The proteome of goat meat exudate: Temporal proteomics as a new way to uncover the underlying mechanisms of meat tenderization.

The effects of ante-mortem stressors such as stunning, struggling, environmental temperature and feed withdrawal on the biochemical changes of broiler breast muscle are assessed in relation to post-mortem biochemical changes and the subsequent tenderness of broiler breast meat. The findings of investigations concerned with broiler meat are presented alongside more fundamental studies addressing such aspects as Ca2+ release and sequestration, endocrine changes during periods of stress and the role of fatty acids as regulators of membrane bound channels. An attempt is made to assimilate the pertinent facts associated with this topic and to give directions for future research. It is concluded, however, that, whilst tenderness in meat is often associated with a loss of ATP, glycogen breakdown and lactic acid accumulation within muscles, current data are insufficient to enable a definitive decision to be made as to which have adverse effects on broiler meat tenderness.

Although DNA methylation is considered to play an important role during myogenic differentiation, chronological alterations in DNA methylation and gene expression patterns in this process have been poorly understood. Using the Infinium HumanMethylation450 BeadChip array, we obtained a chronological profile of the genome-wide DNA methylation status in a human myoblast differentiation model, where myoblasts were cultured in low-serum medium to stimulate myogenic differentiation. As the differentiation of the myoblasts proceeded, their global DNA methylation level increased and their methylation patterns became more distinct from those of mesenchymal stem cells. Gene ontology analysis revealed that genes whose promoter region was hypermethylated upon myoblast differentiation were highly significantly enriched with muscle-related terms such as 'muscle contraction' and 'muscle system process'. Sequence motif analysis identified 8-bp motifs somewhat similar to the binding motifs of ID4 and ZNF238 to be most significantly enriched in hypermethylated promoter regions. ID4 and ZNF238 have been shown to be critical transcriptional regulators of muscle-related genes during myogenic differentiation. An integrated analysis of DNA methylation and gene expression profiles revealed that de novo DNA methylation of non-CpG island (CGI) promoters was more often associated with transcriptional down-regulation than that of CGI promoters. These results strongly suggest the existence of an epigenetic mechanism in which DNA methylation modulates the functions of key transcriptional factors to coordinately regulate muscle-related genes during myogenic differentiation.

Tenderness is the most important meat quality trait, which is determined by intracellular environment and extracellular matrix. Particularly, specific protein degradation and protein modification can disrupt the architecture and integrity of muscle cells so that improves the meat tenderness. Endogenous proteolytic systems are responsible for modifying proteinases as well as the meat tenderization. Abundant evidence has testified that calpains (CAPNs) including calpain I (CAPN1) and calpastatin (CAST) have the closest relationship with tenderness in livestock. They are involved in a wide range of physiological processes including muscle growth and differentiation, pathological conditions and post-mortem meat aging. Whereas, Calpain3 (CAPN3) has been established as an important activating enzyme specifically expressed in livestock’s skeletal muscle, but its role in domestic animals meat tenderization remains controversial. In this review, we summarize the role of CAPN1, calpain II (CAPN2) and CAST in post-mortem meat tenderization, and analyse the relationship between CAPN3 and tenderness in domestic animals. Besides, the possible mechanism affecting post-mortem meat aging and improving meat tenderization, and current possible causes responsible for divergence (whether CAPN3 contributes to animal meat tenderization or not) are inferred. Only the possible mechanism of CAPN3 in meat tenderization has been confirmed, while its exact role still needs to be studied further.

introduction: Bisphenol A (BPA) is an environmental toxin commonly found in plastics and is able to mimic the actions of endogenous steroid hormones. BPA binds and activates intracellular estrogen receptors (eRα and eRβ) and estrogen related receptor γ (eRRγ), all of which are present in cardiomyocytes. however, it is unclear how BPA impacts the heart. We hypothesized that BPA modulates the expression of proteins regulating cardiac structure, energy and calcium homeostasis during cardiomyocyte differentiation in vitro. Methods: We differentiated h9C2 cells into cardiomyocytes in hormone-replete (Rm) or hormone-depleted (hD) media. We co-treated the cells with graded amounts of Bpa and pure anti-estrogen ICI 182,780, which blocks eRα and eRβ activity. Immunoblotting measured the expression of the structural protein β-myosin heavy chain (βmhC), calcium homeostasis protein sarcoendoplasmic reticulum calcium aTpase (seRCa2a), and the cardiac energy-producing protein creatine kinase (CK). results: expression of these proteins was hormone-dependent during cardiomyocyte differentiation, with expression highest in Rm media after 72 or 96 hours of differentiation. adding 10-8 m BPA to hD media increased cardiac structural (βmhC), energy (CK), and calcium homeostasis (seRCa2a) protein expression. Conversely, 10-7 m BPA added to Rm media decreased protein expression. Co-treatment with ICI 182,780 reduced Bpa-mediated induction of seRCa2a and CK expression in hD media. discussion: BPA modulates cardiac structure, calcium and energy homeostasis protein expression during cardiomyocyte differention in vitro. moreover, the data suggest that BPA mediates these changes in protein expression through activation of cardiomyocyte eRα, eRβ, or eRRγ.

Coronary artery bypass graft (CABG) is the surgical method most commonly used to treat coronary artery disease (CAD). The vessels that are used in CABG are usually the internal thoracic artery (ITA) and the saphenous vein (SV). Transplant patency is one of the most important factors affecting transplant success. In this study, we used an expressive microarray method, approved by RT-qPCR, for transcriptome analysis of arterial and venous grafts. In the search for potential molecular factors, we analyzed gene ontologies of different expression based on the muscular system. Among interesting groups, we distinguished muscle cell proliferation, muscle contraction, muscle system process, regulation of smooth muscle cell proliferation and smooth muscle cell proliferation. The highest increase in gene expression was observed in: ACTN2, RBPMS2, NR4A3, KCNA5, while the smallest decrease in expression was shown by the P2RX1, KCNH2, DES and MYOT genes. Particularly noteworthy are the ACTN2 and NR4A3 genes, which can have a significant impact on vascular patency. ACTN2 is a gene that can affect the formation of atherosclerotic plaques, while NR4A3 occurs in 4 of the 5 ontological groups discussed and can affect the inflammatory process in the blood vessel. To summarize, the presented study provided valuable insight into the molecular aspects characterizing the vessels used in CABG, and in particular identified genes that may be the target for further studies on duct patency. Running title: CABG grafts’ molecular analysis of ‘muscle system process’

Long non-coding RNAs (lncRNAs) play important roles in the growth and development of skeletal muscle. However, there is limited information on goats. In this study, expression profiles of lncRNAs in Longissimus dorsi muscle from Liaoning cashmere (LC) goats and Ziwuling black (ZB) goats with divergent meat yield and meat quality were compared using RNA-sequencing. Based on our previous microRNA (miRNA) and mRNA profiles obtained from the same tissues, the target genes and binding miRNAs of differentially expressed lncRNAs were obtained. Subsequently, lncRNA-mRNA interaction networks and a ceRNA network of lncRNA-miRNA-mRNA were constructed. A total of 136 differentially expressed lncRNAs were identified between the two breeds. Fifteen cis target genes and 143 trans target genes were found for differentially expressed lncRNAs, and they were enriched in muscle contraction, muscle system process, muscle cell differentiation, and p53 signaling pathway. A total of 69 lncRNA-trans target gene pairs were constructed, with close relationship with muscle development, intramuscular fat deposition, and meat tenderness. A total of 16 lncRNA-miRNA-mRNA ceRNA pairs were identified, of which some reportedly associated with skeletal muscle development and fat deposition were found. The study will provide an improved understanding of the roles of lncRNAs in caprine meat yield and meat quality.

Oula Tibetan sheep meat is rich in nutrients, but its tenderness is relatively poor. Therefore, exploring meat tenderization methods is crucial. Previous studies have indicated that reactive species generated by plasma promote mitochondrial dysfunction and induce apoptosis in tumor cells. However, the impacts of plasma treatment on mitochondrial pathway apoptosis and the tenderization of Oula Tibetan sheep meat have not been reported. This study aimed to explore the effects of cold atmospheric plasma (CAP) treatment on mitochondrial pathway apoptosis and meat tenderness of Tibetan sheep meat during postmortem aging. The results showed that after CAP treatment, reactive oxygen species (ROS) and nitric oxide (NO) content increased, pH value and ATP content decreased, resulting in an increase in mitochondrial permeability transition pore (MPTP) opening, a decrease in succinate dehydrogenase (SDH) activity,Cytochrome c (Cyt-c) reduction level and mitochondrial membrane potential (MMP), and an increase in Caspase-3/9 activity, promoting the occurrence of mitochondrial pathway apoptosis. Meanwhile, myofibril fragmentation index(MFI) increased, shear force value decreased and the mitochondrial structure was obviously damaged. The results of the correlation analysis showed that the degree of mitochondrial damage was significantly positively correlated with the tenderization of the meat during postmortem aging. Therefore, CAP treatment promoted mitochondrial pathway apoptosis and muscle tenderization during postmortem aging of Tibetan sheep meat by increasing the content of ROS and NO and altering the intracellular environment of muscle cells, thereby intensifying mitochondrial damage. The study can provide a theoretical basis for CAP treatment to improve the tenderness of Tibetan sheep meat. PRACTICAL APPLICATIONS: The results of this study indicate that CAP treatment can improve the tenderness of Tibetan sheep meat by promoting apoptosis in the mitochondrial pathway. Therefore, CAP treatment may be used as a nonthermal processing technology to effectively improve the tenderness of Tibetan sheep meat.

Postmortem interval (PMI) estimation is a challenge of utmost importance in forensic daily practice. Traditional methods face limitations in accuracy and reliability, particularly for advanced decomposition stages. Recent advances in "omics" sciences, providing a holistic view of postmortem biochemical changes, offer promising avenues for overcoming these challenges. This systematic review aims at investigating the role of mass-spectrometry-based "omics" approaches in PMI estimation to elucidate molecular mechanisms underlying predictable time-dependent biochemical alterations occurring after death. A systematic search was performed, adhering to PRISMA guidelines, through "free-text" protocols in the databases PubMed, SCOPUS and Web of Science. The inclusion criteria were as follows: experimental studies analyzing, as investigated samples, animal or human corpses in toto or in parts and estimating PMI through MS-based untargeted omics approaches, with full texts in the English language. Quality assessment was performed using STROBE and ARRIVE critical appraisal checklists. A total of 1152 papers were screened and 26 included. Seventeen papers adopted a proteomic approach (65.4%), nine focused on metabolomics (34.6%) and two on lipidomics (7.7%). Most papers (57.7%) focused on short PMIs (<7 days), the remaining papers explored medium (7-120 days) (30.77%) and long PMIs (>120 days) (15.4%). Muscle tissue was the most frequently analyzed substrate (34.6% of papers), followed by liver (19.2%), bones (15.4%), cardiac blood and leaking fluids (11.5%), lung, kidney and serum (7.7%), and spleen, vitreous humor and heart (3.8%). Predictable time-dependent degradation patterns of macromolecules in different biological substrates have been discussed, with special attention to molecular insights into postmortem biochemical changes.

Effects of Electric Treatments and Wing Restraints on the Rate of Post-Mortem Biochemical Changes and Objective Texture of Broiler Pectoralis Major Muscles Deboned After Chilling

Objectives: Estimation of post mortem interval (PMI) remains one of the most difficult challenges to a medicolegal expert. Postmortem biochemical changes may provide chemical markers to help more accurate determination of the postmortem interval. Obtaining postmortem blood samples is a simple and non invasive procedure. The purpose of the study was first, to compare time dependent changes in concentrations of NADH, ammonia and uric acid versus morphological changes of white blood cells of in-vitro stored and postmortem blood samples for each time points 0, 12,24,48and72h. Second to find out an objective and quantitative standard for the estimation of postmortem interval. Materials and Methods: This study was carried out on blood samples collected from 30 healthy volunteers (group I) and 30 medicolegal autopsy cases (group II). Changes in concentration of NADH, ammonia and uric acid were recorded at (0, 12, 24, 48 and 72h) of postmortem and storage periods. Also, blood films have been examined using a light microscope after staining with Giemsa stain to observe and compare morphological changes of white blood cells at the previous time intervals. Results: Concentrations of NADH, ammonia were significantly increased with time in (group II) while, uric acid showed no significance increase between both groups for the whole 72 hours. Also, degenerative morphological changes in white blood cells were in the form of pyknosis, cytoplasmic and nuclear vacuolation, nuclear fragmentation and disintegration. These changes were the same in both groups all over the time points of the study. Conclusion: From the previous results, it can be concluded that there were time dependent changes in NADH and ammonia levels, degenerative morphological changes of white blood cells. Also, there was a strong positive correlation between concentrations of plasma NADH and neutrophilic changes all over the time points of the study in the medicolegal autopsy cases.

Effects of Electrical Stimulation on the Post-Mortem Biochemical Changes and Texture of Broiler Pectoralis Muscle

Testosterone replacement therapy (TRT) added to lifestyle therapy can mitigate weight-loss-induced reduction of muscle mass and bone mineral density (BMD) in older men with obesity and hypogonadism. To investigate the molecular mechanisms underlying the attenuation of muscle and BMD loss in response to TRT during intensive lifestyle intervention in this high-risk older population. Among 83 older (≥ 65 years) men with obesity (BMI ≥ 30 kg/m2) and hypogonadism (early AM testosterone persistently < 300 ng/dL) associated with frailty (Modified Physical Performance Test score ≤ 31) randomized into 26-week lifestyle therapy plus testosterone (LT+TRT) or placebo (LT+Pbo) in the LITROS trial, 38 underwent serial muscle biopsies for the muscle transcriptomics substudy. Despite similar ~10% weight loss, lean body mass and thigh muscle volume decreased less in LT+TRT than LT+Pbo (-2% vs. -4%, respectively; p = 0.04). Hip BMD was preserved in LT+TRT compared with LT+Pbo (0.4% vs. -1.3%; p = 0.03). Muscle strength increased similarly in LT+TRT and LT+Pbo (23% vs. 24%; p = 0.95). Total testosterone increased more in LT+TRT than LT+Pbo (133% vs. 32%; p = 0.005). Based on Next Generation Sequencing, of the 39 160 and 39 115 genes detected in LT+TRT and LT+Pbo, respectively, 195 were differentially expressed in LT+TRT and 158 in LT+Pbo. Gene Ontology enrichment analyses revealed that in LT+TRT, just four muscle-related pathways (muscle organ development, muscle organ morphogenesis, regulation of skeletal muscle contraction, muscle atrophy) were downregulated and one pathway (muscle system process) was upregulated. In contrast, in LT+Pbo, nine muscle-related pathways (muscle system process, muscle tissue development, muscle organ development, skeletal muscle tissue development, skeletal muscle organ development, skeletal muscle cell differentiation, muscle organ morphogenesis, response to stimuli involved in regulation of muscle adaptation, muscle atrophy) and one pathway related to bone (bone mineralization involved in bone maturation) were downregulated. Muscle system process was upregulated in LT+TRT but downregulated in LT+Pbo. RT-PCR analyses showed that LT+TRT resulted in a higher expression of MYOD1 (p = 0.02) and WNT4 (p = 0.02), key genes involved in muscle and bone metabolism, respectively, compared with LT+Pbo. We also observed significantly higher mRNA expression of MYBPH (p = 0.006), SCN3B (p = 0.02) and DSC2 (p = 0.01), genes involved in the muscle system process, in response to LT+TRT compared with LT+Pbo. The addition of TRT to lifestyle therapy mitigates the weight-loss-induced reduction of muscle mass and BMD via countering the weight-loss-induced downregulation of genes involved in muscle and bone anabolism.

Disclosure: V. Viola: None. T. Samanta: None. M. Duremdes Nava: None. A. Celli: None. R.C. Villareal: None. N.H. Nguyen: None. G. Colleluori: None. Y. Barnouin: None. N. Napoli: None. C. Qualls: None. B.A. Kaipparettu: None. D.T. Villareal: None. Background: We reported that testosterone replacement added to lifestyle therapy can mitigate weight loss-induced reduction of muscle mass and bone mineral density (BMD) in older men with obesity and hypogonadism (Barnouin et al., J Clin Endocrinol Metab, 2021). Objective: To investigate the molecular mechanisms underlying the mitigation of muscle and BMD loss in response to testosterone replacement therapy during intensive lifestyle intervention in this at-risk population. Materials and Methods: Among the 83 older (≥ 65 y) men with obesity (BMI ≥ 30 kg/m2) and hypogonadism (early AM testosterone persistently &amp;lt;300 ng/dl) associated with frailty (PPT score ≤ 31) who were randomized into 26-week lifestyle therapy plus testosterone (LT+Test) or placebo (LT+Pbo), 38 underwent serial muscle biopsies for the muscle transcriptomics substudy. Results: Despite a similar 9% weight loss, lean body mass and thigh muscle volume decreased less in LT+Test than LT+Pbo (both -2% vs -4%, respectively; p=0.04). Hip BMD was preserved in LT+Test compared with LT+Pbo (0.4% vs -1.1%; p=0.03). Muscle strength increased similarly in LT+Test and LT+Pbo (23% vs 24%; p=0.95). Total testosterone increased more in LT+Test than LT+Pbo (133% vs 32%; p=0.01). Based on Next Generation Sequencing, of the 39,160 and 39,115 genes detected in LT+Test and LT+Pbo, respectively, 151 genes were differentially expressed (DEGs) in LT+Test and 114 in LT+Pbo group. Gene Ontology enrichment analyses revealed that in the LT+Test group, just four muscle-related terms (muscle organ development, muscle organ morphogenesis, regulation of skeletal muscle contraction, muscle atrophy) were downregulated, and one term (muscle system process) was upregulated while in the LT+Pbo, nine terms related to muscle (muscle system process, muscle tissue development, muscle organ development, skeletal muscle tissue development, skeletal muscle organ development, skeletal muscle cell differentiation, muscle organ morphogenesis, response to stimuli involved in regulation of muscle adaptation, muscle atrophy), and one term related to bone (bone mineralization involved in bone maturation) were downregulated. Notably, muscle system process was upregulated in the LT+Test but downregulated in the LT+Pbo. The RT-PCR analyses showed that LT+Test resulted in a higher expression of MYOD1 (p=0.02) and WNT4 (p= 0.08), key genes involved in muscle and bone metabolism, respectively, compared to LT+Pbo. Furthermore, we observed significantly higher mRNA expression of MYBPH (p=0.01), SCN3B (p=0.02), and DSC2 (p=0.01), genes involved in the muscle system process, in response to LT+Test compared to LT+Pbo. Conclusion: The addition of testosterone replacement to lifestyle therapy mitigates the weight loss-induced reduction of muscle mass and BMD via countering the weight loss-induced downregulation of genes involved in muscle and bone anabolism. Presentation: 6/2/2024

Acetylome profiling reveals extensive involvement of lysine acetylation in the conversion of muscle to meat

Meat tenderness is key to consumer acceptance but is challenged by goat meat’s leanness and high connective tissue content. A promising solution is the in-pack combination of ultrasonication (US) and sous-vide (SV) technologies to enhance tenderness while ensuring product safety. This study investigates the individual and combined effects of US and SV on biochemical and molecular changes in goat meat during the first 48 h post-mortem, focusing on glycolysis, proteolysis, apoptosis, and water retention, compared to an untreated control (C). At 48 h post-mortem, US + SV resulted in the fastest pH decrease (p < 0.05), correlating with glycogen and ATP depletion and lactate accumulation, indicating accelerated glycolysis and hastened rigor mortis. Both US and SV individually enhanced sarcoplasmic and myofibrillar protein degradation, as shown by increased solubility and myofibrillar fragment index (MFI), and their combination had a synergistic effect on proteolysis. Only US + SV promoted collagen degradation (p < 0.05). US alone accelerated ATP degradation, whereas SV had no significant effect (p > 0.05), suggesting minimal impact on energy metabolism. SV enhanced US-driven proteolysis, likely by stabilizing proteolytic enzyme activity to function effectively in catalyzing the breakdown of proteins. Gene expression analysis confirmed that US + SV and US induced early apoptosis and proteolysis, particularly within the first 12 h, which corresponded to lower Warner-Bratzler Shear Force (WBSF) values, indicating improved meat tenderness. Despite higher weight loss, US + SV improved cooking loss compared to C (p < 0.05). These findings suggest that US + SV accelerates proteolysis and enhances meat tenderness, providing valuable insights for the meat industry in optimizing post-mortem processing techniques.Supplementary InformationThe online version contains supplementary material available at 10.1007/s44463-025-00028-7.