ACTA ENDOCRINOLOGICA (BUC)

Radioactive iodine (RAI) therapy is a mainstay adjuvant treatment for thyroid cancer. Administration of RAI therapy after total or near-total thyroidectomy has shown a survival advantage in numerous properly selected patients. However, the role of RAI therapy after reoperation for persistent or recurrent differentiated thyroid carcinomas (DTCs) is unclear. One reason may be the possible downregulation of the I- transport system after primary surgery. RAI is transported by the sodium iodide symporter (NIS), PENDRIN, anoctamin 1 (ANO1) and cystic fibrosis transmembrane conductance regulator (CFTR) and emits β particles that destroy follicular cells. The identification of pathways of iodide (I-) transport has allowed use of the transport system to render tumours susceptible to RAI treatment via gene therapy. This review focuses on the effect of RAI therapy in follicular cell-derived thyroid cancers and offers potential novel targets that enable improved radioiodine uptake and thus an improved prognosis of thyroid cancer.

Background. Thyroid hormone participates in lipid metabolism regulation. However, the effects on triacyleride or triacylglycerol metabolism are complex and not fully clarified yet. In this study, we try to identify novel thyroid hormone-targeting lipogenic metabolic genes and analyze their molecular regulative mechanism. Method. Thirty-five promoters of twenty-nine human lipogenic regulative enzyme genes were constructed into pXP1 luciferase reporter plasmid (PFK2/FBP2-luc) and transfected into HeGP2 cells, respectively. Gene expression induced by triiodothyronine (T3) was detected by luciferase assay. The T3-activated gene promoter was then analyzed by sequence analysis, deletion and mutation, and electrophoretic mobility shift assay (EMSA). Results. After 10 nM T3 stimulation for 36 h, phosphogluconate dehydrogenase, malic enzyme, Glycerol- 3-phosphate acyltransferase (GPAT) 3, and 1-acylglycerol-3- phosphate O-acyltransferase (AGPAT) 2 were significantly activated, respectively. A AGGTCA-like-direct-repeat-4 consensus thyroid hormone response element (DR4-TRE)- like sequence was found in the GPAT3 promoter, which was then verified to be necessary for T3-induced GPAT3 activation by gene deletion and mutation analysis. EMSA further identified that T3-thyroid receptor (TR) α-retinoid-X receptor (RXR) complex directly bound on the GPAT3 promoter. Conclusion. Triiodothyronine could activate the GPAT3 through DR4-TRE-like sequence binding to participate in lipogenic regulation. AGPAT2 may be another thyroid hormone target enzyme.

Background. Thyroid-associated ophthalmopathy (TAO), one of the most common orbital diseases in adults, seriously reduces patients’ quality of life. Although human tear proteomics identified many abnormal expressed proteins and proposed several pathogeneses of TAO, most of these studies focused on the active stage or mixed types in TAO. In this study we identified significantly changed proteins and preliminary revealed the potential signalling pathways and mechanisms of TAO with the late, inactive stage. Patients and Methods. Tears from TAO patients (n=6) with a CAS score < 3 and 6 control healthy subject were collected. The pooled tears were further fractionated using high pH reversed-phase chromatography, then submitted to LC-MS/MS and subsequent bioinformatic analysis. Results. Proteomic profiling identified 107 significantly changed proteins between the inactive stage of TAO patients and healthy cases. Among these proteins, 62 were upregulated, and 45 were downregulated in TAO cases compared to healthy individuals. Enrichment analysis revealed that the immune system, cell cycle, metabolism (carbohydrate metabolism and metabolism of cofactors and vitamins), protein synthesis and degradation might play a vital role in the progress of inactive TAO. The present investigation represents the first proteomic tear study of TAO patients in the inactive stage. Conclusion. The results shed light on the differences between inactive TAO patients and healthy cases, thus enabling us to understand better the molecular mechanisms and potential targets for the treatment of inactive TAO.

Background. The cytotoxic T lymphocyteassociated molecules-4 (CTLA-4) is related to the relapse of Graves’ disease (GD) after anti-thyroid drugs (ATDs) withdrawal. We performed a meta-analysis to generate large-scale evidence on whether the CTLA-4 exon 1+49A/G polymorphism can predict the relapse of GD after ATDs withdrawal. Methods and Results. The PubMed, EMBASE,the Cochrane Library and reference lists of relevant studies were searched to identify eligible studies from inception to Jan, 2021. Ten eligible studies consisting of 1450 GD patients with a total of 848 relapsed patients were included in the meta-analysis. In Caucasians patients, the CTLA-4 exon 1+49A/G polymorphism significantly elevated the relapse risk of GD in additive (OR = 2.07, 95% CI: 1.18-3.62, P=0.011), dominant (OR = 2.52, 95% CI: 1.17-5.41, P=0.02), homozygote model(OR = 3.264, 95% CI: 1.25-8.52, P=0.016), except recessive (OR = 2.18, 95% CI = 0.98-4.86, P = 0.062) and heterozygote model (OR = 2.141, 95% CI = 0.958-4.786, P = 0.064). In Asian subgroup, none of these genotypes show any associations with the relapse of GD after ATDs withdrawal. Conclusion. This meta-analysis suggests that the CTLA-4 exon1 +49A/G polymorphism is associated with the relapse risk of GD after ATDs withdrawal in Caucasians, not Asians. Compared with the AA genotype, Caucasian patients with GG genotype have 3.264 times risk of relapse. A more aggressive treatment such as radioactive iodine or thyroidectomy, or longer periods treatment of ATDs should be recommended in Caucasian patients with the GG genotype.

Aim. To explore the effects and underlying mechanisms of pioglitazone (pio) on insulin sensitivity in insulin-resistant KKAy mice. Methods. Sixteen eight-week-old male KKAy mice were randomly assigned to two groups based on body weight: an insulin resistance model group and a pioglitazone treatment group (hereafter referred to as the pio-group). Eight male C57BL/6J mice were used as an insulin resistance control group. Mice in all three groups were fed an AIN-93G diet, and pio was added to the diet in the pio-group. After twelve weeks of treatment, blood glucose, serum insulin, glucose tolerance, and insulin tolerance were measured. ELISA was used to determine adiponectin and leptin in serum. A real time PCR assay was used to detect the mRNA of adiponectin and leptin in epididymal adipose tissue. A Western blot assay was used to analyze protein expression and/ or phosphorylation levels of peroxisome proliferator activated receptor γ (PPARγ), insulin receptor substrate 1 (IRS1), and protein kinase B (PKB/AKT) in the liver and epididymal adipose tissue.Results. The results showed that Pio treatment may effectively reduce levels of blood glucose and serum insulin, improve insulin tolerance and glucose tolerance, increase serum adiponectin, decrease serum leptin, and enhance mRNA expression of adiponectin in epididymal adipose tissue. Furthermore, with pio treatment, protein expression of PPARγ and phosphorylation levels of IRS1 and AKT were increased in the liver and epididymal adipose tissue. Conclusion. These results suggested that Pio intervention may ameliorate insulin resistance and improve insulin sensitivity in KKAy mice, which may be due to an increase of PPARγ and further activation of the insulin signaling transduction pathway (IRS1 and AKT) in the liver and epididymal adipose tissue of KKAy mice.