (HCAEC) were incubated with different concentrations of aqueous ethanolic extracts of FD var. trengganuensis (FDT), var. kunstleri (FDK), var. deltoidea (FDD) and var. intermedia (FDI), together with LPS. Protein and gene expression of vascular cell adhesion molecule-1 (VCAM-1), intercellular cell adhesion molecule-1 (ICAM-1), endothelial-leukocyte adhesion molecule-1 (E-selectin), interleukin-6 (IL-6), Nuclear factor-κB (NF-κB) p50 and p65 and endothelial nitric oxide synthase (eNOS) were measured using ELISA and QuantiGene plex, respectively. Adhesion of monocyte to HCAEC and formation of reactive oxygen species (ROS) were detected by Rose Bengal staining and 2′-7′-dichlorofluorescein diacetate (DCFH-DA) assay. Results FDK exhibited the highest inhibition of biomarkers in relation to endothelial activation and inflammation, second in reducing monocyte binding (17.3%) compared to other varieties. FDK (25.6%) was also the most potent at decreasing ROS production. Conclusion FD has anti-atherogenic effects, possibly mediated by NF-κB and eNOS pathways; with FDK being the most potent variety. It is potentially beneficial in mitigating atherogenesis.

Resveratrol, a natural compound in grapes and red wine, has drawn attention due to potential cardiovascular-related health benefits. However, its effect on vascular inflammation at physiologically achievable concentrations is largely unknown. In this study, resveratrol in concentrations as low as 1 μm suppressed TNF-α-induced monocyte adhesion to human EA.hy926 endothelial cells (ECs), a key event in the initiation and development of atherosclerosis. Low concentrations of resveratrol (0.25–2 μm) also significantly attenuated TNF-α-stimulated mRNA expressions of MCP-1/CCL2 and ICAM-1, which are vital mediators of EC-monocyte adhesion molecules and cytokines for cardiovascular plaque formation. Additionally, resveratrol diminished TNF-α-induced IκB-α degradation and subsequent nuclear translocation of NF-κB p65 in ECs. In the animal study, resveratrol supplementation in diet significantly diminished TNF-α-induced increases in circulating levels of adhesion molecules and cytokines, monocyte adhesion to mouse aortic ECs, F4/80-positive macrophages and VCAM-1 expression in mice aortas and restored the disruption in aortic elastin fiber caused by TNF-α treatment. The animal study also confirmed that resveratrol blocks the activation of NF-κB In Vivo. In conclusion, resveratrol at physiologically achievable concentrations displayed protective effects against TNF-α-induced vascular endothelial inflammation in vitro and In Vivo. The ability of resveratrol in reducing inflammation may be associated with its role as a down-regulator of the NF-κB pathway. Published version

Osteoarthritis (OA) is characterized by the infiltration and adhesion of monocyte into the joint synovium. Vascular cell adhesion molecule 1 (VCAM-1) is a critical cell adhesion molecule that controls monocyte motility during OA progression. Cordycerebroside A, a cerebroside compound isolated from Cordyceps militaris, inhibits the production of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in synovial macrophages, but has not yet been investigated in OA. Gene Expression Omnibus (GEO) dataset analysis revealed higher levels of VCAM-1 and CD11b (a monocyte marker) in OA synovial tissue compared with normal healthy tissue. The same results were observed in anterior cruciate ligament transaction (ACLT)-induced OA in rats compared with normal healthy controls. Cordycerebroside A markedly suppressed VCAM-1 expression and monocyte adhesion in human OA synovial fibroblasts. The MEK, ERK and AP-1 signaling cascades regulated cordycerebroside A-induced inhibition of VCAM-1 production. Thus, cordycerebroside A is a promising agent for the treatment of OA.

Background and Purpose: GPR55 is a G protein-coupled receptor that recognizes several lipid molecules. GPR55 expression in human monocytes and its proinflammatory role lead us to investigate the role of GPR55 in monocyte adhesion and atherosclerosis development. Experimental Approach: We investigated monocyte adhesion in human THP-1 monocytes and atherosclerosis development in ApoE-/- mice by using O-1602 (a potent agonist of GPR55), CID16020046 (a specific GPR55 antagonist), and a high-fat diet-induced atherosclerosis model. Key Results: In human THP-1 monocytes, treatment with O-1602 significantly increased monocyte adhesion to human umbilical vein endothelial cells (HUVECs), and the O-1602-induced adhesion was inhibited by treatment with CID16020046. O-1602 induced the expression of Mac-1 adhesion molecules, whereas CID16020046 inhibited this induction. Analysis of the promoter region of Mac-1 elucidated the binding sites of AP-1 and NF-κB between nucleotides -750 and -503 as GPR55 responsive elements. Furthermore, O-1602 induction of Mac-1 through AP-1 and NF-B was found to be dependent on the signaling components of GPR55, that is, Gq protein, Ca2+, CaMKK, and PI3K. In an in vivo study of high-fat diet-induced atherosclerosis in ApoE-/- mice, administration of CID16020046 ameliorated atherosclerosis development. These results suggest that high-fat diet-induced GPR55 activation leads to adhesion of monocytes to endothelial cells via induction of Mac-1, and CID16020046 blockage of GPR55 could suppress monocyte adhesion to vascular endothelial cells through suppression of Mac-1 expression, leading to protection against the development of atherosclerosis. Conclusions: This report suggests that GPR55 may be a therapeutic target for atherosclerosis development.

Although various physiological activities of compounds obtained from Paeonia lactiflora have been reported, the effects of P. lactiflora extract (PLE) on early atherosclerosis remain unclear. Therefore, in this study, we investigated the in vitro and in vivo antiatherosclerosis and in vitro antioxidant effects of PLE and its compounds. PLE suppresses the tumor necrosis factor (TNF)-α-induced capacity of THP-1 cells to adhere to human umbilical vein endothelial cells (HUVECs), vascular cell adhesion molecule (VCAM)-1 expression, and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signaling in HUVECs. PLE also suppresses TNF-α-induced nuclear translocation of NF-κB p65 from cytosol as well as the enhanced TNFA and C-C motif chemokine ligand 2 (CCL2) mRNA expression in HUVECs. We identified and quantified the following PLE compounds using high-performance liquid chromatography with diode array detection: methyl gallate, oxypaeoniflorin, catechin, albiflorin, paeoniflorin, benzoic acid, benzoylpaeoniflorin, and paeonol. Among these, methyl gallate had the strongest inhibitory effect on monocyte adherence to TNF-α-induced HUVECs and the VCAM-1 expression. Reverse transcriptase real-time quantitative polymerase chain reaction showed that PLE compounds had a dissimilar inhibition effect on TNF-α-induced mRNA expression levels of CCL2, TNFA, and IL6 in HUVECs. Except for paeonol, the compounds inhibited lipopolysaccharide (LPS)-induced reactive oxygen species production in RAW264.7 cells. In vivo, oral administration of PLE improved TNF-α-induced macrophage infiltration to the vascular endothelium and expression of VCAM-1, as well as IL6 and TNFA gene expression in the main artery of mice. PLE could be useful as a nutraceutical material against early atherosclerosis via the combined effects of its components.

© 2021 by the authors., Calcific aortic valve disease (CAVD) is an athero-inflammatory process. Growing evidence supports the inflammation-driven calcification model, mediated by cytokines such as interferons (IFNs) and tumor necrosis factor (TNF)-α. Our goal was investigating IFNs’ effects in human aortic valve endothelial cells (VEC) and the potential differences between aortic (aVEC) and ventricular (vVEC) side cells. The endothelial phenotype was analyzed by Western blot, qPCR, ELISA, monocyte adhesion, and migration assays. In mixed VEC populations, IFNs promoted the activation of signal transducers and activators of transcription-1 and nuclear factor-κB, and the subsequent up-regulation of pro-inflammatory molecules. Side-specific VEC were activated with IFN-γ and TNF-α in an orbital shaker flow system. TNF-α, but not IFN-γ, induced hypoxia-inducible factor (HIF)-1α stabilization or endothelial nitric oxide synthase downregulation. Additionally, IFN-γ inhibited TNF-α–induced migration of aVEC. Also, IFN-γ triggered cytokine secretion and adhesion molecule expression in aVEC and vVEC. Finally, aVEC were more prone to cytokine-mediated monocyte adhesion under multiaxial flow conditions as compared with uniaxial flow. In conclusion, IFNs promote inflammation and reduce TNF-α–mediated migration in human VEC. Moreover, monocyte adhesion was higher in inflamed aVEC sheared under multiaxial flow, which may be relevant to understanding the initial stages of CAVD., This research was funded by grants from Spanish Ministry of Economy and Competitiveness, co-funded by the European Social Fund FEDER (SAF2013-44521-R, SAF2017-83079-R, PID2020- 113751RB-I00); Junta de Castilla y León (BIO/VA47/14, BIO/VA36/15, CSI035P17, GRS1432/A/16, GRS2205/A/2020, VA175P20, and Programa Estratégico IBGM-Escalera de Excelencia Ref. CLU2019-02); Fundación Domingo Martínez; and the Instituto de Salud Carlos III (Spanish Ministry of Health PI14/00022, CIBERCV CB16/11/00260). I.P. and T.S.B., PhD fellows from Valladolid University-Banco de Santander. A.C. was funded by the Magdi Yacoub Institute.

Tobacco smoking and hemodynamic forces are key stimuli for the development of endothelial dysfunction. As an alternative to smoking, next generation tobacco and nicotine products (NGP) are now widely used. However, little is known about their potential pro-inflammatory and atherogenic effects on the endothelium. In this study, we analyzed key parameters of endothelial function after exposure to aqueous smoke extracts (AqE) of a heated tobacco product (HTP), an electronic cigarette (e-cig), a conventional cigarette (3R4F) and pure nicotine. All experiments were performed under atheroprotective high laminar or atherogenic low flow with primary human endothelial cells. Treatment with 3R4F, but not alternative smoking products, reduced endothelial cell viability and wound healing capability via the PI3K/AKT/eNOS(NOS3) pathway. Laminar flow delayed detrimental effects on cell viability by 3R4F treatment. 3R4F stimulation led to activation of NRF2 antioxidant defense system at nicotine concentrations ≥0.56 μg/ml and increased expression of its target genes HMOX1 and NQO1. Treatment with HTP revealed an induction of HMOX1 and NQO1 at dosages with ≥1.68 μg/ml nicotine, whereas e-cig and nicotine exposure had no impact. Analyses of pro-inflammatory genes revealed an increased ICAM1 expression under 3R4F treatment. 3R4F reduced VCAM1 expression in a dose-dependent manner; HTP treatment had similar but milder effects; e-cig and nicotine treatment had no impact. SELE expression was induced by 3R4F under static conditions. High laminar flow prevented this upregulation. Stimulation with laminar flow led to downregulation of CCL2 (MCP-1). From this downregulated level, only 3R4F increased CCL2 expression at higher concentrations. Finally, under static conditions, all components increased adhesion of monocytes to endothelial cells. Interestingly, only stimulation with 3R4F revealed increased monocyte adhesion under atherosclerosis-prone low flow. In conclusion, all product categories activated anti-oxidative or pro-inflammatory patterns. NGP responses were typically lower than in 3R4F exposed cells. Also, 3R4F stimulation led to an impaired endothelial wound healing and induced a pro-inflammatory phenotype compared to NGP treatment., Graphical abstract Image 1, Highlights • 3R4F, but not NGP and nicotine, impair endothelial cell viability and wound healing. • All tested product categories induce anti-oxidative enzymes and adhesion molecules in HUVEC. • Only 3R4F increases monocyte adhesion to endothelial cells under low laminar flow. • Protective effects of high laminar flow counteract with deleterious effects of smoking.

Human monocytes have been classified into three distinct groups, classical (anti-inflammatory; CD14+/CD16−), nonclassical (patrolling; CD14+/CD16++), and intermediate (proinflammatory; CD14++/CD16+). Adhesion of nonclassical/intermediate monocytes with the endothelium is important for innate immunity, and also vascular inflammatory disease. However, there is an incomplete understanding of the mechanisms that regulate CD16+ versus CD16− monocyte adhesion to the inflamed endothelium. Here, we tested the hypothesis that a high-mannose (HM) N-glycoform of intercellular adhesion molecule-1 (ICAM-1) on the endothelium mediates the selective recruitment of CD16+ monocytes. Using TNF-α treatment of human umbilical vein endothelial cells (HUVECs), and using proximity ligation assay for detecting proximity of specific N-glycans and ICAM-1, we show that TNF-α induces HM-ICAM-1 formation on the endothelial surface in a time-dependent manner. We next measured CD16− or CD16+ monocyte rolling and adhesion to TNF-α-treated HUVECs in which HM- or hybrid ICAM-1 N-glycoforms were generated using the α-mannosidase class I and II inhibitors, kifunensine and swainsonine, respectively. Expression of HM-ICAM-1 selectively enhanced CD16+ monocyte adhesion under flow with no effect on CD16− monocytes noted. CD16+ monocyte adhesion was abrogated by blocking either HM epitopes or ICAM-1. A critical role for HM-ICAM-1 in mediating CD16+ monocyte rolling and adhesion was confirmed using COS-1 cells engineered to express HM or complex ICAM-1 N-glycoforms. These data suggest that HM-ICAM-1 selectively recruits nonclassical/intermediate CD16+ monocytes to the activated endothelium. NEW & NOTEWORTHY Monocyte subsets have been associated with cardiovascular disease, yet it is unknown how different subsets are recruited to the endothelium. This study demonstrates the formation of distinct ICAM-1 N-glycoforms in the activated endothelium and reveals a key role for high mannose ICAM-1 in mediating proinflammatory CD16+ monocyte adhesion. Presented data identify roles for endothelial N-glycans in recruiting specific monocyte subsets during inflammation.

Objective Atherosclerosis is a major cause of cardiovascular disease. Monocyte-endothelial cell interactions are partly mediated by expression of monocyte CX3CR1 and endothelial cell fractalkine (CX3CL1). Interrupting the interaction between this ligand–receptor pair should reduce monocyte binding to the endothelial wall and reduce atherosclerosis. We sought to reduce atherosclerosis by preventing monocyte-endothelial cell interactions through use of a long-acting CX3CR1 agonist. Methods In this study, the chemokine domain of CX3CL1 was fused to the mouse Fc region to generate a long-acting soluble form of CX3CL1 suitable for chronic studies. CX3CL1-Fc or saline was injected twice a week (30 mg/kg) for 4 months into Ldlr knockout (KO) mice on an atherogenic western diet. Results CX3CL1-Fc-treated Ldlr KO mice showed decreased en face aortic lesion surface area and reduced aortic root lesion size with decreased necrotic core area. Flow cytometry analyses of CX3CL1-Fc-treated aortic wall cell digests revealed a decrease in M1-like polarized macrophages and T cells. Moreover, CX3CL1-Fc administration reduced diet-induced atherosclerosis after switching from an atherogenic to a normal chow diet. In vitro monocyte adhesion studies revealed that CX3CL1-Fc treatment caused fewer monocytes to adhere to a human umbilical vein endothelial cell monolayer. Furthermore, a dorsal window chamber model demonstrated that CX3CL1-Fc treatment decreased in vivo leukocyte adhesion and rolling in live capillaries after short-term ischemia-reperfusion. Conclusion These results indicate that CX3CL1-Fc can inhibit monocyte/endothelial cell adhesion as well as reduce atherosclerosis., Highlights • Long-acting FKN-Fc reduced atherosclerosis in LDLR KO mice in a prevention model. • FKN-Fc administration accelerated diet-induced regression of established atherosclerosis. • Monocyte adhesion in vitro and in vivo is reduced in the presence of FKN-Fc.

Inflammation associated endothelial dysfunction represents a pivotal contributor to atherosclerosis. Increasingly evidence has demonstrated that interleukin 1 receptor (IL1-R) / toll-like receptor (TLR) signaling participated in the development of atherosclerosis. Previous studies indicated the therapeutic potential of anti-inflammatory therapy in anti-atherosclerosis. The present study examined the effect of IL-1R-associated kinase 1 and 4 inhibitors (IRAK1/4i) in regulating endothelial dysfunction. IRAK1/4i showed little endothelial toxicity at concentrations from 1 to 10 μM. Inhibition of IRAK1/4 alleviated endothelial activation induced by LPS in vitro evidenced by attenuated monocyte adhesion to the endothelium. Mechanistically, blockade of IRAK1/4 ameliorated the transcriptional activity of NF-κB. Taken together, our findings demonstrated that dual inhibition of IRAK1 and IRAK4 attenuates endothelial dysfunction, suggesting pharmaceutical inhibition of IRAK1/4 might be a potential strategy to combat endothelial dysfunction and atherosclerosis.

Atherosclerosis is a chronic inflammatory disease and the underlying cause of most cardiovascular diseases. Interleukin (IL)-1β facilitates early atherogenic lesion formation by increasing monocyte adhesion to endothelial cells via upregulation of adhesion molecules, including intercellular adhesion molecule-1 (ICAM-1). MicroRNAs (miRNAs) have been shown to be associated with inflammatory conditions in the vascular system. The expression of circulating miR-1914–5p is reportedly downregulated in patients with cardiovascular diseases. However, the role of miR-1914–5p downregulation in IL-1β–induced endothelial cell dysfunction and the effect of miR-1914–5p on lesion formation remain unclear. Therefore, we investigated whether miR-1914–5p is associated with monocyte adhesion in human endothelial cells. IL-1β decreased miR-1914–5p expression in EA.hy926 cells. In addition, miR-1914–5p depletion enhanced ICAM-1 expression and monocyte adhesion in EA.hy926 cells. Moreover, miR-1914–5p mimic suppressed monocyte adhesion and ICAM-1 expression induced by IL-1β in endothelial cells. These results suggest that suppression of miR-1914–5p expression by IL-1β may be an important regulator in mediating monocyte adhesion in endothelial cells. Further investigation of miR-1914–5p may lead to the development of novel therapeutic strategies for atherosclerosis., Graphical abstract Image 1, Highlights • IL-1β enhanced cell adhesion in human endothelial cells. • IL-1β decreased miR-1914–5p expression in human endothelial cells. • miR-1914–5p depletion enhanced ICAM-1 expression and monocyte adhesion. • Exogenous miR-1914–5p attenuated ICAM-1 expression and monocyte adhesion. • Regulating miR-1914–5p expression via IL-1β may aid in preventing atherosclerosis.

Background Increasing evidence showed that carbamylated lipoprotein accelerated atherosclerosis. However, whether such modification of high-density lipoprotein (HDL) particles alters in type 2 diabetes mellitus (T2DM) patients and facilitates vascular complications remains unclear. We aimed to investigate the alteration of the carbamylation in HDL among T2DM patients and clarify its potential role in atherogenesis. Methods A total of 148 consecutive T2DM patients undergoning angiography and 40 age- and gender-matched control subjects were included. HDL was isolated from plasma samples, and the concentration of HDL carbamyl-lysine (HDL-CBL) was measured. Furthermore, the HDL from subjects and in-vitro carbamylated HDL (C-HDL) was incubated with endothelial cells and monocyte to endothelial cell adhesion. Adhesion molecule expression and signaling pathway were detected. Results Compared with the control group, the HDL-CBL level was remarkably increased in T2DM patients (6.13 ± 1.94 vs 12.00 ± 4.06 (ng/mg), P P = 0.001). Multivariate logistic regression analysis demonstrated that higher HDL-CBL level was independently associated with a higher prevalence of CAD in diabetic patients after adjusting for established cofounders (adjusted odds ratio 1.174, 95% confidence Interval 1.045–1.319, p = 0.017). HDL from diabetic patients with CAD enhanced greater monocyte adhesion than that from the non-CAD or the control group (P Conclusions Our study identified elevated carbamylation modification of HDL from T2DM patients, especially in those with concomitant CAD. We also evidenced that C-HDL enhanced monocyte to endothelial cell adhesion, indicating a potential pro-atherogenic role of C-HDL in atherosclerosis among T2DM patients. Trial registrationhttps://register.clinicaltrials.gov, NCT04390711 Registered on 14 May 2020; Retrospectively registered

The initiation of atherosclerosis (AS) induced by dyslipidemia is accompanied by endothelial dysfunction, including decreased healing ability and increased recruitment of monocytes. Studies showed ginsenoside Rg3 has potential to treat diseases associated with endothelial dysfunction which can protects against antineoplastic drugs induced cardiotoxicity by repairing endothelial function, while the effect and mechanism of Rg3 on dyslipidemia induced endothelial dysfunction and AS are not clear. Therefore, we investigated the effects of Rg3 on oxidized low-density lipoprotein (ox-LDL) induced human umbilical vein endothelial cells (HUVECs) dysfunction and high-fat diets (HFD) induced atherosclerosis in ApoE-/- mice, as well as the mechanism. For in vitro assay, Rg3 enhanced healing of HUVECs and inhibited human monocytes (THP-1) adhesion to HUVECs disturbed by ox-LDL, down-regulated focal adhesion kinase (FAK)-mediated expression of vascular cell adhesion molecule 1 (VCAM-1) and intercellular adhesion molecule 1 (ICAM-1); restrained the FAK-mediated non-adherent dependent pathway containing matrix metalloproteinase (MMP)-2/9 expression, activation of nuclear factor-kappa B (NF-κB), high mRNA levels of monocyte chemotactic protein 1 (MCP-1) and interleukin 6 (IL-6), besides Rg3 up-regulated peroxisome proliferators-activated receptor γ (PPARγ) in ox-LDL-stimulated HUVECs. GW9662, the PPARγ-specific inhibitor, can repressed the effects of Rg3 on ox-LDL-stimulated HUVECs. For in vivo assay, Rg3 significantly reduced atherosclerotic pathological changes in ApoE-/- mice fed with HFD, up-regulated PPARγ, and inhibited activation FAK in aorta, thus inhibited expression of VCAM-1, ICAM-1 in intima. We conclude that Rg3 may protect endothelial cells and inhibit atherosclerosis by up-regulating PPARγ via repressing FAK-mediated pathways, indicating that Rg3 have good potential in preventing dyslipidemia induced atherosclerosis.

Disruption of the blood-brain-barrier (BBB), a crucial event for the entry of inflammatory cells into brain, is a prerequisite for the pathogenesis of many cerebral diseases. Oxidative stress is one of the well-known factors that accounts for the leakage of the BBB, which can be alleviated by the activation of the nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway. Isoastragaloside I (ISOI) is a cycloartane glycoside isolated from Radix Astragali, a clinical widely used traditional Chinese medicine. In the present study, the effect of ISOI on LPS-induced bEnd.3 cells was assessed and the underlying molecular mechanisms were investigated. Our results showed that ISOI pre-treatment inhibited the reduction of TEER, prevented the increase of NaF extravasation and ROS production, and rescued the down-regulated tight-junction (TJ) protein level in bEnd.3 cells stimulated with LPS. Meanwhile, it significantly activated Nrf2 activity, increased its nuclear translocation, thereby, enhanced the expression of its downstream molecules such as NQO1 and HO-1. When Nrf2 was silenced by siRNA, ISOI could not rescue the decrease of TJ proteins induced by LPS any more. In addition, ISOI pre-treatment reduced the elevation of VCAM-1, IL-1β and TNF-α at either protein or mRNA levels, and abrogated the increased adhesion of the monocyte JAWS II cells onto bEnd.3 cells stimulated with LPS. Taken together, these results indicated that ISOI could protect the integrity of the BBB under inflammatory conditions, which was probably mediated through activating the Nrf2 antioxidant pathway.

Endothelial pro inflammatory activation is a key event in the development of atherosclerosis. In order to study modulation of endothelial activation, quantification of the same in vitro is necessary. At functional level endothelial activation is quantified using monocyte adhesion assay. This involves addition of fluorescently labelled monocytes on top of cultured endothelial cells and quantifying the number of monocytes adhered. Currently this is done using microscopy. He we present a novel flow cytometry based monocyte adhesion assay with clear advantages over previously described methods.

Low shear stress serves an important role in the initiation and progression of atherosclerotic lesions, with an impact on progression, but its detailed mechanisms are .not yet fully known. The present study aimed to investigate endothelial cell (EC) apoptosis, as well as monocyte adhesion induced by low shear stress and the potential underlying mechanisms. The expression of platelet endothelial cell adhesion molecule‑1 (PECAM‑1) was demonstrated to be enhanced in human umbilical vascular ECs with a trend that was associated with time when stimulated by low shear stress compared with unstimulated cells. EC apoptosis was increased under low shear stress compared with unstimulated cells, and knockdown of PECAM‑1 inhibited this process. Furthermore, downregulation of PECAM‑1 reduced monocyte adhesion induced by low shear stress compared with that in the negative control cells. Mechanistically, PECAM‑1 small interfering RNA transfection increased Akt and forkhead box O1 phosphorylation under low shear stress conditions compared with that in the negative control cells. Collectively, the findings of the present study revealed that low shear stress induced EC apoptosis and monocyte adhesion by upregulating PECAM‑1 expression, which suggested that PECAM‑1 may be a potential therapeutic target for atherosclerosis.

Erythorbyl laurate (EL) can be produced via lipase-catalyzed esterification between erythorbic acid and lauric acid. In this study, we evaluate the anti-inflammatory effect of EL in the early stage of atherosclerosis. EL suppressed tumor necrosis factor (TNF)-α-induced monocyte adhesion to vascular endothelial cells and expression of vascular cell adhesion molecule (VCAM)-1 in human umbilical vein endothelial cells (HUVECs). Additionally, EL suppressed TNF-α-induced p65/IκB kinase (IKK)/IκB phosphorylation in HUVECs. Western blot analysis of cytosolic and nuclear cell fractions and immunofluorescence showed that EL suppressed TNF-α-induced translocation of p65 from the cytoplasm to the nucleus. EL also inhibited phosphorylation of extracellular-signal-regulated kinase (ERK) 1/2, p38, and c-Jun N-terminal kinases (JNK) 1/2 in HUVECs. EL suppressed TNF-α-induced phosphorylation of Akt, IRAK1, and TAK1 in HUVECs. Quantitative RT-PCR analysis showed that EL significantly suppressed TNF-α-induced interleukin (IL)1B, IL6, TNFA, and CCL2 mRNA expression in HUVECs. Additionally, oral administration of EL suppressed TNF-α-induced IL6 and TNFA expression in the mouse aorta. EL could represent a promising functional nutrient that can be ingested for the prevention of vascular inflammation via decreased monocyte infiltration to the vascular endothelium and suppression of inflammatory nuclear factor (NF)-κB and mitogen-activated protein kinases (MAPKs) signaling pathways.

Patogeneze aterosklerotickeho plaku je dlouhodobý a velmi komplexni proces, jenž postihuje nejprve silně hemodynamicky namahane oblasti cev. Ackoli se klinicke komplikace projevuji větsinou až od středniho věku, prvni znamky tvorby plaku se objevuji již od velmi raneho dětstvi [1]. Přestože je endotel tvořen pouze jednou vrstvou buněk, hraje velice důležitou roli v rozvoji aterosklerozy. Endotel produkuje celou řadu bioaktivnich latek ovlivňujicich cevni tonus, buněcnou adhezi, zanět v cevni stěně, rezistenci vůci tvorbě trombu, ale i proliferaci buněk hladke svaloviny cev. Na uplnem pocatku tvorby aterosklerotickeho plaku dochazi k adhezi monocytů k endotelu a nasledne migraci do hlubsich vrstev cevni stěny. Později monocyty v cevni stěně diferencuji v makrofagy a při trvani patologických podminek dochazi k prohloubeni lokalniho zanětu a jejich postupne přeměně z tkaňových makrofagů v pěnove buňky.

The vascular endothelium is a continuous monolayer of endothelial cells that are in direct contact with the blood and its dysfunction is the starting process in the development of many pathological inflammatory disorders, such as atherosclerosis, which can result in death. The expression of adhesion molecules such as vascular cell adhesion molecule 1 (VCAM1) and intercellular adhesion molecule 1 (ICAM1) is a key stage in modulating vascular inflammation, where the adhesion of monocytes and their transmigration into the intima starting a cascade of inflammatory reactions. Looking for natural compounds with inhibitory activity of VCAM1 and ICAM1, we isolated drimenol, isodrimeninol and polygodial as the main secondary metabolites from barks of Drimys winteri (Dw) and evaluated their effects in the adhesion response of monocytes cells (THP1) to a monolayer of human umbilical vein endothelial cells (HUVEC) in coculture assays. The results showed that the molecules and total extract Dw decrease the adhesion of THP1 to HUVECs, at 10 μg/mL. The adhesion activity is explained due to the inhibition of VCAM1 and ICAM1 evidenced by qRT-PCR and Western-blot assays. In conclusion, drimane sesquiterpenoids could be used as a molecular scaffold in the development of drugs for inflammatory vascular diseases.

Calciprotein particles (CPPs), which increasingly arise in the circulation during the disorders of mineral homeostasis, represent a double-edged sword protecting the human organism from extraskeletal calcification but potentially causing endothelial dysfunction. Existing models, however, failed to demonstrate the detrimental action of CPPs on endothelial cells (ECs) under flow. Here, we applied a flow culture system, where human arterial ECs were co-incubated with CPPs for 4 h, and a normolipidemic and normotensive rat model (10 daily intravenous injections of CPPs) to simulate the scenario occurring in vivo in the absence of confounding cardiovascular risk factors. Pathogenic effects of CPPs were investigated by RT-qPCR and Western blotting profiling of the endothelial lysate. CPPs were internalised within 1 h of circulation, inducing adhesion of peripheral blood mononuclear cells to ECs. Molecular profiling revealed that CPPs stimulated the expression of pro-inflammatory cell adhesion molecules VCAM1 and ICAM1 and upregulated transcription factors of endothelial-to-mesenchymal transition (Snail, Slug and Twist1). Furthermore, exposure to CPPs reduced the production of atheroprotective transcription factors KLF2 and KLF4 and led to YAP1 hypophosphorylation, potentially disturbing the mechanisms responsible for the proper endothelial mechanotransduction. Taken together, our results suggest the ability of CPPs to initiate endothelial dysfunction at physiological flow conditions.

Apabetalone (RVX-208, 200 mg/d) given orally to patients with diabetes mellitus (DM) and CVD leads to a 57% relative risk reduction in major adverse cardiovascular events (MACE). Potential actions of RVX-208, an inhibitor (BETi) of bromodomain extra-terminal (BET) proteins that are epigenetic readers of acetylated lysine residues within histones, in lowering MACE is explored by testing its effect on genes mediating monocyte adhesion to endothelial cells in response to high glucose (HG) and the dietary metabolite trimethyl-amine oxide (TMAO). Cultured THP-1 monocytes, HUVEC endothelial cells and primary human hepatocytes (PHH) were exposed to varying concentrations of glucose and TMAO. Results showed that HG (25.6 mM) induced Very Late Antigen-4 (VLA-4) mRNA, a gene mediating THP-1 adhesion by 1.3-fold and RVX-208 suppressed it >50%. Similarly, BETi blocked TMAO induction of VLA-4 mRNA by >50% in THP-1. In HUVECs RVX-208 abrogated HG induction of E-selectin and MYD88 mRNA by 2- and 1.3-fold, respectively and lowered TMAO induction of these mRNAs by >50%. Microbiome processing of dietary phospholipids followed by hepatic flavin mono-oxygenase-3 (FMO3) metabolism yields TMAO. In PHH exposed for 24 hrs to RVX-208, FMO3 mRNA was lower by 40% but it also suppressed a transcriptional regulator of FMO3, farnesoid X receptor (FXR). BETi suppressed both FXR mRNA and protein within 6 hrs by >80% suggesting a direct effect of BETi on the gene encoding FXR. Furthermore, ChiP data showed that BRD4, a BET protein, dissociated immediately from FXR gene upon exposure to RVX-208. Since BRD4 guides a complex containing RNA pol II along actively transcribed genes containing histones that are highly acetylated, the dissociation of BRD4 from FXR DNA would halt transcription of this gene. In summary, Apabetalone inhibits HG and TMAO enhanced adhesion of THP-1 to HUVECs a process that mimics a step in the pathogenesis of CVD. RVX-208 suppresses genes underlying cellular adhesion; VLA-4 in THP-1 and both E-selectin plus MYD88 in HUVECs. BETi blocks not only activity of TMAO but also its production by inhibiting FXR expression, a regulator of FMO3 gene transcription. The rapid actions of BETi in dissociating BRD4 from FXR DNA suggests a direct effect of RVX-208 on transcription of this gene.

A series of pyridine-linked indanone derivatives were designed and synthesized to discover new small molecules for the treatment of inflammatory bowel disease (IBD). Compounds 5b and 5d exhibited strongest inhibitory activity against TNF-α-induced monocyte adhesion to colon epithelial cells (an in vitro model of colitis). In TNBS (2,4,6-trinitrobenzenesulfonic acid)-induced rat colitis model, oral administration of the compounds 5b and 5d ameliorated colitis with significant recovery in altered expressions of E-cadherin, TNF-α and IL-1β expressions, indicating 5b and 5d as potential agents for therapeutics development against IBD.

Caffeic acid phenethyl ester (CAPE), one of the major polyphenols, exhibits anti-oxidative, anti-bacterial, and anti-cancer properties. Atherosclerosis is a chronic inflammatory disease, the progression of which is closely related to the accumulated adhesion of inflammatory monocytes/macrophages to the endothelium. We herein determined whether CAPE and its derivatives suppressed THP-1 cell adhesion to human umbilical vein endothelial cells (HUVEC). Of the four polyphenols tested, CAPE significantly suppressed the 12-O-tetradecanoylphorbol 13-acetate (TPA)-elicited expression of cluster for differentiation (CD) 11b, 14, and 36, and this was accompanied by the inhibition of THP-1 cell adhesion to HUVEC. CAPE also suppressed the activation of TPA-elicited nuclear factor-κB (NF-κB) and accumulation of NADPH oxidase 2 (NOX2)-derived reactive oxygen species (ROS), but did not affect extracellular signal-regulated kinase (ERK) phosphorylation. Taken together, these results demonstrated that CAPE suppressed THP-1 cell adhesion to HUVEC through, at least in part, the NF-κB, NOX2, and ROS-derived signaling axis.

Cardioprotective effects of dietary anthocyanins are partly attributed to their ability to maintain endothelial function. However, the underlying cellular and molecular mechanisms of action are not fully understood. This study aimed to evaluate the effect of anthocyanins and their gut metabolites, at physiologically-relevant conditions, on endothelial cell (EC) function and decipher the underlying molecular mechanisms of action using integrated omics approaches. Primary EC were treated with a mixture of 0.1 mu M cyanidin-3-arabinoside, 0.1 mu M cyanidin-3-galactoside, 0.1 mu M cyanidin-3-glucoside, 0.1 mu M delphinidin-3-glucoside, 0.1 mu M peonidin-3-glucoside and 0.5 mu M 4-hydroxybenzaldehyde for 3 h or a mixture of gut metabolites: 0.2 mu M protocatechuic, 2 mu M vanillic, 1 mu M ferulic and 2 mu M hippuric acids for 18 h. Also, successive exposure of EC to both mixtures was performed to mimic anthocyanin pharmacokinetics following their intake. Inflammatory stress was induced using TNF alpha and monocytes added to assess adhesion and transmigration. Effects of these mixtures on gene, miRNA expression and their potential interaction with cell signalling were investigated. Anthocyanins and their gut metabolites significantly reduced monocyte adhesion and transendothelial migration. Gene expression analysis, using macroarrays, showed that tested compounds modulated the expression of genes involved in cell-cell adhesion, cytoskeleton organisation or focal adhesion. Bioinformatics analyses of gene expression data identified potential transcription factors involved in the observed nutrigenomic effects and signalling proteins regulating their activity. Molecular docking revealed cell signalling proteins to which these bioactives may bind to and potentially affect their activity and the activation of downstream signalling, effects that were in agreement with the results of Western blot analyses. Microarray analysis showed that anthocyanins and their gut metabolites affected miRNA expression in EC, especially those involved in regulation of EC permeability, contributing to the observed changes in EC function. Integration of these results revealed endothelial-protective properties of anthocyanins and their gut metabolites and deciphered new underlying multi-target and multi-layered mode of action.

Tobacco smoking and hemodynamic forces are key stimuli in the development of endothelial dysfunction and atherosclerosis. High laminar flow has an atheroprotective effect on the endothelium and leads to a reduced response of endothelial cells to cardiovascular risk factors compared to regions with disturbed or low laminar flow. We hypothesize that the atheroprotective effect of high laminar flow could delay the development of endothelial dysfunction caused by cigarette smoking. Primary human endothelial cells were stimulated with increasing dosages of aqueous cigarette smoke extract (CSEaq). CSEaq reduced cell viability in a dose-dependent manner. The main mediator of cellular adaption to oxidative stress, nuclear factor erythroid 2-related factor 2 (NRF2) and its target genes heme oxygenase (decycling) 1 (HMOX1) or NAD(P)H quinone dehydrogenase 1 (NQO1) were strongly increased by CSEaq in a dose-dependent manner. High laminar flow induced elongation of endothelial cells in the direction of flow, activated the AKT/eNOS pathway, increased eNOS expression, phosphorylation and NO release. These increases were inhibited by CSEaq. Pro-inflammatory adhesion molecules intercellular adhesion molecule-1 (ICAM1), vascular cell adhesion molecule-1 (VCAM1), selectin E (SELE) and chemokine (C-C motif) ligand 2 (CCL2/MCP-1) were increased by CSEaq. Low laminar flow induced VCAM1 and SELE compared to high laminar flow. High laminar flow improved endothelial wound healing. This protective effect was inhibited by CSEaq in a dose-dependent manner through the AKT/eNOS pathway. Low as well as high laminar flow decreased adhesion of monocytes to endothelial cells. Whereas, monocyte adhesion was increased by CSEaq under low laminar flow, this was not evident under high laminar flow. This study shows the activation of major atherosclerotic key parameters by CSEaq. Within this process, high laminar flow is likely to reduce the harmful effects of CSEaq to a certain degree. The identified molecular mechanisms might be useful for development of alternative therapy concepts., Highlights • CSEaq induces anti-oxidative enzymes and adhesion molecules in endothelial cells. • CSEaq increases monocyte adhesion to endothelial cells under low laminar flow. • Protective effects of high laminar flow on wound healing are inhibited by CSEaq. • Protective activation of PI3K/AKT/eNOS pathway by high laminar flow is inhibited by CSEaq.

Vascular inflammation and oxidative stress are the major causes of endothelial dysfunction leading to cardiovascular disease. Previously, we have reported the anti-inflammatory activity of zein hydrolysate and its-derived peptides. However, the underlying mechanisms have not been understood. In this study, we report that zein hydrolysate and its derived peptides can inhibit the tumor necrosis factor-α (TNF-α)-induced expression of intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), the adhesion of U937 cells to EA.hy926 cells and superoxide production in EA.hy926 cells. Zein hydrolysate and its peptides also suppressed TNF-α-induced down-regulation of TNF receptor 1 (TNFR1) and phosphorylation of p65 involved in modulation of the NF-κB pathway. Our study suggests that zein hydrolysate and its derived peptides exhibited anti-inflammatory activity via preventing TNF-α induced monocyte adhesion to endothelial cells and NF-κB activation.

Background Plantago asiatica has been traditionally used for traditional medicine around East Asia. Plantamajoside (PM), which is isolated from this plant, is known for biological properties including anti-inflammation and antioxidant activity. To demonstrate the biological activity of PM against endothelial dysfunction induced by advanced glycation end-products (AGEs), a cellular inflammatory mechanism system was evaluated in human umbilical vein endothelial cells (HUVECs). Methods We obtained PM through previous research in our laboratory. We formed the AGEs from bovine serum albumin with glyceraldehyde in the dark for seven days. To confirm the modulation of the inflammatory mechanism in endothelial dysfunction, we quantified the various pro-inflammatory cytokines and endothelial dysfunction-related proteins in the HUVECs with Western blotting and with real-time and quantitative real-time polymerase chain reactions. Results Co-treatment with PM and AGEs significantly suppressed inflammatory cytokines and adhesion molecule expression. Moreover, the PM treatment for down-regulated inflammatory signals and blocked monocyte adhesion on the HUVECs. Conclusions Theses results demonstrated that PM, as a potential natural compound, protects AGE-induced endothelial cells against inflammatory cellular dysfunction. Electronic supplementary material The online version of this article (doi:10.1186/s12906-017-1570-1) contains supplementary material, which is available to authorized users.

Curcumin is a phenolic compound that exhibits beneficial properties for cardiometabolic health. We previously showed that curcumin reduced the infiltration of immune cells into the vascular wall and prevented atherosclerosis development in mice. This study aimed to investigate the effect of curcumin on monocyte adhesion and transendothelial migration (TEM) and to decipher the underlying mechanisms of these actions. Human umbilical vein endothelial cells (HUVECs) were exposed to curcumin (0.5-1μM) for 3h prior to their activation by Tumor Necrosis Factor alpha (TNF-α). Endothelial permeability, monocyte adhesion and transendothelial migration assays were conducted under static condition and shear stress that mimics blood flow. We further investigated the impact of curcumin on signaling pathways and on the expression of genes using macroarrays. Pre-exposure of endothelial cells to curcumin reduced monocyte adhesion and their transendothelial migration in both static and shear stress conditions. Curcumin also prevented changes in both endothelial permeability and the area of HUVECs when induced by TNF-α. We showed that curcumin modulated the expression of 15 genes involved in the control of cytoskeleton and endothelial junction dynamic. Finally, we showed that curcumin inhibited NF-κB signaling likely through an antagonist interplay with several kinases as suggested by molecular docking analysis. Our findings demonstrate the ability of curcumin to reduce monocyte TEM through a multimodal regulation of the endothelial cell dynamics with a potential benefit on the vascular endothelial function barrier.

15-Deoxy-delta12,14-prostaglandin J2 (15d-PGJ2) is an electrophilic lipid mediator derived from PGD2 with potent anti-inflammatory effects. These are likely to be due to the covalent modification of cellular proteins, via a reactive α,β-unsaturated carbonyl group in its cyclopentenone ring. This study was carried out to identify novel cellular target(s) for covalent modification by 15d-PGJ2 and to investigate the anti-inflammatory effects of the prostaglandin on endothelial cells. The data presented here show that 15d-PGJ2 modifies and inhibits components of the proteasome and consequently inhibits the activation of the NF-kB pathway in response to TNF-a. This, in turn, inhibits the adhesion and migration of monocytes toward activated endothelial cells, by reducing the expression of adhesion molecules and chemokines in the endothelial cell. The effects are consistent with the covalent modification of 13 proteins in the 19S particle of the proteasome identified by mass spectrometry and the suppression of proteasome function, and were similar to the effects seen with a known proteasome inhibitor (MG132). The ubiquitin-proteasome system has been implicated in the regulation of several inflammatory processes and the observation that 15d-PGJ2 profoundly affects the proteasome functions in human endothelial cell suggests that 15d-PGJ2 may regulate the progression of inflammatory disorders such as atherosclerosis.

Oxidized low-density lipoprotein (oxLDL) accumulates early in atherosclerotic lesions and plays an important role in the progressive formation of atherosclerotic plaques. Endothelial derived microparticles (EMPs) form a heterogeneous population of

The intercellular adhesion molecule-1 (ICAM-1) expression is frequently correlated with the lung inflammation. A bioactive sphingolipid metabolite, sphingosine-1-phosphate (S1P), was involved in inflammation through the adhesion molecules induction, and then caused lung injury. However, the transduction mechanisms of the S1P stimulation to induce ICAM-1 expression in human pulmonary alveolar epithelial cells (HPAEpiCs) remain unclear. Here, we demonstrated that exposure of HPAEpiCs to S1P significantly induces ICAM-1 expression leading to increase monocyte adhesion on the surface of HPAEpiCs. These phenomena were effectively attenuated by pretreatments with series of inhibitors such as Rottlerin (PKCdelta), PF431396 (PYK2), diphenyleneiodonium chloride (DPI), apocynin (NADPH oxidase), Edaravone (ROS), and Bay11-7082 (NF-kappaB). Consistently, knockdown with siRNA transfection of PKCdelta, PYK2, p47phox, and p65 exhibited the same results. Pretreatment with both Gq-coupled receptor antagonist (GPA2A) and Gi/o-coupled receptor antagonist (GPA2) also blocked S1P-induced ICAM-1 protein and mRNA expression. We observed that S1P induced PYK2 activation via a Gq-coupled receptor/PKCdelta-dependent pathway. In addition, S1P induced NADPH oxidase activation and intracellular ROS generation, which were also reduced by Rottlerin or PF431396. We demonstrated that S1P induced NF-kappaB p65 phosphorylation and translocation from the cytosol to the nucleus in HPAEpiCs, which was inhibited by Rottlerin, PF431396, APO, DPI, or Edaravone. In the in vitro study, we established that S1P induced monocyte adhesion via an ICAM-1-dependent pathway. In the in vivo study, we found that S1P induced ICAM-1 protein and mRNA levels in the lung fractions, pulmonary hematoma, and leukocyte (mainly eosinophils and neutrophils) count in bronchoalveolar lavage (BAL) fluid in mice via a PKCdelta/PYK2/NADPH oxidase/ROS/NF-kappaB signaling pathway. We concluded that S1P may induce lung inflammation via ICAM-1 induction associated with leukocyte recruitment.

Adhesion and proliferation of vascular endothelial cells are important parameters in the endothelialization of biomedical devices for vascular applications. Endothelialization is a complex process affected by endothelial cells and their interaction with the extracellular microenvironment. Although numerous approaches are taken to study the influence of the external environment, a systematic investigation of the impact of an engineered microenvironment on endothelial cell processes is needed. This study aims to investigate the influence of topography, initial cell seeding density, and collagen coating on human umbilical vein endothelial cells (HUVECs). Utilizing the MultiARChitecture (MARC) chamber, the effects of various topographies on HUVECs are identified, and those with more prominent effects were further evaluated individually using the MARC plate. Endothelial cell marker expression and monocyte adhesion assay are examined on the HUVEC monolayer. HUVECs on 1.8 μm convex and concave microlens topographies demonstrate the lowest cell adhesion and proliferation, regardless of initial cell seeding density and collagen I coating, and the HUVEC monolayer on the microlens shows the lowest monocyte adhesion. This property of lens topographies would potentially be a useful parameter in designing vascular biomedical devices. The MARC chamber and MARC plate show a great potential for faster and easy pattern identification for various cellular processes.

Transmigration of leukocytes across the endothelial barrier is a tightly controlled process involving multiple steps, including rolling adhesion, firm adhesion, and then penetration of leukocytes through the endothelial monolayer. While the key molecular signals have been described in great detail, we are only just beginning to unveil the mechanical forces involved in this process. Here, using a microfabricated system that reports traction forces generated by cells, we describe forces generated by endothelial cells during monocyte firm adhesion and transmigration. Average traction force across the endothelial monolayer increased dramatically when monocytes firmly adhered and transmigrated. Interestingly, the endothelial cell that was in direct contact with the monocyte exhibited much larger traction forces relative to its neighbors, and the direction of these traction forces aligned centripetally with respect to the monocyte. The increase in traction force occurred in the local subcellular zone of monocyte adhesion, and dissipated rapidly with distance. To begin to characterize the basis for this mechanical effect, we show that beads coated with anti-ICAM-1 or VCAM-1 antibodies bound to monolayers could reproduce this effect. Taken together, this study provides a new approach to examining the role of cellular mechanics in regulating leukocyte transmigration through the endothelium.

Woven poly(ethylene terephthalate) (PET) is widely used in implantable medical devices. Upon implantation, fibrinogen interacts with the PET and changes conformation, such that the fibrinogen P2 epitope may become exposed. This allows inflammatory cells to interact with the material. In this study we have coated PET with heparin and show that this decreases PET hydrophobicity and the presence of the fibrinogen P2 epitope on the material surface. In addition, we show that heparin-induced reduction of PET hydrophobicity correlates with decreased exposure of the fibrinogen P2 epitope and reduced adhesion of monocytes. Reduction of PET hydrophobicity was furthermore associated with reduced PMN elastase production and decreased interaction between PET and embryonic chicken tissue. We conclude that the heparin coating-induced decrease in PET hydrophobicity is associated with decreased interaction between PET and inflammatory cells. Independent of this interaction, the hydrophobic nature of the heparin coating is related to tissue interaction as demonstrated by a reduction in adhesion, growth and spreading of tissue on PET. The combination of these properties makes heparin coating a candidate for improving biocompatibility of PET. (C) 2008 Elsevier B.V. All rights reserved.

2-Methoxyestradiol (2-ME) reduces atherosclerotic lesion formation. However, the underlying mechanisms remain largely unknown. In this work, we investigated the effect of 2-ME on monocyte adhesion to vascular endothelial cells. Lipopolysaccharides (LPS) greatly increased the attachment of monocyte onto cultured human umbilical vascular endothelial cells (HUVECs), which was inhibited by 2-ME in a dose- and time-dependent manner, or by the vascular cell adhesion protein-1 (VCAM-1) neutralizing antibody, suggesting that a functional releationship between 2-ME and VCAM-1 may exist. In accordance with this, treatment with 2-ME (10(-)(7)-10(-)(5) M) for 6-48 h downregulated VCAM-1 protein expression. Meanwhile, the nuclear factor κB (NF-κB) p65 subunit activity and its nuclear translocation was inhibited by 2-ME in HUVECs. The PI3K inhibitor wortmannin or the specific Akt siRNA both inhibited the effects of 2-ME, suggesting that 2-ME inhibited p65 activity via PI3K/Akt signaling. In conclusion, 2-ME inhibits VCAM-1 expression and thus prevents monocyte adhesion to vascular endothelial cells via regulation of PI3K/Akt and NF-κB signaling. These findings will be helpful for better understanding the mechanisms through which 2-ME improves endothelial function.

Thiazolidinediones (TZDs), potent peroxisome proliferator-activated receptor γ ligands, have been shown to improve endothelial function in vascular diseases. We investigated the effects of pioglitazone, a TZD, on monocyte–endothelial interaction under flow and found that pretreatment (20 μmol/l, 48 h) significantly reduced U937 adhesion to human umbilical vein endothelial cells. Integrin expression was not altered, however, the activation of RhoA GTPase was significantly reduced after treatment. Further, pioglitazone treatment significantly reduced phosphorylation of focal adhesion kinase (FAK) at 925Y, but not at 397Y, suggesting a specific role in FAK-dependent signaling. These results indicate a novel anti-inflammatory role for this compound.

Adhesion of leukocytes to endothelial cells plays an important role in neuroinflammation. Therefore, suppression of the expression of adhesion molecules in brain endothelial cells may inhibit neuroinflammation. Chrysin (5,7-dihydroxyflavone) is a flavonoid component of propolis, blue passion flowers, and fruits. In the present study, we examined the effects of chrysin on lipopolysaccharide (LPS)-induced expression of vascular cell adhesion molecule-1 (VCAM-1) in mouse cerebral vascular endothelial (bEnd.3) cells. In bEnd.3 cells, LPS increased mRNA expression of VCAM-1 in a time-dependent manner, and chrysin significantly decreased LPS-induced mRNA expression of VCAM-1. Chrysin also reduced VCAM-1 protein expression in a concentration-dependent manner. Furthermore, chrysin blocked adhesion of monocytes to bEnd.3 cells exposed to LPS. Nuclear factor-κB (NF-κB), p38 mitogen-activated protein kinase (MAPK), and c-Jun N-terminal kinase, which are all activated by LPS, were significantly inhibited by chrysin. These results indicate that chrysin inhibits the expression of VCAM-1 in brain endothelial cells by inhibiting NF-κB translocation and MAPK signaling, resulting in the attenuation of leukocyte adhesion to endothelial cells. The anti-inflammatory effects of chrysin suggest a possible therapeutic application of this agent to neurodegenerative diseases, such as multiple sclerosis, septic encephalopathy, and allergic encephalomyelitis.