Granulocyte-macrophage colony-stimulating factor (GM-CSF) promotes phosphorylation and an increase in the activity of cytosolic phospholipase A2 in human neutrophils

Nahas, Nabeel; Waterman, Waltraut H.; Sha'afi, R.I.

doi:10.1042/bj3130503

Cited by 46 publications

(28 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Presence of type IV cPLA 2 has been observed in distinct subcellular compartments, including the cytosol, plasma and nuclear membranes, as well as the endoplasmic reticulum and Golgi apparatus [35][36][37]; as such, sub-groups of type IV cPLA 2 (s) could be differentially sensitive to inhibition. Along these lines, we conducted experiments designed to compare sensitivity of type IV cPLA 2 (s) implicated in the generation of LTB 4 and of PGE 2 .…”

Section: Resultsmentioning

confidence: 99%

Characterization of prostaglandin E2 generation through the cyclooxygenase (COX)-2 pathway in human neutrophils

St-Onge

Flamand

Biarc

et al. 2007

Biochimica et Biophysica Acta (BBA) - Molecular and Cell Biolog

View full text Add to dashboard Cite

In the present study, we characterized the generation of prostaglandin (PG)E 2 in human neutrophils. We found that the Ca 2+ -dependent type IV cytosolic phospholipase A 2 (cPLA 2 ) was pivotally involved in the COX-2-mediated generation of PGE 2 in response to a calcium ionophore, as determined by the use of selected PLA 2 inhibitors. PGE 2 biosynthesis elicited by bacterialderived peptides or by phagocytic stimuli acting on cell surface receptors also showed to be dependent on cPLA 2 activity. We then assessed metabolism of unesterified arachidonic acid (AA), and observed that PGE 2 production becomes favored over that of LTB 4 with higher AA concentrations. Withdrawal of calcium prevented the generation of PGE 2 in response to a calcium ionophore but did not affect the up-regulation of COX-2 or its capacity to convert AA, thus limiting its implication at the level of cPLA 2 activation. Of the main eicosanoids produced by neutrophils, only LTB 4 was able to up-regulate COX-2 expression. Finally, the only PGE synthase isoform found in neutrophils is microsomal PGE synthase-1; it co-localized with COX-2 and its expression appeared mainly constitutive. These results highlight key differences in regulatory processes of the 5-LO and COX pathways, and enhance our knowledge at several levels in the PGE 2 biosynthesis in neutrophils.

show abstract

Section: Resultsmentioning

confidence: 99%

Characterization of prostaglandin E2 generation through the cyclooxygenase (COX)-2 pathway in human neutrophils

St-Onge

Flamand

Biarc

et al. 2007

Biochimica et Biophysica Acta (BBA) - Molecular and Cell Biolog

View full text Add to dashboard Cite

show abstract

“…Third, it appears to be central in neutrophil responses to important physiologic stimuli such as fMLP and tumor necrosis factor (65, 76, 78 -80). Fourth, the p38 pathway may be particularly important since it can lead to the phosphorylation and activation of phospholipase A 2 (81,82). Arachidonic acid, the product of phospholipase A 2 , may in turn activate p38 (83).…”

Section: Discussionmentioning

confidence: 99%

L-Selectin Signaling of Neutrophil Adhesion and Degranulation Involves p38 Mitogen-activated Protein Kinase

Smolen¹,

Petersen²,

Koch³

et al. 2000

Journal of Biological Chemistry

135

104

View full text Add to dashboard Cite

The adhesion molecules known as selectins mediate the capture of neutrophils from the bloodstream. We have previously reported that ligation and cross-linking of L-selectin on the neutrophil surface enhances the adhesive function of ␤ 2 -integrins in a synergistic manner with chemotactic agonists. In this work, we examined degranulation and adhesion of neutrophils in response to cross-linking of L-selectin and addition of interleukin-8. Cross-linking of L-selectin induced priming of degranulation that was similar to that observed with the alkaloid cytochalasin B. Activation mediated by L-selectin of neutrophil shape change and adhesion through CD11b/CD18 were strongly blocked by Merck C, an imidazole-based inhibitor of p38 mitogen-activated protein kinase (MAPK), but not by a structurally similar non-binding regioisomer. Priming by L-selectin of the release of secondary, tertiary, and secretory, but not primary, granules was blocked by inhibition of p38 MAPK. Peak phosphorylation of p38 MAPK was observed within 1 min of cross-linking L-selectin, whereas phosphorylation of ERK1/2 was highest at 10 min. Phosphorylation of p38 MAPK, but not ERK1/2, was inhibited by Merck C. These data suggest that signal transduction as a result of clustering L-selectin utilizes p38 MAPK to effect neutrophil shape change, integrin activation, and the release of secondary, tertiary, and secretory granules.Neutrophils circulate in the vasculature in a passive state and become more adhesive upon stimulation at sites of inflammation. Margination to the vessel wall and subsequent transmigration and phagocytosis (1) requires a number of surface proteins, including the ␤ 2 -integrins and the selectins, as mediators of adherence to the endothelium (2-5). A sequence of molecular and biophysical events has been identified that facilitates neutrophil activation and increased adherence during the acute inflammatory response in vivo. Neutrophils entering post-capillary venules adjacent to inflammatory foci develop transient rolling adhesive interactions with endothelium via selectins (6). Following exposure to inflammatory cytokines such as tumor necrosis factor and interleukin-1, endothelial cells are induced to express E-selectin and P-selectin (6). Several surface glycoproteins on neutrophils, including L-selectin and P-selectin glycoprotein ligand 1, present oligosaccharide moieties that serve as counter receptors for E-selectin and P-selectin. In conjunction with neutrophil membrane L-selectin, which recognizes oligosaccharides on endothelial cells,

show abstract

“…Treatment of cells with Ca 2ϩ ionophores is known to increase AA release, presumably by facilitating its association with membrane phospholipids. Some groups have reported that in addition to translocation, ionophore treatment results in an increase in cPLA 2 phosphorylation (Hirasawa et al, 1995;Nahas et al, 1996;Qiu et al, 1998). To determine whether Ca 2ϩ affects phosphorylation, HeLa cells were treated in suspension with or without the Ca 2ϩ ionophore ionomycin.…”

Section: Discussionmentioning

confidence: 99%

“…This is an area of current controversy. Some have shown that an increase in the amount of intracellular Ca 2ϩ leads to an increase in cPLA 2 phosphorylation (Hirasawa et al, 1995;Nahas et al, 1996), whereas others conclude that the two events can occur independently (Lih-Ling et al, 1993;de Carvalho et al, 1996;Schalkwijk et al, 1996). To test how Ca 2ϩ and phosphorylation were regulated in the HeLa cell system, cells were treated under conditions outlined in Figure 6.…”

Section: Independent Regulation Of Translocation and Phosphorylation mentioning

confidence: 99%

Extracellular Calcium Regulates HeLa Cell Morphology during Adhesion to Gelatin: Role of Translocation and Phosphorylation of Cytosolic Phospholipase A₂

Crawford

Jacobson

1998

MBoC

View full text Add to dashboard Cite

Attachment of HeLa cells to gelatin induces the release of arachidonic acid (AA), which is essential for cell spreading. HeLa cells spreading in the presence of extracellular Ca 2ϩ released more AA and formed more distinctive lamellipodia and filopodia than cells spreading in the absence of Ca 2ϩ . Addition of exogenous AA to cells spreading in the absence of extracellular Ca 2ϩ restored the formation of lamellipodia and filopodia. To investigate the role of cytosolic phospholipase A 2 (cPLA 2 ) in regulating the differential release of AA and subsequent formation of lamellipodia and filopodia during HeLa cell adhesion, cPLA 2 phosphorylation and translocation from the cytosol to the membrane were evaluated. During HeLa cell attachment and spreading in the presence of Ca 2ϩ , all cPLA 2 became phosphorylated within 2 min, which is the earliest time cell attachment could be measured. In the absence of extracellular Ca 2ϩ , the time for complete cPLA 2 phosphorylation was lengthened to Ͻ4 min. Maximal translocation of cPLA 2 from cytosol to membrane during adhesion of cells to gelatin was similar in the presence or absence of extracellular Ca 2ϩ and remained membrane associated throughout the duration of cell spreading. The amount of total cellular cPLA 2 translocated to the membrane in the presence of extracellular Ca 2ϩ went from Ͻ20% for unspread cells to Ͼ95% for spread cells. In the absence of Ca 2ϩ only 55-65% of the total cPLA 2 was translocated to the membrane during cell spreading. The decrease in the amount translocated could account for the comparable decrease in the amount of AA released by cells during spreading without extracellular Ca 2ϩ . Although translocation of cPLA 2 from cytosol to membrane was Ca 2ϩ dependent, phosphorylation of cPLA 2 was attachment dependent and could occur both on the membrane and in the cytosol. To elucidate potential activators of cPLA 2 , the extracellular signal-related protein kinase 2 (ERK2) and protein kinase C (PKC) were investigated. ERK2 underwent a rapid phosphorylation upon early attachment followed by a dephosphorylation. Both rates were enhanced during cell spreading in the presence of extracellular Ca 2ϩ . Treatment of cells with the ERK kinase inhibitor PD98059 completely inhibited the attachment-dependent ERK2 phosphorylation but did not inhibit cell spreading, cPLA 2 phosphorylation, translocation, or AA release. Activation of PKC by phorbol ester (12-O-tetradecanoylphorbol-13-acetate) induced and attachment-dependent phosphorylation of both cPLA 2 and ERK2 in suspension cells. However, in cells treated with the PKC inhibitor Calphostin C before attachment, ERK2 phosphorylation was inhibited, whereas cPLA 2 translocation and phosphorylation remained unaffected. In conclusion, although cPLA 2 -mediated release of AA during HeLa cell attachment to a gelatin substrate was essential for cell spreading, neither ERK2 nor PKC appeared to be responsible for the attachment-induced cPLA 2 phosphorylation and the release of AA.

show abstract

Granulocyte-macrophage colony-stimulating factor (GM-CSF) promotes phosphorylation and an increase in the activity of cytosolic phospholipase A2 in human neutrophils

Cited by 46 publications

References 40 publications

Characterization of prostaglandin E2 generation through the cyclooxygenase (COX)-2 pathway in human neutrophils

Characterization of prostaglandin E2 generation through the cyclooxygenase (COX)-2 pathway in human neutrophils

L-Selectin Signaling of Neutrophil Adhesion and Degranulation Involves p38 Mitogen-activated Protein Kinase

Extracellular Calcium Regulates HeLa Cell Morphology during Adhesion to Gelatin: Role of Translocation and Phosphorylation of Cytosolic Phospholipase A₂

Contact Info

Product

Resources

About

Granulocyte-macrophage colony-stimulating factor (GM-CSF) promotes phosphorylation and an increase in the activity of cytosolic phospholipase A2 in human neutrophils

Cited by 46 publications

References 40 publications

Characterization of prostaglandin E2 generation through the cyclooxygenase (COX)-2 pathway in human neutrophils

Characterization of prostaglandin E2 generation through the cyclooxygenase (COX)-2 pathway in human neutrophils

L-Selectin Signaling of Neutrophil Adhesion and Degranulation Involves p38 Mitogen-activated Protein Kinase

Extracellular Calcium Regulates HeLa Cell Morphology during Adhesion to Gelatin: Role of Translocation and Phosphorylation of Cytosolic Phospholipase A2

Contact Info

Product

Resources

About

Extracellular Calcium Regulates HeLa Cell Morphology during Adhesion to Gelatin: Role of Translocation and Phosphorylation of Cytosolic Phospholipase A₂