Paul Sammak, PhD

Dr. Sammak is a Research Associate Professor in the Department of Cell Biology and Physiology. His research focuses on the use of embryonic stem cells for studies of neural plasticity and epigenetic control of glial and neural differentiation. Dr. Sammak is investigating the early stages of neural stem cell formation under various conditions and the control of differentiation by epigenetic (non-genetic) regulators including the histone deacetylases (HDACs). Differential expression of HDACs during glial formation may be an important regulators of directed fate selection. Nuclear reorganization is another epigenetic factor that controls neural cell fate. Nuclear plasticity and chromatin structure are especially dynamic in the pluripotent state but become progressively specified during early neural development. Understanding nuclear organization is an important aspect of neural regeneration after injury and may lead to improved ALS treatment by stimulating neural stem cell growth.  (see publications)



Figure Legend:

Differentiation of Neural and Glial Stem Cells from Human Embryonic Stem Cells.

hESC were treated with the BMP4 antagonist, noggin for 2 weeks and cells were stained with the neuron specific marker, ßIII tubulin (red), histone deacetylase 1 (green) and DNA (blue). Nascent neuronal lineages are negative for HDAC 1 (bottom left), while more glial and more primitive progenitors are positive for HDAC1 (top right).