title: STAT3 genotypic variation and cellular STAT3 activation and colon leukocyte recruitment in pediatric Crohn disease.
abstract: OBJECTIVE
  Genotypic variation in signal transducer and activator of transcription 3 (STAT3) increases risk for inflammatory bowel disease (IBD), and STAT3-dependent inflammatory networks are induced in the colon in these patients. We hypothesized that STAT3 "A" risk allele carriage would be associated with increased cellular STAT3 activation and colon leukocyte recruitment.
  
  
  METHODS
  Colonic expression of genes regulating STAT3 signaling and leukocyte recruitment and function was measured in pediatric patients with Crohn disease (CD) stratified by STAT3 genotype. The frequency of colonic pSTAT3* and CXCR2* neutrophils was determined using immunohistochemistry. STAT3 tyrosine phosphorylation (pSTAT3) was measured in circulating leukocytes by flow cytometry, and mechanisms regulating STAT3 activation were tested in IBD Epstein-Barr virus (EBV)-transformed lymphocytes (EBL).
  
  
  RESULTS
  Colonic expression of interleukin 6 (IL-6), the STAT3 target gene SOCS3, the neutrophil chemoattractants IL-8, CXCL1, and CXCL3, and the neutrophil products S100A8, S100A9, and S100A12 were increased in patients carrying the STAT3 "A" risk allele. The frequency of neutrophils expressing the cognate receptor for IL-8, CXCR2, was increased in colonic biopsies from patients carrying the risk allele, and the frequency of pSTAT3* or CXCR2* neutrophils correlated with histologic severity. The frequency of CD4 lymphocytes and granulocytes expressing pSTAT3 was increased in patients carrying the STAT3 "A" risk allele. EBLs from patients carrying the STAT3 "A" risk allele exhibited increased basal and IL-6-stimulated STAT3 tyrosine phosphorylation, increased transcription of STAT3 and SOCS3 after IL-6 stimulation, and increased membrane localization of the IL-6 receptor, GP130, and Janus-associated kinase 2.
  
  
  CONCLUSIONS
  The STAT3 "A" risk allele is associated with increased cellular STAT3 activation and upregulation of pathways that promote recruitment of CXCR2* neutrophils to the gut.
authors.affiliation: Division of Gastroenterology, Hepatology, and Nutrition, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, OH, USA.
authors.forename: Tara A
authors.initials: TA
authors.lastname: Willson
authors.forename: Benjamin R
authors.initials: BR
authors.lastname: Kuhn
authors.forename: Ingrid
authors.initials: I
authors.lastname: Jurickova
authors.forename: Shaina
authors.initials: S
authors.lastname: Gerad
authors.forename: David
authors.initials: D
authors.lastname: Moon
authors.forename: Erin
authors.initials: E
authors.lastname: Bonkowski
authors.forename: Rebecca
authors.initials: R
authors.lastname: Carey
authors.forename: Margaret H
authors.initials: MH
authors.lastname: Collins
authors.forename: Huan
authors.initials: H
authors.lastname: Xu
authors.forename: Anil G
authors.initials: AG
authors.lastname: Jegga
authors.forename: Stephen L
authors.initials: SL
authors.lastname: Guthery
authors.forename: Lee A
authors.initials: LA
authors.lastname: Denson
mesh_terms: D000293:Adolescent; D000483:Alleles; D001402:B-Lymphocytes / Q000378:metabolism; D015496:CD4-Positive T-Lymphocytes; D040501:Calgranulin A / Q000378:metabolism; D040502:Calgranulin B / Q000378:metabolism; D002478:Cells, Cultured; D054360:Chemokine CXCL1 / Q000378:metabolism; D019743:Chemokines, CXC / Q000235:genetics / Q000378:metabolism; D002648:Child; D003106:Colon / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D003424:Crohn Disease / Q000235:genetics* / Q000378:metabolism* / Q000473:pathology; D005260:Female; D015870:Gene Expression; D014644:Genetic Variation; D005838:Genotype; D006801:Humans; D007375:Interleukin-1 / Q000378:metabolism; D015850:Interleukin-6 / Q000235:genetics / Q000378:metabolism; D016209:Interleukin-8 / Q000235:genetics / Q000378:metabolism; D053614:Janus Kinase 2 / Q000378:metabolism; D018655:Lymphocyte Count; D008297:Male; D009504:Neutrophils / Q000378:metabolism*; D010766:Phosphorylation; D020641:Polymorphism, Single Nucleotide; D023063:Receptors, Interleukin-8B / Q000378:metabolism; D009418:S100 Proteins / Q000378:metabolism; D000067616:S100A12 Protein; D050796:STAT3 Transcription Factor / Q000235:genetics* / Q000378:metabolism; D015398:Signal Transduction / Q000235:genetics*; D000071223:Suppressor of Cytokine Signaling 3 Protein; D050826:Suppressor of Cytokine Signaling Proteins / Q000235:genetics / Q000378:metabolism; D014443:Tyrosine / Q000378:metabolism; D015854:Up-Regulation
chemical_list: C475829:CXCL1 protein, human; C499707:CXCL3 protein, human; D040501:Calgranulin A; D040502:Calgranulin B; D054360:Chemokine CXCL1; D019743:Chemokines, CXC; D007375:Interleukin-1; D015850:Interleukin-6; D016209:Interleukin-8; D023063:Receptors, Interleukin-8B; D009418:S100 Proteins; D000067616:S100A12 Protein; C090441:S100A12 protein, human; C106644:SOCS3 protein, human; D050796:STAT3 Transcription Factor; C494086:STAT3 protein, human; D000071223:Suppressor of Cytokine Signaling 3 Protein; D050826:Suppressor of Cytokine Signaling Proteins; D014443:Tyrosine; D053614:Janus Kinase 2