scholarly journals Reversal of β-Amyloid-Induced Microglial Toxicity In Vitro by Activation of Fpr2/3

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Edward S. Wickstead ◽  
Husnain A. Karim ◽  
Roberta E. Manuel ◽  
Christopher S. Biggs ◽  
Stephen J. Getting ◽  
...  
Keyword(s):  
Microglial Activation ◽  
Inflammatory Marker ◽  
Subsequent Treatment ◽  
Pentose Phosphate ◽  
Formyl Peptide Receptor ◽  
Metabolic Phenotype ◽  
Ros Production ◽  
Bv2 Cells ◽  
Formyl Peptide

Microglial inflammatory activity is thought to be a major contributor to the pathology of neurodegenerative conditions such as Alzheimer’s disease (AD), and strategies to restrain their behaviour are under active investigation. Classically, anti-inflammatory approaches are aimed at suppressing proinflammatory mediator production, but exploitation of inflammatory resolution, the endogenous process whereby an inflammatory reaction is terminated, has not been fully investigated as a therapeutic approach in AD. In this study, we sought to provide proof-of-principle that the major proresolving actor, formyl peptide receptor 2, Fpr2, could be targeted to reverse microglial activation induced by the AD-associated proinflammatory stimulus, oligomeric β-amyloid (oAβ). The immortalised murine microglial cell line BV2 was employed as a model system to investigate the proresolving effects of the Fpr2 ligand QC1 upon oAβ-induced inflammatory, oxidative, and metabolic behaviour. Cytotoxic behaviour of BV2 cells was assessed through the use of cocultures with retinoic acid-differentiated human SH-SY5Y cells. Stimulation of BV2 cells with oAβ at 100 nM did not induce classical inflammatory marker production but did stimulate production of reactive oxygen species (ROS), an effect that could be reversed by subsequent treatment with the Fpr2 ligand QC1. Further investigation revealed that oAβ-induced ROS production was associated with NADPH oxidase activation and a shift in BV2 cell metabolic phenotype, activating the pentose phosphate pathway and NADPH production, changes that were again reversed by QC1 treatment. Microglial oAβ-stimulated ROS production was sufficient to induce apoptosis of bystander SH-SY5Y cells, an effect that could be prevented by QC1 treatment. In this study, we provide proof-of-concept data that indicate exploitation of the proresolving receptor Fpr2 can reverse damaging oAβ-induced microglial activation. Future strategies that are aimed at restraining neuroinflammation in conditions such as AD should examine proresolving actors as a mechanism to harness the brain’s endogenous healing pathways and limit neuroinflammatory damage.

scholarly journals Reversal of β-amyloid induced microglial toxicity in vitro by activation of Fpr2/3

2020 ◽  
Author(s):  
Edward S. Wickstead ◽  
Husnain A. Karim ◽  
Roberta E. Manuel ◽  
Christopher Biggs ◽  
Stephen J. Getting ◽  
...  
Keyword(s):  
Microglial Activation ◽  
Inflammatory Marker ◽  
Subsequent Treatment ◽  
Pentose Phosphate ◽  
Formyl Peptide Receptor ◽  
Metabolic Phenotype ◽  
Ros Production ◽  
Bv2 Cells ◽  
Β Amyloid

AbstractBackground and PurposeMicroglial inflammatory activity is thought to be a major contributor to the pathology of neurodegenerative conditions such as Alzheimer’s disease (AD), and strategies to restrain their behaviour are under active investigation. Classically, anti-inflammatory approaches aim to suppress pro-inflammatory mediator production, but exploitation of inflammatory resolution, the endogenous process whereby an inflammatory reaction is terminated, has not been fully investigated as a therapeutic approach in AD. In this study, we sought to provide proof-of-principal that the major pro-resolving actor, formyl peptide receptor 2, Fpr2, could be targeted to reverse microglial activation induced by the AD-associated pro-inflammatory stimulus, oligomeric β-amyloid (oAβ).Experimental ApproachThe immortalised murine microglial cell line BV2 was employed as a model system to investigate the pro-resolving effects of the Fpr2 ligand QC1 upon oAβ-induced inflammatory, oxidative and metabolic behaviour. Cytotoxic behaviour of BV2 cells was assessed through use of co-cultures with retinoic acid-differentiated human SH-SY5Y cells.Key ResultsStimulation of BV2 cells with oAβ at 100nM did not induce classical inflammatory marker production but did stimulate production of reactive oxygen species (ROS), an effect that could be reversed by subsequent treatment with the Fpr2 ligand QC1. Further investigation revealed that oAβ-induced ROS production was associated with NADPH oxidase activation and a shift in BV2 cell metabolic phenotype, activating the pentose phosphate pathway and NADPH production, changes that were again reversed by QC1 treatment. Microglial oAβ-stimulated ROS production was sufficient to induce apoptosis of bystander SH-SY5Y cells, an effect that could be prevented by QC1 treatment.Conclusion and ImplicationsIn this study, we provide proof-of-concept data that indicate exploitation of the pro-resolving receptor Fpr2 can reverse damaging oAβ-induced microglial activation. Future strategies aiming to restrain neuroinflammation in conditions such as AD should examine pro-resolving actors as a mechanism to harness the brain’s endogenous healing pathways and limit neuroinflammatory damage.

scholarly journals Salmonella typhimurium attachment to human intestinal epithelial monolayers: transcellular signalling to subepithelial neutrophils.

1993 ◽  
Vol 123 (4) ◽  
pp. 895-907 ◽  
Author(s):  
B A McCormick ◽  
S P Colgan ◽  
C Delp-Archer ◽  
S I Miller ◽  
J L Madara
Keyword(s):  
Epithelial Cells ◽  
Salmonella Typhimurium ◽  
Apical Membrane ◽  
Coli Strain ◽  
Formyl Peptide Receptor ◽  
Human Neutrophils ◽  
Classical Pathway ◽  
Intestinal Epithelial ◽  
Formyl Peptide

In human intestinal disease induced by Salmonella typhimurium, transepithelial migration of neutrophils (PMN) rapidly follows attachment of the bacteria to the epithelial apical membrane. In this report, we model those interactions in vitro, using polarized monolayers of the human intestinal epithelial cell, T84, isolated human PMN, and S. typhimurium. We show that Salmonella attachment to T84 cell apical membranes did not alter monolayer integrity as assessed by transepithelial resistance and measurements of ion transport. However, when human neutrophils were subsequently placed on the basolateral surface of monolayers apically colonized by Salmonella, physiologically directed transepithelial PMN migration ensued. In contrast, attachment of a non-pathogenic Escherichia coli strain to the apical membrane of epithelial cells at comparable densities failed to stimulate a directed PMN transepithelial migration. Use of the n-formyl-peptide receptor antagonist N-t-BOC-1-methionyl-1-leucyl-1- phenylalanine (tBOC-MLP) indicated that the Salmonella-induced PMN transepithelial migration response was not attributable to the classical pathway by which bacteria induce directed migration of PMN. Moreover, the PMN transmigration response required Salmonella adhesion to the epithelial apical membrane and subsequent reciprocal protein synthesis in both bacteria and epithelial cells. Among the events stimulated by this interaction was the epithelial synthesis and polarized release of the potent PMN chemotactic peptide interleukin-8 (IL-8). However, IL-8 neutralization, transfer, and induction experiments indicated that this cytokine was not responsible for the elicited PMN transmigration. These data indicate that a novel transcellular pathway exists in which subepithelial PMN respond to lumenal pathogens across a functionally intact epithelium. Based on the known unique characteristics of the intestinal mucosa, we speculate that IL-8 may act in concert with an as yet unidentified transcellular chemotactic factor(s) (TCF) which directs PMN migration across the intestinal epithelium.

scholarly journals Effects of Formyl Peptide Receptor Agonists Ac9-12 and WKYMV in In Vivo and In Vitro Acute Inflammatory Experimental Models

Cells ◽  
2022 ◽  
Vol 11 (2) ◽  
pp. 228
Author(s):  
Izabella Lice ◽  
José Marcos Sanches ◽  
Rebeca D. Correia-Silva ◽  
Mab P. Corrêa ◽  
Marcelo Y. Icimoto ◽  
...  
Keyword(s):  
Therapeutic Potential ◽  
Biological Effects ◽  
Experimental Models ◽  
Formyl Peptide Receptor ◽  
Saline Control ◽  
Acute Peritonitis ◽  
Formyl Peptide ◽  
Leukocyte Influx

Formyl peptide receptors (Fprs) are a G-protein-coupled receptor family mainly expressed on leukocytes. The activation of Fpr1 and Fpr2 triggers a cascade of signaling events, leading to leukocyte migration, cytokine release, and increased phagocytosis. In this study, we evaluate the effects of the Fpr1 and Fpr2 agonists Ac9-12 and WKYMV, respectively, in carrageenan-induced acute peritonitis and LPS-stimulated macrophages. Peritonitis was induced in male C57BL/6 mice through the intraperitoneal injection of 1 mL of 3% carrageenan solution or saline (control). Pre-treatments with Ac9-12 and WKYMV reduced leukocyte influx to the peritoneal cavity, particularly neutrophils and monocytes, and the release of IL-1β. The addition of the Fpr2 antagonist WRW4 reversed only the anti-inflammatory actions of WKYMV. In vitro, the administration of Boc2 and WRW4 reversed the effects of Ac9-12 and WKYMV, respectively, in the production of IL-6 by LPS-stimulated macrophages. These biological effects of peptides were differently regulated by ERK and p38 signaling pathways. Lipidomic analysis evidenced that Ac9-12 and WKYMV altered the intracellular lipid profile of LPS-stimulated macrophages, revealing an increased concentration of several glycerophospholipids, suggesting regulation of inflammatory pathways triggered by LPS. Overall, our data indicate the therapeutic potential of Ac9-12 and WKYMV via Fpr1 or Fpr2-activation in the inflammatory response and macrophage activation.

Design and characterization of a cleavage-resistant Annexin A1 mutant to control inflammation in the microvasculature

Blood ◽  
2010 ◽  
Vol 116 (20) ◽  
pp. 4288-4296 ◽  
Author(s):  
Magali Pederzoli-Ribeil ◽  
Francesco Maione ◽  
Dianne Cooper ◽  
Adam Al-Kashi ◽  
Jesmond Dalli ◽  
...  
Keyword(s):  
Polymorphonuclear Leukocytes ◽  
Early Stage ◽  
Leukocyte Adhesion ◽  
Formyl Peptide Receptor ◽  
Annexin A1 ◽  
Formyl Peptide ◽  
Anti Inflammatory ◽  
Human Polymorphonuclear Leukocytes

Abstract Human polymorphonuclear leukocytes adhesion to endothelial cells during the early stage of inflammation leads to cell surface externalization of Annexin A1 (AnxA1), an effector of endogenous anti-inflammation. The antiadhesive properties of AnxA1 become operative to finely tune polymorphonuclear leukocytes transmigration to the site of inflammation. Membrane bound proteinase 3 (PR3) plays a key role in this microenvironment by cleaving the N terminus bioactive domain of AnxA1. In the present study, we generated a PR3-resistant human recombinant AnxA1—named superAnxA1 (SAnxA1)—and tested its in vitro and in vivo properties in comparison to the parental protein. SAnxA1 bound and activated formyl peptide receptor 2 in a similar way as the parental protein, while showing a resistance to cleavage by recombinant PR3. SAnxA1 retained anti-inflammatory activities in the murine inflamed microcirculation (leukocyte adhesion being the readout) and in skin trafficking model. When longer-lasting models of inflammation were applied, SAnxA1 displayed stronger anti-inflammatory effect over time compared with the parental protein. Together these results indicate that AnxA1 cleavage is an important process during neutrophilic inflammation and that controlling the balance between AnxA1/PR3 activities might represent a promising avenue for the discovery of novel therapeutic approaches.

scholarly journals Activation of the pro-resolving receptors Fpr2/3 attenuate lipopolysaccharide-induced inflammatory microglial activation

2020 ◽  
Author(s):  
Edward S. Wickstead ◽  
Bradley T. Elliott ◽  
Christopher Biggs ◽  
Stephen J. Getting ◽  
Simon McArthur
Keyword(s):  
Microglial Activation ◽  
Nuclear Translocation ◽  
Therapeutic Potential ◽  
Surface Expression ◽  
Subsequent Treatment ◽  
Triggered Release ◽  
Formyl Peptide ◽  
Bv2 Microglia ◽  
Species Production ◽  
Production Effects

AbstractNeuroinflammation driven primarily by microglia directly contributes to neuronal death in many neurodegenerative diseases. Classical anti-inflammatory approaches aim to suppress pro-inflammatory mediator production, but exploitation of inflammatory resolution, the active endogenous process whereby inflammation is terminated, may also be of benefit. A key driver of peripheral inflammatory resolution, formyl peptide receptors 2/3 (Fpr2/3), is expressed by microglia, but its therapeutic potential in neurodegeneration remains unclear. Here, we sought to provide a proof-of-principle that Fpr2/3 targeting could reverse inflammatory microglial activation induced by the potent bacterial inflammogen lipopolysaccharide (LPS). Stimulation of murine BV2 microglia with LPS triggered release of nitric oxide, TNFα and IL-10, upregulated surface expression of CD38 and CD40 and suppressed CD206, all of which were reduced by subsequent treatment with the Fpr2/3 ligand C43. Cellular exposure to LPS also stimulated NADPH oxidase and mitochondrial derived reactive oxygen species production, effects reversed by C43 treatment. Mechanistic studies showed C43 to act through p38 MAPK phosphorylation and reduction of LPS-induced NFκB nuclear translocation through prevention of IκBα degradation. Here, we provide proof-of-concept data indicating exploitation of the pro-resolving receptor Fpr2/3 as a promising therapeutic strategy in neuroinflammatory conditions.

scholarly journals Development, characterisation and in vitro evaluation of lanthanide-based FPR2/ALX-targeted imaging probes

2019 ◽  
Vol 48 (44) ◽  
pp. 16764-16775 ◽  
Author(s):  
Tamara Boltersdorf ◽  
Junaid Ansari ◽  
Elena Y. Senchenkova ◽  
Lijun Jiang ◽  
Andrew J. P. White ◽  
...  
Keyword(s):  
Lanthanide Complexes ◽  
Formyl Peptide Receptor ◽  
Human Neutrophils ◽  
Targeted Imaging ◽  
In Vitro Evaluation ◽  
Peptide Receptor ◽  
Imaging Probes ◽  
Formyl Peptide

Formyl Peptide Receptor (FPR)-targeted lanthanide complexes with long-lived emission in stimulated human neutrophils.

scholarly journals The pentose phosphate pathway regulates chronic neuroinflammation and dopaminergic neurodegeneration

2019 ◽  
Vol 16 (1) ◽  
Author(s):  
Dezhen Tu ◽  
Yun Gao ◽  
Ru Yang ◽  
Tian Guan ◽  
Jau-Shyong Hong ◽  
...  
Keyword(s):  
Substantia Nigra ◽  
Pentose Phosphate Pathway ◽  
Microglial Activation ◽  
Redox Homeostasis ◽  
Pentose Phosphate ◽  
Transgenic Expression ◽  
Dopaminergic Neurodegeneration ◽  
Locomotor Impairment

Abstract Background Metabolic dysfunction and neuroinflammation are increasingly implicated in Parkinson’s disease (PD). The pentose phosphate pathway (PPP, a metabolic pathway parallel to glycolysis) converts glucose-6-phosphate into pentoses and generates ribose-5-phosphate and NADPH thereby governing anabolic biosynthesis and redox homeostasis. Brains and immune cells display high activity of glucose-6-phosphate dehydrogenase (G6PD), the rate-limiting enzyme of the PPP. A postmortem study reveals dysregulation of G6PD enzyme in brains of PD patients. However, spatial and temporal changes in activity/expression of G6PD in PD remain undetermined. More importantly, it is unclear how dysfunction of G6PD and the PPP affects neuroinflammation and neurodegeneration in PD. Methods We examined expression/activity of G6PD and its association with microglial activation and dopaminergic neurodegeneration in multiple chronic PD models generated by an intranigral/intraperitoneal injection of LPS, daily subcutaneous injection of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) for 6 days, or transgenic expression of A53T α-synuclein. Primary microglia were transfected with G6PD siRNAs and treated with lipopolysaccharide (LPS) to examine effects of G6PD knockdown on microglial activation and death of co-cultured neurons. LPS alone or with G6PD inhibitor(s) was administrated to mouse substantia nigra or midbrain neuron-glia cultures. While histological and biochemical analyses were conducted to examine microglial activation and dopaminergic neurodegeneration in vitro and in vivo, rotarod behavior test was performed to evaluate locomotor impairment in mice. Results Expression and activity of G6PD were elevated in LPS-treated midbrain neuron-glia cultures (an in vitro PD model) and the substantia nigra of four in vivo PD models. Such elevation was positively associated with microglial activation and dopaminergic neurodegeneration. Furthermore, inhibition of G6PD by 6-aminonicotinamide and dehydroepiandrosterone and knockdown of microglial G6PD attenuated LPS-elicited chronic dopaminergic neurodegeneration. Mechanistically, microglia with elevated G6PD activity/expression produced excessive NADPH and provided abundant substrate to over-activated NADPH oxidase (NOX2) leading to production of excessive reactive oxygen species (ROS). Knockdown and inhibition of G6PD ameliorated LPS-triggered production of ROS and activation of NF-кB thereby dampening microglial activation. Conclusions Our findings indicated that G6PD-mediated PPP dysfunction and neuroinflammation exacerbated each other mediating chronic dopaminergic neurodegeneration and locomotor impairment. Insight into metabolic-inflammatory interface suggests that G6PD and NOX2 are potential therapeutic targets for PD.

scholarly journals Barbadin selectively modulates FPR2-mediated neutrophil functions independent of receptor endocytosis

2020 ◽  
Author(s):  
Martina Sundqvist ◽  
André Holdfeldt ◽  
Shane C. Wright ◽  
Thor C. Møller ◽  
Esther Siaw ◽  
...  
Keyword(s):  
Nadph Oxidase ◽  
Neutrophil Migration ◽  
Adaptor Protein ◽  
Formyl Peptide Receptor ◽  
Human Neutrophils ◽  
Ros Production ◽  
Receptor Endocytosis ◽  
Formyl Peptide ◽  
Clathrin Adaptor ◽  
Nadph Oxidase Activation

AbstractFormyl peptide receptor 2 (FPR2), a member of the family of G protein-coupled receptors (GPCRs), mediates neutrophil migration, a response that has been linked to β-arrestin recruitment. β-Arrestin regulates GPCR endocytosis and can also elicit non-canonical receptor signaling. To determine the poorly understood role of β-arrestin in FPR2 endocytosis and in NADPH-oxidase activation in neutrophils, Barbadin was used as a research tool in this study. Barbadin has been shown to bind the clathrin adaptor protein (AP2) and thereby prevent β- arrestin/AP2 interaction and β-arrestin-mediated GPCR endocytosis. In agreement with this, AP2/β-arrestin interaction induced by an FPR2-specific agonist was inhibited by Barbadin. Unexpectedly, however, Barbadin did not inhibit FPR2 endocytosis, indicating that a mechanism independent of β-arrestin/AP2 interaction may sustain FPR2 endocytosis. This was confirmed by the fact, that FPR2 also underwent agonist-promoted endocytosis in β-arrestin deficient cells, albeit at a diminished level as compared to wild type cells. Dissection of the Barbadin effects on FPR2-mediated neutrophil functions including NADPH-oxidase activation mediated release of reactive oxygen species (ROS) and chemotaxis reveled that Barbadin had no effect on chemotactic migration whereas the release of ROS was potentiated/primed. The effect of Barbadin on ROS production was reversible, independent of β-arrestin recruitment, and similar to that induced by latrunculin A. Taken together, our data demonstrate that endocytic uptake of FPR2 occurs independently of β-arrestin, while Barbadin selectively augments FPR2-mediated neutrophil ROS production independently of receptor endocytosis. Given that Barbadin binds to AP2 and prevents the AP2/β-arrestin interaction, our results indicate a role for AP2 in FPR2-mediated ROS release from human neutrophils.

scholarly journals N-Formylated Peptide Induces Increased Expression of Both Formyl Peptide Receptor 2 (Fpr2) and Toll-Like Receptor 9 (TLR9) in Schwannoma Cells—An In Vitro Model for Early Inflammatory Profiling of Schwann Cells

Cells ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 2661
Author(s):  
Andrea Korimová ◽  
Petr Dubový
Keyword(s):  
Schwann Cells ◽  
Chemokine Receptors ◽  
In Vitro Model ◽  
Formyl Peptide Receptor ◽  
Toll Like Receptor ◽  
Western Blots ◽  
Peptide Receptor ◽  
Formyl Peptide ◽  
Vitro Model

Following nerve injury, disintegrated axonal mitochondria distal to the injury site release mitochondrial formylated peptides and DNA that can induce activation and inflammatory profiling of Schwann cells via formyl peptide receptor 2 (Fpr2) and toll-like receptor 9 (TLR9), respectively. We studied RT4 schwannoma cells to investigate the regulation of Fpr2 and TLR9 after stimulation with fMLF as a prototypical formylated peptide. RT4 cells were treated with fMLF at various concentrations and times with and without pretreatment with inhibitors (chloroquine for activated TLR9, PBP10 for Fpr2). Western blots of Fpr2, TLR9, p-p38, p-NFκB, and IL-6 were compared in relation to inflammatory profiling of RT4 cells and chemokine receptors (CCR2, CXCR4) as potential co-receptors of Fpr2. fMLF stimulation upregulated Fpr2 in RT4 cells at low concentrations (10 nM and 100 nM) but higher concentrations were required (10 µM and 50 µM) when the cells were pretreated with an activated TLR9 inhibitor. Moreover, the higher concentrations of fMLF could modulate TLR9 and inflammatory markers. Upregulation of Fpr2 triggered by 10 nM and 100 nM fMLF coincided with higher levels of chemokine receptors (CCR2, CXCR4) and PKCβ. Treating RT4 cells with fMLF, as an in vitro model of Schwann cells, uncovered Schwann cells’ complex responses to molecular patterns of release from injured axonal mitochondria.

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