Project description:Erythroblasts cultured from six healthy commercial available cord blood CD34+ cells were used to generate an cord blood erythroblast transcriptome. Cellular maturation was maintained including enucleation. On culture day 14 total RNA was isolated (see PMID: 23798711 for details). These RNA-Seq profiles were generated after flow cytometric sorting (live cell gating of culture Day 14 erythroblasts according to forward and side scatter).
Project description:The supply of red blood cells (RBCs) is not sufficient in many developing countries or in developed countries for patients who need chronic transfusion from best-matched donors. Ex vivo expansion and maturation of human erythroid precursor cells (erythroblasts) could represent a potential solution. Proliferating erythroblasts can be expanded from human umbilical cord blood mononuclear cells (CB MNCs) ex vivo for 10^6-10^7 fold (in ~50 days) before undergoing senescence. Here, we report that ectopic expression of three to four genetic factors that have been used for iPS cell derivation enables CB-derived erythroblasts to undergo extended ex vivo expansion (M-bM-^IM-%10^51 fold in ~9 months) in a defined suspension culture condition without change of cell identity or function. These vastly expanding erythroblasts maintain homogeneously immature erythroblast phenotypes, a normal diploid karyotype and dependence on specific combination of cytokines and hormone for survival and proliferation throughout the continuous expansion period. When switched to a culture condition for terminal maturation, these immortalized erythroblasts gradually exit cell cycle, decrease cell size, accumulate hemoglobin, condense nuclei and eventually give rise to enucleated hemoglobin-containing erythrocytes. Our result may ultimately lead to the development of unlimited sources of cultured RBCs for optimally-matched or personalized transfusion medicine. We compared the global gene expression profiles of different human cell types: iE: immortalized erythroblasts generated by genetic reprogramming from pCBE; pCBE: primary cord blood-derived erythroblasts; CD34+: CD34+ purified hematopoietic stem/progenitor cells from adult blood or fetal liver; TF-1: a human erythroleukemia cell line; ESC: human embryonic stem cells; iPSCs: human induced pluripotent stem cells. We want to see the relationship among these cell types. We included multiple samples (biological replicates) for most cell types.
Project description:The shortage of platelets is becoming increasingly prominent owing to their short shelf life, limited supply, and increasing demand in response to public health incidents. It is an attractive idea to obtain large numbers of transfusible megakaryocytes (MKs) and platelets from somatic cells via cell lineage reprogramming. However, generating human MKs from somatic cells using a pharmacological reprogramming approach has not been widely explored. Here, we report the successful generation of human induced MKs (iMKs) from cord blood erythroblasts (EBs) using a chemical reprogramming strategy with a combination of four small molecules (4M): Bix01294, RG108, VPA, and PD0325901. The iMKs exhibited the ability to produce proplatelets and release vital functional platelets in vitro, demonstrating their similarity to natural MKs. Importantly, after injection into mice, iMKs were able to mature and give rise to functional platelets that were incorporated into newly formed thrombi. The reprogramming process was carefully examined using single-cell RNA sequencing, which revealed an efficient, rapid, and successful cell fate conversion of EBs to iMKs by 4M via the intermediate state of bipotent precursors. Assay for transposase-accessible chromatin sequencing results indicated that 4M induced genome-wide chromatin remodeling during MK reprogramming from EBs. 4M drove the transition of the transcription factor gene network by downregulating the key erythroid transcription factor genes KLF1 and MYB and subsequently upregulating MK development-associated transcription factor genes, including FLI1 and MEIS1. This process eventually led human cord blood EBs to acquire the MK fate. Thus, our chemical reprogramming of cord blood EBs to iMKs provides a simple and efficient approach to generating clinically transfusible MKs and platelets.
Project description:Human erythroblasts purified from cord blood were cultured in vitro and FACS-sorted into five highly purified populations representing distinct differentiation stages: proerythroblasts, early basophilic erythroblasts, late basophilic erythroblasts, polychromatophilic erythroblasts, and orthochromatophilic erythroblasts. The methods for culture and sorting experiments are given in Hu et al. 2013. For each RNA-seq library, RNA was isolated from 1x 106 sorted human erythroblasts using RNeasy Plus Mini kits (Qiagen). Libraries were then prepared using Illumina TruSeqTM RNA kits to obtain 50 nt reads. Collaborators at the New Your Blood Center were responsible for erythroblast culture, FACS purification of erythroblast populations, and acquisition of RNA-seq data. Collaborators at U.C. Berkeley and Lawrence Berkeley National Laboratory performed data analysis and experimental validation of alternative splicing in erythroblasts. Results: Differentiating erythroblasts execute a dynamic alternative splicing program that is enriched in genes affecting cell cycle, organelle organization, chromatin function, and RNA processing. Alternative splicing plays a major role in regulating gene expression to ensure synthesis of appropriate proteome at each stage as the cells remodel in preparation for production of mature red cells.
Project description:Human erythroblasts purified from cord blood were cultured in vitro and FACS-sorted into five highly purified populations representing distinct differentiation stages: proerythroblasts, early basophilic erythroblasts, late basophilic erythroblasts, polychromatophilic erythroblasts, and orthochromatophilic erythroblasts. The methods for culture and sorting experiments are given in Hu et al. 2013. For each RNA-seq library, RNA was isolated from 1x 106 sorted human erythroblasts using RNeasy Plus Mini kits (Qiagen). Libraries were then prepared using Illumina TruSeqTM RNA kits to obtain 50 nt reads. Collaborators at the New Your Blood Center were responsible for erythroblast culture, FACS purification of erythroblast populations, and acquisition of RNA-seq data. Collaborators at U.C. Berkeley and Lawrence Berkeley National Laboratory performed data analysis and experimental validation of alternative splicing in erythroblasts. Results: Differentiating erythroblasts execute a dynamic alternative splicing program that is enriched in genes affecting cell cycle, organelle organization, chromatin function, and RNA processing. Alternative splicing plays a major role in regulating gene expression to ensure synthesis of appropriate proteome at each stage as the cells remodel in preparation for production of mature red cells. Erythroid differentiation stage-specific transcriptome analysis was performed by RNA-seq analysis of highly purified erythroblast populations
Project description:The supply of red blood cells (RBCs) is not sufficient in many developing countries or in developed countries for patients who need chronic transfusion from best-matched donors. Ex vivo expansion and maturation of human erythroid precursor cells (erythroblasts) could represent a potential solution. Proliferating erythroblasts can be expanded from human umbilical cord blood mononuclear cells (CB MNCs) ex vivo for 10^6-10^7 fold (in ~50 days) before undergoing senescence. Here, we report that ectopic expression of three to four genetic factors that have been used for iPS cell derivation enables CB-derived erythroblasts to undergo extended ex vivo expansion (≥10^51 fold in ~9 months) in a defined suspension culture condition without change of cell identity or function. These vastly expanding erythroblasts maintain homogeneously immature erythroblast phenotypes, a normal diploid karyotype and dependence on specific combination of cytokines and hormone for survival and proliferation throughout the continuous expansion period. When switched to a culture condition for terminal maturation, these immortalized erythroblasts gradually exit cell cycle, decrease cell size, accumulate hemoglobin, condense nuclei and eventually give rise to enucleated hemoglobin-containing erythrocytes. Our result may ultimately lead to the development of unlimited sources of cultured RBCs for optimally-matched or personalized transfusion medicine.