College of Agriculture & Natural Resources

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Subject: search.filters.subject.Mammary stem cell

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    In vitro expansion of the mammary stem/progenitor cell population by xanthosine treatment
    (Springer Nature, 2012-06-14) Choudhary, Ratan K; Capuco, Anthony V
    Mammary stem cells are critical for growth and maintenance of the mammary gland and therefore are of considerable interest for improving productivity and efficiency of dairy animals. Xanthosine treatment has been demonstrated to promote expansion of putative mammary stem cells in vivo, and hepatic and hair follicle stem cells in vitro. In the latter, xanthosine promoted the symmetrical division of hepatic and hair follicle stem cells. The objective of this study was to determine if treating primary cultures of bovine mammary epithelial cells (MEC) with xanthosine increases the stem/progenitor cell population by promoting symmetrical division of mammary stem cells. In vitro treatment with xanthosine increased the population of MEC during the exponential phase of cell growth, reducing the doubling time from 86 h in control cultures to 60 h in xanthosine-treated cultures. The bromodeoxyuridine (BrdU) labeling index and the proportion of MEC in S-phase both were increased by xanthosine treatment, indicating that increased cell accretion was due to increased cell proliferation. Analysis of daughter-pairs indicated that xanthosine promoted a shift from asymmetric to symmetric cell division. Moreover, the 30 % increase in symmetric cell division was concomitant with an increase in the proportion of MEC that were positive for a putative stem cell marker (FNDC3B) and a trend toward increased telomerase activity. These results suggest that xanthosine treatment in vitro can increase cell proliferation, promote symmetric cell division and enhance stem/progenitor cell activity. Xanthosine treatment increased the proliferation rate of bovine MEC in vitro. This was likely to be mediated by an increase in the proportion of stem/progenitor cells in the MEC population due to promotion of symmetrical stem cell division by xanthosine.
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    Identification and characterization of presumptive bovine mammary stem cells
    (2011) Choudhary, Ratan Kumar; Capuco, Anthony V; Mather, Ian H; Animal Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
    An understanding of the characteristics and regulation of mammary stem cells (MaSCs) is needed to gain insight into normal gland development and carcinogenesis. Previous profiling of MaSCs relied upon immunophenotypic selection of enzymatically dispersed cells by flow cytometry. However, these approaches involved the selection of cells that are removed from their tissue location and cellular microenvironment. In this study, I have utilized an alternative approach called laser microdissection, to excise putative MaSCs, based upon their ability to retain bromodeoxyuridine labeled DNA for an extended period, and control cells from their in situ locations in prepubertal bovine mammary cryosections. First, I established a protocol to immunostain putative MaSCs in tissue cryosections and isolate RNA of high quality. Next, I excised putative MaSCs and control cells from immunostained cryosections using laser microdissection. Global gene expression analysis by microarray provided evidence that MaSCs were located in the basal epithelium and progenitor cells located in suprabasal layers. A number of genes that were up-regulated in MaSCs and progenitor cells were identified and these are potential biomarkers. Analysis of the expression pattern of four genes (NR5A2, NUP153, HNF4A and FNDC3B) by immunohistochemistry showed that the protein expression profile was consistent with microarray data. Detailed immunohistochemical analyses of NR5A2, NUP153, HNF4A and FNDC3B in calf and cows (at various stages of lactation) revealed that their frequency and distribution were consistent with stem/progenitor cell characteristics. Finally, I attempted to manipulate stem/progenitor cells number using cultures of primary mammary epithelial cells. Expansion of stem/progenitor cell is a prerequisite for stem cell therapeutics and facilitates stem cell research. The effect of xanthosine on bovine mammary epithelial cells (MEC) was evaluated. The result of this study showed that xanthosine treatment increased cell proliferation, promoted symmetric cell division and increased expression of telomerase and a novel stem cell marker (FNDC3B). Together, these studies identified novel, potential markers for MaSCs and progenitor cells, and supported the ability of xanthosine to increase stem/progenitor cell number.