Jiajun Zhao

Involvement of chronic stresses in rat islet and INS-1 cell glucotoxicity induced by intermittent high glucose

In order to investigate the toxic effect of intermittent high glucose (IHG) and sustained high glucose (SHG) on rat pancreatic beta cell functions and the potential involved mechanisms, isolated rat islets and INS-1 beta cells were exposed to SHG (25 mmol/l) or IHG (11.1 and 25 mmol/l glucose alternating every 12 h) for 72 h. The results showed that IHG induced a more significant impairment of insulin release response in rat islets and INS-1 cell than SHG. Simultaneously, the intracellular levels of endoplasmic reticulum and oxidative stress were more markedly increased in islets and INS-1 cells exposed to IHG. However, there was no significant difference between reducing cell viability, insulin content and gene expression induced by SHG and IHG. Taken together, this study suggested the more serious toxic effect on rat pancreatic beta cell function induced by IHG treatment may be due to excessive activation of cellular stress.

Iodine Status and Prevalence of Thyroid Disorders After Introduction of Mandatory Universal Salt Iodization for 16 Years in China: A Cross-Sectional Study in 10 Cities

BACKGROUNDnThe goal of eliminating iodine deficiency worldwide was successfully achieved in China after the implementation of a mandatory universal salt iodization program for the last 16 years. Thus, China has been assessed as a country with more than adequate iodine levels. This survey aimed to investigate the current iodine status in China and the effects of an increased iodine intake on the spectrum and prevalence of thyroid disorders.nnnMETHODSnA total of 15,008 adult subjects from 10 cities in eastern and central China were investigated. Serum thyrotropin (TSH), thyroid peroxidase antibodies (TPOAb), thyroglobulin antibodies (TgAb), and urine iodine concentration (UIC) were measured, and an ultrasonography of the thyroid was performed in all subjects. Free thyroxine (fT4) and free triiodothyronine (fT3) levels were only measured if the serum TSH was outside the normal range.nnnRESULTSnThe median UIC values were 197u2009μg/L in school-age children (SAC) and 205u2009μg/L in a cohort population. Six cities were classified as regions with adequate iodine intake (AII), and four cities as regions with more than adequate iodine intake (MTAII), according to median SAC UIC. The prevalence of clinical hypothyroidism, subclinical hypothyroidism, and positive thyroid antibodies was significantly higher in MTAII cities than it was in AII cities. Moreover, the prevalence of clinical hyperthyroidism (1.1% vs. 0.8%, pu2009=u20090.033) and Graves disease (0.8% vs. 0.5%, pu2009=u20090.019) also significantly increased in MTAII cities. Compared with a five-year prospective study conducted in 1999, the prevalence of goiter significantly decreased (2.9% vs. 5.02%, pu2009=u20090.001), but there was a significant increase in thyroid nodules (12.8% vs. 2.78%, pu2009=u20090.001). The prevalence of subclinical hypothyroidism (16.7% vs. 3.22%), positive TPOAb (11.5% vs. 9.81%), and positive TgAb (12.6% vs. 9.09%) significantly increased, while no changes were seen in clinical hyperthyroidism, subclinical hyperthyroidism, or Graves disease.nnnCONCLUSIONnThe goal of eliminating iodine deficiency has been successfully achieved in China. However, the prevalence and spectrum of thyroid disorders has increased, reflecting possible adverse effects of increased iodine intake.

NKG2D Ligands Expression and NKG2D-Mediated Cytotoxicity in Human Laryngeal Squamous Carcinoma Cells

The NKG2D is an activating immunoreceptor expressed by NK cells and CD8+ T cells. Engagement of NKG2D by its ligands is critical for both innate and adoptive immunity. While the overexpression of NKG2D ligands on certain tumour cells has previously been demonstrated, little is known about NKG2D ligand expression on human laryngeal tumour cells. In this study, we first verified that the interaction between NKG2D and its ligands was critical for NK cell‐based immune response to human laryngeal squamous carcinoma cells Hep‐2. This NKG2D‐mediated effect was observed by transfecting the recombinant eukaryotic expression vector pEGFP‐N1/NKG2D as well as the NKG2D blockade. The mRNA and protein expression of NKG2D ligands, MHC class I‐related chain molecules A (MICA) and UL16‐binding proteins (ULBPs), in human laryngeal carcinoma cell line Hep‐2 and fresh tumour tissues were evaluated. Compared with non‐tumour tissues of vocal cords polyps, MICA and ULBP‐3 were strongly overexpressed on both the human laryngeal carcinoma cell line Hep‐2 and fresh human laryngeal carcinoma tissues. The mechanism and impact of NKG2D ligands overexpression on NK cell‐mediated anti‐laryngeal cancer immune response would require further investigation.

Benefits of Levothyroxine Replacement Therapy on Nonalcoholic Fatty Liver Disease in Subclinical Hypothyroidism Patients

Objectives. To evaluate the effect of levothyroxine (LT4) replacement therapy on nonalcoholic fatty liver disease (NAFLD) in subclinical hypothyroidism (SCH) patients. Methods. This study was a post hoc analysis of a randomized controlled trial and involved 33 significant and 330 mild SCH patients. All of the significant SCH patients received LT4 supplement. The mild SCH patients were grouped as LT4 treated or not. After 15 months of follow-up, prevalence of NAFLD in each group was reevaluated. Subgroup analysis was conducted in mild SCH patients with dyslipidemia. Results. After treatment with LT4, the prevalence of NAFLD in significant SCH patients reduced from 48.5% to 24.2% (p = 0.041). In mild SCH patients, prevalence of NAFLD and serum alanine aminotransferase (ALT) was not significantly affected by LT4 supplementation. Nonetheless, mild SCH patients with dyslipidemia who received LT4 treatment experienced decreases in the prevalence of NAFLD and serum ALT levels (p < 0.05 for both). In contrast, these parameters remained comparably stable in patients who were not treated. Conclusion. LT4 supplementation has benefits on NAFLD in significant SCH patients or mild SCH patients with dyslipidemia. For NAFLD patients with SCH, appropriate supplementation of LT4 may be an effective means of controlling NAFLD. The original trial was registered with ClinicalTrials.gov (NCT01848171).

Association of maternal serum lipids at late gestation with the risk of neonatal macrosomia in women without diabetes mellitus

BackgroundMacrosomia is a serious public health problem worldwide due to its increasing prevalence and adverse influences on maternal and neonatal outcomes. Maternal dyslipidemia exerts potential and adverse impacts on pregnant women and newborns. However, the association between maternal serum lipids and the risk of macrosomia has not yet been clearly elucidated. We explored the association between the maternal lipids profile at late gestation and the risk of having macrosomia among women without diabetes mellitus (DM).MethodsThe medical records of 5407 pregnant women giving birth to single live babies at term were retrospectively analyzed. Subjects with DM, hypertension, thyroid disorders and fetal malformation were excluded. Maternal fasting serum lipids were measured during late pregnancy. Logistic regression analysis was used to analyze the variables associated with the risk of macrosomia.ResultsMaternal serum triglyceride (TG) and high-density lipoprotein cholesterol (HDL-C) levels were related to macrosomia; each 1xa0mmol/L increase in TG resulted in a 27% increase in macrosomia risk, while each 1xa0mmol/L increase in HDL-C level resulted in a 37% decrease in macrosomia risk, even after adjusting for potential confounders. Notably, the risk of macrosomia increased progressively with increased maternal serum TG levels and decreased HDL-C levels. Compared with women with serum TG levels <u20092.5xa0mmol/L, women with TG levels greater than 3.92xa0mmol/L had an approximately 2.8-fold increased risk of macrosomia. Compared with women with serum HDL-C levels above 2.23xa0mmol/L, women with HDL-C levels of less than 1.62xa0mmol/L had a 1.9-fold increased risk of giving birth to an infan with macrosomia. In addition, a higher risk of macrosomia was observed in women with simultaneous hypertriglyceridemia and low serum HDL-C levels (odds ratio [OR] 2.400, 95% confidence interval [CI]: 1.760–3.274) compared to those with hypertriglyceridemia or low serum HDL-C alone (OR 2.074, 95% CI: 1.609–2.673 and OR 1.363, 95% CI: 1.028–1.809, respectively).ConclusionsMaternal serum TG levels and HDL-C levels at late gestation are independent predictors of macrosomia in women without DM.

Clinical and molecular characterization of 5α-reductase type 2 deficiency due to mutations (p.Q6X, p.R246Q) in SRD5A2 gene

Early diagnosis and optimal management for steroid 5α-reductase type 2 deficiency (5α-RD2) patients are major challenges for clinicians and mutation analysis for the 5α-reductase type 2 (SRD5A2) gene is the golden standard for the diagnosis of the disease. In silico analysis of this enzyme has not been reported due to the lack of appropriate model. Moreover, the histological and pathological changes of the gonads are largely unknown. In the present study, a 5α-RD2 patient born with abnormal external genitalia was studied and mutation analysis for SRD5A2 gene was conducted. Moreover, we constructed the homology modeling of 5α-reductase using SWISS-MODEL, followed by the molecular docking study. Furthermore, immunohistochemical staining of Ki67 for the testes tissue was conducted to investigate the potential pathological characteristics. The patient had male (46, XY) chromosomes but presented female characteristics, and the mutation analysis identified a heterozygotes mutation (p.Q6X, p.R246Q) in SRD5A2 gene. In silico analysis elucidated the potential effect of the mutation on enzyme activity. Immunohistochemical staining for the excised testes showed that 30%-50% of the germ cells were Ki67 positive, which indicated the early neoplastic potential. In conclusion, we analyzed the genotype-phenotype correlations of 5α-RD2 caused by a heterozygotes mutation (p.Q6X, p.R246Q). Importantly, we conducted the homology modeling and molecular docking for the first time, which provided a homology model for further investigations. Immunohistochemical results suggested gonadectomy or testis descent should be performed early for 5α-RD2 patient, as delayed treatment would have maintained the testes in a tumorigenic condition.

Expression of FSHR in chondrocytes and the effect of FSH on chondrocytes

OBJECTIVEnChondrocytes express many kinds of hormone receptors. The function of Follicle stimulating hormone (FSH) in the ovary is mediated by FSH receptor (FSHR). FSH receptor (FSHR) is found in many non-ovarian tissues, however it has been unclear if chondrocytes express FSHR. The purpose of this study is to determine it.nnnMETHODSnMouse primary chondrocytes and human articular cartilage tissues were examined. The expression and sequence of FSHR mRNA by reverse transcription polymerase chain reaction (RT-PCR) and sequenced, respectively, and its protein expression was tested using western blotting and location was observed under immunofluorescence microscopy. Ovarian tissue was as a positive control. After FSH stimulated mouse chondrocytes, intracellular cAMP levels were assessed by ELISA, and gene expression relative to Mouse WNT Signaling Pathway was tested by RT2 Profiler PCR Arrays.nnnRESULTSnFSHR was detected at the transcriptional level and confirmed to have the same sequence as that of ovary-derived mRNA of FSHR. FSHR proteins presented at the same line as the positive proteins of ovary, in mouse chondrocytes and human cartilage tissue, respectively. FSHR proteins were located at the cell membrane. Intracellular cAMP contents were significantly elevated up to 7-fold in mouse chondrocytes by forskolin (100xa0mM)xa0(Pxa0<xa00.001); however, different doses of FSH did not change the cAMP contents in mouse primary chondrocytes. RT2 Profiler PCR Arrays demonstrated that FSH could cause changes in gene expression among the 84 preordained genes, such as Fosl1, Rhou, and Dkk1, in mouse chondrocytes relative to the control.nnnCONCLUSIONnMouse chondrocytes and human articular cartilage express functional FSHR. Moreover, FSH can act on chondrocytes and cause genetic changes.

Thyrotropin Alters T Cell Development in the Thymus in Subclinical Hypothyroidism Mouse Model

Subclinical hypothyroidism (SCH) is highly prevalent in the general population and is associated with potential deleterious effects. Although developing T cells express thyroid‐stimulating hormone receptor (TSH‐R), the changes of T cell development in thymus in SCH have not been fully clarified. SCH mouse model, which is characterized by elevated serum TSH but similar thyroid hormone levels, was used to study the role of TSH in T cell development. Thymus weight of SCH mice increased 18% compared with controls. Importantly, the frequencies of CD4+ and CD8+ single‐positive (SP) thymocytes increased 38% and 44%, respectively. We demonstrated that TSH protected thymocytes from apoptosis as evidenced by a significant decrease of Annexin V‐positive thymocytes in SCH mice. Further analysis showed that extracellular‐regulated kinases (ERK) 1/2 in thymus were activated in SCH mice. With analysis of T cell receptor excision circles (TREC), we found that TSH increased recent thymic emigrants (RTE) in spleen tissue in SCH mice. Thus, these results suggest that TSH promoted T cell development and enhanced the thymic recent output in SCH mice, possibly by suppression of apoptosis of thymocytes, indicating that modification of the ERK signalling pathways.

Thyroid stimulating hormone increases hepatic gluconeogenesis via CRTC2

Epidemiological evidence indicates that thyroid stimulating hormone (TSH) is positively correlated with abnormal glucose levels. We previously reported that TSH has direct effects on gluconeogenesis. However, the underlying molecular mechanism remains unclear. In this study, we observed increased fasting blood glucose and glucose production in a mouse model of subclinical hypothyroidism (only elevated TSH levels). TSH acts via the classical cAMP/PKA pathway and CRTC2 regulates glucose homeostasis. Thus, we explore whether CRTC2 is involved in the process of TSH-induced gluconeogenesis. We show that TSH increases CRTC2 expression via the TSHR/cAMP/PKA pathway, which in turn upregulates hepatic gluconeogenic genes. Furthermore, TSH stimulates CRTC2 dephosphorylation and upregulates p-CREB (Ser133) in HepG2 cells. Silencing CRTC2 and CREB decreases the effect of TSH on PEPCK-luciferase, the rate-limiting enzyme of gluconeogenesis. Finally, the deletion of TSHR reduces the levels of the CRTC2:CREB complex in mouse livers. This study demonstrates that TSH activates CRTC2 via the TSHR/cAMP/PKA pathway, leading to the formation of a CRTC2:CREB complex and increases hepatic gluconeogenesis.

Relative variations of gut microbiota in disordered cholesterol metabolism caused by high-cholesterol diet and host genetics

Recent studies performed provide mechanistic insight into effects of the microbiota on cholesterol metabolism, but less focus was given to how cholesterol impacts the gut microbiota. In this study, ApoE−/− Sprague Dawley (SD) rats and their wild‐type counterparts (n = 12) were, respectively, allocated for two dietary condition groups (normal chow and high‐cholesterol diet). Total 16S rDNA of fecal samples were extracted and sequenced by high‐throughput sequencing to determine differences in microbiome composition. Data were collected and performed diversity analysis and phylogenetic analysis. The influence of cholesterol on gut microbiota was discussed by using cholesterol dietary treatment as exogenous cholesterol disorder factor and genetic modification as endogenous metabolic disorder factor. Relative microbial variations were compared to illustrate the causality and correlation of cholesterol and gut microbiota. It turned out comparing to genetically modified rats, exogenous cholesterol intake may play more effective role in changing gut microbiota profile, although the serum cholesterol level of genetically modified rats was even higher. Relative abundance of some representative species showed that the discrepancies due to dietary variation were more obvious, whereas some low abundance species changed because of genetic disorders. Our results partially demonstrated that gut microbiota are relatively more sensitive to dietary variation. Nevertheless, considering the important effect of bacteria in cholesterol metabolism, the influence to gut flora by “genetically caused cholesterol disorder” cannot be overlooked. Manipulation of gut microbiota might be an effective target for preventing cholesterol‐related metabolic disorders.