Myoepithelial cell

About: Myoepithelial cell is a research topic. Over the lifetime, 4783 publications have been published within this topic receiving 157215 citations. The topic is also known as: myoepithelial cell.

Generation of a functional mammary gland from a single stem cell

Abstract: The existence of mammary stem cells (MaSCs) has been postulated from evidence that the mammary gland can be regenerated by transplantation of epithelial fragments in mice. Interest in MaSCs has been further stimulated by their potential role in breast tumorigenesis. However, the identity and purification of MaSCs has proved elusive owing to the lack of defined markers. We isolated discrete populations of mouse mammary cells on the basis of cell-surface markers and identified a subpopulation (Lin-CD29hiCD24+) that is highly enriched for MaSCs by transplantation. Here we show that a single cell, marked with a LacZ transgene, can reconstitute a complete mammary gland in vivo. The transplanted cell contributed to both the luminal and myoepithelial lineages and generated functional lobuloalveolar units during pregnancy. The self-renewing capacity of these cells was demonstrated by serial transplantation of clonal outgrowths. In support of a potential role for MaSCs in breast cancer, the stem-cell-enriched subpopulation was expanded in premalignant mammary tissue from MMTV-wnt-1 mice and contained a higher number of MaSCs. Our data establish that single cells within the Lin-CD29hiCD24+ population are multipotent and self-renewing, properties that define them as MaSCs.

Generation of a functional mammary gland from a single stem cell

Abstract: 4839 The mammary gland can be functionally regenerated in mice by serial transplantation of epithelial fragments, providing evidence for the existence of self-renewing, multipotential mammary stem cells (MaSCs). Recently the concept has emerged that MaSCs play a central role in breast tumorigenesis. However, the identity and purification of MaSC has proved elusive due to the lack of defined markers. Using specific cell surface markers and flow cytometry, we have identified a distinct subpopulation that is enriched for MaSCs, demonstrated by transplantation into cleared mammary fat pads at limiting dilution. Remarkably, a single mammary epithelial cell from this population, carrying the lacZ transgene, was found to generate a complete mammary gland in vivo. These cells contributed to both the luminal and myoepithelial lineages in transplanted virgin mammary glands, and extensive lobuloalveolar units were generated during pregnancy. Serial transplantation of the clonal outgrowths also yielded complete mammary glands, confirming that the cells were capable of self-renewal. These data establish that single cells from the enriched population have multipotential and self-renewing capacity, a hallmark of stem cells. It will be of interest to determine whether the stem cell is a target of transformation mammary tumorigenesis models.

A monoclonal antibody against alpha-smooth muscle actin: a new probe for smooth muscle differentiation.

Abstract: A monoclonal antibody (anti-alpha sm-1) recognizing exclusively alpha-smooth muscle actin was selected and characterized after immunization of BALB/c mice with the NH2-terminal synthetic decapeptide of alpha-smooth muscle actin coupled to keyhole limpet hemocyanin. Anti-alpha sm-1 helped in distinguishing smooth muscle cells from fibroblasts in mixed cultures such as rat dermal fibroblasts and chicken embryo fibroblasts. In the aortic media, it recognized a hitherto unknown population of cells negative for alpha-smooth muscle actin and for desmin. In 5-d-old rats, this population is about half of the medial cells and becomes only 8 +/- 5% in 6-wk-old animals. In cultures of rat aortic media SMCs, there is a progressive increase of this cell population together with a progressive decrease in the number of alpha-smooth muscle actin-containing stress fibers per cell. Double immunofluorescent studies carried out with anti-alpha sm-1 and anti-desmin antibodies in several organs revealed a heterogeneity of stromal cells. Desmin-negative, alpha-smooth muscle actin-positive cells were found in the rat intestinal muscularis mucosae and in the dermis around hair follicles. Moreover, desmin-positive, alpha-smooth muscle actin-negative cells were identified in the intestinal submucosa, rat testis interstitium, and uterine stroma. alpha-Smooth muscle actin was also found in myoepithelial cells of mammary and salivary glands, which are known to express cytokeratins. Finally, alpha-smooth muscle actin is present in stromal cells of mammary carcinomas, previously considered fibroblastic in nature. Thus, anti-alpha sm-1 antibody appears to be a powerful probe in the study of smooth muscle differentiation in normal and pathological conditions.

Eccrine spiradenoma. An electron microscopic study.

Abstract: Electron-microscopic studies of two typical lesions of eccrine spiradenoma were performed to correlate ultrastructure and histopathology. The salient ultramorphological features of the parenchyma were an adenoid cystic organization composed of epithelial, myoepithelial, and nonepithelial cell types, and the presence of intracytoplasmic luminae within the epithelial cells. There were no indications that the parenchyma was secretorily active. The stroma ramified through the parenchyma, occupying extensive areas and forming tenuous septa of the loose connective tissue in which blood vessels and nerve fibers were embedded. Profiles of cystoid spaces resulting from invagination of stroma into the parenchyma were frequently encountered. Based on our observations, eccrine spiradenoma appears to differentiate toward ductal structures of eccrine sweat apparatus.