title: The Minor Allele of rs7574865 in the STAT4 Gene Is Associated with Increased mRNA and Protein Expression.
abstract: OBJECTIVE
  The T allele of rs7574865 in STAT4 confers risk of developing autoimmune disorders. However, its functional significance remains unclear. Here we analyze how rs7574865 affects the transcription of STAT4 and its protein expression.
  
  
  METHODS
  We studied 201 patients (80% female; median age, 54 years; median disease duration, 5.4 months) from PEARL study. Demographic, clinical, laboratory and therapeutic data were collected at each visit. IL-6 serum levels were measured by enzyme immune assay. The rs7574865 was genotyped using TaqMan probes. The expression levels of STAT4 mRNA were determined at 182 visits from 69 patients using quantitative real-time polymerase chain reaction. STAT4 protein was assessed by western blot in 62 samples from 34 patients. To determine the effect of different variables on the expression of STAT4 mRNA and protein, we performed multivariate longitudinal analyses using generalized linear models.
  
  
  RESULTS
  After adjustment for age, disease activity and glucocorticoid dose as confounders, the presence of at least one copy of the T allele of rs7574865 was significantly associated with higher levels of STAT4 mRNA. Similarly, TT patients showed significantly higher levels of STAT4 protein than GG patients. IL-6 induced STAT4 and STAT5 phosphorylation in peripheral blood lymphocytes. Patients carrying at least one T allele of rs7574865 displayed lower levels of serum IL-6 compared to GG homozygous; by contrast the production of C-reactive protein was similar in both populations.
  
  
  CONCLUSIONS
  Our data suggest that the presence of the rs7574865 T allele enhances STAT4 mRNA transcription and protein expression. It may enhance the signaling of molecules depending on the STAT4 pathway.
authors.affiliation: Servicio de Reumatología, Hospital Universitario de la Princesa, Instituto de Investigación Sanitaria Hospital Universitario La Princesa, Madrid, Spain.
authors.forename: Amalia
authors.initials: A
authors.lastname: Lamana
authors.affiliation: Departamento de Inmunología y Oncología, Centro Nacional de Biotecnología, CSIC, Madrid, Spain.
authors.forename: Mercedes
authors.initials: M
authors.lastname: López-Santalla
authors.affiliation: Servicio de Reumatología, Hospital Universitario de la Princesa, Instituto de Investigación Sanitaria Hospital Universitario La Princesa, Madrid, Spain.
authors.forename: Raquel
authors.initials: R
authors.lastname: Castillo-González
authors.affiliation: Servicio de Reumatología, Hospital Universitario de la Princesa, Instituto de Investigación Sanitaria Hospital Universitario La Princesa, Madrid, Spain.
authors.forename: Ana María
authors.initials: AM
authors.lastname: Ortiz
authors.affiliation: Instituto de Parasitología y Biomedicina López-Neyra, CSIC, Granada, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Martín
authors.affiliation: Servicio de Reumatología, Hospital Universitario de la Princesa, Instituto de Investigación Sanitaria Hospital Universitario La Princesa, Madrid, Spain.
authors.forename: Rosario
authors.initials: R
authors.lastname: García-Vicuña
authors.affiliation: Servicio de Reumatología, Hospital Universitario de la Princesa, Instituto de Investigación Sanitaria Hospital Universitario La Princesa, Madrid, Spain.
authors.forename: Isidoro
authors.initials: I
authors.lastname: González-Álvaro
mesh_terms: D000328:Adult; D000368:Aged; D000483:Alleles; D001168:Arthritis / Q000097:blood* / Q000235:genetics*; D005260:Female; D005786:Gene Expression Regulation; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006801:Humans; D007124:Immunoenzyme Techniques; D015850:Interleukin-6 / Q000097:blood; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D020641:Polymorphism, Single Nucleotide; D012333:RNA, Messenger / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D050797:STAT4 Transcription Factor / Q000235:genetics*; D015398:Signal Transduction
chemical_list: C508600:IL6 protein, human; D015850:Interleukin-6; D012333:RNA, Messenger; D050797:STAT4 Transcription Factor; C494090:STAT4 protein, human