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Thompson KJ, Watson S, Zanato C, Dall'Angelo S, De Nooij JC, Pace‐Bonello B, Shenton FC, Sanger HE, Heinz BA, Broad LM, Grosjean N, McQuillian JR, Dubini M, Pyner S, Greig I, Zanda M, Bleakman D, Banks RW, Bewick GS. The atypical 'hippocampal' glutamate receptor coupled to phospholipase D that controls stretch-sensitivity in primary mechanosensory nerve endings is homomeric purely metabotropic GluK2. Exp Physiol 2024; 109:81-99. [PMID: 37656490 PMCID: PMC10988755 DOI: 10.1113/ep090761] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2022] [Accepted: 08/08/2023] [Indexed: 09/02/2023]
Abstract
A metabotropic glutamate receptor coupled to phospholipase D (PLD-mGluR) was discovered in the hippocampus over three decades ago. Its pharmacology and direct linkage to PLD activation are well established and indicate it is a highly atypical glutamate receptor. A receptor with the same pharmacology is present in spindle primary sensory terminals where its blockade can totally abolish, and its activation can double, the normal stretch-evoked firing. We report here the first identification of this PLD-mGluR protein, by capitalizing on its expression in primary mechanosensory terminals, developing an enriched source, pharmacological profiling to identify an optimal ligand, and then functionalizing it as a molecular tool. Evidence from immunofluorescence, western and far-western blotting indicates PLD-mGluR is homomeric GluK2, since GluK2 is the only glutamate receptor protein/receptor subunit present in spindle mechanosensory terminals. Its expression was also found in the lanceolate palisade ending of hair follicle, also known to contain the PLD-mGluR. Finally, in a mouse model with ionotropic function ablated in the GluK2 subunit, spindle glutamatergic responses were still present, confirming it acts purely metabotropically. We conclude the PLD-mGluR is a homomeric GluK2 kainate receptor signalling purely metabotropically and it is common to other, perhaps all, primary mechanosensory endings.
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Affiliation(s)
- Karen J. Thompson
- Institute of Medical Sciences, School of Medicine, Medical Sciences & NutritionUniversity of AberdeenAberdeenUK
| | - Sonia Watson
- Institute of Medical Sciences, School of Medicine, Medical Sciences & NutritionUniversity of AberdeenAberdeenUK
| | - Chiara Zanato
- Institute of Medical Sciences, School of Medicine, Medical Sciences & NutritionUniversity of AberdeenAberdeenUK
| | - Sergio Dall'Angelo
- Institute of Medical Sciences, School of Medicine, Medical Sciences & NutritionUniversity of AberdeenAberdeenUK
| | | | | | | | | | | | | | - Noelle Grosjean
- CNRS UMR 5297, Interdisciplinary Institute of NeuroscienceUniversity of BordeauxBordeauxFrance
| | - Jessica R. McQuillian
- Institute of Medical Sciences, School of Medicine, Medical Sciences & NutritionUniversity of AberdeenAberdeenUK
| | - Marina Dubini
- Institute of Medical Sciences, School of Medicine, Medical Sciences & NutritionUniversity of AberdeenAberdeenUK
| | - Susan Pyner
- Department of BiosciencesDurham UniversityDurhamUK
| | - Iain Greig
- Institute of Medical Sciences, School of Medicine, Medical Sciences & NutritionUniversity of AberdeenAberdeenUK
| | - Matteo Zanda
- Institute of Medical Sciences, School of Medicine, Medical Sciences & NutritionUniversity of AberdeenAberdeenUK
| | | | | | - Guy S. Bewick
- Institute of Medical Sciences, School of Medicine, Medical Sciences & NutritionUniversity of AberdeenAberdeenUK
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2
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Xiao B, Xiang Q, Deng Z, Chen D, Wu S, Zhang Y, Liang Y, Wei S, Luo G, Li L. KCNN1 promotes proliferation and metastasis of breast cancer via ERLIN2-mediated stabilization and K63-dependent ubiquitination of Cyclin B1. Carcinogenesis 2023; 44:809-823. [PMID: 37831636 PMCID: PMC10818095 DOI: 10.1093/carcin/bgad070] [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: 11/04/2022] [Revised: 09/18/2023] [Accepted: 10/03/2023] [Indexed: 10/15/2023] Open
Abstract
Potassium Calcium-Activated Channel Subfamily N1 (KCNN1), an integral membrane protein, is thought to regulate neuronal excitability by contributing to the slow component of synaptic after hyperpolarization. However, the role of KCNN1 in tumorigenesis has been rarely reported, and the underlying molecular mechanism remains unclear. Here, we report that KCNN1 functions as an oncogene in promoting breast cancer cell proliferation and metastasis. KCNN1 was overexpressed in breast cancer tissues and cells. The pro-proliferative and pro-metastatic effects of KCNN1 were demonstrated by CCK8, clone formation, Edu assay, wound healing assay and transwell experiments. Transcriptomic analysis using KCNN1 overexpressing cells revealed that KCNN1 could regulate key signaling pathways affecting the survival of breast cancer cells. KCNN1 interacts with ERLIN2 and enhances the effect of ERLIN2 on Cyclin B1 stability. Overexpression of KCNN1 promoted the protein expression of Cyclin B1, enhanced its stability and promoted its K63 dependent ubiquitination, while knockdown of KCNN1 had the opposite effects on Cyclin B1. Knockdown (or overexpression) ERLNI2 partially restored Cyclin B1 stability and K63 dependent ubiquitination induced by overexpression (or knockdown) of KCNN1. Knockdown (or overexpression) ERLIN2 also partially neutralizes the effects of overexpression (or knockdown) KCNN1-induced breast cancer cell proliferation, migration and invasion. In paired breast cancer clinical samples, we found a positive expression correlations between KCNN1 and ERLIN2, KCNN1 and Cyclin B1, as well as ERLIN2 and Cyclin B1. In conclusion, this study reveals, for the first time, the role of KCNN1 in tumorigenesis and emphasizes the importance of KCNN1/ERLIN2/Cyclin B1 axis in the development and metastasis of breast cancer.
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Affiliation(s)
- Bin Xiao
- Department of Laboratory Medicine, The Sixth Affiliated Hospital of Guangzhou Medical University, Qingyuan People’s Hospital, Qingyuan, Guangdong 511518, China
| | - Qin Xiang
- Department of Laboratory Medicine, The Sixth Affiliated Hospital of Guangzhou Medical University, Qingyuan People’s Hospital, Qingyuan, Guangdong 511518, China
| | - Zihua Deng
- Department of General Surgery Section 5, The Sixth Affiliated Hospital of Guangzhou Medical University, Qingyuan People’s Hospital, Qingyuan 511518, China
| | - Daxiang Chen
- Department of Laboratory Medicine, The Sixth Affiliated Hospital of Guangzhou Medical University, Qingyuan People’s Hospital, Qingyuan, Guangdong 511518, China
| | - Shunhong Wu
- Department of Laboratory Medicine, The Sixth Affiliated Hospital of Guangzhou Medical University, Qingyuan People’s Hospital, Qingyuan, Guangdong 511518, China
| | - Yanxia Zhang
- Department of Laboratory Medicine, The Sixth Affiliated Hospital of Guangzhou Medical University, Qingyuan People’s Hospital, Qingyuan, Guangdong 511518, China
| | - Yaru Liang
- Department of Laboratory Medicine, The Sixth Affiliated Hospital of Guangzhou Medical University, Qingyuan People’s Hospital, Qingyuan, Guangdong 511518, China
| | - Shi Wei
- Department of Histology and Embryology, School of Basic Medical Sciences, Guangzhou Medical University, Guangzhou, Guangdong, China
| | - Guoqing Luo
- Department of General Surgery Section 5, The Sixth Affiliated Hospital of Guangzhou Medical University, Qingyuan People’s Hospital, Qingyuan 511518, China
| | - Linhai Li
- Department of Laboratory Medicine, The Sixth Affiliated Hospital of Guangzhou Medical University, Qingyuan People’s Hospital, Qingyuan, Guangdong 511518, China
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3
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Wilkinson KA. Molecular determinants of mechanosensation in the muscle spindle. Curr Opin Neurobiol 2022; 74:102542. [PMID: 35430481 PMCID: PMC9815952 DOI: 10.1016/j.conb.2022.102542] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Revised: 01/12/2022] [Accepted: 03/13/2022] [Indexed: 01/11/2023]
Abstract
The muscle spindle (MS) provides essential sensory information for motor control and proprioception. The Group Ia and II MS afferents are low threshold slowly-adapting mechanoreceptors and report both static muscle length and dynamic muscle movement information. The exact molecular mechanism by which MS afferents transduce muscle movement into action potentials is incompletely understood. This short review will discuss recent evidence suggesting that PIEZO2 is an essential mechanically sensitive ion channel in MS afferents and that vesicle-released glutamate contributes to maintaining afferent excitability during the static phase of stretch. Other mechanically gated ion channels, voltage-gated sodium channels, other ion channels, regulatory proteins, and interactions with the intrafusal fibers are also important for MS afferent mechanosensation. Future studies are needed to fully understand mechanosensation in the MS and whether different complements of molecular mediators contribute to the different response properties of Group Ia and II afferents.
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4
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Pang Q, Lin X, Sun J, Hu J, Dai S, Shen Y, Xu M, Xu J. Comprehensive Analysis of Circular RNA Expression in ceRNA Networks and Identification of the Effects of hsa_circ_0006867 in Keloid Dermal Fibroblasts. Front Mol Biosci 2022; 9:800122. [PMID: 35174214 PMCID: PMC8841745 DOI: 10.3389/fmolb.2022.800122] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Accepted: 01/03/2022] [Indexed: 01/07/2023] Open
Abstract
Circular RNAs (circRNAs) play a crucial role in the pathogenesis of various fibrotic diseases, but the potential biological function and expression profile of circRNAs in keloids remain unknown. Herein, microarray technology was applied to detect circRNA expression in four patient-derived keloid dermal fibroblasts (KDFs) and normal dermal fibroblasts (NDFs). A total of 327 differentially expressed (DE) circRNAs (fold change > 1.5, p < 0.05) were identified with 195 upregulated and 132 downregulated circRNAs. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses showed that the upregulated circRNAs were mainly enriched in the cytoskeleton and tight junctions, while the downregulated circRNAs were related to morphogenesis of the epithelium and axonal guidance. To explore the function of DE circRNAs, a circRNA-miRNA-mRNA network, including five circRNAs, nine miRNAs, and 235 correlated mRNAs, was constructed using bioinformatics analyses. The expression of five DE circRNAs was validated by qRT–PCR in 18 pairs of KDFs and NDFs, and hsa_circ_0006867 showed promising regulatory function in keloids in vitro. Silencing hsa_circ_00006867 suppressed the proliferation, migration, and invasion of keloid fibroblasts. RNA-binding protein immunoprecipitation (RIP) assays indicated that hsa_circ_00006867 may serve as a platform for miRNA binding to Argonaute (AGO) 2. In addition, hsa-miR-29a-5p may be a potential target miRNA of hsa_circ_00006867. Taken together, our research provided multiple novel clues to understand the pathophysiologic mechanism of keloids and identified hsa_circ_0006867 as a biomarker of keloids.
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Than K, Kim E, Navarro C, Chu S, Klier N, Occiano A, Ortiz S, Salazar A, Valdespino SR, Villegas NK, Wilkinson KA. Vesicle-released glutamate is necessary to maintain muscle spindle afferent excitability but not dynamic sensitivity in adult mice. J Physiol 2021; 599:2953-2967. [PMID: 33749829 DOI: 10.1113/jp281182] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Accepted: 02/16/2021] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Muscle spindle afferents are slowly adapting low threshold mechanoreceptors that report muscle length and movement information critical for motor control and proprioception. The rapidly adapting cation channel PIEZO2 has been identified as necessary for muscle spindle afferent stretch sensitivity, although the properties of this channel suggest that additional molecular elements are necessary for mediating the complex slowly adapting response of muscle spindle afferents. We report that glutamate increases muscle spindle afferent static sensitivity in an ex vivo mouse muscle nerve preparation, although blocking glutamate packaging into vesicles by the sole vesicular glutamate transporter, VGLUT1, either pharmacologically or by transgenic knockout of one allele of VGLUT1 decreases muscle spindle afferent static but not dynamic sensitivity. Our results confirm that vesicle-released glutamate is an important contributor to maintained muscle spindle afferent excitability and may suggest a therapeutic target for normalizing muscle spindle afferent function. ABSTRACT Muscle spindle afferents are slowly adapting low threshold mechanoreceptors that have both dynamic and static sensitivity to muscle stretch. The exact mechanism by which these neurons translate muscle movement into action potentials is not well understood, although the PIEZO2 mechanically sensitive cation channel is essential for stretch sensitivity. PIEZO2 is rapidly adapting, suggesting the requirement for additional molecular elements to maintain firing during stretch. Spindle afferent sensory endings contain glutamate-filled synaptic-like vesicles that are released in a stretch- and calcium-dependent manner. Previous work has shown that glutamate can increase and a phospholipase-D coupled metabotropic glutamate antagonist can abolish firing during static stretch. Here, we test the hypothesis that vesicle-released glutamate is necessary for maintaining muscle spindle afferent excitability during static but not dynamic stretch. To test this hypothesis, we used a mouse muscle-nerve ex vivo preparation to measure identified muscle spindle afferent responses to stretch and vibration. In C57BL/6 adult mice, bath applied glutamate significantly increased the firing rate during the plateau phase of stretch but not during the dynamic phase of stretch. Blocking the packaging of glutamate into vesicles by the sole vesicular glutamate transporter, VGLUT1, either with xanthurenic acid or by using a transgenic mouse with only one copy of the VGLUT1 gene (VGLUT1+/- ), decreased muscle spindle afferent firing during sustained stretch but not during vibration. Our results suggest a model of mechanotransduction where calcium entering the PIEZO2 channel can cause the release of glutamate from synaptic-like vesicles, which then helps to maintain afferent depolarization and firing.
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Affiliation(s)
- Kimberly Than
- Department of Biological Sciences, San José State University, San Jose, CA, USA
| | - Enoch Kim
- Department of Biological Sciences, San José State University, San Jose, CA, USA
| | - Cebrina Navarro
- Department of Biological Sciences, San José State University, San Jose, CA, USA
| | - Sarah Chu
- Department of Biological Sciences, San José State University, San Jose, CA, USA
| | - Nikola Klier
- Department of Biological Sciences, San José State University, San Jose, CA, USA
| | - Alyssa Occiano
- Department of Biological Sciences, San José State University, San Jose, CA, USA
| | - Serena Ortiz
- Department of Biological Sciences, San José State University, San Jose, CA, USA
| | - Alexandra Salazar
- Department of Biological Sciences, San José State University, San Jose, CA, USA
| | - Steven R Valdespino
- Department of Biological Sciences, San José State University, San Jose, CA, USA
| | - Natanya K Villegas
- Department of Biological Sciences, San José State University, San Jose, CA, USA
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6
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Byers MR. Chewing causes rapid changes in immunoreactive nerve patterns in rat molar teeth: Implications for dental proprioception and pain. Arch Oral Biol 2019; 107:104511. [PMID: 31445382 DOI: 10.1016/j.archoralbio.2019.104511] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 07/19/2019] [Accepted: 07/28/2019] [Indexed: 01/06/2023]
Abstract
OBJECTIVE This study tests the hypothesis that normal use of teeth (chewing) causes changes in immunoreactive-(IR) patterns for endings of large Aβ and CGRP axons in rat molar cusps. DESIGN First, a new paradigm to test chewing in adult male rats was developed. Then IR patterns for large dental axons were analysed for a calcium-binding protein, parvalbumin (PV), heavy neurofilament protein-200 (NFP), and vesicle-release molecule synaptophysin (SYN) that all typify large dental axons and proprioceptors for comparison with endings of CGRP-IR neuropeptide axons. The behavior groups were: (1) daytime sleeping/fasting (Group:SF); (2) brief feeding after 8-11 h of daytime sleeping/fasting (Group:SF-C); (3) normal nocturnal feeding (Group:N); (4) nocturnal fasting (Group:NF); (5) brief feeding/chewing after nocturnal fasting (Group:NF-C). RESULTS Nerve endings with NFP-, PV-, or SYN-IR were lost or altered in pulp and dentin in all chewing groups. Other endings with CGRP-IR were near those with PV-, NFP- and SYN-IR at the pulp-dentin border and in dentin, and they also lost immunoreactivity in all chewing groups. The special beaded regions along the crown pulp/dentin borders lost neural labeling in all chewing groups. Nerves of molar roots and periodontal ligament were not changed. CONCLUSIONS Rapid neural reactions to chewing show extensive, reversible, non-nociceptive depletions of crown innervation. Those changes were rapid enough to occur during normal feeding followed by recovery during rest. The new dental paradigm related to chewing and fasting allows dissection of intradental proprioceptive-like mechanisms during normal tooth functions for comparison with nociceptive and mechanosensitive reactions after injury or inflammation.
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Affiliation(s)
- Margaret R Byers
- Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, WA, 98195-6540 USA.
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7
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Tsubouchi A, Yano T, Yokoyama TK, Murtin C, Otsuna H, Ito K. Topological and modality-specific representation of somatosensory information in the fly brain. Science 2018; 358:615-623. [PMID: 29097543 DOI: 10.1126/science.aan4428] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Accepted: 09/25/2017] [Indexed: 12/11/2022]
Abstract
Insects and mammals share similarities of neural organization underlying the perception of odors, taste, vision, sound, and gravity. We observed that insect somatosensation also corresponds to that of mammals. In Drosophila, the projections of all the somatosensory neuron types to the insect's equivalent of the spinal cord segregated into modality-specific layers comparable to those in mammals. Some sensory neurons innervate the ventral brain directly to form modality-specific and topological somatosensory maps. Ascending interneurons with dendrites in matching layers of the nerve cord send axons that converge to respective brain regions. Pathways arising from leg somatosensory neurons encode distinct qualities of leg movement information and play different roles in ground detection. Establishment of the ground pattern and genetic tools for neuronal manipulation should provide the basis for elucidating the mechanisms underlying somatosensation.
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Affiliation(s)
- Asako Tsubouchi
- Institute of Molecular and Cellular Biosciences, The University of Tokyo, Yayoi, Bunkyo-ku, 113-0032 Tokyo, Japan
| | - Tomoko Yano
- Institute of Molecular and Cellular Biosciences, The University of Tokyo, Yayoi, Bunkyo-ku, 113-0032 Tokyo, Japan.,Department of Computational Biology, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwanoha, Kashiwa, 277-0882 Chiba, Japan
| | - Takeshi K Yokoyama
- Institute of Molecular and Cellular Biosciences, The University of Tokyo, Yayoi, Bunkyo-ku, 113-0032 Tokyo, Japan
| | - Chloé Murtin
- Institute of Molecular and Cellular Biosciences, The University of Tokyo, Yayoi, Bunkyo-ku, 113-0032 Tokyo, Japan.,Department of Computational Biology, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwanoha, Kashiwa, 277-0882 Chiba, Japan
| | - Hideo Otsuna
- Howard Hughes Medical Institute, Janelia Research Campus, Ashburn, VA 20147, USA
| | - Kei Ito
- Institute of Molecular and Cellular Biosciences, The University of Tokyo, Yayoi, Bunkyo-ku, 113-0032 Tokyo, Japan. .,Department of Computational Biology, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwanoha, Kashiwa, 277-0882 Chiba, Japan.,Howard Hughes Medical Institute, Janelia Research Campus, Ashburn, VA 20147, USA.,Institute of Zoology, University of Cologne, 50674 Cologne, Germany
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8
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Narayanan P, Sondermann J, Rouwette T, Karaca S, Urlaub H, Mitkovski M, Gomez-Varela D, Schmidt M. Native Piezo2 Interactomics Identifies Pericentrin as a Novel Regulator of Piezo2 in Somatosensory Neurons. J Proteome Res 2016; 15:2676-87. [PMID: 27345391 DOI: 10.1021/acs.jproteome.6b00235] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The ability of somatosensory neurons to perceive mechanical stimuli relies on specialized mechanotransducing proteins and their molecular environment. Only recently has the identity of a major transducer of mechanical forces in vertebrates been revealed by the discovery of Piezo2. Further work has established its pivotal role for innocuous touch in mice. Therefore, Piezo2 offers a unique platform for the molecular investigation of somatosensory mechanosensation. We performed a mass spectrometry-based interactomics screen on native Piezo2 in somatosensory neurons of mouse dorsal root ganglia (DRG). Stringent and quantitative data analysis yielded the identity of 36 novel binding partners of Piezo2. The biological significance of this data set is reflected by functional experiments demonstrating a role for Pericentrin in modulating Piezo2 activity and membrane expression in somatosensory neurons. Collectively, our findings provide a framework for understanding Piezo2 physiology and serve as a rich resource for the molecular dissection of mouse somatosensation.
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Affiliation(s)
- Pratibha Narayanan
- Max-Planck Institute of Experimental Medicine , Somatosensory Signaling and Systems Biology Group, D-37075 Goettingen, Germany
| | - Julia Sondermann
- Max-Planck Institute of Experimental Medicine , Somatosensory Signaling and Systems Biology Group, D-37075 Goettingen, Germany
| | - Tom Rouwette
- Max-Planck Institute of Experimental Medicine , Somatosensory Signaling and Systems Biology Group, D-37075 Goettingen, Germany
| | - Samir Karaca
- Max Planck Institute of Biophysical Chemistry , Bioanalytical Mass Spectrometry Group, D-37077 Goettingen, Germany
| | - Henning Urlaub
- Max Planck Institute of Biophysical Chemistry , Bioanalytical Mass Spectrometry Group, D-37077 Goettingen, Germany.,Bioanaytics Group, Institute for Clinical Chemistry, University Medical Center Göttingen , D-37075 Göttingen, Germany
| | - Mišo Mitkovski
- Max-Planck Institute of Experimental Medicine , Light Microscopy Facility, D-37075 Goettingen, Germany
| | - David Gomez-Varela
- Max-Planck Institute of Experimental Medicine , Somatosensory Signaling and Systems Biology Group, D-37075 Goettingen, Germany
| | - Manuela Schmidt
- Max-Planck Institute of Experimental Medicine , Somatosensory Signaling and Systems Biology Group, D-37075 Goettingen, Germany
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9
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Bewick GS. Synaptic-like vesicles and candidate transduction channels in mechanosensory terminals. J Anat 2016; 227:194-213. [PMID: 26179025 PMCID: PMC4523322 DOI: 10.1111/joa.12337] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/18/2015] [Indexed: 01/22/2023] Open
Abstract
This article summarises progress to date over an exciting and very enjoyable first 15 years of collaboration with Bob Banks. Our collaboration began when I contacted him with (to me) an unexpected observation that a dye used to mark recycling synaptic vesicle membrane at efferent terminals also labelled muscle spindle afferent terminals. This observation led to the re-discovery of a system of small clear vesicles present in all vertebrate primary mechanosensory nerve terminals. These synaptic-like vesicles (SLVs) have been, and continue to be, the major focus of our work. This article describes our characterisation of the properties and functional significance of these SLVs, combining our complementary skills: Bob’s technical expertise and encyclopaedic knowledge of mechanosensation with my experience of synaptic vesicles and the development of the styryl pyridinium dyes, of which the most widely used is FM1-43. On the way we have found that SLVs seem to be part of a constitutive glutamate secretory system necessary to maintain the stretch-sensitivity of spindle endings. The glutamate activates a highly unusual glutamate receptor linked to phospholipase D activation, which we have termed the PLD-mGluR. It has a totally distinct pharmacology first described in the hippocampus nearly 20 years ago but, like the SLVs that were first described over 50 years ago, has since been little researched. Yet, our evidence and literature searches suggest this glutamate/SLV/PLD-mGluR system is a ubiquitous feature of mechanosensory endings and, at least for spindles, is essential for maintaining mechanosensory function. This article summarises how this system integrates with the classical model of mechanosensitive channels in spindles and other mechanosensory nerve terminals, including hair follicle afferents and baroreceptors controlling blood pressure. Finally, in this time when there is an imperative to show translational relevance, I describe how this fascinating system might actually be a useful therapeutic drug target for clinical conditions such as hypertension and muscle spasticity. This has been a fascinating 15-year journey in collaboration with Bob who, as well as having an astute scientific mind, is also a great enthusiast, motivator and friend. I hope this exciting and enjoyable journey will continue well into the future.
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Affiliation(s)
- Guy S Bewick
- School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Aberdeen, UK
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10
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Bewick GS, Banks RW. Optical Monitoring of Living Nerve Terminal Labeling in Hair Follicle Lanceolate Endings of the Ex Vivo Mouse Ear Skin. J Vis Exp 2016:e53855. [PMID: 27077818 PMCID: PMC4841365 DOI: 10.3791/53855] [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] [Indexed: 10/31/2022] Open
Abstract
A novel dissection and recording technique is described for optical monitoring staining and de-staining of lanceolate terminals surrounding hair follicles in the skin of the mouse pinna. The preparation is simple and relatively fast, reliably yielding extensive regions of multiple labeled units of living nerve terminals to study uptake and release of styryl pyridinium dyes extensively used in studies of vesicle recycling. Subdividing the preparations before labeling allows test vs. control comparisons in the same ear from a single individual. Helpful tips are given for improving the quality of the preparation, the labeling and the imaging parameters. This new system is suitable for assaying pharmacologically and mechanically-induced uptake and release of these vital dyes in lanceolate terminals in both wild-type and genetically modified animals. Examples of modulatory influences on labeling intensity are given.
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Affiliation(s)
- Guy S Bewick
- School of Medical Sciences, University of Aberdeen;
| | - Robert W Banks
- School of Biological & Biomedical Sciences, University of Durham
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11
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Ribchester RR. Some reminiscences on studies of age-dependent and activity-dependent degeneration of sensory and motor endings in mammalian skeletal muscle. J Anat 2015; 227:231-6. [PMID: 26179026 PMCID: PMC4523325 DOI: 10.1111/joa.12334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/29/2015] [Indexed: 11/29/2022] Open
Abstract
I present here an overview of research on the biology of neuromuscular sensory and motor endings that was inspired and influenced partly by my educational experience in the Department of Zoology at the University of Durham, from 1971 to 1974. I allude briefly to neuromuscular synaptic structure and function in dystrophic mice, influences of activity on synapse elimination in development and regeneration, and activity-dependent protection and degeneration of neuromuscular junctions in WldS mice.
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Affiliation(s)
- Richard R Ribchester
- Euan MacDonald Centre for Motor Neurone Disease Research and Centre for Integrative Physiology, University of Edinburgh, George Square, Edinburgh, UK
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12
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Vincent JA, Nardelli P, Gabriel HM, Deardorff AS, Cope TC. Complex impairment of IA muscle proprioceptors following traumatic or neurotoxic injury. J Anat 2015; 227:221-30. [PMID: 26047324 DOI: 10.1111/joa.12312] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/12/2015] [Indexed: 01/09/2023] Open
Abstract
The health of primary sensory afferents supplying muscle has to be a first consideration in assessing deficits in proprioception and related motor functions. Here we discuss the role of a particular proprioceptor, the IA muscle spindle proprioceptor in causing movement disorders in response to either regeneration of a sectioned peripheral nerve or damage from neurotoxic chemotherapy. For each condition, there is a single preferred and widely repeated explanation for disability of movements associated with proprioceptive function. We present a mix of published and preliminary findings from our laboratory, largely from in vivo electrophysiological study of treated rats to demonstrate newly discovered IA afferent defects that seem likely to make important contributions to movement disorders. First, we argue that reconnection of regenerated IA afferents with inappropriate targets, although often repeated as the reason for lost stretch-reflex contraction, is not a complete explanation. We present evidence that despite successful recovery of stretch-evoked sensory signaling, peripherally regenerated IA afferents retract synapses made with motoneurons in the spinal cord. Second, we point to evidence that movement disability suffered by human subjects months after discontinuation of oxaliplatin (OX) chemotherapy for some is not accompanied by peripheral neuropathy, which is the acknowledged primary cause of disability. Our studies of OX-treated rats suggest a novel additional explanation in showing the loss of sustained repetitive firing of IA afferents during static muscle stretch. Newly extended investigation reproduces this effect in normal rats with drugs that block Na(+) channels apparently involved in encoding static IA afferent firing. Overall, these findings highlight multiplicity in IA afferent deficits that must be taken into account in understanding proprioceptive disability, and that present new avenues and possible advantages for developing effective treatment. Extending the study of IA afferent deficits yielded the additional benefit of elucidating normal processes in IA afferent mechanosensory function.
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Affiliation(s)
- Jacob A Vincent
- Department of Neuroscience, Cell Biology and Physiology, Wright State University, Dayton, OH, USA
| | - Paul Nardelli
- Department of Neuroscience, Cell Biology and Physiology, Wright State University, Dayton, OH, USA
| | - Hanna M Gabriel
- Department of Neuroscience, Cell Biology and Physiology, Wright State University, Dayton, OH, USA
| | - Adam S Deardorff
- Department of Neuroscience, Cell Biology and Physiology, Wright State University, Dayton, OH, USA
| | - Timothy C Cope
- Department of Neuroscience, Cell Biology and Physiology, Wright State University, Dayton, OH, USA
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Taylor-Clark TE, Wu KY, Thompson JA, Yang K, Bahia PK, Ajmo JM. Thy1.2 YFP-16 transgenic mouse labels a subset of large-diameter sensory neurons that lack TRPV1 expression. PLoS One 2015; 10:e0119538. [PMID: 25746468 PMCID: PMC4351979 DOI: 10.1371/journal.pone.0119538] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Accepted: 01/21/2015] [Indexed: 11/18/2022] Open
Abstract
The Thy1.2 YFP-16 mouse expresses yellow fluorescent protein (YFP) in specific subsets of peripheral and central neurons. The original characterization of this model suggested that YFP was expressed in all sensory neurons, and this model has been subsequently used to study sensory nerve structure and function. Here, we have characterized the expression of YFP in the sensory ganglia (DRG, trigeminal and vagal) of the Thy1.2 YFP-16 mouse, using biochemical, functional and anatomical analyses. Despite previous reports, we found that YFP was only expressed in approximately half of DRG and trigeminal neurons and less than 10% of vagal neurons. YFP-expression was only found in medium and large-diameter neurons that expressed neurofilament but not TRPV1. YFP-expressing neurons failed to respond to selective agonists for TRPV1, P2X(2/3 and TRPM8 channels in Ca2+ imaging assays. Confocal analysis of glabrous skin, hairy skin of the back and ear and skeletal muscle indicated that YFP was expressed in some peripheral terminals with structures consistent with their presumed non-nociceptive nature. In summary, the Thy1.2 YFP-16 mouse expresses robust YFP expression in only a subset of sensory neurons. But this mouse model is not suitable for the study of nociceptive nerves or the function of such nerves in pain and neuropathies.
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Affiliation(s)
- Thomas E. Taylor-Clark
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida, United States of America
- * E-mail:
| | - Kevin Y. Wu
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida, United States of America
| | - Julie-Ann Thompson
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida, United States of America
| | - Kiseok Yang
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida, United States of America
| | - Parmvir K. Bahia
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida, United States of America
| | - Joanne M. Ajmo
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, Florida, United States of America
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