title: All-trans-retinoic Acid Increases SLC26A3 DRA (Down-regulated in Adenoma) Expression in Intestinal Epithelial Cells via HNF-1β.
abstract: All-trans-retinoic acid (ATRA) is an active vitamin A derivative known to modulate a number of physiological processes, including growth and development, differentiation, and gene transcription. The protective effect of ATRA in gut inflammation and diarrheal diseases has been documented. In this regard, down-regulated in adenoma (DRA, a key luminal membrane Cl(-) transporter involved in NaCl absorption) has been shown to be suppressed in intestinal inflammation. This suppression of DRA is associated with diarrheal phenotype. Therefore, current studies were undertaken to examine the effects of ATRA on DRA expression. DRA mRNA levels were significantly elevated (∼4-fold) in response to ATRA with induction starting as early as 8 h of incubation. Similarly, ATRA increased DRA protein expression by ∼50%. Furthermore, DRA promoter activity was significantly increased in response to ATRA indicating transcriptional activation. ATRA effects on DRA expression appeared to be mediated via the RAR-β receptor subtype, as ATRA remarkably induced RAR-β mRNA levels, whereas RAR-β knockdown substantially attenuated the ability of ATRA to increase DRA expression. Results obtained from agonist (CH-55) and antagonist (LE-135) studies further confirmed that ATRA exerts its effects through RAR-β. Furthermore, ATRA treatment resulted in a significant increase in HNF-1β mRNA levels. The ability of ATRA to induce DRA expression was inhibited in the presence of HNF-1β siRNA indicative of its involvement in ATRA-induced effects on DRA expression. In conclusion, ATRA may act as an antidiarrheal agent by increasing DRA expression via the RAR-β/HNF-1β-dependent pathway.
authors.affiliation: Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois 60612.
authors.forename: Shubha
authors.initials: S
authors.lastname: Priyamvada
authors.affiliation: Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois 60612.
authors.forename: Arivarasu N
authors.initials: AN
authors.lastname: Anbazhagan
authors.affiliation: Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois 60612.
authors.forename: Tarunmeet
authors.initials: T
authors.lastname: Gujral
authors.affiliation: Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois 60612.
authors.forename: Alip
authors.initials: A
authors.lastname: Borthakur
authors.affiliation: Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois 60612.
authors.forename: Seema
authors.initials: S
authors.lastname: Saksena
authors.affiliation: Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois 60612.
authors.forename: Ravinder K
authors.initials: RK
authors.lastname: Gill
authors.affiliation: Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois 60612 From the Jesse Brown Veterans Affairs Medical Center.
authors.forename: Waddah A
authors.initials: WA
authors.lastname: Alrefai
authors.affiliation: Division of Gastroenterology and Hepatology, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois 60612 From the Jesse Brown Veterans Affairs Medical Center, pkdudeja@uic.edu.
authors.forename: Pradeep K
authors.initials: PK
authors.lastname: Dudeja
mesh_terms: D001483:Base Sequence; D018938:Caco-2 Cells; D027963:Chloride-Bicarbonate Antiporters / Q000235:genetics / Q000378:metabolism*; D017931:DNA Primers; D020868:Gene Silencing; D051539:Hepatocyte Nuclear Factor 1-beta / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D007413:Intestinal Mucosa / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000235:genetics; D034741:RNA, Small Interfering / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D018168:Receptors, Retinoic Acid / Q000235:genetics / Q000378:metabolism; D000076988:Sulfate Transporters; D014212:Tretinoin / Q000494:pharmacology*; D015854:Up-Regulation / Q000235:genetics
chemical_list: D027963:Chloride-Bicarbonate Antiporters; D017931:DNA Primers; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D018168:Receptors, Retinoic Acid; C081011:SLC26A3 protein, human; D000076988:Sulfate Transporters; D051539:Hepatocyte Nuclear Factor 1-beta; D014212:Tretinoin
keywords: chloride transport; epithelial cell; inflammation; intestinal epithelial; transporter