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Stojilkovic SS, Previde RM, Sherman AS, Fletcher PA. Pituitary corticotroph identity and receptor-mediated signaling: A transcriptomics perspective. CURRENT OPINION IN ENDOCRINE AND METABOLIC RESEARCH 2022; 25. [PMID: 36177190 PMCID: PMC9514143 DOI: 10.1016/j.coemr.2022.100364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Recent single-cell RNA sequencing has offered an unprecedented view of pituitary cell transcriptomic profiles. In this review, these new data are briefly discussed and compared with the classical literature, focusing on pituitary corticotrophs. These cells are introduced by discussing their marker genes, followed by a review of G protein-coupled receptor gene expression, heterotrimeric G protein genes, and genes encoding signaling pathways downstream of G proteins: adenylate cyclases, phosphodiesterases, phospholipases, and protein kinases. The expression patterns of enzyme-linked plasma membrane and nuclear hormone receptor genes was also analyzed. The overview of these selected groups of genes sheds new light on corticotrophic receptors and their signaling pathways and provides guidance for further basic and clinical research by identifying genes that not been studied so far.
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Affiliation(s)
- Stanko S. Stojilkovic
- Section on Cellular Signaling, The Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
- Correspondence: Stanko S. Stojilkovic ()
| | - Rafael M. Previde
- Section on Cellular Signaling, The Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Arthur S. Sherman
- Laboratory of Biological Modeling, National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health (NIH), Bethesda, MD 20892, USA
| | - Patrick A. Fletcher
- Laboratory of Biological Modeling, National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health (NIH), Bethesda, MD 20892, USA
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Hertz L, Chen Y. Importance of astrocytes for potassium ion (K+) homeostasis in brain and glial effects of K+ and its transporters on learning. Neurosci Biobehav Rev 2016; 71:484-505. [DOI: 10.1016/j.neubiorev.2016.09.018] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 08/12/2016] [Accepted: 09/23/2016] [Indexed: 10/20/2022]
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Bliss SP, Navratil AM, Xie J, Roberson MS. GnRH signaling, the gonadotrope and endocrine control of fertility. Front Neuroendocrinol 2010; 31:322-40. [PMID: 20451543 PMCID: PMC2923852 DOI: 10.1016/j.yfrne.2010.04.002] [Citation(s) in RCA: 151] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/02/2010] [Revised: 04/26/2010] [Accepted: 04/30/2010] [Indexed: 11/28/2022]
Abstract
Mammalian reproductive cycles are controlled by an intricate interplay between the hypothalamus, pituitary and gonads. Central to the function of this axis is the ability of the pituitary gonadotrope to appropriately respond to stimulation by gonadotropin-releasing hormone (GnRH). This review focuses on the role of cell signaling and in particular, mitogen-activated protein kinase (MAPK) activities regulated by GnRH that are necessary for normal fertility. Recently, new mouse models making use of conditional gene deletion have shed new light on the relationships between GnRH signaling and fertility in both male and female mice. Within the reproductive axis, GnRH signaling is initiated through discrete membrane compartments in which the receptor resides leading to the activation of the extracellular signal-regulated kinases (ERKs 1/2). As defined by gonadotrope-derived cellular models, the ERKs appear to play a central role in the regulation of a cohort of immediate early genes that regulate the expression of late genes that, in part, define the differentiated character of the gonadotrope. Recent data would suggest that in vivo, conditional, pituitary-specific disruption of ERK signaling by GnRH leads to a gender-specific perturbation of fertility. Double ERK knockout in the anterior pituitary leads to female infertility due to LH biosynthesis deficiency and a failure in ovulation. In contrast, male mice are modestly LH deficient; however, this does not have an appreciable impact on fertility.
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Affiliation(s)
- Stuart P Bliss
- Department of Biomedical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, United States
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4
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Specific subcellular targeting of PKCα and PKCε in normal and tumoral lactotroph cells by PMA-mitogenic stimulus. J Mol Histol 2010; 40:417-25. [DOI: 10.1007/s10735-010-9255-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2009] [Accepted: 02/09/2010] [Indexed: 10/19/2022]
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Dewing P, Christensen A, Bondar G, Micevych P. Protein kinase C signaling in the hypothalamic arcuate nucleus regulates sexual receptivity in female rats. Endocrinology 2008; 149:5934-42. [PMID: 18653714 PMCID: PMC2613064 DOI: 10.1210/en.2008-0847] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Rapid membrane-mediated estradiol signaling regulating sexual receptivity requires the interaction of the estrogen receptor (ER)-alpha and the metabotropic glutamate receptor 1a (mGluR1a). A cell signaling antibody microarray revealed that estradiol activated 42 proteins in the arcuate nucleus of the hypothalamus (ARH). To begin an analysis of various signaling pathways, protein kinase A and protein kinase C (PKC)-theta, whose signaling pathways have been implicated in the estradiol regulation of sexual receptivity, were examined. In the ARH sample, the increase in phospho-protein kinase A could not be confirmed by Western blotting, in either cytosolic or membrane fractions. However, the increase in phosphorylated PKCtheta seen with the pathway array was verified by Western blotting. To study whether rapid estradiol activation of PKC regulates the ARH-medial preoptic nucleus pathway regulating lordosis, mu-opioid receptor (MOR) internalization and lordosis reflex were tested. Blocking PKC in ARH with 2-[1-(3-dimethylaminopropyl)-1H-indol-3-yl]3-(1H-indol-3-yl) maleimide significantly attenuated estradiol-induced MOR internalization. Furthermore, disruption of PKC signaling within the ARH at the time of estradiol treatment significantly diminished the lordosis reflex. Moreover, blocking PKC prevented MOR internalization when the circuit was activated by the mGluR1a agonist, (RS)-3,5-dihydroxyphenylglycine. Activation of PKC with phorbol 12, 13-dibutyrate induced MOR internalization, indicating that PKC was a critical step for membrane ERalpha-initiated mGluR1a-mediated cell signaling and phorbol 12, 13-dibutyrate significantly facilitated the lordosis reflex. Together these findings indicate that rapid membrane ERalpha-mGluR1a interactions activate PKCtheta cell signaling, which regulates female sexual receptivity.
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Affiliation(s)
- Phoebe Dewing
- Department of Neurobiology, David Geffen School of Medicine at University of California, Los Angeles, Los Angeles, California 90095-1763, USA
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Petiti JP, De Paul AL, Gutiérrez S, Palmeri CM, Mukdsi JH, Torres AI. Activation of PKC epsilon induces lactotroph proliferation through ERK1/2 in response to phorbol ester. Mol Cell Endocrinol 2008; 289:77-84. [PMID: 18534741 DOI: 10.1016/j.mce.2008.04.015] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/28/2007] [Revised: 04/09/2008] [Accepted: 04/18/2008] [Indexed: 10/22/2022]
Abstract
The aim of this investigation was to contribute to current knowledge about intracellular mechanisms that are involved in lactotroph cell proliferation, by evaluating the role of PKCalpha, PKCepsilon and extracellular-signal regulated kinase (ERK) 1/2 in response to phorbol 12-myristate13-acetate (PMA). In primary pituitary cultures, the activation of protein kinase C (PKC) by PMA for 15 min stimulated lactotroph proliferation; whereas a prolonged activation for 3-8h diminished this proliferative effect. The use of PMA for 15 min-activated PKCepsilon and ERK1/2, whereas incubation with PMA for 3 h induced PKCalpha activation and attenuated the PMA-triggered phosphorylation of ERK1/2. The following inhibitors: PKCs (bisindolylmaleimide I), PKCepsilon (epsilonV1 peptide) and ERK1/2 (PD98059) prevented the mitogenic activity induced by PMA for 15 min. Lactotroph cells stimulated with PMA for 15 min showed a translocation of PKCepsilon to membrane compartment and nucleus. These results thus establish that PKCepsilon plays an essential role in the lactotroph proliferation induced by PMA by triggering signals that involve ERK1/2 activation.
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Affiliation(s)
- Juan Pablo Petiti
- Centro de Microscopía Electrónica, Facultad de Ciencias Médicas, Universidad Nacional de Córdoba, Haya de la Torre esq. Enrique Barros, 5000 Córdoba, Argentina.
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Vela J, Pérez-Millán MI, Becu-Villalobos D, Díaz-Torga G. Different kinases regulate activation of voltage-dependent calcium channels by depolarization in GH3 cells. Am J Physiol Cell Physiol 2007; 293:C951-9. [PMID: 17507432 DOI: 10.1152/ajpcell.00429.2006] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The L-type Ca2+ channel is the primary voltage-dependent Ca2+-influx pathway in many excitable and secretory cells, and direct phosphorylation by different kinases is one of the mechanisms involved in the regulation of its activity. The aim of this study was to evaluate the participation of Ser/Thr kinases and tyrosine kinases (TKs) in depolarization-induced Ca2+ influx in the endocrine somatomammotrope cell line GH3. Intracellular Ca2+ concentration ([Ca2+]i) was measured using a spectrofluorometric method with fura 2-AM, and 12.5 mM KCl (K+) was used as a depolarization stimulus. K+ induced an abrupt spike (peak) in [Ca2+]i that was abolished in the presence of nifedipine, showing that K+ enhances [Ca2+]i, preferably activating L-type Ca2+ channels. H89, a selective PKA inhibitor, significantly reduced depolarization-induced Ca2+ mobilization in a concentration-related manner when it was applied before or after K+, and okadaic acid, an inhibitor of Ser/Thr phosphatases, which has been shown to regulate PKA-stimulated L-type Ca2+ channels, increased K+-induced Ca2+ entry. When PKC was activated by PMA, the K+-evoked peak in [Ca2+]i, as well as the plateau phase, was significantly reduced, and chelerythrine (a PKC inhibitor) potentiated the K+-induced increase in [Ca2+]i, indicating an inhibitory role of PKC in voltage-dependent Ca2+ channel (VDCC) activity. Genistein, a TK inhibitor, reduced the K+-evoked increase in [Ca2+]i, but, unexpectedly, the tyrosine phosphatase inhibitor orthovanadate reduced not only basal Ca2+ levels but, also, Ca2+ influx during the plateau phase. Both results suggest that different TKs may act differentially on VDCC activation. Activation of receptor TKs with epidermal growth factor (EGF) or vascular endothelial growth factor potentiated K+-induced Ca2+ influx, and AG-1478 (an EGF receptor inhibitor) decreased it. However, inhibition of the non-receptor TK pp60 c-Src enhanced K+-induced Ca2+ influx. The present study strongly demonstrates that a complex equilibrium among different kinases and phosphatases regulates VDCC activity in the pituitary cell line GH3: PKA and receptor TKs, such as vascular endothelial growth factor receptor and EGF receptor, enhance depolarization-induced Ca2+ influx, whereas PKC and c-Src have an inhibitory effect. These kinases modulate membrane depolarization and may therefore participate in the regulation of a plethora of intracellular processes, such as hormone secretion, gene expression, protein synthesis, and cell proliferation, in pituitary cells.
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Affiliation(s)
- Jorge Vela
- Instituto de Biología y Medicina Experimental, CONICET, V. Obligado 2490, (1428Buenos Aires, Argentina
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Klausen C, Tsuchiya T, Chang JP, Habibi HR. PKC and ERK are differentially involved in gonadotropin-releasing hormone-induced growth hormone gene expression in the goldfish pituitary. Am J Physiol Regul Integr Comp Physiol 2005; 289:R1625-33. [PMID: 16109809 DOI: 10.1152/ajpregu.00188.2005] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Gonadotropin-releasing hormone (GnRH) is produced by the hypothalamus and stimulates the synthesis and secretion of gonadotropin hormones. In addition, GnRH also stimulates the production and secretion of growth hormone (GH) in some fish species and in humans with certain clinical disorders. In the goldfish pituitary, GH secretion and gene expression are regulated by two endogenous forms of GnRH known as salmon GnRH and chicken GnRH-II. It is well established that PKC mediates GnRH-stimulated GH secretion in the goldfish pituitary. In contrast, the signal transduction of GnRH-induced GH gene expression has not been elucidated in any model system. In this study, we demonstrate, for the first time, the presence of novel and atypical PKC isoforms in the pituitary of a fish. Moreover, our results indicate that conventional PKCα is present selectively in GH-producing cells. Treatment of primary cultures of dispersed goldfish pituitary cells with PKC activators (phorbol ester or diacylglycerol analog) did not affect basal or GnRH-induced GH mRNA levels, and two different inhibitors of PKC (calphostin C and GF109203X) did not reduce the effects of GnRH on GH gene expression. Together, these results suggest that, in contrast to secretion, conventional and novel PKCs are not involved in GnRH-stimulated increases in GH mRNA levels in the goldfish pituitary. Instead, PD98059 inhibited GnRH-induced GH gene expression, suggesting that the ERK signaling pathway is involved. The results presented here provide novel insights into the functional specificity of GnRH-induced signaling and the regulation of GH gene expression.
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Affiliation(s)
- Christian Klausen
- Dept. of Biological Sciences, Univ. of Calgary, Calgary, Alberta, Canada, T2N 1N4
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Chik CL, Li B, Karpinski E, Ho AK. Ceramide inhibits L-type calcium channel currents in GH3 cells. Mol Cell Endocrinol 2004; 218:175-83. [PMID: 15130522 DOI: 10.1016/j.mce.2003.10.048] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2003] [Accepted: 10/16/2003] [Indexed: 11/28/2022]
Abstract
In this study, we investigated the effect of ceramide on the L-type Ca2+ channel (L-channel) in GH3 cells. We found that C6-ceramide, but not C6-dihydroceramide, the inactive analogue, had an inhibitory effect on BayK 8644-stimulated GH release. Using patch clamp analysis, C6- and C2-ceramide, but not C6-dihydroceramide, were found to inhibit the L-channel current. Increasing intracellular ceramide level with sphingomyelinase also inhibited the L-channel current. The inhibitory effect of ceramide on the L-channel current was attenuated by calphostin C, a myristolated pseudosubstrate protein kinase C (PKC) inhibitor, and lavendustin A, a tyrosine kinase inhibitor. Combined treatment with lavendustin A and the myristolated PKC inhibitor blocked the effect of ceramide on the L-channel current. These results indicate that ceramide, a lipid messenger of the sphingomyelin pathway, is an important regulator of the L-channel in GH3 cells and both tyrosine kinase and PKC are involved in this effect of ceramide.
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Affiliation(s)
- C L Chik
- Department of Medicine, 7-33 Medical Sciences Building, Edmonton, Alta., Canada T6G 2H7.
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Helms MJ, Mohamed AA, MacEwan DJ. Modulated kinase activities in cells undergoing tumour necrosis factor-induced apoptotic cell death. FEBS Lett 2001; 505:68-74. [PMID: 11557044 DOI: 10.1016/s0014-5793(01)02779-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Tumour necrosis factor-alpha (TNF) has a variety of cellular effects including apoptotic and necrotic cytotoxicity. TNF activates a range of kinases, but their role in cytotoxic mechanisms is unclear. HeLa cells expressing elevated type II 75 kDa TNF receptor (TNFR2) protein, analysed by flow cytometry and Western analysis, showed altered c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (p38MAPK; but not MAPK) protein content and activation. There was greater JNK activation, but reduced p38MAPK activation in dying cells compared to those still to enter TNF-induced apoptosis. Moreover, cells displaying more rapid apoptosis possess higher levels of type I 55 kDa TNFR1 receptor isoform, but less TNFR2. These findings reveal differential kinase activation in TNF-induced apoptotic death.
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Affiliation(s)
- M J Helms
- Department of Biomedical Sciences, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK
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Zhang T, Mulvaney JM, Roberson MS. Activation of mitogen-activated protein kinase phosphatase 2 by gonadotropin-releasing hormone. Mol Cell Endocrinol 2001; 172:79-89. [PMID: 11165042 DOI: 10.1016/s0303-7207(00)00378-6] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The aim of these studies was to identify the signaling mechanism(s) that contribute to GnRH-induced expression of MAPK phosphatase (MKP)-2, a dual specificity phosphatase that selectively inactivates MAPKs. GnRH receptor activation induced MKP-2 expression in both clonal (alphaT3-1) and primary gonadotropes. Activation of PKC isozymes was sufficient and required for MKP-2 induction. Inhibition of the extracellular signal-regulated kinase (ERK) or c-Jun N-terminal kinase (JNK) but not the p38 MAPK cascade was sufficient to block GnRH-induced MKP-2 expression. Induction of MKP-2 by GnRH was dependent on elevation in intracellular Ca(2+). Inhibition of Ca(2+) influx through L-type voltage-gated calcium channels blocked GnRH-induced MKP-2 expression. Depletion of intracellular Ca(2+) stores with thapsigargin blocked MKP-2 activation by GnRH independent of ERK and JNK activity. These results support the conclusion that MKP-2 induction by GnRH occurs via MAPK-dependent and -independent pathways. One mechanism requires GnRH-induced ERK and JNK activation, while a second MAPK-independent pathway requires a thapsigargin-sensitive calcium signal.
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Affiliation(s)
- T Zhang
- Department of Biomedical Sciences, College of Veterinary Medicine, T6-008a Veterinary Research Tower, Cornell University, Ithaca, NY 14853, USA
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