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Singh A, Enjapoori AK, Gibert Y, Dwyer KM. The protective effects of human milk-derived peptides on the pancreatic islet biology. Biol Open 2020; 9:bio049304. [PMID: 32694188 PMCID: PMC7438016 DOI: 10.1242/bio.049304] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Accepted: 07/09/2020] [Indexed: 12/15/2022] Open
Abstract
Several epidemiological studies support the protective role of breastfeeding in reducing the risk for type 1 diabetes. Human breast milk is the perfect nutrition for infants and contains many complex proteins, lipids and carbohydrates. In this study, we examined the physiological effects of human milk-derived opioid peptides, β-casomorphins (BCM), and compared them with bovine-milk-derived opioid peptides on pancreatic hormone regulation and β-cell regeneration. Exposure of wild-type zebrafish embryos to 50 µg/ml of human BCM-5 and -7 from 3 days post fertilisation until 6 days post fertilisation resulted in an increased insulin domain of expression while exposure to bovine BCM-5 and -7 significantly reduced the insulin domain of expression as analysed by whole-mount in situ hybridisation. These changes may be accounted for by reduced insulin expression or β-cell number and were mitigated by the µ-opioid receptor antagonist, naloxone. The effect of BCM on β-cell regeneration was assessed following ablation of β-cells in Tg (ins: CFP-NTR) zebrafish from 3 days post fertilisation to 4 days post fertilisation, followed by exposure of bovine and human BCM-5 and -7 (50 µg/ml) from 4 days post fertilisation until 7 days post fertilisation. The regenerative capacity of β-cells was not impeded following exposure to human BCM-5 and -7, whereas the capacity of β-cells to regenerate following bovine BCM-5 and -7 exposure was reduced. Our data suggest that human BCM-5 and -7 may promote β-cell development and enable the regeneration of β-cells, while the bovine-milk-derived peptides, BCM-5 and -7, play an opposite role. These data may provide some biological explanation for the protective effect of breastfeeding on the development of type 1 diabetes.
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Affiliation(s)
- Amitoj Singh
- School of Medicine, Faculty of Health, Deakin University, 75 Pigdons Road, Waurn Ponds, Geelong, VIC 3216, Australia
| | - Ashwantha Kumar Enjapoori
- School of Medicine, Faculty of Health, Deakin University, 75 Pigdons Road, Waurn Ponds, Geelong, VIC 3216, Australia
| | - Yann Gibert
- School of Medicine, Faculty of Health, Deakin University, 75 Pigdons Road, Waurn Ponds, Geelong, VIC 3216, Australia
| | - Karen M Dwyer
- School of Medicine, Faculty of Health, Deakin University, 75 Pigdons Road, Waurn Ponds, Geelong, VIC 3216, Australia
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Enjapoori AK, Kukuljan S, Dwyer KM, Sharp JA. In vivo endogenous proteolysis yielding beta-casein derived bioactive beta-casomorphin peptides in human breast milk for infant nutrition. Nutrition 2019; 57:259-267. [DOI: 10.1016/j.nut.2018.05.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Revised: 05/15/2018] [Accepted: 05/29/2018] [Indexed: 10/28/2022]
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Newman J, Sharp JA, Enjapoori AK, Bentley J, Nicholas KR, Adams TE, Peat TS. Structural characterization of a novel monotreme-specific protein with antimicrobial activity from the milk of the platypus. Acta Crystallogr F Struct Biol Commun 2018; 74:39-45. [PMID: 29372906 PMCID: PMC5947691 DOI: 10.1107/s2053230x17017708] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Accepted: 12/12/2017] [Indexed: 11/10/2022] Open
Abstract
Monotreme lactation protein (MLP) is a recently identified protein with antimicrobial activity. It is present in the milk of monotremes and is unique to this lineage. To characterize MLP and to gain insight into the potential role of this protein in the evolution of lactation, the crystal structure of duck-billed platypus (Ornithorhynchus anatinus) MLP was determined at 1.82 Å resolution. This is the first structure to be reported for this novel, mammalian antibacterial protein. MLP was expressed as a FLAG epitope-tagged protein in mammalian cells and crystallized readily, with at least three space groups being observed (P1, C2 and P21). A 1.82 Å resolution native data set was collected from a crystal in space group P1, with unit-cell parameters a = 51.2, b = 59.7, c = 63.1 Å, α = 80.15, β = 82.98, γ = 89.27°. The structure was solved by SAD phasing using a protein crystal derivatized with mercury in space group C2, with unit-cell parameters a = 92.7, b = 73.2, c = 56.5 Å, β = 90.28°. MLP comprises a monomer of 12 helices and two short β-strands, with much of the N-terminus composed of loop regions. The crystal structure of MLP reveals no three-dimensional similarity to any known structures and reveals a heretofore unseen fold, supporting the idea that monotremes may be a rich source for the identification of novel proteins. It is hypothesized that MLP in monotreme milk has evolved to specifically support the unusual lactation strategy of this lineage and may have played a central role in the evolution of these mammals.
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Affiliation(s)
- Janet Newman
- Biomedical Manufacturing, CSIRO, 343 Royal Parade, Parkville, VIC 3052, Australia
| | - Julie A. Sharp
- Institute for Frontier Materials, Deakin University, Geelong, VIC 3217, Australia
| | | | - John Bentley
- Biomedical Manufacturing, CSIRO, 343 Royal Parade, Parkville, VIC 3052, Australia
| | - Kevin R. Nicholas
- Institute for Frontier Materials, Deakin University, Geelong, VIC 3217, Australia
| | - Timothy E. Adams
- Biomedical Manufacturing, CSIRO, 343 Royal Parade, Parkville, VIC 3052, Australia
| | - Thomas S. Peat
- Biomedical Manufacturing, CSIRO, 343 Royal Parade, Parkville, VIC 3052, Australia
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Enjapoori AK, Lefèvre CM, Nicholas KR, Sharp JA. Hormonal regulation of platypus Beta-lactoglobulin and monotreme lactation protein genes. Gen Comp Endocrinol 2017; 242:38-48. [PMID: 26673872 DOI: 10.1016/j.ygcen.2015.12.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2015] [Revised: 11/27/2015] [Accepted: 12/04/2015] [Indexed: 12/16/2022]
Abstract
Endocrine regulation of milk protein gene expression in marsupials and eutherians is well studied. However, the evolution of this complex regulation that began with monotremes is unknown. Monotremes represent the oldest lineage of extant mammals and the endocrine regulation of lactation in these mammals has not been investigated. Here we characterised the proximal promoter and hormonal regulation of two platypus milk protein genes, Beta-lactoglobulin (BLG), a whey protein and monotreme lactation protein (MLP), a monotreme specific milk protein, using in vitro reporter assays and a bovine mammary epithelial cell line (BME-UV1). Insulin and dexamethasone alone provided partial induction of MLP, while the combination of insulin, dexamethasone and prolactin was required for maximal induction. Partial induction of BLG was achieved by insulin, dexamethasone and prolactin alone, with maximal induction using all three hormones. Platypus MLP and BLG core promoter regions comprised transcription factor binding sites (e.g. STAT5, NF-1 and C/EBPα) that were conserved in marsupial and eutherian lineages that regulate caseins and whey protein gene expression. Our analysis suggests that insulin, dexamethasone and/or prolactin alone can regulate the platypus MLP and BLG gene expression, unlike those of therian lineage. The induction of platypus milk protein genes by lactogenic hormones suggests they originated before the divergence of marsupial and eutherians.
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Affiliation(s)
- Ashwantha Kumar Enjapoori
- School of Medicine, Deakin University, 75 Pigdons Road, Waurn Ponds, Geelong, Victoria 3216, Australia.
| | - Christophe M Lefèvre
- School of Medicine, Deakin University, 75 Pigdons Road, Waurn Ponds, Geelong, Victoria 3216, Australia.
| | - Kevin R Nicholas
- School of Medicine, Deakin University, 75 Pigdons Road, Waurn Ponds, Geelong, Victoria 3216, Australia; Department of Anatomy and Cell Biology, Monash University, Clayton, Victoria 3800, Australia.
| | - Julie A Sharp
- School of Medicine, Deakin University, 75 Pigdons Road, Waurn Ponds, Geelong, Victoria 3216, Australia; Department of Anatomy and Cell Biology, Monash University, Clayton, Victoria 3800, Australia; Institute for Frontier Materials, Deakin University, 75 Pigdons Road, Waurn Ponds, Geelong, Victoria 3216, Australia.
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Enjapoori AK, Grant TR, Nicol SC, Lefèvre CM, Nicholas KR, Sharp JA. Monotreme lactation protein is highly expressed in monotreme milk and provides antimicrobial protection. Genome Biol Evol 2014; 6:2754-73. [PMID: 25245409 PMCID: PMC4224336 DOI: 10.1093/gbe/evu209] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Monotremes (platypus and echidna) are the descendants of the oldest ancestor of all extant mammals distinguished from other mammals by mode of reproduction. Monotremes lay eggs following a short gestation period and after an even briefer incubation period, altricial hatchlings are nourished over a long lactation period with milk secreted by nipple-less mammary patches located on the female’s abdomen. Milk is the sole source of nutrition and immune protection for the developing young until weaning. Using transcriptome and mass spectrometry analysis of milk cells and milk proteins, respectively, a novel Monotreme Lactation Protein (MLP) was identified as a major secreted protein in milk. We show that platypus and short-beaked echidna MLP genes show significant homology and are unique to monotremes. The MLP transcript was shown to be expressed in a variety of tissues; however, highest expression was observed in milk cells and was expressed constitutively from early to late lactation. Analysis of recombinant MLP showed that it is an N-linked glycosylated protein and biophysical studies predicted that MLP is an amphipathic, α-helical protein, a typical feature of antimicrobial proteins. Functional analysis revealed MLP antibacterial activity against both opportunistic pathogenic Staphylococcus aureus and commensal Enterococcus faecalis bacteria but showed no effect on Escherichia coli, Pseudomonas aeruginosa, Staphylococcus epidermidis, and Salmonella enterica. Our data suggest that MLP is an evolutionarily ancient component of milk-mediated innate immunity absent in other mammals. We propose that MLP evolved specifically in the monotreme lineage supporting the evolution of lactation in these species to provide bacterial protection, at a time when mammals lacked nipples.
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Affiliation(s)
| | - Tom R Grant
- School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Stewart C Nicol
- School of Biological Sciences, University of Tasmania, Hobart, Tasmania, Australia
| | | | - Kevin R Nicholas
- School of Medicine, Deakin University, Geelong, Victoria, Australia Department of Anatomy and Developmental Biology, Monash University, Clayton, Victoria, Australia
| | - Julie A Sharp
- School of Medicine, Deakin University, Geelong, Victoria, Australia Institute for Frontier Materials, Deakin University, Geelong, Victoria, Australia
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