"We are interested in the development of the nervous system
and continued neurogenesis from stem cells in the adult."

Carbon dating human cells

Biomedical research has progressed enormously over the last few decades, and we now understand many biological processes in minute detail at the molecular level. Nevertheless, there are a few fundamental processes that have remained very difficult to study and where our knowledge is scant. One of those is cell turnover in the human body, and in particular neuronal turnover in the adult human brain.Given the accumulating wealth of animal data, it is remarkable how little is actually known about whether we have new nerve cells added to our brain in adulthood. For this reason we are interested in developing a technique where we could look at cell turnover as it occurs in humans. In order to do this, we take advantage of a geophysical event (above ground nuclear bomb testing) and advances in biophysics (the development of accelerator mass spectrometry, AMS) to develop a novel method where we can retrospectively determine the age of a population of cells.

Ephrins and Eph Receptors

During the development of the nervous system, axons grow over large distances with high precision to connect with their targets. Ephrins are membrane anchored proteins which can guide extending axons by repulsion. Graded expression of ephrins and their Eph receptors in certain regions of the nervous system direct the formation of topographic maps in the nervous system. In addition to guiding growing axons, ephrin-A5 participates in neurulation. We are interested in further characterizing the role of ephrins and Eph receptors in the developing nervous system, as well as understanding how these molecules can mediate such diverse effects as axon repulsion and fusion of the neural tube.

Neural Stem Cells

For a long time it was believed that neurogenesis in the mammalian central nervous system was restricted to the embryonic and early postnatal period. It is now well established that new neurons are generated continuously in adult mammals including man. These neurons derive from self-renewing multipotent neural stem cells. We have recently demonstrated that ependymal cells have stem cell properties, that they generate neurons in the intact brain and that they give rise to astrocytes which contribute to scar formation after injury. Current projects aim to further characterize adult CNS stem cells and to develop strategies to direct their differentiation to neuronal types that may be utilized for replacement therapies in experimental models of neurodegenerative diseases.



the Frisén Lab, Karolinska Institute, CMB, Box 285, 171 77 Stockholm. Visiting address: Berzelius väg 35 
Tel & E-mail info: Click here.