cytochrome-c-t and salubrinal

Cardiac arrest (CA) yields poor neurological outcomes. Salubrinal (Sal), an endoplasmic reticulum (ER) stress inhibitor, has been shown to have neuroprotective effects in both in vivo and in vitro brain injury models. This study investigated the neuroprotective mechanisms of Sal in postresuscitation brain damage in a rodent model of CA. In the present study, rats were subjected to 6 min of CA and then successfully resuscitated. Either Sal (1 mg/kg) or vehicle (DMSO) was injected blindly 30 min before the induction of CA. Neurological status was assessed 24 h after CA, and the cortex was collected for analysis. As a result, we observed that, compared with the vehicle-treated animals, the rats pretreated with Sal exhibited markedly improved neurological performance and cortical mitochondrial morphology 24 h after CA. Moreover, Sal pretreatment was associated with the following: (1) upregulation of superoxide dismutase activity and a reduction in maleic dialdehyde content; (2) preserved mitochondrial membrane potential; (3) amelioration of the abnormal distribution of cytochrome C; and (4) an increased Bcl-2/Bax ratio, decreased cleaved caspase 3 upregulation, and enhanced HIF-1

Topics: Aldehydes; Animals; Apoptosis; Brain Injuries; Cardiopulmonary Resuscitation; Caspase 3; Cerebellar Cortex; Cinnamates; Cytochromes c; Endoplasmic Reticulum Stress; Heart Arrest; Hypoxia-Inducible Factor 1, alpha Subunit; Male; Membrane Potential, Mitochondrial; Microscopy, Electron, Transmission; Mitochondria; Neuroprotective Agents; Proto-Oncogene Proteins c-bcl-2; Rats; Rats, Sprague-Dawley; Superoxide Dismutase-1; Thiourea

Sarsasapogenin is a sapogenin from the Chinese medical herb Anemarrhena asphodeloides Bunge. In the present study, we revealed that sarsasapogenin exhibited antitumor activity by inducing apoptosis in vitro as determined by Hoechst staining analysis and double staining of Annexin V-FITC/PI. In addition, cell cycle arrest in G2/M phase was observed in sarsasapogenin-treated HeLa cells. Moreover, the results revealed that perturbations in the mitochondrial membrane were associated with the deregulation of the Bax/Bcl-2 ratio which led to the upregulation of cytochrome c, followed by activation of caspases. Meanwhile, treatment of sarsasapogenin also activated Unfolded Protein Response (UPR) signaling pathways and these changes were accompanied by increased expression of CHOP. Salubrinal (Sal), a selective inhibitor of endoplasmic reticulum (ER) stress, partially abrogated the sarsasapogenin-related cell death. Furthermore, sarsasapogenin provoked the generation of reactive oxygen species, while the antioxidant N-acetyl cysteine (NAC) effectively blocked the activation of ER stress and apoptosis, suggesting that sarsasapogenin-induced reactive oxygen species is an early event that triggers ER stress mitochondrial apoptotic pathways. Taken together, the results demonstrate that sarsasapogenin exerts its antitumor activity through both reactive oxygen species (ROS)-mediate mitochondrial dysfunction and ER stress cell death.

Topics: Anemarrhena; Antineoplastic Agents; bcl-2-Associated X Protein; Cell Cycle Checkpoints; Cinnamates; Cytochromes c; Drugs, Chinese Herbal; Endoplasmic Reticulum Stress; Female; G1 Phase Cell Cycle Checkpoints; HeLa Cells; Humans; M Phase Cell Cycle Checkpoints; Mitochondria; Mitochondrial Membranes; Reactive Oxygen Species; Spirostans; Thiourea; Transcription Factor CHOP; Unfolded Protein Response; Uterine Cervical Neoplasms

Salubrinal is a specific eIF2α phosphatase inhibitor that inhibits ER stress-mediated apoptosis. However, maintaining hyper-phosphorylated eIF2α state with high doses of salubrinal treatment promotes apoptosis in some cancer cells. In this report, we found that salubrinal induced apoptosis of EBV-transformed B cells. Notably, salubrinal induced ROS generation and p38 MPAK activation, which then induced expression of FasL. Moreover, salubrinal subsequently led to activation of caspases, calcium redistribution, Bax translocation, cytochrome c release, and apoptosis. These findings suggest that salubrinal may be a novel therapeutic approach for EBV-associated malignant diseases.

Topics: Animals; Apoptosis; B-Lymphocytes; bcl-2-Associated X Protein; bcl-Associated Death Protein; bcl-X Protein; BH3 Interacting Domain Death Agonist Protein; Calcium; Caspases; Cell Line, Transformed; Cinnamates; Cytochromes c; Endoplasmic Reticulum; Eukaryotic Initiation Factor-2B; Fas Ligand Protein; Herpesvirus 4, Human; Mitochondria; p38 Mitogen-Activated Protein Kinases; Protein Transport; Reactive Oxygen Species; Thiourea