Loss of CEACAM1 in endothelial cells causes hepatic fibrosis.

OBJECTIVES: Hepatocytic CEACAM1 plays a critical role in NASH pathogenesis, as bolstered by the development of insulin resistance, visceral obesity, steatohepatitis and fibrosis in mice with global Ceacam1 (Cc1) deletion. In contrast, VECadCre+Cc1fl/fl mice with endothelial loss of Cc1 manifested insulin sensitivity with no visceral obesity despite elevated NF-κB signaling and increased systemic inflammation. We herein investigated whether VECadCre+Cc1fl/fl male mice develop hepatic fibrosis and whether this is mediated by increased production of endothelin1 (ET1), a transcriptional NF-κB target. METHODS: VECadCre+Et1.Cc1fl/fl mice with combined endothelial loss of Cc1/Et1 genes were generated. Histological and immunohistochemical analyses were conducted on their livers and on liver tissue biopsies from adult patients undergoing bariatric surgery or from patients with NASH diagnosis receiving liver transplant. RESULTS: Hepatic fibrosis and inflammatory infiltration developed in VECadCre+Cc1fl/fl liver parenchyma. This was preceded by increased ET1 production and reversed with combined endothelial loss of Et1. Conditioned media from VECadCre+Cc1fl/fl, but not VECadCre+Et1.Cc1fl/fl primary liver endothelial cells activated wild-type hepatic stellate cells; a process inhibited by bosentan, an ETAR/ETBR dual antagonist. Consistently, immunohistochemical analysis of liver biopsies from patients with NASH showed a decline in endothelial CEACAM1 in parallel with increased plasma endothelin1 levels and progression of hepatic fibrosis stage. CONCLUSIONS: The data demonstrated that endothelial CEACAM1 plays a key role in preventing hepatic fibrogenesis by reducing autocrine endothelin1 production.

CpG island status as an epigenetic alteration for NIS promoter in thyroid neoplasms; a cross-sectional study with a systematic review.

BACKGROUND: Gene silence via methylation of the CpG islands is cancer's most common epigenetic modification. Given the highly significant role of NIS in thyroid cancer (TC) differentiation, this cross-sectional study aimed to investigate the DNA methylation pattern in seven CpG islands (CpG1-7 including +846, +918, +929, +947, +953, +955, and +963, respectively) of the NIS promoter in patients diagnosed with papillary (PTC), follicular (FTC), and multinodular goiter (MNG). Additionally, a systematic review of the literature was conducted to compare our results with studies concerning methylation of the NIS gene promoter. METHODS: Thyroid specimens from 64 patients met the eligibility criteria, consisting of 28 PTC, 9 FTC, and 27 benign MNG cases. The mRNA of NIS was tested by qRT-PCR. The bisulfite sequencing PCR (BSP) technique was performed to evaluate the promoter methylation pattern of the NIS gene. Sequencing results were received in chromatograph, FASTA, SEQ, and pdf formats and were analyzed using Chromas. The methylation percentage at each position and for each sample was calculated by mC/(mC+C) formula for all examined CpGs; following that, the methylation percentage was also calculated at each CpG site. Besides, a literature search was conducted without restricting publication dates. Nine studies met the eligibility criteria after removing duplicates, unrelated articles, and reviews. RESULTS: NIS mRNA levels decreased in tumoral tissues of PTC (P = 0.04) and FTC (P = 0.03) patients compared to their matched non-tumoral ones. The methylation of NIS promoter was not common in PTC samples, but it was frequent in FTC (P < 0.05). Significant differences were observed in the methylation levels in the 4th(+ 947), 6th(+ 955), and 7th(+ 963) CpGs sites in the forward strand of NIS promoter between FTC and MNG tissues (76.34 ± 3.12 vs 40.43 ± 8.42, P = 0.004, 69.63 ± 3.03 vs 23.29 ± 6.84, P = 0.001 and 50.33 ± 5.65 vs 24 ± 6.89, P = 0.030, respectively). There was no significant correlation between the expression and methylation status of NIS in PTC and FTC tissues. CONCLUSION: Perturbation in NIS promoter's methylation individually may have a potential utility in differentiating MNG and FTC tissues. The absence of a distinct methylation pattern implies the importance of other epigenetic processes, which may alter the production of NIS mRNA. In addition, according to the reversibility of DNA methylation, it is anticipated that the design of particular targeted demethylation medicines will lead to a novel cancer therapeutic strategy.

Regulation of Insulin Clearance by Non-Esterified Fatty Acids.

Insulin stores lipid in adipocytes and prevents lipolysis and the release of non-esterified fatty acids (NEFA). Excessive release of NEFA during sustained energy supply and increase in abdominal adiposity trigger systemic insulin resistance, including in the liver, a major site of insulin clearance. This causes a reduction in insulin clearance as a compensatory mechanism to insulin resistance in obesity. On the other hand, reduced insulin clearance in the liver can cause chronic hyperinsulinemia, followed by downregulation of insulin receptor and insulin resistance. Delineating the cause-effect relationship between reduced insulin clearance and insulin resistance has been complicated by the fact that insulin action and clearance are mechanistically linked to insulin binding to its receptors. This review discusses how NEFA mobilization contributes to the reciprocal relationship between insulin resistance and reduced hepatic insulin clearance, and how this may be implicated in the pathogenesis of non-alcoholic fatty liver disease.

Ovarian expression of follicle stimulating hormone and activin receptors genes in a prenatally-androgenized rat model of polycystic ovary syndrome in adulthood.

BACKGROUND: The expression of genes involved in basic pathways, such as folliculogenesis and steroidogenesis may be affected following prenatal androgen exposure. Besides, exposure to androgens during prenatal life plays a central role in developing polycystic ovary syndrome (PCOS) in females in later life. In the present study, we aimed to examine the expression of the follicle stimulating hormone receptor (FSHR) and activin receptor (actR) genes in ovarian granulosa cells (GCs) of a prenatally-androgenized rat model of PCOS in adulthood. METHODS AND RESULTS: In the adult rat model of PCOS and their controls (n = 8 in each group), different phases of the estrous cycle were determined by vaginal smear. Total RNA was extracted from the ovarian GCs using the TRIzol protocol, a reverse transcription kit was used for complementary DNA (cDNA) synthesis, and the expression of FSHR and actR genes was measured by SYBR-Green Real-Time PCR. GraphPad Prism was used for statistical analysis of data, and the t-Student's test was used to compare the results between the two groups. PCOS rats had longer and irregular estrous cycles compared to controls. The expression of FSHR and actR genes were significantly decreased in the rat model of PCOS compared to control rats. In PCOS rats, genes expression ratios for FSHR and actR were 0.91 ± 0.11 times (P = 0.008) and 0.42 ± 0.13 times (P = 0.048) less than controls, respectively. CONCLUSION: Reduced expression of the FSHR and actR genes in ovarian GCs may be one of the mechanisms mediating PCOS-related disorders, especially abnormal ovarian folliculogenesis and ovulation dysfunction, following exposure to androgens during fetal life.

Insulin sensing by astrocytes is critical for normal thermogenesis and body temperature regulation.

The important role of astrocytes in the central control of energy balance and glucose homeostasis has recently been recognized. Changes in thermoregulation can lead to metabolic dysregulation, but the role of astrocytes in this process is not yet clear. Therefore, we generated mice congenitally lacking insulin receptors (Ir) in astrocytes (IrKOGFAP mice) to investigate the involvement of astrocyte insulin signaling. IrKOGFAP mice displayed significantly lower energy expenditure and a strikingly lower basal and fasting body temperature. When exposed to cold, however, they were able to mount a thermogenic response. IrKOGFAP mice displayed sex differences in metabolic function and thermogenesis that may contribute to the development of obesity and type II diabetes as early as 2 months of age. While brown adipose tissue exhibited higher adipocyte size in both sexes, more apoptosis was seen in IrKOGFAP males. Less innervation and lower BAR3 expression levels were also observed in IrKOGFAP brown adipose tissue. These effects have not been reported in models of astrocyte Ir deletion in adulthood. In contrast, body weight and glucose regulatory defects phenocopied such models. These findings identify a novel role for astrocyte insulin signaling in the development of normal body temperature control and sympathetic activation of BAT. Targeting insulin signaling in astrocytes has the potential to serve as a novel target for increasing energy expenditure.

Hypomethylation of specific CpG sites in the promoter region of steroidogeneic genes (GATA6 and StAR) in prenatally androgenized rats.

INTRODUCTION: The methylation level of promoters is one of the most studied and well-known epigenetic mechanisms that programs the amount of gene expression. Over expression of steroidogenesis genes via epigenetic control can result in hypetandrogenism, which is the main endocrine aspect of polycystic ovarian syndrome (PCOS). AIMS: In the present study we aimed to determine and compare the promoter methylation levels of three steroidogenic genes, CYP17, GATA6 and StAR, in theca cells of prenatally androgenized (PNA) rats to those of controls. MATERIALS AND METHODS: Pregnant Wistar rats in the PNA group received 5 mg free testosterone, dissolved in 500 ml solvent, subcutaneously injected on day 20 of pregnancy, while controls were injected with 500 ml of solvent only. Theca cell samples, taken from the ovaries of eight to ten female offspring of both the PNA and control groups, were measured for promoter methylation levels of the aforementioned genes, using the bisulfite sequence PCR (BSP) method. KEY FINDINGS: Although the promoters of all three genes were slightly hypomethylated in the PNA group, the differences observed were not significant compared to the control group. The methylation of -520 and -822 positions, in the GATA6 and the StAR promoter respectively, were significantly decreased in the PNA group. SIGNIFICANCES: The results of this study suggest that alterations in the steroidogenesis pathway after exposure to excess androgen may be a result of changes in the pattern of the methylation of the relevant genes.

Alteration in follistatin gene expression detected in prenatally androgenized rats.

Impaired ovarian follicle development, the hallmark of polycystic ovarian syndrome (PCOS), is believed to be due to the changes in expression of related genes such as follistatin (FST). Expression of FST gene and methylation level of its promoter in theca cells from adult female rats, prenatally exposed to androgen excess, during different phases of the estrus cycle was determined and compared with controls. Eight pregnant Wistar rats (experimental group) were treated by subcutaneous injection of 5 mg free testosterone on day 20 of pregnancy, while controls (n = 8) received 500 ml solvent. Based on observed vaginal smear, adult female offspring of mothers were divided into three groups. Levels of serum steroidogenic sexual hormones and gonadotropins, expression and promoter methylation of the FST gene were measured using ELISA, cyber-green real-time PCR and bisulfite sequence PCR (BSP), respectively. Compared to controls, the relative expression of FST gene in the treated group decreased overall by 0.85 fold; despite significant changes in different phases, but no significant differences in methylation of FST promoter. Our results reveal that manifestation of PCOS-like phenotype following prenatal exposure to excess androgen is associated with irregularity in expression of the FST gene during the estrus cycle.

Elevated expression of steroidogenesis pathway genes; CYP17, GATA6 and StAR in prenatally androgenized rats.

It is believed that excess androgen exposure of the fetus, via altered gene expression, causes hyperandrogenism a key feature of polycystic ovary syndrome (PCOS). The aim of this study was to evaluate expression of Cytochrome P450-17 (CYP17), GATA-binding protein (GAGT6) and Steroidogenic acute regulatory protein (StAR), genes of adult female rats prenatally exposed to androgen excess, closely reflect endocrine and ovarian disturbances of PCOS in women, by comparing them during different phases of estrus cycle with those of non-treated rats. Both the adult prenatally testosterone exposed and control rats (n=23, each) were divided into four groups based on their observed vaginal smear (proestrus, estrus, metestrus and diestrus) and the relative expression of CYP17, GATA6 and StAR genes was measured in ovarian theca cells using Cyber-green Real-Time PCR. Serum sex steroid hormones and gonadotropins levels were measured using the ELISA method; a comparison of these two groups showed that there was an overall increase in the studied genes (CYP17; 2.39 fold change, 95% CI: 1.23-3.55; P<0.05, GATA6; 2.08 fold change, 95% CI: 1.62-2.55; P<0.0001, and StAR; 1.4 fold change, 95% CI: 1.02-1.78; P<0.05), despite variations in different phases with maximum elevation for all genes in diestrus. The changes observed may impair the normal development of ovaries that mediate the programming of adult PCOS.