TY - JOUR
T1 - Dual oxidase2 is expressed all along the digestive tract
AU - El Hassani, Rabii Ameziane
AU - Benfares, Nesrine
AU - Caillou, Bernard
AU - Talbot, Monique
AU - Sabourin, Jean Christophe
AU - Belotte, Virginie
AU - Morand, Stanislas
AU - Gnidehou, Sédami
AU - Agnandji, Diane
AU - Ohayon, Renée
AU - Kaniewski, Jacques
AU - Noël-Hudson, Marie Sophie
AU - Bidart, Jean Michel
AU - Schlumberger, Martin
AU - Virion, Alain
AU - Dupuy, Corinne
PY - 2005/5/1
Y1 - 2005/5/1
N2 - The dual oxidase (Duox)2 flavoprotein is strongly expressed in the thyroid gland, where it plays a critical role in the synthesis of thyroid hormones by providing thyroperoxidase with H2O2. DUOX2 mRNA was recently detected by RT-PCR and in-situ hybridization experiments in other tissues, such as rat colon and rat and human epithelial cells from the salivary excretory ducts and rectal glands. We examined Duox2 expression at the protein level throughout the porcine digestive tract and in human colon. Western blot analysis identified Duox2 as the same two molecular species (Mr 165 and 175 kDa) as detected in the thyroid. It was expressed in all the tissues tested, but the highest levels were found in the cecum and sigmoidal colon. Immunohistochemical studies showed that Duox2 protein is mainly present in these parts of the gut and located at the apical membrane of the enterocytes in the brush border, indicating that it is expressed only in highly differentiated cells. A Ca2+/NADPH-dependent H2O2-generating system was associated with Duox2 protein expression, which had the same biochemical characteristics as the NADPH oxidase in the thyroid. Indeed, treatment of the thyroid and cecum particulate fractions with phenylarsine oxide resulted in complete calcium desensitization of both enzymes. A marked increase in DUOX2 expression was also found during spontaneous differentiation of postconfluent Caco-2 cells. The discovery of Duox2 as a novel source of H 2O2 in the digestive tract, particularly in the cecum and colon, makes it a new candidate mediator of physiopathological processes.
AB - The dual oxidase (Duox)2 flavoprotein is strongly expressed in the thyroid gland, where it plays a critical role in the synthesis of thyroid hormones by providing thyroperoxidase with H2O2. DUOX2 mRNA was recently detected by RT-PCR and in-situ hybridization experiments in other tissues, such as rat colon and rat and human epithelial cells from the salivary excretory ducts and rectal glands. We examined Duox2 expression at the protein level throughout the porcine digestive tract and in human colon. Western blot analysis identified Duox2 as the same two molecular species (Mr 165 and 175 kDa) as detected in the thyroid. It was expressed in all the tissues tested, but the highest levels were found in the cecum and sigmoidal colon. Immunohistochemical studies showed that Duox2 protein is mainly present in these parts of the gut and located at the apical membrane of the enterocytes in the brush border, indicating that it is expressed only in highly differentiated cells. A Ca2+/NADPH-dependent H2O2-generating system was associated with Duox2 protein expression, which had the same biochemical characteristics as the NADPH oxidase in the thyroid. Indeed, treatment of the thyroid and cecum particulate fractions with phenylarsine oxide resulted in complete calcium desensitization of both enzymes. A marked increase in DUOX2 expression was also found during spontaneous differentiation of postconfluent Caco-2 cells. The discovery of Duox2 as a novel source of H 2O2 in the digestive tract, particularly in the cecum and colon, makes it a new candidate mediator of physiopathological processes.
KW - Dual oxidase gene
KW - Gastrointestinal system
KW - Hydrogen peroxide
KW - NADPH oxidase
KW - Thyroid gland
KW - Thyroid oxidase gene
UR - http://www.scopus.com/inward/record.url?scp=20244385005&partnerID=8YFLogxK
U2 - 10.1152/ajpgi.00198.2004
DO - 10.1152/ajpgi.00198.2004
M3 - Article
C2 - 15591162
AN - SCOPUS:20244385005
SN - 0193-1857
VL - 288
SP - G933-G942
JO - American Journal of Physiology - Gastrointestinal and Liver Physiology
JF - American Journal of Physiology - Gastrointestinal and Liver Physiology
IS - 5 51-5
ER -