FHL2 Regulates Proliferation Differentiation and Autophagy of Bovine Skeletal Muscle Satellite Cells Through Wnt/β-catenin Signaling Pathway

The mechanism of physiological regulation of bovine skeletal muscle development is a complex process, and FHL2 has been studied in association with β-catenin activity and has previously been reported to play a role in skeletal muscle.However the mechanism of FHL2 action in regulating skeletal muscle development in bovine skeletal myosatellite is unclear. Here, we report that FHL2 can both promote the proliferation and differentiation of bovine myosatellite cells through the wnt signaling pathway and bovine skeletal muscle satellite cells through cellular autophagy. The results of western blotting, rt-qPCT, cell transfection assay showed that FHL2 gene expression was enhanced during the proliferation of skeletal muscle satellite cells, and FHL2 knockdown inhibited the proliferation and differentiation of bovine satellite cells and promoted the atrophy of myotubes. Furthermore, immunoprecipitation assays yielded that FHL2 knockdown decreased β-catenin activity in BMSCs and activated β-catenin-mediated wnt signaling pathway in combination with DVL-2, and that FHL2 knockdown induced autophagy in bovine satellite cells. Therefore, the FHL2 gene is a key gene in the regulation of bovine satellite cells.

Integrated Analysis of mRNA and MicroRNA Co-expressed Network for the Differentiation of Bovine Skeletal Muscle Cells After Polyphenol Resveratrol Treatment

Resveratrol (RSV) has been confirmed to benefit human health. Resveratrol supplemented in the feeds of animals improved pork, chicken, and duck meat qualities. In this study, we identified differentially expressed (DE) messenger RNAs (mRNAs) (n = 3,856) and microRNAs (miRNAs) (n = 93) for the weighted gene co-expression network analysis (WGCNA) to investigate the co-expressed DE mRNAs and DE miRNAs in the primary bovine myoblasts after RSV treatment. The mRNA results indicated that RSV treatments had high correlations with turquoise module (0.91, P-value = 0.01) and blue module (0.93, P-value < 0.01), while only the turquoise module (0.96, P-value < 0.01) was highly correlated with the treatment status using miRNA data. After biological enrichment analysis, the 2,579 DE genes in the turquoise module were significantly enriched in the Gene Ontology (GO) terms and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. The top two GO terms were actin filament-based process (GO:0030029) and actin cytoskeleton organization (GO:0030036). The top two KEGG pathways were regulation of actin cytoskeleton (bta04810) and tight junction (bta04530). Then, we constructed the DE mRNA co-expression and DE miRNA co-expression networks in the turquoise module and the mRNA–miRNA targeting networks based on their co-expressions in the key module. In summary, the RSV-induced miRNAs participated in the co-expression networks that could affect mRNA expressions to regulate the primary myoblast differentiation. Our study provided a better understanding of the roles of RSV in inducing miRNA and of the characteristics of DE miRNAs in the key co-expressed module in regulation of mRNAs and revealed new candidate regulatory miRNAs and genes for the beef quality traits.

The effect of postmortem pH decline rate on mitochondrial apoptosis and tenderness of bovine skeletal muscle during aging

This study aimed to investigate the effect of postmortem pH decline rate on mitochondrial dysfunction-induced apoptosis and bovine muscle tenderness during aging. Protein denaturation, reactive oxygen species (ROS) levels, mitochondrial apoptosis factors, and shear force were assessed in bovine muscles with different pH decline rates. The results showed that compared to the slow group, fast pH decline in bovine muscle significantly increased sarcoplasmic protein denaturation at 6–12 h and mitochondrial ROS levels at 6–24 h (P<0.05), and in turn significantly accentuated mitochondrial dysfunction and cytochrome c oxidation levels (P<0.05), resulting in caspase-3 activation, apoptosis, and reduced muscle shear force (P<0.05). These results demonstrated that the fast postmortem pH decline enhanced mitochondrial apoptosis and bovine muscle tenderization by inducing ROS accumulation during aging.

Proteomic Studies on the Mechanism of Myostatin Regulating Cattle Skeletal Muscle Development

Myostatin (MSTN) is an important negative regulator of muscle growth and development. In this study, we performed comparatively the proteomics analyses of gluteus tissues from MSTN+/− Mongolian cattle (MG.MSTN+/−) and wild type Mongolian cattle (MG.WT) using a shotgun-based tandem mass tag (TMT) 6-plex labeling method to investigate the regulation mechanism of MSTN on the growth and development of bovine skeletal muscle. A total of 1,950 proteins were identified in MG.MSTN+/− and MG.WT. Compared with MG.WT cattle, a total of 320 differentially expressed proteins were identified in MG.MSTN cattle, including 245 up-regulated differentially expressed proteins and 75 down-regulated differentially expressed proteins. Bioinformatics analysis showed that knockdown of the MSTN gene increased the expression of extracellular matrix and ribosome-related proteins, induced activation of focal adhesion, PI3K-AKT, and Ribosomal pathways. The results of proteomic analysis were verified by muscle tissue Western blot test and in vitro MSTN gene knockdown test, and it was found that knockdown MSTN gene expression could promote the proliferation and myogenic differentiation of bovine skeletal muscle satellite cells (BSMSCs). At the same time, Co-Immunoprecipitation (CO-IP) assay showed that MSTN gene interacted with extracellular matrix related protein type I collagen α 1 (COL1A1), and knocking down the expression of COL1A1 could inhibit the activity of adhesion, PI3K-AKT and ribosome pathway, thus inhibit BSMSCs proliferation. These results suggest that the MSTN gene regulates focal adhesion, PI3K-AKT, and Ribosomal pathway through the COL1A1 gene. In general, this study provides new insights into the regulatory mechanism of MSTN involved in muscle growth and development.

PSV-13 Understanding the role of zinc and manganese in proliferation and protein synthesis of primary bovine satellite cells

Trace minerals are vital for the health and growth of livestock, supporting multiple biochemical processes in the body. There are several different signaling pathways that may be affected by trace minerals, ultimately altering growth of skeletal muscle. However, it is currently unknown how trace minerals specifically impact growth of skeletal muscle. As such, the objective of this study was to determine how zinc (Zn) and manganese (Mn) affect proliferation and protein synthesis of primary bovine satellite cell (BSC) cultures. Cultures were grown to 80% confluency and treated in 1% fetal bovine serum (control), 0.05, 0.10 or 0.25 µM of Mn, or 10, 20 or 40 µM of Zn to assess proliferation. Additionally, the above treatments were applied to fused BSC cultures in serum free media (control) to measure protein synthesis. The trace mineral concentrations chosen were based off known ranges of circulating concentrations of Zn or Mn. A series of contrasts were constructed to determine whether growth of BSC cultures was different between the treated and control cultures. Treatment with 10 µM Zn increased (P = 0.03) proliferation when compared to control cultures. However, treatment with Mn at the tested concentration did not (P &gt; 0.12) result in proliferation rates that were different than the control cultures. Treatment with 10 µM Zn, 20 µM Zn, or 0.5 µM Mn increased (P &lt; 0.05) protein synthesis compared to control cultures. These results indicate Zn is capable of increasing proliferation and both Zn and Mn increase protein synthesis of BSC cultures. Additional research is needed to couple trace mineral nutrition with knowledge of BSC biology to elucidate the molecular mechanisms by which trace minerals may function to support bovine skeletal muscle growth.

Varying of up-conversion nanoparticles luminescence from the muscle tissue depth during the compression

The current work is focused on the study of optical clearing of skeletal muscles under local compression. The experiments were performed on in vitro bovine skeletal muscle. The time dependence of optical clearing was studied by monitoring the luminescence intensity of NaYF4:Er,Yb upconverting particles located under tissue layers. This study shows the possibility to use upconverting nanoparticles (UCNPs) both for studying the dynamics of the optical clearing of biological tissue under compression and to detect moments of cell wall damage under excessive pressure. The advantage of using UCNPs is the presence of several bands in their luminescence spectra, located both at close wavelengths and far apart.