Untargeted Metabolomic Analysis of Gestationally Matched Human and Bovine Milk Samples at 2-Weeks Postnatal

Objectives

Human breast milk is the ideal nutrition source for infant development during the first year of life. Epidemiological data demonstrates that bovine whole milk is often substituted for human milk during the first 12-months of life and may be associated with adverse infant outcomes. The goal of this project is to interrogate the human and bovine milk metabolome at 2-weeks postnatal to identify unique and overlapping metabolites that may impact infant health outcomes.

Methods

Human milk (n = 10) was collected at 2-weeks postpartum from normal weight mothers (pre-pregnant BMI <25 kg/m2) that vaginally delivered term infants and planned to exclusively breastfeed for at least 2-months. Similarly, bovine milk (n = 10) was collected 2-weeks postpartum from normal weight primiparous Holstein dairy cows. Dairy cattle were housed in sand-bedded, shaded barns with access to fans and water soakers and fed a common transition cow total mixed ration. Untargeted metabolomics was completed on all milk samples using high-resolution mass spectrometry. Metabolomic analysis was implemented using an open-source containerized metabolomics pipeline. Data processing was completed using MZmine, mummichog and Python were used for statistical analysis.

Results

We detected 716 metabolomic features in human and bovine milk samples after quality control. Our analysis also revealed that 43% (312) of metabolomics features were present in both human and bovine milk, 23% (167) of metabolomics features were unique to human milk and 33% (237) of metabolomics features existed only in bovine milk samples. Pathway analysis revealed that sialic acid and glycosphingolipid metabolism (P < 0.0009) were common to human and bovine milk samples. We also found that amino acid (tryptophan, tyrosine, purine) metabolism (P < 0.005) was unique to bovine samples and vitamin B3 pathways (P = 0.03) was unique to human samples.

Conclusions

Our analysis revealed a core milk metabolome shared between human and bovine samples. Collectively, these results highlight untargeted metabolomics as a potential strategy to identify unique and overlapping metabolites in bovine and human milk that may impact infant health outcomes.

Funding Sources

Research was supported by NIDDK/K01; SECIM P&F; CTSI Pilot Award; Robin Hood Foundation; NIH Loan Repayment Program.

Recruitment and Retention of Pregnant and Breastfeeding Mothers for Longitudinal Clinical Microbiome Studies (OR30-08-19)

Objectives

Accumulating data suggest the health benefits of breastfeeding are, in part, mediated through interactions with the human microbiome. Despite these observations, recruitment of pregnant mothers in longitudinal clinical microbiome studies remains a significant challenge. The goal of this study is to develop data-driven strategies for recruitment and retention of breastfeeding mothers’ into longitudinal clinical microbiome studies.

Methods

We recruited a total of 40 mothers (20 pregnant and 20 breastfeeding) to complete in-depth semi-structured interviews at the UF Clinical and Translational Science Institute. Additionally, mothers were asked to use self-administered microbiome collection kits and complete questionnaires related to health history, infant feeding practices, and physical activity. Informative interviews were designed to identify women's understanding, motivations and barriers surrounding longitudinal clinical research participation and their preferences for providing non-invasive biological samples.

Results

Our preliminary analysis indicates that 1) barriersfor participating in research include convenience, confidentiality and child protection; 2) factors motivating participation in research include general interest in breastfeeding, schedule, and perceived research relevance; 3) participant recruitment should consider social media and 4) biological sample collection should include adequate instructions and drop-off convenience.

Conclusions

The results of this study provide valuable theoretical and practical insights on how to effectively recruit and retain pregnant and breastfeeding women into longitudinal microbiome studies.

Funding Sources

1K01DK115632-01A1.

Intrinsic disorder and multiple phosphorylations constrain the evolution of the flightin N-terminal region

Flightin is a myosin binding phosphoprotein that originated in the ancestor to Pancrustacea ~500 MYA. In Drosophila melanogaster, flightin is essential for length determination and flexural rigidity of thick filaments. Here, we show that among 12 Drosophila species, the N-terminal region is characterized by low sequence conservation, low pI, a cluster of phosphorylation sites, and a high propensity to intrinsic disorder (ID) that is augmented by phosphorylation. Using mass spectrometry, we identified eight phosphorylation sites within a 29 amino acid segment in the N-terminal region of D. melanogaster flightin. We show that phosphorylation of D. melanogaster flightin is modulated during flight and, through a comparative analysis to orthologs from other Drosophila species, we found phosphorylation sites that remain invariant, sites that retain the charge character, and sites that are clade-specific. While the number of predicted phosphorylation sites differs across species, we uncovered a conserved pattern that relates the number of phosphorylation sites to pI and ID. Extending the analysis to orthologs of other insects, we found additional conserved features in flightin despite the near absence of sequence identity. Collectively, our results demonstrate that structural constraints demarcate the evolution of the highly variable N-terminal region.