Project description:Here, we assessed the expression of Mac-1 on mouse HSCs during regeneration following transplantation and observed a transient increase in Mac-1 expression during the early reconstitution phase. Serial transplantation experiments demonstrated that reconstitution potential was highly enriched in the Mac-1+ portion of the HSC pool.
Project description:Mouse hematopoietic stem cells (HSCs) have been extensively defined both molecularly and functionally at steady state, while regenerative stress induces immunophenotypical changes that limit high purity isolation and analysis. It is therefore important to identify markers that specifically label activated HSCs to gain further knowledge about their molecular and functional properties. Here, we assessed the expression of macrophage-1 antigen (MAC-1) on HSCs during regeneration following transplantation and observed a transient increase in MAC-1 expression during the early reconstitution phase. Serial transplantation experiments demonstrated that reconstitution potential was highly enriched in the MAC-1+ portion of the HSC pool. Moreover, in contrast to previous reports, we found that MAC-1 expression inversely correlates with cell cycling, and global transcriptome analysis showed that regenerating MAC-1+ HSCs share molecular features with stem cells with low mitotic history. Taken together, our results suggest that MAC-1 expression marks predominantly quiescent and functionally superior HSCs during early regeneration.
Project description:Hepatic stellate cells (HSC) constitute the most important fibrogenic cell type during liver fibrosis. To analyse the different phenotypes of quiescent and activated cells, cells of 5 animals were transdifferentiated in a well established in vitro transdifferentiaition assay and compared to freshly seeded, quiescent HSC. Gene expression profiling of quiescent and in vitro activated HSC revealed well known and new marker genes upregulated upon HSC activation. ltbp1 (latent transforming growth factor beta binding protein 1) is a crucial factor controlling the secretion and bioactivation of TGFß1. Using the data comparing quiescent and activated HSC, we were able to qualify the subtle but reproducible differences in gene expression observed when comparing activated ltbp1-deficient and activted wt HSC. ltbp1-deficient HSC showed a less fibrogenic phenotype after 6 days of in vitro transdifferentiation compared to the wt counterparts. The microarray data was indepently confirmed in vivo using an experimental model for the induction of liver fibrosis (ligation of the common bile duct). ltbp1-/- mice, after 4 weeks of bile obstruction, showed markedly reduced signs of liver fibrosis. Keywords: gene expression profiling, analysyis of a fibrogenic cell type in the liver and the influence of ltbp1-k.o.
Project description:Transcriptional profiling of primary cutaneous anaplastic large cell lymphoma cell line Mac-1 cells transduced with lenti-virus vector harboring shRNA against SATB1 gene comparing control untreated Mac-1 cells and Mac-1 cells transduced with scrambled shRNA, in which SATB1 expression is not affected. Two condition experiment, SATB1 silenced Mac-1 cells vs control Mac-1 cells. Biological replicates: 2 transduced replicates, 2 control replicates
Project description:In this study, we have employed MNase-Seq to reveal distinct nucleosome distribution patterns in morphologically and functionally differentiated MIC and MAC from asexually dividing Tetrahymena cells.
Project description:Transcriptional profiling of primary cutaneous anaplastic large cell lymphoma cell line Mac-1 cells transduced with lenti-virus vector harboring shRNA against SATB1 gene comparing control untreated Mac-1 cells and Mac-1 cells transduced with scrambled shRNA, in which SATB1 expression is not affected.
Project description:Liver fibrosis is a manifestation of chronic liver injury. It leads to hepatic dysfunction and is a critical element in the pathogenesis of cirrhosis and hepatocellular carcinoma. The activation of hepatic stellate cells (HSC) plays a central role in liver fibrogenesis of different etiologies. To elucidate the molecular mechanism of this phenomenon, it is important to analyze the changes in gene expression that accompany the HSC activation process. In this study, we isolated quiescent and activated HSCs from control mice and mice with CCl4-induced liver fibrosis, respectively, and performed RNA sequencing to compare the differences in gene expression patterns between the two types of HSCs.
Project description:Quiescent and dividing hemopoietic stem cells (HSC) display marked differences in their ability to move between the peripheral circulation and the bone marrow. Specifically, long-term engraftment potential predominantly resides in the quiescent HSC subfraction, and G-CSF mobilization results in the preferential accumulation of quiescent HSC in the periphery. In contrast, stem cells from chronic myeloid leukemia (CML) patients display a constitutive presence in the circulation. To understand the molecular basis for this, we have used microarray technology to analyze the transcriptional differences between dividing and quiescent, normal, and CML-derived CD34+ cells.
Project description:Under conditions of the liver exposed to chronic insults such as viral infection, excess deposition of fat, regurgitation of bile acids etc., hepatic stellate cells (HSCs) change from quiescent to activated states and proliferate. During this process, HSCs secrete collagen and metalloproteinases. Involvement of collagen in sustaining activated HSC (aHSC) survival was postulated, although the precise mechanisms underlying the survival and apoptosis of aHSCs is still controversial. In this study, we compared the expression profiles between quiescent and activated HSCs to clarify the mechanisms of apoptosis for exploration of novel anti-fibrosis modalities.
Project description:Hierarchically organized tissues, such as hematopoietic systems, muscle, or skin harbor deeply quiescent stem cells which start proliferating in response to external insults. In contrast, it remains obscure whether similar quiescent cells exist in epithelia of digestive organs. Here we identified a deeply quiescent population in gastric corpus but not in other gastrointestinal organs after systematic examination of H2b-GFP label-retaining cells. The label-retaining cells in corpus epithelia belonged to a subpopulation of chief cells that were located near basal layers of corpus and did not overlap with Troyhigh, Lgr5high, or Misthigh cell population. The identified quiescent cells were marked with activation of Atf4 and unfolded protein response. External damages by indomethacin treatment triggered proliferation of the quiescent populations, indicating that chief cells of gastric corpus harbor deeply quiescent reserve cells with high levels of internal stress response activity.