scholarly journals Accelerated atherogenesis and neointima formation in heparin cofactor II–deficient mice

Blood ◽  
2007 ◽  
Vol 110 (13) ◽  
pp. 4261-4267 ◽  
Author(s):  
Cristina P. Vicente ◽  
Li He ◽  
Douglas M. Tollefsen
Keyword(s):  
Carotid Artery ◽  
Dermatan Sulfate ◽  
Plasma Lipid ◽  
Atherogenic Diet ◽  
Dependent Manner ◽  
Neointima Formation ◽  
Wild Type ◽  
Heparin Cofactor Ii ◽  
Glucose Levels ◽  
Deficient Mice

Heparin cofactor II (HCII) is a plasma protein that inhibits thrombin when bound to dermatan sulfate or heparin. HCII-deficient mice are viable and fertile but rapidly develop thrombosis of the carotid artery after endothelial injury. We now report the effects of HCII deficiency on atherogenesis and neointima formation. HCII-null or wild-type mice, both on an apolipoprotein E–null background, were fed an atherogenic diet for 12 weeks. HCII-null mice developed plaque areas in the aortic arch approximately 64% larger than wild-type mice despite having similar plasma lipid and glucose levels. Neointima formation was induced by mechanical dilation of the common carotid artery. Thrombin activity, determined by hirudin binding or chromogenic substrate hydrolysis within 1 hour after injury, was higher in the arterial walls of HCII-null mice than in wild-type mice. After 3 weeks, the median neointimal area was 2- to 3-fold greater in HCII-null than in wild-type mice. Dermatan sulfate administered intravenously within 48 hours after injury inhibited neointima formation in wild-type mice but had no effect in HCII-null mice. Heparin did not inhibit neointima formation. We conclude that HCII deficiency promotes atherogenesis and neointima formation and that treatment with dermatan sulfate reduces neointima formation in an HCII-dependent manner.

Antithrombotic activity of dermatan sulfate in heparin cofactor II-deficient mice

Blood ◽  
2004 ◽  
Vol 104 (13) ◽  
pp. 3965-3970 ◽  
Author(s):  
Cristina P. Vicente ◽  
Li He ◽  
Mauro S. G. Pavão ◽  
Douglas M. Tollefsen
Keyword(s):  
Carotid Artery ◽  
Dermatan Sulfate ◽  
Wild Type ◽  
Antithrombotic Effect ◽  
Porcine Skin ◽  
Heparin Cofactor Ii ◽  
Thrombotic Occlusion ◽  
Antithrombotic Activity ◽  
Occlusion Time ◽  
Deficient Mice

Abstract Heparin cofactor II (HCII) is a plasma protein that inhibits thrombin rapidly in the presence of dermatan sulfate or heparin. We previously reported that the time to thrombotic occlusion of the carotid artery after photochemical injury was shorter in HCII-deficient mice than in wild-type control animals. In this paper, we describe the antithrombotic activity of dermatan sulfate in wild-type and HCII-deficient mice. Intravenous administration of porcine skin dermatan sulfate induced a dose-dependent prolongation of the carotid artery occlusion time in HCII+/+ mice that was not observed in HCII-/- animals. Pharmacokinetic studies suggested that porcine skin dermatan sulfate expresses antithrombotic activity after being transferred from the plasma to sites in the vessel wall. Using invertebrate dermatan sulfate preparations, we showed that N-acetylgalactosamine-4-O-sulfate residues are required for the HCII-dependent antithrombotic effect. Furthermore, the invertebrate dermatan sulfates, which have higher charge densities than mammalian dermatan sulfate, slightly prolonged the thrombotic occlusion time of HCII-/- mice. These results indicate that HCII mediates the antithrombotic effect of porcine skin dermatan sulfate after injury to the carotid arterial endothelium in mice, whereas more highly charged dermatan sulfates possess weak antithrombotic activity independent of HCII. (Blood. 2004;104:3965-3970)

scholarly journals Vascular dermatan sulfate regulates the antithrombotic activity of heparin cofactor II

Blood ◽  
2008 ◽  
Vol 111 (8) ◽  
pp. 4118-4125 ◽  
Author(s):  
Li He ◽  
Tusar K. Giri ◽  
Cristina P. Vicente ◽  
Douglas M. Tollefsen
Keyword(s):  
Carotid Artery ◽  
Dermatan Sulfate ◽  
Thrombus Formation ◽  
Wild Type ◽  
Heparin Cofactor Ii ◽  
Arterial Endothelium ◽  
Carotid Arterial ◽  
Deficient Mice

AbstractHeparin cofactor II (HCII)–deficient mice form occlusive thrombi more rapidly than do wild-type mice following injury to the carotid arterial endothelium. Dermatan sulfate (DS) and heparan sulfate (HS) increase the rate of inhibition of thrombin by HCII in vitro, but it is unknown whether vascular glycosaminoglycans play a role in the antithrombotic effect of HCII in vivo. In this study, we found that intravenous injection of either wild-type recombinant HCII or a variant with low affinity for HS (K173H) corrected the abnormally short thrombosis time of HCII-deficient mice, while a variant with low affinity for DS (R189H) had no effect. When HCII was incubated with frozen sections of the mouse carotid artery, it bound specifically to DS in the adventitia. HCII was undetectable in the wall of the uninjured carotid artery, but it became concentrated in the adventitia following endothelial injury. These results support the hypothesis that HCII interacts with DS in the vessel wall after disruption of the endothelium and that this interaction regulates thrombus formation in vivo.

Abstract 307: Deficiency of Lim-only Protein Fhl2 Accelerates Neointima Formation After Carotid Artery Ligation

2013 ◽  
Vol 33 (suppl_1) ◽  
Author(s):  
Kondababu Kurakula ◽  
Vivian de Waard ◽  
Claudia M van Tiel ◽  
Carlie J de Vries
Keyword(s):  
Carotid Artery ◽  
Vascular Injury ◽  
Regulatory Function ◽  
Dependent Manner ◽  
Neointima Formation ◽  
Wild Type ◽  
Lesion Formation ◽  
Artery Ligation ◽  
Carotid Artery Ligation ◽  
Enhanced Expression

Rationale The LIM-only protein FHL2, also known as DRAL or SLIM3, has a regulatory function in many physiological processes and is expressed in the vessel wall in smooth muscle cells (SMCs) and endothelial cells, but not in macrophages. FHL2 regulates SMC phenotype, but its function in vascular injury is unknown. Objective To assess the role of FHL2 in SMC-rich lesion formation after vascular injury and to elucidate the underlying mechanism. Methods & Results Cultured aortic SMCs from FHL2-KO mice showed increased migration and increased proliferation through enhanced phosphorylation of extracellular-regulated kinase-1/2 (ERK1/2) and induction of CyclinD1 expression. In agreement with this, overexpression of FHL2 in SMCs reduced CyclinD1 expression. In addition, FHL2-KO SMCs showed enhanced expression of pro-inflammatory cytokines in a NFkB dependent manner. Consistent with these findings, NFkB activity is higher in FHL2-KO SMCs. In response to carotid artery ligation FHL2-deficient (FHL2-KO) mice developed accelerated lesion formation compared with wild-type (WT)-mice. Furthermore, FHL2-KO mice displayed high number of macrophages in lesions and enhanced expression of RANTES and stromal derived factor-1α (SDF-1α) in ligated carotid arteries. SDF-1α expression was also increased in plasma of FHL2-KO mice. Finally, FHL2-KO mice showed enhanced Ki67 expression in lesions compared with wild-type (WT)-mice. Conclusion FHL2 deficiency in mice results in an exacerbated neointima formation by enhanced proliferation and migration of SMCs, possibly regulated via ERK1/2 and NFkB pathway.

Trif is not required for immune complex glomerulonephritis: dying cells activate mesangial cells via Tlr2/Myd88 rather than Tlr3/Trif

2009 ◽  
Vol 296 (4) ◽  
pp. F867-F874 ◽  
Author(s):  
Julia Lichtnekert ◽  
Volker Vielhauer ◽  
Daniel Zecher ◽  
Onkar P. Kulkarni ◽  
Sebastian Clauss ◽  
...  
Keyword(s):  
Mesangial Cells ◽  
Apoptotic Cell ◽  
Dependent Manner ◽  
Glomerular Mesangial Cells ◽  
Wild Type ◽  
Tlr Agonists ◽  
Rabbit Igg ◽  
Dying Cells ◽  
Myd88 Signaling ◽  
Deficient Mice

Viral RNA or bacterial products can activate glomerular mesangial cells via a subset of Toll-like receptors (Tlr). Because Tlr2-deficient mice were recently found to have attenuated nephrotoxic serum nephritis (NSN), we hypothesized that endogenous Tlr agonists can activate glomerular mesangial cells. Primary mesangial cells from C57BL/6 mice expressed Tlr1-6 and Tlr11 mRNA at considerable levels and produced Il-6 when being exposed to the respective Tlr ligands. Exposure to necrotic cells activated cultured primary mesangial cells to produce Il-6 in a Tlr2/Myd88-dependent manner. Apoptotic cells activated cultured mesangial cells only when being enriched to high numbers. Apoptotic cell-induced Il-6 release was Myd88 dependent, and only purified apoptotic cell RNA induced Trif signaling in mesangial cells. Does Trif signaling contribute to disease activity in glomerulonephritis? To answer this question, we induced autologous NSN by injection of NS raised in rabbits in Trif-mutant and wild-type mice. Lack of Trif did not alter the functional and histomorphological abnormalities of NSN, including the evolution of anti-rabbit IgG and anti-rabbit-specific nephritogenic T cells. We therefore conclude that apoptotic cell RNA is a poor activator of Trif signaling in mesangial cells and that necrotic cells' releases rather activate mesangial cells via the Tlr2/Myd88 signaling pathway.

scholarly journals Cardiac hypertrophy and decreased high-density lipoprotein cholesterol in Lrig3-deficient mice

2016 ◽  
Vol 310 (11) ◽  
pp. R1045-R1052 ◽  
Author(s):  
Martin Hellström ◽  
Madelene Ericsson ◽  
Bengt Johansson ◽  
Mahmood Faraz ◽  
Fredrick Anderson ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Cardiac Hypertrophy ◽  
High Density Lipoprotein ◽  
Heart Function ◽  
Plasma Lipid ◽  
Density Lipoprotein ◽  
Hdl Cholesterol ◽  
Wild Type ◽  
Lipid Levels ◽  
Deficient Mice

Genetic factors confer risk for cardiovascular disease. Recently, large genome-wide population studies have shown associations between genomic loci close to LRIG3 and heart failure and plasma high-density lipoprotein (HDL) cholesterol level. Here, we ablated Lrig3 in mice and investigated the importance of Lrig3 for heart function and plasma lipid levels. Quantitative reverse transcription-polymerase chain reaction (RT-PCR) was used to analyze Lrig3 expression in the hearts of wild-type and Lrig3-deficient mice. In addition, molecular, physiological, and functional parameters such as organ weights, heart rate, blood pressure, heart structure and function, gene expression in the heart, and plasma insulin, glucose, and lipid levels were evaluated. The Lrig3-deficient mice were smaller than the wild-type mice but otherwise appeared grossly normal. Lrig3 was expressed at detectable but relatively low levels in adult mouse hearts. At 9 mo of age, ad libitum-fed Lrig3-deficient mice had lower insulin levels than wild-type mice. At 12 mo of age, Lrig3-deficient mice exhibited increased blood pressure, and the Lrig3-deficient female mice displayed signs of cardiac hypertrophy as assessed by echocardiography, heart-to-body weight ratio, and expression of the cardiac hypertrophy marker gene Nppa. Additionally, Lrig3-deficient mice had reduced plasma HDL cholesterol and free glycerol. These findings in mice complement the human epidemiological results and suggest that Lrig3 may influence heart function and plasma lipid levels in mice and humans.

Lactadherin and Clearance of Platelet-Derived Microvesicles.

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 1840-1840
Author(s):  
Swapan Kumar Dasgupta ◽  
Hanan Abdel-Monem ◽  
Polly Niravath ◽  
Anhquyen Le ◽  
Ricardo Bellera ◽  
...  
Keyword(s):  
Milk Fat ◽  
Mammalian Cells ◽  
Procoagulant Activity ◽  
In Vivo Model ◽  
Maximal Effect ◽  
Dependent Manner ◽  
Wild Type ◽  
Membrane Bilayer ◽  
Anionic Phospholipids ◽  
Deficient Mice

Abstract Objective— In platelets, as in most mammalian cells, the anionic phospholipids such as phosphatidylserine are present only in the inner leaflet of the membrane bilayer. During platelet activation, phosphatidylserine moves from the inner to the outer leaflet of the membrane bilayer. The transbilayer movement of phosphatidylserine is responsible for platelet procoagulant activity as the exposed phosphatidylserine provides high affinity binding sites for the assembly of the prothrombinase and tenase complex. Externalization of anionic phospholipids in platelet is accompanied by the release of phosphatidylserine-rich microvesicles. These microvesicles account for the procoagulant activity of plasma by providing an efficient catalytic surface. Lactadherin, also known milk fat globule-EGF 8, is a 45 kDa glycoprotein secreted by macrophages. Lactadherin contains EGF-like domains at the amino terminus and two C-domains at the carboxy terminus that share homology to the phosphatidylserinebinding domains of blood coagulation factors V and VIII. Lactadherin binds to apoptotic lymphocytes and phosphatidylserine-expressing red blood cells via the C-domains and anchors them to macrophage integrins via its RGD sequence in the EGF domain. We have examined the role of lactadherin in clearance of phosphatidylserine-rich platelet-derived microvesicles. Methods and Results—Platelet-derived microvesicles were labeled with the fluorophore BODIPY-maleimide and incubated with THP-1 cell derived macrophages. The extent of phagocytosis was quantified by measuring the intracellular fluorescence by flow cytometry. Lactadherin promoted phagocytosis in a concentration-dependent manner with a half-maximal effect at ~ 5 ng/ml. A monoclonal antibody to lactadherin and a carboxy terminal fragment of lactadherin inhibited lactadherin-dependent phagocytosis. Lactadherin-deficient mice had increased number of microvesicles in their plasma and generated more thrombin compared to their wild type littermates. In addition, splenic macrophages from lactadherin-deficient mice showed decreased capacity to phagocytose platelet microvesicles. Finally, in a in vivo model of light/dye-induced endothelial injury/ thrombosis model, lactadherin-deficient mice, showed enhanced thrombus formation (5.93 ± 0.43 min) compared to their wild-type littermates ( 9.80 ± 1.14 min; P=0.01, n=9 in each group) in the cremastric venules. Conclusion— Our studies show that lactadherin mediates the clearance of PS expressing platelet-derived microvesicles from the circulation and that a defective clearance can induce a hypercoagulable state.

Platelet endothelial cell adhesion molecule-1 is a negative regulator of platelet-collagen interactions

Blood ◽  
2001 ◽  
Vol 98 (5) ◽  
pp. 1456-1463 ◽  
Author(s):  
Karen L. Jones ◽  
Sascha C. Hughan ◽  
Sacha M. Dopheide ◽  
Richard W. Farndale ◽  
Shaun P. Jackson ◽  
...  
Keyword(s):  
Cell Adhesion Molecule ◽  
Collagen Matrix ◽  
Negative Regulator ◽  
Dependent Manner ◽  
Wild Type ◽  
Platelet Endothelial Cell Adhesion ◽  
Cell Adhesion Molecule 1 ◽  
Dose Dependent ◽  
Deficient Mice ◽  
Endothelial Cell Adhesion

The functional importance of platelet endothelial cell adhesion molecule-1 (PECAM-1/CD31) in platelets is unclear. Because PECAM-1 represents a newly assigned immunoglobulin–ITIM superfamily member expressed on the surface of platelets, it was hypothesized that it may play an important regulatory role in modulating ITAM-bearing receptors such as collagen (GP)VI receptor and FcγRIIA. To examine the functional role of PECAM-1 in regulating platelet-collagen interactions, 2 different approaches were applied using recombinant human PECAM-1–immunoglobulin chimeras and platelets derived from PECAM-1–deficient mice. Stimulation of platelets by collagen-, (GP)VI-selective agonist, collagen-related peptide (CRP)–, and PECAM-1–immunoglobulin chimera induced tyrosine phosphorylation of PECAM-1 in a time- and dose-dependent manner. Activation of PECAM-1 directly through the addition of soluble wild-type PECAM-1–immunoglobulin chimera, but not mutant K89A PECAM-1–immunoglobulin chimera that prevents homophilic binding, was found to inhibit collagen- and CRP-induced platelet aggregation. PECAM-1–deficient platelets displayed enhanced platelet aggregation and secretion responses on stimulation with collagen and CRP, though the response to thrombin was unaffected. Under conditions of flow, human platelet thrombus formation on a collagen matrix was reduced in a dose-dependent manner by human PECAM-1–immunoglobulin chimera. Platelets derived from PECAM-1–deficient mice form larger thrombi when perfused over a collagen matrix under flow at a shear rate of 1800 seconds−1 compared to wild-type mice. Collectively, these results indicate that PECAM-1 serves as a physiological negative regulator of platelet-collagen interactions that may function to negatively limit growth of platelet thrombi on collagen surfaces.

Palmitoleic acid (n-7) increases white adipocyte lipolysis and lipase content in a PPARα-dependent manner

2013 ◽  
Vol 305 (9) ◽  
pp. E1093-E1102 ◽  
Author(s):  
Andressa Bolsoni-Lopes ◽  
William T. Festuccia ◽  
Talita S. M. Farias ◽  
Patricia Chimin ◽  
Francisco L. Torres-Leal ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Palmitoleic Acid ◽  
Whole Body ◽  
Mrna Levels ◽  
Dependent Manner ◽  
Wild Type ◽  
Acid Incorporation ◽  
Gene And Protein Expression ◽  
Fatty Acid Incorporation ◽  
Deficient Mice

We investigated whether palmitoleic acid, a fatty acid that enhances whole body glucose disposal and suppresses hepatic steatosis, modulates triacylglycerol (TAG) metabolism in adipocytes. For this, both differentiated 3T3-L1 cells treated with either palmitoleic acid (16:1n7, 200 μM) or palmitic acid (16:0, 200 μM) for 24 h and primary adipocytes from wild-type or PPARα-deficient mice treated with 16:1n7 (300 mg·kg−1·day−1) or oleic acid (18:1n9, 300 mg·kg−1·day−1) by gavage for 10 days were evaluated for lipolysis, TAG, and glycerol 3-phosphate synthesis and gene and protein expression profile. Treatment of differentiated 3T3-L1 cells with 16:1n7, but not 16:0, increased basal and isoproterenol-stimulated lipolysis, mRNA levels of adipose triglyceride lipase (ATGL) and hormone-sensitive lipase (HSL) and protein content of ATGL and pSer660-HSL. Such increase in lipolysis induced by 16:1n7, which can be prevented by pharmacological inhibition of PPARα, was associated with higher rates of PPARα binding to DNA. In contrast to lipolysis, both 16:1n7 and 16:0 increased fatty acid incorporation into TAG and glycerol 3-phosphate synthesis from glucose without affecting glyceroneogenesis and glycerokinase expression. Corroborating in vitro findings, treatment of wild-type but not PPARα-deficient mice with 16:1n7 increased primary adipocyte basal and stimulated lipolysis and ATGL and HSL mRNA levels. In contrast to lipolysis, however, 16:1n7 treatment increased fatty acid incorporation into TAG and glycerol 3-phosphate synthesis from glucose in both wild-type and PPARα-deficient mice. In conclusion, palmitoleic acid increases adipocyte lipolysis and lipases by a mechanism that requires a functional PPARα.

scholarly journals RIPK1 activates distinct gasdermins in macrophages and neutrophils upon pathogen blockade of innate immune signalling

2021 ◽  
Author(s):  
Kaiwen W. Chen ◽  
Benjamin Demarco ◽  
Rosalie Heilig ◽  
Saray P Ramos ◽  
James P Grayczyk ◽  
...  
Keyword(s):  
Effector Proteins ◽  
Innate Immune ◽  
Target Cells ◽  
Caspase 8 ◽  
Dependent Manner ◽  
Wild Type ◽  
Mapk Signalling ◽  
Common Strategy ◽  
Deficient Mice

AbstractInjection of effector proteins to block host innate immune signalling is a common strategy used by many pathogenic organisms to establish an infection. Pathogenic Yersinia species for example inject the acetyltransferase YopJ into target cells to inhibit NF-κB and MAPK signalling. To counteract this, detection of YopJ activity in myeloid cells promotes the assembly of a RIPK1-caspase-8 death-inducing platform that confers antibacterial defence. While recent studies revealed that caspase-8 cleaves the pore-forming protein, gasdermin D (GSDMD) to trigger pyroptosis in macrophages, whether RIPK1 activates additional substrates downstream of caspase-8 to promote host defence is unclear. Here, we report that the related gasdermin family member gasdermin E (GSDME) is activated upon detection of YopJ activity in a RIPK1 kinase-dependent manner. Specifically, GSDME promotes neutrophil pyroptosis and IL-1β release, which is critical for anti-Yersinia defence. During in vivo infection, IL-1β neutralisation increases bacterial burden in wild type but not Gsdme-deficient mice. Thus, our study establishes GSDME as an important mediator that counteracts pathogen blockade of innate immune signalling.

scholarly journals 5-Lipoxygenase Negatively Regulates Th1 Response during Brucella abortus Infection in Mice

2015 ◽  
Vol 83 (3) ◽  
pp. 1210-1216 ◽  
Author(s):  
Júlia Silveira Fahel ◽  
Mariana Bueno de Souza ◽  
Marco Túlio Ribeiro Gomes ◽  
Patricia P. Corsetti ◽  
Natalia B. Carvalho ◽  
...  
Keyword(s):  
Brucella Abortus ◽  
Critical Role ◽  
Lipid Mediators ◽  
Negative Regulator ◽  
Host Responses ◽  
Interleukin 12 ◽  
Dependent Manner ◽  
Wild Type ◽  
Content Type ◽  
Deficient Mice

Brucella abortusis a Gram-negative bacterium that infects humans and cattle, causing a chronic inflammatory disease known as brucellosis. A Th1-mediated immune response plays a critical role in host control of this pathogen. Recent findings indicate contrasting roles for lipid mediators in host responses against infections. 5-Lipoxygenase (5-LO) is an enzyme required for the production of the lipid mediators leukotrienes and lipoxins. To determine the involvement of 5-LO in host responses toB. abortusinfection, we intraperitoneally infected wild-type and 5-LO-deficient mice and evaluated the progression of infection and concomitant expression of immune mediators. Here, we demonstrate thatB. abortusinduced the upregulation of 5-LO mRNA in wild-type mice. Moreover, this pathogen upregulated the production of the lipid mediators leukotriene B4and lipoxin A4in a 5-LO-dependent manner. 5-LO-deficient mice displayed lower bacterial burdens in the spleen and liver and less severe liver pathology, demonstrating an enhanced resistance to infection. Host resistance paralleled an increased expression of the proinflammatory mediators interleukin-12 (IL-12), gamma interferon (IFN-γ), and inducible nitric oxide synthase (iNOS) during the course of infection. Moreover, we demonstrated that 5-LO downregulated the expression of IL-12 in macrophages duringB. abortusinfection. Our results suggest that 5-LO has a major involvement inB. abortusinfection, by functioning as a negative regulator of the protective Th1 immune responses against this pathogen.

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