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Trothen S, Teplitsky JE, Armstong RE, Zang RX, Lurie A, Mumby MJ, Edgar CR, Grol MW, Dikeakos JD. PACS-1 Interacts with TRPC3 and ESyt1 to Mediate Protein Trafficking while Promoting SOCE and Cooperatively Regulating Hormone Secretion. ACS OMEGA 2024; 9:35014-35027. [PMID: 39157130 PMCID: PMC11325417 DOI: 10.1021/acsomega.4c04998] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/27/2024] [Revised: 07/19/2024] [Accepted: 07/24/2024] [Indexed: 08/20/2024]
Abstract
Corticotropic cells of the anterior pituitary gland release adrenocorticotropic hormone (ACTH) in a regulated manner to promote the production of cortisol and androgens. The process of ACTH secretion is partly mediated by the phosphofurin acidic cluster sorting protein 1 (PACS-1); however, the underlying mechanisms behind this regulation remain unclear. Herein, we demonstrated PACS-1 interactions with the short transient receptor potential channel 3 (TRPC3) calcium transporter and the extended synaptotagmin-1 (ESyt1) endoplasmic reticulum-plasma membrane tethering protein. Importantly, PACS-1 promoted interactions between TRPC3 and ESyt1 and regulated their plasma membrane localization. Lastly, we demonstrated that PACS-1 is required for a proper store-operated calcium entry (SOCE) response and that ESyt1 regulates ACTH secretion through an unknown mechanism regulated by PACS-1. Overall, our study provides new insights into the physiological role PACS-1 plays in modulating intracellular calcium levels and regulating ACTH secretion in corticotropic cells.
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Affiliation(s)
- Steven
M. Trothen
- Department
of Microbiology and Immunology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, ON N6A 5C1, Canada
| | - Jack E. Teplitsky
- Department
of Microbiology and Immunology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, ON N6A 5C1, Canada
| | - Ryan E. Armstong
- Department
of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, ON N6A 5C1, Canada
| | - Rong Xuan Zang
- Department
of Microbiology and Immunology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, ON N6A 5C1, Canada
| | - Antony Lurie
- Department
of Microbiology and Immunology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, ON N6A 5C1, Canada
| | - Mitchell J. Mumby
- Department
of Microbiology and Immunology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, ON N6A 5C1, Canada
| | - Cassandra R. Edgar
- Department
of Microbiology and Immunology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, ON N6A 5C1, Canada
| | - Matthew W. Grol
- Department
of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, ON N6A 5C1, Canada
| | - Jimmy D. Dikeakos
- Department
of Microbiology and Immunology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, ON N6A 5C1, Canada
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Sodium background currents in endocrine/neuroendocrine cells: Towards unraveling channel identity and contribution in hormone secretion. Front Neuroendocrinol 2021; 63:100947. [PMID: 34592201 DOI: 10.1016/j.yfrne.2021.100947] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 09/03/2021] [Accepted: 09/23/2021] [Indexed: 02/04/2023]
Abstract
In endocrine/neuroendocrine tissues, excitability of secretory cells is patterned by the repertoire of ion channels and there is clear evidence that extracellular sodium (Na+) ions contribute to hormone secretion. While voltage-gated channels involved in action potential generation are well-described, the background 'leak' channels operating near the resting membrane potential are much less known, and in particular the channels supporting a background entry of Na+ ions. These background Na+ currents (called here 'INab') have the ability to modulate the resting membrane potential and subsequently affect action potential firing. Here we compile and analyze the data collected from three endocrine/neuroendocrine tissues: the anterior pituitary gland, the adrenal medulla and the endocrine pancreas. We also model how INab can be functionally involved in cellular excitability. Finally, towards deciphering the physiological role of INab in endocrine/neuroendocrine cells, its implication in hormone release is also discussed.
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Rojo-Ruiz J, Navas-Navarro P, Nuñez L, García-Sancho J, Alonso MT. Imaging of Endoplasmic Reticulum Ca 2+ in the Intact Pituitary Gland of Transgenic Mice Expressing a Low Affinity Ca 2+ Indicator. Front Endocrinol (Lausanne) 2020; 11:615777. [PMID: 33664709 PMCID: PMC7921146 DOI: 10.3389/fendo.2020.615777] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 12/15/2020] [Indexed: 11/13/2022] Open
Abstract
The adenohypophysis contains five secretory cell types (somatotrophs, lactotrophs, thyrotrophs, corticotrophs, and gonadotrophs), each secreting a different hormone, and controlled by different hypothalamic releasing hormones (HRHs). Exocytic secretion is regulated by cytosolic Ca2+ signals ([Ca2+]C), which can be generated either by Ca2+ entry through the plasma membrane and/or by Ca2+ release from the endoplasmic reticulum (ER). In addition, Ca2+ entry signals can eventually be amplified by ER release via calcium-induced calcium release (CICR). We have investigated the contribution of ER Ca2+ release to the action of physiological agonists in pituitary gland. Changes of [Ca2+] in the ER ([Ca2+]ER) were measured with the genetically encoded low-affinity Ca2+ sensor GAP3 targeted to the ER. We used a transgenic mouse strain that expressed erGAP3 driven by a ubiquitous promoter. Virtually all the pituitary cells were positive for the sensor. In order to mimick the physiological environment, intact pituitary glands or acute slices from the transgenic mouse were used to image [Ca2+]ER. [Ca2+]C was measured simultaneously with Rhod-2. Luteinizing hormone-releasing hormone (LHRH) or thyrotropin releasing hormone (TRH), two agonists known to elicit intracellular Ca2+ mobilization, provoked robust decreases of [Ca2+]ER and concomitant rises of [Ca2+]C. A smaller fraction of cells responded to thyrotropin releasing hormone (TRH). By contrast, depolarization with high K+ triggered a rise of [Ca2+]C without a decrease of [Ca2+]ER, indicating that the calcium-induced calcium-release (CICR) via ryanodine receptor amplification mechanism is not present in these cells. Our results show the potential of transgenic ER Ca2+ indicators as novel tools to explore intraorganellar Ca2+ dynamics in pituitary gland in situ.
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Store-operated Ca2+ entry and Ca2+ responses to hypothalamic releasing hormones in anterior pituitary cells from Orai1−/− and heptaTRPC knockout mice. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2019; 1866:1124-1136. [DOI: 10.1016/j.bbamcr.2018.11.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 11/02/2018] [Accepted: 11/05/2018] [Indexed: 01/25/2023]
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Götz V, Qiao S, Beck A, Boehm U. Transient receptor potential (TRP) channel function in the reproductive axis. Cell Calcium 2017; 67:138-147. [DOI: 10.1016/j.ceca.2017.04.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Revised: 04/19/2017] [Accepted: 04/19/2017] [Indexed: 10/19/2022]
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Duncan PJ, Shipston MJ. BK Channels and the Control of the Pituitary. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2016; 128:343-68. [PMID: 27238268 DOI: 10.1016/bs.irn.2016.03.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Abstract
The pituitary gland provides the important link between the nervous system and the endocrine system and regulates a diverse range of physiological functions. The pituitary is connected to the hypothalamus by the pituitary stalk and is comprised primarily of two lobes. The anterior lobe consists of five hormone-secreting cell types which are electrically excitable and display single-spike action potentials as well as complex bursting patterns. Bursting is of particular interest as it raises intracellular calcium to a greater extent than spiking and is believed to underlie secretagogue-induced hormone secretion. BK channels have been identified as a key regulator of bursting in anterior pituitary cells. Experimental data and mathematical modeling have demonstrated that BK activation during the upstroke of an action potential results in a prolonged depolarization and an increase in intracellular calcium. In contrast, the posterior lobe is primarily composed of axonal projections of magnocellular neurosecretory cells which extend from the supraoptic and paraventricular nuclei of the hypothalamus. In these neuroendocrine cells, BK channel activation results in a decrease in excitability and hormone secretion. The opposite effect of BK channels in the anterior and posterior pituitary highlights the diverse role of BK channels in regulating the activity of excitable cells. Further studies of pituitary cell excitability and the specific role of BK channels would lead to a greater understanding of how pituitary cell excitability is regulated by both hypothalamic secretagogues and negative feedback loops, and could ultimately lead to novel treatments to pituitary-related disorders.
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Affiliation(s)
- P J Duncan
- Centre for Integrative Physiology, College of Medicine & Veterinary Medicine, University of Edinburgh, Edinburgh, United Kingdom.
| | - M J Shipston
- Centre for Integrative Physiology, College of Medicine & Veterinary Medicine, University of Edinburgh, Edinburgh, United Kingdom
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Zhou M, Suzuki R, Ishizawa A, Tanaka O, Yasuoka Y, Kanatsu Y, Kawahara K, Abe H. Localization of ATP-sensitive K+ channel subunits in rat pituitary gland . ACTA ACUST UNITED AC 2016. [DOI: 10.1679/aohc.76.53] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Ming Zhou
- Department of Anatomy, Akita University Graduate School of Medicine,
| | - Ryoji Suzuki
- Department of Anatomy, Akita University Graduate School of Medicine,
| | - Akimitsu Ishizawa
- Department of Anatomy, Akita University Graduate School of Medicine,
| | - Osamu Tanaka
- Department of Anatomy, Tokai University School of Medicine,
| | - Yukiko Yasuoka
- Department of Physiology,Kitasato University Graduate School of Medical Sciences,
- Department of Cellular & Molecular Physiology, Kitasato University Graduate School of Medical Sciences,
| | - Yoshinori Kanatsu
- Department of Anatomy, Akita University Graduate School of Medicine,
| | - Katsumasa Kawahara
- Department of Physiology,Kitasato University Graduate School of Medical Sciences,
- Department of Cellular & Molecular Physiology, Kitasato University Graduate School of Medical Sciences,
| | - Hiroshi Abe
- Department of Anatomy, Akita University Graduate School of Medicine,
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Stojilkovic SS, Kretschmannova K, Tomić M, Stratakis CA. Dependence of the excitability of pituitary cells on cyclic nucleotides. J Neuroendocrinol 2012; 24:1183-200. [PMID: 22564128 PMCID: PMC3421050 DOI: 10.1111/j.1365-2826.2012.02335.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Cyclic 3',5'-adenosine monophosphate and cyclic 3',5'-guanosine monophosphate are intracellular (second) messengers that are produced from the nucleotide triphosphates by a family of enzymes consisting of adenylyl and guanylyl cyclases. These enzymes are involved in a broad array of signal transduction pathways mediated by the cyclic nucleotide monophosphates and their kinases, which control multiple aspects of cell function through the phosphorylation of protein substrates. We review the findings and working hypotheses on the role of the cyclic nucleotides and their kinases in the control of electrical activity of the endocrine pituitary cells and the plasma membrane channels involved in this process.
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Affiliation(s)
- S S Stojilkovic
- Sections on Cellular Signalling and Endocrinology and Genetics, The Eunice Kennedy Shiver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
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Tomić M, Kucka M, Kretschmannova K, Li S, Nesterova M, Stratakis CA, Stojilkovic SS. Role of nonselective cation channels in spontaneous and protein kinase A-stimulated calcium signaling in pituitary cells. Am J Physiol Endocrinol Metab 2011; 301:E370-9. [PMID: 21586701 PMCID: PMC3154538 DOI: 10.1152/ajpendo.00130.2011] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Several receptors linked to the adenylyl cyclase signaling pathway stimulate electrical activity and calcium influx in endocrine pituitary cells, and a role for an unidentified sodium-conducting channel in this process has been proposed. Here we show that forskolin dose-dependently increases cAMP production and facilitates calcium influx in about 30% of rat and mouse pituitary cells at its maximal concentration. The stimulatory effect of forskolin on calcium influx was lost in cells with inhibited PKA (cAMP-dependent protein kinase) and in cells that were haploinsufficient for the main PKA regulatory subunit but was preserved in cells that were also haploinsufficient for the main PKA catalytic subunit. Spontaneous and forskolin-stimulated calcium influx was present in cells with inhibited voltage-gated sodium and hyperpolarization-activated cation channels but not in cells bathed in medium, in which sodium was replaced with organic cations. Consistent with the role of sodium-conducting nonselective cation channels in PKA-stimulated Ca(2+) influx, cAMP induced a slowly developing current with a reversal potential of about 0 mV. Two TRP (transient receptor potential) channel blockers, SKF96365 and 2-APB, as well as flufenamic acid, an inhibitor of nonselective cation channels, also inhibited spontaneous and forskolin-stimulated electrical activity and calcium influx. Quantitative RT-PCR analysis indicated the expression of mRNA transcripts for TRPC1 >> TRPC6 > TRPC4 > TRPC5 > TRPC3 in rat pituitary cells. These experiments suggest that in pituitary cells constitutively active cation channels are stimulated further by PKA and contribute to calcium signaling indirectly by controlling the pacemaking depolarization in a sodium-dependent manner and directly by conducting calcium.
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Affiliation(s)
- Melanija Tomić
- National Institute of Child Health and Human Development/NIH, 49 Convent Dr., Bethesda, MD 20892-4510, USA
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Stutzmann GE, Mattson MP. Endoplasmic reticulum Ca(2+) handling in excitable cells in health and disease. Pharmacol Rev 2011; 63:700-27. [PMID: 21737534 DOI: 10.1124/pr.110.003814] [Citation(s) in RCA: 183] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The endoplasmic reticulum (ER) is a morphologically and functionally diverse organelle capable of integrating multiple extracellular and internal signals and generating adaptive cellular responses. It plays fundamental roles in protein synthesis and folding and in cellular responses to metabolic and proteotoxic stress. In addition, the ER stores and releases Ca(2+) in sophisticated scenarios that regulate a range of processes in excitable cells throughout the body, including muscle contraction and relaxation, endocrine regulation of metabolism, learning and memory, and cell death. One or more Ca(2+) ATPases and two types of ER membrane Ca(2+) channels (inositol trisphosphate and ryanodine receptors) are the major proteins involved in ER Ca(2+) uptake and release, respectively. There are also direct and indirect interactions of ER Ca(2+) stores with plasma membrane and mitochondrial Ca(2+)-regulating systems. Pharmacological agents that selectively modify ER Ca(2+) release or uptake have enabled studies that revealed many different physiological roles for ER Ca(2+) signaling. Several inherited diseases are caused by mutations in ER Ca(2+)-regulating proteins, and perturbed ER Ca(2+) homeostasis is implicated in a range of acquired disorders. Preclinical investigations suggest a therapeutic potential for use of agents that target ER Ca(2+) handling systems of excitable cells in disorders ranging from cardiac arrhythmias and skeletal muscle myopathies to Alzheimer disease.
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Affiliation(s)
- Grace E Stutzmann
- Department of Neuroscience, Rosalind Franklin University/The Chicago Medical School, 3333 Green Bay Road, North Chicago, IL 60064, USA.
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11
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Abstract
Endocrine pituitary cells are neuronlike; they express numerous voltage-gated sodium, calcium, potassium, and chloride channels and fire action potentials spontaneously, accompanied by a rise in intracellular calcium. In some cells, spontaneous electrical activity is sufficient to drive the intracellular calcium concentration above the threshold for stimulus-secretion and stimulus-transcription coupling. In others, the function of these action potentials is to maintain the cells in a responsive state with cytosolic calcium near, but below, the threshold level. Some pituitary cells also express gap junction channels, which could be used for intercellular Ca(2+) signaling in these cells. Endocrine cells also express extracellular ligand-gated ion channels, and their activation by hypothalamic and intrapituitary hormones leads to amplification of the pacemaking activity and facilitation of calcium influx and hormone release. These cells also express numerous G protein-coupled receptors, which can stimulate or silence electrical activity and action potential-dependent calcium influx and hormone release. Other members of this receptor family can activate calcium channels in the endoplasmic reticulum, leading to a cell type-specific modulation of electrical activity. This review summarizes recent findings in this field and our current understanding of the complex relationship between voltage-gated ion channels, ligand-gated ion channels, gap junction channels, and G protein-coupled receptors in pituitary cells.
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Affiliation(s)
- Stanko S Stojilkovic
- Program in Developmental Neuroscience, National Institute of Child Health and Human Development, National Institutes of Health, Building 49, Room 6A-36, 49 Convent Drive, Bethesda, Maryland 20892-4510, USA.
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Bae MY, Cho JH, Choi IS, Park HM, Lee MG, Kim DH, Jang IS. Compound K, a metabolite of ginsenosides, facilitates spontaneous GABA release onto CA3 pyramidal neurons. J Neurochem 2010; 114:1085-96. [PMID: 20524959 DOI: 10.1111/j.1471-4159.2010.06833.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Ginsenoside Rb1, a major ingredient of ginseng saponins, can affect various brain functions, including learning and memory. When ingested orally, ginsenoside Rb1 is not found in plasma as well as urine, but its metabolite compound K (ComK) reaches the systemic circulation in animals and human. Nevertheless, the pharmacological actions of ComK are still poorly known. In the present study, we investigated the effect of ComK on GABAergic spontaneous miniature inhibitory post-synaptic currents (mIPSCs) in acutely isolated rat hippocampal CA3 pyramidal neurons using a conventional whole-cell patch-clamp technique. While ComK significantly increased mIPSC frequency in a concentration-dependent manner, it had no effect on the current amplitude, suggesting that ComK acts pre-synaptically to increase the probability of spontaneous GABA release. ComK still increased mIPSC frequency even in a Ca(2+) -free external solution, suggesting that the ComK-induced increase spontaneous GABA release is not related to Ca(2+) influx from the extracellular space. However, the ComK-induced increase mIPSC frequency was significantly decreased after the blockade of either sarcoplasmic/endoplasmic reticulum Ca(2+) -ATPase or Ca(2+) release channels. These results strongly suggest that ComK enhances spontaneous GABA release by increasing intraterminal Ca(2+) concentration via Ca(2+) release from pre-synaptic Ca(2+) stores. The ComK-induced modulation of inhibitory transmission onto CA3 pyramidal neurons could have a broad impact on the excitability of CA3 pyramidal neurons and affect the physiological functions mediated by the hippocampus.
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Affiliation(s)
- Man-Yeol Bae
- Department of Pharmacology, School of Dentistry, Kyungpook National University, Jung-gu, Daegu, Korea
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