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Hackney CM, Flórez Salcedo P, Mueller E, Koch TL, Kjelgaard LD, Watkins M, Zachariassen LG, Tuelung PS, McArthur JR, Adams DJ, Kristensen AS, Olivera B, Finol-Urdaneta RK, Safavi-Hemami H, Morth JP, Ellgaard L. A previously unrecognized superfamily of macro-conotoxins includes an inhibitor of the sensory neuron calcium channel Cav2.3. PLoS Biol 2023; 21:e3002217. [PMID: 37535677 PMCID: PMC10437998 DOI: 10.1371/journal.pbio.3002217] [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: 01/17/2023] [Revised: 08/18/2023] [Accepted: 06/27/2023] [Indexed: 08/05/2023] Open
Abstract
Animal venom peptides represent valuable compounds for biomedical exploration. The venoms of marine cone snails constitute a particularly rich source of peptide toxins, known as conotoxins. Here, we identify the sequence of an unusually large conotoxin, Mu8.1, which defines a new class of conotoxins evolutionarily related to the well-known con-ikot-ikots and 2 additional conotoxin classes not previously described. The crystal structure of recombinant Mu8.1 displays a saposin-like fold and shows structural similarity with con-ikot-ikot. Functional studies demonstrate that Mu8.1 curtails calcium influx in defined classes of murine somatosensory dorsal root ganglion (DRG) neurons. When tested on a variety of recombinantly expressed voltage-gated ion channels, Mu8.1 displayed the highest potency against the R-type (Cav2.3) calcium channel. Ca2+ signals from Mu8.1-sensitive DRG neurons were also inhibited by SNX-482, a known spider peptide modulator of Cav2.3 and voltage-gated K+ (Kv4) channels. Our findings highlight the potential of Mu8.1 as a molecular tool to identify and study neuronal subclasses expressing Cav2.3. Importantly, this multidisciplinary study showcases the potential of uncovering novel structures and bioactivities within the largely unexplored group of macro-conotoxins.
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Affiliation(s)
- Celeste M. Hackney
- Department of Biology, Linderstrøm-Lang Centre for Protein Science, University of Copenhagen, Copenhagen, Denmark
| | - Paula Flórez Salcedo
- Department of Neurobiology and Anatomy, University of Utah, Salt Lake City, Utah, United States of America
| | - Emilie Mueller
- Enzyme and Protein Chemistry, Section for Protein Chemistry and Enzyme Technology, Department of Biotechnology and Biomedicine, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Thomas Lund Koch
- Department of Biochemistry, University of Utah, Salt Lake City, Utah, United States of America
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Lau D. Kjelgaard
- Department of Biology, Linderstrøm-Lang Centre for Protein Science, University of Copenhagen, Copenhagen, Denmark
| | - Maren Watkins
- School of Biological Sciences, University of Utah, Salt Lake City, Utah, United States of America
| | - Linda G. Zachariassen
- Department of Drug Design & Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | | | - Jeffrey R. McArthur
- Illawarra Health and Medical Research Institute (IHMRI), Faculty of Science, Medicine and Health, University of Wollongong, Wollongong, Australia
| | - David J. Adams
- Illawarra Health and Medical Research Institute (IHMRI), Faculty of Science, Medicine and Health, University of Wollongong, Wollongong, Australia
| | - Anders S. Kristensen
- Department of Drug Design & Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Baldomero Olivera
- School of Biological Sciences, University of Utah, Salt Lake City, Utah, United States of America
| | - Rocio K. Finol-Urdaneta
- Illawarra Health and Medical Research Institute (IHMRI), Faculty of Science, Medicine and Health, University of Wollongong, Wollongong, Australia
- Electrophysiology Facility for Cell Phenotyping and Drug Discovery, Wollongong, Australia
| | - Helena Safavi-Hemami
- Department of Biochemistry, University of Utah, Salt Lake City, Utah, United States of America
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
- School of Biological Sciences, University of Utah, Salt Lake City, Utah, United States of America
| | - Jens Preben Morth
- Enzyme and Protein Chemistry, Section for Protein Chemistry and Enzyme Technology, Department of Biotechnology and Biomedicine, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Lars Ellgaard
- Department of Biology, Linderstrøm-Lang Centre for Protein Science, University of Copenhagen, Copenhagen, Denmark
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2
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Oz M, Lorke DE, Howarth FC. Transient receptor potential vanilloid 1 (TRPV1)-independent actions of capsaicin on cellular excitability and ion transport. Med Res Rev 2023. [PMID: 36916676 DOI: 10.1002/med.21945] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Revised: 01/17/2023] [Accepted: 02/26/2023] [Indexed: 03/15/2023]
Abstract
Capsaicin is a naturally occurring alkaloid derived from chili pepper that is responsible for its hot pungent taste. Capsaicin is known to exert multiple pharmacological actions, including analgesia, anticancer, anti-inflammatory, antiobesity, and antioxidant effects. The transient receptor potential vanilloid subfamily member 1 (TRPV1) is the main receptor mediating the majority of the capsaicin effects. However, numerous studies suggest that the TRPV1 receptor is not the only target for capsaicin. An increasing number of studies indicates that capsaicin, at low to mid µM ranges, not only indirectly through TRPV1-mediated Ca2+ increases, but also directly modulates the functions of voltage-gated Na+ , K+ , and Ca2+ channels, as well as ligand-gated ion channels and other ion transporters and enzymes involved in cellular excitability. These TRPV1-independent effects are mediated by alterations of the biophysical properties of the lipid membrane and subsequent modulation of the functional properties of ion channels and by direct binding of capsaicin to the channels. The present study, for the first time, systematically categorizes this diverse range of non-TRPV1 targets and discusses cellular and molecular mechanisms mediating TRPV1-independent effects of capsaicin in excitable, as well as nonexcitable cells.
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Affiliation(s)
- Murat Oz
- Department of Pharmacology and Therapeutics, Faculty of Pharmacy, Kuwait University, Safat, Kuwait
| | - Dietrich E Lorke
- Department of Anatomy and Cellular Biology, College of Medicine and Health Sciences, Khalifa University, Abu Dhabi, United Arab Emirates.,Center for Biotechnology, Khalifa University of Science and Technology, Abu Dhabi, United Arab Emirates
| | - Frank C Howarth
- Department of Physiology, College of Medicine and Health Sciences, UAE University, Al Ain, United Arab Emirates
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3
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Jiang Y, Feng C, Shi Y, Kou X, Le G. Eugenol improves high-fat diet/streptomycin-induced type 2 diabetes mellitus (T2DM) mice muscle dysfunction by alleviating inflammation and increasing muscle glucose uptake. Front Nutr 2022; 9:1039753. [PMID: 36424928 PMCID: PMC9681568 DOI: 10.3389/fnut.2022.1039753] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Accepted: 10/03/2022] [Indexed: 08/10/2023] Open
Abstract
Eugenol has been used in dietary interventions for metabolic diseases such as diabetes and obesity. However, the protective effect of eugenol on muscle function in diabetes is unclear. In this study, a high-fat diet (HFD) with a streptozocin (STZ) injection induced type II diabetes mellitus in a mouse model. Oral eugenol lowered blood glucose and insulin resistance of HFD/STZ-treated mice. Eugenol reduced HFD/STZ-induced muscle inflammation and prevented muscle weakness and atrophy. Eugenol administration significantly increased GLUT4 translocation and AMPK phosphorylation in skeletal muscle, thereby enhancing glucose uptake. By silencing the transient receptor potential vanilloid channel 1 (TRPV1) gene in C2C12 myotube cells, eugenol was found to increase intracellular Ca2+ levels through TRPV1, which then activated calmodulin-dependent protein kinase-2 (CaMKK2) and affected AMPK protein phosphorylation. In conclusion, eugenol is a potential nutraceutical for preventing high-glucose-induced muscle impairments, which could be explained by its mediating effects on glucose absorption and inflammatory responses in the muscle.
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Affiliation(s)
- Yuge Jiang
- Center for Food Nutrition and Functional Food Engineering, School of Food Science and Technology, Jiangnan University, Wuxi, China
- The State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, China
| | - Chuanxing Feng
- Center for Food Nutrition and Functional Food Engineering, School of Food Science and Technology, Jiangnan University, Wuxi, China
- The State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, China
| | - Yonghui Shi
- Center for Food Nutrition and Functional Food Engineering, School of Food Science and Technology, Jiangnan University, Wuxi, China
- The State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, China
| | - Xingran Kou
- School of Perfume and Aroma Technology, Shanghai Institute of Technology, Shanghai, China
| | - Guowei Le
- Center for Food Nutrition and Functional Food Engineering, School of Food Science and Technology, Jiangnan University, Wuxi, China
- The State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi, China
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4
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McArthur JR, Wen J, Hung A, Finol-Urdaneta RK, Adams DJ. µ-Theraphotoxin-Pn3a inhibition of Ca V3.3 channels reveals a novel isoform-selective drug binding site. eLife 2022; 11:74040. [PMID: 35858123 PMCID: PMC9342953 DOI: 10.7554/elife.74040] [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] [Received: 09/20/2021] [Accepted: 07/19/2022] [Indexed: 11/13/2022] Open
Abstract
Low voltage-activated calcium currents are mediated by T-type calcium channels CaV3.1, CaV3.2, and CaV3.3, which modulate a variety of physiological processes including sleep, cardiac pace-making, pain, and epilepsy. CaV3 isoforms’ biophysical properties, overlapping expression, and lack of subtype-selective pharmacology hinder the determination of their specific physiological roles in health and disease. We have identified μ-theraphotoxin Pn3a as the first subtype-selective spider venom peptide inhibitor of CaV3.3, with >100-fold lower potency against the other T-type isoforms. Pn3a modifies CaV3.3 gating through a depolarizing shift in the voltage dependence of activation thus decreasing CaV3.3-mediated currents in the normal range of activation potentials. Paddle chimeras of KV1.7 channels bearing voltage sensor sequences from all four CaV3.3 domains revealed preferential binding of Pn3a to the S3-S4 region of domain II (CaV3.3DII). This novel T-type channel pharmacological site was explored through computational docking simulations of Pn3a, site-directed mutagenesis, and full domain II swaps between CaV3 channels highlighting it as a subtype-specific pharmacophore. This research expands our understanding of T-type calcium channel pharmacology and supports the suitability of Pn3a as a molecular tool in the study of the physiological roles of CaV3.3 channels.
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Affiliation(s)
- Jeffrey R McArthur
- Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, Australia
| | - Jierong Wen
- School of Science, RMIT University, Melbourne, Australia
| | - Andrew Hung
- School of Science, RMIT University, Melbourne, Australia
| | - Rocio K Finol-Urdaneta
- Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, Australia
| | - David J Adams
- Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, Australia
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5
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Matsushita Y, Manabe M, Kitagawa I, Higuchi M, Hosaka YZ, Kitamura N. Inhibition of transient receptor potential vanilloid type 1 through α 2 adrenergic receptors at peripheral nerve terminals relieves pain. J Vet Med Sci 2021; 83:1570-1581. [PMID: 34470979 PMCID: PMC8569874 DOI: 10.1292/jvms.21-0429] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The activation of α2 adrenergic receptors contributes to analgesia not only in
the central nervous system but also in the peripheral nervous system. We reported that
noradrenaline inhibits the activity of transient receptor potential vanilloid 1 (TRPV1)
evoked by capsaicin through α2 receptors in cultured rat dorsal root ganglion
(DRG) neurons. However, it is unclear whether activation of TRPV1 expressed in peripheral
nerve terminals is inhibited by α2 receptors and whether this phenomenon
contributes to analgesia. Therefore, we examined effects of clonidine, an α2
receptor agonist, on several types of nociceptive behaviors, which may be caused by TRPV1
activity, and subtypes of α2 receptors expressed with TRPV1 in primary sensory
neurons in rats. Capsaicin injected into hind paws evoked nociceptive behaviors and
clonidine preinjected into the same site inhibited capsaicin-evoked responses. This
inhibition was not observed when clonidine was injected into the contralateral hind paws.
Preinjection of clonidine into the plantar surface of ipsilateral, but not contralateral,
hind paws reduced the sensitivity to heat stimuli. Clonidine partially reduced
formalin-evoked responses when it was preinjected into ipsilateral hind paws. The
expression level of α2C receptor mRNA quantified by real-time PCR was highest
followed by those of α2A and α2B receptors in DRGs. α2A
and α2C receptor-like immunoreactivities were detected with TRPV1-like
immunoreactivities in the same neurons. These results suggest that TRPV1 and α2
receptors are coexpressed in peripheral nerve terminals and that the functional
association between these two molecules causes analgesia.
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Affiliation(s)
- Yumi Matsushita
- The United Graduate School of Veterinary Science, Yamaguchi University, Yamaguchi 753-8511, Japan.,Laboratory of Veterinary Physiology, Faculty of Agriculture, Tottori University, Tottori 680-8553, Japan
| | - Miki Manabe
- Laboratory of Veterinary Physiology, Faculty of Agriculture, Tottori University, Tottori 680-8553, Japan
| | - Issei Kitagawa
- Laboratory of Veterinary Physiology, Faculty of Agriculture, Tottori University, Tottori 680-8553, Japan
| | - Masashi Higuchi
- The United Graduate School of Veterinary Science, Yamaguchi University, Yamaguchi 753-8511, Japan.,Laboratory of Veterinary Biochemistry, Faculty of Agriculture, Tottori University, Tottori 680-8553, Japan
| | - Yoshinao Z Hosaka
- The United Graduate School of Veterinary Science, Yamaguchi University, Yamaguchi 753-8511, Japan.,Laboratory of Veterinary Anatomy, Faculty of Agriculture, Tottori University, Tottori 680-8553, Japan
| | - Naoki Kitamura
- The United Graduate School of Veterinary Science, Yamaguchi University, Yamaguchi 753-8511, Japan.,Laboratory of Veterinary Physiology, Faculty of Agriculture, Tottori University, Tottori 680-8553, Japan
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6
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McArthur JR, Munasinghe NR, Finol-Urdaneta RK, Adams DJ, Christie MJ. Spider Venom Peptide Pn3a Inhibition of Primary Afferent High Voltage-Activated Calcium Channels. Front Pharmacol 2021; 11:633679. [PMID: 33584315 PMCID: PMC7875911 DOI: 10.3389/fphar.2020.633679] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Accepted: 12/30/2020] [Indexed: 11/19/2022] Open
Abstract
Despite potently inhibiting the nociceptive voltage-gated sodium (Nav) channel, Nav1.7, µ-theraphotoxin Pn3a is antinociceptive only upon co-administration with sub-therapeutic opioid agonists, or by itself at doses >3,000-fold greater than its Nav1.7 IC50 by a yet undefined mechanism. Nav channels are structurally related to voltage-gated calcium (Cav) channels, Cav1 and Cav2. These channels mediate the high voltage-activated (HVA) calcium currents (ICa) that orchestrate synaptic transmission in nociceptive dorsal root ganglion (DRG) neurons and are fine-tuned by opioid receptor (OR) activity. Using whole-cell patch clamp recording, we found that Pn3a (10 µM) inhibits ∼55% of rat DRG neuron HVA-ICa and 60–80% of Cav1.2, Cav1.3, Cav2.1, and Cav2.2 mediated currents in HEK293 cells, with no inhibition of Cav2.3. As a major DRG ICa component, Cav2.2 inhibition by Pn3a (IC50 = 3.71 ± 0.21 µM) arises from an 18 mV hyperpolarizing shift in the voltage dependence of inactivation. We observed that co-application of Pn3a and µ-OR agonist DAMGO results in enhanced HVA-ICa inhibition in DRG neurons whereas co-application of Pn3a with the OR antagonist naloxone does not, underscoring HVA channels as shared targets of Pn3a and opioids. We provide evidence that Pn3a inhibits native and recombinant HVA Cavs at previously reportedly antinociceptive concentrations in animal pain models. We show additive modulation of DRG HVA-ICa by sequential application of low Pn3a doses and sub-therapeutic opioids ligands. We propose Pn3a's antinociceptive effects result, at least in part, from direct inhibition of HVA-ICa at high Pn3a doses, or through additive inhibition by low Pn3a and mild OR activation.
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Affiliation(s)
- Jeffrey R McArthur
- Illawarra Health and Medical Research Institute (IHMRI), University of Wollongong, Wollongong, NSW, Australia
| | - Nehan R Munasinghe
- Discipline of Pharmacology, University of Sydney, Sydney, NSW, Australia
| | - Rocio K Finol-Urdaneta
- Illawarra Health and Medical Research Institute (IHMRI), University of Wollongong, Wollongong, NSW, Australia.,Electrophysiology Facility for Cell Phenotyping and Drug Discovery, IHMRI, Wollongong, NSW, Australia
| | - David J Adams
- Illawarra Health and Medical Research Institute (IHMRI), University of Wollongong, Wollongong, NSW, Australia
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7
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Basharat S, Gilani SA, Iftikhar F, Murtaza MA, Basharat A, Sattar A, Qamar MM, Ali M. Capsaicin: Plants of the Genus Capsicum and Positive Effect of Oriental Spice on Skin Health. Skin Pharmacol Physiol 2021; 33:331-341. [PMID: 33401283 DOI: 10.1159/000512196] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2019] [Accepted: 08/28/2020] [Indexed: 11/19/2022]
Abstract
BACKGROUND Capsaicin, the main pungent ingredient in hot chili peppers, causes excitation of small sensory neurons. It also provides the basic pungent flavor in Capsicum fruits. SUMMARY Capsaicin plays a vital role as an agonist for the TRPV1 (transient receptor potential cation channel, subfamily V, member 1) receptor. TRPV1 is essential for the reduction of oxidative stress, pain sensations, and inflammation. Therefore, it has many pros related to health issue. Activation and positive impact of TRPV1 via capsaicin has been studied in various dermatological conditions and in other skin-related issues. Past studies documented that capsaicin plays a vital role in the prevention of atopic dermatitis as well as psoriasis. Moreover, TRPV1 is also very important for skin health because it acts as a capsaicin receptor. It is found in nociceptive nerve fibers and nonneural structures. It prompts the release of a compound that is involved in communicating pain between the spinal cord nerves and other parts of the body. Key Messages: Here, we summarize the growing evidence for the beneficial role of capsaicin and TRPV1 and how they help in the relief of skin diseases such as inflammation, permeation, dysfunction, atopic dermatitis, and psoriasis and in pain amplification syndrome.
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Affiliation(s)
- Shahnai Basharat
- University Institute of Diet & Nutritional Sciences, The University of Lahore, Sargodha, Pakistan,
| | - Syed Amir Gilani
- Dean, Faculty of Allied Health Sciences, The University of Lahore, Lahore, Pakistan
| | - Faiza Iftikhar
- University Institute of Diet & Nutritional Sciences, The University of Lahore, Sargodha, Pakistan
| | | | - Ayesha Basharat
- Sargodha Medical College, University of Sargodha, Sargodha, Pakistan
| | - Ahsan Sattar
- Food Microbiology and Technology, Bahaudin Zikriya University, Multan, Pakistan
| | - Muhammad Mustafa Qamar
- Department of Physical Therapy, Sargodha Medical College, The University of Sargodha, Sargodha, Pakistan
| | - Muhammad Ali
- Institute of Allied Health Sciences, Sargodha Medical College, The University of Sargodha, Sargodha, Pakistan
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8
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Hulme AJ, McArthur JR, Maksour S, Miellet S, Ooi L, Adams DJ, Finol-Urdaneta RK, Dottori M. Molecular and Functional Characterization of Neurogenin-2 Induced Human Sensory Neurons. Front Cell Neurosci 2020; 14:600895. [PMID: 33362470 PMCID: PMC7761588 DOI: 10.3389/fncel.2020.600895] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 11/13/2020] [Indexed: 01/15/2023] Open
Abstract
Sensory perception is fundamental to everyday life, yet understanding of human sensory physiology at the molecular level is hindered due to constraints on tissue availability. Emerging strategies to study and characterize peripheral neuropathies in vitro involve the use of human pluripotent stem cells (hPSCs) differentiated into dorsal root ganglion (DRG) sensory neurons. However, neuronal functionality and maturity are limited and underexplored. A recent and promising approach for directing hPSC differentiation towards functionally mature neurons involves the exogenous expression of Neurogenin-2 (NGN2). The optimized protocol described here generates sensory neurons from hPSC-derived neural crest (NC) progenitors through virally induced NGN2 expression. NC cells were derived from hPSCs via a small molecule inhibitor approach and enriched for migrating NC cells (66% SOX10+ cells). At the protein and transcript level, the resulting NGN2 induced sensory neurons (NGN2iSNs) express sensory neuron markers such as BRN3A (82% BRN3A+ cells), ISLET1 (91% ISLET1+ cells), TRKA, TRKB, and TRKC. Importantly, NGN2iSNs repetitively fire action potentials (APs) supported by voltage-gated sodium, potassium, and calcium conductances. In-depth analysis of the molecular basis of NGN2iSN excitability revealed functional expression of ion channels associated with the excitability of primary afferent neurons, such as Nav1.7, Nav1.8, Kv1.2, Kv2.1, BK, Cav2.1, Cav2.2, Cav3.2, ASICs and HCN among other ion channels, for which we provide functional and transcriptional evidence. Our characterization of stem cell-derived sensory neurons sheds light on the molecular basis of human sensory physiology and highlights the suitability of using hPSC-derived sensory neurons for modeling human DRG development and their potential in the study of human peripheral neuropathies and drug therapies.
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Affiliation(s)
- Amy J Hulme
- Illawarra Health and Medical Research Institute, Wollongong, NSW, Australia.,School of Medicine, University of Wollongong, Wollongong, NSW, Australia
| | - Jeffrey R McArthur
- Illawarra Health and Medical Research Institute, Wollongong, NSW, Australia.,School of Medicine, University of Wollongong, Wollongong, NSW, Australia
| | - Simon Maksour
- Illawarra Health and Medical Research Institute, Wollongong, NSW, Australia.,School of Medicine, University of Wollongong, Wollongong, NSW, Australia
| | - Sara Miellet
- Illawarra Health and Medical Research Institute, Wollongong, NSW, Australia.,School of Medicine, University of Wollongong, Wollongong, NSW, Australia
| | - Lezanne Ooi
- Illawarra Health and Medical Research Institute, Wollongong, NSW, Australia.,School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW, Australia.,Molecular Horizons, University of Wollongong, Wollongong, NSW, Australia
| | - David J Adams
- Illawarra Health and Medical Research Institute, Wollongong, NSW, Australia.,School of Medicine, University of Wollongong, Wollongong, NSW, Australia.,Molecular Horizons, University of Wollongong, Wollongong, NSW, Australia
| | - Rocio K Finol-Urdaneta
- Illawarra Health and Medical Research Institute, Wollongong, NSW, Australia.,School of Medicine, University of Wollongong, Wollongong, NSW, Australia
| | - Mirella Dottori
- Illawarra Health and Medical Research Institute, Wollongong, NSW, Australia.,School of Medicine, University of Wollongong, Wollongong, NSW, Australia.,Molecular Horizons, University of Wollongong, Wollongong, NSW, Australia
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9
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McArthur JR, Finol-Urdaneta RK, Adams DJ. Analgesic transient receptor potential vanilloid-1-active compounds inhibit native and recombinant T-type calcium channels. Br J Pharmacol 2019; 176:2264-2278. [PMID: 30927254 DOI: 10.1111/bph.14676] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Revised: 03/07/2019] [Accepted: 03/21/2019] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND AND PURPOSE T-type calcium (Cav 3) and transient receptor potential vanilloid-1 (TRPV1) channels play central roles in the control of excitability in the peripheral nervous system and are regarded as potential therapeutic pain targets. Modulators that either activate or inhibit TRPV1-mediated currents display analgesic properties in various pain models despite opposing effects on their connate target, TRPV1. We explored the effects of TRPV1-active compounds on Cav 3-mediated currents. EXPERIMENTAL APPROACH Whole-cell patch clamp recordings were used to examine the effects of TRPV1-active compounds on rat dorsal root ganglion low voltage-activated calcium currents and recombinant Cav 3 isoforms in expression systems. KEY RESULTS The classical TRPV1 agonist capsaicin as well as TRPV1 antagonists A-889425, BCTC, and capsazepine directly inhibited Cav 3 channels. These compounds altered the voltage-dependence of activation and inactivation of Cav 3 channels and delayed their recovery from inactivation, leading to a concomitant decrease in T-type current availability. The TRPV1 antagonist capsazepine potently inhibited Cav 3.1 and 3.2 channels (KD < 120 nM), as demonstrated by its slow off rate. In contrast, neither the TRPV1 agonists, Palvanil and resiniferatoxin, nor the TRPV1 antagonist AMG9810 modulated Cav 3-mediated currents. CONCLUSIONS AND IMPLICATIONS Analgesic TRPV1-active compounds inhibit Cav 3 currents in native and heterologous systems. Hence, their analgesic effects may not be exclusively attributed to their actions on TRPV1, which has important implications in the current understanding of nociceptive pathways. Importantly, our results highlight the need for attention in the experimental design used to address the analgesic properties of Cav 3 channel inhibitors.
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Affiliation(s)
- Jeffrey R McArthur
- Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, NSW, Australia
| | - Rocio K Finol-Urdaneta
- Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, NSW, Australia
| | - David J Adams
- Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, NSW, Australia
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