title: Melatonin attenuates decrease of protein phosphatase 2A subunit B in ischemic brain injury.
abstract: Melatonin is an antioxidant that has neuroprotective functions in ischemic brain injury. Protein phosphatase 2A (PP2A) is a serine and threonine phosphatase that modulates cell metabolism and cell survival. This study investigated whether melatonin modulates PP2A subunit B in focal cerebral ischemia and glutamate toxicity-induced neuronal cell death in a rat model. Middle cerebral artery occlusion (MCAO) was performed to induce permanent cerebral ischemic injury. Adult male rats were treated with vehicle or melatonin (5 mg/kg) prior to MCAO, and cerebral cortex tissues were collected 24 hr after MCAO. A proteomic approach elucidated the decrease in PP2A subunit B in MCAO-operated animals. Melatonin treatment attenuated injury-induced reductions in PP2A subunit B levels. Western blot analyses indicated that melatonin prevents injury-induced decrease in PP2A subunit B levels. In neuronal cells, glutamate toxicity induced a lowering of PP2A subunit B, while melatonin treatment attenuated the glutamate exposure-induced decreases in PP2A subunit B. These results suggest that the maintenance of PP2A subunit B by melatonin in ischemic injury is critical to the neuroprotective function of melatonin during neuronal cell damage.
authors.affiliation: Department of Anatomy, College of Veterinary Medicine and Research Institute of Life Science, Gyeongsang National University, Jinju, South Korea. pokoh@gnu.ac.kr
authors.forename: Phil-Ok
authors.initials: PO
authors.lastname: Koh
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001921:Brain / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D001923:Brain Chemistry; D002545:Brain Ischemia / Q000188:drug therapy* / Q000201:enzymology*; D002352:Carrier Proteins / Q000378:metabolism*; D002460:Cell Line; D007150:Immunohistochemistry; D008297:Male; D008550:Melatonin / Q000494:pharmacology*; D018696:Neuroprotective Agents / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D002352:Carrier Proteins; D018696:Neuroprotective Agents; C538792:PPP2R2B protein, rat; D008550:Melatonin