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1.
ACS Appl Mater Interfaces ; 15(28): 34031-34043, 2023 Jul 19.
Article in English | MEDLINE | ID: mdl-37399520

ABSTRACT

Cotton fabrics with superhydrophobic, antibacterial, UV protection, and photothermal properties were developed using Ag/PDMS coatings, and the role of coating formulations on the obtained functionalities was studied. Specific attention was paid to understanding the relationships between the fabrics' superhydrophobicity and antibacterial activity against Escherichia coli (E. coli) bacteria. UV protection performance of Ag/PDMS coatings was thoroughly evaluated based on the variation of UV transmission rate through coated fabrics and photoinduced chemiluminescence spectra. Moreover, the effect of silver nanoparticles (Ag NPs) and PDMS on developing a photothermal effect on fabrics was discussed. It was found that the content of Ag NPs and PDMS played critical roles in determining the water contact angle (WCA) on modified fabrics. The largest WCA was 171.31°, which was durable even after numerous accelerated wash cycles and abrasions. Antibacterial activity of fabrics showed the positive effect of pure PDMS in bacterial growth inhibition. Moreover, it was found that the antibacterial performance was greatly affected by the content of Ag NPs loaded on fabrics rather than their superhydrophobic status. Moreover, increasing the content of Ag NPs boosted the UV protection level of fabrics, improved fabrics photostability, and reduced the UV transmission rate through fabrics. Testing the photothermal effect confirmed that the content of Ag NPs and PDMS both played prominent roles, where Ag acted as a photothermal agent and PDMS determined the NIR reflection rate from the coated surface. The modified fabrics were characterized using TGA, SEM, FTIR, and XRD techniques, and it was confirmed that using a higher amount of PDMS increased the amount of Ag NPs deposition on fabrics.


Subject(s)
Metal Nanoparticles , Metal Nanoparticles/chemistry , Escherichia coli , Silver/pharmacology , Silver/chemistry , Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/chemistry , Hydrophobic and Hydrophilic Interactions
2.
ACS Biomater Sci Eng ; 7(12): 5555-5572, 2021 12 13.
Article in English | MEDLINE | ID: mdl-34719916

ABSTRACT

A series of quaternary Zn-Al-Cu-Li alloys with different weight fractions of Cu, Al, and Li were developed and investigated for potential application in high load bearing bioresorbable implants. The developed alloys provided various fractions of binary and ternary intermetallic structures, which resulted in formation of multiphase microstructures containing a zinc-rich η-phase and LiZn4 and CuZn4 phases. The intermetallic phases promoted grain refinement and a good combination of mechanical properties. The developed Zn-2Al-4Cu-0.6Li alloy showed strength and ductility close to commercially pure Ti alloys with a UTS value of ∼535 MPa and elongation of 37%. The examination of in vitro corrosion behavior of the developed alloys in the modified Hanks' solution revealed suitable corrosion rates (∼38.5 µm/year). The moderate corrosion rate was controlled by the formation of a homogeneous layer of stable corrosion products that protected the alloys from the corrosive environment, particularly in the late stages of immersion. The developed alloys with the most promising mechanical and corrosion properties appeared to be biocompatible to mouse fibroblast cells and human umbilical mesenchymal stem cells, making them suitable candidates for implant applications.


Subject(s)
Alloys , Zinc , Animals , Corrosion , Materials Testing , Mice , Tensile Strength
3.
Mater Sci Eng C Mater Biol Appl ; 122: 111897, 2021 Mar.
Article in English | MEDLINE | ID: mdl-33641900

ABSTRACT

A series of Zn-Al-Li alloys with potential application in bioresorbable implants were cast, thermomechanically processed and tested. The formation of secondary phases, such as LiZn4, LiZn3Al and Al3Li, contributed to both dynamic recrystallization and grain refinement of the matrix (η-phase) during the hot-extrusion process, leading to grain sizes as small as 1.75 µm for Zn-4Al-0.6Li alloy (wt%). This alloy exhibited an ultimate tensile strength (UTS) of 451 MPa, a total elongation of 46% and a corrosion rate of 60 µm/year in simulated body fluid. The grain refinement played a major role in increasing the strength, but it also weakened the basal texture and promoted non-basal slip and grain boundary sliding, thus contributing to the increased plastic deformation of the alloy. The corrosion rate was affected by a layer of zinc oxide and phosphate formed in the early stages of the immersion tests. The corrosion products protected the substrate and tended to reduce the corrosion rate over time. The developed Zn-4Al-0.6Li and Zn-6Al-0.4Li alloys which showed promising mechanical and corrosion properties appeared to be cytocompatible in the mouse fibroblast cell line and human umbilical mesenchymal stem cells making them promising candidates for bioresorbable stent and implant applications.


Subject(s)
Absorbable Implants , Alloys , Animals , Corrosion , Materials Testing , Mice , Tensile Strength , Zinc
4.
Cell Tissue Res ; 384(2): 333-352, 2021 May.
Article in English | MEDLINE | ID: mdl-33439347

ABSTRACT

Assessing the role of lactogenic hormones in human mammary gland development is limited due to issues accessing tissue samples and so development of a human in vitro three-dimensional mammosphere model with functions similar to secretory alveoli in the mammary gland can aid to overcome this shortfall. In this study, a mammosphere model has been characterised using human mammary epithelial cells grown on either mouse extracellular matrix or agarose and showed insulin is essential for formation of mammospheres. Insulin was shown to up-regulate extracellular matrix genes. Microarray analysis of these mammospheres revealed an up-regulation of differentiation, cell-cell junctions, and cytoskeleton organisation functions, suggesting mammosphere formation may be regulated through ILK signalling. Comparison of insulin and IGF-1 effects on mammosphere signalling showed that although IGF-1 could induce spherical structures, the cells did not polarise correctly as shown by the absence of up-regulation of polarisation genes and did not induce the expression of milk protein genes. This study demonstrated a major role for insulin in mammary acinar development for secretory differentiation and function indicating the potential for reduced lactational efficiency in women with obesity and gestational diabetes.


Subject(s)
Insulin/metabolism , Mammary Glands, Animal/physiopathology , Animals , Cell Culture Techniques , Cell Differentiation , Female , Humans , Mice
5.
Respirology ; 25(12): 1243-1249, 2020 12.
Article in English | MEDLINE | ID: mdl-32365431

ABSTRACT

BACKGROUND AND OBJECTIVE: BT and interleukin-blocking monoclonal antibodies are both effective therapies for severe asthma, but there have been no direct comparisons between the two treatments. The aim of this study was to compare the efficacy and safety of BT and mepolizumab, in a real-world setting. METHODS: Patients with severe asthma despite optimized inhaler therapy were drawn from a severe asthma clinic in a tertiary hospital. Every patient commencing therapy with BT or mepolizumab was prospectively included in a national registry. At predetermined assessment points over a 12-month period, assessments were made of ACQ, spirometry, oral corticosteroid requiring exacerbations, reliever medication and maintenance oral corticosteroid use. RESULTS: A total of 91 patients with severe asthma participated: mean ACQ score 3.5 ± 1.0, FEV1 51.4 ± 17.7%, maintenance oral steroids 48.3% and 11.5 ± 10.0 inhalations/day reliever therapy. Forty-seven patients received mepolizumab and 44 received BT. Baseline characteristics were similar except significantly higher blood eosinophil count in the mepolizumab group. At 12 months, there were no differences between treatment outcomes for ACQ (1.9 ± 1.3 mepolizumab vs 1.7 ± 1.3 BT), exacerbation rate (0.9 ± 1.1 vs 0.9 ± 1.5), reduction in reliever use (-6.3 ± 10.5 vs -5.0 ± 8.8 puffs/day) or reduction in oral corticosteroids (-3.3 ± 7.5 vs - 5.8 ± 6.7 mg/day). The FEV1 improved equally (160 ± 290 vs 150 ± 460 mL). Readmission or prolonged admission was observed in 18.2% of BT patients, whilst 25.5% of mepolizumab patients had discontinued treatment at 12 months, 14.9% due to an adverse event or non-compliance. CONCLUSION: The results suggest that BT is as efficacious as mepolizumab for the treatment of severe asthma.


Subject(s)
Antibodies, Monoclonal, Humanized , Asthma , Bronchial Thermoplasty , Adrenal Cortex Hormones/therapeutic use , Anti-Asthmatic Agents/administration & dosage , Anti-Asthmatic Agents/adverse effects , Antibodies, Monoclonal, Humanized/administration & dosage , Antibodies, Monoclonal, Humanized/adverse effects , Asthma/epidemiology , Asthma/immunology , Asthma/physiopathology , Asthma/therapy , Australia/epidemiology , Bronchial Thermoplasty/adverse effects , Bronchial Thermoplasty/methods , Female , Humans , Interleukin-5/antagonists & inhibitors , Male , Middle Aged , Registries/statistics & numerical data , Severity of Illness Index , Spirometry/methods , Treatment Outcome
6.
ACS Biomater Sci Eng ; 6(9): 5305-5314, 2020 09 14.
Article in English | MEDLINE | ID: mdl-33455279

ABSTRACT

Natural melanin is recognized as a biocompatible photothermal agent because of its biologically derived nature and efficient photothermal conversion ability. Here, yak hair melanin (YM) is added to polyurethane (PU) for the fabrication of NIR-photoresponsive shape memory implants. The in vitro toxicity of the YM/PU composites is carried out by exposing them to human mesenchymal stem cells (hMSCs) and mouse fibroblast (L929) cells lines for 24 h, while the in vivo toxicity is investigated by implanting the YM/PU composites in the mouse for two months. No significant differences on cell viability, blood chemistry, hematology, and histological results are observed between YM/PU composites and control groups, suggesting their excellent biocompatibility. The biostability of the YM/PU composites is confirmed by monitoring their in vitro degradation for 12 weeks. The YM/PU column implanted in the back subcutis or vagina of the mouse rapidly recovered to its original state within 60 s under a very low NIR laser (808 nm, 0.5 W/cm2) intensity, which is much lower than the general laser intensity for photothermal cancer therapy (1-2 W/cm2). This work confirms the applicability of the YM/PU composites as long-term implant materials and expedites the use of YM/PU composites as cost-effective candidates for biomedical applications.


Subject(s)
Melanins , Polyurethanes , Animals , Cell Survival , Mice , Prostheses and Implants
7.
Transgenic Res ; 28(5-6): 573-587, 2019 12.
Article in English | MEDLINE | ID: mdl-31599375

ABSTRACT

EchAMP, the tenth most abundant transcript expressed in the mammary gland of echidna, has in vitro broad-spectrum antibacterial effects. However, the effects of EchAMP on mastitis, a condition where inflammation is triggered following mammary gland infection, has not been investigated. To investigate the impact of EchAMP against mastitis, EchAMP transgenic mice were generated. In antibacterial assays, the whey fractions of milk from transgenic mice significantly reduced growth of Staphylococcus aureus, Bacillus subtilis, Escherichia coli and Pseudomonas aeruginosa compared with whey fractions from wildtype mice. Furthermore, a mastitis model created by infecting mammary gland with these four bacterial strains displayed a significant reduction in bacterial load in transgenic mice injected with S. aureus and B. subtilis. On further confirmation, histomorphologic analysis showed absence of necrosis and cell infiltration in the mammary glands of transgenic mice. To understand the role of EchAMP against inflammation, we employed an LPS-injected mastitis mouse model. LPS is known to induce phopshorylation of NF-κB and MAPK pathways, which in turn activate downstream proinflammatory signaling mediators, to promote inflammation. In LPS-treated EchAMP transgenic mice, phosphorylation levels of NF-κB, p38 and ERK1/2 were significantly downregulated. Furthermore, in mammary gland of transgenic mice, there was a significant downregulation of mRNA levels of proinflammatory cytokines, namely TNF-α, IL-6 and IL-1ß. Taken together, these data suggest that EchAMP has an antiinflammatory response and is effective against S. aureus and B. subtilis. We suggest that EchAMP may be a potential prophylactic protein against mastitis in dairy animals by expressing this gene in their mammary gland.


Subject(s)
Antimicrobial Cationic Peptides/genetics , Inflammation/genetics , Mastitis/genetics , Staphylococcal Infections/genetics , Animals , Female , Humans , Inflammation/chemically induced , Inflammation/microbiology , Inflammation/prevention & control , Interleukin-1beta/genetics , Interleukin-6/genetics , Lipopolysaccharides/toxicity , MAP Kinase Signaling System/genetics , Mammary Glands, Animal/metabolism , Mastitis/chemically induced , Mastitis/microbiology , Mastitis/prevention & control , Mice , Mice, Transgenic/genetics , NF-kappa B/genetics , Staphylococcal Infections/microbiology , Staphylococcal Infections/prevention & control , Staphylococcus aureus/genetics , Staphylococcus aureus/pathogenicity , Tachyglossidae/genetics , Tumor Necrosis Factor-alpha/genetics
8.
Biochim Biophys Acta Biomembr ; 1861(6): 1260-1274, 2019 06 01.
Article in English | MEDLINE | ID: mdl-30951703

ABSTRACT

BACKGROUND: Antibiotic resistance is a problem that necessitates the identification of new antimicrobial molecules. Milk is known to have molecules with antimicrobial properties (AMPs). Echidna Antimicrobial Protein (EchAMP) is one such lactation specific AMP exclusively found in the milk of Echidna, an egg-laying mammal geographically restricted to Australia and New Guinea. Previous studies established that EchAMP exhibits substantial bacteriostatic activity against multiple bacterial genera. However, the subsequent structural and functional studies were hindered due to the unavailability of pure protein. RESULTS: In this study, we expressed EchAMP protein using a heterologous expression system and successfully purified it to >95% homogeneity. The purified recombinant protein exhibits bacteriolytic activity against both Gram-positive and Gram-negative bacteria as confirmed by live-dead staining and scanning electron microscopy. Structurally, this AMP belongs to the family of intrinsically disordered proteins (IDPs) as deciphered by the circular-dichroism, tryptophan fluorescence, and NMR spectroscopy. Nonetheless, EchAMP has the propensity to acquire structure with amphipathic molecules, or membrane mimics like SDS, lipopolysaccharides, and liposomes as again observed through multiple spectroscopic techniques. CONCLUSIONS: Recombinant EchAMP exhibits broad-spectrum bacteriolytic activity by compromising the bacterial cell membrane integrity. Hence, we propose that this intrinsically disordered antimicrobial protein interact with the bacterial cell membrane and undergoes conformational changes to form channels in the membrane resulting in cell lysis. GENERAL SIGNIFICANCE: EchAMP, the evolutionarily conserved, lactation specific AMP from an oviparous mammal may find application as a broad-spectrum antimicrobial against pathogens that affect mammary gland or otherwise cause routine infections in humans and livestock.


Subject(s)
Anti-Bacterial Agents/pharmacology , Milk/chemistry , Peptides/pharmacology , Tachyglossidae , Animals , Anti-Bacterial Agents/chemistry , Gram-Negative Bacteria/drug effects , Gram-Positive Bacteria/drug effects , Microbial Sensitivity Tests , Peptides/chemistry , Protein Conformation , Protein Conformation, alpha-Helical
9.
Nestle Nutr Inst Workshop Ser ; 90: 203-215, 2019.
Article in English | MEDLINE | ID: mdl-30865988

ABSTRACT

Significantly preterm and low-birthweight (LBW) babies have diminished lung and gut development, generally fail to thrive, have increased mortality and higher frequency of mature-onset disease. Mothers often cannot breastfeed, and babies receive either formula or pasteurized donor milk, which may further limit the baby's recovery. New approaches are required to manage the early stages of neonatal development. The tammar wallaby, an Australian marsupial, has a short gestation and a simple placenta, and gives birth to an altricial young equivalent to a final trimester human embryo. The neonate remains in the pouch and attached to the teat for 100 days postpartum. The mother slows growth of the young and progressively changes the composition of the milk to deliver signals for organ development, including the lung and gut. This closely resembles the relationship between the human fetus and delivery of placental and uterine bioactives. Datasets comprised of differentially expressed genes coding for secreted proteins in early lactation in the tammar mammary gland have been compared to databases produced from human placenta, amniotic fluid, colostrum and milk to identify human homologues for the putative signaling molecules for organ development. These data will be used to develop milk fortifiers for treatment of preterm and LBW babies in both the developed and the developing world.


Subject(s)
Animals, Newborn/growth & development , Child Development , Macropodidae/growth & development , Animals , Colostrum/chemistry , Female , Humans , Infant, Low Birth Weight/growth & development , Infant, Newborn , Infant, Premature/growth & development , Lactation , Lung/growth & development , Milk , Milk, Human/chemistry , Models, Animal
10.
Nutrition ; 57: 259-267, 2019 01.
Article in English | MEDLINE | ID: mdl-30199719

ABSTRACT

Objective Beta-casein is a major protein in breast milk and an important source for several bioactive peptides that are encrypted within the sequence. Beta-casomorphins (BCMs) are short-chain proteolytic peptides that are derived from the beta-casein protein and have opioid effects in newborns. Human milk is known to contain naturally occurring milk-protein-derived bioactive peptides but the identification of naturally occurring beta-casein-derived BCMs in human breast milk has been limited due to difficulties in the detection of BCM peptides, which are small and circulate in low concentrations. Methods The present study aimed to identify the naturally occurring BCM peptides from beta-casein in human breast milk using liquid chromatography-tandem mass spectrometry. The BCM peptides identified in the breast milk were analysed to predict the milk proteases responsible for the cleavage patterns using a computational tool EnzymePredictor. Results In-depth peptidomics analysis of breast milk samples that were collected at different lactation stages during human lactation revealed the presence of BCMs including BCM-8, -9, -10, and -11 as well as precursors and truncated forms of the original peptide, which suggests that milk protease activity in the mammary gland generates biologically relevant BCMs. Conclusions To our knowledge, this is the first report to describe the presence of naturally occurring human BCM-10 and -11 in breast milk. Our study provides evidence of beta-casein-derived BCM peptides in human milk before infant digestion. Proteases that are present in milk are likely specific in their proteolysis of beta-casein. The identified bioactive BCM-8, -9, -10, and -11 as well as the precursor peptides meet the structural requirements to elicit opioid, immunomodulatory, antioxidative, and satiety functions in newborns.


Subject(s)
Breast Feeding , Endorphins/metabolism , Lactation/metabolism , Milk Proteins/metabolism , Milk, Human/metabolism , Peptide Hydrolases/metabolism , Peptides/metabolism , Adult , Caseins/metabolism , Chromatography, Liquid/methods , Diet , Digestion , Endorphins/pharmacology , Female , Humans , Infant , Infant Nutritional Physiological Phenomena , Infant, Newborn , Proteolysis , Tandem Mass Spectrometry/methods
11.
BMC Genomics ; 19(1): 732, 2018 Oct 05.
Article in English | MEDLINE | ID: mdl-30290757

ABSTRACT

BACKGROUND: After a short gestation, marsupials give birth to immature neonates with lungs that are not fully developed and in early life the neonate partially relies on gas exchange through the skin. Therefore, significant lung development occurs after birth in marsupials in contrast to eutherian mammals such as humans and mice where lung development occurs predominantly in the embryo. To explore the mechanisms of marsupial lung development in comparison to eutherians, morphological and gene expression analysis were conducted in the gray short-tailed opossum (Monodelphis domestica). RESULTS: Postnatal lung development of Monodelphis involves three key stages of development: (i) transition from late canalicular to early saccular stages, (ii) saccular and (iii) alveolar stages, similar to developmental stages overlapping the embryonic and perinatal period in eutherians. Differentially expressed genes were identified and correlated with developmental stages. Functional categories included growth factors, extracellular matrix protein (ECMs), transcriptional factors and signalling pathways related to branching morphogenesis, alveologenesis and vascularisation. Comparison with published data on mice highlighted the conserved importance of extracellular matrix remodelling and signalling pathways such as Wnt, Notch, IGF, TGFß, retinoic acid and angiopoietin. The comparison also revealed changes in the mammalian gene expression program associated with the initiation of alveologenesis and birth, pointing to subtle differences between the non-functional embryonic lung of the eutherian mouse and the partially functional developing lung of the marsupial Monodelphis neonates. The data also highlighted a subset of contractile proteins specifically expressed in Monodelphis during and after alveologenesis. CONCLUSION: The results provide insights into marsupial lung development and support the potential of the marsupial model of postnatal development towards better understanding of the evolution of the mammalian bronchioalveolar lung.


Subject(s)
Gene Expression Profiling , Lung/embryology , Monodelphis/growth & development , Monodelphis/genetics , Organogenesis/genetics , Animals , Lung/physiology , Organ Specificity
12.
Acta Crystallogr F Struct Biol Commun ; 74(Pt 1): 39-45, 2018 Jan 01.
Article in English | MEDLINE | ID: mdl-29372906

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 Šresolution. 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 Šresolution 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, ß = 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, ß = 90.28°. MLP comprises a monomer of 12 helices and two short ß-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.


Subject(s)
Antimicrobial Cationic Peptides/chemistry , Milk Proteins/chemistry , Platypus/metabolism , Amino Acid Sequence , Animals , Anti-Infective Agents/chemistry , Anti-Infective Agents/pharmacology , Antimicrobial Cationic Peptides/genetics , Antimicrobial Cationic Peptides/pharmacology , Crystallization , Crystallography, X-Ray , Enterococcus faecalis/drug effects , Evolution, Molecular , Female , Milk/chemistry , Milk Proteins/genetics , Milk Proteins/pharmacology , Models, Molecular , Phylogeny , Platypus/genetics , Protein Conformation , Protein Structure, Secondary , Recombinant Proteins/chemistry , Recombinant Proteins/genetics , Recombinant Proteins/pharmacology , Staphylococcus aureus/drug effects
13.
Asian Pac J Cancer Prev ; 19(1): 57-63, 2018 Jan 27.
Article in English | MEDLINE | ID: mdl-29373893

ABSTRACT

Extracellular matrix (ECM) plays an important role in the normal physiology of tissues and progression to disease. Earlier studies and our external microarray data analysis indicated that mammary matrix from involuting tissue showed upregulation of genes involved in ECM remodeling. The present study examines the fate of mammary and oral cancer cells grown in the ECM from lactating mammary gland. Our findings show that non-tumorigenic cells, MCF10A and DOK cells did not proliferate but the tumorigenic and metastatic cells, SCC25 and MDA-MB-231, underwent apoptosis when grown on mammary ECM isolated from lactating mice. In addition, the cytokinesis marker, CEP55, was repressed in the oral and breast cancer cells. In contrast, these cells proliferated normally on mammary ECM isolated from mice undergoing involution. External microarray data analysis of mammary tissue further revealed over expression (~16 fold) of QSOX1 gene, which promotes cellular quiescence, in lactating mammary gland. A recent study has indicated that QSOX1 overexpression in breast cancer cells led to reduced proliferation and tumorigenic properties. This extracellular protein in mammary ECM may be responsible for reduced cellular proliferation. The present study has shown that ECM from lactating mammary gland can regulate signals to oral and breast cancer cells to halt cell division. This preliminary observation provided insights into the potential role of ECM factors present in lactating mammary gland as therapeutic targets to control cancer cell division. This preliminary study is an attempt to understand not only the requirement of ECM remodeling factors essential for the growth and survival of cancer cells but also the factors present in the lactation matrix that simultaneously halts cell division and selectively inhibits the growth of cancer cells.

14.
Cell Signal ; 33: 86-97, 2017 05.
Article in English | MEDLINE | ID: mdl-28193539

ABSTRACT

α-lactalbumin is a protein of dual function found in milk of most mammals. α-lactalbumin binds ß-1,4-galactosyltransferase to form the regulatory subunit for lactose synthesis and has also been shown to cause cell death. This study shows, for the first time, that α-lactalbumin isolated in a rare 28kDa dimeric form induces cell death, while 14kDa monomeric α-lactalbumin is inactive. In contrast to the casein derived and chemically induced α-lactalbumin variants, MAL and HAMLET/BAMLET, the effects of 28kDa α-lactalbumin are calcium independent and, unlike MAL and HAMLET, 28kDa α-lactalbumin dimer causes cell death of primary mammary cells and a variety of immortalised cell lines, which are committed to cell death pathways within 1-4h of exposure. Microarray analysis confirmed that cell death was the result of an apoptotic response. Functional assays determined that the mechanism by which 28kDa α-lactalbumin kills cells involved inhibition of histone deacetylase activity mediated by NF-kB. We also show that 28kDa α-lactalbumin occurs naturally in the milk of cows, goats and sheep, is low in concentration during mid-lactation, but accumulates during milk stasis, consistent with a role in involution.


Subject(s)
Activating Transcription Factor 3/metabolism , Apoptosis/drug effects , Histone Deacetylases/metabolism , Lactalbumin/pharmacology , Up-Regulation/drug effects , Amino Acid Sequence , Animals , Cattle , Cell Line, Transformed , Cell Nucleus/drug effects , Cell Nucleus/metabolism , Chromatography, Gel , Goats , Humans , Lactalbumin/chemistry , MCF-7 Cells , Mice , Molecular Weight , NF-kappa B/metabolism , Protein Multimerization , Sheep , Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
15.
Gen Comp Endocrinol ; 244: 164-177, 2017 04 01.
Article in English | MEDLINE | ID: mdl-27528357

ABSTRACT

It is now clear that milk has multiple functions; it provides the most appropriate nutrition for growth of the newborn, it delivers a range of bioactives with the potential to stimulate development of the young, it has the capacity to remodel the mammary gland (stimulate growth or signal cell death) and finally milk can provide protection from infection and inflammation when the mammary gland is susceptible to these challenges. There is increasing evidence to support studies using an Australian marsupial, the tammar wallaby (Macropus eugenii), as an interesting and unique model to study milk bioactives. Reproduction in the tammar wallaby is characterized by a short gestation, birth of immature young and a long lactation. All the major milk constituents change substantially and progressively during lactation and these changes have been shown to regulate growth and development of the tammar pouch young and to have roles in mammary gland biology. This review will focus on recent reports examining the control of lactation in the tammar wallaby and the timed delivery of milk bioactivity.


Subject(s)
Lactation/physiology , Macropodidae/physiology , Milk/metabolism , Animals , Female , Milk/chemistry
16.
Gen Comp Endocrinol ; 242: 38-48, 2017 02 01.
Article in English | MEDLINE | ID: mdl-26673872

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.


Subject(s)
Lactation/physiology , Lactoglobulins/metabolism , Platypus/physiology , Animals , Biological Evolution , Caseins/genetics , Dexamethasone/metabolism , Female , Gene Expression Regulation/physiology , Insulin/metabolism , Lactoglobulins/genetics , Prolactin/metabolism , Promoter Regions, Genetic , Transcription Factors/metabolism
17.
Mech Dev ; 142: 22-29, 2016 11.
Article in English | MEDLINE | ID: mdl-27639961

ABSTRACT

Our research is exploiting the marsupial as a model to understand the signals required for lung development. Marsupials have a unique reproductive strategy, the mother gives birth to altricial neonate with an immature lung and the changes in milk composition during lactation in marsupials appears to provide bioactives that can regulate diverse aspects of lung development, including branching morphogenesis, cell proliferation and cell differentiation. These effects are seen with milk collected between 25 and 100days postpartum. To better understand the temporal effects of milk composition on postnatal lung development we used a cross-fostering technique to restrict the tammar pouch young to milk composition not extending beyond day 25 for 45days of its early postnatal life. These particular time points were selected as our previous study showed that milk protein collected prior to ~day 25 had no developmental effect on mouse embryonic lungs in culture. The comparative analysis of the foster group and control young at day 45 postpartum demonstrated that foster pouch young had significantly reduced lung size. The lungs in fostered young were comprised of large intermediate tissue, had a reduced size of airway lumen and a higher percentage of parenchymal tissue. In addition, expression of marker genes for lung development (BMP4, WNT11, AQP-4, HOPX and SPB) were significantly reduced in lungs from fostered young. Further, to identify the potential bioactive expressed by mammary gland that may have developmental effect on pouch young lungs, we performed proteomics analysis on tammar milk through mass-spectrometry and listed the potential bioactives (PDGF, IGFBP5, IGFBPL1 and EGFL6) secreted in milk that may be involved in regulating pouch young lung development. The data suggest that postnatal lung development in the tammar young is most likely regulated by maternal signalling factors supplied through milk.


Subject(s)
Lung/growth & development , Macropodidae/growth & development , Milk Proteins/metabolism , Milk/metabolism , Animals , Cell Proliferation/genetics , Female , Lung/metabolism , Macropodidae/metabolism , Milk Proteins/genetics , Organogenesis/genetics
18.
Funct Integr Genomics ; 16(3): 297-321, 2016 May.
Article in English | MEDLINE | ID: mdl-26909879

ABSTRACT

The molecular processes underlying human milk production and the effects of mastitic infection are largely unknown because of limitations in obtaining tissue samples. Determination of gene expression in normal lactating women would be a significant step toward understanding why some women display poor lactation outcomes. Here, we demonstrate the utility of RNA obtained directly from human milk cells to detect mammary epithelial cell (MEC)-specific gene expression. Milk cell RNA was collected from five time points (24 h prepartum during the colostrum period, midlactation, two involutions, and during a bout of mastitis) in addition to an involution series comprising three time points. Gene expression profiles were determined by use of human Affymetrix arrays. Milk cells collected during milk production showed that the most highly expressed genes were involved in milk synthesis (e.g., CEL, OLAH, FOLR1, BTN1A1, and ARG2), while milk cells collected during involution showed a significant downregulation of milk synthesis genes and activation of involution associated genes (e.g., STAT3, NF-kB, IRF5, and IRF7). Milk cells collected during mastitic infection revealed regulation of a unique set of genes specific to this disease state, while maintaining regulation of milk synthesis genes. Use of conventional epithelial cell markers was used to determine the population of MECs within each sample. This paper is the first to describe the milk cell transcriptome across the human lactation cycle and during mastitic infection, providing valuable insight into gene expression of the human mammary gland.


Subject(s)
Lactation/genetics , Milk Proteins/genetics , Milk, Human/metabolism , RNA/genetics , Animals , Apoptosis/genetics , Epithelial Cells/metabolism , Female , Gene Expression Regulation , Humans , Mastitis/genetics , Mastitis/pathology , Milk Proteins/biosynthesis , Milk, Human/cytology , Pregnancy , RNA/biosynthesis , RNA/isolation & purification , Signal Transduction/genetics , Transcriptome/genetics
20.
BMC Dev Biol ; 15: 16, 2015 Mar 21.
Article in English | MEDLINE | ID: mdl-25888082

ABSTRACT

BACKGROUND: Marsupials such as the tammar wallaby (M.Eugenii) have a short gestation (29.3 days) and at birth the altricial young resembles a fetus, and the major development occurs postnatally while the young remains in the mother's pouch. The essential functional factors for the maturation of the neonate are provided by the milk which changes in composition progressively throughout lactation (300 days). Morphologically the lungs of tammar pouch young are immature at birth and the majority of their development occurs during the first 100 days of lactation. RESULTS: In this study mouse embryonic lungs (E-12) were cultured in media with tammar skim milk collected at key time points of lactation to identify factors involved in regulating postnatal lung maturation. Remarkably the embryonic lungs showed increased branching morphogenesis and this effect was restricted to milk collected at specific time points between approximately day 40 to 100 lactation. Further analysis to assess lung development showed a significant increase in the expression of marker genes Sp-C, Sp-B, Wnt-7b, BMP4 and Id2 in lung cultures incubated with milk collected at day 60. Similarly, day 60 milk specifically stimulated proliferation and elongation of lung mesenchymal cells that invaded matrigel. In addition, this milk stimulated proliferation of lung epithelium cells on matrigel, and the cells formed 3-dimensional acini with an extended lumen. CONCLUSIONS: This study has clearly demonstrated that tammar wallaby milk collected at specific times in early lactation contains bioactives that may have a significant role in lung maturation of pouch young.


Subject(s)
Lung/embryology , Macropodidae , Milk , Animals , Biomarkers/metabolism , Gene Expression , In Vitro Techniques , Lactation , Lung/metabolism , Mice
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