CpG island reconfiguration for the establishment and synchronization of polycomb functions upon exit from naive pluripotency.

Polycomb group (PcG) proteins are essential for post-implantation development by depositing repressive histone modifications at promoters, mainly CpG islands (CGIs), of developmental regulator genes. However, promoter PcG marks are erased after fertilization and de novo established in peri-implantation embryos, coinciding with the transition from naive to primed pluripotency. Nevertheless, the molecular basis for this establishment remains unknown. In this study, we show that the expression of the long KDM2B isoform (KDM2BLF), which contains the demethylase domain, is specifically induced at peri-implantation and that its H3K36me2 demethylase activity is required for PcG enrichment at CGIs. Moreover, KDM2BLF interacts with BRG1/BRM-associated factor (BAF) and stabilizes BAF occupancy at CGIs for subsequent gain of accessibility, which precedes PcG enrichment. Consistently, KDM2BLF inactivation results in significantly delayed post-implantation development. In summary, our data unveil dynamic chromatin configuration of CGIs during exit from naive pluripotency and provide a conceptual framework for the spatiotemporal establishment of PcG functions.

Antibody-free profiling of transcription factor occupancy during early embryogenesis by FitCUT&RUN.

Key transcription factors (TFs) play critical roles in zygotic genome activation (ZGA) during early embryogenesis, whereas genome-wide occupancies of only a few factors have been profiled during ZGA due to the limitation of cell numbers or the lack of high-quality antibodies. Here, we present FitCUT&RUN, a modified CUT&RUN method, in which an Fc fragment of immunoglobulin G is used for tagging, to profile TF occupancy in an antibody-free manner and demonstrate its reliability and robustness using as few as 5000 K562 cells. We applied FitCUT&RUN to zebrafish undergoing embryogenesis to generate reliable occupancy profiles of three known activators of zebrafish ZGA: Nanog, Pou5f3, and Sox19b. By profiling the time-series occupancy of Nanog during zebrafish ZGA, we observed a clear trend toward a gradual increase in Nanog occupancy and found that Nanog occupancy prior to the major phase of ZGA is important for the activation of some early transcribed genes.

Integration of ATAC-Seq and RNA-Seq reveals FOSL2 drives human liver progenitor-like cell aging by regulating inflammatory factors.

BACKGROUND: Human primary hepatocytes (PHCs) are considered to be the best cell source for cell-based therapies for the treatment of end-stage liver disease and acute liver failure. To obtain sufficient and high-quality functional human hepatocytes, we have established a strategy to dedifferentiate human PHCs into expandable hepatocyte-derived liver progenitor-like cells (HepLPCs) through in vitro chemical reprogramming. However, the reduced proliferative capacity of HepLPCs after long-term culture still limits their utility. Therefore, in this study, we attempted to explore the potential mechanism related to the proliferative ability of HepLPCs in vitro culture. RESULTS: In this study, analysis of assay for transposase accessible chromatin using sequencing (ATAC-seq) and RNA sequencing (RNA-seq) were performed for PHCs, proliferative HepLPCs (pro-HepLPCs) and late-passage HepLPCs (lp-HepLPCs). Genome-wide transcriptional and chromatin accessibility changes during the conversion and long-term culture of HepLPCs were studied. We found that lp-HepLPCs exhibited an aged phenotype characterized by the activation of inflammatory factors. Epigenetic changes were found to be consistent with our gene expression findings, with promoter and distal regions of many inflammatory-related genes showing increased accessibility in the lp-HepLPCs. FOSL2, a member of the AP-1 family, was found to be highly enriched in the distal regions with increased accessibility in lp-HepLPCs. Its depletion attenuated the expression of aging- and senescence-associated secretory phenotype (SASP)-related genes and resulted in a partial improvement of the aging phenotype in lp-HepLPCs. CONCLUSIONS: FOSL2 may drive the aging of HepLPCs by regulating inflammatory factors and its depletion may attenuate this phenotypic shift. This study provides a novel and promising approach for the long-term in vitro culture of HepLPCs.

Integrated analysis of miRNAs and mRNA profiling reveals the potential roles of miRNAs in sheep hair follicle development.

BACKGROUND: Merino sheep exhibit high wool production and excellent wool quality. The fleece of Merino sheep is predominantly composed of wool fibers grown from hair follicles (HFs). The HF is a complex biological system involved in a dynamic process governed by gene regulation, and gene expression is regulated by microRNAs (miRNAs). miRNA inhibits posttranscriptional gene expression by specifically binding to target messenger RNA (mRNA) and plays an important role in regulating gene expression, the cell cycle and biological development sequences. The purpose of this study was to examine mRNA and miRNA binding to identify key miRNAs and target genes related to HF development. This will provide new and important insights into fundamental mechanisms that regulate cellular activity and cell fate decisions within and outside of the skin. RESULTS: We analyzed miRNA data in skin tissues collected from 18 Merino sheep on four embryonic days (E65, E85, E105 and E135) and two postnatal days (D7 and D30) and identified 87 differentially expressed miRNAs (DE-miRNAs). These six stages were further divided into two longer developmental stages based on heatmap cluster analysis, and the results showed that DE-mRNAs in Stage A were closely related to HF morphogenesis. A coanalysis of Stage A DE-mRNAs and DE-miRNAs revealed that 9 DE-miRNAs and 17 DE-mRNAs presented targeting relationships in Stage A. We found that miR-23b and miR-133 could target and regulate ACVR1B and WNT10A. In dermal fibroblasts, the overexpression of miR-133 significantly reduced the mRNA and protein expression levels of ACVR1B. The overexpression of miR-23b significantly reduced the mRNA and protein expression levels of WNT10A. CONCLUSION: This study provides a new reference for understanding the molecular basis of HF development and lays a foundation for further improving sheep HF breeding. miRNAs and target genes related to hair follicular development were found, which provided a theoretical basis for molecular breeding for the culture of fine-wool sheep.

Effect of the FA2H Gene on cashmere fineness of Jiangnan cashmere goats based on transcriptome sequencing.

BACKGROUND: Cashmere goats are a heterogeneous hairy mammal. The fineness of cashmere can affect its economic value. Therefore, in this study, we used transcriptome sequencing techniques to analyze the gene expression profiles of the skin tissues of cashmere goats with different cashmere fineness. The selected candidate genes were functionally verified with the secondary hair follicle hair papillary cells of cashmere goats. RESULTS: We identified 479 DEGs, of which 238 mRNAs were up-regulated in the fine velvet group and 241 mRNA were down-regulated. Based on functional annotation and protein interaction network analysis, we found some genes that may affect the fineness of cashmere, including SOX18, SOX4, WNT5A, IGFBP4, KAP8, KRT36, and FA2H. Using qRT-PCR, Western blot, CCK-8 cell viability detection, EDU cell proliferation detection, and flow cytometry, we found that overexpression of the FA2H gene could promote the proliferation of secondary hair follicle DPCs in cashmere goats. At the same time, we proved that FA2H could regulate the expression levels of the FGF5 and BMP2 genes in DPCs. CONCLUSION: The results of this study provide a useful reference for the genetics and breeding of Jiangnan cashmere goats and goat genome annotation, and provide an experimental basis for improving cashmere quality of the cashmere goat.

Gene network analysis reveals candidate genes related with the hair follicle development in sheep.

BACKGROUND: Merino sheep are the most famous fine wool sheep in the world. They have high wool production and excellent wool quality and have attracted worldwide attention. The fleece of the Merino sheep is composed predominantly of wool fibers grown from secondary wool follicles. Therefore, it is necessary to study the development of hair follicles to understand the mechanism of wool production. The hair follicle is a complex biological system involved in a dynamic process governed by gene regulation. The hair follicle development process is very complex and poorly understood. The purpose of our research is to identify candidate genes related to hair follicle development, provide a theoretical molecular breeding basis for the cultivation of fine wool sheep, and provide a reference for the problems of hair loss and alopecia areata that affect human beings. RESULTS: We analyzed mRNAs data in skin tissues of 18 Merino sheep at four embryonic days (E65, E85, E105 and E135) and two postnatal days (P7 and P30). G1 to G6 represent hair follicles developmental at six stages (i.e. E65 to P30). We identified 7879 differentially expressed genes (DEGs) and 12623 novel DEGs, revealed different expression patterns of these DEGs at six stages of hair follicle development, and demonstrated their complex interactions. DEGs with stage-specific expression were significantly enriched in epidermal differentiation and development, hair follicle development and hair follicle morphogenesis and were enriched in many pathways related to hair follicle development. The key genes (LAMA5, WNT10A, KRT25, SOSTDC1, ZDHHC21, FZD1, BMP7, LRP4, TGFß2, TMEM79, SOX10, ITGB4, KRT14, ITGA6, and GLI2) affecting hair follicle morphogenesis were identified by network analysis. CONCLUSION: This study provides a new reference for the molecular basis of hair follicle development and lays a foundation for further improving sheep hair follicle breeding. Candidate genes related to hair follicular development were found, which provided a theoretical basis for molecular breeding for the culture of fine wool sheep. These results are a valuable resource for biological investigations of fleece evolution in animals.

Gallic acid as a key substance to inhibit proliferation and adipogenesis in bovine subcutaneous adipocyte.

Gallic acid (GA) is a widespread naturally occurring phenolic acid and one of the main active monomers that forms polyphenols such as tannins. In recent years, GA has been found as a potential regulator in lipid metabolism. However, effects and possible mechanisms of GA on cell growth and lipid metabolism of bovine subcutaneous adipocytes remain unknown. In this study, we investigated whether GA could affect proliferation and adipogenesis of subcutaneous adipocyte in beef cattle. We found that GA possesses inhibitive effects on proliferation and adipogenesis of bovine subcutaneous adipocyte via activating the metabolic master factor AMP-activated protein kinase alpha (AMPKα) to promote programmed cell death and lipolysis. The findings prove GA is a key substance to inhibit proliferation and adipogenesis of bovine subcutaneous adipocyte in vitro. Further in vivo study needs conducted to verify the reductive effects of GA on subcutaneous fat in beef cattle.

NUCOME: A comprehensive database of nucleosome organization referenced landscapes in mammalian genomes.

BACKGROUND: Nucleosome organization is involved in many regulatory activities in various organisms. However, studies integrating nucleosome organization in mammalian genomes are very limited mainly due to the lack of comprehensive data quality control (QC) assessment and uneven data quality of public data sets. RESULTS: The NUCOME is a database focused on filtering qualified nucleosome organization referenced landscapes covering various cell types in human and mouse based on QC metrics. The filtering strategy guarantees the quality of nucleosome organization referenced landscapes and exempts users from redundant data set selection and processing. The NUCOME database provides standardized, qualified data source and informative nucleosome organization features at a whole-genome scale and on the level of individual loci. CONCLUSIONS: The NUCOME provides valuable data resources for integrative analyses focus on nucleosome organization. The NUCOME is freely available at http://compbio-zhanglab.org/NUCOME .

GLEANER: a web server for GermLine cycle Expression ANalysis and Epigenetic Roadmap visualization.

BACKGROUND: Germline cells are important carriers of genetic and epigenetic information transmitted across generations in mammals. During the mammalian germline cell development cycle (i.e., the germline cycle), cell potency changes cyclically, accompanied by dynamic transcriptional changes and epigenetic reprogramming. Recently, to understand these dynamic and regulatory mechanisms, multiomic analyses, including transcriptomic and epigenomic analyses of DNA methylation, chromatin accessibility and histone modifications of germline cells, have been performed for different stages in human and mouse germline cycles. However, the long time span of the germline cycle and material scarcity of germline cells have largely limited the understanding of these dynamic characteristic changes. A tool that integrates the existing multiomics data and visualizes the overall continuous dynamic trends in the germline cycle can partially overcome such limitations. RESULTS: Here, we present GLEANER, a web server for GermLine cycle Expression ANalysis and Epigenetics Roadmap visualization. GLEANER provides a comprehensive collection of the transcriptome, DNA methylome, chromatin accessibility, and H3K4me3, H3K27me3, and H3K9me3 histone modification characteristics in human and mouse germline cycles. For each input gene, GLEANER shows the integrative analysis results of its transcriptional and epigenetic features, the genes with correlated transcriptional changes, and the overall continuous dynamic trends in the germline cycle. We further used two case studies to demonstrate the detailed functionality of GLEANER and highlighted that it can provide valuable clues to the epigenetic regulation mechanisms in the genetic and epigenetic information transmitted during the germline cycle. CONCLUSIONS: To the best of our knowledge, GLEANER is the first web server dedicated to the analysis and visualization of multiomics data related to the mammalian germline cycle. GLEANER is freely available at http://compbio-zhanglab.org/GLEANER .

Inherited DNA methylation primes the establishment of accessible chromatin during genome activation.

For animals, epigenetic modifications can be globally or partially inherited from gametes after fertilization, and such information is required for proper transcriptional regulation, especially during the process of zygotic genome activation (ZGA). However, the mechanism underlying how the inherited epigenetic signatures affect transcriptional regulation during ZGA remains poorly understood. Here, we performed genome-wide profiling of chromatin accessibility during zebrafish ZGA, which is closely related to zygotic transcriptional regulation. We observed a clear trend toward a gradual increase in accessible chromatin during ZGA. Furthermore, accessible chromatin at the promoters displayed a sequential priority of emergence, and the locations of the accessible chromatin were precisely primed by the enrichment of unmethylated CpGs that were fully inherited from gametes. On the other hand, distal regions with high methylation levels that were inherited from the sperm facilitated the binding of DNA methylation-preferred transcription factors, such as Pou5f3 and Nanog, which contributed to the establishment of accessible chromatin at these loci. Our results demonstrate a model whereby inherited DNA methylation signatures from gametes prime the establishment of accessible chromatin during zebrafish ZGA through two distinct mechanisms.

Caffeic acid modulates methane production and rumen fermentation in an opposite way with high-forage or high-concentrate substrate in vitro.

BACKGROUND: Plant secondary metabolites, including tannins, saponins and phenolic acids, possess potential methane (CH4 ) inhibition bioactivity. Caffeic acid (CA), as one of the typical phenolic acids, serves as a promising rumen CH4 inhibitor, but the underlying mechanisms and investigations with typical formulated rations are still not well documented. Therefore, a batch culture study was conducted to investigate the effects of CA on methanogenesis, rumen fermentation and growth of ruminal microorganisms when high-forage or high-concentrate substrates are fermented. RESULTS: After 48 h incubations, adding CA up to 40 g kg-1 dry matter linearly reduced (P < 0.05) the disappearance of dry matter, neutral detergent fiber (NDFD), total gas, methanogenesis, total volatile fatty acid and 16S rDNA copy numbers of Ruminococcus albus and Butyrivibrio fibrisolvens, and increased 16S rDNA copy numbers of methanogens for the high-forage treatment. For the high-concentrate treatment, CA exerted opposite effects (P < 0.05) on the above variables, except that CA did not affect (P > 0.05)16S rDNA copy numbers of methanogens or R. albus. CONCLUSION: Caffeic acid inhibited in vitro methanogenesis and rumen fermentation with high-forage substrate incubation. Contrarily, CA benefited in vitro fermentation and enhanced methanogenesis with high-concentrate substrate incubation. It suggests that CA modulates methanogenesis and rumen fermentation mainly by affecting the growth of cellulolytic bacteria in vitro. © 2020 Society of Chemical Industry.

Protective effects of astaxanthin on lipopolysaccharide-induced inflammation in bovine endometrial epithelial cells†.

Astaxanthin (AST), a natural antioxidant carotenoid, has been shown to exert anti-inflammatory effects. However, to our knowledge, no study has specifically addressed the potential protective effects of AST against bovine endometritis. The purpose of this study was to examine whether treatment with AST could protect endometrial epithelial cells against lipopolysaccharide (LPS)-induced inflammatory injury. Treatment of bovine endometrial (BEND) epithelial cell line with AST reduced LPS-induced production of interleukin-6 and tumor necrosis factor-alpha, increased the cellular activity of superoxide dismutase and catalase, decreased the proportion of apoptotic cells, and promoted the production of insulin-like growth factor and epithelial growth factor. The effects of AST were mediated through the downregulation of B-cell lymphoma 2 (Bcl-2) associated X, apoptosis regulator (Bax), and cleaved caspase-3 and through the upregulation of Bcl-2. Moreover, AST significantly increased the expression of the tight junction proteins (TJP) claudin, cadherin-1, and TJP1, which play an essential role in the maintenance of host endometrial defense barrier against pathogen infection. Collectively, these results demonstrated that treatment with AST protected against oxidative stress, prevented cell apoptosis, promoted BEND cells viability, and increased the production of growth factors, in addition to activating the endometrial defense barrier. Therefore, AST is a promising therapeutic agent for the prevention and treatment of endometritis. This finding is of utmost importance in the present times when the excessive use of antibiotics has resulted in the development of antibiotic-resistant bacteria.

Prediction of Serum-Free and Cerebrospinal Fluid Valproic Acid Levels in Patients With Hypoalbuminemia After Craniotomy.

BACKGROUND: In patients with hypoalbuminemia after craniotomy, total serum concentrations of valproic acid (VPA) may provide poor clinical insights, owing to saturated protein binding and increased unbound fractions. However, very few clinical laboratories routinely analyze free concentrations of the drug. The aim of this study was to develop a model to predict serum-free and cerebrospinal fluid (CSF) levels of VPA based on its total concentration and to investigate the model's applicability. METHODS: Total serum and CSF concentrations of VPA in 79 patients were measured using a validated immunoassay between January 2015 and December 2015. The demographic, clinical, and laboratory information of patients were retrieved from medical records. A multiple linear regression analysis was adopted to determine the potential variations and establish the functional relationship between CSF concentration and significant clinical factors. RESULTS: Based on the stepwise multiple linear regression analysis performed using the natural logarithm of the concentration of VPA in the CSF as the dependent variable, serum concentrations of VPA (X1, ß' = 0.844), serum albumin concentration (X2, ß' = -0.393), and CSF protein concentration (X3, ß' = 0.098) were identified as the 3 variables that significantly predicted the dependent variable: (Equation is included in full-text article.), with a coefficient of determination (R) of 0.874. As the CSF protein level is often unavailable, the model was redefined to include 2 variables-serum concentrations of VPA (X1, ß' = 0.840) and serum albumin concentration (X2, ß' = -0.359): (Equation is included in full-text article.), with R = 0.813. CONCLUSIONS: Based on total VPA and serum albumin concentrations, we developed a model to predict serum-free and CSF levels of VPA. This model is useful for correcting dose adjustment in patients with hypoalbuminemia after craniotomy.

Effect of simvastatin on bovine intramuscular and subcutaneous adipocytes proliferation and gene expression in vitro.

Simvastatin (SIM) is a widely used anticholesterolemic drug that blocks the biosynthesis of cholesterol. However, SIM also has pleiotropic effects on 3-hydroxy-3-methyglutary-CoA reductase (HMGR), cholesteryl ester transfer protein (CETP), and lipoprotein lipase (LPL), which are important genes in the cholesterol biosynthesis and transport processes. We investigated the effects of different concentrations of SIM on the mRNA expression of these genes in bovine intramuscular and subcutaneous adipocytes from the longissimus dorsi muscle and subcutaneous fat tissues of Luxi Yellow cattle. The results showed that SIM treatment showed dose-dependent toxicity on normal adipose cells, but no effect on cell proliferation. SIM decreased HMGR expression in a dose-dependent manner but showed no significant effect on CETP and LPL expression. Thus, SIM may lower the cholesterol content by decreasing the HMGR expression level, but CETP and LPL may be regulated through other mechanisms, which require further investigation.

Comparison of apoptosis between bovine subcutaneous and intramuscular adipocytes by resveratrol via SIRT1.

A better understanding of the differential mechanisms regulating the deposition and release of fat between intramuscular and external adipose tissues is very important to the quality of beef. Resveratrol is a natural activator of sirtuin type 1 (SIRT1), a NAD-dependent deacetylase involved in regulating the cell cycle, energy homeostasis and apoptosis in adipose tissue. To compare the molecular mechanisms underlying differential apoptosis in bovine intramuscular and subcutaneous adipocytes, we evaluated the effect of resveratrol on differentiated adipocytes. We found that resveratrol-induced apoptosis in bovine adipocytes by regulating SIRT1 activity. In addition, we report that bovine intramuscular and subcutaneous adipocytes exhibited differential responses to resveratrol. In particular, gene and protein expression of Bcl-2 was higher, whereas that of SIRT1, AMPKα, FOXO1, Bax and caspase-3 were lower in bovine subcutaneous adipocytes than in intramuscular adipocytes. After resveratrol-treatment, the extent of up- or down-regulation was higher in subcutaneous adipocytes than in intramuscular adipocytes. These data indicate that bovine subcutaneous adipocytes are more sensitive to apoptosis than intramuscular adipocytes following treatment with resveratrol by regulating SIRT1 activity.

In vitro degradability of corn silage and Leymus chinensis silage and evaluation of their mixed ratios on performance, digestion and serum parameters in beef cattle.

This study investigated the degradability of corn silage (CS) and Leymus chinensis silage (LS) in vitro, and evaluated the effect of various ratios on growth performance, digestion and serum parameters in beef cattle. A 72-hr bath culture trial was performed to evaluate degradability and rumen fermentation characteristics of CS, LS and their combinations [67:33, 33:67, dry matter (DM) basis]. Forty Simmental steers, averaging 441.46 ± 4.45 kg of body weight (BW), were randomly allocated into four dietary treatments for 120-d period. Diets were given as total mixed rations with a forage-to-concentrate ratio of 60:40 and CS:LS ratios of 100:0, 67:33, 33:67 and 0:100 (DM basis). The in vitro trial showed that DM and neutral detergent fibre (NDF) degradability decreased linearly as LS proportion increased, whereas CP degradability increased linearly. Additionally, increased acid detergent fibre (ADF) degradability was detected at 48 hr of incubation. Increasing the proportion of LS increased rumen liquor pH and decreased volatile fatty acid linearly including acetate, propionate and butyrate, whereas the ammonia-N increased linearly at 12 and 72 hr of incubation. With increasing LS ratio, final BW, average daily gain and feed conversion ratio of steers decreased linearly, whereas DMI was not affected. Additionally, apparent digestibility of DM, organic matter, NDF and ADF linearly and quadratically decreased while ether extract apparent digestibility decreased linearly, and CP apparent digestibility was not affected. Serum glucose and urea nitrogen linearly and quadratically decreased while glutamic-pyruvic transaminase activity linearly decreased as the proportion of LS increased. Other serum parameters including total triglycerides, total cholesterol, total protein, albumin and glutamic-oxalacetic transaminease were not affected. Overall, enhancing ratio of LS caused inferior DM and NDF degradability but improved CP degradability in the combinations of LS and CS. A CS:LS ratio of 67:33 resulted in the best growth performance and nutrient utilization in steers.

Alanyl-glutamine ameliorates lipopolysaccharide-induced inflammation and barrier function injury in bovine jejunum epithelial cells.

The aim of this study was to investigate the effects of alanyl-glutamine (Ala-Gln) on the regulation of lipopolysaccharide (LPS)-induced inflammation and barrier function in bovine jejunum epithelial cells (BJECs). BJECs were exposed (or not) to 1 µg/mL LPS for 24 h to generate a pro-inflammatory model. The cells were then treated with different concentrations of Ala-Gln (0.25, 0.5, 1.0, 2.0, or 4.0 mmol/L) to detect any regulatory effects on the inflammation and barrier function of BJECs. LPS decreased cell viability and enhanced the production of the pro-inflammatory cytokines interleukin (IL)-6 and IL-8. LPS induced inflammation and damaged the barrier function of BJECs, as evidenced by up-regulated mRNA and protein expression of inflammatory factors and down-regulated expression of tight junction proteins. Conversely, Ala-Gln rescued the decrease in cell viability and prevented the accumulation of ILs after LPS exposure by reducing the mRNA and protein expression levels of inflammatory factors. In addition, Ala-Gln induced the mRNA and protein expression of multiple tight junction proteins, and thus reconstituted the barrier function of BJECs. In conclusion, Ala-Gln attenuates injury from inflammation and repairs damaged intestinal barrier induced with LPS, suggesting its potential as a therapeutic agent against intestinal inflammation in mammals.

Resveratrol induces apoptosis and inhibits adipogenesis by stimulating the SIRT1-AMPKα-FOXO1 signalling pathway in bovine intramuscular adipocytes.

Sirtuin type 1 (SIRTl) and AMP-activated protein kinase (AMPK) play important roles in regulating energy metabolism, cell proliferation and differentiation, ageing, apoptosis, and metabolism. The effect of 100, 200, and 400 µm Resveratrol (RES), an activator of SIRT1, on apoptosis of bovine intramuscular adipocytes was investigated by nuclear staining, flow cytometry, quantitative real-time polymerase chain reaction, and western blotting. Results show that RES inhibited adipogenesis, decreased cell viability, and increased apoptotic rates in a dose-dependent way. RES up-regulated SIRT1, AMPKα, forkhead box O1 (FOXO1), hormone-sensitive lipase (HSL), lipoprotein lipase (LPL), caspase-3, and Bax; and down-regulated peroxisome proliferator-activated receptor-gamma (PPARγ), fatty acid synthase (FAS), and Bcl-2, at both mRNA and protein level. The effect of RES was abolished by addition of sirtinol (an inhibitor of SIRT1). This is the first study demonstrating a role for AMPK-SIRT1-FOXO1 signalling pathway in regulating apoptosis in bovine intramuscular adipocytes. Our findings provide important information on the mechanism by which RES controls deposition of cattle intramuscular fat via adipocyte apoptosis.

C/EBPα negatively regulates SIRT7 expression via recruiting HDAC3 to the upstream-promoter of hepatocellular carcinoma cells.

Mammalian Sirtuin proteins (SIRTs) are homologs of yeast Sir2, and characterized as class III histone deacetylases of NAD(+) dependence. Unlike their lower counterparts that are directly involved in the extending of lifespan, mammalian SIRTs mainly function in metabolism and cellular homeostasis, among them, SIRT7 is the least understood. SIRT7 is localized in the nucleus and rich in nucleoli associated with RNA polymerase I, and correlated with cell proliferation. In contrast, SIRT7 has recently been demonstrated to specifically deacetylate H3K18ac in the chromatin, and in most cases represses proliferation. Although MicroRNA as miR-125b has been reported to down-regulate SIRT7 by binding to its 3'UTR, however, how SIRT7 gene is regulated remains unclear. Here, we identified the transcription initiation site of human SIRT7 gene at the upstream 23rd A nucleotide respective to the translational codon, and the SIRT7 is a TATA-less and initiator-less gene. The sequences in the upstream region between -256 and -129 bp are identical with important functions in the three species detected. A C/EBPα responding element is found that binds both C/EBPα and C/EBPß in vitro. We showed TSA induced SIRT7 gene transcription and only the HDAC3, but not its catalytic domain depleted mutant, interacted with C/EBPα to occupy the C/EBPα element and repressed SIRT7 gene in the hepatocellular carcinoma cells. To our knowledge, this is the first report on the regulation mechanism of SIRT7 gene, in which, HDAC3 collaborated with C/EBPα to occupy its responding element in the upstream region of SIRT7 gene and repressed its expression in human cells.