Peptidome analysis of human skim milk in term and preterm milk

MDPAO1 peptide from human milk enhances brown adipose tissue thermogenesis and mitigates obesity

The regulatory effect of breastfeeding on offspring metabolism has garnered significant attention as an effective strategy in combating childhood obesity. However, the underlying mechanism remains largely unknown. Through integrated analysis of multiple human milk peptide databases and functional screening, MDPAO1 (milk-derived peptide associated with obesity 1) was identified as having potential activity in promoting the expression of thermogenic genes. In lactating mice, intervention with MDPAO1 enhanced the thermogenic phenotype of brown adipose tissue (BAT) and overall metabolic activity. Moreover, MDPAO1 intervention led to reduced body weight gain, increased brown fat mass, and improved glucose tolerance and insulin sensitivity in a mouse model of high-fat diet (HFD)-induced obesity. RNA-seq analysis of BAT post-MDPAO1 intervention revealed close association with mitochondrial oxidative respiratory chain and mitophagy. Subsequent in vitro experiments conducted on primary brown adipocytes confirmed that MDPAO1 inhibited mitophagy, increased mitochondrial mass, and elevated levels of mitochondrial respiratory chain complexes. In conclusion, this study underscores the potential of MDPAO1, a peptide enriched in breast milk, in activating the thermogenic phenotype of brown adipose tissue and mitigating obesity, thus offering novel insights into the mechanisms underlying breastfeeding's role in preventing childhood obesity.

Human Milk Protein-Derived Bioactive Peptides from In Vitro-Digested Colostrum Exert Antimicrobial Activities against Common Neonatal Pathogens

Human milk reduces risk for necrotizing enterocolitis in preterm infants. Necrotizing enterocolitis occurs in the ileocecal region where thousands of milk protein-derived peptides have been released from digestion. Digestion-released peptides may exert bioactivity, such as antimicrobial and immunomodulatory activities, in the gut. In this study, we applied mass spectrometry-based peptidomics to characterize peptides present in colostrum before and after in vitro digestion. Sequence-based computational modeling was applied to predict peptides with antimicrobial activity. We identified more peptides in undigested samples, yet the abundances were much higher in the digested samples. Heatmapping demonstrated highly different peptide profiles between undigested and digested samples. Four peptides (αS1-casein [157-163], αS1-casein [157-165], β-casein [153-159] and plasminogen [591-597]) were selected, synthesized and tested against common pathogenic bacteria associated with necrotizing enterocolitis. All four exhibited bacteriostatic, though not bactericidal, activities against Klebsiella aerogenes, Citrobacter freundii and Serratia marcescens, but not Escherichia coli.

Antimicrobial Peptides (AMPs) and the Microbiome in Preterm Infants: Consequences and Opportunities for Future Therapeutics

Antimicrobial peptides (AMPs) are crucial components of the innate immune system in various organisms, including humans. Beyond their direct antimicrobial effects, AMPs play essential roles in various physiological processes. They induce angiogenesis, promote wound healing, modulate immune responses, and serve as chemoattractants for immune cells. AMPs regulate the microbiome and combat microbial infections on the skin, lungs, and gastrointestinal tract. Produced in response to microbial signals, AMPs help maintain a balanced microbial community and provide a first line of defense against infection. In preterm infants, alterations in microbiome composition have been linked to various health outcomes, including sepsis, necrotizing enterocolitis, atopic dermatitis, and respiratory infections. Dysbiosis, or an imbalance in the microbiome, can alter AMP profiles and potentially lead to inflammation-mediated diseases such as chronic lung disease and obesity. In the following review, we summarize what is known about the vital role of AMPs as multifunctional peptides in protecting newborn infants against infections and modulating the microbiome and immune response. Understanding their roles in preterm infants and high-risk populations offers the potential for innovative approaches to disease prevention and treatment.

Gestational age at birth influences protein and RNA content in human milk extracellular vesicles

Human milk extracellular vesicles (HM EVs) are proposed to protect against disease development in infants. This protection could in part be facilitated by the bioactive EV cargo of proteins and RNA. Notably, mothers birth infants of different gestational ages with unique needs, wherein the EV cargo of HM may diverge. We collected HM from lactating mothers within two weeks of a term or preterm birth. Following purification of EVs, proteins and mRNA were extracted for proteomics and sequencing analyses, respectively. Over 2000 protein groups were identified, and over 8000 genes were quantified. The total number of proteins and mRNA did not differ significantly between the two conditions, while functional bioinformatics of differentially expressed cargo indicated enrichment in immunoregulatory cargo for preterm HM EVs. In term HM EVs, significantly upregulated cargo was enriched in metabolism-related functions. Based on gene expression signatures from HM-contained single cell sequencing data, we proposed that a larger portion of preterm HM EVs are secreted by immune cells, whereas term HM EVs contain more signatures of lactocyte epithelial cells. Proposed differences in EV cargo could indicate variation in mother's milk based on infants' gestational age and provide basis for further functional characterisation.

Combining in silico and in vitro approaches to identify endogenous hypoglycemic peptides from human milk

Potential endogenous hypoglycemic peptides derived from breast milk were screened by in silico approaches against intestinal glucose absorption- and metabolism-related membrane proteins (i.e., SGLT1, ATPase, and GPR40), and their inhibitory...

Monitoring Human Milk β-Casein Phosphorylation and O-Glycosylation Over Lactation Reveals Distinct Differences between the Proteome and Endogenous Peptidome

Human milk is a vital biofluid containing a myriad of molecular components to ensure an infant's best start at a healthy life. One key component of human milk is β-casein, a protein which is not only a structural constituent of casein micelles but also a source of bioactive, often antimicrobial, peptides contributing to milk's endogenous peptidome. Importantly, post-translational modifications (PTMs) like phosphorylation and glycosylation typically affect the function of proteins and peptides; however, here our understanding of β-casein is critically limited. To uncover the scope of proteoforms and endogenous peptidoforms we utilized mass spectrometry (LC-MS/MS) to achieve in-depth longitudinal profiling of β-casein from human milk, studying two donors across 16 weeks of lactation. We not only observed changes in β-casein's known protein and endogenous peptide phosphorylation, but also in previously unexplored O-glycosylation. This newly discovered PTM of β-casein may be important as it resides on known β-casein-derived antimicrobial peptide sequences.

[Effect of sample preparation on analysis of human milk endogenous peptides using liquid chromatography-tandem mass spectrometry]

人乳内源肽是乳蛋白在乳腺中被降解形成的具有生理功能的肽,是人乳的重要组成部分,研究人乳内源肽对于婴儿健康具有重要的意义。高效液相色谱-串联质谱(LC-MS/MS)联用技术的应用,促使人乳内源肽的研究取得了突破性的进展。人乳中内源肽含量低、干扰组分多,样品制备方法是影响分析结果的关键步骤。为了研究样品制备方法对分析结果的影响,分别采用不变性超滤法(UF 1)、热变性超滤法(UF 2)、化学变性超滤法(UF 3)、三氯乙酸沉淀法(PCPN 1)、乙醇沉淀法(PCPN 2)、强疏水性碳介孔材料(highly ordered mesoporous carbon, OMC)富集法等6种方法从人乳中提取内源肽,利用LC-MS/MS研究样品制备方法对人乳内源肽分析结果的影响。结果表明,UF 1和UF 2法制备的样品中可鉴定到的肽段数目分别为1161±8条和1017±91条,两种方法制备的样品中肽序列的重合率大于70%, UF 1在所有方法中鉴定到的肽的数目最多。UF 3法制备的样品所能鉴定到的肽段数目最少,仅为366±18条。PCPN 1和PCPN 2两种沉淀法制备样品中的内源肽分别为779±69和876±55条,但内源肽差异较大,仅有约50%肽段序列重合。OMC法制备样品中肽的数目为549±151条,与其他方法相比,虽然鉴定的肽数量上没有优势,但该方法制备的样品中肽在等电点(pI)和亲水性平均系数(GRAVY)等性质上没有偏倚,说明该法可用于制备特定人乳内源肽。6种方法制备的样品中鉴定到来源于β-酪蛋白、免疫球蛋白受体、骨桥蛋白、α_S1-酪蛋白、κ-酪蛋白和胆盐激活脂肪酶的肽,并且源于以上蛋白质的肽段总数在该样品中均超过88%,说明6种方法制备的样品都可以满足鉴定一般人乳内源肽的需求。UF 2、UF 3和OMC法制备的样品中鉴定到源于乳铁蛋白的内源肽的数目分别为21、38和19条,内源肽在乳铁蛋白上的覆盖率分别为14%、16%和19%,而文献常用的PCPN 1法制备的样品则会丢失此类内源肽。综上,UF 2法制备的样品不仅肽段数量多、母体蛋白质种类丰富,还可鉴定到源于乳铁蛋白的肽,可作为人乳内源肽组学研究中的首选方法。

A Novel Anti-Infective Peptide BCCY-1 With Immunomodulatory Activities

Antibiotic resistance has been considered to be a global threat which underscores the need to develop novel anti-infective therapeutics. Modulation of innate immunity by synthetic peptides is an attractive strategy to overcome this circumstance. We recently reported that BCCY-1, a human β-casein-derived peptide displays regulatory activities on monocytes, thereby enhancing their actions in innate immune responses. However, the function of peptide BCCY-1 in host defense against infection remains unknown. In this study, we investigated the in vivo characteristics and effects of peptide BCCY-1 in mouse models of bacterial infection. Following intraperitoneal injection, the peptide BCCY-1 exhibited high level of cellular uptake by monocytes without obvious toxicities. Results revealed that peptide BCCY-1, but not the scrambled version, stimulated the chemokine production and monocyte recruitment in vivo. Treatment with BCCY-1 enhanced the pathogen clearance and protected mice against lethal infections. Because the anti-infective effects of BCCY-1 was abolished by in vivo depletion of monocytes/macrophages rather than lymphocytes and granulocytes, we conclude that monocytes/macrophages are key effector cells in BCCY-1-mediated anti-infective protection. Additionally, BCCY-1 lacks direct antimicrobial activity. To our knowledge, a human β-casein-derived peptide that counters infection by selective regulation of innate immunity has not been reported previously. These results suggest peptide BCCY-1 as a promising alternative approach and a valuable complement to current anti-infective strategy.

A human β-casein-derived peptide BCCY-1 modulates the innate immune response

In this study, we report a novel peptide corresponding to the sequence of human β-casein (named BCCY-1), which was identified in our previous peptidome analysis of human milk and has great immunomodulatory activity. The results revealed that peptide BCCY-1, but not the scrambled version, enhanced monocyte migration without obvious toxicities. This selective effect was mediated via increased production of chemokines by peptide stimulated monocytes. Moreover, BCCY-1 exerted its modulatory effects by activating nuclear factor (NF)-κB and mitogen-activated protein kinase (MAPK) signaling. The abundances of peptide BCCY-1 and the peptides partially encompassing its fragment were found to be lower in preterm milk than in term milk. Our study may lead to new insights into the immunoregulatory effects of casein-derived peptides and facilitate the discovery of novel peptide-based food and pharmaceutical products.

A novel endogenous antimicrobial peptide CAMP211-225 derived from casein in human milk

A large number of bioactive peptides derived from breast milk have been identified to be multifunctional having anti-inflammatory, immunoregulatory and antimicrobial activities. Here, we report that an endogenous peptide located at β-casein 211-225 amino acid from human breast milk (hereafter called CAMP211-225) presents specific antimicrobial activity against pathogenic E. coli and Y. enterocolitica. CAMP211-225 is a novel peptide that occurs at higher levels in preterm milk than in term milk. The minimal inhibitory concentrations (MIC) of CAMP211-225 against E. coli and Y. enterocolitica are 3.125 μg ml-1 and 6.25 μg ml-1, respectively, and the antimicrobial activity of CAMP211-225 was also confirmed by a disk diffusion assay. Further studies using fluorescence staining, scanning electron microscopy and a DNA-binding assay revealed that CAMP211-225 kills bacteria through a membrane-disrupting mechanism, but not by binding to intracellular nucleic acids. Neonatal necrotizing enterocolitis (NEC) is a devastating gastrointestinal disease in neonatal intensive care units. In our study, CAMP211-225 administration effectively reduced ileal mucosa damage in an experimental NEC mice model. These results suggest that the antimicrobial peptide CAMP211-225 may have potential value in the prevention and treatment of neonatal infections.

Human milk derived peptide AOPDM1 attenuates obesity by restricting adipogenic differentiation through MAPK signalling

BACKGROUND

Emerging evidence revealed peptides within breast milk may be an abundant source of potential candidates for metabolism regulation. Our previous work identified numerous peptides existed in breast milk, but its function has not been validated. Thus, our study aims to screen for novel peptides that have the potential to antagonize obesity and diabetes.

METHODS

A function screen was designed to identify the candidate peptide and then the peptide effect was validated by assessing lipid storage. Afterwards, the in vivo study was performed in two obese models: high-fat diet (HFD)-induced obese mice and obese ob/ob mice. For mechanism study, a RNA-seq analysis was conducted to explore the pathway that account for the biological function of peptide.

RESULTS

By performing a small scale screening, a peptide (AVPVQALLLNQ) termed AOPDM1 (anti-obesity peptide derived from breast milk 1) was identified to reduce lipid storage in adipocytes. Further study showed AOPDM1 suppressed adipocyte differentiation by sustaining ERK activity at later stage of differentiation which down-regulated PPARγ expression. In vivo, AOPDM1 effectively reduced fat mass and improved glucose metabolism in high-fat diet (HFD)-induced obese mice and obese ob/ob mice.

CONCLUSIONS

We identified a novel peptide AOPDM1 derived from breast milk could restrict adipocyte differentiation and ameliorate obesity through regulating MAPK pathway.

GENERAL SIGNIFICANCE

Our findings may provide a potential candidate for the discovery of therapeutic drugs for obesity and type 2 diabetes.

Differences in human milk peptide release along the gastrointestinal tract between preterm and term infants

BACKGROUND & AIMS

Preterm infants are born with a gastrointestinal tract insufficiently developed to digesting large quantities of human milk proteins. Peptides released from the digestion of human milk proteins have been identified with bioactivities that may be beneficial to the developing infant. However, it is unknown how prematurity affects total and bioactive peptide release along the gastrointestinal tract. The aim of this study was to compare milk peptide release from milk to stomach to stool between preterm and term infants.

METHODS

Milk, gastric, and stool samples were collected from preterm infants as early collection (days 8 and 9 of life) and late collection (days 21 and 22 of life), and from term infants as early collection. Milk peptides were extracted from the samples and identified using Orbitrap mass spectrometry. Peptide abundance and count were compared across digestion and between the three infant groups at each stage of digestion.

RESULTS

Total milk peptide count and abundance increased from milk to stomach then decreased in stool. Total peptide release was similar among the three infant groups for milk and stool samples. In the stomach, preterm early collection had significantly higher peptide abundance and count than the other two groups. Patterns for peptide release from individual milk proteins were distinct from total peptide release both across digestion and among the infant groups. When analyzing single peptides, term early collection gastric samples had significantly higher peptide abundance than preterm early collection for a known antimicrobial peptide, QELLLNPTHQIYPVTQPLAPVHNPISV.

CONCLUSIONS

Preterm and term infants digest milk proteins differently along their gastrointestinal tracts. While preterm infants released more total peptides in the stomach, term infants released specific bioactive peptides at higher abundance. We identified a region at the C-terminus of β-casein that is conserved from milk through stool and from which are released known and potential antimicrobial peptides.

The Functional Power of the Human Milk Proteome

Human milk is the most complete and ideal form of nutrition for the developing infant. The composition of human milk consistently changes throughout lactation to meet the changing functional needs of the infant. The human milk proteome is an essential milk component consisting of proteins, including enzymes/proteases, glycoproteins, and endogenous peptides. These compounds may contribute to the healthy development in a synergistic way by affecting growth, maturation of the immune system, from innate to adaptive immunity, and the gut. A comprehensive overview of the human milk proteome, covering all of its components, is lacking, even though numerous analyses of human milk proteins have been reported. Such data could substantially aid in our understanding of the functionality of each constituent of the proteome. This review will highlight each of the aforementioned components of human milk and emphasize the functionality of the proteome throughout lactation, including nutrient delivery and enhanced bioavailability of nutrients for growth, cognitive development, immune defense, and gut maturation.

Profiling Analysis Reveals the Potential Contribution of Peptides to Human Adipocyte Differentiation

PURPOSE

Peptide drugs provide promising regimes in anti-obesity treatment. In order to identify potential bioactive peptides involved in adipogenesis.

EXPERIMENTAL DESIGN

The intracellular peptides between preadipocytes and adipocytes are compared by liquid chromatography/mass spectrometry. The underlying biological function of the identified peptides are evaluated by gene ontology (GO) and pathway analysis of their precursors. To find more potential bioactive peptides, 50 peptide sequences are identified located in the functional domains with the use of the SMART and UniProt databases. Finally, the Open Targets Platform database is used to investigate the precursors related to metabolic diseases.

RESULTS

A total of 181 downregulated peptides and 89 upregulated peptides after differentiation (fold change > 1.5 and p-value < 0.05) are identified. The GO and pathway analysis indicate that these differentially expressed peptides play a role in adipogenesis. A total of 10 putative peptides 6 to 26 amino acids in length are identified that might have bioactive effects in adipogenesis and metabolic diseases.

CONCLUSIONS AND CLINICAL RELEVANCE

On one hand, present preliminary research provides a better understanding of the intracellular peptides during adipocyte differentiation. On the other hand, it lays a foundation for discovering new peptide drugs in anti-obesity treatment.

Human milk peptides differentiate between the preterm and term infant and across varying lactational stages

Variations in endogenous peptide profiles, functionality, and the enzymes responsible for the formation of these peptides in human milk are understudied. Additionally, there is a lack of knowledge regarding peptides in donor human milk, which is used to feed preterm infants when mother's own milk is not (sufficiently) available. To assess this, 29 human milk samples from the Dutch Human Milk Bank were analyzed as three groups, preterm late lactation stage (LS) (n = 12), term early (n = 8) and term late LS (n = 9). Gestational age (GA) groups were defined as preterm (24-36 weeks) and term (≥37 weeks). LS was determined as days postpartum as early (16-36 days) or late (55-88 days). Peptides, analyzed by LC-MS/MS, and parent proteins (proteins from matched peptide sequences) were identified and quantified, after which peptide functionality and the enzymes responsible for protein cleavage were determined. A total of 16 different parent proteins were identified from human milk, with no differences by GA or LS. We identified 1104 endogenous peptides, of which, the majority were from the parent proteins β-casein, polymeric immunoglobulin receptor, α_s1-casein, osteopontin, and κ-casein. The absolute number of peptides differed by GA and LS with 30 and 41 differing sequences respectively (p < 0.05) Odds likelihood tests determined that 32 peptides had a predicted bioactive functionality, with no significant differences between groups. Enzyme prediction analysis showed that plasmin/trypsin enzymes most likely cleaved the identified human milk peptides. These results explain some of the variation in endogenous peptides in human milk, leading to future targets that may be studied for functionality.

Discovery of Antimicrobial Peptides in Cervical-Vaginal Fluid from Healthy Nonpregnant Women via an Integrated Proteome and Peptidome Analysis

Cervical-vaginal fluid (CVF) covers the lower part of the female reproductive system and functions in the homeostasis and immunity of the surrounding tissues. In contrast to the CVF proteome of both nonpregnant and pregnant women, the CVF peptidome has not been reported to date. In the current study, we identified 1087 proteins in CVF, of which 801 proteins were not previously identified in CVF proteomes. The presence of the tissue-specific proteins oviductal glycoprotein 1 and tubulin polymerization-promoting protein family member 3 strongly suggests that the tissues of the upper female reproductive tract contribute to the protein composition of CVF. The tremendous catalytic potential of CVF was highlighted by the identification of 85 proteases and the detection of pH-dependent trypsin-like proteolytic activity. Over 1000 endogenous peptides were detected in the CVF peptidome, and 39 peptides are predicted to have antimicrobial activity. The detailed proteomic and peptidomic analysis of CVF will further aid in the delineation of pathways related to reproduction, immunity and host defense, and assist in developing new biomarkers for malignant and other diseases of the female reproductive tract. Data are available via ProteomeXchange with identifiers PXD004450 (CVF peptidome) and PDX004363 (CVF proteome).

Peptidome analysis of amniotic fluid from pregnancies with preeclampsia

Preeclampsia (PE), a life-threatening, complicated pregnancy-associated disease, has recently become a research focus in obstetrics. However, the peptidome of the amniotic fluid in PE patients has rarely been investigated. The present study used peptidomic profiling to perform a comparative analysis of human amniotic fluid between normal and PE pregnancies. Centrifugal ultrafiltration and liquid chromatography-tandem mass spectrometry (LC-MS/MS) was combined with isotopomeric dimethyl labels to gain a deeper understanding of the role of proteins and the peptidome in the onset of PE. Following ultrafiltration and LC-MS/MS, 352 peptides were identified. Of these, 23 peptides were observed to be significantly differentially expressed (6 downregulated and 17 upregulated; P<0.05). Using Gene Ontology and Blastp analyses, the functions and biological activities of these 23 peptides were identified and revealed to include autophagy, signal transduction, receptor activity, enzymatic activity and nucleic acid binding. In addition, a bibliographic search revealed that some of the identified peptides, including Titin, are crucial to the pathogenesis underlying PE. The present study identified 23 peptides expressed at significantly different levels in the amniotic fluid of PE and normal pregnancies. A comprehensive peptidome analysis is more efficient than a simple biomarker analysis at revealing deficiencies and improving the detection rate in diseases. These analyses therefore provide a substantial advantage in applications aimed at the discovery of disease-specific biomarkers.

Antimicrobial activity and mechanism of the human milk-sourced peptide Casein201

INTRODUCTION

Casein201 is one of the human milk sourced peptides that differed significantly in preterm and full-term mothers. This study is designed to demonstrate the biological characteristics, antibacterial activity and mechanisms of Casein201 against common pathogens in neonatal infection.

METHODOLOGY

The analysis of biological characteristics was done by bioinformatics. Disk diffusion method and flow cytometry were used to detect the antimicrobial activity of Casein201. Killing kinetics of Casein201 was measured using microplate reader. The antimicrobial mechanism of Casein201 was studied by electron microscopy and electrophoresis.

RESULTS

Bioinformatics analysis indicates that Casein201 derived from β-casein and showed significant sequence overlap. Antibacterial assays showed Casein201 inhibited the growth of S taphylococcus aureus and Y ersinia enterocolitica. Ultrastructural analyses revealed that the antibacterial activity of Casein201 is through cytoplasmic structures disintegration and bacterial cell envelope alterations but not combination with DNA.

CONCLUSION

We conclude the antimicrobial activity and mechanism of Casein201. Our data demonstrate that Casein201 has potential therapeutic value for the prevention and treatment of pathogens in neonatal infection.

Antimicrobial activity and mechanism of PDC213, an endogenous peptide from human milk

Human milk has always been considered an ideal source of elemental nutrients to both preterm and full term infants in order to optimally develop the infant's tissues and organs. Recently, hundreds of endogenous milk peptides were identified in human milk. These peptides exhibited angiotensin-converting enzyme inhibition, immunomodulation, or antimicrobial activity. Here, we report the antimicrobial activity and mechanism of a novel type of human antimicrobial peptide (AMP), termed PDC213 (peptide derived from β-Casein 213-226 aa). PDC213 is an endogenous peptide and is present at higher levels in preterm milk than in full term milk. The inhibitory concentration curve and disk diffusion tests showed that PDC213 had obvious antimicrobial against S. aureus and Y. enterocolitica, the common nosocomial pathogens in neonatal intensive care units (NICUs). Fluorescent dye methods, electron microscopy experiments and DNA-binding activity assays further indicated that PDC213 can permeabilize bacterial membranes and cell walls rather than bind intracellular DNA to kill bacteria. Together, our results suggest that PDC213 is a novel type of AMP that warrants further investigation.

Peptidome profiling of umbilical cord plasma associated with gestational diabetes-induced fetal macrosomia

Fetal macrosomia, defined as a birth weight ≥4000g, may affect 15-45% of newborns of women with gestational diabetes mellitus (GDM). The associations between endogenous peptides and gestational diabetes-induced macrosomia have not been investigated extensively by peptidome analysis. Here, we analyzed the umbilical cord plasma by combining ultrafiltration using molecular weight cut-off filters and liquid chromatography-tandem mass spectrometry (LC-MS/MS) to investigate potential associations of GDM with macrosomia. As macrosomic babies have increased susceptibility to obesity, diabetes and cardiovascular diseases in later life, we also aimed to identify specific biomarkers to detect these future diseases. Thirty pairs of GDM mothers and controls were randomly divided into three subgroups. We identified 235 peptides of around 1000-3000Da, originating from 115 proteins. Analyzing the cleavage sites revealed that these peptides were cleaved in regulation, which may reflect the protease activity and distribution in umbilical cord plasma. Four identified peptides, of 2471.7, 1077.2, 1446.5 and 2372.7Da, were significantly differentially expressed in the GDM macrosomia groups compared with controls, whose precursors may play a critical role in developing GDM macrosomia. We provide for the first time a validated GDM macrosomia peptidome profile and identify potential biomarkers linking the effects of macrosomia to later-life diseases.

BIOLOGICAL SIGNIFICANCE

Fetal macrosomia is the predominant adverse outcome of gestational diabetes mellitus (GDM), which is a frequent medical condition during pregnancy. Till now, the detailed molecular mechanisms underlying gestational diabetes-induced macrosomia are still not elucidated. With high detection sensitivity and high throughput of peptidome technology, it is now possible to systemically identify peptides possibly involved in the umbilical cord plasma of GDM induced macrosomia cases. With LC-MS/MS based quantification, totally, we identified 235 peptides originated from 115 precursor proteins. And four peptides of 2471.7, 1077.2, 1446.5 and 2372.7Da differentially expressed between GDM cases and compared controls. A precursor protein of 1077.2Da was fibrinogen alpha chain (FGA), which was also identified in the Ai et al. [29] study with a downregulated manner in the serum samples of GDM cases. And further analysis the cleavage pattern of the identified peptides revealed that the enzymes in tissues cleaved the protein according to their rules. Thus, this quantitative peptidome approach can identify related peptides that may play a role in the gestational diabetes-induced macrosomia, and give candidate biomarkers contributing to the development of later-life diseases in macrosomic babies.

Recent applications of CE- and HPLC-MS in the analysis of human fluids

The present review intends to cover the literature on the use of CE-/LC-MS for the analysis of human fluids, from 2010 until present. It has been planned to provide an overview of the most recent practical applications of these techniques to less extensively used human body fluids, including, bronchoalveolar lavage fluid, synovial fluid, nipple aspirate, tear fluid, breast fluid, amniotic fluid, and cerumen. Potential pitfalls related to fluid collection and sample preparation, with particular attention to sample clean-up procedures, and methods of analysis, from the research laboratory to a clinical setting will also be addressed. While being apparent that proteomics/metabolomics represent the most prominent approaches for global identification/quantification of putative biomarkers for a variety of human diseases, evidence is also provided of the suitability of these sophisticated techniques for the detection of heterogeneous components carried by these fluids.

Clustering analyses in peptidomics revealed that peptide profiles of infant formulae are descriptive

Prompted by the accumulating evidence on bioactive moieties of milk-derived peptides, novel methods were applied to compare the peptide composition among commercially available hydrolysate formulations and to determine batch-to-batch variations of protein hydrolysate products. Despite the availability of general methods to measure, for example, the degree of hydrolysis and peptide mass distribution at a high level, the objective of this study was to more qualitatively compare peptide sequences and composition. By a comprehensive approach combining peptidomics technologies and multivariate clustering analyses, the peptide profiles of different hydrolyzed milk protein formulations were compared. Moreover, peptide profiles of various hydrolysate batches that had been produced over a period of 5 years were included. Coupling of identified peptide sequences to the position in their corresponding milk proteins produced numerical datasets that subsequently were utilized for multivariate data analyses. These analyses revealed that batch-to-batch variation in the peptide profiles of a specific extensively hydrolyzed casein preparation was low. Moreover, extensive multivariate evaluations revealed that the peptide profiles of different commercially available hydrolyzed milk protein formulations provided a descriptive and distinct signature. Overall, the described methodology may contribute to the field of peptide research as observed dissimilarities in peptide profiles of similar products may be related to differences in their overall functionality.

Peptidomics study of anthocyanin-rich juice of elderberry

Biologically active peptides play a role in plant signaling and defense. Elderberry juice is known to contain a variety of anthocyanin compounds, a sub-set of polyphenols, which are responsible for the deep purple color of the juice. In this paper, we describe a method utilizing solid phase extraction (SPE) to remove anthocyanins from peptides. Liquid chromatography coupled with tandem mass spectrometry was used to separate and identify the peptides. The results showed that the use of SPE was an effective method to separate peptides from anthocyanins and other background compounds including high polyphenol content in the juice samples. More than 1000 peptides present in elderberry juice were successfully identified.