Comparative Proteomics Provides Insights into Metabolic Responses in Rat Liver to Isolated Soy and Meat Proteins

Molecular Changes of Meat Proteins During Processing and Their Impact on Quality and Nutritional Values

Meats are rich in lipids and proteins, exposing them to rapid oxidative changes. Proteins are essential to the human diet, and changes in the structure and functional attributes can greatly influence the quality and nutritional value of meats. In this article, we review the molecular changes of proteins during processing, their impact on the nutritional value of fresh and processed meat, the digestibility and bioavailability of meat proteins, the risks associated with high meat intake, and the preventive strategies employed to mitigate these risks. This information provides new research directions to reduce or prevent oxidative processes that influence the quality and nutritional values of meat.

Integrated Proteotranscriptomics of the Hypothalamus Reveals Altered Regulation Associated with the FecB Mutation in the BMPR1B Gene That Affects Prolificacy in Small Tail Han Sheep

The litter size and ovulation rate are different among ewes of different FecB genotypes in Small Tail Han sheep. These variants in reproductive phenotypes may be regulated by hormones released by the hypothalamic-pituitary-ovarian axis. However, there have been few reports on the hypothalamus regarding regulating an increase in ovulation in sheep with FecB mutation at different estrous stages. Thus, we examined the abundance of hypothalamus tissue protein profiles of six FecB mutant homozygous (BB) and six wild-type (WW) ewes at the luteal and follicular phases. We determined this abundance by tandem mass tag-based quantitative analysis and parallel reaction monitoring methods. Furthermore, an integrated proteotranscriptomic analysis was performed by the Data Integration Analysis for Biomarker discovery using the latent variable approaches for Omics studies (DIABLO) framework to examine biological processes and pathway alterations by the FecB mutant. The abundance of 154 proteins was different between the two estrous stages. Growth hormone and prolactin were particularly enriched in the neuroactive ligand-receptor interactions, the prolactin signaling pathway, and the PI3K-Akt signaling pathway which are related to hypothalamic function and reproduction. We combined proteome and transcriptome data from different estrous stages and genotypes. There is a high correlation (Pearson correlation coefficient = 0.99) between the two datasets in the first two components. We applied the traditional single-omic multivariate approach to obtain differentially abundant proteins and differentially expressed genes. The major fertility related biomarkers were selected using the two approaches mentioned above. Several key pathways (GABAergic synapse, neuroactive ligand-receptor interaction, estrogen and MAPK signaling pathways) were enriched, which are central to gonadotrophin-releasing hormone (GnRH) secretion and reproduction. A higher level of gamma-aminobutyric acid type A receptor subunit alpha1 (GABRA1) and gamma-aminobutyric acid type A receptor subunit beta2 (GABRB2) expression was observed in BB ewes as compared to WW ewes. This finding suggested that a greater production of GnRH during follicular development in BB ewes may explain the higher mature follicle number in mutant ewes. FKBP prolyl isomerase 1A (FKBP1A), which was a major feature factor in the proteome selected by DIABLO, was an important switch for activating the transforming growth factor beta (TGFβ) pathway, and its expression was higher in the WW ewes than in the BB ewes. We suggest that BB sheep maintain TGFβ pathway activity by reducing FKBP1A protein abundance. This innovative data integration in the hypothalamus may provide fresh insight into the mechanisms by which the FecB mutation affects sheep fertility, while providing novel biomarkers related to reproductive endocrinology in sheep breeding.

Intake of a Chicken Protein-Based or Soy Protein-Based Diet Differentially Affects Growth Performance, Absorptive Capacity, and Gut Microbiota in Young Rats

SCOPE

Both plant and animal products provide protein for human demands. However, the effect of protein sources on the physiological responses and the composition and functions of the gut microbiota during the early stage of life have received little attention.

METHODS AND RESULTS

In the present study, chicken protein and soy protein are fed to young weaning rats for 14 days based on the AIN-93G diet formulation. The growth performance is recorded, and the morphology of the small intestine is analyzed to estimate the absorptive capacity. Shotgun metagenomic sequencing is applied to analyze the cecal microbiota. The chicken protein-based diet (CHPD) enhances growth performance and absorptive capacity in young rats compared to the soy protein-based diet (SPD). The CHPD maintains higher levels of Lactobacillus species, associated with glutathione synthesis.

CONCLUSION

The CHPD seems favorable for young growing rats in relation to growth performance and absorptive capacity, correlated with changes in the composition and functional potential of the gut microbiota.

A Comparison Study on the Therapeutic Effect of High Protein Diets Based on Pork Protein versus Soybean Protein on Obese Mice

In this study, an obese C57BL/6J mice model was induced to compare the effect of different high protein diets (soybean protein and pork protein) on obesity. The obese mice were randomly divided into four groups: natural recovery (NR), high-fat diet (HF), high soybean protein diet (HSP), and high pork protein diet (HPP) groups. After 12 weeks of dietary intervention, the obesity-related indexes of mice were measured, such as body weight, fat coefficients, blood lipid indexes and so on. Results showed that HSP and HPP decreased the weight and fat coefficients of mice, the levels of serum total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C) and leptin (p < 0.05). Soybean protein was shown to be more effective in reducing the weight and fat mass of obese mice, although pork protein seemed to have a better effect on regulating serum triglyceride (TG). In addition, the two high protein diets both alleviated hepatic fat deposition effectively. Furthermore, HPP and HSP decreased the expression of hepatic peroxisome proliferator-activated receptor-γ (PPAR-γ) and increased the protein expression of phosphorylated AMP-activated protein kinase (pAMPK), phosphorylated acetyl CoA carboxylase (pACC), and uncoupling protein 2 (UCP2) (p < 0.05). In conclusion, the study shows that high protein diets based on both pork protein and soybean protein alleviated abdominal obesity in mice effectively by regulating lipid metabolism, probably via the UCP2-AMPK-ACC signaling pathway.

Dietary soy, pork and chicken proteins induce distinct nitrogen metabolism in rat liver

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Dietary amino acid composition affected nitrogen metabolism in rat liver.

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Amino acid metabolizing enzymes were downregulated by meat protein diets.

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Ribosome assembly and protein synthesis were regulated by diet by mTOR pathway.

Diets have been shown to alter metabolism and gene expression. However, few data are available about changes in gene expression in liver after intake of different meat protein diets. This work aimed to explore the long-term effects of protein source on liver metabolic enzymes. Rats were fed protein diets for 90 days to study whether intake of chicken and pork protein diets promoted gene expression involved in hepatic metabolism. Liver proteome profiles were measured by iTRAQ labeling and LC–ESI–MS/MS. Chicken protein diet induced higher level of serum amino acids in rats than soy protein. Amino acid metabolizing enzymes were downregulated by pork and chicken protein diets compared with soy protein diet. Intake of meat protein diets downregulated enzymes involved in protein synthesis, disulfide bond formation, signal peptide addition, transport, localization, degradation and glycosylation modification, but upregulated enzymes involved in prolyl cis–trans isomerization for protein synthesis. Protein diets from different sources affected the amino acid supply, and further influenced ribosome assembly and protein synthesis through mTOR signaling pathway.

A Comprehensive Review Evaluating the Impact of Protein Source (Vegetarian vs. Meat Based) in Hepatic Encephalopathy

Hepatic encephalopathy (HE) is a common neurological consequence in patients with cirrhosis and has a healthcare burden of USD 5370 to 50,120 per patient annually. HE significantly hampers the quality of life and is a major cause of morbidity and mortality. Patients with cirrhosis are at a high risk for protein-calorie malnutrition due to altered metabolism. Current evidence has changed the old belief of protein restriction in patients with cirrhosis and now 1.2 to 1.5 g/kg/day protein intake is recommended. Case series and studies with small numbers of participants showed that a vegetarian protein diet decreases the symptoms of HE when compared to a meat-based diet, but the evidence is limited and requires further larger randomized controlled trials. However, vegetable or milk-based protein diets are good substitutes for patients averse to meat intake. Branch chain amino acids (BCAA) (leucine, isoleucine and valine) have also been shown to be effective in alleviating symptoms of HE and are recommended as an alternative therapy in patients with cirrhosis for the treatment of HE. In this review, we provide an overview of current literature evaluating the role of protein intake in the management of HE in cirrhosis.

Effects of Casein, Chicken, and Pork Proteins on the Regulation of Body Fat and Blood Inflammatory Factors and Metabolite Patterns Are Largely Dependent on the Protein Level and Less Attributable to the Protein Source

The impact of meat protein on metabolic regulation is still disputed and may be influenced by protein level. This study aimed to explore the effects of casein, pork, and chicken proteins at different protein levels (40% E vs 20% E) on body weight regulation, body fat accumulation, serum hormone levels, and inflammatory factors/metabolites in rats maintained on high-fat (45% E fat) diets for 84 d. Increased protein levels resulted in a significant reduction in body fat mass and an increase in the serum levels of the anti-inflammatory cytokine IL-10, independent of protein source. Analysis of blood via untargeted metabolomics analysis identified eight, four, and four metabolites significantly altered by protein level, protein source, and a protein level-source interaction, respectively. Together, the effects of casein, chicken, and pork protein on the regulation of body fat accumulation and blood metabolite profile are largely dependent on protein level and less attributable to the protein source.

High intake of chicken and pork proteins aggravates high-fat-diet-induced inflammation and disorder of hippocampal glutamatergic system

High-fat diets have been associated with neurodegenerative diseases, which are also largely related to the type and amount of dietary proteins. However, to our knowledge, it is little known how dietary proteins affect neurodegenerative changes. In this study, we investigated the effects of dietary proteins in a high-fat diet on hippocampus functions related to enteric glial cells (EGCs) in Wistar rats that were fed either 40% or 20% (calorie) casein, chicken protein or pork protein for 12 weeks (n=10 each group). Inflammatory factors, glutamatergic system, EGCs, astrocytes and nutrient transporters were measured. A high-chicken-protein diet significantly increased the levels of systemic inflammatory factors, Tau protein and amyloid precursor protein mRNA level in the rat hippocampus. The type and level of dietary proteins in high-fat diets did not affect the gene expression of glial fibrillary acidic protein and α-synuclein (P>.05), indicating a negligible effect on astrocyte activity. However, the high-protein diets up-regulated glutamate transporters compared with the low-protein diets (P<.05), while they reduced the γ-aminobutyric acid content in high-chicken and -pork-protein diets (P<.05). Thus, compared with a low-protein diet (20%), a high-chicken or -pork-protein diet (40%) under a high-fat background could alter the balance between glutamatergic system and neurotransmitter and have a stronger effect on the interactions between hippocampal glutamatergic system and EGCs.

A Short-Term Feeding of Dietary Casein Increases Abundance of Lactococcus lactis and Upregulates Gene Expression Involving Obesity Prevention in Cecum of Young Rats Compared With Dietary Chicken Protein

Casein and chicken are assessed to contain high quality proteins, which are essential for human health. Studies have shown that ingestion of the two dietary proteins resulted in distinct effects on physiology, liver transcriptome and gut microbiota. However, its underlying mechanism is not fully understood, in particular for a crosstalk between gut microbiota and host under a specific diet intervention. We fed young rats with a casein or a chicken protein-based diet (CHPD) for 7 days, and characterized cecal microbiota composition and cecal gene expression. We found that a short-term intervention with a casein-based diet (CAD) induced a higher relative abundance of beneficial bacterium Lactococcus lactis as well as Bifidobacterium pseudolongum, which upregulated galactose metabolism of the microbiome compared with a CHPD. The CAD also upregulated gene expression involved in obesity associated pathways (e.g., Adipoq and Irs1) in cecal tissue of rats. These genes and the bacterial taxon were reported to play an important role in protecting development of obesity. Furthermore, the differentially represented bacterial taxon L. lactis was positively associated with these differentially expressed genes in the gut tissue. Our results provide a new insight into the crosstalk between gut microbiota and host in response to dietary proteins, indicating a potential mechanism of obesity prevention function by casein.

Proteomic analysis of sheep uterus reveals its role in prolificacy

Small Tail Han sheep have attracted attention for their high fecundity and year-round estrus. However, the molecular mechanisms of this fecundity are unknown. Polymorphism of the FecB gene has been shown to be associated with the ovulation rate and litter size in sheep. In this study, we used tandem mass tag quantitative proteomic techniques to identify the differentially abundant proteins in polytocous and monotocous Small Tail Han sheep (FecB++) uterine tissues in the follicular and luteal phases. In total, 41 and 43 differentially abundant proteins were identified in the follicular and luteal phases, respectively. Correlation analysis between the transcriptome and proteome revealed a positive correlation at the two omics levels of prolificacy. GO and KEGG pathway analyses indicated that the mRNAs and proteins upregulated in the polytocous group relative to the monotocous group are involved in sphingolipid metabolism and amino acid metabolism, and may be important in maintaining uterine functions and increasing the embryo survival rate during the estrus cycle of polytocous sheep. In conclusion, our work provides a prospective understanding of the molecular mechanism underlying the high prolificacy of Small Tail Han sheep. SIGNIFICANCE: Fecundity critically affects the profitability of sheep production, but the genetic mechanism of high-prolificacy is still unclear in sheep. We identified potential signaling pathways and differentially abundant proteins associated with reproductive performance through a combination of sheep uterus tissues proteome and transcriptome analyses. These findings will facilitate a better revealing the mechanism and provide possible targets for molecular design breeding for the formation of polytocous traits in sheep.

MicroRNAs mediate liver transcriptome changes upon soy diet intervention in mice

Soy‐based diets have triggered the interest of the research community due to their beneficial effects on a wide variety of pathologies like breast and prostate cancer, diabetes and atherosclerosis. However, the molecular details underlying these effects are far from being completely understood; several recent attempts have been made to elucidate the soy‐induced liver transcriptome changes in different animal models. Here we used Next Generation Sequencing to identify a set of microRNAs specifically modulated by short‐term soy‐enriched diet in young male mice and estimated their impact on the liver transcriptome assessed by microarray. Clustering and topological community detection (CTCD) network analysis of STRING generated interactions of transcriptome data led to the identification of four topological communities of genes characteristically altered and putatively targeted by microRNAs upon soy diet intervention.

Purified Dietary Red and White Meat Proteins Show Beneficial Effects on Growth and Metabolism of Young Rats Compared to Casein and Soy Protein

This study compared the effects of casein, soy protein (SP), red (RMP), and white meat (WMP) proteins on growth and metabolism of young rats. Compared to casein, the ratio of daily feed intake to daily body weight gain of rats was not changed by meat protein but reduced by SP by 93.3% ( P < 0.05). Feeding RMP and WMP reduced the liver total cholesterol (TC) contents by 24.3% and 17.8%, respectively ( P < 0.05). Only RMP increased plasma HDL-cholesterol concentrations (by 12.7%, P < 0.05), whereas SP increased plasma triacylglycerol, TC, and LDL-cholesterol concentrations by 23.7%, 19.5%, and 61.5%, respectively ( P < 0.05). Plasma essential and total amino acid concentrations were increased by WMP (by 18.8% and 12.4%, P < 0.05) but reduced by SP (by 28.3% and 37.7%, P < 0.05). Twenty-five liver proteins were differentially expressed in response to different protein sources. Therefore, meat proteins were beneficial for growth and metabolism of young rats compared to casein and SP.

Effects of Dietary Protein from Different Sources on Biotransformation, Antioxidation, and Inflammation in the Rat Liver

In this work, the effects of different sources of meat protein on liver metabolic enzymes were investigated. Rats were fed for 90 days with semisynthetic diets in which casein was fully replaced by isolated soybean, fish, chicken, pork, or beef proteins. Then, liver proteomics was performed using iTRAQ and LC-ESI-MS/MS. The results indicated that intake of meat protein diets significantly reduced the protein levels of CYP450s, GSTs, UGTs, and SULTs compared to those of the casein and soybean protein diet groups. The total antioxidant capacity and lipid peroxidation values did not differ between four meat protein diet groups and the casein diet group. However, GSH activity in the fish, chicken, and beef protein groups was significantly higher than those of the casein and soybean protein groups. The beef protein diet significantly upregulated the expression of immune-related proteins. The Keap1-Nrf2-ARE signaling pathway was suggested to involve the diet-mediated regulation of biotransformation, inflammation, and redox status.

TCA precipitation and ethanol/HCl single-step purification evaluation: One-dimensional gel electrophoresis, bradford assays, spectrofluorometry and Raman spectroscopy data on HSA, Rnase, lysozyme - Mascots and Skyline data

The data presented here are related to the research paper entitled "Study of a Novel Agent for TCA Precipitated Proteins Washing - Comprehensive Insights into the Role of Ethanol/HCl on Molten Globule State by Multi-Spectroscopic Analyses" (Eddhif et al., submitted for publication) [1]. The suitability of ethanol/HCl for the washing of TCA-precipitated proteins was first investigated on standard solution of HSA, cellulase, ribonuclease and lysozyme. Recoveries were assessed by one-dimensional gel electrophoresis, Bradford assays and UPLC-HRMS. The mechanistic that triggers protein conformational changes at each purification stage was then investigated by Raman spectroscopy and spectrofluorometry. Finally, the efficiency of the method was evaluated on three different complex samples (mouse liver, river biofilm, loamy soil surface). Proteins profiling was assessed by gel electrophoresis and by UPLC-HRMS.

Quantitative Proteomic Analysis of Changes Related to Age and Calorie Restriction in Rat Liver Tissue

Calorie restriction (CR) is the most frequently studied mechanism for increasing longevity, protecting against stress, and delaying age-associated diseases. Most studies have initiated CR in young animals to determine the protective effects against aging. Although aging phenomena are well-documented, the molecular mechanisms of aging and CR remain unclear. In this study, we observe changes in hepatic proteins upon age-related and diet-restricted changes in the rat liver using quantitative proteomics. Quantitative proteomes are measured using tandem mass tag labeling followed by LC-MS/MS. We compare protein levels in livers from young (6 months old) and old (25 months old) rats with 40% calorie-restricted (YCR and OCR, respectively) or ad libitum diets. In total, 44 279 peptides and 3134 proteins are identified and 260 differentially expressed proteins are found. Functional enrichment analysis show that these proteins are mainly involved in glucose and fatty acid metabolism-related processes, consistent with the theory that energy metabolism regulation is dependent on age-related and calorie-restricted changes in liver tissue. In addition, proteins mediating inflammation and gluconeogenesis are increased in OCR livers, but not YCR livers. These results show that CR in old rats might not have antiaging benefits because liver inflammation is increased.

Proteome Analysis Using Isobaric Tags for Relative and Absolute Analysis Quantitation (iTRAQ) Reveals Alterations in Stress-Induced Dysfunctional Chicken Muscle

The current study was designed to investigate changes in the protein profiles of pale, soft, and exudative (PSE)-like muscles of broilers subjected to transportation under high-temperature conditions, using isobaric tags for relative and absolute analysis quantitation (iTRAQ). Arbor Acres chickens (n = 112) were randomly divided into two treatments: unstressed control (CON) and 0.5 h of transport (T). Birds were transported according to a designed protocol. Pectoralis major (PM) muscle samples in the T group were collected and classified as normal (T-NOR) or PSE-like (T-PSE). Plasma activities of stress indicators, muscle microstructure, and proteome were measured. Results indicated that broilers in the T-PSE group exhibited higher activities of plasma stress indicators. The microstructure of T-PSE group showed a looser network and larger intercellular spaces in comparison to the other groups. Proteomic analysis, based on iTRAQ, revealed 29 differentially expressed proteins in the T-NOR and T-PSE groups that were involved in protein turnover, signal transduction, stress and defense, calcium handling, cell structure, and metabolism. In particular, proteins relating to the glycolysis pathway, calcium signaling, and molecular chaperones exhibited significant differences that may contribute to the inferior post-mortem meat quality. Overall, the proteomic results provide a further understanding of the mechanism of meat quality changes in response to stress.

Animal Proteins as Important Contributors to a Healthy Human Diet

Adequate protein intake is critical for health and development. Generally, protein of animal origin is of higher quality for humans owing to its amino acid pattern and good digestibility. When administered in mixtures it can enhance the quality of plant proteins, but its availability is often low in low-income communities, especially in young children, the elderly, and pregnant and lactating women, who have increased requirements and in whom high-quality protein also stimulates (bone) growth and maintenance. Although high protein intake was associated with increased type 2 diabetes mellitus risk, milk and seafood are good sources of branched chain amino acids and taurine, which act beneficially on glucose metabolism and blood pressure. However, high consumption of protein-rich animal food is also associated with adverse health effects and higher risk for noncommunicable diseases, partly related to other components of these foods, like saturated fatty acids and potential carcinogens in processed meat but also the atherogenic methionine metabolite homocysteine. In moderation, however, animal proteins are especially important for health maintenance in vulnerable persons.

Identifying Virulence-Associated Genes Using Transcriptomic and Proteomic Association Analyses of the Plant Parasitic Nematode Bursaphelenchus mucronatus

Bursaphelenchus mucronatus (B. mucronatus) isolates that originate from different regions may vary in their virulence, but their virulence-associated genes and proteins are poorly understood. Thus, we conducted an integrated study coupling RNA-Seq and isobaric tags for relative and absolute quantitation (iTRAQ) to analyse transcriptomic and proteomic data of highly and weakly virulent B. mucronatus isolates during the pathogenic processes. Approximately 40,000 annotated unigenes and 5000 proteins were gained from the isolates. When we matched all of the proteins with their detected transcripts, a low correlation coefficient of r = 0.138 was found, indicating probable post-transcriptional gene regulation involved in the pathogenic processes. A functional analysis showed that five differentially expressed proteins which were all highly expressed in the highly virulent isolate were involved in the pathogenic processes of nematodes. Peroxiredoxin, fatty acid- and retinol-binding protein, and glutathione peroxidase relate to resistance against plant defence responses, while β-1,4-endoglucanase and expansin are associated with the breakdown of plant cell walls. Thus, the pathogenesis of B. mucronatus depends on its successful survival in host plants. Our work adds to the understanding of B. mucronatus' pathogenesis, and will aid in controlling B. mucronatus and other pinewood nematode species complexes in the future.