3beta-Hydroxysteroid-delta24 reductase is a hydrogen peroxide scavenger, protecting cells from oxidative stress-induced apoptosis.
3beta-Hydroxysteroid-Delta24 reductase (DHCR24) is an endoplasmic reticulum-resident, multifunctional enzyme that possesses antiapoptotic and cholesterol-synthesizing activities. To clarify the molecular basis of the former activity, we investigated the effects of hydrogen peroxide (H(2)O(2)) on embryonic fibroblasts prepared from DHCR24-knockout mice (DHCR24(-/-) mouse embryonic fibroblasts). H(2)O(2) exposure rapidly induced apoptosis, which was associated with sustained activation of apoptosis signal-regulating kinase-1 and stress-activated protein kinases, such as p38 MAPK and c-Jun N-terminal kinase. Complementation of the mouse embryonic fibroblasts by adenovirus expressing DHCR24 attenuated the H(2)O(2)-induced kinase activation and apoptosis. Concomitantly, intracellular generation of reactive oxygen species (ROS) in response to H(2)O(2) was also diminished by the adenovirus, suggesting a ROS-scavenging activity of DHCR24. Such antiapoptotic effects of DHCR24 were duplicated in pheochromocytoma PC12 cells infected with adenovirus. In addition, it was found that DHCR24 exerted cytoprotective effects in the tunicamycin-induced endoplasmic reticulum stress by eliminating ROS. Finally, using in vitro-synthesized and purified proteins, DHCR24 and its C-terminal deletion mutant were found to exhibit high H(2)O(2)-scavenging activity, whereas the N-terminal deletion mutant lost such activity. These results demonstrate that DHCR24 can directly scavenge H(2)O(2), thereby protecting cells from oxidative stress-induced apoptosis.
Lu
Xiuli
X
Department of Endocrinology, Research Institute of Environmental Medicine, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Japan.
Kambe
Fukushi
F
Cao
Xia
X
Kozaki
Yasuko
Y
Kaji
Takahide
T
Ishii
Takehisa
T
Seo
Hisao
H
D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D015153:Blotting, Western; D002460:Cell Line; D006861:Hydrogen Peroxide / Q000378:metabolism* / Q000494:pharmacology; D007150:Immunohistochemistry; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism; D048848:MAP Kinase Kinase Kinase 5 / Q000378:metabolism; D051379:Mice; D018345:Mice, Knockout; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D018384:Oxidative Stress / Q000502:physiology*; D044925:Oxidoreductases Acting on CH-CH Group Donors / Q000235:genetics / Q000378:metabolism*; D016716:PC12 Cells; D051381:Rats; D017382:Reactive Oxygen Species / Q000378:metabolism; D014162:Transfection; D014415:Tunicamycin / Q000494:pharmacology; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
D009419:Nerve Tissue Proteins; D017382:Reactive Oxygen Species; D014415:Tunicamycin; D006861:Hydrogen Peroxide; D044925:Oxidoreductases Acting on CH-CH Group Donors; C437069:3beta-hydroxysterol delta24-reductase; D048031:JNK Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D048848:MAP Kinase Kinase Kinase 5