Project description:These experiments treated cord blood-derived megakaryocytes with Cortistatin A for 0-8 h and analyzed resultant gene expression changes by microarray analysis.
Project description:Ex vivo differentiation of megakaryocytes (Mk) was carried out using human cord blood (CB) CD34+ cells under the stimulation of recombinant human interleukin-3, stem cell factor, and thrombopoietin for 7 days, followed by thrombopoietin treatment alone for further 3 days. Total cellular RNA was extracted from Day-0 CD34+, Day-10 CD41+ and CD41- cells, respectively. Microarray was performed and the data was analyzed using the GeneChip Operating Software, Spotfire DecisionSite Software and Genomatix Application Software.
Project description:Characterize the genes regulated by MKL1/SRF complex in human megakaryocytes (MKs) derived from cord blood or cytapheresis : Using a knock down approach by small interference of MKL1 in MK progenitors, we observed a decrease in the percentage of cells with actin polymerization after adhesion on various substrates, an increase of mean ploidy level and apoptosis. Furthermore, MKL1 inhibition induced a major defect in pro-platelet formation and MKs migration. These results clearly demonstrate that MKL1 is involved in the cytoskeleton organization and maturation of MKs as well as in platelet formation. The goal of gene profiling was to identify new potential MKL1/SRF targets the expression level of which was down regulated after MKL1 inhibition: Human CD34+ cells isolated from cord blood or cytapheresis were transduced by a control lentivirus (designed as SCR; scramble) or by the lentivirus encoding for shRNA of MKL1 (designed as shMKL1) both containing a GFP expressed under the control of PGK promoter. The cells were than grown in serum free medium supplemented by thrombopoietin leading to a generation of megakaryocytes. At day 9 of culture (80% of MKs), the GFP positive cells were sorted, RNAs were extracted and submitted to hybridization as described in annex protocols. Two lists of genes (one for cord blood samples and one for cytapheresis samples) deregulated after the repression of MKL1 were done comparing the intensity of hybridization between SCR and shMKL1 samples. The common list of genes deregulated in MKs from cord blood and cytapheresis after the repression of MKL1 was than generated.
Project description:Cells obtained from adipose tissue are able to differentiate into megakaryocytes. We compared the gene expression profile of human adipose tissue derived megakaryocytes with that of megakaryocytes differentiated from human CD34 positive cord blood hematopoietic stem cells.
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.