Published online before print March 16, 2006, doi: 10.1161/01.ATV.0000217909.09198.d6
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© 2006 American Heart Association, Inc.
Vascular Biology |
12/15 Lipoxygenase Mediates Monocyte Adhesion to Aortic Endothelium in Apolipoprotein E–Deficient Mice Through Activation of RhoA and NF-
B
From Cardiovascular Research Center, University of Virginia, Charlottesville.
Correspondence to Catherine C. Hedrick, PhD, Cardiovascular Research Center, University of Virginia, PO Box 801394, 415 Lane Rd; MR5 Rm G123, Charlottesville, VA 22908. E-mail cch6n{at}virginia.edu
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Abstract |
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Objectives— 12/15 lipoxygenase (12/15LO) has been implicated as a mediator of inflammation and atherosclerosis. In the current study, we identified mechanisms through which 12/15LO mediates monocyte:endothelial interactions in vivo in apolipoprotein E-deficient mice (apoEKO), a well-characterized mouse model of atherosclerosis.
Methods and Results— In apoEKO mice that are also deficient in 12/15LO (doubleKO), monocyte adhesion to aorta in vivo was reduced by 95% in doubleKO mice compared with apoEKO mice. Inhibition of 12/15LO in apoEKO mice in vivo using CDC (Cinnamyl-3,4-Dihydroxy-a-Cyanocinnamate) prevented monocyte adhesion to aortic endothelium in apoEKO mice. Aortic endothelium of apoEKO mice had significant activation of rhoA compared with doubleKO aortic endothelium. Further, apoEKO aorta displayed significant activation of NF-
B. DoubleKO aorta displayed little nuclear localization of NF-B. Finally, we found significant upregulation of intercellular adhesion molecule-1 (ICAM-1) on apoEKO aortic endothelium compared with doubleKO endothelium. Inhibition of rhoA and PKC
significantly reduced NF-B activation, ICAM-1 induction, and monocyte adhesion to aorta.
Conclusions— We conclude that 12/15LO products activate endothelial rhoA and PKC. Activation of rhoA and PKC cause activation and translocation of NF-B to the nucleus, which, in turn, results in induction of ICAM-1. Induction of ICAM-1 on aortic endothelium stimulates monocyte:endothelial adhesion in vivo in apoEKO mice.
L12/15 lipoxygenase (12/15LO) products activate endothelial rhoA and PKC. Activation of rhoA and PKC causes activation and translocation of NF-B to the nucleus, which, in turn, results in induction of ICAM-1. Induction of ICAM-1 on aortic endothelium stimulates monocyte:endothelial adhesion in vivo in apoEKO mice.
Key Words: lipoxygenase • NF-B • ICAM-1 • endothelium
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Introduction |
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Akey early event in atherosclerosis development is the interaction of monocytes and endothelial cells in the vessel wall.1 Activated monocytes interact with selectins, intercellular adhesion molecule-1 (ICAM-1), and vascular cell adhesion molecule-1 (VCAM-1) on the endothelial cell surface to roll along and firmly adhere to the endothelium.2,3 Monocytes are the primary inflammatory cells localized to human atherosclerotic plaques and play a major role in atherosclerotic plaque progression.4 The apolipoprotein E-deficient mouse (apoEKO) is a well-characterized model of atherosclerosis that develops extensive aortic and coronary atherosclerosis and severe hypercholesterolemia when fed a Western-type diet.5,6 Studies have reported increased P-selectin–mediated and VCAM-1–mediated monocyte rolling along apoE-deficient mouse endothelium,7,8 and have illustrated that VCAM-1 and ICAM-1 are critical for atherosclerosis development in apoEKO mice.9,10
See page 1204
12/15 lipoxygenase (12/15LO) incorporates molecular oxygen in a stereo-specific manner into arachidonic and linoleic acids to generate 12-S- and 15-S-hydroxyeicosatetraenoic acids (12SHETE/15SHETE) and 13-S-hydroxyoctadecadienoic acid (13SHODE), respectively.11,12 Sources of 12/15LO eicosanoids in vascular cells are endothelial cells, smooth muscle cells, monocytes, and platelets.13 Several groups have shown that the human 12/15LO enzyme oxidizes low-density lipoprotein (LDL) in vitro, and that 12/15LO inhibitors decrease the ability of macrophages to oxidize LDL.14–17 12/15LO protein has been localized to aortic atherosclerotic lesions in rabbits and in humans.18,19 We have shown that activated human endothelial cells (ECs) have increased expression of 12/15LO protein that mediates monocyte adhesion.20 We have also shown that exogenous addition of 12SHETE and 15SHETE to EC significantly increased binding of monocytes.20 Importantly, using a catalytic ribozyme to inactivate 12/15LO mRNA in ECs, we reduced 12SHETE production and blocked monocyte adhesion.21 Striking evidence for a role for 12/15LO in atherogenesis came from the studies of Funk et al, who showed that disruption of the 12/15LO gene in apoE-deficient and LDL receptor-deficient mice significantly reduced atherosclerosis development in vivo.22,23 The mechanism of action of 12/15LO in atherosclerosis remains unclear, and probably relates to signaling by several 12/15LO products in the endothelium of the vessel wall and in monocyte/macrophages.
In the current study, we identify how 12/15LO signals in apoE-deficient mice to upregulate monocyte adhesion to aortic endothelium. We found that 12/15LO activates rhoA and NF-B in vivo in apoEKO aorta to cause increased monocyte:EC interactions. Inhibition of 12/15LO activity in vivo blocks monocyte adhesion to apoE-deficient mouse aorta.
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Methods |
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Detailed methods can be found in an online supplement at http://atvb.ahajournals.org.
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Results |
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Decreased ICAM-1 Expression in ApoE-Deficientx12/15LO-Deficient Mice
We have previously reported increased ICAM-1 expression in 12/15LO transgenic mice.24 We first tested whether ICAM-1 was decreased in apoEKOx12/15LO double knockout (doubleKO) mice compared with apoEKO mice. Total RNA was isolated from aortic endothelial cells (MAEC) from apoEKO and doubleKO aorta and quantitative real-time polymerase chain reaction was performed to measure ICAM-1 mRNA expression. MAEC from doubleKO had significantly lower ICAM-1 mRNA expression than apoEKO (P<0.005) (Figure 1). Levels of VCAM-1 and E-selectin mRNA were similar between both groups (data not shown).
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Inhibition of 12/15LO In Vivo Blocks Monocyte Adhesion to ApoE Mouse Aorta
We next directly tested whether monocyte adhesion to aortic endothelium was altered in apoEKO versus doubleKO mice. Aortas from apoEKO and doubleKO mice were used in an ex vivo monocyte adhesion assay. Aortas from apoEKO bound 
5-fold more monocytes than did doubleKO aortas (P<0.001) (Figure 2). To confirm that the increased monocyte adhesion to aorta observed in the apoEKO mice is caused by 12/15LO activity, we used the 12/15LO inhibitor CDC (Cinnamyl-3,4-Dihydroxy-a-Cyanocinnamate). The apoEKO mice were treated in vivo with a single intraperitoneal injection of 8 mg/kg CDC. Ma et al have shown that this dose of CDC reduces urinary 12SHETE concentrations by 60% in 24 hours in rodents.25 After 24 hours, aortas were isolated and used in the monocyte adhesion assay ex vivo. Treatment of apoEKO mice with CDC in vivo caused a dramatic 75% reduction in monocyte adhesion to aorta (Figure 2). Sesame oil-injected mice were used as vehicle controls and showed no reduction in monocyte adhesion (92±10 monocytes bound/field). The CDC-treated apoEKO mice had approximately the same numbers of monocytes adherent to aorta as did the doubleKO mice. To confirm that 12/15LO products were indeed mediating monocyte adhesion, we performed a series of "addback" experiments in which we incubated doubleKO mouse aortas for 4 hours with 12/15LO product eicosanoids before performing a monocyte adhesion assay. We found that addition of 100 nmol 12SHETE to doubleKO aortas significantly increased monocyte adhesion by 3-fold (12±2 monocytes bound/field for doubleKO aorta and 13±2 monocytes bound for ethanol vehicle control versus 39±6 monocytes bound/field for 12SHETE addition to doubleKO aorta (P<0.001)). Addition of 13SHODE to doubleKO aorta resulted in a 2-fold increase in monocyte adhesion with 28±5 monocytes bound/field (P<0.006). Addition of 15SHETE showed only a slight increase (19±2 monocytes/bound); however, this increase did not reach statistical significance. Addition of 12RHETE, which is not a product of the 12/15LO pathway, had no effect on adhesion (12±2 monocytes bound/field). Addition of eicosanoids to apoEKO aorta did not further increase monocyte adhesion, suggesting that the 12/15LO pathway is the primary pathway mediating the increased adhesion observed in apoEKO aorta. These findings are shown in supplemental Figure I (please see http://atvb.ahajournals.org). These data indicate that the majority of monocyte:endothelial interactions in apoEKO mouse aorta in vivo are mediated by 12/15LO.
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NF-B Is Activated in ApoEKO Aortic Endothelium
Activation of NF-B increases endothelial ICAM-1 expression as well as monocyte adhesion to endothelium.26–28 On NF-B activation, the IB kinase complex phosphorylates IB, resulting in its degradation. This unmasks a nuclear localization signal on the p65 subunit resulting in its translocation to the nucleus. In the first set of experiments, we obtained nuclear extracts from apoEKO and doubleKO mouse aortic endothelium. We performed Western immunoblotting to look for expression of the p65 subunit of NF-B in the nucleus. We found that apoEKO endothelium had increased p65 expression in the nucleus compared with doubleKO endothelium, (Figure 3a), indicating translocation of NF-B from the cytosol to the nucleus to mediate inflammatory gene transcription. Interestingly, doubleKO aortic endothelium had almost no p65 expression in the nucleus (Figure 3a), suggesting that NF-B was not activated in doubleKO mouse aortas.
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The Rho family of GTPases can activate NF-B–dependent gene expression in EC.26 RhoA stimulates NF-B through its downstream effector Rho kinase (ROCK).29 Interestingly, we found that both a rho kinase inhibitor (Y27632) and a PKC inhibitor (GO6976) dramatically reduced NF-B activation in apoEKO mouse aortas.
We also confirmed the lack of p65 translocation to the nucleus of doubleKO aortic endothelium using fluorescence microscopy. Using an anti-p65 antibody together with an Alexa 594–conjugated secondary antibody, we found that NF-B is located primarily in the nucleus of apoEKO mouse endothelium, again confirming NF-B activation and translocation (Figure 3b). In contrast, doubleKO endothelium had little expression of nuclear p65, indicating the NF-B was not activated in the doubleKO mice (Figure 3b). Pretreatment of apoEKO MAEC with the rho kinase inhibitor, the PKC inhibitor, or both compounds together dramatically reduced p65 nuclear localization. The percentage of nuclei positive for NF-B p65 was 77±4% for apoEKO, 22±2% for apoEKO+Y27632, 20±1% for apoEKO+Go6976, 18±1% for apoEKO+both inhibitors together; 12±1% for doubleKO, 8±1% for doubleKO+ Y27632, 10±2% for doubleKO+Go6976, and 8±1% for doubleKO+both inhibitors together. Taken together, these data indicate that 12/15LO enzyme activity causes activation of NF-B in apoEKO mouse aorta.
Activation of RhoA in ApoEKO Aortic EC
We have reported that 12/15LO transgenic mice have increased rhoA activation caused by increased 12SHETE production.28 Based on these previous data as well as the data in Figure 3, we directly examined activation of rhoA in both apoEKO and doubleKO aortic endothelium. RhoA activity was measured by affinity precipitation of active RhoA with the 
-binding domain of rhotekin as previously described.30 We found increased rhoA activation in apoEKO endothelium compared with doubleKO endothelium, which showed little or no rhoA activation (Figure 4). These data suggest that the activation of rhoA by the 12/15LO pathway in apoEKO mice significantly contributes to increased monocyte:EC interactions in these mice. Taken together, these data in Figures 3 and 4
illustrate that endothelial NF-B activation is most likely mediated through rhoA and PKC activation.
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Mechanisms Contributing to Accelerated Monocyte Adhesion by 12/15LO
We next examined whether the rho kinase inhibitor or the PKC inhibitor modulated ICAM-1 expression in apoEKO cells. Expression of ICAM-1 in MAEC was measured by quantitative real-time polymerase chain reaction. MAEC from apoEKO had significantly higher ICAM-1 expression than doubleKO (supplemental Figure IIA). Pretreament of apoEKO MAEC with the rho kinase inhibitor, the PKC inhibitor, or both compounds together significantly reduced ICAM-1 mRNA (P<0.0001). We also analyzed ICAM-1 surface expression in apoEKO and doubleKO MAEC by flow cytometry. ICAM-1 is constitutively expressed on endothelium; the percentage of ICAM-1 expression on EC ranged from 73% in doubleKO to 78% in apoEKO mouse EC. The mean fluorescence intensity (MFI) values indicated dramatic changes in ICAM-1 expression on EC. The MFI of doubleKO EC was 76, apoEKO was 151, apoEKO+Y27632 was 114, apoEKO+Go6976 was 123, and apoEKO+both inhibitors was 101. These data are illustrated graphically in supplemental Figure IIB. MAEC from doubleKO mice (shown in red) had significantly lower expression of ICAM-1 compared with apoEKO (shown in blue). Pretreatment of apoEKO MAEC with the PKC inhibitor (shown in orange), the rho kinase inhibitor (shown in turquoise), or both compounds together (shown in green) significantly reduced surface ICAM-1 (P<0.0001; supplemental Figure IIB).
RhoA and PKC Inhibition Decrease Monocyte Adhesion to Aorta of ApoEKO Mice
Finally, we directly tested whether inhibition of rhoA or PKC activation altered monocyte adhesion to aortic endothelium in apoEKO mice. Aortas were isolated from apoEKO and doubleKO mice and were used in an ex vivo monocyte adhesion assay. As shown in Figure 5a, there was a dramatic reduction (85%) in the number of monocytes bound to doubleKO endothelium compared with apoEKO endothelium. Treatment of apoEKO aortas for 4 hours with either the Rho kinase inhibitor or with the PKC inhibitor reduced monocyte adhesion by 70% (Figure 5a). Treatment of apoE aortas with both compounds together significantly reduced monocyte adhesion by 75% (Figure 5a and 5b). The use of both compounds blocked monocyte adhesion to a level similar as to that observed in the double KO mice (Figure 5a and 5b). Interestingly, neither the PKC inhibitor nor the rhoA inhibitor had any effect on monocyte adhesion in doubleKO aortas (Figure 5b), again supporting the concept that 12/15LO products signal through a rhoA/PKC pathway to mediate monocyte adhesion. These data indicate that rhoA and PKC signaling are involved in mediating monocyte:EC adhesion to apoE aorta.
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Discussion |
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The protein sequence of murine 12/15LO is most closely related to 15-LO in humans.31–33 Although these enzymes share similarity, and the mouse enzyme is referred to as "12/15LO," there are subtle differences in the enzymes, especially in their generation of eicosanoid products. Human 15-LO generates 15SHETE and 12SHETE at a ratio of 9:1, yet murine 12/15LO generates 15SHETE and 12SHETE at a ratio of 1:4.31,34 Most studies have reported 12SHETE to be pro-inflammatory,13,20,24,28,35–40 whereas the inflammatory role of 15SHETE is unclear. 15SHETE can serve as a substrate for 5-LO to generate anti-inflammatory lipoxins,41–43 and can also serve as a ligand for the nuclear hormone receptor PPAR
.44,45 Two studies in transgenic rabbits that overexpressed human 15-LO indicated that 15-LO expression reduced atherosclerosis development,46,47 whereas 2 other studies indicated that treatment of rabbits with 15-LO inhibitors reduced atherosclerosis progression.48,49 Although murine 12/15LO has been shown to mediate atherosclerosis development in mouse models of atherosclerosis, the exact mechanisms through which this occurs are unclear. Endothelial activation and subsequent monocyte recruitment and adhesion to aortic endothelium are key early events in atherosclerotic plaque initiation.50,51 In the current study, we show that monocyte:endothelial adhesion to apoEKO mouse aorta is dependent on 12/15LO activity in vivo. Inhibition of 12/15LO activity dramatically reduces monocyte adhesion to apoEKO aorta. Further, we show that a primary mechanism by which 12/15LO mediates monocyte adhesion to aortic endothelium is through upregulation of ICAM-1 through activation of a rhoA/NF-B signaling pathway.
We have previously reported that rhoA and PKC work synergistically in endothelium to activate NF-B in response to 12/15LO products.28 There are reports that RhoA and PKC work together in EC to regulate each other’s activity.52,53 Furthermore, inhibition of RhoA can block PKC translocation and activation in EC.52 Our previous data indicated that RhoA is upstream of PKC.28 Thus, our data indicate that 12/15LO products activate endothelial rhoA and PKC, which, in turn, activate NF-B to upregulate endothelial ICAM-1 expression. Upregulation of ICAM-1 by this signaling pathway stimulates monocyte:EC interactions. Our data further illustrate that this RhoA/NF-B signaling pathway is a primary regulator of aortic endothelial activation in apoEKO mice. Inhibition of 12/15LO activity in vivo in the apoEKO mouse, either through pharmacological inhibition by CDC (Figure 2) or through molecular gene targeting strategies by the use of knockout mice, prevents rhoA and NF-B activation, which subsequently prevents monocyte:EC adhesion in the apoEKO aorta.
The activation of endothelial rhoA by 12/15LO suggests that 12/15LO eicosanoid products bind to a specific G protein–coupled receptor on endothelium. We hypothesize that the 12/15LO eicosanoids are secreted by both activated endothelium and monocytes and bind to a specific G protein–coupled receptor on vascular cells, thus amplifying and prolonging the inflammatory response. A specific 12SHETE receptor has not yet been identified; however, Szekeres et al have reported the presence of putative low-affinity and high-affinity 12SHETE receptors in carcinoma cells.54 We have previously reported that G12/G13 signaling is involved in the activation of rhoA by 12SHETE in endothelium,28 further suggesting involvement of a G protein–coupled receptor. Studies to identify this receptor are currently ongoing in the laboratory.
The apoE-deficient mice that are also deficient in 12/15LO (double KO) have decreased expression of ICAM-1 on aortic endothelium compared with apoEKO mice (Figure 1 and supplemental Figure II). ICAM-1 has been strongly linked to atherosclerosis development.8,55,56 In the current study, we did not examine other adhesion molecules that are regulated by NF-B and rhoA. We reported several years ago that 12SHETE stimulated expression of connecting segment-1 (CS-1) fibronectin on the apical surface of human endothelium,20 and that CS-1 served as a counter-receptor for VLA-4 on monocytes.57 Thus, it is conceivable that apoEKO mouse aorta has significant expression of CS-1, whereas expression of CS-1 is reduced in the doubleKO mice. Based on our earlier in vitro data with CS-1, such a situation would significantly impact monocyte:EC interactions. Downregulation of rhoA has been found to impact the interactions of CS-1 with integrins.58 Reagents to accurately quantify CS-1 fibronectin expression in the mouse are not available, so we currently cannot rule out a contribution of CS-1.
We focused this present study on ICAM-1 expression in apoE-deficient mice in vivo, and the signaling mechanisms that contribute to increased ICAM-1 expression mediated by 12/15LO. The reasons that we focused exclusively on ICAM-1 are that we recently found that 12SHETE stimulates ICAM-1 expression in endothelium,28 and that ICAM-1 expression is increased in 12/15LO transgenic mice in vivo.24 However, VCAM-1 and E-selectin promote rolling and adhesion of monocytes along endothelium8,56,59–61 and both are regulated by NF-B.62–64 Therefore, it is quite conceivable that surface expression of these molecules is downregulated in 12/15LO-deficient mice. We have preliminary data to suggest that mRNA expression of VCAM-1 and E-selectin is not reduced in 12/15LO-deficient mice (data not shown), but we have not measured surface expression of these molecules by flow cytometry. Downregulation of VCAM-1 and E-selectin expression would result in decreased monocyte rolling and adhesion to endothelium. We anticipate that the reduction in monocyte adhesion to aortic endothelium in the absence of 12/15LO is not solely caused by ICAM-1, and that other adhesion molecules may contribute to this process.
We also cannot rule out changes in chemokine production in apoEKO versus doubleKO mice. Monocyte chemotactic protein-1 (MCP-1) is regulated by NFB activation and is secreted by activated endothelium.65–68 We have preliminary evidence to suggest that MCP-1 is increased by 12/15LO activity (data not shown). Lee et al have shown induction of MCP-1 by oxidized phospholipid components of LDL.69 The induction of MCP-1 by 12/15LO products and oxidized LDL cause increased monocyte recruitment to the activated aortic endothelium. Funk et al have shown that IL-12 signaling by macrophages is regulated by 12/15LO and is reduced in doubleKO mice.70 Thus, reductions in cytokine production in 12/15LO-deficient mice could certainly contribute to the reduction in monocyte adhesion to endothelium.
We previously examined the contribution of macrophage versus endothelial-derived 12/15LO eicosanoids as critical mediators of atherogenesis in apoE-deficient mice in vivo.40 We found that presence of 12/15LO in bone marrow-derived cells was critical for atherogenesis.40 However, we could not rule out contribution of endothelial 12/15LO in this process. Thus, we conclude that 12/15LO products, either monocyte-derived or endothelial-derived, can activate an endothelial surface receptor to cause endothelial activation via a rhoA/NF-B signaling cascade. This activation of endothelium by 12/15LO dramatically increases monocyte:endothelial adhesion, a key initiating event in atherosclerotic plaque development.
In summary, we report that 12/15LO is a critical mediator of monocyte adhesion to aorta of apoEKO mice in vivo. 12/15LO activity activates a rhoA/NF-B signaling pathway that results in the upregulation of ICAM-1 on the endothelial surface, thereby facilitating monocyte adhesion. Inhibition of 12/15LO activity in vivo in apoE-deficient mice dramatically reduces monocyte adhesion to aorta, indicating that the 12/15LO enzyme is a critical regulator of these processes in the vessel wall.
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Acknowledgments |
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This work was supported by NIH P01 HL55798 (Project 2; C.C.H.) and NIH R01 HL071141 (C.C.H). The authors thank Dr A. Wayne Orr (University of Virginia) for advice on rhoA signaling, Dr Rama Natarajan (Beckman Research Institute, City of Hope, Duarte, Calif) for advice on the CDC studies, and Dr Jerry L. Nadler (University of Virginia) and Dr Colin Funk (Queen’s University, Ontario, Canada) for the gift of the apoE–/–x12/15LO–/– mice.
Received January 8, 2006; accepted March 3, 2006.
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References |
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TopAbstractIntroductionMethodsResultsDiscussionReferences |
|---|
1. Witztum JL, Steinberg D. Role of oxidized low density lipoprotein in atherogenesis. J Clin Invest. 1991; 88: 1785–1792.[Medline] [Order article via Infotrieve]
2. Springer TA. Traffic signals on endothelium for lymphocyte recirculation and leukocyte emigration. Annu Rev Physiol. 1995; 57: 827–872.[CrossRef][Medline] [Order article via Infotrieve]
3. Butcher EC. Leukocyte-endothelial cell recognition: three (or more) steps to specificity and diversity. Cell. 1991; 67: 1033–1036.[CrossRef][Medline] [Order article via Infotrieve]
4. Gerrity RG. The role of the monocyte in atherogenesis: II. Migration of foam cells from atherosclerotic lesions. Am J Pathol. 1981; 103: 191–200.[Abstract]
5. Zhang SH, Reddick RL, Piedrahita JA, Maeda N. Spontaneous hypercholesterolemia and arterial lesions in mice lacking apolipoprotein E. Science. 1992; 258: 468–471.
6. Plump AS, Smith JD, Hayek T, Aalto-Setala K, Walsh A, Verstuyft JG, Rubin EM, Breslow JL. Severe hypercholesterolemia and atherosclerosis in apolipoprotein E- deficient mice created by homologous recombination in ES cells. Cell. 1992; 71: 343–353.[CrossRef][Medline] [Order article via Infotrieve]
7. Huo Y, Hafezi-Moghadam A, Ley K. Role of vascular cell adhesion molecule-1 and fibronectin connecting segment-1 in monocyte rolling and adhesion on early atherosclerotic lesions. Circ Res. 2000; 87: 153–159.
8. Ramos CL, Huo Y, Jung U, Ghosh S, Manka DR, Sarembock IJ, Ley K. Direct demonstration of P-selectin- and VCAM-1-dependent mononuclear cell rolling in early atherosclerotic lesions of apolipoprotein E- deficient mice. Circ Res. 1999; 84: 1237–1244.
9. Dansky HM, Barlow CB, Lominska C, Sikes JL, Kao C, Weinsaft J, Cybulsky MI, Smith JD. Adhesion of monocytes to arterial endothelium and initiation of atherosclerosis are critically dependent on vascular cell adhesion molecule-1 gene dosage. Arterioscler Thromb Vasc Biol. 2001; 21: 1662–1667.
10. Kitagawa K, Matsumoto M, Sasaki T, Hashimoto H, Kuwabara K, Ohtsuki T, Hori M. Involvement of ICAM-1 in the progression of atherosclerosis in APOE-knockout mice. Atherosclerosis. 2002; 160: 305–310.[CrossRef][Medline] [Order article via Infotrieve]
11. Yamamoto S, Suzuki H, Ueda N. Arachidonate 12-lipoxygenases. Prog Lipid Res. 1997; 36: 23–41.[CrossRef][Medline] [Order article via Infotrieve]
12. Brash AR. Lipoxygenases: occurrence, functions, catalysis, and acquisition of substrate. J Biol Chem. 1999; 274: 23679–23682.
13. Spector AA, Gordon JA, Moore SA. Hydroxyeicosatetraenoic acids (HETEs). Prog Lipid Res. 1988; 27: 271–323.[CrossRef][Medline] [Order article via Infotrieve]
14. Funk CD, Cyrus T. 12/15-lipoxygenase, oxidative modification of LDL and atherogenesis. Trends Cardiovasc Med. 2001; 11: 116–124.[CrossRef][Medline] [Order article via Infotrieve]
15. Sigari F, Lee C, Witztum JL, Reaven PD. Fibroblasts that overexpress 15-lipoxygenase generate bioactive and minimally modified LDL. Arterioscler Thromb Vasc Biol. 1997; 17: 3639–3645.
16. Honda HM, Leitinger N, Frankel M, Goldhaber JI, Natarajan R, Nadler JL, Weiss JN, Berliner JA. Induction of monocyte binding to endothelial cells by MM-LDL: role of lipoxygenase metabolites. Arterioscler Thromb Vasc Biol. 1999; 19: 680–686.
17. McNally AK, Chisolm GM III, Morel DW, Cathcart MK. Activated human monocytes oxidize low-density lipoprotein by a lipoxygenase-dependent pathway. J Immunol. 1990; 145: 254–259.[Abstract]
18. Yla-Herttuala S, Rosenfeld ME, Parthasarathy S, Glass CK, Sigal E, Witztum JL, Steinberg D. Colocalization of 15-lipoxygenase mRNA and protein with epitopes of oxidized low density lipoprotein in macrophage-rich areas of atherosclerotic lesions. Proc Natl Acad Sci U S A. 1990; 87: 6959–6963.
19. Yla-Herttuala S, Rosenfeld ME, Parthasarathy S, Sigal E, Sarkioja T, Witztum JL, Steinberg D. Gene expression in macrophage-rich human atherosclerotic lesions. 15-lipoxygenase and acetyl low density lipoprotein receptor messenger RNA colocalize with oxidation specific lipid-protein adducts. J Clin Invest. 1991; 87: 1146–1152.[Medline] [Order article via Infotrieve]
20. Patricia MK, Kim JA, Harper CM, Shih PT, Berliner JA, Natarajan R, Nadler JL, Hedrick CC. Lipoxygenase products increase monocyte adhesion to human aortic endothelial cells. Arterioscler Thromb Vasc Biol. 1999; 19: 2615–2622.
21. Patricia MK, Natarajan R, Dooley AN, Hernandez F, Gu JL, Berliner JA, Rossi JJ, Nadler JL, Meidell RS, Hedrick CC. Adenoviral delivery of a leukocyte-type 12 lipoxygenase ribozyme inhibits effects of glucose and platelet-derived growth factor in vascular endothelial and smooth muscle cells. Circ Res. 2001; 88: 659–665.
22. Cyrus T, Witztum JL, Rader DJ, Tangirala R, Fazio S, Linton MF, Funk CD. Disruption of the 12/15-lipoxygenase gene diminishes atherosclerosis in apo E-deficient mice. J Clin Invest. 1999; 103: 1597–1604.[Medline] [Order article via Infotrieve]
23. George J, Afek A, Shaish A, Levkovitz H, Bloom N, Cyrus T, Zhao L, Funk CD, Sigal E, Harats D. 12/15-Lipoxygenase gene disruption attenuates atherogenesis in LDL receptor-deficient mice. Circulation. 2001; 104: 1646–1650.
24. Reilly KB, Srinivasan S, Hatley ME, Patricia MK, Lannigan J, Bolick DT, Vandenhoff G, Pei H, Natarajan R, Nadler JL, Hedrick CC. 12/15-lipoxygenase activity mediates inflammatory monocyte/endothelial interactions and atherosclerosis in vivo. J Biol Chem. 2004; 279: 9440–9450.
25. Ma J, Natarajan R, LaPage J, Lanting L, Kim N, Becerra D, Clemmons B, Nast CC, Surya Prakash GK, Mandal M, Adler SG. 12/15-lipoxygenase inhibitors in diabetic nephropathy in the rat. Prostaglandins Leukot Essent Fatty Acids. 2005; 72: 13–20.[CrossRef][Medline] [Order article via Infotrieve]
26. Perona R, Montaner S, Saniger L, Sanchez-Perez I, Bravo R, Lacal JC. Activation of the nuclear factor-kappaB by Rho, CDC42, and Rac-1 proteins. Genes Dev. 1997; 11: 463–475.
27. Read MA, Whitley MZ, Gupta S, Pierce JW, Best J, Davis RJ, Collins T. Tumor necrosis factor alpha-induced E-selectin expression is activated by the nuclear factor-kappaB and c-JUN N-terminal kinase/p38 mitogen- activated protein kinase pathways. J Biol Chem. 1997; 272: 2753–2761.
28. Bolick DT, Orr AW, Whetzel A, Srinivasan S, Hatley ME, Schwartz MA, Hedrick CC. 12/15-lipoxygenase regulates intercellular adhesion molecule-1 expression and monocyte adhesion to endothelium through activation of RhoA and nuclear factor-kappaB. Arterioscler Thromb Vasc Biol. 2005; 25: 2301–2307.
29. Hippenstiel S, Schmeck B, Seybold J, Krull M, Eichel-Streiber C, Suttorp N. Reduction of tumor necrosis factor-alpha (TNF-alpha) related nuclear factor-kappaB (NF-kappaB) translocation but not inhibitor kappa-B (Ikappa-B)-degradation by Rho protein inhibition in human endothelial cells. Biochem Pharmacol. 2002; 64: 971–977.[CrossRef][Medline] [Order article via Infotrieve]
30. Ren XD, Schwartz MA. Determination of GTP loading on Rho. Methods Enzymol. 2000; 325: 264–272.[Medline] [Order article via Infotrieve]
31. Funk CD. The molecular biology of mammalian lipoxygenases and the quest for eicosanoid functions using lipoxygenase-deficient mice. Biochim Biophys Acta. 1996; 1304: 65–84.[Medline] [Order article via Infotrieve]
32. Funk CD, Chen XS, Johnson EN, Zhao L. Lipoxygenase genes and their targeted disruption. Prostaglandins Other Lipid Mediat. 2002; 68–69: 303–312.
33. Johnson EN, Sun D, Chen XS, Funk CD. Lipoxygenase gene disruption studies. Status and applications. Adv Exp Med Biol. 1999; 447: 63–73.[Medline] [Order article via Infotrieve]
34. Sloane DL, Leung R, Barnett J, Craik CS, Sigal E. Conversion of human 15-lipoxygenase to an efficient 12-lipoxygenase: the side-chain geometry of amino acids 417 and 418 determine positional specificity. Protein Eng. 1995; 8: 275–282.
35. Chopra H, Timar J, Chen YQ, Rong XH, Grossi IM, Fitzgerald LA, Taylor JD, Honn KV. The lipoxygenase metabolite 12(S)-HETE induces a cytoskeleton-dependent increase in surface expression of integrin alpha IIb beta 3 on melanoma cells. Int J Cancer. 1991; 49: 774–786.[Medline] [Order article via Infotrieve]
36. Stenson WF, Parker CW. Monohydroxyeicosatetraenoic acids (HETEs) induce degranulation of human neutrophils. J Immunol. 1980; 124: 2100–2104.[Abstract]
37. Szekeres CK, Trikha M, Honn KV. 12(S)-HETE, pleiotropic functions, multiple signaling pathways. Adv Exp Med Biol. 2002; 507: 509–515.[Medline] [Order article via Infotrieve]
38. Tang DG, Renaud C, Stojakovic S, Diglio CA, Porter A, Honn KV. 12(S)-HETE is a mitogenic factor for microvascular endothelial cells: its potential role in angiogenesis. Biochem Biophys Res Commun. 1995; 211: 462–468.[CrossRef][Medline] [Order article via Infotrieve]
39. Hedrick CC, Kim MD, Natarajan RD, Nadler JL. 12-Lipoxygenase products increase monocyte: endothelial interactions. Adv Exp Med Biol. 1999; 469: 455–460.[Medline] [Order article via Infotrieve]
40. Huo Y, Zhao L, Hyman MC, Shashkin P, Harry BL, Burcin T, Forlow SB, Stark MA, Smith DF, Clarke S, Srinivasan S, Hedrick CC, Pratico D, Witztum JL, Nadler JL, Funk CD, Ley K. Critical role of macrophage 12/15-lipoxygenase for atherosclerosis in apolipoprotein E-deficient mice. Circulation. 2004; 110: 2024–2031.
41. Chiang N, Arita M, Serhan CN. Anti-inflammatory circuitry: lipoxin, aspirin-triggered lipoxins and their receptor ALX. Prostaglandins Leukot Essent Fatty Acids. 2005; 73: 163–177.[CrossRef][Medline] [Order article via Infotrieve]
42. Serhan CN, Drazen JM. Antiinflammatory potential of lipoxygenase-derived eicosanoids: a molecular switch at 5 and 15 positions? J Clin Invest. 1997; 99: 1147–1148.[Medline] [Order article via Infotrieve]
43. Serhan CN. Lipoxins and aspirin-triggered 15-epi-lipoxins are the first lipid mediators of endogenous anti-inflammation and resolution. Prostaglandins Leukot Essent Fatty Acids. 2005; 73: 141–162.[CrossRef][Medline] [Order article via Infotrieve]
44. Shappell SB, Gupta RA, Manning S, Whitehead R, Boeglin WE, Schneider C, Case T, Price J, Jack GS, Wheeler TM, Matusik RJ, Brash AR, DuBois RN. 15S-Hydroxyeicosatetraenoic acid activates peroxisome proliferator-activated receptor gamma and inhibits proliferation in PC3 prostate carcinoma cells. Cancer Res. 2001; 61: 497–503.
45. Ricote M, Welch JS, Glass CK. Regulation of macrophage gene expression by the peroxisome proliferator-activated receptor-gamma. Horm Res. 2000; 54: 275–280.[CrossRef][Medline] [Order article via Infotrieve]
46. Serhan CN, Jain A, Marleau S, Clish C, Kantarci A, Behbehani B, Colgan SP, Stahl GL, Merched A, Petasis NA, Chan L, Van Dyke TE. Reduced inflammation and tissue damage in transgenic rabbits overexpressing 15-lipoxygenase and endogenous anti-inflammatory lipid mediators. J Immunol. 2003; 171: 6856–6865.
47. Shen J, Herderick E, Cornhill JF, Zsigmond E, Kim HS, Kuhn H, Guevara NV, Chan L. Macrophage-mediated 15-lipoxygenase expression protects against atherosclerosis development. J Clin Invest. 1996; 98: 2201–2208.[Medline] [Order article via Infotrieve]
48. Sendobry SM, Cornicelli JA, Welch K, Bocan T, Tait B, Trivedi BK, Colbry N, Dyer RD, Feinmark SJ, Daugherty A. Attenuation of diet-induced atherosclerosis in rabbits with a highly selective 15-lipoxygenase inhibitor lacking significant antioxidant properties. Br J Pharmacol. 1997; 120: 1199–1206.[CrossRef][Medline] [Order article via Infotrieve]
49. Bocan TM, Rosebury WS, Mueller SB, Kuchera S, Welch K, Daugherty A, Cornicelli JA. A specific 15-lipoxygenase inhibitor limits the progression and monocyte-macrophage enrichment of hypercholesterolemia-induced atherosclerosis in the rabbit. Atherosclerosis. 1998; 136: 203–216.[CrossRef][Medline] [Order article via Infotrieve]
50. Berliner JA, Parhami F, Fang ZT, Fogelman AM, Territo C Regulation of monocyte and neutrophil entry into the vessel wall. Behring Inst Mitt. 1993; 87–91.
51. Navab M, Berliner JA, Watson AD, Hama SY, Territo MC, Lusis AJ, Shih DM, Van Lenten BJ, Frank JS, Demer LL, Edwards PA, Fogelman AM. The Yin and Yang of oxidation in the development of the fatty streak. A review based on the 1994 George Lyman Duff Memorial Lecture. Arterioscler Thromb Vasc Biol. 1996; 16: 831–842.
52. Barandier C, Ming XF, Rusconi S, Yang ZH. PKC is required for activation of ROCK by RhoA in human endothelial cells. Biochem Biophys Res Commun. 2003; 304: 714–719.[CrossRef][Medline] [Order article via Infotrieve]
53. Hippenstiel S, Kratz T, Krull M, Seybold J, Eichel-Streiber C, Suttorp N. Rho protein inhibition blocks protein kinase C translocation and activation. Biochem Biophys Res Commun. 1998; 245: 830–834.[CrossRef][Medline] [Order article via Infotrieve]
54. Szekeres CK, Tang K, Trikha M, Honn KV. Eicosanoid activation of extracellular signal-regulated kinase1/2 in human epidermoid carcinoma cells. J Biol Chem. 2000; 275: 38831–38841.
55. Kevil CG, Patel RP, Bullard DC. Essential role of ICAM-1 in mediating monocyte adhesion to aortic endothelial cells. Am J Physiol Cell Physiol. 2001; 281: C1442–C1447.
56. Ley K, Huo Y. VCAM-1 is critical in atherosclerosis. J Clin Invest. 2001; 107: 1209–1210.[Medline] [Order article via Infotrieve]
57. Shih PT, Elices MJ, Fang ZT, Ugarova TP, Strahl D, Territo MC, Frank JS, Kovach NL, Cabanas C, Berliner JA, Vora DK. Minimally modified low-density lipoprotein induces monocyte adhesion to endothelial connecting segment-1 by activating beta1 integrin. J Clin Invest. 1999; 103: 613–625.[Medline] [Order article via Infotrieve]
58. Moyano JV, Maqueda A, Casanova B, Garcia-Pardo A. Alpha4beta1 integrin/ligand interaction inhibits alpha5beta1-induced stress fibers and focal adhesions via down-regulation of RhoA and induces melanoma cell migration. Mol Biol Cell. 2003; 14: 3699–3715.
59. Ley K, Tedder TF. Leukocyte interactions with vascular endothelium. New insights into selectin-mediated attachment and rolling. J Immunol. 1995; 155: 525–528.[Abstract]
60. Lorenzon P, Vecile E, Nardon E, Ferrero E, Harlan JM, Tedesco F, Dobrina A. Endothelial cell E- and P-selectin and vascular cell adhesion molecule-1 function as signaling receptors. J Cell Biol. 1998; 142: 1381–1391.
61. Carlos TM, Harlan JM. Leukocyte-endothelial adhesion molecules. Blood. 1994; 84: 2068–2101.
62. Collins T, Read MA, Neish AS, Whitley MZ, Thanos D, Maniatis T. Transcriptional regulation of endothelial cell adhesion molecules: NF-kappa B and cytokine-inducible enhancers. FASEB J. 1995; 9: 899–909.[Abstract]
63. Morigi M, Angioletti S, Imberti B, Donadelli R, Micheletti G, Figliuzzi M, Remuzzi A, Zoja C, Remuzzi G. Leukocyte-endothelial interaction is augmented by high glucose concentrations and hyperglycemia in a NF-kB-dependent fashion. J Clin Invest. 1998; 101: 1905–1915.[Medline] [Order article via Infotrieve]
64. Rival Y, Beneteau N, Taillandier T, Pezet M, Dupont-Passelaigue E, Patoiseau JF, Junquero D, Colpaert FC, Delhon A. PPARalpha and PPARdelta activators inhibit cytokine-induced nuclear translocation of NF-kappaB and expression of VCAM-1 in EAhy926 endothelial cells. Eur J Pharmacol. 2002; 435: 143–151.[CrossRef][Medline] [Order article via Infotrieve]
65. Conti P, DiGioacchino M. MCP-1 and RANTES are mediators of acute and chronic inflammation. Allergy Asthma Proc. 2001; 22: 133–137.[Medline] [Order article via Infotrieve]
66. Gerszten RE, Garcia-Zepeda EA, Lim YC, Yoshida M, Ding HA, Gimbrone MA, Jr., Luster AD, Luscinskas FW, Rosenzweig A. MCP-1 and IL-8 trigger firm adhesion of monocytes to vascular endothelium under flow conditions. Nature. 1999; 398: 718–723.[CrossRef][Medline] [Order article via Infotrieve]
67. Ley K. Arrest chemokines. Microcirculation. 2003; 10: 289–295.[CrossRef][Medline] [Order article via Infotrieve]
68. Martin T, Cardarelli PM, Parry GC, Felts KA, Cobb RR. Cytokine induction of monocyte chemoattractant protein-1 gene expression in human endothelial cells depends on the cooperative action of NF-kappa B and AP-1. Eur J Immunol. 1997; 27: 1091–1097.[Medline] [Order article via Infotrieve]
69. Lee H, Shi W, Tontonoz P, Wang S, Subbanagounder G, Hedrick CC, Hama S, Borromeo C, Evans RM, Berliner JA, Nagy L. Role for peroxisome proliferator-activated receptor alpha in oxidized phospholipid-induced synthesis of monocyte chemotactic protein-1 and interleukin-8 by endothelial cells. Circ Res. 2000; 87: 516–521.
70. Zhao L, Cuff CA, Moss E, Wille U, Cyrus T, Klein EA, Pratico D, Rader DJ, Hunter CA, Pure E, Funk CD. Selective interleukin-12 synthesis defect in 12/15-lipoxygenase-deficient macrophages associated with reduced atherosclerosis in a mouse model of familial hypercholesterolemia. J Biol Chem. 2002; 277: 35350–35356.
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