Blockade of peroxynitrite-induced neural stem cell death in the acutely injured spinal cord by drug-releasing polymer.
Therapeutic impact of neural stem cells (NSCs) for acute spinal cord injury (SCI) has been limited by the rapid loss of donor cells. Neuroinflammation is likely the cause. As there are close temporal-spatial correlations between the inducible nitric oxide (NO) synthase expression and the donor NSC death after neurotrauma, we reasoned that NO-associated radical species might be the inflammatory effectors which eliminate NSC grafts and kill host neurons. To test this hypothesis, human NSCs (hNSCs: 5 x 10(4) to 2 x 10(6) per milliliter) were treated in vitro with "plain" medium, 20 microM glutamate, or donors of NO and peroxynitrite (ONOO(-); 100 and 400 microM of spermine or DETA NONOate, and SIN-1, respectively). hNSC apoptosis primarily resulted from SIN-1 treatment, showing ONOO(-)-triggered protein nitration and the activation of p38 MAPK, cytochrome c release, and caspases. Therefore, cell death following post-SCI (p.i.) NO surge may be mediated through conversion of NO into ONOO(-). We subsequently examined such causal relationship in a rat model of dual penetrating SCI using a retrievable design of poly-lactic-co-glycolic acid (PLGA) scaffold seeded with hNSCs that was shielded by drug-releasing polymer. Besides confirming the ONOO(-)-induced cell death signaling, we demonstrated that cotransplantation of PLGA film embedded with ONOO(-) scavenger, manganese (III) tetrakis (4-benzoic acid) porphyrin, or uric acid (1 micromol per film), markedly protected hNSCs 24 hours p.i. (total: n = 10). Our findings may provide a bioengineering approach for investigating mechanisms underlying the host microenvironment and donor NSC interaction and help formulate strategies for enhancing graft and host cell survival after SCI.
Yu
Dou
D
Department of Neurosurgery, Harvard Medical School, The Brigham and Women's Hospital and Children's Hospital Boston, Boston, MA 02115, USA.
Neeley
William L
WL
Pritchard
Christopher D
CD
Slotkin
Jonathan R
JR
Woodard
Eric J
EJ
Langer
Robert
R
Teng
Yang D
YD
D000208:Acute Disease; D000818:Animals; D017304:Annexin A5 / Q000378:metabolism; D015153:Blotting, Western; D020169:Caspases / Q000378:metabolism; D016923:Cell Death / Q000187:drug effects; D002460:Cell Line; D019610:Cytoprotection / Q000187:drug effects; D016503:Drug Delivery Systems; D004789:Enzyme Activation / Q000187:drug effects; D005452:Fluoresceins / Q000378:metabolism; D016166:Free Radical Scavengers / Q000008:administration & dosage* / Q000494:pharmacology; D006016:Glycolates / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry; D020287:In Situ Nick-End Labeling; D019344:Lactic Acid; D009474:Neurons / Q000166:cytology* / Q000187:drug effects; D009569:Nitric Oxide / Q000378:metabolism; D030421:Peroxynitrous Acid / Q000633:toxicity*; D011100:Polyglycolic Acid; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D051381:Rats; D015398:Signal Transduction; D013119:Spinal Cord Injuries / Q000473:pathology / Q000628:therapy*; D013234:Stem Cells / Q000166:cytology* / Q000187:drug effects; D014443:Tyrosine / Q000031:analogs & derivatives / Q000378:metabolism
D017304:Annexin A5; D005452:Fluoresceins; D016166:Free Radical Scavengers; D006016:Glycolates; C097499:fluorescein carboxylate; D030421:Peroxynitrous Acid; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D009569:Nitric Oxide; D019344:Lactic Acid; C002744:3-nitrotyrosine; D014443:Tyrosine; D020169:Caspases