bluuebunny/crossref_metadata_2025_split huggingface dataset:
Human Conventional and Plasmacytoid Dendritic Cells Can Originate from Both Lymphoid and Myeloid Progenitors in a New Humanized Mouse System.
Authors: Ishikawa Fumihiko , Iino Tadafumi , Niiro Hiroaki , Yoshida Shuro , Miyamoto Toshihiro , Shigematsu Hirokazu , Shultz Leonard D. , Harada Mine , Akashi Koichi 
Published: April 2020

Abstract
Dendritic cells play a key role in host defense by presenting exogenous antigens to T cells. Two dendritic cell subsets, conventional dendritic cells (cDCs) and plasmacytoid dendritic cells (pDCs), express distinct repertoire of Toll-like-receptors and recognize different antigens. We previously reported that murine cDCs and pDCs differentiate via either the myeloid or the lymphoid pathway (Shigematsu et al. Immunity ). It is, however, still unclear whether human cDCs and pDCs develop from myeloid, lymphoid or both lineages. In order to analyze the in vivo differentiation of human dendritic cells, we employed the newly-developed xenotrasplant assay system which utilizes newborn NOD-scid/IL2rgnull mice (Ishikawa et al., Blood, in press). Transplantation of 104 Lin-CD34+CD38- hematopoietic stem cells into sublethally irradiated newborn NOD-scid/IL2rgnull mice resulted in generation of all hematopoietic and lymphoid components for a long-term via physiological intermediates such as common myeloid progenitors (CMP) and common lymphoid progenitors (CLP). We found that in this system, dendritic cell subcomponents such as hCD11c+hIL3Ralow cDCs and hCD11c-hIL3Rahigh pDCs, efficiently developed in recipients’ bone marrow, spleen and peripheral blood. To elucidate the origin of human mDCs and pDCs, we purified CMP or CLP from the cord blood, and transplanted these cells into sublethally irradiated newborn NOD-scid/IL2rgnull mice via facial vein. At 4-6 weeks post-transplantation, CMP gave rise only to myeloid cells such as erythroid cells, platelets and granulocytes, while CLP exclusively generated T, B and NK cells. Interestingly, in either mouse group injected with CMP or CLP, cDCs and pDCs were easily detected in the spleen and in the bone marrow. Phenotypic and RT-PCR analyses of purified CMP- or CLP-derived DCs revealed that DCs possessed similar phenotypic characteristics, and transcription profiles in TLR families, BDCA antigens and costimulation molecules, irrespective of their lineage origin. Thus, human cDCs and pDCs develop through both myeloid and lymphoid pathways as in case of mouse hematopoiesis. Further characterization of DCs of different lineage origin is currently performed by microarray analyses in order to find genes specifically expressed in each DC subset.
p15Ink4b Maintains Normal Levels of Granulocyte-Macrophage Progenitors In Vivo.
Authors: Rosu-Myles Michael , Wolff Linda 
Published: April 2020

Abstract
Maintaining a balance between the proliferation and differentiation of hematopoietic stem and progenitor cells is crucial for normal maintenance of the hematopoietic system. The INK4 family of cyclin-dependent kinase inhibitors traditionally function in regulating cell proliferation by blocking G1/S phase transition during cell cycle. Loss of expression of one INK4 family member, p15INK4B, has been associated with acute myeloid leukemia (AML) and myelodysplasia and mice that lack p15Ink4b are more prone to developing retrovirus-induced AML. These data suggest an important role for p15INK4B in myeloid differentiation. Here we examined the hematopoietic progenitor pool in p15Ink4b deficient (Ink4b−/−) mice to determine its potential role in regulating hematopoietic precursors. In myeloid progenitor colony assays, bone marrow (BM) from Ink4b−/− mice were found to contain a 1.4 fold greater number of progenitors committed to the formation of granulocytes and macrophages (CFU-GM). This in vitro data was supported by flow cytometric analysis which determined that Ink4b−/− BM contained a 3-fold greater proportion of granulocyte-macrophage progenitors (GMP) (11+/−1.2% vs 34+/−9%) concomitant with a 2-fold decrease in common myeloid progenitors (CMP) (56+/−2 % vs 34+/−7 %). GMP isolated from Ink4b−/− BM also demonstrated a 3-fold greater propensity to form CFU-GM. Despite these differences, the proportion of cycling GMP or CMP in Ink4b−/− and wt mice were identical as determined by propidium iodide and Hoecsht dye DNA stains and in vivo BrdU incorporation. However, in response to specific cytokines, Ink4b−/− CMP showed an increased potential for GMP differentiation and a decreased capacity to form megakaryocyte-erythroid progenitors (MEP). Our work demonstrates that p15Ink4b functions in maintaining normal levels of CFU-GM and may regulate CMP differentiation in response to specific factors.
CD97 Is Differentially Expressed on Murine Hematopoietic Stem Cells and Progenitor Cells.
Authors: van Pel Melissa , Hagoort Henny , Willemze Roel , Hamann Jorg , Fibbe Willem E. 
Published: April 2020

Abstract
CD97 is a member of the EGF-TM7 family of class II seven-span transmembrane receptors and is broadly expressed on hematopoietic cells including lymphocytes, granulocytes, and monocytes. We have recently demonstrated that CD97 is involved in IL-8-induced hematopoietic stem cell (HSC) mobilization (Blood (2003) 102:455a). To determine a possible role of HSC in this process, we studied the expression of CD97 on HSC. Murine HSC are characterized as c-KitPOSThy-1LOLinNEG/LOSca-1POS and isolation of these cells involves a multistep process consisting of lineage depletion and positive selection.
We first studied expression levels on murine bone marrow (BM) cells using a CD97 specific monoclonal antibody (clone 1B2) and FACS analysis. Based on CD97 expression levels, BM cells were then sorted into different fractions and further characterized in colony-forming assays, CAFC assays and in an in-vivo transplantation model.
FACS analysis of BM cells showed three major populations i.e. CD97HI, CD97INT and CD97NEG cells (71.5%, 24.4% and 4.4% of total BM cells respectively). Analysis of CFU-GM colony forming capacity of these BM subsets revealed that the majority of colony-forming cells were present in the CD97NEG (7142 ± 5057 CFU-GM) population compared to CD97HI (178 ± 170CFU-GM) and CD97INT (3047 ± 2902 CFU-GM per 106 BM cells). Analysis of CAFC frequencies of CD97HI, CD97INT and CD97NEG BM cells showed that CAFC-day 35 activity resided in the CD97INT BM population (3.0 ± 1.2 vs. 0.9 ± 0.1 CAFC-day 35 per 105 cells for CD97INT and total BM respectively), whereas no CAFC-day 35 activity was found in CD97HI and CD97NEG BM fractions. In addition, FACS analysis revealed that the majority (82.6 %) of c-kitPOSthy-1LOLinNEG/LO cells were present in the CD97INT BM population. To investigate the in-vivo repopulating ability of the different CD97 BM subsets, lethally irradiated (9.5 Gy) BALB/c recipient mice (n=10 per group) were reconstituted with 105 syngeneic BALB/c total BM or with CD97 sorted BM cells. Repopulating capacity entirely resided in the CD97INT subset (repopulation rate 90% versus 0% in the CD97HI and CD97NEG subset).
These data indicate that 1) CD97 is differentially expressed on HPC and HSC and that 2) CD97 expression can be used to separate colony forming cells from repopulating hematopoietic stem cells.
Human Mesenchymal Stem Cells Enhances the Growth of Acute Myeloid Leukemia Cells In Vivo.
Authors: Cen Jian-nong , Chen Zi-xing , Qian Jun , Li Zhen-jiang , Qiu Qiao-cheng 
Published: April 2020

Abstract
Human mesenchymal stem cells (MSC) are adhering cells capable of self-renew, proliferation and multilineage differentiation. MSC have the capacity to differentiate into osteoblasts, chondroblasts, myocytes and adipocytes when exposed to appropriate in vivo or in vitro stimuli. MSC descendants are involved in the formation of stroma maintaining the hemopoiesis. In this study, we investigated whether in vivo coinjection of hMSCs could enhance acute myeloid leukemia cells growth. Acute myeloid leukemia line (SHI-1) cells were grown in IMDM with 10%FCS. The hMSCs in adult BM were isolated and cultured in 60%DMEM (low glucose) and 40% MCDB-201 medium, 5%FCS, ITS+1. The hMSCs were immunotyped by using FACS. The differentiation ability in vitro towards osteoblasts and adipocytes was examined. BABL/c nude mice, aged 5 to 6 weeks, were used to explore the hMSCs’ function in vivo. SHI-1cells and hMSCs were prepared either as single-cell type suspensions (3×106 cells in 100ul PBS) or a mixture of cells (3×106 SHI-1 cells plus 4×105 hMSCs in 100ul PBS ). Subcutaneous injection was performed in alar area. Injection of hMSCs alone was used as control. Mice were examined 3 times a week and tumor growth was evaluated by measuring the length and width of tumor mass. After 30 days, animals were sacrificed and tumor masses were weighed. Our experiments showed that the hMSCs have the potential of proliferation and the capacity to differentiate into osteoblasts and adipocytes in vitro. The immunophenotype of MSCs is CD34−,CD45−,CD105+,CD19−,CD13+,CD14−.10 days after injection with a mix of cells small tumor mass occurred in mice while no tumor mass could be observed in mice injected SHI-1 cells alone. Upon day 20, small tumor mass started to emerge in mice injected with SHI-1 cells alone. By the end of the experiment, mice were sacrificed and tumors were recovered. The weight of tumor masses from the mouse injected with mixed cells of SHI-1 and hMSCs was 0.42±0.18 g and from the mouse injected SHI-1 cells alone was 0.11±0.089 g, (P&lt;0.01). No tumor masses could be found in mice injected with hMSCs alone. From this animal model, we proposed that human mesenchymal stem cells favors the growth of acute myeloid leukemia cells in vivo.
Physiological Gradients of Serum Albumin Regulate SDF-1/CXCR4 Dependent Migration.
Authors: Ryser Martin F. , Roesler Joachim , Malech Harry L. , Roesen-Wolff Angela , Brenner Sebastian 
Published: April 2020

Abstract
Hematopoietic stem cell (HSC) egress to the circulation and homing to the bone marrow (BM) are regulated by interactions between CXCR4 and SDF-1. Serum albumin is the major protein component of plasma. Concentration gradients of albumin between plasma and interstitial fluid account for the colloid osmotic pressure, which is a central regulator of the intravasal blood volume. SDF-1/CXCR4 dependent migration of mobilized peripheral blood CD34+ hematopoietic stem cells (PBSC) was studied in transwell migration assays. We compared the effect of RPMI diluted Heparin-plasma (50% plasma, 50% RPMI) versus undiluted plasma as a migration medium. To our surprise the use of undiluted plasma in the upper chamber containing the cells and diluted plasma in the lower chamber containing 100ng/ml SDF-1, resulted in a 3 fold increase of migrating PBSCs compared to experiments without a gradient (undiluted versus undiluted plasma or diluted versus diluted plasma) while diluted plasma in the upper chamber and undiluted in the lower chamber inhibited the SDF-1 dependent migration 3,5 fold. To further characterize this observation we removed high molecular weight proteins (&gt;50kd) by filtration of the plasma. The filtrate was used to dilute plasma to obtain samples with reduced protein contents. Transwell experiments showed that negative gradients of plasma proteins (high concentration in the upper chamber vs low concentration in the lower chamber) stimulate (up to 2 fold) while positive gradients inhibit SDF-1/CXCR4 dependent migration of PBSC (up to 3 fold). Migration experiments were repeated with RPMI, supplemented with varying concentrations of serum albumin as migration medium. Negative gradients of albumin stimulated migration while positive gradients were inhibiting. Interestingly, a gradient of 4% albumin in the upper chamber and 1% albumin in the lower chamber enabled migration in the absence of a SDF-1 gradient (100ng/ml SDF-1 in both upper and lower chamber). Albumin gradients did not stimulate migration in the absence of SDF-1. The absence of serum albumin in both chambers abolished the SDF-1/CXCR4 dependent migration of PBSCs. Our results show that gradients of serum albumin strongly influence the SDF-1/CXCR4 dependent migration of PBSCs. Negative gradients of albumin between blood and bone marrow might be supportive for the homing of PBSC to the stem cell niche, which suggests a new function of the multitask protein serum albumin.
Human Mesenchymal Stem Cells as Precursors of Functional Fibroblastic Reticular Cells: Implications for the Physiopathology of Secondary Lymphoid Organs.
Authors: Tarte Karin , Ame-Thomas Patricia , Maby Hélène , Caulet-Maugendre Sylvie , Jean Rachel , Monvoisin Céline , Lamy Thierry , Fest Thierry 
Published: April 2020

Abstract
Several subsets of stromal cells are found among secondary lymphoid organs where they play a key role in the initiation and maintenance of immune response. In particular, fibroblastic reticular cells (FRC) of the paracortex secrete extracellular matrix (ECM) components that constitute a dense network of conduits allowing antigens carried within the subcapsular afferent lymph to reach the lumen of the medullary high endothelial venules. FRC produce also several chemokines that recruit T, B, and dendritic cells from blood and favour their reciprocal interactions. In addition, follicular dendritic cells (FDC) are located exclusively into germinal centers and allow normal B-cell selection through a complex set of survival signals, including BCR-mediated signal, chemokines and adhesion molecules. FRC and FDC networks are phenotypically and probably functionally altered during development of follicular lymphomas and diffuse large B cell lymphomas, the two most frequent Non-Hodgkin Lymphomas. FRC and FDC are supposed to be of mesenchymal origin even if no conclusive work has been conducted to date in human. We have obtained 15 tonsil-derived stromal cell lines, that displayed all the morphologic, phenotypic, and functional characteristics of FRC, including synthesis of inflammatory (CXCL10, CXCL9, CCL5) and lymph-node specific (CCL19, CCL21) chemokines, and secretion of ECM organized in a reticular meshwork after long-term culture in the presence of TNF-α and lymphotoxin-α1β2 (LT). These cells induced tonsil leukocyte migration and adhesion in vitro. Tonsil-derived stromal cells expressed LTβR, TNFR, and CD40 but were negative for FDC specific markers, such as CD21 or CXCL13, even following in vitro stimulation by TNF-α, LT, and trimeric CD40L. Interestingly, such TNF and LT-dependent FRC differentiation could also be induced in adult bone marrow-derived mesenchymal stem cells (MSC). In addition, MSC-like cells able to differentiate along osteogenic, adipogenic, and chondrogenic lineages at the clonal level were found in normal tonsils. These data shed new lights on our current understanding of lymph node stromal cell origin and strongly suggest that MSC are the precursors of FRC in secondary lymphoid organs, and perhaps in bone marrow in case of FL involvement where ectopic lymph node-like stromal cells are detected in close association with tumor cells. In conclusion, MSC and their progeny trigger differential immune effects, depending on cytokine context, localization and cell contact with immune cells. These properties are probably modified during lymphomas where the contact between malignant B cells and stromal cells is crucial for tumor development.
Increased Red Cell Adhesion Is Associated with Overt Stroke in Sickle Cell Disease.
Authors: Rennie Kimberly M. , Scott J. Paul , Panepinto Julie A. , Hillery Cheryl A. 
Published: April 2020

Abstract
The major cause of morbidity and mortality in sickle cell disease (SCD) is tissue ischemia and infarction due to vascular obstruction. One of the most devastating vascular complications of SCD is clinical stroke caused by occlusion of the large cerebral arteries in the Circle of Willis or its branches. Overt stroke occurs with obvious speech or motor deficits in approximately 10% of children with SCD. Additional complications due to stroke in SCD include an increased risk of secondary disabilities such as mental retardation and learning disabilities, with the most severe forms of neurocognitive impairments associated with large vessel disease (overt stroke). When compared to normal RBCs, sickle red blood cells (SS-RBCs) have markedly increased adhesion to the vascular endothelium and several subendothelial matrix proteins. The increased sickle RBC adhesion likely plays a significant role in the pathogenesis of vascular obstruction. We have previously shown that SS-RBCs have enhanced adhesion to the plasma and extracellular matrix protein thrombospondin-1 (TSP) under conditions of flow in vitro. In addition, we have observed that the level of adhesion of RBC adhesion varies from patient to patient (i.e., there are some patients whose RBCs tend to consistently be “stickier” or “less sticky” than other patients). In this study, we proposed that patients who develop large vessel (Circle of Willis and major branches) central nervous system (CNS) disease (e.g., clinical stroke) have higher baseline levels of RBC adhesion. Thus, we examined the level of sickle RBC adhesion to immobilized TSP under flow conditions from patients with SCD with and without stroke. We recruited 87 male and female patients over the age 3 yrs with HbSS disease from the Wisconsin Sickle Cell Disease Comprehensive Center. Of these, 8 patients later developed an overt stroke following their participation in this study. None of the patients were transfused prior to studying RBC adhesion. After obtaining informed consent, blood samples were collected into citrate from patients with HbSS disease. Washed RBCs were perfused through flow chambers previously coated with TSP (2 μg/cm2) at a wall shear stress of 1 dyne/cm2 that mimics the forces in post-capillary venules and optimizes sickle RBC adhesion. After rinsing, adherent RBCs per unit area were counted in four random fields in each of two duplicate wells by direct microscopic visualization. We found that patients with SCD who developed an overt stroke (n=8) had a higher level of RBC adhesion (1436 ±101 RBCs/mm2) compared to 79 unselected patients with SCD who had a mean RBC adhesion of 1004 ± 53 RBCs/mm2 (p=0.016, student t-Test). Thus, RBCs derived from the subpopulation of patients with SCD who developed an overt stroke associated with large vessel disease have an abnormally enhanced adhesive phenotype. These data suggest that enhanced levels of RBC adhesion may play a role in the development of large vessel disease in SCD.
Long Term Follow-Up of Pediatric Sickle Cell Disease Patients with Conditional Velocities on Transcranial Doppler (TCD).
Authors: Coïc Lena , Verlhac Suzanne , Lesprit Emmanuelle , Fleurence Emmanuelle , Bernaudin Francoise 
Published: April 2020

Abstract
Abnormal TCD defined as high mean maximum velocities &gt; 200 cm/sec are highly predictive of stroke risk and justify long term transfusion program. Outcome and risk factors of conditional TCD defined as velocities 170–200 cm/sec remains to be described. Patients and methods Since 1992, 371 pediatric SCD patients (303 SS, 44 SC, 18 Sß+, 6 Sß0) were systematically explored once a year by TCD. The newborn screened cohort (n=174) had the first TCD exploration between 12 and 18 months of age. TCD was performed with a real-time imaging unit, using a 2 MHz sector transducer with color Doppler capabilities. Biological data were assessed at baseline, after the age of 1.5 years and remotely of transfusion or VOC. We report the characteristics and the outcome in patients (n=43) with an history of conditional TCD defined by mean maximum velocities ranging between 170 and 200 cm/s in the ACM, the ACA or the ICA.
Results: The mean follow-up of TCD monitoring was 5,5 years (0 – 11,8 y). All patients with an history of conditional doppler were SS/Sb0 (n=43). Mean (SD) age of patients at the time of their first conditional TCD was 4.3 years (2.2) whereas in our series the mean age at abnormal TCD (&gt; 200 cm/sec) occurrence was 6.6 years (3.2). Comparison of basal parameters showed highly significant differences between patients with conditional TCD and those with normal TCD: Hb 7g4 vs 8g5 (p&lt;0.001), MCV 82.8 vs 79 (p=0.047). We also had found such differences between patients with normal and those with abnormal TCD (Hb and MCV p&lt; 0.001). Two patients were lost of follow-up. Two patients died during a trip to Africa. Conditional TCD became abnormal in 11/43 patients and justified transfusion program. Mean (SD) conversion delay was 1.8 (2.0) years (range 0.5–7y). No stroke occurred. 16 patients required a treatment intensification for other indications (frequent VOC/ACS, splenic sequestrations): 6 were transplanted and 10 received HU or TP. Significant risk factors (Pearson) of conversion to abnormal were the age at time of conditional TCD occurrence &lt; 3 y (p&lt;0.001), baseline Hb &lt; 7g/dl (p=0.02) and MCV &gt; 80 (p=0.04). MRI/MRA was performed in 31/43 patients and showed ischemic lesions in 5 of them at the mean (SD) age of 7.1 y (1.8) (range 4.5–8.9): no significant difference was observed in the occurrence of lesions between the 2 groups. Conclusions This study confirms the importance of age as predictive factor of conditional to abnormal TCD conversion with a risk of 64% when first conditional TCD occured before the age of 3 years. TCD has to be frequently controled during the 5 first years of life.