Scholars@Duke
Suzanne Barbour

Suzanne Barbour

Dean of The Graduate School and Vice Provost for Graduate Education
Graduate School
suzanne.barbour@duke.edu
2127 Campus Drive, Durham, NC 27708
2127 Campus Drive, Durham, NC 27708

Selected Publications

Alterations in β-Cell Sphingolipid Profile Associated with ER Stress and iPLA2β: Another Contributor to β-Cell Apoptosis in Type 1 Diabetes.

Journal Article Molecules · October 21, 2021 Type 1 diabetes (T1D) development, in part, is due to ER stress-induced β-cell apoptosis. Activation of the Ca2+-independent phospholipase A2 beta (iPLA2β) leads to the generation of pro-inflammatory eicosanoids, which contribute to β-cell death and T1D. E ... Full text Open Access Link to item Cite

Macrophage polarization is linked to Ca2+-independent phospholipase A2β-derived lipids and cross-cell signaling in mice.

Journal Article J Lipid Res · February 2020 Phospholipases A2 (PLA2s) catalyze hydrolysis of the sn-2 substituent from glycerophospholipids to yield a free fatty acid (i.e., arachidonic acid), which can be metabolized to pro- or anti-inflammatory eicosanoids. Macrophages modulate inflammatory respon ... Full text Link to item Cite

Analyses of Calcium-Independent Phospholipase A2beta (iPLA2β) in Biological Systems.

Chapter · 2017 The Ca2+-independent phospholipases A2 (iPLA2s) are part of a diverse family of PLA2s, manifest activity in the absence of Ca2+, are ubiquitous, and participate in a variety of biological processes. Among the iPLA2s, the cytosolic iPLA2β has received consi ... Full text Link to item Cite

Group VIA Phospholipase A2 (iPLA2β) Modulates Bcl-x 5'-Splice Site Selection and Suppresses Anti-apoptotic Bcl-x(L) in β-Cells.

Journal Article J Biol Chem · April 24, 2015 Diabetes is a consequence of reduced β-cell function and mass, due to β-cell apoptosis. Endoplasmic reticulum (ER) stress is induced during β-cell apoptosis due to various stimuli, and our work indicates that group VIA phospholipase A2β (iPLA2β) participat ... Full text Link to item Cite

Role of calcium-independent phospholipase A(2)β in human pancreatic islet β-cell apoptosis.

Journal Article Am J Physiol Endocrinol Metab · December 1, 2012 Death of β-cells due to apoptosis is an important contributor to β-cell dysfunction in both type 1 and type 2 diabetes mellitus. Previously, we described participation of the Group VIA Ca(2+)-independent phospholipase A(2) (iPLA(2)β) in apoptosis of insuli ... Full text Link to item Cite

Lysophosphatidic acid activates lipogenic pathways and de novo lipid synthesis in ovarian cancer cells.

Journal Article J Biol Chem · July 20, 2012 One of the most common molecular changes in cancer is the increased endogenous lipid synthesis, mediated primarily by overexpression and/or hyperactivity of fatty acid synthase (FAS) and acetyl-CoA carboxylase (ACC). The changes in these key lipogenic enzy ... Full text Link to item Cite

Lyn but not Fyn kinase controls IgG-mediated systemic anaphylaxis.

Journal Article J Immunol · May 1, 2012 Anaphylaxis is a rapid, life-threatening hypersensitivity reaction. Until recently, it was mainly attributed to histamine released by mast cells activated by allergen crosslinking (XL) of FcεRI-bound allergen-specific IgE. However, recent reports establish ... Full text Link to item Cite

Epoxyeicosatrienoic acids are involved in the C70 fullerene derivative-induced control of allergic asthma

Journal Article Journal of Allergy and Clinical Immunology · January 1, 2012 Background: Fullerenes are molecules being investigated for a wide range of therapeutic applications. We have shown previously that certain fullerene derivatives (FDs) inhibit mast cell (MC) function in vitro, and here we examine their in vivo therapeutic ... Full text Cite

Anti-phosphorylcholine-opsonized low-density lipoprotein promotes rapid production of proinflammatory cytokines by dendritic cells and natural killer cells.

Journal Article J Periodontal Res · December 2010 BACKGROUND AND OBJECTIVE: Epidemiological and animal studies suggest that periodontal infections increase atherosclerosis risk. Periodontitis patients have elevated levels of anti-phosphorylcholine (anti-PC) reactive not only with numerous periodontal orga ... Full text Link to item Cite

A link between endoplasmic reticulum stress-induced β-cell apoptosis and the group VIA Ca2+-independent phospholipase A2 (iPLA2β).

Journal Article Diabetes Obes Metab · October 2010 Endoplasmic reticulum (ER) stress is becoming recognized as an important contributing factor in various diseases, including diabetes mellitus. Prolonged ER stress can cause β-cell apoptosis; however, the underlying mechanism(s) that contribute to this proc ... Full text Link to item Cite

Lipoproteins and lipoprotein metabolism in periodontal disease

Journal Article Clinical Lipidology · June 1, 2010 A growing body of evidence indicates that the incidence of atherosclerosis is increased in subjects with periodontitis - a chronic infection of the oral cavity. This article summarizes the evidence that suggests periodontitis shifts the lipoprotein profile ... Full text Cite

Group VIA Ca2+-independent phospholipase A2 (iPLA2beta) and its role in beta-cell programmed cell death.

Journal Article Biochimie · June 2010 Activation of phospholipases A(2) (PLA(2)s) leads to the generation of biologically active lipid mediators that can affect numerous cellular events. The Group VIA Ca(2+)-independent PLA(2), designated iPLA(2)beta, is active in the absence of Ca(2+), activa ... Full text Link to item Cite

Spontaneous development of endoplasmic reticulum stress that can lead to diabetes mellitus is associated with higher calcium-independent phospholipase A2 expression: a role for regulation by SREBP-1.

Journal Article J Biol Chem · February 26, 2010 Our recent studies indicate that endoplasmic reticulum (ER) stress causes INS-1 cell apoptosis by a Ca(2+)-independent phospholipase A(2) (iPLA(2)beta)-mediated mechanism that promotes ceramide generation via sphingomyelin hydrolysis and subsequent activat ... Full text Link to item Cite

Calcium-independent phospholipase A2 participates in KCl-induced calcium sensitization of vascular smooth muscle.

Journal Article Cell Calcium · July 2009 In vascular smooth muscle, KCl not only elevates intracellular free Ca(2+) ([Ca(2+)](i)), myosin light chain kinase activity and tension (T), but also can inhibit myosin light chain phosphatase activity by activation of rhoA kinase (ROCK), resulting in Ca( ... Full text Link to item Cite

Group VI phospholipases A2: homeostatic phospholipases with significant potential as targets for novel therapeutics.

Journal Article Curr Drug Targets · August 2008 Group VI phospholipase A2 (PLA2) is a family of acyl hydrolases that targets the sn-2 fatty acid on the glycerophospholipid (GPL) backbone. These enzymes are grouped together based on structural homologies and catalytic activities that are independent of c ... Full text Link to item Cite

Apoptosis induces expression of sphingosine kinase 1 to release sphingosine-1-phosphate as a "come-and-get-me" signal.

Journal Article FASEB J · August 2008 Sphingosine-1-phosphate (S1P) is a bioactive lipid that regulates myriad important cellular processes, including growth, survival, cytoskeleton rearrangements, motility, and immunity. Here we report that treatment of Jurkat and U937 leukemia cells with the ... Full text Link to item Cite

Atherogenic lipoprotein parameters in patients with aggressive periodontitis.

Journal Article J Periodontal Res · December 2007 BACKGROUND AND OBJECTIVE: Certain types of chronic infection increase the plasma level of very-low-density lipoprotein, leading to formation of the particularly atherogenic low-density lipoprotein subclass, small dense low-density lipoprotein. In the prese ... Full text Link to item Cite

Inhibition of calcium-independent phospholipase A2 suppresses proliferation and tumorigenicity of ovarian carcinoma cells.

Journal Article Biochem J · September 15, 2007 PLA2 (phospholipase A2) enzymes play critical roles in membrane phospholipid homoeostasis and in generation of lysophospholipid growth factors. In the present study, we show that the activity of the cytosolic iPLA2 (calcium-independent PLA2), but not that ... Full text Link to item Cite

Differential platelet-activating factor synthesis by monocytes and polymorphonuclear leukocytes from subjects with localized aggressive periodontitis.

Journal Article J Periodontal Res · June 2007 BACKGROUND AND OBJECTIVE: Platelet-activating factor is elevated in localized aggressive periodontitis. We previously demonstrated that the elevated level of platelet-activating factor in localized aggressive periodontitis is at least partially attributabl ... Full text Link to item Cite

The immunosuppressant drug FTY720 inhibits cytosolic phospholipase A2 independently of sphingosine-1-phosphate receptors.

Journal Article Blood · February 1, 2007 FTY720 is a potent immunomodulator drug that inhibits the egress of lymphocytes from secondary lymphoid tissues and thymus. FTY720 is phosphorylated in vivo by sphingosine kinase 2 to FTY720-phosphate, which acts as a potent sphingosine-1-phosphate (S1P) r ... Full text Link to item Cite

Influence of proinflammatory cytokines on Actinobacillus actinomycetemcomitans specific IgG responses.

Journal Article J Periodontal Res · February 2006 OBJECTIVE: High levels of serum anti-Actinobacillus actinomycetemcomitans immunoglobulin G (IgG) correlate with reduced extent and severity of periodontal disease and the present study was undertaken to begin testing the hypothesis that proinflammatory cyt ... Full text Link to item Cite

Altered lipoprotein subclass distribution and PAF-AH activity in subjects with generalized aggressive periodontitis.

Journal Article J Lipid Res · December 2005 In this study, we examined whether the documented increase of plasma triglycerides in patients with generalized aggressive periodontitis (GAgP) is associated with changes in lipoprotein subclass distribution and/or LDL-associated platelet-activating factor ... Full text Link to item Cite

Dendritic-NK cell interactions in P. gingivalis-specific responses.

Journal Article J Dent Res · September 2005 Patients with localized aggressive periodontitis have type-1 cytokines in gingival crevicular fluid and high titers of IFN-gamma-dependent IgG2 reactive with P. gingivalis in gingival crevicular fluid and serum. Localized aggressive periodontitis monocytes ... Full text Link to item Cite

Cell cycle dependence of group VIA calcium-independent phospholipase A2 activity.

Journal Article J Biol Chem · December 17, 2004 Homeostasis of phosphatidylcholine (PC) is regulated by the opposing actions between CTP:phosphocholine cytidylyltransferase (CT) and the group VIA Ca(2+)-independent phospholipase A(2) (iPLA(2)). We investigated this process during the cell cycle. PC mass ... Full text Link to item Cite

Modulation of adaptive immune responses by sphingosine-1-phosphate.

Journal Article Semin Cell Dev Biol · October 2004 Sphingosine-1-phosphate (S1P) has long been recognized as a mediator of a variety of cell functions. A growing body of evidence has accumulated demonstrating its role in cell migration and as a mediator of growth factor-induced events. In recent years, it ... Full text Link to item Cite

Dendritic cells stimulated with Actinobacillus actinomycetemcomitans elicit rapid gamma interferon responses by natural killer cells.

Journal Article Infect Immun · September 2004 Human immunoglobulin G2 (IgG2) responses are gamma interferon (IFN-gamma) dependent, and monocyte-derived dendritic cells (mDCs) promote IgG2 production. DCs spontaneously emerge from monocytes in cultures prepared from localized aggressive periodontitis ( ... Full text Link to item Cite

Regulation of group VIA phospholipase A2 expression by sterol availability.

Journal Article Biochim Biophys Acta · August 30, 2004 Several lines of evidence suggest that glycerophospholipid mass is maintained through the coordinate regulation of CTP:phosphocholine cytidylyltransferase-alpha (CTalpha) and the group VIA calcium-independent phospholipase A2 (iPLA2). CTalpha expression is ... Full text Link to item Cite

Delineation of the role of platelet-activating factor in the immunoglobulin G2 antibody response.

Journal Article Clin Diagn Lab Immunol · July 2004 Localized aggressive periodontitis (LAgP) is a chronic inflammatory disease characterized by severe destruction of periodontal tissues surrounding the first molars and incisors. LAgP subjects produce large amounts of immunoglobulin G2 (IgG2) antibody again ... Full text Link to item Cite

The immunosuppressant FTY720 is phosphorylated by sphingosine kinase type 2.

Journal Article FEBS Lett · November 6, 2003 The potent immunosuppressive drug FTY720, a sphingosine analog, induces redistribution of lymphocytes from circulation to secondary lymphoid tissues. FTY720 is phosphorylated in vivo and functions as an agonist for four G-protein-coupled sphingosine-1-phos ... Full text Link to item Cite

Anti-cardiolipin antibodies in sera from patients with periodontitis.

Journal Article J Dent Res · November 2003 Antiphospholipid antibodies are commonly found in patients with systemic lupus erythematosus or the antiphospholipid syndrome, and a subset of such antibodies is associated with prothrombotic events such as stroke and with adverse pregnancy outcomes and fe ... Full text Link to item Cite

Prostaglandin E2-mediated regulation of immunoglobulin G2 via interferon gamma.

Journal Article J Periodontol · June 2003 BACKGROUND: Patients with localized aggressive periodontitis (LAgP) produce elevated levels of IgG2 both in vivo and in vitro. Responses to the periodontitis-associated pathogens Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis are dominat ... Full text Link to item Cite

Differential expression of platelet-activating factor acetylhydrolase in macrophages and monocyte-derived dendritic cells.

Journal Article J Immunol · January 1, 2003 Although macrophages (Mphi) and monocyte-derived dendritic cells (MDDC) come from a common precursor, they are distinct cell types. This report compares the two cell types with respect to the metabolism of platelet-activating factor (PAF), a biologically a ... Full text Link to item Cite

Monocyte differentiation in localized juvenile periodontitis is skewed toward the dendritic cell phenotype.

Journal Article Infect Immun · June 2002 Several lines of evidence indicate that the monocytes of subjects with localized juvenile periodontitis (LJP) are functionally distinct from cells of age- and race-matched nonperiodontitis (NP) subjects. Among the abnormalities are the propensity to secret ... Full text Link to item Cite

Phosphatidylcholine transfer protein promotes apolipoprotein A-I-mediated lipid efflux in Chinese hamster ovary cells.

Journal Article J Biol Chem · February 22, 2002 Phosphatidylcholine transfer protein (PC-TP) is a cytosolic protein of unknown function that catalyzes intermembrane transfer of phosphatidylcholines in vitro. Using stably transfected CHO cells, we explored the influence of PC-TP on apolipoprotein A-I- an ... Full text Link to item Cite

Non-redundant roles for interleukin-1 alpha and interleukin-1 beta in regulating human IgG2.

Journal Article J Periodontol · October 2001 BACKGROUND: Serum concentrations of immunoglobulin G2 (IgG2) are elevated in localized aggressive periodontitis (LAgP) patients, and secretory products of monocytes from LAgP patients enhance IgG2 responses of lymphocytes from healthy subjects. Furthermore ... Full text Link to item Cite

Naegleria fowleri amoebae express a membrane-associated calcium-independent phospholipase A(2).

Journal Article Biochim Biophys Acta · February 26, 2001 Naegleria fowleri, a free-living amoeba, is the causative agent of primary amoebic meningoencephalitis. Previous reports have demonstrated that N. fowleri expresses one or more forms of phospholipase A(2) (PLA(2)) and that a secreted form of this enzyme is ... Full text Link to item Cite

Invasion of human vascular endothelial cells by Actinobacillus actinomycetemcomitans via the receptor for platelet-activating factor.

Journal Article Infection and immunity · September 2000 Strains of the periodontal pathogen Actinobacillus actinomycetemcomitans are variable with respect to display of phosphorylcholine (PC)-bearing antigens. We have examined strains of A. actinomycetemcomitans with and without PC to assess their ability to in ... Full text Cite

Regulation of immunoglobulin G2 production by prostaglandin E(2) and platelet-activating factor.

Journal Article Infect Immun · March 2000 Patients with localized juvenile periodontitis (LJP) have elevated levels of immunoglobulin G2 (IgG2) in their sera. This is also observed in vitro when peripheral blood leukocytes from LJP patients are stimulated with pokeweed mitogen. In previous studies ... Full text Link to item Cite

Regulation of phosphatidylcholine homeostasis by calcium-independent phospholipase A2.

Journal Article Biochim Biophys Acta · July 9, 1999 Phosphatidylcholine (PtdCho) is the most abundant phospholipid in mammalian cell membranes and is essential for cell viability. The levels of this lipid must be tightly controlled to maintain homeostasis. Therefore, changes in the rate of PtdCho synthesis ... Full text Link to item Cite

Induction of phosphatidylcholine synthesis in cho cells by sPLA2

Journal Article FASEB Journal · December 1, 1998 Phosphatidylcholine (PC) is the major phospholipid in mammalian cell mem branes and is tightly regulated to maintain homeostasis. Treatments that cause PC degradation stimulate PC synthesis and vice versa. Previous work in Chi nese hamster ovary ( CHO ) re ... Cite

Mature macrophage cell lines exhibit variable responses to LPS.

Journal Article Mol Immunol · October 1998 Bacterial lipopolysaccharide (LPS) is a potent activator of cells of the macrophage/monocyte lineage. Two mature macrophage cell lines, P388D1 and RAW264.7, exhibit very different biological responses to LPS. Although RAW264.7 cells release arachidonic aci ... Full text Link to item Cite

Coordinate regulation of stress- and mitogen-activated protein kinases in the apoptotic actions of ceramide and sphingosine.

Journal Article Mol Pharmacol · December 1997 We characterized participation of the stress-activated protein kinase (SAPK) cascade in the lethal actions of the cytotoxic lipid messengers ceramide and sphingosine in U937 human monoblastic leukemia cells. Acute exposure of U937 cells to either lipid res ... Full text Link to item Cite

Arachidonic acid mobilization in P388D1 macrophages is controlled by two distinct Ca(2+)-dependent phospholipase A2 enzymes.

Journal Article Proc Natl Acad Sci U S A · November 8, 1994 Macrophage-like P388D1 cells mobilize arachidonic acid (AA) and produce prostaglandin E2 upon stimulation with bacterial lipopolysaccharide and platelet-activating factor. We have now demonstrated that AA mobilization in these cells is composed of two dist ... Full text Link to item Cite

Antisense inhibition of group II phospholipase A2 expression blocks the production of prostaglandin E2 by P388D1 cells.

Journal Article J Biol Chem · October 15, 1993 Macrophage-like P388D1 cells release [3H]arachidonic acid and produce prostaglandin E2 (PGE2) upon stimulation with bacterial lipopolysaccharide (LPS) and platelet-activating factor (PAF). To determine whether group II phospholipase A2 (PLA2) is involved i ... Link to item Cite

Cell-specific constraints to the lateral diffusion of a membrane glycoprotein.

Journal Article J Cell Physiol · March 1992 We have previously shown that the lateral diffusion, D, of the class I Major Histocompatibility Complex (MHC) glycoprotein H-2Ld is constrained by its glycosylation, when expressed in mouse L-cells. Removal of one or more of the 3 N-linked oligosaccharides ... Full text Link to item Cite

Glycolipid depletion using a ceramide analogue (PDMP) alters growth, adhesion, and membrane lipid organization in human A431 cells.

Journal Article J Cell Physiol · March 1992 Glycolipids were depleted from the membranes of human A431 cells using 1-phenyl-2-decanoylamino-3-morpholino-1-propanol (PDMP), an inhibitor of glucosylceramide synthetase. After 6 days of culture in the presence of 5 microM D-threo-PDMP, glycolipid conten ... Full text Link to item Cite

Role of complement C9 and calcium in the generation of arachidonic acid and its metabolites from rat polymorphonuclear leukocytes.

Journal Article Mol Immunol · December 1987 We have previously shown that antibody-sensitized mouse peritoneal macrophages release arachidonic acid (C20:4) and its oxygenated derivatives when treated with complement, and that the major part of the release depended on the terminal complement complexe ... Full text Link to item Cite