calpain and Cerebrovascular-Disorders

Topics: Animals; Brain; Brain Ischemia; Calcium; Calpain; Cerebrovascular Circulation; Cerebrovascular Disorders; Humans; Ischemic Attack, Transient; Neurons; Neuroprotective Agents

Topics: Adenosine Triphosphate; Animals; Apoptosis; Brain Ischemia; Calpain; Caspase 3; Cerebral Arteries; Cerebrovascular Disorders; Culture Media; Disks Large Homolog 4 Protein; Gene Expression Regulation; Glucose; Hippocampus; Humans; Intracellular Signaling Peptides and Proteins; Memantine; Membrane Proteins; Microtubule-Associated Proteins; Neurons; Neuroprotective Agents; Primary Cell Culture; Rats; Rats, Sprague-Dawley; Signal Transduction; Stroke

The 94 kDa glucose-regulated protein (GRP94), the endoplasmic reticulum (ER) resident molecular chaperone, has a role in cell death due to endoplasmic reticulum stress (ER stress). Here, we report that expression of GRP94 was increased in human neuroblastoma cells (SH-SY5Y (SY5Y) cells) exposed to hypoxia/reoxygenation (H/R). H/R mediated death of SY5Y cells was associated with the activation of major cysteine proteases, caspase-3 and calpain, along with an elevated intracellular calcium concentration. Pretreatment with adenovirus-mediated antisense GRP94 (AdGRP94AS) led to reduced viability of SY5Y cells after being subjected to H/R compared with wild-type cells or cells with adenovirus-mediated overexpression of GRP94 (AdGRP94S). These results indicate that suppression of GRP94 is associated with accelerated apoptosis and that expression of GRP94 (as a stress protein) suppresses oxidative stress-mediated neuronal death and stabilizes calcium homeostasis in the ER. We also used gerbils with transient forebrain ischemia to study the role of GRP94 in vivo. Neurons with adenovirus-mediated overexpression of GRP94 were resistant to ischemic damage. These results confirmed that GRP94 could suppress ischemic injury to neurons, suggesting that gene transfer of GRP94 into the brain may have therapeutic potential in the treatment of cerebrovascular disease.

Topics: Animals; Apoptosis; Calcium; Calpain; Caspase 3; Caspases; Cell Survival; Cerebrovascular Disorders; Cysteine Endopeptidases; DNA, Recombinant; Endoplasmic Reticulum; Gene Transfer Techniques; Gerbillinae; HSP70 Heat-Shock Proteins; Humans; Immunoblotting; Immunohistochemistry; In Situ Nick-End Labeling; Membrane Proteins; Models, Animal; Neuroblastoma; Neurons; Reperfusion Injury; Tumor Cells, Cultured

Drs. John Elce and Peter Davies, biochemists at Queen's University, Kingston, Ont., are investigating the molecular structure of calpain, an enzyme that has been implicated in the cellular damage that occurs after such events as myocardial infarction and stroke. This damage is precipitated by an imbalance in the regulation of calpain that arises as an indirect result of ischemia. Elce and Davies hope that their research, which involves techniques such as recombinant DNA technology and x-ray crystallography, will lead to the development of a calpain inhibitor that will prevent such damage from occurring and enhance recovery.

Topics: Calpain; Cerebrovascular Disorders; Humans; Myocardial Infarction