Palmitic Acid Downregulates Thyroglobulin (Tg), Sodium Iodide Symporter (NIS), and Thyroperoxidase (TPO) in Human Primary Thyrocytes: A Potential Mechanism by Which Lipotoxicity Affects Thyroid?

Figure 3

Palmitic acid downregulates the expression of thyroglobulin (Tg), sodium iodide symporter (NIS), and thyroperoxidase (TPO) in human primary thyrocytes. (a) The mRNA levels of Tg, NIS (SLC5A5), and TPO in cells stimulated with palmitic acid for 24 hours ( to 5). (b) Dose-dependent effects of palmitic acid on the protein levels of Tg, NIS, and TPO for 72 hours detected by Western blot. (c) The protein levels of Tg, NIS, and TPO detected by immunofluorescence in cells stimulated with palmitic acid at 0.2 mM for 72 hours. Scale bars, 20 μm. (d) The relative protein levels from Western blot assays for Tg, NIS, and TPO was quantified by densitometry and normalized with GAPDH. (e) The relative fluorescence intensity from immunofluorescence assays for Tg, NIS, and TPO. In all panels, representative data from 3 to 7 independent experiments are shown. All data are expressed as the mean ± standard deviation. and versus human primary thyrocytes without palmitic acid stimulation; versus human primary thyrocytes stimulated with palmitic acid at 0.2 mM. The error bars represent the standard deviations. PA: palmitic acid; Tg: thyroglobulin; SLC5A5: gene name of sodium iodide symporter; TPO: thyroperoxidase.

(a)

(b)

(c)

(d)

(e)