Regulation of murine B lymphopoiesis by stromal cells

Abstract

During the past two decades, there has been a significant increase in our understanding of how B lymphopoiesis is extrinsically regulated by stromal cells. The information on the stromal cell types that are now known to have important roles in regulating B lymphopoiesis has largely been obtained from studies in mice. Many of these studies (such as specifically knocking out a gene of interest in a particular stromal cell type) cannot be done in humans. Hence, this review focuses on what we have learned about the extrinsic regulation of B lymphopoiesis from studies in mice.It should be noted that there are some differences in the regulation of B lymphocyte production between mice and humans, which have been extensively reviewed by Ichii et al 1 A major difference between the two species is the role of the spleen in B lymphopoiesis. As is discussed further below, the spleen is a major site for the maturation of B lymphocytes in mice; however, in humans, it is a crucial reservoir of memory B cells 2 but does not contribute to B lymphocyte maturation. Cell surface markers that identify each of the developing B lymphocyte populations are also different between mice and humans. 1 Nevertheless, the information gained from studies in mice is very valuable and, with

Deletion of Vhl in Dmp1-Expressing Cells Causes Microenvironmental Impairment of B Cell Lymphopoiesis

“…The BM contains specialized microenvironments that maintain blood cells and supply factors required for their development and maintenance. Perivascular stromal cells, osteoprogenitor cells, endothelial cells (ECs), MSCs, OBs and OCYs are critical B cell "niches" and are all cells that support B cell development (1,4,25,26), in part through production of cytokines. Essential cytokines for B cell development include CXC-chemokine ligand 12 (CXCL12) (27)(28)(29), FLT3 ligand (FLT3L) (30), IL-7 (30)(31)(32)(33), stem-cell factor (SCF) (31,32) and receptor activator of nuclear factor-kB ligand (RANKL) (34).…”