A complete proteomic profile of human and bovine milk exosomes by liquid chromatography mass spectrometry

ABSTRACT

Background

The present study investigates the proteomic content of milk-derived exosomes. A detailed description of the content of milk exosomes is essential to improve our understanding of the various components of milk and their role in nutrition.

Methods

The exosomes used in this study were isolated as previously described and characterized by their morphology, particle concentration, and the presence of exosomal markers. Human and bovine milk exosomes were evaluated using Information-Dependent Acquisition (IDA) Mass Spectrometry. A direct comparison is made between their proteomic profiles.

Results

IDA analyses revealed similarities and differences in protein content. About 229 and 239 proteins were identified in the human and bovine milk exosome proteome, respectively, of which 176 and 186 were unique to each species. Fifty-three proteins were common in both groups. These included proteins associated with specific biological processes and molecular functions. Most notably, the 4 abundant milk proteins lactadherin, butyrophilin, perilipin-2, and xanthine dehydrogenase/oxidase were present in the top 20 list for both human and bovine milk exosomes.

Conclusion

The milk exosome protein profiles we have provided are crucial new information for the field of infant nutrition. They provide new insight into the components of milk from both humans and bovines.

KEYWORDS:

• Exosomes
• bovine
• milk
• proteomic
• mass spectrometry

Disclosure statement

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties. The authors declare that they have no conflicts of interest.

Author contribution

K. Vaswani, H. Peiris, and Y. Q. Koh conducted the experiments. K. Vaswani and H. Peiris collected the bovine milk samples. R.J. Hill, T. Harb, and P.S.W. Davies collected the human milk samples. T. Harb and H. Peiris categorized and stored the milk samples. J. Logan, H. Peiris, and M.D. Mitchell reviewed the article and contributed to the project design. K. Vaswani and Y. Q. Koh performed the characterization and proteomic experiments. B. J. Arachchige and S. Reed conducted mass spec analysis.

Reviewer disclosures

Peer reviewers in this manuscript have no relevant financial or other relationships to disclose.

Supplemental data

Supplemental data for this article can be accessed here.

Correction Statement

This article has been republished with minor changes. These changes do not impact the academic content of the article.

Additional information

Funding

This work was supported by a partnership between the New Zealand Ministry for Business, Innovation and Employment, and New Zealand dairy farmers through DairyNZ. (DRCX1302) and in part by the Australian Research Council Discovery Grant (DP 140103009), Mead Johnson Nutrition, as well as the QUT Children's and Adolescent Seed Fund (CAH).