scholarly journals Insulin-like growth factor binding protein-5 (IGFBP-5) induces premature cell death in the mammary glands of transgenic mice

Development ◽  
2002 ◽  
Vol 129 (19) ◽  
pp. 4547-4557 ◽  
Author(s):  
Elizabeth Tonner ◽  
Michael C. Barber ◽  
Gordon J. Allan ◽  
James Beattie ◽  
John Webster ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Cell Death ◽  
Mammary Gland ◽  
Transgenic Mice ◽  
Dna Content ◽  
Caspase 3 ◽  
Transgenic Animals ◽  
Mammary Glands ◽  
Mammary Development ◽  
Igf I

We have previously demonstrated that IGFBP-5 production by mammary epithelial cells increases dramatically during involution of the mammary gland. To demonstrate a causal relationship between IGFBP-5 and cell death we created transgenic mice expressing IGFBP-5 in the mammary gland using a mammary-specific promoter, β-lactoglobulin. DNA content in the mammary glands of transgenic mice was decreased as early as day 10 of pregnancy. Histological analysis indicated reduced numbers of alveolar end buds, with decreased ductal branching. Transgenic dams produced IGFBP-5 in their milk at concentrations similar to those achieved at the end of normal lactation. Mammary cell number and milk synthesis were both decreased by approximately 50% during the first 10 days of lactation. BrdU labelling was decreased, whereas DNA ladders were increased in transgenic animals on day 1 of lactation. On day 2 postpartum, the epithelial invasion of the mammary fat pad was clearly impaired in transgenic animals. The concentrations of the pro-apoptotic molecule caspase-3 and of plasmin were both increased in transgenic animals whilst the concentrations of 2 prosurvival molecules Bcl-2 and Bcl-xLwere both decreased. In order to examine whether IGFBP-5 acts by inhibiting the survival effect of IGF-I we examined IGF receptor phosphorylation and Akt phosphorylation and showed that both were inhibited. We attempted to “rescue” the transgenic phenotype by using growth hormone to increase endogenous IGF-I concentrations or by implanting minipumps delivering an IGF-1 analogue, R3-IGF-1, which binds weakly to IGFBP-5. Growth hormone treatment failed to affect mammary development suggesting that increased concentrations of endogenous IGF-1 are insufficient to overcome the high concentrations of IGFBP-5 produced by these transgenic animals. In contrast mammary development (gland weight and DNA content) was normalised by R3-IGF-I although milk production was only partially restored. This is the first demonstration that over-expression of IGFBP-5 can lead to; impaired mammary development, increased expression of the pro-apoptotic molecule caspase-3, increased plasmin generation and decreased expression of pro-survival molecules of the Bcl-2 family. It clearly demonstrates that IGF-I is an important developmental/survival factor for the mammary gland and, furthermore, this cell death programme may be utilised in a wide variety of tissues.

scholarly journals Altered mammary epithelial development, pattern formation and involution in transgenic mice expressing the EphB4 receptor tyrosine kinase

2002 ◽  
Vol 115 (1) ◽  
pp. 25-37
Author(s):  
Nadia Munarini ◽  
Richard Jäger ◽  
Susanne Abderhalden ◽  
Gisela Zuercher ◽  
Valeria Rohrbach ◽  
...  
Keyword(s):  
Mammary Gland ◽  
Transgenic Mice ◽  
Apoptotic Cell ◽  
Mammary Epithelium ◽  
Transgenic Animals ◽  
Mammary Glands ◽  
Mouse Mammary Gland ◽  
Mammary Epithelial ◽  
Cellular Growth ◽  
Mmtv Ltr

We have previously documented the cell-type-specific and hormone-dependent expression of the EphB4 receptor in the mouse mammary gland. To investigate its role in the biology of the mammary gland, we have established transgenic mice bearing the EphB4 receptor under the control of the MMTV-LTR promoter, which represents the first transgenic mouse model to investigate the effect(s) of unscheduled expression of EphB4 in adult organisms. Transgene expression in the mammary epithelium was induced at puberty, increased during pregnancy, culminated at early lactation and persisted until day three of post-lactational involution. In contrast, expression of the endogenous EphB4 gene is downregulated during pregnancy, is essentially absent during lactation and is re-induced after day three of post-lactational involution. The unscheduled expression of EphB4 led to a delayed development of the mammary epithelium at puberty and during pregnancy. During pregnancy, less lobules were formed, these however exhibited more numerous but smaller alveolar units. Transgenic mammary glands were characterized by a fragile, irregular morphology at lactation; however, sufficient functionality was maintained to nourish the young. Transgenic mammary glands exhibited untimely epithelial apoptotic cell death during pregnancy and abnormal epithelial DNA synthesis at early post-lactational involution, indicating a disturbed response to proliferative/apoptotic signals. Mammary tumours were not observed in the EphB4 transgenic animals; however, in double transgenic animals expressing both EphB4 and the neuT genes, tumour appearance was significantly accelerated and, in contrast to neuT-only animals, metastases were observed in the lung. These results implicate EphB4 in the regulation of tissue architecture, cellular growth response and establishment of the invasive phenotype in the adult mammary gland.

scholarly journals Hyperthyroidism and production of precocious involution in the mammary glands of lactating rats

Reproduction ◽  
2002 ◽  
pp. 691-702 ◽  
Author(s):  
SM Varas ◽  
EM Munoz ◽  
MB Hapon ◽  
CI Aguilera Merlo ◽  
MS Gimenez ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Mammary Gland ◽  
Growth Factor ◽  
Epithelial Cells ◽  
Binding Sites ◽  
Mammary Glands ◽  
Insulin Like Growth Factor ◽  
Mammary Involution ◽  
Igf I ◽  
Mammary Gland Epithelial Cells

This study investigated the influence of chronic hyperthyroidism on mammary function in lactating rats and the effects on their pups. Thyroxine-treated (10 microg per 100 g body weight per day; hyperthyroid (HT)) or vehicle-treated rats were mated 2 weeks after the start of treatment and killed with their litters on days 7, 14 and 21 of lactation. Serum concentrations of triiodothyronine (T(3)) and tetraiodothyronine (T(4)) increased in thyroxine-treated rats. In HT mothers, serum prolactin decreased on day 7 and day 14 of lactation, whereas insulin-like growth factor I (IGF-I) and progesterone concentrations decreased, and corticosterone increased on day 7 of lactation. In HT pups, T(4) concentration increased on day 7 and day 14 of lactation, whereas T(3) increased only on day 14 of lactation, and growth hormone increased on day 7 of lactation. Mammary prolactin binding sites did not vary, but there was an increase in the binding sites in the liver on day 14 of lactation in thyroxine-treated rats. In an acute suckling experiment, thyroxine-treated rats released less oxytocin, growth hormone and prolactin and excreted less milk than did control rats. Mammary casein, lactose and total lipid concentrations in thyroxine-treated rats were similar to those of control rats on day 14 of lactation. Histological studies of the mammary glands showed an increased proportion of alveoli showing reduced or no lumina and cells with condensed nuclei on day 14 and day 21 of lactation; the TdT-mediated dUTP nick-end labelling (TUNEL) test revealed an increase in apoptosis in alveolar cells on day 21 of lactation in thyroxine-treated rats. Expression of SGP-2, a gene expressed during mammary involution, increased in thyroxine-treated rats on day 14 and day 21 of lactation, whereas expression of insulin-like growth factor binding protein 5, a proapoptotic signal, was unchanged. Bcl-2, which promotes survival of mammary gland epithelial cells was unchanged, whereas expression of IGF-I, which also promotes survival of mammary gland epithelial cells, increased on day 21 of lactation in thyroxine-treated rats. These results indicate that thyroxine treatment produces some milk stasis as a result of impairments in suckling induced release of oxytocin that may initiate the first stage of mammary involution, increasing apoptosis in a gland that is otherwise actively producing and secreting milk.

MAMMARY GLAND GROWTH IN MALE MICE OF THE CHI STRAIN AFTER HYPOPHYSECTOMY AND CASTRATION

1958 ◽  
Vol 17 (3) ◽  
pp. 300-NP ◽  
Author(s):  
D. S. FLUX
Keyword(s):  
Growth Hormone ◽  
Mammary Gland ◽  
Mammary Glands ◽  
Mammary Development ◽  
Male Mice ◽  
Mammary Duct

SUMMARY Castrated hypophysectomized male mice of the CHI strain showed a small response in mammary duct growth to injections of oestrone and progesterone. A greater degree of duct growth resulted from the use of growth hormone (GH) in addition to these steroids, and formation of alveoli in addition to duct growth followed treatment with the steroids and prolactin. A greater degree of mammary development, with duct growth and the presence of many alveoli, was seen in mice treated with the steroids and both prolactin and GH. In contrast to the females of this strain, which normally produce ten mammary glands, the males had variable numbers, ranging from none to five.

Expression of bovine β-lactoglobulin transgenic mice

1999 ◽  
Vol 66 (2) ◽  
pp. 289-294 ◽  
Author(s):  
ALFONSO GUTIÉRREZ-ADÁN ◽  
ELIZABETH A. MAGA ◽  
ESMAIL BEHBOODI ◽  
JANICE S. CONRAD-BRINK ◽  
ANTHONY G. MACKINLAY ◽  
...  
Keyword(s):  
Mammary Gland ◽  
Transgenic Mice ◽  
Transgenic Animals ◽  
Milk Composition ◽  
Developmentally Regulated ◽  
Independent Manner ◽  
Milk Protein Genes ◽  
Dairy Animals ◽  
Foreign Proteins ◽  
Β Lactoglobulin

The use of transgenic animals to manipulate milk composition has considerable potential, both for the production of biomedical proteins and for the direct manipulation of milk composition for the improvement of dairy animals and their products (for reviews, see Wall et al. 1992; Yom & Bremel, 1993). Promoters from a number of milk protein genes from a variety of species have been tested for their ability to direct the expression of foreign proteins to the mammary gland (for review, see Maga & Murray, 1995).β-Lactoglobulin (β-lg) is the major whey protein produced in ruminant milk and is part of the normal milk composition of most mammals except humans and rodents (Pervaiz & Brew, 1985). It is expressed at high levels in the mammary gland and is developmentally regulated. Transgenic mice have been produced using the complete ovine (Simons et al. 1987; Shani et al. 1992) and caprine (Ibañez et al. 1997) β-lg genes. In general, high levels of expression were obtained with the ovine β-lg gene, and expression was also seen in a position-independent manner (Whitelaw et al. 1992). Lower levels of expression were reported using the caprine β-lg gene. Here we report the production of transgenic mice using the bovine β-lg gene. We describe high expression, position-dependent, and copy number-related expression of bovine β-lg protein in the milk of six lines of transgenic mice.

Growth hormone and mammary gland lobule-alveolar development

1961 ◽  
Vol 201 (2) ◽  
pp. 259-263 ◽  
Author(s):  
Richard C. Moon
Keyword(s):  
Growth Hormone ◽  
Mammary Gland ◽  
Dna Content ◽  
Deoxyribonucleic Acid ◽  
Cellular Proliferation ◽  
Estradiol Benzoate ◽  
The Mean ◽  
Alveolar Formation ◽  
Inguinal Glands ◽  
Range Of Values

The effect of growth hormone on mammary gland lobule-alveolar growth in the ovariectomized rat was studied using deoxyribonucleic acid (DNA) of the abdominal-inguinal glands as an index of the degree of cellular proliferation. The administration of 1 mg growth hormone in combination with 2 µg estradiol benzoate for 19 days resulted in alveolar formation and an increase in mammary DNA content above that resulting from injections of either hormone alone. The mean DNA concentration of glands of rats treated with 2 µg estradiol, 6 mg progesterone, 3 µg/100 g l-thyroxine, and 0.5, 1.0, 1.5, and 2.0 mg growth hormone was significantly greater than that of animals receiving only the estradiol, progesterone, and thyroxine. The increase in the mean DNA content was due to a shift in the range of values to a higher plane and did not result from an elevated DNA in only a few animals. It is suggested that the administration of growth hormone during the growth phase of the mammary gland may have a beneficial effect on the subsequent lactation.

scholarly journals Temporally regulated overexpression of parathyroid hormone-related protein in the mammary gland reveals distinct fetal and pubertal phenotypes

2001 ◽  
Vol 171 (3) ◽  
pp. 403-416 ◽  
Author(s):  
ME Dunbar ◽  
P Dann ◽  
CW Brown ◽  
J Van Houton ◽  
B Dreyer ◽  
...  
Keyword(s):  
Mammary Gland ◽  
Parathyroid Hormone ◽  
Transgenic Mice ◽  
Mammary Development ◽  
Related Protein ◽  
Parathyroid Hormone Related Protein ◽  
Epithelial Cell Apoptosis ◽  
Ductal Elongation ◽  
Ductal Branching ◽  
Lobuloalveolar Development

We have previously demonstrated that overexpression of parathyroid hormone-related protein (PTHrP) in the mammary glands of transgenic mice results in defects in ductal elongation and branching during puberty and in lobuloalveolar development during pregnancy. In addition, we have shown that PTHrP is necessary for the formation of the initial ductal tree during embryonic mammary development. In order to examine the effect of varying the timing of PTHrP overexpression on mammary development, we created tetracycline-regulated, K14-tTA/Tet(O)-PTHrP double transgenic mice. In this report, we document that this 'tet-off' system directs transgene expression to the mammary gland and that it is fully repressed in the presence of tetracycline. Using these mice, we demonstrate that transient overexpression of PTHrP before birth causes defects in ductal branching during puberty and that overexpression of PTHrP during puberty decreases the rate of ductal elongation. Furthermore, we demonstrate that if PTHrP overexpression is initiated after ductal morphogenesis is completed, lobuloalveolar development is unaffected. Finally, we demonstrate that the impairment in ductal elongation caused by PTHrP is associated with an increase in the basal rate of epithelial cell apoptosis in terminal end buds and a failure to increase end bud cell proliferation and decrease apoptosis in response to estrogen and progesterone.

scholarly journals Reduced mammary gland carcinogenesis in transgenic mice expressing a growth hormone antagonist

2001 ◽  
Vol 85 (3) ◽  
pp. 428-430 ◽  
Author(s):  
M Pollak ◽  
M-J Blouin ◽  
J-C Zhang ◽  
J J Kopchick
Keyword(s):  
Growth Hormone ◽  
Mammary Gland ◽  
Transgenic Mice

scholarly journals The expression of the IGF family and GH receptor in the bovine mammary gland

2001 ◽  
Vol 168 (1) ◽  
pp. 39-48 ◽  
Author(s):  
A Plath-Gabler ◽  
C Gabler ◽  
F Sinowatz ◽  
B Berisha ◽  
D Schams
Keyword(s):  
Mammary Gland ◽  
Binding Proteins ◽  
Mammary Development ◽  
Mammary Tissue ◽  
Bovine Mammary Gland ◽  
Igf Binding Proteins ◽  
Gh Receptor ◽  
Igf I ◽  
Temporal Expressions ◽  
Igfbp 3

To study the involvement of the IGFs in mammary development and lactation of the cow, the temporal expressions of IGF-I and -II, its receptor type 1 (IGFR-1), IGF-binding proteins (IGFBPs)-1 to -6 and GH receptor (GHR) mRNA were examined. This was carried out for different stages of mammogenesis, lactogenesis, galactopoiesis and involution in the bovine mammary gland of 26 animals. Furthermore, IGF-I was localised by immunohistochemistry. The highest mRNA concentrations for IGF-I were detected in the mammary tissue of late pregnant heifers (days 255-272) and significantly lower expression was detected during lactogenesis and galactopoiesis. Immunohistochemistry of IGF-I revealed only a weak staining in the epithelium of the ducts during mammogenesis. The epithelium of the alveoli were negative during mammogenesis, lactogenesis and galactopoiesis but displayed distinct IGF-I activity during involution. In the stroma a distinct staining of the cytoplasm of adipocytes and of vascular smooth muscle cells was observed. A certain percentage of fibroblasts (usually 20-30%) were also immunopositive. In contrast, highest expression for IGFR-1 was detected during galactopoiesis and involution. The lowest mRNA concentration for IGFR-1 was found during pregnancy (days 194-213). In general, the expression of IGF-II was not regulated during mammogenesis and lactation, but decreased during involution. The mRNA for the six binding proteins was detected in the bovine mammary gland. The dominant binding proteins were IGFBP-3 and -5. The highest expression of IGFBP-3 was observed during mid-pregnancy and the lowest during late lactation, involution and in non-pregnant heifers. The mRNA for IGFBP-5 increased during late mammogenesis and lactogenesis followed by a decrease thereafter. In general, the mRNA concentrations for IGFBP-2, -4 and -6 were barely detectable during all stages. In contrast, the expression for IGFBP-1 was upregulated in the mammary gland of virgin heifers and increased around the onset of lactation. mRNA for GHR was found during all stages examined without outstanding fluctuations. In conclusion, locally produced IGF-I and -II may mediate mammogenesis. The high mammary IGFR-1 mRNA during lactation suggests a role for peripheral IGF-I in maintenance of lactation. The role of IGFBPs in the mammary gland needs further evaluation.

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