1
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A tapt1 knock-out zebrafish line with aberrant lens development and impaired vision models human early-onset cataract. Hum Genet 2023; 142:457-476. [PMID: 36697720 DOI: 10.1007/s00439-022-02518-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Accepted: 12/19/2022] [Indexed: 01/27/2023]
Abstract
Bi-allelic mutations in the gene coding for human trans-membrane anterior-posterior transformation protein 1 (TAPT1) result in a broad phenotypic spectrum, ranging from syndromic disease with severe skeletal and congenital abnormalities to isolated early-onset cataract. We present here the first patient with a frameshift mutation in the TAPT1 gene, resulting in both bilateral early-onset cataract and skeletal abnormalities, in addition to several dysmorphic features, in this way further expanding the phenotypic spectrum associated with TAPT1 mutations. A tapt1a/tapt1b double knock-out (KO) zebrafish model generated by CRISPR/Cas9 gene editing revealed an early larval phenotype with eye malformations, loss of vision, increased photokinetics and hyperpigmentation, without visible skeletal involvement. Ultrastructural analysis of the eyes showed a smaller condensed lens, loss of integrity of the lens capsule with formation of a secondary lens and hyperplasia of the cells in the ganglion and inner plexiform layers of the retina. Transcriptomic analysis pointed to an impaired lens development with aberrant expression of many of the crystallin and other lens-specific genes. Furthermore, the phototransduction and visual perception pathways were found to be significantly disturbed. Differences in light perception are likely the cause of the increased dark photokinetics and generalized hyperpigmentation observed in this zebrafish model. In conclusion, this study validates TAPT1 as a new gene for early-onset cataract and sheds light on its ultrastructural and molecular characteristics.
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2
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Fernandes B, Cavaco-Paulo A, Matamá T. A Comprehensive Review of Mammalian Pigmentation: Paving the Way for Innovative Hair Colour-Changing Cosmetics. BIOLOGY 2023; 12:biology12020290. [PMID: 36829566 PMCID: PMC9953601 DOI: 10.3390/biology12020290] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Revised: 01/26/2023] [Accepted: 02/09/2023] [Indexed: 02/15/2023]
Abstract
The natural colour of hair shafts is formed at the bulb of hair follicles, and it is coupled to the hair growth cycle. Three critical processes must happen for efficient pigmentation: (1) melanosome biogenesis in neural crest-derived melanocytes, (2) the biochemical synthesis of melanins (melanogenesis) inside melanosomes, and (3) the transfer of melanin granules to surrounding pre-cortical keratinocytes for their incorporation into nascent hair fibres. All these steps are under complex genetic control. The array of natural hair colour shades are ascribed to polymorphisms in several pigmentary genes. A myriad of factors acting via autocrine, paracrine, and endocrine mechanisms also contributes for hair colour diversity. Given the enormous social and cosmetic importance attributed to hair colour, hair dyeing is today a common practice. Nonetheless, the adverse effects of the long-term usage of such cosmetic procedures demand the development of new methods for colour change. In this context, case reports of hair lightening, darkening and repigmentation as a side-effect of the therapeutic usage of many drugs substantiate the possibility to tune hair colour by interfering with the biology of follicular pigmentary units. By scrutinizing mammalian pigmentation, this review pinpoints key targetable processes for the development of innovative cosmetics that can safely change the hair colour from the inside out.
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Affiliation(s)
- Bruno Fernandes
- CEB—Centre of Biological Engineering, University of Minho, Campus of Gualtar, 4710-057 Braga, Portugal
| | - Artur Cavaco-Paulo
- CEB—Centre of Biological Engineering, University of Minho, Campus of Gualtar, 4710-057 Braga, Portugal
- LABBELS—Associate Laboratory, 4710-057 Braga, Portugal
- Correspondence: (A.C.-P.); (T.M.); Tel.: +351-253-604-409 (A.C.-P.); +351-253-601-599 (T.M.)
| | - Teresa Matamá
- CEB—Centre of Biological Engineering, University of Minho, Campus of Gualtar, 4710-057 Braga, Portugal
- LABBELS—Associate Laboratory, 4710-057 Braga, Portugal
- Correspondence: (A.C.-P.); (T.M.); Tel.: +351-253-604-409 (A.C.-P.); +351-253-601-599 (T.M.)
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3
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Ciaglia T, Vestuto V, Bertamino A, González-Muñiz R, Gómez-Monterrey I. On the modulation of TRPM channels: Current perspectives and anticancer therapeutic implications. Front Oncol 2023; 12:1065935. [PMID: 36844925 PMCID: PMC9948629 DOI: 10.3389/fonc.2022.1065935] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Accepted: 12/15/2022] [Indexed: 02/11/2023] Open
Abstract
The transient melastatin receptor potential (TRPM) ion channel subfamily functions as cellular sensors and transducers of critical biological signal pathways by regulating ion homeostasis. Some members of TRPM have been cloned from cancerous tissues, and their abnormal expressions in various solid malignancies have been correlated with cancer cell growth, survival, or death. Recent evidence also highlights the mechanisms underlying the role of TRPMs in tumor epithelial-mesenchymal transition (EMT), autophagy, and cancer metabolic reprogramming. These implications support TRPM channels as potential molecular targets and their modulation as an innovative therapeutic approach against cancer. Here, we discuss the general characteristics of the different TRPMs, focusing on current knowledge about the connection between TRPM channels and critical features of cancer. We also cover TRPM modulators used as pharmaceutical tools in biological trials and an indication of the only clinical trial with a TRPM modulator about cancer. To conclude, the authors describe the prospects for TRPM channels in oncology.
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Affiliation(s)
- Tania Ciaglia
- Dipartimento di Farmacia (DIFARMA), Università degli Studi di Salerno, Fisciano, Italy
| | - Vincenzo Vestuto
- Dipartimento di Farmacia (DIFARMA), Università degli Studi di Salerno, Fisciano, Italy
| | - Alessia Bertamino
- Dipartimento di Farmacia (DIFARMA), Università degli Studi di Salerno, Fisciano, Italy
| | - Rosario González-Muñiz
- Departamento de Biomiméticos, Instituto de Química Médica, Madrid, Spain,*Correspondence: Isabel Gómez-Monterrey, ; Rosario González-Muñiz,
| | - Isabel Gómez-Monterrey
- Dipartimento di Farmacia, Università degli Studi di Napoli “Federico II”, Naples, Italy,*Correspondence: Isabel Gómez-Monterrey, ; Rosario González-Muñiz,
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4
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Križaj D, Cordeiro S, Strauß O. Retinal TRP channels: Cell-type-specific regulators of retinal homeostasis and multimodal integration. Prog Retin Eye Res 2023; 92:101114. [PMID: 36163161 PMCID: PMC9897210 DOI: 10.1016/j.preteyeres.2022.101114] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 08/03/2022] [Accepted: 08/08/2022] [Indexed: 02/05/2023]
Abstract
Transient receptor potential (TRP) channels are a widely expressed family of 28 evolutionarily conserved cationic ion channels that operate as primary detectors of chemical and physical stimuli and secondary effectors of metabotropic and ionotropic receptors. In vertebrates, the channels are grouped into six related families: TRPC, TRPV, TRPM, TRPA, TRPML, and TRPP. As sensory transducers, TRP channels are ubiquitously expressed across the body and the CNS, mediating critical functions in mechanosensation, nociception, chemosensing, thermosensing, and phototransduction. This article surveys current knowledge about the expression and function of the TRP family in vertebrate retinas, which, while dedicated to transduction and transmission of visual information, are highly susceptible to non-visual stimuli. Every retinal cell expresses multiple TRP subunits, with recent evidence establishing their critical roles in paradigmatic aspects of vertebrate vision that include TRPM1-dependent transduction of ON bipolar signaling, TRPC6/7-mediated ganglion cell phototransduction, TRP/TRPL phototransduction in Drosophila and TRPV4-dependent osmoregulation, mechanotransduction, and regulation of inner and outer blood-retina barriers. TRP channels tune light-dependent and independent functions of retinal circuits by modulating the intracellular concentration of the 2nd messenger calcium, with emerging evidence implicating specific subunits in the pathogenesis of debilitating diseases such as glaucoma, ocular trauma, diabetic retinopathy, and ischemia. Elucidation of TRP channel involvement in retinal biology will yield rewards in terms of fundamental understanding of vertebrate vision and therapeutic targeting to treat diseases caused by channel dysfunction or over-activation.
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Affiliation(s)
- David Križaj
- Departments of Ophthalmology, Neurobiology, and Bioengineering, University of Utah, Salt Lake City, USA
| | - Soenke Cordeiro
- Institute of Physiology, Faculty of Medicine, Christian-Albrechts-University Kiel, Germany
| | - Olaf Strauß
- Experimental Ophthalmology, Department of Ophthalmology, Charité - Universitätsmedizin Berlin, a Corporate Member of Freie Universität, Humboldt-University, The Berlin Institute of Health, Berlin, Germany.
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5
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Cao Y, Fajardo D, Guerrero-Given D, Samuel MA, Ohtsuka T, Boye SE, Kamasawa N, Martemyanov KA. Post-developmental plasticity of the primary rod pathway allows restoration of visually guided behaviors. Curr Biol 2022; 32:4783-4796.e3. [PMID: 36179691 PMCID: PMC9691582 DOI: 10.1016/j.cub.2022.09.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 08/17/2022] [Accepted: 09/08/2022] [Indexed: 01/24/2023]
Abstract
The formation of neural circuits occurs in a programmed fashion, but proper activity in the circuit is essential for refining the organization necessary for driving complex behavioral tasks. In the retina, sensory deprivation during the critical period of development is well known to perturb the organization of the visual circuit making the animals unable to use vision for behavior. However, the extent of plasticity, molecular factors involved, and malleability of individual channels in the circuit to manipulations outside of the critical period are not well understood. In this study, we selectively disconnected and reconnected rod photoreceptors in mature animals after completion of the retina circuit development. We found that introducing synaptic rod photoreceptor input post-developmentally allowed their integration into the circuit both anatomically and functionally. Remarkably, adult mice with newly integrated rod photoreceptors gained high-sensitivity vision, even when it was absent from birth. These observations reveal plasticity of the retina circuit organization after closure of the critical period and encourage the development of vision restoration strategies for congenital blinding disorders.
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Affiliation(s)
- Yan Cao
- Department of Neuroscience, UF Scripps Biomedical Research, Jupiter, FL 33458, USA
| | - Diego Fajardo
- Division of Cellular and Molecular Therapy, Department of Pediatrics, University of Florida, Gainesville, FL, USA
| | - Debbie Guerrero-Given
- The Imaging Center, Electron Microscopy Core Facility, Max Planck Florida Institute, 1 Max Planck Way, Jupiter, FL 33458, USA
| | - Melanie A Samuel
- Department of Neuroscience, Huffington Center on Aging, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Toshihisa Ohtsuka
- Department of Biochemistry, Graduate School of Medicine, Faculty of Medicine, University of Yamanashi, Yamanashi 409-3898, Japan
| | - Shannon E Boye
- Division of Cellular and Molecular Therapy, Department of Pediatrics, University of Florida, Gainesville, FL, USA
| | - Naomi Kamasawa
- The Imaging Center, Electron Microscopy Core Facility, Max Planck Florida Institute, 1 Max Planck Way, Jupiter, FL 33458, USA
| | - Kirill A Martemyanov
- Department of Neuroscience, UF Scripps Biomedical Research, Jupiter, FL 33458, USA.
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6
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Kazandzhieva K, Mammadova-Bach E, Dietrich A, Gudermann T, Braun A. TRP channel function in platelets and megakaryocytes: basic mechanisms and pathophysiological impact. Pharmacol Ther 2022; 237:108164. [PMID: 35247518 DOI: 10.1016/j.pharmthera.2022.108164] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 01/29/2022] [Accepted: 02/28/2022] [Indexed: 12/30/2022]
Abstract
Transient receptor potential (TRP) proteins form a superfamily of cation channels that are expressed in a wide range of tissues and cell types. During the last years, great progress has been made in understanding the molecular complexity and the functions of TRP channels in diverse cellular processes, including cell proliferation, migration, adhesion and activation. The diversity of functions depends on multiple regulatory mechanisms by which TRP channels regulate Ca2+ entry mechanisms and intracellular Ca2+ dynamics, either through membrane depolarization involving cation influx or store- and receptor-operated mechanisms. Abnormal function or expression of TRP channels results in vascular pathologies, including hypertension, ischemic stroke and inflammatory disorders through effects on vascular cells, including the components of blood vessels and platelets. Moreover, some TRP family members also regulate megakaryopoiesis and platelet production, indicating a complex role of TRP channels in pathophysiological conditions. In this review, we describe potential roles of TRP channels in megakaryocytes and platelets, as well as their contribution to diseases such as thrombocytopenia, thrombosis and stroke. We also critically discuss the potential of TRP channels as possible targets for disease prevention and treatment.
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Affiliation(s)
- Kalina Kazandzhieva
- Walther-Straub-Institute for Pharmacology and Toxicology, Ludwig-Maximilians-University, Munich, Germany
| | - Elmina Mammadova-Bach
- Walther-Straub-Institute for Pharmacology and Toxicology, Ludwig-Maximilians-University, Munich, Germany; Division of Nephrology, Department of Medicine IV, Ludwig-Maximilians-University Hospital, Munich, Germany
| | - Alexander Dietrich
- Walther-Straub-Institute for Pharmacology and Toxicology, Ludwig-Maximilians-University, Munich, Germany; German Center for Lung Research (DZL), Munich, Germany
| | - Thomas Gudermann
- Walther-Straub-Institute for Pharmacology and Toxicology, Ludwig-Maximilians-University, Munich, Germany; German Center for Lung Research (DZL), Munich, Germany.
| | - Attila Braun
- Walther-Straub-Institute for Pharmacology and Toxicology, Ludwig-Maximilians-University, Munich, Germany.
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7
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Palazzo E, Boccella S, Marabese I, Perrone M, Belardo C, Iannotta M, Scuteri D, De Dominicis E, Pagano M, Infantino R, Bagetta G, Maione S. Homo-AMPA in the periaqueductal grey modulates pain and rostral ventromedial medulla activity in diabetic neuropathic mice. Neuropharmacology 2022; 212:109047. [DOI: 10.1016/j.neuropharm.2022.109047] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 02/22/2022] [Accepted: 03/26/2022] [Indexed: 12/21/2022]
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8
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Enkhtaivan E, Lee CH. Role of Amine Neurotransmitters and Their Receptors in Skin Pigmentation: Therapeutic Implication. Int J Mol Sci 2021; 22:ijms22158071. [PMID: 34360837 PMCID: PMC8348573 DOI: 10.3390/ijms22158071] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Revised: 07/09/2021] [Accepted: 07/24/2021] [Indexed: 12/27/2022] Open
Abstract
Skin pigmentation can occur due to increased melanin, including melanocyte proliferation, melanin biosynthesis, or melanocyte migration. There are many factors that influence the melanin production process, but the role of neurotransmitters in this process is still unclear. We found that histamine and serotonin influence the different stages of melanogenesis and melanogenesis, which increase melanogenesis. Since then, several related papers have been published, and from these papers, it has been recognised that the role of neurotransmitters in skin-pigment-related diseases needs to be summarised. By introducing the role of neurotransmitters in the regulation of various pigment disorders, including vitiligo and melasma, through this review, many researchers can be expected to try to apply neurotransmitter-related agonists and antagonists as treatments for skin pigment disorders.
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9
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Shi R, Fu Y, Zhao D, Boczek T, Wang W, Guo F. Cell death modulation by transient receptor potential melastatin channels TRPM2 and TRPM7 and their underlying molecular mechanisms. Biochem Pharmacol 2021; 190:114664. [PMID: 34175300 DOI: 10.1016/j.bcp.2021.114664] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 06/21/2021] [Accepted: 06/22/2021] [Indexed: 10/21/2022]
Abstract
Transient receptor potential melastatin (TRPM) channels are members of the transient receptor potential (TRP) channels, a family of evolutionarily conserved integral membrane proteins. TRPM channels are nonselective cation channels, mediating the influx of various ions including Ca2+, Na+ and Zn2+. The function of TRPM channels is vital for cell proliferation, cell development and cell death. Cell death is a key procedure during embryonic development, organism homeostasis, aging and disease. The category of cell death modalities, beyond the traditionally defined concepts of necrosis, autophagy, and apoptosis, were extended with the discovery of pyroptosis, necroptosis and ferroptosis. As upstream signaling regulators of cell death, TRPM channels have been involved inrelevant pathologies. In this review, we introduced several cell death modalities, then summarized the contribution of TRPM channels (especially TRPM2 and TRPM7) to different cell death modalities and discussed the underlying regulatory mechanisms. Our work highlighted the possibility of TRPM channels as potential therapeutic targets in cell death-related diseases.
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Affiliation(s)
- Ruixue Shi
- Department of Pharmaceutical Toxicology, School of Pharmacy, China Medical University, Shenyang 110122, China
| | - Yu Fu
- Department of Pharmaceutical Toxicology, School of Pharmacy, China Medical University, Shenyang 110122, China
| | - Dongyi Zhao
- The University of Tokyo, Department of Pharmaceutical Science, 1130033, Japan
| | - Tomasz Boczek
- Department of Molecular Neurochemistry, Medical University of Lodz, 92215, Poland.
| | - Wuyang Wang
- Jiangsu Province Key Laboratory of Anesthesiology, Xuzhou Medical University, Xuzhou 221004, China.
| | - Feng Guo
- Department of Pharmaceutical Toxicology, School of Pharmacy, China Medical University, Shenyang 110122, China.
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10
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Jimenez I, Prado Y, Marchant F, Otero C, Eltit F, Cabello-Verrugio C, Cerda O, Simon F. TRPM Channels in Human Diseases. Cells 2020; 9:E2604. [PMID: 33291725 PMCID: PMC7761947 DOI: 10.3390/cells9122604] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 11/30/2020] [Accepted: 12/01/2020] [Indexed: 12/11/2022] Open
Abstract
The transient receptor potential melastatin (TRPM) subfamily belongs to the TRP cation channels family. Since the first cloning of TRPM1 in 1989, tremendous progress has been made in identifying novel members of the TRPM subfamily and their functions. The TRPM subfamily is composed of eight members consisting of four six-transmembrane domain subunits, resulting in homomeric or heteromeric channels. From a structural point of view, based on the homology sequence of the coiled-coil in the C-terminus, the eight TRPM members are clustered into four groups: TRPM1/M3, M2/M8, M4/M5 and M6/M7. TRPM subfamily members have been involved in several physiological functions. However, they are also linked to diverse pathophysiological human processes. Alterations in the expression and function of TRPM subfamily ion channels might generate several human diseases including cardiovascular and neurodegenerative alterations, organ dysfunction, cancer and many other channelopathies. These effects position them as remarkable putative targets for novel diagnostic strategies, drug design and therapeutic approaches. Here, we review the current knowledge about the main characteristics of all members of the TRPM family, focusing on their actions in human diseases.
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Affiliation(s)
- Ivanka Jimenez
- Faculty of Life Science, Universidad Andrés Bello, Santiago 8370186, Chile; (I.J.); (Y.P.); (F.M.); (C.C.-V.)
- Millennium Nucleus of Ion Channel-Associated Diseases (MiNICAD), Universidad de Chile, Santiago 8380453, Chile;
| | - Yolanda Prado
- Faculty of Life Science, Universidad Andrés Bello, Santiago 8370186, Chile; (I.J.); (Y.P.); (F.M.); (C.C.-V.)
- Millennium Nucleus of Ion Channel-Associated Diseases (MiNICAD), Universidad de Chile, Santiago 8380453, Chile;
| | - Felipe Marchant
- Faculty of Life Science, Universidad Andrés Bello, Santiago 8370186, Chile; (I.J.); (Y.P.); (F.M.); (C.C.-V.)
- Millennium Nucleus of Ion Channel-Associated Diseases (MiNICAD), Universidad de Chile, Santiago 8380453, Chile;
| | - Carolina Otero
- Faculty of Medicine, School of Chemistry and Pharmacy, Universidad Andrés Bello, Santiago 8370186, Chile;
| | - Felipe Eltit
- Vancouver Prostate Centre, Vancouver, BC V6Z 1Y6, Canada;
- Department of Urological Sciences, University of British Columbia, Vancouver, BC V6Z 1Y6, Canada
| | - Claudio Cabello-Verrugio
- Faculty of Life Science, Universidad Andrés Bello, Santiago 8370186, Chile; (I.J.); (Y.P.); (F.M.); (C.C.-V.)
- Center for the Development of Nanoscience and Nanotechnology (CEDENNA), Universidad de Santiago de Chile, Santiago 7560484, Chile
- Millennium Institute on Immunology and Immunotherapy, Santiago 8370146, Chile
| | - Oscar Cerda
- Millennium Nucleus of Ion Channel-Associated Diseases (MiNICAD), Universidad de Chile, Santiago 8380453, Chile;
- Program of Cellular and Molecular Biology, Institute of Biomedical Sciences (ICBM), Faculty of Medicine, Universidad de Chile, Santiago 8380453, Chile
| | - Felipe Simon
- Faculty of Life Science, Universidad Andrés Bello, Santiago 8370186, Chile; (I.J.); (Y.P.); (F.M.); (C.C.-V.)
- Millennium Nucleus of Ion Channel-Associated Diseases (MiNICAD), Universidad de Chile, Santiago 8380453, Chile;
- Millennium Institute on Immunology and Immunotherapy, Santiago 8370146, Chile
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11
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Palazzo E, Boccella S, Marabese I, Pierretti G, Guida F, Maione S. The Cold Case of Metabotropic Glutamate Receptor 6: Unjust Detention in the Retina? Curr Neuropharmacol 2020; 18:120-125. [PMID: 31573889 PMCID: PMC7324884 DOI: 10.2174/1570159x17666191001141849] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Revised: 08/20/2019] [Accepted: 09/29/2019] [Indexed: 02/03/2023] Open
Abstract
It is a common opinion that metabotropic glutamate receptor subtype 6 (mGluR6) is expressed exclusively in the retina, and in particular in the dendrites of ON-bipolar cells. Glutamate released in darkness from photoreceptors activates mGluR6, which is negatively associated with a membrane non-selective cation channel, the transient receptor potential melanoma-related 1, TRPM1, resulting in cell hyperpolarization. The evidence that mGluR6 is expressed not only in the retina but also in other tissues and cell populations has accumulated over time. The expression of mGluR6 has been identified in microglia, bone marrow stromal and prostate cancer cells, B lymphocytes, melanocytes and keratinocytes and non-neural tissues such as testis, kidney, cornea, conjunctiva, and eyelid. The receptor also appears to be expressed in brain areas, such as the hypothalamus, cortex, hippocampus, nucleus of tractus solitarius, superior colliculus, axons of the corpus callosum and accessory olfactory bulb. The pharmacological activation of mGluR6 in the hippocampus produced an anxiolytic-like effect and in the periaqueductal gray analgesic potential. This review aims to collect all the evidence on the expression and functioning of mGluR6 outside the retina that has been accumulated over the years for a broader view of the potential of the receptor whose retinal confinement appears understimated.
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Affiliation(s)
- E Palazzo
- Department of Experimental Medicine, Pharmacology Division, University of Campania "L. Vanvitelli", Naples, Italy
| | - S Boccella
- Department of Experimental Medicine, Pharmacology Division, University of Campania "L. Vanvitelli", Naples, Italy
| | - I Marabese
- Department of Experimental Medicine, Pharmacology Division, University of Campania "L. Vanvitelli", Naples, Italy
| | - G Pierretti
- Department of Plastic Surgery, University of Campania "L. Vanvitelli", Naples, Italy
| | - F Guida
- Department of Experimental Medicine, Pharmacology Division, University of Campania "L. Vanvitelli", Naples, Italy
| | - S Maione
- Department of Experimental Medicine, Pharmacology Division, University of Campania "L. Vanvitelli", Naples, Italy
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12
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Screening of genes coupled to heat response in Mongolian and Dorper sheep breeds. Biologia (Bratisl) 2020. [DOI: 10.2478/s11756-020-00616-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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13
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Glutamate receptors in domestication and modern human evolution. Neurosci Biobehav Rev 2020; 108:341-357. [DOI: 10.1016/j.neubiorev.2019.10.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2019] [Revised: 09/28/2019] [Accepted: 10/07/2019] [Indexed: 02/08/2023]
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14
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Petit A, Knabe L, Khelloufi K, Jory M, Gras D, Cabon Y, Begg M, Richard S, Massiera G, Chanez P, Vachier I, Bourdin A. Bronchial Epithelial Calcium Metabolism Impairment in Smokers and Chronic Obstructive Pulmonary Disease. Decreased ORAI3 Signaling. Am J Respir Cell Mol Biol 2019; 61:501-511. [DOI: 10.1165/rcmb.2018-0228oc] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Affiliation(s)
- Aurelie Petit
- Department of Respiratory Diseases and Addictology, Hôpital Arnaud de Villeneuve, Centre Hospitalier Universitaire Montpellier, Montpellier, France
| | - Lucie Knabe
- Department of Respiratory Diseases and Addictology, Hôpital Arnaud de Villeneuve, Centre Hospitalier Universitaire Montpellier, Montpellier, France
- Institut National de la Santé et de la Recherche Médicale (INSERM) U1046, Centre National de la Recherche Scientifique (CNRS) Unité Mixte de Recherche (UMR) 9214, University of Montpellier, Montpellier, France
| | - Kamel Khelloufi
- CNRS, Centre Interdisciplinaire de Nanoscience de Marseille UMR 7325, and
| | - Myriam Jory
- UMR 5221 CNRS, Laboratoire Charles Coulomb (L2C), Montpellier, France
| | - Delphine Gras
- Assistance Publique Hôpitaux de Marseille (APHM), Centre de recherche en CardioVasculaire et Nutrition, INSERM U1263 Institut National de la Recherche Agronomique (INRA) 1260, Clinique des Bronches Allergies et Sommeil, Aix Marseille University, Marseille, France
| | - Yann Cabon
- Department of Medical Information, Montpellier University Hospital, Montpellier, France; and
| | - Malcolm Begg
- Refractory Respiratory Inflammation Data Processing Unit, Respiratory TAU, GlaxoSmithKline, Stevenage, United Kingdom
| | - Sylvain Richard
- Institut National de la Santé et de la Recherche Médicale (INSERM) U1046, Centre National de la Recherche Scientifique (CNRS) Unité Mixte de Recherche (UMR) 9214, University of Montpellier, Montpellier, France
| | - Gladys Massiera
- UMR 5221 CNRS, Laboratoire Charles Coulomb (L2C), Montpellier, France
| | - Pascal Chanez
- Assistance Publique Hôpitaux de Marseille (APHM), Centre de recherche en CardioVasculaire et Nutrition, INSERM U1263 Institut National de la Recherche Agronomique (INRA) 1260, Clinique des Bronches Allergies et Sommeil, Aix Marseille University, Marseille, France
| | - Isabelle Vachier
- Department of Respiratory Diseases and Addictology, Hôpital Arnaud de Villeneuve, Centre Hospitalier Universitaire Montpellier, Montpellier, France
| | - Arnaud Bourdin
- Department of Respiratory Diseases and Addictology, Hôpital Arnaud de Villeneuve, Centre Hospitalier Universitaire Montpellier, Montpellier, France
- Institut National de la Santé et de la Recherche Médicale (INSERM) U1046, Centre National de la Recherche Scientifique (CNRS) Unité Mixte de Recherche (UMR) 9214, University of Montpellier, Montpellier, France
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15
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Zhang J, Zhang L, Chen Y, Shi H, Huang X, Wang Y, Wang Y, Wei Y, Xue W, Han J. Effect and mechanism of mGluR6 on the biological function of rat embryonic neural stem cells. Biosci Biotechnol Biochem 2019; 83:1027-1034. [PMID: 30739574 DOI: 10.1080/09168451.2019.1578639] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Here, we investigated the effects and molecular mechanisms of metabotropic glutamate receptor 6 (mGluR6) on rat embryonic neural stem cells (NSCs). Overexpression of mGluR6 significantly promoted the proliferation of NSCs and increased the diameter of neutrospheres after treatment for 24 h, 48 h and 72 h. Overexpression of mGluR6 promoted G1 to S phase transition, with significantly decreased cell ratio in G1/G0 phase but significantly increased cell ratio in S phase. Additionally, mGluR6 overexpression for 48 h decreased the early and late apoptosis significantly. Moreover, overexpression of mGluR6 significantly increased the expression of p-ERK1/2, Cyclin D1 and CDK2, while the expression of p-p38 was significantly decreased. On the contrary, these effects of mGluR6 overexpression were reversed by mGluR6 knockdown. In conclusion, mGluR6 promotes the proliferation of NSCs by activation of ERK1/2-Cyclin D1/CDK2 signaling pathway and inhibits the apoptosis of NSCs by blockage of the p38 MAPK signaling pathway.
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Affiliation(s)
- Jing Zhang
- a Department of Clinical Medicine , Medical College of Yan'an University , Yan'an , P.R. China
| | - Lu Zhang
- b Department of Foreign Languages , Ming De College of Northwestern Polytechnical University , Xi'an , P.R. China
| | - Yani Chen
- a Department of Clinical Medicine , Medical College of Yan'an University , Yan'an , P.R. China
| | - Haiyan Shi
- a Department of Clinical Medicine , Medical College of Yan'an University , Yan'an , P.R. China
| | - Xiaoyong Huang
- a Department of Clinical Medicine , Medical College of Yan'an University , Yan'an , P.R. China
| | - Yanfeng Wang
- a Department of Clinical Medicine , Medical College of Yan'an University , Yan'an , P.R. China
| | - Yu Wang
- a Department of Clinical Medicine , Medical College of Yan'an University , Yan'an , P.R. China
| | - Yameng Wei
- a Department of Clinical Medicine , Medical College of Yan'an University , Yan'an , P.R. China
| | - Wanjuan Xue
- a Department of Clinical Medicine , Medical College of Yan'an University , Yan'an , P.R. China
| | - Jiming Han
- a Department of Clinical Medicine , Medical College of Yan'an University , Yan'an , P.R. China
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16
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Abstract
The skin is the first line of defense against the environment, with the epidermis as the outermost tissue providing much of the barrier function. Given its direct exposure to and encounters with the environment, the epidermis must evolve to provide an optimal barrier for the survival of an organism. Recent advances in genomics have identified a number of genes for the human skin barrier that have undergone evolutionary changes since humans diverged from chimpanzees. Here, we highlight a selection of key and innovative genetic findings for skin barrier evolution in our divergence from our primate ancestors and among modern human populations.
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Affiliation(s)
- Erin A. Brettmann
- Division of Dermatology, Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA
- Center for Pharmacogenomics, Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA
- Center for the Study of Itch, Washington University School of Medicine, St. Louis, MO, USA
| | - Cristina de Guzman Strong
- Division of Dermatology, Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA
- Center for Pharmacogenomics, Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA
- Center for the Study of Itch, Washington University School of Medicine, St. Louis, MO, USA
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17
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Serre C, Busuttil V, Botto JM. Intrinsic and extrinsic regulation of human skin melanogenesis and pigmentation. Int J Cosmet Sci 2018; 40:328-347. [PMID: 29752874 DOI: 10.1111/ics.12466] [Citation(s) in RCA: 135] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Accepted: 05/04/2018] [Indexed: 12/11/2022]
Abstract
In human skin, melanogenesis is a tightly regulated process. Indeed, several extracellular signals are transduced via dedicated signalling pathways and mostly converge to MITF, a transcription factor integrating upstream signalling and regulating downstream genes involved in the various inherent mechanisms modulating melanogenesis. The synthesis of melanin pigments occurs in melanocytes inside melanosomes where melanogenic enzymes (tyrosinase and related proteins) are addressed with the help of specific protein complexes. The melanosomes loaded with melanin are then transferred to keratinocytes. A more elaborate level of melanogenesis regulation comes into play via the action of non-coding RNAs (microRNAs, lncRNAs). Besides this canonical regulation, melanogenesis can also be modulated by other non-specific intrinsic pathways (hormonal environment, inflammation) and by extrinsic factors (solar irradiation such as ultraviolet irradiation, environmental pollution). We developed a bioinformatic interaction network gathering the multiple aspects of melanogenesis and skin pigmentation as a resource to better understand and study skin pigmentation biology.
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Affiliation(s)
- C Serre
- Global Skin Research Center, Ashland, 655, route du Pin Montard, Sophia Antipolis, 06904, France
| | - V Busuttil
- Global Skin Research Center, Ashland, 655, route du Pin Montard, Sophia Antipolis, 06904, France
| | - J-M Botto
- Global Skin Research Center, Ashland, 655, route du Pin Montard, Sophia Antipolis, 06904, France
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18
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Agosto MA, Anastassov IA, Robichaux MA, Wensel TG. A Large Endoplasmic Reticulum-Resident Pool of TRPM1 in Retinal ON-Bipolar Cells. eNeuro 2018; 5:ENEURO.0143-18.2018. [PMID: 30027108 PMCID: PMC6051591 DOI: 10.1523/eneuro.0143-18.2018] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Revised: 05/15/2018] [Accepted: 05/16/2018] [Indexed: 12/22/2022] Open
Abstract
The chemical signal of light onset, a decrease in glutamate release from rod and cone photoreceptors, is processed by a postsynaptic G protein signaling cascade in ON-bipolar cells (BPCs). The metabotropic glutamate receptor mGluR6, along with other cascade elements, is localized synaptically at the BPC dendritic tips. The effector ion channel protein transient receptor potential melastatin-1 (TRPM1), in contrast, is located not only at the dendritic tips but also in BPC bodies and axons. Little is known about the intracellular localization of TRPM1, or its trafficking route to the dendritic tip plasma membrane. Recombinant TRPM1 expressed in mammalian cells colocalized with endoplasmic reticulum (ER) markers, with little or none detected at the plasma membrane. In mouse retina, somatic TRPM1 was similarly intracellular, and not at the plasma membrane. Labeling of ER membranes by expression of a fluorescent marker showed that in BPCs the ER extends into axons and dendrites, but not dendritic tips. In cell bodies, TRPM1 colocalized with the ER, and not with the Golgi apparatus. Fluorescence protease protection (FPP) assays with TRPM1-GFP fusions in heterologous cells revealed that the N and C termini are both accessible to the cytoplasm, consistent with the transmembrane domain topology of related TRP channels. These results indicate that the majority of TRPM1 is present in the ER, from which it can potentially be transported to the dendritic tips as needed for ON light responses. The excess of ER-resident TRPM1 relative to the amount needed at the dendritic tips suggests a potential new function for TRPM1 in the ER.
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Affiliation(s)
- Melina A. Agosto
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030
| | - Ivan A. Anastassov
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030
| | - Michael A. Robichaux
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030
| | - Theodore G. Wensel
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030
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19
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Ballister ER, Rodgers J, Martial F, Lucas RJ. A live cell assay of GPCR coupling allows identification of optogenetic tools for controlling Go and Gi signaling. BMC Biol 2018; 16:10. [PMID: 29338718 PMCID: PMC5771134 DOI: 10.1186/s12915-017-0475-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Accepted: 12/18/2017] [Indexed: 11/10/2022] Open
Abstract
Background Animal opsins are light-sensitive G-protein-coupled receptors (GPCRs) that enable optogenetic control over the major heterotrimeric G-protein signaling pathways in animal cells. As such, opsins have potential applications in both biomedical research and therapy. Selecting the opsin with the best balance of activity and selectivity for a given application requires knowing their ability to couple to a full range of relevant Gα subunits. We present the GsX assay, a set of tools based on chimeric Gs subunits that transduce coupling of opsins to diverse G proteins into increases in cAMP levels, measured with a real-time reporter in living cells. We use this assay to compare coupling to Gi/o/t across a panel of natural and chimeric opsins selected for potential application in gene therapy for retinal degeneration. Results Of the opsins tested, wild-type human rod opsin had the highest activity for chimeric Gs proxies for Gi and Gt (Gsi and Gst) and was matched in Go proxy (Gso) activity only by a human rod opsin/scallop opsin chimera. Rod opsin drove roughly equivalent responses via Gsi, Gso, and Gst, while cone opsins showed much lower activities with Gso than Gsi or Gst, and a human rod opsin/amphioxus opsin chimera demonstrated higher activity with Gso than with Gsi or Gst. We failed to detect activity for opsin chimeras bearing three intracellular fragments of mGluR6, and observed unexpectedly complex response profiles for scallop and amphioxus opsins thought to be specialized for Go. Conclusions These results identify rod opsin as the most potent non-selective Gi/o/t-coupled opsin, long-wave sensitive cone opsin as the best for selectively activating Gi/t over Go, and a rod opsin/amphioxus opsin chimera as the best choice for selectively activating Go over Gi/t. Electronic supplementary material The online version of this article (doi:10.1186/s12915-017-0475-2) contains supplementary material, which is available to authorized users.
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20
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Neto A, Ceol CJ. Melanoma-associated GRM3 variants dysregulate melanosome trafficking and cAMP signaling. Pigment Cell Melanoma Res 2017. [PMID: 28646617 DOI: 10.1111/pcmr.12610] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Large-scale sequencing studies have revealed several genes that are recurrently mutated in melanomas. To annotate the melanoma genome, we have expressed tumor-associated variants of these genes in zebrafish and characterized their effects on melanocyte development and function. Here, we describe expression of tumor-associated variants of the recurrently mutated metabotropic glutamate receptor 3 (GRM3) gene. Unlike wild-type GRM3, tumor-associated GRM3 variants disrupted trafficking of melanosomes, causing their aggregation in the cell body. Melanosomes are trafficked in a cAMP-dependent manner, and drugs that directly or indirectly increased cAMP levels were able to suppress melanosome aggregation in mutant GRM3-expressing melanocytes. Our data show that oncogenic GRM3 variants dysregulate cAMP signaling, a heretofore unknown role for these oncogenes. cAMP signaling has been implicated in melanoma progression and drug resistance, and our data show that oncogenic properties of GRM3 could be mediated, at least in part, by alterations in cAMP signaling.
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Affiliation(s)
- Ana Neto
- Program in Molecular Medicine and Department of Molecular Cell and Cancer Biology, University of Massachusetts Medical School, Worcester, MA, USA
| | - Craig J Ceol
- Program in Molecular Medicine and Department of Molecular Cell and Cancer Biology, University of Massachusetts Medical School, Worcester, MA, USA
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21
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Quallo T, Alkhatib O, Gentry C, Andersson DA, Bevan S. G protein βγ subunits inhibit TRPM3 ion channels in sensory neurons. eLife 2017; 6. [PMID: 28826490 PMCID: PMC5593501 DOI: 10.7554/elife.26138] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Accepted: 07/24/2017] [Indexed: 02/07/2023] Open
Abstract
Transient receptor potential (TRP) ion channels in peripheral sensory neurons are functionally regulated by hydrolysis of the phosphoinositide PI(4,5)P2 and changes in the level of protein kinase mediated phosphorylation following activation of various G protein coupled receptors. We now show that the activity of TRPM3 expressed in mouse dorsal root ganglion (DRG) neurons is inhibited by agonists of the Gi-coupled µ opioid, GABA-B and NPY receptors. These agonist effects are mediated by direct inhibition of TRPM3 by Gβγ subunits, rather than by a canonical cAMP mediated mechanism. The activity of TRPM3 in DRG neurons is also negatively modulated by tonic, constitutive GPCR activity as TRPM3 responses can be potentiated by GPCR inverse agonists. GPCR regulation of TRPM3 is also seen in vivo where Gi/o GPCRs agonists inhibited and inverse agonists potentiated TRPM3 mediated nociceptive behavioural responses. DOI:http://dx.doi.org/10.7554/eLife.26138.001 TRPM3 belongs to a family of channel proteins that allow sodium and calcium ions to enter cells by forming pores in cell membranes. TRPM3 is found on the cell membranes of nerve cells; when ions flow into the nerves through the TRPM3 pores it triggers an electrical impulse. TRPM3 is responsible for helping us to detect heat, and mice without this protein find it difficult to sense painfully hot temperatures. Mice lacking TRPM3 also respond to other kinds of pain differently. Normally, a mouse with an injured paw becomes more sensitive to warm and hot temperatures, but this does not happen in mice that do not have TRPM3. When activated, other proteins called G-protein coupled receptors (or GPCRs for short) can make some members of this family of channel proteins more or less likely to open their pore. This in turn increases or decreases the flow of ions through the pore, respectively. Yet it was not clear if GPCRs also affect TRPM3 channels on the membranes of nerve cells. Quallo et al. have now discovered that “switching on” different GPCR proteins in sensory nerve cells from mice greatly reduces the flow of calcium ions though TRPM3 channels. The experiments made use of two pain-killing drugs, namely morphine and baclofen, and a molecule called neuropeptide Y to activate different GPCRs. GPCRs interact with a group of small proteins called G-proteins that, when activated by the receptor, split into two subunits, known as the α subunit and the βγ subunit. Once detached these subunits are free to act as messengers and interact with other proteins in the cell membrane. Quallo et al. found that TRPM3 is one of a small group of proteins that interact with the βγ subunits of the G-protein, which can explain how “switching on” GPCRs reduces the activity of TRPM3. Two independent studies by Dembla, Behrendt et al. and Badheka, Yudin et al. also report similar findings. There is currently a need to find more effective treatments for people suffering from long-term pain conditions and it has become clear that TRPM3 channels are involved in sensing both pain and temperature. These new findings show that drugs already used in the treatment of pain can dramatically change how TRPM3 works. These results might help scientists to find drugs that work in a similar way to dial down the activity of TRPM3 and to combat pain. Though first it will be important to confirm these new findings in human nerve cells. DOI:http://dx.doi.org/10.7554/eLife.26138.002
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Affiliation(s)
- Talisia Quallo
- Wolfson Centre for Age-Related Diseases, King's College London, London, United Kingdom
| | - Omar Alkhatib
- Wolfson Centre for Age-Related Diseases, King's College London, London, United Kingdom
| | - Clive Gentry
- Wolfson Centre for Age-Related Diseases, King's College London, London, United Kingdom
| | - David A Andersson
- Wolfson Centre for Age-Related Diseases, King's College London, London, United Kingdom
| | - Stuart Bevan
- Wolfson Centre for Age-Related Diseases, King's College London, London, United Kingdom
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22
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Duvoisin RM, Haley TL, Ren G, Strycharska-Orczyk I, Bonaparte JP, Morgans CW. Autoantibodies in Melanoma-Associated Retinopathy Recognize an Epitope Conserved Between TRPM1 and TRPM3. Invest Ophthalmol Vis Sci 2017; 58:2732-2738. [PMID: 28549093 PMCID: PMC5455167 DOI: 10.1167/iovs.17-21443] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Purpose Melanoma-associated retinopathy (MAR) is a paraneoplastic syndrome associated with malignant melanoma and the presence of anti-retinal autoantibodies, including autoantibodies against transient receptor potential melanopsin 1 (TRPM1), a cation channel expressed by both melanocytes and retinal bipolar cells. The goal of this study was to further map the antigenic epitope. Methods Patient sera were tested by immunofluorescence and Western blotting on HEK293 cells transfected with enhanced green fluorescent protein (EGFP)-TRPM1 fusion constructs and mouse retina sections. Results The epitope recognized by MAR patient sera was mapped to a region encoded by exons 9 and 10 of the human TRPM1 gene. This region of TRPM1 is highly conserved with TRPM3, and indeed MAR sera were found to cross-react with TRPM3, a closely related channel expressed in the retinal pigment epithelium (RPE). Conclusions These results indicate that TRPM1 autoantibodies in MAR patient sera recognize a short, intracellular segment of TRPM1. Cross-reactivity with TRPM3 in the RPE may account for other visual symptoms that are experienced by some MAR patients such as retinal and RPE detachments. We propose that TRPM1 autoantibodies are generated in response to abnormal TRPM1 polypeptides encoded by an alternate mRNA splice variant expressed by malignant melanocytes.
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Affiliation(s)
- Robert M Duvoisin
- Department of Physiology and Pharmacology, Oregon Health & Science University, Portland, Oregon, United States
| | - Tammie L Haley
- Department of Physiology and Pharmacology, Oregon Health & Science University, Portland, Oregon, United States
| | - Gaoying Ren
- Department of Physiology and Pharmacology, Oregon Health & Science University, Portland, Oregon, United States
| | - Iwona Strycharska-Orczyk
- Department of Physiology and Pharmacology, Oregon Health & Science University, Portland, Oregon, United States
| | - James P Bonaparte
- Department of Physiology and Pharmacology, Oregon Health & Science University, Portland, Oregon, United States
| | - Catherine W Morgans
- Department of Physiology and Pharmacology, Oregon Health & Science University, Portland, Oregon, United States
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23
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TRP Channels in Skin Biology and Pathophysiology. Pharmaceuticals (Basel) 2016; 9:ph9040077. [PMID: 27983625 PMCID: PMC5198052 DOI: 10.3390/ph9040077] [Citation(s) in RCA: 334] [Impact Index Per Article: 41.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Revised: 12/08/2016] [Accepted: 12/09/2016] [Indexed: 11/17/2022] Open
Abstract
Ion channels of the Transient Receptor Potential (TRP) family mediate the influx of monovalent and/or divalent cations into cells in response to a host of chemical or physical stimuli. In the skin, TRP channels are expressed in many cell types, including keratinocytes, sensory neurons, melanocytes, and immune/inflammatory cells. Within these diverse cell types, TRP channels participate in physiological processes ranging from sensation to skin homeostasis. In addition, there is a growing body of evidence implicating abnormal TRP channel function, as a product of excessive or deficient channel activity, in pathological skin conditions such as chronic pain and itch, dermatitis, vitiligo, alopecia, wound healing, skin carcinogenesis, and skin barrier compromise. These diverse functions, coupled with the fact that many TRP channels possess pharmacologically accessible sites, make this family of proteins appealing therapeutic targets for skin disorders.
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24
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Zheng S, Sun Z, Ni J, Li Z, Sha Y, Zhang T, Qiao S, Zhao G, Song Z. mGluR6 regulates keratinocyte phagocytosis by modulating CaM KII/ERK/MLC signalling pathway. Exp Dermatol 2016; 25:909-911. [PMID: 27246800 DOI: 10.1111/exd.13096] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/24/2016] [Indexed: 12/17/2022]
Affiliation(s)
- Siwen Zheng
- Department of Dermatology, 1st Affiliated Hospital of Dalian Medical University, Dalian City, Liaoning Province, China
| | - Zhe Sun
- Department of Dermatology, 1st Affiliated Hospital of Dalian Medical University, Dalian City, Liaoning Province, China
| | - Jing Ni
- Department of Dermatology, 1st Affiliated Hospital of Dalian Medical University, Dalian City, Liaoning Province, China
| | - Zhen Li
- Department of Dermatology, 1st Affiliated Hospital of Dalian Medical University, Dalian City, Liaoning Province, China
| | - Yang Sha
- Department of Dermatology, 1st Affiliated Hospital of Dalian Medical University, Dalian City, Liaoning Province, China
| | - Ting Zhang
- Department of Dermatology, 1st Affiliated Hospital of Dalian Medical University, Dalian City, Liaoning Province, China
| | - Song Qiao
- Department of Dermatology, 1st Affiliated Hospital of Dalian Medical University, Dalian City, Liaoning Province, China
| | - Guangming Zhao
- Department of Dermatology, 1st Affiliated Hospital of Dalian Medical University, Dalian City, Liaoning Province, China
| | - Zhiqi Song
- Department of Dermatology, 1st Affiliated Hospital of Dalian Medical University, Dalian City, Liaoning Province, China.
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25
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The TRPM1 channel in ON-bipolar cells is gated by both the α and the βγ subunits of the G-protein Go. Sci Rep 2016; 6:20940. [PMID: 26883481 PMCID: PMC4756708 DOI: 10.1038/srep20940] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Accepted: 12/16/2015] [Indexed: 12/25/2022] Open
Abstract
Transmission from photoreceptors to ON bipolar cells in mammalian retina is mediated by a sign-inverting cascade. Upon binding glutamate, the metabotropic glutamate receptor mGluR6 activates the heterotrimeric G-protein Gαoβ3γ13, and this leads to closure of the TRPM1 channel (melastatin). TRPM1 is thought to be constitutively open, but the mechanism that leads to its closure is unclear. We investigated this question in mouse rod bipolar cells by dialyzing reagents that modify the activity of either Gαo or Gβγ and then observing their effects on the basal holding current. After opening the TRPM1 channels with light, a constitutively active mutant of Gαo closed the channel, but wild-type Gαo did not. After closing the channels by dark adaptation, phosducin or inactive Gαo (both sequester Gβγ) opened the channel while the active mutant of Gαo did not. Co-immunoprecipitation showed that TRPM1 interacts with Gβ3 and with the active and inactive forms of Gαo. Furthermore, bioluminescent energy transfer assays indicated that while Gαo interacts with both the N- and the C- termini of TRPM1, Gβγ interacts only with the N-terminus. Our physiological and biochemical results suggest that both Gαo and Gβγ bind TRPM1 channels and cooperate to close them.
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26
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Reinach PS, Mergler S, Okada Y, Saika S. Ocular transient receptor potential channel function in health and disease. BMC Ophthalmol 2015; 15 Suppl 1:153. [PMID: 26818117 PMCID: PMC4895786 DOI: 10.1186/s12886-015-0135-7] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Transient receptor potential (TRP) channels sense and transduce environmental stimuli into Ca(2+) transients that in turn induce responses essential for cell function and adaptation. These non-selective channels with variable Ca(2+) selectivity are grouped into seven different subfamilies containing 28 subtypes based on differences in amino acid sequence homology. Many of these subtypes are expressed in the eye on both neuronal and non-neuronal cells where they affect a host of stress-induced regulatory responses essential for normal vision maintenance. This article reviews our current knowledge about the expression, function and regulation of TRPs in different eye tissues. We also describe how under certain conditions TRP activation can induce responses that are maladaptive to ocular function. Furthermore, the possibility of an association between TRP mutations and disease is considered. These findings contribute to evidence suggesting that drug targeting TRP channels may be of therapeutic benefit in a clinical setting. We point out issues that must be more extensively addressed before it will be possible to decide with certainty that this is a realistic endeavor. Another possible upshot of future studies is that disease process progression can be better evaluated by profiling changes in tissue specific functional TRP subtype activity as well as their gene and protein expression.
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Affiliation(s)
- Peter S Reinach
- Department of Ophthalmology and Optometry, Wenzhou Medical University, 270 Xuejuan Road, Wenzhou, Zhejiang, 325027, P. R. China.
| | - Stefan Mergler
- Department of Ophthalmology, Charité-University Medicine Berlin, Campus Virchow-Clinic, Augustenburger Platz 1, 13353, Berlin, Germany.
| | - Yuka Okada
- Department of Ophthalmology, Wakayama Medical University School of Medicine, Wakayama, Japan.
| | - Shizuya Saika
- Department of Ophthalmology, Wakayama Medical University School of Medicine, Wakayama, Japan.
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27
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Schneider FM, Mohr F, Behrendt M, Oberwinkler J. Properties and functions of TRPM1 channels in the dendritic tips of retinal ON-bipolar cells. Eur J Cell Biol 2015; 94:420-7. [PMID: 26111660 DOI: 10.1016/j.ejcb.2015.06.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
An increase in light intensity induces a depolarization in retinal ON-bipolar cells via a reduced glutamate release from presynaptic photoreceptor cells. The underlying transduction cascade in the dendritic tips of ON-bipolar cells involves mGluR6 glutamate receptors signaling to TRPM1 proteins that are an indispensable part of the transduction channel. Several other proteins are recognized to participate in the transduction machinery. Deficiency in many of these leads to congenital stationary night blindness, because rod bipolar cells, a subgroup of ON-bipolar cells, constitute the main route for sensory information under scotopic conditions. Here, we review the current knowledge about TRPM1 ion channels and how their activity is regulated within the postsynaptic compartment of ON-bipolar cells. The functional properties of TRPM1 channels in the dendritic compartment are not well understood as they differ substantially from those of recombinant TRPM1 channels. Critical evaluation of possible explanations of these discrepancies indicates that some key components of this transduction pathway might still not be known. The continued exploration of this pathway will yield further clinically useful insights.
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Affiliation(s)
- Franziska M Schneider
- Institut für Physiologie und Pathophysiologie, Philipps-Universität Marburg, Deutschhausstr. 1-2, D-35037 Marburg, Germany
| | - Florian Mohr
- Institut für Physiologie und Pathophysiologie, Philipps-Universität Marburg, Deutschhausstr. 1-2, D-35037 Marburg, Germany
| | - Marc Behrendt
- Institut für Physiologie und Pathophysiologie, Philipps-Universität Marburg, Deutschhausstr. 1-2, D-35037 Marburg, Germany
| | - Johannes Oberwinkler
- Institut für Physiologie und Pathophysiologie, Philipps-Universität Marburg, Deutschhausstr. 1-2, D-35037 Marburg, Germany.
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28
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Nilius B, Szallasi A. Transient Receptor Potential Channels as Drug Targets: From the Science of Basic Research to the Art of Medicine. Pharmacol Rev 2014; 66:676-814. [DOI: 10.1124/pr.113.008268] [Citation(s) in RCA: 348] [Impact Index Per Article: 34.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
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Ueno S, Ito Y, Maruko R, Kondo M, Terasaki H. Choroidal atrophy in a patient with paraneoplastic retinopathy and anti-TRPM1 antibody. Clin Ophthalmol 2014; 8:369-73. [PMID: 24523577 PMCID: PMC3921079 DOI: 10.2147/opth.s55124] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The purpose of this paper is to report choroidal atrophy in a patient with cancer-associated retinopathy who had autoantibodies against the transient receptor potential cation channel, subfamily M, member 1 (TRPM1). A 69-year-old man visited our clinic in July 2010 with complaints of blurred vision and night blindness in both eyes. The full-field electroretinograms were negative type, indicating ON bipolar cell dysfunction. General physical examination revealed small cell carcinoma of the lung, and Western blot of the patient’s serum showed autoantibodies against TRPM1. We diagnosed this patient with cancer-associated retinopathy and retinal ON bipolar dysfunction due to anti-TRPM1 autoantibody. We followed him for more than 2 years from the initial visit and his symptoms have not changed. However, consistent with the choroidal hypopigmentation of the fundus, spectral domain optical coherence tomography showed a decrease in choroidal thickness of about one third over a 2-year follow-up period. We suggest that this case of gradually progressive choroidal atrophy was caused by the autoantibody against TRPM1 directly, because TRPM1 is expressed not only on ON bipolar cells but also on melanocytes. These findings indicate that we should be aware of choroidal thickness in patients with paraneoplastic retinopathy who have retinal ON bipolar dysfunction with the anti-TRPM1 antibody.
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Affiliation(s)
- Shinji Ueno
- Department of Ophthalmology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Yasuki Ito
- Department of Ophthalmology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Ruka Maruko
- Department of Ophthalmology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Mineo Kondo
- Department of Ophthalmology, Mie University Graduate School of Medicine, Tsu, Japan
| | - Hiroko Terasaki
- Department of Ophthalmology, Nagoya University Graduate School of Medicine, Nagoya, Japan
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Abstract
The transient receptor potential (TRP) channels play a wide variety of essential roles in the sensory systems of various species, both invertebrates and vertebrates. The TRP channel was first identified as a molecule required for proper light response in Drosophila melanogaster. We and another group recently revealed that TRPM1, the founding member of the melanoma-related transient receptor potential (TRPM) subfamily, is required for the photoresponse in mouse retinal ON-bipolar cells. We further demonstrated that Trpm1 is a component of the transduction cation channel negatively regulated by the metabotropic glutamate receptor 6 (mGulR6) cascade in ON-bipolar cells through a reconstitution experiment using CHO cells expressing Trpm1, mGluR6, and Goα. Furthermore, human TRPM1 mutations are associated with congenital stationary night blindness (CSNB), whose patients lack rod function and suffer from night blindness starting in early childhood. In addition to the function of transduction cation channel, TRPM1 is one of the retinal autoantigens in some paraneoplastic retinopathy (PR) associated with retinal ON-bipolar cell dysfunction. In this chapter, we describe physiological functions of the TRPM1 channel and its underlying biochemical mechanisms in retinal ON-bipolar cells in association with CSNB and PR.
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Affiliation(s)
- Shoichi Irie
- Laboratory for Molecular and Developmental Biology, Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
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31
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Saul S, Stanisz H, Backes CS, Schwarz EC, Hoth M. How ORAI and TRP channels interfere with each other: interaction models and examples from the immune system and the skin. Eur J Pharmacol 2013; 739:49-59. [PMID: 24291108 DOI: 10.1016/j.ejphar.2013.10.071] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2013] [Revised: 10/08/2013] [Accepted: 10/17/2013] [Indexed: 11/16/2022]
Abstract
Four types of Ca(2+) selective ion channels are known, ten voltage gated Ca(2+) (CaV) channels, four CatSper channels, three store operated CRAC channels (ORAI channels) and at least two members of the TRPV subfamily (TRPV5, TRPV6). Some of the other TRP channels also show some Ca(2+) selectivity like certain splice variants of TRPM3. In addition to Ca(2+) selective channels, various cation channels play an important role for Ca(2+) entry and furthermore, they may also regulate Ca(2+) entry through other channels by modulating the membrane potential or other means as outlined in this review. Of the different types of cation channels, TRP channels form one of the most prominent families of non-selective cation channels with functional relevance in electrically non-excitable and electrically excitable cell types. Among these, the seven channels of the TRPC subfamily are rather non-selective with very modest Ca(2+) selectivity, whereas in the other subfamilies, cation selectivity ranges from monovalent selectivity (i.e. TRPM4, TRPM5) to divalent selectivity (i.e. TRPM6, TRPM7) or Ca(2+) selectivity (i.e. TRPV5, TRPV6). Rather than discussing the heavily reviewed individual functions of ORAI or TRP channels, we summarize data and present models how TRP and ORAI may functionally interact to guide cellular functions. We focus on T lymphocytes representing a more ORAI-dominated tissue and skin as model system in which both ORAI and TRP channel have been reported to control relevant functions. We present several interaction models how ORAI and TRP may interfere with each other's function.
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Affiliation(s)
- Stephanie Saul
- Department of Biophysics, School of Medicine, Saarland University, Homburg, Germany
| | - Hedwig Stanisz
- Department of Dermatology, School of Medicine, Saarland University, Homburg, Germany
| | - Christian S Backes
- Department of Biophysics, School of Medicine, Saarland University, Homburg, Germany
| | - Eva C Schwarz
- Department of Biophysics, School of Medicine, Saarland University, Homburg, Germany
| | - Markus Hoth
- Department of Biophysics, School of Medicine, Saarland University, Homburg, Germany.
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Schmunk G, Gargus JJ. Channelopathy pathogenesis in autism spectrum disorders. Front Genet 2013; 4:222. [PMID: 24204377 PMCID: PMC3817418 DOI: 10.3389/fgene.2013.00222] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2013] [Accepted: 10/09/2013] [Indexed: 01/12/2023] Open
Abstract
Autism spectrum disorder (ASD) is a syndrome that affects normal brain development and is characterized by impaired social interaction as well as verbal and non-verbal communication and by repetitive, stereotypic behavior. ASD is a complex disorder arising from a combination of multiple genetic and environmental factors that are independent from racial, ethnic and socioeconomical status. The high heritability of ASD suggests a strong genetic basis for the disorder. Furthermore, a mounting body of evidence implies a role of various ion channel gene defects (channelopathies) in the pathogenesis of autism. Indeed, recent genome-wide association, and whole exome- and whole-genome resequencing studies linked polymorphisms and rare variants in calcium, sodium and potassium channels and their subunits with susceptibility to ASD, much as they do with bipolar disorder, schizophrenia and other neuropsychiatric disorders. Moreover, animal models with these genetic variations recapitulate endophenotypes considered to be correlates of autistic behavior seen in patients. An ion flux across the membrane regulates a variety of cell functions, from generation of action potentials to gene expression and cell morphology, thus it is not surprising that channelopathies have profound effects on brain functions. In the present work, we summarize existing evidence for the role of ion channel gene defects in the pathogenesis of autism with a focus on calcium signaling and its downstream effects.
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Affiliation(s)
- Galina Schmunk
- Department of Physiology and Biophysics, University of California Irvine, CA, USA ; UCI Center for Autism Research and Treatment, School of Medicine, University of California Irvine, CA, USA
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Bellone RR, Holl H, Setaluri V, Devi S, Maddodi N, Archer S, Sandmeyer L, Ludwig A, Foerster D, Pruvost M, Reissmann M, Bortfeldt R, Adelson DL, Lim SL, Nelson J, Haase B, Engensteiner M, Leeb T, Forsyth G, Mienaltowski MJ, Mahadevan P, Hofreiter M, Paijmans JLA, Gonzalez-Fortes G, Grahn B, Brooks SA. Evidence for a retroviral insertion in TRPM1 as the cause of congenital stationary night blindness and leopard complex spotting in the horse. PLoS One 2013; 8:e78280. [PMID: 24167615 PMCID: PMC3805535 DOI: 10.1371/journal.pone.0078280] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Accepted: 09/10/2013] [Indexed: 12/21/2022] Open
Abstract
Leopard complex spotting is a group of white spotting patterns in horses caused by an incompletely dominant gene (LP) where homozygotes (LP/LP) are also affected with congenital stationary night blindness. Previous studies implicated Transient Receptor Potential Cation Channel, Subfamily M, Member 1 (TRPM1) as the best candidate gene for both CSNB and LP. RNA-Seq data pinpointed a 1378 bp insertion in intron 1 of TRPM1 as the potential cause. This insertion, a long terminal repeat (LTR) of an endogenous retrovirus, was completely associated with LP, testing 511 horses (χ2=1022.00, p<<0.0005), and CSNB, testing 43 horses (χ2=43, p<<0.0005). The LTR was shown to disrupt TRPM1 transcription by premature poly-adenylation. Furthermore, while deleterious transposable element insertions should be quickly selected against the identification of this insertion in three ancient DNA samples suggests it has been maintained in the horse gene pool for at least 17,000 years. This study represents the first description of an LTR insertion being associated with both a pigmentation phenotype and an eye disorder.
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Affiliation(s)
- Rebecca R. Bellone
- Department of Biology, University of Tampa, Tampa, Florida, United States of America
- * E-mail:
| | - Heather Holl
- Department of Animal Science, Cornell University, Ithaca, New York, United States of America
| | - Vijayasaradhi Setaluri
- Department of Dermatology, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin, United States of America
| | - Sulochana Devi
- Department of Dermatology, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin, United States of America
| | - Nityanand Maddodi
- Department of Dermatology, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin, United States of America
| | | | - Lynne Sandmeyer
- Department of Small Animal Clinical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Arne Ludwig
- Department of Evolutionary Genetics, Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany
| | - Daniel Foerster
- Department of Evolutionary Genetics, Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany
| | - Melanie Pruvost
- Department of Evolutionary Genetics, Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany
- Epigenomic and Palaeogenomic Group, Institut Jacques Monod, Paris, France
| | - Monika Reissmann
- Department of Breeding Biology and Molecular Genetics, Humboldt University Berlin, Berlin, Germany
| | - Ralf Bortfeldt
- Department of Breeding Biology and Molecular Genetics, Humboldt University Berlin, Berlin, Germany
| | - David L. Adelson
- School of Molecular and Biomedical Science, the University of Adelaide, South Australia, Australia
| | - Sim Lin Lim
- School of Molecular and Biomedical Science, the University of Adelaide, South Australia, Australia
| | - Janelle Nelson
- Department of Biology, University of Tampa, Tampa, Florida, United States of America
| | - Bianca Haase
- Faculty of Veterinary Science, University of Sydney, Sydney, New South Wales, Australia
| | | | - Tosso Leeb
- Institute of Genetics, University of Bern, Bern, Switzerland
| | - George Forsyth
- Department of Veterinary Biomedical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Michael J. Mienaltowski
- Department of Molecular Pharmacology & Physiology, College of Medicine, University of South Florida, Tampa, Florida, United States of America
| | - Padmanabhan Mahadevan
- Department of Biology, University of Tampa, Tampa, Florida, United States of America
| | | | | | | | - Bruce Grahn
- Department of Small Animal Clinical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Samantha A. Brooks
- Department of Animal Science, Cornell University, Ithaca, New York, United States of America
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Gerka-Stuyt J, Au A, Peachey NS, Alagramam KN. Transient receptor potential melastatin 1: a hair cell transduction channel candidate. PLoS One 2013; 8:e77213. [PMID: 24146970 PMCID: PMC3795643 DOI: 10.1371/journal.pone.0077213] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2013] [Accepted: 09/03/2013] [Indexed: 11/29/2022] Open
Abstract
Sound and head movements are perceived through sensory hair cells in the inner ear. Mounting evidence indicates that this process is initiated by the opening of mechanically sensitive calcium-permeable channels, also referred to as the mechanoelectrical transducer (MET) channels, reported to be around the tips of all but the tallest stereocilia. However, the identity of MET channel remains elusive. Literature suggests that the MET channel is a non-selective cation channel with a high Ca2+ permeability and ∼100 picosiemens conductance. These characteristics make members of the transient receptor potential (TRP) superfamily likely candidates for this role. One of these candidates is the transient receptor potential melastatin 1 protein (TRPM1), which is expressed in various cells types within the cochlea of the mouse including the hair cells. Recent studies demonstrate that mutations in the TRPM1 gene underlie the inherited retinal disease complete congenital stationary night blindness in humans and depolarizing bipolar cell dysfunction in the mouse retina, but auditory function was not assessed. Here we investigate the role of Trpm1 in hearing and as a possible hair cell MET channel using mice homozygous for the null allele of Trpm1 (Trpm1−/−) or a missense mutation in the pore domain of TRPM1 (Trpm1tvrm27/tvrm27). Hearing thresholds were evaluated in adult (4–5 months old) mice with auditory-evoked brain stem responses. Our data shows no statistically significant difference in hearing thresholds in Trpm1−/− or Trpm1tvrm27/tvrm27 mutants compared to littermate controls. Further, none of the mutant mice showed any sign of balance disorder, such as head bobbing or circling. These data suggest that TRPM1 is not essential for development of hearing or balance and it is unlikely that TRPM1 is a component of the hair cell MET channel.
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Affiliation(s)
- John Gerka-Stuyt
- Otolaryngology Head and Neck Surgery, University Hospitals Case Medical Center, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Adrian Au
- Otolaryngology Head and Neck Surgery, University Hospitals Case Medical Center, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Neal S. Peachey
- Research Service, Louis Stokes Cleveland VA Medical Center, Cleveland, Ohio, United States of America
- Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, United States of America
- Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Kumar N. Alagramam
- Otolaryngology Head and Neck Surgery, University Hospitals Case Medical Center, Case Western Reserve University, Cleveland, Ohio, United States of America
- * E-mail:
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