title: Estrogen activates phosphatases and antagonizes growth-promoting effect of angiotensin II.
abstract: Accumulating evidence suggests that estrogen exerts cardioprotective effects and protects against neointima formation in response to vascular injury in vivo, whereas angiotensin (Ang) II stimulation via the Ang II type 1 (AT(1)) receptor exaggerates vascular injury. We postulate that estrogen treatment antagonizes the AT(1) receptor-mediated growth-promoting effects in vascular smooth muscle cells (VSMCs). The present in vitro study was designed to explore this possibility and to establish the cellular mechanism whereby estrogen attenuates the growth of VSMCs. Primary cultures of VSMCs derived from male adult Sprague-Dawley rats express exclusively AT(1) receptors. Treatment with Ang II enhanced proliferation of VSMC and c-fos expression, whereas 17beta-estradiol (E2) attenuated these vasotrophic effects of Ang II. We also demonstrated that E2 attenuated AT(1) receptor-mediated extracellular signal-regulated kinase activation and that this effect of E2 was restored by pretreatment with vanadate or okadaic acid. Moreover, we demonstrated that E2 enhanced SHP-1 activity, rapidly reaching a peak after 3 minutes of E2 stimulation, whereas E2 transactivated mitogen-activated protein kinase phosphatase-1 expression, showing a peak after 60 minutes of E2 treatment. SHP-1 activation was not influenced by actinomycin D treatment, whereas E2-mediated mitogen-activated protein kinase phosphatase-1 expression was attenuated. Taken together, our results suggest a novel mechanism of vasoprotection by which estrogen antagonizes the effect of the AT(1) receptor via the activation and induction of phosphatases through nongenomic as well as genomic signaling.
authors.affiliation: Department of Medical Biochemistry Ehime University School of Medicine, Ehime, Japan.
authors.forename: Yuko
authors.initials: Y
authors.lastname: Takeda-Matsubara
authors.forename: Hironori
authors.initials: H
authors.lastname: Nakagami
authors.forename: Masaru
authors.initials: M
authors.lastname: Iwai
authors.forename: Tai-Xing
authors.initials: TX
authors.lastname: Cui
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Shiuchi
authors.forename: Masahiro
authors.initials: M
authors.lastname: Akishita
authors.forename: Clara
authors.initials: C
authors.lastname: Nahmias
authors.forename: Masaharu
authors.initials: M
authors.lastname: Ito
authors.forename: Masatsugu
authors.initials: M
authors.lastname: Horiuchi
mesh_terms: D000804:Angiotensin II / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D057911:Angiotensin Receptor Antagonists; D000818:Animals; D018797:Cell Cycle Proteins; D002455:Cell Division / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D004347:Drug Interactions; D054638:Dual Specificity Phosphatase 1; D004789:Enzyme Activation / Q000187:drug effects; D004958:Estradiol / Q000494:pharmacology*; D017874:Immediate-Early Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins; D020935:MAP Kinase Signaling System / Q000187:drug effects / Q000502:physiology; D008297:Male; D020929:Mitogen-Activated Protein Kinase Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects / Q000201:enzymology; D010749:Phosphoprotein Phosphatases; D054645:Protein Phosphatase 1; D054562:Protein Tyrosine Phosphatase, Non-Receptor Type 1; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; D017027:Protein Tyrosine Phosphatases / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D020239:Receptor Cross-Talk / Q000187:drug effects / Q000502:physiology; D044140:Receptor, Angiotensin, Type 1; D011945:Receptors, Angiotensin / Q000502:physiology; D011960:Receptors, Estrogen / Q000502:physiology
chemical_list: D057911:Angiotensin Receptor Antagonists; D018797:Cell Cycle Proteins; D017874:Immediate-Early Proteins; D047908:Intracellular Signaling Peptides and Proteins; D044140:Receptor, Angiotensin, Type 1; D011945:Receptors, Angiotensin; D011960:Receptors, Estrogen; D000804:Angiotensin II; D004958:Estradiol; D020929:Mitogen-Activated Protein Kinase Kinases; D010749:Phosphoprotein Phosphatases; D054645:Protein Phosphatase 1; D054638:Dual Specificity Phosphatase 1; C517021:Dusp1 protein, rat; D054562:Protein Tyrosine Phosphatase, Non-Receptor Type 1; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; D017027:Protein Tyrosine Phosphatases; C516727:Ptpn11 protein, rat; C509250:Ptpn6 protein, rat