title: Upregulated mRNA expression of major histocompatibility complex class I chain-related gene A in colon and activated natural killer cells of Chinese patients with ulcerative colitis.
abstract: OBJECTIVE
  To explore the expression of major histocompatibility complex class I chain-related gene A (MICA) and its ligand in colonic mucosa and the role of MICA-natural killer (NK) group 2D (NKG2D) interaction in activating NK cells in ulcerative colitis (UC) patients.
  
  
  METHODS
  Intestinal mucosal biopsies were obtained from patients with UC and the controls. The expression of major histocompatibility complex class I-related gene (MIC) genes was determined by a reverse transcription polymerase chain reaction (RT-PCR) and the imaging of MICA expressed on colonic mucosa was measured by confocal microscopy resonance scanning. NKG2D and intracellular interferon (IFN)-γ expressions on NK cells were assayed by flow cytometry.
  
  
  RESULTS
  The relative amount of MICA mRNA in the colonic mucosa of UC patients was significantly higher than in that of the controls (3.5408 ± 2.6658 vs 1.0477 ± 0.7201, P = 0.001), as were the major histocompatibility complex class I chain-related gene B (MICB) (8.9879 ± 3.2893 vs 4.6293 ± 1.2616, P < 0.001) and NKG2D mRNA expression (2.4395 ± 0.8147 vs 1.1624 ± 0.3954, P < 0.001). Confocal microscopy resonance scanning had shown that MICA was localized predominantly on the basolateral membranes of the epithelium. Further flow cytometry confirmed that the percentage of IFN-γ producer NK cells that expressed NKG2D in peripheral blood lymphocytes was higher in UC patients than in the healthy controls (45.36% ± 12.47% vs 27.45% ± 9.30%, P < 0.001).
  
  
  CONCLUSIONS
  MICA, MICB and NKG2D were upregulated in the colonic mucosa of UC and were associated with activating NK cells with promoted NKG2D and IFN-γ production.
authors.affiliation: Department of Gastroenterology and Research Center of Digestive Diseases, Zhongnan Hospital, Wuhan University, Wuhan, Hubei Province, China.
authors.forename: Liu Qing
authors.initials: LQ
authors.lastname: Ge
authors.forename: Ting
authors.initials: T
authors.lastname: Jiang
authors.forename: Jie
authors.initials: J
authors.lastname: Zhao
authors.forename: Zhi Tao
authors.initials: ZT
authors.lastname: Chen
authors.forename: Feng
authors.initials: F
authors.lastname: Zhou
authors.forename: Bing
authors.initials: B
authors.lastname: Xia
mesh_terms: D000293:Adolescent; D000328:Adult; D016022:Case-Control Studies; D003093:Colitis, Ulcerative / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D003106:Colon / Q000378:metabolism*; D005260:Female; D005434:Flow Cytometry; D015870:Gene Expression; D015395:Histocompatibility Antigens Class I / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D006801:Humans; D007371:Interferon-gamma / Q000378:metabolism; D007413:Intestinal Mucosa / Q000276:immunology / Q000378:metabolism*; D007694:Killer Cells, Natural / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D055655:NK Cell Lectin-Like Receptor Subfamily K / Q000276:immunology*; D010446:Peptide Fragments / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015854:Up-Regulation; D055815:Young Adult
chemical_list: D015395:Histocompatibility Antigens Class I; C527085:KLRK1 protein, human; C099187:MHC class I-related chain A; C098080:MICB antigen; D055655:NK Cell Lectin-Like Receptor Subfamily K; D010446:Peptide Fragments; D012333:RNA, Messenger; C069261:interferon gamma (1-39); D007371:Interferon-gamma