Identification and characterization of a population of motile neurons in long-term cortical culture

• Published in: Cell motility and the cytoskeleton Vol. 64; no. 4; pp. 274 - 287
• Main Authors: Haas, Matilda A., Chuckowree, Jyoti A., Chung, Roger S., Vickers, James C., Dickson, Tracey C.
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 01-04-2007
• Subjects: Animals; Body Patterning - genetics; Bromodeoxyuridine - metabolism; Cell Culture Techniques; Cell Differentiation - physiology; Cell Movement - drug effects; Cell Movement - physiology; Cerebral Cortex - cytology; Cerebral Cortex - drug effects; Cerebral Cortex - metabolism; cytoskeleton; Cytoskeleton - physiology; Growth Cones - ultrastructure; Immunohistochemistry - methods; Microtubules - drug effects; migration; molecular guidance cues; Nerve Growth Factors - physiology; Neurons - cytology; Neurons - drug effects; Neurons - metabolism; nocodazole; Nocodazole - pharmacology; Rats; Rats, Wistar; taxol
• ISSN: 0886-1544; 1097-0169
• DOI: 10.1002/cm.20182

The specific phenotypes and progression to maturity of primary cortical neurons in long‐term culture correlate well with neurons in vivo. Utilizing a model of neuronal injury in long‐term cultures at 21 days in vitro (DIV), we have identified a distinct population of neurons that translocate into the injury site. 5‐Bromo‐2′‐deoxyUridine (BrdU) incorporation studies demonstrated that neurons with the capacity to translocate were 21 days old. However, this motile ability is not consistent with the traditional view of the maturation and structural stability of neurons in long‐term culture. Therefore, we examined the neurons' cytoskeletal profile using immunocytochemistry, to establish relative stage of maturation and phenotype. Expression of marker proteins including β‐III‐tubulin, α‐internexin, NF‐L and NF‐M, tau and L1 indicated the neurons were differentiated, and in some cases polarized. The neurons did not immunolabel with NF‐H or MAP2, which might suggest they had not reached the level of maturity of other neurons in culture. They did not express the microtubule‐associated migration marker doublecortin (DCX). Cytoskeletal disrupting agents were used to further investigate the role of the microtubule cytoskeleton in translocation, and microtubule destabilization significantly enhanced aspects of their motility. Finally, molecular guidance cues affected their motility in a similar manner to that reported for both axon guidance and early neuron migration. Therefore, this study has identified and characterized a population of motile neurons in vitro that have the capacity to migrate into a site of injury. These studies provide new information on the structurally dynamic features of subsets of neurons. Cell Motil. Cytoskeleton 2007. © 2006 Wiley‐Liss, Inc.