The effect of bone morphogenetic protein-4 on haematopoietic stem cells
Prof C Kinnon
Child Health Research Appeal Trust Studentship
Description of Project:
Bone morphogenetic protein-4 (BMP4) is highly expressed at sites of haematopoietic stem cell (HSC) formation. In human embryo development, BMP4 is strongly expressed by cells underlying the ventral floor of the dorsal aorta where HSC formation occurs. The leukemia associated genes Runx1, Scl, Gata2 and Lmo2 are vital to the development of the haematopoietic system, and deletion of these genes produces an embryonic lethal phenotype due to the absence of blood formation. This study investigated whether BMP4 up regulates the expression of these genes. The role of BMP4 was explored during HSC development in an embryonic stem (ES) cell differentiation model and at later developmental stages using ex vivo foetal liver and bone marrow serum free cultures. Differentiating ES cells cultured in serum-free medium were found to express BMP4 and the BMP receptor endogenously. To establish a model for exogenous BMP4 addition in isolation, lentiviral vectors were used to deliver short hairpin RNA (shRNA) for sustained RNAi knockdown of endogenous Bmp4 expression during ES cell differentiation. Exogenous BMP4 alone was found to induce simultaneous expression of Runx1, Scl, Gata2 and Lmo2. Thus BMP4 appears to play a central role in the induction of a haematopoietic genetic program through the expression of these genes critical to the development of the haematopoietic system.
Abeyewickreme A., Thrasher A.J., Kinnon C. 2011 “Bone morphogenetic protein-4 (BMP4) up regulates key haematopoietic genes in differentiating embryonic stem cells treated with BMP4 short hairpin RNA” British Journal of Haematology 10.1111/j.1365-2141.2011.08759.x.
Abeyewickreme A., Kwok A., Mc Ewan J.R., Jayasinghe S.N. 2009 “Bio-electrospraying embryonic stem cells: interrogating cellular viability and pluripotency” Integrative Biology 1 (3) 225-284