Hydrogen sulfide protects against chemical hypoxia-induced injury by inhibiting ROS-activated ERK1/2 and p38mapk signaling pathways in PC12 cells

Abstract

Hydrogen sulfide (H 2S) has been proposed as a novel neuromodulator and neuroprotective agent. Cobalt chloride (CoCl 2) is a well-known hypoxia mimetic agent. We have demonstrated that H 2S protects against CoCl 2-induced injuries in PC12 cells. However, whether the members of mitogen-activated protein kinases (MAPK), in particular, extracellular signal-regulated kinase1/2(ERK1/2) and p38MAPK are involved in the neuroprotection of H 2S against chemical hypoxia-induced injuries of PC12 cells is not understood. We observed that CoCl 2 induced expression of transcriptional factor hypoxia-inducible factor-1 alpha (HIF-1α), decreased cystathionine-β synthase (CBS, a synthase of H 2S) expression, and increased generation of reactive oxygen species (ROS), leading to injuries of the cells, evidenced by decrease in cell viability, dissipation of mitochondrial membrane potential (MMP), caspase-3 activation and apoptosis, which were attenuated by pretreatment with NaHS (a donor of H 2S) or N-acetyl-L cystein (NAC), a ROS scavenger. CoCl 2 rapidly activated ERK1/2, p38MAPK and C-Jun N-terminal kinase (JNK). Inhibition of ERK1/2 or p38MAPK or JNK with kinase inhibitors (U0126 or SB203580 or SP600125, respectively) or genetic silencing of ERK1/2 or p38MAPK by RNAi (Si-ERK1/2 or Si-p38MAPK) significantly prevented CoCl 2-induced injuries. Pretreatment with NaHS or NAC inhibited not only CoCl 2-induced ROS production, but also phosphorylation of ERK1/2 and p38MAPK. Thus, we demonstrated that a concurrent activation of ERK1/2, p38MAPK and JNK participates in CoCl 2-induced injuries and that H 2S protects PC12 cells against chemical hypoxia-induced injuries by inhibition of ROS-activated ERK1/2 and p38MAPK pathways. Our results suggest that inhibitors of ERK1/2, p38MAPK and JNK or antioxidants may be useful for preventing and treating hypoxia-induced neuronal injury. © 2011 Lan et al.