Project description:Over the course of milk digestion, native milk proteases and infant digestive proteases fragment intact proteins into peptides with potential bioactivity. This study investigated the release of peptides over three hours of gastric digestion in 14 preterm infant sample sets. The peptide content was extracted and analyzed from milk and gastric samples via Orbitrap tandem mass spectrometry. The relative ion intensity (abundance) and count of peptides in each sample were compared over time and between infants fed milk fortified with bovine milk fortifier and infants fed unfortified milk. Bioactivity of the identified peptides was predicted by sequence homology to known bioactive milk peptides. Both total and bioactive peptide abundance and count continuously increased over three hours of gastric digestion. After accounting for infant weight, length, and post-conceptual age, fortification of milk limited the release of peptides from human milk proteins. Peptides that survived further gastric digestion after their initial release were structurally more similar to bioactive peptides than non-surviving peptides. This work is the first to provide a comprehensive profile of milk peptides released during gastric digestion over time, which is an essential step in determining which peptides are most likely to be biologically relevant in the infant.
Project description:Proteomic profiles of cell free supernatants from preterm infant bacterial isolates following growth on human milk bioactive components
Project description:Preterm infants born <32 weeks gestation have abnormal microbial colonisation and dysregulated inflammation within the gut. Preterm infant-derived intestinal organoids (PIOs) represent a valuable model for investigating gut microbiome-host interactions and inflammatory responses. We optimised an inflammation model in PIO monolayers incubated within an anaerobic co-culture system that recreates the physiological oxygen gradient of the intestinal epithelium. We trialled multiple stimuli, including live and heat-killed pathobiont consortia, lipopolysaccharide (LPS) and flagellin. We found that a combination of apical LPS and basolateral flagellin, incubated for 3 hours, elicited the most robust response. This was characterised by enhanced pro-inflammatory cytokine secretion, the potential for chemokine-driven immune recruitment, TNFα and IL17C pathway signalling, shifts from NF-κB to AP-1-mediated responses, and signs of tissue remodelling. This provides a framework for appropriate study design to disentangle the impacts of microbiome-host interactions in health and disease using intestinal organoids.
Project description:Preterm infants born <32 weeks gestation have abnormal microbial colonisation and dysregulated inflammation within the gut. Preterm infant-derived intestinal organoids (PIOs) represent a valuable model for investigating gut microbiome-host interactions and inflammatory responses. We optimised an inflammation model in PIO monolayers incubated within an anaerobic co-culture system that recreates the physiological oxygen gradient of the intestinal epithelium. We trialled multiple stimuli, including live and heat-killed pathobiont consortia, lipopolysaccharide (LPS) and flagellin. We found that a combination of apical LPS and basolateral flagellin, incubated for 3 hours, elicited the most robust response. This was characterised by enhanced pro-inflammatory cytokine secretion, the potential for chemokine-driven immune recruitment, TNFα and IL17C pathway signalling, shifts from NF-κB to AP-1-mediated responses, and signs of tissue remodelling. This provides a framework for appropriate study design to disentangle the impacts of microbiome-host interactions in health and disease using intestinal organoids.
Project description:Human breast milk as part of late preterm infant study. Samples were extracted with ethanol and processed on a Bruker Daltonics maXis Impact and C18 RP-UPLC for untargeted metabolomic analysis. Positive polarity acquisition of LC-MS/MS.
Project description:91 preterm infant gut metaproteomes measured in technical duplicate using an eleven salt pulse 2D-LC-MS/MS method. Samples represent 17 preterm infants over the first several weeks of life, of which 6 preterm infants eventually developed necrotizing enterocolitis.
Project description:Hundreds of naturally occurring milk peptides have been found in term human milk. Whether there are differences between the levels of these peptides between term and preterm milk remains unknown. Premature milk is produced before complete maturation of the mammary gland and is under the influence of a different hormonal milieu, which could change enzymatic activity and protein expression within the mammary gland and result in an altered peptide profile. We employed nano-liquid chromatography tandem mass spectrometry to identify naturally occurring peptides in term and premature milks at multiple time-points across lactation and compare the abundances of these peptides. We found that preterm milks produced more unique peptide sequences than term milks on average (359 vs. 286). The peptides identified were searched for overlapping sequences with an in-house database of known functional peptides. Specifically, we found that both term and preterm milks contain peptides overlapping with known sequences with antimicrobial, opioid antagonist and immunomodulatory actions. We also compared the enzymes involved in degradation of both milks via bioinformatic analysis. This analysis reveals that plasmin is more active in preterm milk than term milk.
Project description:Human milk, the best enteral selection for a preterm infant, becomes altered during freezing and soluble free fatty acid is generated over time. Free fatty acids may form complexes, such as the oleic acid-bound protein called HAMLET (human α‐lactalbumin made lethal to tumor cells). We determined the in vitro biological activity of preterm human milk protein‐oleic complexes (HAMLET-like complexes) and tested the hypothesis that laboratory-synthesized HAMLET exhibits cytotoxicity in human immature epithelial intestinal cell culture. Thirty-four milk samples from 15 mothers of hospitalized preterm infants were donated over time. Milk fractions were tested repeatedly for FHs 74 Int and HIEC-6 fetal cell cytotoxicity, using a sensitive viability assay. Protein and fatty acid identities were confirmed by Western blot, high performance liquid chromatography, and mass spectrometry. Cytotoxicity of intestinal cells exposed to milk increased respective to milk storage time (p<0.001) and was associated with free oleic acid (p=0.009). Synthesized HAMLET was cytotoxic in cultures of both lines. Preterm milk samples killed most cells in culture after an average 54 days in frozen storage (95% C.I. 34-72 days). After prolonged storage time, preterm milk and HAMLET showed a degree of cytotoxicity to immature intestinal cells in culture. Protein was reduced 221 in 1 mM dithiothreitol and alkylated in 5.5 mM
Project description:Injury occurring during critical periods of development may have long-term effects on inflammatory responses. Periventricular leukomalacia (PVL) is the most common cause of cerebral palsy (CP) in preterm infant. Activated leukocytes are the main source of inflammatory cytokines that give rise to white matter damage and CP in preterm infant. Here, we tested the hypothesis that inflammation profiles as pathogenic mediators for the occurrence of PVL in the neonatal period may persist in preterm children with CP at school age. Five preterm children with PVL-induced CP and gestational age-matched five preterm children with normal neurodevelopment were recruited from follow up clinics. Proinflammatory gene expression in the PBMCs from preterm children were determined by Superarray PCR study.
Project description:Milk and milk products such as infant formula (IF) play a fundamental role in serving the nutritional needs of the developing infant. Extracellular vesicles (EVs) in human (HM) and cow’s milk (CM) contain molecular cargo such as proteins and micro(mi)RNA that serve as functional messengers between cells and may be of importance to infant health. Here, we have developed a pipeline using advanced proteomics and transcriptomics to enable cross-species comparison of milk and IF EVs. EVs from HM, CM and IF were subjected to data-independent acquisition mass spectrometry and RNA-seq. Differentially abundant proteins (143) and miRNAs (514) (false discovery rate < 0.01) were identified in HM and CM EVs, and CM EV proteins and miRNAs were conserved in IF EVs (~20-90%). We foresee this work to be used in large scale studies to determine biologically relevant species-specific differences in milk EVs that could be leveraged to improve IF products.