Forty-five pregnant women who underwent cesarean section, including 30 cases of gestational diabetes mellitus (GDM) and 15 normal pregnant women, were enrolled in this study to examine the differential expression of circular RNAs (circRNAs) in the placentas of women with GDM by RNA sequencing (RNA-seq) analysis. The differentially expressed circRNAs were analyzed bioinformatically using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment and circRNA-microRNA (miRNA) interaction prediction. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to verify the results. A total of 8,321 circRNAs were identified in the human placenta, among which 46 were differentially expressed (fold change ≥2 and p < 0.05), including three that were upregulated and 43 that were downregulated. According to the GO and KEGG enrichment results, these circRNAs may be associated with vital biological processes, cellular components, molecular functions, and signaling pathways. In particular, KEGG analysis shown they may be involved in advanced glycation end products-receptor for advanced glycation end products (AGE-RAGE) signaling pathway in diabetic complications, indicating that these circRNAs might participate in the occurrence and pathogenesis of GDM. qRT-PCR verified that the expression of circ_5824, circ_3636, and circ_0395 was consistent with RNA-seq analysis; their expression levels were significantly lower in the GDM group than in the control group. The circRNA-miRNA interaction was analyzed according to the molecular sponge mechanism, and its potential function is discussed. These results shed light on future functional studies of circRNAs related to GDM.

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Thyroid stimulating hormone (TSH) consists of an α-subunit and a unique β-subunit. The first in-frame TSHβ splice variant produced by the cells of immune system was identified in 2009. The TSHβ splice variant and native TSHβ exhibit different expression profiles, and research has been conducted to elucidate the role of the TSHβ splice variant in different diseases. However, understanding of the fundamental physiological characteristics of the TSHβ splice variant is currently limited. To verify whether the TSHβ splice variant has the potential to induce thyroid follicular cells to synthesize thyroid hormone, in vivo and in vitro stimulation experiments were conducted in the present study. A total of 60 C57BL/6 mice were divided into control-, 5 and 10 µg TSHβ splice variant-treated groups at random. Mice were sacrificed at 0.5, 1 and 4 h after intraperitoneal injection, and serum levels of tri-iodothyronine (T3) and thyroxine (T4) were determined using a radioimmunoassay. Thyroid follicular cells were isolated from the thyroids of mice, and stimulated with 2 µg/ml TSHβ splice variant. Supernatants were collected, and the levels of T3 and T4 were detected. The protein expression levels of the sodium-iodide symporter, thyroperoxidase and thyroglobulin in thyroid follicular cells were quantified using western blot analysis. To verify whether the TSHβ splice variant expression was regulated by the hypothalamus-pituitary-thyroid (HPT) axis, similar to native TSHβ, a total of 60 C57BL/6 mice were equally divided into control, 2 mg/kg T3 intraperitoneal injection and 0.05 mg/kg thyroid-releasing hormone intraperitoneal injection groups at random. Mice were sacrificed at 1 and 4 h after injection. Alterations in the expression of the TSHβ splice variant in the pituitary, thyroid, peripheral blood leukocytes and spleen tissues were detected using western blot analysis. The present study demonstrated that the TSHβ splice variant is not regulated by the HPT axis and may affect thyroid hormone synthesis. Modifications in the expression of the TSHβ splice variant may occur in a uniquely regulated manner to provide peripheral immunological compartments with a source of activated cells, particularly under immune stress.

Background:Gestational diabetes mellitus (GDM) is a common complication during pregnancy. Obesity and overweight are closely related to metabolic diseases and diabetes. However, the role of adipose tissue in the pathogenesis of GDM remains to be studied. The aim of this study was to investigate the correlation of vitamin D (VD) levels, VD receptor (VDR), and peroxisome proliferator-activated receptor γ (PPARγ) expression with GDM in overweight or obese women.Methods:One hundred and forty pregnant women with full-term single-birth cesarean-section were selected as the study subjects and grouped (70 GDM women, including 35 non-overweight/non-obese women [group G1] and 35 women with overweight or obesity [group G2]; 70 pregnant women with normal glucose tolerance, including 35 non-overweight/non-obese women [group N1] and 35 overweight/obese women [group N2]). The levels of serum VD, blood biochemistry, and adiponectin were compared in these women. Subcutaneous adipose tissue was isolated from the abdominal wall incision. VDR and PPARγ messenger RNA (mRNA) transcript levels in these adipose tissues were quantified by real-time polymerase chain reaction. The differences between the levels of PPARγ protein and phosphorylated PPARγ Ser273 were detected by Western blotting.Results:The serum VD level of GDM women was lower in comparison to that of women with normal glucose tolerance (G1 vs. N1: 20.62 ± 7.87 ng/mL vs. 25.85 ± 7.29 ng/mL, G2 vs. N2: 17.06 ± 6.74 ng/mL vs. 21.62 ± 7.18 ng/mL, P < 0.05), and the lowest in overweight/obese GDM women. VDR and PPARγ mRNA expression was higher in the adipose tissues of GDM women in comparison to that of women with normal glucose tolerance (VDR mRNA: G1 vs. N1: 210.00 [90.58–311.46] vs. 89.34 [63.74–159.92], G2 vs. N2: 298.67 [170.84–451.25] vs. 198.28 [119.46–261.23], PPARγ mRNA: G1 vs. N1: 100.72 [88.61–123.87] vs. 87.52 [66.37–100.04], G2 vs. N2: 117.33 [100.08–149.00] vs. 89.90 [76.95–109.09], P < 0.05), and their expression was the highest in GDM + overweight/obese women. VDR mRNA levels positively correlated with the pre-pregnancy body mass index (BMI), pre-delivery BMI, fasting blood glucose (FBG), homeostasis model assessment of insulin resistance (HOMA-IR), and PPARγ mRNA while it negatively correlated with the VD and the adiponectin levels (r = 0.395, 0.336, 0.240, 0.190, 0.235, –0.350, –0.294, respectively, P < 0.05). The degree of PPARγ Ser273 phosphorylation increased in obese and GDM pregnant women. PPARγ mRNA levels positively correlated with pre-pregnancy BMI, pre-delivery BMI, FBG, HOMA-IR, serum total cholesterol, triglyceride, free fatty acid, and VDR mRNA, while it negatively correlated with the VD and adiponectin levels (r = 0.276, 0.199, 0.210, 0.230, 0.182, 0.214, 0.270, 0.235, –0.232, –0.199, respectively, P < 0.05).Conclusions:Both GDM and overweight/obese women had decreased serum VD levels and up-regulated VDR and PPARγ mRNA expression in adipose tissue, which was further higher in the overweight or obese women with GDM. VD may regulate the forma...