bluuebunny/crossref_metadata_2025_split huggingface dataset:
Transmigration of CD34+ Cells Across Specialized and Nonspecialized Endothelium Requires Prior Activation by Growth Factors and Is Mediated by PECAM-1 (CD31)
Authors: Yong Kwee L. , Watts Mike , Shaun Thomas N. , Sullivan Angela , Ings Stuart , Linch David C. 
Published: October 2019

AbstractThe transmigration of hematopoietic progenitor cells (HPCs) across vascular endothelium is a critical step in the homing of transplanted stem cells, but the molecular basis for this is unknown. We used mobilized peripheral blood CD34+ selected cells and cultured bone marrow microvascular (BMECs) and human umbilical vein endothelial cells (HUVECs) to investigate the adhesion and transendothelial migration of HPCs. Colony-forming cells (CFCs) in freshly isolated CD34+ cells showed high levels of adhesion to both forms of endothelium (28% ± 4% and 38% ± 6% of granulocyte-macrophage colony-forming cells [GM-CFCs] adhering to HUVECs and BMECs, respectively), but were unable to migrate to any significant extent across either (1.0% ± 0.3% and 1.1% ± 0.6% of GM-CFCs migrating across HUVECs and BMECs, respectively). Greater than 95% of peripheral blood CD34+ cells are in G0/G1 of the cell cycle, but after 48 to 72 hours of stimulation with growth factors (interleukin-3 [IL-3] 12 ng/mL, stem cell factor 10 ng/mL, and IL-6 10 ng/mL), 28% ± 5% of cells were in S+G2/M. Growth factor stimulation had no effect on the adhesion of mobilized CFCs but resulted in enhanced migration of these cells (9.8% ± 1.6% and 12.6% ± 3.1% of GM-CFCs migrating across HUVECs and BMECs, respectively; P < .01, n = 6). Assessment of cell proliferation by the3H-thymidine suicide method showed that, whereas 11.7% ± 3.3% of proliferating CFCs transmigrated across endothelium, only 1.3% ± 0.3% of nonproliferating CFCs did so (P < .05, n = 5). Transmigration of growth factor-activated CFCs was inhibited by anti-CD18 monoclonal antibody (MoAb; 50% ± 18% inhibition) and by anti–platelet endothelial cell adhesion molecule-1 (PECAM-1) MoAb (70.8% ± 7.1% inhibition; P < .05, n = 3). IL-1 stimulation of HUVECs had no significant effect on CD34+cell transmigration, but caused marked enhancement of neutrophil migration. Stem cell homing may depend, in part, on the ability of local cytokines to upregulate the transmigratory ability of these cells. The transmigration of HPCs shares at least some molecular pathways with that of mature cells (CD18 and PECAM-1), but is differently affected by endothelial activation.
Stage-Specific Expression of Polycomb Group Genes in Human Bone Marrow Cells
Authors: Lessard Julie , Baban Soheyl , Sauvageau Guy 
Published: October 2019

AbstractMammalian Polycomb group (Pc-G) genes, constituting some 5 subfamilies based on their identity to the Drosophila genesPc, Psc, ph, esc, and E(z), appear to play critical roles in maintaining the transcriptional repression state ofHox/HOM-C genes during development. Despite increasing evidence of the important role of Hox genes in both normal hematopoiesis and leukemic transformation, little is known about the expression and possible function played by Pc-G genes in hematopoietic cells. To address this, we first examined the expression of Pc genes in purified CD34+ human bone marrow cells by reverse transcriptase-polymerase chain reaction (RT-PCR), using degenerate primers that specifically amplify the majority of Pcgenes. This analysis showed the expression of 8 different Pcgenes in CD34+ bone marrow cells, includingHP1Hsα, HP1Hsγ, the heterochromatin p25 protein, the human homologue of the murine M32 gene, and 4 novel members of this family. To assess whether Pc-G mRNA levels change during differentiation of bone marrow cells, a quantitative RT-PCR method was used to amplify the total cDNA originating from three purified subpopulations of CD34+bone marrow cells known to differ in their ability to grow in long-term or semisolid cultures. In sharp contrast to Hox gene expression, which is highest in the most primitive bone marrow cells, these studies show that the expression level of 8 of the 9 Pc-Ggenes studied (ie, HP1Hsα, HP1Hsγ, M31, M32, M33, Mel-18, Mph1/Rae-28, and ENX-1) markedly increases with differentiation of bone marrow cells. Interestingly,BMI-1 exhibits a strikingly different pattern of expression, with high expression levels in primitive cells and very little expression in mature CD34− cells. Together, these results document for the first time that differentiation of human bone marrow cells is accompanied by profound changes in Pc-G gene expression levels.
Fas Ligand Is Present in Human Erythroid Colony-Forming Cells and Interacts With Fas Induced by Interferon γ to Produce Erythroid Cell Apoptosis
Authors: Dai Chun-Hua , Price James O. , Brunner Thomas , Krantz Sanford B. 
Published: October 2019

AbstractInterferon γ (IFNγ) inhibits the growth and differentiation of highly purified human erythroid colony-forming cells (ECFCs) and induces erythroblast apoptosis. These effects are dose- and time-dependent. Because the cell surface receptor known as Fas (APO-1; CD95) triggers programmed cell death after activation by its ligand and because incubation of human ECFCs with IFNγ produces apoptosis, we have investigated the expression and function of Fas and Fas ligand (FasL) in highly purified human ECFCs before and after incubation with IFNγ in vitro. Only a small percentage of normal human ECFCs express Fas and this is present at a low level as detected by Northern blotting for the Fas mRNA and flow cytometric analysis of Fas protein using a specific mouse monoclonal antibody. The addition of IFNγ markedly increased the percentage of cells expressing Fas on the surface of the ECFCs as well as the intensity of Fas expression. Fas mRNA was increased by 6 hours, whereas Fas antigen on the cell surface increased by 24 hours, with a plateau at 72 hours. This increase correlated with the inhibitory effect of IFNγ on ECFC proliferation. CH-11 anti-Fas antibody, which mimics the action of the natural FasL, greatly enhanced IFNγ-mediated suppression of cell growth and production of apoptosis, indicating that Fas is functional. Expression of FasL was also demonstrated in normal ECFCs by reverse transcriptase-polymerase chain reaction and flow cytometric analysis with specific monoclonal antibody. FasL was constitutively expressed among erythroid progenitors as they matured from day 5 to day 8 and IFNγ treatment did not change this expression. Apoptosis induced by IFNγ was greatly reduced by the NOK-2 antihuman FasL antibody and an engineered soluble FasL receptor, Fas-Fc, suggesting that Fas-FasL interactions among the ECFCs produce the erythroid inhibitory effects and apoptosis initiated by IFNγ.
Engraftment and Retroviral Marking of CD34+ and CD34+CD38− Human Hematopoietic Progenitors Assessed in Immune-Deficient Mice
Authors: Dao Mo A. , Shah Ami J. , Crooks Gay M. , Nolta Jan A. 
Published: October 2019

AbstractRetroviral-mediated transduction of human hematopoietic stem cells to provide a lifelong supply of corrected progeny remains the most daunting challenge to the success of human gene therapy. The paucity of assays to examine transduction of pluripotent human stem cells hampers progress toward this goal. By using the beige/nude/xid (bnx)/hu immune-deficient mouse xenograft system, we compared the transduction and engraftment of human CD34+progenitors with that of a more primitive and quiescent subpopulation, the CD34+CD38− cells. Comparable extents of human engraftment and lineage development were obtained from 5 × 105 CD34+ cells and 2,000 CD34+CD38− cells. Retroviral marking of long-lived progenitors from the CD34+ populations was readily accomplished, but CD34+CD38− cells capable of reconstituting bnx mice were resistant to transduction. Extending the duration of transduction from 3 to 7 days resulted in low levels of transduction of CD34+CD38− cells. Flt3 ligand was required during the 7-day ex vivo culture to maintain the ability of the cells to sustain long-term engraftment and hematopoiesis in the mice.
Isolation and Characterization of Murine Clonogenic Osteoclast Progenitors by Cell Surface Phenotype Analysis
Authors: Muguruma Yukari , Lee Minako Y. 
Published: October 2019

Abstract
Osteoclasts are bone resorbing cells of hematopoietic origin; however, a progenitor cell population that gives rise to mature osteoclasts remains elusive. We have characterized a unique cell surface phenotype of clonogenic osteoclast progenitors (colony-forming unit–osteoclast [CFU-O]) and obtained a marrow cell population selectively enriched for these progenitors. Whole bone marrow cells were sequentially separated based on physical and cell surface characteristics, and the presence of CFU-O and other hematopoietic progenitors was examined. CFU-O was enriched in a nonadherent, low-density, lineage-marker–negative (Lin−), Thy1.2-negative (Thy1.2−), Sca1-negative (Sca1−), and c-kit–positive (c-kit+) population, as were the progenitors that were responsive to macrophage–colony-stimulating factor(CSF; CFU-M), granulocyte-macrophage-CSF (CFU-GM), and stem cell factor (CFU-SCF). When the Lin−Thy1.2−Sca1−population was divided into c-kithigh and c-kitlow populations based on c-kit fluorescence, over 88% of CFU-M, CFU-GM, and CFU-SCF were found in the c-kithighpopulation. In relation to the above mentioned hematopoietic progenitors, CFU-O was significantly higher in the c-kitlowpopulation: 80% of progenitors present in the c-kitlowpopulation were CFU-O. The CFU-O in both c-kithigh and c-kitlow populations showed key features of the osteoclast: multinucleated tartrate-resistant acid phosphatase–positive cell formation, expressions of vitronectin receptors, c-src and calcitonin receptors, and bone resorption. We have identified a progenitor cell population in the earliest stage of the osteoclast lineage so far described and developed a method to isolate it from other hematopoietic progenitors. This should help pave the way to understand the molecular mechanisms of osteoclast differentiation.
No Neuronal Regulation of Murine Bone Marrow Function
Authors: Benestad Haakon B. , Strøm-Gundersen Inger , Ole Iversen Per , Haug Egil , Njå Arild 
Published: October 2019

AbstractBone marrow is innervated by efferent (sympathetic) and afferent nerves, but it is not clear whether these nerves affect cell formation or release in any significant way. To elucidate this problem, we studied mice neonatally sympathectomized with 6-hydroxydopamine and adult mice in which one hind limb was surgically denervated. Progenitor and transit cell numbers and proliferative activity were estimated in bone marrow, blood, and spleen. In addition, we performed unilateral electrical stimulation of nerve fibers to tibial marrow and applied a cell mobilizing stimulus (bleeding, granulocyte colony-stimulating factor injection, or intraperitoneal injection of a chemotactic substance) to investigate cell egress from the marrow. Blood flow to hindleg bone marrow was assessed with the radioactive microsphere technique. Except for a smaller bone marrow cell population and lower body weight in neonatally sympathectomized mice, we found no clear indications that bone marrow innervation influenced cell production. Also, the innervation did not detectably affect cell release from the marrow. Electrical stimulation of hind limb nerves did not change the blood flow to the marrow, whereas it markedly decreased blood flow to the overlying muscle. We therefore conclude that no obvious function can be ascribed to tibial marrow innervation in the mouse.
Correlation of Thrombosis With Increased Platelet Turnover in Thrombocytosis
Authors: Rinder Henry M. , Schuster Judith E. , Rinder Christine S. , Wang Chao , Schweidler Helen J. , Smith Brian R. 
Published: October 2019

Abstract
There are no readily applicable methods to routinely assess thrombosis risk and treatment response in thrombocytosis. Reticulated platelets (RP) define the most recently released platelets in the circulation, and the RP% has been shown to estimate platelet turnover in thrombocytopenic states. We examined whether increased RP values were associated with thrombotic complications in thrombocytosis. Platelet count, RP%, and absolute RP count were measured at presentation in 83 patients with chronic or transient thrombocytosis, 46 patients with deep vein (DVT) or arterial (ART) thrombosis and normal platelet counts, and 83 healthy controls with normal platelet counts. Chronic thrombocytosis patients presenting with thrombosis (n = 14) had significantly higher RP% (14.7% ± 10.1%, mean ± SD) than asymptomatic chronic thrombocytosis patients (n = 23, RP% = 3.4% ± 1.8%), healthy controls (3.4% ± 1.3%), DVT patients (n = 21, 3.8% ± 2.1%), or ART patients (n = 25, 4.5% ± 4.1%, P < .05 for all comparisons). Chronic thrombocytosis patients with thrombosis also had significantly higher absolute RP counts than asymptomatic chronic thrombocytosis patients (98 ± 64 × 109/L [range, 54 to 249 × 109/L] v 30 ± 13 × 109/L [range, 11 to 51 × 109/L]; P = .0004), whereas healthy controls, DVT, and ART patients had similarly low absolute RP counts (6 ± 6 × 109/L, 9 ± 7 × 109/L, and 11 ± 7 × 109/L, respectively; P > .49). The RP% and absolute RP counts remained significantly higher in chronic thrombocytosis patients with thrombosis when patients were further subdivided into primary myeloproliferative disorders versus secondary thrombocytosis. Similarly elevated RP percentages and absolute counts were also noted in transient thrombocytosis patients with thrombosis (n = 6, 11.5% ± 4.4% and 90 ± 46 × 109/L, respectively) when compared with asymptomatic transient thrombocytosis patients (n = 40, 4.5% ± 2.7% and 35 ± 16 × 109/L, respectively) and to all control groups (P < .05 for all comparisons). In addition, 7 of 8 thrombocytosis patients who were studied before developing symptoms of thrombosis had elevated absolute RP counts compared with only 1 of 63 thrombocytosis patients who remained asymptomatic. Follow-up studies in seven chronic thrombocytosis patients showed that successful aspirin treatment of symptomatic recurrent thrombosis significantly reduced the RP% from 17.1% ± 10.9% before therapy to 4.8% ± 2.0% after therapy; absolute RP counts decreased from 102 ± 67 × 109/L to 26 ± 10 × 109/L (P < .01 for both). We conclude that thrombosis in the setting of an elevated platelet count is associated with increased platelet turnover, which is reversed by aspirin therapy. Measurement of reticulated platelets to assess platelet turnover may be useful in evaluating both treatment response and thrombotic risk in thrombocytosis.
Studies of Multimerin in Human Endothelial Cells
Authors: Hayward Catherine P. M. , Cramer Elisabeth M. , Song Zhili , Zheng Shilun , Fung Roxanna , Massé Jean-Marc , Stead Ron H. , Podor Thomas J. 
Published: October 2019

AbstractMultimerin is a novel, massive, soluble protein that resembles von Willebrand factor in its repeating, homomultimeric structure. Both proteins are expressed by megakaryocytes and endothelial cells and are stored in the region of platelet α-granules resembling Weibel-Palade bodies. These findings led us to study the distribution of multimerin within human endothelial cells. Multimerin was identified in vascular endothelium in situ. In cultured endothelial cells, multimerin was identified within round to rod-shaped, dense-core granules, some of which contained intragranular, longitudinally arranged tubules and resembled Weibel-Palade bodies. However, multimerin was found primarily in different structures than the Weibel-Palade body proteins von Willebrand factor and P-selectin. After stimulation with secretagogues, multimerin was observed to redistribute from intracellular structures to the external cellular membrane, without detectable accompanied secretion of multimerin into the culture media. In early passage endothelial cell cultures, multimerin was associated with extensive, fibrillary, extracellular matrix structures, in a different distribution than fibronectin. Although multimerin and von Willebrand factor are stored together in platelets, they are mainly found within different structures in endothelial cells, indicating that there are tissue-specific differences in the sorting of these soluble, multimeric proteins.
Platelet-Endothelial Interactions in Inflamed Mesenteric Venules
Authors: Frenette Paul S. , Moyna Caitlin , Hartwell Daqing W. , Lowe John B. , Hynes Richard O. , Wagner Denisa D. 
Published: October 2019

AbstractThe selectins are membrane glycoproteins promoting adhesive events between leukocytes, platelets, and endothelial cells. We have previously demonstrated that platelets roll on P-selectin expressed on stimulated endothelium. In this study, we wished to examine the function of both the platelet and endothelial selectins, P- and E-selectins, in mediating platelet-endothelial interactions during inflammation. We demonstrate, using intravital microscopic examination of venules inflamed with tumor necrosis factor-α (TNF-α), that resting platelets interact with both P- and E-selectins and that the leukocyte α(1,3)fucosyltransferases FucT IV and FucT VII do not provide platelets with selectin ligand activity. We also show that after thrombin activation of wild-type (+/+) platelets, platelet P-selectin can mediate interactions on a TNF-α–inducible endothelial ligand. To evaluate the potential role of platelet P-selectin in the recruitment of leukocytes to inflammatory sites, we reconstituted the bone marrow of mice deficient in both P- and E-selectins (P/E−/−) with wild-type (+/+) or P-selectin–deficient (P−/−) bone marrow containing megakaryocytic precursors. Providing +/+ platelets to P/E−/− mice by bone marrow transplantation did not rescue the immunodeficient phenotype, suggesting that platelet P-selectin does not have an active function in the recruitment of leukocytes into inflammatory sites. To participate in inflammatory or hemostatic responses, platelets may use the endothelial selectins.
Characterization of Functional Vanilloid Receptors Expressed by Mast Cells
Authors: Bı́ró Tamás , Maurer Marcus , Modarres Shayan , Lewin Nancy E. , Brodie Chaya , Ács Géza , Ács Péter , Paus Ralf , Blumberg Peter M. 
Published: October 2019

AbstractCapsaicin and its ultrapotent analog resiniferatoxin (RTX) act through specific vanilloid receptors on sensory neurons. The C-type receptor is coupled to 45Ca uptake, whereas the R-type is detectable by [3H]RTX binding. We describe here specific vanilloid responses in murine mast cells (MCs). In the MC lines and in bone marrow-derived mast cells, capsaicin and RTX induced45Ca uptake similarly to that observed for cultured rat dorsal root ganglion neurons (DRGs). This response was antagonized by the antagonists capsazepine and ruthenium red. As in DRGs, pretreatment of MCs with capsaicin or RTX induced desensitization to subsequent stimulation of 45Ca uptake. The potency for desensitization by RTX in the MCs corresponded to that for 45Ca uptake, whereas in DRGs it occurred at significantly lower concentrations corresponding to that for the high-affinity [3H]RTX binding site. Consistent with this difference, in MCs we were unable to detect [3H]RTX binding. Vanilloids were noncytotoxic to the MCs, in contrast to the DRGs. Although vanilloids did not cause degranulation in MCs, in the P815 clone capsaicin evoked selective interleukin-4 release. We conclude that certain MCs possess vanilloid receptors, but only the C-type that functions as a channel. Our finding that MCs can respond directly to capsaicin necessitates a reevaluation of the in vivo pathway of inflammation in response to vanilloids.
Increased Mucosal B-Lymphocyte Apoptosis During Polymicrobial Sepsis Is a Fas Ligand But Not an Endotoxin-Mediated Process
Authors: Ayala Alfred , Xin Xu Ying , Ayala Carol A. , Sonefeld Diane E. , Karr Shannon M. , Evans Tracy A. , Chaudry Irshad H. 
Published: October 2019

AbstractSepsis is reported to induce an increase in the rate of apoptosis (Ao), in immature lymphoid cells residing in hematopoietic tissues such as the thymus and bone marrow. Alternatively, secondary lymphoid tissue, such as the spleen exhibit little innate (unstimulated) Ao. However, it is unknown whether or not polymicrobial sepsis has any effects on the frequency of Aoin mucosal lymphoid tissue and what, if any, are the functional consequences of such a change. To assess this, Peyer's patch cells were harvested from C3H/HeN (endotoxin-sensitive) mice killed 12 or 24 hours after the onset of polymicrobial sepsis (cecal ligation and puncture [CLP]). The results indicate that the percentage of cells that were Ao+ as determined by flow cytometry were markedly increased at 24 hours, but not at 12 hours post-CLP. This correlates well with evidence of increased DNA fragmentation as well as histological changes observed both at a light and transmission electron microscopic level of the Peyer's patch Ao. Phenotypically, these changes were restricted to the B220+ (B-cell) population that also exhibited a marked increase of Fas/Apo-1 antigen expression. The functional consequence of this increased apoptosis appears to be associated with the endogenous stimulation (activation) of IgA production by mucosal B lymphocytes and increased nuclear c-Rel expression. Furthermore, we found that Peyer's patch lymphocytes isolated from C3H/HeJ-Faslgld(endotoxin-tolerant/Fas ligand- [FasL] deficient) as opposed to C3H/HeJ (endotoxin-tolerant) inbred mice did not exhibit increased Ao after CLP. These findings indicate that increased B-cell Ao appears to be a FasL-Fas antigen-mediated process, but is not due to endotoxin sensitivity. In conclusion, we speculate that the increased Fas-associated apoptosis detected in mucosal B cells (as opposed to splenic or bone marrow B cells) may be due to increased luminal antigens other than endotoxin, released due to gut barrier integrity breakdown during sepsis.
Detailed Molecular Delineation of 13q14.3 Loss in B-Cell Chronic Lymphocytic Leukemia
Authors: Corcoran Martin M. , Rasool Omid , Liu Yie , Iyengar Arati , Grander Dan , Ibbotson Rachel E. , Merup Mats , Wu Xiushan , Brodyansky Vadim , Gardiner Anne C. , Juliusson Gunnar , Chapman Robert M. , Ivanova Ganka , Tiller Mary , Gahrton Gosta , Yankovsky Nick , Zabarovsky Eugene , Oscier David G. , Einhorn Stefan 
Published: October 2019

Abstract
A region of chromosome 13q14.3, telomeric to the Retinoblastoma gene RB-1 is frequently deleted in patients with B-cell chronic lymphocytic leukemia (B-CLL). A cosmid and P1-derived artificial chromosome (PAC) contig spanning over 600 kb has been constructed, which encompasses this locus. The contig clones have been used to order a number of markers along the minimally deleted region and to localize a series of CpG islands corresponding to possible candidate genes. A novel polymorphic dinucleotide repeat, 6E3.2, present in one of the ordered cosmid clones has been isolated for use in deletion mapping studies of patient DNA. Leukemic samples from 229 CLL patients have been screened for loss of heterozygosity using microsatellite markers and analyzed for hemizygous and homozygous deletions by Southern blot techniques using genomic probes selected from cosmids across the region. Hemizygous deletions were found in 31% of cases with an additional 10% showing homozygous loss. The use of these probes has defined the commonly deleted area to less than 130 kb, centromeric to the locus D13S272.