title: Heat shock protein 90 mediates cytoprotection by H₂S against chemical hypoxia-induced injury in PC12 cells.
abstract: 1. Increasing evidence indicates that hydrogen sulphide (H₂S) may serve as an important biological cytoprotective agent. Heat shock protein (Hsp) 90 can attenuate stress-induced injury. However, whether Hsp90 mediates the cytoprotective effect of H₂S against chemical hypoxia-induced injury in PC12 cells is not known. 2. In the present study, CoCl₂ (a chemical hypoxia mimetic) was used to treat PC12 cells to create a model of chemical hypoxia. To explore the role of Hsp90 in the cytoprotection afforded by H₂S against chemical hypoxia-induced injury, 2 μmol/L 17-allylaminogeldanamycin (17-AAG), a selective inhibitor of Hsp90, was administered for 30 min prior to preconditioning with 400 μmol/L NaHS, followed by chemical hypoxia. 3. Cobalt chloride reduced cell viability (by 52.7 ± 1.5%), increased PC12 cell apoptosis (by 42.1 ± 1.5%), induced reactive oxygen species (ROS) by 3.79% compared with control and induced the dissipation of mitochondrial membrane potential (MMP) by 2.56% compared with control. 4. Pretreatment of PC12 cells with 100-400 μmol/L sodium hydrosulphide (NaHS), an H₂S donor, for 3 h prior to exposure to 600 μmol/L CoCl₂ provided significant, concentration-dependant protection to PC12 cells against CoCl₂-induced cytotoxicity. Specifically, pretreatment of PC12 cells with 400 μmol/L NaHS decreased apoptosis to 16.77 ± 1.77% and blocked the CoCl₂-induced increase in ROS production and loss of MMP. 5. At 400 μmol/L, NaHS upregulated Hsp90 in a time-dependant manner (over the period 0-180 min). In addition to its effects on Hsp90 expression, NaHS pretreatment of PC12 cells augmented the overexpression of Hsp90 induced by 600 μmol/L CoCl₂ by 1.38-fold (P < 0.01). 6. Treatment of PC12 cells with 2 μmol/L 17-AAG for 30 min prior to NaHS pretreatment blocked the overexpression of Hsp90 induced by NaHS preconditioning, as evidenced by decreased cell viability (by 54.2 + 1.2%; P < 0.01), increased PC12 cell apoptosis (by 36.6 ± 1.2%; P < 0.01) and increasing ROS production. 7. The findings of the present study provide novel evidence that Hsp90 mediates H₂S-induced neuroprotection against chemical hypoxia-induced injury via anti-oxidant and anti-apoptotic effects.
authors.affiliation: Department of Physiology, Zhongshan Medical College, China.
authors.forename: Jin-Lan
authors.initials: JL
authors.lastname: Meng
authors.forename: Wei-Yi
authors.initials: WY
authors.lastname: Mei
authors.forename: Yan-Fen
authors.initials: YF
authors.lastname: Dong
authors.forename: Jian-Hong
authors.initials: JH
authors.lastname: Wang
authors.forename: Chun-Mei
authors.initials: CM
authors.lastname: Zhao
authors.forename: Ai-Ping
authors.initials: AP
authors.lastname: Lan
authors.forename: Chun-Tao
authors.initials: CT
authors.lastname: Yang
authors.forename: Pei-Xi
authors.initials: PX
authors.lastname: Chen
authors.forename: Jian-Qiang
authors.initials: JQ
authors.lastname: Feng
authors.forename: Chen-Heng
authors.initials: CH
authors.lastname: Hu
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects*; D015687:Cell Hypoxia / Q000187:drug effects; D003035:Cobalt; D019610:Cytoprotection / Q000187:drug effects*; D003603:Cytotoxins; D015536:Down-Regulation / Q000187:drug effects; D004353:Drug Evaluation, Preclinical; D018841:HSP90 Heat-Shock Proteins / Q000378:metabolism / Q000502:physiology*; D006862:Hydrogen Sulfide / Q000494:pharmacology*; D000860:Hypoxia / Q000139:chemically induced / Q000150:complications* / Q000378:metabolism / Q000473:pathology; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D018696:Neuroprotective Agents / Q000494:pharmacology; D016716:PC12 Cells; D051381:Rats; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: D000975:Antioxidants; D003603:Cytotoxins; D018841:HSP90 Heat-Shock Proteins; D018696:Neuroprotective Agents; D017382:Reactive Oxygen Species; D003035:Cobalt; C018021:cobaltous chloride; D006862:Hydrogen Sulfide