Title: mTORC1 plays an important role in osteoblastic regulation of B-lymphopoiesis
Authors: Martin, SK
Fitter, S
El Khawanky, N
Grose, RH
Walkley, CR
Purton, LE
Ruegg, MA
Hall, MN
Gronthos, S
Zannettino, ACW
Issue Year: 2018
Series Sci Rep:
Abstract Skeletal osteoblasts are important regulators of B-lymphopoiesis, serving as a rich source of factors such as CXCL12 and IL-7 which are crucial for B-cell development. Recent studies from our laboratory and others have shown that deletion of Rptor, a unique component of the mTORC1 nutrient-sensing complex, early in the osteoblast lineage development results in defective bone development in mice. In this study, we now demonstrate that mTORC1 signalling in pre-osteoblasts is required for normal B-lymphocyte development in mice. Targeted deletion of Rptor in osterix-expressing pre-osteoblasts (Rptor(ob)(-/-)) leads to a significant reduction in the number of B-cells in the bone marrow, peripheral blood and spleen at 4 and 12 weeks of age. Rptor(ob)(-/-) mice also exhibit a significant reduction in pre-B and immature B-cells in the BM, indicative of a block in B-cell development from the pro-B to pre-B cell stage. Circulating levels of IL-7 and CXCL12 are also significantly reduced in Rptor(ob)(-/-) mice. Importantly, whilst Rptor-deficient osteoblasts are unable to support HSC differentiation to B-cells in co-culture, this can be rescued by the addition of exogenous IL-7 and CXCL12. Collectively, these findings demonstrate that mTORC1 plays an important role in extrinsic osteoblastic regulation of B-cell development.
URI: https://publications.svi.edu.au/publications/4259
Other Identifiers 10.1038/s41598-018-32858-5
Publication type Article