title: HSPA6 is an ulcerative colitis susceptibility factor that is induced by cigarette smoke and protects intestinal epithelial cells by stabilizing anti-apoptotic Bcl-XL.
abstract: Cigarette smoking ameliorates ulcerative colitis (UC) and aggravates Crohn's disease (CD). Cigarette smoke suppresses inflammation-induced apoptosis in intestinal epithelial cells (DLD-1), which may explain its protective effect in UC. Here, we performed transcriptome profiling of cigarette smoke extract (CSE)-exposed DLD-1 and Jurkat cells (T-lymphocytes) and related this to UC susceptibility genes with protective functions in the intestinal epithelium.
  
  
  
  CSE-regulated genes in DLD-1 and Jurkat cells were identified by Illumina microarrays and compared to genes in UC susceptibility loci. Colon biopsies were analyzed by immunohistochemistry for cell-specific expression of HSPA6. CSE-induced gene expression was analyzed by Q-PCR, Western blotting and immunofluorescence microscopy. Protein (HSPA6/Bcl-XL) interactions were analyzed by immunoprecipitation.
  
  
  
  CSE changed the expression of 536 and 2560 genes in DLD-1 and Jurkat cells, respectively. The "response to unfolded protein" was one of the most significantly affected gene sets with prominent induction (20.3-fold) of heat shock protein A6 (HSPA6). Six CSE-induced genes in DLD-1 cells were located in UC-susceptibility loci, including HSPA6 (rs1801274). HSPA6 is highly expressed in the human colonic epithelium. CSE caused a dose-dependent strong (>100-fold at 30% CSE for 6h), but transient induction of HSPA6 mRNA and protein in DLD-1 cells. HSPA6 co-immune precipitated with anti-apoptotic Bcl-XL, protein levels of which were increased while mRNA levels were unchanged.
  
  
  
  HSPA6 is a cigarette smoke-induced UC-susceptibility gene. The HSPA6 risk locus is associated with decreased HSPA6 expression. HSPA6 provides epithelial protection by stabilizing anti-apoptotic Bcl-XL, thereby contributing to the beneficial effect of cigarette smoking in UC.
authors.affiliation: Department of Gastroenterology and Hepatology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands. Electronic address: anoukregeling@gmail.com.
authors.forename: Anouk
authors.initials: A
authors.lastname: Regeling
authors.affiliation: Department of Gastroenterology and Hepatology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands. Electronic address: f.imhann@rug.nl.
authors.forename: Floris
authors.initials: F
authors.lastname: Imhann
authors.affiliation: Department of Laboratory Medicine, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands. Electronic address: haukeline@gmail.com.
authors.forename: Haukeline H
authors.initials: HH
authors.lastname: Volders
authors.affiliation: Department of Laboratory Medicine, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands. Electronic address: t.blokzijl@umcg.nl.
authors.forename: Tjasso
authors.initials: T
authors.lastname: Blokzijl
authors.affiliation: Department of Pediatrics, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands. Electronic address: v.w.bloks@umcg.nl.
authors.forename: Vincent W
authors.initials: VW
authors.lastname: Bloks
authors.affiliation: Department of Gastroenterology and Hepatology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands. Electronic address: r.k.weersma@umcg.nl.
authors.forename: Rinse K
authors.initials: RK
authors.lastname: Weersma
authors.affiliation: Department of Gastroenterology and Hepatology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands. Electronic address: gerard.dijkstra@umcg.nl.
authors.forename: Gerard
authors.initials: G
authors.lastname: Dijkstra
authors.affiliation: Department of Gastroenterology and Hepatology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands. Electronic address: k.n.faber@umcg.nl.
authors.forename: Klaas Nico
authors.initials: KN
authors.lastname: Faber
mesh_terms: D000328:Adult; D000368:Aged; D003093:Colitis, Ulcerative / Q000209:etiology / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D004847:Epithelial Cells / Q000378:metabolism* / Q000473:pathology; D005260:Female; D020022:Genetic Predisposition to Disease; D018840:HSP70 Heat-Shock Proteins / Q000096:biosynthesis* / Q000235:genetics; D006801:Humans; D007413:Intestinal Mucosa / Q000378:metabolism* / Q000473:pathology; D019169:Jurkat Cells; D008297:Male; D008875:Middle Aged; D055550:Protein Stability; D012906:Smoke / Q000009:adverse effects; D012907:Smoking / Q000009:adverse effects / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D051020:bcl-X Protein / Q000235:genetics / Q000378:metabolism*
chemical_list: C494811:BCL2L1 protein, human; D018840:HSP70 Heat-Shock Proteins; C544598:HSPA6 protein, human; D012906:Smoke; D051020:bcl-X Protein
keywords: Apoptosis; Cigarette smoke; Heat shock protein A6; Intestinal epithelium; Ulcerative colitis