Activin A: Role in Stem Cell Development & Hematopoiesis – A Research Review
Researchers are increasingly focused on harnessing the potential of induced pluripotent stem cells (iPSCs) to generate specific blood cell types, particularly given the limitations of relying solely on bone marrow donation for treatments. A body of research spanning decades demonstrates the significant role of Activin A in regulating both the creation of blood cells and the maintenance of stem cell characteristics.
Early investigations in 1992 and 1993 established Activin A’s influence on erythroid progenitors – cells destined to become red blood cells. Studies published in Blood showed that Activin A stimulated the proliferation and differentiation of these progenitors, while simultaneously suppressing the growth of granulocyte-macrophage colony-forming progenitors, precursors to white blood cells. This suggested a targeted regulatory effect on specific blood cell lineages.
Further research in 2002, also in STEM CELLS, broadened the understanding of Activin A’s role, defining it as a key regulator of hemopoiesis – the formation of blood cellular components. This foundational work paved the way for exploring Activin A’s impact on pluripotent stem cells themselves.
In 2005, scientists demonstrated that Activin A could maintain the pluripotency of human embryonic stem cells without the need for feeder layers, traditionally used to support stem cell growth. This was a significant step towards more controlled and scalable stem cell cultivation. This ability to maintain pluripotency was later confirmed in 2011 with human induced pluripotent stem cells, published in Experimental and Therapeutic Medicine.
The influence of Activin A extends beyond simply maintaining stem cell identity. Research published in 2010 in Stem Cell Research & Therapy revealed that Activin A expression regulates the multipotency of mesenchymal progenitor cells, suggesting a broader role in directing cell fate. A 2012 study in Stem Cells and Development further clarified this, showing that Activin A promotes the development of hematopoietic-fated mesoderm – the embryonic tissue that gives rise to blood cells – through the upregulation of Brachyury.
Recent advancements have explored combining Activin A with other factors to enhance hematopoietic cell development. A 2015 study in Biochemical and Biophysical Research Communications found that Activin A, when used in conjunction with OP9 cells, facilitated the development of specific types of hematopoietic mesodermal cells from murine embryonic stem cells. This highlights the potential for synergistic effects when combining Activin A with other established cell culture techniques.
The therapeutic potential of Activin A is also being investigated. A 2008 study in Stem Cells and Development demonstrated that delivering Activin A-overexpressing embryonic stromal cells to the bone marrow specifically modified B lymphopoiesis – the development of B cells, a crucial component of the immune system. This suggests a targeted approach to modulating immune function through stem cell-based therapies.
Current research, as highlighted by a 2024 Frontiers publication, is focused on deriving megakaryocytes and platelets from iPSCs, with Activin A playing a crucial role in these protocols. Another Frontiers article from 2024 details the diversity of protocols for deriving macrophages from iPSCs, a field where Activin A’s influence is also being actively explored. Recent work published in Nature details the long-term engraftment of multilineage hematopoietic cells differentiated from human iPSCs, a critical step towards clinical application.