scholarly journals Parathyroid Hormone-Related Protein Specifies the Mammary Mesenchyme and Regulates Embryonic Mammary Development

2013 ◽  
Vol 18 (2) ◽  
pp. 171-177 ◽  
Author(s):  
Minoti Hiremath ◽  
John Wysolmerski

Development ◽  
2001 ◽  
Vol 128 (4) ◽  
pp. 513-525 ◽  
Author(s):  
J. Foley ◽  
P. Dann ◽  
J. Hong ◽  
J. Cosgrove ◽  
B. Dreyer ◽  
...  

Prior reports have demonstrated that both parathyroid hormone-related protein (PTHrP) and the type I PTH/PTHrP receptor are necessary for the proper development of the embryonic mammary gland in mice. Using a combination of loss-of-function and gain-of-function models, we now report that PTHrP regulates a series of cell fate decisions that are central to the survival and morphogenesis of the mammary epithelium and the formation of the nipple. PTHrP is made in the epithelial cells of the mammary bud and, during embryonic mammary development, it interacts with the surrounding mesenchymal cells to induce the formation of the dense mammary mesenchyme. In response, these mammary-specific mesenchymal cells support the maintenance of mammary epithelial cell fate, trigger epithelial morphogenesis and induce the overlying epidermis to form the nipple. In the absence of PTHrP signaling, the mammary epithelial cells revert to an epidermal fate, no mammary ducts are formed and the nipple does not form. In the presence of diffuse epidermal PTHrP signaling, the ventral dermis is transformed into mammary mesenchyme and the entire ventral epidermis becomes nipple skin. These alterations in cell fate require that PTHrP be expressed during development and they require the presence of the PTH/PTHrP receptor. Finally, PTHrP signaling regulates the epidermal and mesenchymal expression of LEF1 and (β)-catenin, suggesting that these changes in cell fate involve an interaction between the PTHrP and Wnt signaling pathways.



Development ◽  
1999 ◽  
Vol 126 (16) ◽  
pp. 3485-3493
Author(s):  
M.E. Dunbar ◽  
P.R. Dann ◽  
G.W. Robinson ◽  
L. Hennighausen ◽  
J.P. Zhang ◽  
...  

Male mice lack mammary glands due to the interaction of circulating androgens with local epithelial-mesenchymal signaling in the developing mammary bud. Mammary epithelial cells induce androgen receptor (AR) within the mammary mesenchyme and, in response to androgens, the mesenchyme condenses around the epithelial bud, destroying it. We show that this process involves apoptosis and that, in the absence of parathyroid hormone-related protein (PTHrP) or its receptor, the PTH/PTHrP receptor (PPR1), it fails due to a lack of mesenchymal AR expression. In addition, the expression of tenascin C, another marker of the mammary mesenchyme, is also dependent on PTHrP. PTHrP expression is initiated on E11 and, within the ventral epidermis, is restricted to the forming mammary epithelial bud. In contrast, PPR1 expression is not limited to the mammary bud, but is found generally within the subepidermal mesenchyme. Finally, transgenic overexpression of PTHrP within the basal epidermis induces AR and tenasin C expression within the ventral dermis, suggesting that ectopic expression of PTHrP can induce the ventral mesenchyme to express mammary mesenchyme markers. We propose that PTHrP expression specifically within the developing epithelial bud acts as a dominant signal participating in cell fate decisions leading to a specialized mammary mesenchyme.



2001 ◽  
Vol 171 (3) ◽  
pp. 403-416 ◽  
Author(s):  
ME Dunbar ◽  
P Dann ◽  
CW Brown ◽  
J Van Houton ◽  
B Dreyer ◽  
...  

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.



Development ◽  
2012 ◽  
Vol 139 (22) ◽  
pp. 4239-4249 ◽  
Author(s):  
M. Hiremath ◽  
P. Dann ◽  
J. Fischer ◽  
D. Butterworth ◽  
K. Boras-Granic ◽  
...  




Hypertension ◽  
1996 ◽  
Vol 27 (3) ◽  
pp. 360-363 ◽  
Author(s):  
Bingbing Jiang ◽  
Shigeto Morimoto ◽  
Keisuke Fukuo ◽  
Atsushi Hirotani ◽  
Michio Tamatani ◽  
...  


Hypertension ◽  
1997 ◽  
Vol 30 (4) ◽  
pp. 922-927 ◽  
Author(s):  
Bingbing Jiang ◽  
Shigeto Morimoto ◽  
Jin Yang ◽  
Keisuke Fukuo ◽  
Atsushi Hirotani ◽  
...  


1989 ◽  
Vol 264 (25) ◽  
pp. 14806-14811
Author(s):  
R G Hammonds ◽  
P McKay ◽  
G A Winslow ◽  
H Diefenbach-Jagger ◽  
V Grill ◽  
...  


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