251
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Furue M, Kadono T. New therapies for controlling atopic itch. J Dermatol 2016; 42:847-50. [PMID: 26332459 DOI: 10.1111/1346-8138.13060] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 06/30/2015] [Indexed: 12/17/2022]
Abstract
Chronic itch in atopic dermatitis markedly diminishes the quality of life of affected individuals. Sleep disturbance and impaired productivity in work due to chronic itch impose a socioeconomic burden. Conventional therapies for atopic dermatitis are capable of reducing atopic itch. However, the majority of patients are not satisfied with the antipruritic capacity of conventional treatments. In this review, we summarize recent progress in itch signaling in the skin, dorsal root ganglion and spinal cord. New therapies for controlling atopic itch are also discussed.
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Affiliation(s)
- Masutaka Furue
- Department of Dermatology, Kyushu University, Fukuoka, Japan
| | - Takafumi Kadono
- Department of Dermatology, St Marianna University School of Medicine, Kawasaki, Japan
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252
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Tian B, Wang XL, Huang Y, Chen LH, Cheng RX, Zhou FM, Guo R, Li JC, Liu T. Peripheral and spinal 5-HT receptors participate in cholestatic itch and antinociception induced by bile duct ligation in rats. Sci Rep 2016; 6:36286. [PMID: 27824106 PMCID: PMC5099756 DOI: 10.1038/srep36286] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Accepted: 10/13/2016] [Indexed: 12/19/2022] Open
Abstract
Although 5-HT has been implicated in cholestatic itch and antinociception, two common phenomena in patients with cholestatic disease, the roles of 5-HT receptor subtypes are unclear. Herein, we investigated the roles of 5-HT receptors in itch and antinociception associated with cholestasis, which was induced by common bile duct ligation (BDL) in rats. 5-HT-induced enhanced scratching and antinociception to mechanical and heat stimuli were demonstrated in BDL rats. 5-HT level in the skin and spinal cord was significantly increased in BDL rats. Quantitative RT-PCR analysis showed 5-HT1B, 5-HT1D, 5-HT2A, 5-HT3A, 5-HT5B, 5-HT6, and 5-HT7 were up-regulated in peripheral nervous system and 5-HT1A, 5-HT1F, 5-HT2B, and 5-HT3A were down-regulated in the spinal cord of BDL rats. Intradermal 5-HT2, 5-HT3, and 5-HT7 receptor agonists induced scratching in BDL rats, whereas 5-HT3 agonist did not induce scratching in sham rats. 5-HT1A, 5-HT2, 5-HT3, and 5-HT7 agonists or antagonists suppressed itch in BDL rats. 5-HT1A agonist attenuated, but 5-HT1A antagonist enhanced antinociception in BDL rats. 5-HT2 and 5-HT3 agonists or antagonists attenuated antinociception in BDL rats. Our data suggested peripheral and central 5-HT system dynamically participated in itch and antinociception under cholestasis condition and targeting 5-HT receptors may be an effective treatment for cholestatic itch.
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Affiliation(s)
- Bin Tian
- Department of General Surgery, The Second Affiliated Hospital of Soochow University, Suzhou, 215004, China
| | - Xue-Long Wang
- Department of General Surgery, The Second Affiliated Hospital of Soochow University, Suzhou, 215004, China
| | - Ya Huang
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases, Institute of Neuroscience, Soochow University, Suzhou, Jiangsu, 215123, China
| | - Li-Hua Chen
- Jiangsu Key Laboratory of Preventive and Translational Medicine for Geriatric Diseases, School of Public Health, Soochow University, Suzhou, 215123, China
| | - Ruo-Xiao Cheng
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases, Institute of Neuroscience, Soochow University, Suzhou, Jiangsu, 215123, China
| | - Feng-Ming Zhou
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases, Institute of Neuroscience, Soochow University, Suzhou, Jiangsu, 215123, China
| | - Ran Guo
- Department of Anesthesiology, The First Affiliated Hospital of Soochow University, Suzhou, 215006, China
| | - Jun-Cheng Li
- Department of General Surgery, The Second Affiliated Hospital of Soochow University, Suzhou, 215004, China
| | - Tong Liu
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases, Institute of Neuroscience, Soochow University, Suzhou, Jiangsu, 215123, China
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253
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Zhou FM, Cheng RX, Wang S, Huang Y, Gao YJ, Zhou Y, Liu TT, Wang XL, Chen LH, Liu T. Antioxidants Attenuate Acute and Chronic Itch: Peripheral and Central Mechanisms of Oxidative Stress in Pruritus. Neurosci Bull 2016; 33:423-435. [PMID: 27783328 DOI: 10.1007/s12264-016-0076-z] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Accepted: 08/27/2016] [Indexed: 12/12/2022] Open
Abstract
Itch (pruritus) is one of the most disabling syndromes in patients suffering from skin, liver, or kidney diseases. Our previous study highlighted a key role of oxidative stress in acute itch. Here, we evaluated the effects of antioxidants in mouse models of acute and chronic itch and explored the potential mechanisms. The effects of systemic administration of the antioxidants N-acetyl-L-cysteine (NAC) and N-tert-butyl-α-phenylnitrone (PBN) were determined by behavioral tests in mouse models of acute itch induced by compound 48/80 or chloroquine, and chronic itch by treatment with a mixture of acetone-diethyl-ether-water. We found that systemic administration of NAC or PBN significantly alleviated compound 48/80- and chloroquine-induced acute itch in a dose-dependent manner, attenuated dry skin-induced chronic itch, and suppressed oxidative stress in the affected skin. Antioxidants significantly decreased the accumulation of intracellular reactive oxygen species directly induced by compound 48/80 and chloroquine in the cultured dorsal root ganglia-derived cell line ND7-23. Finally, the antioxidants remarkably inhibited the compound 48/80-induced phosphorylation of extracellular signal-regulated kinase in the spinal cord. These results indicated that oxidative stress plays a critical role in acute and chronic itch in the periphery and spinal cord and antioxidant treatment may be a promising strategy for anti-itch therapy.
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Affiliation(s)
- Feng-Ming Zhou
- Department of Neurology, The Second Affiliated Hospital of Soochow University, Suzhou, 215004, China.,Institute of Neuroscience, Soochow University, Suzhou, 215123, China
| | - Ruo-Xiao Cheng
- Department of Neurology, The Second Affiliated Hospital of Soochow University, Suzhou, 215004, China.,Institute of Neuroscience, Soochow University, Suzhou, 215123, China
| | - Shuai Wang
- Department of Neurology, The Second Affiliated Hospital of Soochow University, Suzhou, 215004, China.,Jiangsu Key Laboratory of Preventive and Translational Medicine for Geriatric Diseases, Department of Nutrition and Food Hygiene, School of Public Health, Soochow University, Suzhou, 215123, China
| | - Ya Huang
- Institute of Neuroscience, Soochow University, Suzhou, 215123, China
| | - Yong-Jing Gao
- Institute of Nautical Medicine, Nantong University, Nantong, 226001, China
| | - Yan Zhou
- Institute of Neuroscience, Soochow University, Suzhou, 215123, China
| | - Teng-Teng Liu
- Institute of Neuroscience, Soochow University, Suzhou, 215123, China
| | - Xue-Long Wang
- Beijing Electric Power Hospital, Beijing, 100073, China
| | - Li-Hua Chen
- Jiangsu Key Laboratory of Preventive and Translational Medicine for Geriatric Diseases, Department of Nutrition and Food Hygiene, School of Public Health, Soochow University, Suzhou, 215123, China.
| | - Tong Liu
- Department of Neurology, The Second Affiliated Hospital of Soochow University, Suzhou, 215004, China. .,Institute of Neuroscience, Soochow University, Suzhou, 215123, China.
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254
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Li ZW, Wu B, Ye P, Tan ZY, Ji YH. Brain natriuretic peptide suppresses pain induced by BmK I, a sodium channel-specific modulator, in rats. J Headache Pain 2016; 17:90. [PMID: 27687165 PMCID: PMC5042912 DOI: 10.1186/s10194-016-0685-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2016] [Accepted: 09/24/2016] [Indexed: 12/30/2022] Open
Abstract
Background A previous study found that brain natriuretic peptide (BNP) inhibited inflammatory pain via activating its receptor natriuretic peptide receptor A (NPRA) in nociceptive sensory neurons. A recent study found that functional NPRA is expressed in almost all the trigeminal ganglion (TG) neurons at membrane level suggesting a potentially important role for BNP in migraine pathophysiology. Methods An inflammatory pain model was produced by subcutaneous injection of BmK I, a sodium channel-specific modulator from venom of Chinese scorpion Buthus martensi Karsch. Quantitative PCR, Western Blot, and immunohistochemistry were used to detect mRNA and protein expression of BNP and NPRA in dorsal root ganglion (DRG) and dorsal horn of spinal cord. Whole-cell patch clamping experiments were conducted to record large-conductance Ca2+-activated K+ (BKCa) currents of membrane excitability of DRG neurons. Spontaneous and evoked pain behaviors were examined. Results The mRNA and protein expression of BNP and NPRA was up-regulated in DRG and dorsal horn of spinal cord after BmK I injection. The BNP and NPRA was preferentially expressed in small-sized DRG neurons among which BNP was expressed in both CGRP-positive and IB4-positive neurons while NPRA was preferentially expressed in CGRP-positive neurons. BNP increased the open probability of BKCa channels and suppressed the membrane excitability of small-sized DRG neurons. Intrathecal injection of BNP significantly inhibited BmK-induced pain behaviors including both spontaneous and evoked pain behaviors. Conclusions These results suggested that BNP might play an important role as an endogenous pain reliever in BmK I-induced inflammatory pain condition. It is also suggested that BNP might play a similar role in other pathophysiological pain conditions including migraine.
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Affiliation(s)
- Zheng-Wei Li
- Laboratory of Neuropharmacology and Neurotoxicology, Shanghai University, Nanchen Road 333, Shanghai, 200436, People's Republic of China
| | - Bin Wu
- Laboratory of Neuropharmacology and Neurotoxicology, Shanghai University, Nanchen Road 333, Shanghai, 200436, People's Republic of China
| | - Pin Ye
- Laboratory of Neuropharmacology and Neurotoxicology, Shanghai University, Nanchen Road 333, Shanghai, 200436, People's Republic of China
| | - Zhi-Yong Tan
- Department of Pharmacology and Toxicology and Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, 46202, USA.
| | - Yong-Hua Ji
- Laboratory of Neuropharmacology and Neurotoxicology, Shanghai University, Nanchen Road 333, Shanghai, 200436, People's Republic of China.
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255
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Hoeck EA, Marker JB, Gazerani P, H. Andersen H, Arendt-Nielsen L. Preclinical and human surrogate models of itch. Exp Dermatol 2016; 25:750-7. [DOI: 10.1111/exd.13078] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/11/2016] [Indexed: 11/29/2022]
Affiliation(s)
- Emil A. Hoeck
- SMI; Department of Health Science and Technology; Faculty of Medicine; Aalborg University; Aalborg E Denmark
| | - Jens B. Marker
- SMI; Department of Health Science and Technology; Faculty of Medicine; Aalborg University; Aalborg E Denmark
| | - Parisa Gazerani
- SMI; Department of Health Science and Technology; Faculty of Medicine; Aalborg University; Aalborg E Denmark
| | - Hjalte H. Andersen
- SMI; Department of Health Science and Technology; Faculty of Medicine; Aalborg University; Aalborg E Denmark
| | - Lars Arendt-Nielsen
- SMI; Department of Health Science and Technology; Faculty of Medicine; Aalborg University; Aalborg E Denmark
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256
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Effects of Intrathecal κ-Opioid Receptor Agonist on Morphine-Induced Itch and Antinociception in Mice. Reg Anesth Pain Med 2016; 41:69-74. [PMID: 26587674 DOI: 10.1097/aap.0000000000000326] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
The μ-opioid receptor (MOR) agonist-induced itch is a significant issue associated with analgesic therapies. Research suggested that systemically administered κ-opioid receptor (KOR) agonists inhibit intrathecal morphine-induced itch in primates. However, serious adverse effects induced by systemically administered KOR agonists may restrict their usefulness in humans. We investigated the effects of intrathecal KOR agonists on intrathecal morphine-mediated itch and antinociception in mice.Mice received intrathecal injections of one of the following drugs: morphine (0.1-1.0 nmol), the selective KOR agonist TRK-820 100 pmol, the combination of morphine 0.3 nmol + TRK-820 (10-100 pmol), and 5 μL of saline. One hour after intraperitoneal administration of the selective KOR antagonist nor-binaltorphimine 1.0 μmol, the effect of TRK-820 100 pmol on intrathecal morphine 0.3 nmol-induced scratching was tested. Total numbers of scratches after intrathecal injection were analyzed. After observing scratching behavior, sedation level was evaluated subjectively. Nociceptive threshold was determined by tail immersion test with intrathecal injections of the following agents: morphine (0.1-1.0 nmol), TRK-820 (10-100 pmol), morphine 0.1 nmol + TRK-820 10 pmol, and 5 μL of saline.Intrathecal TRK-820 dose-dependently inhibited intrathecal morphine-induced scratching compared with that in the saline group. Intraperitoneal nor-binaltorphimine completely inhibited the antiscratching effect of intrathecal TRK-820 100 pmol. The combination of morphine 0.3 nmol and TRK-820 did not alter the sedation score compared with that in the morphine 0.3 nmol group. Morphine 0.1 nmol + TRK-820 10 pmol significantly produced greater thermal antinociceptive effects than morphine 0.1 nmol.We demonstrated that intrathecal KOR agonists exert antipruritic effects on intrathecal morphine-induced itch without affecting sedation. The combination of intrathecal morphine and intrathecal KOR agonists produces more potent antinociceptive effects against a thermal stimulus compared with morphine alone.
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257
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Abstract
This chapter summarizes recent findings regarding the central transmission of acute and chronic itch. Itch is transduced by cutaneous pruriceptors that transmit signals to neurons in the superficial spinal cord. Spinal itch-signaling circuits utilize several neuropeptides whose receptors represent novel targets to block itch transmission. Itch is relieved by scratching, which activates spinal interneurons to inhibit itch-transmitting neurons. Spinal itch transmission is also thought to be modulated by descending pathways. Itch is transmitted rostrally via ascending pathways to activate a variety of brain regions involved in sensory discrimination of affective and motor responses to itch. The pathophysiological mechanisms of chronic itch are poorly understood but likely involve sensitization of itch-signaling pathways and/or dysfunction of itch-inhibitory circuits. Improved understanding of central itch mechanisms has identified a number of novel targets for the development of antipruritic treatment strategies.
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258
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Abstract
A multitude of exogenous environmental stimuli and endogenous molecular and cellular components interface directly or indirectly with the free nerve endings of sensory nerves in the skin. Environmental stimuli include substances derived from the microbiome and materials, such as allergens, that otherwise come in contact with the skin. Endogenous stimuli include components of or mediators derived from the epidermal barrier, keratinocytes, mast cells, and additional resident and skin-homing immune cells. The sensation of itch is ultimately provoked by mediators that interact with and activate pruriceptors on the sensory nerve fibers. These peripheral fibers convey signals from the skin to the dorsal root and trigeminal ganglia and on to the spinal cord and brain where central processing of the itch sensation occurs. A discussion of the nature and sources of itch stimuli and receptors in the periphery form the basis of this chapter. The development of drugs that target these processes is in the process of revolutionizing therapeutic approaches to itch.
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259
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Sanders KM, Nattkemper LA, Yosipovitch G. Advances in understanding itching and scratching: a new era of targeted treatments. F1000Res 2016; 5. [PMID: 27610225 PMCID: PMC4995681 DOI: 10.12688/f1000research.8659.1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 08/15/2016] [Indexed: 01/14/2023] Open
Abstract
Chronic itch is a significant health burden with few effective treatments. As such, itch researchers seek to understand the mechanisms behind itch and to find potential targets for treatment. The field of itch research is dynamic, and many advances have been made so far this decade. In particular, major steps forward include the identification of new peripheral and central itch mediators and modulators, the discovery of greater roles for immune cells and glia in itch transmission, and a focus on the brain processing of itching and scratching. Finally, several new therapeutic interventions for itch have shown success in clinical trials.
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Affiliation(s)
- Kristen M Sanders
- Department of Dermatology, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, 19140, USA
| | - Leigh A Nattkemper
- Department of Dermatology, Lewis Katz School of Medicine, Temple University, Philadelphia, PA, 19140, USA
| | - Gil Yosipovitch
- Department of Dermatology and Itch Center, Miller School of Medicine, University of Miami, Miami, FL, USA
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260
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Inoue A, Uchida H, Nakazawa T, Yamamoto T, Ito S. Phosphorylation of NMDA receptor GluN2B subunit at Tyr1472 is important for trigeminal processing of itch. Eur J Neurosci 2016; 44:2474-2482. [DOI: 10.1111/ejn.13337] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Revised: 07/01/2016] [Accepted: 07/11/2016] [Indexed: 11/29/2022]
Affiliation(s)
- Akitoshi Inoue
- Department of Medical Chemistry; Kansai Medical University; Hirakata 573-1010 Japan
| | - Hitoshi Uchida
- Department of Medical Chemistry; Kansai Medical University; Hirakata 573-1010 Japan
| | - Takanobu Nakazawa
- Drug Innovation Center; Graduate School of Pharmaceutical Science; Osaka University; Suita Japan
| | - Tadashi Yamamoto
- Cell Signal Unit; Okinawa Institute of Science and Technology Graduate University; Okinawa Japan
| | - Seiji Ito
- Department of Medical Chemistry; Kansai Medical University; Hirakata 573-1010 Japan
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261
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Du T, Bar-Hen A, Bhatia JS, Wolpowitz D. Loss of Papillary Dermal Calcitonin Gene Related Peptide-Expressing Neurons Significantly Correlates with Uremic Pruritus. J Invest Dermatol 2016; 136:2323-2325. [PMID: 27448750 DOI: 10.1016/j.jid.2016.06.629] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Revised: 05/11/2016] [Accepted: 06/03/2016] [Indexed: 10/21/2022]
Affiliation(s)
- Tiankai Du
- Department of Dermatology, Boston University, Boston, Massachusetts, USA
| | | | | | - Deon Wolpowitz
- Department of Dermatology, Boston University, Boston, Massachusetts, USA; Department of Dermatopathology, Boston University, Boston, Massachusetts, USA.
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262
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Sapio MR, Goswami SC, Gross JR, Mannes AJ, Iadarola MJ. Transcriptomic analyses of genes and tissues in inherited sensory neuropathies. Exp Neurol 2016; 283:375-395. [PMID: 27343803 DOI: 10.1016/j.expneurol.2016.06.023] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Revised: 06/07/2016] [Accepted: 06/20/2016] [Indexed: 12/18/2022]
Abstract
Inherited sensory neuropathies are caused by mutations in genes affecting either primary afferent neurons, or the Schwann cells that myelinate them. Using RNA-Seq, we analyzed the transcriptome of human and rat DRG and peripheral nerve, which contain sensory neurons and Schwann cells, respectively. We subdivide inherited sensory neuropathies based on expression of the mutated gene in these tissues, as well as in mouse TRPV1 lineage DRG nociceptive neurons, and across 32 human tissues from the Human Protein Atlas. We propose that this comprehensive approach to neuropathy gene expression leads to better understanding of the involved cell types in patients with these disorders. We also characterize the genetic "fingerprint" of both tissues, and present the highly tissue-specific genes in DRG and sciatic nerve that may aid in the development of gene panels to improve diagnostics for genetic neuropathies, and may represent specific drug targets for diseases of these tissues.
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Affiliation(s)
- Matthew R Sapio
- Department of Perioperative Medicine, Clinical Center, NIH, Bethesda, MD, USA
| | - Samridhi C Goswami
- Department of Perioperative Medicine, Clinical Center, NIH, Bethesda, MD, USA
| | - Jacklyn R Gross
- Department of Perioperative Medicine, Clinical Center, NIH, Bethesda, MD, USA
| | - Andrew J Mannes
- Department of Perioperative Medicine, Clinical Center, NIH, Bethesda, MD, USA
| | - Michael J Iadarola
- Department of Perioperative Medicine, Clinical Center, NIH, Bethesda, MD, USA.
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263
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Bell AM, Gutierrez-Mecinas M, Polgár E, Todd AJ. Spinal neurons that contain gastrin-releasing peptide seldom express Fos or phosphorylate extracellular signal-regulated kinases in response to intradermal chloroquine. Mol Pain 2016; 12:12/0/1744806916649602. [PMID: 27270268 PMCID: PMC4937990 DOI: 10.1177/1744806916649602] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Accepted: 04/08/2016] [Indexed: 12/25/2022] Open
Abstract
Background Gastrin-releasing peptide (GRP) is thought to play a role in the itch evoked by intradermal injection of chloroquine. Although some early studies suggested that GRP was expressed in pruriceptive primary afferents, it is now thought that GRP in the spinal cord is derived mainly from a population of excitatory interneurons in lamina II, and it has been suggested that these are involved in the itch pathway. To test this hypothesis, we used the transcription factor Fos and phosphorylation of extracellular signal-regulated kinases (ERK) to look for evidence that interneurons expressing GRP were activated following intradermal injection of chloroquine into the calf, in mice that express enhanced green fluorescent protein (EGFP) in these cells. Results Injection of chloroquine resulted in numerous Fos- or phospho-ERK (pERK) positive cells in the somatotopically appropriate part of the superficial dorsal horn. The proportion of all neurons in this region that showed Fos or pERK was 18% and 21%, respectively. However, among the GRP–EGFP, only 7% were Fos-positive and 3% were pERK-positive. As such, GRP–EGFP cells were significantly less likely than other neurons to express Fos or to phosphorylate ERK. Conclusions Both expression of Fos and phosphorylation of ERK can be used to identify dorsal horn neurons activated by chloroquine injection. However, these results do not support the hypothesis that interneurons expressing GRP are critical components in the itch pathway.
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Affiliation(s)
- Andrew M Bell
- Institute of Neuroscience and Psychology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK School of Veterinary Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Maria Gutierrez-Mecinas
- Institute of Neuroscience and Psychology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Erika Polgár
- Institute of Neuroscience and Psychology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Andrew J Todd
- Institute of Neuroscience and Psychology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
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265
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McGarry S, Burrows S, Ashoorian T, Pallathil T, Ong K, Edgar DW, Wood F. Mental health and itch in burns patients: Potential associations. Burns 2016; 42:763-8. [DOI: 10.1016/j.burns.2016.01.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Revised: 12/10/2015] [Accepted: 01/06/2016] [Indexed: 12/30/2022]
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266
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Electrophysiological properties of brain-natriuretic peptide- and gastrin-releasing peptide-responsive dorsal horn neurons in spinal itch transmission. Neurosci Lett 2016; 627:51-60. [PMID: 27235577 DOI: 10.1016/j.neulet.2016.05.051] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Revised: 05/18/2016] [Accepted: 05/25/2016] [Indexed: 10/21/2022]
Abstract
Spinal itch transmission has been reported to be mediated by at least two neuronal populations in spinal dorsal horn, neurons expressing brain-natriuretic peptide (BNP) receptor (Npra) and gastrin-releasing peptide (GRP) receptor (GRPR). Although Npra-expressing neurons were shown to be upstream of GRPR- expressing neurons in spinal itch transmission, the roles of BNP and GRP in the spinal neurotransmission of histamine-dependent and -independent itch remains unclear. Using in vivo electrophysiology and behavior analysis, this study examined the responses of chloroquine (histamine-independent pruritogen)-responsive and histamine-responsive dorsal horn neurons to spinal applications of BNP and GRP. Electrophysiologically, 9.5% of chloroquine-responsive neurons responded to BNP, 33.3% to GRP, and 4.8% to both, indicating that almost half of chloroquine-responsive neurons were unresponsive to both BNP and GRP. In contrast, histamine-responsive neurons did not respond to spinal BNP application, whereas 30% responded to spinal GRP application, indicating that 70% of histamine-responsive neurons were unresponsive to both BNP and GRP. Behavioral analyses showed differences in the time-course and frequency of scratching responses evoked by intrathecal BNP and GRP. These findings provide evidence that most BNP-Npra and GRP-GRPR signaling involve different pathways of spinal itch transmission, and that multiple neurotransmitters, in addition to BNP and GRP, are involved in spinal itch transmission. The electrophysiological results also suggest that spinal BNP contributes little to histaminergic itch directly.
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267
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Seal RP. Do the distinct synaptic properties of VGLUTs shape pain? Neurochem Int 2016; 98:82-8. [PMID: 27180049 DOI: 10.1016/j.neuint.2016.04.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2016] [Revised: 04/26/2016] [Accepted: 04/28/2016] [Indexed: 11/25/2022]
Abstract
The somatosensory system transmits touch, temperature, itch and pain. Three vesicular glutamate transporter isoforms mediate the release of glutamate throughout the mammalian nervous system with largely non-overlapping distributions and unique roles at the synapse. This review discusses the contribution of each of these essential transporters to circuits underlying pain and other somatosensory behaviors throughout postnatal development and in the adult. A better understanding of the individual contributions of the VGLUT isoforms could provide new avenues for therapeutic intervention.
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Affiliation(s)
- Rebecca P Seal
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA; Department of Otolaryngology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA; Pittsburgh Center for Pain Research, University of Pittsburgh School of Medicine, Pittsburgh, PA, 15213, USA.
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268
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Ostadhadi S, Azimi E, Lerner EA, Dehpour AR. Are itch and scratching the nausea and vomiting of skin? Exp Dermatol 2016; 25:340-3. [PMID: 26739556 PMCID: PMC5445905 DOI: 10.1111/exd.12935] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/19/2015] [Indexed: 12/19/2022]
Abstract
The physiologic similarities between itch and nausea may not be evident initially, but they share the role of repelling irritants and toxins from the body by inducting scratching and vomiting, respectively. In addition, itch and nausea frequently occur together in certain conditions such as uraemia. Here we show that the mechanisms underlying itch and nausea overlap and that advances in either field may influence the identification of novel drug targets, particularly for itch.
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Affiliation(s)
- Sattar Ostadhadi
- Experimental Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran
- Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
- Brain and Spinal Cord Injury Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Ehsan Azimi
- Cutaneous Biology Research Center, Massachusetts General Hospital, Charlestown, MA, USA
| | - Ethan A Lerner
- Cutaneous Biology Research Center, Massachusetts General Hospital, Charlestown, MA, USA
| | - Ahmad-Reza Dehpour
- Experimental Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran
- Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
- Brain and Spinal Cord Injury Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, Iran
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269
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Abstract
Itch is a unique sensation associated with the scratch reflex. Although the scratch reflex plays a protective role in daily life by removing irritants, chronic itch remains a clinical challenge. Despite urgent clinical need, itch has received relatively little research attention and its mechanisms have remained poorly understood until recently. The goal of the present review is to summarize our current understanding of the mechanisms of acute as well as chronic itch and classifications of the primary itch populations in relationship to transient receptor potential (Trp) channels, which play pivotal roles in multiple somatosensations. The convergent involvement of Trp channels in diverse itch signaling pathways suggests that Trp channels may serve as promising targets for chronic itch treatments.
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Affiliation(s)
- Shuohao Sun
- The Solomon H. Snyder Department of Neuroscience, Center for Sensory Biology, Johns Hopkins University, School of Medicine, Baltimore, MD, 21205, USA
| | - Xinzhong Dong
- The Solomon H. Snyder Department of Neuroscience, Center for Sensory Biology, Johns Hopkins University, School of Medicine, Baltimore, MD, 21205, USA.
- Howard Hughes Medical Institute, Johns Hopkins University, School of Medicine, Baltimore, MD, 21205, USA.
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270
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Abstract
UNLABELLED The gastrin-releasing peptide (GRP) and its receptor (GRPR) are important components of itch transmission. Upstream, but not downstream, aspects of GRPR signaling have been investigated extensively. We hypothesize that GRPR signals in part through the PI3Kγ/Akt pathway. We used pharmacological, electrophysiological, and behavioral approaches to further evaluate GRPR downstream signaling pathways. Our data show that GRP directly activates small-size capsaicin-sensitive DRG neurons, an effect that translates into transient calcium flux and membrane depolarization (∼ 20 mV). GRPR activation also induces Akt phosphorylation, a proxy for PI3Kγ activity, in ex vivo naive mouse spinal cords and in GRPR transiently expressing HEK293 cells. The intrathecal injection of GRP led to intense scratching, an effect largely reduced by either GRPR antagonists or PI3Kγ inhibitor. Scratching behavior was also induced by the intrathecal injection of an Akt activator. In a dry skin model of itch, we show that GRPR blockade or PI3Kγ inhibition reversed the scratching behavior. Altogether, these findings are highly suggestive that GRPR is expressed by the central terminals of DRG nociceptive afferents, which transmit itch via the PI3Kγ/Akt pathway. SIGNIFICANCE STATEMENT Itch is the most common symptom of the skin and is related to noncutaneous diseases. It severely impairs patients' quality of life when it becomes chronic and there is no specific or effective available therapy, mainly because itch pathophysiology is not completely elucidated. Our findings indicate that the enzyme PI3Kγ is a key central mediator of itch transmission. Therefore, we suggest PI3Kγ as an attractive target for the development of new anti-pruritic drugs. With this study, we take a step forward in our understanding of the mechanisms underlying the central transmission of itch sensation.
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271
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Ordovas-Montanes J, Rakoff-Nahoum S, Huang S, Riol-Blanco L, Barreiro O, von Andrian UH. The Regulation of Immunological Processes by Peripheral Neurons in Homeostasis and Disease. Trends Immunol 2016; 36:578-604. [PMID: 26431937 DOI: 10.1016/j.it.2015.08.007] [Citation(s) in RCA: 124] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2015] [Revised: 08/13/2015] [Accepted: 08/13/2015] [Indexed: 02/06/2023]
Abstract
The nervous system and the immune system are the principal sensory interfaces between the internal and external environment. They are responsible for recognizing, integrating, and responding to varied stimuli, and have the capacity to form memories of these encounters leading to learned or 'adaptive' future responses. We review current understanding of the cross-regulation between these systems. The autonomic and somatosensory nervous systems regulate both the development and deployment of immune cells, with broad functions that impact on hematopoiesis as well as on priming, migration, and cytokine production. In turn, specific immune cell subsets contribute to homeostatic neural circuits such as those controlling metabolism, hypertension, and the inflammatory reflex. We examine the contribution of the somatosensory system to autoimmune, autoinflammatory, allergic, and infectious processes in barrier tissues and, in this context, discuss opportunities for therapeutic manipulation of neuro-immune interactions.
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Affiliation(s)
- Jose Ordovas-Montanes
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Seth Rakoff-Nahoum
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA 02115, USA; Department of Medicine, Boston Children's Hospital, and Harvard Medical School, Boston, MA 02115, USA
| | - Siyi Huang
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA 02115, USA
| | | | - Olga Barreiro
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Ulrich H von Andrian
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA 02115, USA; Ragon Institute of Massachusetts General Hospital (MGH), Massachusetts Institute of Technology (MIT), and Harvard University, Cambridge, MA 02139, USA.
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272
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A central role for spinal dorsal horn neurons that express neurokinin-1 receptors in chronic itch. Pain 2016; 156:1240-1246. [PMID: 25830923 DOI: 10.1097/j.pain.0000000000000172] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
We investigated roles for spinal neurons expressing the neurokinin-1 receptor (NK1R) and/or gastrin-releasing peptide receptor (GRPR) in a mouse model of ovalbumin (OVA)-induced chronic atopic dermatitis. Mice receiving repeated topical application of OVA exhibited atopic-like skin lesions and behavioral signs of chronic itch including spontaneous scratching, touch-evoked scratching (alloknesis), and enhancement of chloroquine-evoked scratching (hyperknesis). Substance P-saporin (SP-SAP) and bombesin-saporin (BB-SAP) were intrathecally injected into OVA-sensitized mice to neurotoxically ablate NK1R- or GRPR-expressing spinal neurons, respectively. SP-SAP diminished the expression of NK1R in the superficial spinal dorsal horn and significantly attenuated all behavioral signs of chronic itch. BB-SAP reduced the spinal dorsal horn expression of GRPR and significantly attenuated hyperknesis, with no effect on spontaneous scratching or alloknesis. To investigate whether NK1R-expressing spinal neurons project in ascending somatosensory pathways, we performed a double-label study. The retrograde tracer, Fluorogold (FG), was injected into either the somatosensory thalamus or lateral parabrachial nucleus. In the upper cervical (C1-2) spinal cord, most neurons retrogradely labeled with FG were located in the dorsomedial aspect of the superficial dorsal horn. Of FG-labeled spinal neurons, 89% to 94% were double labeled for NK1R. These results indicate that NK1R-expressing spinal neurons play a major role in the expression of symptoms of chronic itch and give rise to ascending somatosensory projections. Gastrin-releasing peptide receptor-expressing spinal neurons contribute to hyperknesis but not to alloknesis or ongoing itch. NK1R-expressing spinal neurons represent a potential target to treat chronic itch.
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273
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Barry DM, Li H, Liu XY, Shen KF, Liu XT, Wu ZY, Munanairi A, Chen XJ, Yin J, Sun YG, Li YQ, Chen ZF. Critical evaluation of the expression of gastrin-releasing peptide in dorsal root ganglia and spinal cord. Mol Pain 2016; 12:12/0/1744806916643724. [PMID: 27068287 PMCID: PMC4972254 DOI: 10.1177/1744806916643724] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Accepted: 02/18/2016] [Indexed: 01/29/2023] Open
Abstract
There are substantial disagreements about the expression of gastrin-releasing peptide (GRP) in sensory neurons and whether GRP antibody cross-reacts with substance P (SP). These concerns necessitate a critical revaluation of GRP expression using additional approaches. Here, we show that a widely used GRP antibody specifically recognizes GRP but not SP. In the spinal cord of mice lacking SP (Tac1 KO), the expression of not only GRP but also other peptides, notably neuropeptide Y (NPY), is significantly diminished. We detected Grp mRNA in dorsal root ganglias using reverse transcription polymerase chain reaction, in situ hybridization and RNA-seq. We demonstrated that Grp mRNA and protein are upregulated in dorsal root ganglias, but not in the spinal cord, of mice with chronic itch. Few GRP+ immunostaining signals were detected in spinal sections following dorsal rhizotomy and GRP+ cell bodies were not detected in dissociated dorsal horn neurons. Ultrastructural analysis further shows that substantially more GRPergic fibers form synaptic contacts with gastrin releasing peptide receptor-positive (GRPR+) neurons than SPergic fibers. Our comprehensive study demonstrates that a majority of GRPergic fibers are of primary afferent origin. A number of factors such as low copy number of Grp transcripts, small percentage of cells expressing Grp, and the use of an eGFP GENSAT transgenic as a surrogate for GRP protein have contributed to the controversy. Optimization of experimental procedures facilitates the specific detection of GRP expression in dorsal root ganglia neurons.
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Affiliation(s)
- Devin M Barry
- Center for the Study of Itch, Washington University School of Medicine, St. Louis, MO, USA Departments of Anesthesiology, Washington University School of Medicine, St. Louis, MO, USA
| | - Hui Li
- Center for the Study of Itch, Washington University School of Medicine, St. Louis, MO, USA Department of Anatomy, K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, PR China
| | - Xian-Yu Liu
- Center for the Study of Itch, Washington University School of Medicine, St. Louis, MO, USA Departments of Anesthesiology, Washington University School of Medicine, St. Louis, MO, USA
| | - Kai-Feng Shen
- Center for the Study of Itch, Washington University School of Medicine, St. Louis, MO, USA Department of Neurosurgery, Xinqiao Hospital, Third Military Medical University, Chongqing, PR China
| | - Xue-Ting Liu
- Center for the Study of Itch, Washington University School of Medicine, St. Louis, MO, USA Guangdong Provincial Key Laboratory of Allergy & Clinical Immunology, The State Key Laboratory of Respiratory Disease, The Second Affiliated Hospital, Guangzhou Medical University, Guangdong, PR China
| | - Zhen-Yu Wu
- Department of Anatomy, K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, PR China
| | - Admire Munanairi
- Center for the Study of Itch, Washington University School of Medicine, St. Louis, MO, USA Departments of Anesthesiology, Washington University School of Medicine, St. Louis, MO, USA
| | - Xiao-Jun Chen
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Jun Yin
- Center for the Study of Itch, Washington University School of Medicine, St. Louis, MO, USA Departments of Anesthesiology, Washington University School of Medicine, St. Louis, MO, USA
| | - Yan-Gang Sun
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Yun-Qing Li
- Department of Anatomy, K. K. Leung Brain Research Centre, The Fourth Military Medical University, Xi'an, PR China
| | - Zhou-Feng Chen
- Center for the Study of Itch, Washington University School of Medicine, St. Louis, MO, USA Departments of Anesthesiology, Washington University School of Medicine, St. Louis, MO, USA Departments of Psychiatry, Center for the Study of Itch, Washington University School of Medicine, St. Louis, MO, USA Departments of Developmental Biology, Center for the Study of Itch, Washington University School of Medicine, St. Louis, MO, USA
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274
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Chen Y, Fang Q, Wang Z, Zhang JY, MacLeod AS, Hall RP, Liedtke WB. Transient Receptor Potential Vanilloid 4 Ion Channel Functions as a Pruriceptor in Epidermal Keratinocytes to Evoke Histaminergic Itch. J Biol Chem 2016; 291:10252-62. [PMID: 26961876 PMCID: PMC4858974 DOI: 10.1074/jbc.m116.716464] [Citation(s) in RCA: 93] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Indexed: 12/25/2022] Open
Abstract
TRPV4 ion channels function in epidermal keratinocytes and in innervating sensory neurons; however, the contribution of the channel in either cell to neurosensory function remains to be elucidated. We recently reported TRPV4 as a critical component of the keratinocyte machinery that responds to ultraviolet B (UVB) and functions critically to convert the keratinocyte into a pain-generator cell after excess UVB exposure. One key mechanism in keratinocytes was increased expression and secretion of endothelin-1, which is also a known pruritogen. Here we address the question of whether TRPV4 in skin keratinocytes functions in itch, as a particular form of “forefront” signaling in non-neural cells. Our results support this novel concept based on attenuated scratching behavior in response to histaminergic (histamine, compound 48/80, endothelin-1), not non-histaminergic (chloroquine) pruritogens in Trpv4 keratinocyte-specific and inducible knock-out mice. We demonstrate that keratinocytes rely on TRPV4 for calcium influx in response to histaminergic pruritogens. TRPV4 activation in keratinocytes evokes phosphorylation of mitogen-activated protein kinase, ERK, for histaminergic pruritogens. This finding is relevant because we observed robust anti-pruritic effects with topical applications of selective inhibitors for TRPV4 and also for MEK, the kinase upstream of ERK, suggesting that calcium influx via TRPV4 in keratinocytes leads to ERK-phosphorylation, which in turn rapidly converts the keratinocyte into an organismal itch-generator cell. In support of this concept we found that scratching behavior, evoked by direct intradermal activation of TRPV4, was critically dependent on TRPV4 expression in keratinocytes. Thus, TRPV4 functions as a pruriceptor-TRP in skin keratinocytes in histaminergic itch, a novel basic concept with translational-medical relevance.
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Affiliation(s)
| | | | | | | | | | | | - Wolfgang B Liedtke
- From the Departments of Neurology, Neurobiology, and Anesthesiology, Duke University Medical Center, Durham, North Carolina 27710 and Neurology Clinics for Headache, Head Pain and Trigeminal Sensory Disorders, Duke University Medical Center, Durham, North Carolina 27705
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275
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Gutierrez-Mecinas M, Furuta T, Watanabe M, Todd AJ. A quantitative study of neurochemically defined excitatory interneuron populations in laminae I-III of the mouse spinal cord. Mol Pain 2016; 12:12/0/1744806916629065. [PMID: 27030714 PMCID: PMC4946630 DOI: 10.1177/1744806916629065] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Accepted: 12/10/2015] [Indexed: 01/12/2023] Open
Abstract
BACKGROUND Excitatory interneurons account for the majority of neurons in laminae I-III, but their functions are poorly understood. Several neurochemical markers are largely restricted to excitatory interneuron populations, but we have limited knowledge about the size of these populations or their overlap. The present study was designed to investigate this issue by quantifying the neuronal populations that express somatostatin (SST), neurokinin B (NKB), neurotensin, gastrin-releasing peptide (GRP) and the γ isoform of protein kinase C (PKCγ), and assessing the extent to which they overlapped. Since it has been reported that calretinin- and SST-expressing cells have different functions, we also looked for co-localisation of calretinin and SST. RESULTS SST, preprotachykinin B (PPTB, the precursor of NKB), neurotensin, PKCγ or calretinin were detected with antibodies, while cells expressing GRP were identified in a mouse line (GRP-EGFP) in which enhanced green fluorescent protein (EGFP) was expressed under control of the GRP promoter. We found that SST-, neurotensin-, PPTB- and PKCγ-expressing cells accounted for 44%, 7%, 12% and 21% of the neurons in laminae I-II, and 16%, 8%, 4% and 14% of those in lamina III, respectively. GRP-EGFP cells made up 11% of the neuronal population in laminae I-II. The neurotensin, PPTB and GRP-EGFP populations showed very limited overlap, and we estimate that between them they account for ~40% of the excitatory interneurons in laminae I-II. SST which is expressed by ~60% of excitatory interneurons in this region, was found in each of these populations, as well as in cells that did not express any of the other peptides. Neurotensin and PPTB were often found in cells with PKCγ, and between them, constituted around 60% of the PKCγ cells. Surprisingly, we found extensive co-localisation of SST and calretinin. CONCLUSIONS These results suggest that cells expressing neurotensin, NKB or GRP form largely non-overlapping sets that are likely to correspond to functional populations. In contrast, SST is widely expressed by excitatory interneurons that are likely to be functionally heterogeneous.
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Affiliation(s)
- Maria Gutierrez-Mecinas
- Institute of Neuroscience and Psychology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
| | - Takahiro Furuta
- Department of Morphological Brain Science, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Masahiko Watanabe
- Department of Anatomy, Hokkaido University School of Medicine, Sapporo, Japan
| | - Andrew J Todd
- Institute of Neuroscience and Psychology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
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276
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Stantcheva KK, Iovino L, Dhandapani R, Martinez C, Castaldi L, Nocchi L, Perlas E, Portulano C, Pesaresi M, Shirlekar KS, de Castro Reis F, Paparountas T, Bilbao D, Heppenstall PA. A subpopulation of itch-sensing neurons marked by Ret and somatostatin expression. EMBO Rep 2016; 17:585-600. [PMID: 26929027 DOI: 10.15252/embr.201540983] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Accepted: 01/26/2016] [Indexed: 01/01/2023] Open
Abstract
Itch, the unpleasant sensation that elicits a desire to scratch, is mediated by specific subtypes of cutaneous sensory neuron. Here, we identify a subpopulation of itch-sensing neurons based on their expression of the receptor tyrosine kinase Ret. We apply flow cytometry to isolate Ret-positive neurons from dorsal root ganglia and detected a distinct population marked by low levels of Ret and absence of isolectin B4 binding. We determine the transcriptional profile of these neurons and demonstrate that they express neuropeptides such as somatostatin (Sst), the NGF receptor TrkA, and multiple transcripts associated with itch. We validate the selective expression of Sst using an Sst-Cre driver line and ablated these neurons by generating mice in which the diphtheria toxin receptor is conditionally expressed from the sensory neuron-specific Avil locus. Sst-Cre::Avil(iDTR) mice display normal nociceptive responses to thermal and mechanical stimuli. However, scratching behavior evoked by interleukin-31 (IL-31) or agonist at the 5HT1F receptor is significantly reduced. Our data provide a molecular signature for a subpopulation of neurons activated by multiple pruritogens.
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Affiliation(s)
| | - Loredana Iovino
- EMBL Mouse Biology Unit, Monterotondo, Italy Molecular Medicine Partnership Unit (MMPU), Heidelberg, Germany
| | | | | | | | | | | | | | | | | | | | | | | | - Paul A Heppenstall
- EMBL Mouse Biology Unit, Monterotondo, Italy Molecular Medicine Partnership Unit (MMPU), Heidelberg, Germany
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277
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Benarroch EE. Dorsal horn circuitry: Complexity and implications for mechanisms of neuropathic pain. Neurology 2016; 86:1060-9. [PMID: 26888981 DOI: 10.1212/wnl.0000000000002478] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
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278
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Ackerman S, Smith LM, Gomes PJ. Ocular itch associated with allergic conjunctivitis: latest evidence and clinical management. Ther Adv Chronic Dis 2016; 7:52-67. [PMID: 26770669 DOI: 10.1177/2040622315612745] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Allergic conjunctivitis is one of the most common allergic conditions worldwide. Its incidence is increasing due to changing climate, pollution, increased pollen loads, and the subject's heightened immunological sensitivity in response to these environmental changes. The pathophysiology predominantly involves immunoglobulin E-related mast-cell activation, with release of histamine and other mediators contributing to the propagation of the response by calling in other immune cells and further inflammation. This article presents the evolution of ocular allergy treatments, from vasoconstrictors, to antihistamines and mast-cell stabilizers, to the dual-acting agents, as well as corticosteroid and immunomodulatory options. Future targets for allergy treatment are also discussed.
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Affiliation(s)
- Stacey Ackerman
- Philadelphia Eye Associates, 1113 Hospital Drive, Suite 302, Willingboro, NJ 08046, USA
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279
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Rogoz K, Aresh B, Freitag FB, Pettersson H, Magnúsdóttir EI, Larsson Ingwall L, Haddadi Andersen H, Franck MCM, Nagaraja C, Kullander K, Lagerström MC. Identification of a Neuronal Receptor Controlling Anaphylaxis. Cell Rep 2016; 14:370-9. [DOI: 10.1016/j.celrep.2015.12.033] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Revised: 10/20/2015] [Accepted: 12/03/2015] [Indexed: 12/31/2022] Open
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280
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A Spinal Circuit for Mechanically-Evoked Itch. Trends Neurosci 2016; 39:1-2. [DOI: 10.1016/j.tins.2015.12.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 12/02/2015] [Accepted: 12/04/2015] [Indexed: 12/17/2022]
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281
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Stull C, Lavery MJ, Yosipovitch G. Advances in therapeutic strategies for the treatment of pruritus. Expert Opin Pharmacother 2015; 17:671-87. [DOI: 10.1517/14656566.2016.1127355] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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282
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Li CL, Li KC, Wu D, Chen Y, Luo H, Zhao JR, Wang SS, Sun MM, Lu YJ, Zhong YQ, Hu XY, Hou R, Zhou BB, Bao L, Xiao HS, Zhang X. Somatosensory neuron types identified by high-coverage single-cell RNA-sequencing and functional heterogeneity. Cell Res 2015; 26:83-102. [PMID: 26691752 DOI: 10.1038/cr.2015.149] [Citation(s) in RCA: 249] [Impact Index Per Article: 27.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Revised: 11/04/2015] [Accepted: 12/01/2015] [Indexed: 11/09/2022] Open
Abstract
Sensory neurons are distinguished by distinct signaling networks and receptive characteristics. Thus, sensory neuron types can be defined by linking transcriptome-based neuron typing with the sensory phenotypes. Here we classify somatosensory neurons of the mouse dorsal root ganglion (DRG) by high-coverage single-cell RNA-sequencing (10 950 ± 1 218 genes per neuron) and neuron size-based hierarchical clustering. Moreover, single DRG neurons responding to cutaneous stimuli are recorded using an in vivo whole-cell patch clamp technique and classified by neuron-type genetic markers. Small diameter DRG neurons are classified into one type of low-threshold mechanoreceptor and five types of mechanoheat nociceptors (MHNs). Each of the MHN types is further categorized into two subtypes. Large DRG neurons are categorized into four types, including neurexophilin 1-expressing MHNs and mechanical nociceptors (MNs) expressing BAI1-associated protein 2-like 1 (Baiap2l1). Mechanoreceptors expressing trafficking protein particle complex 3-like and Baiap2l1-marked MNs are subdivided into two subtypes each. These results provide a new system for cataloging somatosensory neurons and their transcriptome databases.
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Affiliation(s)
- Chang-Lin Li
- Institute of Neuroscience and State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 20031, China
| | - Kai-Cheng Li
- Institute of Neuroscience and State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 20031, China
| | - Dan Wu
- Institute of Neuroscience and State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 20031, China
| | - Yan Chen
- Institute of Neuroscience and State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 20031, China
| | - Hao Luo
- School of Life Science and Technology, ShanghaiTec University, Shanghai 200031, China
| | - Jing-Rong Zhao
- Institute of Neuroscience and State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 20031, China
| | - Sa-Shuang Wang
- School of Life Science and Technology, ShanghaiTec University, Shanghai 200031, China
| | - Ming-Ming Sun
- National Engineering Center for Biochip at Shanghai, Shanghai, China
| | - Ying-Jin Lu
- Institute of Neuroscience and State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 20031, China
| | - Yan-Qing Zhong
- Institute of Neuroscience and State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 20031, China
| | - Xu-Ye Hu
- Shanghai Clinical Center, Chinese Academy of Sciences/XuHui Central Hospital, Shanghai, China
| | - Rui Hou
- National Engineering Center for Biochip at Shanghai, Shanghai, China
| | - Bei-Bei Zhou
- National Engineering Center for Biochip at Shanghai, Shanghai, China
| | - Lan Bao
- State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences.,School of Life Science and Technology, ShanghaiTec University, Shanghai 200031, China
| | - Hua-Sheng Xiao
- National Engineering Center for Biochip at Shanghai, Shanghai, China
| | - Xu Zhang
- Institute of Neuroscience and State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 20031, China.,School of Life Science and Technology, ShanghaiTec University, Shanghai 200031, China
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283
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Kiguchi N, Sukhtankar DD, Ding H, Tanaka KI, Kishioka S, Peters CM, Ko MC. Spinal Functions of B-Type Natriuretic Peptide, Gastrin-Releasing Peptide, and Their Cognate Receptors for Regulating Itch in Mice. J Pharmacol Exp Ther 2015; 356:596-603. [PMID: 26669425 DOI: 10.1124/jpet.115.229997] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Accepted: 12/14/2015] [Indexed: 12/13/2022] Open
Abstract
B-type natriuretic peptide (BNP)-natriuretic peptide receptor A (NPRA) and gastrin-releasing peptide (GRP)-GRP receptor (GRPR) systems contribute to spinal processing of itch. However, pharmacological and anatomic evidence of these two spinal ligand-receptor systems are still not clear. The aim of this study was to determine the spinal functions of BNP-NPRA and GRP-GRPR systems for regulating scratching activities in mice by using pharmacological and immunohistochemical approaches. Our results showed that intrathecal administration of BNP (0.3-3 nmol) dose dependently elicited scratching responses, which could be blocked by the NPRA antagonist (Arg6,β-cyclohexyl-Ala8,D-Tic16,Arg17,Cys18)-atrial natriuretic factor(6-18) amide (A71915). However, A71915 had no effect on intrathecal GRP-induced scratching. In contrast, pretreatment with a GRPR antagonist (D-Tpi6,Leu13ψ(CH2-NH)-Leu14)bombesin(6-14) (RC-3095) inhibited BNP-induced scratching. Immunostaining revealed that NPRA proteins colocalize with GRP, but not GRPR, in the superficial area of dorsal horn, whereas BNP proteins do not colocalize with either GRP or GRPR in the dorsal horn. Intradermal administration of ligands including endothelin-1, U-46619, bovine adrenal medulla 8-22, and Ser-Leu-Ile-Gly-Arg-Leu-NH2 (SLIGRL) increased scratching bouts at different levels of magnitude. Pretreatment with intrathecal A71915 did not affect scratching responses elicited by all four pruritogens, whereas pretreatment with RC-3095 only inhibited SLIGRL-induced scratching. Interestingly, immunostaining showed that RC-3095, but not A71915, inhibited SLIGRL-elicited c-Fos activation in the spinal dorsal horn, which was in line with behavioral outcomes. These findings demonstrate that: 1) BNP-NPRA system may function upstream of the GRP-GRPR system to regulate itch in the mouse spinal cord, and 2) both NPRA and GRPR antagonists may have antipruritic efficacy against centrally, but not peripherally, elicited itch.
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Affiliation(s)
- Norikazu Kiguchi
- Department of Physiology and Pharmacology (N.K., D.D.S., H.D., M.-C.K.) and Department of Anesthesiology (C.M.P.), Wake Forest University School of Medicine, Winston-Salem, North Carolina; Department of Physiology and Pharmacology, Saitama Prefectural University, Saitama, Japan (K.T.); Department of Pharmacology, Wakayama Medical University, Wakayama, Japan (S.K.)
| | - Devki D Sukhtankar
- Department of Physiology and Pharmacology (N.K., D.D.S., H.D., M.-C.K.) and Department of Anesthesiology (C.M.P.), Wake Forest University School of Medicine, Winston-Salem, North Carolina; Department of Physiology and Pharmacology, Saitama Prefectural University, Saitama, Japan (K.T.); Department of Pharmacology, Wakayama Medical University, Wakayama, Japan (S.K.)
| | - Huiping Ding
- Department of Physiology and Pharmacology (N.K., D.D.S., H.D., M.-C.K.) and Department of Anesthesiology (C.M.P.), Wake Forest University School of Medicine, Winston-Salem, North Carolina; Department of Physiology and Pharmacology, Saitama Prefectural University, Saitama, Japan (K.T.); Department of Pharmacology, Wakayama Medical University, Wakayama, Japan (S.K.)
| | - Ken-ichi Tanaka
- Department of Physiology and Pharmacology (N.K., D.D.S., H.D., M.-C.K.) and Department of Anesthesiology (C.M.P.), Wake Forest University School of Medicine, Winston-Salem, North Carolina; Department of Physiology and Pharmacology, Saitama Prefectural University, Saitama, Japan (K.T.); Department of Pharmacology, Wakayama Medical University, Wakayama, Japan (S.K.)
| | - Shiroh Kishioka
- Department of Physiology and Pharmacology (N.K., D.D.S., H.D., M.-C.K.) and Department of Anesthesiology (C.M.P.), Wake Forest University School of Medicine, Winston-Salem, North Carolina; Department of Physiology and Pharmacology, Saitama Prefectural University, Saitama, Japan (K.T.); Department of Pharmacology, Wakayama Medical University, Wakayama, Japan (S.K.)
| | - Christopher M Peters
- Department of Physiology and Pharmacology (N.K., D.D.S., H.D., M.-C.K.) and Department of Anesthesiology (C.M.P.), Wake Forest University School of Medicine, Winston-Salem, North Carolina; Department of Physiology and Pharmacology, Saitama Prefectural University, Saitama, Japan (K.T.); Department of Pharmacology, Wakayama Medical University, Wakayama, Japan (S.K.)
| | - Mei-Chuan Ko
- Department of Physiology and Pharmacology (N.K., D.D.S., H.D., M.-C.K.) and Department of Anesthesiology (C.M.P.), Wake Forest University School of Medicine, Winston-Salem, North Carolina; Department of Physiology and Pharmacology, Saitama Prefectural University, Saitama, Japan (K.T.); Department of Pharmacology, Wakayama Medical University, Wakayama, Japan (S.K.)
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284
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Bourane S, Duan B, Koch SC, Dalet A, Britz O, Garcia-Campmany L, Kim E, Cheng L, Ghosh A, Ma Q, Goulding M. Gate control of mechanical itch by a subpopulation of spinal cord interneurons. Science 2015; 350:550-4. [PMID: 26516282 DOI: 10.1126/science.aac8653] [Citation(s) in RCA: 187] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Light mechanical stimulation of hairy skin can induce a form of itch known as mechanical itch. This itch sensation is normally suppressed by inputs from mechanoreceptors; however, in many forms of chronic itch, including alloknesis, this gating mechanism is lost. Here we demonstrate that a population of spinal inhibitory interneurons that are defined by the expression of neuropeptide Y::Cre (NPY::Cre) act to gate mechanical itch. Mice in which dorsal NPY::Cre-derived neurons are selectively ablated or silenced develop mechanical itch without an increase in sensitivity to chemical itch or pain. This chronic itch state is histamine-independent and is transmitted independently of neurons that express the gastrin-releasing peptide receptor. Thus, our studies reveal a dedicated spinal cord inhibitory pathway that gates the transmission of mechanical itch.
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Affiliation(s)
- Steeve Bourane
- Molecular Neurobiology Laboratory, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Bo Duan
- Dana-Farber Cancer Institute and Department of Neurobiology, Harvard Medical School, 1 Jimmy Fund Way, Boston, MA 02115, USA
| | - Stephanie C Koch
- Molecular Neurobiology Laboratory, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Antoine Dalet
- Molecular Neurobiology Laboratory, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Olivier Britz
- Molecular Neurobiology Laboratory, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Lidia Garcia-Campmany
- Molecular Neurobiology Laboratory, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Euiseok Kim
- Neurobiology Section, Division of Biological Sciences, University of California, San Diego, CA 92093, USA
| | - Longzhen Cheng
- Dana-Farber Cancer Institute and Department of Neurobiology, Harvard Medical School, 1 Jimmy Fund Way, Boston, MA 02115, USA. Institute of Brain Science and State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai 200032, China
| | - Anirvan Ghosh
- Neurobiology Section, Division of Biological Sciences, University of California, San Diego, CA 92093, USA
| | - Qiufu Ma
- Dana-Farber Cancer Institute and Department of Neurobiology, Harvard Medical School, 1 Jimmy Fund Way, Boston, MA 02115, USA.
| | - Martyn Goulding
- Molecular Neurobiology Laboratory, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA.
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285
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Bader M, Alenina N, Andrade-Navarro MA, Santos RA. MAS and its related G protein-coupled receptors, Mrgprs. Pharmacol Rev 2015; 66:1080-105. [PMID: 25244929 DOI: 10.1124/pr.113.008136] [Citation(s) in RCA: 131] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The Mas-related G protein-coupled receptors (Mrgprs or Mas-related genes) comprise a subfamily of receptors named after the first discovered member, Mas. For most Mrgprs, pruriception seems to be the major function based on the following observations: 1) they are relatively promiscuous in their ligand specificity with best affinities for itch-inducing substances; 2) they are expressed in sensory neurons and mast cells in the skin, the main cellular components of pruriception; and 3) they appear in evolution first in tetrapods, which have arms and legs necessary for scratching to remove parasites or other noxious substances from the skin before they create harm. Because parasites coevolved with hosts, each species faced different parasitic challenges, which may explain another striking observation, the multiple independent duplication and expansion events of Mrgpr genes in different species as a consequence of parallel adaptive evolution. Their predominant expression in dorsal root ganglia anticipates additional functions of Mrgprs in nociception. Some Mrgprs have endogenous ligands, such as β-alanine, alamandine, adenine, RF-amide peptides, or salusin-β. However, because the functions of these agonists are still elusive, the physiologic role of the respective Mrgprs needs to be clarified. The best studied Mrgpr is Mas itself. It was shown to be a receptor for angiotensin-1-7 and to exert mainly protective actions in cardiovascular and metabolic diseases. This review summarizes the current knowledge about Mrgprs, their evolution, their ligands, their possible physiologic functions, and their therapeutic potential.
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Affiliation(s)
- Michael Bader
- Max-Delbrück-Center for Molecular Medicine, Berlin, Germany (M.B., N.A., M.A.A.-N.); Charité-University Medicine, Berlin, Germany (M.B.); Institute for Biology, University of Lübeck, Lübeck, Germany (M.B.); and Department of Physiology and Biophysics, Federal University of Minas Gerais, Belo Horizonte, Brazil (M.B., N.A., R.A.S.)
| | - Natalia Alenina
- Max-Delbrück-Center for Molecular Medicine, Berlin, Germany (M.B., N.A., M.A.A.-N.); Charité-University Medicine, Berlin, Germany (M.B.); Institute for Biology, University of Lübeck, Lübeck, Germany (M.B.); and Department of Physiology and Biophysics, Federal University of Minas Gerais, Belo Horizonte, Brazil (M.B., N.A., R.A.S.)
| | - Miguel A Andrade-Navarro
- Max-Delbrück-Center for Molecular Medicine, Berlin, Germany (M.B., N.A., M.A.A.-N.); Charité-University Medicine, Berlin, Germany (M.B.); Institute for Biology, University of Lübeck, Lübeck, Germany (M.B.); and Department of Physiology and Biophysics, Federal University of Minas Gerais, Belo Horizonte, Brazil (M.B., N.A., R.A.S.)
| | - Robson A Santos
- Max-Delbrück-Center for Molecular Medicine, Berlin, Germany (M.B., N.A., M.A.A.-N.); Charité-University Medicine, Berlin, Germany (M.B.); Institute for Biology, University of Lübeck, Lübeck, Germany (M.B.); and Department of Physiology and Biophysics, Federal University of Minas Gerais, Belo Horizonte, Brazil (M.B., N.A., R.A.S.)
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286
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Cowan A, Lyu RM, Chen YH, Dun SL, Chang JK, Dun NJ. Phoenixin: A candidate pruritogen in the mouse. Neuroscience 2015; 310:541-8. [PMID: 26415767 DOI: 10.1016/j.neuroscience.2015.09.055] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Revised: 09/21/2015] [Accepted: 09/21/2015] [Indexed: 12/15/2022]
Abstract
Phoenixin (PNX) is a 14-amino acid amidated peptide (PNX-14) or an N-terminal extended 20-residue amidated peptide (PNX-20) recently identified in neural and non-neural tissue. Mass spectrometry analysis identified a major peak corresponding to PNX-14, with negligible PNX-20, in mouse spinal cord extracts. Using a previously characterized antiserum that recognized both PNX-14 and PNX-20, PNX-immunoreactivity (irPNX) was detected in a population of dorsal root ganglion (DRG) cells and in cell processes densely distributed to the superficial layers of the dorsal horn; irPNX cell processes were also detected in the skin. The retrograde tracer, Fluorogold, injected subcutaneously (s.c.) to the back of the cervical and thoracic spinal cord of mice, labeled a population of DRG, some of which were also irPNX. PNX-14 (2, 4 and 8 mg/kg) injected s.c.to the nape of the neck provoked dose-dependent repetitive scratching bouts directed to the back of the neck with the hindpaws. The number of scratching bouts varied from 16 to 95 in 30 min, commencing within 5 min post-injection and lasted 10-15 min. Pretreatment of mice at -20 min with nalfurafine (20 μg/kg, s.c.), the kappa opioid receptor agonist, significantly reduced the number of bouts induced by PNX-14 (4 mg/kg) compared with that of saline-pretreated mice. Our results suggest that the peptide, PNX-14, serves as one of the endogenous signal molecules transducing itch sensation in the mouse.
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Affiliation(s)
- A Cowan
- Department of Pharmacology, Temple University School of Medicine, Philadelphia, PA 19140, USA; Center for Substance Abuse Research, Temple University School of Medicine, Philadelphia, PA 19140, USA
| | - R-M Lyu
- Phoenix Pharmaceuticals Inc., Burlingame, CA 94010, USA
| | - Y-H Chen
- Graduate Institute of Acupuncture Science, China Medical University, Taichung, Taiwan
| | - S L Dun
- Department of Pharmacology, Temple University School of Medicine, Philadelphia, PA 19140, USA
| | - J-K Chang
- Phoenix Pharmaceuticals Inc., Burlingame, CA 94010, USA
| | - N J Dun
- Department of Pharmacology, Temple University School of Medicine, Philadelphia, PA 19140, USA.
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287
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Ji RR. Neuroimmune interactions in itch: Do chronic itch, chronic pain, and chronic cough share similar mechanisms? Pulm Pharmacol Ther 2015; 35:81-6. [PMID: 26351759 DOI: 10.1016/j.pupt.2015.09.001] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Revised: 08/27/2015] [Accepted: 09/01/2015] [Indexed: 12/30/2022]
Abstract
Itch and pain are closely related but also clearly distinct sensations. Pain is known to suppress itch, while analgesics such as morphine can provoke itch. However, in pathological and chronic conditions, pain and itch also have similarities. Dysfunction of the nervous system, as manifested by neural plastic changes in primary sensory neurons of the peripheral nervous system (peripheral sensitization) and spinal cord and brain stem neurons in the central nervous system (central sensitization) will result in chronic pain and itch. Importantly, these diseases also result from immune dysfunction, since inflammatory mediators can directly activate or sensitize nociceptive and pruriceptive neurons in the peripheral and central nervous system, leading to pain and itch hypersensitivity. In this mini-review, I discuss the roles of Toll-like receptors (TLRs), transient receptor potential ankyrin 1 (TRPA1) ion channel, and Nav1.7 sodium channel in regulating itch and inflammation, with special emphasis of neuronal TLR signaling and the interaction of TLR7 and TRPA1. Chronic pain and chronic itch are debilitating diseases and dramatically impact the life quality of patients. Targeting TLRs for the control of inflammation, neuroinflammation (inflammation restricted in the nervous system), and hyperexcitability of nociceptors and pruriceptors will lead to new therapeutics for the relief of chronic pain and chronic itch. Finally, given the shared mechanisms among chronic cough, chronic pain, and chronic itch and the demonstrated efficacy of the neuropathic pain drug gabapentin in treating chronic cough, novel therapeutics targeting TRPA1, Nav1.7, and TLRs may also help to alleviate refractory cough via modulating neuron-immune interaction.
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Affiliation(s)
- Ru-Rong Ji
- Department of Anesthesiology, Duke University Medical Center, Durham, NC, 27710, USA; Department of Neurobiology, Duke University Medical Center, Durham, NC, 27710, USA.
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288
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Luo J, Feng J, Liu S, Walters ET, Hu H. Molecular and cellular mechanisms that initiate pain and itch. Cell Mol Life Sci 2015; 72:3201-23. [PMID: 25894692 PMCID: PMC4534341 DOI: 10.1007/s00018-015-1904-4] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Revised: 03/20/2015] [Accepted: 04/07/2015] [Indexed: 12/17/2022]
Abstract
Somatosensory neurons mediate our sense of touch. They are critically involved in transducing pain and itch sensations under physiological and pathological conditions, along with other skin-resident cells. Tissue damage and inflammation can produce a localized or systemic sensitization of our senses of pain and itch, which can facilitate our detection of threats in the environment. Although acute pain and itch protect us from further damage, persistent pain and itch are debilitating. Recent exciting discoveries have significantly advanced our knowledge of the roles of membrane-bound G protein-coupled receptors and ion channels in the encoding of information leading to pain and itch sensations. This review focuses on molecular and cellular events that are important in early stages of the biological processing that culminates in our senses of pain and itch.
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Affiliation(s)
- Jialie Luo
- Department of Anesthesiology, The Center for the Study of Itch, Washington University School of Medicine, 660 S. Euclid Ave., St. Louis, MO, 63110, USA
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289
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Akiyama T, Nagamine M, Davoodi A, Iodi Carstens M, Cevikbas F, Steinhoff M, Carstens E. Intradermal endothelin-1 excites bombesin-responsive superficial dorsal horn neurons in the mouse. J Neurophysiol 2015; 114:2528-34. [PMID: 26311187 DOI: 10.1152/jn.00723.2015] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Accepted: 08/24/2015] [Indexed: 01/21/2023] Open
Abstract
Endothelin-1 (ET-1) has been implicated in nonhistaminergic itch. Here we used electrophysiological methods to investigate whether mouse superficial dorsal horn neurons respond to intradermal (id) injection of ET-1 and whether ET-1-sensitive neurons additionally respond to other pruritic and algesic stimuli or spinal superfusion of bombesin, a homolog of gastrin-releasing peptide (GRP) that excites spinal itch-signaling neurons. Single-unit recordings were made from lumbar dorsal horn neurons in pentobarbital-anesthetized C57BL/6 mice. We searched for units that exhibited elevated firing after id injection of ET-1 (1 μg/μl). Responsive units were further tested with mechanical stimuli, bombesin (spinal superfusion, 200 μg·ml(-1)·min(-1)), heating, cooling, and additional chemicals [histamine, chloroquine, allyl isothiocyanate (AITC), capsaicin]. Of 40 ET-1-responsive units, 48% responded to brush and pinch [wide dynamic range (WDR)] and 52% to pinch only [high threshold (HT)]. Ninety-three percent responded to noxious heat, 50% to cooling, and >70% to histamine, chloroquine, AITC, and capsaicin. Fifty-seven percent responded to bombesin, suggesting that they participate in spinal itch transmission. That most ET-1-sensitive spinal neurons also responded to pruritic and algesic stimuli is consistent with previous studies of pruritogen-responsive dorsal horn neurons. We previously hypothesized that pruritogen-sensitive neurons signal itch. The observation that ET-1 activates nociceptive neurons suggests that both itch and pain signals may be generated by ET-1 to result in simultaneous sensations of itch and pain, consistent with observations that ET-1 elicits both itch- and pain-related behaviors in animals and burning itch sensations in humans.
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Affiliation(s)
- T Akiyama
- Department of Neurobiology, Physiology, and Behavior, University of California, Davis, California
| | - M Nagamine
- Department of Neurobiology, Physiology, and Behavior, University of California, Davis, California
| | - A Davoodi
- Department of Neurobiology, Physiology, and Behavior, University of California, Davis, California
| | - M Iodi Carstens
- Department of Neurobiology, Physiology, and Behavior, University of California, Davis, California
| | - F Cevikbas
- Departments of Dermatology and Surgery, University of California, San Francisco, California; and
| | - M Steinhoff
- Department of Dermatology and Charles Institute for Translational Dermatology, University College Dublin, Dublin, Ireland
| | - E Carstens
- Department of Neurobiology, Physiology, and Behavior, University of California, Davis, California;
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290
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Neurochemical characterization of pERK-expressing spinal neurons in histamine-induced itch. Sci Rep 2015; 5:12787. [PMID: 26248539 PMCID: PMC4650701 DOI: 10.1038/srep12787] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Accepted: 07/08/2015] [Indexed: 12/27/2022] Open
Abstract
Acute itch is divided into histamine- and non-histamine-dependent subtypes, and our previous study has shown that activation of ERK signaling in the spinal dorsal horn (SDH) is required selectively for histamine-induced itch sensation. Morphological characteristics of pERK-expressing neurons are required for exploring the mechanism underlying spinal itch sensation. To investigate whether pERK-expressing neurons are supraspinally-projecting neurons, we injected Fluorogold (FG) into the ventrobasal thalamic complex (VB) and parabrachial region, the two major spinal ascending sites in rodents. A small number (1%) of pERK-positive neurons were labeled by FG, suggesting that histamine-induced activation of ERK is primarily located in local SDH neurons. We then examined the co-localization of pERK with Calbindin and Lmx1b, which are expressed by excitatory neurons, and found that more than half (58%) of pERK-positive neurons expressed Lmx1b, but no co-expression with Calbindin was observed. On the other hand, approximately 7% of pERK-positive neurons expressed GAD67, and 27% of them contained Pax2. These results support the idea that pERK-expressing neurons serve as a component of local neuronal circuits for processing itch sensation in the spinal cord.
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291
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Shiratori-Hayashi M, Koga K, Tozaki-Saitoh H, Kohro Y, Toyonaga H, Yamaguchi C, Hasegawa A, Nakahara T, Hachisuka J, Akira S, Okano H, Furue M, Inoue K, Tsuda M. STAT3-dependent reactive astrogliosis in the spinal dorsal horn underlies chronic itch. Nat Med 2015; 21:927-31. [PMID: 26193341 DOI: 10.1038/nm.3912] [Citation(s) in RCA: 131] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Accepted: 06/26/2015] [Indexed: 12/19/2022]
Abstract
Chronic itch is an intractable symptom of inflammatory skin diseases, such as atopic and contact dermatitis. Recent studies have revealed neuronal pathways selective for itch, but the mechanisms by which itch turns into a pathological chronic state are poorly understood. Using mouse models of atopic and contact dermatitis, we demonstrate a long-term reactive state of astrocytes in the dorsal horn of the spinal segments that corresponds to lesioned, itchy skin. We found that reactive astrogliosis depended on the activation of signal transducer and activator of transcription 3 (STAT3). Conditional disruption of astrocytic STAT3 suppressed chronic itch, and pharmacological inhibition of spinal STAT3 ameliorated the fully developed chronic itch. Mice with atopic dermatitis exhibited an increase in scratching elicited by intrathecal administration of the itch-inducer gastrin-releasing peptide (GRP), and this enhancement was normalized by suppressing STAT3-mediated reactive astrogliosis. Moreover, we identified lipocalin-2 (LCN2) as an astrocytic STAT3-dependent upregulated factor that was crucial for chronic itch, and we demonstrated that intrathecal administration of LCN2 to normal mice increased spinal GRP-evoked scratching. Our findings indicate that STAT3-dependent reactive astrocytes act as critical amplifiers of itching through a mechanism involving the enhancement of spinal itch signals by LCN2, thereby providing a previously unrecognized target for treating chronic itch.
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Affiliation(s)
- Miho Shiratori-Hayashi
- 1] Department of Life Innovation, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan. [2] Department of Molecular and System Pharmacology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Keisuke Koga
- 1] Department of Life Innovation, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan. [2] Department of Molecular and System Pharmacology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Hidetoshi Tozaki-Saitoh
- 1] Department of Life Innovation, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan. [2] Department of Molecular and System Pharmacology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Yuta Kohro
- Department of Molecular and System Pharmacology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Honami Toyonaga
- 1] Department of Life Innovation, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan. [2] Department of Molecular and System Pharmacology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Chiharu Yamaguchi
- 1] Department of Life Innovation, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan. [2] Department of Molecular and System Pharmacology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Ayumi Hasegawa
- Department of Molecular and System Pharmacology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Takeshi Nakahara
- Department of Dermatology, Graduate School of Medicine, Kyushu University, Fukuoka, Japan
| | - Junichi Hachisuka
- Department of Dermatology, Graduate School of Medicine, Kyushu University, Fukuoka, Japan
| | - Shizuo Akira
- 1] Laboratory of Host Defense, WPI Immunology Frontier Research Center (IFReC), Osaka University, Osaka, Japan. [2] Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
| | - Hideyuki Okano
- Department of Physiology, Keio University School of Medicine, Tokyo, Japan
| | - Masutaka Furue
- Department of Dermatology, Graduate School of Medicine, Kyushu University, Fukuoka, Japan
| | - Kazuhide Inoue
- Department of Molecular and System Pharmacology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Makoto Tsuda
- 1] Department of Life Innovation, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan. [2] Department of Molecular and System Pharmacology, Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
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292
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Akiyama T, Curtis E, Nguyen T, Carstens MI, Carstens E. Anatomical evidence of pruriceptive trigeminothalamic and trigeminoparabrachial projection neurons in mice. J Comp Neurol 2015; 524:244-56. [PMID: 26099199 DOI: 10.1002/cne.23839] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2014] [Revised: 06/05/2015] [Accepted: 06/08/2015] [Indexed: 11/06/2022]
Abstract
Itch is relayed to higher centers by projection neurons in the spinal and medullary dorsal horn. We employed a double-label method to map the ascending projections of pruriceptive and nociceptive trigeminal and spinal neurons. The retrograde tracer fluorogold (FG) was stereotaxically injected into the right thalamus or lateral parabrachial area (LPb) in mice. Seven days later, mice received intradermal (id) microinjection of histamine, chloroquine, capsaicin, or vehicle into the left cheek. Histamine, chloroquine, and capsaicin intradermally elicited similar distributions of Fos-positive neurons in the medial aspect of the superficial medullary and spinal dorsal horn from the trigeminal subnucleus caudalis to C2. Among neurons retrogradely labeled from the thalamus, 43%, 8%, and 22% were Fos-positive following id histamine, chloroquine, or capsaicin. Among the Fos-positive neurons following pruritic or capsaicin stimuli, ∼1-2% were retrogradely labeled with FG. Trigeminoparabrachial projection neurons exhibited a higher incidence of double labeling in the superficial dorsal horn. Among the neurons retrogradely labeled from LPb, 36%, 29%, and 33% were Fos positive following id injection of histamine, chloroquine, and capsaicin, respectively. Among Fos-positive neurons elicited by id histamine, chloroquine, and capsaicin, respectively, 3.7%, 4.3%, and 4.1% were retrogradely labeled from LPb. The present results indicate that, overall, relatively small subpopulations of pruriceptive and/or nociceptive neurons innervating the cheek project to thalamus or LPb. These results imply that the vast majority of pruritogen- and algogen-responsive spinal neurons are likely to function as interneurons relaying information to projection neurons and/or participating in segmental nocifensive circuits.
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Affiliation(s)
- Tasuku Akiyama
- Temple Itch Center, Department of Dermatology, Department of Anatomy and Cell Biology, Temple University School of Medicine, Philadelphia, Pennsylvania, 19140
| | - Eric Curtis
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, Davis, California, 95616
| | - Tony Nguyen
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, Davis, California, 95616
| | - Mirela Iodi Carstens
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, Davis, California, 95616
| | - E Carstens
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, Davis, California, 95616
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293
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Ding H, Hayashida K, Suto T, Sukhtankar DD, Kimura M, Mendenhall V, Ko MC. Supraspinal actions of nociceptin/orphanin FQ, morphine and substance P in regulating pain and itch in non-human primates. Br J Pharmacol 2015; 172:3302-12. [PMID: 25752320 PMCID: PMC4500367 DOI: 10.1111/bph.13124] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Revised: 02/20/2015] [Accepted: 02/25/2015] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND AND PURPOSE Nociceptin/orphanin FQ (N/OFQ) peptide (NOP) receptor agonists display a promising analgesic profile in preclinical studies. However, supraspinal N/OFQ produced hyperalgesia in rodents and such effects have not been addressed in primates. Thus, the aim of this study was to investigate the effects of centrally administered ligands on regulating pain and itch in non-human primates. In particular, nociceptive thresholds affected by intracisternal N/OFQ were compared with those of morphine and substance P, known to provide analgesia and mediate hyperalgesia, respectively, in humans. EXPERIMENTAL APPROACH Intrathecal catheters were installed to allow intracisternal and lumbar intrathecal administration in awake and unanaesthetized rhesus monkeys. Nociceptive responses were measured using the warm water tail-withdrawal assay. Itch scratching responses were scored from videotapes recording behavioural activities of monkeys in their home cages. Antagonist studies were conducted to validate the receptor mechanisms underlying intracisternally elicited behavioural responses. KEY RESULTS Intracisternal morphine (100 nmol) elicited more head scratches than those after intrathecal morphine. Distinct dermatomal scratching locations between the two routes suggest a corresponding activation of supraspinal and spinal μ receptors. Unlike intracisternal substance P, which induced hyperalgesia, intracisternal N/OFQ (100 nmol) produced antinociceptive effects mediated by NOP receptors. Neither peptide increased scratching responses. CONCLUSIONS AND IMPLICATIONS Taken together, these results demonstrated differential actions of ligands in the primate supraspinal region in regulating pain and itch. This study not only improves scientific understanding of the N/OFQ-NOP receptor system in pain processing but also supports the therapeutic potential of NOP-related ligands as analgesics.
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Affiliation(s)
- H Ding
- Department of Physiology and Pharmacology, Wake Forest University School of MedicineWinston-Salem, NC, USA
| | - K Hayashida
- Department of Anesthesiology, Wake Forest University School of MedicineWinston-Salem, NC, USA
| | - T Suto
- Department of Anesthesiology, Wake Forest University School of MedicineWinston-Salem, NC, USA
| | - D D Sukhtankar
- Department of Physiology and Pharmacology, Wake Forest University School of MedicineWinston-Salem, NC, USA
| | - M Kimura
- Department of Anesthesiology, Wake Forest University School of MedicineWinston-Salem, NC, USA
| | - V Mendenhall
- Preclinical Translational Services, Wake Forest University School of MedicineWinston-Salem, NC, USA
| | - M C Ko
- Department of Physiology and Pharmacology, Wake Forest University School of MedicineWinston-Salem, NC, USA
- Department of Dermatology, Wake Forest University School of MedicineWinston-Salem, NC, USA
- Center for Comparative Medicine Research, Wake Forest University School of MedicineWinston-Salem, NC, USA
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294
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Fostini AC, Girolomoni G. Experimental elicitation of itch: Evoking and evaluation techniques. J Dermatol Sci 2015; 80:13-7. [PMID: 26095137 DOI: 10.1016/j.jdermsci.2015.06.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Accepted: 06/10/2015] [Indexed: 01/20/2023]
Abstract
Itch is a very common symptom of many skin diseases. Chronic itch may be very troublesome and may strongly impact on work ability, sleep and on the quality of life. Many studies have been conducted to define peripheral and central itch pathways, and to test the anti-pruritic effect of drugs, in which pruritus was experimentally evoked by chemical mediators and by physical stimuli. However, no objective methods to reproduce and to evaluate itch has been standardized. In this review we summarize the experimental techniques used to induce pruritus and to quantify it both in animal models and in humans.
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Affiliation(s)
- Anna Chiara Fostini
- Department of Medicine, Section of Dermatology and Venereology, University of Verona, 37126, Verona, Italy.
| | - Giampiero Girolomoni
- Department of Medicine, Section of Dermatology and Venereology, University of Verona, 37126, Verona, Italy
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295
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Morita T, McClain SP, Batia LM, Pellegrino M, Wilson SR, Kienzler MA, Lyman K, Olsen ASB, Wong JF, Stucky CL, Brem RB, Bautista DM. HTR7 Mediates Serotonergic Acute and Chronic Itch. Neuron 2015; 87:124-38. [PMID: 26074006 DOI: 10.1016/j.neuron.2015.05.044] [Citation(s) in RCA: 129] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Revised: 03/31/2015] [Accepted: 05/18/2015] [Indexed: 12/13/2022]
Abstract
Chronic itch is a prevalent and debilitating condition for which few effective therapies are available. We harnessed the natural variation across genetically distinct mouse strains to identify transcripts co-regulated with itch behavior. This survey led to the discovery of the serotonin receptor HTR7 as a key mediator of serotonergic itch. Activation of HTR7 promoted opening of the ion channel TRPA1, which in turn triggered itch behaviors. In addition, acute itch triggered by serotonin or a selective serotonin reuptake inhibitor required both HTR7 and TRPA1. Aberrant serotonin signaling has long been linked to a variety of human chronic itch conditions, including atopic dermatitis. In a mouse model of atopic dermatitis, mice lacking HTR7 or TRPA1 displayed reduced scratching and skin lesion severity. These data highlight a role for HTR7 in acute and chronic itch and suggest that HTR7 antagonists may be useful for treating a variety of pathological itch conditions.
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Affiliation(s)
- Takeshi Morita
- Department of Molecular & Cell Biology, 142 Life Sciences Addition, University of California, Berkeley, Berkeley, CA 94720-3200, USA; Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Shannan P McClain
- Department of Molecular & Cell Biology, 142 Life Sciences Addition, University of California, Berkeley, Berkeley, CA 94720-3200, USA
| | - Lyn M Batia
- Department of Molecular & Cell Biology, 142 Life Sciences Addition, University of California, Berkeley, Berkeley, CA 94720-3200, USA
| | - Maurizio Pellegrino
- Department of Molecular & Cell Biology, 142 Life Sciences Addition, University of California, Berkeley, Berkeley, CA 94720-3200, USA
| | - Sarah R Wilson
- Department of Molecular & Cell Biology, 142 Life Sciences Addition, University of California, Berkeley, Berkeley, CA 94720-3200, USA; Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Michael A Kienzler
- Neurobiology Course, Marine Biological Laboratory, Woods Hole, MA 02543, USA
| | - Kyle Lyman
- Neurobiology Course, Marine Biological Laboratory, Woods Hole, MA 02543, USA
| | | | - Justin F Wong
- Department of Molecular & Cell Biology, 142 Life Sciences Addition, University of California, Berkeley, Berkeley, CA 94720-3200, USA
| | - Cheryl L Stucky
- Departments of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Rachel B Brem
- Buck Institute for Research on Aging, 8001 Redwood Boulevard, Novato, CA 94945, USA; Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, CA 94720, USA.
| | - Diana M Bautista
- Department of Molecular & Cell Biology, 142 Life Sciences Addition, University of California, Berkeley, Berkeley, CA 94720-3200, USA; Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA 94720, USA.
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296
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Mediators of Chronic Pruritus in Atopic Dermatitis: Getting the Itch Out? Clin Rev Allergy Immunol 2015; 51:263-292. [DOI: 10.1007/s12016-015-8488-5] [Citation(s) in RCA: 200] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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297
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Primary afferent and spinal cord expression of gastrin-releasing peptide: message, protein, and antibody concerns. J Neurosci 2015; 35:648-57. [PMID: 25589759 DOI: 10.1523/jneurosci.2955-14.2015] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
There is continuing controversy relating to the primary afferent neurotransmitter that conveys itch signals to the spinal cord. Here, we investigated the DRG and spinal cord expression of the putative primary afferent-derived "itch" neurotransmitter, gastrin-releasing peptide (GRP). Using ISH, qPCR, and immunohistochemistry, we conclude that GRP is expressed abundantly in spinal cord, but not in DRG neurons. Titration of the most commonly used GRP antiserum in tissues from wild-type and GRP mutant mice indicates that the antiserum is only selective for GRP at high dilutions. Paralleling these observations, we found that a GRPeGFP transgenic reporter mouse has abundant expression in superficial dorsal horn neurons, but not in the DRG. In contrast to previous studies, neither dorsal rhizotomy nor an intrathecal injection of capsaicin, which completely eliminated spinal cord TRPV1-immunoreactive terminals, altered dorsal horn GRP immunoreactivity. Unexpectedly, however, peripheral nerve injury induced significant GRP expression in a heterogeneous population of DRG neurons. Finally, dual labeling and retrograde tracing studies showed that GRP-expressing neurons of the superficial dorsal horn are predominantly interneurons, that a small number coexpress protein kinase C gamma (PKCγ), but that none coexpress the GRP receptor (GRPR). Our studies support the view that pruritogens engage spinal cord "itch" circuits via excitatory superficial dorsal horn interneurons that express GRP and that likely target GRPR-expressing interneurons. The fact that peripheral nerve injury induced de novo GRP expression in DRG neurons points to a novel contribution of this peptide to pruritoceptive processing in neuropathic itch conditions.
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298
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Molecular dissection of itch. Curr Opin Neurobiol 2015; 34:61-6. [PMID: 25700248 DOI: 10.1016/j.conb.2015.01.017] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Revised: 01/26/2015] [Accepted: 01/28/2015] [Indexed: 01/17/2023]
Abstract
There have been many exciting recent advances in our understanding of the molecular and cellular basis of itch. These discoveries cover diverse aspects of itch sensation, from the identification of new receptors to the characterization of spinal cord itch circuits. A common thread of these studies is that they demonstrate that itch sensory signals are segregated from input for other somatosensory modalities, such as pain, touch, and thermosensation. This specificity is achieved by the expression of dedicated receptors and transmitters in a select population of sensory neurons which detect pruritogens. Further, recent studies show that itch specificity is maintained in a spinal cord circuit by the utilization of specific neurotransmitters and cognate receptors to convey input along a distinct cellular pathway.
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299
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Abstract
PURPOSE OF REVIEW To highlight the most recent advances regarding gastrointestinal peptides and their relation to chronic itch, with focus on gastrin-releasing peptide (GRP), substance P, and their respective receptors. RECENT FINDINGS GRP and its high-affinity GRP receptor (GRPR) have been identified as key regulators in the spinal cord itch pathway and may be involved in the maintenance of chronic itch sensation. Several neuropeptides including GRP, neuromedin B, and substance P regulate itch signals in a cooperative or inhibitory manner on the spinal level. Small clinical studies show that neurokinin 1 receptor antagonists might be of benefit in the treatment of chronic itch. SUMMARY Chronic itch is a burdensome clinical problem, for which no specific treatment is available. Studies on the mechanisms of pruriceptive sensation and its signaling to the central nervous system (CNS) via the spinal cord have elucidated a number of peptides that are implicated in the regulation of itch-specific signaling pathways. Among those, GRP and its high-affinity GRP receptor have been proposed as key elements in the itch-specific neuronal pathways.
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Affiliation(s)
- H Christian Weber
- Section of Gastroenterology, Boston University School of Medicine, Boston, Massachusetts, USA
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300
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Jang Y, Lee WJ, Hong GS, Shim WS. Red ginseng extract blocks histamine-dependent itch by inhibition of H1R/TRPV1 pathway in sensory neurons. J Ginseng Res 2015. [PMID: 26199558 PMCID: PMC4506365 DOI: 10.1016/j.jgr.2015.01.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Background Korean Red Ginseng—a steamed root of Panax ginseng Meyer—has long been used as a traditional medicine in Asian countries. Its antipruritic effect was recently found, but no molecular mechanisms were revealed. Thus, the current study focused on determining the underlying molecular mechanism of Korean Red Ginseng extract (RGE) against histamine-induced itch at the peripheral sensory neuronal level. Methods To examine the antipruritic effect of RGE, we performed in vivo scratching behavior test in mice, as well as in vitro calcium imaging and whole-cell patch clamp experiments to elucidate underlying molecular mechanisms. Results The results of our in vivo study confirmed that RGE indeed has an antipruritic effect on histamine-induced scratching in mice. In addition, RGE showed a significant inhibitory effect on histamine-induced responses in primary cultures of mouse dorsal root ganglia, suggesting that RGE has a direct inhibitory effect on sensory neuronal level. Results of further experiments showed that RGE inhibits histamine-induced responses on cells expressing both histamine receptor subtype 1 and TRPV1 ion channel, indicating that RGE blocks the histamine receptor type 1/TRPV1 pathway in sensory neurons, which is responsible for histamine-dependent itch sensation. Conclusion The current study found for the first time that RGE effectively blocks histamine-induced itch in peripheral sensory neurons. We believe that the current results will provide an insight on itch transmission and will be helpful in understanding how RGE exerts its antipruritic effects.
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Affiliation(s)
- Yongwoo Jang
- Sensory Research Center, Creative Research Initiatives, College of Pharmacy, Seoul National University, Seoul, Korea ; Department of Psychiatry and Program in Neuroscience, McLean Hospital, Harvard Medical School, Belmont, MA, USA
| | - Wook-Joo Lee
- College of Pharmacy, Gachon University, Incheon, Korea
| | - Gyu-Sang Hong
- Sensory Research Center, Creative Research Initiatives, College of Pharmacy, Seoul National University, Seoul, Korea
| | - Won-Sik Shim
- College of Pharmacy, Gachon University, Incheon, Korea
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