bluuebunny/crossref_metadata_2025_split huggingface dataset:
Paracrine Bone Morphogenetic Protein Signaling in Iron Homeostasis
Authors: Babitt Jodie L. 
Published: November 2019

Iron is an essential nutrient that is required not only for hemoglobin production in red blood cells, but also as a co-factor of many other proteins that perform fundamental cellular processes. However, excess iron can generate free oxygen radicals that can be toxic. Cells and organisms have therefore evolved mechanisms to tightly control iron levels. Systemic iron homeostasis is governed by the iron hormone hepcidin that binds and degrades the iron exporter ferroportin to limit iron absorption from dietary sources and iron release from iron-recycling macrophages and hepatocyte stores. The key source of hepcidin that controls systemic iron homeostasis is the liver. Hepcidin production by the liver is coordinated by several signals that communicate the body's iron needs. Increases in serum and tissue iron induce hepcidin production, whereas iron deficiency suppresses hepcidin production, as feedback mechanisms to maintain steady state iron levels. Inflammation induces hepcidin to limit iron availability to infectious organisms that also require iron to grow and proliferate. Increases in erythropoietic drive suppress hepcidin production to increase iron availability for red blood cell production. The bone morphogenetic protein (BMP) signaling pathway is the central signal transduction pathway that controls hepcidin production in the liver. Activation of BMP signaling by iron loading or suppression of BMP signaling by iron deficiency or erythropoietic drive are key mechanisms by which these signals control hepcidin transcription. Iron loading increases production of BMP6 and BMP2 ligands by liver endothelial cells. Endothelial-derived BMP6 and BMP2 have paracrine actions on BMP receptors and the co-receptor hemojuvelin on hepatocytes to phosphorylate SMAD transcription factors, which translocate to the nucleus to regulate hepcidin transcription. Erythropoietic drive increases the production of erythroferrone by erythrocyte precursors. Erythroferrone is secreted into the circulation where it binds BMP ligands to prevent their interaction with cell surface receptors, thereby inhibiting hepcidin transcription. This talk will focus on recent insights into the molecular mechanisms by whch paracrine BMP signaling in the liver coordinates hepcidin production to regulate systemic iron homeostasis.

Disclosures
Babitt: Ferrumax Pharmaceuticals, Inc: Equity Ownership, Patents & Royalties; Keryx BIopharmaceuticals, Inc (now part of Akebia Therapeutics): Consultancy; Disc Medicine: Consultancy.
Proteostasis and Myeloid Stem Cell Production
Authors: Signer Robert 
Published: November 2019

Hematopoietic stem cells (HSCs) regenerate blood cells lost to turnover, injury and disease. Defects in HSC maintenance, such as those that occur during aging, lead to anemia, impaired immunity, and bone marrow failure. Over- or ectopic activation of HSC self-renewal programs leads to hematopoietic neoplasms. Thus, defects in HSC maintenance can lead to diverse malignant and non-malignant hematopoietic disorders. We recently discovered that HSCs have lower rates of protein synthesis than other blood cells. Low protein synthesis is necessary for HSCs, as genetic changes that increase protein synthesis impair HSC function. Importantly, this does not simply reflect HSC quiescence, as dividing HSCs also have lower rates of protein synthesis as compared to dividing restricted progenitors. However, why stem cells depend on low protein synthesis and how increases in protein synthesis impair stem cell function remain largely unknown. Translation is a key cog in both the gene expression and protein homeostasis (proteostasis) networks, and thus influences both the content and the quality of the proteome. We have now determined that low protein synthesis within HSCs is associated with elevated proteome quality in vivo. HSCs contain less ubiquitylated and unfolded proteins as compared to restricted myeloid progenitors, and modest increases in protein synthesis cause an accumulation of misfolded/unfolded proteins within HSCs. Thus, HSCs depend upon low protein synthesis to maintain proteome quality. To test how translational control of proteome quality affects stem cell function, we examined Aarssti/sti mice that harbor a mutation in the alanyl-tRNA synthetase, which causes a tRNA editing defect that increases amino acid misincorporation errors during translation. Aarssti/sti mice exhibit reduced HSC numbers and significantly diminished serial reconstituting activity in vivo, but do not exhibit defects within restricted progenitors. Surprisingly, a modest accumulation of misfolded/unfolded proteins does not induce significant activation of the unfolded protein response within HSCs, but instead overwhelms the capacity of the proteasome, which promotes the stabilization and increased abundance of c-Myc. Conditional deletion of a single copy of Myc is sufficient to significantly rescue serial reconstitution defects in Aarssti/sti HSCs. HSCs are thus dependent on low protein synthesis to maintain proteome quality and homeostasis to preserve their self-renewal activity in vivo.

Disclosures
No relevant conflicts of interest to declare.
Metabolic Control and Systems Immunology in Blood Cell Development
Authors: Chi Hongbo 
Published: November 2019

Coordination of metabolic programs with cell fate decisions is a fundamental determinant of hematopoietic cell development and function. Hematopoietic cells at different developmental and activation stages exhibit distinct metabolic signatures. Emerging evidence further highlights the interplay between cell signaling and metabolic programming in these processes. We found that myelopoiesis, including the differentiation of monocytes, macrophages and dendritic cells (DCs), required mechanistic target of rapamycin complex 1 (mTORC1) signaling and anabolic metabolism. Loss of mTORC1 impaired myelopoiesis under steady state and dampened innate immune responses against Listeria monocytogenes infection. Stimulation of hematopoietic progenitors with macrophage colony-stimulating factor (M-CSF) resulted in mTORC1-dependent anabolic metabolism, which in turn promoted expression of M-CSF receptor and transcription factors PU.1 and IRF8, thereby constituting a feed-forward loop for myelopoiesis. Mechanistically, mTORC1 engaged glucose metabolism and initiated a transcriptional program involving glycolysis and sterol biosynthesis after M-CSF stimulation. Integrative metabolomic and genomic profiling further identified one-carbon metabolism as a central node in mTORC1-dependent myelopoiesis. Moreover, we found that differentiation of DCs from bone marrow precursors was associated with dynamic regulation of mTORC1 signaling and cell metabolism. Either reduced or excessive mTORC1 activity was detrimental to DC development, associated with impaired regulation of cell metabolism. Interestingly, in contrast to the obligatory role of mTORC1 in monocyte and DC development, mTORC2 function was dispensable in these processes. Our results demonstrate that the interplay between mTORC1 signaling and bioenergetic and biosynthetic activities constitutes key metabolic checkpoints to orchestrate myelopoiesis. We are currently applying systems immunology approaches to explore metabolic signaling in myelopoiesis.

Disclosures
No relevant conflicts of interest to declare.
Understanding the Mechanisms Driving Genomic Instability in Adult T-Cell Leukemia/Lymphoma
Authors: Madireddy Advaitha , Barreto-Galvez Angelica , Ye B. Hilda 
Published: November 2019

Adult T-cell Leukemia/Lymphoma (ATLL) is a T-cell malignancy that results from infection by the retrovirus, human T cell lymphotropic virus-1 (HTLV-1). ATLL is endemic to Japan, the Caribbean regions and Latin America. Despite the rare occurrence of the disease, ATLL is a very aggressive malignancy with limited treatment options. Recent studies show that the ATLL patients diagnosed in North America (NA-ATLL), who are largely from the Caribbean region, have extremely poor prognosis as compared to the Japanese ATLL (J-ATLL) patients. A better understanding of the molecular pathogenesis of NA-ATLL is critical to identifying effective treatment measures for these patients. It has been previously shown that genomic instability including extensive chromosomal variations can be frequently found in ATLLs. However, the underlying mechanisms leading to this instability are unclear. Analysis of the mechanism of HTLV-1 action has revealed that the virus, in addition to hijacking the host cell machinery, disrupts DNA repair mechanisms and cell division processes. While the disruption of repair mechanisms could be held accountable for the accumulation of damage in ATLL cells, the precise nature of this disruption has not been fully understood. In proliferating cells, damage to the DNA occurs or is primarily recognized during DNA replication. This indicates that defective DNA replication could be an important factor driving genomic instability in ATLL cells. Possible involvement of replicative defects in the etiology of ATLL is further strengthened by the fact that genomic instability in ATLL cells has been shown to occur at difficult to replicate genomic regions referred to as common fragile sites. Here, using a powerful locus specific approach called the single molecule analysis of replicated DNA (SMARD), we show that perturbed DNA replication is an inherent component of disease manifestation in ATLL patients. Furthermore, our preliminary findings suggest that these changes in DNA replication can be largely attributed to the EP300 inactivating mutations often found among NA-ATLL patients. This study will help elucidate the molecular mechanisms contributing to the marked chemo-resistant feature of NA-ATLL patients, as compared to J-ATLL patients. In addition to increasing our understanding of the mechanisms contributing to ATLL in general, the results from this study may inform new and mechanism-based treatment paradigms that target the replicative defects of this unique disease.

Disclosures
No relevant conflicts of interest to declare.
The Effects of Text Messaging for Promoting the Retention of the First-Time Blood Donors, a Randomized Controlled Study (TEXT study)
Authors: Pongsananurak Chontara , Norasetthada Lalita , Tantiworawit Adisak , Rattarittamrong Ekarat , Rattanathammethee Thanawat , Sriwichai Maitree , Leetrakool Nipapan , Piriyakhuntorn Pokpong , Hantrakool Sasinee , Chai-Adisaksopha Chatree 
Published: November 2019

Introduction
Recruiting blood donors remains a challenging process to ensure sufficient blood product supplies. There were several interventions implemented in order to promote the retention of first-time donors, including short messaging service (SMS). However, the efficacy of SMS for promoting the retention of blood donation has never been demonstrated in a randomized controlled trial. Here, we report the interim analysis of the TEXT study.
Methods
This is a single center, randomized- controlled trial. We enrolled participants 18 years of age or older who were first-time blood donors and who were able to read and understand text messages. Participants were excluded if the purposes of blood donation were as follows, autologous donation, apheresis or blood letting. Participants were also excluded if they had no cell phone number or lived temporarily in the area. Participants were randomized within 24 hours followed the blood donation in a 1:1 ratio (text group vs control group). Only participants who were allocated in the "text group'' would receive a computer-generated text message once his/her blood product was dispatched from the transfusion service. The content of text message was "We would like to inform you that your blood has been used for patients on DD.MM.YYYY. Because of your blood donation, patients' lives will be saved." The primary outcome of the study was the rate of returning for the second donation at 6 months. Odds ratio (OR) and 95% confidence interval (CI) for retention rate was calculated based-on a modified intention-to-treat analysis.
Results
In a modified intention-to-treat analysis, there were 867 participants allocated to the text group and 864 participants to the control group (Figure 1). Mean age was 26.1 (standard deviation, SD 9.2) and 26.2 (SD 9.4) years, respectively. The primary outcome occurred in 120 of 867 (13.8%) in the text group and 89 of 864 (10.3%) in the control group, OR 1.40 (95%CI 1.04 to 1.87, P-value=0.02). Number needed to treat was 29. Figure 2 demonstrates the Kaplan-Meier curves of participants who returned for the second blood donation comparing between text and control groups. The median time for returning was 119 days (interquartile range, 95.5-150.5) in text group and 119 days (interquartile range, 98-148) in control group. Subgroup analysis does not show significant interactions between participants' characteristics and outcome.
Conclusion
Among first-time blood donors, text messaging after blood product being dispatched is a simple, inexpensive and effective intervention to increase the retention rate for second donation at 6 months duration.

Disclosures
No relevant conflicts of interest to declare.
Glycosylationof Immunoglobulins Determine Bone Loss in Multiple Myeloma
Authors: Westhrin Marita , Kovcic Vlado , Bondt Albert , Holst Stephanie , Zhang Zejian , Sundan Anders , Slørdahl Tobias S. , Waage Anders , Wuhrer Manfred , Standal Therese 
Published: November 2019

About 80% of patients with multiple myeloma develop a severe osteolytic bone disease causing pain and fractures. The myeloma cells secrete immunoglobulins and the presence of monoclonal immunoglobulins in serum is a hallmark of the disease. Immunoglobulins play a role in bone loss, but have not been linked with the bone disease in multiple myeloma.
In this work, we isolated immunoglobulins from serum of myeloma patients using protein G coupled magnetic beads and columns. We found that immunoglobulins from patients with bone disease (n=16) promoted osteoclast differentiation when added to human monocyte-derived pre-osteoclasts (p=0.006). We next fractionated the immunoglobulin samples by size-exclusion chromatography and found that the "osteoclast promoting activity" was in the high-molecular weight fractions, suggesting that they are in complexes. Since extent of complex formation may be determined by glycosylation, we examined whether there is a difference in immunoglobulin glycosylation between healthy controls and patients, and whether it changes during disease progression. To this end we analysed IgG glycosylation in serum samples from patients (n=72) and age and sex matched controls (n=51). These analyses showed that patient IgG was less galactosylated (p=0.02) and less sialylated (p=0.04) compared with control IgG. Moreover, patients with bone disease (n=43) had significantly less galactose on IgG compared with patients without bone disease (p=0.02, n=33). Supporting this data, we found that galactosidase treatment of immunoglobulins from patients without bone disease induced osteoclastogenesis (p=0.03), whereas addition of galactose to immunoglobulins of patients with bone disease removed their pro-osteoclastogenic effect (p=0.01). Further, the glycosyltransferases ST6GAL1 and B4GALT11, which add sialic acid and galactose to the sugar chain, respectively, are less expressed in plasma cells obtained from patients with bone disease (n=137) compared with those without (n=36, p<0.002, p<0.001, GSE755). Importantly, we observed a significant reduction of IgG glycosylation (p=0.02, n=8) in serum samples obtained from individual patients before and after the onset of bone disease.
Taken together, our data support that immunoglobulins promote bone loss in multiple myeloma.

Disclosures
No relevant conflicts of interest to declare.
"Identification of Mechanisms By Which Mesenchymal Stem/Stromal Cells Contribute to Acute Myeloid Leukemia"
Authors: Aldreiwish Allolo , Muradia Gauri , Gagne Remi , Beal Marc , Yauk Carole , Allan David S. , Diaz de la Guardia Rafael , Menendez Pablo , Rosu-Myles Michael , Lavoie Jessie .R. 
Published: November 2019

Acute myeloid leukemia (AML) is a blood malignancy resulting in abnormal hematopoiesis that is reported to be associated with alterations in the bone marrow microenvironment (BME). Current treatments for this heterogeneous disease, which target the leukemic cells but not the BME, are largely unsuccessful for the majority of AML subtypes. By better understanding the mechanisms by which the BME contributes to leukemogenesis, it may be possible to introduce more effective treatments for AML.
Mesenchymal stem cells (MSCs) are an essential component of the BME that have been shown to support normal hematopoiesis. Therefore, MSCs may have several roles in the alteration of the BME, leukemogenesis, and AML relapse and can provide an excellent model for studying the BME in vitro. While some studies have characterized AML-derived MSCs (AML-MSCs), their exact role in the disease remains unclear. Our RNAseq analysis of AML-MSCs (n=30), and healthy donor MSCs (HD-MSCs) (n=8) identified that, among 7655 genes, 21 genes were significantly differentially expressed in AML-MSCs. Through in silico analysis of this gene set, genes of interest were identified as having the potential to directly alter the BME and affect AML pathogenesis through BMP/TGF-β pathways.
Current work is focusing on investigation of the effects of selected genes with biological relevance on MSCs intrinsic and extrinsic functional properties. This study will improve our understanding of the role of MSCs in AML BME and help in the discovery of new therapeutic targets.

Disclosures
No relevant conflicts of interest to declare.
A Review of Inappropriate D-Dimer Ordering at a Canadian Tertiary Care Centre
Authors: Oliver Monika , Karkhaneh Mohammad , Karathra Jacqueline , Goubran Mariam , Wu Cynthia M. 
Published: November 2019

Introduction
The D-dimer has been validated for use in the diagnosis of venous thromboembolism (VTE). The high sensitivity of the assay allows for safe exclusion of VTE in patients with low pre-test probability. Pre-test probability scores such as the Wells score for Deep Vein Thrombosis (DVT) and Pulmonary Embolism (PE) have been established to help guide physicians on when to order a D-dimer in patients with suspected VTE.
We sought to explore the landscape of D-dimer ordering at our institution and what clinical circumstances trigger D-dimer ordering.
Methods
We conducted a retrospective chart review of 237 patients in whom a D-dimer has been ordered over a 3-month period from January to March 2018 at the University of Alberta Hospital, Edmonton, Canada. Charts were reviewed for the following parameters: Specialty of ordering physician, apparent indication for ordering, patient risk factors for VTE and evidence of pre-test probability calculation. If no pre-test probability was recorded, we retrospectively calculated Wells DVT or PE scores depending on the apparent indication. We then reviewed subsequent investigations thought to be influenced by interpretation of the D-dimer. These included ventilation/perfusion scans (V/Q scan), ultrasound Doppler studies and Computerized Tomography pulmonary angiography (CTPA).
Results
Of the 237 charts reviewed, 84.4% of D-dimers were ordered in the Emergency Department while only 14.3% were drawn on admitted patients. Sixty-nine percent of the patients were identified as having at least one risk factor for the development of VTE with prolonged hospitalization (5.5%) and personal history of VTE (4.2%) being the most common. Indication for ordering was suspected VTE in 76.3% of patients while the indications was unclear in 12.7% of patients. An initial pre-test probability score was recorded for only 3 patients. Of the D-dimers ordered, 47.7% were above the upper limit of normal (≥ 0.50 mg/L) and considered a positive test. Forty five CTPAs and 27 V/Q scans were performed with only 4 (1.69%) and 6 (2.53%) confirming the presence of pulmonary emboli, respectively. Doppler ultrasounds were performed on 18 patients (7.6%) with only one confirming a DVT.
Conclusions
Our data shows that the majority of physicians at our institution fail to utilize pre-test probability tools prior to ordering a D-dimer. This leads to unnecessary costs, overuse of imaging studies and results in low rates of positive scans.

Disclosures
Wu: Bayer: Other: Local PI for trial ; BMS-Pfizer: Other: Local PI for trial ; Daiichi-Sankyo: Other: Local PI for trial .
Increased Thromboxane in Patients with Polycythemia Vera and Thrombosis: Evidence for Aspirin-Unsuppressible Platelet Activation In Vivo
Authors: Cacciola Rossella Rosari , Gentilini Cacciola Elio , Vecchio Veronica , Cacciola Emma 
Published: November 2019

Polycyhemia vera (PV) is a myeloproliferative neoplasm characterized by increased thromboxane (TX) production and thrombotic risk. It is reported that serum TXB2 concentrations in PV patients are twofold higher than healthy controls and that low-dose aspirin (ASA) therapy reduces the risk of major vascular events by 50 to 60%. To evaluate this unusual size of the effect of ASA we have studied platelet count, hematocrit (HCT), β-thromboglobulin (β-TG) and platelet factor 4 (PF4), as markers of platelet activation, TXB2, as primary indicator of platelet activation, the platelet function activity (PFA), as indicator of ASA platelet sensitivity, and the clotting time (CT), as parameter of thrombin formation. We studied 60 patients (38 men, 22 women; mean age 51 years, range 32-70) with PV according to WHO criteria. The mean duration of disease was 12 years. All patients were on ASA 100 mg once daily. All patients were on phlebotomy. None had inherited or acquired thrombotic risk factors. Of 60 patients, 30 had thrombosis (20 men, 10 women) and 30 had no thrombosis. Of 30 with thrombosis, 15 developed nonfatal myocardial infarction (10 men, 5 women) defined by chest pain of typical intensity and duration and ST-segment elevation in any limb lead on electrocardiography, 10 had nonfatal stroke (8 men, 2 women) confirmed with the use of magnetic resonance imaging, and 5 (2 men , 3 women) had deep venous thrombosis confirmed by ultrasonography. Platelet count and HCT were measured by automated analyzer. β-TG and PF4 were determined by ELISA. TXB2 was measured by radioimmunoassay technique. ASA platelet sensitivity was measured by Platelet Function Analyzer (PFA-100). CT was measured by thromboelastometry. The mean platelet count was 430±170x109/L. The mean HCT value was 42±3%. The patients with thrombosis had high β-TG, PF4 and TXB2 (110±45 IU/ml, 45±21 IU/ml, and 1.700±1.990 nmol/L, respectively), shortened C/EPI closure time (T, unit: s, n.v. 84-160 s) (55±10 s) and shortened CT (CT, unit: s. n.v. 100-240 s) (45±20 s) whereas the patients without thrombosis had normal β-TG, PF4 and TXB2 (20±11 IU/ml, 6±2 IU/ml, and 800±280 nmpl/L, respectively), prolonged C/EPI closure time (249±40 s) and normal CT (110±20 s). These findings might suggest that in PV patients and thrombotic complications might need a platelet-selective dosage of ASA.

Disclosures
No relevant conflicts of interest to declare.