bluuebunny/crossref_metadata_2025_split huggingface dataset:
Single-Stranded DNA-Binding Proteins (SSBPs) Regulate the Abundance of the LIM-Homeodomain Protein LHX2 and Augment Its Transcriptional Activity.
Authors: Cai Ying , Xu Zhixiong , Nagarajan Lalitha , Brandt Stephen J. 
Published: October 2019

Abstract
A small family of proteins with putative single-stranded DNA-binding activity has been shown to augment the biological actions of LIM-homeodomain (LIM-HD) transcription factors through the mediation of the LIM domain-binding protein LDB1. We recently established that two of these SSBPs, Ssbp2 and Ssbp3, were components of an E-box-GATA DNA-binding complex in murine erythroid progenitors containing transcription factors Tal1, E2A, and Gata-1 and LIM-only protein Lmo2 and showed that Ssbp2 stimulated E box-GATA DNA-binding activity by inhibiting Ldb1 ubiquitination and Ldb1 and Lmo2 turnover (Genes & Dev.21:942–955, 2007). Since LIM-HD proteins are substrates of different E3 ubiquitin ligases than LIM-only proteins and have the additional property of binding DNA, we sought to determine the effect of SSBPs on LIM-HD expression and function. Using the prototype LIM-HD protein Lhx2 and one of its best-characterized target genes, Cga, for analysis, we found that an Ssbp3-, Ldb1-, and Lhx2-containing complex associated with an Lhx2 binding element in the Cga promoter in vitro and in mouse pituitary cells (alphaT3-1 cell line) in vivo. We then showed that enforced expression of Ssbp2 and Ssbp3 in alphaT3-1 cells increased Lhx2 and Ldb1 protein abundance, Lhx2 DNA-binding activity, and Cga expression and augmented Lhx2 transcriptional activity in an Ldb1-dependent fashion. While Lhx2-Ldb1-Ssbp3 DNA-binding activity increased in Ssbp3- relative to vector-transfected cells, the affinity of this complex for DNA was unaltered. Similar to the effect of Ssbp2 on Lmo2 in murine erythroleukemia (MEL) cells, overexpressed Ssbp3 reduced Lhx2 protein turnover in cycloheximide-treated alphaT3-1 cells without affecting Lhx2 RNA levels. In contrast, knockdown of endogenous Ssbp3, but not Ssbp2 which is expressed at much lower levels in these cells, reduced Lhx2 and Ldb1 abundance, Lhx2 DNA-binding activity, Lhx2, Ldb1, and Ssbp3 loading onto the Cga promoter, Cga promoter activity, and endogenous Cga gene expression. Significantly, neither overexpression nor knockdown of Ssbp2 in MEL cells, which express both the LIM-only protein Lmo2 and LIM-HD protein Lhx2, affected Lhx2 protein abundance, and Lhx2 DNA-binding activity was undetectable in nuclear extracts from these cells despite the presence of immunoreactive Lhx2. These studies indicate that SSBP augmentation of LIM-HD function results from Ldb1-mediated inhibition of LIM-HD protein turnover and increased assembly of a LIM-HD/LDB1/SSBP DNA-binding complex. The much greater affinity for LDB1 of LIM-only compared to LIM-HD proteins is likely a major determinant of the SSBP effect on LIM-HD protein abundance. Finally, these findings are consistent with cell type-specific contributions of different SSBPs, even for similar LDB1-dependent actions.
Human FLT3/FLK2 Targets Hematopoietic Stem Cells and Granulocyte/Macrophage Progenitors.
Authors: Kikushige Yoshikane , Yoshimoto Goichi , Miyamoto Toshihiro , Ishikawa Fumihiko , Iwasaki Hiromi , Akashi Koichi 
Published: October 2019

Abstract
FLT3/FLK2, a member of the receptor tyrosine kinase family, plays a critical role in maintenance of hematopoietic homeostasis, and the constitutively active form of the FLT3 mutation is one of the most common genetic abnormalities in acute myelogenous leukemia. In murine hematopoiesis, Flt3 is not expressed in self-renewing long-term hematopoietic stem cells (LT-HSCs), but its expression is restricted to the multipotent and the lymphoid progenitor stages at which cells are incapable of self-renewal. In order to test whether Flt3 expression can delineate such a developmental pathway also in human hematopoiesis, we have analyzed the expression of human Flt3 (hFlt3) in prospectively-purified human stem and progenitors (PNAS 2002) by utilizing 7-color FACS and a highly efficient xenograft systems. We have found that Flt3 expression in early hematopoiesis is completely different between human and mice: hCD34+hCD38-hCD90+Lin-LT-HSCs capable of long-term reconstitution in xenogeneic hosts uniformly express hFlt3, and its expression is upregulated through hCD34+hCD38+hCD45RA-hCD123+Lin-common myeloid progenitors (CMPs) to hCD34+hCD38+hCD45RA+hCD123+Lin-granulocyte/macrophage progenitors (GMPs), but hCD34+hCD38+hCD45RA-hCD123-Lin- megakaryocyte/erythrocyte progenitors (MEPs) shut off its expression in human. Furthermore, we have also demonstrated that hFlt3 signaling can prevent stem and progenitors from apoptotic cell death in vitro without any effects on lineage fate decision. Next, we tried to find key molecules for Flt3-Flt3 ligand (FL)-mediating anti-apoptotic effect. First, we tested expression pattern of anti-apoptotic Bcl-2 family genes in HSCs, CMPs, GMPs, MEPs and common lymphoid progenitors (CLPs) in human hematopoiesis. Mcl-1, an indispensable survival factor for murine hematopoiesis (Science, 2005), was also expressed at the highest level in human HSCs, whereas Bcl-2 and Bcl-xL was highly expressed in GMPs and MEPs, respectively. Next, we examined whether FL stimulation can upregulate the expression of Bcl-2 family genes in human purified HSCs and progenitors. FL significantly upregulated the expression of Mcl-1, but not of Bcl-2 or Bcl-xL in HSCs as well as CMPs and GMPs. In conclusion, our data show that the distribution of Flt3 is quite different in mouse and human hematopoeisis. Human Flt3 targets LT-HSCs and myeloid progenitors except for MEPs. Flt3 signaling might support cell survival in early hematopoiesis including the HSC and the myeloid progenitor stages through upregulation of Mcl-1. This is a striking example that the expression pattern of key molecules could be significantly different between human and mouse.
N-cadherin Expression Level Distinguishes Reserved Versus Primed States of Hematopoietic Stem Cells.
Authors: Haug Jeffrey S. , He Xi C. , Grindley Justin C. , Wunderlich Joshua P. , Gaudenz Karin , Ross Jason T. , Paulson Ariel , Wagner Kathryn P. , Xie Yucai , Zhu Ruihong , Yin Tong , Perry John M. , Hembree Mark J. , Redenbaugh Erin P. , Radice Glen L. , Seidel Christopher , Li Linheng 
Published: October 2019

Abstract
Within the bone marrow, three hematopoietic stem cell niches have been identified; the osteoblastic niche (Arai et al., 2004; Calvi et al., 2003; Nilsson et al., 2001; Zhang et al., 2003), the vascular niche (Kiel et al., 2005), and the CAR cell niche (Sugiyama et al., 2006). The adhesion molecule N-cadherin has been found associated with the osteoblastic and CAR cell niches, implicating N-cadherin’s function for hematopoietic stem cell (HSC) anchoring and signaling (Arai et al., 2004; Muguruma et al., 2006; Zhang et al., 2003). However, as of yet, a HSC population expressing N-cadherin has not been fully characterized. Therefore, we examined how N-cadherin expression in HSCs relates to their function and lifecycle. Unexpectedly, we found that doses of 5000 bone marrow cells expressing the highest level of N-cadherin (N-cadherinhi) failed to reconstitute hematopoietic lineages in irradiated recipient mice. An explanation for this engraftment failure came with detailed cell surface phenotyping which revealed that these N-cadherinhi cells were primarily Lineage+ and devoid of the characteristic hematopoietic stem pool, Lineage-Sca+cKit+ (LSK) cells. Instead, we found that Flk2-LSK HSCs express a gradient of N-cadherin which could be described as low (N-cadherinlo) to intermediate (N-cadherinint) levels (Figure1).
FACS applications were used to isolate pure populations of these N-cadherinlo and N-cadherinint Flk2-LSK HSCs. Real time RT-PCR (N-cadherin primers crossed the intron between Exon 2 and 3).
(Figure 2), microarray studies, and competitive reconstitution transplantation assays revealed that this N-cadherin division of Flk2- LSK HSCs formed two populations with very distinct properties. In transplantation assays the N-cadherinlo population more robustly reconstituted the hematopoietic system. Principle Component Analysis and gene ontology analysis of microarray data revealed that the N-cadherinlo cells expressed genes that may prime them to respond to signals and to mobilize. This data was confirmed with mobilization studies which showed that HSCs mobilized from bone marrow to spleen were predominantly N-cadherinlo. In contrast, the expression profile of N-cadherinint cells suggests they are more ‘reserved’ and this population was also maintained with HSCs spared by 5-fluouracil (5FU) treatment. Our results suggest that differential N-cadherin expression reflects important functional distinctions between HSC subpopulations. N-cadherinlo HSCs, with their robust reconstitution efficiency and properties similar to mobilized HSCs, may have clinical relevance.
Figure Figure Figure Figure
Junctional Adhesion Molecule-A (JAM-A/JAM-1/F11R) Marks Long-Term Repopulating Hematopoietic Stem Cells.
Authors: Sugano Yasuyoshi , Takeuchi Masaki , Hirata Ayami , Matsushita Hirokazu , Kitamura Toshio , Tanaka Minoru , Miyajima Atsushi 
Published: October 2019

Abstract
Junctional adhesion molecule-A (JAM-A/JAM-1/F11R) is a cell adhesion molecule expressed in epithelial cells, endothelial cells and also hematopoietic cells such as leukocytes, platelets and erythrocytes. However, the expression of JAM-A in hematopoietic stem cell (HSC) had not been known. Here we show that JAM-A is expressed at a high level in the enriched HSC fraction, i.e. CD34+ c-Kit+ cells in embryonic day 11.5 (E11.5) aorta-gonod-mesonephros (AGM) and E11.5 fetal liver (FL) as well as c-Kit+ Sca-1+ Lineage- (KSL) cells in E14.5 FL, E18.5FL and adult bone marrow (BM). While the percentage of JAM-A+ cells in those tissues decreases during the development, the expression in HSC fraction is maintained throughout life. In fact, c-Kit+Sca-1+ cells are enriched approximately 200-fold from whole BM cells by anti-JAM-A antibody alone, i.e. the c-Kit+Sca-1+ cells in whole BM was about 0.15% and that in JAM-A+ cells was about 30%. Colony forming assays reveal that multi-lineage colony forming activity (CFU-mix) in JAM-A+ cells is higher than that in JAM-A- cells in the enriched HSC fraction in all those tissues. HSC transplantation assay revealed that long-term repopulating HSC (LTR-HSC) activity is present in the mice received 100 JAM-A+ KSL (7/9) cells and 300 KSL cells (5/6). Since the ratio of JAM-A+ cells to JAM-A- cells in the KSL fraction is about 6.5:3.5, 100 JAM-A- KSL cells are equivalent to 285 total KSL cells. In contrast to JAM-A+ cells, the mice received 1000 JAM-A- KSL cells, which are equivalent to more than 2850 total KSL cells, failed to engraft for long-term (0/6). These data revealed that long-term repopulating HSC (LTR-HSC) activity is present exclusively in the JAM-A+ cells, but not in JAM-A- cells. Moreover only 100 JAM-A+ cells isolated from whole BM cells by anti-JAM-A antibody alone reconstituted the hematopoietic system for long-term (4/7). Together these results indicate that JAM-A is expressed on hematopoietic precursors in various hematopoietic tissues and is an excellent and convenient marker to enrich LTR-HSC from BM cells.
Addition of Rituximab Improves Progression-Free and Overall Survival in Patients with B-Cell Lymphoma Receiving Doxorubicin-Containing Chemotherapy
Authors: Sakai Tatsunori , Nagai Hirokazu , Watanabe Tomoyuki , Uike Naokuni , Okamura Seiichi , Yano Takahiro , Kawano Fumio , Hanada Shuichi , Sunami Kazutaka , Ikeda Hirokazu , Sawamura Morio , Nishiura Tetsuo , Hotta Tomomitsu , Horibe Keizo 
Published: October 2019

Abstract
Background: Many clinical trials have documented the efficacy of rituximab in B-cell lymphomas. However, it remains unclear whether rituximab will improve long-term prognosis of the patients. This multicenter retrospective cohort study was conducted to evaluate the clinical impact of the drug in the treatment of B-cell lymphomas. Study design: We retrospectively analyzed clinical characteristics, 2-year progression-free survival(2y PFS) and 2-year overall survival(2y OS) of all B-cell lymphoma patients who were newly diagnosed and initially treated with either CHOP-like regimen alone (R(−) group) or in combination with rituximab (R(+) group) between 2000 and 2004 at our 20 hospitals belonging to the National Hospital Organization. Since rituximab was approved in 2002 for indolent B-cell lymphomas and in 2003 for aggressive B-cell lymphomas in Japan, the patients were almost automatically divided into the 2 groups dependent on the year they underwent treatment.
Results: Of the 1,072 patients enrolled, 335 were given rituximab, while 737 did not receive it for the initial induction therapy. 2y PFS was 74.3% and 61.2% for R(+) group and R(−) group, respectively(P<.0001). 2y OS also significantly improved with the addition of rituximab, 86.6% vs 65.3%(P<.0001). In 746 patients with diffuse large B-cell lymphoma, R(+) group (183 patients) and R(−) group (563 patients) showed 2y PFS of 71.6% and 62.2% (P=.0017), 2y OS of 78.5% and 62.5% (P<.0001) respectively. In 195 patients with follicular lymphoma, R(+) group (104 patients) and R(−) group (91 patients) exhibited 2y PFS of 80.1% and 64.5% (P<.0001), 2y OS of 94.9% and 81.5% (P<.0001), respectively.
Conclusion: The addition of rituximab to the chemotherapy regimen significantly improves the clinical outcome in patients with previously untreated B-cell lymphoma regardless of the clinical aggressiveness.
Non-Pegylated Lyposomal Doxorubicin, Cyclophosphamide, Vincristine, Prednisone and Rituximab (R-COMP) as Initial Treatment for Patients with Splenic Marginal Zone Lymphoma (SMZL). A GISL Study
Authors: Iannitto Emilio , Luminari Stefano , Mammi Caterina , Minardi Viviana , Merli Francesco , Angrilli Francesco , Stelitano Caterina , Cesaretti Marina , Franco Giovanni , Carella Angelo M. , Federico Massimo 
Published: October 2019

Abstract
Background: SMZL is an indolent lymphoma, presenting with massive splenomegaly generally associated with intrasinusoidal bone marrow infiltration. The encapsulation of doxorubicin into non-pegylated liposomes allows targeting of the drug to affected organs including spleen, lymphnodes and bone marrow.
Methods: In 2005 the GISL started a phase II study for the treatment of patients with histologically confirmed SMZL, investigating safety and clinical profile of 6 courses of a modified R-CHOP regimen in which standard doxorubicin was substituted with non pegylated lyposomal doxorubicin (NPLD) used at the same doses (50mg/m2) (R-COMP). Main inclusion criteria were age > 18 yrs, normal cardiac function and active disease (at least one of the following; Hb <10g/dl; plt <100.000/mmc, symptomatic splenomegaly, elevated LDH, B symptoms, extrasplenic disease, LDT <12 months). Splenectomy was allowed prior to treatment start only in case of symptomatic spleen enlargement. The study was planned according to a two-stage Simon design using overall response rate as primary endpoint. We present the results of the analysis performed after the completion of study stage 1. The access to stage 2 is allowed if at least 12 responses are recorded among among the first 19 evaluable cases.
Results: As of January 2007, 20 patient were enrolled with the following characteristics; median age 63 years (30–80), Hb <10g/dl in 20%, Lymphocytes > 5000/mmc in 65%, elevated LDH in 65%; 2 patients were splenectomized before treatment start. One patient was not available for response assessment. A clinical response was observed in all remaining 19 cases (ORR 100%); 12 (63%) cases obtained a CR. So far only one patient progressed at +1 month from treatment. Treatment was well tolerated with grade III/IV neutropenia in 8 patients (42%), grade III pulmonary toxicity in 1 patient and grade II peripheral neuropathy in 5 cases. In one case a reversible cardiac failure was reported after 1 month from the end of treatment.
Conclusions: In conclusion 6 cycles of R-COMP combination represent a safe and promising treatment option for patients with clinically active SMZL.
A Variant Allele of the Gene Growth Factor Independence 1 (GFI1) Is Associated with Acute Myeloid Leukemia.
Authors: Khandanpour Cyrus , Thiede Christian , Nückel Holger , Lohmann Dietmar , Horsthemke Bernhard , Siffert Winfried , Neubauer Andreas , Grzeschik Karl-Heinz , Ehninger Gerhard , Dührsen Ulrich , Möröy Tarik 
Published: October 2019

Abstract
Acute myeloid leukemia (AML) is characterized by an impaired differentiation and abnormal growth of myeloid-progenitor cells, resulting in an accumulation of malignant blast cells in the bone marrow. It represents 1% of all malignancies with overall incidence of 4.5 per 100 000 adults. About 10% of AML patients carry a chromosomal translocation t(8;21) that leads to the production of an AML1/ETO fusion protein. We have previously shown that mice lacking the transcription factor Gfi1 (Growth factor independent 1) show an accumulation of aberrant myelo-monocytic cells reminiscent of myeloproliferative disorders in patients and that Gfi1 is required to maintain the self-renewal and differentiation capability of hematopoietic stem cells. We show here that a variant allele of the gene encoding the transcriptional repressor GFI1, (GFI136N), is associated with AML in three independent Caucasians patient cohorts with an odds-ratio of 2.89 (p=2 x 10–5). The GFI136N variant occurred in 469 AML patients with an allele frequency of 0.064 compared to 0.023 in 503 healthy controls. Patients homozygous for the common form of GFI1 (GFI136S) and patients either heterozygous or homozygous for GFI136N did not differ with regard to the occurrence of AML with specific FAB subtypes, cytogenetic findings or Nucleophosmin 1 mutations. The variant GFI136N did not alter disease progression of AML overall, but correlated with a worse prognosis for patients carrying the t(8;21) chromosomal translocation. Here, the 5 year survival rate was 64% for GFI136S homozygous patients compared to 40% for patients carrying at least one allele of GFI136N. The sub-nuclear localization of GFI136S or GFI136N was different when transiently expressed in 3T3 cells. GFI136S was located mainly at the nuclear border, whereas GFI136S was distributed in a dotted pattern in the nucleus. In addition, we found that GFI136S, but not the variant GFI136N protein co-localized with AML1/ETO in the nucleus. Both GFI136S and GFI136N were able to repress transcription in established reporter gene assays. However, whereas AML/ETO was able to inhibit this activity of GFI136S, the variant GFI136N form was refractory to this inhibition by AML1/ETO, suggesting that the AML1/ETO-GFI1 interaction may be one of the factors responsible for a favorable outcome of t(8;21) positive AML. Our study indicates that the GFI136N variant allele may serve as a novel genetic marker to measure genetic predisposition for the development of AML and provides a first indication that this specific genetic variation at the Gfi1 locus affects the clinical outcome of t(8;21) positive AML patients.
No Difference in Risk of Recurrent Venous Thrombosis between Men and Women. Results from a Family Cohort Study in 3356 Subjects.
Authors: Lijfering Willem M. , Coppens Michiel , Veeger Nic J.G.M. , Middeldorp Saskia , Hamulyak Karly , Prins Martin H. , Buller Harry R. , van der Meer Jan 
Published: October 2019

Abstract
Recent studies have suggested that men are at higher risk of recurrent venous thrombosis than women. It has been proposed to continue anticoagulant treatment after the first episode of thrombosis for a longer period in men, and to search for unidentified prothrombotic abnormalities in men that could explain these findings. However, men and women differ with respect to hormonal risk factors (pregnancy, oral contraceptives), and known thrombophilic defects did not show to increase the risk of recurrence. Moreover, follow-up in previous studies was relatively short (maximum 8 years). We analyzed sex differences in risk of recurrence in a family cohort of 3356 subjects (877 probands, 2479 relatives), who enrolled 5 studies to assess the absolute risk of venous thrombosis associated with currently known thrombophilic defects. Life-time risk of recurrence was calculated, related to sex, follow-up time, type of first and recurrent event (provoked, idiopathic), and thrombophilic defects. Of 816 subjects with a first episode of venous thrombosis, 337 (41%) had a recurrence after discontinued anticoagulant treatment. Overall relative risk of recurrence was 1.8 (95% CI, 1.5–2.3) in men compared to women. Women were younger at time of their first event (mean 34 years vs. 44 years, P< 0.001) and at time of recurrence (40 years vs. 48 years, P< 0.001). Excluding provoked (recurrent) venous thrombosis, the relative risk was 1.2 (95% CI, 0.8–1.7), while mean age at recurrence was comparable in men and women (50 years vs. 49 years, P= 0.595). Women revealed recurrence after a longer period than men (P=0.003), but this difference was not demonstrated if only idiopathic events were considered (P=0.938) (Figure). Recurrences were observed in 111/187 subjects (59%) with antithrombin, protein C or protein S deficiency, compared to 159/479 subjects (33%) with factor V Leiden, prothrombin G20210A or high factor VIII levels (P< 0.001). Within these subgroups, the risk of recurrence after an idiopathic event was comparable in men and women. We conclude that life-time risk of recurrent venous thrombosis is not different between men and women. A difference can be observed when the follow-up period is relatively short and is explained by a younger age of women at time of the first episode of venous thrombosis due to pregancy/puerperium and oral contraception and a longer interval between provoked first episode and recurrence in women.
Figure Figure