Multiple polymorphisms affect expression and function of the neuropeptide S receptor (NPSR1).
BACKGROUND
neuropeptide S (NPS) and its receptor NPSR1 act along the hypothalamic-pituitary-adrenal axis to modulate anxiety, fear responses, nociception and inflammation. The importance of the NPS-NPSR1 signaling pathway is highlighted by the observation that, in humans, NPSR1 polymorphism associates with asthma, inflammatory bowel disease, rheumatoid arthritis, panic disorders, and intermediate phenotypes of functional gastrointestinal disorders. Because of the genetic complexity at the NPSR1 locus, however, true causative variations remain to be identified, together with their specific effects on receptor expression or function. To gain insight into the mechanisms leading to NPSR1 disease-predisposing effects, we performed a thorough functional characterization of all NPSR1 promoter and coding SNPs commonly occurring in Caucasians (minor allele frequency >0.02).


RESULTS
we identified one promoter SNP (rs2530547 [-103]) that significantly affects luciferase expression in gene reporter assays and NPSR1 mRNA levels in human leukocytes. We also detected quantitative differences in NPS-induced genome-wide transcriptional profiles and CRE-dependent luciferase activities associated with three NPSR1 non-synonymous SNPs (rs324981 [Ile107Asn], rs34705969 [Cys197Phe], rs727162 [Arg241Ser]), with a coding variant exhibiting a loss-of-function phenotype (197Phe). Potential mechanistic explanations were sought with molecular modelling and bioinformatics, and a pilot study of 2230 IBD cases and controls provided initial support to the hypothesis that different cis-combinations of these functional SNPs variably affect disease risk.


CONCLUSIONS
these findings represent a first step to decipher NPSR1 locus complexity and its impact on several human conditions NPS antagonists have been recently described, and our results are of potential pharmacogenetic relevance.
Department of Biosciences and Nutrition, Karolinska Institutet, Stockholm, Sweden.
Francesca
F
Anedda
Marco
M
Zucchelli
Danika
D
Schepis
Anna
A
Hellquist
Lucia
L
Corrado
Sandra
S
D'Alfonso
Adnane
A
Achour
Gerald
G
McInerney
Alejandro
A
Bertorello
Mikael
M
Lördal
Ragnar
R
Befrits
Jan
J
Björk
Francesca
F
Bresso
Leif
L
Törkvist
Jonas
J
Halfvarson
Juha
J
Kere
Mauro
M
D'Amato
D001483:Base Sequence; D002460:Cell Line; D017931:DNA Primers; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D015870:Gene Expression; D006801:Humans; D008958:Models, Molecular; D020411:Oligonucleotide Array Sequence Analysis; D020641:Polymorphism, Single Nucleotide; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D043562:Receptors, G-Protein-Coupled / Q000737:chemistry / Q000235:genetics / Q000502:physiology*
D017931:DNA Primers; C484532:NPSR1 protein, human; D012333:RNA, Messenger; D043562:Receptors, G-Protein-Coupled