1
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Juraver-Geslin H, Devotta A, Saint-Jeannet JP. Developmental roles of natriuretic peptides and their receptors. Cells Dev 2023; 176:203878. [PMID: 37742795 PMCID: PMC10841480 DOI: 10.1016/j.cdev.2023.203878] [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: 07/13/2023] [Revised: 09/18/2023] [Accepted: 09/19/2023] [Indexed: 09/26/2023]
Abstract
Natriuretic peptides and their receptors are implicated in the physiological control of blood pressure, bone growth, and cardiovascular and renal homeostasis. They mediate their action through the modulation of intracellular levels of cGMP and cAMP, two second-messengers that have broad biological roles. In this review, we briefly describe the major players of this signaling pathway and their physiological roles in the adult, and discuss several reports describing their activity in the control of various aspects of embryonic development in several species. While the core components of this signaling pathway are well conserved, their functions have diverged in the embryo and the adult to control a diverse array of biological processes.
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Affiliation(s)
- Hugo Juraver-Geslin
- Department of Molecular Pathobiology, New York University, College of Dentistry, New York, NY 10010, USA
| | - Arun Devotta
- Department of Molecular Pathobiology, New York University, College of Dentistry, New York, NY 10010, USA
| | - Jean-Pierre Saint-Jeannet
- Department of Molecular Pathobiology, New York University, College of Dentistry, New York, NY 10010, USA.
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2
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Sun F, Zhou K, Tian KY, Zhang XY, Liu W, Wang J, Zhong CP, Qiu JH, Zha DJ. Atrial Natriuretic Peptide Promotes Neurite Outgrowth and Survival of Cochlear Spiral Ganglion Neurons in vitro Through NPR-A/cGMP/PKG Signaling. Front Cell Dev Biol 2021; 9:681421. [PMID: 34268307 PMCID: PMC8276373 DOI: 10.3389/fcell.2021.681421] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Accepted: 05/10/2021] [Indexed: 01/22/2023] Open
Abstract
Sensorineural hearing loss (SNHL) is a dominant public health issue affecting millions of people around the globe, which is correlated with the irreversible deterioration of the hair cells and spiral ganglion neurons (SGNs) within the cochlea. Strategies using bioactive molecules that regulate neurite regeneration and neuronal survival to reestablish connections between auditory epithelium or implanted electrodes and SGN neurites would become attractive therapeutic candidates for SNHL. As an intracellular second messenger, cyclic guanosine-3’,5’-monophosphate (cGMP) can be synthesized through activation of particulate guanylate cyclase-coupled natriuretic peptide receptors (NPRs) by natriuretic peptides, which in turn modulates multiple aspects of neuronal functions including neuronal development and neuronal survival. As a cardiac-derived hormone, atrial natriuretic peptide (ANP), and its specific receptors (NPR-A and NPR-C) are broadly expressed in the nervous system where they might be involved in the maintenance of diverse neural functions. Despite former literatures and our reports indicating the existence of ANP and its receptors within the inner ear, particularly in the spiral ganglion, their potential regulatory mechanisms underlying functional properties of auditory neurons are still incompletely understood. Our recently published investigation revealed that ANP could promote the neurite outgrowth of SGNs by activating NPR-A/cGMP/PKG cascade in a dose-dependent manner. In the present research, the influence of ANP and its receptor-mediated downstream signaling pathways on neurite outgrowth, neurite attraction, and neuronal survival of SGNs in vitro was evaluated by employing cultures of organotypic explant and dissociated neuron from postnatal rats. Our data indicated that ANP could support and attract neurite outgrowth of SGNs and possess a high capacity to improve neuronal survival of SGNs against glutamate-induced excitotoxicity by triggering the NPR-A/cGMP/PKG pathway. The neuroregenerative and neuroprotective effects of ANP/NPRA/cGMP/PKG-dependent signaling on SGNs would represent an attractive therapeutic candidate for hearing impairment.
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Affiliation(s)
- Fei Sun
- Department of Otolaryngology-Head and Neck Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Ke Zhou
- Department of Laboratory Medicine, Institute of Clinical Laboratory Medicine of PLA, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Ke-Yong Tian
- Department of Otolaryngology-Head and Neck Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Xin-Yu Zhang
- Department of Otolaryngology-Head and Neck Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Wei Liu
- Department of Otolaryngology-Head and Neck Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Jie Wang
- Department of Otolaryngology-Head and Neck Surgery, The Affiliated Children Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Cui-Ping Zhong
- Department of Otolaryngology-Head and Neck Surgery, The 940th Hospital of Joint Logistics Support Force of PLA, Lanzhou, China
| | - Jian-Hua Qiu
- Department of Otolaryngology-Head and Neck Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Ding-Jun Zha
- Department of Otolaryngology-Head and Neck Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an, China
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3
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Schmidt H, Böttcher A, Gross T, Schmidtko A. cGMP signalling in dorsal root ganglia and the spinal cord: Various functions in development and adulthood. Br J Pharmacol 2021; 179:2361-2377. [PMID: 33939841 DOI: 10.1111/bph.15514] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Revised: 03/12/2021] [Accepted: 03/31/2021] [Indexed: 12/27/2022] Open
Abstract
Cyclic GMP (cGMP) is a second messenger that regulates numerous physiological and pathophysiological processes. In recent years, more and more studies have uncovered multiple roles of cGMP signalling pathways in the somatosensory system. Accumulating evidence suggests that cGMP regulates different cellular processes from embryonic development through to adulthood. During embryonic development, a cGMP-dependent signalling cascade in the trunk sensory system is essential for axon bifurcation, a specific form of branching of somatosensory axons. In adulthood, various cGMP signalling pathways in distinct cell populations of sensory neurons and dorsal horn neurons in the spinal cord play an important role in the processing of pain and itch. Some of the involved enzymes might serve as a target for future therapies. In this review, we summarise the knowledge regarding cGMP-dependent signalling pathways in dorsal root ganglia and the spinal cord during embryonic development and adulthood, and the potential of targeting these pathways.
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Affiliation(s)
- Hannes Schmidt
- Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, Germany
| | - Alexandra Böttcher
- Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, Germany
| | - Tilman Gross
- Institute of Pharmacology and Clinical Pharmacy, Goethe University, Frankfurt am Main, Germany
| | - Achim Schmidtko
- Institute of Pharmacology and Clinical Pharmacy, Goethe University, Frankfurt am Main, Germany
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4
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Analysis of Gene Expression Using lacZ Reporter Mouse Lines. Methods Mol Biol 2021. [PMID: 33606204 DOI: 10.1007/978-1-0716-1008-4_2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
Reporter mice transgenically expressing the bacterial (E. coli) lacZ gene encoding β-galactosidase (β-gal, EC 3.2.1.23) are a versatile and extensively used tool to study gene expression and cell lineage patterns. Enzymatic activity of the β-gal reporter can be effectively visualized at cellular resolution either histochemically using 5-bromo-4-chloro-3-indolyl-β-D-galactopyranoside (X-gal) or by immunofluorescent detection using a β-gal-specific antibody. Here, we summarize protocols for the localization of β-gal expressing cells in whole embryos or organs as well as in histological tissue sections of lacZ reporter mice and discuss their limitations and common pitfalls.
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5
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Marchetta P, Rüttiger L, Hobbs AJ, Singer W, Knipper M. The role of cGMP signalling in auditory processing in health and disease. Br J Pharmacol 2021; 179:2378-2393. [PMID: 33768519 DOI: 10.1111/bph.15455] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 03/10/2021] [Accepted: 03/17/2021] [Indexed: 11/29/2022] Open
Abstract
cGMP is generated by the cGMP-forming guanylyl cyclases (GCs), the intracellular nitric oxide (NO)-sensitive (soluble) guanylyl cyclase (sGC) and transmembrane GC (e.g. GC-A and GC-B). In summarizing the particular role of cGMP signalling for hearing, we show that GC generally do not interfere significantly with basic hearing function but rather sustain a healthy state for proper temporal coding, fast discrimination and adjustments during injury. sGC is critical for the integrity of the first synapse in the ascending auditory pathway, the inner hair cell synapse. GC-A promotes hair cell stability under stressful conditions such as acoustic trauma or ageing. GC-B plays a role in the development of efferent feed-back and gain control. Regarding the crucial role hearing has for language development, speech discrimination and cognitive brain functions, differential pharmaceutical targeting of GCs offers therapeutic promise for the restoration of hearing.
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Affiliation(s)
- Philine Marchetta
- Department of Otolaryngology, Head & Neck Surgery, Tübingen Hearing Research Centre (THRC), Molecular Physiology of Hearing, University of Tübingen, Tübingen, Germany
| | - Lukas Rüttiger
- Department of Otolaryngology, Head & Neck Surgery, Tübingen Hearing Research Centre (THRC), Molecular Physiology of Hearing, University of Tübingen, Tübingen, Germany
| | - Adrian J Hobbs
- William Harvey Research Institute, Barts & The London School of Medicine & Dentistry, Queen Mary University of London, London, UK
| | - Wibke Singer
- Department of Otolaryngology, Head & Neck Surgery, Tübingen Hearing Research Centre (THRC), Molecular Physiology of Hearing, University of Tübingen, Tübingen, Germany
| | - Marlies Knipper
- Department of Otolaryngology, Head & Neck Surgery, Tübingen Hearing Research Centre (THRC), Molecular Physiology of Hearing, University of Tübingen, Tübingen, Germany
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6
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Abstract
The 3',5'-cyclic guanosine monophosphate (cGMP)-dependent protein kinase type I (cGKI aka PKGI) is a major cardiac effector acting downstream of nitric oxide (NO)-sensitive soluble guanylyl cyclase and natriuretic peptides (NPs), which signal through transmembrane guanylyl cyclases. Consistent with the wide distribution of the cGMP-generating guanylyl cyclases, cGKI, which usually elicits its cellular effects by direct phosphorylation of its targets, is present in multiple cardiac cell types including cardiomyocytes (CMs). Although numerous targets of cGMP/cGKI in heart were identified in the past, neither their exact patho-/physiological functions nor cell-type specific roles are clear. Herein, we inform about the current knowledge on the signal transduction downstream of CM cGKI. We believe that better insights into the specific actions of cGMP and cGKI in these cells will help to guide future studies in the search for predictive biomarkers for the response to pharmacological cGMP pathway modulation. In addition, targets downstream of cGMP/cGKI may be exploited for refined and optimized diagnostic and therapeutic strategies in different types of heart disease and their causes. Importantly, key functions of these proteins and particularly sites of regulatory phosphorylation by cGKI should, at least in principle, remain intact, although upstream signaling through the second messenger cGMP is impaired or dysregulated in a stressed or diseased heart state.
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7
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Sitko AA, Goodrich LV. Making sense of neural development by comparing wiring strategies for seeing and hearing. Science 2021; 371:eaaz6317. [PMID: 33414193 PMCID: PMC8034811 DOI: 10.1126/science.aaz6317] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The ability to perceive and interact with the world depends on a diverse array of neural circuits specialized for carrying out specific computations. Each circuit is assembled using a relatively limited number of molecules and common developmental steps, from cell fate specification to activity-dependent synaptic refinement. Given this shared toolkit, how do individual circuits acquire their characteristic properties? We explore this question by comparing development of the circuitry for seeing and hearing, highlighting a few examples where differences in each system's sensory demands necessitate different developmental strategies.
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Affiliation(s)
- A A Sitko
- Department of Neurobiology, Harvard Medical School, Boston, MA, USA
| | - L V Goodrich
- Department of Neurobiology, Harvard Medical School, Boston, MA, USA.
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8
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Sun F, Zhou K, Tian KY, Wang J, Qiu JH, Zha DJ. Atrial Natriuretic Peptide Improves Neurite Outgrowth from Spiral Ganglion Neurons In Vitro through a cGMP-Dependent Manner. Neural Plast 2020; 2020:8831735. [PMID: 33193754 PMCID: PMC7643369 DOI: 10.1155/2020/8831735] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 07/07/2020] [Accepted: 07/09/2020] [Indexed: 02/06/2023] Open
Abstract
The spiral ganglion neurons (SGNs) are the primary afferent neurons in the spiral ganglion (SG), while their degeneration or loss would cause sensorineural hearing loss. As a cardiac-derived hormone, atrial natriuretic peptide (ANP) plays a critical role in cardiovascular homeostasis through binding to its functional receptors (NPR-A and NPR-C). ANP and its receptors are widely expressed in the mammalian nervous system where they could be implicated in the regulation of multiple neural functions. Although previous studies have provided direct evidence for the presence of ANP and its functional receptors in the inner ear, their presence within the cochlear SG and their regulatory roles during auditory neurotransmission and development remain largely unknown. Based on our previous findings, we investigated the expression patterns of ANP and its receptors in the cochlear SG and dissociated SGNs and determined the influence of ANP on neurite outgrowth in vitro by using organotypic SG explants and dissociated SGN cultures from postnatal rats. We have demonstrated that ANP and its receptors are expressed in neurons within the cochlear SG of postnatal rat, while ANP may promote neurite outgrowth of SGNs via the NPR-A/cGMP/PKG pathway in a dose-dependent manner. These results indicate that ANP would play a role in normal neuritogenesis of SGN during cochlear development and represents a potential therapeutic candidate to enhance regeneration and regrowth of SGN neurites.
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Affiliation(s)
- Fei Sun
- Department of Otolaryngology-Head and Neck Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi 710032, China
| | - Ke Zhou
- Center of Clinical Laboratory Medicine of PLA, Department of Laboratory Medicine, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi 710032, China
| | - Ke-yong Tian
- Department of Otolaryngology-Head and Neck Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi 710032, China
| | - Jie Wang
- Department of Otolaryngology-Head and Neck Surgery, The Affiliated Children Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi 710003, China
| | - Jian-hua Qiu
- Department of Otolaryngology-Head and Neck Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi 710032, China
| | - Ding-jun Zha
- Department of Otolaryngology-Head and Neck Surgery, Xijing Hospital, Fourth Military Medical University, Xi'an, Shaanxi 710032, China
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9
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Dumoulin A, Schmidt H, Rathjen FG. Sensory Neurons: The Formation of T-Shaped Branches Is Dependent on a cGMP-Dependent Signaling Cascade. Neuroscientist 2020; 27:47-57. [PMID: 32321356 DOI: 10.1177/1073858420913844] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Axon bifurcation - a specific form of branching of somatosensory axons characterized by the splitting of the growth cone - is mediated by a cGMP-dependent signaling cascade composed of the extracellular ligand CNP (C-type natriuretic peptide), the transmembrane receptor guanylyl cyclase Npr2 (natriuretic peptide receptor 2), and the kinase cGKI (cGMP-dependent protein kinase I). In the absence of any one of these components, the formation of T-shaped axonal branches is impaired in neurons from DRGs (dorsal root ganglia), CSGs (cranial sensory ganglia) and MTNs (mesencephalic trigeminal neurons) in the murine spinal cord or hindbrain. Instead, axons from DRGs or from CSGs extend only either in an ascending or descending direction, while axons from MTNs either elongate within the hindbrain or extend via the trigeminal ganglion to the masseter muscles. Collateral formation from non-bifurcating stem axons is not affected by impaired cGMP signaling. Activation of Npr2 requires both binding of the ligand CNP as well as phosphorylation of serine and threonine residues at the juxtamembrane regions of the receptor. The absence of bifurcation results in an altered shape of termination fields of sensory afferents in the spinal cord and resulted in impaired noxious heat sensation and nociception whereas motor coordination appeared normal.
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Affiliation(s)
- Alexandre Dumoulin
- Department of Molecular Life Sciences, University of Zürich, Zürich, Switzerland
| | - Hannes Schmidt
- Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, Germany
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10
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Abstract
The spinal cord receives, relays and processes sensory information from the periphery and integrates this information with descending inputs from supraspinal centres to elicit precise and appropriate behavioural responses and orchestrate body movements. Understanding how the spinal cord circuits that achieve this integration are wired during development is the focus of much research interest. Several families of proteins have well-established roles in guiding developing spinal cord axons, and recent findings have identified new axon guidance molecules. Nevertheless, an integrated view of spinal cord network development is lacking, and many current models have neglected the cellular and functional diversity of spinal cord circuits. Recent advances challenge the existing spinal cord axon guidance dogmas and have provided a more complex, but more faithful, picture of the ontogenesis of vertebrate spinal cord circuits.
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11
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Duncan JS, Fritzsch B, Houston DW, Ketchum EM, Kersigo J, Deans MR, Elliott KL. Topologically correct central projections of tetrapod inner ear afferents require Fzd3. Sci Rep 2019; 9:10298. [PMID: 31311957 PMCID: PMC6635624 DOI: 10.1038/s41598-019-46553-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Accepted: 06/29/2019] [Indexed: 12/27/2022] Open
Abstract
Inner ear sensory afferent connections establish sensory maps between the inner ear hair cells and the vestibular and auditory nuclei to allow vestibular and sound information processing. While molecular guidance of sensory afferents to the periphery has been well studied, molecular guidance of central projections from the ear is only beginning to emerge. Disorganized central projections of spiral ganglion neurons in a Wnt/PCP pathway mutant, Prickle1, suggest the Wnt/PCP pathway plays a role in guiding cochlear afferents to the cochlear nuclei in the hindbrain, consistent with known expression of the Wnt receptor, Frizzled3 (Fzd3) in inner ear neurons. We therefore investigated the role of Wnt signaling in central pathfinding in Fzd3 mutant mice and Fzd3 morpholino treated frogs and found aberrant central projections of vestibular afferents in both cases. Ear transplantations from knockdown to control Xenopus showed that it is the Fzd3 expressed within the ear that mediates this guidance. Also, cochlear afferents of Fzd3 mutant mice lack the orderly topological organization observed in controls. Quantification of Fzd3 expression in spiral ganglion neurons show a gradient of expression with Fzd3 being higher in the apex than in the base. Together, these results suggest that a gradient of Fzd3 in inner ear afferents directs projections to the correct dorsoventral column within the hindbrain.
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Affiliation(s)
- Jeremy S Duncan
- Department of Biological Sciences, Western Michigan University, Kalamazoo, MI, USA
| | - Bernd Fritzsch
- Department of Biology, University of Iowa, Iowa City, IA, USA
| | | | - Elizabeth M Ketchum
- Department of Biological Sciences, Western Michigan University, Kalamazoo, MI, USA
| | | | - Michael R Deans
- Department of Surgery, Division of Otolaryngology, and Department of Neurobiology & Anatomy, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Karen L Elliott
- Department of Biology, University of Iowa, Iowa City, IA, USA.
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12
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Schmidt H, Fritzsch B. Npr2 null mutants show initial overshooting followed by reduction of spiral ganglion axon projections combined with near-normal cochleotopic projection. Cell Tissue Res 2019; 378:15-32. [PMID: 31201541 DOI: 10.1007/s00441-019-03050-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Accepted: 05/20/2019] [Indexed: 12/19/2022]
Abstract
Npr2 (natriuretic peptide receptor 2) affects bifurcation of neural crest or placode-derived afferents upon entering the brain stem/spinal cord, leading to a lack of either rostral or caudal branches. Previous work has shown that early embryonic growth of cochlear and vestibular afferents is equally affected in this mutant but later work on postnatal Npr2 point mutations suggested some additional effects on the topology of afferent projections and mild functional defects. Using multicolor lipophilic dye tracing, we show that absence of Npr2 has little to no effect on the initial patterning of inner ear afferents with respect to their dorsoventral cochleotopic-specific projections. However, in contrast to control animals, we found a variable degree of embryonic extension of auditory afferents beyond the boundaries of the anterior cochlear nucleus into the cerebellum that emanates only from apical spiral ganglion neurons. Such expansion has previously only been reported for Hox gene mutants and implies an unclear interaction of Hox codes with Npr2-mediated afferent projection patterning to define boundaries. Some vestibular ganglion neurons expand their projections to reach the cochlear apex and the cochlear nuclei, comparable to previous findings in Neurod1 mutant mice. Before birth, such expansions are reduced or lost leading to truncated projections to the anteroventral cochlear nucleus and expansion of low-frequency fibers of the apex to the posteroventral cochlear nucleus.
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Affiliation(s)
- Hannes Schmidt
- Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, Germany
| | - Bernd Fritzsch
- Department of Biology & Department of Otolaryngology, CLAS, University of Iowa, 128 Jefferson Avenue, Iowa City, IA, 52242, USA.
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13
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Fritzsch B, Elliott KL, Pavlinkova G. Primary sensory map formations reflect unique needs and molecular cues specific to each sensory system. F1000Res 2019; 8:F1000 Faculty Rev-345. [PMID: 30984379 PMCID: PMC6439788 DOI: 10.12688/f1000research.17717.1] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/21/2019] [Indexed: 12/21/2022] Open
Abstract
Interaction with the world around us requires extracting meaningful signals to guide behavior. Each of the six mammalian senses (olfaction, vision, somatosensation, hearing, balance, and taste) has a unique primary map that extracts sense-specific information. Sensory systems in the periphery and their target neurons in the central nervous system develop independently and must develop specific connections for proper sensory processing. In addition, the regulation of sensory map formation is independent of and prior to central target neuronal development in several maps. This review provides an overview of the current level of understanding of primary map formation of the six mammalian senses. Cell cycle exit, combined with incompletely understood molecules and their regulation, provides chemoaffinity-mediated primary maps that are further refined by activity. The interplay between cell cycle exit, molecular guidance, and activity-mediated refinement is the basis of dominance stripes after redundant organ transplantations in the visual and balance system. A more advanced level of understanding of primary map formation could benefit ongoing restoration attempts of impaired senses by guiding proper functional connection formations of restored sensory organs with their central nervous system targets.
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Affiliation(s)
- Bernd Fritzsch
- Department of Biology, University of Iowa, Iowa City, USA
| | | | - Gabriela Pavlinkova
- Institute of Biotechnology of the Czech Academy of Sciences, Vestec, Czech Republic
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14
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Zalucki O, Harris L, Harvey TJ, Harkins D, Widagdo J, Oishi S, Matuzelski E, Yong XLH, Schmidt H, Anggono V, Burne THJ, Gronostajski RM, Piper M. NFIX-Mediated Inhibition of Neuroblast Branching Regulates Migration Within the Adult Mouse Ventricular–Subventricular Zone. Cereb Cortex 2018; 29:3590-3604. [DOI: 10.1093/cercor/bhy233] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2018] [Revised: 08/26/2018] [Accepted: 08/29/2018] [Indexed: 12/13/2022] Open
Abstract
Abstract
Understanding the migration of newborn neurons within the brain presents a major challenge in contemporary biology. Neuronal migration is widespread within the developing brain but is also important within the adult brain. For instance, stem cells within the ventricular–subventricular zone (V-SVZ) and the subgranular zone of dentate gyrus of the adult rodent brain produce neuroblasts that migrate to the olfactory bulb and granule cell layer of the dentate gyrus, respectively, where they regulate key brain functions including innate olfactory responses, learning, and memory. Critically, our understanding of the factors mediating neuroblast migration remains limited. The transcription factor nuclear factor I X (NFIX) has previously been implicated in embryonic cortical development. Here, we employed conditional ablation of Nfix from the adult mouse brain and demonstrated that the removal of this gene from either neural stem and progenitor cells, or neuroblasts, within the V-SVZ culminated in neuroblast migration defects. Mechanistically, we identified aberrant neuroblast branching, due in part to increased expression of the guanylyl cyclase natriuretic peptide receptor 2 (Npr2), as a factor contributing to abnormal migration in Nfix-deficient adult mice. Collectively, these data provide new insights into how neuroblast migration is regulated at a transcriptional level within the adult brain.
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Affiliation(s)
- Oressia Zalucki
- The School of Biomedical Sciences, The University of Queensland, Brisbane, QLD, Australia
| | - Lachlan Harris
- The School of Biomedical Sciences, The University of Queensland, Brisbane, QLD, Australia
| | - Tracey J Harvey
- The School of Biomedical Sciences, The University of Queensland, Brisbane, QLD, Australia
| | - Danyon Harkins
- The School of Biomedical Sciences, The University of Queensland, Brisbane, QLD, Australia
| | - Jocelyn Widagdo
- Queensland Brain Institute, The University of Queensland, Brisbane, QLD, Australia
- Clem Jones Centre for Ageing Dementia Research, The University of Queensland, Brisbane, QLD, Australia
| | - Sabrina Oishi
- The School of Biomedical Sciences, The University of Queensland, Brisbane, QLD, Australia
| | - Elise Matuzelski
- The School of Biomedical Sciences, The University of Queensland, Brisbane, QLD, Australia
| | - Xuan Ling Hilary Yong
- Queensland Brain Institute, The University of Queensland, Brisbane, QLD, Australia
- Clem Jones Centre for Ageing Dementia Research, The University of Queensland, Brisbane, QLD, Australia
| | - Hannes Schmidt
- Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, Germany
| | - Victor Anggono
- Queensland Brain Institute, The University of Queensland, Brisbane, QLD, Australia
- Clem Jones Centre for Ageing Dementia Research, The University of Queensland, Brisbane, QLD, Australia
| | - Thomas H J Burne
- Queensland Brain Institute, The University of Queensland, Brisbane, QLD, Australia
- Queensland Centre for Mental Health Research, The Park Centre for Mental Health, Wacol, QLD, Australia
| | - Richard M Gronostajski
- Department of Biochemistry, Program in Genetics, Genomics and Bioinformatics, Center of Excellence in Bioinformatics and Life Sciences, State University of New York at Buffalo, Buffalo, NY, USA
| | - Michael Piper
- The School of Biomedical Sciences, The University of Queensland, Brisbane, QLD, Australia
- Queensland Brain Institute, The University of Queensland, Brisbane, QLD, Australia
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15
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Regulation of the Natriuretic Peptide Receptor 2 (Npr2) by Phosphorylation of Juxtamembrane Serine and Threonine Residues Is Essential for Bifurcation of Sensory Axons. J Neurosci 2018; 38:9768-9780. [PMID: 30249793 DOI: 10.1523/jneurosci.0495-18.2018] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Revised: 08/28/2018] [Accepted: 09/18/2018] [Indexed: 12/31/2022] Open
Abstract
cGMP signaling elicited by activation of the transmembrane receptor guanylyl cyclase Npr2 (also known as guanylyl cyclase B) by the ligand CNP controls sensory axon bifurcation of DRG and cranial sensory ganglion (CSG) neurons entering the spinal cord or hindbrain, respectively. Previous studies have shown that Npr2 is phosphorylated on serine and threonine residues in its kinase homology domain (KHD). However, it is unknown whether phosphorylation of Npr2 is essential for axon bifurcation. Here, we generated a knock-in mouse line in which the seven regulatory serine and threonine residues in the KHD of Npr2 were substituted by alanine (Npr2-7A), resulting in a nonphosphorylatable enzyme. Real-time imaging of cGMP in DRG neurons with a genetically encoded fluorescent cGMP sensor or biochemical analysis of guanylyl cyclase activity in brain or lung tissue revealed the absence of CNP-induced cGMP generation in the Npr27A/7A mutant. Consequently, bifurcation of axons, but not collateral formation, from DRG or CSG in this mouse mutant was perturbed at embryonic and mature stages. In contrast, axon branching was normal in a mouse mutant in which constitutive phosphorylation of Npr2 is mimicked by a replacement of all of the seven serine and threonine sites by glutamic acid (Npr2-7E). Furthermore, we demonstrate that the Npr27A/7A mutation causes dwarfism as described for global Npr2 mutants. In conclusion, our in vivo studies provide strong evidence that phosphorylation of the seven serine and threonine residues in the KHD of Npr2 is an important regulatory element of Npr2-mediated cGMP signaling which affects physiological processes, such as axon bifurcation and bone growth.SIGNIFICANCE STATEMENT The branching of axons is a morphological hallmark of virtually all neurons. It allows an individual neuron to innervate different targets and to communicate with neurons located in different regions of the nervous system. The natriuretic peptide receptor 2 (Npr2), a transmembrane guanylyl cyclase, is essential for the initiation of bifurcation of sensory axons when entering the spinal cord or the hindbrain. By using two genetically engineered mouse lines, we show that phosphorylation of specific serine and threonine residues in juxtamembrane regions of Npr2 are required for its enzymatic activity and for axon bifurcation. These investigations might help to understand the regulation of Npr2 and its integration in intracellular signaling systems.
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Dumoulin A, Dagane A, Dittmar G, Rathjen FG. S-palmitoylation Is Required for the Control of Growth Cone Morphology of DRG Neurons by CNP-Induced cGMP Signaling. Front Mol Neurosci 2018; 11:345. [PMID: 30319353 PMCID: PMC6166100 DOI: 10.3389/fnmol.2018.00345] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2018] [Accepted: 09/04/2018] [Indexed: 12/24/2022] Open
Abstract
Genetic investigations have demonstrated that a specific form of axonal branching - the bifurcation of afferents from dorsal root ganglia (DRG), cranial sensory ganglia (CSG) and mesencephalic trigeminal neurons (MTN) – is regulated by a cGMP-dependent signaling pathway. This cascade is composed of the ligand C-type natriuretic peptide (CNP), the receptor guanylyl cyclase Npr2, and the cGMP-dependent protein kinase Iα (cGKIα). In the absence of any one of these components, axons no longer bifurcate, instead they turn in either an ascending or a descending direction. To gain further mechanistic insights into the process of axon bifurcation we applied different cell culture approaches to decipher downstream activities of cGKI in somatosensory growth cones. We demonstrate that CNP induces an enlargement of DRG growth cones via cGKI which is considered as the priming step of axon bifurcation in the spinal cord. This growth cone remodeling was both blocked by pharmacological inhibitors of S-palmitoylation and potentiated by blocking de-palmitoylation. cGKI colocalizes with the palmitoylome and vesicular structures including the endoplasmic reticulum, early endosomes, lysosomes primarily in the central domain of the growth cone as well as with the Golgi apparatus at the level of the soma. Interestingly, an acyl-biotin-exchange chemistry-based screen indicated that 8pCPT-cGMP-induced signaling induces S-palmitoylation of a restricted pool of proteins in the DRG-derived cell line F11. Overall, our data indicate that CNP-induced cGMP signaling via cGKI affects growth cone morphology of somatosensory afferents. Moreover, it also suggests that S-palmitoylation might play a role in this process.
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Affiliation(s)
| | - Alina Dagane
- Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Gunnar Dittmar
- Max Delbrück Center for Molecular Medicine, Berlin, Germany
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17
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Wolter S, Möhrle D, Schmidt H, Pfeiffer S, Zelle D, Eckert P, Krämer M, Feil R, Pilz PKD, Knipper M, Rüttiger L. GC-B Deficient Mice With Axon Bifurcation Loss Exhibit Compromised Auditory Processing. Front Neural Circuits 2018; 12:65. [PMID: 30275816 PMCID: PMC6152484 DOI: 10.3389/fncir.2018.00065] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Accepted: 08/02/2018] [Indexed: 12/20/2022] Open
Abstract
Sensory axon T-like branching (bifurcation) in neurons from dorsal root ganglia and cranial sensory ganglia depends on the molecular signaling cascade involving the secreted factor C-type natriuretic peptide, the natriuretic peptide receptor guanylyl cyclase B (GC-B; also known as Npr2) and cGMP-dependent protein kinase I (cGKI, also known as PKGI). The bifurcation of cranial nerves is suggested to be important for information processing by second-order neurons in the hindbrain or spinal cord. Indeed, mice with a spontaneous GC-B loss of function mutation (Npr2cn/cn ) display an impaired bifurcation of auditory nerve (AN) fibers. However, these mice did not show any obvious sign of impaired basal hearing. Here, we demonstrate that mice with a targeted inactivation of the GC-B gene (Npr2 lacZ/lacZ , GC-B KO mice) show an elevation of audiometric thresholds. In the inner ear, the cochlear hair cells in GC-B KO mice were nevertheless similar to those from wild type mice, justified by the typical expression of functionally relevant marker proteins. However, efferent cholinergic feedback to inner and outer hair cells was reduced in GC-B KO mice, linked to very likely reduced rapid efferent feedback. Sound-evoked AN responses of GC-B KO mice were elevated, a feature that is known to occur when the efferent axo-dendritic feedback on AN is compromised. Furthermore, late sound-evoked brainstem responses were significantly delayed in GC-B KO mice. This delay in sound response was accompanied by a weaker sensitivity of the auditory steady state response to amplitude-modulated sound stimuli. Finally, the acoustic startle response (ASR) - one of the fastest auditory responses - and the prepulse inhibition of the ASR indicated significant changes in temporal precision of auditory processing. These findings suggest that GC-B-controlled axon bifurcation of spiral ganglion neurons is important for proper activation of second-order neurons in the hindbrain and is a prerequisite for proper temporal auditory processing likely by establishing accurate efferent top-down control circuits. These data hypothesize that the bifurcation pattern of cranial nerves is important to shape spatial and temporal information processing for sensory feedback control.
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Affiliation(s)
- Steffen Wolter
- Department of Otolaryngology, Head and Neck Surgery, Molecular Physiology of Hearing, Tübingen Hearing Research Centre, University of Tübingen, Tübingen, Germany
| | - Dorit Möhrle
- Department of Otolaryngology, Head and Neck Surgery, Molecular Physiology of Hearing, Tübingen Hearing Research Centre, University of Tübingen, Tübingen, Germany
| | - Hannes Schmidt
- Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, Germany
| | - Sylvia Pfeiffer
- Department of Animal Physiology, University of Tübingen, Tübingen, Germany
| | - Dennis Zelle
- Department of Otolaryngology, Head and Neck Surgery, Physiological Acoustics and Communication, Tübingen Hearing Research Centre, University of Tübingen, Tübingen, Germany
| | - Philipp Eckert
- Department of Otolaryngology, Head and Neck Surgery, Molecular Physiology of Hearing, Tübingen Hearing Research Centre, University of Tübingen, Tübingen, Germany
| | - Michael Krämer
- Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, Germany
| | - Robert Feil
- Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, Germany
| | - Peter K D Pilz
- Department of Animal Physiology, University of Tübingen, Tübingen, Germany
| | - Marlies Knipper
- Department of Otolaryngology, Head and Neck Surgery, Molecular Physiology of Hearing, Tübingen Hearing Research Centre, University of Tübingen, Tübingen, Germany
| | - Lukas Rüttiger
- Department of Otolaryngology, Head and Neck Surgery, Molecular Physiology of Hearing, Tübingen Hearing Research Centre, University of Tübingen, Tübingen, Germany
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18
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Subramanian H, Froese A, Jönsson P, Schmidt H, Gorelik J, Nikolaev VO. Distinct submembrane localisation compartmentalises cardiac NPR1 and NPR2 signalling to cGMP. Nat Commun 2018; 9:2446. [PMID: 29934640 PMCID: PMC6014982 DOI: 10.1038/s41467-018-04891-5] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Accepted: 05/29/2018] [Indexed: 12/11/2022] Open
Abstract
Natriuretic peptides (NPs) are important hormones that regulate multiple cellular functions including cardiovascular physiology. In the heart, two natriuretic peptide receptors NPR1 and NPR2 act as membrane guanylyl cyclases to produce 3′,5′-cyclic guanosine monophosphate (cGMP). Although both receptors protect from cardiac hypertrophy, their effects on contractility are markedly different, from little effect (NPR1) to pronounced negative inotropic and positive lusitropic responses (NPR2) with unclear underlying mechanisms. Here we use a scanning ion conductance microscopy (SICM) approach combined with Förster resonance energy transfer (FRET)-based cGMP biosensors to show that whereas NPR2 is uniformly localised on the cardiomyocyte membrane, functional NPR1 receptors are found exclusively in membrane invaginations called transverse (T)-tubules. This leads to far-reaching CNP/NPR2/cGMP signals, whereas ANP/NPR1/cGMP signals are highly confined to T-tubular microdomains by local pools of phosphodiesterase 2. This provides a previously unrecognised molecular basis for clearly distinct functional effects engaged by different cGMP producing membrane receptors. Natriuretic peptides (NPs) are important hormones that regulate cardiovascular physiology by increasing cGMP levels in cardiomyocytes. Here the authors use scanning ion conductance microscopy and a cGMP FRET sensor to identify a differential localisation pattern for the natriuretic peptide receptors within the heart.
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Affiliation(s)
- Hariharan Subramanian
- Institute of Experimental Cardiovascular Research, University Medical Center Hamburg-Eppendorf, Martnistr. 52, D-20246, Hamburg, Germany.,DZHK (German Center for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, Martnistr. 52, D-20246, Hamburg, Germany
| | - Alexander Froese
- Institute of Experimental Cardiovascular Research, University Medical Center Hamburg-Eppendorf, Martnistr. 52, D-20246, Hamburg, Germany.,DZHK (German Center for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, Martnistr. 52, D-20246, Hamburg, Germany.,Clinic of Cardiology and Pulmonology, University Medical Center Göttingen, Robert-Koch-Str. 40, D-37075, Göttingen, Germany
| | - Peter Jönsson
- Department of Chemistry, Lund University, Naturvetarvägen 14, SE-221 00, Lund, Sweden
| | - Hannes Schmidt
- Interfaculty Institute of Biochemistry, University of Tübingen, Hoppe-Seyler-Straße 4, D-72076, Tübingen, Germany
| | - Julia Gorelik
- Myocardial Function, National Heart and Lung Institute, ICTEM, Hammersmith Hospital, Imperial College London, Du Cane Road, W12 0NN, London, UK.
| | - Viacheslav O Nikolaev
- Institute of Experimental Cardiovascular Research, University Medical Center Hamburg-Eppendorf, Martnistr. 52, D-20246, Hamburg, Germany. .,DZHK (German Center for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, Martnistr. 52, D-20246, Hamburg, Germany.
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Ter-Avetisyan G, Dumoulin A, Herrel A, Schmidt H, Strump J, Afzal S, Rathjen FG. Loss of Axon Bifurcation in Mesencephalic Trigeminal Neurons Impairs the Maximal Biting Force in Npr2-Deficient Mice. Front Cell Neurosci 2018; 12:153. [PMID: 29962937 PMCID: PMC6013911 DOI: 10.3389/fncel.2018.00153] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Accepted: 05/16/2018] [Indexed: 11/13/2022] Open
Abstract
Bifurcation of axons from dorsal root ganglion (DRG) and cranial sensory ganglion (CSG) neurons is mediated by a cGMP-dependent signaling pathway composed of the ligand C-type natriuretic peptide (CNP), the receptor guanylyl cyclase Npr2 and the cGMP-dependent protein kinase I (cGKI). Here, we demonstrate that mesencephalic trigeminal neurons (MTN) which are the only somatosensory neurons whose cell bodies are located within the CNS co-express Npr2 and cGKI. Afferents of MTNs form Y-shaped branches in rhombomere 2 where the ligand CNP is expressed. Analyzing mouse mutants deficient for CNP or Npr2 we found that in the absence of CNP-induced cGMP signaling MTN afferents no longer bifurcate and instead extend either into the trigeminal root or caudally in the hindbrain. Since MTNs provide sensory information from jaw closing muscles and periodontal ligaments we measured the bite force of conditional mouse mutants of Npr2 (Npr2flox/flox;Engr1Cre ) that lack bifurcation of MTN whereas the bifurcation of trigeminal afferents is normal. Our study revealed that the maximal biting force of both sexes is reduced in Npr2flox/flox;Engr1Cre mice as compared to their Npr2flox/flox littermate controls. In conclusion sensory feedback mechanisms from jaw closing muscles or periodontal ligaments might be impaired in the absence of MTN axon bifurcation.
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Affiliation(s)
| | | | - Anthony Herrel
- Département Adaptations du Vivant, UMR 7179 Centre National de la Recherche Scientifique/MNHN, Paris, France
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20
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Iwasato T, Erzurumlu RS. Development of tactile sensory circuits in the CNS. Curr Opin Neurobiol 2018; 53:66-75. [PMID: 29908482 DOI: 10.1016/j.conb.2018.06.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 04/30/2018] [Accepted: 06/01/2018] [Indexed: 12/13/2022]
Abstract
Molecular identification of neuronal types and genetic and imaging approaches to characterize their properties reveal morphological, physiological and dynamic aspects of sensory circuit development. Here we focus on the mouse tactile sensory circuitry, with particular emphasis on the main trigeminal pathway that connects the whiskers, the major tactile organ in rodents, to the neocortex. At each level of this pathway, neurogenesis, axonal elongation, pathfinding, target recognition and circuit reorganization including dendritic refinement of cortical layer 4 neurons occur contemporaneously and a multitude of molecular signals are used in differing combinations. We highlight recent advances in development of tactile circuitry and note gaps in our understanding.
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Affiliation(s)
- Takuji Iwasato
- National Institute of Genetics, Mishima, Japan; Department of Genetics, SOKENDAI, Mishima, Japan
| | - Reha S Erzurumlu
- Department of Anatomy and Neurobiology, School of Medicine, University of Maryland, Baltimore, MD, USA.
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21
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Dumoulin A, Ter-Avetisyan G, Schmidt H, Rathjen FG. Molecular Analysis of Sensory Axon Branching Unraveled a cGMP-Dependent Signaling Cascade. Int J Mol Sci 2018; 19:E1266. [PMID: 29695045 PMCID: PMC5983660 DOI: 10.3390/ijms19051266] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Revised: 04/15/2018] [Accepted: 04/20/2018] [Indexed: 01/11/2023] Open
Abstract
Axonal branching is a key process in the establishment of circuit connectivity within the nervous system. Molecular-genetic studies have shown that a specific form of axonal branching—the bifurcation of sensory neurons at the transition zone between the peripheral and the central nervous system—is regulated by a cyclic guanosine monophosphate (cGMP)-dependent signaling cascade which is composed of C-type natriuretic peptide (CNP), the receptor guanylyl cyclase Npr2, and cGMP-dependent protein kinase Iα (cGKIα). In the absence of any one of these components, neurons in dorsal root ganglia (DRG) and cranial sensory ganglia no longer bifurcate, and instead turn in either an ascending or a descending direction. In contrast, collateral axonal branch formation which represents a second type of axonal branch formation is not affected by inactivation of CNP, Npr2, or cGKI. Whereas axon bifurcation was lost in mouse mutants deficient for components of CNP-induced cGMP formation; the absence of the cGMP-degrading enzyme phosphodiesterase 2A had no effect on axon bifurcation. Adult mice that lack sensory axon bifurcation due to the conditional inactivation of Npr2-mediated cGMP signaling in DRG neurons demonstrated an altered shape of sensory axon terminal fields in the spinal cord, indicating that elaborate compensatory mechanisms reorganize neuronal circuits in the absence of bifurcation. On a functional level, these mice showed impaired heat sensation and nociception induced by chemical irritants, whereas responses to cold sensation, mechanical stimulation, and motor coordination are normal. These data point to a critical role of axon bifurcation for the processing of acute pain perception.
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Affiliation(s)
| | | | - Hannes Schmidt
- Interfaculty Institute of Biochemistry, University of Tübingen, Hoppe-Seyler-Str. 4, 72076 Tübingen, Germany.
| | - Fritz G Rathjen
- Max-Delbrück-Center, Robert-Rössle-Str. 10, 13092 Berlin, Germany.
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22
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Tröster P, Haseleu J, Petersen J, Drees O, Schmidtko A, Schwaller F, Lewin GR, Ter-Avetisyan G, Winter Y, Peters S, Feil S, Feil R, Rathjen FG, Schmidt H. The Absence of Sensory Axon Bifurcation Affects Nociception and Termination Fields of Afferents in the Spinal Cord. Front Mol Neurosci 2018; 11:19. [PMID: 29472841 PMCID: PMC5809486 DOI: 10.3389/fnmol.2018.00019] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Accepted: 01/15/2018] [Indexed: 12/16/2022] Open
Abstract
A cGMP signaling cascade composed of C-type natriuretic peptide, the guanylyl cyclase receptor Npr2 and cGMP-dependent protein kinase I (cGKI) controls the bifurcation of sensory axons upon entering the spinal cord during embryonic development. However, the impact of axon bifurcation on sensory processing in adulthood remains poorly understood. To investigate the functional consequences of impaired axon bifurcation during adult stages we generated conditional mouse mutants of Npr2 and cGKI (Npr2fl/fl;Wnt1Cre and cGKIKO/fl;Wnt1Cre) that lack sensory axon bifurcation in the absence of additional phenotypes observed in the global knockout mice. Cholera toxin labeling in digits of the hind paw demonstrated an altered shape of sensory neuron termination fields in the spinal cord of conditional Npr2 mouse mutants. Behavioral testing of both sexes indicated that noxious heat sensation and nociception induced by chemical irritants are impaired in the mutants, whereas responses to cold sensation, mechanical stimulation, and motor coordination are not affected. Recordings from C-fiber nociceptors in the hind limb skin showed that Npr2 function was not required to maintain normal heat sensitivity of peripheral nociceptors. Thus, the altered behavioral responses to noxious heat found in Npr2fl/fl;Wnt1Cre mice is not due to an impaired C-fiber function. Overall, these data point to a critical role of axonal bifurcation for the processing of pain induced by heat or chemical stimuli.
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Affiliation(s)
- Philip Tröster
- Developmental Neurobiology, Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Julia Haseleu
- Molecular Physiology of Somatic Sensation, Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Jonas Petersen
- Institute of Pharmacology, College of Pharmacy, Goethe University, Frankfurt am Main, Germany.,Institute of Pharmacology and Toxicology, Zentrum für Biomedizinische Ausbildung und Forschung (ZBAF), Witten/Herdecke University, Witten, Germany
| | - Oliver Drees
- Institute of Pharmacology and Toxicology, Zentrum für Biomedizinische Ausbildung und Forschung (ZBAF), Witten/Herdecke University, Witten, Germany
| | - Achim Schmidtko
- Institute of Pharmacology, College of Pharmacy, Goethe University, Frankfurt am Main, Germany.,Institute of Pharmacology and Toxicology, Zentrum für Biomedizinische Ausbildung und Forschung (ZBAF), Witten/Herdecke University, Witten, Germany
| | - Frederick Schwaller
- Molecular Physiology of Somatic Sensation, Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Gary R Lewin
- Molecular Physiology of Somatic Sensation, Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Gohar Ter-Avetisyan
- Developmental Neurobiology, Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - York Winter
- Cognitive Neurobiology, Humboldt University of Berlin, Berlin, Germany
| | - Stefanie Peters
- Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, Germany
| | - Susanne Feil
- Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, Germany
| | - Robert Feil
- Interfaculty Institute of Biochemistry, University of Tübingen, Tübingen, Germany
| | - Fritz G Rathjen
- Developmental Neurobiology, Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Hannes Schmidt
- Developmental Neurobiology, Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
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23
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Egbert JR, Yee SP, Jaffe LA. Luteinizing hormone signaling phosphorylates and activates the cyclic GMP phosphodiesterase PDE5 in mouse ovarian follicles, contributing an additional component to the hormonally induced decrease in cyclic GMP that reinitiates meiosis. Dev Biol 2018; 435:6-14. [PMID: 29341896 DOI: 10.1016/j.ydbio.2018.01.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 01/10/2018] [Accepted: 01/11/2018] [Indexed: 10/18/2022]
Abstract
Prior to birth, oocytes within mammalian ovarian follicles initiate meiosis, but then arrest in prophase until puberty, when with each reproductive cycle, one or more follicles are stimulated by luteinizing hormone (LH) to resume meiosis in preparation for fertilization. Within preovulatory follicles, granulosa cells produce high levels of cGMP, which diffuses into the oocyte to maintain meiotic arrest. LH signaling restarts meiosis by rapidly lowering the levels of cGMP in the follicle and oocyte. Part of this decrease is mediated by the dephosphorylation and inactivation the NPR2 guanylyl cyclase in response to LH, but the mechanism for the remainder of the cGMP decrease is unknown. At least one cGMP phosphodiesterase, PDE5, is activated by LH signaling, which would contribute to lowering cGMP. PDE5 exhibits increased cGMP-hydrolytic activity when phosphorylated on serine 92, and we recently demonstrated that LH signaling phosphorylates PDE5 on this serine and increases its activity in rat follicles. To test the extent to which this mechanism contributes to the cGMP decrease that restarts meiosis, we generated a mouse line in which serine 92 was mutated to alanine (Pde5-S92A), such that it cannot be phosphorylated. Here we show that PDE5 phosphorylation is required for the LH-induced increase in cGMP-hydrolytic activity, but that this increase has only a modest effect on the LH-induced cGMP decrease in mouse follicles, and does not affect the timing of meiotic resumption. Though we show that the activation of PDE5 is among the mechanisms contributing to the cGMP decrease, these results suggest that another cGMP phosphodiesterase is also activated by LH signaling.
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Affiliation(s)
- Jeremy R Egbert
- Department of Cell Biology, UConn Health, 263 Farmington Ave, Farmington, CT 06030, USA.
| | - Siu-Pok Yee
- Department of Cell Biology, UConn Health, 263 Farmington Ave, Farmington, CT 06030, USA; Center for Mouse Genome Modification, UConn Health, 263 Farmington Ave, Farmington, CT 06030, USA.
| | - Laurinda A Jaffe
- Department of Cell Biology, UConn Health, 263 Farmington Ave, Farmington, CT 06030, USA.
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24
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Shuhaibar LC, Robinson JW, Vigone G, Shuhaibar NP, Egbert JR, Baena V, Uliasz TF, Kaback D, Yee SP, Feil R, Fisher MC, Dealy CN, Potter LR, Jaffe LA. Dephosphorylation of the NPR2 guanylyl cyclase contributes to inhibition of bone growth by fibroblast growth factor. eLife 2017; 6:31343. [PMID: 29199951 PMCID: PMC5745078 DOI: 10.7554/elife.31343] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Accepted: 12/02/2017] [Indexed: 01/17/2023] Open
Abstract
Activating mutations in fibroblast growth factor (FGF) receptor 3 and inactivating mutations in the NPR2 guanylyl cyclase both cause severe short stature, but how these two signaling systems interact to regulate bone growth is poorly understood. Here, we show that bone elongation is increased when NPR2 cannot be dephosphorylated and thus produces more cyclic GMP. By developing an in vivo imaging system to measure cyclic GMP production in intact tibia, we show that FGF-induced dephosphorylation of NPR2 decreases its guanylyl cyclase activity in growth plate chondrocytes in living bone. The dephosphorylation requires a PPP-family phosphatase. Thus FGF signaling lowers cyclic GMP production in the growth plate, which counteracts bone elongation. These results define a new component of the signaling network by which activating mutations in the FGF receptor inhibit bone growth. Between birth and puberty, the bones of mammals grow drastically in length. This process is controlled by many proteins, and mutations affecting these proteins can cause bones to either be too long or too short. For example, mutations of a protein called the fibroblast growth factor receptor, or FGF for short, and a protein called NPR2, can cause similar forms of dwarfism – a condition characterized by short stature. The FGF protein controls bone growth, and people with overactive receptors for FGF suffer from a form of dwarfism known as achondroplasia, while people that lack FGF receptors have longer bones. The NPR2 protein, on the other hand, produces a molecule called cGMP, which is necessary for the bones to grow. When NPR2 is blocked, less cGMP is produced, which results in shorter limbs. Previous studies of bone cells grown in the laboratory have shown that these two proteins are linked by a chain of chemical messages. When the FGF receptor is active, phosphate molecules are removed from the NPR2 protein, which reduces the amount of GMP produced. However, until now it was not known whether this mechanism also controls growth in actual bones. Here, Shuhaibar et al. used genetically modified mice in which the phosphate group could not be removed from their NPR2 enzyme. As a result, the bones of these mice were longer than usual. Shuhaibar et al. then developed an imaging technique to examine the region in the bone were growth happens. To see whether FGF reduces the amount of cGMP produced by NPR2 in these areas, cGMP was detected with a fluorescent sensor in order to be tracked. In normal mice, the FGF receptor reduced the rate at which cGMP was produced, but in mice with mutated NPR2, this did not happen. When the cells could not remove the phosphates from NPR2, cGMP levels stayed high and the bones grew longer. These findings reveal new insights into the molecular causes of dwarfism. The next step will be to identify the enzyme responsible for removing phosphate from NPR2. Blocking its activity could help to enhance bone growth. In the future, this could lead to new drug treatments for achondroplasia.
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Affiliation(s)
- Leia C Shuhaibar
- Department of Cell Biology, University of Connecticut Health Center, Farmington, United States
| | - Jerid W Robinson
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, United States
| | - Giulia Vigone
- Department of Cell Biology, University of Connecticut Health Center, Farmington, United States
| | - Ninna P Shuhaibar
- Department of Cell Biology, University of Connecticut Health Center, Farmington, United States
| | - Jeremy R Egbert
- Department of Cell Biology, University of Connecticut Health Center, Farmington, United States
| | - Valentina Baena
- Department of Cell Biology, University of Connecticut Health Center, Farmington, United States
| | - Tracy F Uliasz
- Department of Cell Biology, University of Connecticut Health Center, Farmington, United States
| | - Deborah Kaback
- Department of Cell Biology, University of Connecticut Health Center, Farmington, United States
| | - Siu-Pok Yee
- Department of Cell Biology, University of Connecticut Health Center, Farmington, United States
| | - Robert Feil
- Interfakultäres Institut für Biochemie, University of Tübingen, Tübingen, Germany
| | - Melanie C Fisher
- Center for Regenerative Medicine and Skeletal Development, University of Connecticut Health Center, Farmington, United States
| | - Caroline N Dealy
- Center for Regenerative Medicine and Skeletal Development, University of Connecticut Health Center, Farmington, United States
| | - Lincoln R Potter
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, United States
| | - Laurinda A Jaffe
- Department of Cell Biology, University of Connecticut Health Center, Farmington, United States
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25
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Woodward Z, Prickett TC, Espiner EA, Anderson TJ. Central and systemic C-type Natriuretic Peptide are both reduced in Parkinson's Disease. Parkinsonism Relat Disord 2017; 43:15-19. [DOI: 10.1016/j.parkreldis.2017.06.019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Revised: 06/02/2017] [Accepted: 06/26/2017] [Indexed: 10/19/2022]
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Dephosphorylation is the mechanism of fibroblast growth factor inhibition of guanylyl cyclase-B. Cell Signal 2017; 40:222-229. [PMID: 28964968 DOI: 10.1016/j.cellsig.2017.09.021] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Revised: 09/19/2017] [Accepted: 09/26/2017] [Indexed: 12/30/2022]
Abstract
Activating mutations in fibroblast growth factor receptor 3 (FGFR3) and inactivating mutations of guanylyl cyclase-B (GC-B, also called NPRB or NPR2) cause dwarfism. FGF exposure inhibits GC-B activity in a chondrocyte cell line, but the mechanism of the inactivation is not known. Here, we report that FGF exposure causes dephosphorylation of GC-B in rat chondrosarcoma cells, which correlates with a rapid, potent and reversible inhibition of C-type natriuretic peptide-dependent activation of GC-B. Cells expressing a phosphomimetic mutant of GC-B that cannot be inactivated by dephosphorylation because it contains glutamate substitutions for all known phosphorylation sites showed no decrease in GC-B activity in response to FGF. We conclude that FGF rapidly inactivates GC-B by a reversible dephosphorylation mechanism, which may contribute to the signaling network by which activated FGFR3 causes dwarfism.
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Valek L, Häussler A, Dröse S, Eaton P, Schröder K, Tegeder I. Redox-guided axonal regrowth requires cyclic GMP dependent protein kinase 1: Implication for neuropathic pain. Redox Biol 2016; 11:176-191. [PMID: 27978504 PMCID: PMC5156608 DOI: 10.1016/j.redox.2016.12.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Revised: 11/03/2016] [Accepted: 12/02/2016] [Indexed: 01/27/2023] Open
Abstract
Cyclic GMP-dependent protein kinase 1 (PKG1) mediates presynaptic nociceptive long-term potentiation (LTP) in the spinal cord and contributes to inflammatory pain in rodents but the present study revealed opposite effects in the context of neuropathic pain. We used a set of loss-of-function models for in vivo and in vitro studies to address this controversy: peripheral neuron specific deletion (SNS-PKG1-/-), inducible deletion in subsets of neurons (SLICK-PKG1-/-) and redox-dead PKG1 mutants. In contrast to inflammatory pain, SNS-PKG1-/- mice developed stronger neuropathic hyperalgesia associated with an impairment of nerve regeneration, suggesting specific repair functions of PKG1. Although PKG1 accumulated at the site of injury, its activity was lost in the proximal nerve due to a reduction of oxidation-dependent dimerization, which was a consequence of mitochondrial damage in injured axons. In vitro, PKG1 deficiency or its redox-insensitivity resulted in enhanced outgrowth and reduction of growth cone collapse in response to redox signals, which presented as oxidative hotspots in growing cones. At the molecular level, PKG1 deficiency caused a depletion of phosphorylated cofilin, which is essential for growth cone collapse and guidance. Hence, redox-mediated guidance required PKG1 and consequently, its deficiency in vivo resulted in defective repair and enhanced neuropathic pain after nerve injury. PKG1-dependent repair functions will outweigh its signaling functions in spinal nociceptive LTP, so that inhibition of PKG1 is no option for neuropathic pain. Axonal injury leads mitochondrial damage. The loss of signaling ROS is associated with a reduction of redox-dependent autoactivation of PKG1. Loss of PKG1 impairs peripheral nerve regeneration and aggravates neuropathic pain in mice. Oxidative hot spots are generated in spiky growth cones and trigger growth cone collapse via PKG1. Malfunctioning of this redox-PKG1 guided growth cone collapse leads to aberrant outgrowth.
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Affiliation(s)
- Lucie Valek
- Depts. of Clinical Pharmacology, Goethe-University Hospital, Frankfurt, Germany
| | - Annett Häussler
- Depts. of Clinical Pharmacology, Goethe-University Hospital, Frankfurt, Germany
| | - Stefan Dröse
- Depts. of Anaesthesiology, Goethe-University Hospital, Frankfurt, Germany
| | - Philipp Eaton
- King's College of London, Cardiovascular Division, The Rayne Institute, St. Thomas' Hospital, London, United Kingdom
| | - Katrin Schröder
- Depts. of Cardiovascular Physiology, Goethe-University Hospital, Frankfurt, Germany
| | - Irmgard Tegeder
- Depts. of Clinical Pharmacology, Goethe-University Hospital, Frankfurt, Germany.
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Schmidt H, Peters S, Frank K, Wen L, Feil R, Rathjen FG. Dorsal root ganglion axon bifurcation tolerates increased cyclic GMP levels: the role of phosphodiesterase 2A and scavenger receptor Npr3. Eur J Neurosci 2016; 44:2991-3000. [PMID: 27740716 DOI: 10.1111/ejn.13434] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Revised: 09/21/2016] [Accepted: 10/05/2016] [Indexed: 01/01/2023]
Abstract
A cyclic GMP (cGMP) signaling pathway, comprising C-type natriuretic peptide (CNP), its guanylate cyclase receptor Npr2, and cGMP-dependent protein kinase I, is critical for the bifurcation of dorsal root ganglion (DRG) and cranial sensory ganglion axons when entering the mouse spinal cord and the hindbrain respectively. However, the identity and functional relevance of phosphodiesterases (PDEs) that degrade cGMP in DRG neurons are not completely understood. Here, we asked whether regulation of the intracellular cGMP concentration by PDEs modulates the branching of sensory axons. Real-time imaging of cGMP with a genetically encoded fluorescent cGMP sensor, RT-PCR screens, in situ hybridization, and immunohistology combined with the analysis of mutant mice identified PDE2A as the major enzyme for the degradation of CNP-induced cGMP in embryonic DRG neurons. Tracking of PDE2A-deficient DRG sensory axons in conjunction with cGMP measurements indicated that axon bifurcation tolerates increased cGMP concentrations. As we found that the natriuretic peptide scavenger receptor Npr3 is expressed by cells associated with dorsal roots but not in DRG neurons itself at early developmental stages, we analyzed axonal branching in the absence of Npr3. In Npr3-deficient mice, the majority of sensory axons showed normal bifurcation, but a small population of axons (13%) was unable to form T-like branches and generated turns in rostral or caudal directions only. Taken together, this study shows that sensory axon bifurcation is insensitive to increases of CNP-induced cGMP levels and Npr3 does not have an important scavenging function in this axonal system.
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Affiliation(s)
- Hannes Schmidt
- Max-Delbrück-Centrum für Molekulare Medizin in der Helmholtz-Gemeinschaft, 13092, Berlin, Germany
| | - Stefanie Peters
- Interfakultäres Institut für Biochemie, University of Tübingen, 72076, Tübingen, Germany
| | - Katharina Frank
- Max-Delbrück-Centrum für Molekulare Medizin in der Helmholtz-Gemeinschaft, 13092, Berlin, Germany
| | - Lai Wen
- Interfakultäres Institut für Biochemie, University of Tübingen, 72076, Tübingen, Germany
| | - Robert Feil
- Interfakultäres Institut für Biochemie, University of Tübingen, 72076, Tübingen, Germany
| | - Fritz G Rathjen
- Max-Delbrück-Centrum für Molekulare Medizin in der Helmholtz-Gemeinschaft, 13092, Berlin, Germany
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Abstract
cGMP controls many cellular functions ranging from growth, viability, and differentiation to contractility, secretion, and ion transport. The mammalian genome encodes seven transmembrane guanylyl cyclases (GCs), GC-A to GC-G, which mainly modulate submembrane cGMP microdomains. These GCs share a unique topology comprising an extracellular domain, a short transmembrane region, and an intracellular COOH-terminal catalytic (cGMP synthesizing) region. GC-A mediates the endocrine effects of atrial and B-type natriuretic peptides regulating arterial blood pressure/volume and energy balance. GC-B is activated by C-type natriuretic peptide, stimulating endochondral ossification in autocrine way. GC-C mediates the paracrine effects of guanylins on intestinal ion transport and epithelial turnover. GC-E and GC-F are expressed in photoreceptor cells of the retina, and their activation by intracellular Ca(2+)-regulated proteins is essential for vision. Finally, in the rodent system two olfactorial GCs, GC-D and GC-G, are activated by low concentrations of CO2and by peptidergic (guanylins) and nonpeptidergic odorants as well as by coolness, which has implications for social behaviors. In the past years advances in human and mouse genetics as well as the development of sensitive biosensors monitoring the spatiotemporal dynamics of cGMP in living cells have provided novel relevant information about this receptor family. This increased our understanding of the mechanisms of signal transduction, regulation, and (dys)function of the membrane GCs, clarified their relevance for genetic and acquired diseases and, importantly, has revealed novel targets for therapies. The present review aims to illustrate these different features of membrane GCs and the main open questions in this field.
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Affiliation(s)
- Michaela Kuhn
- Institute of Physiology, University of Würzburg, Würzburg, Germany
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30
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Wolter S, Möhrle D, Zelle D, Knipper M, Schmidt H, Rüttiger L. The role of particulate guanylyl cyclase B (GC-B) in auditory function in adult mice. BMC Pharmacol Toxicol 2015. [PMCID: PMC4565526 DOI: 10.1186/2050-6511-16-s1-a102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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31
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Dephosphorylation of juxtamembrane serines and threonines of the NPR2 guanylyl cyclase is required for rapid resumption of oocyte meiosis in response to luteinizing hormone. Dev Biol 2015; 409:194-201. [PMID: 26522847 DOI: 10.1016/j.ydbio.2015.10.025] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Revised: 10/15/2015] [Accepted: 10/20/2015] [Indexed: 01/14/2023]
Abstract
The meiotic cell cycle of mammalian oocytes starts during embryogenesis and then pauses until luteinizing hormone (LH) acts on the granulosa cells of the follicle surrounding the oocyte to restart the cell cycle. An essential event in this process is a decrease in cyclic GMP in the granulosa cells, and part of the cGMP decrease results from dephosphorylation and inactivation of the natriuretic peptide receptor 2 (NPR2) guanylyl cyclase, also known as guanylyl cyclase B. However, it is unknown whether NPR2 dephosphorylation is essential for LH-induced meiotic resumption. Here, we prevented NPR2 dephosphorylation by generating a mouse line in which the seven regulatory serines and threonines of NPR2 were changed to the phosphomimetic amino acid glutamate (Npr2-7E). Npr2-7E/7E follicles failed to show a decrease in enzyme activity in response to LH, and the cGMP decrease was attenuated; correspondingly, LH-induced meiotic resumption was delayed. Meiotic resumption in response to EGF receptor activation was likewise delayed, indicating that NPR2 dephosphorylation is a component of the pathway by which EGF receptor activation mediates LH signaling. We also found that most of the NPR2 protein in the follicle was present in the mural granulosa cells. These findings indicate that NPR2 dephosphorylation in the mural granulosa cells is essential for the normal progression of meiosis in response to LH and EGF receptor activation. In addition, these studies provide the first demonstration that a change in phosphorylation of a transmembrane guanylyl cyclase regulates a physiological process, a mechanism that may also control other developmental events.
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32
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Lu CC, Cao XJ, Wright S, Ma L, Oertel D, Goodrich LV. Mutation of Npr2 leads to blurred tonotopic organization of central auditory circuits in mice. PLoS Genet 2014; 10:e1004823. [PMID: 25473838 PMCID: PMC4256264 DOI: 10.1371/journal.pgen.1004823] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Accepted: 10/14/2014] [Indexed: 12/02/2022] Open
Abstract
Tonotopy is a fundamental organizational feature of the auditory system. Sounds are encoded by the spatial and temporal patterns of electrical activity in spiral ganglion neurons (SGNs) and are transmitted via tonotopically ordered processes from the cochlea through the eighth nerve to the cochlear nuclei. Upon reaching the brainstem, SGN axons bifurcate in a stereotyped pattern, innervating target neurons in the anteroventral cochlear nucleus (aVCN) with one branch and in the posteroventral and dorsal cochlear nuclei (pVCN and DCN) with the other. Each branch is tonotopically organized, thereby distributing acoustic information systematically along multiple parallel pathways for processing in the brainstem. In mice with a mutation in the receptor guanylyl cyclase Npr2, this spatial organization is disrupted. Peripheral SGN processes appear normal, but central SGN processes fail to bifurcate and are disorganized as they exit the auditory nerve. Within the cochlear nuclei, the tonotopic organization of the SGN terminal arbors is blurred and the aVCN is underinnervated with a reduced convergence of SGN inputs onto target neurons. The tonotopy of circuitry within the cochlear nuclei is also degraded, as revealed by changes in the topographic mapping of tuberculoventral cell projections from DCN to VCN. Nonetheless, Npr2 mutant SGN axons are able to transmit acoustic information with normal sensitivity and timing, as revealed by auditory brainstem responses and electrophysiological recordings from VCN neurons. Although most features of signal transmission are normal, intermittent failures were observed in responses to trains of shocks, likely due to a failure in action potential conduction at branch points in Npr2 mutant afferent fibers. Our results show that Npr2 is necessary for the precise spatial organization typical of central auditory circuits, but that signals are still transmitted with normal timing, and that mutant mice can hear even with these deficits.
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Affiliation(s)
- Cindy C. Lu
- Department of Neurobiology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Xiao-Jie Cao
- Department of Neuroscience, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, United States of America
| | - Samantha Wright
- Department of Neuroscience, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, United States of America
| | - Le Ma
- Department of Cell and Neurobiology, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
| | - Donata Oertel
- Department of Neuroscience, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, United States of America
| | - Lisa V. Goodrich
- Department of Neurobiology, Harvard Medical School, Boston, Massachusetts, United States of America
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Egbert JR, Shuhaibar LC, Edmund AB, Van Helden DA, Robinson JW, Uliasz TF, Baena V, Geerts A, Wunder F, Potter LR, Jaffe LA. Dephosphorylation and inactivation of NPR2 guanylyl cyclase in granulosa cells contributes to the LH-induced decrease in cGMP that causes resumption of meiosis in rat oocytes. Development 2014; 141:3594-604. [PMID: 25183874 DOI: 10.1242/dev.112219] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
In mammals, the meiotic cell cycle of oocytes starts during embryogenesis and then pauses. Much later, in preparation for fertilization, oocytes within preovulatory follicles resume meiosis in response to luteinizing hormone (LH). Before LH stimulation, the arrest is maintained by diffusion of cyclic (c)GMP into the oocyte from the surrounding granulosa cells, where it is produced by the guanylyl cyclase natriuretic peptide receptor 2 (NPR2). LH rapidly reduces the production of cGMP, but how this occurs is unknown. Here, using rat follicles, we show that within 10 min, LH signaling causes dephosphorylation and inactivation of NPR2 through a process that requires the activity of phosphoprotein phosphatase (PPP)-family members. The rapid dephosphorylation of NPR2 is accompanied by a rapid phosphorylation of the cGMP phosphodiesterase PDE5, an enzyme whose activity is increased upon phosphorylation. Later, levels of the NPR2 agonist C-type natriuretic peptide decrease in the follicle, and these sequential events contribute to the decrease in cGMP that causes meiosis to resume in the oocyte.
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Affiliation(s)
- Jeremy R Egbert
- Department of Cell Biology, University of Connecticut Health Center, Farmington, CT 06030, USA
| | - Leia C Shuhaibar
- Department of Cell Biology, University of Connecticut Health Center, Farmington, CT 06030, USA
| | - Aaron B Edmund
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Dusty A Van Helden
- Department of Pharmacology, University of Minnesota, Minneapolis, MN 55455, USA
| | - Jerid W Robinson
- Department of Pharmacology, University of Minnesota, Minneapolis, MN 55455, USA
| | - Tracy F Uliasz
- Department of Cell Biology, University of Connecticut Health Center, Farmington, CT 06030, USA
| | - Valentina Baena
- Department of Cell Biology, University of Connecticut Health Center, Farmington, CT 06030, USA
| | - Andreas Geerts
- Bayer Pharma AG, Pharma Research Center, Wuppertal D-42096, Germany
| | - Frank Wunder
- Bayer Pharma AG, Pharma Research Center, Wuppertal D-42096, Germany
| | - Lincoln R Potter
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA Department of Pharmacology, University of Minnesota, Minneapolis, MN 55455, USA
| | - Laurinda A Jaffe
- Department of Cell Biology, University of Connecticut Health Center, Farmington, CT 06030, USA
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34
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Hoffmann LS, Chen HH. cGMP: transition from bench to bedside: a report of the 6th International Conference on cGMP Generators, Effectors and Therapeutic Implications. Naunyn Schmiedebergs Arch Pharmacol 2014; 387:707-18. [PMID: 24927824 DOI: 10.1007/s00210-014-0999-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Accepted: 05/30/2014] [Indexed: 02/06/2023]
Abstract
Essential physiological homeostatic processes such as vascular tone, fluid balance, cardiorenal function, and sensory processes are regulated by the second messenger cyclic guanosine 3', 5'-monophosphate (cGMP). Dysregulation of cGMP-dependent pathways plays an important role in cardiovascular diseases such as hypertension, pulmonary hypertension, heart failure, or erectile dysfunction. Thus, the cGMP pathway consisting of the cGMP-generating guanylyl cyclases, protein kinases, and phosphodiesterases (PDE) has evolved to an important drug target and is the focus of a wide variety of research fields ranging from unraveling mechanisms on the molecular level to understanding the regulation of physiological and pathophysiological processes by cGMP. Based on the results from basic and preclinical research, therapeutic drugs have been developed which modulate the cGMP pathway and are investigated in clinical trials. Riociguat, a nitric oxide (NO)-independent soluble guanylyl cyclase stimulator; recombinant B-type natriuretic peptide (BNP); or recombinant atrial natriuretic peptide (ANP) and PDE5 inhibitors are cGMP-modulating drugs that are already available for the treatment of pulmonary hypertension, acute heart failure, and erectile dysfunction, respectively. The latest results from basic to clinical research on cGMP were presented on the 6th International Conference on cGMP in Erfurt, Germany, and are summarized in this article.
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Affiliation(s)
- Linda S Hoffmann
- Institute of Pharmacology and Toxicology, Biomedical Center, University of Bonn, Bonn, Germany,
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