Neuroglobin (Ngb) is a newly discovered globin in the vertebrate brain that exhibits neuroprotection against hypoxic/ischemic injury. Hypoxic/ischemic brain injury is associated with accumulation of reactive oxygen species (ROS) and/or reactive nitrogen species (RNS), and antioxidants or ROS scavengers promote cell survival. Therefore, Ngb may serve as a scavenger of toxic reactive species, such as hydrogen peroxide. To examine the anti-oxidative role of neuroglobin, PC12 cells were transfected with wild type and mutant (H64 V/H96A) Ngb for 48 h and then treated with H2O2 (0.1, 0.2 and 0.4 mM) for 6 h. Ngb siRNA decreased the H2O2-induced Ngb expression and exacerbated H2O2-induced cell injury. Transient transfection of Ngb induced dose-dependent increases in Ngb protein expression and did not alter SOD, GPX, and catalase activities. Overexpression of wild type Ngb, but not of mutant Ngb, significantly attenuated H2O2-induced ROS/RNS accumulation and lipid peroxidation, decreased H2O2-induced mitochondrial dysfunction and apoptosis, and promoted overall cell survival. Thus, Ngb plays a protective role against oxidative stress, which appears to be primarily mediated by intrinsic Ngb antioxidant properties.
Bibliographical noteFunding Information:
We thank Kenneth R. Brittian and Heather B. Clair for their expert technical assistance in cell culture and immunocytochemistry. This study was supported by National Institutes of Health grants SCOR 2P50-HL-60296 (Project 2) and RO1-HL-69932, The Children's Foundation Endowment for Sleep Research, and by the Commonwealth of Kentucky Challenge for Excellence Trust Fund.
- Oxidative stress
- PC12 cell
ASJC Scopus subject areas
- Molecular Biology
- Clinical Neurology
- Developmental Biology