bluuebunny/crossref_metadata_2025_split huggingface dataset:
Anemia and Ineffective Erythropoiesis Caused by Somatic RAS Mutation.
Authors: Braun Benjamin S. , van Ziffle Jessica , Gavin Joehleen , Tuveson David A. , Jacks Tyler , Shannon Kevin 
Published: October 2019

Abstract
Ras proteins modulate cell fates by integrating extracellular stimuli and transducing signals that regulate proliferation, survival, and differentiation via downstream effector cascades. Somatic activating mutations in RAS oncogenes are found in approximately one third of cases of myelodysplastic syndrome (MDS), and are common in myeloproliferative disorders (MPDs) such as CMML and JMML that frequently have a dysplastic component. We have modeled these human diseases in the mouse using a conditional allele of oncogenic Kras, which is activated in mice bearing the inducible Mx1-Cre transgene by injection with polyinosinic-polycytidilic acid (pI-pC). Mice treated with pI-pC to induce K-rasG12D expression at 21 days of life develop not only myeloid proliferation, but also progressive anemia which is the likely cause of death with median survival 84 days after injection. Erythroid precursors are abundant in spleens of anemic mice, suggesting ineffective erythropoiesis. These features are highly reminiscent of human MDS, and suggest that anemia in MDS is a direct consequence of hyperactive RAS signaling. Further analysis reveals that although erythroblasts are absent from the bone marrow, earlier erythroid progenitors such as BFU-E and CFU-E are abundant in both bone marrow and spleens of anemic mice. However, despite hyperproliferation of primitive erythroid cells, there is a block in terminal erythroid differentiation. This is also seen in primary E14.5 fetal liver cells acutely induced to express K-rasG12Din vitro, and in wild type recipients of Mx1-Cre, KrasG12D bone marrow, demonstrating this to be a cell-intrinsic property of erythroid progenitors expressing oncogenic Ras. Together, these findings support a model in which RAS mutations in MDS both confer a proliferative advantage to a neoplastic clone as well as directly impede differentiation, resulting in ineffective erythropoiesis and anemia. The improved efficiency of differentiation observed in spleen relative to bone marrow also suggests that microenvironmental influences modify the cell-intrinsic effects of oncogenic Ras.
Inhibition of p38 MAPK by SCIO-469 Suppresses TNF Generation and Promotes CD34+ Cell Survival in an In Vitro MDS Cell Culture Model.
Authors: Navas Tony A. , Nguyen Aaron N. , Ma Jing Y. , Stebbins Elizabeth G. , Haghnazari Edwin , Heaton Ruth , List Alan F. , Higgins Linda S. 
Published: October 2019

Abstract
Progress in the development of more effective therapeutics for myelodysplastic syndrome (MDS) has been limited by the lack of targets critical to the pathobiology of the disease. Ineffective hematopoiesis in MDS is characterized by accelerated proliferation and premature apoptotic death of progenitors and their progeny that is potentiated by the local generation of inhibitory molecules, including TNFa, TGFß, FasL, and VEGF. To identify upstream regulatory signals that may coordinate activation of inhibitory molecules, we used an in vitro cell culture model incorporating a CD34+ MDS cell line isolated from a RAEB-t patient, normal bone marrow stromal cells (BMSC), and/ or bone marrow mononuclear cells (BMMNC) to determine effects of cell-cell interactions on secretion of inhibitory hematopoietic cytokines. The role of p38 MAP kinase, a regulatory kinase involved in the convergence of inhibitory cytokine activation and signaling, was evaluated in this interaction. We found that p38 MAPK is induced under basal culture conditions in the MDS cell line and is further activated by TNFa or TGFß. In all cases, p38 activation was reduced by SCIO-469, a potent and specific inhibitor of p38a activity. SCIO-469 does not directly block p38 activation, suggesting a feedback loop is interrupted when p38 kinase activity is inhibited in MDS cells. To determine the effects of cellular interactions, the MDS cell line was co-cultured with either BMSC, BMMNCs or both from normal donors, and TNFa and FasL secretion were measured after 3 days incubation. TNFa and FasL were detected in culture supernatants when the MDS cell line was co-cultured with BMMNC but not when co-cultured with BMSC. TNFa secretion by BMMNCs was dependent on MDS cell contact and was significantly inhibited by SCIO-469. The addition of BMSC to the MDS and BMMNC co-culture prevented TNFa elevation, suggesting BMSCs as a dominant source for anti-inflammatory signal(s). VEGF, FGF-ß, TGFß2, BDNF, TIMP-1, TIMP-2 and IL-6 secretion by BMSC was induced by MDS co-culture, whereas SCIO-469 blocked cytokine induction. To determine the effects of SCIO-469 and MDS clone-induced BM cytokine secretion on normal CD34+ proliferation, we co-cultured BMMNCs and BMSC in transwell inserts in the presence or absence of the MDS cell line with or without SCIO-469. CD34+ proliferation was assessed in cells cultured in outer wells. CD34+ progenitors proliferated in culture at the same rate as those co-cultured with BMSC, BMMNC and MDS for 6 days. At longer intervals, viability of progenitors cultured with the MDS line declined, whereas treatment with SCIO-469 abrogated the decrease in CD34+ viability. These results implicate p38a as a critical target in the induction of pro-apoptotic cytokines in MDS, and that selective inhibition of p38 by SCIO-469 may provide a novel therapeutic strategy for MDS.
Ship Is Essential for Both Endotoxin- and CpG-Induced Tolerance and for Their Cross-Tolerance.
Authors: Sly Laura M. , Omeis Stephanie L. , Rauh Michael J. , Krystal Gerald 
Published: October 2019

Abstract
An initial exposure to lipopolysaccharide (LPS, also known as endotoxin), which activates macrophages via Toll-like receptor 4 (TLR4), induces a transient state of hypo-responsiveness to a subsequent challenge with LPS. The mechanism underlying this phenomenon, termed endotoxin tolerance, remains poorly understood although the activation/upregulation of a number of negative regulators has been implicated. Related to this, we recently demonstrated that the SH2-containing inositol-5′-phosphatase, SHIP, which is a key negative regulator of the PI3K pathway in hematopoietic cells, is essential for endotoxin tolerance. Specifically, we found that SHIP−/− bone marrow derived macrophages (BMmΦs) do not display endotoxin tolerance. Moreover, an initial LPS treatment of wild-type BMmΦs increases the level of SHIP protein 10 fold and this increase is critical for the hypo-responsiveness to a subsequent LPS stimulation. Interestingly, this increase in SHIP protein is mediated by the LPS-induced production of autocrine-acting TGFβ and neutralizing antibodies to TGFβ, as well as antisense oligonucleotides to SHIP, block LPS-induced endotoxin tolerance. In vivo studies with SHIP+/+ and −/− mice confirm these in vitro findings and show a correlation between the duration of endotoxin tolerance and elevated SHIP levels (Sly et al., Immunity, in Press). We have now followed up on these studies by exploring the role of SHIP in the stimulation of other Toll-like receptors. Specifically, we asked whether SHIP plays a role in repressing CpG-induced pro-inflammatory cytokine production, which is mediated via the activation of TLR9. Our results, using SHIP+/+ and −/− BMmΦs, suggest that SHIP negatively regulates this TLR as well and is required for CpG-induced tolerance. Moreover, we found that CpG treated SHIP−/− BMmΦs show higher pro-inflammatory cytokine production compared to their SHIP+/+ counterparts when challenged with LPS. This indicates that SHIP plays a critical role in dampening down inflammatory responses in the innate immune system.
PPAR-gamma Agonists Inhibit Toll-Like Receptor Mediated Activation of Dendritic Cells Via the MAP Kinase and NF-kB Pathways.
Authors: Mirakaj Valdete , Appel Silke , Grünebach Frank , Weck Markus M. , Reichardt Volker L. , Brossart Peter 
Published: October 2019

Abstract
Dendritic cells (DC) play an important role in initiating and maintaining of primary immune responses. However, little is known about the termination of once induced immunological responses. Cyclopentenone prostaglandins (15d-PGJ2, PGD2) are produced during the late phase of inflammation due to upregulation of COX2 and can lead to the resolution of an inflammation by activation of PPAR-gamma dependent and independent pathways. In this study we analyzed the effects of 15d-PGJ2 and the synthetic PPAR-gamma ligand troglitazone (TGZ) on the immunogenicity of monocyte derived DC upon stimulation with toll-like receptor (TLR) ligands. Activation of PPAR-gamma resulted in a reduced activation of DC via the TLR ligands 2, 3, 4 and 7 characterized by downregulation of CD83, adhesion and costimulatory molecules. Moreover, these cells secreted lower levels of cytokines and chemokines involved in T lymphocyte activation and recruitment including IL-12 and RANTES. In contrast to these results, MCP-1 production was increased due to the treatment with PPAR-gamma agonists. To determine the mechanisms by which PPAR-gamma regulates DC function we performed Western blot analyses and found that the inhibitory effects on TLR induced DC activation were mediated via inhibition of the NF-kB and MAP kinase pathways. Incubation of DC during the differentiation from monocytes with 15d-PGJ2 or TGZ resulted in downregulation of TLR ligands induced phosphorylation of ERK1 as well as reduced expression of nuclear localized members of the NF-kB family. No effect on the expression of MyD88, an adaptor molecule involved in the signal transduction of TLR, was observed. Our results demonstrate that inhibition of the MAP kinase and NF-kB pathways is critically involved in the regulation of TLR and PPAR-gamma mediated signaling in DC an represent a novel negative feed-back mechanism involved in the resolution of immunological responses.
M-CSF Drives Human Cord Blood Monocyte Differentiation along an Alternative Pathway into Suppressive CXCR4highIL-10highIL-12absentTNF-adefective Dendritic Cells.
Authors: Li Geling , Broxmeyer Hal E. 
Published: October 2019

Abstract
M-CSF Drives Human Cord Blood Monocyte Differentiation along an Alternative Pathway into Suppressive CXCR4highIL-10highIL-12absentTNF-αdefective Dendritic cells
Geling Li and Hal E. Broxmeyer. Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN, USA; Walther Oncology Center, Indiana University School of Medicine, Indianapolis, IN, USA; Walther Cancer Institute, Indianapolis, IN, USA
Macrophage colony-stimulating factor (M-CSF) in cooperation with TGF-β1 induces CD34+ hematopoietic progenitor cells to differentiate into Langerhans cells, a subset of immature dendritic cells (DCs) specifically localized in the epidermis. M-CSF levels are dramatically elevated in immunosuppressive conditions and M-CSF deficient mice are osteopetrotic. Therefore, we hypothesized that M-CSF might be involved in the generation of a novel subtype of suppressive DCs which may be located primary in bone marrow where large amounts of SDF-1 are constitutively produced. We also speculated that M-CSF-induced DCs might express the only known ligand of SDF-1, CXCR4 and migrate towards SDF-1. Highly purified umbilical cord blood monocytes (> 98% purity) cultured in the presence of M-CSF, IL-4 and TGF-β1 differentiated into a highly homologous population of cells with typical dendrites and acquired a langerhan cell (LC) phenotype by up-regulated expression of CD1a and E-cadherin. We termed these cells M-LC to distinguish them from regular LCs cultured in the presence of GM-CSF, IL-4 and TGF-β1. In comparison with LC, M-LCs produced a much higher level of IL-10, no IL-12 (detection limit, 4 pg/ml) and a minimal level of TNF-α (21.6 ± 37.5 pg/ml) upon LPS stimulation. LPS-activated M-LCs induced lower allogeneic mixed lymphocyte reaction (MLR) than LPS-activated LCs. Furthermore, exposure to LPS-activated M-LCs rendered a state of low-responsiveness in cord blood naïve CD4+ T cells to further re-stimulation with alloantigens in secondary MLR. M-LCs expressed much higher surface levels of CXCR4 than LCs regardless of their maturation status. M-LCs started to migrate towards SDF-1 at a lower concentration (≥10 fold lower than that required for LCs) and displayed enhanced responsiveness to SDF-1-induced chemotaxis. Our results demonstrate that M-CSF drives monocyte differentiation along an alternative pathway into suppressive CXCR4highIL-10highIL-12absentTNF-αdefective DCs. These novel DCs may be of use to suppress unwanted immune responses in vivo.
The Distinctive Effects of Reactive Oxygen Species (ROS) and Redox Status on the Maturation of Human Monocyte-Derived Dendritic Cells.
Authors: Yamada Hiroko , Arai Toshiyuki , Endo Nobuyuki , Sasada Masataka , Uchiyama Takashi 
Published: October 2019

Abstract
The role of reactive oxygen species (ROS) and redox status on the maturation of dendritic cells (DC) was examined using alpha-phenyl-tert-butylnitrone (PBN) and glutathione reduced form ethyl ester (GSH-OEt). PBN is widely used as a spin trapping agent in electron paramagnetic resonance (EPR) studies. Since PBN reacts with free radical species and stabilizes them, PBN serves as an antioxidant. GSH not only serves as a major antioxidant but also plays a central role in maintaining intracellular redox balance, and GSH-OEt increased the intracellular GSH level. When human monocyte-derived DC were stimulated with LPS, up-regulation of the expression of the surface molecules (HLA-DR, CD40, CD80, CD86 and CD83), production of cytokines (TNF-α and IL-12p70) and allostimulatory capacity were observed. The LPS-induced cytokine production was suppressed by both PBN and GSH-OEt, while the up-regulation of the expression of surface molecules and the allostimulatory capacity were suppressed by only GSH-OEt but not by PBN. The mean values of TNF-α of LPS, LPS+PBN and LPS+GSH-OEt were 1220, 783 and 238 pg/ml, respectively (n=12). Those of IL-12p70 were 632, 358 and 5 pg/ml, respectively (n=12). The EPR study revealed that ROS was generated by LPS and that the ROS generation was attenuated by both PBN and GSH-OEt. Flow cytometric analysis revealed that intracellular GSH content was decreased by LPS and that this reduction was attenuated by GSH-OEt not by PBN. That is, PBN quenched the generated ROS but did not affect the redox status, while GSH-OEt not only quenched the generated ROS but also affect the redox status in the LPS-stimulated DC. The allostimulatory capacity of DC correlates with the expression of surface molecules and it does not depend on IL-12 production. Therefore, our findings suggest that ROS and redox status have distinctive effects on the maturation of DC. The ROS is involved in the cytokine production, while the redox status is involved in the up-regulation of surface molecules and allostimulatory capacity in the LPS-stimulated DC. LPS induces the activation of intracellular signaling cascade via Toll-like receptor 4. The signaling cascade is consist of two distinct pathways, MyD88-dependent and independent pathways. In DC, the MyD88-dependent pathway is involved in the cytokine production, while the MyD88-independent pathway is involved in the up-regulation of CD80 and CD86. The former may be ROS-sensitive, the latter may be redox status-sensitive. Differential regulation of the ROS and the redox status in DC may be possible to adequately modulate inflammatory and immune responses in the disease, such as graft-versus-host disease.
Figure Figure
A Role for Notch Signaling in the Commitment of Human Blood Monocytes to Langerhans Cells.
Authors: Shibasaki Tetsunori , Katayama Naoyuki , Ohishi Kohshi , Masuya Masahiro , Shiku Hiroshi 
Published: October 2019

Abstract
We previously demonstrated that Notch ligand Delta-1 in concert with GM-CSF and TGF-β1 promotes the differentiation of human blood monocytes into Langerhans cells that are characterized by the expression of CD1a, Langerhans-associated granules Langerin, cutaneous lymphocyte-associated antigen (CLA), CC chemokine receptor 6 (CCR6), and E-cadherin. These data extended the functional scope of Notch ligand Delta-1 in human adult hematopoiesis. HES-1 is known to be the target gene by Notch signaling. We examined the effect of Delta-1 on the expression of HES-1 mRNA in CD14+ blood monocytes in the presence of GM-CSF and TGF-β1, using real-time RT-PCR. When CD14+ blood monocytes were cultured with Delta-1, GM-CSF, and TGF-β1, the expression level of HES-1 mRNA increased approximately 10-fold at 24 hours of incubation, compared with the expression level in freshly isolated CD14+ monocytes. However, the expression level of HES-1 mRNA declined at 48 hours of incubation. This finding suggests that Delta-1 may operate at the early stage of the differentiation pathway from CD14+ monocytes to Langerhans cells. To explore this issue more precisely, we cultured CD14+ monocytes in the presence of Delta-1, GM-CSF, and TGF-β1 for 2 days, and subsequently replated the cells into the cultures without Delta-1. At day 7 of culture, cultured cells were harvested and characterized by phenotypic analysis. This initial 2-day exposure of CD14+ monocytes to Delta-1 gave rise to Langerhans cells, similar to the observation obtained with the supplementation of Delta-1 throughout 7-day culture. In turn, when Delta-1 was added at day 2 of culture, Langerhans cells were not induced, but instead the resulting cells exhibited the features of macrophages. Our results indicate that in response to Delta-1, human blood monocytes appear to initiate the differentiation program toward Langerhans cells, while they are incapable of differentiating into Langerhans cells after their commitment to macrophages.
Thalidomide (T) in Combination with Fludarabine (F) as Initial Therapy for Patients (pts) with Treatment Naïve Chronic Lymphocytic Leukemia (CLL): Results of a Phase I Trial.
Authors: Chanan-Khan Asher Alban , Miller Kena , Koryzna Alexandra , Takeshita Kenichi , McCarthy Philip , Mohr Alice , Donohue Kathleen , Bernstein Zale P. , Alam Arif , Czuczman Myron S. 
Published: October 2019

Abstract
CLL is an incurable disease. Standard treatment with F results in an ORR of 63% (CR 20%). Improved RR are noted when F is combined with biologic agents such as rituximab. All pts eventually relapse with limited salvage options. TNF-a is an important cytokine in the pathogenesis of CLL. T is an immunomodulatory drug with anti- TNF-a, anti-VEGF and immunostimulatory activity. We have completed a phase I study combining T with F as an immunochemotherapeutic approach to enhance anti-CLL activity of F. Treatment-naïve pts requiring therapy for CLL were eligible for this study. T was started at D1 and continued for 6 months stepwise in 3 cohorts of T (100,200,300 mg). Standard dose F (25mg/m2 x 5 D every 4 wks) was given for 4–6 cycles starting on D7. Antitumor activity of T alone was assessed at D7 prior to the first F dose. Low-dose coumadin (1 or 2 mg po qd) was used for prophylaxis against venous thromboembolism (VTE). Thirteen pts (9M, 4F; median age 65,range 38–74 yrs) have been enrolled on 3 dose levels (cohort #1 n =6, #2 n=3, #3 n=4). All pts are available for toxicity analysis. Pts were considered evaluable for response if they completed the intended 6 months of T. 3 pts were removed from study for toxicity (2VTE, 1 in the 1st week of therapy prior to F infusion, 2nd during the 4th cycle, 1 Hep C reactivation presumably secondary to F), without evidence of disease progression. 9 pts completed 6 months of therapy and are available for response (5CR and 4PR, ORR of 100%) median follow-up of 12+ (range 6–18+) months. Response to T alone, assessed on D7 of cycle 1, was noted at all dose levels, and no dose-limiting toxicity was noted. Flare reaction (tender swelling of lymph nodes) was noted in 5/13 pts (38%) and was the most common side effect. Rash, fatigue and constipation were noted in 30%, 23% and 15% of the pts, respectively. Of the 60 cycles given on this study, 9 (15%) and 3 (5%) episodes of Grade III and IV non-hematologic toxicities were noted, respectively. In this phase I study, the combination of T with F was well tolerated with improved ORR over F. T alone appears to be active in CLL with clinical activity noted as early as D 7 at all dose levels studied. The combination does not appear to increase the incidence of VTE compared to T alone. Ongoing phase II portion of this study will further establish the potential role of FT in CLL.
Pentostatin and Cyclophosphamide with or without Rituximab Has Significant Activity in Patients with Previously Treated Chronic Lymphocytic Leukemia and Other Low Grade Lymphoid Neoplasms.
Authors: Lamanna Nicole , Kalaycio Matt , Maslak Peter , Jurcic Joseph , Scheinberg David A. , Gencarelli Alison N. , Horgan Denise , Weiss Mark A. 
Published: October 2019

Abstract
Combination therapy with purine analogs, alkylators, and/or monoclonal antibodies represents a promising new approach in the treatment of patients with chronic lymphocytic leukemia (CLL) and other low grade B cell neoplasms. Most regimens have utilized fludarabine as the purine analog, but the severe myelosuppression and immunosuppression of these combinations requires careful attention to dosing and schedule to minimize these complications. Of the purine analogs in CLL, pentostatin appears to be least myelosuppressive. We have previously reported our experience with pentostatin and cyclophosphamide (PC regimen) in a cohort of heavily pretreated patients with CLL (JCO21:1278, 2003). We have since added rituximab to this active combination (PCR regimen) and have treated a second cohort of patients with CLL and other low grade B cell neoplasms. We now report on our cumulative experience of 69 patients (23 received PC and 46 received PCR) treated with pentostatin combination therapy.
The PC regimen consisted of pentostatin 4mg/m2 and cyclophosphamide 600mg/m2, given every 3 weeks for a total of 6 treatments. In the 2nd cohort of CLL patients, rituximab 375mg/m2 was added to this regimen starting with cycle 2. Supportive measures in both studies included hydration with each treatment (and monitoring of renal function) and prophylactic administration of filgrastim, sulfamethoxazole/trimethoprim, acyclovir, and antiemetics. In the first cohort of patients treated with the PC regimen, the median number of prior treatments was 3 (range 1–5) with the median age being 64 (32–77). There were responses achieved in 74% of patients with 17% complete responses seen in this heavily pretreated group. Similar (or perhaps slightly better) results were obtained with patients treated with the PCR regimen. For this cohort the median age was 62 (30–80) and the median number of prior regimens was 2 (1–7). Of the 32 patients with CLL 28 are evaluable for response: 79% responded and this includes 29% who achieved a complete response. Ten of the 14 patients with other low grade B cell diseases (SLL 8 patients, Waldenstrom’s macroglobulinemia 2 patients, follicular lymphoma 4 patients) are evaluable for response. The overall response rate for these patients was 50% (all PRs). These regimens were generally well tolerated with grade 3/4 toxicity consisting primarily of myelosuppression and its complications. We conclude that PC and PCR are highly active, well tolerated regimens even in heavily pretreated patients. We plan to conduct a multicenter study of PCR as initial therapy in patients with CLL.