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Paraquat (PQ) was demonstrated to induce dopaminergic neuron death and is used as a Parkinson's disease (PD) mimetic. Amounting evidences demonstrated that Rho/ROCK may a novel target for the therapy of PD. Previously we synthesized L-F001 and proved it is a potent ROCK inhibitor with multifunctional effects, including anti-oxidative stress. In this study, we investigated the effects and also the molecular mechanisms of L-F001 in preventing PQ-induced cytotoxicity in PC12 cells. L-F001 effectively prevented PQ-induced apoptotic cell death, which involves the scavenger of ROS and also attenuated the declined of mitochondrial membrane potential and intracellular level of GSH induced by PQ. Moreover, PQ quickly induced alterations of GRP78 and CHOP, two hallmarks of endoplasmic reticulum (ER) stress and subsequently induced dysfunction of the mitochondria (such as the decrease in membrane potential and increase in ROS). These changes all were potently attenuated by L-F001. In summary, L-F001 attenuated PQ-induced apoptosis through modulating mitochondrial dysfunction and ER stress as well as the ROS production elicited by PQ. These data indicated that L-F001 could possibly be used to treat PD and other neurodegenerative disorders with similar pathologic mechanisms.

Carvedilol, a nonselective β-adrenoreceptor blocker with pleiotropic activities has been shown to exert neuroprotective effect due to its antioxidant property. However, the neuroprotective mechanism of carvedilol is still not fully uncovered. Nuclear factor E2-related factor 2 (Nrf2)/antioxidant response element (ARE) pathway is an important cellular stress response pathway involved in neuroprotection. Here we investigated the effect of carvedilol on oxidative stress-induced cell death (glutamate 2mM and H2O2 600 μM) and the activity of Nrf2/ARE pathway in HT22 hippocampal cells. Carvedilol significantly increased cell viability and decreased ROS in HT22 cells exposed to glutamate or H2O2. Furthermore, carvedilol activated the Nrf2/ARE pathway in a concentration-dependent manner, and increased the protein levels of heme oxygenase-1(HO-1) and NAD(P)H quinone oxidoreductase-1(NQO-1), two downstream factors of the Nrf2/ARE pathway. Collectively, our results indicate that carvedilol protects neuronal cell against glutamate- and H2O2-induced neurotoxicity possibly through activating the Nrf2/ARE signaling pathway.

Copper (Cu(2+)) is an essential element for a variety of cellular functions; however, it is involved in neurotoxic events at excessive doses. Mechanisms of Cu(2+)-induced neurotoxicity are not well understood. Here, we studied the toxic effects of Cu(2+) on cultured cerebellar granule neurons (cCGNs). Treatment of cCGNs with CuCl(2) (50 and 75muM) caused a concentration- and time-dependent cell death with apoptotic characters, including chromatin condensation and DNA ladder. Cu(2+) potently induced reactive oxygen species (ROS), and quickly and slightly increased the intracellular concentration of calcium. Western blot assay showed that Cu(2+) increased phosphorylation of p38 mitogen-activated protein kinase (MAPK) and ERK1/2, but not that of JNK-1. Pharmacological inhibition of calcium influx, p38 MAPK and ERK1/2 attenuated the Cu(2+) toxicity in cCGNs. These findings demonstrate that p38 MAPK and ERK1/2, but not JNK, are involved in apoptosis of cCGNs induced by copper, and p38 and ERK may be the downstream effectors of ROS and calcium signaling.