Epigenetic and molecular mechanisms underlying gene expression in porcine skeletal muscle and satellite cells

Epigenetic studies have been conducted in association with skeletal muscle only during the last years. We performed in vivo study in skeletal muscle and in vitro study in satellite cells with the aims to understand the epigenetic mechanisms regulating muscle gene expression. Duroc and Pietrain pigs, representing two extremes in skeletal muscle phenotypes, were selected for the in vivo study. Myogenic factor 6 (MYF6) was selected as one of the contributing factors to the postnatal breed-specific muscle properties in two breed pigs. Quantitative real time PCR (qRT-PCR) and Western blotting results revealed that mRNA and protein expression of MYF6 were dramatically higher in Pietrain pigs compared to Duroc pigs and suggested breed-specific expression. Variations in DNA methylation of the MYF6 gene 5´-regulatory region, particularly within important transcription factor binding elements, are shown to occur between breeds. However, in Pietrains pigs, higher expression of MYF6 is not consistent with hypermethylation status, but concurrent with enriched E2F1 expression. In addition to its practical implications, this work extends our understanding the role of epigenetic mechanism in postnatal pigs. Satellite cells, acting as the muscle stem cells to support postnatal muscle growth, were selected for the in vitro study. Sulforaphane (SFN), a novel and natural histone deacetylase (HDAC) inhibitor, was selected as the treatment epigenetic reagent. Apart from SFN, we also employed the typical epigenetic reagents 5-aza-2′-deoxycytidine (5-aza-dC) and trichostatin (TSA). Distinguished from TSA, SFN and 5-aza-dC remarkably suppress myostatin (MSTN) expression and inhibit HDAC activity as well as DNA methyltransferase (DNMT) expression. SFN, 5-aza-dC and TSA exhibited differential mechanisms to repress MSTN expression and negative regulators of MSTN pathway. Deregulated miRNA may be excluded from epigenetic repression of MSTN. However, epigenetic suppression of MSTN by 5-aza-dC and SFN is associated with the decreased myoblast determination protein (MyoD) expression, reduced binding of MyoD on MSTN promoter and hypoacetylation in MyoD binding site. These observations manifest a novel mechanism for manipulation of muscle cell phenotypes.Epigenetische und molekulare Mechanismen die der Genexpression in porcinen Skelettmuskel und Satellitenzellen zugrunde liegen den letzten Jahren wurden epigenetische Studien nur in Zusammenhang mit der Skelettmuskulatur umgesetzt. Wir hingegen führten in vivo Studien an der Skelettmuskulatur und in vitro Studien in Satellitenzellen durch, mit dem Ziel ein besseres Verständnis der epigenetischen Mechanismen zu erlangen, die einen Effekt auf die Regulierung von relevanten Muskelgenen haben könnten. Für die in vitro Studie wurden Duroc und Pietrain Schweine, die sich in ihrem Phänotyp der Skelettmuskulatur stark unterscheiden, ausgesucht. Myogener Faktor 6 (Myf6) gilt als ein entscheidender Faktor für postnatale rassenspezifische Muskeleigenschaften in zwei Rassen. Quantitative real time PCR (qRT-PCR) und Western Blot Ergebnisse zeigten, dass die Myf6 mRNA- und Protein-Expression dramatisch höher bei Pietrain im Vergleich zu Duroc Schweinen waren. Dieses kann auf eine rassenspezifische Expression hindeuten. Variationen in der DNA-Methylierung des Myf6 Gens in der 5´regulierenden Region, speziell innerhalb wichtiger Transkriptionsfaktorbindeelementes, konnten zwischen den Rassen ermittelt werden. Doch zeigte sich bei der Rasse Pietrain, dass eine höhere Expression von Myf6 nicht übereinstimmend mit dem Hypermethylierungsstatus ist, sondern mit einer hohen E2F1 Expression konkurriert. Zusätzlich zu den praktischen Implikationen erweitert diese Studie unser Verständnis über die Rolle des epigenetischen Mechanismus in postnatalen Schweinen. Für die in vitro Studie wurden Satellitenzellen als Muskelstammzellen, die das postnatale Muskelwachstum unterstützen, verwendet. Sulforaphane (SFN), ein neuartiger und natürlicher Histon Deacetylase (HDAC) Inhibitor, wurde als ein epigenetisches Behandlungsreagenz ausgewählt. Neben SFN setzten wir weitere typische epigenetische Reagenzien wie 5- Aza-2′-deoxycytidine (5-aza-dC) und Trichostatin (TSA) ein. Im Gegensatz zu TSA zeigen SFN und 5-aza-dC die Eigenschaft, nicht nur die HDAC Aktivität zu unterdrücken sondern auch die DNA-Methyltransferase Expression (DNMT) und die Expression von Myostatin (MSTN). SFN, 5-aza-dC und TSA weisen unterschiedliche Mechanismen auf, um die Expression von MSTN und negativen Regulatoren des MSTN Signalwegs zu unterdrücken. Deregulierte miRNA wird vielleicht von der epigenetischen Unterdrückung von MSTN ausgenommen. Jedoch kann die epigenetische Unterdrückung von MSTN durch 5-aza-dC und SFN mit einer verringerten Myoblast Determination Protein (MyoD) Expression assoziiert werden durch reduzierte Bindung von MyoD an den MSTN Promotor und Hypoacetylierung der MyoD Bindungsstelle. Diese Beobachtungen manifestieren einen neuartigen Mechanismus zur Manipulation des Muskelzellphänotypen

Out-of-Time-Order Correlation at a Quantum Phase Transition

In this paper we numerically calculate the out-of-time-order correlation functions in the one-dimensional Bose-Hubbard model. Our study is motivated by the conjecture that a system with Lyapunov exponent saturating the upper bound $2\pi/\beta$ will have a holographic dual to a black hole at finite temperature. We further conjecture that for a many-body quantum system with a quantum phase transition, the Lyapunov exponent will have a peak in the quantum critical region where there exists an emergent conformal symmetry and is absent of well-defined quasi-particles. With the help of a relation between the R\'enyi entropy and the out-of-time-order correlation function, we argue that the out-of-time-order correlation function of the Bose-Hubbard model will also exhibit an exponential behavior at the scrambling time. By fitting the numerical results with an exponential function, we extract the Lyapunov exponents in the one-dimensional Bose-Hubbard model across the quantum critical regime at finite temperature. Our results on the Bose-Hubbard model support the conjecture. We also compute the butterfly velocity and propose how the echo type measurement of this correlator in the cold atom realizations of the Bose-Hubbard model without inverting the Hamiltonian.Comment: 7 pages, 6 figures, published versio

Out-of-Time-Order Correlation for Many-Body Localization

In this paper we first compute the out-of-time-order correlators (OTOC) for both a phenomenological model and a random-field XXZ model in the many-body localized phase. We show that the OTOC decreases in power law in a many-body localized system at the scrambling time. We also find that the OTOC can also be used to distinguish a many-body localized phase from an Anderson localized phase, while a normal correlator cannot. Furthermore, we prove an exact theorem that relates the growth of the second R\'enyi entropy in the quench dynamics to the decay of the OTOC in equilibrium. This theorem works for a generic quantum system. We discuss various implications of this theorem.Comment: 6 pages, 3 figures, published versio

Dufulin Activates HrBP1 to Produce Antiviral Responses in Tobacco

BACKGROUND: Dufulin is a new antiviral agent that is highly effective against plant viruses and acts by activating systemic acquired resistance (SAR) in plants. In recent years, it has been used widely to prevent and control tobacco and rice viral diseases in China. However, its targets and mechanism of action are still poorly understood. METHODOLOGY/PRINCIPAL FINDINGS: Here, differential in-gel electrophoresis (DIGE) and classical two-dimensional electrophoresis (2-DE) techniques were combined with mass spectrometry (MS) to identify the target of Dufulin. More than 40 proteins were found to be differentially expressed (≥1.5 fold or ≤1.5 fold) upon Dufulin treatment in Nicotiana tabacum K(326). Based on annotations in the Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) databases, these proteins were found to be related to disease resistance. Directed acyclic graph (DAG) analysis of the various pathways demonstrated harpin binding protein-1 (HrBP1) as the target of action of Dufulin. Additionally, western blotting, semi-quantitative reverse transcription polymerase chain reaction (RT-PCR), and real time PCR analyses were also conducted to identify the specific mechanism of action of Dufulin. Our results show that activation of HrBP1 triggers the salicylic acid (SA) signaling pathway and thereby produces antiviral responses in the plant host. A protective assay based on lesion counting further confirmed the antiviral activity of Dufulin. CONCLUSION: This study identified HrBP1 as a target protein of Dufulin and that Dufulin can activate the SA signaling pathway to induce host plants to generate antiviral responses

The mRNA Expression Pattern of Skeletal Muscle Regulatory Factors in Divergent Phenotype Swine Breeds

Muscle regulatory factors (MRFs) play a major role in muscle growth and development. Thus, they are considered as candidate genes for meat production traits in pigs. These basic helix-loop-helix (bHLH) and paired box transcription factors together with Bone morphogenetic proteins, regulate myogenesis: they initiate the formation of muscle fibers and regulate the transcription of muscle specific genes. The objective of this study was to investigate the mRNA abundance of transcription factor (TF) genes (MYOD, MYF5, MYOG, PAX3, PAX7, BMP2 and BMP4) in the adult skeletal muscle (longissimus dorsi) of divergent Duroc (high meat fat ratio) and Pietrain (low meat fat ratio) pig breeds. For this purpose, purebred Duroc and Pietrain animals (for each breed n = 5) were used for mRNA expression study. Highest gene expression was observed for MYOG, followed by BMP2. The lowest gene expression was observed for PAX3. Moreover, we statistically investigated differences in the expression profiles of these genes between the Duroc and Pietrain breeds. Among seven genes MYF5 and PAX3 showed different expression (P<0.01) between Duroc and Pietrain breeds. Duroc showed higher MYF5 and PAX3 mRNA abundance compared to the Pietrain breed. Although PAX3 gene was the lowest expressed, results suggest that Duroc breed may have more skeletal muscle regeneration potential compared to Pietrain breed

Battery swapping demand simulation for electric micromobility vehicles considering multi-source information interaction and behavior decision

The battery swapping mode has the advantages of convenience and battery controllability, which can alleviate charging problems with electric micromobility vehicles (EMVs). The layout of battery swapping facilities and scheduling management can be carried out by accurately analyzing the high-resolution spatial-temporal distribution of battery swapping demand for EMV. This study establishes a prediction model framework for battery swapping demand of EMV using Monte Carlo simulation based on travel chains considering multi-source information interaction and behavior decision. Using real residential travel survey data of Nanning City, China and an empirical analysis with the city as a case study, the results show that the prediction framework proposed in this study is reliable. The temporal distribution of EMV battery swapping demand is closely related to the spatial distribution of travel. In addition, the demand characteristics of both centralized and decentralized battery swapping stations are evaluated separately. The peak intensity of the centralized mode is 18% greater than that of the decentralized mode when the battery swapping penetration is 35%. When the battery swapping penetration rate is low, decentralized mode can meet the peak swapping demand, and as the penetration rate increases, the effect of centralized mode is reflected. Finally, the total swapping path time considering multi-source information interaction and behavior decision is reduced by 7.8%. These findings allow for the study of battery swapping station planning and transportation planning.</p

Study on Flake Formation Behavior and Its Influence Factors in Cr5 Steel

A flake is a crack that is induced by trapped hydrogen within steel. To study its formation mechanism, previous studies mostly focused on the formation process and magnitude of hydrogen pressure in hydrogen traps such as cavities and cracks. However, according to recent studies, the hydrogen leads to the decline of the mechanical properties of steel, which is known as hydrogen embrittlement, is another reason for flake formation. In addition, the phenomenon of stress induced hydrogen uphill diffusion should not be neglected. All of the three behaviors are at work simultaneously. In order to further explore the formation mechanism of flakes in steel, the process of flake initiation and growth were studied with the following three coupling factors: trap hydrogen pressure, hydrogen embrittlement, and stress induced hydrogen re-distribution. The analysis model was established using the finite element method, and a crack whose radius is 0.5 mm was set in its center. The cohesive method and Bilinear Traction Separate Law (BTSL) were used to address the coupling effect. The results show that trap hydrogen pressure is the main driving force for flake formation. After the high hydrogen pressure was generated around the trap, a stress field formed. In addition, the trap is the center of stress concentration. Then, hydrogen is concentrated in a distribution around this trap, and most of the steel mechanical properties are reduced. The trap size is a key factor for defining the critical hydrogen content for flake formation and propagation. However, when the trap size exceeds the specified value, the critical hydrogen content does not change any more. As for the crack whose radius is 0.5 mm, the critical hydrogen content of Cr5VMo steel is 2.2 ppm, which is much closer to the maximum safe hydrogen concentration of 2.0 ppm used in China. The work presented in this article increases our understanding of flake formation and propagation mechanisms in steel

Synthesis, Characterization and Cytotoxicity of Novel Multifunctional Fe3O4@SiO2@GdVO4:Dy3+ Core-Shell Nanocomposite as a Drug Carrier

In this study, multifunctional Fe3O4@SiO2@GdVO4:Dy3+ nanocomposites were successfully synthesized via a two-step method. Their structure, luminescence and magnetic properties were characterized by X-ray diffraction (XRD), scanning electronic microscope (SEM), transmission electron microscopy (TEM), photoluminescence (PL) spectra and vibrating sample magnetometer (VSM). The results indicated that the as-prepared multifunctional composites displayed a well-defined core-shell structure. The composites show spherical morphology with a size distribution of around 360 nm. Additionally, the composites exhibit high saturation magnetization (20.40 emu/g) and excellent luminescence properties. The inner Fe3O4 cores and the outer GdVO4:Dy3+ layers endow the composites with good responsive magnetic properties and strong fluorescent properties, which endow the nanoparticles with great potential applications in drug delivery, magnetic resonance imaging, and marking and separating of cells in vitro