PTEN functions to 'prioritize' chemotactic cues and prevent 'distraction' in migrating neutrophils

Heit, Bryan; Robbins, Stephen M.; Downey, Charlene M.; Guan, Zhiwen; Colarusso, Pina; Miller, B. Joan; Jirik, Frank R.; Kubes, Paul

doi:10.1038/ni.1623

Cited by 238 publications

(232 citation statements)

References 38 publications

Supporting

Mentioning

222

Contrasting

Unclassified

Order By: Relevance

“…The co-existence of these redundant pathways allows cells greater flexibility to respond to different environmental circumstances, such as gradients of high or low steepness. In mammalian cells, it is also reported that PLA plays a role in neutrophil chemotaxis to fMLP, but not to CXCL8 (41). We show here that the SFK pathway functions in parallel to PI3K in determining the directional cell movement in response to a CXCL8 gradient.…”

Section: Discussionmentioning

confidence: 52%

Parallel Phosphatidylinositol 3-Kinase (PI3K)-dependent and Src-dependent Pathways Lead to CXCL8-mediated Rac2 Activation and Chemotaxis

Sai

Raman

Liu

et al. 2008

Journal of Biological Chemistry

View full text Add to dashboard Cite

The requirement for phosphatidylinositol 3-kinase (PI3K) in the establishment of cell polarity and motility in a number of cell types has recently come into question. In this study, we demonstrate that inhibition of PI3K by wortmannin in neutrophil-like differentiated HL60 cells expressing CXCR2 resulted in reduced cell motility but normal chemotaxis in response to a gradient of CXCL8. However, wortmannin inhibition of PI3K did impair the ability of cells to re-orient their polarity and respond quickly to a change in the direction of the CXCL8 gradient. We hypothesized that Src-regulated ELMO-Dock2-Rac2 activation mediates chemotaxis in the absence of PI3K activity. Inhibition of Src with the small molecule inhibitor, PP2, or inhibition of Dock2 by shRNA knockdown confirmed the functional role of Src and Dock2 in regulating chemotaxis when PI3K was inhibited. Moreover, neutrophils isolated from bone marrow of hck ؊/؊ fgr ؊/؊ lyn ؊/؊ mice exhibited much more severe inhibition of chemotaxis when PI3K was blocked with wortmannin as compared with neutrophils isolated from bone marrow of wild-type mice. Thus, PI3K and Src-ELMO-Dock2 pathways work in parallel to activate Rac2 and modulate chemotaxis in response to a CXCL8 gradient in neutrophils.Chemotaxis is the process by which cells migrate toward a chemical gradient. It has been reported that phosphatidylinositol 3-kinases (PI3K) 2 and their product, phosphatidylinositol 3,4,5-trisphosphate (PIP3), play an important role in sensing and polarizing the cell toward a chemoattractant gradient(1-4). PI3K␥, the dominant class I PI3K in neutrophils, catalyzes the 3Ј-phosphorylation of phosphatidylinositol 4,5-bisphosphate (PIP2) to generate PIP3. In PI3K␥ knockout mice, recruitment of neutrophils to sites of inflammation was significantly reduced, though not completely inhibited. Additionally, in vitro chemotaxis assays showed incomplete inhibition of chemotaxis for neutrophils derived from these mice (5-7). Based on these data, it has been hypothesized that a PI3K-independent pathway exists in neutrophils that allows these cells to move toward a gradient of chemokine. Src family kinases (SFK) are a group of tyrosine kinases that play fundamental roles in mediating cell proliferation, survival, and focal adhesion regulation in response to a variety of environmental stimuli. In certain G protein-coupled receptor-mediated signal transduction pathways, SFK can bind and be activated by G␣ i and G␣ s subunits of the heterotrimeric G-protein (8). This PI3K-independent signal transduction pathway activated directly by heterotrimeric G proteins may lead to a different cascade of signal activation.Members of the Rho family of small GTPases are essential for regulation of cell cytoskeleton reorganization during motility and thus have great impact on cell morphology (polarized versus non-polarized). Activation of Rac has been shown to be required for extension of pseudopodia at the leading edge of moving cells. Rac2, as a hematopoietic-specific member of Rac, plays critical roles i...

show abstract

Section: Discussionmentioning

confidence: 52%

Parallel Phosphatidylinositol 3-Kinase (PI3K)-dependent and Src-dependent Pathways Lead to CXCL8-mediated Rac2 Activation and Chemotaxis

Sai

Raman

Liu

et al. 2008

Journal of Biological Chemistry

View full text Add to dashboard Cite

show abstract

“…Neutrophils prioritize between different chemoattractant cues, favoring p38-controlled migration toward bacterial end targets over PI3K-controlled migration toward endogenous chemoattractants (42). Priorization is regulated by the phosphatase and tensin homolog (PTEN) (43), which inhibits chemoattractant-derived PI3K signaling, allowing unidirectional migration to an end-target chemoattractant. It is possible that GRP and IL-8 are viewed by neutrophils as equivalent chemoattractants, and the blockage of either receptor in the presence of the other's agonist inhibits the PI3K pathway, inhibiting migration toward the other molecule.…”

Section: Discussionmentioning

confidence: 99%

Gastrin-releasing peptide receptor (GRPR) mediates chemotaxis in neutrophils

Czepielewski

Porto

Rizzo

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

Neutrophil migration to inflamed sites is crucial for both the initiation of inflammation and resolution of infection, yet these cells are involved in perpetuation of different chronic inflammatory diseases. Gastrin-releasing peptide (GRP) is a neuropeptide that acts through G protein coupled receptors (GPCRs) involved in signal transmission in both central and peripheral nervous systems. Its receptor, gastrin-releasing peptide receptor (GRPR), is expressed by various cell types, and it is overexpressed in cancer cells. RC-3095 is a selective GRPR antagonist, recently found to have antiinflammatory properties in arthritis and sepsis models. Here we demonstrate that i.p. injection of GRP attracts neutrophils in 4 h, and attraction is blocked by RC-3095. Macrophage depletion or neutralization of TNF abrogates GRP-induced neutrophil recruitment to the peritoneum. In vitro, GRP-induced neutrophil migration was dependent on PLC-β2, PI3K, ERK, p38 and independent of Gαi protein, and neutrophil migration toward synovial fluid of arthritis patients was inhibited by treatment with RC-3095. We propose that GRPR is an alternative chemotactic receptor that may play a role in the pathogenesis of inflammatory disorders.

show abstract

“…The role of PTEN in chemotaxis has been somewhat controversial, with some studies suggesting a role for PTEN in directionality or migration and others finding PTEN to be dispensable for chemotaxis. [39][40][41] These discrepancies likely reflect differences in experimental setup, such as in vitro versus in vivo studies, differences in chemoattractant gradients, and the activation state of cells. In addition, the time frame of observation is important.…”

Section: Discussionmentioning

confidence: 99%

Rac regulates PtdInsP3 signaling and the chemotactic compass through a redox-mediated feedback loop

Kuiper

Sun

Magalhães

et al. 2011

Blood

View full text Add to dashboard Cite

IntroductionNeutrophils are important mediators of the innate immune system and are rapidly recruited from the circulation to sites of infection to eliminate pathogenic threats. Key to this recruitment is the release of chemoattractants by infected host tissue or pathogens, which subsequently form a chemical gradient that attracts neutrophils to the appropriate sites. 1 In response to a chemotactic gradient, neutrophils polarize and form a leading edge pointing toward the chemoattractant source and a posterior structure called the uropod. Actin polymerization within the leading edge drives up-gradient protrusion, whereas myosin activity in the uropod detaches the rear of the cell. The proper coordination of these polarized events is essential for directional migration and depends on the asymmetrical distribution of specific molecular determinants. A hallmark of neutrophil polarization is the asymmetrical accumulation of the phospholipid phosphatidylinositol(3,4,5)-trisphosphate [PtdIns(3,4,5)P 3 ] in the leading edge. 2,3 The formation of PtdIns(3,4,5)P 3 is catalyzed by PI3Ks and is counteracted by the activity of the lipid phosphatases phosphatase and tensin homolog (PTEN) and SH2-containing inositol phosphatase (SHIP), which generate the lipid products PtdIns(4,5)P 2 and PtdIns(3,4)P 2 , respectively. 4,5 Several studies have suggested that the establishment of a robust PtdIns(3,4,5)P 3 levels requires a positive feedback loop, and this is corroborated by the observation that the introduction of exogenous PtdIns(3,4,5)P 3 induces further accumulation of endogenous PtdIns(3,4,5)P 3 in a Rho GTPase-dependent fashion. 6,7 Rac and actin polymerization were both shown to be required for the establishment of PtdIns(3,4,5)P 3 polarization via a feedback loop mechanism. 8,9 However, the exact mechanism remains elusive. Because neutrophils produce reactive oxygen species (ROS) within the leading edge during chemotaxis, 10,11 and the activity of the lipid phosphatase PTEN is markedly reduced by ROS, 12,13 we hypothesized that local ROS production in neutrophils could regulate PtdIns(3,4,5)P 3 levels through redox regulation of PTEN. We indeed identified PTEN to be a major target of chemoattractantinduced ROS formation and demonstrate that its enzymatic activity decreases accordingly. Decreased PTEN activity led to an increase of PtdIns(3,4,5)P 3 , which could be reversed by ROS scavengers or genetic ablation of NADPH-oxidase 2 (NOX2). Consistent with this finding, reduction of ROS inhibited directional migration of neutrophils toward N-formyl-L-methionyl-L-leucyl-L-phenylalanine (fMLP), uncapping of actin filaments, and Rac activity. Although Rac GTPases are important downstream effectors of PtdIns(3,4,5)P 3 , they are also crucial for ROS production. Rescue experiments with small GTPase Rac effector mutants revealed that Rac facilitates PtdIns(3,4,5)P 3 accumulation and that this effect depends on its ability to activate NADPH-oxidase. Methods Abs and reagentsRabbit polyclonal Ab against phosphorylated AKT (Thr308; #2...

show abstract

PTEN functions to 'prioritize' chemotactic cues and prevent 'distraction' in migrating neutrophils

Cited by 238 publications

References 38 publications

Parallel Phosphatidylinositol 3-Kinase (PI3K)-dependent and Src-dependent Pathways Lead to CXCL8-mediated Rac2 Activation and Chemotaxis

Parallel Phosphatidylinositol 3-Kinase (PI3K)-dependent and Src-dependent Pathways Lead to CXCL8-mediated Rac2 Activation and Chemotaxis

Gastrin-releasing peptide receptor (GRPR) mediates chemotaxis in neutrophils

Rac regulates PtdInsP3 signaling and the chemotactic compass through a redox-mediated feedback loop

Contact Info

Product

Resources

About