SRSF2 Is Essential For Hematopoiesis and Its Mutations Dysregulate Alternative RNA Splicing In MDS

Abstract Myelodysplastic syndromes (MDS) are a group of neoplasms that are ineffective in generating multiple lineages of myeloid cells and have various risks to progress to acute myeloid leukemia. Recent genome-wide sequencing studies reveal that mutations in genes of splicing factors are commonly associated with MDS. However, the importance of these splicing factors in hematopoiesis has been unclear and the causal effect of their mutations on MDS development remains to be determined. One of these newly identified genes is SRSF2, and its mutations have been linked to poor survival among MDS patients. Interestingly, most of SRSF2 mutations occur at proline 95 and the majority of these mutations change this proline to histidine (P95H). Given that SRSF2 is a well-characterized splicing factor involved in both constitutive and regulated splicing, we hypothesize that SRSF2 plays an important role in normal hematopoiesis and the SRSF2 mutations induce specific changes in alternative splicing that favor disease progression. We first examined the role of SRSF2 in hematopoiesis by generating Srsf2 null mutation in mouse blood cells via crossing conditional Srsf2 knockout mice (Srsf2f/f) with blood cell-specific Cre transgenic mice (Vav-Cre). The mutant mice produced significantly fewer definitive blood cells (10% of wild type controls), exhibited increased apoptosis in the remaining blood cells, and died during embryonic development. Importantly, we detected no hematopoietic stem/progenitor cells (lineage-/cKit+) in E14 fetal livers of Vav-Cre/Srsf2f/f mice. These results indicate that SRSF2 is essential for hematopoiesis during embryonic development. We next examined the role of SRSF2 in adult hematopoiesis by injecting polyIC into mice that carry a polyIC inducible Cre expression unit. Unexpectedly, after multiple polyIC treatments, the Srsf2f/f mice stayed alive during several months of observation. Time course genotyping analyses of polyIC treated mice revealed an increased rate of incomplete Srsf2 deletion in peripheral blood cells. These observations suggest that Srsf2 ablation did not cause immediate cell lethality in differentiated blood cells, but the gene is indispensable for the function of blood stem/progenitor cells. Since mutations of splicing factors are generally heterozygous in MDS patients, we also examined mice with Srsf2+/- blood cells. No obvious defect of hematopoiesis was observed under normal conditions or in response to stress with 5-FU treatment and sublethal irradiation. To gain molecular insight into the splicing activity of MDS-associated mutant forms of SRSF2, we performed large-scale alternative splicing surveys by using RNA-mediated oligonucleotide annealing, selection, and ligation coupled with next-generation sequencing (RASL-seq) previously developed in our lab, which offers a robust and cost-effective platform for splicing profiling. Compared to vector transduction controls, we found that overexpression of both wild type and P95H SRSF2 induced many, but distinct changes in alternative splicing in lineage-negative bone marrow cells, and importantly, we noted several changes in genes with known roles in hematopoietic malignancies that were uniquely induced by the mutant SRSF2. To further link the mutations to altered splicing in MDS patients, we also applied RASL-seq to a large number of MDS patient samples with or without mutations in SRSF2 or other splicing regulators. The data revealed a specific set of alternative splicing events that are commonly linked to MDS with splicing factor mutations. These findings strongly suggest that many of these mutations in splicing regulators are gain-of-function mutations that are causal to MDS. In conclusion, we report that SRSF2 plays an essential role in hematopoietic stem/progenitor cells and that the MDS-associated mutations in SRSF2 have a dominant effect on RNA alternative splicing. These findings provide functional information and molecular basis of SRSF2 and its MDS-related mutations in hematopoiesis and related clinical disorders. Disclosures: No relevant conflicts of interest to declare

Early and Differential Diagnosis of Dementia and Mild Cognitive Impairment Design and Cohort Baseline Characteristics of the German Dementia Competence Network

Background: The German Dementia Competence Network (DCN) has established procedures for standardized multicenter acquisition of clinical, biological and imaging data, for centralized data management, and for the evaluation of new treatments. Methods: A longitudinal cohort study was set up for patients with mild cognitive impairment (MCI), patients with mild dementia and control subjects. The aims were to establish the diagnostic, differential diagnostic and prognostic power of a range of clinical, laboratory and imaging methods. Furthermore, 2 clinical trials were conducted with patients suffering from MCI and mild to moderate Alzheimer's Disease (AD). These trials aimed at evaluating the efficacy and safety of the combination of galantamine and memantine versus galantamine alone. Results: Here, we report on the scope and projects of the DCN, the methods that were employed, the composition and flow within the diverse groups of patients and control persons and on the clinical and neuropsychological baseline characteristics of the group of 2,113 subjects who participated in the observational and clinical trials. Conclusion: These data have an impact on the procedures for the early and differential clinical diagnosis of dementias, the current standard treatment of AD as well as on future clinical trials in AD. Copyright (C) 2009 S. Karger AG, Base

A comparative analysis of Dmc1 and Rad51 nucleoprotein filaments

filament

READING and FEELING: the effects of a literature-based intervention designed to increase emotional competence in second and third graders

Emotional competence has an important influence on development in school. We hypothesized that reading and discussing children’s books with emotional content increases children’s emotional competence. To examine this assumption, we developed a literature-based intervention, named READING and FEELING, and tested it on 104 second and third graders in their after-school care center. Children who attended the same care center but did not participate in the emotion-centered literary program formed the control group (N = 104). Our goal was to promote emotional competence and to evaluate the effectiveness of the READING and FEELING program. Emotional competence variables were measured prior to the intervention and nine weeks later, at the end of the program. Results revealed significant improvements in the emotional vocabulary, explicit emotional knowledge, and recognition of masked feelings. Regarding the treatment effect for detecting masked feelings, we found that boys benefited significantly more than girls. These findings underscore the assumption that children’s literature is an appropriate vehicle to support the development of emotional competence in middle childhood

Evaluating Depressive Symptoms in Schizophrenia: A Psychometric Comparison of the Calgary Depression Scale for Schizophrenia and the Hamilton Depression Rating Scale

Background: The aim of this study was to compare two measures of depression in patients with schizophrenia and schizophrenia spectrum disorder, including patients with delusional and schizoaffective disorder, to conclude implications for their application. Sampling and Methods: A total of 278 patients were assessed using the Calgary Depression Scale for Schizophrenia (CDSS) and the Hamilton Depression Rating Scale (HAMD-17). The Positive and Negative Syndrome Scale (PANSS) was also applied. At admission and discharge, a principal component analysis was performed with each depression scale. The two depression rating scales were furthermore compared using correlation and regression analyses. Results: Three factors were revealed for the CDSS and HAMD-17 factor component analysis. A very similar item loading was found for the CDSS at admission and discharge, whereas results of the loadings of the HAMD-17 items were less stable. The first two factors of the CDSS revealed correlations with positive, negative and general psychopathology. In contrast, multiple significant correlations were found for the HAMD-17 factors and the PANSS sub-scores. Multiple regression analyses demonstrated that the HAMD-17 accounted more for the positive and negative symptom domains than the CDSS. Conclusions:The present results suggest that compared to the HAMD-17, the CDSS is a more specific instrument to measure depressive symptoms in schizophrenia and schizophrenia spectrum disorder, especially in acutely ill patients. Copyright (c) 2012 S. Karger AG, Base

Моделирование особенностей движения геохода с ножевым исполнительным органом

Objective. To evaluate depressive symptoms regarding their association with the acute outcome in first-episode schizophrenia comparing risperidone and haloperidol. Method. A total of 274 patients were analysed within a double-blind randomized controlled trial and treated with risperidone or haloperidol. The patients were grouped according to their baseline HAMD-21 total score in a "depressed" (HAMD-21 >= 16) or "non-depressed" (HAMD-21 < 16) patient subgroup. PANSS, HAMD-21, GAF, SOFAS and AIMS ratings were performed. Early response was defined as an initial 20% reduction of the PANSS total score from admission to week 2, response as an at least 50% reduction of the PANSS total score from admission to discharge and remission according to the consensus criteria. Results. A total of 124 patients were classified as depressive at baseline with 22 patients still being depressive at discharge. The depressed and non-depressed patients did not significantly differ regarding the treatment with risperidone and haloperidol (P = 0.2270). The depressive patients suffered from significantly more suicidal tendencies (P = 0.0165), had significantly less insight into their illness (P = 0.0152) and featured significantly worse functioning (P = 0.0066). Patients with depressive symptoms achieved remission significantly less often than non-depressed patients. Conclusion. The importance of a specific and adequate treatment of depressive symptoms is highlighted

Genetic Deletion of SEPT7 Reveals a Cell Type-Specific Role of Septins in Microtubule Destabilization for the Completion of Cytokinesis

Cytokinesis terminates mitosis, resulting in separation of the two sister cells. Septins, a conserved family of GTP-binding cytoskeletal proteins, are an absolute requirement for cytokinesis in budding yeast. We demonstrate that septin-dependence of mammalian cytokinesis differs greatly between cell types: genetic loss of the pivotal septin subunit SEPT7 in vivo reveals that septins are indispensable for cytokinesis in fibroblasts, but expendable in cells of the hematopoietic system. SEPT7-deficient mouse embryos fail to gastrulate, and septin-deficient fibroblasts exhibit pleiotropic defects in the major cytokinetic machinery, including hyperacetylation/stabilization of microtubules and stalled midbody abscission, leading to constitutive multinucleation. We identified the microtubule depolymerizing protein stathmin as a key molecule aiding in septin-independent cytokinesis, demonstrated that stathmin supplementation is sufficient to override cytokinesis failure in SEPT7-null fibroblasts, and that knockdown of stathmin makes proliferation of a hematopoietic cell line sensitive to the septin inhibitor forchlorfenuron. Identification of septin-independent cytokinesis in the hematopoietic system could serve as a key to identify solid tumor-specific molecular targets for inhibition of cell proliferation

A novel prognostic risk model for patients with refractory/relapsed acute myeloid leukemia receiving venetoclax plus hypomethylating agents

Off-label hypomethylating agents and venetoclax (HMA/VEN) are often used for relapsed and refractory (R/R) AML patients. However, predictors of outcome are elusive. The objective of the current retrospective observational multicenter study of 240 adult patients (median age 68.6 years) with R/R AML was to establish a prognostic risk score. Overall response was documented in 106 (44%) patients. With a median follow-up of 31.5 months, 179 deaths were recorded. Median overall survival (mOS) was 7.9 months. In multivariate analysis of the subgroup with molecular information (n = 174), risk factors for inferior survival included the presence of extramedullary disease, HMA pretreatment and mutations in NF1, PTPN11, FLT3, and TP53, whereas mutated SF3B1 was identified as favorable risk factor. These risk factors were subsequently applied to construct an HR-weighted risk model that allocated patients to one of three risk groups with significantly different survival outcomes: favorable (n = 46; mOS 21.4 months), intermediate (n = 75; mOS 7.5 months), and adverse (n = 53; mOS 4.6 months; p < 0.001). The model was validated in 189 AML patients treated with HMA/VEN in first line. This clinical-molecular, 3-tiered venetoclax prognostic risk score (VEN-PRS) for HMA/VEN treatment outcomes in R/R AML patients will support the selection of appropriate treatment options in this high-risk population

Impact of axial active magnetic bearing stiffness coefficient on resonance frequencies of reaction wheel rotor

Разработана математическая модель системы «ротор - электромагнитные подшипники» для электродвигателя-маховика системы ориентации и стабилизации космического аппарата. Модель учитывает собственные частоты изгибных колебаний ротора и коэффициенты жесткости электромагнитных подшипников. Предложен способ повышения угловой жесткости системы путем применения многополюсного осевого электромагнитного подшипника и рассмотрено влияние его коэффициента жесткости на собственные частоты системы.The paper presents the mathematical model of «rotor - active magnetic bearings» system for reaction wheel used in spacecraft attitude control system. Developed model consider the natural frequencies of rotor bending oscillations and stiffness parameters of electromagnetic bearing. Method of angular stiffness increasing by using multipolar axial magnetic bearing is suggested and the results of impact analysis of multipolar axial magnetic bearing stiffness on resonance frequencies of system is considered

Cell‐freeDNAfor detection and monitoring of extramedullary AML relapse

Isolated extramedullary manifestations (IEM) of acute myeloid leukemia (AML) are recurrent events, especially following allogeneic hematopoietic cell transplantation (alloHCT). To date, measurable residual disease (MRD) assessment for this difficult-to-treat patient cohort has not been established. In this study, we evaluated highly sensitive next-generation sequencing (NGS) of IEM-AML tumor and compared it with cell-free DNA (cfDNA) from plasma, as well as highly sensitive NGS analysis of bone marrow mononuclear cells (BMMC) and peripheral blood mononuclear cells (PBMC), in a cohort of 15 IEM-AML patients with 19 IEM-AML episodes. cfDNA demonstrated a superior representation of IEM-AML tumor mutations compared to BMMC or PBMC, with a median variant allele frequency (VAF) of 0.8% and a mutation detection rate of 62% (37 of 60 mutations), compared to a median VAF of 0.05% and detection rate of 27%, respectively (16 of 60 mutations, p < 0.01). Among 44 mutations identified in 14 IEM-AML relapse tumors, 30 mutations (68%) were known from initial diagnosis. Using diagnostic mutations from initial diagnosis for MRD analysis and detection of IEM-AML relapse, 16 of 17 IEM-AML relapse episodes were detected via cfDNA, whereas only 7 of 17 were identified using conventional analysis of BMMC or PBMC. Our findings demonstrate that cfDNA analysis from plasma effectively captures the molecular profile of IEM-AML. More than one-third of clinically relevant mutations were exclusively detected through cfDNA and were missed by conventional NGS-MRD of BMMC or PBMC. These results suggest that MRD monitoring using cfDNA offers a more comprehensive and sensitive approach to detecting IEM-AML relapse compared to standard methods