Estrogen increases the transcription of human α2-Heremans-Schmid-glycoprotein by an interplay of estrogen receptor α and activator protein-1

A regulatory mechanism of mouse kallikrein 1 gene expression by estrogen

Tissue kallikrein 1 (Klk1) is a serine protease that degrades several proteins including insulin-like growth factor binding protein-3 and extracellular matrix molecules. Klk1 mRNA expression in the mouse uterus was increased by estradiol-17β (E2). The present study aimed to clarify the regulatory mechanism for Klk1 expression by estrogen. The promoter analysis of the 5'-flanking region of Klk1 showed that the minimal promoter of Klk1 existed in the -136/+24 region, and the estrogen-responsive region in the -433/-136 region. Tamoxifen increased Klk1 mRNA expression and the promoter activity, suggesting the involvement of AP-1 sites. Site-directed mutagenesis for the putative AP-1 sites in the -433/-136 region showed that the two putative AP-1 sites were involved in the regulation of Klk1 expression. Binding of estrogen receptor α (ERα) to the -433/-136 region was revealed by Chip assay. These results indicated that ERα bound the two putative AP-1 sites and transactivated Klk1 in the mouse uterus.

AMP activated kinase negatively regulates hepatic Fetuin-A via p38 MAPK-C/EBPβ/E3 Ubiquitin Ligase Signaling pathway

Fetuin-A (Fet-A) is a liver-secreted phosphorylated protein, known to impair insulin signaling, which has been shown to be associated with obesity, insulin resistance, and incident diabetes. Fet-A interacts with the insulin-stimulated insulin receptor (IR) and inhibits IR tyrosine kinase activity and glucose uptake. It has been shown that high glucose increases Fet-A expression through the ERK1/2 signaling pathway. However, factors that downregulate Fet-A expression and their potential mechanisms are unclear. We examined the effect of AMP-activated protein kinase (AMPK) on high-glucose induced Fet-A expression in HepG2 cells, Hep3B cells and primary rat hepatocytes. High glucose increased Fet-A and phosphorylated (Ser312) fetuin-A (pFet-A) expression, which are known to impair insulin signaling. AICAR-induced AMPK activation significantly down-regulated high glucose-induced Fet-A expression and secretion of pFet-A while treatment with Compound C (AMPK inhibitor), SB202190 (p38 MAPK inhibitor) or p38 MAPK siRNA transfection prevented AICAR-induced downregulation of Fet-A expression. In addition, activation of p38 MAPK, by anisomycin, decreased the hepatic expression of Fet-A. Further, we our studies have shown that short-term effect of AICAR-treatment on Fet-A expression was mediated by proteosomal degradation, and long-term treatment of AICAR was associated with decrease in hepatic expression of C/EBP beta, an important transcription factor involved in the regulation of Fet-A. Taken together, our studies implicate a critical role for AMPK-p38 MAPK-C/EBPb-ubiquitin-proteosomal axis in the regulation of the expression of hepatic Fet-A.

Opposite estrogen effects of estrone and 2-hydroxyestrone on MCF-7 sensitivity to the cytotoxic action of cell growth, oxidative stress and inflammation activity

There are many kinds of estrogens, and endogenous estrogens produce a variety of estrogen metabolites with similar structure but with different physiological effects after metabolism in vivo. Studies have shown that estrone (E1) widely occurs in the environment and animal-derived food. Because of its estrogen effect, E1 can have adverse effects on the human body as an endocrine disruptor. In this study, we found that E1 and 2-hydroxyestrone (2-OH-E1), the hydroxylation metabolite of estrogen, have opposite proliferative effects on breast cancer cells (MCF-7) through cell proliferation experiments and comparison of their effects by molecular docking and detection of ROS, Ca²⁺, and cell pathway proteins. The effects of 2-methoxyestrone (2-MeO-E1) and 16α-hydroxyestrone (16α-OH-E1) on the biochemical and protein levels of MCF-7 were further studied to compare the effects of metabolic sites and modes on estrogen effects. Hydroxylation of E1 at the C2 site weakened the estrogen effect, down-regulated the expression of the mammalian target of rapamycin (mTOR) and protein kinase B (Akt) pathway proteins, inhibited the proliferation of cancer cells, and enhanced anti-oxidative stress and anti-inflammation. Methoxylation at the C2 position also inhibited the expression of inflammatory and oxidative stress pathway proteins but did not greatly affect the estrogen effects. However, hydroxylation on C16 had no significant effect on the biological effects of estrogen. Therefore, the structural changes of estrogen on C2 are important reasons for the different physiological effects of estrogen and its metabolites. Thus, by regulating the gene Cytochrome P450 1B1(CYP1B1), which affects the hydroxylation metabolism of estrogen, and promoting the hydroxylation of estrone at the C2 position, the estrogen effect of estrone can be effectively reduced, thus reducing the harm its poses in food and the environment.

SkeletalVis: an exploration and meta-analysis data portal of cross-species skeletal transcriptomics data

MOTIVATION

Skeletal diseases are prevalent in society, but improved molecular understanding is required to formulate new therapeutic strategies. Large and increasing quantities of available skeletal transcriptomics experiments give the potential for mechanistic insight of both fundamental skeletal biology and skeletal disease. However, no current repository provides access to processed, readily interpretable analysis of this data. To address this, we have developed SkeletalVis, an exploration portal for skeletal gene expression experiments.

RESULTS

The SkeletalVis data portal provides an exploration and comparison platform for analysed skeletal transcriptomics data. It currently hosts 287 analysed experiments with 739 perturbation responses with comprehensive downstream analysis. We demonstrate its utility in identifying both known and novel relationships between skeletal expression signatures. SkeletalVis provides users with a platform to explore the wealth of available expression data, develop consensus signatures and the ability to compare gene signatures from new experiments to the analysed data to facilitate meta-analysis.

AVAILABILITY AND IMPLEMENTATION

The SkeletalVis data portal is freely accessible at http://phenome.manchester.ac.uk.

SUPPLEMENTARY INFORMATION

Supplementary data are available at Bioinformatics online.

Regulation of fetuin A gene expression in the neonatal pig liver

Fetuin A (also known as α2-Heremans-Schmid glycoprotein) is a protein primarily expressed by the liver and secreted into the blood. Previous studies have suggested that plasma concentrations of fetuin A are elevated with impaired growth rate in swine. The present study was designed to examine the relationship of porcine fetuin A with growth rate in the pig and to also elucidate the regulation of fetuin A expression by examining the hormonal and cytokine regulation of fetuin A mRNA abundance in hepatocytes prepared from suckling piglets. Quantitative real-time PCR assay was used to quantify the number of fetuin A mRNA molecules/molecule cyclophilin mRNA. Total RNA was isolated from liver of three different groups of pigs to assess changes in mRNA abundance of fetuin A: normal piglets at day 1, day 7 day 21 or 6 months of age (n=6 for each age); runt and control piglets at day 1 of age (n=4); slow growing and normal growing piglets at 21 days of age (n=8). Following birth, fetuin A gene expression increased from day 1 and 7 of age (P<0.05), and then declined at 21 days of age (P<0.05), with a much greater decline to 6 months of age (P<0.01). Fetuin A mRNA abundance was higher in runt pigs v. their normal birth weight littermates (P<0.05). Similarly, fetuin A gene expression was higher in livers of pigs that were born at a normal weight but that grew much slower than littermates with the same birth weight (P<0.05). Hepatocytes were isolated from preweaned piglets and maintained in serum-free monolayer culture for up to 72 h to permit examination of the influences of hormones, cytokines and redox modifiers on fetuin A mRNA abundance. Fetuin A gene expression was enhanced by glucagon, T3 and resveratrol (P<0.05). Growth hormone, cytokines (interleukin6, tumor necrosis factor-α) and antioxidants (N-acetylcysteine, quercertin) reduced fetuin A mRNA abundance (P<0.05). A role for fetuin A in postnatal development is suggested by the differences in fetuin A mRNA abundance between runt piglets or slow growing piglets and their normal growing sized littermates. The hepatocyte experiments suggest multiple hormones and cytokines may contribute to the regulation of fetuin A during early growth of the pig.

Detection of genetic loci associated with plasma fetuin-A: a meta-analysis of genome-wide association studies from the CHARGE Consortium

Plasma fetuin-A is associated with type 2 diabetes, and AHSG, the gene encoding fetuin-A, has been identified as a susceptibility locus for diabetes and metabolic syndrome. Thus far, unbiased investigations of the genetic determinants of plasma fetuin-A concentrations have not been conducted. We searched for single nucleotide polymorphisms (SNPs) related to fetuin-A concentrations by a genome-wide association study in six population-based studies. We examined the association of fetuin-A levels with ∼ 2.5 million genotyped and imputed SNPs in 9,055 participants of European descent and 2,119 African Americans. In both ethnicities, the strongest associations were centered in a region with a high degree of LD near the AHSG locus. Among 136 genome-wide significant (P < 0.05 × 10-8) SNPs near the AHSG locus, the top SNP was rs4917 (P =1.27 × 10-303), a known coding SNP in exon 6 that is associated with a 0.06 g/l (∼13%) lower fetuin-A level. This variant alone explained 14% of the variation in fetuin-A levels. Analyses conditioned on rs4917 indicated that the strong association with the AHSG locus stems from additional independent associations of multiple variants among European Americans. In conclusion, levels of fetuin-A in plasma are strongly associated with SNPs in its encoding gene, AHSG, but not elsewhere in the genome. Given the strength of the associations observed for multiple independent SNPs, the AHSG gene is an example of a candidate locus suitable for additional investigations including fine mapping to elucidate the biological basis of the findings and further functional experiments to clarify AHSG as a potential therapeutic target.