Differential regulation of GLUT1 and GLUT8 expression by hypoxia in mammary epithelial cells

2014 ◽  
Vol 307 (3) ◽  
pp. R237-R247 ◽  
Author(s):  
Yong Shao ◽  
Theresa L. Wellman ◽  
Karen M. Lounsbury ◽  
Feng-Qi Zhao
Keyword(s):  
Mammary Gland ◽  
Epithelial Cells ◽  
Glucose Uptake ◽  
Mammary Epithelial Cells ◽  
Physiological Mechanism ◽  
Glucose Transporters ◽  
Mammary Glands ◽  
Mammary Development ◽  
Mammary Epithelial ◽  
Early Lactation

Glucose is a major substrate for milk synthesis and is taken up from the blood by mammary epithelial cells (MECs) through facilitative glucose transporters (GLUTs). The expression levels of GLUT1 and GLUT8 are upregulated dramatically in the mammary gland from late pregnancy through early lactation stages. This study aimed to test the hypothesis that this increase in GLUT1 and GLUT8 expression involves hypoxia signaling through hypoxia inducible factor-1α (HIF-1α) in MECs. Mouse mammary glands showed significantly more hypoxia in midpregnancy through early lactation stages compared with in the virgin stage, as stained by the hypoxia marker pimonidazole HCl. Treatment with hypoxia (2% O2) significantly stimulated glucose uptake and GLUT1 mRNA and protein expression, but decreased GLUT8 mRNA expression in bovine MECs. In MECs, hypoxia also increased the levels of HIF-1α protein in the nuclei, and siRNA against HIF-1α completely abolished the hypoxia-induced upregulation of GLUT1, while having no effect on GLUT8 expression. A 5′-RCGTG-3′ core HIF-1α binding sequence was identified 3.7 kb upstream of the bovine GLUT1 gene, and HIF-1α binding to this site was increased during hypoxia. In conclusion, the mammary glands in pregnant and lactating animals are hypoxic, and MECs respond to this hypoxia by increasing GLUT1 expression and glucose uptake through a HIF-1α-dependent mechanism. GLUT8 expression, however, is negatively regulated by hypoxia through a HIF-1α-independent pathway. The regulation of glucose transporters through hypoxia-mediated gene transcription in the mammary gland may provide an important physiological mechanism for MECs to meet the metabolic demands of mammary development and lactation.

scholarly journals Signal Transducer and Activator of Transcription 5a Mediates Mammary Ductal Branching and Proliferation in the Nulliparous Mouse

Endocrinology ◽  
2010 ◽  
Vol 151 (6) ◽  
pp. 2876-2885 ◽  
Author(s):  
Sarah J. Santos ◽  
Sandra Z. Haslam ◽  
Susan E. Conrad
Keyword(s):  
Mammary Gland ◽  
Epithelial Cells ◽  
Mammary Gland Development ◽  
Kinase Inhibitor ◽  
Mammary Epithelial Cells ◽  
Nuclear Factor Κb ◽  
Mammary Glands ◽  
Mammary Epithelial ◽  
Signal Transducer ◽  
Gland Development

Signal transducer and activator of transcription (Stat)5a is a critical regulator of mammary gland development. Previous studies have focused on Stat5a’s role in the late pregnant and lactating gland, and although active Stat5a is detectable in mammary epithelial cells in virgin mice, little is known about its role during early mammary gland development. In this report, we compare mammary gland morphology in pubertal and adult nulliparous wild-type and Stat5a−/− mice. The Stat5a-null mammary glands exhibited defects in secondary and side branching, providing evidence that Stat5a regulates these processes. In addition, Stat5a−/− mammary glands displayed an attenuated proliferative response to pregnancy levels of estrogen plus progesterone (E+P), suggesting that it plays an important role in early pregnancy. Finally, we examined one potential mediator of Stat5a’s effects, receptor activator of nuclear factor-κB ligand (RANKL). Stat5a−/− mammary glands were defective in inducing RANKL in response to E+P treatment. In addition, regulation of several reported RANKL targets, including inhibitor of DNA binding 2 (Id2), cyclin D1, and the cyclin-dependent kinase inhibitor p21Waf1/Cip1, was altered in Stat5a−/− mammary cells, suggesting that one or more of these proteins mediate the effects of Stat5a in E+P-treated mammary epithelial cells.

Differential expression of the growth hormone receptor and growth hormone-binding protein in epithelia and stroma of the mouse mammary gland at various physiological stages

1999 ◽  
Vol 161 (1) ◽  
pp. 77-87 ◽  
Author(s):  
YN Ilkbahar ◽  
G Thordarson ◽  
IG Camarillo ◽  
F Talamantes
Keyword(s):  
Growth Hormone ◽  
Mammary Gland ◽  
Epithelial Cells ◽  
Growth Hormone Receptor ◽  
Mammary Epithelial Cells ◽  
Late Pregnancy ◽  
Mammary Glands ◽  
Mouse Mammary Gland ◽  
Mammary Epithelial ◽  
Mrna Levels

Increasing evidence suggests that GH is important in normal mammary gland development. To investigate this further, we studied the distribution and levels of growth hormone receptor (GHR) and GH-binding protein (GHBP) in the mouse mammary gland. At three weeks of age, the epithelial component of the right fourth inguinal mammary gland of female mice was removed. These animals were then either maintained as virgins until they were killed or they were mated. One group of the mated mice was killed on day 18 of pregnancy and the remaining mated animals were allowed to carry their pups until term and were killed on day 6 of lactation. At the time of death, both the intact left and the de-epithelialized right mammary glands were collected from all three groups. Some of the intact glands served as a source of epithelial cells, free of stroma. The mRNA levels for GHR and GHBP were measured in intact glands, epithelia-cleared fat pads, and isolated mammary epithelial cells. GHR and GHBP mRNAs were expressed in both the mammary epithelium and stroma. However, the levels of both GHR and GHBP mRNAs were significantly higher in the stroma as compared with the epithelium component. This increase for both mRNAs was from 3- to 12-fold at each physiological state examined. In the intact gland, both GHR and GHBP transcripts were highest in virgins, declined during late pregnancy, and the lowest levels were found in the lactating gland. GHBP and GHR protein concentrations were also assessed in intact glands and epithelia-free fat pads. Similar to the mRNAs, GHR and GHBP protein levels (means+/-s.e.m.) in intact glands were highest in virgin mice (0.891+/-0.15 pmoles/mg protein and 0.136+/-0.26 pmoles/mg protein respectively), declined during late pregnancy (0. 354+/-0.111 pmoles/mg protein and 0.178+/-0.039 pmoles/mg protein respectively), and were lowest during lactation (0.096+0.037 pmoles/mg protein and 0.017+0.006 pmoles/mg protein respectively). Immunocytochemistry utilizing specific antisera against mouse (m) GHR and mGHBP revealed that the two proteins are localized to both the stroma and parenchyma of mouse mammary glands, with similar patterns of immunostaining throughout the different physiological stages analyzed. GHR immunolocalized to the plasma membrane and cytosol of mammary epithelial cells and adipocytes, whereas the GHBP immunostaining was nuclear and cytosolic. In conclusion, we report here that GHR and GHBP mRNAs and proteins are expressed in both the epithelium and the stroma of mammary glands of virgin, pregnant, and lactating mice. In intact glands, GHR and GHBP proteins, as well as their transcripts are higher in abundance in virgin relative to lactating mice. At all physiological stages, GHR and GHBP mRNA levels are higher in the stroma compared with the parenchyma. These findings indicate that the actions of GH in the mammary gland are both direct through its binding to the epithelia, and indirect by binding to the stroma and stimulation of IGF-I production which, in turn, affects mammary epithelial development.

Developmental role of the SNF1-related kinase Hunk in pregnancy-induced changes in the mammary gland

Development ◽  
2000 ◽  
Vol 127 (20) ◽  
pp. 4493-4509
Author(s):  
H.P. Gardner ◽  
G.K. Belka ◽  
G.B. Wertheim ◽  
J.L. Hartman ◽  
S.I. Ha ◽  
...  
Keyword(s):  
Mammary Gland ◽  
Epithelial Cells ◽  
Mammary Epithelial Cells ◽  
Mammary Epithelium ◽  
Ovarian Hormones ◽  
Mammary Development ◽  
Mammary Epithelial ◽  
Serine Threonine Kinase ◽  
Proliferation And Differentiation ◽  
Induced Changes

The steroid hormones 17 beta-estradiol and progesterone play a central role in the pathogenesis of breast cancer and regulate key phases of mammary gland development. This suggests that developmental regulatory molecules whose activity is influenced by ovarian hormones may also contribute to mammary carcinogenesis. In a screen designed to identify protein kinases expressed in the mammary gland, we previously identified a novel SNF1-related serine/threonine kinase, Hunk (hormonally upregulated Neu-associated kinase). During postnatal mammary development, Hunk mRNA expression is restricted to a subset of mammary epithelial cells and is temporally regulated with highest levels of expression occurring during early pregnancy. In addition, treatment of mice with 17 beta-estradiol and progesterone results in the rapid and synergistic upregulation of Hunk expression in a subset of mammary epithelial cells, suggesting that the expression of this kinase may be regulated by ovarian hormones. Consistent with the tightly regulated pattern of Hunk expression during pregnancy, mammary glands from transgenic mice engineered to misexpress Hunk in the mammary epithelium manifest temporally distinct defects in epithelial proliferation and differentiation during pregnancy, and fail to undergo normal lobuloalveolar development. Together, these observations suggest that Hunk may contribute to changes in the mammary gland that occur during pregnancy in response to ovarian hormones.

scholarly journals Evidence of Rab3A Expression, Regulation of Vesicle Trafficking, and Cellular Secretion in Response to Heregulin in Mammary Epithelial Cells

2000 ◽  
Vol 20 (23) ◽  
pp. 9092-9101 ◽  
Author(s):  
Ratna K. Vadlamudi ◽  
Rui-An Wang ◽  
Amjad H. Talukder ◽  
Liana Adam ◽  
Randy Johnson ◽  
...  
Keyword(s):  
Mammary Gland ◽  
Epithelial Cells ◽  
Mammary Epithelial Cells ◽  
Vesicle Trafficking ◽  
Mammary Epithelial ◽  
Coated Vesicle ◽  
Human Breast ◽  
Breast Epithelial Cells ◽  
Breast Epithelial ◽  
Stimulation Of

ABSTRACT Heregulin β1 (HRG), a combinatorial ligand for human growth factor receptors 3 and 4, is a regulatory polypeptide that promotes the differentiation of mammary epithelial cells into secretory lobuloalveoli. Emerging evidence suggests that the processes of secretory pathways, such as biogenesis and trafficking of vesicles in neurons and adipose cells, are regulated by the Rab family of low-molecular-weight GTPases. In this study, we identified Rab3A as a gene product induced by HRG. Full-length Rab3A was cloned from a mammary gland cDNA library. We demonstrated that HRG stimulation of human breast cancer cells and normal breast epithelial cells induces the expression of Rab3A protein and mRNA in a cycloheximide-independent manner. HRG-mediated induction of Rab3A expression was blocked by an inhibitor of phosphatidylinositol 3-kinase but not by inhibitors of mitogen-activated protein kinases p38MAPK and p42/44MAPK. Human breast epithelial cells also express other components of regulated vesicular traffic, such as rabphilin 3A, Doc2, and syntaxin. Rab3A was predominantly localized in the cytosol, and HRG stimulation of the epithelial cells also raised the level of membrane-bound Rab3A. HRG treatment induced a profound alteration in the cell morphology in which cells displayed neuron-like membrane extensions that contained Rab3A-coated, vesicle-like structures. In addition, HRG also promoted the secretion of cellular proteins from the mammary epithelial cells. The ability of HRG to modify exocytosis was verified by using a growth hormone transient-transfection system. Analysis of mouse mammary gland development revealed the expression of Rab3A in mammary epithelial cells. Furthermore, expression of the HRG transgene in Harderian tumors in mice also enhanced the expression of Rab3A. These observations provide new evidence of the existence of a Rab3A pathway in mammary epithelial cells and suggest that it may play a role in vesicle trafficking and secretion of proteins from epithelial cells in response to stimulation by the HRG expressed within the mammary mesenchyma.

Expression of lncRNAs in response to bacterial infections of goat mammary epithelial cells reveals insights into mammary gland diseases

2021 ◽  
pp. 105367
Author(s):  
Peerzada Tajamul Mumtaz ◽  
Qamar Taban ◽  
Basharat Bhat ◽  
Syed Mudasir Ahmad ◽  
Mashooq Ahmad Dar ◽  
...  
Keyword(s):  
Mammary Gland ◽  
Epithelial Cells ◽  
Bacterial Infections ◽  
Mammary Epithelial Cells ◽  
Mammary Epithelial ◽  
Goat Mammary Epithelial Cells

MicroRNA-432 inhibits milk fat synthesis by targeting SCD and LPL in ovine mammary epithelial cells

2021 ◽  
Author(s):  
Zhiyun Hao ◽  
Yuzhu Luo ◽  
Jiqing Wang ◽  
Jon Hickford ◽  
Huitong Zhou ◽  
...  
Keyword(s):  
Mammary Gland ◽  
Epithelial Cells ◽  
Milk Production ◽  
Milk Fat ◽  
Mammary Epithelial Cells ◽  
Mammary Epithelial ◽  
Differentially Expressed ◽  
Differentially Expressed Mirnas ◽  
Fat Synthesis ◽  
Milk Fat Synthesis

In our previous studies, microRNA-432 (miR-432) was found to be one of differentially expressed miRNAs in ovine mammary gland between the two breeds of lactating sheep with different milk production...

Bovine mammary epithelial cells, initiators of innate immune responses to mastitis

2005 ◽  
Vol 45 (8) ◽  
pp. 757 ◽  
Author(s):  
C. Gray ◽  
Y. Strandberg ◽  
L. Donaldson ◽  
R. L. Tellam
Keyword(s):  
Immune Response ◽  
Mammary Gland ◽  
Epithelial Cells ◽  
Mammary Epithelial Cells ◽  
Vital Role ◽  
Mammary Epithelial ◽  
Innate Immune ◽  
Mammary Tissue ◽  
Effector Cells ◽  
Bovine Mammary Epithelial Cells

Innate immunity plays a vital role in the protection of the bovine mammary gland against mastitis. Until recently, the migration of effector cells such as neutrophils and monocytes into the mammary gland was thought to provide the only defence against invading pathogens. However, mammary epithelial cells may also play an important role in the immune response, contributing to the innate defence of the mammary tissue through secretion of antimicrobial peptides and attraction of circulating immune effector cells. This paper reviews the innate immune pathways in mammary epithelial cells and examines their role in the initiation of an innate immune response to Gram-positive and Gram-negative bacteria.

scholarly journals Chemerin Regulates Epithelial Barrier Function of Mammary Glands in Dairy Cows

Animals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 3194
Author(s):  
Yutaka Suzuki ◽  
Sachi Chiba ◽  
Koki Nishihara ◽  
Keiichi Nakajima ◽  
Akihiko Hagino ◽  
...  
Keyword(s):  
Mammary Gland ◽  
Epithelial Cell ◽  
Epithelial Cells ◽  
Dairy Cows ◽  
Barrier Function ◽  
Mammary Epithelial Cells ◽  
Mammary Epithelial ◽  
Epithelial Barrier ◽  
Epithelial Tissue ◽  
Epithelial Barrier Function

Epithelial barrier function in the mammary gland acts as a forefront of the defense mechanism against mastitis, which is widespread and a major disorder in dairy production. Chemerin is a chemoattractant protein with potent antimicrobial ability, but its role in the mammary gland remains unelucidated. The aim of this study was to determine the function of chemerin in mammary epithelial tissue of dairy cows in lactation or dry-off periods. Mammary epithelial cells produced chemerin protein, and secreted chemerin was detected in milk samples. Chemerin treatment promoted the proliferation of cultured bovine mammary epithelial cells and protected the integrity of the epithelial cell layer from hydrogen peroxide (H2O2)-induced damage. Meanwhile, chemerin levels were higher in mammary tissue with mastitis. Tumor necrosis factor alpha (TNF-α) strongly upregulated the expression of the chemerin-coding gene (RARRES2) in mammary epithelial cells. Therefore, chemerin was suggested to support mammary epithelial cell growth and epithelial barrier function and to be regulated by inflammatory stimuli. Our results may indicate chemerin as a novel therapeutic target for diseases in the bovine mammary gland.

scholarly journals p19ARFDetermines the Balance between Normal Cell Proliferation Rate and Apoptosis during Mammary Gland Development

2004 ◽  
Vol 15 (5) ◽  
pp. 2302-2311 ◽  
Author(s):  
Yijun Yi ◽  
Anne Shepard ◽  
Frances Kittrell ◽  
Biserka Mulac-Jericevic ◽  
Daniel Medina ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Mammary Gland ◽  
Epithelial Cells ◽  
Protein Level ◽  
Normal Cell ◽  
Mammary Gland Development ◽  
Mammary Epithelial Cells ◽  
Mammary Epithelial ◽  
Proliferation Rate ◽  
Gland Development

This study demonstrated, for the first time, the following events related to p19ARFinvolvement in mammary gland development: 1) Progesterone appears to regulate p19ARFin normal mammary gland during pregnancy. 2) p19ARFexpression levels increased sixfold during pregnancy, and the protein level plateaus during lactation. 3) During involution, p19ARFprotein level remained at high levels at 2 and 8 days of involution and then, declined sharply at day 15. Absence of p19ARFin mammary epithelial cells leads to two major changes, 1) a delay in the early phase of involution concomitant with downregulation of p21Cip1and decrease in apoptosis, and 2) p19ARFnull cells are immortal in vivo measured by serial transplantion, which is partly attributed to complete absence of p21Cip1compared with WT cells. Although, p19ARFis dispensable in mammary alveologenesis, as evidenced by normal differentiation in the mammary gland of pregnant p19ARFnull mice, the upregulation of p19ARFby progesterone in the WT cells and the weakness of p21Cip1in mammary epithelial cells lacking p19ARFstrongly suggest that the functional role(s) of p19ARFin mammary gland development is critical to sustain normal cell proliferation rate during pregnancy and normal apoptosis in involution possibly through the p53-dependent pathway.

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