TY - JOUR
T1 - Ethanol withdrawal provokes opening of the mitochondrial membrane permeability transition pore in an estrogen-preventable manner
AU - Jung, Marianna E.
AU - Wilson, Andrew M.
AU - Ju, Xiaohua
AU - Wen, Yi
AU - Metzger, Daniel B.
AU - Simpkins, James W.
PY - 2009/3
Y1 - 2009/3
N2 - We have reported that the major endogenous estrogen, 17β-estradiol (E2), protects against oxidative injury during ethanol withdrawal (EW) in a cultured hippocampal cell line (HT22). Here, we investigated whether the pro-oxidant nature of EW mediates opening of the mitochondrial membrane permeability transition pore (PTP) in a manner protected by E2. Excess PTP opening provokes mitochondrial membrane swelling (MMS) and the collapse of membrane potential (Aψm). HT22 cells were collected at the end of ethanol exposure (100 mM) for 24 h or at 4 h of EW to assess MMS by monitoring absorbance decline at 540 nm and to assess Δψm using flow cytometry. Protective effects of E2 on PTP were compared with an antioxidant butylated hydroxytoluene (BHT) and an E2 analog, ZYC26 [(3-hydroxy-2-adamantyl(1)-4- methyl-estra-1,3,5(10)-17-one], with higher antioxidant potency than E2. To assess cellular consequences of PTP opening, effects of a PTP inhibitor (cyclosporin A) on EW-induced cell death were assessed using the calcein assay. Major findings were that: 1) EW resulted in rapid MMS and ΔψPm collapse; 2) cyclosporin A attenuated EW-induced cell death; and 3) E2 treatment restricted to the EW phase protected against the PTP opening more prominently than BHT and to a similar degree to ZYC26. These findings suggest that EW provokes PTP opening partly but not entirely through the pro-oxidant nature and that E2 counteracts EW-associated factors to protect against the PTP opening.
AB - We have reported that the major endogenous estrogen, 17β-estradiol (E2), protects against oxidative injury during ethanol withdrawal (EW) in a cultured hippocampal cell line (HT22). Here, we investigated whether the pro-oxidant nature of EW mediates opening of the mitochondrial membrane permeability transition pore (PTP) in a manner protected by E2. Excess PTP opening provokes mitochondrial membrane swelling (MMS) and the collapse of membrane potential (Aψm). HT22 cells were collected at the end of ethanol exposure (100 mM) for 24 h or at 4 h of EW to assess MMS by monitoring absorbance decline at 540 nm and to assess Δψm using flow cytometry. Protective effects of E2 on PTP were compared with an antioxidant butylated hydroxytoluene (BHT) and an E2 analog, ZYC26 [(3-hydroxy-2-adamantyl(1)-4- methyl-estra-1,3,5(10)-17-one], with higher antioxidant potency than E2. To assess cellular consequences of PTP opening, effects of a PTP inhibitor (cyclosporin A) on EW-induced cell death were assessed using the calcein assay. Major findings were that: 1) EW resulted in rapid MMS and ΔψPm collapse; 2) cyclosporin A attenuated EW-induced cell death; and 3) E2 treatment restricted to the EW phase protected against the PTP opening more prominently than BHT and to a similar degree to ZYC26. These findings suggest that EW provokes PTP opening partly but not entirely through the pro-oxidant nature and that E2 counteracts EW-associated factors to protect against the PTP opening.
UR - http://www.scopus.com/inward/record.url?scp=62449307995&partnerID=8YFLogxK
U2 - 10.1124/jpet.108.146829
DO - 10.1124/jpet.108.146829
M3 - Article
C2 - 19050172
AN - SCOPUS:62449307995
SN - 0022-3565
VL - 328
SP - 692
EP - 698
JO - Journal of Pharmacology and Experimental Therapeutics
JF - Journal of Pharmacology and Experimental Therapeutics
IS - 3
ER -