Ras oncoprotein disrupts the TSH/CREB signaling upstream adenylyl cyclase in human thyroid cell

High concentration of estradiol has a negative correlation with free thyroxine during the second trimester of pregnancy

Objective

To explore the relationship between estradiol (E2) and thyroid function during the second trimester of pregnancy and the effect of E2 on sodium iodide transporter (NIS) expression in cultured thyroid cells.

Materials and methods

We analyzed relationships between E2 and thyroid function in 196 pregnant women during the second trimester. Multiple linear regression analysis was performed between E2 and thyroid function. The human thyroid Nthy-ori3-1 cells were cultured in different E2 concentrations, and the mRNA levels of NIS, estrogen receptor (ER)-α, and ER-β were measured by quantitative real-time PCR. Their protein levels were assessed by western blot.

Results

E2 was positively correlated with thyroid-stimulating hormone (TSH) and negatively correlated with free thyroxine (FT4) (P < 0.05). When we corrected for age, BMI, alanine aminotransferase, and serum creatinine, E2 was still negatively correlated with FT4 (P < 0.5) during the second trimester. In Nthy-ori3-1 cells treated with 10 nM E2, NIS and ER-β mRNA levels were significantly reduced, while ER-α mRNA level was not altered (P > 0.5). Moreover, 10 nM E2 significantly decreased protein levels of ER-β, phosphorylated versions of protein kinase A (p-PKA), phosphorylated versions of cAMP response element-binding protein (p-CREB), and NIS, while treatment with the ER-β inhibitor restored the expression of p-PKA, p-CREB, and NIS (P < 0.05).

Conclusion

High concentration of E2 has a negative correlation with FT4. High concentration of E2 can inhibit the NIS expression through the ER-β-mediated pathway, which may cause thyroid hormone fluctuations during pregnancy.

Interaction of fluoride exposure and CREB1 gene polymorphisms on thyroid function in school-age children

OBJECTIVES

To evaluate the effects of CREB1 gene polymorphisms and long-term exposure to fluoride on thyroid function of children.

STUDY DESIGN

A total of 424 children (including 226 boys and 198 girls) aged 7-12 years old were enrolled in Kaifeng, China by cross-sectional study in 2017. The concentrations of urinary fluoride (UF) and creatinine (UCr) were measured using fluoride ion-selective electrode assay and creatinine assay kit (picric acid method), respectively. The concentration of UCr-adjusted UF (CUF) was calculated. Children were divided into high fluoride exposure group (HFG, CUF >1.41 mg/L) and low fluoride exposure group (LFG, CUF ≤1.41 mg/L) according to the median concentration of CUF (1.41 mg/L). The serum thyroid-stimulating hormone (TSH), total triiodothyronine (TT3) and total thyronine (TT4) levels were detected by the radiation immunoassay. The B-mode ultrasound was performed to test the thyroid volume (Tvol). Genotyping of CREB1 gene was conducted by a custom-by-design 48-plex SNPscan™ Kit. Associations between CUF concentration, CREB1 single nucleotide polymorphisms (SNPs) and thyroid function were assessed by multiple linear regression models.

RESULTS

Negative and positive associations between serum TT4 level (β = -0.721, 95%CI: -1.209, -0.234) and Tvol (β = 0.031, 95%CI: 0.011, 0.050) and CUF concentration were observed respectively. Children carrying CREB1 rs11904814 TG and rs2254137 AC genotypes had lower TT3 levels (P < 0.05). Children in HFG carrying rs11904814 TT, rs2253206 GG genotypes and rs6740584 C allele easily manifested lower serum TT4 levels (P < 0.05). Moreover, interactions between excessive fluoride exposure and CREB1 SNPs on Tvol were observed, and the interaction among different loci of CREB1 gene could modify serum TT3 level (P < 0.05, respectively).

CONCLUSIONS

Fluoride could alter children's serum TT4 levels and Tvol. Interactions between fluoride exposure and CREB1 polymorphisms may modify thyroid volume of children.