The Cloning of Erythropoiesis-related Genes with the Innovated Model System

Most studies of erythropoiesis have been performed either with the virally transformed MEL cells or with the scarce erythroblasts within unhomogeneous cell populations.MEL cells are the Friend virus transformed mouse erythroleukemia cells and have lost the capacity to respond to erythropoietin.Moreover,the research in the field of erythropoiesis has been severely hampered by the paucity of erythroblasts obtained from chick embryos,human,mouse,rat fetal liver,mouse spleen,or the bone marrow.In our paper,the fetal blood from newly slaughtered pregnant sheep meets the needs of studies as abundant staring biological materials at the nucleotide level and also reflects in vivo proliferative and differential status of erythroblasts.Appling the technique of mRNA differential display with minor modification,we directly compared cDNA fragmerts from the fetal blood erythroblasts and adult pregnant sheep leukocytes by PCR on DNA sequencing gels and revealed two differentially expressing bands.One is a novel gene fragment, which has homology with UV-sensitive cone opsin or rhodopsin by examinating the predicted amino acid sequence.Since the blood cells are sensitive to radiation,it can be safely inferred that this fragment participate in the process of cytocidal effect of the radiation.The other fragment is glucose induced gene /elongation factor 2 3′end noncoding region,which was first cloned from glucose induced bovine aortic smooth muscle cells.Using Northern blot hybridization method,authentic specific expression was confirmed.

Y Specific Sequence Gene Analysis of Single Fetal Nucleated Erythroblasts from the Peripheral Blood of Pregnant Women

The single cell isolation technique was used to detect fetal nucleated erythroblasts at a single cell level from the peripheral blood of pregnant women in order to investigate the feasibility of this method for noninvasive prenatal diagnosis. Single fetal nucleated erythroblasts were isolated from the peripheral blood samples from 51 pregnant women by micromanipulation techniques after density gradient centrifugation. Nested polymerase chain reaction method was used to amplify the SRY gene. It was found that the concordance rate of amplification results with real fetal sex was 82.61 %. The sensitivity and specificity were 80 % and 87.50 % respectively. It was suggested that it is feasible and promising in non invasive prenatal diagnosis to detect fetal nucleated erythroblasts at a single cell level by using micromanipulation techniques.

Severe Anaemia during Natalizumab Treatment: Case Presentation with Literature Review

Progressive multifocal leukoencephalopathy is the most common serious complication related to natalizumab. However, serious haematological complications are very uncommon during treatment with natalizumab. Here we reported the case of an 18-year-old man with a 4-year history of relapsing-re- mitting multiple sclerosis. He was treated firstly by Teriflunomide for 1 year, but he presented relapses and his MRI shows new contrast-enhancing lesions. Therefore, we decided to switch from Teriflunomide to Natalizumab. The patient presented with profound anaemia after the 16th infusions treatment with Natalizumab. The patient’s hemoglobin was 3.2 g/dL with a lower blood reticulocyte value. After red cell transfusions and cessation of Natalizumab, anaemia resolved. Natalizumab was changed by an anti-CD20 monoclonal antibody. The patient had a stable course of multiple sclerosis at 13 months after initiation of Rituximab. We should alert clinicians to be aware of the possibility of anaemia during treatment by Natalizumab.

The non-canonical poly(A)polymerase FAM46C promotes erythropoiesis

The post-transcriptional regulation of mRNA is a crucial component of gene expression.The disruption of this process has detrimental effects on the normal development and gives rise to various diseases.Searching for novel post-transcriptional regulators and exploring their roles are essential for understanding development and disease.Through a multimodal analysis of red blood cell trait genome-wide association studies(GWAS)and transcriptomes of erythropoiesis,we identify FAM46C,a non-canonical RNA poly(A)polymerase,as a necessary factor for proper red blood cell development.FAM46C is highly expressed in the late stages of the erythroid lineage,and its developmental upregulation is controlled by an erythroidspecific enhancer.We demonstrate that FAM46C stabilizes mRNA and regulates erythroid differentiation in a polymerase activity-dependent manner.Furthermore,we identify transcripts of lysosome and mitochondria components as highly confident in vivo targets of FAM46C,which aligns with the need of maturing red blood cells for substantial clearance of organelles and maintenance of cellular redox homeostasis.In conclusion,our study unveils a unique role of FAM46C in positively regulating lysosome and mitochondria components,thereby promoting erythropoiesis.

Vagal-mAChR4 signaling promotes Friend virus complex(FV)-induced acute erythroleukemia

Erythroleukemia belongs to acute myeloid leukemia(AML)type 6(M6),and treatment remains difficult due to the poor prognosis of the disease.Friend virus(FV)is a complex of two viruses:Friend murine leukemia virus(F-MuLV)strain along with a defective spleen focus-forming virus(SFFV),which can induce acute eryth-roleukemia in mice.We have previously reported that activation of vagalα7 nicotinic acetylcholine receptor(nAChR)signaling promotes HIV-1 transcription.Whether vagal muscarinic signaling mediates FV-induced erythroleukemia and the underlying mechanisms remain unclear.In this study,sham and vagotomized mice were intraperitoneally injected with FV.FV infection caused anemia in sham mice,and vagotomy reversed this change.FV infection increased erythroblasts ProE,EryA,and EryB cells in the spleen,and these changes were blocked by vagotomy.In bone marrow,FV infection reduced EryC cells in sham mice,an effect that was coun-teracted by vagotomy.FV infection increased choline acetyltransferase(ChAT)expression in splenic CD4^(+)and CD8þT cells,and this change was reversed by vagotomy.Furthermore,the increase of EryA and EryB cells in spleen of FV-infected wild-type mice was reversed after deletion of ChAT in CD4^(+)T cells.In bone marrow,FV infection reduced EryB and EryC cells in sham mice,whereas lack of ChAT in CD4^(+)T cells did not affect this change.Activation of muscarinic acetylcholine receptor 4(mAChR4)by clozapine N-oxide(CNO)significantly increased EryB in the spleen but decreased the EryC cell population in the bone marrow of FV-infected mice.Thus,vagal-mAChR4 signaling in the spleen and bone marrow synergistically promotes the pathogenesis of acute erythroleukemia.We uncover an unrecognized mechanism of neuromodulation in erythroleukemia.

Erythroblast island macrophages: recent discovery and future perspectives

Erythroblastic island(EBI),composed of a central macrophage surrounded by developing erythroid cells,is a structure found in hematopoietic tissues such as fetal liver and bone marrow.It is the first described hematopoietic niche that predominantly supports erythropoiesis.Although it is well accepted that EBIs and EBI macrophage play important roles during erythropoiesis,the mechanisms by which they support erythropoiesis remain largely unclear due to our inability to identify and isolate EBI macrophages.Earlier efforts to identify surface markers for EBI macrophages have focused on the adhesion molecules which are involved in macrophage’s interaction with erythroblasts.These include EMP,Vcam1,CD169,CD163,and aV integrin.Findings from these earlier studies suggested that combination of Vcam1,CD169,and mouse macrophage surface marker F4/80 can be used to define mouse EBI macrophage.We found that not all F4/80+Vcam1+CD169+macrophages are EBI macrophages.Instead,we discovered that EBI macrophages are characterized by the expression of Epor in both mouse and man.RNA-seq analyses of the newly identified EBI macrophages revealed that EBI macrophages have involved specialized function in supporting erythropoiesis.Our findings provide foundation for future studies.Here we will review current knowledge of EBI macrophages and discuss future perspectives.

Inhibition of aryl hydrocarbon receptor signaling promotes the terminal differentiation of human erythroblasts

The aryl hydrocarbon receptor(AHR)plays an important role during mammalian embryo development.Inhibition of AHR signaling promotes the development of hematopoietic stem/progenitor cells.AHR also regulates the functional maturation of blood cells,such as T cells and megakaryocytes.However,little is known about the role of AHR modulation during the development of erythroid cells.In this study,we used the AHR antagonist StemRegenin 1(SR1)and the AHR agonist 2,3,7,8-tetrachlorodibenzo-p-dioxin during different stages of human erythropoiesis to elucidate the function of AHR.We found that antagonizing AHR signaling improved the production of human embryonic stem cell derived erythrocytes and enhanced erythroid terminal differentiation.RNA sequencing showed that SR1 treatment of proerythroblasts upregulated the expression of erythrocyte differentiation-related genes and downregulated actin organization-associated genes.We found that SR1 accelerated F-actin remodeling in terminally differentiated erythrocytes,favoring their maturation of the cytoskeleton and enucleation.We demonstrated that the effects of AHR inhibition on erythroid maturation were associated with F-actin remodeling.Our findings help uncover the mechanism for AHRmediated human erythroid cell differentiation.We also provide a new approach toward the large-scale production of functionally mature human pluripotent stem cell-derived erythrocytes for use in translational applications.

Novel methods for studying normal and disordered erythropoiesis

Erythropoiesis is a process during which multipotential hematopoietic stem cells proliferate, differentiate and eventually form mature erythrocytes. Interestingly, unlike most cell types, an important feature of erythropoiesis is that following each mitosis the daughter cells are morphologically and functionally different from the parent cell from which they are derived, demonstrating the need to study erythropoiesis in a stage-specific manner. This has been impossible until recently due to lack of methods for isolating erythroid cells at each distinct developmental stage. This review summarizes recent advances in the development of methods for isolating both murine and human erythroid cells and their applications. These methods provide powerful means for studying normal and impaired erythropoiesis associated with hematological disorders.

Erythroid Lineage Cells in the Liver:Novel Immune Regulators and Beyond

The lineage of the erythroid cell has been revisited in recent years. Instead of being classified as simply inert oxygen carriers, emerging evidence has shown that they are a tightly regulated in immune potent population with potential devel-opmental plasticity for lineage crossing. Erythroid cells have been reported to exert immune regulatory function through secreted cytokines, or cell-cell contact, depending on the conditions of the microenvironment and disease models. In this review, we explain the natural history of erythroid cells in the liver through a developmental lens, as it offers perspec-tives into newly recognized roles of this lineage in liver biology. Here, we review the known immune roles of erythroid cells and discuss the mechanisms in the context of disease models and stages. Then, we explore the capability of erythroid lineage as a cell source for regenerative medicine. We propose that the versatile lineage of erythroid cells provides an underappreciated and potentially promising area for basic and translational research in the field of liver disease.