Limits...
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

α-catenin, β-catenin, and E-cadherin expression in 6 week-old mammary glands. (A) Mammary section hybridized withdigoxigenin-UTP-labeled probe for α-catenin mRNA. Note in end bud tip (ebt), fibroblasts (f), and luminal epithelium (le) express α-catenin. (B–C) Association of α-catenin protein expression and transitional unit (boxed areas) in the TEB. Note in (C), α-catenin expressing cell and cytoneme. (D) 6 week-old mammary section hybridized with digoxigenin-UTP-labeled probe for β-catenin mRNA. (E) β-catenin immunostaining outlines the luminal epithelial cell layer of the 6 week-old TEB. (F) 6 week-old mammary section hybridized with digoxigenin-UTP-labeled probe for E-cadherin mRNA. (G–H) E-cadherin immunostaining in 6 week-old glands. Note E-cadherin expression outlines the luminal epithelial cell layer of the 6 week-old TEB, but negative staining occurs in the transitional unit (boxed area). All sections were collected according to materials and methods. Insets in (A–B, D–G) control probed tissue, respectively. Scale bars (A–B) 50 μm, (C) 24 μm, (D–E) 50 μm, (F–G) 50 μm, and (H) 24 μm.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC129060&req=5

Figure 3: α-catenin, β-catenin, and E-cadherin expression in 6 week-old mammary glands. (A) Mammary section hybridized withdigoxigenin-UTP-labeled probe for α-catenin mRNA. Note in end bud tip (ebt), fibroblasts (f), and luminal epithelium (le) express α-catenin. (B–C) Association of α-catenin protein expression and transitional unit (boxed areas) in the TEB. Note in (C), α-catenin expressing cell and cytoneme. (D) 6 week-old mammary section hybridized with digoxigenin-UTP-labeled probe for β-catenin mRNA. (E) β-catenin immunostaining outlines the luminal epithelial cell layer of the 6 week-old TEB. (F) 6 week-old mammary section hybridized with digoxigenin-UTP-labeled probe for E-cadherin mRNA. (G–H) E-cadherin immunostaining in 6 week-old glands. Note E-cadherin expression outlines the luminal epithelial cell layer of the 6 week-old TEB, but negative staining occurs in the transitional unit (boxed area). All sections were collected according to materials and methods. Insets in (A–B, D–G) control probed tissue, respectively. Scale bars (A–B) 50 μm, (C) 24 μm, (D–E) 50 μm, (F–G) 50 μm, and (H) 24 μm.

Mentions: Stem cells depend upon cell-cell communication in order to undergo division [7]. Important intermediaries in this process are cell adhesion molecules such as α-catenin, E-cadherin, and ZO-1 [21, 22, 30]. To access the location of these molecules immunohistochemistry and in situ Hybridization were carried out in intact nonlabeled mammary glands. Upon examining differences in α-catenin expression in 6 week-old glands, approximately 49% of ductalepithelium expressed this gene (Figure 3A) (Table 1). Luminal cells arranged as transitional units in the TEB also expressed α-catenin mRNA (Figure 3A). α-catenin protein was also expressed in 6 week-old glands, but at very low levels (19%) (Figures 3B and 3C) (Table 1).


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)

α-catenin, β-catenin, and E-cadherin expression in 6 week-old mammary glands. (A) Mammary section hybridized withdigoxigenin-UTP-labeled probe for α-catenin mRNA. Note in end bud tip (ebt), fibroblasts (f), and luminal epithelium (le) express α-catenin. (B–C) Association of α-catenin protein expression and transitional unit (boxed areas) in the TEB. Note in (C), α-catenin expressing cell and cytoneme. (D) 6 week-old mammary section hybridized with digoxigenin-UTP-labeled probe for β-catenin mRNA. (E) β-catenin immunostaining outlines the luminal epithelial cell layer of the 6 week-old TEB. (F) 6 week-old mammary section hybridized with digoxigenin-UTP-labeled probe for E-cadherin mRNA. (G–H) E-cadherin immunostaining in 6 week-old glands. Note E-cadherin expression outlines the luminal epithelial cell layer of the 6 week-old TEB, but negative staining occurs in the transitional unit (boxed area). All sections were collected according to materials and methods. Insets in (A–B, D–G) control probed tissue, respectively. Scale bars (A–B) 50 μm, (C) 24 μm, (D–E) 50 μm, (F–G) 50 μm, and (H) 24 μm.
© Copyright Policy
Related In: Results  -  Collection

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

Figure 3: α-catenin, β-catenin, and E-cadherin expression in 6 week-old mammary glands. (A) Mammary section hybridized withdigoxigenin-UTP-labeled probe for α-catenin mRNA. Note in end bud tip (ebt), fibroblasts (f), and luminal epithelium (le) express α-catenin. (B–C) Association of α-catenin protein expression and transitional unit (boxed areas) in the TEB. Note in (C), α-catenin expressing cell and cytoneme. (D) 6 week-old mammary section hybridized with digoxigenin-UTP-labeled probe for β-catenin mRNA. (E) β-catenin immunostaining outlines the luminal epithelial cell layer of the 6 week-old TEB. (F) 6 week-old mammary section hybridized with digoxigenin-UTP-labeled probe for E-cadherin mRNA. (G–H) E-cadherin immunostaining in 6 week-old glands. Note E-cadherin expression outlines the luminal epithelial cell layer of the 6 week-old TEB, but negative staining occurs in the transitional unit (boxed area). All sections were collected according to materials and methods. Insets in (A–B, D–G) control probed tissue, respectively. Scale bars (A–B) 50 μm, (C) 24 μm, (D–E) 50 μm, (F–G) 50 μm, and (H) 24 μm.
Mentions: Stem cells depend upon cell-cell communication in order to undergo division [7]. Important intermediaries in this process are cell adhesion molecules such as α-catenin, E-cadherin, and ZO-1 [21, 22, 30]. To access the location of these molecules immunohistochemistry and in situ Hybridization were carried out in intact nonlabeled mammary glands. Upon examining differences in α-catenin expression in 6 week-old glands, approximately 49% of ductalepithelium expressed this gene (Figure 3A) (Table 1). Luminal cells arranged as transitional units in the TEB also expressed α-catenin mRNA (Figure 3A). α-catenin protein was also expressed in 6 week-old glands, but at very low levels (19%) (Figures 3B and 3C) (Table 1).

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