title: The asthma candidate gene NPSR1 mediates isoform specific downstream signalling.
abstract: BACKGROUND
  Neuropeptide S Receptor 1 (NPSR1, GPRA, GPR154) was first identified as an asthma candidate gene through positional cloning and has since been replicated as an asthma and allergy susceptibility gene in several independent association studies. In humans, NPSR1 encodes two G protein-coupled receptor variants, NPSR1-A and NPSR1-B, with unique intracellular C-termini. Both isoforms show distinct expression pattern in asthmatic airways. Although NPSR1-A has been extensively studied, functional differences and properties of NPSR1-B have not yet been clearly examined. Our objective was to investigate downstream signalling properties of NPSR1-B and functional differences between NPSR1-A and NPSR1-B.
  
  
  METHODS
  HEK-293 cells transiently overexpressing NPSR1-A or NPSR1-B were stimulated with the ligand neuropeptide S (NPS) and downstream signalling effects were monitored by genome-scale affymetrix expression-arrays. The results were verified by NPS concentration-response and time series analysis using qRT-PCR, cAMP and Ca²⁺ assays, and cAMP/PKA, MAPK/JNK and MAPK/ERK pathway specific reporter assays.
  
  
  RESULTS
  NPSR1-B signalled through the same pathways and regulated the same genes as NPSR1-A, but NPSR1-B yielded lower induction on effector genes than NPSR1-A, with one notable exception, CD69, a marker of regulatory T cells.
  
  
  CONCLUSIONS
  We conclude that NPSR1-B is regulating essentially identical set of genes as NPSR1-A, with few, but possibly important exceptions, and that NPSR1-A induces stronger signalling effects than NPSR1-B. Our findings suggest an isoform-specific link to pathogenetic processes in asthma and allergy.
authors.affiliation: Department of Biosciences and Nutrition, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Christina Orsmark
authors.initials: CO
authors.lastname: Pietras
authors.forename: Johanna
authors.initials: J
authors.lastname: Vendelin
authors.forename: Francesca
authors.initials: F
authors.lastname: Anedda
authors.forename: Sara
authors.initials: S
authors.lastname: Bruce
authors.forename: Mikael
authors.initials: M
authors.lastname: Adner
authors.forename: Lilli
authors.initials: L
authors.lastname: Sundman
authors.forename: Ville
authors.initials: V
authors.lastname: Pulkkinen
authors.forename: Harri
authors.initials: H
authors.lastname: Alenius
authors.forename: Mauro
authors.initials: M
authors.lastname: D'Amato
authors.forename: Cilla
authors.initials: C
authors.lastname: Söderhäll
authors.forename: Juha
authors.initials: J
authors.lastname: Kere
mesh_terms: D001249:Asthma / Q000235:genetics* / Q000503:physiopathology*; D000242:Cyclic AMP / Q000378:metabolism; D018076:DNA, Complementary / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D020022:Genetic Predisposition to Disease / Q000235:genetics; D057809:HEK293 Cells; D006801:Humans; D007668:Kidney / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D009479:Neuropeptides / Q000494:pharmacology; D020033:Protein Isoforms / Q000235:genetics / Q000502:physiology; D012313:RNA / Q000378:metabolism; D043562:Receptors, G-Protein-Coupled / Q000235:genetics* / Q000502:physiology*; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*
chemical_list: D018076:DNA, Complementary; C484532:NPSR1 protein, human; D009479:Neuropeptides; D020033:Protein Isoforms; D043562:Receptors, G-Protein-Coupled; C506531:neuropeptide S, human; D012313:RNA; D000242:Cyclic AMP