Revealing the diversity of endogenous peptides and parent proteins in human colostrum and mature milk through peptidomics analysis.

Endogenous peptides and their parent proteins are important nutritional components with diverse biological functions. The objective of this study was to analyze and compare endogenous peptides and parent proteins found in human colostrum (HC) and human mature milk (HM) using a 4D label-free technique. In total, 5162 and 940 endogenous peptides derived from 258 parent proteins were identified in human milk by database (DB) search and de novo, respectively. Among these peptides, 2446 differentially expressed endogenous peptides with various bioactivities were identified. The Gene Ontology analysis unveiled the cellular components, biological processes, and molecular functions associated with these parent proteins. Metabolic pathway analysis suggested that neutrophil extracellular trap formation had the greatest significance with 24 parent proteins. These findings will offer a fresh perspective on the development of infant formula powder, highlighting the potential for incorporating these changes to enhance its nutritional composition and benefits.

Proteomics and Metabolomics Analysis Reveal the Regulation Mechanism of Linoleate Isomerase Activity and Function in Propionibacterium acnes.

Conjugated linoleic acid (CLA) holds significant application prospects due to its anticancer, anti-atherosclerosis, lipid-lowering, weight-loss, and growth-promoting functions. The key to its efficient production lies in optimizing the biocatalytic performance of linoleic acid isomerase (LAI). Here, we constructed a Propionibacterium acnes mutant library and screened positive mutants with high linoleate isomerase activity. The proteomics and metabolomics were used to explore the mechanism in the regulation of linoleic acid isomerase activity. High-throughput proteomics revealed 104 differentially expressed proteins unique to positive mutant strains of linoleic acid isomerase of which 57 were upregulated and 47 were downregulated. These differentially expressed proteins were primarily involved in galactose metabolism, the phosphotransferase system, starch metabolism, and sucrose metabolism. Differential metabolic pathways were mainly enriched in amino acid biosynthesis, including glutamate metabolism, the Aminoacyl-tRNA biosynthesis pathway, and the ABC transporter pathway. The upregulated metabolites include dl-valine and Acetyl coA, while the downregulated metabolites include Glutamic acid and Phosphoenolpyruvate. Overall, the activity of linoleic acid isomerase in the mutant strain was increased by the regulation of key proteins involved in galactose metabolism, sucrose metabolism, and the phosphotransferase system. This study provides a theoretical basis for the development of high-yield CLA food.

Proteomics and Peptidomics As a Tool to Compare the Proteins and Endogenous Peptides in Human, Cow, and Donkey Milk.

Cow's milk is the most widely used ingredient in infant formulas. However, its specific protein composition can cause allergic reactions. Finding alternatives to replace cow's milk and fill the nutritional gap with human milk is essential for the health of infants. Proteomic and peptidomic techniques have supported the elucidation of milk's nutritional ingredients. Recently, omics approaches have attracted increasing interest in the investigation of milk because of their high throughput, precision, sensitivity, and reproducibility. This review offers a significant overview of recent developments in proteomics and peptidomics used to study the differences in human, cow, and donkey milk. All three types of milks were identified to have critical biological functions in human health, particularly in infants. Donkey milk proteins were closer in composition to human milk, were less likely to cause allergic reactions, and may be developed as novel raw materials for formula milk powders.

Characterization and biological function analysis of endogenous peptides derived from donkey colostrum proteins.

Donkey colostrum, due to its abundance of active ingredients, including lysozyme, proteins, and peptides, is essential for the growth and immune defence of newborns. However, research on endogenous peptides in donkey colostrum is inadequate. This study analysed the profiles of endogenous peptides, their potential bioactivity, and the enzymes that generated these peptides using two different strategies. A total of 6202 endogenous peptides were characterised through a database search, while an additional 2997 peptides were identified de novo. Among the 1142 proteins identified, trypsin and plasmin demonstrated the highest bioactivities. Furthermore, a bioinformatics-based screening identified antioxidant peptides, angiotensin I-converting enzyme inhibitory peptides, and dipeptidyl peptidase IV inhibitory peptides as the three most active peptides. Gene Ontology (GO) annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were conducted. These findings enhance our knowledge of endogenous peptides in donkey colostrum and provide crucial information regarding these peptides as nutritional factors for the future development of functional foods derived from donkey sources.

Pilose antler polypeptides enhance chemotherapy effects in triple-negative breast cancer by activating the adaptive immune system.

Water-soluble polypeptides from pilose antler (PAWPs) are a traditional Chinese functional food and have been reported to inhibit triple-negative breast cancer (TNBC) in mice. Thus, in this study, we characterized PAWPs through peptidomics, and 405 total polypeptides were finally identified. Subsequently, our results indicate that PAWPs combined with neoadjuvant chemotherapy (NAC) result in a markedly lower spleen index compared with that in other groups. Next, 25 subpopulations of T cells were identified by multi-parametric flow cytometry in the lungs, spleen, and peripheral blood of different groups. These results indicated that PAWPs combined with NAC promote the proliferation of CD3+ T cells in the spleen and significantly affect the fate of the T-cell subpopulation. Moreover, PAWPs combined with NAC increased the infiltration of CD4+ interferon-γ+ T cells into tumor tissues. Our results showed that PAWPs have immunoregulatory functions and chemosensitizing effects, with good prospects for future clinical application.