ABSTRACT
It has been suggested that the thyroid itself may contribute to the inflammatory process observed in autoimmune thyroiditis by releasing the cytokines interleukin-1α (IL-1α), interleukin-6 (IL-6) and interleukin-8 (IL-8), but studies of cytokine gene expression in thyrocytes have been limited and conflicting. A semi-quantitative reverse transcription-PCR technique has been used to investigate the expression of IL-1α, IL-6 and IL-8 mRNA in the human thyroid cell line HTori3 and in cultures of primary human thyroid follicular cells (TFCs). Cytokine mRNA levels were examined over a 24-h period, and the modulatory effects of exogenous IL-1α, interferon-γ (IFN-γ) and TSH investigated. Basal expression of IL-1α, IL-6 and IL-8 mRNA was detected in HTori3 and primary TFC cultures. Stimulation with IL-1 (10 U/ml) for 12 h produced an increase in the level of IL-1α mRNA in both primary TFC and HTori3 cultures. IL-6 and IL-8 mRNA levels were increased by the addition of IL-1 in both cell types, and this effect was detected throughout the 24-h time-course. IFN-γ (100 U/ml) had no significant effect on cytokine gene expression. A higher concentration of IFN-γ (500 U/ml) had no significant effect on the expression of IL-1α or IL-8 but produced an increase in the level of IL-6 mRNA in primary cultures and in HTori3 cells. Addition of TSH (1 mU/ml) produced an increase in the level of IL-1α mRNA in primary TFC and HTori3 cells, at 12 and 24 h. TSH had no significant effect on the expression of IL-6 or IL-8 mRNA. These results demonstrate that human TFCs constitutively express IL-1α, IL-6 and IL-8 mRNA and that this expression can be modulated by IL-1, IFN-γ and TSH.
β-Adrenergic stimulation of interleukin-1α and interleukin-6 expression in mouse brown adipocytes
