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Li LT, Liu J, Luo M, Liu JS, Zhang MM, Zhang WJ, Chen HC, Liu ZF. Establishment of pseudorabies virus latency and reactivation model in mice dorsal root ganglia culture. J Gen Virol 2023; 104. [PMID: 37991423 DOI: 10.1099/jgv.0.001921] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2023] Open
Abstract
Pseudorabies virus (PRV) belongs to the alpha herpesvirus family and is responsible for Aujeszky's disease in pigs. Similar to other alpha herpesviruses, PRV establishes a lifelong latent infection in trigeminal ganglion. These latently infected pigs serve as a reservoir for recurrent infections when reactivation is triggered, making the eradication of PRV a challenging task. However, the molecular mechanism underlying PRV latency and reactivation in neurons is still poorly understood due to limitations in the in vitro model. To establish a pseudorabies virus latency and reactivation model in primary neuron cultures, we isolated dorsal root ganglion (DRG) from newborn Kunming mice using a method named epineurium-pulling for DRG collection (EPDC) and cultured primary neurons in vitro. A dual-colour recombinant PRV BAC mRuby-VP16 was constructed and 0.5 multiplicity of infection (MOI) was found as an appropriate dose in the presence of aciclovir to establish latency. Reactivation was induced using UV-inactivated herpesviruses or a series of chemical inhibitors. Interestingly, we found that not only UV-PRV, but also UV-HSV-1 and UV-BHoV-5 were able to induce rapid PRV reactivation. The efficiency of reactivation for LY294002, forskolin, etoposide, dexamethasone, and acetylcholine was found to be dependent on their concentration. In conclusion, we developed a valuable model of PRV latency and reactivation, which provides a basis for future mechanism research.
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Affiliation(s)
- Lin-Tao Li
- State Key Laboratory of Agricultural Microbiology and Hongshan Laboratory, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, PR China
| | - Jie Liu
- State Key Laboratory of Agricultural Microbiology and Hongshan Laboratory, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, PR China
| | - Miao Luo
- State Key Laboratory of Agricultural Microbiology and Hongshan Laboratory, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, PR China
| | - Jing-Song Liu
- State Key Laboratory of Agricultural Microbiology and Hongshan Laboratory, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, PR China
| | - Mei-Mei Zhang
- State Key Laboratory of Agricultural Microbiology and Hongshan Laboratory, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, PR China
| | - Wen-Jing Zhang
- State Key Laboratory of Agricultural Microbiology and Hongshan Laboratory, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, PR China
| | - Huan-Chun Chen
- State Key Laboratory of Agricultural Microbiology and Hongshan Laboratory, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, PR China
| | - Zheng-Fei Liu
- State Key Laboratory of Agricultural Microbiology and Hongshan Laboratory, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, PR China
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ENT-A010, a Novel Steroid Derivative, Displays Neuroprotective Functions and Modulates Microglial Responses. Biomolecules 2022; 12:biom12030424. [PMID: 35327616 PMCID: PMC8946810 DOI: 10.3390/biom12030424] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Revised: 03/02/2022] [Accepted: 03/05/2022] [Indexed: 11/17/2022] Open
Abstract
Tackling neurodegeneration and neuroinflammation is particularly challenging due to the complexity of central nervous system (CNS) disorders, as well as the limited drug accessibility to the brain. The activation of tropomyosin-related kinase A (TRKA) receptor signaling by the nerve growth factor (NGF) or the neurosteroid dehydroepiandrosterone (DHEA) may combat neurodegeneration and regulate microglial function. In the present study, we synthesized a C-17-spiro-cyclopropyl DHEA derivative (ENT-A010), which was capable of activating TRKA. ENT-A010 protected PC12 cells against serum starvation-induced cell death, dorsal root ganglia (DRG) neurons against NGF deprivation-induced apoptosis and hippocampal neurons against Aβ-induced apoptosis. In addition, ENT-A010 pretreatment partially restored homeostatic features of microglia in the hippocampus of lipopolysaccharide (LPS)-treated mice, enhanced Aβ phagocytosis, and increased Ngf expression in microglia in vitro. In conclusion, the small molecule ENT-A010 elicited neuroprotective effects and modulated microglial function, thereby emerging as an interesting compound, which merits further study in the treatment of CNS disorders.
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Development and Biological Characterization of a Novel Selective TrkA Agonist with Neuroprotective Properties against Amyloid Toxicity. Biomedicines 2022; 10:biomedicines10030614. [PMID: 35327415 PMCID: PMC8945229 DOI: 10.3390/biomedicines10030614] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Revised: 02/23/2022] [Accepted: 03/03/2022] [Indexed: 12/12/2022] Open
Abstract
Neurotrophins are growth factors that exert important neuroprotective effects by preventing neuronal death and synaptic loss. Nerve Growth Factor (NGF) acts through the activation of its high-affinity, pro-survival TrkA and low-affinity, pro-apoptotic p75NTR receptors. NGF has been shown to slow or prevent neurodegenerative signals in Alzheimer’s Disease (AD) progression. However, its low bioavailability and its blood–brain-barrier impermeability limit the use of NGF as a potential therapeutic agent against AD. Based on our previous findings on synthetic dehydroepiandrosterone derivatives, we identified a novel NGF mimetic, named ENT-A013, which selectively activates TrkA and exerts neuroprotective, anti-amyloid-β actions. We now report the chemical synthesis, in silico modelling, metabolic stability, CYP-mediated reaction phenotyping and biological characterization of ENT-A013 under physiological and neurodegenerative conditions. We show that ENT-A013 selectively activates the TrkA receptor and its downstream kinases Akt and Erk1/2 in PC12 cells, protecting these cells from serum deprivation-induced cell death. Moreover, ENT-A013 promotes survival of primary Dorsal Root Ganglion (DRG) neurons upon NGF withdrawal and protects hippocampal neurons against Amyloid β-induced apoptosis and synaptic loss. Furthermore, this neurotrophin mimetic partially restores LTP impairment. In conclusion, ENT-A013 represents a promising new lead molecule for developing therapeutics against neurodegenerative disorders, such as Alzheimer’s Disease, selectively targeting TrkA-mediated pro-survival signals.
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Ferron L, Novazzi CG, Pilch KS, Moreno C, Ramgoolam K, Dolphin AC. FMRP regulates presynaptic localization of neuronal voltage gated calcium channels. Neurobiol Dis 2020; 138:104779. [PMID: 31991246 PMCID: PMC7152798 DOI: 10.1016/j.nbd.2020.104779] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 01/09/2020] [Accepted: 01/24/2020] [Indexed: 12/31/2022] Open
Abstract
Fragile X syndrome (FXS), the most common form of inherited intellectual disability and autism, results from the loss of fragile X mental retardation protein (FMRP). We have recently identified a direct interaction of FMRP with voltage-gated Ca2+ channels that modulates neurotransmitter release. In the present study we used a combination of optophysiological tools to investigate the impact of FMRP on the targeting of voltage-gated Ca2+ channels to the active zones in neuronal presynaptic terminals. We monitored Ca2+ transients at synaptic boutons of dorsal root ganglion (DRG) neurons using the genetically-encoded Ca2+ indicator GCaMP6f tagged to synaptophysin. We show that knock-down of FMRP induces an increase of the amplitude of the Ca2+ transient in functionally-releasing presynaptic terminals, and that this effect is due to an increase of N-type Ca2+ channel contribution to the total Ca2+ transient. Dynamic regulation of CaV2.2 channel trafficking is key to the function of these channels in neurons. Using a CaV2.2 construct with an α-bungarotoxin binding site tag, we further investigate the impact of FMRP on the trafficking of CaV2.2 channels. We show that forward trafficking of CaV2.2 channels from the endoplasmic reticulum to the plasma membrane is reduced when co-expressed with FMRP. Altogether our data reveal a critical role of FMRP on localization of CaV channels to the presynaptic terminals and how its defect in a context of FXS can profoundly affect synaptic transmission. Loss of FMRP increases presynaptic Ca2+ transients. FMRP is a negative regulator of presynaptic Cav2.2 channel abundance. FMRP reduces the forward trafficking of Cav2.2 channels from ER to plasma membrane. Distal part of FMRP carboxy terminus is key for interaction with Cav2.2 channels.
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Affiliation(s)
- Laurent Ferron
- Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, UK.
| | - Cesare G Novazzi
- Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, UK
| | - Kjara S Pilch
- Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, UK
| | - Cristian Moreno
- Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, UK
| | - Krishma Ramgoolam
- Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, UK
| | - Annette C Dolphin
- Department of Neuroscience, Physiology and Pharmacology, University College London, London WC1E 6BT, UK
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Morgenstern TJ, Park J, Fan QR, Colecraft HM. A potent voltage-gated calcium channel inhibitor engineered from a nanobody targeted to auxiliary Ca Vβ subunits. eLife 2019; 8:49253. [PMID: 31403402 PMCID: PMC6701945 DOI: 10.7554/elife.49253] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Accepted: 08/10/2019] [Indexed: 12/15/2022] Open
Abstract
Inhibiting high-voltage-activated calcium channels (HVACCs; CaV1/CaV2) is therapeutic for myriad cardiovascular and neurological diseases. For particular applications, genetically-encoded HVACC blockers may enable channel inhibition with greater tissue-specificity and versatility than is achievable with small molecules. Here, we engineered a genetically-encoded HVACC inhibitor by first isolating an immunized llama nanobody (nb.F3) that binds auxiliary HVACC CaVβ subunits. Nb.F3 by itself is functionally inert, providing a convenient vehicle to target active moieties to CaVβ-associated channels. Nb.F3 fused to the catalytic HECT domain of Nedd4L (CaV-aβlator), an E3 ubiquitin ligase, ablated currents from diverse HVACCs reconstituted in HEK293 cells, and from endogenous CaV1/CaV2 channels in mammalian cardiomyocytes, dorsal root ganglion neurons, and pancreatic β cells. In cardiomyocytes, CaV-aβlator redistributed CaV1.2 channels from dyads to Rab-7-positive late endosomes. This work introduces CaV-aβlator as a potent genetically-encoded HVACC inhibitor, and describes a general approach that can be broadly adapted to generate versatile modulators for macro-molecular membrane protein complexes.
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Affiliation(s)
- Travis J Morgenstern
- Department of Pharmacology, Columbia University, Vagelos College of Physicians and Surgeons, New York, United States
| | - Jinseo Park
- Department of Pharmacology, Columbia University, Vagelos College of Physicians and Surgeons, New York, United States
| | - Qing R Fan
- Department of Pharmacology, Columbia University, Vagelos College of Physicians and Surgeons, New York, United States
| | - Henry M Colecraft
- Department of Pharmacology, Columbia University, Vagelos College of Physicians and Surgeons, New York, United States.,Department of Physiology and Cellular Biophysics, Columbia University, Vagelos College of Physicians and Surgeons, New York, United States
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Engineering selectivity into RGK GTPase inhibition of voltage-dependent calcium channels. Proc Natl Acad Sci U S A 2018; 115:12051-12056. [PMID: 30397133 PMCID: PMC6255209 DOI: 10.1073/pnas.1811024115] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Genetically encoded inhibitors for voltage-dependent Ca2+ (CaV) channels (GECCIs) are useful research tools and potential therapeutics. Rad/Rem/Rem2/Gem (RGK) proteins are Ras-like G proteins that potently inhibit high voltage-activated (HVA) Ca2+ (CaV1/CaV2 family) channels, but their nonselectivity limits their potential applications. We hypothesized that nonselectivity of RGK inhibition derives from their binding to auxiliary CaVβ-subunits. To investigate latent CaVβ-independent components of inhibition, we coexpressed each RGK individually with CaV1 (CaV1.2/CaV1.3) or CaV2 (CaV2.1/CaV2.2) channels reconstituted in HEK293 cells with either wild-type (WT) β2a or a mutant version (β2a,TM) that does not bind RGKs. All four RGKs strongly inhibited CaV1/CaV2 channels reconstituted with WT β2a By contrast, when channels were reconstituted with β2a,TM, Rem inhibited only CaV1.2, Rad selectively inhibited CaV1.2 and CaV2.2, while Gem and Rem2 were ineffective. We generated mutant RGKs (Rem[R200A/L227A] and Rad[R208A/L235A]) unable to bind WT CaVβ, as confirmed by fluorescence resonance energy transfer. Rem[R200A/L227A] selectively blocked reconstituted CaV1.2 while Rad[R208A/L235A] inhibited CaV1.2/CaV2.2 but not CaV1.3/CaV2.1. Rem[R200A/L227A] and Rad[R208A/L235A] both suppressed endogenous CaV1.2 channels in ventricular cardiomyocytes and selectively blocked 25 and 62%, respectively, of HVA currents in somatosensory neurons of the dorsal root ganglion, corresponding to their distinctive selectivity for CaV1.2 and CaV1.2/CaV2.2 channels. Thus, we have exploited latent β-binding-independent Rem and Rad inhibition of specific CaV1/CaV2 channels to develop selective GECCIs with properties unmatched by current small-molecule CaV channel blockers.
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Park JF, Yu YP, Gong N, Trinh VN, Luo ZD. The EGF-LIKE domain of thrombospondin-4 is a key determinant in the development of pain states due to increased excitatory synaptogenesis. J Biol Chem 2018; 293:16453-16463. [PMID: 30194282 DOI: 10.1074/jbc.ra118.003591] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2018] [Revised: 09/05/2018] [Indexed: 02/04/2023] Open
Abstract
Up-regulation of thrombospondin-4 (TSP4) or voltage-gated calcium channel subunit α2δ1 (Cavα2δ1) proteins in the spinal cord contributes to neuropathic pain development through an unidentified mechanism. We have previously shown that TSP4 interacts with Cavα2δ1 to promote excitatory synaptogenesis and the development of chronic pain states. However, the TSP4 determinants responsible for these changes are not known. Here, we tested the hypothesis that the Cavα2δ1-binding domains of TSP4 are synaptogenic and pronociceptive. We mapped the major Cavα2δ1-binding domains of TSP4 within the coiled-coil and epidermal growth factor (EGF)-like domains in vitro Intrathecal injection of TSP4 fragment proteins containing the EGF-like domain (EGF-LIKE) into naïve rodents was sufficient for inducing behavioral hypersensitivity similar to that produced by an equal molar dose of full-length TSP4. Gabapentin, a drug that binds to Cavα2δ1, blocked EGF-LIKE-induced behavioral hypersensitivity in a dose-dependent manner, supporting the notion that EGF-LIKE interacts with Cavα2δ1 and thereby mediates behavioral hypersensitivity. This notion was further supported by our findings that a peptide within EGF-LIKE (EGFD355-369) could block TSP4- or Cavα2δ1-induced behavioral hypersensitivity after intrathecal injections. Furthermore, only TSP4 proteins that contained EGF-LIKE could promote excitatory synaptogenesis between sensory and spinal cord neurons, which could be blocked by peptide EGFD355-369. Together, these findings indicate that EGF-LIKE is the molecular determinant that mediates aberrant excitatory synaptogenesis and chronic pain development. Blocking interactions between EGF-LIKE and Cavα2δ1 could be an alternative approach in designing target-specific pain medications.
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Affiliation(s)
| | | | - Nian Gong
- Anesthesiology and Perioperative Care, University of California, Irvine, California 92697
| | - Van Nancy Trinh
- Anesthesiology and Perioperative Care, University of California, Irvine, California 92697
| | - Z David Luo
- From the Departments of Pharmacology and .,Anesthesiology and Perioperative Care, University of California, Irvine, California 92697
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Yu YP, Gong N, Kweon TD, Vo B, Luo ZD. Gabapentin prevents synaptogenesis between sensory and spinal cord neurons induced by thrombospondin-4 acting on pre-synaptic Ca v α 2 δ 1 subunits and involving T-type Ca 2+ channels. Br J Pharmacol 2018; 175:2348-2361. [PMID: 29338087 PMCID: PMC5980510 DOI: 10.1111/bph.14149] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Revised: 12/22/2017] [Accepted: 01/08/2018] [Indexed: 01/12/2023] Open
Abstract
BACKGROUND AND PURPOSE Nerve injury induces concurrent up-regulation of the voltage-gated calcium channel subunit Cav α2 δ1 and the extracellular matrix protein thrombospondin-4 (TSP4) in dorsal root ganglia and dorsal spinal cord, leading to the development of a neuropathic pain state. Interactions of these proteins promote aberrant excitatory synaptogenesis that contributes to neuropathic pain state development through unknown mechanisms. We investigated the contributions of Cav α2 δ1 subunits and TSP4 to synaptogenesis, and the pathways involved in vitro, and whether treatment with gabapentin could block this process and pain development in vivo. EXPERIMENTAL APPROACH A co-culture system of sensory and spinal cord neurons was used to study the contribution from each protein to synaptogenesis and the pathway(s) involved. Anti-synaptogenic actions of gabapentin were studied in TSP4-injected mice. KEY RESULTS Only presynaptic, but not postsynaptic, Cav α2 δ1 subunits interacted with TSP4 to initiate excitatory synaptogenesis through a pathway modulated by T-type calcium channels. Cav α2 δ1 /TSP4 interactions were not required for maintenance of already formed synapses. In vivo, early, but not delayed, treatment with low-dose gabapentin blocked this pathway and the development of the pain state. CONCLUSIONS AND IMPLICATIONS Cav α2 δ1 /TSP4 interactions were critical for the initiation, but not for the maintenance, of abnormal synapse formation between sensory and spinal cord neurons. This process was blocked by early, but was not reversed by delayed, treatment with gabapentin. Early intervention with gabapentin may prevent the development of injury-induced chronic pain, resulting from Cav α2 δ1 /TSP4-initiated abnormal synapse formation. LINKED ARTICLES This article is part of a themed section on Recent Advances in Targeting Ion Channels to Treat Chronic Pain. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v175.12/issuetoc.
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Affiliation(s)
- Yanhui Peter Yu
- Department of PharmacologyUniversity of California, Irvine School of MedicineIrvineCAUSA
| | - Nian Gong
- Department of Anesthesiology & Perioperative CareUniversity of California, Irvine School of MedicineIrvineCAUSA
| | - Tae Dong Kweon
- Department of Anesthesiology & Perioperative CareUniversity of California, Irvine School of MedicineIrvineCAUSA
| | - Benjamin Vo
- Department of Anesthesiology & Perioperative CareUniversity of California, Irvine School of MedicineIrvineCAUSA
| | - Z David Luo
- Department of PharmacologyUniversity of California, Irvine School of MedicineIrvineCAUSA
- Department of Anesthesiology & Perioperative CareUniversity of California, Irvine School of MedicineIrvineCAUSA
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Sleigh JN, Weir GA, Schiavo G. A simple, step-by-step dissection protocol for the rapid isolation of mouse dorsal root ganglia. BMC Res Notes 2016; 9:82. [PMID: 26864470 PMCID: PMC4750296 DOI: 10.1186/s13104-016-1915-8] [Citation(s) in RCA: 90] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Accepted: 02/03/2016] [Indexed: 11/25/2022] Open
Abstract
Background The cell bodies of sensory neurons, which transmit information from the external environment to the spinal cord, can be found at all levels of the spinal column in paired structures called dorsal root ganglia (DRG). Rodent DRG neurons have long been studied in the laboratory to improve understanding of sensory nerve development and function, and have been instrumental in determining mechanisms underlying pain and neurodegeneration in disorders of the peripheral nervous system. Here, we describe a simple, step-by-step protocol for the swift isolation of mouse DRG, which can be enzymatically dissociated to produce fully differentiated primary neuronal cultures, or processed for downstream analyses, such as immunohistochemistry or RNA profiling. Findings After dissecting out the spinal column, from the base of the skull to the level of the femurs, it can be cut down the mid-line and the spinal cord and meninges removed, before extracting the DRG and detaching unwanted axons. This protocol allows the easy and rapid isolation of DRG with minimal practice and dissection experience. The process is both faster and less technically challenging than extracting the ganglia from the in situ column after performing a dorsal laminectomy. Conclusions This approach reduces the time required to collect DRG, thereby improving efficiency, permitting less opportunity for tissue deterioration, and, ultimately, increasing the chances of generating healthy primary DRG cultures or high quality, reproducible experiments using DRG tissue.
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Affiliation(s)
- James N Sleigh
- Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, London, WC1 N 3BG, UK.
| | - Greg A Weir
- Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford, OX3 9DU, UK.
| | - Giampietro Schiavo
- Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, University College London, London, WC1 N 3BG, UK.
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Wang L, Meece K, Williams DJ, Lo KA, Zimmer M, Heinrich G, Martin Carli J, Leduc CA, Sun L, Zeltser LM, Freeby M, Goland R, Tsang SH, Wardlaw SL, Egli D, Leibel RL. Differentiation of hypothalamic-like neurons from human pluripotent stem cells. J Clin Invest 2015; 125:796-808. [PMID: 25555215 DOI: 10.1172/jci79220] [Citation(s) in RCA: 83] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Accepted: 11/20/2014] [Indexed: 12/29/2022] Open
Abstract
The hypothalamus is the central regulator of systemic energy homeostasis, and its dysfunction can result in extreme body weight alterations. Insights into the complex cellular physiology of this region are critical to the understanding of obesity pathogenesis; however, human hypothalamic cells are largely inaccessible for direct study. Here, we developed a protocol for efficient generation of hypothalamic neurons from human embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs) obtained from patients with monogenetic forms of obesity. Combined early activation of sonic hedgehog signaling followed by timed NOTCH inhibition in human ESCs/iPSCs resulted in efficient conversion into hypothalamic NKX2.1+ precursors. Application of a NOTCH inhibitor and brain-derived neurotrophic factor (BDNF) further directed the cells into arcuate nucleus hypothalamic-like neurons that express hypothalamic neuron markers proopiomelanocortin (POMC), neuropeptide Y (NPY), agouti-related peptide (AGRP), somatostatin, and dopamine. These hypothalamic-like neurons accounted for over 90% of differentiated cells and exhibited transcriptional profiles defined by a hypothalamic-specific gene expression signature that lacked pituitary markers. Importantly, these cells displayed hypothalamic neuron characteristics, including production and secretion of neuropeptides and increased p-AKT and p-STAT3 in response to insulin and leptin. Our results suggest that these hypothalamic-like neurons have potential for further investigation of the neurophysiology of body weight regulation and evaluation of therapeutic targets for obesity.
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Unsain N, Heard KN, Higgins JM, Barker PA. Production and isolation of axons from sensory neurons for biochemical analysis using porous filters. J Vis Exp 2014:51795. [PMID: 25046441 PMCID: PMC4212973 DOI: 10.3791/51795] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Neuronal axons use specific mechanisms to mediate extension, maintain integrity, and induce degeneration. An appropriate balance of these events is required to shape functional neuronal circuits. The protocol described here explains how to use cell culture inserts bearing a porous membrane (filter) to obtain large amounts of pure axonal preparations suitable for examination by conventional biochemical or immunocytochemical techniques. The functionality of these filter inserts will be demonstrated with models of developmental pruning and Wallerian degeneration, using explants of embryonic dorsal root ganglion. Axonal integrity and function is compromised in a wide variety of neurodegenerative pathologies. Indeed, it is now clear that axonal dysfunction appears much earlier in the course of the disease than neuronal soma loss in several neurodegenerative diseases, indicating that axonal-specific processes are primarily targeted in these disorders. By obtaining pure axonal samples for analysis by molecular and biochemical techniques, this technique has the potential to shed new light into mechanisms regulating the physiology and pathophysiology of axons. This in turn will have an impact in our understanding of the processes that drive degenerative diseases of the nervous system.
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Affiliation(s)
- Nicolas Unsain
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University
| | - Kristen N Heard
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University
| | - Julia M Higgins
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University
| | - Philip A Barker
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University;
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Kaplan A, Sanz R, Ferraro GB, Alchini R, Fournier AE. Neurite outgrowth and growth cone collapse assays to assess neuronal responses to extracellular cues. Methods Mol Biol 2014; 1162:43-56. [PMID: 24838957 DOI: 10.1007/978-1-4939-0777-9_4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The identification of molecular processes involved in regulating neurite outgrowth is an active area of interest for investigators studying neural development and regeneration. In vitro assays designed to measure growth cone morphology and neurite length are frequently used to assess neuronal responses to developmental guidance cues and inhibitory cues that exist in the adult CNS. Here, we describe the procedures to assess morphological responses of cultured dorsal root ganglion neurons to attractive and repellent cues, with a focus on repellents found in the injured adult CNS. The chapter describes methods to culture the DRGs, apply inhibitory ligands, and assess morphological responses. These assays provide biological readouts to assess the capacity of a molecule to act as an inhibitory or growth promoting cue. The readouts can be used as screening tools to aid in the identification of novel targets or drugs for promoting nerve regeneration.
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Affiliation(s)
- Andrew Kaplan
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, BT-109, 3801 Rue University, Montreal, QC, Canada, H3A 2B4
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13
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Joseph DJ, Williams DJ, MacDermott AB. Modulation of neurite outgrowth by activation of calcium-permeable kainate receptors expressed by rat nociceptive-like dorsal root ganglion neurons. Dev Neurobiol 2011; 71:818-35. [PMID: 21557511 PMCID: PMC3973019 DOI: 10.1002/dneu.20906] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Neurite outgrowth is a fundamental step in establishing proper neuronal connections in the developing central nervous system. Dynamic control of outgrowth has been attributed to changes in growth cone Ca2+ levels in response to extracellular cues. Here we have investigated a possible role for Ca2+ permeable kainate (KA) receptors in regulating neurite outgrowth of nociceptive-like dorsal root ganglion (DRG) neurons. To identify KA receptor subunits likely to be involved, we used quantitative RT-PCR on acutely dissociated DRG and dorsal horn neurons. DRG neurons expressed more GluK1, particularly the GluK1b spice variant, than dorsal horn neurons. Conversely, dorsal horn neurons expressed more GluK2, particularly GluK2a, than DRG neurons. Further, an RNA editing assay indicated that the majority of GluK1 and GluK2 mRNA transcripts in DRG were unedited. Imaging Ca2+ transients following application of a KA receptor agonist to DRG and dorsal horn co-cultures revealed increases in intracellular Ca2+ in the growth cones of DRG neurons. In the majority of cases, this increase in Ca2+ was partly or completely blocked by Joro spider toxin (JSTX), an antagonist for Ca2+-permeable AMPA and KA receptors. Treatment of DRG/dorsal horn co-cultures with KA for 18 hours suppressed neurite outgrowth while application of the rapidly desensitizing KA receptor agonist SYM 2081, the competitive AMPA/KA receptor antagonist, CNQX, and JSTX or philanthotoxin enhanced neurite outgrowth and prevented KA effects on neurite outgrowth. Thus, Ca2+ entry through KA receptors at the growth cone of DRG neurons may be an important regulator of neurite outgrowth.
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Affiliation(s)
- Donald J. Joseph
- Program in Neurobiology and Behavior-Department of Neuroscience, Columbia University, New York, NY 10032
| | - Damian J. Williams
- Department of Physiology and Biophysics, Columbia University, New York, NY 10032
| | - Amy B. MacDermott
- Program in Neurobiology and Behavior-Department of Neuroscience, Columbia University, New York, NY 10032
- Department of Physiology and Biophysics, Columbia University, New York, NY 10032
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Joseph DJ, Choudhury P, MacDermott AB. An in vitro assay system for studying synapse formation between nociceptive dorsal root ganglion and dorsal horn neurons. J Neurosci Methods 2010; 189:197-204. [PMID: 20385165 PMCID: PMC2880384 DOI: 10.1016/j.jneumeth.2010.04.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2010] [Revised: 03/25/2010] [Accepted: 04/05/2010] [Indexed: 01/23/2023]
Abstract
Synapses between nociceptive dorsal root ganglion (DRG) neurons and spinal cord dorsal horn neurons represent the first loci for transmission of painful stimuli. Our knowledge of the molecular organization and development of these synapses is sparse due, partly, to a lack of a reliable model system that reconstitutes synaptogenesis between these two neuronal populations. To address this issue, we have established an in vitro assay system consisting of separately purified DRG neurons and dorsal horn neurons on astrocyte microislands. Using immunocytochemistry, we have found that 97%, 93%, 98%, 96%, and 94% of DRG neurons on these microislands express markers often associated with nociceptive neurons including Substance P, TRPV1, calcitonin-gene related peptide (CGRP), TrKA, and peripherin, respectively. Triple labeling with these nociceptive-like markers, synaptic vesicle marker Vglut2 and using MAP2 as a dendritic marker revealed the presence of nociceptive-like markers at synaptic terminals. Using this immunocytochemical approach, we counted contact points as overlapping MAP2/Vglut2 puncta and showed that they increased with time in culture. Single and dual patch-clamp recordings showed that overlapping Vglut2/MAP2 puncta observed after a few days in culture are likely to be functional synapses between DRG and dorsal horn neurons in our in vitro assay system. Taken together, these data suggest our co-culture microisland model system consists of mostly nociceptive-like DRG neurons that express presynaptic markers and form functional synapses with their dorsal horn partners. Thus, this model system may have direct application for studies on factors regulating development of nociceptive DRG/dorsal horn synapses.
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Affiliation(s)
- Donald J. Joseph
- Program in Neurobiology and Behavior-Department of Neuroscience, College of Physicians and Surgeons, Columbia University, New York, NY 10032
| | - Papiya Choudhury
- Department of Physiology and Biophysics, College of Physicians and Surgeons, Columbia University, New York, NY 10032
| | - Amy B. MacDermott
- Program in Neurobiology and Behavior-Department of Neuroscience, College of Physicians and Surgeons, Columbia University, New York, NY 10032
- Department of Physiology and Biophysics, College of Physicians and Surgeons, Columbia University, New York, NY 10032
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15
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Albuquerque C, Joseph DJ, Choudhury P, MacDermott AB. Dissection, plating, and maintenance of dorsal horn neuron cultures. Cold Spring Harb Protoc 2010; 2009:pdb.prot5274. [PMID: 20147250 DOI: 10.1101/pdb.prot5274] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Affiliation(s)
- Cristóvão Albuquerque
- Department of Physiology and Cellular Biophysics and Department of Neuroscience, Columbia University, New York, NY 10032, USA
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16
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Albuquerque C, Joseph DJ, Choudhury P, MacDermott AB. Preparation of coverslips for neuronal cultures. Cold Spring Harb Protoc 2010; 2009:pdb.prot5272. [PMID: 20147248 DOI: 10.1101/pdb.prot5272] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Affiliation(s)
- Cristóvão Albuquerque
- Department of Physiology and Cellular Biophysics and Department of Neuroscience, Columbia University, New York, NY 10032, USA
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17
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Albuquerque C, Joseph DJ, Choudhury P, MacDermott AB. Dissection, plating, and maintenance of cortical astrocyte cultures. Cold Spring Harb Protoc 2010; 2009:pdb.prot5273. [PMID: 20147249 DOI: 10.1101/pdb.prot5273] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Affiliation(s)
- Cristóvão Albuquerque
- Department of Physiology and Cellular Biophysics and Department of Neuroscience, Columbia University, New York, NY 10032, USA
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