Moraga Biotech Blog http://moragabiotech.com/nucleus/ en-us Nucleus CMS v3.23 © Weblog http://backend.userland.com/rss http://moragabiotech.com/nucleus//nucleus/nucleus2.gif Moraga Biotech Blog http://moragabiotech.com/nucleus/ p63-Expressing Cells are the Stem Cell of Developing Prostate, Bladder, and Colorectal Epithelia http://moragabiotech.com/nucleus/index.php?itemid=1526 PNAS, J.-C. Pignon et al. from Harvard Medical School published their study results on determining whether the tumor protein p63 is a marker for stem cells. The investigators used the amino terminal truncated ( N) p63 isoform as a marker for epithelial stem cells. N is a marker of basal epithelial cells and its expression is required for normal development of several epithelial tissues. The researchers used N knock-in transgenic mice ( Np63+/Cre) for genetic lineage tracing for Np63-expressing cells of the caudal endoderm in vivo. The study data revealed that Np63-expressing cells in the urogenital sinus gave rise to all epithelial lineages of the prostrate and bladder. Additionally, Np63-positive cells in caudal gut endoderm generated the stem/progenitor compartment of adult colorectal epithelium. The authors concluded from their study observations that "because p63 is a master regulator of stratified epithelial development, this finding provides a unique developmental insight into the cell of origin of squamous cell metaplasia and squamous cell carcinoma of the colon."]]> Isolation and Characterization http://moragabiotech.com/nucleus/index.php?itemid=1526 Mon, 6 May 2013 13:09:39 -0700 Identification of lncRNAs in Adult Neural Stem Cells and their Progeny In Vivo http://moragabiotech.com/nucleus/index.php?itemid=1519 Cell Stem Cell, A. D. Ramos et al. from the University of California, San Francisco reported their experimental results on the expression of long noncoding RNAs (lncRNAs) in adult mouse neural stem cells (NSCs). The investigators used complementary genome-wide techniques (RNA-seq, RNA CaptureSeq, and ChiP seq) for correlating the expression of lncRNAs with neural cell types derived from tissue isolates of the subventricular zone (SVZ). lncRNAs loci have unique chromatin signatures. From shRNA-mediated knockdown, the data revealed that Six3os and Dixfas were involved in the regulation of the glial-neuronal lineage specification of multipotent adult stem cells during neurogenesis.]]> Isolation and Characterization http://moragabiotech.com/nucleus/index.php?itemid=1519 Wed, 24 Apr 2013 08:19:00 -0700 CD24 and CD44 Mark Human Instestinal Epithelial Cell Populations with Characteristics of Active and Facultative Stem Cells http://moragabiotech.com/nucleus/index.php?itemid=1518 Stem Cells, A. D. Gracz et al. from the University of North Carolina at Chapel Hill reported their study findings on the isolation and characterization of a subpopulation of murine intestinal epithelial stem cells (iESCs). The investigators found that CD24 and CD44 are differentially expressed in both LGR5 positive (active) and HOPX positive (facultative) stem cells. With FACS analysis, the researchers were able to enrich for subpopulations of both LGR5 cells (CD24-/CD44+) and HOPX cells (Cd24+/CD44+). The authors concluded from their experimental results provide a method for isolating and studying intestinal stem cell subpopulations based upon cell surface signatures.]]> Isolation and Characterization http://moragabiotech.com/nucleus/index.php?itemid=1518 Tue, 23 Apr 2013 08:17:00 -0700 Molecular Hierarchy of Mammary Differentiation yields Refined Markers of Mammary Stem Cells http://moragabiotech.com/nucleus/index.php?itemid=1513 PNAS, C. O. dos Santos et al. from Cold Spring Harbor Laboratory (New York) reported their study results on identifying a new marker for mouse mammary gland stem cells (MaSCs). The investigators isolated and enriched subpopulation of MaSCs (Lin-CD24+CD29hiCD49rhi) labeled with a doxycycline-dependent H2b-GTP transgene. The study data demonstrated that H2b-GFPhi MaSCs reside within the mammary gland stem cell compartment. These slowly dividing cells had greater potential to reconstitute the stem cell niche than the unlabeled cells (H2b-GFPneg). The H2b-GFPhi MaSCs enriched population expressed the glycoprotein Cd1d which is also expressed on antigen-presenting cells. The researchers were able to identify a MaSC-enriched genes some of which control MsSC survival. The authors concluded that their data "provide tools for isolating a more precisely defined population of MaSCs and point to potentially critical factors for MaSC maintenance."]]> Isolation and Characterization http://moragabiotech.com/nucleus/index.php?itemid=1513 Wed, 17 Apr 2013 15:26:00 -0700 Extending Human Hematopoietic Stem Cell Survival In Vitro with Adipocytes http://moragabiotech.com/nucleus/index.php?itemid=1506 BioResearch Open Access, D. L. Gietting et al. from Tufts University reported their study results on culturing human hematopoietic stem cells (hHSCs) for extended periods of time using feeder cultures. The investigators conducted an array of experiments using different cell feeders to inhibit hHSC differentiation and prolong stem cell survival in vitro. Human mesenchymal stem cells (hMSCs) or either osteoblasts or adipocytes differentiated from hMSCs were used as feeder layers in cultures with minimal medium. The experimental data revealed that adipocytes as a feeder layer of cells showed the highest survival rate for CD34+ cells in vitro. Adipogenic feeder cells produced similar results. The researchers reported that direct cell-cell contact was necessary for producing the feeder layer's supportive effects. The experimental data revealed a direct correlation between the amount of adipocytes in the feeder layers and survival of the hHSCs. Thus, higher amounts of adipocytes exhibited less rapid decay of CD34+ cells. The authors concluded from their study results "that adipocytes assist in suppressing hHSC differentiation and aid in prolonging their survival in vitro.]]> Isolation and Characterization http://moragabiotech.com/nucleus/index.php?itemid=1506 Wed, 10 Apr 2013 17:24:00 -0700 Factors Affecting Successful Isolation of Human Corneal Endothelial Cells for Clinical Use http://moragabiotech.com/nucleus/index.php?itemid=1499 Cell Transplantation, J. S. Choi et al. from the University of Rochester Medical Center published their study results on the defining the factors leading to more efficient isolation and expansion of human corneal endolthelial cells (HCECs) for corneal transplantation. With endothelial keratoplasty, the investigators isolated HCECs from donors who varied in age and gender. HCECs were isolated and expanded by explant cultures or enzymatic digestion (collagenase II, dispase, or trypsin) of the Descemet's membrane. The cells were cultured in either collagen IV, fibronectin, or fibronectin-collagen coated plates. The experimental results revealed donor's age and HCECs isolation methods effected the characteristics of the cultured HCEC. Also, fibronectin-coated plates gave rise to "higher quality cultures." The authors concluded that their "results suggested that donor age and HCEC isolation methodology are the two factors that most directly affect the quality of the resulting HCEC culture in vitro."]]> Isolation and Characterization http://moragabiotech.com/nucleus/index.php?itemid=1499 Tue, 5 Mar 2013 21:17:00 -0700 Hematopoietic Stem Cell and Progenitor Cell Mechanisms in Myelodysplastic Syndromes http://moragabiotech.com/nucleus/index.php?itemid=1489 In the February 6th online early edition of PNAS, W. W. Pang et al. from Stanford University School of Medicine reported their study results demonstrating that hematopoietic stem cells (HSCs) are the disease-initiating cells giving rise to myelodyplastic syndrome (MDS). When the purified human HSCs from MDS samples were transplanted into immunodeficient mice, the investigators identified a recurrent loss of granulocyte-macrophage progenitors (GMPs) in bone marrow of low risk MDS patients which is distinguishable from clinical mimics. The study data suggested that loss of GMPs was likely attributed to apoptosis and increased phagocytosis (upregulation of calreticulin). Blocking calreticulin rescued low risk MDS myeloid progenitors from phagocytosis in vitro. HSCs from patients with high-risk refractory anemia with excess blasts (RAEB) stages of MDS, the population of GMP increased in frequency compared to normal concomitant with the myeloid progenitors evading phagocytosis as result of CD47 upregulation. The authors proposed that "MDS HSCs compete with normal HSCs in patients by increasing their frequency at the expense of normal hematopoiesis." Additionally, the investigators propose that upregulation of CD47 as a "don't eat me" signal is "an important transition step leading from low risk MDS to high risk and possibly, to acute myeloid leukemia."]]> Isolation and Characterization http://moragabiotech.com/nucleus/index.php?itemid=1489 Tue, 19 Feb 2013 21:15:00 -0700 Identification of CD44+ALDH+ Population Enriched for Epidermal Stem Cells with Long Term Repopulating Ability http://moragabiotech.com/nucleus/index.php?itemid=1480 Stem Cells, A. Z. Szabo et al. from the University of California, San Francisco reported their study results on isolation an enriched population of epidermal stem cells (EpiSCs). The investigators used freshly obtained human neonatal kertinocytes with the stem cell markers aldehyde dehydrogenase (ALDH) and CD44 as well as the integrins a6 and CD71. With flow cytometery, the researchers were able to isolate a subpopulation of ALDH+CD44+ and enrich 12.6 fold a long-term repopulating EpiSCs. The enriched long-term repopulating keratinocytes had the ability to self-renew, to express Bmi-1, to be serially transplanted, to form holoclone in vitro, and to exhibit multipotency in their ability to form hair follicle structures. Additionally, in vitro the ALDH+CD44+ cells were shown to have enhanced colony formation when cultured in either keratinocyte or embryonic stem cell growth media. The authors concluded from their study results that they are able "to quantify the relative number of EpiSCs in human keratinocyte populations using long-term repopulation as a functional test of stem cell nature."]]> Isolation and Characterization http://moragabiotech.com/nucleus/index.php?itemid=1480 Wed, 6 Feb 2013 10:43:00 -0700 Potential Role of Epigenetics on Multipotent Cell Differentiation Capacity of Mesenchymal Stromal Cells http://moragabiotech.com/nucleus/index.php?itemid=1429 Stem Cells, G. Yannarelli et al. from the University Health Network (Toronto, Canada) reported their study results on comparing the gene expression and methylation patterns of mesenchymal stem cells (MSCs) from the human umbilical cord perivascular cells (HUCPVCs) to those derived from the bone marrow (BM-MSCs). The investigators found that HUCPVCs had higher telomerase activity and longer telomeres compared to BM-MSCs. Additionally, the researchers reported higher expression levels for the pluripotency factors Oct4, Sox2, and Nanog in HUCPVCs compared to BM-MSCs. However, the difference in expression levels of these transcription factors was not associated with epigenetic changes since the methylation of patterns were similar for two types of MSCs. The scientists noted that methylation at these loci were greater than in embryonic stem cells, but less than in dermal fibroblasts. The authors concluded from their observations that the data suggest that" multipotentiality of MSCs is epigenetically restricted." The authors also noted that their "results are consistent with the notion that the MSC population (whether BM- or HUCPV-derived) exhibits higher proliferative capacity and contains more progenitor cells than do dermal fibroblasts."]]> Isolation and Characterization http://moragabiotech.com/nucleus/index.php?itemid=1429 Fri, 26 Oct 2012 22:40:00 -0700 Reconstitution of Mouse Spermatogonial Stem Cell Niches in Culture http://moragabiotech.com/nucleus/index.php?itemid=1418 Cell Stem Cell, M. Kanatsu-Shinohara et al. from Kyoto University School of Medicine (Japan) reported their study observations on defining the chemotactic factors in the stem cell niche within the seminiferous tubules of the mouse testis. Since spermatogonial stem cells (SSCs) reside in the seminferous tubules and migrate to them upon transplantation, the investigators established a testis feeder cell culture system to identify SSC chemotactic factors. In vitro testis cell coculture demonstrated that SSCs migrated beneath the Sertoli cells and formed cobblestone colonies. The experimental data also revealed that migration of SSCs and cobblestone formation were dependent upon GDNF (glial-derived neurotrophic factor) and CXCL12 in the cocultures. Additionally, GDNF was found to upregulate CXCL12 receptor expression. In vivo, SSC niche colonization requires the presence of CXCL12 and expression of its receptor, CXCR4.]]> Isolation and Characterization http://moragabiotech.com/nucleus/index.php?itemid=1418 Wed, 10 Oct 2012 16:36:00 -0700
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