Rapid nongenomic E2 effects on p42/p44 MAPK, activator protein-1, and cAMP response element binding protein in rat white adipocytes.
In some tissues, rapid effects of estrogens have been described at the plasma membrane level including activation of the MAPK activity. In rat adipocytes, the present study demonstrates that physiological concentrations (0.1-10 nM) of E2 rapidly activate the p42/p44 MAPK. This effect was blocked by the pure estrogen antagonist, ICI 182 780, and appeared specific for E2 because 17alpha-E2, T, and progesterone failed to change the MAPK activity. Pertussis toxin; PP2, a selective inhibitor of Src family kinase; and wortmannin all reduced the magnitude of MAPK activation by E2 suggesting involvement of the Gi-protein/Src family kinase/PI3K pathway. Classical PKCs and MAPK kinase were also involved in MAPK activation by E2. Interestingly, this activation was observed in late but not early differentiated rat preadipocytes, and the immunoreactive ER(alpha) protein was detected only in adipocyte membrane, suggesting that the adipocyte membrane structure is required for the nongenomic effect of E2. Moreover, E2 induced a rapid nuclear translocation of MAPK together with a fast MAPK- dependent activation of cAMP response element binding protein leading to a transcriptional activation of cAMP response element binding protein-responsive genes and reported plasmids. However, the E2 increase in adipocyte activator protein-1 DNA binding does not seem to be fully explained by the E2 activation of the MAPK pathway. This study provides clear evidence for an additional nongenomic mechanism whereby estrogens may exert their control on adipose tissue metabolism.
Dos Santos
Esther Garcia
EG
Faculté de Médecine Paris-Ouest, Université René Descartes and Laboratoire de Biochimie et Biologie Moléculaire, Centre Hospitalier de Poissy, 78303 France.
Dieudonne
Marie Noëlle
MN
Pecquery
René
R
Le Moal
Vincent
V
Giudicelli
Yves
Y
Lacasa
Danièle
D
D017667:Adipocytes / Q000378:metabolism*; D000818:Animals; D015153:Blotting, Western; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism; D002478:Cells, Cultured; D017362:Cyclic AMP Response Element-Binding Protein / Q000096:biosynthesis* / Q000235:genetics; D004586:Electrophoresis; D004789:Enzyme Activation / Q000187:drug effects; D020536:Enzyme Activators / Q000494:pharmacology; D004958:Estradiol / Q000494:pharmacology*; D005786:Gene Expression Regulation / Q000187:drug effects; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D019950:Mitogen-Activated Protein Kinase 1 / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction; D018808:Transcription Factor AP-1 / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D014162:Transfection
D017362:Cyclic AMP Response Element-Binding Protein; D020536:Enzyme Activators; D012333:RNA, Messenger; D018808:Transcription Factor AP-1; D004958:Estradiol; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases