Neural Stem Cells

CRAC channel function and calcium dynamics in neural stem cells
2012 Seed Grant
Murali Prakriya, Ph.D.
Department of Molecular Pharmacology and Biological Chemistry
Northwestern University

Dr. Prakriya will use his 2012 Seed Grant to illuminate the calcium signaling mechanisms regulating the development of neural stem cells.  Specifically, the Prakriya lab will investigate the hypothesis that ion channel pores called calcium release-activated calcium (CRAC) channels serve as a key route of calcium entry in neural stem cells. Test of this hypothesis would help resolve a long-standing mystery in neuronal development, suggest novel therapeutic solutions for neurodegenerative diseases and brain trauma, and lay a sound foundation on which to build, and finance, the long-term plan for this research.

Early neuronal development involves extensive proliferation of cells in an embryonic tissue known as the neuroepithelium, which is comprised of specialized ‘neural stem cells.’ During prenatal development, these cells divide furiously to generate the billions of neurons, astrocytes, and other glial cells that populate the brain. As these events unfold, rhythmic bursts of intracellular calcium (Ca2+) signals influence the ultimate developmental fates of the neural stem cells. Ca2+ is a common signaling molecule that is employed by virtually all eukaryotic cells to control the activity of many enzymes and proteins. The bursts of Ca2+ signals in neural stem cells during embryonic development encode information in a kind of biological Morse code to regulate myraid enzymes and genetic programs that influence neural development. Yet, the mechanisms by which Ca2+ signals are generated in the NSCs, and specifically, the proteins that permit the entry of Ca2+ into neural stem cells remains a major mystery. Resolving this question is important not only for deepening our understanding of the molecular players that orchestrate neural development, but also because identifying the Ca2+ entry pathways could provide leads to manipulate Ca2+ signaling for therapeutic interventions.

In seeking to solve this puzzle, Dr. Prakriya’s lab has determined that CRAC channels serve as a major route of Ca2+ entry in neural stem cells. Although it is known that CRAC channels are expressed in the brain, their cellular functions have remained poorly defined. Elucidating the role of this newly discovered signaling pathway in the brain could illuminate the mechanisms that control neural development and open up novel strategies for therapeutic interventions. In this project, he will employ a powerful combination of electrophysiology (to examine CRAC channel activity), microscopy (to visualize the sub-cellular localization of CRAC channel proteins), and genetic approaches (to manipulate CRAC channel function) to investigate two fundamental questions. First, they will determine which CRAC channels are expressed in different types of mouse neural stem cells (embryonic, adult, and cultured). The key molecular components of this pathway will be elucidated using neural stem cells derived from mice lacking specific CRAC channel proteins. This information will provide a solid framework for understanding the cellular functions of CRAC channels in neural stem cells.  Second, they will investigate the functional properties and physiological contributions of CRAC channels by suppressing CRAC channel function and examining the consequences for key downstream cellular functions such as gene expression and the proliferation of neural stem cells. Collectively, the findings from these studies will reveal the role of an important yet unexplored Ca2+ signaling pathway for the biology of neural stem cells. In addition, the findings will provide the framework to design novel therapeutics based on the engineering of neural stem cells for treating traumatic brain injuries and neurodegenerative diseases such as Alzheimer’s disease.

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