Gene expression in the mammary gland of the tammar wallaby during the lactation cycle reveals conserved mechanisms regulating mammalian lactation

2016 ◽  
Vol 28 (9) ◽  
pp. 1241 ◽  
Author(s):  
C. J. Vander Jagt ◽  
J. C. Whitley ◽  
B. G. Cocks ◽  
M. E. Goddard
Keyword(s):  
Gene Expression ◽  
Mammary Gland ◽  
Milk Protein ◽  
Mammary Epithelial Cells ◽  
Tammar Wallaby ◽  
Mammary Epithelial ◽  
Molecular Networks ◽  
Milk Protein Gene ◽  
Milk Protein Gene Expression ◽  
Lactation Cycle

The tammar wallaby (Macropus eugenii), an Australian marsupial, has evolved a different lactation strategy compared with eutherian mammals, making it a valuable comparative model for lactation studies. The tammar mammary gland was investigated for changes in gene expression during key stages of the lactation cycle using microarrays. Differentially regulated genes were identified, annotated and subsequent gene ontologies, pathways and molecular networks analysed. Major milk-protein gene expression changes during lactation were in accord with changes in milk-protein secretion. However, other gene expression changes included changes in genes affecting mRNA stability, hormone and cytokine signalling and genes for transport and metabolism of amino acids and lipids. Some genes with large changes in expression have poorly known roles in lactation. For instance, SIM2 was upregulated at lactation initiation and may inhibit proliferation and involution of mammary epithelial cells, while FUT8 was upregulated in Phase 3 of lactation and may support the large increase in milk volume that occurs at this point in the lactation cycle. This pattern of regulation has not previously been reported and suggests that these genes may play a crucial regulatory role in marsupial milk production and are likely to play a related role in other mammals.

scholarly journals  Gene expression of six major milk proteins in primary bovine mammary epithelial cells isolated from milk during the first twenty weeks of lactation

2012 ◽  
Vol 57 (No. 10) ◽  
pp. 469-480 ◽  
Author(s):  
T. Sigl ◽  
H.H.D. Meyer ◽  
S. Wiedemann
Keyword(s):  
Gene Expression ◽  
Epithelial Cells ◽  
Milk Protein ◽  
Protein Gene ◽  
Mammary Epithelial Cells ◽  
Mammary Epithelial ◽  
Milk Protein Gene ◽  
Bovine Mammary Epithelial Cells ◽  
Milk Protein Genes ◽  
Milk Protein Gene Expression

&nbsp;The objective of the present study was to refine a previously developed method to isolate primary bovine mammary epithelial cells (pBMEC) from fresh milk. Using this method, it was tested whether the number of pBMEC and the relation of recovered pBMEC to total somatic cell count vary within the individual lactation stages. Furthermore, the expression levels of the milk protein genes during the first twenty weeks of lactation were determined by quantitative PCR method. A total number of 152 morning milk samples were obtained from twenty-four Holstein-Friesian cows during the first 20 weeks of lactation (day 8, 15, 26, 43, 57, 113, and 141 postpartum). Numbers of extracted pBMEC were consistent at all time-points (1.1 &plusmn; 0.06 to 1.4 &plusmn; 0.03 &times;10<sup>3</sup>/ml) and an average value of RNA integrity number (RIN) was 6.3 &plusmn; 0.3. Percentage of pBMEC in relation to total milk cells (2.0 &plusmn; 0.2 to 6.7 &plusmn; 1.0%) correlated with milk yield. Expression patterns of the casein genes alpha (&alpha;)<sub>S1</sub>, (&alpha;)<sub>S2</sub>, beta (&beta;), and kappa (&kappa;) (CSN1S1, CSN1S2, CSN2, CSN3, respectively) and the whey protein genes &alpha;-lactalbumin (LALBA) and progestagen-associated endometrial protein (PAEP; known as &beta;-lactoglobulin) were shown to be comparable, i.e. transcripts of all six milk protein genes were found to peak during the first two weeks of lactation and to decline continuously towards mid lactation. However, mRNA levels were different among genes with CSN3 showing the highest and LALBA the lowest abundance. We hypothesized that milk protein gene expression has a pivotal effect on milk protein composition with no influence on milk protein concentration. This paper is the first to describe milk protein gene expression during lactation in pBMEC collected in milk. Future studies will be needed to understand molecular mechanisms in pBMEC including regulation of expression and translation throughout lactation. &nbsp;

scholarly journals Uncoupling the mechanisms that facilitate cell survival in hormone-deprived bovine mammary explants

2008 ◽  
Vol 41 (3) ◽  
pp. 103-116 ◽  
Author(s):  
Amelia J Brennan ◽  
Julie A Sharp ◽  
Christophe M Lefèvre ◽  
Kevin R Nicholas
Keyword(s):  
Gene Expression ◽  
Cell Survival ◽  
Milk Protein ◽  
Protein Gene ◽  
Mammary Epithelial Cells ◽  
Mammary Epithelial ◽  
Milk Protein Gene ◽  
Milk Protein Genes ◽  
Milk Protein Gene Expression ◽  
Lactogenic Hormones

Mammary explants can be hormonally stimulated to mimic the biochemical changes that occur during lactogenesis. Previous studies using mammary explants concluded that the addition of exogenous macromolecules were required for mammary epithelial cells to remain viable in culture. The present study examines the survival of mammary explants from the dairy cow using milk protein gene expression as a functional marker of lactation and cell viability. Mammary explants cultured from late pregnant cows mimicked lactogenesis and showed significantly elevated milk protein gene expression after 3 days of culture with lactogenic hormones. The subsequent removal of exogenous hormones from the media for 10 days resulted in the down-regulation of milk protein genes. During this time, the mammary explants remained hormone responsive, the alveolar architecture was maintained and the expression of milk protein genes was re-induced after a second challenge with lactogenic hormones. We report that a population of bovine mammary epithelial cells have an intrinsic capacity to remain viable and hormone responsive for extended periods in chemically defined media without any exogenous macromolecules. In addition, we found mammary explant viability was dependent on de novo protein and RNA synthesis. Global functional microarray analysis showed that differential expression of genes involved in energy production, immune responses, oxidative stress and apoptosis signalling might contribute to cell survival. As the decline in milk production in dairy cattle after peak lactation results in considerable economic loss, the identification of novel survival genes may be used as genetic markers for breeding programmes to improve lactational persistency in dairy cows.

scholarly journals A population of mammary epithelial cells do not require hormones or growth factors to survive

2008 ◽  
Vol 196 (3) ◽  
pp. 483-496 ◽  
Author(s):  
Amelia J Brennan ◽  
Julie A Sharp ◽  
Elie Khalil ◽  
Matthew R Digby ◽  
Sonia L Mailer ◽  
...  
Keyword(s):  
Gene Expression ◽  
Milk Protein ◽  
Protein Gene ◽  
Mammary Epithelial Cells ◽  
Mammary Epithelial ◽  
Milk Protein Gene ◽  
Culture Model ◽  
Milk Protein Genes ◽  
Milk Protein Gene Expression ◽  
Lactogenic Hormones

Hormonal stimulation of mammary explants mimics many of the biochemical changes observed during lactogenesis. Previous studies using eutherian species conclude that mammary explants require addition of exogenous macromolecules to remain hormone responsive in culture. The present study examines the survival of mammary explants from the wallaby and mouse using milk protein gene expression as a functional marker of lactation and cell viability. Mammary explants from pregnant tammars and mice showed that milk protein gene expression was significantly elevated after 3 days of culture with lactogenic hormones. The subsequent removal of exogenous hormones from the media for 10 days resulted in the down-regulation of milk protein genes. Surprisingly, mammary explants remained hormone responsive and expression of milk protein genes was re-induced after a second challenge with lactogenic hormones. Furthermore, the alveolar architecture was maintained. Global functional microarray analysis showed that classic involution markers were not differentially expressed, although two stress-induced survival genes were significantly up-regulated. We report that a population of mammary epithelial cells have an intrinsic capacity to remain viable and hormone responsive for extended periods in chemically defined media without any exogenous macromolecules. We propose that the mammary explant culture model uncouples the first phase of involution, as milk accumulation that normally provides involution stimuli is absent in this culture model allowing a population of cells to survive.

scholarly journals Suppression of lactation and acceleration of involution in the bovine mammary gland by a selective serotonin reuptake inhibitor

2011 ◽  
Vol 209 (1) ◽  
pp. 45-54 ◽  
Author(s):  
L L Hernandez ◽  
J L Collier ◽  
A J Vomachka ◽  
R J Collier ◽  
N D Horseman
Keyword(s):  
Gene Expression ◽  
Mammary Gland ◽  
Milk Yield ◽  
Milk Protein ◽  
Protein Gene ◽  
Holstein Cows ◽  
Dependent Manner ◽  
Bovine Mammary Gland ◽  
Milk Protein Gene ◽  
Milk Protein Gene Expression

Serotonin (5-HT) is a homeostatic regulator of lactation. Selective 5-HT reuptake inhibitors (SSRI) are commonly prescribed pharmaceuticals that inhibit activity of the 5-HT reuptake transporter, increasing cellular exposure to 5-HT. Use of SSRIs has been shown to alter lactation performance in humans and 5-HT has been shown to reduce milk yield in cattle. However, it has not been determined how SSRI treatments affect the bovine mammary gland. We evaluated the effects of SSRI (fluoxetine (FLX)) administration on tight junctions (TJs) and milk protein gene expression in a lactogenic culture model, using primary bovine mammary epithelial cells (pBMEC). Additionally, we evaluated the effects of intramammary infusions of FLX and 5-hydroxytryptophan on milk production and TJ status in multiparous Holstein cows at dry-off. Treatment of pBMEC cultured on permeable membranes disrupted TJs, as measured by transepithelial resistance and immunostaining for zona occludens 1. Correspondingly, treatment of ‘3D’, collagen-embedded lactogenic cultures of pBMEC with FLX suppressed milk protein gene expression (α-lactalbumin and β-casein) in a concentration-dependent manner. Finally, intramammary treatment of Holstein cows with FLX resulted in an accelerated rate of milk decline. Additionally, TJ permeability increased in FLX-treated animals, as measured by plasma lactose and milk Na+ and K+ levels. Results of these experiments imply that SSRI administration accelerates the rate of mammary gland involution through disassembly of TJs and inhibition of milk protein gene expression in vitro and in vivo, leading to reduction of milk yield.

Progressive changes in milk protein gene expression and prolactin binding during lactation in the tammar wallaby (Macropus eugenii)

1994 ◽  
Vol 13 (2) ◽  
pp. 117-125 ◽  
Author(s):  
P H Bird ◽  
K A K Hendry ◽  
D C Shaw ◽  
C J Wilde ◽  
K R Nicholas
Keyword(s):  
Gene Expression ◽  
Milk Protein ◽  
Protein Gene ◽  
Tammar Wallaby ◽  
Mammary Tissue ◽  
Phase 2 ◽  
Phase 3 ◽  
Milk Protein Gene ◽  
Macropus Eugenii ◽  
Milk Protein Gene Expression

ABSTRACT Changes in milk protein gene expression and specific prolactin binding were quantified in mammary tissue from the tammar wallaby (Macropus eugenii) at different stages of lactation. The transition from early (phase 2) lactation to late (phase 3) lactation was characterized by the induction of the gene for late lactation protein, a novel whey protein. During the same period, the levels of β-lactoglobulin and β-casein gene expression increased, whereas there was no change in the levels of expression of α-lactalbumin and α-casein genes. Prolactin binding in the mammary gland doubled during the latter half of phase 2 of lactation but declined significantly during the transition to phase 3 of lactation. These changes in prolactin binding resulted from changes in the number of receptors and not from a change in the affinity of the receptor for prolactin. Treatment of membranes with concanavalin A increased the number of prolactin-binding sites by 40% in membranes from phase 2 mammary tissue but decreased binding by 40% in membranes from phase 3 tissue, indicating that significant changes had occurred in the membranes of cells during this period. The tammar wallaby can secrete phase 2 and phase 3 milk from adjacent mammary glands (asynchronous concurrent lactation) and the developmental changes in milk protein gene expression and prolactin binding observed during lactation were reflected in these individual glands. Taken collectively, these findings suggest that mammary development and milk secretion in the tammar wallaby are regulated by both endocrine and local (intramammary) mechanisms.

scholarly journals Targeted Expression of GLI1 in the Mammary Gland Disrupts Pregnancy-induced Maturation and Causes Lactation Failure

2007 ◽  
Vol 282 (49) ◽  
pp. 36090-36101 ◽  
Author(s):  
Marie Fiaschi ◽  
Björn Rozell ◽  
Åsa Bergström ◽  
Rune Toftgård ◽  
Marika I. Kleman
Keyword(s):  
Mammary Gland ◽  
Epithelial Cells ◽  
Signaling Pathway ◽  
Hedgehog Signaling ◽  
Mammary Epithelial Cells ◽  
Mammary Epithelial ◽  
Hedgehog Signaling Pathway ◽  
Milk Protein Gene ◽  
Milk Protein Gene Expression ◽  
And Function

The Hedgehog signaling pathway regulates the development and function of numerous tissues and when mis-regulated causes tumorigenesis. To assess the role of a deregulated Hedgehog signaling pathway in the mammary gland we targeted the expression of the Hedgehog effector protein, GLI1, to mammary epithelial cells using a bigenic inducible system. A constitutively active Hedgehog signaling pathway resulted with 100% penetrance in an undifferentiated mammary lobuloalveolar network during pregnancy. GLI1-expressing transgenic females were unable to lactate and milk protein gene expression was essentially absent. The inability to lactate was permanent and independent of continued GLI1 transgene expression. An increased expression of the GLI1 response gene Snail coupled to reduced expression of E-cadherin and STAT5 in the transgenic mammary gland provides a likely molecular explanation, underlying the observed phenotypic changes. In addition, remodeling of the mammary gland after parturition was impaired and expression of GLI1 was associated with accumulation of cellular debris in the mammary ducts during involution, indicating a defect in the clearance of dead cells. Areas with highly proliferative epithelial cells were observed in mammary glands with induced expression of GLI1. Within such areas an increased frequency of cells expressing nuclear Cyclin D1 was observed. Taken together the data support the notion that correct regulation of Hedgehog signaling within the epithelial cell compartment is critical for pregnancy-induced mammary gland development and remodeling.

scholarly journals The effect of growth hormone on milk protein gene expression in the bovine mammary gland

2004 ◽  
Vol 13 (Suppl. 1) ◽  
pp. 437-440 ◽  
Author(s):  
S. McCoard ◽  
N. Roy ◽  
B. Sinclair ◽  
M. Deighton ◽  
W. McNabb
Keyword(s):  
Gene Expression ◽  
Growth Hormone ◽  
Mammary Gland ◽  
Milk Protein ◽  
Protein Gene ◽  
Bovine Mammary Gland ◽  
Milk Protein Gene ◽  
Milk Protein Gene Expression
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