3031 – HEMATOPOIETIC STEM CELLS GENERATE THEIR OWN HEMATOPOIETIC MICROENVIRONMENT

• Published in: Experimental hematology 2021-08, Vol.100, p.S58-S58
• Main Authors: Sacma, Mehmet, Mulaw, Medhanie, Hageb, Ali, Bogeska, Ruzhica, Sakk, Vadim, Vollmer, Angelika, Marka, Gina, Soller, Karin, Milsom, Michael, Florian, Maria, Geiger, Hartmut
• Format: Article
• Language: English
• ISSN: 0301-472X; 1873-2399
• DOI: 10.1016/j.exphem.2021.12.252

Quantitative 3D imaging of organ-wide cellular and subcellular components is central for revealing and understanding complex interactions between stem cells and their microenvironment. In situ or in vivo 3D quantitative imaging remains technically challenging, which restricts its more widespread use in stem cell research. The quantitative nature of the interrelationship of hematopoietic stem cells (HSCs) with their progeny, which count for the vast majority of bone marrow (BM) cells, and with other niche components remains only partially characterized. We recently designed a fast but gentle methodology termed iFAST3D that enables reproducible and quantitative high-fidelity 3D imaging of HSCs and their progeny within BM or various niche components, all simultaneously. iFAST3D is a very versatile and easy to apply resource. Using this approach, we demonstrate that HSCs are frequently localized proximal to a subset of early lymphoid progenitor cells (ELPs). HSCs located in the central-sinusoidal BM build a microenvironment by their own megakaryocytes, whereas HSCs in the endosteal-arteriolar BM are frequently localized proximal to a subset of ELPs, produced by themselves, which generate their microenvironment. In addition, the microenvironment in which quiescent HSCs reside are themselves proliferation quiescent BM regions, which imply a coupling of the activation status of HSCs and the niche.