Expression of the apical iodide transporter in human thyroid tissues: a comparison study with other iodide transporters.
Iodide transport by thyrocytes involves two transporters, namely the Na(+)/I (-) symporter located at the basolateral pole and possibly pendrin in the apical membranes of the cell. Recently, we identified a human gene and its protein product, designated hAIT, as a putative new transporter involved in iodide transfer across the apical membrane of thyrocytes. In the present report, we analyzed both hAIT gene and protein expressions in a large series of benign and malignant human thyroid tissues. Using immunohistochemistry, hAIT staining was detected in normal thyroid tissue in about 10% of follicles; in positive follicles, 10-40% of thyrocytes, mostly the tall cells, were stained. In thyroid tissues obtained from patients with Graves' disease and toxic adenomas, hAIT mRNA and protein levels were similar to those found in normal tissue. In hypofunctioning adenomas, hAIT mRNA levels were slightly decreased, and apical iodide transporter (AIT) immunostaining was similar to that observed in normal thyroid tissue. AIT staining was stronger in Hürthle cell adenomas and in microfollicular adenomas. In thyroid carcinomas, the mean and median hAIT mRNA levels were significantly decreased. Expression of AIT protein was undetectable in most papillary carcinomas and was weak but detectable in most follicular carcinomas; it was negative in anaplastic carcinomas.
Department of Clinical Biology, Commissariat à l'Energie Atomique-LRC29V, Institut Gustave-Roussy, 94805 Villejuif Cedex, France.
Ludovic
L
Lacroix
Thierry
T
Pourcher
Claire
C
Magnon
Nicolas
N
Bellon
Monique
M
Talbot
Tosak
T
Intaraphairot
Bernard
B
Caillou
Martin
M
Schlumberger
Jean-Michel
JM
Bidart
D000236:Adenoma / Q000378:metabolism / Q000503:physiopathology; D002352:Carrier Proteins / Q000235:genetics; D027682:Cation Transport Proteins; D015870:Gene Expression; D006111:Graves Disease / Q000378:metabolism / Q000503:physiopathology*; D006801:Humans; D026901:Membrane Transport Proteins; D027501:Monocarboxylic Acid Transporters; D012333:RNA, Messenger / Q000032:analysis; D000076988:Sulfate Transporters; D027981:Symporters / Q000235:genetics* / Q000378:metabolism*; D013961:Thyroid Gland / Q000502:physiology*; D013964:Thyroid Neoplasms / Q000378:metabolism / Q000503:physiopathology; D000099209:Sodium-Iodide Symporters
D002352:Carrier Proteins; D027682:Cation Transport Proteins; D026901:Membrane Transport Proteins; D027501:Monocarboxylic Acid Transporters; D012333:RNA, Messenger; D000076988:Sulfate Transporters; D027981:Symporters; D000099209:Sodium-Iodide Symporters; C085609:SLC26A4 protein, human; C476760:SLC5A8 protein, human