Alkamides from the fruits of Piper longum and Piper nigrum displaying potent cell adhesion inhibition

Eight alkamides 1-8 were isolated by bioassay-guided isolation of EtOH extracts of the fruits of Piper longum and Piper nigum (Piperaceae). Their structures were elucidated by spectroscopic analysis ((1)H, (13)C NMR, and ESI-MS) as follows: guineensine (1), retrofracamide C (2), (2E,4Z,8E)-N-[9-(3,4-methylenedioxyphenyl)-2,4,8-nonatrienoyl]piperidine (3), pipernonaline (4), piperrolein B (5), piperchabamide D (6), pellitorin (7), and dehydropipernonaline (8). Their compounds 3-5, 7, and 8 inhibited potently the direct binding between sICAM-1 and LFA-1 of THP-1 cells in a dose-dependent manner, with IC(50) values of 10.7, 8.8, 13.4, 13.5, and 6.0 microg/mL, respectively.     

Simvastatin modulates TNFalpha-induced adhesion molecules expression in human endothelial cells

Adhesion and transendothelial migration of leukocytes into the vascular wall is a crucial step in atherogenesis. Expression of cell adhesion molecules by endothelial cells plays a leading role in this process. We investigated the effect of simvastatin, an inhibitor of HMG-CoA reductase administered to reduce plasma levels of LDL-cholesterol, on the expression of vascular cell adhesion molecule-1 (VCAM-1) and intracellular cell adhesion molecule-1 (ICAM-1) by human umbilical vein endothelial cells (HUVEC) stimulated with tumor necrosis factor alpha (TNFalpha). We found the expression to be significantly inhibited by the drug in a time and concentration-dependent manner and to a greater extent in the case of VCAM-1 as compared with ICAM-1. In TNFalpha-stimulated HUVEC, simvastatin decreased VCAM-1 and ICAM-1 mRNA levels, inhibited TNFalpha-induced activation of nuclear factor kappaB (NF-kappaB) and enhanced expression of peroxisome proliferator-activated receptor alpha (PPARalpha). These effects were associated with reduction of adherence of monocytes and lymphocytes to HUVEC. The present findings suggest that the benefits of statins in vascular disease may include the inhibition of expression of VCAM-1 and ICAM-1 through effects on NF-kappaB.     

Methyl mercury triggers endothelial leukocyte adhesion and increases expression of cell adhesion molecules and chemokines

Cardiovascular disease is the leading cause of morbidity, mortality, and health care costs in the USA, and around the world. Among the various risk factors of cardiovascular disease, environmental and dietary exposures to methyl mercury, a highly toxic metal traditionally labeled as a neurotoxin, have been epidemiologically linked to human cardiovascular disease development. However, its role in development and promotion of atherosclerosis, an initial step in more immediately life-threatening cardiovascular diseases, remains unclear. This study was conducted to examine the role that methyl mercury plays in the adhesion of monocytes to human microvascular endothelial cells (HMEC-1), and the underlying mechanisms. Methyl mercury treatment significantly induced the adhesion of monocyte to HMEC-1 endothelial cells, a critical step in atherosclerosis, while also upregulating the expression of proinflammatory cytokines interleukin-6, interleukin-8. Further, methyl mercury treatment also upregulated the chemotactic cytokine monocyte chemoattractant protein-1 and intercellular adhesion molecule-1. These molecules are imperative for the firm adhesion of leukocytes to endothelial cells. Additionally, our results further demonstrated that methyl mercury stimulated a significant increase in NF-κB activation. These findings suggest that NF-κB signaling pathway activation by methyl mercury is an important factor in the binding of monocytes to endothelial cells. Finally, by using flow cytometric analysis, methyl mercury treatment caused a significant increase in necrotic cell death only at higher concentrations without initiating apoptosis. This study provides new insights into the molecular actions of methyl mercury that can lead to endothelial dysfunction, inflammation, and subsequent atherosclerotic development.     

Molecular docking analysis of vascular endothelial growth factor receptor with bioactive molecules from Piper longum as potential anti-cancer agents

It is known that vascular endothelial growth factor receptor (VGFR) is linked with cancer. Therefore, it is of interest to document the molecular binding features of bioactive molecules from Piper longum as potential anti-cancer agents with VGFR2 for further consideration. Thus, we document the binding features of four compounds (sesamin, fargesin, longamide and piperlonguminine) with VGFR2 for further consideration in drug discovery.     

Effect of high-density lipoproteins on the expression of adhesion molecules in endothelial cells

There are several potential mechanisms by which HDLs protect against atherosclerosis. One relates to the ability of HDLs to promote the efflux of cholesterol from macrophages. Another is the ability of HDLs to inhibit one of the earliest events in the development of atherosclerosis, namely the expression of vascular cell adhesion molecules in activated endothelial cells. This property has been reported in vitro in studies with both native and reconstituted HDLs. The inhibitory activity of reconstituted HDLs is influenced by the phospholipid composition of the particles. An inhibition of endothelial cell adhesion molecule expression has also been observed in some (but not all) studies conducted in vivo in mice and pigs. The mechanism of this potentially anti-atherogenic effect of HDLs remains uncertain, as does its contribution to the cardioprotective effects of HDLs in vivo.     

Messages from forgotten friends: classic cell adhesion molecules inhibit regeneration too

A necessary step toward complete functional recovery after spinal cord injury is the regeneration of axons. Axon regrowth after injury is prevented by a myriad of intrinsic and extrinsic factors. In this issue of The EMBO Journal, Huang et al ( 2016 ) demonstrate that the cell adhesion molecule NB‐3 (CNTN6) functions as a major brake on axon regrowth when it is activated by NB‐3 from scar‐forming cells at the injury site. Disruption of this NB‐3 trans‐cellular signaling led to impressive axon regrowth after spinal cord transection.     

N—乙酰氨基葡萄糖转移酶—V过表达对人肝癌细胞迁移及粘附分子表达的影响

The purpose of this paper is to study the effect of N-acetylglucosaminyltransferase V (GnT-V) overexpression on the migration of 7721 cells and its mechanism. The abilities of migration of both 7721 cells transfected with GnT-V cDNA and 7721 cells transfected with pcDNA3 was detected, the expressions of integrin and E-cadherin which are important adhesion molecules on surface membrane and closely related to the abilities of invasion and metastasis. Cell migration abilities were measured by the agarose drop explant method. Flow cytometric analysis (FACS) was applied to determine the relative amounts of integrin alpha 5 and beta 1 subunits on the cell surface while RTPCR was carried out to determine the expression of their mRNA. The expression of E-cadherin was examined by the immunocytochemical ABC method. Western blot analysis was carried out to examine the expression of beta-catenin. GnT-V overexpression enhanced evidently the migration ability of 7721 cells and increased the amount of integrin alpha 5 subunit to 2.9 times of that of control while the amount of beta 1 subunits was not significantly changed. Besides, the expressions of E-cadherin and beta-catenin were enhanced at different levels in GnT-V/7721 cells compared with mocked. The results suggested that the overexpression of GnT-V related to the production of N-linked sugar chains could promote the expressions of integrin, E-cadherin and beta-catenin on 7721 cells so that the migration ability of tumor cells was enhanced.     

13-HPODE and 13-HODE modulate cytokine-induced expression of endothelial cell adhesion molecules differently

Expression of cellular adhesion molecules (CAMs) at endothelial surfaces represents a physiological response to vascular damage and mediates the initiation of inflammation and possibly of atherogenesis. The cytokines TNF alpha and IL-1 are potent inducers of CAMs in endothelial cells. Reactive oxygen species comprising lipid oxidation products have been implicated in the signaling pathways of both TNF alpha and IL-1 and accordingly could modulate atherogenic events. We, therefore, investigated the potential role of the lipoxygenase product, 13-hydroperoxyoctadecadienoic acid (13-HPODE), which has also been identified in oxidized low density lipoproteins on CAM expression in HUVEC. 13-HPODE induced the expression of ICAM-1 in a concentration dependent manner up to 75 microM. Higher concentrations were toxic. Similar effects were observed with H2O2 and phosphatidylcholine hydroperoxide. VCAM-1 and E-selectin were not induced by 13-HPODE. 13-HPODE administered simultaneously with IL-1 or TNF alpha induced ICAM-1 additively, suggesting that hydroperoxides and cytokines act on the same signaling pathways. In contrast, pretreatment of cells with 50 microM 13-HPODE for 1 hour rather inhibited subsequent cytokine-induced ICAM-1 and E-selectin expression. Surprisingly, the reduction product of 13-HPODE, 13-hydroxyoctadecadienoic acid (13-HODE) proved to be an even better inducer of ICAM-1 than 13-HPODE. Pretreatment with 13-HODE did not show any inhibitory effect on ICAM-1 expression. Our data show that lipoxygenase products differentially affect CAM expression. 13-HPODE is stimulatory by itself and can positively or negatively affect cytokine signaling depending on time of exposure. 13-HODE induces CAM expression by itself but does not inhibit cytokine signaling. Thus, the interplay of lipoxygenase products with proinflammatory cytokines can not simply be explained by an oxidant-mediated facilitation of cytokine signaling.     

Oxidized LDL further enhances expression of adhesion molecules in Chlamydophila pneumoniae-infected endothelial cells

Chlamydophila pneumoniae is a common respiratory pathogen that has been shown to be associated with coronary artery disease. Recent studies have shown that one of the possible mechanisms of the atherogenicity of C. pneumoniae is overexpression of cell adhesion molecules (CAMs) in infected endothelial cells. We investigated whether exposure of C. pneumoniae-infected endothelial cells to oxidized LDL (oxLDL) leads to further upregulation of CAMs. Flow cytometry and immunoblot analysis of human aortic endothelial cells (HAECs) was performed for intracellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and E-selectin. ICAM-1 was expressed in 78.7% of C. pneumoniae-infected HAECs. The addition of oxLDL (100 microg/ml) to infected HAECs increased the proportion of ICAM-1-positive cells to 92%. VCAM-1 was only observed in 9.3% of infected HAECs, and the addition of oxLDL had no further effect on the surface expression of VCAM-1. C. pneumoniae also upregulated the surface expression of E-selectin on 52.2% of the cells, and incubation with oxLDL further increased the proportion of positive cells to 63.64%. In conclusion, C. pneumoniae upregulated the expression of the adhesion molecules ICAM-1, VCAM-1, and E-selectin on HAECs. The addition of oxLDL to the infected cells further enhanced the surface expression of ICAM-1 and E-selectin.     

C-reactive protein induced expression of adhesion molecules in cultured cerebral microvascular endothelial cells

Ischemic stroke can trigger an acute phase response resulting in a rise of plasma concentration of C-reactive protein (CRP). Clinical data about the relationship between CRP and prognosis suggest that CRP might be involved in the pathogenesis of cerebral ischemia. In the present work, a significant increase of circulating level of CRP was observed in an vivo rat brain ischemia model of middle cerebral artery occlusion. To determine the possible effects of CRP on brain microvessel endothelium, we performed a dose-dependent experiment in mouse brain microvascular endothelial cells (bEnd.3 cells) with emphasis on its relation to cell adhesions molecules. Incubation with CRP (1-75 mg/L) for 24 h significantly increased Lactate dehydrogenase (LDH) leakage from bEnd.3 cells (P<0.01) in a dose-dependent manner, and induced significant up-regulations of intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) expressions analyzed by Western blotting (P<0.01). In contrast to earlier report, CRP also induced significant increase in ICAM-1 expression in the absence of serum (P<0.01). In conclusion, the present results suggest that CRP may be involved directly in the development of inflammation in response to cerebral ischemia.     

Silymarin inhibits TNF-alpha-induced expression of adhesion molecules in human umbilical vein endothelial cells

Silymarin is known to have an anti-atherosclerotic activity, but the mechanism responsible for it remains unclear. Here, we demonstrate a possible mechanism involved in the anti-atherosclerotic activity of silymarin. Silymarin inhibited THP-1 cell adhesion to human umbilical vein endothelial cells (HUVECs). Silymarin also suppressed the TNF-alpha-induced protein and mRNA expression of adhesion molecules, such as VCAM-1, ICAM-1 and E-selectin, in HUVECs. Moreover, silymarin suppressed the TNF-alpha-induced DNA binding of NF-kappaB/Rel in HUVECs. Taken together, these results demonstrate that silymarin exerts an anti-atherosclerotic activity, at least in part, by inhibiting the expression of adhesion molecules.     

Novel mode of action of iloprost: in vitro down-regulation of endothelial cell adhesion molecules

Iloprost is a stable prostacyclin analog commonly employed in the treatment of peripheral vascular disease and also indicated in the treatment of patients affected by systemic sclerosis (SSc) in the presence of severe Raynaud's phenomenon (RP). Several mechanisms of action of the drug other than vasodilation and antiplatelet effect have been demonstrated that may be involved in the exertion of its clinical efficacy. Aim of the present study was to investigate whether iloprost down-regulated lymphocyte adhesion to endothelium through a modulation of adhesion molecule expression on the surface of endothelial cells. In the presence of iloprost, both lymphocyte adhesion and IL-1 stimulated expression of ICAM-1 and ELAM-1 exhibited a significant reduction, while unstimulated adhesion molecule expression was not significantly affected. Our results confirm that iloprost is able to down-regulate lymphocyte adhesion to endothelial cells and indicate that endothelium itself could be target of iloprost administration. Attenuation of the inflammatory response through modulation of cellular interactions could be suggested as a potential mechanism of action of iloprost, when used in the treatment of pathological conditions characterized by endothelial activation.     

Heterotypic and homotypic cell-cell adhesion molecules in endothelial cells

Sickle red blood cells display an abnormal propensity to adhere to cultured bovine aortic endothelial cells when compared to normal red blood cells. The adherence was potentiated three-fold by endothelial cell derived conditioned medium, enriched in multimers of von Willebrand factor. Such adherence was ablated by 80% by either the synthetic peptide (RGDS) or antibody to GPIIb/IIIa, indicating the presence of RGD peptide recognition domain/receptor in either endothelial cells or sickle cells or both. The adherence was also inhibited by 70% by phosphatidylserine, but not by other phospholipids, indicating the presence of putative receptors for this phospholipid in endothelial cells. The labeling of cultured bovine aortic endothelial cells with monoclonal antibodies revealed the localization of MAB D2 to regions of cell-cell contact. The antigen on endothelial cells which cross-reacts with this antibody has a Mr of 130,000. The addition of such an antibody during the plating of endothelial cells disrupted monolayer formation. It appears that a 130-kDa polypeptide antigen in endothelial cells which is recognized by MAB D2, may be a cell-cell adhesion molecule.     

A multiparameter screening assay to assess the cytokine-induced expression of endothelial cell adhesion molecules

Compounds which inhibit endothelial cell inflammatory responses are believed to be of therapeutic value. The cell adhesion molecules E-selectin, ICAM-1, and VCAM-1 play important roles in inflammatory reactions by mediating leukocyte-endothelial interactions. To identify compounds which inhibit the expression of these adhesion molecules following cytokine stimulation we developed an assay which measures E-selectin, ICAM-1, and VCAM-1 in the same experiment. For this, we have taken advantage of the technology of time-resolved fluorimetry, which allows detection of several parameters in parallel, employing anti-E-selectin antibody labeled with europium, and anti-ICAM-1 and anti-VCAM-1 labeled with samarium and terbium, respectively. These antibodies were used to detect the respective antigens in human endothelial cells stimulated with TNFalpha or IL-1beta. In cross-competition assays these antibodies were found to bind specifically to TNF- or IL-1-stimulated cells. This assay, in which three parameters are measured in the same experiment, proved to be robust with signal to noise ratios of 25-35 for E-Selectin, 4-8 for ICAM-1, and 3-9 for VCAM-1. The assay proved to be reproducible in high-throughput screening. The experience with this assay demonstrates that multiple parameters can be measured in an enzyme-linked immunosorbent assay-type assay on cells by using time-resolved fluorimetry. The possibility of obtaining several parameters from one experiment is feasible under high-throughput screening conditions and is of interest for other experimental setups in which the simultaneous measurement of several parameters is desired.     

Chrysin and its phosphate ester inhibit cell proliferation and induce apoptosis in Hela cells

To improve the biological activities of chrysin (CR), we synthesize Diethyl Chysin-7-yl phosphate (CPE: C(19)H(19)O(7)P) and tetraethyl bis-phosphoric ester of chrysin (CP: C(23)H(28)O(10)P(2)) through a simplified Atheron-Todd reaction. The interactions of the CR and CPE with lysozyme were explored by electrospray ionization mass spectrometry (ESI) and fluorescence spectrometry method. Experimental results indicate that CPE could form the noncovalent compound with lysozyme, while the interaction of the CR with lysozyme was not detected. In addition, whether and how the compounds CPE and CP affect proliferation and apoptosis in human cervical cancer Hela cells were investigated. Moreover, the effects of CPE and CP in Hela cells were compared with that of the nonmodified CR compound. The Hela cells were co-cultured with CR, CP, and CPE as experimental groups, respectively, and corresponding control groups treated without CR, CP, and CPE. The proliferation and apoptosis were detected using MTT assay, HCl denatured-methyl green-pyronin staining, PCNA immunohistochemistry and TUNEL techniques. The cell growth IC(50), relative absorbance (RA), proliferating index (PI), PCNA-IR (immunoreactivity IR) integration value (IV), and apoptosis index (AI) were calculated and their correlation was analyzed in each group. The results show that all CR, CP, and CPE could inhibit proliferation and induce apoptosis in Hela cells. Moreover, the effects of CP and CPE were more potent than that of CR. The CP and CPE were proved to be a kind of stronger apoptosis inducers than nonphosphated CR. There was a negative correlation between proliferation and apoptosis. In conclusion, the CR, CP, and CPE could effectively inhibit growth by down-regulated expression of PCNA, and induce apoptosis in Hela cells. The efficiency of the modified CP and CPE preceded nonmodified CR compounds. The CP and CPE may be a new potential anti-cancer drug for therapy of human cervical carcinoma.