scholarly journals Knockout of Formyl Peptide Receptor-1 Attenuates Cigarette Smoke–Induced Airway Inflammation in Mice

2021 ◽  
Vol 12 ◽  
Author(s):  
Lijuan Gao ◽  
Ni Zeng ◽  
Zhicheng Yuan ◽  
Tao Wang ◽  
Lei Chen ◽  
...  
Keyword(s):  
Western Blot ◽  
Airway Inflammation ◽  
Inflammatory Cytokines ◽  
Bioinformatics Analysis ◽  
Formyl Peptide Receptor ◽  
Wild Type ◽  
Peptide Receptor ◽  
Formyl Peptide ◽  
Gene Study ◽  
Pro Inflammatory Cytokines

Objective: The formyl peptide receptor-1 (FPR-1) has been reported to be implicated in the regulation of inflammatory disorders, while its role in cigarette smoke (CS)–induced airway inflammation has not been fully explained. In this study, we investigated the role of FPR-1 in CS-induced airway inflammation and the possible mechanism through gene knockout (KO) technology and transcriptional study.Methods: FPR-1 KO or wild-type C57BL/6 mice were exposed to mainstream CS to establish an airway inflammation model. Cell counts and pro-inflammatory cytokines were measured in bronchoalveolar lavage fluid (BALF). Lung tissues were collected for histological examination, polymerase chain reaction, Western blot, transcriptomic gene study, and related bioinformatics analysis.Results: CS exposure induced significant histological inflammatory changes, increased neutrophils, and pro-inflammatory cytokines in the BALF of wild-type mice, which were all attenuated by KO of FPR-1. The transcriptomic gene study showed a total of 198 up-regulated genes and 282 down-regulated genes in mouse lungs. Bioinformatics analysis including Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) suggested these differentiated expressed genes were significantly related to the immune, chemotaxis responses, and cross-talked with a complicated network of signaling pathways including NF-κB. Western blot validated that KO of FPR-1 inhibited CS-induced NF-κB activation.Conclusion: Knockout of FPR-1 significantly ameliorates CS-induced airway inflammation in mice, possibly via its related immune-chemotaxis responses and inhibition of NF-κB activation.

scholarly journals A single amino acid substitution (N297A) in the conserved NPXXY sequence of the human N-formyl peptide receptor results in inhibition of desensitization and endocytosis, and a dose-dependent shift in p42/44 mitogen-activated protein kinase activation and chemotaxis

2000 ◽  
Vol 352 (2) ◽  
pp. 399-407 ◽  
Author(s):  
Jeannie M. GRIPENTROG ◽  
Algirdas J. JESAITIS ◽  
Heini M. MIETTINEN
Keyword(s):  
Protein Kinase ◽  
Transmembrane Domain ◽  
Mitogen Activated Protein Kinase ◽  
Formyl Peptide Receptor ◽  
Wild Type ◽  
Peptide Receptor ◽  
Formyl Peptide ◽  
Mitogen Activated Protein ◽  
Dose Dependent Increase ◽  
Dose Dependent

The formyl peptide receptor (FPR) is a G-protein-coupled receptor (GPCR) that mediates chemotaxis and stimulates the mitogen-activated protein kinase (MAPK)/extracellular-signal-regulated kinase pathway. We have examined the functional effects of substitutions of a conserved aspartic acid residue in the second transmembrane domain (D71A) and of residues in the conserved NPXXY motif in the seventh transmembrane domain (N297A and Y301A). These mutated receptors, expressed in Chinese hamster ovary (CHO) cells, bind ligand with affinities similar to wild-type FPR, but the D71A mutant is uncoupled from G-protein [Miettinen, Mills, Gripentrog, Dratz, Granger and Jesaitis (1997) J. Immunol 159, 4045–4054]. In the present study, we show that both the D71A and N297A mutations resulted in defective endocytosis. The N297A substitution also prevented desensitization, as determined by intracellular calcium mobilization by sequential stimulation with ligand. In chemotaxis assays, the N297A mutation resulted in cell migration towards gradients of up to 100nM N-formyl-methionyl-leucyl-phenylalanine (fMLF), whereas cells expressing the wild-type FPR and the Y301A mutant were no longer chemotactically responsive at 10–100nM fMLF. Maximal activation of p42/44 MAPK occurred in CHO cells expressing wild-type FPR at 10nM–100nM fMLF, whereas cells expressing the N297A mutant showed a dose-dependent increase in the amount of phosphorylated p42/44 MAPK up to 1–10µM fMLF. Since the MAPK kinase inhibitor PD98059 blocked fMLF-induced chemotaxis, our results suggest that the dose-dependent increase in p42/44 MAPK activation may correlate with the increased chemotactic migration of N297A transfectants at 10nM–100nM fMLF.

scholarly journals The N-Formyl Peptide Receptor 2 (FPR2) Agonist MR-39 Improves Ex Vivo and In Vivo Amyloid Beta (1–42)-Induced Neuroinflammation in Mouse Models of Alzheimer’s Disease

2021 ◽  
Author(s):  
Ewa Trojan ◽  
Kinga Tylek ◽  
Nicole Schröder ◽  
Iris Kahl ◽  
Lars-Ove Brandenburg ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Inflammatory Cytokines ◽  
Ex Vivo ◽  
Neuronal Loss ◽  
Formyl Peptide Receptor ◽  
Peptide Receptor ◽  
Formyl Peptide ◽  
Anti Inflammatory

Abstract The major histopathological hallmarks of Alzheimer’s disease (AD) include β-amyloid (Aβ) plaques, neurofibrillary tangles, and neuronal loss. Aβ 1–42 (Aβ1-42) has been shown to induce neurotoxicity and secretion of proinflammatory mediators that potentiate neurotoxicity. Proinflammatory and neurotoxic activities of Aβ1-42 were shown to be mediated by interactions with several cell surface receptors, including the chemotactic G protein-coupled N-formyl peptide receptor 2 (FPR2). The present study investigated the impact of a new FPR2 agonist, MR-39, on the neuroinflammatory response in ex vivo and in vivo models of AD. To address this question, organotypic hippocampal cultures from wild-type (WT) and FPR2-deficient mice (knockout, KO, FPR2−/−) were treated with fibrillary Aβ1-42, and the effect of the new FPR2 agonist MR-39 on the release of pro- and anti-inflammatory cytokines was assessed. Similarly, APP/PS1 double-transgenic AD mice were treated for 20 weeks with MR-39, and immunohistological staining was performed to assess neuronal loss, gliosis, and Aβ load in the hippocampus and cortex. The data indicated that MR-39 was able to reduce the Aβ1-42-induced release of proinflammatory cytokines and to improve the release of anti-inflammatory cytokines in mouse hippocampal organotypic cultures. The observed effect was apparently related to the inhibition of the MyD88/TRAF6/NFкB signaling pathway and a decrease in NLRP3 inflammasome activation. Administration of MR-39 to APP/PS1 mice improved neuronal survival and decreased microglial cell density and plaque load.These results suggest that FPR2 may be a promising target for alleviating the inflammatory process associated with AD and that MR-39 may be a useful therapeutic agent for AD.

scholarly journals Punicalagin Prevents Inflammation in LPS-Induced RAW264.7 Macrophages by Inhibiting FoxO3a/Autophagy Signaling Pathway

Nutrients ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 2794 ◽  
Author(s):  
Cao ◽  
Chen ◽  
Ren ◽  
Zhang ◽  
Tan ◽  
...  
Keyword(s):  
Western Blot ◽  
Signaling Pathway ◽  
Inflammatory Cytokines ◽  
Blot Analysis ◽  
Western Blot Analysis ◽  
Inflammatory Responses ◽  
Raw264.7 Macrophages ◽  
Tnf Α ◽  
Autophagy Inhibition ◽  
Pro Inflammatory Cytokines

Punicalagin, a hydrolysable tannin of pomegranate juice, exhibits multiple biological effects, including inhibiting production of pro-inflammatory cytokines in macrophages. Autophagy, an intracellular self-digestion process, has been recently shown to regulate inflammatory responses. In this study, we investigated the anti-inflammatory potential of punicalagin in lipopolysaccharide (LPS) induced RAW264.7 macrophages and uncovered the underlying mechanisms. Punicalagin significantly attenuated, in a concentration-dependent manner, LPS-induced release of NO and decreased pro-inflammatory cytokines TNF-α and IL-6 release at the highest concentration. We found that punicalagin inhibited NF-κB and MAPK activation in LPS-induced RAW264.7 macrophages. Western blot analysis revealed that punicalagin pre-treatment enhanced LC3II, p62 expression, and decreased Beclin1 expression in LPS-induced macrophages. MDC assays were used to determine the autophagic process and the results worked in concert with Western blot analysis. In addition, our observations indicated that LPS-induced releases of NO, TNF-α, and IL-6 were attenuated by treatment with autophagy inhibitor chloroquine, suggesting that autophagy inhibition participated in anti-inflammatory effect. We also found that punicalagin downregulated FoxO3a expression, resulting in autophagy inhibition. Overall these results suggested that punicalagin played an important role in the attenuation of LPS-induced inflammatory responses in RAW264.7 macrophages and that the mechanisms involved downregulation of the FoxO3a/autophagy signaling pathway.

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