title: Expression and functional roles of estrogen receptor GPR30 in human intervertebral disc.
abstract: Estrogen withdrawal, a characteristic of female aging, is associated with age-related intervertebral disc (IVD) degeneration. The function of estrogen is mediated by two classic nuclear receptors, estrogen receptor (ER)-α and -β, and a membrane bound G-protein-coupled receptor 30 (GPR30). To date, the expression and function of GPR30 in human spine is poorly understood. This study aimed to evaluate GPR30 expression in IVD, and its role in estrogen-related regulation of proliferation and apoptosis of disc nucleus pulposus (NP) cells. GPR30 expression was examined in 30 human adult NP and 9 fetal IVD. Results showed that GPR30 was expressed in NP cells at both mRNA and protein levels. In human fetal IVD, GPR30 protein was expressed in the NP at 12-14 weeks gestation, but was undetectable at 8-11 weeks. The effect of 17β-estradiol (E2) on GPR30-mediated proliferation and interleukin-1β (IL-1β)-induced apoptosis of NP cells was investigated. Cultured NP cells were treated with or without E2, GPR30 antagonist G36, and ER antagonist ICI 182,780. NP cell viability was tested by MTS assay. Apoptosis was determined by flow cytometry using fluorescence labeled annexin-V, TUNEL assay and immumnocytochemical staining of activated caspase-3. E2 enhanced cell proliferation and prevented IL-1β-induced cell death, but the effect was partially blocked by G36 and completely abrogated by a combination of ICI 182,780 and G36. This study demonstrates that GPR30 is expressed in human IVD to transmit signals triggering E2-induced NP cell proliferation and protecting against IL-1β-induced apoptosis. The effects of E2 on NP cells require both GPR30 and classic estrogen receptors.
authors.affiliation: Department of Orthopedic Research, Orthopedic Research Institute, St George Hospital, University of New South Wales, Sydney, Australia.
authors.forename: Aiqun
authors.initials: A
authors.lastname: Wei
authors.affiliation: Department of Orthopedic Research, Orthopedic Research Institute, St George Hospital, University of New South Wales, Sydney, Australia.
authors.forename: Bojiang
authors.initials: B
authors.lastname: Shen
authors.affiliation: Department of Orthopedic Research, Orthopedic Research Institute, St George Hospital, University of New South Wales, Sydney, Australia.
authors.forename: Lisa A
authors.initials: LA
authors.lastname: Williams
authors.affiliation: Department of Orthopedic Research, Orthopedic Research Institute, St George Hospital, University of New South Wales, Sydney, Australia.
authors.forename: Divya
authors.initials: D
authors.lastname: Bhargav
authors.affiliation: Department of Hematology, St George Hospital, University of New South Wales, Sydney, Australia.
authors.forename: Feng
authors.initials: F
authors.lastname: Yan
authors.affiliation: Department of Hematology, St George Hospital, University of New South Wales, Sydney, Australia.
authors.forename: Beng H
authors.initials: BH
authors.lastname: Chong
authors.affiliation: Department of Orthopedic Research, Orthopedic Research Institute, St George Hospital, University of New South Wales, Sydney, Australia. Electronic address: a.diwan@spine-service.org.
authors.forename: Ashish D
authors.initials: AD
authors.lastname: Diwan
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D017209:Apoptosis / Q000187:drug effects; D052117:Benzodioxoles / Q000494:pharmacology; D002478:Cells, Cultured; D004958:Estradiol / Q000031:analogs & derivatives / Q000494:pharmacology; D065171:Estrogen Receptor Antagonists / Q000494:pharmacology; D004967:Estrogens / Q000494:pharmacology; D005260:Female; D005333:Fetus / Q000378:metabolism; D000077267:Fulvestrant; D006801:Humans; D053583:Interleukin-1beta / Q000494:pharmacology; D007403:Intervertebral Disc / Q000166:cytology / Q000378:metabolism*; D055959:Intervertebral Disc Degeneration / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D011804:Quinolines / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D011960:Receptors, Estrogen / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D043562:Receptors, G-Protein-Coupled / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D055815:Young Adult
chemical_list: D052117:Benzodioxoles; D065171:Estrogen Receptor Antagonists; D004967:Estrogens; C000603178:G36 compound; C109584:GPER1 protein, human; D053583:Interleukin-1beta; D011804:Quinolines; D012333:RNA, Messenger; D011960:Receptors, Estrogen; D043562:Receptors, G-Protein-Coupled; D000077267:Fulvestrant; D004958:Estradiol
keywords: Estrogen receptor; GPER; GPR30; Intervertebral disc; Nucleus pulposus