1
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Xu J, Zhao C, Kang Y. The Formation and Renewal of Photoreceptor Outer Segments. Cells 2024; 13:1357. [PMID: 39195247 DOI: 10.3390/cells13161357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2024] [Revised: 08/12/2024] [Accepted: 08/13/2024] [Indexed: 08/29/2024] Open
Abstract
The visual system is essential for humans to perceive the environment. In the retina, rod and cone photoreceptor neurons are the initial sites where vision forms. The apical region of both cone and rod photoreceptors contains a light-sensing organelle known as the outer segment (OS), which houses tens of thousands of light-sensitive opsins. The OSs of photoreceptors are not static; they require rhythmic renewal to maintain normal physiological functions. Disruptions in OS renewal can lead to various genetic disorders, such as retinitis pigmentosa (RP). Understanding the patterns and molecular mechanisms of photoreceptor OS renewal remains one of the most intriguing topics in visual biology. This review aims to elucidate the structure of photoreceptor OSs, the molecular mechanisms underlying photoreceptor OS renewal, and the retinal diseases resulting from defects in this renewal process. Additionally, we will explore retinal diseases related to photoreceptor OS renewal and potential therapeutic strategies, concluding with a discussion on future research directions for OS renewal.
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Affiliation(s)
- Jingjin Xu
- College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China
- MoE Key Laboratory of Evolution and Marine Biodiversity, Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao 266003, China
| | - Chengtian Zhao
- College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China
- MoE Key Laboratory of Evolution and Marine Biodiversity, Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao 266003, China
| | - Yunsi Kang
- College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China
- MoE Key Laboratory of Evolution and Marine Biodiversity, Institute of Evolution and Marine Biodiversity, Ocean University of China, Qingdao 266003, China
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2
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Lin JL, Chang Y, Tewari D, Cowgill J, Chanda B. Mapping the contribution of the C-linker domain to gating polarity in CNBD channels. Biophys J 2024; 123:2176-2184. [PMID: 38678368 PMCID: PMC11309966 DOI: 10.1016/j.bpj.2024.04.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Revised: 03/23/2024] [Accepted: 04/22/2024] [Indexed: 04/29/2024] Open
Abstract
Ion channels of the cyclic nucleotide-binding domain (CNBD) family play a crucial role in the regulation of key biological processes, such as photoreception and pacemaking activity in the heart. These channels exhibit high sequence and structural similarity but differ greatly in their functional responses to membrane potential. The CNBD family includes hyperpolarization-activated ion channels and depolarization-activated ether-à-go-go channels. Structural and functional studies show that the differences in the coupling interface between these two subfamilies' voltage-sensing domain and pore domain may underlie their differential response to membrane polarity. However, other structural components may also contribute to defining the polarity differences in activation. Here, we focus on the role of the C-terminal domain, which interacts with elements in both the pore and voltage-sensing domains. By generating a series of chimeras involving the C-terminal domain derived from distant members of the CNBD family, we find that the nature of the C-termini profoundly influences the gating polarity of these ion channels. Scanning mutagenesis of the C-linker region, a helix-turn-helix motif connecting the pore helix to the CNBD, reveals that residues at the intersubunit interface between the C-linkers are crucial for hyperpolarization-dependent activation. These findings highlight the unique and unexpected role of the intersubunit interface of the C-linker region in regulating the gating polarity of voltage-gated ion channels.
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Affiliation(s)
- Jenna L Lin
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri; Center for the Investigation of Membrane Excitability Diseases, Washington University School of Medicine, St. Louis, Missouri; Graduate Program in Biochemistry, Biophysics, & Structural Biology, Washington University School of Medicine, St. Louis, Missouri
| | - Yongchang Chang
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri; Center for the Investigation of Membrane Excitability Diseases, Washington University School of Medicine, St. Louis, Missouri
| | - Debanjan Tewari
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri; Center for the Investigation of Membrane Excitability Diseases, Washington University School of Medicine, St. Louis, Missouri
| | - John Cowgill
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri; Center for the Investigation of Membrane Excitability Diseases, Washington University School of Medicine, St. Louis, Missouri
| | - Baron Chanda
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri; Center for the Investigation of Membrane Excitability Diseases, Washington University School of Medicine, St. Louis, Missouri.
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3
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Bastola T, Perkins GA, Huu VAN, Ju S, Kim KY, Shen Z, Skowronska-Krawczyk D, Weinreb RN, Ju WK. Administration of Bicarbonate Protects Mitochondria, Rescues Retinal Ganglion Cells, and Ameliorates Visual Dysfunction Caused by Oxidative Stress. Antioxidants (Basel) 2024; 13:743. [PMID: 38929182 PMCID: PMC11200884 DOI: 10.3390/antiox13060743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2024] [Revised: 06/11/2024] [Accepted: 06/17/2024] [Indexed: 06/28/2024] Open
Abstract
Oxidative stress is a key factor causing mitochondrial dysfunction and retinal ganglion cell (RGC) death in glaucomatous neurodegeneration. The cyclic adenosine monophosphate (cAMP)/protein kinase A (PKA) signaling pathway is involved in mitochondrial protection, promoting RGC survival. Soluble adenylyl cyclase (sAC) is a key regulator of the cyclic adenosine monophosphate (cAMP)/protein kinase A (PKA) signaling pathway, which is known to protect mitochondria and promote RGC survival. However, the precise molecular mechanisms connecting the sAC-mediated signaling pathway with mitochondrial protection in RGCs against oxidative stress are not well characterized. Here, we demonstrate that sAC plays a critical role in protecting RGC mitochondria from oxidative stress. Using mouse models of oxidative stress induced by ischemic injury and paraquat administration, we found that administration of bicarbonate, as an activator of sAC, protected RGCs, blocked AMP-activated protein kinase activation, inhibited glial activation, and improved visual function. Moreover, we found that this is the result of preserving mitochondrial dynamics (fusion and fission), promoting mitochondrial bioenergetics and biogenesis, and preventing metabolic stress and apoptotic cell death. Notably, the administration of bicarbonate ameliorated mitochondrial dysfunction in RGCs by enhancing mitochondrial biogenesis, preserving mitochondrial structure, and increasing ATP production in oxidatively stressed RGCs. These findings suggest that activating sAC enhances the mitochondrial structure and function in RGCs to counter oxidative stress, consequently promoting RGC protection. We propose that modulation of the sAC-mediated signaling pathway has therapeutic potential acting on RGC mitochondria for treating glaucoma and other retinal diseases.
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Affiliation(s)
- Tonking Bastola
- Hamilton Glaucoma Center and Shiley Eye Institute, Viterbi Family Department of Ophthalmology, University of California San Diego, La Jolla, CA 92093, USA; (T.B.); (V.A.N.H.); (Z.S.); (R.N.W.)
| | - Guy A. Perkins
- National Center for Microscopy and Imaging Research, Department of Neurosciences, University of California San Diego, La Jolla, CA 92093, USA (S.J.); (K.-Y.K.)
| | - Viet Anh Nguyen Huu
- Hamilton Glaucoma Center and Shiley Eye Institute, Viterbi Family Department of Ophthalmology, University of California San Diego, La Jolla, CA 92093, USA; (T.B.); (V.A.N.H.); (Z.S.); (R.N.W.)
| | - Saeyeon Ju
- National Center for Microscopy and Imaging Research, Department of Neurosciences, University of California San Diego, La Jolla, CA 92093, USA (S.J.); (K.-Y.K.)
| | - Keun-Young Kim
- National Center for Microscopy and Imaging Research, Department of Neurosciences, University of California San Diego, La Jolla, CA 92093, USA (S.J.); (K.-Y.K.)
| | - Ziyao Shen
- Hamilton Glaucoma Center and Shiley Eye Institute, Viterbi Family Department of Ophthalmology, University of California San Diego, La Jolla, CA 92093, USA; (T.B.); (V.A.N.H.); (Z.S.); (R.N.W.)
| | - Dorota Skowronska-Krawczyk
- Center for Translational Vision Research, Department of Physiology, Biophysics & Ophthalmology, University of California Irvine, Irvine, CA 92697, USA;
| | - Robert N. Weinreb
- Hamilton Glaucoma Center and Shiley Eye Institute, Viterbi Family Department of Ophthalmology, University of California San Diego, La Jolla, CA 92093, USA; (T.B.); (V.A.N.H.); (Z.S.); (R.N.W.)
| | - Won-Kyu Ju
- Hamilton Glaucoma Center and Shiley Eye Institute, Viterbi Family Department of Ophthalmology, University of California San Diego, La Jolla, CA 92093, USA; (T.B.); (V.A.N.H.); (Z.S.); (R.N.W.)
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4
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Burtscher V, Mount J, Huang J, Cowgill J, Chang Y, Bickel K, Chen J, Yuan P, Chanda B. Structural basis for hyperpolarization-dependent opening of human HCN1 channel. Nat Commun 2024; 15:5216. [PMID: 38890331 PMCID: PMC11189445 DOI: 10.1038/s41467-024-49599-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Accepted: 06/11/2024] [Indexed: 06/20/2024] Open
Abstract
Hyperpolarization and cyclic nucleotide (HCN) activated ion channels are critical for the automaticity of action potentials in pacemaking and rhythmic electrical circuits in the human body. Unlike most voltage-gated ion channels, the HCN and related plant ion channels activate upon membrane hyperpolarization. Although functional studies have identified residues in the interface between the voltage-sensing and pore domain as crucial for inverted electromechanical coupling, the structural mechanisms for this unusual voltage-dependence remain unclear. Here, we present cryo-electron microscopy structures of human HCN1 corresponding to Closed, Open, and a putative Intermediate state. Our structures reveal that the downward motion of the gating charges past the charge transfer center is accompanied by concomitant unwinding of the inner end of the S4 and S5 helices, disrupting the tight gating interface observed in the Closed state structure. This helix-coil transition at the intracellular gating interface accompanies a concerted iris-like dilation of the pore helices and underlies the reversed voltage dependence of HCN channels.
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Affiliation(s)
- Verena Burtscher
- Department of Anesthesiology, Washington University School of Medicine, Saint Louis, MO, USA
- Center for the Investigation of Membrane Excitability Diseases, Washington University School of Medicine, Saint Louis, MO, USA
| | - Jonathan Mount
- Center for the Investigation of Membrane Excitability Diseases, Washington University School of Medicine, Saint Louis, MO, USA
- Department of Cell Biology and Physiology, Washington University School of Medicine, Saint Louis, MO, USA
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Jian Huang
- Department of Chemistry, University of Massachusetts, Amherst, MA, USA
| | - John Cowgill
- Department of Anesthesiology, Washington University School of Medicine, Saint Louis, MO, USA
- Center for the Investigation of Membrane Excitability Diseases, Washington University School of Medicine, Saint Louis, MO, USA
- Department of Applied Physics, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Yongchang Chang
- Department of Anesthesiology, Washington University School of Medicine, Saint Louis, MO, USA
- Center for the Investigation of Membrane Excitability Diseases, Washington University School of Medicine, Saint Louis, MO, USA
| | - Kathleen Bickel
- Department of Anesthesiology, Washington University School of Medicine, Saint Louis, MO, USA
- Center for the Investigation of Membrane Excitability Diseases, Washington University School of Medicine, Saint Louis, MO, USA
| | - Jianhan Chen
- Department of Chemistry, University of Massachusetts, Amherst, MA, USA
| | - Peng Yuan
- Center for the Investigation of Membrane Excitability Diseases, Washington University School of Medicine, Saint Louis, MO, USA.
- Department of Cell Biology and Physiology, Washington University School of Medicine, Saint Louis, MO, USA.
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
| | - Baron Chanda
- Department of Anesthesiology, Washington University School of Medicine, Saint Louis, MO, USA.
- Center for the Investigation of Membrane Excitability Diseases, Washington University School of Medicine, Saint Louis, MO, USA.
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, Saint Louis, MO, USA.
- Department of Neuroscience, Washington University School of Medicine, Saint Louis, MO, USA.
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5
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Roberts JD. Nitric oxide regulation of fetal and newborn lung development and function. Nitric Oxide 2024; 147:13-25. [PMID: 38588917 PMCID: PMC11148871 DOI: 10.1016/j.niox.2024.04.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Revised: 03/21/2024] [Accepted: 04/05/2024] [Indexed: 04/10/2024]
Abstract
In the developing lung, nitric oxide (NO) and cyclic guanosine monophosphate (cGMP) signaling are essential in regulating lung formation and vascular tone. Animal studies have linked many anatomical and pathophysiological features of newborn lung disease to abnormalities in the NO/cGMP signaling system. They have demonstrated that driving this system with agonists and antagonists alleviates many of them. This research has spurred the rapid clinical development, testing, and application of several NO/cGMP-targeting therapies with the hope of treating and potentially preventing significant pediatric lung diseases. However, there are instances when the therapeutic effectiveness of these agents is limited. Studies indicate that injury-induced disruption of several critical components within the signaling system may hinder the promise of some of these therapies. Recent research has identified basic mechanisms that suppress NO/cGMP signaling in the injured newborn lung. They have also pinpointed biomarkers that offer insight into the activation of these pathogenic mechanisms and their influence on the NO/cGMP signaling system's integrity in vivo. Together, these will guide the development of new therapies to protect NO/cGMP signaling and safeguard newborn lung development and function. This review summarizes the important role of the NO/cGMP signaling system in regulating pulmonary development and function and our evolving understanding of how it is disrupted by newborn lung injury.
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Affiliation(s)
- Jesse D Roberts
- Cardiovascular Research Center of the General Medical Services and the Departments of Anesthesia, Critical Care and Pain Medicine, Pediatrics, and Medicine, Massachusetts General Hospital - East, 149 13th St, Boston, MA, USA; Harvard Medical School, Harvard University, Cambridge, MA, USA.
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6
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Ednacot EMQ, Nabhani A, Dinh DM, Morehouse BR. Pharmacological potential of cyclic nucleotide signaling in immunity. Pharmacol Ther 2024; 258:108653. [PMID: 38679204 DOI: 10.1016/j.pharmthera.2024.108653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2024] [Revised: 03/16/2024] [Accepted: 04/17/2024] [Indexed: 05/01/2024]
Abstract
Cyclic nucleotides are important signaling molecules that play many critical physiological roles including controlling cell fate and development, regulation of metabolic processes, and responding to changes in the environment. Cyclic nucleotides are also pivotal regulators in immune signaling, orchestrating intricate processes that maintain homeostasis and defend against pathogenic threats. This review provides a comprehensive examination of the pharmacological potential of cyclic nucleotide signaling pathways within the realm of immunity. Beginning with an overview of the fundamental roles of cAMP and cGMP as ubiquitous second messengers, this review delves into the complexities of their involvement in immune responses. Special attention is given to the challenges associated with modulating these signaling pathways for therapeutic purposes, emphasizing the necessity for achieving cell-type specificity to avert unintended consequences. A major focus of the review is on the recent paradigm-shifting discoveries regarding specialized cyclic nucleotide signals in the innate immune system, notably the cGAS-STING pathway. The significance of cyclic dinucleotides, exemplified by 2'3'-cGAMP, in controlling immune responses against pathogens and cancer, is explored. The evolutionarily conserved nature of cyclic dinucleotides as antiviral agents, spanning across diverse organisms, underscores their potential as targets for innovative immunotherapies. Findings from the last several years have revealed a striking diversity of novel bacterial cyclic nucleotide second messengers which are involved in antiviral responses. Knowledge of the existence and precise identity of these molecules coupled with accurate descriptions of their associated immune defense pathways will be essential to the future development of novel antibacterial therapeutic strategies. The insights presented herein may help researchers navigate the evolving landscape of immunopharmacology as it pertains to cyclic nucleotides and point toward new avenues or lines of thinking about development of therapeutics against the pathways they regulate.
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Affiliation(s)
- Eirene Marie Q Ednacot
- Department of Molecular Biology and Biochemistry, School of Biological Sciences, University of California Irvine, Irvine, CA 92697, USA; Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, University of California Irvine, Irvine, CA 92697, USA
| | - Ali Nabhani
- Department of Molecular Biology and Biochemistry, School of Biological Sciences, University of California Irvine, Irvine, CA 92697, USA
| | - David M Dinh
- Department of Molecular Biology and Biochemistry, School of Biological Sciences, University of California Irvine, Irvine, CA 92697, USA
| | - Benjamin R Morehouse
- Department of Molecular Biology and Biochemistry, School of Biological Sciences, University of California Irvine, Irvine, CA 92697, USA; Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, University of California Irvine, Irvine, CA 92697, USA; Institute for Immunology, University of California Irvine, Irvine, CA 92697, USA; Center for Virus Research, University of California Irvine, Irvine, CA 92697, USA.
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7
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Jurisch-Yaksi N, Wachten D, Gopalakrishnan J. The neuronal cilium - a highly diverse and dynamic organelle involved in sensory detection and neuromodulation. Trends Neurosci 2024; 47:383-394. [PMID: 38580512 DOI: 10.1016/j.tins.2024.03.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 03/04/2024] [Accepted: 03/14/2024] [Indexed: 04/07/2024]
Abstract
Cilia are fascinating organelles that act as cellular antennae, sensing the cellular environment. Cilia gained significant attention in the late 1990s after their dysfunction was linked to genetic diseases known as ciliopathies. Since then, several breakthrough discoveries have uncovered the mechanisms underlying cilia biogenesis and function. Like most cells in the animal kingdom, neurons also harbor cilia, which are enriched in neuromodulatory receptors. Yet, how neuronal cilia modulate neuronal physiology and animal behavior remains poorly understood. By comparing ciliary biology between the sensory and central nervous systems (CNS), we provide new perspectives on the functions of cilia in brain physiology.
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Affiliation(s)
- Nathalie Jurisch-Yaksi
- Department of Clinical and Molecular Medicine (IKOM), Faculty of Medicine and Health Science, Norwegian University of Science and Technology, Erling Skalgssons gate 1, 7491 Trondheim, Norway.
| | - Dagmar Wachten
- Department of Biophysical Imaging, Institute of Innate Immunity, Medical Faculty, University of Bonn, Venusberg-Campus 1, 53127 Bonn, Germany
| | - Jay Gopalakrishnan
- Institute of Human Genetics, University Hospital, Heinrich-Heine-Universität, 40225 Düsseldorf, Germany; Institute for Human Genetics, Universitätsklinikum Jena, Friedrich-Schiller-Universität Jena, 07740 Jena, Germany
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8
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Pliushcheuskaya P, Kesh S, Kaufmann E, Wucherpfennig S, Schwede F, Künze G, Nache V. Similar Binding Modes of cGMP Analogues Limit Selectivity in Modulating Retinal CNG Channels via the Cyclic Nucleotide-Binding Domain. ACS Chem Neurosci 2024; 15:1652-1668. [PMID: 38579109 PMCID: PMC11027099 DOI: 10.1021/acschemneuro.3c00665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Revised: 02/28/2024] [Accepted: 03/19/2024] [Indexed: 04/07/2024] Open
Abstract
In treating retinitis pigmentosa, a genetic disorder causing progressive vision loss, selective inhibition of rod cyclic nucleotide-gated (CNG) channels holds promise. Blocking the increased Ca2+-influx in rod photoreceptors through CNG channels can potentially delay disease progression and improve the quality of life for patients. To find inhibitors for rod CNG channels, we investigated the impact of 16 cGMP analogues on both rod and cone CNG channels using the patch-clamp technique. Although modifications at the C8 position of the guanine ring did not change the ligand efficacy, modifications at the N1 and N2 positions rendered cGMP largely ineffective in activating retinal CNG channels. Notably, PET-cGMP displayed selective potential, favoring rod over cone, whereas Rp-cGMPS showed greater efficiency in activating cone over rod CNG channels. Ligand docking and molecular dynamics simulations on cyclic nucleotide-binding domains showed comparable binding energies and binding modes for cGMP and its analogues in both rod and cone CNG channels (CNGA1 vs CNGA3 subunits). Computational experiments on CNGB1a vs CNGB3 subunits showed similar binding modes albeit with fewer amino acid interactions with cGMP due to an inactivated conformation of their C-helix. In addition, no clear correlation could be observed between the computational scores and the CNG channel efficacy values, suggesting additional factors beyond binding strength determining ligand selectivity and potency. This study highlights the importance of looking beyond the cyclic nucleotide-binding domain and toward the gating mechanism when searching for selective modulators. Future efforts in developing selective modulators for CNG channels should prioritize targeting alternative channel domains.
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Affiliation(s)
- Palina Pliushcheuskaya
- Institute
for Drug Discovery, Medical Faculty, University
of Leipzig, Leipzig 04103, Germany
| | - Sandeep Kesh
- Institute
of Physiology II, University Hospital Jena, Friedrich Schiller University
Jena, Jena 07743, Germany
| | - Emma Kaufmann
- Institute
of Physiology II, University Hospital Jena, Friedrich Schiller University
Jena, Jena 07743, Germany
| | - Sophie Wucherpfennig
- Institute
of Physiology II, University Hospital Jena, Friedrich Schiller University
Jena, Jena 07743, Germany
| | - Frank Schwede
- BIOLOG
Life Science Institute GmbH & Co KG, Bremen 28199, Germany
| | - Georg Künze
- Institute
for Drug Discovery, Medical Faculty, University
of Leipzig, Leipzig 04103, Germany
- Interdisciplinary
Center for Bioinformatics, University of
Leipzig, Leipzig 04107, Germany
- Center
for Scalable Data Analytics and Artificial Intelligence, University of Leipzig, Leipzig 04105, Germany
| | - Vasilica Nache
- Institute
of Physiology II, University Hospital Jena, Friedrich Schiller University
Jena, Jena 07743, Germany
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9
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Hill TJ, Sengupta P. Feedforward and feedback mechanisms cooperatively regulate rapid experience-dependent response adaptation in a single thermosensory neuron type. Proc Natl Acad Sci U S A 2024; 121:e2321430121. [PMID: 38530893 PMCID: PMC10998601 DOI: 10.1073/pnas.2321430121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Accepted: 02/27/2024] [Indexed: 03/28/2024] Open
Abstract
Sensory adaptation allows neurons to adjust their sensitivity and responses based on recent experience. The mechanisms that mediate continuous adaptation to stimulus history over seconds- to hours-long timescales, and whether these mechanisms can operate within a single sensory neuron type, are unclear. The single pair of AFD thermosensory neurons in Caenorhabditis elegans exhibits experience-dependent plasticity in their temperature response thresholds on both minutes- and hours-long timescales upon a temperature upshift. While long-term response adaptation requires changes in gene expression in AFD, the mechanisms driving rapid response plasticity are unknown. Here, we show that rapid thermosensory response adaptation in AFD is mediated via cGMP and calcium-dependent feedforward and feedback mechanisms operating at the level of primary thermotransduction. We find that either of two thermosensor receptor guanylyl cyclases (rGCs) alone is sufficient to drive rapid adaptation, but that each rGC drives adaptation at different rates. rGC-driven adaptation is mediated in part via phosphorylation of their intracellular domains, and calcium-dependent feedback regulation of basal cGMP levels via a neuronal calcium sensor protein. In turn, cGMP levels feedforward via cGMP-dependent protein kinases to phosphorylate a specific subunit of the cGMP-gated thermotransduction channel to further regulate rapid adaptation. Our results identify multiple molecular pathways that act in AFD to ensure rapid adaptation to a temperature change and indicate that the deployment of both transcriptional and nontranscriptional mechanisms within a single sensory neuron type can contribute to continuous sensory adaptation.
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Affiliation(s)
- Tyler J. Hill
- Department of Biology, Brandeis University, Waltham, MA02454
| | - Piali Sengupta
- Department of Biology, Brandeis University, Waltham, MA02454
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10
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Bastola T, Perkins GA, Huu VAN, Ju S, Kim KY, Shen Z, Skowronska-Krawczyk D, Weinreb RN, Ju WK. Activating soluble adenylyl cyclase protects mitochondria, rescues retinal ganglion cells, and ameliorates visual dysfunction caused by oxidative stress. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.04.583371. [PMID: 38496531 PMCID: PMC10942326 DOI: 10.1101/2024.03.04.583371] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/19/2024]
Abstract
Oxidative stress is a key factor causing mitochondrial dysfunction and retinal ganglion cell (RGC) death in glaucomatous neurodegeneration. The cyclic adenosine monophosphate (cAMP)/protein kinase A (PKA) signaling pathway is involved in mitochondrial protection, promoting RGC survival. Soluble adenylyl cyclase (sAC) is one of the key regulators of the cAMP/PKA signaling pathway. However, the precise molecular mechanisms underlying the sAC-mediated signaling pathway and mitochondrial protection in RGCs that counter oxidative stress are not well characterized. Here, we demonstrate that sAC plays a critical role in protecting RGC mitochondria from oxidative stress. Using mouse models of oxidative stress, we found that activating sAC protected RGCs, blocked AMP-activated protein kinase activation, inhibited glial activation, and improved visual function. Moreover, we found that this is the result of preserving mitochondrial dynamics (fusion and fission), promoting mitochondrial bioenergetics and biogenesis, and preventing metabolic stress and apoptotic cell death in a paraquat oxidative stress model. Notably, sAC activation ameliorated mitochondrial dysfunction in RGCs by enhancing mitochondrial biogenesis, preserving mitochondrial structure, and increasing ATP production in oxidatively stressed RGCs. These findings suggest that activating sAC enhances the mitochondrial structure and function in RGCs to counter oxidative stress, consequently promoting RGC protection. We propose that modulation of the sAC-mediated signaling pathway has therapeutic potential acting on RGC mitochondria for treating glaucoma and other retinal diseases.
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11
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Kim EY, Kim MH, Yun SD, Lee SK, Kim EJ, Kim JH, Oh SA, Kim YJ, Jung KH, Park SK. Redundant role of OsCNGC4 and OsCNGC5 encoding cyclic nucleotide-gated channels in rice pollen germination and tube growth. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2024; 208:108522. [PMID: 38493663 DOI: 10.1016/j.plaphy.2024.108522] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2024] [Accepted: 03/09/2024] [Indexed: 03/19/2024]
Abstract
In staple crops, such as rice (Oryza sativa L.), pollen plays a crucial role in seed production. However, the molecular mechanisms underlying rice pollen germination and tube growth remain underexplored. Notably, we recently uncovered the redundant expression and mutual interaction of two rice genes encoding cyclic nucleotide-gated channels (CNGCs), OsCNGC4 and OsCNGC5, in mature pollen. Building on these findings, the current study focused on clarifying the functional roles of these two genes in pollen germination and tube growth. To overcome functional redundancy, we produced gene-edited rice plants with mutations in both genes using the CRISPR-Cas9 system. The resulting homozygous OsCNGC4 and OsCNGC5 gene-edited mutants (oscngc4/5) exhibited significantly lower pollen germination rates than the wild type (WT), along with severely reduced fertility. Transcriptome analysis of the double oscngc4/5 mutant revealed downregulation of genes related to receptor kinases, transporters, and cell wall metabolism. To identify the direct regulators of OsCNGC4, which form a heterodimer with OsCNGC5, we screened a yeast two-hybrid library containing rice cDNAs from mature anthers. Subsequently, we identified two calmodulin isoforms (CaM1-1 and CaM1-2), NETWORKED 2 A (NET2A), and proline-rich extension-like receptor kinase 13 (PERK13) proteins as interactors of OsCNGC4, suggesting its roles in regulating Ca2+ channel activity and F-actin organization. Overall, our results suggest that OsCNGC4 and OsCNGC5 may play critical roles in pollen germination and elongation by regulating the Ca2+ gradient in growing pollen tubes.
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Affiliation(s)
- Eun Young Kim
- School of Applied Biosciences, Kyungpook National University, Daegu, 41566, Republic of Korea
| | - Myung-Hee Kim
- School of Applied Biosciences, Kyungpook National University, Daegu, 41566, Republic of Korea; Genomics Division, Department of Agricultural Bio-Resources, National Institute of Agricultural Sciences, Rural Development Administration, Wansan-gu, Jeonju, 54874, Republic of Korea
| | - Sang Dae Yun
- School of Applied Biosciences, Kyungpook National University, Daegu, 41566, Republic of Korea
| | - Su-Kyoung Lee
- Graduate School of Green Bio-Science & Crop Biotech Institute, Kyung Hee University, Yongin, 17104, Republic of Korea
| | - Eui-Jung Kim
- Graduate School of Green Bio-Science & Crop Biotech Institute, Kyung Hee University, Yongin, 17104, Republic of Korea
| | - Ji-Hyun Kim
- Department of Life Science and Environmental Biochemistry, Pusan National University, Miryang, 50463, Republic of Korea
| | - Sung-Aeong Oh
- School of Applied Biosciences, Kyungpook National University, Daegu, 41566, Republic of Korea
| | - Yu-Jin Kim
- Department of Life Science and Environmental Biochemistry, Pusan National University, Miryang, 50463, Republic of Korea
| | - Ki-Hong Jung
- Graduate School of Green Bio-Science & Crop Biotech Institute, Kyung Hee University, Yongin, 17104, Republic of Korea.
| | - Soon Ki Park
- School of Applied Biosciences, Kyungpook National University, Daegu, 41566, Republic of Korea.
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12
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Ujfalusi-Pozsonyi K, Bódis E, Nyitrai M, Kengyel A, Telek E, Pécsi I, Fekete Z, Varnyuné Kis-Bicskei N, Mas C, Moussaoui D, Pernot P, Tully MD, Weik M, Schirò G, Kapetanaki SM, Lukács A. ATP-dependent conformational dynamics in a photoactivated adenylate cyclase revealed by fluorescence spectroscopy and small-angle X-ray scattering. Commun Biol 2024; 7:147. [PMID: 38307988 PMCID: PMC10837130 DOI: 10.1038/s42003-024-05842-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2023] [Accepted: 01/22/2024] [Indexed: 02/04/2024] Open
Abstract
Structural insights into the photoactivated adenylate cyclases can be used to develop new ways of controlling cellular cyclic adenosine monophosphate (cAMP) levels for optogenetic and other applications. In this work, we use an integrative approach that combines biophysical and structural biology methods to provide insight on the interaction of adenosine triphosphate (ATP) with the dark-adapted state of the photoactivated adenylate cyclase from the cyanobacterium Oscillatoria acuminata (OaPAC). A moderate affinity of the nucleotide for the enzyme was calculated and the thermodynamic parameters of the interaction have been obtained. Stopped-flow fluorescence spectroscopy and small-angle solution scattering have revealed significant conformational changes in the enzyme, presumably in the adenylate cyclase (AC) domain during the allosteric mechanism of ATP binding to OaPAC with small and large-scale movements observed to the best of our knowledge for the first time in the enzyme in solution upon ATP binding. These results are in line with previously reported drastic conformational changes taking place in several class III AC domains upon nucleotide binding.
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Affiliation(s)
- K Ujfalusi-Pozsonyi
- Department of Biophysics, Medical School, University of Pécs, 7624, Pécs, Hungary
| | - E Bódis
- Department of Biophysics, Medical School, University of Pécs, 7624, Pécs, Hungary
| | - M Nyitrai
- Department of Biophysics, Medical School, University of Pécs, 7624, Pécs, Hungary
| | - A Kengyel
- Department of Biophysics, Medical School, University of Pécs, 7624, Pécs, Hungary
| | - E Telek
- Department of Biophysics, Medical School, University of Pécs, 7624, Pécs, Hungary
| | - I Pécsi
- Department of Biophysics, Medical School, University of Pécs, 7624, Pécs, Hungary
| | - Z Fekete
- Department of Biophysics, Medical School, University of Pécs, 7624, Pécs, Hungary
| | | | - C Mas
- Univ. Grenoble Alpes, CNRS, CEA, EMBL, ISBG, F-38000, Grenoble, France
| | - D Moussaoui
- European Synchrotron Radiation Facility (ESRF), Grenoble, France
| | - P Pernot
- European Synchrotron Radiation Facility (ESRF), Grenoble, France
| | - M D Tully
- European Synchrotron Radiation Facility (ESRF), Grenoble, France
| | - M Weik
- Institut de Biologie Structurale (IBS), Université Grenoble Alpes, CEA, CNRS, Grenoble, France
| | - G Schirò
- Institut de Biologie Structurale (IBS), Université Grenoble Alpes, CEA, CNRS, Grenoble, France
| | - S M Kapetanaki
- Institut de Biologie Structurale (IBS), Université Grenoble Alpes, CEA, CNRS, Grenoble, France.
- Department of Biophysics, Medical School, University of Pécs, 7624, Pécs, Hungary.
| | - A Lukács
- Department of Biophysics, Medical School, University of Pécs, 7624, Pécs, Hungary.
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13
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Paudel D, Uehara O, Giri S, Morikawa T, Yoshida K, Kitagawa T, Ariwansa D, Acharya N, Ninomiya K, Kuramitsu Y, Ohta T, Kobayashi M, Abiko Y. Transcriptomic analysis of the submandibular gland under psychological stress condition. J Oral Pathol Med 2024; 53:150-158. [PMID: 38291254 DOI: 10.1111/jop.13512] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2023] [Revised: 12/01/2023] [Accepted: 01/18/2024] [Indexed: 02/01/2024]
Abstract
BACKGROUND Psychological stress is associated with changes in salivary flow and composition. However, studies to show the effect of psychological stress on the transcriptome of the salivary gland are limited. This study aims to perform a transcriptomic analysis of the submandibular gland under psychological stress using a chronic restraint stress model of rats. METHODS Sprague-Dawley rats were divided into stress groups and control groups. Psychological stress was induced in the stress group rats by enclosing them in a plastic tube for 4 h daily over 6 weeks. RNA sequencing was performed on RNA extracted from the submandibular gland. The differentially expressed genes were identified, and the genes of interest were further validated using qRT-PCR, immunofluorescence, and western blot. RESULTS A comparison between control and stress groups showed 45 differentially expressed genes. The top five altered genes in RNA sequencing data showed similar gene expression in qRT-PCR validation. The most downregulated gene in the stress group, FosB, was a gene of interest and was further validated for its protein-level expression using immunofluorescence and western blot. The genesets for gene ontology cellular component, molecular function, and KEGG showed that pathways related to ribosome biosynthesis and function were downregulated in the stress group compared to the control. CONCLUSION Psychological stress showed transcriptomic alteration in the submandibular gland. The findings may be important in understanding stress-related oral diseases.
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Affiliation(s)
- Durga Paudel
- Advanced Research Promotion Center, Health Sciences University of Hokkaido, Hokkaido, Japan
| | - Osamu Uehara
- Division of Molecular Epidemiology and Disease Control, School of Dentistry, Health Sciences University of Hokkaido, Hokkaido, Japan
| | - Sarita Giri
- Advanced Research Promotion Center, Health Sciences University of Hokkaido, Hokkaido, Japan
| | - Tetsuro Morikawa
- Division of Oral Medicine and Pathology, School of Dentistry, Health Sciences University of Hokkaido, Hokkaido, Japan
| | - Koki Yoshida
- Division of Oral Medicine and Pathology, School of Dentistry, Health Sciences University of Hokkaido, Hokkaido, Japan
| | - Takao Kitagawa
- Advanced Research Promotion Center, Health Sciences University of Hokkaido, Hokkaido, Japan
| | - Dedy Ariwansa
- Division of Oral Medicine and Pathology, School of Dentistry, Health Sciences University of Hokkaido, Hokkaido, Japan
| | - Nisha Acharya
- Maharajgunj Medical Campus, Institute of Medicine, Tribhuvan University, Kathmandu, Nepal
| | - Kazunori Ninomiya
- Department of Pharmacology, The Nippon Dental University School of Life Dentistry at Niigata, Niigata, Japan
| | - Yasuhiro Kuramitsu
- Advanced Research Promotion Center, Health Sciences University of Hokkaido, Hokkaido, Japan
| | - Tohru Ohta
- Advanced Research Promotion Center, Health Sciences University of Hokkaido, Hokkaido, Japan
| | - Masanobu Kobayashi
- Advanced Research Promotion Center, Health Sciences University of Hokkaido, Hokkaido, Japan
| | - Yoshihiro Abiko
- Division of Oral Medicine and Pathology, School of Dentistry, Health Sciences University of Hokkaido, Hokkaido, Japan
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14
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Yang Z, Yan L, Zhang W, Qi J, An W, Yao K. Dyschromatopsia: a comprehensive analysis of mechanisms and cutting-edge treatments for color vision deficiency. Front Neurosci 2024; 18:1265630. [PMID: 38298913 PMCID: PMC10828017 DOI: 10.3389/fnins.2024.1265630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2023] [Accepted: 01/02/2024] [Indexed: 02/02/2024] Open
Abstract
Color blindness is a retinal disease that mainly manifests as a color vision disorder, characterized by achromatopsia, red-green color blindness, and blue-yellow color blindness. With the development of technology and progress in theory, extensive research has been conducted on the genetic basis of color blindness, and various approaches have been explored for its treatment. This article aims to provide a comprehensive review of recent advances in understanding the pathological mechanism, clinical symptoms, and treatment options for color blindness. Additionally, we discuss the various treatment approaches that have been developed to address color blindness, including gene therapy, pharmacological interventions, and visual aids. Furthermore, we highlight the promising results from clinical trials of these treatments, as well as the ongoing challenges that must be addressed to achieve effective and long-lasting therapeutic outcomes. Overall, this review provides valuable insights into the current state of research on color blindness, with the intention of informing further investigation and development of effective treatments for this disease.
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Affiliation(s)
- Zihao Yang
- Institute of Visual Neuroscience and Stem Cell Engineering, Wuhan University of Science and Technology, Wuhan, China
- College of Life Sciences and Health, Wuhan University of Science and Technology, Wuhan, China
| | - Lin Yan
- Institute of Visual Neuroscience and Stem Cell Engineering, Wuhan University of Science and Technology, Wuhan, China
- College of Life Sciences and Health, Wuhan University of Science and Technology, Wuhan, China
| | - Wenliang Zhang
- Institute of Visual Neuroscience and Stem Cell Engineering, Wuhan University of Science and Technology, Wuhan, China
- College of Life Sciences and Health, Wuhan University of Science and Technology, Wuhan, China
| | - Jia Qi
- Institute of Visual Neuroscience and Stem Cell Engineering, Wuhan University of Science and Technology, Wuhan, China
- College of Life Sciences and Health, Wuhan University of Science and Technology, Wuhan, China
| | - Wenjing An
- Institute of Visual Neuroscience and Stem Cell Engineering, Wuhan University of Science and Technology, Wuhan, China
- College of Life Sciences and Health, Wuhan University of Science and Technology, Wuhan, China
| | - Kai Yao
- Institute of Visual Neuroscience and Stem Cell Engineering, Wuhan University of Science and Technology, Wuhan, China
- College of Life Sciences and Health, Wuhan University of Science and Technology, Wuhan, China
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15
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Derby CD, Caprio J. What are olfaction and gustation, and do all animals have them? Chem Senses 2024; 49:bjae009. [PMID: 38422390 DOI: 10.1093/chemse/bjae009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Indexed: 03/02/2024] Open
Abstract
Different animals have distinctive anatomical and physiological properties to their chemical senses that enhance detection and discrimination of relevant chemical cues. Humans and other vertebrates are recognized as having 2 main chemical senses, olfaction and gustation, distinguished from each other by their evolutionarily conserved neuroanatomical organization. This distinction between olfaction and gustation in vertebrates is not based on the medium in which they live because the most ancestral and numerous vertebrates, the fishes, live in an aquatic habitat and thus both olfaction and gustation occur in water and both can be of high sensitivity. The terms olfaction and gustation have also often been applied to the invertebrates, though not based on homology. Consequently, any similarities between olfaction and gustation in the vertebrates and invertebrates have resulted from convergent adaptations or shared constraints during evolution. The untidiness of assigning olfaction and gustation to invertebrates has led some to recommend abandoning the use of these terms and instead unifying them and others into a single category-chemical sense. In our essay, we compare the nature of the chemical senses of diverse animal types and consider their designation as olfaction, oral gustation, extra-oral gustation, or simply chemoreception. Properties that we have found useful in categorizing chemical senses of vertebrates and invertebrates include the nature of peripheral sensory cells, organization of the neuropil in the processing centers, molecular receptor specificity, and function.
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Affiliation(s)
- Charles D Derby
- Neuroscience Institute, Georgia State University, Atlanta, GA, United States
| | - John Caprio
- Department of Biological Sciences, Louisiana State University, Baton Rouge, LA, United States
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16
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Hill TJ, Sengupta P. Feedforward and feedback mechanisms cooperatively regulate rapid experience-dependent response adaptation in a single thermosensory neuron type. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.05.570166. [PMID: 38168209 PMCID: PMC10760192 DOI: 10.1101/2023.12.05.570166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Sensory adaptation allows neurons to adjust their sensitivity and responses based on recent experience. The mechanisms that mediate continuous adaptation to stimulus history over seconds to hours long timescales, and whether these mechanisms can operate within a single sensory neuron type, are unclear. The single pair of AFD thermosensory neurons in C. elegans exhibits experience-dependent plasticity in their temperature response thresholds on both minutes- and hours-long timescales upon a temperature upshift. While long-term response adaptation requires changes in gene expression in AFD, the mechanisms driving rapid response plasticity are unknown. Here, we show that rapid thermosensory response adaptation in AFD is mediated via cGMP and calcium-dependent feedforward and feedback mechanisms operating at the level of primary thermotransduction. We find that either of two thermosensor receptor guanylyl cyclases (rGCs) alone is sufficient to drive rapid adaptation, but that each rGC drives adaptation at different rates. rGC-driven adaptation is mediated in part via phosphorylation of their intracellular domains, and calcium-dependent feedback regulation of basal cGMP levels via a neuronal calcium sensor protein. In turn, cGMP levels feedforward via cGMP-dependent protein kinases to phosphorylate a specific subunit of the cGMP-gated thermotransduction channel to further regulate rapid adaptation. Our results identify multiple molecular pathways that act in AFD to ensure rapid adaptation to a temperature change, and indicate that the deployment of both transcriptional and non-transcriptional mechanisms within a single sensory neuron type can contribute to continuous sensory adaptation.
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Affiliation(s)
- Tyler J. Hill
- Department of Biology, Brandeis University, Waltham, MA 02454
| | - Piali Sengupta
- Department of Biology, Brandeis University, Waltham, MA 02454
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17
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Hu Z, Yang J. Structural basis of properties, mechanisms, and channelopathy of cyclic nucleotide-gated channels. Channels (Austin) 2023; 17:2273165. [PMID: 37905307 PMCID: PMC10761061 DOI: 10.1080/19336950.2023.2273165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Accepted: 10/07/2023] [Indexed: 11/02/2023] Open
Abstract
Recent years have seen an outpouring of atomic or near atomic resolution structures of cyclic nucleotide-gated (CNG) channels, captured in closed, transition, pre-open, partially open, and fully open states. These structures provide unprecedented molecular insights into the activation, assembly, architecture, regulation, and channelopathy of CNG channels, as well as mechanistic explanations for CNG channel biophysical and pharmacological properties. This article summarizes recent advances in CNG channel structural biology, describes key structural features and elements, and illuminates a detailed conformational landscape of activation by cyclic nucleotides. The review also correlates structures with findings and properties delineated in functional studies, including nonselective monovalent cation selectivity, Ca2+ permeation and block, block by L-cis-diltiazem, location of the activation gate, lack of voltage-dependent gating, and modulation by lipids and calmodulin. A perspective on future research is also offered.
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Affiliation(s)
- Zhengshan Hu
- Department of Biological Sciences, Columbia University, New York, NY, USA
| | - Jian Yang
- Department of Biological Sciences, Columbia University, New York, NY, USA
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18
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Solaki M, Wissinger B, Kohl S, Reuter P. Functional evaluation allows ACMG/AMP-based re-classification of CNGA3 variants associated with achromatopsia. Genet Med 2023; 25:100979. [PMID: 37689994 DOI: 10.1016/j.gim.2023.100979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 08/30/2023] [Accepted: 08/30/2023] [Indexed: 09/11/2023] Open
Abstract
PURPOSE CNGA3 encoding the main subunit of the cyclic nucleotide-gated ion channel in cone photoreceptors is one of the major disease-associated genes for achromatopsia. Most CNGA3 variants are missense variants with the majority being functionally uncharacterized and therefore hampering genetic diagnosis. In light of potential gene therapy, objective variant pathogenicity assessment is essential. METHODS We established a medium-throughput aequorin-based luminescence bioassay allowing mutant CNGA3 channel function assessment via quantification of CNGA3 channel-mediated calcium influx in a cell culture system, thereby enabling American College of Medical Genetics and Genomics/Association for Molecular Pathology-based variant re-classification. RESULTS We provide functional read-out obtained for 150 yet uncharacterized CNGA3 missense substitutions of which 55 were previously categorized as variants of uncertain significance (VUS) identifying 25 as functionally normal and 125 as functionally abnormal. These data enabled the American College of Medical Genetics and Genomics/ Association for Molecular Pathology-based variant re-classification of 52/55 VUS as either benign, likely benign, or likely pathogenic reaching a VUS re-classification rate of 94.5%. CONCLUSION Our aequorin-based bioassay allows functionally ensured clinical variant interpretation for 150 CNGA3 missense variants enabling and supporting VUS re-classification and assuring molecular diagnosis to patients affected by CNGA3-associated achromatopsia, hereby identifying patients eligible for future gene therapy trials on this disease.
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Affiliation(s)
- Maria Solaki
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, Tübingen, Germany
| | - Bernd Wissinger
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, Tübingen, Germany
| | - Susanne Kohl
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, Tübingen, Germany.
| | - Peggy Reuter
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, Tübingen, Germany.
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19
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Orlowski J. An ion transporter in sperm that has features of a channel. Nature 2023; 623:38-40. [PMID: 37880527 DOI: 10.1038/d41586-023-03154-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2023]
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20
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Montoya-Durango D, Walter MN, Rodriguez W, Wang Y, Chariker JH, Rouchka EC, Maldonado C, Barve S, McClain CJ, Gobejishvili L. Dysregulated Cyclic Nucleotide Metabolism in Alcohol-Associated Steatohepatitis: Implications for Novel Targeted Therapies. BIOLOGY 2023; 12:1321. [PMID: 37887031 PMCID: PMC10604143 DOI: 10.3390/biology12101321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Revised: 09/29/2023] [Accepted: 10/09/2023] [Indexed: 10/28/2023]
Abstract
BACKGROUND Cyclic nucleotides are second messengers, which play significant roles in numerous biological processes. Previous work has shown that cAMP and cGMP signaling regulates various pathways in liver cells, including Kupffer cells, hepatocytes, hepatic stellate cells, and cellular components of hepatic sinusoids. Importantly, it has been shown that cAMP levels and enzymes involved in cAMP homeostasis are affected by alcohol. Although the role of cyclic nucleotide signaling is strongly implicated in several pathological pathways in liver diseases, studies describing the changes in genes regulating cyclic nucleotide metabolism in ALD are lacking. METHODS Male C57B/6 mice were used in an intragastric model of alcohol-associated steatohepatitis (ASH). Liver injury, inflammation, and fibrogenesis were evaluated by measuring plasma levels of injury markers, liver tissue cytokines, and gene expression analyses. Liver transcriptome analysis was performed to examine the effects of alcohol on regulators of cyclic AMP and GMP levels and signaling. cAMP and cGMP levels were measured in mouse livers as well as in livers from healthy human donors and patients with alcohol-associated hepatitis (AH). RESULTS Our results show significant changes in several phosphodiesterases (PDEs) with specificity to degrade cAMP (Pde4a, Pde4d, and Pde8a) and cGMP (Pde5a, Pde6d, and Pde9a), as well as dual-specificity PDEs (Pde1a and Pde10a) in ASH mouse livers. Adenylyl cyclases (ACs) 7 and 9, which are responsible for cAMP generation, were also affected by alcohol. Importantly, adenosine receptor 1, which has been implicated in the pathogenesis of liver diseases, was significantly increased by alcohol. Adrenoceptors 1 and 3 (Adrb), which couple with stimulatory G protein to regulate cAMP and cGMP signaling, were significantly decreased. Additionally, beta arrestin 2, which interacts with cAMP-specific PDE4D to desensitize G-protein-coupled receptor to generate cAMP, was significantly increased by alcohol. Notably, we observed that cAMP levels are much higher than cGMP levels in the livers of humans and mice; however, alcohol affected them differently. Specifically, cGMP levels were higher in patients with AH and ASH mice livers compared with controls. As expected, these changes in liver cyclic nucleotide signaling were associated with increased inflammation, steatosis, apoptosis, and fibrogenesis. CONCLUSIONS These data strongly implicate dysregulated cAMP and cGMP signaling in the pathogenesis of ASH. Future studies to identify changes in these regulators in a cell-specific manner could lead to the development of novel targeted therapies for ASH.
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Affiliation(s)
- Diego Montoya-Durango
- Department of Physiology, School of Medicine, University of Louisville, Louisville, KY 40290, USA; (D.M.-D.); (M.N.W.); (W.R.); (Y.W.); (C.M.)
| | - Mary Nancy Walter
- Department of Physiology, School of Medicine, University of Louisville, Louisville, KY 40290, USA; (D.M.-D.); (M.N.W.); (W.R.); (Y.W.); (C.M.)
| | - Walter Rodriguez
- Department of Physiology, School of Medicine, University of Louisville, Louisville, KY 40290, USA; (D.M.-D.); (M.N.W.); (W.R.); (Y.W.); (C.M.)
| | - Yali Wang
- Department of Physiology, School of Medicine, University of Louisville, Louisville, KY 40290, USA; (D.M.-D.); (M.N.W.); (W.R.); (Y.W.); (C.M.)
| | - Julia H. Chariker
- Department of Neuroscience Training, University of Louisville, Louisville, KY 40290, USA;
- KY INBRE Bioinformatics Core, University of Louisville, Louisville, KY 40290, USA;
| | - Eric C. Rouchka
- KY INBRE Bioinformatics Core, University of Louisville, Louisville, KY 40290, USA;
- Department of Biochemistry and Molecular Genetics, University of Louisville, Louisville, KY 40292, USA
| | - Claudio Maldonado
- Department of Physiology, School of Medicine, University of Louisville, Louisville, KY 40290, USA; (D.M.-D.); (M.N.W.); (W.R.); (Y.W.); (C.M.)
| | - Shirish Barve
- Department of Medicine, School of Medicine, University of Louisville, Louisville, KY 40290, USA; (S.B.); (C.J.M.)
- Alcohol Research Center, University of Louisville, Louisville, KY 40290, USA
| | - Craig J. McClain
- Department of Medicine, School of Medicine, University of Louisville, Louisville, KY 40290, USA; (S.B.); (C.J.M.)
- Alcohol Research Center, University of Louisville, Louisville, KY 40290, USA
- Robley Rex VA Medical Center, Louisville, KY 40206, USA
- Department of Pharmacology & Toxicology, School of Medicine, University of Louisville, Louisville, KY 40290, USA
| | - Leila Gobejishvili
- Department of Physiology, School of Medicine, University of Louisville, Louisville, KY 40290, USA; (D.M.-D.); (M.N.W.); (W.R.); (Y.W.); (C.M.)
- Department of Medicine, School of Medicine, University of Louisville, Louisville, KY 40290, USA; (S.B.); (C.J.M.)
- Alcohol Research Center, University of Louisville, Louisville, KY 40290, USA
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Schmauder R, Eick T, Schulz E, Sammler G, Voigt E, Mayer G, Ginter H, Ditze G, Benndorf K. Fast functional mapping of ligand-gated ion channels. Commun Biol 2023; 6:1003. [PMID: 37783870 PMCID: PMC10545696 DOI: 10.1038/s42003-023-05340-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Accepted: 09/11/2023] [Indexed: 10/04/2023] Open
Abstract
Ligand-gated ion channels are formed by three to five subunits that control the opening of the pore in a cooperative fashion. We developed a microfluidic chip-based technique for studying ion currents and fluorescence signals in either excised membrane patches or whole cells to measure activation and deactivation kinetics of the channels as well as ligand binding and unbinding when using confocal patch-clamp fluorometry. We show how this approach produces in a few seconds either unidirectional concentration-activation relationships at or near equilibrium and, moreover, respective time courses of activation and deactivation for a large number of freely designed steps of the ligand concentration. The short measuring period strongly minimizes the contribution of disturbing superimposing effects such as run-down phenomena and desensitization effects. To validate gating mechanisms, complex kinetic schemes are quantified without the requirement to have data at equilibrium. The new method has potential for functionally analyzing any ligand-gated ion channel and, beyond, also for other receptors.
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Affiliation(s)
- Ralf Schmauder
- Institut für Physiologie II, Universitätsklinikum Jena, Friedrich-Schiller-Universität Jena, 07743, Jena, Germany.
| | - Thomas Eick
- Institut für Physiologie II, Universitätsklinikum Jena, Friedrich-Schiller-Universität Jena, 07743, Jena, Germany
| | - Eckhard Schulz
- Hochschule Schmalkalden, Fakultät Elektrotechnik, Blechhammer, 98574, Schmalkalden, Germany
| | - Günther Sammler
- Zentrale Forschungswerkstätten, Universitätsklinikum Jena, Friedrich-Schiller-Universität Jena, 07743, Jena, Germany
| | - Elmar Voigt
- Leibniz Institut für Photonische Technologien e.V., Albert-Einstein-Straße 9, 07745, Jena, Germany
| | - Günter Mayer
- Leibniz Institut für Photonische Technologien e.V., Albert-Einstein-Straße 9, 07745, Jena, Germany
| | - Holger Ginter
- Zentrale Forschungswerkstätten, Universitätsklinikum Jena, Friedrich-Schiller-Universität Jena, 07743, Jena, Germany
| | - Günter Ditze
- Zentrale Forschungswerkstätten, Universitätsklinikum Jena, Friedrich-Schiller-Universität Jena, 07743, Jena, Germany
| | - Klaus Benndorf
- Institut für Physiologie II, Universitätsklinikum Jena, Friedrich-Schiller-Universität Jena, 07743, Jena, Germany.
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Benko F, Urminská D, Ďuračka M, Tvrdá E. Signaling Roleplay between Ion Channels during Mammalian Sperm Capacitation. Biomedicines 2023; 11:2519. [PMID: 37760960 PMCID: PMC10525812 DOI: 10.3390/biomedicines11092519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2023] [Revised: 08/31/2023] [Accepted: 09/06/2023] [Indexed: 09/29/2023] Open
Abstract
In order to accomplish their primary goal, mammalian spermatozoa must undergo a series of physiological, biochemical, and functional changes crucial for the acquisition of fertilization ability. Spermatozoa are highly polarized cells, which must swiftly respond to ionic changes on their passage through the female reproductive tract, and which are necessary for male gametes to acquire their functional competence. This review summarizes the current knowledge about specific ion channels and transporters located in the mammalian sperm plasma membrane, which are intricately involved in the initiation of changes within the ionic milieu of the sperm cell, leading to variations in the sperm membrane potential, membrane depolarization and hyperpolarization, changes in sperm motility and capacitation to further lead to the acrosome reaction and sperm-egg fusion. We also discuss the functionality of selected ion channels in male reproductive health and/or disease since these may become promising targets for clinical management of infertility in the future.
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Affiliation(s)
- Filip Benko
- Institute of Biotechnology, Faculty of Biotechnology and Food Sciences, Slovak University of Agriculture in Nitra, Tr. A. Hlinku 2, 949 76 Nitra, Slovakia; (D.U.); (E.T.)
| | - Dana Urminská
- Institute of Biotechnology, Faculty of Biotechnology and Food Sciences, Slovak University of Agriculture in Nitra, Tr. A. Hlinku 2, 949 76 Nitra, Slovakia; (D.U.); (E.T.)
| | - Michal Ďuračka
- AgroBioTech Research Centre, Slovak University of Agriculture in Nitra, Tr. A. Hlinku 2, 949 76 Nitra, Slovakia;
| | - Eva Tvrdá
- Institute of Biotechnology, Faculty of Biotechnology and Food Sciences, Slovak University of Agriculture in Nitra, Tr. A. Hlinku 2, 949 76 Nitra, Slovakia; (D.U.); (E.T.)
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23
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Muangkram Y, Himeno Y, Amano A. Clarifying the composition of the ATP consumption factors required for maintaining ion homeostasis in mouse rod photoreceptors. Sci Rep 2023; 13:14161. [PMID: 37644037 PMCID: PMC10465610 DOI: 10.1038/s41598-023-40663-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Accepted: 08/16/2023] [Indexed: 08/31/2023] Open
Abstract
To date, no effective treatment has been established for photoreceptor loss due to energy imbalances, but numerous therapeutic approaches have reported some success in slowing photoreceptor degeneration by downregulating energy demand. However, the detailed mechanisms remain unclear. This study aimed to clarify the composition of ATP consumption factors in photoreceptors in darkness and in light. We introduced mathematical formulas for ionic current activities combined with a phototransduction model to form a new mathematical model for estimating the energy expenditure of each ionic current. The proposed model included various ionic currents identified in mouse rods using a gene expression database incorporating an available electrophysiological recording of each specific gene. ATP was mainly consumed by Na+/K+-ATPase and plasma membrane Ca2+-ATPase pumps to remove excess Na+ and Ca2+. The rod consumed 7 [Formula: see text] 107 molecules of ATP s-1, where 65% was used to remove ions from the cyclic nucleotide-gated channel and 20% from the hyperpolarization-activated current in darkness. Increased light intensity raised the energy requirements of the complex phototransduction cascade mechanisms. Nevertheless, the overall energy consumption was less than that in darkness due to the significant reduction in ATPase activities, where the hyperpolarization-activated current proportion increased to 83%. A better understanding of energy demand/supply may provide an effective tool for investigating retinal pathophysiological changes and analyzing novel therapeutic treatments related to the energy consumption of photoreceptors.
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Affiliation(s)
- Yuttamol Muangkram
- Department of Bioinformatics, College of Life Sciences, Ritsumeikan University, Shiga, Japan.
| | - Yukiko Himeno
- Department of Bioinformatics, College of Life Sciences, Ritsumeikan University, Shiga, Japan
| | - Akira Amano
- Department of Bioinformatics, College of Life Sciences, Ritsumeikan University, Shiga, Japan
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24
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Burtscher V, Mount J, Cowgill J, Chang Y, Bickel K, Yuan P, Chanda B. Structural Basis for Hyperpolarization-dependent Opening of the Human HCN1 Channel. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.17.553623. [PMID: 37645882 PMCID: PMC10462129 DOI: 10.1101/2023.08.17.553623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
Hyperpolarization and cyclic-nucleotide (HCN) activated ion channels play a critical role in generating self-propagating action potentials in pacemaking and rhythmic electrical circuits in the human body. Unlike most voltage-gated ion channels, the HCN channels activate upon membrane hyperpolarization, but the structural mechanisms underlying this gating behavior remain unclear. Here, we present cryo-electron microscopy structures of human HCN1 in Closed, Intermediate, and Open states. Our structures reveal that the inward motion of two gating charges past the charge transfer center (CTC) and concomitant tilting of the S5 helix drives the opening of the central pore. In the intermediate state structure, a single gating charge is positioned below the CTC and the pore appears closed, whereas in the open state structure, both charges move past CTC and the pore is fully open. Remarkably, the downward motion of the voltage sensor is accompanied by progressive unwinding of the inner end of S4 and S5 helices disrupting the tight gating interface that stabilizes the Closed state structure. This "melting" transition at the intracellular gating interface leads to a concerted iris-like displacement of S5 and S6 helices, resulting in pore opening. These findings reveal key structural features that are likely to underlie reversed voltage-dependence of HCN channels.
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Affiliation(s)
- Verena Burtscher
- Department of Anesthesiology, Washington University School of Medicine, Saint Louis, MO, USA
- Center for the Investigation of Membrane Excitability Diseases, Washington University School of Medicine, Saint Louis, MO, USA
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Jonathan Mount
- Department of Cell Biology and Physiology, Washington University School of Medicine, Saint Louis, MO, USA
- Center for the Investigation of Membrane Excitability Diseases, Washington University School of Medicine, Saint Louis, MO, USA
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - John Cowgill
- Department of Anesthesiology, Washington University School of Medicine, Saint Louis, MO, USA
- Center for the Investigation of Membrane Excitability Diseases, Washington University School of Medicine, Saint Louis, MO, USA
- Department of Applied Physics, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Yongchang Chang
- Department of Anesthesiology, Washington University School of Medicine, Saint Louis, MO, USA
- Center for the Investigation of Membrane Excitability Diseases, Washington University School of Medicine, Saint Louis, MO, USA
| | - Kathleen Bickel
- Department of Anesthesiology, Washington University School of Medicine, Saint Louis, MO, USA
- Center for the Investigation of Membrane Excitability Diseases, Washington University School of Medicine, Saint Louis, MO, USA
| | - Peng Yuan
- Department of Cell Biology and Physiology, Washington University School of Medicine, Saint Louis, MO, USA
- Center for the Investigation of Membrane Excitability Diseases, Washington University School of Medicine, Saint Louis, MO, USA
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Baron Chanda
- Department of Anesthesiology, Washington University School of Medicine, Saint Louis, MO, USA
- Center for the Investigation of Membrane Excitability Diseases, Washington University School of Medicine, Saint Louis, MO, USA
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, Saint Louis, MO, USA
- Department of Neuroscience, Washington University School of Medicine, Saint Louis, MO, USA
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25
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Mangmool S, Duangrat R, Parichatikanond W, Kurose H. New Therapeutics for Heart Failure: Focusing on cGMP Signaling. Int J Mol Sci 2023; 24:12866. [PMID: 37629047 PMCID: PMC10454066 DOI: 10.3390/ijms241612866] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 07/30/2023] [Accepted: 08/08/2023] [Indexed: 08/27/2023] Open
Abstract
Current drugs for treating heart failure (HF), for example, angiotensin II receptor blockers and β-blockers, possess specific target molecules involved in the regulation of the cardiac circulatory system. However, most clinically approved drugs are effective in the treatment of HF with reduced ejection fraction (HFrEF). Novel drug classes, including angiotensin receptor blocker/neprilysin inhibitor (ARNI), sodium-glucose co-transporter-2 (SGLT2) inhibitor, hyperpolarization-activated cyclic nucleotide-gated (HCN) channel blocker, soluble guanylyl cyclase (sGC) stimulator/activator, and cardiac myosin activator, have recently been introduced for HF intervention based on their proposed novel mechanisms. SGLT2 inhibitors have been shown to be effective not only for HFrEF but also for HF with preserved ejection fraction (HFpEF). In the myocardium, excess cyclic adenosine monophosphate (cAMP) stimulation has detrimental effects on HFrEF, whereas cyclic guanosine monophosphate (cGMP) signaling inhibits cAMP-mediated responses. Thus, molecules participating in cGMP signaling are promising targets of novel drugs for HF. In this review, we summarize molecular pathways of cGMP signaling and clinical trials of emerging drug classes targeting cGMP signaling in the treatment of HF.
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Affiliation(s)
- Supachoke Mangmool
- Department of Pharmacology, Faculty of Science, Mahidol University, Bangkok 10400, Thailand; (S.M.); (R.D.)
| | - Ratchanee Duangrat
- Department of Pharmacology, Faculty of Science, Mahidol University, Bangkok 10400, Thailand; (S.M.); (R.D.)
| | | | - Hitoshi Kurose
- Pharmacology for Life Sciences, Graduate School of Pharmaceutical Sciences, Tokushima University, Tokushima 770-8505, Japan
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26
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Hu Z, Zheng X, Yang J. Conformational trajectory of allosteric gating of the human cone photoreceptor cyclic nucleotide-gated channel. Nat Commun 2023; 14:4284. [PMID: 37463923 DOI: 10.1038/s41467-023-39971-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Accepted: 07/05/2023] [Indexed: 07/20/2023] Open
Abstract
Cyclic nucleotide-gated (CNG) channels transduce chemical signals into electrical signals in sensory receptors and neurons. They are activated by cGMP or cAMP, which bind to the cyclic nucleotide-binding domain (CNBD) to open a gate located 50-60 Å away in the central cavity. Structures of closed and open vertebrate CNG channels have been solved, but the conformational landscape of this allosteric gating remains to be elucidated and enriched. Here, we report structures of the cGMP-activated human cone photoreceptor CNGA3/CNGB3 channel in closed, intermediate, pre-open and open states in detergent or lipid nanodisc, all with fully bound cGMP. The pre-open and open states are obtained only in the lipid nanodisc, suggesting a critical role of lipids in tuning the energetic landscape of CNGA3/CNGB3 activation. The different states exhibit subunit-unique, incremental and distinct conformational rearrangements that originate in the CNBD, propagate through the gating ring to the transmembrane domain, and gradually open the S6 cavity gate. Our work illustrates a spatial conformational-change wave of allosteric gating of a vertebrate CNG channel by its natural ligand and provides an expanded framework for studying CNG properties and channelopathy.
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Affiliation(s)
- Zhengshan Hu
- Department of Biological Sciences, Columbia University, New York, NY, 10027, USA
| | - Xiangdong Zheng
- Department of Biological Sciences, Columbia University, New York, NY, 10027, USA
| | - Jian Yang
- Department of Biological Sciences, Columbia University, New York, NY, 10027, USA.
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27
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Li S, Ma H, Yang F, Ding X. cGMP Signaling in Photoreceptor Degeneration. Int J Mol Sci 2023; 24:11200. [PMID: 37446378 PMCID: PMC10342299 DOI: 10.3390/ijms241311200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 07/04/2023] [Accepted: 07/05/2023] [Indexed: 07/15/2023] Open
Abstract
Photoreceptors in the retina are highly specialized neurons with photosensitive molecules in the outer segment that transform light into chemical and electrical signals, and these signals are ultimately relayed to the visual cortex in the brain to form vision. Photoreceptors are composed of rods and cones. Rods are responsible for dim light vision, whereas cones are responsible for bright light, color vision, and visual acuity. Photoreceptors undergo progressive degeneration over time in many hereditary and age-related retinal diseases. Despite the remarkable heterogeneity of disease-causing genes, environmental factors, and pathogenesis, the progressive death of rod and cone photoreceptors ultimately leads to loss of vision/blindness. There are currently no treatments available for retinal degeneration. Cyclic guanosine 3', 5'-monophosphate (cGMP) plays a pivotal role in phototransduction. cGMP governs the cyclic nucleotide-gated (CNG) channels on the plasma membrane of the photoreceptor outer segments, thereby regulating membrane potential and signal transmission. By gating the CNG channels, cGMP regulates cellular Ca2+ homeostasis and signal transduction. As a second messenger, cGMP activates the cGMP-dependent protein kinase G (PKG), which regulates numerous targets/cellular events. The dysregulation of cGMP signaling is observed in varieties of photoreceptor/retinal degenerative diseases. Abnormally elevated cGMP signaling interferes with various cellular events, which ultimately leads to photoreceptor degeneration. In line with this, strategies to reduce cellular cGMP signaling result in photoreceptor protection in mouse models of retinal degeneration. The potential mechanisms underlying cGMP signaling-induced photoreceptor degeneration involve the activation of PKG and impaired Ca2+ homeostasis/Ca2+ overload, resulting from overactivation of the CNG channels, as well as the subsequent activation of the downstream cellular stress/death pathways. Thus, targeting the cellular cGMP/PKG signaling and the Ca2+-regulating pathways represents a significant strategy for photoreceptor protection in retinal degenerative diseases.
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Affiliation(s)
| | | | | | - Xiqin Ding
- Department of Cell Biology, College of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (S.L.); (H.M.); (F.Y.)
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28
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Gerhardt MJ, Petersen-Jones SM, Michalakis S. CNG channel-related retinitis pigmentosa. Vision Res 2023; 208:108232. [PMID: 37054604 PMCID: PMC10373105 DOI: 10.1016/j.visres.2023.108232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 03/27/2023] [Accepted: 03/27/2023] [Indexed: 04/15/2023]
Abstract
The genes CNGA1 and CNGB1 encode the alpha and beta subunits of the rod CNG channel, a ligand-gated cation channel whose activity is controlled by cyclic guanosine monophosphate (cGMP). Autosomal inherited mutations in either of the genes lead to a progressive rod-cone retinopathy known as retinitis pigmentosa (RP). The rod CNG channel is expressed in the plasma membrane of the outer segment and functions as a molecular switch that converts light-mediated changes in cGMP into a voltage and Ca2+ signal. Here, we will first review the molecular properties and physiological role of the rod CNG channel and then discuss the characteristics of CNG-related RP. Finally, we will summarize recent activities in the field of gene therapy aimed at developing therapies for CNG-related RP.
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Affiliation(s)
- Maximilian J Gerhardt
- Department of Ophthalmology, University Hospital, LMU Munich, Mathildenstraße 8, 80336 München, Germany
| | - Simon M Petersen-Jones
- College of Veterinary Medicine, Michigan State University, East Lansing, MI 48824, United States
| | - Stylianos Michalakis
- Department of Ophthalmology, University Hospital, LMU Munich, Mathildenstraße 8, 80336 München, Germany.
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29
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Prelic S, Getahun MN, Kaltofen S, Hansson BS, Wicher D. Modulation of the NO-cGMP pathway has no effect on olfactory responses in the Drosophila antenna. Front Cell Neurosci 2023; 17:1180798. [PMID: 37305438 PMCID: PMC10248080 DOI: 10.3389/fncel.2023.1180798] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Accepted: 05/02/2023] [Indexed: 06/13/2023] Open
Abstract
Olfaction is a crucial sensory modality in insects and is underpinned by odor-sensitive sensory neurons expressing odorant receptors that function in the dendrites as odorant-gated ion channels. Along with expression, trafficking, and receptor complexing, the regulation of odorant receptor function is paramount to ensure the extraordinary sensory abilities of insects. However, the full extent of regulation of sensory neuron activity remains to be elucidated. For instance, our understanding of the intracellular effectors that mediate signaling pathways within antennal cells is incomplete within the context of olfaction in vivo. Here, with the use of optical and electrophysiological techniques in live antennal tissue, we investigate whether nitric oxide signaling occurs in the sensory periphery of Drosophila. To answer this, we first query antennal transcriptomic datasets to demonstrate the presence of nitric oxide signaling machinery in antennal tissue. Next, by applying various modulators of the NO-cGMP pathway in open antennal preparations, we show that olfactory responses are unaffected by a wide panel of NO-cGMP pathway inhibitors and activators over short and long timescales. We further examine the action of cAMP and cGMP, cyclic nucleotides previously linked to olfactory processes as intracellular potentiators of receptor functioning, and find that both long-term and short-term applications or microinjections of cGMP have no effect on olfactory responses in vivo as measured by calcium imaging and single sensillum recording. The absence of the effect of cGMP is shown in contrast to cAMP, which elicits increased responses when perfused shortly before olfactory responses in OSNs. Taken together, the apparent absence of nitric oxide signaling in olfactory neurons indicates that this gaseous messenger may play no role as a regulator of olfactory transduction in insects, though may play other physiological roles at the sensory periphery of the antenna.
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Affiliation(s)
- Sinisa Prelic
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Jena, Germany
| | - Merid N. Getahun
- International Centre of Insect Physiology and Ecology, Nairobi, Kenya
| | - Sabine Kaltofen
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Jena, Germany
| | - Bill S. Hansson
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Jena, Germany
| | - Dieter Wicher
- Department of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, Jena, Germany
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30
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Hiasa S, Fujimori T, Aiki S, Ueda H, Tsuboi T, Kitaguchi T. Development of green fluorescent protein-based cAMP indicators for covering a wide range of cAMP concentrations. RSC Adv 2023; 13:15514-15520. [PMID: 37223420 PMCID: PMC10201545 DOI: 10.1039/d3ra01390a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Accepted: 05/12/2023] [Indexed: 05/25/2023] Open
Abstract
There is a wide range in the concentration of intracellular cyclic adenosine 3',5'-monophosphate (cAMP), which mediates specific effects as a second messenger in pathways affecting many physiological processes. Here, we developed green fluorescent cAMP indicators, named Green Falcan (Green fluorescent protein-based indicator visualizing cAMP dynamics) with various EC50 values (0.3, 1, 3, 10 μM) for covering the wide range of intracellular cAMP concentrations. The fluorescence intensity of Green Falcans increased in a cAMP dose-dependent manner, with a dynamic range of over 3-fold. Green Falcans showed a high specificity for cAMP over its structural analogues. When we expressed Green Falcans in HeLa cells, these indicators were applicable for visualization of cAMP dynamics in the low concentration range compared to the previously developed cAMP indicators, and visualized distinct kinetics of cAMP in various pathways with high spatiotemporal resolution in living cells. Furthermore, we demonstrated that Green Falcans are applicable to dual-color imaging with R-GECO, a red fluorescent Ca2+ indicator, in the cytoplasm and the nucleus. This study shows that Green Falcans open up a new avenue for understanding hierarchal and cooperative interactions with other molecules in various cAMP signaling pathways by multi-color imaging.
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Affiliation(s)
- Sohei Hiasa
- School of Life Science and Technology, Department of Life Science and Technology, Tokyo Institute of Technology 4259 Nagatsuta-cho, Midori-ku Yokohama-shi Kanagawa 226-8501 Japan
| | - Takeru Fujimori
- School of Life Science and Technology, Department of Life Science and Technology, Tokyo Institute of Technology 4259 Nagatsuta-cho, Midori-ku Yokohama-shi Kanagawa 226-8501 Japan
| | - Saki Aiki
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo 3-8-1 Komaba, Meguro-ku Tokyo 153-8902 Japan
| | - Hiroshi Ueda
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology 4259 Nagatsuta-cho, Midori-ku Yokohama-shi Kanagawa 226-8503 Japan
| | - Takashi Tsuboi
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo 3-8-1 Komaba, Meguro-ku Tokyo 153-8902 Japan
| | - Tetsuya Kitaguchi
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology 4259 Nagatsuta-cho, Midori-ku Yokohama-shi Kanagawa 226-8503 Japan
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31
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Justo AFO, Toscano ECDB, Farias-Itao DS, Suemoto CK. The action of phosphodiesterase-5 inhibitors on β-amyloid pathology and cognition in experimental Alzheimer's disease: A systematic review. Life Sci 2023; 320:121570. [PMID: 36921685 DOI: 10.1016/j.lfs.2023.121570] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 02/09/2023] [Accepted: 03/08/2023] [Indexed: 03/14/2023]
Abstract
Alzheimer's disease (AD) is the most frequent cause of dementia worldwide. The etiology of AD is partially explained by the deposition of β-amyloid in the brain. Despite extensive research on the pathogenesis of AD, the current treatments are ineffective. Here, we systematically reviewed studies that investigated whether phosphodiesterase 5 inhibitors (PDE5i) are efficient in reducing the β-amyloid load in hippocampi and improving cognitive decline in rodent models with β-amyloid accumulation. We identified ten original studies, which used rodent models with β-amyloid accumulation, were treated with PDE5i, and β-amyloid was measured in the hippocampi. PDE5i was efficient in reducing the β-amyloid levels, except for one study that exclusively used female rodents and the treatment did not affect β-amyloid levels. Interestingly, PDE5i prevented cognitive decline in all studies. This study supports the potential therapeutic use of PDE5i for the reduction of the β-amyloid load in hippocampi and cognitive decline. However, we highlight the importance of conducting additional experimental studies to evaluate the PDE5i-related molecular mechanisms involved in β-amyloid removal in male and female animals.
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Affiliation(s)
- Alberto Fernando Oliveira Justo
- Physiopathology in Aging Laboratory (LIM-22), Department of Internal Medicine, University of São Paulo Medical School, São Paulo, Brazil.
| | - Eliana Cristina de Brito Toscano
- Physiopathology in Aging Laboratory (LIM-22), Department of Internal Medicine, University of São Paulo Medical School, São Paulo, Brazil; Department of Pathology, Federal University of Juiz de Fora Medical School, Juiz de Fora, Brazil; Post-graduation Program in Health, Federal University of Juiz de Fora Medical School, Juiz de Fora, Brazil.
| | | | - Claudia Kimie Suemoto
- Physiopathology in Aging Laboratory (LIM-22), Department of Internal Medicine, University of São Paulo Medical School, São Paulo, Brazil; Division of Geriatrics, Department of Internal Medicine, University of São Paulo Medical School, São Paulo, Brazil.
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32
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Andersson J, Kleinheinz D, Ramach U, Kiesenhofer N, Ashenden A, Valtiner M, Holt S, Koeper I, Schmidpeter PAM, Knoll W. Native Function of the Bacterial Ion Channel SthK in a Sparsely Tethered Lipid Bilayer Membrane Architecture. J Phys Chem B 2023; 127:3641-3650. [PMID: 37072125 PMCID: PMC10150356 DOI: 10.1021/acs.jpcb.2c07252] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/20/2023]
Abstract
The plasma membrane protects the interiors of cells from their surroundings and also plays a critical role in communication, sensing, and nutrient import. As a result, the cell membrane and its constituents are among the most important drug targets. Studying the cell membrane and the processes it facilitates is therefore crucial, but it is a highly complex environment that is difficult to access experimentally. Various model membrane systems have been developed to provide an environment in which membrane proteins can be studied in isolation. Among them, tethered bilayer lipid membranes (tBLMs) are a promising model system providing a solvent-free membrane environment which can be prepared by self-assembly, is resistant to mechanical disturbances and has a high electrical resistance. tBLMs are therefore uniquely suitable to study ion channels and charge transport processes. However, ion channels are often large, complex, multimeric structures and their function requires a particular lipid environment. In this paper, we show that SthK, a bacterial cyclic nucleotide gated (CNG) ion channel that is strongly dependent on the surrounding lipid composition, functions normally when embedded into a sparsely tethered lipid bilayer. As SthK has been very well characterized in terms of structure and function, it is well-suited to demonstrate the utility of tethered membrane systems. A model membrane system suitable for studying CNG ion channels would be useful, as this type of ion channel performs a wide range of physiological functions in bacteria, plants, and mammals and is therefore of fundamental scientific interest as well as being highly relevant to medicine.
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Affiliation(s)
- Jakob Andersson
- Austrian Institute of Technology GmbH, Giefinggasse 4, 1210 Vienna, Austria
| | - David Kleinheinz
- Austrian Institute of Technology GmbH, Giefinggasse 4, 1210 Vienna, Austria
| | - Ulrich Ramach
- Technische Universität Wien, Wiedner Hauptstr. 8-10/134, 1040 Wien, Austria
- CEST Kompetenzzentrum für Oberflächentechnologie, Viktor Kaplan-Straße 2, 2700 Wiener Neustadt, Austria
| | | | - Alex Ashenden
- Flinders University of South Australia, Bedford Park SA, 5042 Adelaide, Australia
| | - Markus Valtiner
- Technische Universität Wien, Wiedner Hauptstr. 8-10/134, 1040 Wien, Austria
- CEST Kompetenzzentrum für Oberflächentechnologie, Viktor Kaplan-Straße 2, 2700 Wiener Neustadt, Austria
| | - Stephen Holt
- Australian Nuclear Science and Technology Organization, New Illawarra Rd, Lucas Heights, NSW 2234, Australia
| | - Ingo Koeper
- Flinders University of South Australia, Bedford Park SA, 5042 Adelaide, Australia
| | - Philipp A M Schmidpeter
- Weill Cornell Medicine, Department of Anesthesiology, 1300 York Avenue, New York, New York 10065, United States
| | - Wolfgang Knoll
- Austrian Institute of Technology GmbH, Giefinggasse 4, 1210 Vienna, Austria
- Danube Private University, Steiner Landstraße 124, 3500 Krems an der Donau, Austria
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33
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Slika H, Mansour H, Nasser SA, Shaito A, Kobeissy F, Orekhov AN, Pintus G, Eid AH. Epac as a tractable therapeutic target. Eur J Pharmacol 2023; 945:175645. [PMID: 36894048 DOI: 10.1016/j.ejphar.2023.175645] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2022] [Revised: 02/26/2023] [Accepted: 03/06/2023] [Indexed: 03/09/2023]
Abstract
In 1957, cyclic adenosine monophosphate (cAMP) was identified as the first secondary messenger, and the first signaling cascade discovered was the cAMP-protein kinase A (PKA) pathway. Since then, cAMP has received increasing attention given its multitude of actions. Not long ago, a new cAMP effector named exchange protein directly activated by cAMP (Epac) emerged as a critical mediator of cAMP's actions. Epac mediates a plethora of pathophysiologic processes and contributes to the pathogenesis of several diseases such as cancer, cardiovascular disease, diabetes, lung fibrosis, neurological disorders, and others. These findings strongly underscore the potential of Epac as a tractable therapeutic target. In this context, Epac modulators seem to possess unique characteristics and advantages and hold the promise of providing more efficacious treatments for a wide array of diseases. This paper provides an in-depth dissection and analysis of Epac structure, distribution, subcellular compartmentalization, and signaling mechanisms. We elaborate on how these characteristics can be utilized to design specific, efficient, and safe Epac agonists and antagonists that can be incorporated into future pharmacotherapeutics. In addition, we provide a detailed portfolio for specific Epac modulators highlighting their discovery, advantages, potential concerns, and utilization in the context of clinical disease entities.
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Affiliation(s)
- Hasan Slika
- Department of Pharmacology and Toxicology, American University of Beirut, Beirut, P.O. Box 11-0236, Lebanon.
| | - Hadi Mansour
- Department of Pharmacology and Toxicology, American University of Beirut, Beirut, P.O. Box 11-0236, Lebanon.
| | | | - Abdullah Shaito
- Biomedical Research Center, Qatar University, Doha, P.O. Box: 2713, Qatar.
| | - Firas Kobeissy
- Department of Neurobiology and Neuroscience, Morehouse School of Medicine, Atlanta, Georgia, USA.
| | - Alexander N Orekhov
- Laboratory of Cellular and Molecular Pathology of Cardiovascular System, Institute of Human Morphology, 3 Tsyurupa Street, Moscow, 117418, Russia; Laboratory of Angiopathology, Institute of General Pathology and Pathophysiology, 8 Baltiiskaya Street, Moscow, 125315, Russia; Institute for Atherosclerosis Research, Skolkovo Innovative Center, Osennyaya Street 4-1-207, Moscow, 121609, Russia.
| | - Gianfranco Pintus
- Department of Biomedical Sciences, University of Sassari, 07100, Sassari, Italy.
| | - Ali H Eid
- Department of Basic Medical Sciences, College of Medicine, QU Health, Qatar University, Doha, P.O. Box 2713, Qatar.
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Barret D, Schuster D, Rodrigues M, Leitner A, Picotti P, Schertler G, Kaupp U, Korkhov V, Marino J. Structural basis of calmodulin modulation of the rod cyclic nucleotide-gated channel. Proc Natl Acad Sci U S A 2023; 120:e2300309120. [PMID: 37011209 PMCID: PMC10104587 DOI: 10.1073/pnas.2300309120] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2023] [Accepted: 03/06/2023] [Indexed: 04/05/2023] Open
Abstract
Calmodulin (CaM) regulates many ion channels to control calcium entry into cells, and mutations that alter this interaction are linked to fatal diseases. The structural basis of CaM regulation remains largely unexplored. In retinal photoreceptors, CaM binds to the CNGB subunit of cyclic nucleotide-gated (CNG) channels and, thereby, adjusts the channel's Cyclic guanosine monophosphate (cGMP) sensitivity in response to changes in ambient light conditions. Here, we provide the structural characterization for CaM regulation of a CNG channel by using a combination of single-particle cryo-electron microscopy and structural proteomics. CaM connects the CNGA and CNGB subunits, resulting in structural changes both in the cytosolic and transmembrane regions of the channel. Cross-linking and limited proteolysis-coupled mass spectrometry mapped the conformational changes induced by CaM in vitro and in the native membrane. We propose that CaM is a constitutive subunit of the rod channel to ensure high sensitivity in dim light. Our mass spectrometry-based approach is generally relevant for studying the effect of CaM on ion channels in tissues of medical interest, where only minute quantities are available.
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Affiliation(s)
- Diane C. A. Barret
- Laboratory of Biomolecular Research, Paul Scherrer Institute, 5232Villigen, Switzerland
| | - Dina Schuster
- Laboratory of Biomolecular Research, Paul Scherrer Institute, 5232Villigen, Switzerland
- Institute of Molecular Systems Biology, Department of Biology, ETH Zurich, 8049Zürich, Switzerland
- Institute of Molecular Biology and Biophysics, ETH Zürich, 8049Zurich, Switzerland
| | - Matthew J. Rodrigues
- Laboratory of Biomolecular Research, Paul Scherrer Institute, 5232Villigen, Switzerland
| | - Alexander Leitner
- Institute of Molecular Systems Biology, Department of Biology, ETH Zurich, 8049Zürich, Switzerland
| | - Paola Picotti
- Institute of Molecular Systems Biology, Department of Biology, ETH Zurich, 8049Zürich, Switzerland
| | | | - U. Benjamin Kaupp
- Life and Medical Sciences Institute, University of Bonn, 53115Bonn, Germany
- Max Planck Institute for Multidisciplinary Sciences, 37077Göttingen, Germany
| | - Volodymyr M. Korkhov
- Laboratory of Biomolecular Research, Paul Scherrer Institute, 5232Villigen, Switzerland
- Institute of Molecular Biology and Biophysics, ETH Zürich, 8049Zurich, Switzerland
| | - Jacopo Marino
- Laboratory of Biomolecular Research, Paul Scherrer Institute, 5232Villigen, Switzerland
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35
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Takeuchi H, Kurahashi T. Segregation of Ca2+ signaling in olfactory signal transduction. J Gen Physiol 2023; 155:213865. [PMID: 36787110 PMCID: PMC9960254 DOI: 10.1085/jgp.202213165] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 11/04/2022] [Accepted: 01/13/2023] [Indexed: 02/15/2023] Open
Abstract
Olfactory signal transduction is conducted through a cAMP-mediated second messenger cascade. The cytoplasmic Ca2+ concentration increases through the opening of CNG channels, a phenomenon that underlies two major functions, namely, signal boosting and olfactory adaptation. Signal boosting is achieved by an additional opening of the Ca2+-activated Cl- channel whereas adaptation is regulated by Ca2+ feedback to the CNG channel. Thus, the influx of Ca2+ and the resultant increase in cytoplasmic Ca2+ levels play seemingly opposing effects: increasing the current while reducing the current through adaptation. The two functions could be interpreted as compensating for each other. However, in real cells, both functions should be segregated. Ca2+ dynamics in olfactory cilia need to be directly measured, but technical difficulties accompanying the thin structure of olfactory cilia have prevented systematic analyses. In this study, using a combination of electrophysiology, local photolysis of caged cAMP, and Ca2+ imaging, we found that free Ca2+ in the local ciliary cytoplasm decreased along with a reduction in the current containing Ca2+-activated Cl- components returning to the basal level, whereas Ca2+-dependent adaptation persisted for a longer period. The activity of Cl- channels is highly likely to be regulated by the free Ca2+ that is present only immediately after the influx through the CNG channel, and an exclusive interaction between Ca2+ and Ca2+-binding proteins that mediate the adaptation may modulate the adaptation lifetime.
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Affiliation(s)
- Hiroko Takeuchi
- Department of Biophysical Dynamics, Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
- Correspondence to Hiroko Takeuchi:
| | - Takashi Kurahashi
- Department of Biophysical Dynamics, Graduate School of Frontier Biosciences, Osaka University, Osaka, Japan
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36
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Geada S, Teixeira-Marques F, Teixeira B, Carvalho AL, Lousan N, Saraiva J, Murta J, Silva R, Zanlonghi X, Defoort-Dhellemmes S, Smirnov V, Dhaenens CM, Blanchet C, Meunier I, Marques JP. Mutational Spectrum, Ocular and Olfactory Phenotypes of CNGB1-Related RP-Olfactory Dysfunction Syndrome in a Multiethnic Cohort. Genes (Basel) 2023; 14:genes14040830. [PMID: 37107588 PMCID: PMC10137467 DOI: 10.3390/genes14040830] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2023] [Revised: 03/17/2023] [Accepted: 03/26/2023] [Indexed: 04/29/2023] Open
Abstract
CNGB1 gene mutations are a well-known cause of autosomal recessive retinitis pigmentosa (RP), which was recently associated with olfactory dysfunction. The purpose of this study was to report the molecular spectrum and the ocular and olfactory phenotypes of a multiethnic cohort with CNGB1-associated RP. A cross-sectional case series was conducted at two ophthalmic genetics referral centers. Consecutive patients with molecularly confirmed CNGB1-related RP were included. All patients underwent a complete ophthalmological examination complemented by psychophysical olfactory evaluation. Fifteen patients (10 families: 8 Portuguese, 1 French, and 1 Turkish), mean aged 57.13 ± 15.37 years old (yo), were enrolled. Seven disease-causing variants were identified, two of which are reported for the first time: c.2565_2566del and c.2285G > T. Although 11/15 patients reported onset of nyctalopia before age 10, diagnosis was only established after 30 yo in 9/15. Despite widespread retinal degeneration being present in 14/15 probands, a relatively preserved visual acuity was observed throughout follow-up. Olfactory function was preserved in only 4/15 patients, all of whom carried at least one missense variant. Our study supports previous reports of an autosomal recessive RP-olfactory dysfunction syndrome in association with certain disease-causing variants in the CNGB1 gene and expands the mutational spectrum of CNGB1-related disease by reporting two novel variants.
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Affiliation(s)
- Sara Geada
- Ophthalmology Unit, Centro Hospitalar e Universitário de Coimbra (CHUC), 3000-075 Coimbra, Portugal
| | - Francisco Teixeira-Marques
- Department of Otorhinolaryngology, Centro Hospitalar do Tâmega e Sousa (CHTS), 4560-162 Penafiel, Portugal
| | - Bruno Teixeira
- Ophthalmology Unit, Centro Hospitalar e Universitário de Coimbra (CHUC), 3000-075 Coimbra, Portugal
| | - Ana Luísa Carvalho
- Medical Genetics Unit, Centro Hospitalar e Universitário de Coimbra, 3000-602 Coimbra, Portugal
- Clinical Academic Center of Coimbra (CACC), 3000-354 Coimbra, Portugal
- University Clinic of Medical Genetics, Faculty of Medicine, University of Coimbra (FMUC), 3000-354 Coimbra, Portugal
- University Clinic of Pediatrics, Faculty of Medicine, University of Coimbra (FMUC), 3000-354 Coimbra, Portugal
| | - Nuno Lousan
- Department of Otorhinolaryngology, Centro Hospitalar do Tâmega e Sousa (CHTS), 4560-162 Penafiel, Portugal
| | - Jorge Saraiva
- Medical Genetics Unit, Centro Hospitalar e Universitário de Coimbra, 3000-602 Coimbra, Portugal
- Clinical Academic Center of Coimbra (CACC), 3000-354 Coimbra, Portugal
- University Clinic of Medical Genetics, Faculty of Medicine, University of Coimbra (FMUC), 3000-354 Coimbra, Portugal
- University Clinic of Pediatrics, Faculty of Medicine, University of Coimbra (FMUC), 3000-354 Coimbra, Portugal
| | - Joaquim Murta
- Ophthalmology Unit, Centro Hospitalar e Universitário de Coimbra (CHUC), 3000-075 Coimbra, Portugal
- Clinical Academic Center of Coimbra (CACC), 3000-354 Coimbra, Portugal
- University Clinic of Ophthalmology, Faculty of Medicine, University of Coimbra (FMUC), 3000-354 Coimbra, Portugal
| | - Rufino Silva
- Ophthalmology Unit, Centro Hospitalar e Universitário de Coimbra (CHUC), 3000-075 Coimbra, Portugal
- Clinical Academic Center of Coimbra (CACC), 3000-354 Coimbra, Portugal
- University Clinic of Ophthalmology, Faculty of Medicine, University of Coimbra (FMUC), 3000-354 Coimbra, Portugal
| | - Xavier Zanlonghi
- Eye Department, Rennes University Hospital, 35 033 Rennes, France
| | - Sabine Defoort-Dhellemmes
- Department of Visual Exploration and Neuro-Ophthalmology, Robert Salengro Hospital, 59 037 Lille, France
- Sensgene Care Network, 67 091 Strasbourg, France
| | - Vasily Smirnov
- Department of Visual Exploration and Neuro-Ophthalmology, Robert Salengro Hospital, 59 037 Lille, France
- Sensgene Care Network, 67 091 Strasbourg, France
| | - Claire-Marie Dhaenens
- University of Lille, INSERM, CHU Lille, U1172-LilNCog-Lille Neuroscience & Cognition, 59 000 Lille, France
| | - Catherine Blanchet
- Reference Centre for Inherited Sensory Diseases, Montpellier University Hospital, 34 295 Montpellier, France
| | - Isabelle Meunier
- Sensgene Care Network, 67 091 Strasbourg, France
- Reference Centre for Inherited Sensory Diseases, Montpellier University Hospital, 34 295 Montpellier, France
- Institute for Neurosciences of Montpellier (INM), University of Montpellier, INSERM, 34 091 Montpellier, France
| | - João Pedro Marques
- Ophthalmology Unit, Centro Hospitalar e Universitário de Coimbra (CHUC), 3000-075 Coimbra, Portugal
- Clinical Academic Center of Coimbra (CACC), 3000-354 Coimbra, Portugal
- University Clinic of Ophthalmology, Faculty of Medicine, University of Coimbra (FMUC), 3000-354 Coimbra, Portugal
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Pan Y, Pohjolainen E, Schmidpeter PAM, Vaiana AC, Nimigean CM, Grubmüller H, Scheuring S. Discrimination between cyclic nucleotides in a cyclic nucleotide-gated ion channel. Nat Struct Mol Biol 2023; 30:512-520. [PMID: 36973509 DOI: 10.1038/s41594-023-00955-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2022] [Accepted: 02/24/2023] [Indexed: 03/29/2023]
Abstract
Cyclic nucleotide-gated ion channels are crucial in many physiological processes such as vision and pacemaking in the heart. SthK is a prokaryotic homolog with high sequence and structure similarities to hyperpolarization-activated and cyclic nucleotide-modulated and cyclic nucleotide-gated channels, especially at the level of the cyclic nucleotide binding domains (CNBDs). Functional measurements showed that cyclic adenosine monophosphate (cAMP) is a channel activator while cyclic guanosine monophosphate (cGMP) barely leads to pore opening. Here, using atomic force microscopy single-molecule force spectroscopy and force probe molecular dynamics simulations, we unravel quantitatively and at the atomic level how CNBDs discriminate between cyclic nucleotides. We find that cAMP binds to the SthK CNBD slightly stronger than cGMP and accesses a deep-bound state that a cGMP-bound CNBD cannot reach. We propose that the deep binding of cAMP is the discriminatory state that is essential for cAMP-dependent channel activation.
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Affiliation(s)
- Yangang Pan
- Department of Anesthesiology, Weill Cornell Medicine, New York, NY, USA
| | - Emmi Pohjolainen
- Max Planck Institute for Multidisciplinary Sciences, Theoretical and Computational Biophysics Department, Goettingen, Germany
| | | | - Andrea C Vaiana
- Max Planck Institute for Multidisciplinary Sciences, Theoretical and Computational Biophysics Department, Goettingen, Germany
- Institute of Biophysics, National Research Council, Palermo, Italy
| | - Crina M Nimigean
- Department of Anesthesiology, Weill Cornell Medicine, New York, NY, USA
- Department of Physiology and Biophysics, Weill Cornell Medicine, New York, NY, USA
| | - Helmut Grubmüller
- Max Planck Institute for Multidisciplinary Sciences, Theoretical and Computational Biophysics Department, Goettingen, Germany
| | - Simon Scheuring
- Department of Anesthesiology, Weill Cornell Medicine, New York, NY, USA.
- Department of Physiology and Biophysics, Weill Cornell Medicine, New York, NY, USA.
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38
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Henderson SW, Nakayama Y, Whitelaw ML, Bruning JB, Anderson PA, Tyerman SD, Ramesh SA, Martinac B, Yool AJ. Proteoliposomes reconstituted with human aquaporin-1 reveal novel single-ion-channel properties. BIOPHYSICAL REPORTS 2023; 3:100100. [PMID: 36949749 PMCID: PMC10025285 DOI: 10.1016/j.bpr.2023.100100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2022] [Accepted: 01/11/2023] [Indexed: 01/15/2023]
Abstract
Human aquaporin 1 (hAQP1) forms homotetrameric channels that facilitate fluxes of water and small solutes across cell membranes. In addition to water channel activity, hAQP1 displays non-selective monovalent cation-channel activity gated by intracellular cyclic GMP. Dual water and ion-channel activity of hAQP1, thought to regulate cell shape and volume, could offer a target for novel therapeutics relevant to controlling cancer cell invasiveness. This study probed properties of hAQP1 ion channels using proteoliposomes, which, unlike conventional cell-based systems such as Xenopus laevis oocytes, are relatively free of background ion channels. Histidine-tagged recombinant hAQP1 protein was synthesized and purified from the methylotrophic yeast, Pichia pastoris, and reconstituted into proteoliposomes for biophysical analyses. Osmotic water channel activity confirmed correct folding and channel assembly. Ion-channel activity of hAQP1-Myc-His6 was recorded by patch-clamp electrophysiology with excised patches. In symmetrical potassium, the hAQP1-Myc-His6 channels displayed coordinated gating, a single-channel conductance of approximately 75 pS, and multiple subconductance states. Applicability of this method for structure-function analyses was tested using hAQP1-Myc-His6 D48A/D185A channels modified by site-directed mutations of charged Asp residues estimated to be adjacent to the central ion-conducting pore of the tetramer. No differences in conductance were detected between mutant and wild-type constructs, suggesting the open-state conformation could differ substantially from expectations based on crystal structures. Nonetheless, the method pioneered here for AQP1 demonstrates feasibility for future work defining structure-function relationships, screening pharmacological inhibitors, and testing other classes in the broad family of aquaporins for previously undiscovered ion-conducting capabilities.
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Affiliation(s)
- Sam W. Henderson
- School of Biomedicine, University of Adelaide, Adelaide, SA 5005, Australia
| | - Yoshitaka Nakayama
- Victor Chang Cardiac Research Institute, Lowy Packer Building, Darlinghurst, NSW 2010, Australia
- School of Clinical Medicine, UNSW Medicine & Health, St Vincent’s Healthcare Clinical Campus, Faculty of Medicine and Health, University of New South Wales, Sydney, NSW Australia
| | - Murray L. Whitelaw
- Institute of Photonics and Advanced Sensing, The School of Biological Sciences, University of Adelaide, Adelaide, SA 5005, Australia
| | - John B. Bruning
- Institute of Photonics and Advanced Sensing, The School of Biological Sciences, University of Adelaide, Adelaide, SA 5005, Australia
| | - Peter A. Anderson
- School of Biological Sciences, Faculty of Science and Engineering, Flinders University, Adelaide, SA 5001, Australia
| | - Stephen D. Tyerman
- ARC Centre of Excellence in Plant Energy Biology, School of Agriculture, Food and Wine & Waite Research Institute, University of Adelaide, Glen Osmond, SA 5064, Australia
| | - Sunita A. Ramesh
- School of Biological Sciences, Faculty of Science and Engineering, Flinders University, Adelaide, SA 5001, Australia
| | - Boris Martinac
- Victor Chang Cardiac Research Institute, Lowy Packer Building, Darlinghurst, NSW 2010, Australia
- School of Clinical Medicine, UNSW Medicine & Health, St Vincent’s Healthcare Clinical Campus, Faculty of Medicine and Health, University of New South Wales, Sydney, NSW Australia
| | - Andrea J. Yool
- School of Biomedicine, University of Adelaide, Adelaide, SA 5005, Australia
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Biology, Pathobiology and Gene Therapy of CNG Channel-Related Retinopathies. Biomedicines 2023; 11:biomedicines11020269. [PMID: 36830806 PMCID: PMC9953513 DOI: 10.3390/biomedicines11020269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2023] [Revised: 01/16/2023] [Accepted: 01/17/2023] [Indexed: 01/21/2023] Open
Abstract
The visual process begins with the absorption of photons by photopigments of cone and rod photoreceptors in the retina. In this process, the signal is first amplified by a cyclic guanosine monophosphate (cGMP)-based signaling cascade and then converted into an electrical signal by cyclic nucleotide-gated (CNG) channels. CNG channels are purely ligand-gated channels whose activity can be controlled by cGMP, which induces a depolarizing Na+/Ca2+ current upon binding to the channel. Structurally, CNG channels belong to the superfamily of pore-loop cation channels and share structural similarities with hyperpolarization-activated cyclic nucleotide (HCN) and voltage-gated potassium (KCN) channels. Cone and rod photoreceptors express distinct CNG channels encoded by homologous genes. Mutations in the genes encoding the rod CNG channel (CNGA1 and CNGB1) result in retinitis-pigmentosa-type blindness. Mutations in the genes encoding the cone CNG channel (CNGA3 and CNGB3) lead to achromatopsia. Here, we review the molecular properties of CNG channels and describe their physiological and pathophysiological roles in the retina. Moreover, we summarize recent activities in the field of gene therapy aimed at developing the first gene therapies for CNG channelopathies.
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40
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Tan YQ, Yang Y, Shen X, Zhu M, Shen J, Zhang W, Hu H, Wang YF. Multiple cyclic nucleotide-gated channels function as ABA-activated Ca2+ channels required for ABA-induced stomatal closure in Arabidopsis. THE PLANT CELL 2023; 35:239-259. [PMID: 36069643 PMCID: PMC9806652 DOI: 10.1093/plcell/koac274] [Citation(s) in RCA: 18] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Accepted: 08/28/2022] [Indexed: 06/15/2023]
Abstract
Abscisic acid (ABA)-activated inward Ca2+-permeable channels in the plasma membrane (PM) of guard cells are required for the initiation and regulation of ABA-specific cytosolic Ca2+ signaling and stomatal closure in plants. But the identities of the PM Ca2+ channels are still unknown. We hypothesized that the ABA-activated Ca2+ channels consist of multiple CYCLIC NUCLEOTIDE-GATED CHANNEL (CNGC) proteins from the CNGC family, which is known as a Ca2+-permeable channel family in Arabidopsis (Arabidopsis thaliana). In this research, we observed high expression of multiple CNGC genes in Arabidopsis guard cells, namely CNGC5, CNGC6, CNGC9, and CNGC12. The T-DNA insertional loss-of-function quadruple mutant cngc5-1 cngc6-2 cngc9-1 cngc12-1 (hereafter c5/6/9/12) showed a strong ABA-insensitive phenotype of stomatal closure. Further analysis revealed that ABA-activated Ca2+ channel currents were impaired, and ABA-specific cytosolic Ca2+ oscillation patterns were disrupted in c5/6/9/12 guard cells compared with in wild-type guard cells. All ABA-related phenotypes of the c5/6/9/12 mutant were successfully rescued by the expression of a single gene out of the four CNGCs under the respective native promoter. Thus, our findings reveal a type of ABA-activated PM Ca2+ channel comprising multiple CNGCs, which is essential for ABA-specific Ca2+ signaling of guard cells and ABA-induced stomatal closure in Arabidopsis.
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Affiliation(s)
- Yan-Qiu Tan
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
| | - Yang Yang
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
- University of Chinese Academy of Sciences, Shanghai 200032, China
| | - Xin Shen
- National Key Laboratory of Crop Genetic Improvement, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Meijun Zhu
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
- University of Chinese Academy of Sciences, Shanghai 200032, China
| | - Jianlin Shen
- Key Laboratory of Plant Development and Environmental Adaption Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, Shandong 266237, China
| | - Wei Zhang
- Key Laboratory of Plant Development and Environmental Adaption Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, Shandong 266237, China
| | - Honghong Hu
- National Key Laboratory of Crop Genetic Improvement, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Yong-Fei Wang
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
- University of Chinese Academy of Sciences, Shanghai 200032, China
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41
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Inamdar SM, Lankford CK, Baker SA. Photoreceptor Ion Channels in Signaling and Disease. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1415:269-276. [PMID: 37440044 DOI: 10.1007/978-3-031-27681-1_39] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/14/2023]
Abstract
Photoreceptors (PRs) in the neural retina convert photon capture into an electrical signal that is communicated across a chemical synapse to second-order neurons in the retina and on through the rest of the visual pathway. This information is decoded in the visual cortex to create images. The activity of PRs depends on the concerted action of several voltage-gated ion channels that will be discussed in this chapter.
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Affiliation(s)
- Shivangi M Inamdar
- Department of Biochemistry and Molecular Biology, University of Iowa, Iowa City, IA, USA.
| | - Colten K Lankford
- Department of Biochemistry and Molecular Biology, University of Iowa, Iowa City, IA, USA
| | - Sheila A Baker
- Department of Biochemistry and Molecular Biology, University of Iowa, Iowa City, IA, USA
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42
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Dickson EJ. Role of Lysosomal Cholesterol in Regulating PI(4,5)P 2-Dependent Ion Channel Function. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1422:193-215. [PMID: 36988882 DOI: 10.1007/978-3-031-21547-6_7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 03/30/2023]
Abstract
Lysosomes are central regulators of cellular growth and signaling. Once considered the acidic garbage can of the cell, their ever-expanding repertoire of functions include the regulation of cell growth, gene regulation, metabolic signaling, cell migration, and cell death. In this chapter, we detail how another of the lysosome's crucial roles, cholesterol transport, plays a vital role in the control of ion channel function and neuronal excitability through its ability to influence the abundance of the plasma membrane signaling lipid phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2). This chapter will introduce the biosynthetic pathways of cholesterol and PI(4,5)P2, discuss the molecular mechanisms through which each lipid distinctly regulates ion channels, and consider the interdependence of these lipids in the control of ion channel function.
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Affiliation(s)
- Eamonn J Dickson
- Department of Physiology and Membrane Biology, University of California, Davis, CA, USA.
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43
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Abstract
PURPOSE Mutations in the cyclic nucleotide-gated (CNG) channel beta subunit (CNGB1) are an important cause of recessive retinitis pigmentosa. We identified a large animal model with a truncating mutation of CNGB1. This study reports the persistence of small, desensitized rod ERG responses in this model. METHODS Dark-, light-adapted and chromatic ERGs were recorded in CNGB1 mutant dogs and age and breed matched controls. Comparisons were made with a dog model known to completely lack rod function; young dogs with a mutation in the rod phosphodiesterase 6 alpha subunit (PDE6A-/-). Immunohistochemistry (IHC) to label the rod CNG alpha (CNGA1) and CNGB1 subunits was performed. RESULTS The dark-adapted ERG of CNGB1 mutant dogs had a raised response threshold with lack of normal rod response and a remaining cone response. Increasing stimulus strength resulted in the appearance of a separate, slower positive waveform following the dark-adapted cone b-wave. With increasing stimulus strength this increased in amplitude and became faster to merge with the initial b-wave. Comparison of responses from PDE6A-/- (cone only dogs) with CNGB1 mutant dogs to red and blue flashes and between dark-adapted and light-adapted responses supported the hypothesis that the CNGB1 mutant dog had residual desensitized rod responses. CNGB1 mutant dogs had a small amount of CNGA1 detectable in the outer segments. CONCLUSIONS CNGB1 mutant dogs have a residual ERG response from desensitized rods. This may be due to low levels of CNGA1 in outer segments.
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44
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Tropea MR, Gulisano W, Vacanti V, Arancio O, Puzzo D, Palmeri A. Nitric oxide/cGMP/CREB pathway and amyloid-beta crosstalk: From physiology to Alzheimer's disease. Free Radic Biol Med 2022; 193:657-668. [PMID: 36400326 DOI: 10.1016/j.freeradbiomed.2022.11.022] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 10/30/2022] [Accepted: 11/12/2022] [Indexed: 11/17/2022]
Abstract
The nitric oxide (NO)/cGMP pathway has been extensively studied for its pivotal role in synaptic plasticity and memory processes, resulting in an increase of cAMP response element-binding (CREB) phosphorylation, and consequent synthesis of plasticity-related proteins. The NO/cGMP/CREB signaling is downregulated during aging and neurodegenerative disorders and is affected by Amyloid-β peptide (Aβ) and tau protein, whose increase and deposition is considered the key pathogenic event of Alzheimer's disease (AD). On the other hand, in physiological conditions, the crosstalk between the NO/cGMP/PKG/CREB pathway and Aβ ensures long-term potentiation and memory formation. This review summarizes the current knowledge on the interaction between the NO/cGMP/PKG/CREB pathway and Aβ in the healthy and diseased brain, offering a new perspective to shed light on AD pathophysiology. We will focus on the synaptic mechanisms underlying Aβ physiological interplay with cGMP pathway and how this balance is corrupted in AD, as high levels of Aβ interfere with NO production and cGMP molecular signaling leading to cognitive impairment. Finally, we will discuss results from preclinical and clinical studies proposing the increase of cGMP signaling as a therapeutic strategy in the treatment of AD.
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Affiliation(s)
- Maria Rosaria Tropea
- Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, 95123, Italy
| | - Walter Gulisano
- Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, 95123, Italy
| | - Valeria Vacanti
- Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, 95123, Italy
| | - Ottavio Arancio
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, USA; Department of Pathology & Cell Biology and Department of Medicine, Columbia University, New York, NY, 10032, USA
| | - Daniela Puzzo
- Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, 95123, Italy; Oasi Research Institute-IRCCS, Troina (EN), 94018, Italy.
| | - Agostino Palmeri
- Department of Biomedical and Biotechnological Sciences, University of Catania, Catania, 95123, Italy
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Lee SK, Lee SM, Kim MH, Park SK, Jung KH. Genome-Wide Analysis of Cyclic Nucleotide-Gated Channel Genes Related to Pollen Development in Rice. PLANTS (BASEL, SWITZERLAND) 2022; 11:plants11223145. [PMID: 36432876 PMCID: PMC9692566 DOI: 10.3390/plants11223145] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 10/06/2022] [Accepted: 11/11/2022] [Indexed: 05/31/2023]
Abstract
In the angiosperm, pollen germinates and rapidly expands the pollen tube toward the ovule. This process is important for plant double fertilization and seed setting. It is well known that the tip-focused calcium gradient is essential for pollen germination and pollen tube growth. However, little is known about the Ca2+ channels that play a role in rice pollen germination and tube growth. Here, we divided the 16 cyclic nucleotide-gated channel (CNGC) genes from rice into five subgroups and found two subgroups (clades II and III) have pollen-preferential genes. Then, we performed a meta-expression analysis of all OsCNGC genes in anatomical samples and identified three pollen-preferred OsCNGCs (OsCNGC4, OsCNGC5, and OsCNGC8). The subcellular localization of these OsCNGC proteins is matched with their roles as ion channels on the plasma membrane. Unlike other OsCNGCs, these genes have a unique cis-acting element in the promoter. OsCNGC4 can act by forming a homomeric complex or a heteromeric complex with OsCNGC5 or OsCNGC8. In addition, it was suggested that they can form a multi-complex with Mildew Resistance Locus O (MLO) protein or other types of ion transporters, and that their expression can be modulated by Ruptured Pollen tube (RUPO) encoding receptor-like kinase. These results shed light on understanding the regulatory mechanisms of pollen germination and pollen tube growth through calcium channels in rice.
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Affiliation(s)
- Su-Kyoung Lee
- Graduate School of Green-Bio Science and Crop Biotech Institute, Kyung Hee University, Yongin 17104, Republic of Korea
| | - Soo-Min Lee
- Graduate School of Green-Bio Science and Crop Biotech Institute, Kyung Hee University, Yongin 17104, Republic of Korea
| | - Myung-Hee Kim
- School of Applied Biosciences, Kyungpook National University, Daegu 41566, Republic of Korea
| | - Soon-Ki Park
- School of Applied Biosciences, Kyungpook National University, Daegu 41566, Republic of Korea
| | - Ki-Hong Jung
- Graduate School of Green-Bio Science and Crop Biotech Institute, Kyung Hee University, Yongin 17104, Republic of Korea
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Gating intermediates reveal inhibitory role of the voltage sensor in a cyclic nucleotide-modulated ion channel. Nat Commun 2022; 13:6919. [PMID: 36376326 PMCID: PMC9663499 DOI: 10.1038/s41467-022-34673-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Accepted: 11/02/2022] [Indexed: 11/16/2022] Open
Abstract
Understanding how ion channels gate is important for elucidating their physiological roles and targeting them in pathophysiological states. Here, we used SthK, a cyclic nucleotide-modulated channel from Spirochaeta thermophila, to define a ligand-gating trajectory that includes multiple on-pathway intermediates. cAMP is a poor partial agonist for SthK and depolarization increases SthK activity. Tuning the energy landscape by gain-of-function mutations in the voltage sensor domain (VSD) allowed us to capture multiple intermediates along the ligand-activation pathway, highlighting the allosteric linkage between VSD, cyclic nucleotide-binding (CNBD) and pore domains. Small, lateral displacements of the VSD S4 segment were necessary to open the intracellular gate, pointing to an inhibitory VSD at rest. We propose that in wild-type SthK, depolarization leads to such VSD displacements resulting in release of inhibition. In summary, we report conformational transitions along the activation pathway that reveal allosteric couplings between key sites integrating to open the intracellular gate.
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Chen Y, Dong Y, Yan J, Wang L, Yu S, Jiao K, Paquet-Durand F. Single-Cell Transcriptomic Profiling in Inherited Retinal Degeneration Reveals Distinct Metabolic Pathways in Rod and Cone Photoreceptors. Int J Mol Sci 2022; 23:12170. [PMID: 36293024 PMCID: PMC9603353 DOI: 10.3390/ijms232012170] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 09/28/2022] [Accepted: 10/08/2022] [Indexed: 08/31/2023] Open
Abstract
The cellular mechanisms underlying hereditary photoreceptor degeneration are still poorly understood. The aim of this study was to systematically map the transcriptional changes that occur in the degenerating mouse retina at the single cell level. To this end, we employed single-cell RNA-sequencing (scRNA-seq) and retinal degeneration-1 (rd1) mice to profile the impact of the disease mutation on the diverse retinal cell types during early post-natal development. The transcriptome data allowed to annotate 43,979 individual cells grouped into 20 distinct clusters. We further characterized cluster-specific metabolic and biological changes in individual cell types. Our results highlight Ca2+-signaling as relevant to hereditary photoreceptor degeneration. Although metabolic reprogramming in retina, known as the 'Warburg effect', has been documented, further metabolic changes were noticed in rd1 mice. Such metabolic changes in rd1 mutation was likely regulated through mitogen-activated protein kinase (MAPK) pathway. By combining single-cell transcriptomes and immunofluorescence staining, our study revealed cell type-specific changes in gene expression, as well as interplay between Ca2+-induced cell death and metabolic pathways.
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Affiliation(s)
- Yiyi Chen
- Institute for Ophthalmic Research, University of Tübingen, 72076 Tübingen, Germany
- Graduate Training Centre of Neuroscience, University of Tübingen, 72076 Tübingen, Germany
| | - Yujie Dong
- Yunnan Eye Institute & Key Laboratory of Yunnan Province, 650021 Kunming, China
| | - Jie Yan
- Institute for Ophthalmic Research, University of Tübingen, 72076 Tübingen, Germany
- Graduate Training Centre of Neuroscience, University of Tübingen, 72076 Tübingen, Germany
| | - Lan Wang
- Institute for Ophthalmic Research, University of Tübingen, 72076 Tübingen, Germany
- Graduate Training Centre of Neuroscience, University of Tübingen, 72076 Tübingen, Germany
| | - Shirley Yu
- Graduate Training Centre of Neuroscience, University of Tübingen, 72076 Tübingen, Germany
| | - Kangwei Jiao
- Yunnan Eye Institute & Key Laboratory of Yunnan Province, 650021 Kunming, China
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cGMP Analogues with Opposing Actions on CNG Channels Selectively Modulate Rod or Cone Photoreceptor Function. Pharmaceutics 2022; 14:pharmaceutics14102102. [PMID: 36297537 PMCID: PMC9612005 DOI: 10.3390/pharmaceutics14102102] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Revised: 09/23/2022] [Accepted: 09/28/2022] [Indexed: 11/09/2022] Open
Abstract
The vertebrate retina harbors rod and cone photoreceptors. Human vision critically depends on cone photoreceptor function. In the phototransduction cascade, cGMP activates distinct rod and cone isoforms of the cyclic nucleotide-gated (CNG) channel. Excessive cGMP levels initiate a pathophysiological rollercoaster, which starts with CNG channel over-activation, typically in rod photoreceptors. This triggers cell death of rods first, and then cones, and is the root cause of many blinding retinal diseases, including Retinitis pigmentosa. While targeting of CNG channels has been proposed for therapeutic purposes, thus far, it has not been possible to inhibit rod CNG channels without compromising cone function. Here, we present a novel strategy, based on cGMP analogues with opposing actions on CNG channels, which enables the selective modulation of either rod or cone photoreceptor activity. The combined treatment with the weak rod-selective CNG-channel inhibitor (Rp-8-Br-PET-cGMPS) and the cone-selective CNG-channel activator (8-pCPT-cGMP) essentially normalized rod CNG-channel function while preserving cone functionality at physiological and pathological cGMP levels. Hence, combinations of cGMP analogues with desired properties may elegantly address the isoform-specificity problem in future pharmacological therapies. Moreover, this strategy may allow for improvements in visual performance in certain light environments.
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Mutations within the cGMP-binding domain of CNGA1 causing autosomal recessive retinitis pigmentosa in human and animal model. Cell Death Dis 2022; 8:387. [PMID: 36115851 PMCID: PMC9482621 DOI: 10.1038/s41420-022-01185-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 09/05/2022] [Accepted: 09/06/2022] [Indexed: 11/08/2022]
Abstract
Retinitis pigmentosa is a group of progressive inherited retinal dystrophies that may present clinically as part of a syndromic entity or as an isolated (nonsyndromic) manifestation. In an Indian family suffering from retinitis pigmentosa, we identified a missense variation in CNGA1 affecting the cyclic nucleotide binding domain (CNBD) and characterized a mouse model developed with mutated CNBD. A gene panel analysis comprising 105 known RP genes was used to analyze a family with autosomal-recessive retinitis pigmentosa (arRP) and revealed that CNGA1 was affected. From sperm samples of ENU mutagenesis derived F1 mice, we re-derived a mutant with a Cnga1 mutation. Homozygous mutant mice, developing retinal degeneration, were examined for morphological and functional consequences of the mutation. In the family, we identified a rare CNGA1 variant (NM_001379270.1) c.1525 G > A; (p.Gly509Arg), which co-segregated among the affected family members. Homozygous Cnga1 mice harboring a (ENSMUST00000087213.12) c.1526 A > G (p.Tyr509Cys) mutation showed progressive degeneration in the retinal photoreceptors from 8 weeks on. This study supports a role for CNGA1 as a disease gene for arRP and provides new insights on the pathobiology of cGMP-binding domain mutations in CNGA1-RP.
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Schirmeyer J, Eick T, Schulz E, Hummert S, Sattler C, Schmauder R, Benndorf K. Subunit promotion energies for channel opening in heterotetrameric olfactory CNG channels. PLoS Comput Biol 2022; 18:e1010376. [PMID: 35998156 PMCID: PMC9512249 DOI: 10.1371/journal.pcbi.1010376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Revised: 09/26/2022] [Accepted: 07/11/2022] [Indexed: 11/18/2022] Open
Abstract
Cyclic nucleotide-gated (CNG) ion channels of olfactory sensory neurons contain three types of homologue subunits, two CNGA2 subunits, one CNGA4 subunit and one CNGB1b subunit. Each subunit carries an intracellular cyclic nucleotide binding domain (CNBD) whose occupation by up to four cyclic nucleotides evokes channel activation. Thereby, the subunits interact in a cooperative fashion. Here we studied 16 concatamers with systematically disabled, but still functional, binding sites and quantified channel activation by systems of intimately coupled state models transferred to 4D hypercubes, thereby exploiting a weak voltage dependence of the channels. We provide the complete landscape of free energies for the complex activation process of heterotetrameric channels, including 32 binding steps, in both the closed and open channel, as well as 16 closed-open isomerizations. The binding steps are specific for the subunits and show pronounced positive cooperativity for the binding of the second and the third ligand. The energetics of the closed-open isomerizations were disassembled to elementary subunit promotion energies for channel opening, ΔΔGfpn, adding to the free energy of the closed-open isomerization of the empty channel, E0. The ΔΔGfpn values are specific for the four subunits and presumably invariant for the specific patterns of liganding. In conclusion, subunit cooperativity is confined to the CNBD whereas the subunit promotion energies for channel opening are independent. Olfactory sensory neurons (OSNs) in the nose transmit the information of odor molecules to electrical signals that are conducted to central parts of the brain. Olfactory cyclic nucleotide-gated (CNG) ion channels, located in the cell membrane of the OSNs, are relevant proteins in this process. These olfactory CNG channels are formed by three types of homologue subunits and each of these subunits contains a cyclic nucleotide binding domain (CNBD). A channel is activated by the binding of up to four cyclic nucleotides. The process of channel activation is only poorly understood. Herein we analyzed this activation process in great detail by concatenating these four subunits, disabling the CNBDs by mutations and performing extended computational fit analyses providing all 32 constants for the different binding steps at different degrees of liganding and, in addition, elementary subunit promotion energies for channel opening for all subunits. Our data suggest that subunit cooperativity is confined to the action of the CNBD.
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Affiliation(s)
- Jana Schirmeyer
- Institute of Physiology II, Jena University Hospital, Friedrich Schiller University Jena, Jena, Germany
| | - Thomas Eick
- Institute of Physiology II, Jena University Hospital, Friedrich Schiller University Jena, Jena, Germany
| | - Eckhard Schulz
- Schmalkalden University of Applied Sciences, Faculty of Electrical Engineering, Blechhammer, Schmalkalden, Germany
| | - Sabine Hummert
- Institute of Physiology II, Jena University Hospital, Friedrich Schiller University Jena, Jena, Germany
- Schmalkalden University of Applied Sciences, Faculty of Electrical Engineering, Blechhammer, Schmalkalden, Germany
| | - Christian Sattler
- Institute of Physiology II, Jena University Hospital, Friedrich Schiller University Jena, Jena, Germany
| | - Ralf Schmauder
- Institute of Physiology II, Jena University Hospital, Friedrich Schiller University Jena, Jena, Germany
| | - Klaus Benndorf
- Institute of Physiology II, Jena University Hospital, Friedrich Schiller University Jena, Jena, Germany
- * E-mail:
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