Glia Maturation Factor-Gamma Mediates Human Monocytes Migration Through Regulating β1/β2-Integrin Recycling

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 1027-1027
Author(s):  
Wulin Aerbajinai ◽  
Lunhua Liu ◽  
Chutima Kumkhaek ◽  
Kyung Chin ◽  
Griffin P. Rodgers
Keyword(s):  
Plasma Membrane ◽  
Molecular Mechanisms ◽  
Conflicts Of Interest ◽  
Inflammatory Cells ◽  
Effective Control ◽  
Glia Maturation Factor ◽  
Β2 Integrin ◽  
Maturation Factor ◽  
Early Endosomes ◽  
And Migration

Abstract Recruitment of monocytes is essential for effective control and clearance of invading pathogens by migrating to the sites of infection, but recruited monocytes also contribute to the pathogenesis of chronic inflammatory and degenerative diseases, such as rheumatoid arthritis, multiple sclerosis, atherosclerosis and cancer. Thus, understanding the mechanisms controlling monocytes migration within different environments is of paramount importance. Although it is clear that adhesion signaling via integrin receptors and the surrounding ECM play a significant role in regulating migration of monocytes to site of inflammation, the underlying cellular and molecular mechanisms responsible for these process is still not fully characterized. Defining the molecular circuits through which integrins regulate monocytes motility is therefore important for gaining a better understanding of monocytes function. Glia maturation factor gamma (GMFG), a novel ADF/cofilin superfamily protein that is predominantly expressed in inflammatory cells, has been implicated in regulating actin reorganization. We have previously demonstrated that GMFG plays a role in regulating neutrophil chemotaxis and migration. We now examine whether GMFG has similar effects on monocytes and the cellular mechanism for these effects by using small-interfering RNA to knockdown GMFG in human primary monocytes. Knockdown of endogenous GMFG results in significantly reduced (220.6 ± 9.4 to 89.0 ± 3.2, p<0.003) chemotactic migration toward SDF-1 and enhanced adhesion on fibronectin, VCAM-1 and ICAM-1 compared with control siRNA transfected cells. Flow cytometry analysis shows that knockdown of GMFG enhances the expression of β1-, β2−integrin on the cell surface compared with control cells. Confocal microscopy analysis exhibited that GMFG is colocalized with internalized β1-, β2-integrin in early endosomes in primary monocytes. However, an internalization assay shows that β1- and β2-integrin were internalized with similar kinetics during the initial uptake time points both in control or GMFG knockdown primary monocytes. These data demonstrated that internalization of β1- and β2-integrin was not impaired in GMFG knockdown cells, suggesting that GMFG regulates β integrins recycling. Antibody-based recycling assays showed that GMFG knockdown cells resulted in enhanced plasma membrane exocytosis of β1- and β2-integrin compared with control cells. Western blot analysis revealed that SDF-1 stimulated the phosphoryalation of FAK (Tyr397) is moderately (∼ 40%) increased in GMFG knockdown monocytes compared with control cells. These results suggest that impaired monocytes migrated toward SDF-1 stimulation in GMFG depletion monocytes is due to enhanced adhesion, which is caused by accelerated recycling of β1- and β2-integrin to the surface. Taken together, these results indicate that GMFG is required to maintain the proper expression levels of β1- and β2-integrin on the plasma membrane and is fundamental for integrin-mediated monocytes motility. Disclosures: No relevant conflicts of interest to declare.

Glia Maturation Factor-Gamma Regulates Macrophage Migration Through Control Recycling of alpha5beta1 Integrin in Endosome

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 3273-3273
Author(s):  
Wulin Aerbajinai ◽  
Lunhua Liu ◽  
Kyung Chin ◽  
Griffin P Rodgers
Keyword(s):  
Molecular Mechanisms ◽  
Conflicts Of Interest ◽  
Inflammatory Diseases ◽  
Leading Edge ◽  
Inflammatory Cells ◽  
Human Macrophage ◽  
Macrophage Migration ◽  
Glia Maturation Factor ◽  
Maturation Factor ◽  
Α5β1 Integrin

Abstract Abstract 3273 Macrophages play an essential role in defending against invading pathogens by migrating to the sites of infection, removing apoptotic cells, and secreting inflammatory cytokines. Macrophage migration is a critical step in the regulation of immune response and is also associated with many chronic inflammatory diseases such as rheumatoid arthritis, multiple sclerosis, atherosclerosis and cancer. Thus, understanding the mechanisms controlling macrophage migration within different environments is of paramount importance. Although it is clear that adhesion signaling via integrin receptors and the surrounding ECM play a significant role in regulating migration of macrophages to site of inflammation, the underlying cellular and molecular mechanisms responsible for these process is still not fully characterized. Defining the molecular circuits through which integrins regulate macrophage motility is therefore important for gaining a better understanding of macrophage function. Glia maturation factor gamma (GMFG), a novel ADF/cofilin superfamily protein that is predominantly expressed in inflammatory cells, has been implicated in regulating actin reorganization. We have previously demonstrated that GMFG plays a role in regulating neutrophil chemotaxis and migration. We now examine whether GMFG has similar effects on macrophage and the cellular mechanism for these effects by using small-interfering RNA technic to knockdown GMFG in human macrophage like THP-1cells. Knockdown of endogenous GMFG results in significantly reduced chemotactic migration toward fMLP and enhanced adhesion on fibronectin compared with control siRNA transfected cells. Flow cytometry analysis shows that GMFG-knockdown cells expresses significant amount of α5β1 integrin on the surface compared with control cells. Confocal microscopy analysis exhibited that GMFG was distributed throughout the cytosol and colocalized with the multiple endocytic compartment such as early endosome marker EEA1, Rab5, Rab4 and Rab11. Importantly, we found that most of the α5β1 integrins accumulated in clusters at the rear of the GMFG-knockdown cells, along with colocalization with endosome marker EEA1, rather than localization toward the leading edge in response to fMLP stimulation in control cells. These results suggest that impaired efficient α5β1 integrin recycling cause to increased adhesion, which is responsible for reduced macrophage migration on fibronectin in GMFG depletion macrophages. Accordingly, GMFG is required for proper trafficking of endosomal α5β1 integrin to the plasma membrane and is fundamental for integrin-mediated macrophage motility. Disclosures: No relevant conflicts of interest to declare.

P-Selectin-β2-Integrin Cross-Talk: A Molecular Mechanism For Polymorphonuclear Leukocyte Recruitment At The Site Of Vascular Damage

1999 ◽  
Vol 82 (08) ◽  
pp. 787-793 ◽  
Author(s):  
Virgilio Evangelista ◽  
Giovanni de Gaetano ◽  
Chiara Cerletti
Keyword(s):  
Cross Talk ◽  
Molecular Mechanisms ◽  
Vascular Damage ◽  
Tissue Integrity ◽  
Β2 Integrin ◽  
Leukocyte Accumulation ◽  
Platelet Thrombus ◽  
And Migration ◽  
The One ◽  
Pmn Leukocyte

IntroductionPlatelets activated at the site of vascular damage play a pivotal role in polymorphonuclear (PMN) leukocyte accumulation in a growing thrombus2,3 and may substitute endothelial cells in the recruitment and migration of leukocytes through damaged vessel wall.4 Leukocytes, accumulated in a platelet thrombus, can contribute to further platelet activation5 and to increased fibrin deposition.6 These events, on the one hand, may contribute to the maintenance of vascular and tissue integrity. They may, however, play a pathogenic role in inflammatory and thrombotic disease, providing some biological plausibility to the epidemiological evidence of significant association between leukocyte count and the incidence of coronary heart disease.7,8 We shall focus our attention on the molecular mechanisms involved in the recruitment of PMN leukocytes on activated platelets as it occurs at the site of vascular damage, with particular attention to P-selectin- β2-integrin cross-talk.

scholarly journals A novel mass assay to quantify the bioactive lipid PtdIns3P in various biological samples

2012 ◽  
Vol 447 (1) ◽  
pp. 17-23 ◽  
Author(s):  
Gaëtan Chicanne ◽  
Sonia Severin ◽  
Cécile Boscheron ◽  
Anne-Dominique Terrisse ◽  
Marie-Pierre Gratacap ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Liquid Chromatography ◽  
Biological Samples ◽  
Mammalian Cells ◽  
Molecular Mechanisms ◽  
Human Platelets ◽  
Bhk Cells ◽  
Early Endosomes ◽  
Important Player ◽  
Mass Level

PtdIns3P is recognized as an important player in the control of the endocytotic pathway and in autophagy. Recent data also suggest that PtdIns3P contributes to molecular mechanisms taking place at the plasma membrane and at the midbody during cytokinesis. This lipid is present in low amounts in mammalian cells and remains difficult to quantify either by traditional techniques based on radiolabelling followed by HPLC to separate the different phosphatidylinositol monophosphates, or by high-sensitive liquid chromatography coupled to MS, which is still under development. In the present study, we describe a mass assay to quantify this lipid from various biological samples using the recombinant PtdIns3P 5-kinase, PIKfyve. Using this assay, we show an increase in the mass level of PtdIns3P in mouse and human platelets following stimulation, loss of this lipid in Vps34-deficient yeasts and its relative enrichment in early endosomes isolated from BHK cells.

scholarly journals Phospholipase D Activity Regulates Integrin-mediated Cell Spreading and Migration by Inducing GTP-Rac Translocation to the Plasma Membrane

2008 ◽  
Vol 19 (7) ◽  
pp. 3111-3123 ◽  
Author(s):  
Young Chan Chae ◽  
Jung Hwan Kim ◽  
Kyung Lock Kim ◽  
Hyun Wook Kim ◽  
Hye Young Lee ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Phospholipase D ◽  
Molecular Mechanisms ◽  
Direct Interaction ◽  
Cell Spreading ◽  
Small Gtpase ◽  
General Mechanism ◽  
Downstream Target ◽  
P21 Activated Kinase ◽  
And Migration

Small GTPase Rac is a crucial regulator of actin cytoskeletal rearrangement, and it plays an important role in cell spreading, migration, mitogenesis, phagocytosis, superoxide generation, and axonal growth. It is generally accepted that Rac activity is regulated by the guanosine triphosphate (GTP)/guanosine diphosphate (GDP) cycle. But, it is suggested that in addition to Rac-GTP loading, membrane localization is required for the initiation of downstream effector signaling. However, the molecular mechanisms that control the targeting of GTP-Rac to the plasma membrane remain largely unknown. Here, we have uncovered a signaling pathway linking phospholipase D (PLD) to the localized functions of Rac1. We show that PLD product phosphatidic acid (PA) acts as a membrane anchor of Rac1. The C-terminal polybasic motif of Rac1 is responsible for direct interaction with PA, and Rac1 mutated in this region is incapable of translocating to the plasma membrane and of activating downstream target p21-activated kinase upon integrin activation. Finally, we show that PA induces dissociation of Rho-guanine nucleotide dissociation inhibitor from Rac1 and that PA-mediated Rac1 localization is important for integrin-mediated lamellipodia formation, cell spreading, and migration. These results provide a novel molecular mechanism for the GTP-Rac1 localization through the elevating PLD activity, and they suggest a general mechanism for diverse cellular functions that is required localized Rac activation.

scholarly journals Competitive binding of Rab21 and p120RasGAP to integrins regulates receptor traffic and migration

2011 ◽  
Vol 194 (2) ◽  
pp. 291-306 ◽  
Author(s):  
Anja Mai ◽  
Stefan Veltel ◽  
Teijo Pellinen ◽  
Artur Padzik ◽  
Eleanor Coffey ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Cell Motility ◽  
Molecular Mechanisms ◽  
Regulatory Mechanism ◽  
Competitive Binding ◽  
Small Gtpase ◽  
Rab Gtpases ◽  
Endocytic Machinery ◽  
And Migration ◽  
Α Subunits

Integrin trafficking from and to the plasma membrane controls many aspects of cell behavior including cell motility, invasion, and cytokinesis. Recruitment of integrin cargo to the endocytic machinery is regulated by the small GTPase Rab21, but the detailed molecular mechanisms underlying integrin cargo recruitment are yet unknown. Here we identify an important role for p120RasGAP (RASA1) in the recycling of endocytosed α/β1-integrin heterodimers to the plasma membrane. Silencing of p120RasGAP attenuated integrin recycling and augmented cell motility. Mechanistically, p120RasGAP interacted with the cytoplasmic domain of integrin α-subunits via its GAP domain and competed with Rab21 for binding to endocytosed integrins. This in turn facilitated exit of the integrin from Rab21- and EEA1-positive endosomes to drive recycling. Our results assign an unexpected role for p120RasGAP in the regulation of integrin traffic in cancer cells and reveal a new concept of competitive binding of Rab GTPases and GAP proteins to receptors as a regulatory mechanism in trafficking.

Arresting inflammation: contributions of plasma membrane and endosomal signalling to neuropeptide-driven inflammatory disease

2013 ◽  
Vol 41 (1) ◽  
pp. 137-143 ◽  
Author(s):  
Fiore Cattaruzza ◽  
Daniel P. Poole ◽  
Nigel W. Bunnett
Keyword(s):  
Plasma Membrane ◽  
Cell Surface ◽  
Inflammatory Cells ◽  
Receptor Interaction ◽  
Receptor Recycling ◽  
Selective Targeting ◽  
Model Cell ◽  
And Migration ◽  
Inflammatory Signalling ◽  
G Protein Coupled

GPCR (G-protein-coupled receptor) signalling at the plasma membrane is under tight control. In the case of neuropeptides such as SP (substance P), plasma membrane signalling is regulated by cell-surface endopeptidases (e.g. neprilysin) that degrade extracellular neuropeptides, and receptor interaction with β-arrestins, which uncouple receptors from heterotrimeric G-proteins and mediate receptor endocytosis. By recruiting GPCRs, kinases and phosphatases to endocytosed GPCRs, β-arrestins assemble signalosomes that can mediate a second wave of signalling by internalized receptors. Endosomal peptidases, such as ECE-1 (endothelin-converting enzyme-1), can degrade SP in acidified endosomes, which destabilizes signalosomes and allows receptors, freed from β-arrestins, to recycle and resensitize. By disassembling signalosomes, ECE-1 terminates β-arrestin-mediated endosomal signalling. These mechanisms have been studied in model cell systems, and the relative importance of plasma membrane and endosomal signalling to complex pathophysiological processes, such as inflammation, pain and proliferation, is unclear. However, deletion or inhibition of metalloendopeptidases that control neuropeptide signalling at the plasma membrane and in endosomes has marked effects on inflammation. Neprilysin deletion exacerbates inflammation because of diminished degradation of pro-inflammatory SP. Conversely, inhibition of ECE-1 attenuates inflammation by preventing receptor recycling/resensitization, which is required for sustained pro-inflammatory signals from the plasma membrane. β-Arrestin deletion also affects inflammation because of the involvement of β-arrestins in pro-inflammatory signalling and migration of inflammatory cells. Knowledge of GPCR signalling in specific subcellular locations provides insights into pathophysiological processes, and can provide new opportunities for therapy. Selective targeting of β-arrestin-mediated endosomal signalling or of mechanisms of receptor recycling/resensitization may offer more effective and selective treatments than global targeting of cell-surface signalling.

Wnt/beta-catenin and PI3K/Akt/mTOR Signaling Pathways in Glioblastoma: Two Main Targets for Drug Design: A Review

2020 ◽  
Vol 26 (15) ◽  
pp. 1729-1741 ◽  
Author(s):  
Seyed H. Shahcheraghi ◽  
Venant Tchokonte-Nana ◽  
Marzieh Lotfi ◽  
Malihe Lotfi ◽  
Ahmad Ghorbani ◽  
...  
Keyword(s):  
Signaling Pathways ◽  
Molecular Mechanisms ◽  
Cellular Proliferation ◽  
Chemotherapy Resistance ◽  
Wnt Signaling Pathway ◽  
Therapeutic Interventions ◽  
Beta Catenin ◽  
Clinical Prognosis ◽  
Invasion And Migration ◽  
And Migration

: Glioblastoma (GBM) is the most common and malignant astrocytic glioma, accounting for about 90% of all brain tumors with poor prognosis. Despite recent advances in understanding molecular mechanisms of oncogenesis and the improved neuroimaging technologies, surgery, and adjuvant treatments, the clinical prognosis of patients with GBM remains persistently unfavorable. The signaling pathways and the regulation of growth factors of glioblastoma cells are very abnormal. The various signaling pathways have been suggested to be involved in cellular proliferation, invasion, and glioma metastasis. The Wnt signaling pathway with its pleiotropic functions in neurogenesis and stem cell proliferation is implicated in various human cancers, including glioma. In addition, the PI3K/Akt/mTOR pathway is closely related to growth, metabolism, survival, angiogenesis, autophagy, and chemotherapy resistance of GBM. Understanding the mechanisms of GBM’s invasion, represented by invasion and migration, is an important tool in designing effective therapeutic interventions. This review will investigate two main signaling pathways in GBM: PI3K/Akt/mTOR and Wnt/beta-catenin signaling pathways.

Effects and Mechanisms of Anlotinib and Dihydroartemisinin Combination Therapy in Ameliorating Malignant Biological Behavior of Gastric Cancer Cells

2020 ◽  
Vol 21 ◽  
Author(s):  
Qiong Luo ◽  
Suyun Zhang ◽  
Donghuan Zhang ◽  
Rui Feng ◽  
Nan Li ◽  
...  
Keyword(s):  
Gastric Cancer ◽  
Cancer Cells ◽  
Molecular Mechanisms ◽  
Chorioallantoic Membrane ◽  
Cell Counting ◽  
Biological Behavior ◽  
Gastric Cancer Cells ◽  
Invasion And Migration ◽  
Apoptosis Related Protein ◽  
And Migration

Background: Gastric cancer(GC) is currently one of the major malignancies that threatens human lives and health. Anlotinib is a novel small-molecule that inhibits angiogenesis to exert anti-tumor effects. However, the function in gastric cancer is incompletely understood. Objective: The aim of the present study was to investigate the anti-tumor effects and molecular mechanisms of anlotinib combined with dihydroartemisinin (DHA) in SGC7901 gastric cancer cells. Method: Different concentrations of anlotinib and DHA were used to treat SGC7901 gastric cancer cells, after which cell proliferation was measured. Drug interactions of anlotinib and DHA were analyzed by the Chou-Talalay method with CompuSyn software. proliferation, apoptosis, invasion, migration, and angiogenesis were measured using the cell counting kit-8 (CCK8) assay, flow cytometry, Transwell invasion assays, scratch assays, and chicken chorioallantoic membrane (CAM) assays. proliferation-associated protein (Ki67), apoptosis-related protein (Bcl-2), and vascular endothelial growth factor A (VEGF-A) were quantified by Western bloting. Results: The combination of 2.5 μmol/L of anlotinib and 5 of μmol/L DHA was highly synergistic in inhibiting cell growth, significantly increased the apoptosis rate and suppressed obviously the invasion and migration capability and angiogenesis of gastric cancer cells. In addition, the expression levels of Ki67, Bcl-2, and VEGF-A, as well as angiogenesis, were significantly decreased in the Combination of drugs compared with in control and either drug alone. Conclusion: The combination of anlotinib and DHA showed synergistic antitumor activity, suggesting their potential in treating patients with gastric cancer.

scholarly journals Revising Endosomal Trafficking under Insulin Receptor Activation

2021 ◽  
Vol 22 (13) ◽  
pp. 6978
Author(s):  
Maria J. Iraburu ◽  
Tommy Garner ◽  
Cristina Montiel-Duarte
Keyword(s):  
Plasma Membrane ◽  
Tyrosine Kinase ◽  
Insulin Receptor ◽  
Molecular Mechanisms ◽  
Receptor Activation ◽  
Small Gtpases ◽  
Early Endosome ◽  
Tyrosine Kinase Receptors ◽  
Endosomal Trafficking ◽  
Cell Functions

The endocytosis of ligand-bound receptors and their eventual recycling to the plasma membrane (PM) are processes that have an influence on signalling activity and therefore on many cell functions, including migration and proliferation. Like other tyrosine kinase receptors (TKR), the insulin receptor (INSR) has been shown to be endocytosed by clathrin-dependent and -independent mechanisms. Once at the early endosome (EE), the sorting of the receptor, either to the late endosome (LE) for degradation or back to the PM through slow or fast recycling pathways, will determine the intensity and duration of insulin effects. Both the endocytic and the endosomic pathways are regulated by many proteins, the Arf and Rab families of small GTPases being some of the most relevant. Here, we argue for a specific role for the slow recycling route, whilst we review the main molecular mechanisms involved in INSR endocytosis, sorting and recycling, as well as their possible role in cell functions.

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