Ripk3 signaling regulates HSCs during stress and represses radiation-induced leukemia in mice

Receptor-interacting protein kinase 3 (Ripk3) is one of the critical mediators of inflammatory cytokine-stimulated signaling. Here we show that Ripk3 signaling selectively regulates both the number and the function of hematopoietic stem cells (HSCs) during stress conditions. Ripk3 signaling is not required for normal homeostatic hematopoiesis. However, in response to serial transplantation, inactivation of Ripk3 signaling prevents stress-induced HSC exhaustion and functional HSC attenuation, while in response to fractionated low doses of ionizing radiation (IR), inactivation of Ripk3 signaling accelerates leukemia/lymphoma development. In both situations, Ripk3 signaling is primarily stimulated by tumor necrosis factor-α. Activated Ripk3 signaling promotes the elimination of HSCs during serial transplantation and pre-leukemia stem cells (pre-LSCs) during fractionated IR by inducing Mlkl-dependent necroptosis. Activated Ripk3 signaling also attenuates HSC functioning and represses a pre-LSC-to-LSC transformation by promoting Mlkl-independent senescence. Furthermore, we demonstrate that Ripk3 signaling induces senescence in HSCs and pre-LSCs by attenuating ISR-mediated mitochondrial quality control

Hyperoxemia and excess oxygen use in early acute respiratory distress syndrome : Insights from the LUNG SAFE study

Publisher Copyright: © 2020 The Author(s). Copyright: Copyright 2020 Elsevier B.V., All rights reserved.Background: Concerns exist regarding the prevalence and impact of unnecessary oxygen use in patients with acute respiratory distress syndrome (ARDS). We examined this issue in patients with ARDS enrolled in the Large observational study to UNderstand the Global impact of Severe Acute respiratory FailurE (LUNG SAFE) study. Methods: In this secondary analysis of the LUNG SAFE study, we wished to determine the prevalence and the outcomes associated with hyperoxemia on day 1, sustained hyperoxemia, and excessive oxygen use in patients with early ARDS. Patients who fulfilled criteria of ARDS on day 1 and day 2 of acute hypoxemic respiratory failure were categorized based on the presence of hyperoxemia (PaO2 > 100 mmHg) on day 1, sustained (i.e., present on day 1 and day 2) hyperoxemia, or excessive oxygen use (FIO2 ≥ 0.60 during hyperoxemia). Results: Of 2005 patients that met the inclusion criteria, 131 (6.5%) were hypoxemic (PaO2 < 55 mmHg), 607 (30%) had hyperoxemia on day 1, and 250 (12%) had sustained hyperoxemia. Excess FIO2 use occurred in 400 (66%) out of 607 patients with hyperoxemia. Excess FIO2 use decreased from day 1 to day 2 of ARDS, with most hyperoxemic patients on day 2 receiving relatively low FIO2. Multivariate analyses found no independent relationship between day 1 hyperoxemia, sustained hyperoxemia, or excess FIO2 use and adverse clinical outcomes. Mortality was 42% in patients with excess FIO2 use, compared to 39% in a propensity-matched sample of normoxemic (PaO2 55-100 mmHg) patients (P = 0.47). Conclusions: Hyperoxemia and excess oxygen use are both prevalent in early ARDS but are most often non-sustained. No relationship was found between hyperoxemia or excessive oxygen use and patient outcome in this cohort. Trial registration: LUNG-SAFE is registered with ClinicalTrials.gov, NCT02010073publishersversionPeer reviewe

Dependence of morphology on composition of poly(L-lactide)/poly(ethylene glycol) multiblock copolymers

International audienc

Synthesis and characterization of poly(L-lactide)-poly(ethylene glycol) multiblock copolymers

International audienc

HDAC1 is required for GATA-1 transcription activity, global chromatin occupancy and hematopoiesis

The activity of hematopoietic factor GATA-1 is modulated through p300/CBP-mediated acetylation and FOG-1 mediated indirect interaction with HDAC1/2 containing NuRD complex. Although GATA-1 acetylation is implicated in GATA-1 activation, the role of deacetylation is not studied. Here, we found that the FOG-1/NuRD does not deacetylate GATA-1. However, HDAC1/2 can directly bind and deacetylate GATA-1. Two arginine residues within the GATA-1 linker region mediates direct interaction with HDAC1. The arginine to alanine mutation (2RA) blocks GATA-1 deacetylation and fails to induce erythroid differentiation. Gene expression profiling and ChIP-seq analysis further demonstrate the importance of GATA-1 deacetylation for gene activation and chromatin recruitment. GATA-1(2RA) knock-in (KI) mice suffer mild anemia and thrombocytopenia with accumulation of immature erythrocytes and megakaryocytes in bone marrow and spleen. Single cell RNA-seq analysis of Lin(−) cKit(+) (LK) cells further reveal a profound change in cell subpopulations and signature gene expression patterns in HSC, myeloid progenitors, and erythroid/megakaryocyte clusters in KI mice. Thus, GATA-1 deacetylation and its interaction with HDAC1 modulates GATA-1 chromatin binding and transcriptional activity that control erythroid/megakaryocyte commitment and differentiation

HOTTIP lncRNA Promotes Hematopoietic Stem Cell Self-Renewal Leading to AML-like Disease in Mice

Long non-coding RNAs (lncRNAs) are critical for regulating HOX genes, aberration of which is a dominant mechanism for leukemic transformation. How HOX gene-associated lncRNAs regulate hematopoietic stem cell (HSC) function and contribute to leukemogenesis remains elusive. We found that HOTTIP is aberrantly activated in acute myeloid leukemia (AML) to alter HOXA-driven topologically associated domain (TAD) and gene expression. HOTTIP loss attenuates leukemogenesis of transplanted mice, while reactivation of HOTTIP restores leukemic TADs, transcription, and leukemogenesis in the CTCF-boundary-attenuated AML cells. Hottip aberration in mice abnormally promotes HSC self-renewal leading to AML-like disease by altering the homeotic/hematopoietic gene-associated chromatin signature and transcription program. Hottip aberration acts as an oncogenic event to perturb HSC function by reprogramming leukemic-associated chromatin and gene transcription. [Display omitted] •HOTTIP reprograms 3D AML genome and drives leukemic transcription profile in AML•HOTTIP binds and regulates genes important for hematopoiesis and leukemogenesis•HOTTIP KO attenuates AML progression by impairing leukemic transcription program•Hottip aberration perturbs HSC self-renewal leading to AML-like disease in mice Luo et al. find that the lncRNA HOTTIP is overexpressed in acute myeloid leukemia (AML). They show that HOTTIP coordinates topologically associated domain organization in the AML genome, including the posterior HOXA genes and various key hematopoietic regulator loci, and is important for AML growth

Transgenic Mice Expressing MCP-1 by the Urothelium Demonstrate Bladder Hypersensitivity, Pelvic Pain and Voiding Dysfunction: A Multidisciplinary Approach to the Study of Chronic Pelvic Pain Research Network Animal Model Study

<div><p>Monocyte chemoattractant protein-1 (MCP-1) is one of the key chemokines that play important roles in diverse inflammatory and chronic pain conditions. Interstitial cystitis/bladder pain syndrome (IC/BPS) is a chronic and debilitating inflammatory condition of the urinary bladder characterized by the hallmark symptoms of pelvic pain and voiding dysfunction. To facilitate IC/BPS research, we used transgenic technology to develop a novel urothelial MCP-1 secretion mouse model (URO-MCP-1). A transgene consisting of the uroplakin II gene promoter and the mouse MCP-1 coding sequence with a secretory element was constructed and microinjected. URO-MCP-1 mice were found to express MCP-1 mRNA in the bladder epithelium and MCP-1 protein in the urine, and developed bladder inflammation 24 hours after intravesical administration of a single sub-noxious dose of lipopolysaccharide (LPS). The inflamed bladders of URO-MCP-1 mice exhibited elevated mRNAs for interleukin (IL)-1ß, IL-6, substance P precursor, and nerve growth factor as well as increased macrophage infiltration. In parallel with these phenotypic changes, URO-MCP-1 mice manifested significant functional changes at days 1 and 3 after cystitis induction. These functional changes included pelvic pain as measured by von Frey filament stimulation and voiding dysfunction (increased urinary frequency, reduced average volume voided per micturition, and reduced maximum volume voided per micturition) as measured by micturition cages. Micturition changes remained evident at day 7 after cystitis induction, although these changes were not statistically significant. Control wild-type C57BL/6 mice manifested no clear changes in histological, biochemical and behavioral features after similar cystitis induction with LPS. Taken together, our results indicate that URO-MCP-1 mice are hypersensitive to bladder irritants such as LPS and develop pelvic pain and voiding dysfunction upon cystitis induction, providing a novel model for IC/BPS research.</p></div

Hoxblinc Is Aberrantly Expressed in Acute Myeloid Leukemia and Functions As a Potent Oncogenic Long Non-Coding RNA in Leukemogenesis

Abstract Aberrant expression of long non-coding RNAs (lncRNAs) might contribute to the development and progression of leukemia. However, functional studies on the actual role of lncRNAs during the development of leukemia remain scarce, and very few lncRNAs have been shown to be involved in leukemogenesis. HoxBlinc is an anterior HoxB gene-associated intergenic lncRNA. It is a cis-acting lncRNA and functions as an epigenetic regulator to coordinate anterior HoxB gene expression. Giving the dysregulation of HOXA/B genes is a dominant mechanism of leukemic transformation, HoxBlinc might be an oncogenic lncRNA of leukemia. To determine whether HOXBLINC lncRNA is aberrantly expressed in human AML samples, we performed RT-qPCR on bone marrow mononuclear cells (BMMNCs) from a cohort of 73 AML patients. A dramatic up-regulation of HOXBLINC was observed in over 60% of the patients. When TCGA-AML datasets of a cohort of 179 AML patients were analyzed for their HOXBLINC expression, a significant portion of these AML patients had high levels of HOXBLINC expression. Interestingly, AML patients with high HOXBLINC expression (the top thirty percentile of patients) had a significantly shortened survival as compared to patients with low HOXBLINC expression (the bottom thirty percentile). To investigate the impact of HoxBlinc overexpression on normal hematopoiesis and the pathogenesis of hematological malignancies in vivo, we generated a HoxBlinc transgenic(Tg) mouse model. Within 1 year of age, 67% of the HoxBlincTg mice (10 of 15) died or were sacrificed because of a moribund condition due to AML. We then assessed whether overexpression of HoxBlinc affects the pools of HSC/HPCs by flow cytometric analysis on the BM cells of young WT and HoxBlincTg mice (8-10 weeks of age). HoxBlincTg BM had a dramatically greater number of LT-HSC, ST-HSC, MPP cells, and a significantly higher percentage of GMP, but a lower percentage of MEP/CMP cell populations as compared to WT group. To determine the effect of HoxBlinc overexpression on the function of HSC/HPCs, we performed paired-daughter cell assay, replating assay and liquid culture on sorted LT-HSC, LSK or LK cells from young WT and HoxBlincTg mice, the results indicate that transgenic expression of HoxBlinc enhances HSC self-renewal and impairs HSC/HPC differentiation. To assess whether HoxBlinc overexpression-mediated changes in HSC/HPC function are cell-autonomous, we performed competitive transplantation assays to examine the repopulating capacity of HoxBlincTg BM cells. When the donor cell chimerism was analyzed kinetically in the PB of recipient mice, the CD45.2 cell population remained ~50% in mice receiving WT BM cells, whereas the CD45.2 chimerism in the recipients transplanted with HoxBlincTg BM cells steadily increased. Interestingly, mice receiving HoxBlincTg BM cells developed AML at 2-6 months after transplantation. Previous data reported that HoxBlinc can recruit the Setd1a/Mll1 histone H3K4 methyltransferase complex to mediate formation of the active topologically associated domain (TAD) in the anterior HoxB locus for transcription of the anterior HoxB genes. In this study, LSK or LK cells sorted from young WT and HoxBlincTg mice were analyzed by RNA-seq, ATAC-seq, H3K4me3 CHIP-seq and 4C analysis. Mechanistically, HoxBlinc overexpression alters HoxB locus chromatin three-dimensional organization to enhance enhancer/promoter chromatin accessibility and coordinate the expression of not only HoxB1-5 but also HoxA9, Runx1, Meis1 and so on, which are critical genes for HSC regulation and/or leukemogenesis. Our study provides novel insights into the HSC regulation by lncRNAs and identifies HOXBLINC, which coordinates to maintain an oncogenic transcription program for leukemic transformation, as a potent oncogenic lncRNA in leukemogenesis. Disclosures No relevant conflicts of interest to declare