title: Beneficial effects of carbamylated erythropoietin against oxygen-glucose deprivation/reperfusion-induced astrocyte swelling: proposed molecular mechanisms of action.
abstract: Carbamylated erythropoietin (C-EPO), one of the erythropoietin derivatives, retains strong anti-edema and neuroprotective properties while lacking the hematopoietic complications of erythropoietin. This study investigated the intracellular and molecular mechanisms underlying the anti-edema property of C-EPO. An in vitro model of astrocyte swelling was created by 5h of oxygen-glucose deprivation and subsequent reperfusion (OGD/Rep). Astrocyte cultures were then treated with C-EPO or left as control cells. Here we show that increases in astrocyte volume, morphological cell swelling, and changes in ultrastructure after OGD/Rep were significantly mitigated by treatment with C-EPO (10 ng/ml). The decreases in AQP-4 phosphorylation after OGD/Rep were remarkably recovered by C-EPO treatment. The OGD/Rep-induced upregulations of AQP-4 mRNA and protein were also prevented by C-EPO treatment. Additional treatment with phorbol myristate acetate, an activator of protein kinase C (PKC), enhanced C-EPO-mediated neuroprotective effects, while that of H-7, an inhibitor of PKC, blocked these protections. Our findings establish that C-EPO effectively mitigates astrocyte swelling induced by ischemia and reperfusion-like injury. The modulation of AQP-4 phosphorylation and expression via the PKC pathway is participated in the neuroprotective effects of C-EPO.
authors.affiliation: Department of Neurosurgery, the First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, China.
authors.forename: Zhaohua
authors.initials: Z
authors.lastname: Tang
authors.forename: Xiaochuan
authors.initials: X
authors.lastname: Sun
authors.forename: Quanhong
authors.initials: Q
authors.lastname: Shi
authors.forename: Xiaoshu
authors.initials: X
authors.lastname: Wang
authors.forename: Yanfeng
authors.initials: Y
authors.lastname: Xie
authors.forename: Gang
authors.initials: G
authors.lastname: Huo
authors.forename: Shuai
authors.initials: S
authors.lastname: Zhou
authors.forename: Zhengbu
authors.initials: Z
authors.lastname: Liao
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D051401:Aquaporin 4 / Q000378:metabolism; D001253:Astrocytes / Q000187:drug effects* / Q000378:metabolism / Q000648:ultrastructure; D001929:Brain Edema / Q000188:drug therapy* / Q000378:metabolism; D004921:Erythropoietin / Q000031:analogs & derivatives* / Q000494:pharmacology; D005947:Glucose / Q000494:pharmacology*; D008854:Microscopy, Electron; D018696:Neuroprotective Agents / Q000494:pharmacology; D010100:Oxygen / Q000494:pharmacology*; D010766:Phosphorylation / Q000187:drug effects / Q000502:physiology; D061251:Primary Cell Culture; D011493:Protein Kinase C / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D015427:Reperfusion Injury / Q000188:drug therapy / Q000378:metabolism
chemical_list: C496032:Aqp4 protein, rat; D051401:Aquaporin 4; D018696:Neuroprotective Agents; C488171:carbamylated erythropoietin; D004921:Erythropoietin; D011493:Protein Kinase C; D005947:Glucose; D010100:Oxygen