Migration Of HL-60 Cells Research Articles

Targeting Pseudomonas aeruginosa quorum sensing with sodium salicylate modulates immune responses in vitro and in vivo.

Chronic infections are a major clinical challenge in hard-to-heal wounds and implanted devices. Pseudomonas aeruginosa is a common causative pathogen that produces numerous virulence factors. Due to the increasing problem of antibiotic resistance, new alternative treatment strategies are needed. Quorum sensing (QS) is a bacterial communication system that regulates virulence and dampens inflammation, promoting bacterial survival. QS inhibition is a potent strategy to reduce bacterial virulence and alleviate the negative impact on host immune response. This study investigates how secreted factors from P. aeruginosa PAO1, cultured in the presence or absence of the QS inhibitor sodium salicylate (NaSa), influence host immune response. In vitro, THP-1 macrophages and neutrophil-like HL-60 cells were used. In vivo, discs of titanium were implanted in a subcutaneous rat model with local administration of P. aeruginosa culture supernatants. The host immune response to virulence factors contained in culture supernatants (+/-NaSa) was characterized through cell viability, migration, phagocytosis, gene expression, cytokine secretion, and histology. In vitro, P. aeruginosa supernatants from NaSa-containing cultures significantly increased THP-1 phagocytosis and HL-60 cell migration compared with untreated supernatants (-NaSa). Stimulation with NaSa-treated supernatants in vivo resulted in: (i) significantly increased immune cell infiltration and cell attachment to titanium discs; (ii) increased gene expression of IL-8, IL-10, ARG1, and iNOS, and (iii) increased GRO-α protein secretion and decreased IL-1β, IL-6, and IL-1α secretion, as compared with untreated supernatants. In conclusion, treating P. aeruginosa with NaSa reduces the production of virulence factors and modulates major immune events, such as promoting phagocytosis and cell migration, and decreasing the secretion of several pro-inflammatory cytokines.

Ameboid cell migration through regular arrays of micropillars under confinement

Migrating cells often encounter a wide variety of topographic features—including the presence of obstacles—when navigating through crowded biological environments. Unraveling the impact of topography and crowding on the dynamics of cells is key to better understand many essential physiological processes such as the immune response. We study the impact of geometrical cues on ameboid migration of HL-60 cells differentiated into neutrophils. A microfluidic device is designed to track the cells in confining geometries between two parallel plates with distance h, in which identical micropillars are arranged in regular pillar forests with pillar spacing e. We observe that the cells are temporarily captured near pillars, with a mean contact time that is independent of h and e. By decreasing the vertical confinement h, we find that the cell velocity is not affected, while the persistence reduces; thus, cells are able to preserve their velocity when highly squeezed but lose the ability to control their direction of motion. At a given h, we show that by decreasing the pillar spacing e in the weak lateral confinement regime, the mean escape time of cells from effective local traps between neighboring pillars grows. This effect, together with the increase of cell-pillar contact frequency, leads to the reduction of diffusion constant D. By disentangling the contributions of these two effects on D in numerical simulations, we verify that the impact of cell-pillar contacts on cell diffusivity is more pronounced at smaller pillar spacing.

A Research on Drug Discovery for Intracerebral Hemorrhage Focusing on Leukotriene B4 and Its Receptor

Intracerebral hemorrhage (ICH) results from blood vessels rupture in the brain, forming a blood clot in the brain parenchyma. Leakage of blood constituents causes detrimental tissue damages, ensuing long-lasting neurological deficits; however, effective therapeutic approaches are not yet developed to date. In this study, leukotriene B4 (LTB4) and its receptor leukotriene B4 receptor 1 (BLT1) are proposed as novel therapeutic targets for ICH therapy. After the onset of ICH, the LTB4 content in the brain transiently elevated. Microglia are considered as the source of LTB4 production. Thrombin, a blood constituent, activated the BV-2 microglia and increased the LTB4 secretion from the BV-2 cells. Microglia-released LTB4 promoted its own microglial activation and neutrophil-like differentiated HL-60 cell migration activity. LTB4 receptors comprised of two types: BLT1 and BLT2, with BLT1 known to be a high-affinity receptor associated with chemotaxis. BLT1 knockout mice showed decreased neutrophil invasion, attenuating sensorimotor dysfunction after ICH. Furthermore, therapeutic administration of ONO-4057, an orally active LTB4 receptor antagonist, attenuated neutrophil invasion, microglial activation, axonal fragmentation, and sensorimotor deficits induced by ICH. These results suggest that LTB4 and its receptor BLT1 can be potential promising therapeutic targets that prevent tissue damages following ICH.

Effects of Sanchinoside R1 on Growth Invasion and Migration of HL-60 Cells and Survival of AML Model Mice

To investigate the effects of sanchinoside R1 (SR1) on cell growth, invasion and migration of HL-60 cells, as well as survival of AML mice. AML mouse models were established by intravenous injection of HL-60 cells. The SR1 of 10, 25 and 50 mg/kg was intraperitoneally injected into AML models once a day for 1 week. The survival rate of mice, tumor volume and weight were measured, and protein levels of Caspase-3 and VEGF were determined by immunohistochemistry. And protein levels of p-PI3K, PI3K, p-AKT and AKT were detected by Western blot. SR1 significantly inhibited the growth of tumors (P＜0.01, r=-0.9994, -0.9952) and increased the survival rate of mice (P＜0.01). SR1 significantly increased the protein level of apoptosis-related Caspase-3(P＜0.01, r=0.9855), and decreased the protein level of migration-related protein VEGF (P＜0.01, r=-0.9848). The protein levels of p-PI3K and p-AKT were down-regulated by SR1, Thus, the relative protein levels of p-PI3K/PI3K and p-AKT/AKT were significantly decreased (P＜0.01, r=-0.9372, -0.9953). Above-mentioned effects showed a significant positive/negative correlation with the concentration of SR1. SR1 inhibits the growth, invasion and migration of tumor cells, and increas survival of mice through affecting expression of Caspase-3, VEGF, p-PI3K, and p-AKT.

Advanced glycation end-products increase lipocalin 2 expression in human oral epithelial cells.

Diabetes mellitus (DM), a risk factor of periodontal diseases, exacerbates the pathological condition of periodontitis. A major factor for DM complications is advanced glycation end-products (AGEs) that accumulate in periodontal tissues and cause inflammatory events. Lipocalin 2 (LCN2) is an antimicrobial peptide and inflammation-related factor, and LCN2 levels increase in DM. In this study, the effects of AGEs and lipopolysaccharide of Porphyromonas gingivalis (P g-LPS) on LCN2 expression in human oral epithelial cells (TR146 cells) and the role of secreted LCN2 in periodontitis with DM were investigated. TR146 cells were cultured with AGEs (AGE2) and control BSA and cell viability was estimated, or with P g-LPS. Conditioned medium and cell lysates were prepared from cultures of epithelial cells and used for Western blotting and ELISA to analyze LCN2, RAGE, IL-6, MAPK, and NF-κB. RNA was isolated from AGE-treated TR146 cells and differentiated HL-60 (D-HL-60) cells and used for quantitative real-time PCR to examine the expression of LCN2 and interleukin-6 (IL-6) mRNAs. RAGE- and LCN2-siRNAs (siRAGE, siLCN2) were transfected into epithelial cells, and AGE-induced LCN2 expression was investigated. D-HL-60 cells were co-cultured with TR146 cells that were transfected with siLCN2 and treated with AGEs, and IL-6 mRNA expression in D-HL-60 cells and cell migration was investigated. AGEs increased the expression levels of LCN2 and IL-6 in oral epithelial cells. siRAGE and a neutralizing antibody for RAGE inhibited AGE-induced LCN2 expression. AGEs stimulated the phosphorylation of ERK, p38, and NF-κB in epithelial cells, and their inhibitors suppressed AGE-induced LCN2 expression. In contrast, P g-LPS did not show a significant increase in LCN2 level in TR146 cells that expressed Toll-like receptor 2. In co-culture experiments, AGE-induced LCN2 inhibited IL-6 mRNA expression in D-HL-60 cells, and LCN2 knockdown in epithelial cells suppressed HL-60 cell migration. These results suggested that AGEs increase LCN2 expression via RAGE, MAPK, and NF-κB signaling pathways in oral epithelial cells, and secreted LCN2 may influence the pathological condition of periodontitis with DM.

Over-expression of C3AR1 Promotes HL-60 Cell Migration and Invasion

To investigate the effect of C3AR1 on migration and invasion of HL-60 cells and its mechanism. The HL-60 cells overexpresing C3AR1 was constructed, and the HL-60-C3AR1 cell line was validated by real-time PCR and Western blot. The migration and invasion assay were performed by using transwell system, the PCR Array and flow cytometry were employed to reveal the potential mechanisms. C3AR1 gene was significantly expressed in AL cell lines, especially in acute myeloid leukemia(AML cell lines). C3a and SDF-1 together promoted migration and invasion of C3AR1 over-expressed HL-60 cells. The PCR array detection found that 16 genes (including CCL2) were significantly upregulated and 4 genes were significantly down-regulated. However, the expression of CXCR4 did not significantly change after treated by C3a and SDF-1 together. Over-expression of C3AR1 shows the effects on the migration and invasion of HL-60 cells under the treatment of C3a and SDF-1 together, which may be mediated by the regulation of CCL2 and other genes related to chemotactic factors.

Mitochondrial reactive oxygen species regulate fungal protease-induced inflammatory responses.

Epidemiological studies have shown that fungal infections are a main cause of respiratory tract diseases, such as asthma, bronchopneumonia, intoxication, and invasive fungal disease. Fungi such as Aspergillus and Candida species have become increasingly important pathogens as the global climate changes. Accordingly, in this study, we evaluated the toxicological potential of Aspergillus protease in the lower respiratory tract. Exposure of Aspergillus protease to A549 cells induced upregulation of tumor necrosis factor (TNF)-α, monocyte chemoattractant protein (MCP)-1, and intercellular adhesion molecule (ICAM)-1 mRNAs and increased production of interleukin (IL)-8 and MCP-1 protein through enhanced mitochondrial reactive oxygen species (ROS) generation and activation of mitogen-activated protein kinase (MAPK) and activator protein (AP)-1. Furthermore, the mitochondrial ROS scavenger Mito-TEMPO, which inhibited MAPK and AP-1, significantly reduced MCP-1 and IL-1β mRNA expression and reduced HL-60 cell migration through the suppression of MCP-1 and IL-8 protein secretion. Thus, our results demonstrated that mitochondria were an important source of Aspergillus protease-stimulated ROS and that regulation of mitochondrial ROS modulated inflammatory responses by preventing activation of MAPK and AP-1 in A549 cells.

Orai1 and Orai2 mediate store-operated calcium entry that regulates HL60 cell migration and FAK phosphorylation

Store-operated Ca2+ entry (SOCE) is a major mechanism for the regulation of intracellular Ca2+ homeostasis and cellular function. Emerging evidence has revealed that altered expression and function of the molecular determinants of SOCE play a critical role in the development or maintenance of several cancer hallmarks, including enhanced proliferation and migration. Here we show that, in the acute myeloid leukemia cell line HL60, Orai2 is highly expressed at the transcript level, followed by the expression of Orai1. Using fluorescence Ca2+ imaging we found that Orai2 silencing significantly attenuated thapsigargin-induced SOCE, as well as knockdown of Orai1, while silencing the expression of both channels almost completely reduced SOCE, thus suggesting that SOCE in these cells is strongly dependent on Orai1 and Orai2. On the other hand, the expression of TRPC1, TRPC3 and TRPC6 is almost absent at the transcript and protein level. Bromodeoxyuridine cell proliferation assay revealed that Orai1 and Orai2 expression silencing significantly reduced HL60 cell proliferation. Furthermore, knockdown of Orai1 and Orai2 significantly attenuated the ability of HL60 to migrate in vitro as determined by transwell migration assay, probably due to the impairment of FAK tyrosine phosphorylation. These findings provide evidence for a role for Orai1 and Orai2, in SOCE and migration in the human HL60 promyeloblastic cell line. This article is part of a Special Issue entitled: ECS Meeting edited by Claus Heizmann, Joachim Krebs and Jacques Haiech.

Soluble LR11/SorLA, a Potential Circulating Marker Indicating the G-CSF-Induced Mobilization of Hematopoietic Stem Cells, Is a Modulator of G-CSF-Mediated Migration of HL-60 Cells,

Abstract 3210 Introduction:LR11 (also called SorLA or SORL1) is a type I membrane protein from which a large extracellular part, soluble LR11 (sLR11), is released by proteolytic shedding. LR11 plays a key role in the migration of undifferentiated vascular smooth muscle cells. Circulating sLR11 levels are a marker of accumulation of immature vascular cells, with immature human CD34+CD38− hematopoietic precursor cells having been shown to express high levels of LR11 mRNA. Recently, we showed that LR11 is specifically and highly expressed on the surface of acute leukemia cells in addition to normal leukocytes (unpublished data). Granulocyte-colony stimulating factor (G-CSF) stimulates hematopoietic stem cell (HSC) mobilization from the bone marrow (BM) to peripheral circulation and is commonly accepted as inducer of HSC mobilization in patients with hematological diseases. However, the mechanism underlying G-CSF-mediated release of HSCs from BM into peripheral circulation has not been fully elucidated. This study examined serum sLR11 levels during collection of HSCs and the role of sLR11 in migration and adhesion of HL-60 cells. Materials and methods:We analyzed serum samples of 15 patients who underwent the HSC collection procedure at Chiba University Hospital between 2010 and 2011. We initially examined the effects of G-CSF on the release of sLR11 from HL-60 cells into culture supernatants by an in vitro assay. We then measured expression of LR11 on HL-60 cells by flow cytometric analysis. sLR11 levels were measured in serum or culture supernatants by an ELISA method. A migration assay was performed using HL-60 cells incubated with or without G-CSF in transwell chambers with or without HUVECs, which were pre-incubated with or without TNF-a. An adhesion assay was performed using fibronectin-coated plates with or without HUVECs pre-incubated with or without TNF-a. Results:Circulating sLR11 levels were associated with time-related changes in the number of peripheral leukocytes during collection of HSCs following G-CSF treatment. Figure 1 shows the time course of two representative cases. In Case 1, a patient with malignant lymphoma, the number of leukocytes increased concurrently with an increase in serum sLR11 levels after chemotherapy, and then both decreased simultaneously. Case 2 was a patient with POEMS syndrome who was treated with G-CSF at the time of stem cell harvest. Similar to Case 1, following administration of G-CSF, the number of leukocytes increased concurrently with the increase in serum sLR11 levels, and then both decreased simultaneously. A close relationship was observed between serum sLR11 levels and leukocyte count, with a relative ratio of 0.63. We examined sLR11 in BM plasma by ELISA and showed that sLR11 was abundant in BM and was produced by BM hematological cells. sLR11 levels were increased significantly in the media containing HL-60 cells incubated for 12 h with 100 ng/ml G-CSF compared with those containing HL-60 cells incubated without G-CSF. Surface expression of LR11 on HL-60 cells increased with G-CSF treatment compared with controls (Figure 2), but not with SDF-1 treatment. In the migration assay, sLR11 stimulated the migration of HL-60 cells in a dose-dependent manner. Stimulation of migration activity by sLR11 was observed clearly in the presence of G-CSF with or without HUVECs. In the adhesion assay, sLR11 induced attachment of HL-60 cells to fibronectin-coated plates or HUVECs. This attachment increased when HL-60 cells were incubated with G-CSF. In a trans-endothelial migration assay, sLR11 also markedly increased the migration of HL-60 cells. [Display omitted] [Display omitted] Conclusions:sLR11 is a novel chemotactic agent for HL-60 cells and induces strong enhancement of G-CSF-mediated migration and adhesion. LR11 may play a key role in G-CSF-mediated HSC mobilization by stimulating cell migration from BM into peripheral circulation. Disclosures:No relevant conflicts of interest to declare.

New Perspectives in the Studies on Endocannabinoid and Cannabis: 2-Arachidonoylglycerol as a Possible Novel Mediator of Inflammation

2-Arachidonoylglycerol is an endogenous ligand for the cannabinoid receptors. To date, two types of cannabinoid receptors (CB1 and CB2) have been identified. The CB1 receptor is assumed to be involved in the attenuation of synaptic transmission. On the other hand, the physiological roles of the CB2 receptor, which is abundantly expressed in several types of inflammatory cells and immunocompetent cells, have not yet been fully elucidated. Recently, we investigated in detail possible physiological roles of the CB2 receptor and 2-arachidonoylglycerol in inflammation. We found that 2-arachidonoylglycerol induces the activation of p42/44 and p38 mitogen-activated protein kinases and c-Jun N-terminal kinase; actin rearrangement and morphological changes; augmented production of chemokines in HL-60 cells; and the migration of HL-60 cells differentiated into macrophage-like cells, human monocytes, natural killer cells, and eosinophils. We also found that the level of 2-arachidonoylglycerol in mouse ear is markedly elevated following treatment with 12-O-tetradecanoylphorbol 13-acetate, which induces acute inflammation. Notably, the inflammation induced by 12-O-tetradecanoylphorbol 13-acetate was blocked by treatment with SR144528, a CB2-receptor antagonist. Similar results were obtained with an allergic inflammation model in mice. These results strongly suggest that 2-arachidonoylglycerol plays essential roles in the stimulation of various inflammatory reactions in vivo.

Activation of extracellular regulated kinases is required for the increase in airway epithelial permeability during leukocyte transmigration.

The goal of this study was to determine whether the extracellular regulated kinases (ERK1/2) are involved in leukocyte transmigration across airway epithelium and the associated changes in epithelial permeability. In vitro, we used formyl-methionyl-leucyl-phenylalanine (fMLP) to induce migration of HL-60 cells (a human leukocyte cell line) across sheets of polarized Calu-3 airway epithelial cells and also to induce migration of human neutrophils across primary cultures of cow tracheal epithelial cells. In both systems, leukocyte migration decreased transepithelial electrical resistance (R(te)), increased epithelial permeability to albumin (P(alb)), and increased ERK1/2 phosphorylation in epithelial cells. Leukocyte migration and the associated changes in R(te), P(alb), and ERK1/2 phosphorylation were inhibited by calphostin C, a blocker of protein kinase C (PKC), and by PD98059 (a blocker of ERK1/2). Leukocyte transmigration in rat tracheas in vivo was induced with fMLP, and was associated with increased P(alb) and phosphorylation of epithelial ERK1/2. Again, migration and the associated changes were inhibited by luminal PD98059 or calphostin C though neither agent affected rat leukocyte migration in Boyden chambers in vitro. We conclude that PKC and ERK1/2 pathways are activated in airway epithelial cells during migration of leukocytes and are important regulators of airway epithelial permeability.

2-Arachidonoylglycerol Induces the Migration of HL-60 Cells Differentiated into Macrophage-like Cells and Human Peripheral Blood Monocytes through the Cannabinoid CB2 Receptor-dependent Mechanism

2-Arachidonoylglycerol is an endogenous ligand for the cannabinoid receptors (CB1 and CB2) and has been shown to exhibit a variety of cannabimimetic activities in vitro and in vivo. Recently, we proposed that 2-arachidonoylglycerol is the true endogenous ligand for the cannabinoid receptors, and both receptors (CB1 and CB2) are primarily 2-arachidonoylglycerol receptors. The CB1 receptor is assumed to be involved in the attenuation of neurotransmission. On the other hand, the physiological roles of the CB2 receptor, which is abundantly expressed in several types of leukocytes such as macrophages, still remain unknown. In this study, we examined the effects of 2-arachidonoylglycerol on the motility of HL-60 cells differentiated into macrophage-like cells. We found that 2-arachidonoylglycerol induces the migration of differentiated HL-60 cells. The migration induced by 2-arachidonoylglycerol was blocked by treatment of the cells with either SR144528, a CB2 receptor antagonist, or pertussis toxin, suggesting that the CB2 receptor and Gi/Go are involved in the 2-arachidonoylglycerol-induced migration. Several intracellular signaling molecules such as Rho kinase and mitogen-activated protein kinases were also suggested to be involved. In contrast to 2-arachidonoylglycerol, anandamide, another endogenous cannabinoid receptor ligand, failed to induce the migration. The 2-arachidonoylglycerol-induced migration was also observed for two other types of macrophage-like cells, the U937 cells and THP-1 cells, as well as human peripheral blood monocytes. These results strongly suggest that 2-arachidonoylglycerol induces the migration of several types of leukocytes such as macrophages/monocytes through a CB2 receptor-dependent mechanism thereby stimulating inflammatory reactions and immune responses.

SDF-1–induced actin polymerization and migration in human hematopoietic progenitor cells

The capacity of hematopoietic progenitor cells (HPCs; CD34(+) cells) to respond to chemotactic stimulation is essential for their homing efficiency, e.g., during stem cell transplantation. Previous studies established that stromal cell-derived factor-1 (SDF-1) and its receptor CXCR-4 play an important role in the homing of HPCs. The aim of the present study was to analyze SDF-1-induced actin polymerization and migration of HL-60 cells and primary human CD34(+) cells. SDF-1-induced migration of CD34(+) cells from cord blood (CB) and peripheral blood (PB) across fibronectin-coated filters was measured in a Transwell assay. Actin polymerization was detected using fluorescent phalloidin and analyzed by confocal microscopy and FACS analysis. SDF-1 induced a rapid and transient increase in actin polymerization and in polarization of the actin cytoskeleton in primary CD34(+) cells and HL-60 cells. SDF-1 was found to induce significantly more actin polymerization in CB CD34(+) cells that show fast migration in vitro compared to slow migrating PB CD34(+) cells. Moreover, CB CD34(+) cells that had migrated toward SDF-1 showed an elevated and prolonged rise in F-actin upon second exposure to SDF-1 compared to nonmigrated cells, although both cell types expressed equal levels of the SDF-1 receptor CXCR-4. The relatively high migratory capacity of CB-derived human HPCs is not related to cellular polarization or high expression of the SDF-1 receptor but is largely determined by their capacity to efficiently polymerize F-actin in response to SDF-1.

P2U Agonists Induce Chemotaxis and Actin Polymerization in Human Neutrophils and Differentiated HL60 Cells

Human neutrophils or HL60 cells express P2U receptors and respond to micromolar concentrations of ATP, adenosine 5'-O-(thiotriphosphate) (ATPgammaS), or UTP with immediate increases in intracellular Ca2+ through activation of phosphoinositide phospholipase C (Cowen, D. S., Lazarus, H. M., Shurin, S. B., Stoll, S. E., and Dubyak, G. R. (1989) J. Clin. Invest. 83, 1651-1660). P2U agonists reportedly induce limited enzyme secretion and enhance the respiratory burst in response to chemotactic factors. We demonstrate here that P2U agonists are chemotactic for neutrophils or differentiated HL60 cells. Rhodamine phalloidin staining indicates that ATPgammaS treatment induces actin polymerization and shape changes similar to those seen when these cells are treated with chemotactic peptide fMet-Leu-Phe. Although undifferentiated HL60 cells fail to mount a rise in Ca2+ when challenged with fMet-Leu-Phe, they increase Ca2+ in response to P2U agonists. However, functional expression of phospholipase C-coupled receptors is not sufficient for chemotaxis since HL60 cell migration in response to these agonists or to fMet-Leu-Phe occurs only after exposure to differentiating agents such as BT2cAMP. In addition to the well known G protein-linked receptors for lipid or peptide chemotactic factors, neutrophils apparently also can utilize G protein-linked purino/pyrimidino receptors to recognize nucleotides as chemoattractants. High concentrations of ATP and UTP generated at sites of platelet aggregation and tissue injury could thus be important mediators of inflammation.