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Casarini L, Santi D, Brigante G, Simoni M. Two Hormones for One Receptor: Evolution, Biochemistry, Actions, and Pathophysiology of LH and hCG. Endocr Rev 2018; 39:549-592. [PMID: 29905829 DOI: 10.1210/er.2018-00065] [Citation(s) in RCA: 94] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Accepted: 06/08/2018] [Indexed: 01/03/2023]
Abstract
LH and chorionic gonadotropin (CG) are glycoproteins fundamental to sexual development and reproduction. Because they act on the same receptor (LHCGR), the general consensus has been that LH and human CG (hCG) are equivalent. However, separate evolution of LHβ and hCGβ subunits occurred in primates, resulting in two molecules sharing ~85% identity and regulating different physiological events. Pituitary, pulsatile LH production results in an ~90-minute half-life molecule targeting the gonads to regulate gametogenesis and androgen synthesis. Trophoblast hCG, the "pregnancy hormone," exists in several isoforms and glycosylation variants with long half-lives (hours) and angiogenic potential and acts on luteinized ovarian cells as progestational. The different molecular features of LH and hCG lead to hormone-specific LHCGR binding and intracellular signaling cascades. In ovarian cells, LH action is preferentially exerted through kinases, phosphorylated extracellular-regulated kinase 1/2 (pERK1/2) and phosphorylated AKT (also known as protein kinase B), resulting in irreplaceable proliferative/antiapoptotic signals and partial agonism on progesterone production in vitro. In contrast, hCG displays notable cAMP/protein kinase A (PKA)-mediated steroidogenic and proapoptotic potential, which is masked by estrogen action in vivo. In vitro data have been confirmed by a large data set from assisted reproduction, because the steroidogenic potential of hCG positively affects the number of retrieved oocytes, and LH affects the pregnancy rate (per oocyte number). Leydig cell in vitro exposure to hCG results in qualitatively similar cAMP/PKA and pERK1/2 activation compared with LH and testosterone. The supposed equivalence of LH and hCG has been disproved by such data, highlighting their sex-specific functions and thus deeming it an oversight caused by incomplete understanding of clinical data.
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Affiliation(s)
- Livio Casarini
- Department of Biomedical, Metabolic, and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy.,Center for Genomic Research, University of Modena and Reggio Emilia, Modena, Italy
| | - Daniele Santi
- Department of Biomedical, Metabolic, and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy.,Unit of Endocrinology, Department of Medical Specialties, Azienda Ospedaliero-Universitaria, Modena, Italy
| | - Giulia Brigante
- Department of Biomedical, Metabolic, and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy.,Unit of Endocrinology, Department of Medical Specialties, Azienda Ospedaliero-Universitaria, Modena, Italy
| | - Manuela Simoni
- Department of Biomedical, Metabolic, and Neural Sciences, University of Modena and Reggio Emilia, Modena, Italy.,Center for Genomic Research, University of Modena and Reggio Emilia, Modena, Italy.,Unit of Endocrinology, Department of Medical Specialties, Azienda Ospedaliero-Universitaria, Modena, Italy
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Chung CK, Ge W. Human chorionic gonadotropin (hCG) induces MAPK3/1 phosphorylation in the zebrafish ovarian follicle cells independent of EGF/EGFR pathway. Gen Comp Endocrinol 2013; 188:251-7. [PMID: 23644153 DOI: 10.1016/j.ygcen.2013.04.020] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2013] [Accepted: 04/15/2013] [Indexed: 01/08/2023]
Abstract
In mammals, human chorionic gonadotropin (hCG), a luteinizing hormone (LH) analogue, induces MAPK3/1 phosphorylation in the granulosa cells and this event is largely dependent on epidermal growth factor receptor (EGFR) activity. However, whether this mechanism also works in other vertebrates such as fish remains unknown. Here, we showed that treatment of cultured zebrafish ovarian follicle cells with hCG also resulted in MAPK3/1 phosphorylation without affecting the total protein level of MAPK3/1. The phosphorylation level peaked at 5 min and then declined to the basal level after 40 min of hCG treatment. Further experiment showed that H89 (a PKA inhibitor) could abolish hCG-stimulated MAPK3/1 phosphorylation, but had no effect on EGF-induced phosphorylation, suggesting a mediating role for cAMP/PKA in hCG activation of MAPK3/1. On the other hand, AG1478 (an EGFR inhibitor) completely blocked EGF-stimulated MAPK3/1 phosphorylation, but had no effect on the hCG-induced MAPK3/1 phosphorylation. These data indicate that similar to its action in mammals, hCG/LH also stimulated MAPK3/1 phosphorylation in the zebrafish ovarian follicle cells; however, unlike the situation in the mammalian ovary, the hCG-stimulated MAPK3/1 phosphorylation in cultured zebrafish ovarian follicle cells was independent of EGFR.
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Affiliation(s)
- Chi-Kin Chung
- School of Life Sciences and Centre for Cell and Developmental Biology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
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Light A, Hammes SR. Membrane receptor cross talk in steroidogenesis: recent insights and clinical implications. Steroids 2013; 78:633-8. [PMID: 23380369 DOI: 10.1016/j.steroids.2012.12.016] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2012] [Revised: 12/17/2012] [Accepted: 12/31/2012] [Indexed: 11/19/2022]
Abstract
Steroid production by all three major steroidogenic tissues, the adrenals, testes, and ovaries, is critical for survival and reproduction of all animals. As such, the pathways that regulate steroidogenesis are conserved between these tissues, from the steroidogenic enzymes and cofactors that synthesize steroids, to the intracellular signaling molecules and Gαs-coupled receptors that mediate the activity of these enzymes. Recent work has revealed another important conserved pathway in steroidogenesis: crosstalk between membrane G protein-coupled receptors and membrane receptor tyrosine kinases. Luteinizing hormone (LH) or adrencorticotropic hormone (ACTH) binding to their cognate Gαs-coupled membrane receptors in the gonads and adrenals, respectively, leads to cAMP-induced trans-activation of the epidermal growth factor (EGF) receptor, followed by activation of Akt and Erk signaling. These kinase signals then activate Steroidogenic Acute Regulatory (StAR) protein, which promotes steroid production. Inhibition of this pathway abrogates both LH- and ACTH-induced steroidogenesis. Interestingly, LH-induced transactivation of the EGF receptor in the ovary uniquely requires matrix metalloproteinase-mediated release of EGF receptor ligands, and inhibition of these proteases blocks LH-induced steroidogenesis. Given this unique need for matrix metalloproteinases in ovarian steroidogenesis, MMP inhibition may prove to be useful when treating diseases of excess ovarian steroid production, such as polycystic ovary syndrome.
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Affiliation(s)
- Allison Light
- Division of Endocrinology and Metabolism, Department of Medicine, University of Rochester School of Medicine, 601 Elmwood Ave., Rochester, NY 14642, USA
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Di Giorgio NP, Catalano PN, López PV, González B, Semaan SJ, López GC, Kauffman AS, Rulli SB, Somoza GM, Bettler B, Libertun C, Lux-Lantos VA. Lack of functional GABAB receptors alters Kiss1 , Gnrh1 and Gad1 mRNA expression in the medial basal hypothalamus at postnatal day 4. Neuroendocrinology 2013; 98:212-23. [PMID: 24080944 PMCID: PMC3915412 DOI: 10.1159/000355631] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2013] [Accepted: 09/10/2013] [Indexed: 01/01/2023]
Abstract
BACKGROUND/AIMS Adult mice lacking functional GABAB receptors (GABAB1KO) show altered Gnrh1 and Gad1 expressions in the preoptic area-anterior hypothalamus (POA-AH) and females display disruption of cyclicity and fertility. Here we addressed whether sexual differentiation of the brain and the proper wiring of the GnRH and kisspeptin systems were already disturbed in postnatal day 4 (PND4) GABAB1KO mice. METHODS PND4 wild-type (WT) and GABAB1KO mice of both sexes were sacrificed; tissues were collected to determine mRNA expression (qPCR), amino acids (HPLC), and hormones (RIA and/or IHC). RESULTS GnRH neuron number (IHC) did not differ among groups in olfactory bulbs or OVLT-POA. Gnrh1 mRNA (qPCR) in POA-AH was similar among groups. Gnrh1 mRNA in medial basal hypothalamus (MBH) was similar in WTs but was increased in GABAB1KO females compared to GABAB1KO males. Hypothalamic GnRH (RIA) was sexually different in WTs (males > females), but this sex difference was lost in GABAB1KOs; the same pattern was observed when analyzing only the MBH, but not in the POA-AH. Arcuate nucleus Kiss1 mRNA (micropunch-qPCR) was higher in WT females than in WT males and GABAB1KO females. Gad1 mRNA in MBH was increased in GABAB1KO females compared to GABAB1KO males. Serum LH and gonadal estradiol content were also increased in GABAB1KOs. CONCLUSION We demonstrate that GABABRs participate in the sexual differentiation of the ARC/MBH, because sex differences in several reproductive genes, such as Gad1, Kiss1 and Gnrh1, are critically disturbed in GABAB1KO mice at PND4, probably altering the organization and development of neural circuits governing the reproductive axis.
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MESH Headings
- Animals
- Animals, Newborn
- Arcuate Nucleus of Hypothalamus/growth & development
- Arcuate Nucleus of Hypothalamus/metabolism
- Female
- Gene Expression Regulation, Developmental
- Glutamate Decarboxylase/deficiency
- Glutamate Decarboxylase/genetics
- Gonadotropin-Releasing Hormone/deficiency
- Gonadotropin-Releasing Hormone/genetics
- Hypothalamus, Middle/growth & development
- Hypothalamus, Middle/metabolism
- Kisspeptins/deficiency
- Kisspeptins/genetics
- Male
- Mice
- Mice, Inbred BALB C
- Mice, Knockout
- Protein Precursors/deficiency
- Protein Precursors/genetics
- RNA, Messenger/biosynthesis
- RNA, Messenger/genetics
- Receptors, GABA-B/deficiency
- Receptors, GABA-B/genetics
- Sex Differentiation/genetics
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Affiliation(s)
- Noelia P Di Giorgio
- Laboratorio de Neuroendocrinología, Instituto de Biología y Medicina Experimental (IBYME-CONICET), Buenos Aires, Argentina
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Conti M, Hsieh M, Zamah AM, Oh JS. Novel signaling mechanisms in the ovary during oocyte maturation and ovulation. Mol Cell Endocrinol 2012; 356:65-73. [PMID: 22101318 PMCID: PMC4104635 DOI: 10.1016/j.mce.2011.11.002] [Citation(s) in RCA: 256] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/19/2011] [Revised: 11/04/2011] [Accepted: 11/04/2011] [Indexed: 10/15/2022]
Abstract
During the peri-ovulatory period, the gonadotropin LH triggers major changes in both the somatic and germ cell compartments of the ovarian follicle. The oocyte completes the meiotic cell cycle to become a fertilizable egg, and dramatic changes in gene expression and secretion take place in the somatic compartment of the follicle in preparation for follicular rupture and oocyte release. The concerted changes are regulated by activation of intracellular signaling pathways as well as paracrine and autocrine regulatory loops. This review will provide a summary of the current knowledge of the molecular events triggered by LH focusing mostly on the signaling pathways required for oocyte maturation.
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Affiliation(s)
- Marco Conti
- Center for Reproductive Sciences, Department of Obstetrics and Gynecology and Reproductive Sciences, University of California San Francisco, San Francisco, CA 94143, United States.
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Abstract
The lutropin receptor (LHR) is a G protein-coupled receptor (GPCR) that mediates the actions of pituitary LH in males and females and that of placental hCG in pregnant women and, therefore, plays an essential role in reproductive physiology. Mutations of the lhcgr gene that result in constitutive activation of the LHR have been shown to be causative of gonadotropin-independent precocious puberty in young boys. Studies on constitutively active mutants (CAMs) of the LHR have been extremely informative in elucidating the roles of the LHR in reproductive physiology as well as in understanding the molecular basis underlying activation of this GPCR. The constitutive activities of hLHR CAMs can be attenuated by introducing mutations into the CAMs that stabilize the resting state of the hLHR or by coexpressing the hLHR CAMs with an hLHR mutant that is stabilized in the resting state, allowing the two forms of the hLHR to heterodimerize. This chapter describes the experimental methods and strategies underlying studies of hLHR CAMs.
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Andric N, Thomas M, Ascoli M. Transactivation of the epidermal growth factor receptor is involved in the lutropin receptor-mediated down-regulation of ovarian aromatase expression in vivo. Mol Endocrinol 2010; 24:552-60. [PMID: 20093417 DOI: 10.1210/me.2009-0450] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Ovarian follicular development and differentiation is characterized by dramatic changes in aromatase (Cyp19a1) expression. In preovulatory follicles, activation of the FSH receptor increases aromatase expression until the surge of LH decreases it. Here we provide in vivo evidence that down-regulation of Cyp19a1 by the LH surge requires efficient signaling through the epidermal growth factor receptor (EGFR). The human chorionic gonadotropin (hCG)-induced down-regulation of Cyp19a1 expression in the two different mouse models with inactivating mutations of the EGFR (wa2 and velvet) is impaired but not abolished. The hCG-induced phosphorylation of ovarian ERK1/2, expression of C/EBPbeta, and the phosphorylation of Connexin43 (two downstream targets of ERK1/2 action) are also decreased in these two mouse models. In contrast, disruption of EGFR signaling does not have any affect on the hCG-induced phosphorylation of cAMP response element-binding protein or AKT. This study provides the first in vivo evidence linking the LH receptor, the EGFR, and ERK1/2 as sequential components of a pathway that regulates ovarian Cyp19a1 expression.
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Affiliation(s)
- Nebojsa Andric
- Department of Pharmacology, 2-319B BSB, 51 Newton Road, The University of Iowa, Iowa City, Iowa 52242, USA
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Tai P, Shiraishi K, Ascoli M. Activation of the lutropin/choriogonadotropin receptor inhibits apoptosis of immature Leydig cells in primary culture. Endocrinology 2009; 150:3766-73. [PMID: 19406941 PMCID: PMC2717876 DOI: 10.1210/en.2009-0207] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
We used proliferating primary cultures of immature rat Leydig cells expressing the recombinant human LH/choriogonadotropin (CG) receptor (LHR) to test the hypothesis that activation of this receptor inhibits apoptosis. We also compared the effects of LH/CG with epidermal growth factor (EGF) and IGF-I because these have been previously shown to stimulate proliferation and/or inhibit apoptosis in Leydig cells. Human CG (hCG), EGF, and IGF-I stimulated the phosphorylation of ERK1/2 and Akt in primary cultures of immature rat Leydig cells. These three hormones also robustly stimulated thymidine incorporation and inhibited drug-induced apoptosis. Using selective inhibitors of ERK1/2 (UO126) or Akt phosphorylation (LY294002), we show that the ERK1/2 and Akt cascades are both involved in the hCG- and EGF-dependent proliferation of Leydig cells, but only the ERK1/2 cascade is involved in their antiapoptotic actions. The same strategy showed that the proliferative and antiapoptotic actions of IGF-I are mediated entirely by the Akt pathway. These results show that activation of the LHR inhibits apoptosis in Leydig cells and that it does so through stimulation of the ERK1/2 pathway.
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Affiliation(s)
- Ping Tai
- Department of Pharmacology, Carver College of Medicine, The University of Iowa, Iowa City, Iowa 52242, USA
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Segaloff DL. Chapter 4 Diseases Associated with Mutations of the Human Lutropin Receptor. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2009; 89:97-114. [DOI: 10.1016/s1877-1173(09)89004-2] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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Andric N, Ascoli M. The luteinizing hormone receptor-activated extracellularly regulated kinase-1/2 cascade stimulates epiregulin release from granulosa cells. Endocrinology 2008; 149:5549-56. [PMID: 18653716 PMCID: PMC2584583 DOI: 10.1210/en.2008-0618] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
We examine the pathways involved in the luteinizing hormone receptor (LHR)-dependent activation of the epidermal growth factor (EGF) network using cocultures of LHR-positive granulosa cells and LHR-negative test cells expressing an EGF receptor (EGFR)-green fluorescent protein fusion protein. Activation of the LHR in granulosa cells results in the release of EGF-like growth factors that are detected by measuring the phosphorylation of the EGFR-green fluorescent protein expressed only in the LHR-negative test cells. Using neutralizing antibodies and real-time PCR, we identified epiregulin as the main EGF-like growth factor produced upon activation of the LHR expressed in immature rat granulosa cells, and we show that exclusive inhibition or activation of the ERK1/2 cascade in granulosa cells prevents or enhances epiregulin release, respectively, with little or no effect on epiregulin expression. These results show that the LHR-stimulated ERK1/2 pathway stimulates epiregulin release.
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Affiliation(s)
- Nebojsa Andric
- Department of Pharmacology, Carver College of Medicine, The University of Iowa, Iowa City, Iowa 52242, USA
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Galet C, Ascoli M. Arrestin-3 is essential for the activation of Fyn by the luteinizing hormone receptor (LHR) in MA-10 cells. Cell Signal 2008; 20:1822-9. [PMID: 18647647 PMCID: PMC2610675 DOI: 10.1016/j.cellsig.2008.06.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2008] [Revised: 06/10/2008] [Accepted: 06/13/2008] [Indexed: 11/17/2022]
Abstract
Recent studies showed that Fyn is a mediator of the LHR-induced activation of the ERK1/2 cascade in MA-10 cells. Since the LHR is a G protein-coupled receptor and the Src family of kinases can be activated by some Galpha subunits and by the non-visual arrestins we investigated the role of these signaling molecules in the LHR-provoked activation of Fyn. Small interfering RNAs (siRNAs) that target two Galpha subunits that participate in LHR signaling (Galpha(s) and Galpha(11)) and one that targets arrestin-3 were co-transfected with the hLHR in MA-10 cells. We then determined the effects of these siRNAs on the LHR-provoked activation of Fyn, the phosphorylation of FAK (a prominent Fyn substrate) and the release of EGF-like growth factors (a Fyn-mediated process). Expression of the siRNA against Galpha(s) decreased the level of Galpha(s) and LHR-stimulated cAMP production by approximately 50% but did not affect LHR-stimulated Fyn activation or FAK phosphorylation. Likewise, expression of the siRNA against Galpha(11) decreased the level of Galpha(11) and LHR-stimulated inositol phosphate production by approximately 50% but did not affect LHR-stimulated Fyn activation or FAK phosphorylation. Expression of the siRNA against arrestin-3 decreased the level of arrestin-3 and the rate of internalization of hCG by approximately 50% and it also inhibited the LHR-provoked stimulation of Fyn, the phosphorylation of FAK and the release of EGF-like growth factors. These results show that, in MA-10 cells, the hLHR activates Fyn through an arrestin-3-dependent pathway and that this pathway is a mediator of the hLHR-provoked release of EGF-like growth factors.
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Affiliation(s)
- Colette Galet
- Department of Pharmacology, Carver College of Medicine, The University of Iowa, Iowa City, IA 52242, USA
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