Ca2+ signals regulate diverse functions in the developing nervous system, including proliferation and differentiation of neural stem cells (NSCs), migration of nascent neurons, and apoptosis. Although the role of Ca2+ signaling in the development of the nervous system is widely recognized, little is known about the mechanisms responsible for the production of Ca2+ signals in NSCs. Among the various mechanisms by which cellular Ca2+ signals are generated, store-operated Ca2+ release-activated Ca2+ (CRAC) channels have emerged as a widespread pathway for regulating many Ca2+-dependent functions, including transcription, motility and proliferation. CRAC channels are encoded by the Orai genes, which give rise to three highly homologous proteins that are widely expressed in most tissues. Emerging evidence in our laboratory indicates that CRAC channels arising from the canonical Orai1-STIM1 proteins comprise a major route of Ca2+ entry in NSCs. Moreover, we find that Ca2+ influx through CRAC channels powerfully activates Ca2+-dependent gene expression through the transcription factor, NFAT, and regulates proliferation of NSCs. We hypothesize that CRAC channels are a key checkpoint for regulating gene expression, self-renewal, and differentiation of neural progenitors. The overall thrust of the present proposal is to elucidate the molecular and functional properties of CRAC channels in NSCs and illuminate their role for gene expression, proliferation, and differentiation of NSCs. Using a powerful combination of optical, electrophysiological and biochemical approaches as well as genetically engineered mice lacking CRAC channel function, we will: 1) define the electrophysiological properties and molecular machinery of CRAC channels in NSCs, 2) investigate the physiological activators of CRAC channels in NSCs, and, 3) illuminate the downstream functions of CRAC channels for gene expression, proliferation, and lineage commitment. Findings from these studies will reveal the role of an important yet unexplored Ca2+ signaling pathway for the biology of NSCs, and facilitate strategies to develop therapeutics based on the engineering of neural stems cells for neurodegenerative diseases and brain trauma.

Public Health Relevance

Store-operated CRAC channels mediate vital functions in several cell types including immune, muscle, and other tissues, but their role in the nervous system remains unknown. The goal of this project is to understand the physiological role of CRAC channels in neural stem cells. Findings from these studies will illuminate how gene expression, self-renewal, and lineage commitment of neural stem cells are controlled and contribute to the development of stem-cell based therapeutic strategies to treat brain injuries and neurodegenerative diseases.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS057499-07
Application #
8586563
Study Section
Neurotransporters, Receptors, and Calcium Signaling Study Section (NTRC)
Program Officer
Stewart, Randall R
Project Start
2007-02-13
Project End
2016-12-31
Budget Start
2014-01-01
Budget End
2014-12-31
Support Year
7
Fiscal Year
2014
Total Cost
$335,720
Indirect Cost
$115,360
Name
Northwestern University at Chicago
Department
Pharmacology
Type
Schools of Medicine
DUNS #
005436803
City
Chicago
State
IL
Country
United States
Zip Code
60611
Yamashita, Megumi; Prakriya, Murali (2014) Divergence of Ca(2+) selectivity and equilibrium Ca(2+) blockade in a Ca(2+) release-activated Ca(2+) channel. J Gen Physiol 143:325-43
Somasundaram, Agila; Shum, Andrew K; McBride, Helen J et al. (2014) Store-operated CRAC channels regulate gene expression and proliferation in neural progenitor cells. J Neurosci 34:9107-23
Prakriya, Murali (2013) Store-operated Orai channels: structure and function. Curr Top Membr 71:1-32
Jairaman, Amit; Prakriya, Murali (2013) Molecular pharmacology of store-operated CRAC channels. Channels (Austin) 7:
McNally, Beth A; Somasundaram, Agila; Jairaman, Amit et al. (2013) The C- and N-terminal STIM1 binding sites on Orai1 are required for both trapping and gating CRAC channels. J Physiol 591:2833-50
Hobbs, Ryan P; Amargo, Evangeline V; Somasundaram, Agila et al. (2011) The calcium ATPase SERCA2 regulates desmoplakin dynamics and intercellular adhesive strength through modulation of PKCα signaling. FASEB J 25:990-1001
Gusarova, Galina A; Trejo, Humberto E; Dada, Laura A et al. (2011) Hypoxia leads to Na,K-ATPase downregulation via Ca(2+) release-activated Ca(2+) channels and AMPK activation. Mol Cell Biol 31:3546-56
Yamashita, Megumi; Somasundaram, Agila; Prakriya, Murali (2011) Competitive modulation of Ca2+ release-activated Ca2+ channel gating by STIM1 and 2-aminoethyldiphenyl borate. J Biol Chem 286:9429-42
Mungai, Paul T; Waypa, Gregory B; Jairaman, Amit et al. (2011) Hypoxia triggers AMPK activation through reactive oxygen species-mediated activation of calcium release-activated calcium channels. Mol Cell Biol 31:3531-45
McCarl, Christie-Ann; Khalil, Sara; Ma, Jian et al. (2010) Store-operated Ca2+ entry through ORAI1 is critical for T cell-mediated autoimmunity and allograft rejection. J Immunol 185:5845-58

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