PRAM-1 Is Required for Optimal Integrin-Dependent Neutrophil Function

Clemens, Regina A.; Newbrough, Sally; Chung, Elaine Y.; Gheith, Shereen M F; Singer, Andrew L.; Koretzky, Gary A.; Peterson, Erik

doi:10.1128/mcb.24.24.10923-10932.2004

Cited by 26 publications

(31 citation statements)

References 64 publications

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“…Thus, oxidative burst induced by proinflammatory signals is amplified by orders of magnitude in adherent neutrophils (9,11,12). Consistent with this observation, mice with genetic deletions of molecules involved in integrin signaling exhibit profound defects in adhesion-dependent oxidative burst (13)(14)(15)(16)(17)(18)(19)(20)(21). Notably, integrin signaling in neutrophils was recently shown to proceed via a canonical immunoreceptor tyrosine-based activation motif-mediated (ITAM-mediated) pathway in which Src family kinases phosphorylate ITAMs in DAP12 and FcRγ chains, thus creating docking sites for Syk family kinases (13), which phosphorylate numerous downstream targets leading to the assembly of a signaling complex composed of SLP-76, Vav, and phospholipase C-γ (PLC-γ) (22).…”

Section: Introductionsupporting

confidence: 49%

Neutrophil-mediated oxidative burst and host defense are controlled by a Vav-PLCγ2 signaling axis in mice

Graham¹,

Robertson²,

Bautista³

et al. 2007

J. Clin. Invest.

116

115

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Oxidative burst, a critical antimicrobial mechanism of neutrophils, involves the rapid generation and release of reactive oxygen intermediates (ROIs) by the NADPH oxidase complex. Genetic mutations in an NADPH oxidase subunit, gp91 (also referred to as NOX2), are associated with chronic granulomatous disease (CGD), which is characterized by recurrent and life-threatening microbial infections. To combat such infections, ROIs are produced by neutrophils after stimulation by integrin-dependent adhesion to the ECM in conjunction with stimulation from inflammatory mediators, or microbial components containing pathogenassociated molecular patterns. In this report, we provide genetic evidence that both the Vav family of Rho GTPase guanine nucleotide exchange factors (GEFs) and phospholipase C-γ2 (PLC-γ2) are critical mediators of adhesion-dependent ROI production by neutrophils in mice. We also demonstrated that Vav was critically required for neutrophil-dependent host defense against systemic infection by Staphylococcus aureus and Pseudomonas aeruginosa, 2 common pathogens associated with fatal cases of hospital-acquired pneumonia. We identified a molecular pathway in which Vav GEFs linked integrin-mediated signaling with PLC-γ2 activation, release of intracellular Ca 2+ cations, and generation of diacylglycerol to control assembly of the NADPH oxidase complex and ROI production by neutrophils. Taken together, our data indicate that integrin-dependent signals generated during neutrophil adhesion contribute to the activation of NADPH oxidase by a variety of distinct effector pathways, all of which require Vav.

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Section: Introductionsupporting

confidence: 49%

Neutrophil-mediated oxidative burst and host defense are controlled by a Vav-PLCγ2 signaling axis in mice

Graham¹,

Robertson²,

Bautista³

et al. 2007

J. Clin. Invest.

116

115

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“…For in vitro studies, mouse neutrophils were isolated from bone marrow (BM) as described (28,29) with the following modifications: BM cells were layered on a 62.5% Percoll column, centrifuged at 1600 rpm (GS-6KR; Beckman Coulter) for 30 min at room temperature, and neutrophils in the pellet were resuspended in calcium-and magnesium-free PBS. The samples were subjected to hypotonic lysis of RBC with cold water.…”

Section: Neutrophil Isolationmentioning

confidence: 99%

Vav Proteins in Neutrophils Are Required for FcγR-Mediated Signaling to Rac GTPases and Nicotinamide Adenine Dinucleotide Phosphate Oxidase Component p40(phox)

Utomo

Culleré

Glogauer

et al. 2006

The Journal of Immunology

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Phagocytes generate reactive oxygen species, the regulation of which is important in eliminating ingested microbes while limiting tissue damage. Clustering of FcγRs results in the activation of Vav proteins, Rho/Rac guanine nucleotide exchange factors, and results in robust superoxide generation through the NADPH oxidase. In this study, studies in neutrophils isolated from mice deficient in Vav or Rac isoforms demonstrate a critical role for Vav3 in Rac2-dependent activation of the NADPH oxidase following FcγR clustering. However, studies in cytokine-primed cells revealed a strict requirement for Vav1 and Vav3 and Rac1 and Rac2 in the FcγR-mediated oxidative burst. In comparison, Vav was not essential for PMA or G protein-coupled receptor-mediated superoxide generation. The FcγR-mediated oxidative burst defect in Vav-deficient cells was linked to aberrant Rac activation as well as Rac- and actin-polymerization-independent, but PI3K-dependent, phosphorylation of the NADPH oxidase component p40(phox). In macrophages, Vav regulation of Rac GTPases was required specifically in FcγR-mediated activation of the oxidative burst, but not in phagocytosis. Thus, Vav proteins specifically couple FcγR signaling to NADPH oxidase function through a Rac-dependent as well as an unexpected Rac-independent signal that is proximal to NADPH oxidase activation and does not require actin polymerization.

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“…Bone marrow-derived neutrophils were isolated as previously described (22). Briefly, bone marrow was flushed from the femur and tibia of mice with HBSS Prep (5.4 mM KCl, 0.3 mM Na 2 HPO 4 , 0.8 mM KH 2 PO 4 , 4.2 mM NaHCO 3 , 137 mM NaCl, 5.6 mM dextrose, 20 mM HEPES, 0.5% FBS).…”

Section: Cell Isolationmentioning

confidence: 99%

Phospholipase Cβ Is Critical for T Cell Chemotaxis

Bach¹,

Chen²,

Kerr³

et al. 2007

The Journal of Immunology

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Chemokines acting through G protein-coupled receptors play an essential role in the immune response. PI3K and phospholipase C (PLC) are distinct signaling molecules that have been proposed in the regulation of chemokine-mediated cell migration. Studies with knockout mice have demonstrated a critical role for PI3K in Gαi protein-coupled receptor-mediated neutrophil and lymphocyte chemotaxis. Although PLCβ is not essential for the chemotactic response of neutrophils, its role in lymphocyte migration has not been clearly defined. We compared the chemotactic response of peripheral T cells derived from wild-type mice with mice containing loss-of-function mutations in both of the two predominant lymphocyte PLCβ isoforms (PLCβ2 and PLCβ3), and demonstrate that loss of PLCβ2 and PLCβ3 significantly impaired T cell migration. Because second messengers generated by PLCβ lead to a rise in intracellular calcium and activation of PKC, we analyzed which of these responses was critical for the PLCβ-mediated chemotaxis. Intracellular calcium chelation decreased the chemotactic response of wild-type lymphocytes, but pharmacologic inhibition of several PKC isoforms had no effect. Furthermore, calcium efflux induced by stromal cell-derived factor-1α was undetectable in PLCβ2β3-null lymphocytes, suggesting that the migration defect is due to the impaired ability to increase intracellular calcium. This study demonstrates that, in contrast to neutrophils, phospholipid second messengers generated by PLCβ play a critical role in T lymphocyte chemotaxis.

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PRAM-1 Is Required for Optimal Integrin-Dependent Neutrophil Function

Cited by 26 publications

References 64 publications

Neutrophil-mediated oxidative burst and host defense are controlled by a Vav-PLCγ2 signaling axis in mice

Neutrophil-mediated oxidative burst and host defense are controlled by a Vav-PLCγ2 signaling axis in mice

Vav Proteins in Neutrophils Are Required for FcγR-Mediated Signaling to Rac GTPases and Nicotinamide Adenine Dinucleotide Phosphate Oxidase Component p40(phox)

Phospholipase Cβ Is Critical for T Cell Chemotaxis

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