Louis A. Garfinkle Memorial Laboratory Fund
Report 9/1/07

The Louis A. Garfinkle Memorial Laboratory Fund was established in February 2007 to fund developmental biology research as it relates to stem cells in the Ellen V. Rothenberg laboratory. The funds raised for this research are restricted for the sole purpose of purchasing needed equipment, repair of existing equipment, and supplying research reagents.

Stem cells have the potential to develop into many different cell types in the body. From the start of life all cells derive from embryonic stem cells which have the potential to become any kind of cell. As the body develops and matures, stem cells narrow their potential into more specific kinds of cells. We see them at work when our bodies repair themselves after a wound has occurred or when we lose blood and the body replenishes the blood back to normal levels. In theory, stem cells can divide without limit and have the potential to either remain a stem cell or become another type of cell with a more specialized function, such as a muscle cell, a red blood cell, or a brain cell.

The Rothenberg laboratory has been studying the development of the immune system since its establishment in 1982. Of particular interest to this fund is their research on the regulation and control of hematopoietic multipotent stem cells and the narrowing of their potential into different kinds of blood cells (T cells, B cells, mast cells, macrophages, natural killer cells etc.). Studying the molecular regulatory factors that control the fate of these cells will hopefully illuminate the kinds of mechanisms that will help to understand how potentials are activated and directed toward distinct cellular roles. These mechanisms have direct implications in the control of cellular reproduction, reprogramming, fate commitment and specification which may be useful in controlling gene therapies, cancer, and tissue engineering.

As of September 1, 2007, $23,730.00 has been donated to the LAGMLF. These funds have been used so far purchase the following equipment and reagents:

• HERAcell CO2 double stack 10.6 cubic feet incubator with solid copper inner casing and fittings. This was purchased to replace a 25 year old unrepairable incubator that had been housing our culture system for growing mouse embryonic stem cells on stromal feeder layers engineered to produce a ligand which signals functional changes in T-lymphocyte precursor cells. The copper lining is important to inhibit fungal growth which can occur under the humid warm conditions needed for the growth of the cells. ($5,769.69)
• Taylor Wharton 3K series liquid nitrogen cell storage system with inventory control. This piece of equipment was purchased to replace a 25 year old failed storage system used for the long term storage of our culture stocks and clone archives. ($3,837.50)
• Antibodies to cell markers CD25, CD117, and CD45 conjugated to the new fluorochrome, Pacific Blue. These antibodies mark certain kinds of cells in combination with other antibodies and fluorochromes. This will allow the researchers to increase the number cell surface markers used to identify analyze and purify cells at various stages of cell development using flow cytometric technology and cell sorting for the molecular characterization of cell fate. ($724.09)

Research Highlights:

In first half of 2007, two research papers from the Rothenberg lab were published that shed light on the way cells gradually adopt T-cell properties and gradually give up their stem cell properties. One article (Tydell et al.) showed that most regulatory proteins of stem cells persist throughout the early stages of T-cell development, so that T-cell properties are first turned on in cells that still have a great deal of stem-cell like nature. However, the same study identified two extremely interesting new regulatory proteins that the immature T-cells turn on at a key early transition, and these apparently mark the break from their stem-cell ancestors. One of these new regulatory proteins, named “Bcl11b”, is totally specific for the T-cell development pathway and is now being studied in depth to see exactly how it may guide the switch from stem cell to T cell.

The other article (Taghon et al.) focused on a regulatory molecule that is already known to be important for making T cells, named “GATA-3”. It has been known for some time that T cells cannot develop at all if GATA-3 is missing, but what was not clear before is how extremely delicately it must itself be controlled. We found that even though GATA-3 is essential, too much of it not only can block T cell development, but also can push the immature cells into a completely different, inappropriate developmental path. This finding has possible relevance for immune system diseases and also has general implications for clinical gene therapy. The vital question is how to control the expression of such powerful regulatory molecules accurately in order to help make a desired cell type, like T cells. New research by a graduate student in the lab is now starting to shed light on the detailed mechanism that controls GATA-3 expression properly in normally developing T cells.