Cell biology of H2O2 generation in the thyroid: investigation of the control of dual oxidases (DUOX) activity in intact ex vivo thyroid tissue and cell lines.

H2O2 generation by dual oxidase (DUOX) at the apex of thyroid cells is the limiting factor in the oxidation of iodide and the synthesis of thyroid hormones. Its characteristics have been investigated using different in vitro models, from the most physiological thyroid slices to the particulate fraction isolated from transfected DUOX expressing CHO cells. Comparison of the models shows that some positive controls are thyroid specific (TSH) or require the substructure of the in vivo cells (MβCD).

Intracellular expression of reactive oxygen species-generating NADPH oxidase NOX4 in normal and cancer thyroid tissues.

NADPH oxidase 4 (NOX4) belongs to the NOX family that generates reactive oxygen species (ROS). Function and tissue distribution of NOX4 have not yet been entirely clarified. To date, in the thyroid gland, only DUOX1/2 NOX systems have been described.

Poorly differentiated follicular thyroid carcinoma: prognostic factors and relevance of histological classification.

Objective: Poorly differentiated follicular thyroid carcinoma (PDFC) is a tumor of follicular cell origin with attributes intermediate between well-differentiated carcinomas and anaplastic carcinomas, but neither a clear histological description nor an established definition of prognostic indicators are available.

Design: This study correlates the clinical outcome and survival of 40 PDFC patients with histological architecture, cytological characteristics, and expression of various markers of cell proliferation and differentiation (cyclin A, cyclin B1, cyclin D1, cyclin E, Ki67, thyroperoxidase, galectin 3, dual oxidase [Duox], vascular endothelial growth factor, epidermal growth factor receptor, and p53).

Main Outcome: At 5 years, the overall survival rate was 63% and the metastasis-free survival rate was 57%.

Cloning and characterization of a novel isoform of iodotyrosine dehalogenase 1 (DEHAL1) DEHAL1C from human thyroid: comparisons with DEHAL1 and DEHAL1B.

The human iodotyrosine dehalogenase 1 (DEHAL1) gene is composed of six exons. Two isoforms (DEHAL1 and DEHAL1B) have been published in GenBank, both of which have a nitroreductase domain and arise from differential splicing in exon 5. We recently showed that the DEHAL1 isoform is a transmembrane protein that efficiently catalyzes the NADPH-dependent deiodination of mono (L-MIT) and diiodotyrosine (L-DIT) in human embryonic kidney-293 (HEK293) cells.

Dual oxidase-2 has an intrinsic Ca2+-dependent H2O2-generating activity.

Duox2 (and probably Duox1) is a glycoflavoprotein involved in thyroid hormone biosynthesis, as the thyroid H2O2 generator functionally associated with Tpo (thyroperoxidase). So far, because of the impairment of maturation and of the targeting process, transfecting DUOX into nonthyroid cell lines has not led to the expression of a functional H2O2-generating system at the plasma membrane. For the first time, we investigated the H2O2-generating activity in the particulate fractions from DUOX2- and DUOX1-transfected HEK293 and Chinese hamster ovary cells.