Attention:

Certain features of Sigma-Aldrich.com will be down for maintenance the evening of Friday August 18th starting at 8:00 pm CDT until Saturday August 19th at 12:01 pm CDT.   Please note that you still have telephone and email access to our local offices. We apologize for any inconvenience.

Growth Factors in Stem Cell Biology

By: Jennifer Fries, BioFiles 2009, 4.5, 11.

Growth factors are naturally occurring regulatory molecules, which bind to receptors on the cell surface. They stimulate cell and tissue function through influencing cell differentiation by changing their biochemical activity and cellular growth, and regulating their rate of proliferation. Numerous families of growth factors have already been identified and remarkable advancements have been made in understanding the pathways growth factors use to activate cellular proliferation and differentiation.

Medical researchers recognize the important role growth factors play in stem cell therapy and regenerative medicine. Stem cell research has the potential to dramatically change the treatment of human disease and serious injuries by providing a platform for deciphering the secrets surrounding the cellular processes controlling development, aging, and tissue regeneration. Regenerative medicine shows promise for repair of damaged tissues and organs, deliver safer and more efficient drugs, better disease models, and cures for numerous devastating diseases.

Stem cell treatment could put an end to inefficient disease treatments and lack of organ donations for organ transplants. Much is expected from Embryonic Stem Cell (ESC) research, due to their ability to differentiate into all possible cell types in the body and their potentially unlimited capacity for self-renewal. However, no approved medical therapies have been developed using ESC, due to the lack of understanding these cells and how are they influenced. Once growth factors are added to pluripotent stem cells under certain conditions, they are able to direct differentiation into three different germ layers, endoderm, mesoderm, and ectoderm, from which various cell types are derived. Endodermal cells develop into the liver and pancreas, mesodermal cells give rise to muscles and red blood cells, and ectodermal cells become the brain and skin. Tremendous progress has been made in understanding which growth factors manipulate the different lineage pathways. However, complete control of stem cell differentiation, from pluripotent to fully specialized cell, needs further investigation since it requires multiple growth factors in defined order and quantity and at defined time intervals.


This image shows cells derived from the culture of neural stem cells grown in the presence of EGF (Cat. No. E9644) and LIF (Cat. No. L5283). The cells were expanded in neural stem cell expansion medium (Cat. No. S3194) and then moved to conditions to allow them to differentiate.

This photo shows differentiated cells fixed and stained with an antibody for GFAP (an astrocyte marker in green, Cat. No. G9269). Actin is labeled with TRITC phalloidin (Cat. No. P1951) and the nuclei are labeled with DAPI (Cat. No. D8417).

A recent advancement in the field of regenerative medicine is the production of induced pluripotent stem (iPS) cells. iPS cells are embryonic-like stem cells, derived from reprogrammed adult cells. The use of iPS cells in place of embryonic stem cells from human embryos provides an avenue for creating an unlimited supply of embryonic-like stem cells generating a tremendous enthusiasm in this field. Induced pluripotent stem cell technology has enormous possibilities for safe treatment of numerous diseases, bypassing the current ethical and political issues of embryonic stem cells. Also, iPS cells allow for personalized medicine as both the nuclear and the mitochondrial DNA matches the donor. Furthermore, using iPS cells would not require any immune suppression, making them a superior choice over donor embryonic stem cells for therapeutic uses. Researchers are daily enhancing their already significant understanding of how growth factors affect both somatic and embryonic stem cell expansion and differentiation. However, they have only begun to explore the effects of growth factors on iPS cells and how they differ, if at all, from embryonic stem cells. Once they can completely control the fate of pluripotent stem cells, which is influenced by a number of cellular signals including growth factors, they will be able to direct these cells, both in vivo and in vitro, to become the specialized cells that make up all the tissue in the body and enable subsequent use in cell-based therapies, drug development, and disease modeling.

back to top

Materials

     
Related Links