Project description:Comparative transcriptomic profiling of pulmonary and medullary CD34+ haematopoietic progenitor was performed to reveal shared and organ-specific gene signatures.
Project description:Haematopoietic stem and progenitor cells (HSPCs), the precursors of all blood cells, reside predominantly in the bone marrow. Yet, a small proportion (<1%) of phenotypic HSPCs is also found in extramedullary tissues, such as spleen, where they contribute to blood production under stress conditions. However, the detailed characterization of extramedullary HSPCs remains poor. Here, we analyse the single-cell composition of the adult human HSPC pool within the spleen from two patients with hereditary spherocytosis (HS), a disorders causing abnormal red blood cells. 10x scRNA-seq of CD19- CD34+ HSPCs was paired with single-cell functional analysis using most immature haematopoietic stem cells and multipotent progenitors (HSC/MPPs). We find that HSC/MPPs from HS spleens have a stronger transcriptional and functional bia towards the erythroid lineage than control sample.
Project description:Haematopoietic stem and progenitor cells (HSPCs) in the foetus and adult possess distinct molecular landscapes that regulate cell fate and change their susceptibility to initiation and progression of haematopoietic malignancies. The proteomic programs that govern these differences remain elusive. In this study, we have utilized a mass spectrometry-based quantitative proteomics approach to comprehensively describe and compare the proteome of foetal and adult HSPCs. We found that the proteome of foetal HSPCs is relatively simple, characterized by proteins involved in cell cycle and cell proliferation, while their adult counterparts are defined by a larger set of proteins that are involved in more diverse cellular processes. These adult characteristics include an arsenal of proteins important for viral and bacterial defence, as well as protection against ROS-induced protein oxidation. Our further analyses of Type I interferon signalling shows that foetal HSPCs are sensitive to Interferon a (IFNa), which impairs their production of mature lymphoid cells, whereas stimulation with IFNa to the pregnant mother enhances the production of early progenitors from foetal HSCs. Our results provide new and important insights into the molecular landscape of foetal and adult haematopoiesis that advance our understanding of normal and malignant haematopoiesis during foetal and adult life.
Project description:Blood is generated by a constant stream of differentiating haematopoietic progenitor cells. The process is controlled by an immensely complex gene regulatory networks. These have been difficult to comprehend using correlative evidence and limited systematic functional data. Hoxb8-FL cell line is a model system of lympho-myeloid progenitors, which self-renews in vitro and is amenable to genetic perturbations. To construct a functionally defined transcription factor (TF) network we targeted 39 transcription factors using CRISPR/Cas9 gene targeting in Hoxb8-FL cells. We measured the resulting transcriptional changes by small scale RNA-Seq within 2-4 d of each perturbation. Our network analysis revealed >17,000 TF-target interactions across >7,000 target genes, established new interactions among TFs and shed new light on the mechanisms maintaining self-renewal and multipotency.
Project description:Transcriptional profiling of four cell populations to understanding chronic myeloid leukaemia in humans. The populations are normal haematopoietic stem cells (HSC), normal progenitor cells (HPC), CML stem cells (LSC) and CML progenitor cells (LPC).
Project description:Haematopoietic stem and progenitor cell (HSPC) transplant is a widely used treatment for life-threatening conditions including leukemia; however, the molecular mechanisms regulating HSPC engraftment of the recipient niche remain incompletely understood. Here, we developed a competitive HSPC transplant method in adult zebrafish, using in vivo imaging as a non-invasive readout. We used this system to conduct a chemical screen and identified epoxyeicosatrienoic acids (EET) as a family of lipids that enhance HSPC engraftment. EETs’ pro-haematopoietic effects are conserved in the developing zebrafish, where this molecule promotes HSPC specification through activating a unique AP-1/runx1 transcription program autonomous to the haemogenic endothelium. This effect requires the activation of PI3K pathway, specifically PI3Kg. In adult HSPCs, EETs induce transcriptional programs including AP-1 activation, modulating multiple cellular processes, such as migration, to promote engraftment. Finally, we demonstrated that the EET effects on enhancing HSPC homing and engraftment are conserved in mammals. Our study established a novel method to explore the molecular mechanisms of HSPC engraftment, and discovered a previously unrecognized, evolutionarily conserved pathway regulating multiple haematopoietic generation and regeneration processes. EETs may have clinical application in marrow or cord blood transplantation.
Project description:Haematopoietic stem cells reside in the bone marrow where they generate the effector cells that drive immune responses. However, in response to inflammation some haematopoietic stem and progenitor cells (HSPC) are recruited to tissue sites and undergo extramedullary haematopoiesis. Contrasting this paradigm here we show, with single cell sequencing, residence and differentiation of HSPC in healthy gingiva, a key oral barrier, in the absence of overt inflammation.