Bacterial lipopolisaccharide stimulates the TSH dependent thyroglobulin gene expression at transcriptional level by involving TTF-1 and Pax8 transription factors

MARÍA L. VÉLEZ, EUGENIA COSTAMAGNA, EDNA T. KIMURA, LAURA FOZZATTI, CLAUDIA G, PELLIZAS, MARÍA M. MONTESINOS, ARIEL M. LUCERO, ALDO H. COLEONI, PILAR SANTISTEBAN, ANA M. MASINI-REPISO

ENDOCRINOLOGY

The Endocrine Society

Lugar: Bethesda, MD, USA; Año: 2006 vol. 147 p. 3260 - 3260

0013-7227

font face="Times-Roman"> The bacterial lipopolysaccharide (LPS) is a biological activator that induces multiple gene expression in several cell types. LPS has been proposed as an etiopathogenic agent in autoimmune diseases. However, whether LPS affects the expression of autoantigens has not been explored. Thyroglobulin (TG) is a key protein in the thyroid hormonogenesis and one of the major thyroid autoantigens. This study aimed to analyze the action of LPS on the TG gene expression in FRTL-5 thyroid cells. We demonstrated that LPS increased the TSH-induced TG protein and mRNA level. Evidence that the effect of LPS was exerted at transcriptional level was obtained by transfecting the minimal TG promoter. The C element of the TG promoter, which contains sequences for Pax8 and TTF-1 binding, is essential for the TG promoter full expression under TSH stimulation. We observed that the transcriptional activity of a construct containing five tandem repeats of the C site was