1
|
Luo Y, Wang Y, Qiu F, Hou G, Liu J, Yang H, Wu M, Dong X, Guo D, Zhong Z, Zhang X, Ge J, Meng P. Ablated Sonic Hedgehog Signaling in the Dentate Gyrus of the Dorsal and Ventral Hippocampus Impairs Hippocampal-Dependent Memory Tasks and Emotion in a Rat Model of Depression. Mol Neurobiol 2024; 61:4352-4368. [PMID: 38087166 DOI: 10.1007/s12035-023-03796-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Accepted: 11/08/2023] [Indexed: 07/11/2024]
Abstract
Specific memory processes and emotional aberrations in depression can be attributed to the different dorsal-ventral regions of the hippocampus. However, the molecular mechanisms underlying the differential functions of the dorsal hippocampus (dHip) and ventral hippocampus (vHip) remain unclear. As Sonic Hedgehog (Shh) is involved in the dorsal-ventral patterning of the neural tube and its signaling is dysregulated by chronic unpredictable mild stress (CUMS), we investigated its role in influencing the differential functions of the dHip and vHip. Here, CUMS downregulated the expression of Shh signaling markers, including Shh and its downstream effectors GLI family zinc finger 12 (Gli1/2), Patched (Ptch), and smoothened (Smo), in both the dHip and vHip of rats, though more so in the vHip. Additionally, Shh knockdown in the dorsal or ventral dentate gyrus (DG) resulted in restrained neurogenic activity in newborn neurons, especially in immature neurons through decreased expression of Shh signaling markers. Furthermore, Shh knockdown in the DG of the dHip led to memory impairment by inhibiting experience-dependent activation of immature neurons, whereas its knockdown in the DG of the vHip led to an emotional handicap by delaying the maturation of immature neurons. Finally, Shh knockdown in either the dDG or vDG of hippocampus abolished the corresponding cognitive enhancement and emotional recovery of fluoxetine. In conclusion, Shh is essential to maintain the functional heterogeneity of dHip and vHip in depressed rat, which was mainly mediating by local changes of dependent activation and maturity of immature neurons, respectively.
Collapse
Affiliation(s)
- Yan Luo
- Hunan University of Chinese Medicine, Changsha, 410208, Hunan, China
| | - Yan Wang
- Yiyang Central Hospital, Yiyang, 413000, Hunan, China
| | - Feng Qiu
- Hunan University of Chinese Medicine, Changsha, 410208, Hunan, China
| | - Guanghan Hou
- Fourth Hospital of Changsha, Hunan, 410000, China
| | - Jian Liu
- Hunan University of Chinese Medicine, Changsha, 410208, Hunan, China
- First Affiliated Hospital, Hunan University of Chinese Medicine, Changsha, 410007, Hunan, China
| | - Hui Yang
- Hunan University of Chinese Medicine, Changsha, 410208, Hunan, China
- First Affiliated Hospital, Hunan University of Chinese Medicine, Changsha, 410007, Hunan, China
| | - Mei Wu
- Hunan University of Chinese Medicine, Changsha, 410208, Hunan, China
| | - Xuanqi Dong
- The Second People's Hospital of Hunan Province, Changsha, 410000, Hunan, China
| | - Dongwei Guo
- The Second People's Hospital of Hunan Province, Changsha, 410000, Hunan, China
| | - Ziyan Zhong
- Hunan University of Chinese Medicine, Changsha, 410208, Hunan, China
| | - Xi Zhang
- The Second People's Hospital of Hunan Province, Changsha, 410000, Hunan, China.
| | - Jinwen Ge
- Hunan Academy of Chinese Medicine, Changsha, 410300, Hunan, China.
| | - Pan Meng
- Hunan University of Chinese Medicine, Changsha, 410208, Hunan, China.
| |
Collapse
|
2
|
Delmotte Q, Hamze M, Medina I, Buhler E, Zhang J, Belgacem YH, Porcher C. Smoothened receptor signaling regulates the developmental shift of GABA polarity in rat somatosensory cortex. J Cell Sci 2020; 133:jcs247700. [PMID: 32989040 PMCID: PMC7595691 DOI: 10.1242/jcs.247700] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Accepted: 09/12/2020] [Indexed: 02/05/2023] Open
Abstract
Sonic hedgehog (Shh) and its patched-smoothened receptor complex control a variety of functions in the developing central nervous system, such as neural cell proliferation and differentiation. Recently, Shh signaling components have been found to be expressed at the synaptic level in the postnatal brain, suggesting a potential role in the regulation of synaptic transmission. Using in utero electroporation of constitutively active and negative-phenotype forms of the Shh signal transducer smoothened (Smo), we studied the role of Smo signaling in the development and maturation of GABAergic transmission in the somatosensory cortex. Our results show that enhancing Smo activity during development accelerates the shift from depolarizing to hyperpolarizing GABA in a manner dependent on functional expression of potassium-chloride cotransporter type 2 (KCC2, also known as SLC12A5). On the other hand, blocking Smo activity maintains the GABA response in a depolarizing state in mature cortical neurons, resulting in altered chloride homeostasis and increased seizure susceptibility. This study reveals unexpected functions of Smo signaling in the regulation of chloride homeostasis, through control of KCC2 cell-surface stability, and the timing of the GABA excitatory-to-inhibitory shift in brain maturation.
Collapse
Affiliation(s)
- Quentin Delmotte
- Aix-Marseille University, Parc Scientifique de Luminy, 13273, Marseille, France
- INSERM (Institut National de la Santé et de la Recherche Médicale) Unité 1249, Marseille, Parc Scientifique de Luminy, 13273 Marseille, France
- INMED (Institut de Neurobiologie de la Méditerranée), Parc Scientifique de Luminy, 13273 Marseille, France
| | - Mira Hamze
- Aix-Marseille University, Parc Scientifique de Luminy, 13273, Marseille, France
- INSERM (Institut National de la Santé et de la Recherche Médicale) Unité 1249, Marseille, Parc Scientifique de Luminy, 13273 Marseille, France
- INMED (Institut de Neurobiologie de la Méditerranée), Parc Scientifique de Luminy, 13273 Marseille, France
| | - Igor Medina
- Aix-Marseille University, Parc Scientifique de Luminy, 13273, Marseille, France
- INSERM (Institut National de la Santé et de la Recherche Médicale) Unité 1249, Marseille, Parc Scientifique de Luminy, 13273 Marseille, France
- INMED (Institut de Neurobiologie de la Méditerranée), Parc Scientifique de Luminy, 13273 Marseille, France
| | - Emmanuelle Buhler
- INSERM (Institut National de la Santé et de la Recherche Médicale) Unité 1249, Marseille, Parc Scientifique de Luminy, 13273 Marseille, France
- Plateforme Post-Génomique, INMED, 13273 Marseille, France
| | - Jinwei Zhang
- Institute of Biomedical and Clinical Sciences, Medical School, College of Medicine and Health, University of Exeter, Hatherly Laboratories, Exeter EX4 4PS, UK
| | - Yesser H Belgacem
- INSERM (Institut National de la Santé et de la Recherche Médicale) Unité 1249, Marseille, Parc Scientifique de Luminy, 13273 Marseille, France
- INMED (Institut de Neurobiologie de la Méditerranée), Parc Scientifique de Luminy, 13273 Marseille, France
| | - Christophe Porcher
- Aix-Marseille University, Parc Scientifique de Luminy, 13273, Marseille, France
- INSERM (Institut National de la Santé et de la Recherche Médicale) Unité 1249, Marseille, Parc Scientifique de Luminy, 13273 Marseille, France
- INMED (Institut de Neurobiologie de la Méditerranée), Parc Scientifique de Luminy, 13273 Marseille, France
| |
Collapse
|
3
|
Suciu SK, Caspary T. Cilia, neural development and disease. Semin Cell Dev Biol 2020; 110:34-42. [PMID: 32732132 DOI: 10.1016/j.semcdb.2020.07.014] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 07/17/2020] [Accepted: 07/18/2020] [Indexed: 12/16/2022]
Abstract
Neural development requires a series of cellular events starting with cell specification, proliferation, and migration. Subsequently, axons and dendrites project from the cell surface to form connections to other neurons, interneurons and glia. Anomalies in any one of these steps can lead to malformation or malfunction of the nervous system. Here we review the critical role the primary cilium plays in the fundamental steps of neurodevelopment. By highlighting human diseases caused by mutations in cilia-associated proteins, it is clear that cilia are essential to multiple neural processes. Furthermore, we explore whether additional aspects of cilia regulation, most notably post-translational modification of the tubulin scaffold in cilia, play underappreciated roles in neural development. Finally, we discuss whether cilia-associated proteins function outside the cilium in some aspects of neurodevelopment. These data underscore both the importance of cilia in the nervous system and some outstanding questions in the field.
Collapse
Affiliation(s)
- Sarah K Suciu
- Genetics and Molecular Biology Graduate Program, USA; Department of Human Genetics, Emory University, Atlanta, GA 30322, Georgia
| | - Tamara Caspary
- Department of Human Genetics, Emory University, Atlanta, GA 30322, Georgia.
| |
Collapse
|
4
|
Delmotte Q, Diabira D, Belaidouni Y, Hamze M, Kochmann M, Montheil A, Gaiarsa JL, Porcher C, Belgacem YH. Sonic Hedgehog Signaling Agonist (SAG) Triggers BDNF Secretion and Promotes the Maturation of GABAergic Networks in the Postnatal Rat Hippocampus. Front Cell Neurosci 2020; 14:98. [PMID: 32425757 PMCID: PMC7212340 DOI: 10.3389/fncel.2020.00098] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Accepted: 03/31/2020] [Indexed: 12/13/2022] Open
Abstract
Sonic hedgehog (Shh) signaling plays critical roles during early central nervous system development, such as neural cell proliferation, patterning of the neural tube and neuronal differentiation. While Shh signaling is still present in the postnatal brain, the roles it may play are, however, largely unknown. In particular, Shh signaling components are found at the synaptic junction in the maturing hippocampus during the first two postnatal weeks. This period is characterized by the presence of ongoing spontaneous synaptic activity at the cellular and network levels thought to play important roles in the onset of neuronal circuit formation and synaptic plasticity. Here, we demonstrate that non-canonical Shh signaling increases the frequency of the synchronized electrical activity called Giant Depolarizing Potentials (GDP) and enhances spontaneous GABA post-synaptic currents in the rodent hippocampus during the early postnatal period. This effect is mediated specifically through the Shh co-receptor Smoothened via intracellular Ca2+ signal and the activation of the BDNF-TrkB signaling pathway. Given the importance of these spontaneous events on neuronal network maturation and refinement, this study opens new perspectives for Shh signaling on the control of early stages of postnatal brain maturation and physiology.
Collapse
Affiliation(s)
- Quentin Delmotte
- Aix-Marseille Univ, Marseille, France.,INSERM (Institut National de la Santé et de la Recherche Médicale) Unité 1249, Marseille, France.,INMED (Institut de Neurobiologie de la Méditerranée), Parc Scientifique de Luminy, Marseille, France
| | - Diabe Diabira
- INSERM (Institut National de la Santé et de la Recherche Médicale) Unité 1249, Marseille, France.,INMED (Institut de Neurobiologie de la Méditerranée), Parc Scientifique de Luminy, Marseille, France
| | - Yasmine Belaidouni
- Aix-Marseille Univ, Marseille, France.,INSERM (Institut National de la Santé et de la Recherche Médicale) Unité 1249, Marseille, France.,INMED (Institut de Neurobiologie de la Méditerranée), Parc Scientifique de Luminy, Marseille, France
| | - Mira Hamze
- Aix-Marseille Univ, Marseille, France.,INSERM (Institut National de la Santé et de la Recherche Médicale) Unité 1249, Marseille, France.,INMED (Institut de Neurobiologie de la Méditerranée), Parc Scientifique de Luminy, Marseille, France
| | - Marine Kochmann
- Aix-Marseille Univ, Marseille, France.,Institut des Neurosciences de La Timone, Marseille, France
| | - Aurélie Montheil
- Aix-Marseille Univ, Marseille, France.,INSERM (Institut National de la Santé et de la Recherche Médicale) Unité 1249, Marseille, France.,INMED (Institut de Neurobiologie de la Méditerranée), Parc Scientifique de Luminy, Marseille, France
| | - Jean-Luc Gaiarsa
- Aix-Marseille Univ, Marseille, France.,INSERM (Institut National de la Santé et de la Recherche Médicale) Unité 1249, Marseille, France.,INMED (Institut de Neurobiologie de la Méditerranée), Parc Scientifique de Luminy, Marseille, France
| | - Christophe Porcher
- Aix-Marseille Univ, Marseille, France.,INSERM (Institut National de la Santé et de la Recherche Médicale) Unité 1249, Marseille, France.,INMED (Institut de Neurobiologie de la Méditerranée), Parc Scientifique de Luminy, Marseille, France
| | - Yesser H Belgacem
- INSERM (Institut National de la Santé et de la Recherche Médicale) Unité 1249, Marseille, France.,INMED (Institut de Neurobiologie de la Méditerranée), Parc Scientifique de Luminy, Marseille, France
| |
Collapse
|
5
|
Liu D, Bai X, Ma W, Xin D, Chu X, Yuan H, Qiu J, Ke H, Yin S, Chen W, Wang Z. Purmorphamine Attenuates Neuro-Inflammation and Synaptic Impairments After Hypoxic-Ischemic Injury in Neonatal Mice via Shh Signaling. Front Pharmacol 2020; 11:204. [PMID: 32194421 PMCID: PMC7064623 DOI: 10.3389/fphar.2020.00204] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Accepted: 02/14/2020] [Indexed: 01/05/2023] Open
Abstract
Purmorphamine (PUR), an agonist of the Smoothened (Smo) receptor, has been shown to function as a neuroprotectant in acute experimental ischemic stroke. Its role in hypoxic-ischemic (HI) brain injury in neonatal mice remains unknown. Here we show that PUR attenuated acute brain injury, with a decrease in Bax/Bcl-2 ratio as well as inhibition of caspase-3 activation. These beneficial effects of PUR were associated with suppressing neuro-inflammation and oxidative stress. PUR exerted long-term protective effects upon tissue loss and improved neurobehavioral outcomes as determined at 14 and 28 days post-HI insult. Moreover, PUR increased synaptophysin (Syn) and postsynaptic density (PSD) protein 95 expression in HI-treated mice and attenuated synaptic loss. PUR upregulated the expression of Shh pathway mediators, while suppression of the Shh signaling pathway with cyclopamine (Cyc) reversed these beneficial effects of PUR on HI insult. Our study suggests a therapeutic potential for short-term PUR administration in HI-induced injury as a result of its capacity to exert multiple protective actions upon acute brain injury, long-term memory deficits, and impaired synapses. Moreover, we provide evidence indicating that one of the mechanisms underlying these beneficial effects of PUR involves activation of the Shh signaling pathway.
Collapse
Affiliation(s)
- Dexiang Liu
- Department of Medical Psychology and Ethics, School of Basic Medicine Sciences, Shandong University, Jinan, China
| | - Xuemei Bai
- Department of Physiology, School of Basic Medical Sciences, Shandong University, Jinan, China
| | - Weiwei Ma
- Department of Medical Psychology and Ethics, School of Basic Medicine Sciences, Shandong University, Jinan, China.,Department of Physiology, School of Basic Medical Sciences, Shandong University, Jinan, China
| | - Danqing Xin
- Department of Physiology, School of Basic Medical Sciences, Shandong University, Jinan, China
| | - Xili Chu
- Department of Physiology, School of Basic Medical Sciences, Shandong University, Jinan, China
| | - Hongtao Yuan
- Department of Physiology, School of Basic Medical Sciences, Shandong University, Jinan, China
| | - Jie Qiu
- Department of Medical Psychology and Ethics, School of Basic Medicine Sciences, Shandong University, Jinan, China.,Department of Physiology, School of Basic Medical Sciences, Shandong University, Jinan, China
| | - HongFei Ke
- Department of Physiology, School of Basic Medical Sciences, Shandong University, Jinan, China
| | - Sen Yin
- Qilu Hospital, Shandong University, Jinan, China
| | | | - Zhen Wang
- Department of Physiology, School of Basic Medical Sciences, Shandong University, Jinan, China
| |
Collapse
|
6
|
Canterini S, Dragotto J, Dardis A, Zampieri S, De Stefano ME, Mangia F, Erickson RP, Fiorenza MT. Shortened primary cilium length and dysregulated Sonic hedgehog signaling in Niemann-Pick C1 disease. Hum Mol Genet 2017; 26:2277-2289. [DOI: 10.1093/hmg/ddx118] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Accepted: 03/25/2017] [Indexed: 11/13/2022] Open
|
7
|
Sonic -'Jack-of-All-Trades' in Neural Circuit Formation. J Dev Biol 2017; 5:jdb5010002. [PMID: 29615560 PMCID: PMC5831768 DOI: 10.3390/jdb5010002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Revised: 01/22/2017] [Accepted: 02/01/2017] [Indexed: 12/23/2022] Open
Abstract
As reflected by the term morphogen, molecules such as Shh and Wnts were identified based on their role in early development when they instruct precursor cells to adopt a specific cell fate. Only much later were they implicated in neural circuit formation. Both in vitro and in vivo studies indicated that morphogens direct axons during their navigation through the developing nervous system. Today, the best understood role of Shh and Wnt in axon guidance is their effect on commissural axons in the spinal cord. Shh was shown to affect commissural axons both directly and indirectly via its effect on Wnt signaling. In fact, throughout neural circuit formation there is cross-talk and collaboration of Shh and Wnt signaling. Thus, although the focus of this review is on the role of Shh in neural circuit formation, a separation from Wnt signaling is not possible.
Collapse
|
8
|
Yao PJ, Petralia RS, Mattson MP. Sonic Hedgehog Signaling and Hippocampal Neuroplasticity. Trends Neurosci 2016; 39:840-850. [PMID: 27865563 PMCID: PMC5148655 DOI: 10.1016/j.tins.2016.10.001] [Citation(s) in RCA: 84] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Revised: 09/22/2016] [Accepted: 10/13/2016] [Indexed: 12/21/2022]
Abstract
Sonic hedgehog (Shh) is a secreted protein that controls the patterning of neural progenitor cells, and their neuronal and glial progeny, during development. Emerging findings suggest that Shh also has important roles in the formation and plasticity of neuronal circuits in the hippocampus, a brain region of fundamental importance in learning and memory. Shh mediates activity-dependent and injury-induced hippocampal neurogenesis. Activation of Shh receptors in the dendrites of hippocampal neurons engages a trans-neuronal signaling pathway that accelerates axon outgrowth and enhances glutamate release from presynaptic terminals. Impaired Shh signaling may contribute to the pathogenesis of several developmental and adult-onset neurological disorders that affect the hippocampus, suggesting a potential for therapeutic interventions that target Shh pathways.
Collapse
Affiliation(s)
- Pamela J Yao
- Laboratory of Neurosciences, National Institute on Aging, Intramural Research Program, Baltimore, MD 21224, USA.
| | - Ronald S Petralia
- Advanced Imaging Core, NIDCD, National Institutes of Health, Bethesda, MD 20892, USA
| | - Mark P Mattson
- Laboratory of Neurosciences, National Institute on Aging, Intramural Research Program, Baltimore, MD 21224, USA; Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
| |
Collapse
|
9
|
Eitan E, Petralia RS, Wang YX, Indig FE, Mattson MP, Yao PJ. Probing extracellular Sonic hedgehog in neurons. Biol Open 2016; 5:1086-92. [PMID: 27387534 PMCID: PMC5004615 DOI: 10.1242/bio.019422] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Accepted: 06/20/2016] [Indexed: 01/02/2023] Open
Abstract
The bioactivity of Sonic hedgehog (Shh) depends on specific lipid modifications; a palmitate at its N-terminus and a cholesterol at its C-terminus. This dual-lipid modification makes Shh molecules lipophilic, which prevents them from diffusing freely in extracellular space. Multiple lines of evidence indicate that Shh proteins are carried by various forms of extracellular vesicles (EVs). It also has been shown, for instance, that in some tissues Shh proteins are transported to neighboring cells directly via filopodia. We have previously reported that Shh proteins are expressed in hippocampal neurons. In this study we show that, in the hippocampus and cerebellum of postnatal day (P)2 rats, Shh is mostly found near or on the membrane surface of small neurites or filopodia. We also examined cultured hippocampal neurons where we observed noticeable and widespread Shh-immunolabeled vesicles located outside neurons. Through immunoelectron microscopy and biochemical analysis, we find Shh-containing EVs with a wide range of sizes. Unlike robust Shh activity in EVs isolated from cells overexpressing an N-terminal Shh fragment construct, we did not detect measurable Shh activity in EVs purified from the medium of cultured hippocampal neurons. These results suggest the complexity of the transcellular Shh signaling mechanisms in neurons.
Collapse
Affiliation(s)
- Erez Eitan
- Laboratory of Neurosciences, National Institute on Aging Intramural Research Program, Baltimore, MD 21224, USA
| | | | - Ya-Xian Wang
- Advanced Imaging Core, NIDCD/NIH, Bethesda, MD 20892, USA
| | - Fred E Indig
- Confocal Imaging Facility, Laboratory of Clinical Investigation, National Institute on Aging Intramural Research Program, Baltimore, MD 21224, USA
| | - Mark P Mattson
- Laboratory of Neurosciences, National Institute on Aging Intramural Research Program, Baltimore, MD 21224, USA
| | - Pamela J Yao
- Laboratory of Neurosciences, National Institute on Aging Intramural Research Program, Baltimore, MD 21224, USA
| |
Collapse
|
10
|
De Luca A, Parmigiani E, Tosatto G, Martire S, Hoshino M, Buffo A, Leto K, Rossi F. Exogenous Sonic hedgehog modulates the pool of GABAergic interneurons during cerebellar development. THE CEREBELLUM 2015; 14:72-85. [PMID: 25245619 DOI: 10.1007/s12311-014-0596-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
All cerebellar GABAergic interneurons were derived from a common pool of precursor cells residing in the embryonic ventricular zone (VZ) and migrating in the prospective white matter (PWM) after birth, where both intrinsic and extrinsic factors contribute to regulate their amplification. Among the environmental factors, we focused on Sonic hedgehog (Shh), a morphogen well known to regulate neural progenitor cell proliferation. We asked if and how exogenous Shh treatment affects the lineage of cerebellar GABAergic interneurons. To address these issues, exogenous Shh was administered to embryonic and postnatal organotypic slices. We found that Shh is able to expand the pool of interneuron progenitors residing in the embryonic epithelium and in the postnatal PWM. In particular, Shh signalling pathway was highly mitogenic at early developmental stages of interneuron production, whereas its effect decreased after the first postnatal week. Gene expression analysis of sorted cells and in situ hybridization further showed that immature interneurons express both the Shh receptor patched and the Shh target gene Gli1. Thus, within the interneuron lineage, Shh might exert regulatory functions also in postmitotic cells. On the whole, our data enlighten the role of Shh during cerebellar maturation and further broaden our knowledge on the amplification mechanisms of the interneuron progenitor pool.
Collapse
Affiliation(s)
- A De Luca
- Department of Neuroscience Rita Levi Montalcini, University of Turin, via Cherasco 15, 10026, Turin, Italy
| | | | | | | | | | | | | | | |
Collapse
|
11
|
Structure, Distribution, and Function of Neuronal/Synaptic Spinules and Related Invaginating Projections. Neuromolecular Med 2015; 17:211-40. [PMID: 26007200 DOI: 10.1007/s12017-015-8358-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Accepted: 05/08/2015] [Indexed: 10/23/2022]
Abstract
Neurons and especially their synapses often project long thin processes that can invaginate neighboring neuronal or glial cells. These "invaginating projections" can occur in almost any combination of postsynaptic, presynaptic, and glial processes. Invaginating projections provide a precise mechanism for one neuron to communicate or exchange material exclusively at a highly localized site on another neuron, e.g., to regulate synaptic plasticity. The best-known types are postsynaptic projections called "spinules" that invaginate into presynaptic terminals. Spinules seem to be most prevalent at large very active synapses. Here, we present a comprehensive review of all kinds of invaginating projections associated with both neurons in general and more specifically with synapses; we describe them in all animals including simple, basal metazoans. These structures may have evolved into more elaborate structures in some higher animal groups exhibiting greater synaptic plasticity. In addition to classic spinules and filopodial invaginations, we describe a variety of lesser-known structures such as amphid microvilli, spinules in giant mossy terminals and en marron/brush synapses, the highly specialized fish retinal spinules, the trophospongium, capitate projections, and fly gnarls, as well as examples in which the entire presynaptic or postsynaptic process is invaginated. These various invaginating projections have evolved to modify the function of a particular synapse, or to channel an effect to one specific synapse or neuron, without affecting those nearby. We discuss how they function in membrane recycling, nourishment, and cell signaling and explore how they might change in aging and disease.
Collapse
|
12
|
Techlovská Š, Chambers JN, Dvořáková M, Petralia RS, Wang YX, Hájková A, Nová A, Franková D, Prezeau L, Blahos J. Metabotropic glutamate receptor 1 splice variants mGluR1a and mGluR1b combine in mGluR1a/b dimers in vivo. Neuropharmacology 2014; 86:329-336. [PMID: 25158311 DOI: 10.1016/j.neuropharm.2014.08.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Revised: 08/13/2014] [Accepted: 08/14/2014] [Indexed: 02/03/2023]
Abstract
The assembly of two covalently linked monomers into dimeric complexes is a prerequisite for metabotropic glutamate receptor 1 (mGluR1) function. The former concept of a strictly homodimeric subunit contribution in metabotropic glutamate receptor complexes has recently been brought into question. Alternative splicing of the GRM1 gene results in expression of variants that vary within their intracellular C-termini. Here we bring evidence that the short mGluR1b variant is found preferentially in a complex with the long mGluR1a variant in the rodent brain. The mGluR1a and mGluR1b variants distribution overlaps in Purkinje cells and the two variants colocalize in their spines. However mGluR1a and mGluR1b show distinct sub-cellular localization when expressed alone in neurons. We discovered that trafficking of mGluR1b to distal dendrites is reliant on its association with mGluR1a and that the long C-terminus of mGluR1a within the mGluR1a/b dimer is necessary for trafficking of the complex.
Collapse
Affiliation(s)
- Šárka Techlovská
- Institute of Molecular Genetics, Academy of Science of the Czech Republic, Videnska 1083, 14220 Prague 4, Czech Republic
| | - Jayne Nicole Chambers
- Institute of Molecular Genetics, Academy of Science of the Czech Republic, Videnska 1083, 14220 Prague 4, Czech Republic
| | - Michaela Dvořáková
- Institute of Molecular Genetics, Academy of Science of the Czech Republic, Videnska 1083, 14220 Prague 4, Czech Republic
| | - Ronald S Petralia
- National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, Maryland 20892
| | - Ya-Xian Wang
- National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, Maryland 20892
| | - Alena Hájková
- Institute of Molecular Genetics, Academy of Science of the Czech Republic, Videnska 1083, 14220 Prague 4, Czech Republic
| | - Alice Nová
- Institute of Molecular Genetics, Academy of Science of the Czech Republic, Videnska 1083, 14220 Prague 4, Czech Republic
| | - Daniela Franková
- Institute of Molecular Genetics, Academy of Science of the Czech Republic, Videnska 1083, 14220 Prague 4, Czech Republic
| | - Laurent Prezeau
- CNRS UMR5203, Institut de génomique fonctionnelle, Montpellier, France.,INSERM U661, Montpellier, France.,Université Montpellier 1 & 2, Montpellier F-34000, France
| | - Jaroslav Blahos
- Institute of Molecular Genetics, Academy of Science of the Czech Republic, Videnska 1083, 14220 Prague 4, Czech Republic
| |
Collapse
|
13
|
He S, Wang YX, Petralia RS, Brenowitz SD. Cholinergic modulation of large-conductance calcium-activated potassium channels regulates synaptic strength and spine calcium in cartwheel cells of the dorsal cochlear nucleus. J Neurosci 2014; 34:5261-72. [PMID: 24719104 PMCID: PMC3983802 DOI: 10.1523/jneurosci.3728-13.2014] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2013] [Revised: 02/05/2014] [Accepted: 03/11/2014] [Indexed: 11/21/2022] Open
Abstract
Acetylcholine is a neuromodulatory transmitter that controls synaptic plasticity and sensory processing in many brain regions. The dorsal cochlear nucleus (DCN) is an auditory brainstem nucleus that integrates auditory signals from the cochlea with multisensory inputs from several brainstem nuclei and receives prominent cholinergic projections. In the auditory periphery, cholinergic modulation serves a neuroprotective function, reducing cochlear output under high sound levels. However, the role of cholinergic signaling in the DCN is less understood. Here we examine postsynaptic mechanisms of cholinergic modulation at glutamatergic synapses formed by parallel fiber axons onto cartwheel cells (CWCs) in the apical DCN circuit from mouse brainstem slice using calcium (Ca) imaging combined with two-photon laser glutamate uncaging onto CWC spines. Activation of muscarinic acetylcholine receptors (mAChRs) significantly increased the amplitude of both uncaging-evoked EPSPs (uEPSPs) and spine Ca transients. Our results demonstrate that mAChRs in CWC spines act by suppressing large-conductance calcium-activated potassium (BK) channels, and this effect is mediated through the cAMP/protein kinase A signaling pathway. Blocking BK channels relieves voltage-dependent magnesium block of NMDA receptors, thereby enhancing uEPSPs and spine Ca transients. Finally, we demonstrate that mAChR activation inhibits L-type Ca channels and thus may contribute to the suppression of BK channels by mAChRs. In summary, we demonstrate a novel role for BK channels in regulating glutamatergic transmission and show that this mechanism is under modulatory control of mAChRs.
Collapse
Affiliation(s)
- Shan He
- Section on Synaptic Transmission and
| | - Ya-Xian Wang
- Advanced Imaging Core, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, Maryland 20892
| | - Ronald S. Petralia
- Advanced Imaging Core, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, Maryland 20892
| | | |
Collapse
|
14
|
Ruat M, Faure H, Daynac M. Smoothened, Stem Cell Maintenance and Brain Diseases. TOPICS IN MEDICINAL CHEMISTRY 2014. [DOI: 10.1007/7355_2014_83] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
|
15
|
Mitchell N, Petralia RS, Currier DG, Wang YX, Kim A, Mattson MP, Yao PJ. Sonic hedgehog regulates presynaptic terminal size, ultrastructure and function in hippocampal neurons. J Cell Sci 2012; 125:4207-13. [PMID: 22641692 DOI: 10.1242/jcs.105080] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Sonic hedgehog (Shh) signaling is essential to the patterning of the embryonic neural tube, but its presence and function in the postmitotic differentiated neurons in the brain remain largely uncharacterized. We recently showed that Shh and its signaling components, Patched and Smoothened, are expressed in postnatal and adult hippocampal neurons. We have now examined whether Shh signaling has a function in these neurons. Using cultured hippocampal neurons as a model system, we found that presynaptic terminals become significantly larger in response to the application of Shh. Ultrastructural examination confirmed the enlarged presynaptic profiles and also revealed variable increases in the size of synaptic vesicles, with a resulting loss of uniformity. Furthermore, electrophysiological analyses showed significant increases in the frequency, but not the amplitude, of spontaneous miniature excitatory postsynaptic currents (mEPSCs) in response to Shh, providing functional evidence of the selective role of Shh in presynaptic terminals. Thus, we conclude that Shh signaling regulates the structure and functional properties of presynaptic terminals of hippocampal neurons.
Collapse
Affiliation(s)
- Nicholas Mitchell
- Laboratory of Neurosciences, National Institute on Aging Intramural Research Program, Baltimore, MD 21224, USA
| | | | | | | | | | | | | |
Collapse
|