17beta-estradiol inhibits oxidative stress-induced apoptosis in keratinocytes by promoting Bcl-2 expression.
We examined in vitro effects of 17beta-estradiol on H2O2-induced apoptosis in human keratinocytes. 17beta-estradiol prevented the H2O2-induced apoptosis. H2O2 decreased, whereas 17beta-estradiol increased Bcl-2 protein and mRNA levels in keratinocytes, and H2O2 plus 17beta-estradiol led to basal levels. Overexpression of Bcl-2 protected keratinocytes against H2O2-induced apoptosis, indicating the anti-apoptotic effect of Bcl-2. H2O2 suppressed, whereas 17beta-estradiol enhanced bcl-2 promoter activity, and H2O2 plus 17beta-estradiol led to basal activity. Cyclic adenosine monophosphate (cAMP) response element on bcl-2 promoter was responsible for the effects of 17beta-estradiol and H2O2. Bcl-2 expression was enhanced by membrane-impermeable bovine serum albumin-conjugated 17beta-estradiol, indicating the effects via membrane 17beta-estradiol-binding sites. H2O2 decreased, whereas 17beta-estradiol increased the amount of phosphorylated cAMP response element-binding protein and cAMP response element-dependent transcriptional activity, and H2O2 plus 17beta-estradiol led to basal levels. H-89, an inhibitor of cAMP-dependent protein kinase A, suppressed basal and 17beta-estradiol-induced cAMP response element-binding protein phosphorylation, cAMP response element-dependent transcriptional activity, Bcl-2 expression, and apoptosis resistance. The cAMP analog, dibutyryl cAMP, enhanced cAMP response element-binding protein phosphorylation, cAMP response element-dependent transcriptional activity, Bcl-2 expression, and apoptosis resistance. 17Beta-estradiol increased intracellular cAMP level and protein kinase A activity, whereas these were not altered by H2O2. Keratinocytes expressed mRNA for estrogen receptor beta and guanine nucleotide-binding protein-coupled receptor, GPR30. GPR30 anti-sense oligonucleotide did, but anti-sense estrogen receptor beta did not suppress 17beta-estradiol-induced cAMP signal, cAMP response element-binding protein phosphorylation, Bcl-2 expression, and apoptosis resistance. These results suggest that 17beta-estradiol may enhance Bcl-2 expression and prevent H2O2-induced apoptosis by phosphorylating cAMP response element-binding protein via cAMP/protein kinase A pathway in keratinocytes. These effects of 17beta-estradiol may be mediated via membrane GPR30.
Kanda
Naoko
N
Teikyo University, Tokyo, Japan. nmk@med.teikyo-u.ac.jp
Watanabe
Shinichi
S
D017209:Apoptosis / Q000187:drug effects*; D000242:Cyclic AMP / Q000378:metabolism; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D016373:DNA, Antisense; D004958:Estradiol / Q000494:pharmacology*; D015870:Gene Expression / Q000187:drug effects / Q000502:physiology; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism; D066298:In Vitro Techniques; D015603:Keratinocytes / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D018384:Oxidative Stress / Q000502:physiology; D010766:Phosphorylation; D011401:Promoter Regions, Genetic / Q000502:physiology; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics*; D012333:RNA, Messenger / Q000378:metabolism; D011960:Receptors, Estrogen; D043562:Receptors, G-Protein-Coupled / Q000235:genetics; D012710:Serum Albumin, Bovine / Q000494:pharmacology; D012867:Skin / Q000166:cytology; D015533:Transcriptional Activation / Q000187:drug effects
D017362:Cyclic AMP Response Element-Binding Protein; D016373:DNA, Antisense; C109584:GPER1 protein, human; D019253:Proto-Oncogene Proteins c-bcl-2; D012333:RNA, Messenger; D011960:Receptors, Estrogen; D043562:Receptors, G-Protein-Coupled; D012710:Serum Albumin, Bovine; D004958:Estradiol; D006861:Hydrogen Peroxide; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases