Human formyl peptide receptor 1 (FPR1) c.32C>T SNP is associated with decreased soluble E-selectin levels

Regulation of Inflammation and Oxidative Stress by Formyl Peptide Receptors in Cardiovascular Disease Progression

G protein-coupled receptors (GPCRs) are the most important regulators of cardiac function and are commonly targeted for medical therapeutics. Formyl-Peptide Receptors (FPRs) are members of the GPCR superfamily and play an emerging role in cardiovascular pathologies. FPRs can modulate oxidative stress through nicotinamide adenine dinucleotide phosphate (NADPH) oxidase-dependent reactive oxygen species (ROS) production whose dysregulation has been observed in different cardiovascular diseases. Therefore, many studies are focused on identifying molecular mechanisms of the regulation of ROS production. FPR1, FPR2 and FPR3 belong to the FPRs family and their stimulation triggers phosphorylation of intracellular signaling molecules and nonsignaling proteins that are required for NADPH oxidase activation. Some FPR agonists trigger inflammatory processes, while other ligands activate proresolving or anti-inflammatory pathways, depending on the nature of the ligands. In general, bacterial and mitochondrial formylated peptides activate a proinflammatory cell response through FPR1, while Annexin A1 and Lipoxin A4 are anti-inflammatory FPR2 ligands. FPR2 can also trigger a proinflammatory pathway and the switch between FPR2-mediated pro- and anti-inflammatory cell responses depends on conformational changes of the receptor upon ligand binding. Here we describe the detrimental or beneficial effects of the main FPR agonists and their potential role as new therapeutic and diagnostic targets in the progression of cardiovascular diseases.

The Role of Formyl Peptide Receptor 1 Gene Polymorphisms in Human Colorectal Cancer

Formyl peptide receptor 1 (FPR1) belongs to G protein-coupled receptors expressed mainly in phagocytic leukocytes. The gene encoding FPR1 is highly polymorphic and related to inflammation. In this study, we investigated the single nucleotide polymorphisms (SNPs) of Fpr1 in human colorectal cancer (CRC), and analyzed the association of Fpr1 SNPs with clinicopathological parameters and some specific diagnostic markers of CRC. Although the allele and genotype frequencies of Fpr1 SNPs in CRC tissues were not significantly different from that in whole blood cells derived from healthy Chinese subjects. Significant associations were observed between genotypes of c.289C>A and distant metastasis (P=0.001), and between genotypes of c.306T>C and tumor size (P=0.016). Genotypes of c.546C>A was closer to tumor size and lymphatic invasion (P=0.012 and P=0.043, respectively). Meanwhile, genotypes of c.1037C>A was related with tumor location and differentiation (P=0.000 and P=0.005, respectively). Besides, genotypes of c.576T>C>G was related with pathological type (P=0.000). Furthermore, several Fpr1 SNP positions including c.289 (C>A) and c.576 (G>C>T) were related to the expression of P53 (P=0.004 and P=0.008, respectively), and similar results were observed between other Fpr1 SNP positions and CEA, HER2 and Ki-67 (P<0.05). Our data demonstrate that Fpr1 SNPs may play the important role in the progression and metastasis of CRC.

Periodontal tissue destruction in aggressive periodontitis: Determination of gene or environmental factors

Aim

This study observed the role of defective neutrophil function in aggressive periodontitis through FPR1 gene polymorphism and the level of Il-8 compared with the role of dental plaque presence towards periodontal tissue damage (Clinical Attachment Loss/CAL) in patients in Indonesia.

Methods

Case-control study was used to detect differences in polymorphism expression of FPR1 gene, the level of Il-8, dental plaque, and Clinical Attachment Loss/CAL from 32 Aggressive Periodontitis (AP) and 29 Non-Aggressive Periodontitis (NAP) samples, selected with consecutive sampling method. Polymorphism was identified using polymerase chain reaction (PCR) technique, and the level of IL-8 in the gingival crevicular fluid was identified using the enzyme-linked immunosorbent assay (ELISA) test. The Clinical Attachment Loss was analysed by using William periodontal probe, and the oral environment analysis was performed by using the OHI-S plaque index. Statistical analysis was used to determine the significance of the polymorphism difference of FPR gene, Il-8, Plaque and CAL amongst all subjects and also the control and correlations among these factors.

Results

The results showed that in the Aggressive Periodontitis (AP), the presence of the polymorphism of c576 T > C > G of FPR1 gene caused as much as 5.04 times higher occurrence of aggressive periodontitis (p = 0.006; OR = 5.040 (1.51–16.74)). The low level of Il-8 (below 0.064 pg/μl), showed as much as 34.5 times higher occurrence of aggressive periodontitis (OR = 34.5 (6.76–176.08)). The oral hygiene of the AP samples were better significantly (p = 0.002), and on the Clinical Attachment Loss (CAL) sample was even more (p = 0.02). The polymorphism of c301 G > C of FPR1 gene correlated with the CAL (r = 0.37; p = 0.039). The polymorphism of c576 T > C > G correlated significantly with the Il-8 (r = 0.5; p = 0.0287). The polymorphism of c348 T > C correlated significantly with the dental plaque (r = 0.355; p = 0.049), whereas the dental plaque correlation with CAL was not significant.

Conclusion

The research conclusion showed that in aggressive periodontitis, genetic and environmental factors were correlated with the cause of periodontal tissue injury, and the role of genetic factors was more prominent on the injury.

Formyl-Peptide Receptors in Infection, Inflammation, and Cancer

Formyl-peptide receptors (FPRs) recognize bacterial and mitochondrial formylated peptides as well as endogenous non-formylated peptides and even lipids. FPRs are expressed on various host cell types but most strongly on neutrophils and macrophages. After the discovery of FPRs on leukocytes, it was assumed that these receptors predominantly govern a proinflammatory response resulting in chemotaxis, degranulation, and oxidative burst during infection. However, it is clear that the activation of FPRs has more complex consequences and can also promote the resolution of inflammation. Recent studies have highlighted associations between FPR function and inflammatory conditions, including inflammatory disorders, cancer, and infection. In this review we discuss these recent findings.

FPR1 interacts with CFH, HTRA1 and smoking in exudative age-related macular degeneration and polypoidal choroidal vasculopathy

PURPOSE

To determine the genetic association of an inflammation-related gene, formyl peptide receptor 1 (FPR1), in exudative age-related macular degeneration (AMD) and polypoidal choroidal vasculopathy (PCV).

METHODS

The coding region of FPR1 gene was sequenced in 554 unrelated Chinese individuals: 155 exudative AMD patients, 179 PCV patients, and 220 controls. Interactions and combined effects of FPR1 with complement factor H (CFH), high temperature requirement factor A1 (HTRA1), and smoking were also investigated.

RESULTS

A total of 28 polymorphisms in FPR1 were identified. Single nucleotide polymorphisms (SNP) rs78488639 increased the risk to exudative AMD (P=0.043) and PCV (P=0.016), whereas SNP rs867229 decreased the risk to exudative AMD (P=0.0026), but not PCV. Homozygous G allele of rs1042229 was associated with exudative AMD (P=0.0394, odds ratio (OR)=2.27, 95% confident interval: 1.08-4.74), but not with PCV. Exudative AMD, but not PCV, was associated with the heterozygous genotypes of rs2070746 (P=0.019, OR=0.57) and rs867229 (P=0.0082, OR=0.54). Significantly, interactions were identified among FPR1 rs78488639, CFH rs800292, and HTRA1 rs11200638 in both exudative AMD and PCV. Combined heterozygous risk alleles of CFH rs800292 GA and FPR1 rs78488639 CA were posed to PCV (P=2.22 × 10(-4), OR=10.47), but not exudative AMD. Furthermore, FPR1 rs78488639 CA combining with HTRA1 rs11200638 and smoking was also predisposed risks to exudative AMD and PCV.

CONCLUSION

FPR1 is associated with exudative AMD and PCV in a Hong Kong Chinese cohort. FPR1 rs78488639 interacted with CFH rs800292, HTRA1 rs11200638, and smoking, enhancing risk to exudative AMD and PCV.

V101L of human formyl peptide receptor 1 (FPR1) increases receptor affinity and augments the antagonism mediated by cyclosporins

Genetic variation plays a major role in drug response variability. CsA (cyclosporin A), a widely used immunosuppressive agent, is a specific antagonist for FPR1 (formyl peptide receptor 1), which is an important G-protein-coupled chemoattractant receptor in the innate immune system. In order to study the variable responses of cyclosporins to different FPR1 mutants, we investigated the distribution of human FPR1 haplotypes among 209 healthy Han Chinese subjects. The haplotype pattern in Han Chinese were characterized on the basis of five SNPs (single nucleotide polymorphisms), including rs5030878 (p.T11I), rs2070745 (p.V101L), rs5030880 (p.R190W), rs1042229 (p.N192K) and rs867228 (p.A346E). Receptor binding affinity of cyclosporins to FPR1 haplotypes was assessed using N-formyl-Nle-Leu-Phe-Nle-Tyr-Lys–FITC in CHO-G_α16 cells stably transfected with cDNAs encoding the top 12 FPR1 haplotypes in the Han Chinese. Variants of FPR1 carrying a single amino acid substitution of leucine for valine at position 101 (p.Leu¹⁰¹) displayed significantly higher pK_i values for CsA and CsH (cyclosporin H), indicative of an improved receptor affinity. The polymorphism of FPR1 p.Leu¹⁰¹ also enhanced the inhibitory effects of cyclosporins on fMLF (N-formyl-methionyl-leucyl-phenylalanine)-induced activities, including calcium mobilization, cell chemotaxis and MAPK (mitogen-activated protein kinase) phosphorylation. These results point to a possible complication for clinical use of CsA in patients carrying the p.Leu¹⁰¹ allele of FPR1.

Human formyl peptide receptor 1 C32T SNP interacts with age and is associated with blood pressure levels

BACKGROUND

Human formyl peptide receptor 1 (FPR1) mediates inflammatory responses, recognized as important participants in the physiopathology of hypertension. Similarly, FPR1 C32T SNP is associated with inflammation and BP related pathways. Therefore, the relationship between FPR1 C32T SNP, BP and hypertension needs to be investigated.

METHOD

1012 French middle-aged adults including 491 healthy individuals (5 years follow-up, T(+0) and T(+5)) and 521 hypertensive individuals were PCR-RFLP genotyped for FPR1 C32T SNP (rs5030878).

RESULTS

At entrance, there was no significant association between FPR1 C32T SNP and blood pressure (BP) in healthy individuals. However, 5 years later, significant associations were found for DBP, SBP (p<0.001 and p=0.009 respectively) and for their 5 years changes (Δ) (p=0.025 and p=0.027 for DBP and SBP respectively). Significant interactions between FPR1 C32T SNP and age on DBP, SBP, ΔDBP and ΔSBP were found (p=0.014, 0.008, 0.015 and 0.015 respectively). Consequently, stronger increase in BP was reported among healthy individuals aged less than 45 years. When normotensive individuals were compared to hypertensives ones, similar FPR1 C32T genotypes and allele frequency distributions were found.

CONCLUSION

FPR1 C32T SNP interacts with age, is associated with higher and a 5 years increase of BP levels in healthy individuals aged less than 45 years.