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

Genetic variation plays a major role in drug response variability. Cyclosporin A (CsA), a widely used immunosuppressive agent, is a specific antagonist for formyl peptide receptor 1 (FPR1), 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 based on five single nucleotide polymorphisms (SNPs), 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 fNle-Leu-Phe-Nle-Tyr-Lys-fluorescein in CHO-Gα16 cells stably transfected with cDNAs encoding the top 12 FPR1 haplotypes in Han Chinese. Variants of FPR1 carrying a single amino acid substitution of leucine for valine at position 101 (p.L101) displayed significantly higher pKi values for CsA and CsH, indicative of an improved receptor affinity. The polymorphism of FPR1 p.L101 also enhanced the inhibitory effects of cyclosporins on fMLF-induced activities including calcium mobilization, cell chemotaxis and MAPK phosphorylation. These results point to a possible complication for clinical use of CsA in patients carrying the p.L101 allele of FPR1.
Source: BJ Gene - Category: Biochemistry Authors: Tags: BJ Gene Source Type: research