Functional Toll-Like Receptor 4 Conferring Lipopolysaccharide Responsiveness Is Expressed in Thyroid Cells

NICOLA JP; VÉLEZ M; LUCERO AM; FOZZATTI L; PELLIZAS CG; MASINI - REPISO AM

ENDOCRINE SOC

Lugar: Chevy Chase, MD ; Año: 2009 vol. 150 p. 500 - 500

p>Lipopolysaccharide (LPS), a glycolipid found in the cell wall of Gram-negative bacteria, exerts pleiotropic biological effects in different cell types. LPS is mainly recognized by the Toll-like receptor (TLR) 4/MD2/Cluster of differentiation 14 complex (CD14). We previously demonstrated that LPS produced a direct action on thyroid cells, including up-regulation of thyroglobulin gene expression. This work aimed to study further the effect of LPS on thyroid function and to elucidate the mechanism by which LPS is recognized by the thyroid cell. We could detect the transcript and protein expression of TLR4, MD2, and CD14 in thyroid cells, and that these proteins are localized at the plasma membrane. The sodium iodide symporter (NIS) is the transporter involved in the iodide uptake, the first step in thyroid hormonogenesis. We demonstrated that LPS increases the TSH-induced iodide uptake and NIS protein expression. The LPS agonist lipid A reproduced LPS effect, whereas the LPS antagonist