Basic Study
Copyright ©The Author(s) 2016. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Biol Chem. Feb 26, 2016; 7(1): 168-177
Published online Feb 26, 2016. doi: 10.4331/wjbc.v7.i1.168
Arctic ground squirrel neuronal progenitor cells resist oxygen and glucose deprivation-induced death
Kelly L Drew, Matthew Wells, Rebecca McGee, Austin P Ross, Judith Kelleher-Andersson
Kelly L Drew, Austin P Ross, Institute of Arctic Biology, University of Alaska, Fairbanks, AK 99775, United States
Matthew Wells, Judith Kelleher-Andersson, Neuronascent, Inc., Clarksville, MD 21029, United States
Rebecca McGee, Lifeline Cell Technology, Frederick, MD 21701, United States
Author contributions: Drew KL, Wells M, McGee R and Kelleher-Anderson J contributed substantially to the conception and design of the study; Wells M, McGee R and Kelleher-Anderson J contributed substantially to data acquisition; Drew KL, Kelleher-Andersson J and Ross AP contributed substantially to the analysis and interpretation of data; all authors drafted the article and made critical revisions related to the intellectual content of the manuscript, and approved the final version of the article to be published.
Supported by The US Army Medical Research and Materiel Command, No. 05178001; the National Institute of Neurological Disorders and Stroke, Nos. NS041069-06 and R15NS070779.
Institutional review board statement: Not applicable.
Institutional animal care and use committee statement: Not applicable.
Conflict-of-interest statement: Two of the authors have financial interests in companies with commercial interests in neural stem cells isolated from the arctic ground squirrel. Kelleher-Andersson J works for Neuronascent, Inc. a Maryland Corporation. McGee R works for Lifeline Cell Technology, a subsidiary of International Stem Cell Corporation. Both companies shared commercial interest in AGS NSC. Kelleher-Andersson J owns stock in Neuronascent, Inc. McGee R holds stock options in International Stem Cell Corporation. Drew KL receives no financial support from Neuronascent, Inc. or Lifeline Cell Technology and has no other financial interests in AGS NSCs.
Data sharing statement: No other data are available.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Kelly L Drew, PhD, Institute of Arctic Biology, University of Alaska, 902 N. Koyukuk, STE 311, Fairbanks, AK 99775, United States. kdrew@alaska.edu
Telephone: +1-907-4747190 Fax: +1-907-4747666
Received: June 12, 2015
Peer-review started: June 16, 2015
First decision: September 17, 2015
Revised: December 19, 2015
Accepted: January 8, 2016
Article in press: January 11, 2016
Published online: February 26, 2016
Abstract

AIM: To investigate the influence of ischemia/reperfusion on arctic ground squirrel (AGS) neuronal progenitor cells (NPCs), we subjected these cultured cells to oxygen and glucose deprivation.

METHODS: AGS NPCs were expanded and differentiated into NPCs and as an ischemia vulnerable control, commercially available human NPCs (hNPCs) were seeded from thawed NPCs. NPCs, identified by expression of TUJ1 were seen at 14-21 d in vitro (DIV). Cultures were exposed to control conditions, hypoxia, oxygen and glucose deprivation or glucose deprivation alone or following return to normal conditions to model reperfusion. Cell viability and death were assessed from loss of ATP as well as from measures of alamarBlue® and lactate dehydrogenase in the media and from counts of TUJ1 positive cells using immunocytochemistry. Dividing cells were identified by expression of Ki67 and phenotyped by double labeling with GFAP, MAP2ab or TUJ1.

RESULTS: We report that when cultured in NeuraLife™, AGS cells remain viable out to 21 DIV, continue to express TUJ1 and begin to express MAP2ab. Viability of hNPCs assessed by fluorescence alamarBlue (arbitrary units) depends on both glucose and oxygen availability [viability of hNPCs after 24 h oxygen glucose deprivation (OGD) with return of oxygen and glucose decreased from 48151 ± 4551 in control cultures to 43481 ± 2413 after OGD, P < 0.05]. By contrast, when AGS NPCs are exposed to the same OGD with reperfusion at 14 DIV, cell viability assessed by alamarBlue increased from 165305 ± 11719 in control cultures to 196054 ± 13977 after OGD. Likewise AGS NPCs recovered ATP (92766 ± 6089 in control and 92907 ± 4290 after modeled reperfusion; arbitrary luminescence units), and doubled in the ratio of TUJ1 expressing neurons to total dividing cells (0.11 ± 0.04 in control cultures vs 0.22 ± 0.2 after modeled reperfusion, P < 0.05). Maintaining AGS NPCs for a longer time in culture lowered resistance to injury, however, did not impair proliferation of NPCs relative to other cell lineages after oxygen deprivation followed by re-oxygenation.

CONCLUSION: Ischemic-like insults decrease viability and increase cell death in cultures of human NPCs. Similar conditions have less affect on cell death and promote proliferation in AGS NPCs.

Keywords: Neurogenesis, Neuronal progenitor, Hypoxia tolerance, Hibernation

Core tip: Cultured arctic ground squirrel (AGS) neuronal progenitor cells (NPCs) resist cell death under conditions designed to model ischemia/reperfusion and instead show evidence of proliferation. Persistence of progenitor properties and hence the capacity to divide is a unique characteristic of AGS NPCs. Mechanisms that prolong neuronal progenitor properties may be targets to increase tolerance to cerebral ischemia/reperfusion in humans at risk of stroke and cardiac arrest.