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Identification of Stem Cell Units in the Terminal End Bud and Duct of the Mouse Mammary Gland.

Kenney NJ, Smith GH, Lawrence E, Barrett JC, Salomon DS - J. Biomed. Biotechnol. (2001)

Bottom Line: Additionally, TUs are located every 250 +/- 75 &mgr;m in ducts or in the terminal end bud 200-600 &mgr;m in diameter.Molecules expressed in TUs were Zonula Occludens-1 and alpha-catenin proteins which were significantly detected in 75%-91% (P <0.001)of the LRCs cells that make up the TU.These data suggest that transitional units may be a group of label-retaining stem cells and maybe involved in the developmental or cancer process.

View Article: PubMed Central - HTML - PubMed

ABSTRACT
The mouse mammary gland may undergo cycles of proliferation, terminal differentiation, tissue remodeling, and more importantly malignant transformation.Mammary epithelial stem cells and their progeny participate in these processes.Mammary epithelial stem cells are multipotent, exhibit properties of self renewal (up to 7 divisions)and may exist either as long-lived nondividing cells or as proliferating-differentiating cells. The focus of this study was to locate stem cells by identifying them as long-lived, label-retaining mammary epithelial cells (LRCs)in growth active (developing)or growth static (aged)mammary ducts. Initially, primary epithelial cells were pulse labeled with either fluorescent tracker dye and/or BrdU. Cells were then transplanted into cleared juvenile syngeneic mammary fat pads and held for 5 weeks or 8 weeks. In this study, we demonstrate that LRCs are stem cells and their progeny (transitional cells)are arranged as transitional units (TUs). Additionally, TUs are located every 250 +/- 75 &mgr;m in ducts or in the terminal end bud 200-600 &mgr;m in diameter. Molecules expressed in TUs were Zonula Occludens-1 and alpha-catenin proteins which were significantly detected in 75%-91% (P <0.001)of the LRCs cells that make up the TU. These data suggest that transitional units may be a group of label-retaining stem cells and maybe involved in the developmental or cancer process.

No MeSH data available.


Related in: MedlinePlus

Confocal 3D microscopic image of bright TRITC labeled-retaining cells in 5 week-old FVB/N TEB. (A) 3D microscopic image of bright TRITC labeled-retaining cells. Note the location of bright LRCs and a TUs (arrow). (B) Laser sections represent en face views of serial sections that were recorded at 0.7 μm intervals. Three dimensional image and optical serial sections were generated and processed according to materials and methods. Scale bars in (A), (B) 260 μm.
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Figure 2: Confocal 3D microscopic image of bright TRITC labeled-retaining cells in 5 week-old FVB/N TEB. (A) 3D microscopic image of bright TRITC labeled-retaining cells. Note the location of bright LRCs and a TUs (arrow). (B) Laser sections represent en face views of serial sections that were recorded at 0.7 μm intervals. Three dimensional image and optical serial sections were generated and processed according to materials and methods. Scale bars in (A), (B) 260 μm.

Mentions: To examine the arrangement of LRCs along the mammary duct,portions of 5 week-old ducts and TEBs were assessed using 3-dimensional (3D) confocal microscopy. The results suggest that bright TLC-LRCs were detected at the tip of the TEB, and in areas of the subtending duct (Figure 2). Interestingly, TLC-LRCs also appeared to be grouped as aggregates or transitional units (TUs) (Figure 2 arrow). We further examined these units by 3D montage photography and determined that within the TU at least one bright LRC is usually in contact with another LRC by long thin processes referred to as cytonemes (photomicrographs notshown). Cytonemes, cellular processes that may span several cell diameters have been implicated in dispersing signaling proteins such as Hedgehog (Hh), Decapentaplegic (Dpp) and Wingless during Drosophila imaginal disc development or chick limb-bud development.


Identification of Stem Cell Units in the Terminal End Bud and Duct of the Mouse Mammary Gland.

Kenney NJ, Smith GH, Lawrence E, Barrett JC, Salomon DS - J. Biomed. Biotechnol. (2001)

Confocal 3D microscopic image of bright TRITC labeled-retaining cells in 5 week-old FVB/N TEB. (A) 3D microscopic image of bright TRITC labeled-retaining cells. Note the location of bright LRCs and a TUs (arrow). (B) Laser sections represent en face views of serial sections that were recorded at 0.7 μm intervals. Three dimensional image and optical serial sections were generated and processed according to materials and methods. Scale bars in (A), (B) 260 μm.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC129060&req=5

Figure 2: Confocal 3D microscopic image of bright TRITC labeled-retaining cells in 5 week-old FVB/N TEB. (A) 3D microscopic image of bright TRITC labeled-retaining cells. Note the location of bright LRCs and a TUs (arrow). (B) Laser sections represent en face views of serial sections that were recorded at 0.7 μm intervals. Three dimensional image and optical serial sections were generated and processed according to materials and methods. Scale bars in (A), (B) 260 μm.
Mentions: To examine the arrangement of LRCs along the mammary duct,portions of 5 week-old ducts and TEBs were assessed using 3-dimensional (3D) confocal microscopy. The results suggest that bright TLC-LRCs were detected at the tip of the TEB, and in areas of the subtending duct (Figure 2). Interestingly, TLC-LRCs also appeared to be grouped as aggregates or transitional units (TUs) (Figure 2 arrow). We further examined these units by 3D montage photography and determined that within the TU at least one bright LRC is usually in contact with another LRC by long thin processes referred to as cytonemes (photomicrographs notshown). Cytonemes, cellular processes that may span several cell diameters have been implicated in dispersing signaling proteins such as Hedgehog (Hh), Decapentaplegic (Dpp) and Wingless during Drosophila imaginal disc development or chick limb-bud development.

Bottom Line: Additionally, TUs are located every 250 +/- 75 &mgr;m in ducts or in the terminal end bud 200-600 &mgr;m in diameter.Molecules expressed in TUs were Zonula Occludens-1 and alpha-catenin proteins which were significantly detected in 75%-91% (P <0.001)of the LRCs cells that make up the TU.These data suggest that transitional units may be a group of label-retaining stem cells and maybe involved in the developmental or cancer process.

View Article: PubMed Central - HTML - PubMed

ABSTRACT
The mouse mammary gland may undergo cycles of proliferation, terminal differentiation, tissue remodeling, and more importantly malignant transformation.Mammary epithelial stem cells and their progeny participate in these processes.Mammary epithelial stem cells are multipotent, exhibit properties of self renewal (up to 7 divisions)and may exist either as long-lived nondividing cells or as proliferating-differentiating cells. The focus of this study was to locate stem cells by identifying them as long-lived, label-retaining mammary epithelial cells (LRCs)in growth active (developing)or growth static (aged)mammary ducts. Initially, primary epithelial cells were pulse labeled with either fluorescent tracker dye and/or BrdU. Cells were then transplanted into cleared juvenile syngeneic mammary fat pads and held for 5 weeks or 8 weeks. In this study, we demonstrate that LRCs are stem cells and their progeny (transitional cells)are arranged as transitional units (TUs). Additionally, TUs are located every 250 +/- 75 &mgr;m in ducts or in the terminal end bud 200-600 &mgr;m in diameter. Molecules expressed in TUs were Zonula Occludens-1 and alpha-catenin proteins which were significantly detected in 75%-91% (P <0.001)of the LRCs cells that make up the TU. These data suggest that transitional units may be a group of label-retaining stem cells and maybe involved in the developmental or cancer process.

No MeSH data available.


Related in: MedlinePlus