TAT-mediated delivery of neuroglobin attenuates apoptosis induced by oxygen-glucose deprivation via the Jak2/Stat3 pathway in vitro.Neurol Res. 2015 Jun; 37(6):531-8.NR
Neuroglobin (Ngb), an identified globin in vertebrate brain, is a potential novel protective protein against brain ischemia. In our previous study, the human immunodeficiency virus trans-activator of transcription (TAT) protein transduction domain successfully delivered exogenous Ngb into neurons in the mouse, and protected the brain from cerebral ischemia-induced apoptosis. The aim of this study is to investigate the role of TAT-Ngb in attenuating oxygen-glucose deprivation (OGD) induced apoptosis and to explore the possible mechanism.
Nerve growth factor (NGF)-induced PC12 cells were divided into (1) the control group, (2) the OGD group (just OGD), (3) the Ngb treatment group (OGD and Ngb treatment), and (4) the TAT-Ngb treatment group (OGD and TAT-Ngb treatment). Cell viability and apoptosis were assessed by the MTT assay and the AnnexinV/propidium iodide (PI) staining, respectively. The mitochondrial transmembrane potential was measured by JC-1 staining. Caspase-3, Bcl-2, Bax, Stat3, Jak2, and Akt were determined by western blot analysis.
Trans-activator of transcription effectively delivered Ngb into NGF-induced PC12 cells. Neuroglobin-mediated neuroprotection rescued cultured cells from OGD. We also confirmed previous findings that TAT-Ngb inhibited mitochondrial apoptosis following OGD. Inhibition of apoptosis by Ac-DEVD-CHO showed that caspase-3 was a crucial factor in OGD-induced apoptosis cascades. AG490, a specific Jak2 inhibitor, attenuated the protective effects of TAT-Ngb. The TAT-Ngb promoted expression of the anti-apoptotic protein Bcl-2 through the Jak2/Stat3 signal pathway, and inhibited apoptosis by blocking caspase-3 activation, while the Jak-Akt-Stat3 signal network was not involved.
Our results demonstrate that TAT-Ngb can protect neuron-like cells against OGD-induced apoptosis by activating the Jak2/Stat3 pathway.