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Protein kinase B (AKT) mediates phospholipase D activation via ERK1/2 and promotes respiratory burst parameters in formylpeptide-stimulated neutrophil-like HL-60 cells.

ABSTRACT: Phospholipase D (PLD), a major source of lipid second messengers (phosphatidic acid, diglycerides) in many cell types, is tightly regulated by protein kinases, but only a few of them have been identified. We show here that protein kinase B (AKT) is a novel major signaling effector of PLD activity induced by the formylpeptide f-Met-Leu-Phe (fMLP) in human neutrophil-like HL-60 cells (dHL-60 cells). AKT inhibition with the selective antagonist AKTib1/2 almost completely prevented fMLP-mediated activity of PLD, its upstream effector ERK1/2, but not p38 MAPK. Immunoprecipitation studies show that phosphorylated AKT, ERK, and PLD2 form a complex induced by fMLP, which can be prevented by AKTib1/2. In cell-free systems, AKT1 stimulated PLD activity via activation of ERK. AKT1 actually phosphorylated ERK2 as a substrate (K(m) 1 ?m). Blocking AKT activation with AKTib1/2 also prevented fMLP- but not phorbol 12-myristate 13-acetate-mediated NADPH oxidase activation (respiratory burst, RB) of dHL-60 cells. Impaired RB was associated with defective membrane translocation of NADPH oxidase components p67(phox) and p47(phox), ERK, AKT1, AKT2, but not AKT3. Depletion of AKT1 or AKT2 with antisense oligonucleotides further indicates a partial contribution of both isoforms in fMLP-induced activation of ERK, PLD, and RB, with a predominant role of AKT1. Thus, formylpeptides induce sequential activation of AKT, ERK1/2, and PLD, which represents a novel signaling pathway. A major primarily role of this AKT signaling pathway also emerges in membrane recruitment of NOX2 components p47(phox), p67(phox), and ERK, which may contribute to assembly and activation of the RB motor system, NADPH oxidase.

SUBMITTER: Patel S

PROVIDER: S-EPMC2952207 | biostudies-literature | 2010 Oct

REPOSITORIES: biostudies-literature

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Protein kinase B (AKT) mediates phospholipase D activation via ERK1/2 and promotes respiratory burst parameters in formylpeptide-stimulated neutrophil-like HL-60 cells.

Patel Satyananda S Djerdjouri Bahia B Raoul-Des-Essarts Yannick Y Dang Pham My-Chan PM El-Benna Jamel J Périanin Axel A

The Journal of biological chemistry 20100806 42

Phospholipase D (PLD), a major source of lipid second messengers (phosphatidic acid, diglycerides) in many cell types, is tightly regulated by protein kinases, but only a few of them have been identified. We show here that protein kinase B (AKT) is a novel major signaling effector of PLD activity induced by the formylpeptide f-Met-Leu-Phe (fMLP) in human neutrophil-like HL-60 cells (dHL-60 cells). AKT inhibition with the selective antagonist AKTib1/2 almost completely prevented fMLP-mediated act ...[more]

PMID: 20693286

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Project description:Toll-like receptor 2 (TLR2) is an important sensor for innate immune cells, including neutrophils, for the recognition of pathogen infection. Lipoteichoic acid (LTA), a cell wall component of gram-positive bacteria, is a TLR2 ligand. LTA-induced TLR2 signaling pathways are well established in neutrophils. However, experimental studies regarding transcriptional regulation and the molecular mechanisms in primary human neutrophils are limited due to their short lifespan. The promyelocytic leukemia cell line, HL-60, can differentiate into a neutrophil-like phenotype following treatment with dimethyl sulfoxide. The aim of the present study was to investigate whether differentiated HL-60 (dHL-60) cells induced a similar gene expression profile upon LTA treatment as that previously determined for primary human neutrophils. After 4 or 24 h of Staphylococcus aureus LTA treatment, undifferentiated HL-60 (uHL-60) and dHL-60 cells were collected for RNA sequencing. The results demonstrated that hundreds of identical differentially expressed genes (DEGs) were observed in 1 and 10 µg/ml LTA-treated dHL-60 cells following 4 and 24 h of incubation, while almost no DEGs between LTA-treated HL-60 and dHL-60 cells were observed. Using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes analyses (KEGG), it was noted that the pathways of shared DEGs between the 1 and 10 µg/ml LTA-treated dHL-60 cells at both time points were significantly enriched in immune and inflammatory response-related pathways, such as cellular response to tumor necrosis factor, interleukin-1, interferon γ, neutrophil chemotaxis, the NF-κB signaling pathway and the Toll-like receptor signaling pathway. In addition, when comparing the effect of 1 and 10 µg/ml LTA treatment on dHL60 cells, it was found that all enriched GO and KEGG pathways were associated with the TLR signaling pathways of neutrophils. The results of the present study provided important information for the implementation of mRNA profiling in LTA-treated dHL-60 cells and may indicate the feasibility of using dHL-60 cells as a research model for TLR2 signaling in human neutrophils.

Project description:AimsNeutrophil granulocytes are the major cells involved in Chlamydia trachomatis (C. trachomatis)-mediated inflammation and histopathology. A key protein in human intracellular antichlamydial defense is the tryptophan-degrading enzyme indoleamine 2,3-dioxygenase (IDO) which limits the growth of the tryptophan auxotroph Chlamydia. Despite its importance, the role of IDO in the intracellular defense against Chlamydia in neutrophils is not well characterized.MethodsGlobal gene expression screen was used to evaluate the effect of C. trachomatis serovar D infection on the transcriptome of human neutrophil granulocytes. Tryptophan metabolite concentrations in the Chlamydia-infected and/or interferon-gamma (IFNG)-treated neutrophils were measured by ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS).ResultsOur results indicate that the C. trachomatis infection had a major impact on neutrophil gene expression, inducing 1,295 genes and repressing 1,510 genes. A bioinformatics analysis revealed that important factors involved in the induction of neutrophil gene expression were the interferon-related transcription factors such as IRF1-5, IRF7-9, STAT2, ICSB, and ISGF3. One of the upregulated genes was ido1, a known infection- and interferon-induced host gene. The tryptophan-degrading activity of IDO1 was not induced significantly by Chlamydia infection alone, but the addition of IFNG greatly increased its activity. Despite the significant IDO activity in IFNG-treated cells, C. trachomatis growth was not affected by IFNG. This result was in contrast to what we observed in HeLa human cervical epithelial cells, where the IFNG-mediated inhibition of C. trachomatis growth was significant and the IFNG-induced IDO activity correlated with growth inhibition.ConclusionsIDO activity was not able to inhibit chlamydial growth in human neutrophils. Whether the IDO activity was not high enough for inhibition or other chlamydial growth-promoting host mechanisms were induced in the infected and interferon-treated neutrophils needs to be further investigated.

Dataset Information

Protein kinase B (AKT) mediates phospholipase D activation via ERK1/2 and promotes respiratory burst parameters in formylpeptide-stimulated neutrophil-like HL-60 cells.

Publications

Protein kinase B (AKT) mediates phospholipase D activation via ERK1/2 and promotes respiratory burst parameters in formylpeptide-stimulated neutrophil-like HL-60 cells.

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