New Embryonic Stem Cell Lines Avoid Animal Products

Researchers at Stanford University School of Medicine derived new human embryonic stem cell lines using minimal animal products. Although numerous groups have derived stem cell lines, most were generated in the presence of animal serum and animal-derived feeder cells. These animal products are a concern because they may cause the stem cells to produce an immune response when transplanted into humans and may induce biological changes especially to the genome. In this study, the team characterized six lines that were derived with minimal use of animal products.  The researchers verified that the lines behave like normal ES cells in their ability to both self-renew and differentiate to the major cell types.  These lines may be useful for future studies that help move the field toward clinical-grade cell therapy.

Stem Cells and Development: June 17, 2008
CIRM funding: Renee Reijo Pera (RC1-00137)

Related Information: Stanford Stem Cell Biology and  Regenerative Medicine Institute, Pera lab page

Fly Stem Cells Create their Home

Researchers at the Salk Institute of Biological Studies discovered that stem cells in the testes of fruit flies are able to generate their own support cells. This work in flies could help guide researchers hoping to understand the environment surrounding resident populations of human stem cells - called the niche. The niche is difficult to study in humans but is an area of great interest because any therapy based on transplanting stem cells into a tissue will require those cells to be paced in a niche where they will thrive. This work raises the possibility that some transplanted stem cells may be able to produce their own niche.

Nature: July 20, 2008
CIRM funding: Justin Voog (T1-00003)

Related Information: Salk press release, Salk Institute for Biological Studies

Aging Muscles Inhibit Stem Cells, Prevent Repair

Researchers at UC, Berkeley identified a signaling molecule that interferes with the ability of older skeletal muscle to regenerate. After injury, adult skeletal muscle regenerates by activating muscle stem cells that fuse with the existing muscle cells to repair the damage. This ability to regenerate diminishes with age, not because of a decline in the number of resident stem cells, but because stem cells in the older muscle don’t respond when damage occurs. It turns out that older muscles release molecules that actively inhibit the resident stem cells. In this study, the team identified one of those molecules and showed that interfering with that molecule’s function restores the ability of muscle in older mice to regenerate after injury. This research illustrates the potential for recruiting adult resident stem cells in tissue repair.

Nature: June 15, 2008.
CIRM funding: Morgan Carlson (T1-00007)

Related Information: Press release, Berkeley Stem Cell Center

Mutation Revealed to Convert Blood Stem Cells to Cancer Stem Cells

Researchers at UC, Los Angeles discovered a series of mutations that can convert normal blood stem cells into cancer stem cells. It is believed that many types of cancer result from cancer stem cells created by such mutations. In this case the first mutation converted normal stem cells and then caused over expression of an oncogene, a cancer gene, resulting in a proliferation of leukemia stem cells and acute T-cell lymphoblastic leukemia in a mouse model. The team hopes that by studying these pathways they will find ways to block them with small molecule drugs and cure the often fatal disease.

Nature: May 22, 2008
CIRM funding: Wei Guo (T1-00005)

Related Information: UCLA press release, The Eli and Edythe Broad  Center of Regenerative Medicine and Stem Cell Research at UCLA

Pattern of Small Genetic Factors Found to Characterize Embryonic Stem Cells

Researchers at The Scripps Research Institute discovered that human embryonic stem cells have a very specific signature when it comes to the regulators of their genes. MicroRNAs are very small, naturally occurring bits of genetic material. They don't code for specific proteins like genes do, but they regulate the activity of genes and turn on and off their protein production. In embryonic stem cells microRNAs are actively preventing the production of proteins that tell cells to differentiate into specific heart or bone tissue, for example, but are pushing hard on genes that result in self-renewal. The team hopes to use these microRNAs to reprogram any type of cell to become as pluripotent as embryonic stem cells and to do it more safely than current reprogramming called iPS.

Stem Cells: June, 2008
CIRM funding: Louise Laurent (T1-00003)

Related Information: Press release , The Scripps Research Institute

First clinical Trial Begins for a Therapy Enabled By CIRM Funding

Researchers at UC, San Diego verified a suspect gene mutation in blood-forming stem cells was by itself necessary and sufficient to cause a class of severe blood diseases called myeloproliferative disorders. They then worked with a team of researchers from other academic institutions and from the San Diego pharmaceutical company TargeGen to conduct animal tests of a compound TargeGen had already isolated and shown to inhibit that same genetic pathway. As a result of this broad collaboration, human clinical trials for this potential therapy began in February, 2008.



CIRM funding: Catriona Jamieson

Related Information: UC San Diego press release, UCSD Stem Cell Initiative

Method Produces Nerve Cells More Quickly

Researchers at the Burnham Institute for Medical Research have developed a new way of quickly maturing embryonic stem cells into neural cells. Other research groups have worked out lab conditions that encourage embryonic stem cells to mature into various types of nerve cells, but those methods were slow and resulted in early stage nerve cells that were more likely to cause tumors when transplanted into mice. This new method could speed work by researchers who are trying to develop therapies for diseases of the nervous system. As an additional benefit, this work showed that some previously overlooked genes are worth studying as potential regulators of embryonic stem cell maturation.

Cell Death and Differentiation: March 13, 2009
CIRM authors: R Bajpai (T2-00004), Stuart Lipton (RC1-00125), Alexi Terskikh (RS1-00466)

Related Information: Press release, Burnham Institute for Medical Research, Lipton bio, Terskikh bio