Project description:The molecular identification of adult hepatic stem/progenitor cells has been hampered by the lack of truly specific markers. To isolate putative adult liver progenitor cells, we used cell surface-marking antibodies, including MIC1-1C3, to isolate subpopulations of liver cells from normal adult mice or those undergoing an oval cell response and tested their capacity to form bilineage colonies in vitro. Robust clonogenic activity was found to be restricted to a subset of biliary duct cells antigenically defined as CD45(-)/CD11b(-)/CD31(-)/MIC1-1C3(+)/CD133(+)/CD26(-), at a frequency of one of 34 or one of 25 in normal or oval cell injury livers, respectively. Gene expression analyses revealed that Sox9 was expressed exclusively in this subpopulation of normal liver cells and was highly enriched relative to other cell fractions in injured livers. In vivo lineage tracing using Sox9creER(T2)-R26R(YFP) mice revealed that the cells that proliferate during progenitor-driven liver regeneration are progeny of Sox9-expressing precursors. A comprehensive array-based comparison of gene expression in progenitor-enriched and progenitor-depleted cells from both normal and DDC (3,5-diethoxycarbonyl-1,4-dihydrocollidine or diethyl1,4-dihydro-2,4,6-trimethyl-3,5-pyridinedicarboxylate)-treated livers revealed new potential regulators of liver progenitors.
Project description:The molecular identification of adult hepatic stem/progenitor cells has been hampered by the lack of truly specific markers. To isolate putative adult liver progenitor cells, we used cell surface-marking antibodies, including MIC1-1C3, to isolate subpopulations of liver cells from normal adult mice or those undergoing an oval cell response and tested their capacity to form bilineage colonies in vitro. Robust clonogenic activity was found to be restricted to a subset of biliary duct cells antigenically defined as CD45–/CD11b–/CD31–/MIC1-1C3+/CD133+/CD26–, at a frequency of one of 34 or one of 25 in normal or oval cell injury livers, respectively. Gene expression analyses revealed that Sox9 was expressed exclusively in this subpopulation of normal liver cells and was highly enriched relative to other cell fractions in injured livers. In vivo lineage tracing using Sox9creERT2-R26RYFP mice revealed that the cells that proliferate during progenitor-driven liver regeneration are progeny of Sox9-expressing precursors. A comprehensive array-based comparison of gene expression in progenitor-enriched and progenitor-depleted cells from both normal and DDC (3,5-diethoxycarbonyl-1,4-dihydrocollidine or diethyl1,4-dihydro-2,4,6-trimethyl- 3,5-pyridinedicarboxylate)-treated livers revealed new potential regulators of liver progenitors.
Project description:The molecular identification of adult hepatic stem/progenitor cells has been hampered by the lack of truly specific markers. To isolate putative adult liver progenitor cells, we used cell surface-marking antibodies, including MIC1-1C3, to isolate subpopulations of liver cells from normal adult mice or those undergoing an oval cell response and tested their capacity to form bilineage colonies in vitro. Robust clonogenic activity was found to be restricted to a subset of biliary duct cells antigenically defined as CD45–/CD11b–/CD31–/MIC1-1C3+/CD133+/CD26–, at a frequency of one of 34 or one of 25 in normal or oval cell injury livers, respectively. Gene expression analyses revealed that Sox9 was expressed exclusively in this subpopulation of normal liver cells and was highly enriched relative to other cell fractions in injured livers. In vivo lineage tracing using Sox9creERT2-R26RYFP mice revealed that the cells that proliferate during progenitor-driven liver regeneration are progeny of Sox9-expressing precursors. A comprehensive array-based comparison of gene expression in progenitor-enriched and progenitor-depleted cells from both normal and DDC (3,5-diethoxycarbonyl-1,4-dihydrocollidine or diethyl1,4-dihydro-2,4,6-trimethyl- 3,5-pyridinedicarboxylate)-treated livers revealed new potential regulators of liver progenitors. Treated and untreated cells were sorted by cell surface markers then compared. M+/133+ untreated: 4 biological and 1 technical replicate - total of 5 M-/133- untreated: 2 biological and 1 technical replicate - total of 3 M+/133+ DDC-treated: 4 biological replicates - total of 4 M-/133- DDC-treated: 4 biological replicates - total of 4
Project description:Here, we have prospectively isolated and characterized, for the first time, clonogenic cells with self-renewal capacities from mantle cell lymphoma (MCL), a particularly deadly form of non-Hodgkin's lymphoma (NHL). Self-renewal and tumorigenic activities were enriched in MCL cell fractions that lacked expression of the prototypic B-cell surface marker, CD19. CD45+CD19- cells represented a relatively small fraction of the total MCL tumor cells; however, they recapitulated the heterogeneity of original patient tumors on transplantation into immunodeficient mice. As few as 100 of these cells displayed self-renewal capacities in secondary and tertiary recipient mice by in vivo limiting dilution assays. Similar to leukemic stem cells, CD45+CD19- MCL cells also displayed a quiescent status as determined by dye efflux assays. In summary, this study is the first to isolate subpopulations of MCL cells that have self-renewal and tumorigenic capacities. Identification and characterization of MCL-ICs are important first steps toward understanding how self-renewal and tumorigenicity are regulated in MCL and designing targeted therapies against MCL-ICs will ultimately lead to improved outcomes for MCL patients.
Project description:The ability to purify to homogeneity a population of hepatic progenitor cells from adult liver is critical for their characterization prior to any therapeutic application. As a step in this direction, we have used a bipotential liver cell line from 14 days postcoitum mouse embryonic liver to compile a list of cell surface markers expressed specifically by liver progenitor cells. These cells, known as bipotential mouse embryonic liver (BMEL) cells, proliferate in an undifferentiated state and are capable of differentiating into hepatocyte-like and cholangiocyte-like cells in vitro. Upon transplantation, BMEL cells are capable of differentiating into hepatocytes and cholangiocytes in vivo. Microarray and Gene Ontology (GO) analysis of gene expression in the 9A1 and 14B3 BMEL cell lines grown under proliferating and differentiating conditions was used to identify cell surface markers preferentially expressed in the bipotential undifferentiated state. This analysis revealed that proliferating BMEL cells express many genes involved in cell cycle regulation, whereas differentiation of BMEL cells by cell aggregation causes a switch in gene expression to functions characteristic of mature hepatocytes. In addition, microarray data and protein analysis indicated that the Notch signaling pathway could be involved in maintaining BMEL cells in an undifferentiated stem cell state. Using GO annotation, a list of cell surface markers preferentially expressed on undifferentiated BMEL cells was generated. One marker, Cd24a, is specifically expressed on progenitor oval cells in livers of diethyl 1,4-dihydro-2,4,6-trimethyl-3,5-pyridinedicarboxylate-treated animals. We therefore consider Cd24a expression a candidate molecule for purification of hepatic progenitor cells. Disclosure of potential conflicts of interest is found at the end of this article.
Project description:Cardiac progenitor/stem cells in adult hearts represent an attractive therapeutic target for heart regeneration, though (inter)-relationships among reported cells remain obscure. Using single-cell qRT-PCR and clonal analyses, here we define four subpopulations of cardiac progenitor/stem cells in adult mouse myocardium all sharing stem cell antigen-1 (Sca1), based on side population (SP) phenotype, PECAM-1 (CD31) and platelet-derived growth factor receptor-α (PDGFRα) expression. SP status predicts clonogenicity and cardiogenic gene expression (Gata4/6, Hand2 and Tbx5/20), properties segregating more specifically to PDGFRα(+) cells. Clonal progeny of single Sca1(+) SP cells show cardiomyocyte, endothelial and smooth muscle lineage potential after cardiac grafting, augmenting cardiac function although durable engraftment is rare. PDGFRα(-) cells are characterized by Kdr/Flk1, Cdh5, CD31 and lack of clonogenicity. PDGFRα(+)/CD31(-) cells derive from cells formerly expressing Mesp1, Nkx2-5, Isl1, Gata5 and Wt1, distinct from PDGFRα(-)/CD31(+) cells (Gata5 low; Flk1 and Tie2 high). Thus, PDGFRα demarcates the clonogenic cardiogenic Sca1(+) stem/progenitor cell.
Project description:UnlabelledThe liver contains a population of small bipotential facultative progenitor cells that reconstitute liver function when mature hepatocytes or cholangiocytes are unable to proliferate. Mesenchymal markers, including members of the forkhead transcription factor gene family, have been detected in hepatic progenitor cells. The winged helix transcription factor Foxl1 localizes to mesenchymal cells in the intestine; however, its expression in the liver has not been reported. We found that Foxl1 is expressed in rare cells in the normal liver but is dramatically induced in the livers of mice that have undergone bile duct ligation or were fed a 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC)-containing or choline-deficient, ethionine-supplemented diet. In addition, we employed genetic lineage tracing using a Foxl1-Cre transgenic mouse crossed with the Rosa26R lacZ reporter line to demonstrate that Foxl1-Cre-expressing cells are present within the periportal region shortly after injury. These cells give rise to both hepatocytes [marked by hepatocyte nuclear factor 4 alpha (HNF-4alpha) expression] and cholangiocytes (marked by CK19 expression), indicating that these cells are derived from Foxl1-Cre-expressing cells. Foxl1-Cre-expressing cells are distinct from hepatic stellate cells, portal fibroblasts, and myofibroblasts, although they are located in close proximity to portal fibroblasts. These results demonstrate that the early Foxl1-Cre lineage cell gives rise to both cholangiocytes and hepatocytes after liver injury and suggest the potential for progenitor-portal fibroblast cell interactions.ConclusionWe propose that Foxl1 is a bona fide marker of the facultative progenitor cell in the mouse liver.
Project description:Adult liver progenitor cells are biliary-like epithelial cells that emerge only under injury conditions in the periportal region of the liver. They exhibit phenotypes of both hepatocytes and bile ducts. However, their origin and their significance to injury repair remain unclear. Here, we used a chimeric lineage tracing system to demonstrate that hepatocytes contribute to the progenitor pool. RNA-sequencing, ultrastructural analysis, and in vitro progenitor assays revealed that hepatocyte-derived progenitors were distinct from their biliary-derived counterparts. In vivo lineage tracing and serial transplantation assays showed that hepatocyte-derived proliferative ducts retained a memory of their origin and differentiated back into hepatocytes upon cessation of injury. Similarly, human hepatocytes in chimeric mice also gave rise to biliary progenitors in vivo. We conclude that human and mouse hepatocytes can undergo reversible ductal metaplasia in response to injury, expand as ducts, and subsequently contribute to restoration of the hepatocyte mass.
Project description:BackgroundClinical trials in ischemic patients showed the safety and benefit of autologous bone marrow progenitor cell transplantation. Non-bone marrow progenitor cells with proangiogenic capacities have been described, yet they remain clinically unexploited owing to their scarcity, difficulty of access, and low ex vivo expansibility. We investigated the presence, antigenic profile, expansion capacity, and proangiogenic potential of progenitor cells from the saphenous vein of patients undergoing coronary artery bypass surgery.Methods and resultsCD34-positive cells, negative for the endothelial marker von Willebrand factor, were localized around adventitial vasa vasorum. After dissection of the vein from surrounding tissues and enzymatic digestion, CD34-positive/CD31-negative cells were isolated by selective culture, immunomagnetic beads, or fluorescence-assisted cell sorting. In the presence of serum, CD34-positive/CD31-negative cells gave rise to a highly proliferative population that expressed pericyte/mesenchymal antigens together with the stem cell marker Sox2 and showed clonogenic and multilineage differentiation capacities. We called this population "saphenous vein-derived progenitor cells" (SVPs). In culture, SVPs integrated into networks formed by endothelial cells and supported angiogenesis through paracrine mechanisms. Reciprocally, endothelial cell-released factors facilitated SVP migration. These interactive responses were inhibited by Tie-2 or platelet-derived growth factor-BB blockade. Intramuscular injection of SVPs in ischemic limbs of immunodeficient mice improved neovascularization and blood flow recovery. At 14 days after transplantation, proliferating SVPs were still detectable in the recipient muscles, where they established N-cadherin-mediated physical contact with the capillary endothelium.ConclusionsSVPs generated from human vein CD34-positive/CD31-negative progenitor cells might represent a new therapeutic tool for angiogenic therapy in ischemic patients.