title: Chaperonin GroEL and its mutant D87K protect from ischemia in vivo and in vitro.
abstract: Protein aggregation and misfolding are central mechanisms of both acute and chronic neurodegeneration. Overexpression of chaperone Hsp70 protects from stroke in animal and cell culture models. Although it is accepted that chaperones protect cells, the mechanism of protection by chaperones in ischemic injury is poorly understood. In particular, the relative importance of preventing protein aggregation compared to facilitating correct protein folding during ischemia and recovery is not known. To test the importance of protein folding and minimize interaction with co-chaperones we studied the bacterial chaperonin GroEL (HSPD1) and a folding-deficient mutant D87K. Both molecules protected cells from ischemia-like injury, and reduced infarct volume and improved neurological outcome after middle cerebral artery occlusion in rats. Protection was associated with reduced protein aggregation, assessed by ubiquitin immunohistochemistry. Marked neuroprotection by the folding-deficient chaperonin demonstrates that inhibition of aggregation is sufficient to protect the brain from ischemia. This suggests that strategies to maintain protein solubility and inhibit aggregation in the face of acute insults such as stroke may be a useful protective strategy.
authors.affiliation: Department of Anesthesia, Stanford University, Stanford, CA 94305, USA.
authors.forename: Lijun
authors.initials: L
authors.lastname: Xu
authors.forename: Manisha
authors.initials: M
authors.lastname: Dayal
authors.forename: Yi-Bing
authors.initials: YB
authors.lastname: Ouyang
authors.forename: Yunjuan
authors.initials: Y
authors.lastname: Sun
authors.forename: Chin Fen
authors.initials: CF
authors.lastname: Yang
authors.forename: Judith
authors.initials: J
authors.lastname: Frydman
authors.forename: Rona G
authors.initials: RG
authors.lastname: Giffard
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D000831:Animals, Newborn; D001224:Aspartic Acid / Q000235:genetics*; D001253:Astrocytes / Q000378:metabolism; D015153:Blotting, Western / Q000379:methods; D001921:Brain / Q000166:cytology / Q000473:pathology; D002449:Cell Aggregation / Q000235:genetics / Q000502:physiology; D002452:Cell Count / Q000379:methods; D016923:Cell Death / Q000502:physiology; D002478:Cells, Cultured; D018834:Chaperonin 60 / Q000008:administration & dosage / Q000235:genetics*; D006224:Cricetinae; D003412:Cricetulus; D005455:Fluorescent Antibody Technique / Q000379:methods; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D005947:Glucose / Q000172:deficiency; D006358:Hot Temperature / Q000009:adverse effects; D000860:Hypoxia / Q000150:complications / Q000209:etiology / Q000628:therapy; D066298:In Vitro Techniques; D020244:Infarction, Middle Cerebral Artery / Q000150:complications / Q000473:pathology / Q000628:therapy; D007511:Ischemia / Q000209:etiology / Q000473:pathology / Q000517:prevention & control*; D008239:Lysine / Q000235:genetics*; D051379:Mice; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D009154:Mutation / Q000502:physiology*; D009474:Neurons / Q000378:metabolism; D013778:Tetrazolium Salts; D013997:Time Factors; D014162:Transfection / Q000379:methods
chemical_list: D018834:Chaperonin 60; D005904:Glial Fibrillary Acidic Protein; D008869:Microtubule-Associated Proteins; C079240:Mtap2 protein, mouse; D013778:Tetrazolium Salts; D001224:Aspartic Acid; C009591:triphenyltetrazolium; D005947:Glucose; D008239:Lysine