Finding a niche Nonmyelinating Schwann cells maintain hematopoietic stem cell hibernation in the bone marrow niche
Hematopoietic stem cells (HSCs) located in the bone marrow supply us with tens of billions of new blood cells every day through cell division. Typically though the majority of HSCs are in a state of hibernation and only a small fraction undergoes mitosis. HSC hibernation is an essential mechanism for preventing cell depletion or abnormality as a result of this frequent mitosis and to ensure a lifelong supply of blood cells.
These dormant HSCs are thought to exist in a microenvironment termed the bone marrow niche. However, the location of the niche and the mechanism by which hibernation is maintained were almost completely unknown.
Professor Hiromitsu Nakauchi and his research group at the Institute of Medical Science have demonstrated for the first time that the bone marrow niche includes nonmyelinating Schwann cells, a type of glial nerve cell, and have described the mechanism by which hibernation is maintained. Until now it was thought that the nervous and hematopoietic systems were independent.
The research group determined that glial cells suppress HSC division by activating the protein TGF-β, and that HSCs in the bone marrow niche are affected by TGF-β through contact with glial cells.
In recent years, it has been pointed out that even leukemia stem cells exist in a state of hibernation in the bone marrow niche. This research result is important not only for understanding the mechanism of hematopoiesis but also for elucidating the pathogenesis of recurrent leukemia and may lead to the development of new therapies.
Department release/press release (Japanese)
Satoshi Yamazaki, Hideo Ema, G?ran Karlsson, Tomoyuki Yamaguchi, Hiroyuki Miyoshi, Seiji Shioda, Makoto M. Taketo, Stefan Karlsson, Atsushi Iwama, Hiromitsu Nakauchi,
“Nonmyelinating Schwann Cells Maintain Hematopoietic Stem Cell Hibernation in the Bone Marrow Niche”,
Cell Vol. 147, Issue 5, pp. 1146-1158. doi:10.1016/j.cell.2011.09.053