Robust temporal map of human in vitro myelopoiesis using single-cell genomics
Clara Alsinet1,2, Maria Nascimento Primo3,4, Valentina Lorenzi3
1Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, CB10 1SA, UK. ca6@sanger.ac.uk.
Insights
This study maps human induced pluripotent stem cell (iPSC) differentiation into macrophages, revealing early hematopoietic processes and generating diverse myeloid cells like dendritic cells (DCs). The findings offer a resource for understanding fetal hematopoiesis and developing immunotherapies.
Area of Science:
- Stem cell biology
- Immunology
- Hematopoiesis
Background:
- Myeloid cells are crucial for immune responses and maintaining bodily balance.
- Understanding in vitro myelopoiesis is vital for research, immunotherapies, and comprehending human blood cell development.
- Human induced pluripotent stem cells (iPSCs) offer a model for studying early hematopoiesis.
Purpose of the Study:
- To create a detailed molecular map of human iPSC differentiation into macrophages.
- To investigate the recapitulation of in vivo hematopoietic processes in vitro.
- To develop and validate protocols for generating iPSC-derived myeloid cells, including dendritic cells (DCs).
Main Methods:
- Generation of a large-scale (over 470,000 cells) molecular map of iPSC differentiation.
- Integration of in vitro data with in vivo single-cell atlases.
- CRISPR/Cas9 gene editing to validate the function of key transcription factors.
Main Results:
- In vitro iPSC differentiation mirrors early yolk sac hematopoiesis before definitive hematopoietic stem cells (HSCs) arise.
- Multiple myeloid lineages, including mast cells and monocytes, are generated independently of HSCs.
- Identification of novel myeloid progenitors and conserved regulatory programs between in vitro and in vivo systems.
- Successful protocol development for iPSC-derived dendritic cells (cDC2) and validation of transcription factor roles.
Conclusions:
- The study provides a comprehensive roadmap of human myeloid differentiation from iPSCs.
- This resource aids in studying human fetal hematopoiesis and exploring new therapeutic avenues.
- The findings highlight the potential of HSC-independent hematopoiesis for generating diverse myeloid cells.
Abstract:
Myeloid cells are central to homeostasis and immunity. Characterising in vitro myelopoiesis protocols is imperative for their use in research, immunotherapies, and understanding human myelopoiesis. Here, we generate a >470K cells molecular map of human induced pluripotent stem cells (iPSC) differentiation into macrophages. Integration with in vivo single-cell atlases shows in vitro differentiation recapitulates features of yolk sac hematopoiesis, before definitive hematopoietic stem cells (HSC) emerge. The diversity of myeloid cells generated, including mast cells and monocytes, suggests that HSC-independent hematopoiesis can produce multiple myeloid lineages. We uncover poorly described myeloid progenitors and conservation between in vivo and in vitro regulatory programs. Additionally, we develop a protocol to produce iPSC-derived dendritic cells (DC) resembling cDC2. Using CRISPR/Cas9 knock-outs, we validate the effects of key transcription factors in macrophage and DC ontogeny. This roadmap of myeloid differentiation is an important resource for investigating human fetal hematopoiesis and new therapeutic opportunities.
