101
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Abstract
Itch is a unique sensation that helps organisms scratch away external threats; scratching itself induces an immune response that can contribute to more itchiness. Itch is induced chemically in the peripheral nervous system via a wide array of receptors. Given the superficial localization of itch neuron terminals, cells that dwell close to the skin contribute significantly to itch. Certain mechanical stimuli mediated by recently discovered circuits also contribute to the itch sensation. Ultimately, in the spinal cord, and likely in the brain, circuits that mediate touch, pain, and itch engage in cross modulation. Much of itch perception is still a mystery, but we present in this review the known ligands and receptors associated with itch. We also describe experiments and findings from investigations into the spinal and supraspinal circuitry responsible for the sensation of itch.
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Affiliation(s)
- Mark Lay
- The Solomon H. Snyder Department of Neuroscience and the Center for Sensory Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA;,
| | - Xinzhong Dong
- The Solomon H. Snyder Department of Neuroscience and the Center for Sensory Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA;,
- Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
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102
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Zhang D, Men H, Zhang L, Gao X, Wang J, Li L, Zhu Q, Zhang H, Jia Z. Inhibition of M/K v7 Currents Contributes to Chloroquine-Induced Itch in Mice. Front Mol Neurosci 2020; 13:105. [PMID: 32694980 PMCID: PMC7339983 DOI: 10.3389/fnmol.2020.00105] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2019] [Accepted: 05/20/2020] [Indexed: 01/31/2023] Open
Abstract
M/Kv7 potassium channels play a key role in regulation of neuronal excitability. Modulation of neuronal excitability of primary sensory neurons determines the itch sensation induced by a variety of itch-causing substances including chloroquine (CQ). In the present study, we demonstrate that suppression of M/Kv7 channel activity contributes to generation of itch in mice. CQ enhances excitability of the primary sensory neurons through inhibiting M/Kv7 potassium currents in a Ca2+ influx-dependent manner. Specific M/Kv7 channel opener retigabine (RTG) or tannic acid (TA) not only reverses the CQ-induced enhancement of neuronal excitability but also suppresses the CQ-induced itch behavior. Systemic application of RTG or TA also significantly inhibits the itch behavior induced by a variety of pruritogens. Taken together, our findings provide novel insight into the molecular basis of CQ-induced itch sensation in mammals that can be applied to the development of strategies to mitigate itch behavior.
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Affiliation(s)
- Dong Zhang
- Department of Pharmacology, Hebei Medical University, Shijiazhuang, China.,Center for Innovative Drug Research and Evaluation, Institute of Medical Science and Health, Hebei Medical University, Shijiazhuang, China.,The Key Laboratory of Neural and Vascular Biology, Ministry of Education, Shijiazhuang, China.,The Key Laboratory of New Drug Pharmacology and Toxicology, Shijiazhuang, China.,Department of Anesthesiology, Hebei General Hospital, Shijiazhuang, China
| | - Hongchao Men
- Department of Pharmacology, Hebei Medical University, Shijiazhuang, China.,Center for Innovative Drug Research and Evaluation, Institute of Medical Science and Health, Hebei Medical University, Shijiazhuang, China.,The Key Laboratory of Neural and Vascular Biology, Ministry of Education, Shijiazhuang, China.,The Key Laboratory of New Drug Pharmacology and Toxicology, Shijiazhuang, China.,Department of Anesthesiology, Hebei General Hospital, Shijiazhuang, China
| | - Ludi Zhang
- Department of Pharmacology, Hebei Medical University, Shijiazhuang, China.,Center for Innovative Drug Research and Evaluation, Institute of Medical Science and Health, Hebei Medical University, Shijiazhuang, China.,The Key Laboratory of Neural and Vascular Biology, Ministry of Education, Shijiazhuang, China.,The Key Laboratory of New Drug Pharmacology and Toxicology, Shijiazhuang, China
| | - Xiangxin Gao
- Department of Pharmacology, Hebei Medical University, Shijiazhuang, China.,Center for Innovative Drug Research and Evaluation, Institute of Medical Science and Health, Hebei Medical University, Shijiazhuang, China.,The Key Laboratory of Neural and Vascular Biology, Ministry of Education, Shijiazhuang, China.,The Key Laboratory of New Drug Pharmacology and Toxicology, Shijiazhuang, China
| | - Jingjing Wang
- Department of Pharmacology, Hebei Medical University, Shijiazhuang, China.,Center for Innovative Drug Research and Evaluation, Institute of Medical Science and Health, Hebei Medical University, Shijiazhuang, China.,The Key Laboratory of Neural and Vascular Biology, Ministry of Education, Shijiazhuang, China.,The Key Laboratory of New Drug Pharmacology and Toxicology, Shijiazhuang, China
| | - Leying Li
- Department of Pharmacology, Hebei Medical University, Shijiazhuang, China.,Center for Innovative Drug Research and Evaluation, Institute of Medical Science and Health, Hebei Medical University, Shijiazhuang, China.,The Key Laboratory of Neural and Vascular Biology, Ministry of Education, Shijiazhuang, China.,The Key Laboratory of New Drug Pharmacology and Toxicology, Shijiazhuang, China
| | - Qiaoying Zhu
- Department of Pharmacology, Hebei Medical University, Shijiazhuang, China.,Center for Innovative Drug Research and Evaluation, Institute of Medical Science and Health, Hebei Medical University, Shijiazhuang, China.,The Key Laboratory of Neural and Vascular Biology, Ministry of Education, Shijiazhuang, China.,The Key Laboratory of New Drug Pharmacology and Toxicology, Shijiazhuang, China
| | - Hailin Zhang
- Department of Pharmacology, Hebei Medical University, Shijiazhuang, China.,Center for Innovative Drug Research and Evaluation, Institute of Medical Science and Health, Hebei Medical University, Shijiazhuang, China.,The Key Laboratory of Neural and Vascular Biology, Ministry of Education, Shijiazhuang, China.,The Key Laboratory of New Drug Pharmacology and Toxicology, Shijiazhuang, China
| | - Zhanfeng Jia
- Department of Pharmacology, Hebei Medical University, Shijiazhuang, China.,Center for Innovative Drug Research and Evaluation, Institute of Medical Science and Health, Hebei Medical University, Shijiazhuang, China.,The Key Laboratory of Neural and Vascular Biology, Ministry of Education, Shijiazhuang, China.,The Key Laboratory of New Drug Pharmacology and Toxicology, Shijiazhuang, China
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103
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Abstract
Itch, in particular chronic forms, has been widely recognized as an important clinical problem, but much less is known about the mechanisms of itch in comparison with other sensory modalities such as pain. Recently, considerable progress has been made in dissecting the circuit mechanisms of itch at both the spinal and supraspinal levels. Major components of the spinal neural circuit underlying both chemical and mechanical itch have now been identified, along with the circuits relaying ascending transmission and the descending modulation of itch. In this review, we summarize the progress in elucidating the neural circuit mechanism of itch at spinal and supraspinal levels.
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Affiliation(s)
- Xiao-Jun Chen
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Center for Excellence in Brain Science & Intelligence Technology, Chinese Academy of Sciences, 320 Yue-Yang Road, 200031, Shanghai, China
- University of Chinese Academy of Sciences, 19A Yu-quan Road, 100049, Beijing, China
| | - Yan-Gang Sun
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Center for Excellence in Brain Science & Intelligence Technology, Chinese Academy of Sciences, 320 Yue-Yang Road, 200031, Shanghai, China.
- Shanghai Center for Brain Science and Brain-Inspired Intelligence Technology, 201210, Shanghai, China.
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104
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Kumar R, Geron M, Hazan A, Priel A. Endogenous and Exogenous Vanilloids Evoke Disparate TRPV1 Activation to Produce Distinct Neuronal Responses. Front Pharmacol 2020; 11:903. [PMID: 32595512 PMCID: PMC7303340 DOI: 10.3389/fphar.2020.00903] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Accepted: 06/02/2020] [Indexed: 12/19/2022] Open
Abstract
Neuronal signals are processed along the nociceptive pathway to convey discriminative information, which would manifest in the produced pain sensation. The transient receptor potential vanilloid 1 (TRPV1), an important signaling complex in nociceptors termini, is activated by different noxious stimuli that underlie distinct pain sensations. For example, while endovanilloids are associated with inflammatory pain and hypersensitivity through TRPV1 activation, the exovanilloid toxin, capsaicin, evokes an acute pain by activating this channel. Differences in the TRPV1 activation profile evoked by exogenous and endogenous vanilloids were suggested to underlie this disparity in pain sensations. However, the cellular processes that lead to these differences in pain sensation mediated by the same channel are not fully understood. Here, we sought to describe the neuronal response of TRPV1-expressing nociceptors to exo-and endovanilloids. To this end, we performed current-clamp recordings in rat trigeminal neurons exposed to either capsaicin or intracellular endovanilloids produced downstream of the bradykinin receptor BK2. Our results show that lipoxygenase metabolites generate persistent TRPV1-dependent action potential firing while capsaicin evokes robust depolarization and high-frequency firing that is quickly terminated by depolarization block. Additionally, we found that a weak TRPV1 activation prolongs action potential firing. Overall, our results indicate different firing patterns evoked by inflammatory mediators and capsaicin via TRPV1 that correlate with the respective subsequent pain sensation. These findings also suggest that differences in neuronal activation stem from the variable degree of TRPV1 activation they produce.
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Affiliation(s)
- Rakesh Kumar
- Institute for Drug Research (IDR), School of Pharmacy, The Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Matan Geron
- Institute for Drug Research (IDR), School of Pharmacy, The Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Adina Hazan
- Institute for Drug Research (IDR), School of Pharmacy, The Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Avi Priel
- Institute for Drug Research (IDR), School of Pharmacy, The Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
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105
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Neuroinflammatory Gene Expression Pattern Is Similar between Allergic Rhinitis and Atopic Dermatitis but Distinct from Atopic Asthma. BIOMED RESEARCH INTERNATIONAL 2020; 2020:7196981. [PMID: 32596360 PMCID: PMC7305544 DOI: 10.1155/2020/7196981] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 04/22/2020] [Accepted: 05/05/2020] [Indexed: 11/18/2022]
Abstract
Methods In the study, we included 86 children diagnosed with atopic asthma (n = 25), allergic rhinitis (n = 20), and atopic dermatitis (n = 20) and healthy control subjects (n = 21) of Caucasian origin from the Polish population. The blood leukocyte expression of 31 genes involved in neuroinflammatory response (neurotrophins, their receptors, neuropeptides, and histamine signaling pathway) was analysed using TaqMan low-density arrays. The relative expression of selected proteins from plasma was done using TaqMan Protein Assays. Statistical analysis was done using Statistica. Results Blood expression of 31 genes related to neuroimmune interactions showed significant increase in both allergic diseases, allergic rhinitis and atopic dermatitis, in comparison to the control group. We found 12 genes significantly increased in allergic rhinitis and 9 genes in which the expression was elevated in atopic dermatitis. Moreover, 9 genes with changed expression in atopic dermatitis overlapped with those in allergic rhinitis. Atopic asthma showed 5 genes with altered expression. The peripheral expression of neuroinflammatory genes in the human study was verified in target tissues (nasal epithelium and skin) in a rat model of allergic inflammation. Conclusions A common pattern of neuroinflammatory gene expression between allergic rhinitis and atopic dermatitis may reflect similar changes in sensory nerve function during chronic allergic inflammation.
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106
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Platelet-derived growth factor activates nociceptive neurons by inhibiting M-current and contributes to inflammatory pain. Pain 2020; 160:1281-1296. [PMID: 30933959 PMCID: PMC6553959 DOI: 10.1097/j.pain.0000000000001523] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Supplemental Digital Content is Available in the Text. Our work reveals that the platelet-derived growth factor-BB, by inhibiting nociceptive M-type potassium channels, acts as a pain-inducing proinflammatory factor that significantly contributes to inflammatory pain. Endogenous inflammatory mediators contribute to the pathogenesis of pain by acting on nociceptors, specialized sensory neurons that detect noxious stimuli. Here, we describe a new factor mediating inflammatory pain. We show that platelet-derived growth factor (PDGF)-BB applied in vitro causes repetitive firing of dissociated nociceptor-like rat dorsal root ganglion neurons and decreased their threshold for action potential generation. Injection of PDGF-BB into the paw produced nocifensive behavior in rats and led to thermal and mechanical pain hypersensitivity. We further detailed the biophysical mechanisms of these PDGF-BB effects and show that PDGF receptor–induced inhibition of nociceptive M-current underlies PDGF-BB–mediated nociceptive hyperexcitability. Moreover, in vivo sequestration of PDGF or inhibition of the PDGF receptor attenuates acute formalin-induced inflammatory pain. Our discovery of a new pain-facilitating proinflammatory mediator, which by inhibiting M-current activates nociceptive neurons and thus contributes to inflammatory pain, improves our understanding of inflammatory pain pathophysiology and may have important clinical implications for pain treatment.
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107
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The Return of the Mast Cell: New Roles in Neuroimmune Itch Biology. J Invest Dermatol 2020; 140:945-951. [PMID: 32248995 DOI: 10.1016/j.jid.2019.12.011] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Revised: 12/11/2019] [Accepted: 12/17/2019] [Indexed: 01/30/2023]
Abstract
The mast cell-nerve unit classically has represented a fundamental neuroimmune axis in the development of itch because of the traditional prominence of histamine as a pruritogen. However, it is appreciated increasingly that most chronic itch disorders are likely nonhistaminergic in nature, provoking the hypothesis that other novel effector itch mechanisms derived from mast cells are important. In this review, we present an overview of classical mast cell biology and put these concepts into the context of recent advances in our understanding of the regulation and function of the mast cell-nerve unit in itch biology.
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108
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Barry DM, Liu XT, Liu B, Liu XY, Gao F, Zeng X, Liu J, Yang Q, Wilhelm S, Yin J, Tao A, Chen ZF. Exploration of sensory and spinal neurons expressing gastrin-releasing peptide in itch and pain related behaviors. Nat Commun 2020; 11:1397. [PMID: 32170060 PMCID: PMC7070094 DOI: 10.1038/s41467-020-15230-y] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Accepted: 02/27/2020] [Indexed: 12/12/2022] Open
Abstract
Gastrin-releasing peptide (GRP) functions as a neurotransmitter for non-histaminergic itch, but its site of action (sensory neurons vs spinal cord) remains controversial. To determine the role of GRP in sensory neurons, we generated a floxed Grp mouse line. We found that conditional knockout of Grp in sensory neurons results in attenuated non-histaminergic itch, without impairing histamine-induced itch. Using a Grp-Cre knock-in mouse line, we show that the upper epidermis of the skin is exclusively innervated by GRP fibers, whose activation via optogeneics and chemogenetics in the skin evokes itch- but not pain-related scratching or wiping behaviors. In contrast, intersectional genetic ablation of spinal Grp neurons does not affect itch nor pain transmission, demonstrating that spinal Grp neurons are dispensable for itch transmission. These data indicate that GRP is a neuropeptide in sensory neurons for non-histaminergic itch, and GRP sensory neurons are dedicated to itch transmission.
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Affiliation(s)
- Devin M Barry
- Center for the Study of Itch and Sensory Disorders, Washington University School of Medicine, St. Louis, MO, 63110, USA
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Xue-Ting Liu
- Center for the Study of Itch and Sensory Disorders, Washington University School of Medicine, St. Louis, MO, 63110, USA
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO, 63110, USA
- The Second Affiliated Hospital, The State Key Laboratory of Respiratory Disease, Guangdong Provincial Key Laboratory of Allergy & Clinical Immunology, Sino-French Hoffmann Institute, Center for Immunology, Inflammation, Immune-mediated disease, Guangzhou Medical University, 510260, Guangzhou, Guangdong, P.R. China
| | - Benlong Liu
- Center for the Study of Itch and Sensory Disorders, Washington University School of Medicine, St. Louis, MO, 63110, USA
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Xian-Yu Liu
- Center for the Study of Itch and Sensory Disorders, Washington University School of Medicine, St. Louis, MO, 63110, USA
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Fang Gao
- Center for the Study of Itch and Sensory Disorders, Washington University School of Medicine, St. Louis, MO, 63110, USA
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Xiansi Zeng
- Center for the Study of Itch and Sensory Disorders, Washington University School of Medicine, St. Louis, MO, 63110, USA
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO, 63110, USA
- College of Life Sciences, Xinyang Normal University, 237 Nanhu Road, 464000, Xinyang, P. R. China
| | - Juan Liu
- Center for the Study of Itch and Sensory Disorders, Washington University School of Medicine, St. Louis, MO, 63110, USA
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Qianyi Yang
- Center for the Study of Itch and Sensory Disorders, Washington University School of Medicine, St. Louis, MO, 63110, USA
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Steven Wilhelm
- Center for the Study of Itch and Sensory Disorders, Washington University School of Medicine, St. Louis, MO, 63110, USA
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Jun Yin
- Center for the Study of Itch and Sensory Disorders, Washington University School of Medicine, St. Louis, MO, 63110, USA
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Ailin Tao
- Center for the Study of Itch and Sensory Disorders, Washington University School of Medicine, St. Louis, MO, 63110, USA
- The Second Affiliated Hospital, The State Key Laboratory of Respiratory Disease, Guangdong Provincial Key Laboratory of Allergy & Clinical Immunology, Sino-French Hoffmann Institute, Center for Immunology, Inflammation, Immune-mediated disease, Guangzhou Medical University, 510260, Guangzhou, Guangdong, P.R. China
| | - Zhou-Feng Chen
- Center for the Study of Itch and Sensory Disorders, Washington University School of Medicine, St. Louis, MO, 63110, USA.
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO, 63110, USA.
- Department of Psychiatry, Washington University School of Medicine, St. Louis, MO, 63110, USA.
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO, 63110, USA.
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109
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Li WB, Liu S, Zhang MZ, Liu H, Dong XH, Hao Y, Liu YF, Wang YB. Hyperbaric oxygen therapy relieved pruritus and pain of keloid patients. Am J Transl Res 2020; 12:574-582. [PMID: 32194905 PMCID: PMC7061847] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Accepted: 01/17/2020] [Indexed: 06/10/2023]
Abstract
Objective: Keloid patients usually have local pruritus and pain. In our clinical work, we have found keloid patients after receiving hyperbaric oxygen (HBO) therapy reflect less pruritus and pain. The hypothesis was that patients with keloid and a history of HBO therapy would have less pruritus and pain than patients without HBO therapy, and the pruritus or pain-related factors were detected in keloid with/without HBO therapy and normal skin. Methods: Three groups of samples were established: keloid samples from patients with HBO therapy for two weeks before and after surgery (H group); keloid samples from patients without HBO therapy (G group); normal skin samples from patients without obvious scar (N group). Hematoxylin and eosin (H&E) staining was used to observe morphological changes. Pruritus/pain related factors: Tryptophan Hydroxylase1 (TPH1), connexin-43 (Cx43) and transient receptor potential vanilloid type 1 (TRPV1) were detected by immunofluorescence and western blot technology. The expression of these factors' mRNA was also measured by the real-time quantitative polymerase chain reaction (RT-qPCR). Results: Among three groups, G group presented significantly highest expression levels of TPH1, Cx43 and TRPV1, conversely, N group presented significantly lowest expression levels of TPH1, Cx43 and TRPV1. Conclusion: TPH1, Cx43 and TRPV1 were overexpressed in the samples of keloid patients, indicating that the pruritus and pain of keloid might be related to these factors. Furthermore, TPH1, Cx43 and TRPV1 were expressed highest in keloid patients without HBO therapy, indicating that HBO therapy might relief pruritus of keloid patients by regulating these factors.
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Affiliation(s)
- Wen-Bo Li
- Department of Radiology, Peking Union Medical College HospitalBeijing 100730, China
| | - Shu Liu
- Department of General Surgery, Civil Aviation General HospitalBeijing 100028, China
| | - Ming-Zi Zhang
- Department of Plastic Surgery, Peking Union Medical College HospitalBeijing 100730, China
| | - Hao Liu
- Department of Plastic Surgery, Peking Union Medical College HospitalBeijing 100730, China
| | - Xin-Hang Dong
- Department of Plastic Surgery, Peking Union Medical College HospitalBeijing 100730, China
| | - Yan Hao
- Department of Plastic Surgery, Peking Union Medical College HospitalBeijing 100730, China
| | - Yi-Fang Liu
- Beijing Vocational College of AgricultureBeijing 102442, China
| | - You-Bin Wang
- Department of Radiology, Peking Union Medical College HospitalBeijing 100730, China
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110
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Grundy L, Caldwell A, Garcia Caraballo S, Erickson A, Schober G, Castro J, Harrington AM, Brierley SM. Histamine induces peripheral and central hypersensitivity to bladder distension via the histamine H1 receptor and TRPV1. Am J Physiol Renal Physiol 2020; 318:F298-F314. [DOI: 10.1152/ajprenal.00435.2019] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Interstitial cystitis/bladder pain syndrome (IC/BPS) is a common chronic pelvic disorder with sensory symptoms of urinary urgency, frequency, and pain, indicating a key role for hypersensitivity of bladder-innervating sensory neurons. The inflammatory mast cell mediator histamine has long been implicated in IC/BPS, yet the direct interactions between histamine and bladder afferents remain unclear. In the present study, we show, using a mouse ex vivo bladder afferent preparation, that intravesical histamine enhanced the mechanosensitivity of subpopulations of afferents to bladder distension. Histamine also recruited “silent afferents” that were previously unresponsive to bladder distension. Furthermore, in vivo intravesical histamine enhanced activation of dorsal horn neurons within the lumbosacral spinal cord, indicating increased afferent signaling in the central nervous system. Quantitative RT-PCR revealed significant expression of histamine receptor subtypes ( Hrh1– Hrh3) in mouse lumbosacral dorsal root ganglia (DRG), bladder detrusor smooth muscle, mucosa, and isolated urothelial cells. In DRG, Hrh1 was the most abundantly expressed. Acute histamine exposure evoked Ca2+ influx in select populations of DRG neurons but did not elicit calcium transients in isolated primary urothelial cells. Histamine-induced mechanical hypersensitivity ex vivo was abolished in the presence of the histamine H1 receptor antagonist pyrilamine and was not present in preparations from mice lacking transient receptor potential vanilloid 1 (TRPV1). Together, these results indicate that histamine enhances the sensitivity of bladder afferents to distension via interactions with histamine H1 receptor and TRPV1. This hypersensitivity translates to increased sensory input and activation in the spinal cord, which may underlie the symptoms of bladder hypersensitivity and pain experienced in IC/BPS.
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Affiliation(s)
- Luke Grundy
- Visceral Pain Research Group, Centre for Neuroscience, College of Medicine and Public Health, Flinders University, South Australia, Australia
- Hopwood Centre for Neurobiology, Lifelong Health Theme, South Australian Health and Medical Research Institute, Adelaide, South Australia, Australia
- Centre for Nutrition and Gastrointestinal Diseases, Discipline of Medicine, Faculty of Health and Medical Science, University of Adelaide, Adelaide, South Australia, Australia
- Department of Clinical Pharmacology, College of Medicine and Public Health, Flinders University, South Australia, Australia
| | - Ashlee Caldwell
- Visceral Pain Research Group, Centre for Neuroscience, College of Medicine and Public Health, Flinders University, South Australia, Australia
- Hopwood Centre for Neurobiology, Lifelong Health Theme, South Australian Health and Medical Research Institute, Adelaide, South Australia, Australia
- Centre for Nutrition and Gastrointestinal Diseases, Discipline of Medicine, Faculty of Health and Medical Science, University of Adelaide, Adelaide, South Australia, Australia
| | - Sonia Garcia Caraballo
- Visceral Pain Research Group, Centre for Neuroscience, College of Medicine and Public Health, Flinders University, South Australia, Australia
- Hopwood Centre for Neurobiology, Lifelong Health Theme, South Australian Health and Medical Research Institute, Adelaide, South Australia, Australia
- Centre for Nutrition and Gastrointestinal Diseases, Discipline of Medicine, Faculty of Health and Medical Science, University of Adelaide, Adelaide, South Australia, Australia
| | - Andelain Erickson
- Visceral Pain Research Group, Centre for Neuroscience, College of Medicine and Public Health, Flinders University, South Australia, Australia
- Hopwood Centre for Neurobiology, Lifelong Health Theme, South Australian Health and Medical Research Institute, Adelaide, South Australia, Australia
- Centre for Nutrition and Gastrointestinal Diseases, Discipline of Medicine, Faculty of Health and Medical Science, University of Adelaide, Adelaide, South Australia, Australia
| | - Gudrun Schober
- Visceral Pain Research Group, Centre for Neuroscience, College of Medicine and Public Health, Flinders University, South Australia, Australia
- Hopwood Centre for Neurobiology, Lifelong Health Theme, South Australian Health and Medical Research Institute, Adelaide, South Australia, Australia
- Centre for Nutrition and Gastrointestinal Diseases, Discipline of Medicine, Faculty of Health and Medical Science, University of Adelaide, Adelaide, South Australia, Australia
| | - Joel Castro
- Visceral Pain Research Group, Centre for Neuroscience, College of Medicine and Public Health, Flinders University, South Australia, Australia
- Hopwood Centre for Neurobiology, Lifelong Health Theme, South Australian Health and Medical Research Institute, Adelaide, South Australia, Australia
- Centre for Nutrition and Gastrointestinal Diseases, Discipline of Medicine, Faculty of Health and Medical Science, University of Adelaide, Adelaide, South Australia, Australia
| | - Andrea M. Harrington
- Visceral Pain Research Group, Centre for Neuroscience, College of Medicine and Public Health, Flinders University, South Australia, Australia
- Hopwood Centre for Neurobiology, Lifelong Health Theme, South Australian Health and Medical Research Institute, Adelaide, South Australia, Australia
- Centre for Nutrition and Gastrointestinal Diseases, Discipline of Medicine, Faculty of Health and Medical Science, University of Adelaide, Adelaide, South Australia, Australia
| | - Stuart M. Brierley
- Visceral Pain Research Group, Centre for Neuroscience, College of Medicine and Public Health, Flinders University, South Australia, Australia
- Hopwood Centre for Neurobiology, Lifelong Health Theme, South Australian Health and Medical Research Institute, Adelaide, South Australia, Australia
- Centre for Nutrition and Gastrointestinal Diseases, Discipline of Medicine, Faculty of Health and Medical Science, University of Adelaide, Adelaide, South Australia, Australia
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111
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Avila C, Massick S, Kaffenberger BH, Kwatra SG, Bechtel M. Cannabinoids for the treatment of chronic pruritus: A review. J Am Acad Dermatol 2020; 82:1205-1212. [PMID: 31987788 DOI: 10.1016/j.jaad.2020.01.036] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Revised: 01/15/2020] [Accepted: 01/18/2020] [Indexed: 11/17/2022]
Abstract
Medical marijuana is becoming widely available to patients in the United States, and with recreational marijuana now legalized in many states, patient interest is on the rise. The endocannabinoid system plays an important role in skin homeostasis in addition to broader effects on neurogenic responses such as pruritus and nociception, inflammation, and immune reactions. Numerous studies of in vitro and animal models have provided insight into the possible mechanisms of cannabinoid modulation on pruritus, with the most evidence behind neuronal modulation of peripheral itch fibers and centrally acting cannabinoid receptors. In addition, human studies, although limited due to differences in the cannabinoids used, disease models, and delivery method, have consistently shown significant reductions in both scratching and symptoms in chronic pruritus. Clinical studies have shown a reduction in pruritus in several dermatologic (atopic dermatitis, psoriasis, asteatotic eczema, prurigo nodularis, and allergic contact dermatitis) and systemic (uremic pruritus and cholestatic pruritus) diseases. These preliminary human studies warrant controlled trials to confirm the benefit of cannabinoids for treatment of pruritus and to standardize treatment regimens and indications. In patients who have refractory chronic pruritus after standard therapies, cannabinoid formulations may be considered as an adjuvant therapy where it is legal.
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Affiliation(s)
- Christina Avila
- Department of Internal Medicine, The Ohio State University College of Medicine, Columbus, Ohio
| | - Susan Massick
- Division of Dermatology, The Ohio State University Wexner Medical Center, Columbus, Ohio
| | | | - Shawn G Kwatra
- Division of Dermatology, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Mark Bechtel
- Division of Dermatology, The Ohio State University Wexner Medical Center, Columbus, Ohio.
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112
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Jang Y, Kim M, Hwang SW. Molecular mechanisms underlying the actions of arachidonic acid-derived prostaglandins on peripheral nociception. J Neuroinflammation 2020; 17:30. [PMID: 31969159 PMCID: PMC6975075 DOI: 10.1186/s12974-020-1703-1] [Citation(s) in RCA: 126] [Impact Index Per Article: 31.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Accepted: 01/06/2020] [Indexed: 12/30/2022] Open
Abstract
Arachidonic acid-derived prostaglandins not only contribute to the development of inflammation as intercellular pro-inflammatory mediators, but also promote the excitability of the peripheral somatosensory system, contributing to pain exacerbation. Peripheral tissues undergo many forms of diseases that are frequently accompanied by inflammation. The somatosensory nerves innervating the inflamed areas experience heightened excitability and generate and transmit pain signals. Extensive studies have been carried out to elucidate how prostaglandins play their roles for such signaling at the cellular and molecular levels. Here, we briefly summarize the roles of arachidonic acid-derived prostaglandins, focusing on four prostaglandins and one thromboxane, particularly in terms of their actions on afferent nociceptors. We discuss the biosynthesis of the prostaglandins, their specific action sites, the pathological alteration of the expression levels of related proteins, the neuronal outcomes of receptor stimulation, their correlation with behavioral nociception, and the pharmacological efficacy of their regulators. This overview will help to a better understanding of the pathological roles that prostaglandins play in the somatosensory system and to a finding of critical molecular contributors to normalizing pain.
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Affiliation(s)
- Yongwoo Jang
- Department of Psychiatry and Program in Neuroscience, McLean Hospital, Harvard Medical School, Belmont, MA, 02478, USA.,Department of Biomedical Engineering, Hanyang University, Seoul, 04763, South Korea
| | - Minseok Kim
- Department of Biomedical Sciences, Korea University, Seoul, 02841, South Korea
| | - Sun Wook Hwang
- Department of Biomedical Sciences, Korea University, Seoul, 02841, South Korea. .,Department of Physiology, College of Medicine, Korea University, Seoul, 02841, South Korea.
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113
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Abstract
Basic mechanisms and pathways of itch signaling are reviewed, with an emphasis on the progress to date as well as remaining challenges in translating current knowledge to the clinical treatment of chronic itch. Recent studies reveal 3 subsets of pruriceptive sensory neurons highly expressing itch-related genes. Their fibers project into the spinal cord to activate neurons expressing gastrin releasing peptide (GRP) and its receptor (GRPR), which connect to neurons that express the substance P (NK-1) receptor and project to the parabrachial nucleus and thalamus. Spinal inhibitory interneurons release GABA, glycine and dynorphin to modulate segmental itch transmission. However, nearly all pruriceptive neurons also respond to algogens such as capsaicin. Alternative theories of itch-pain discrimination, such as intensity or spatial contrast, are based on the observation that focal stimulation of nociceptive nerve endings elicits itch while more widespread stimulation elicits pain. These findings cloud the issue of a labeled line for itch- a long-debated but currently unresolved challenge. In higher primates there is a dichotomy of histaminergic and non-histaminergic itch-signaling pathways which is less demarcated in rodents, suggesting species differences. A cardinal symptom of chronic itch is alloknesis, i.e., mechanical or touch-evoked itch. Recent evidence indicates that low-threshold mechanosensory afferents can access the spinal itch pathway, but are normally kept in check by inhibitory interneurons expressing neuropeptide Y (NPY). In chronic itch, NPY-mediated inhibition is reduced, allowing touch to excite itch-signaling pathways. These recent advances provide novel targets for development of therapeutic strategies to relieve chronic itch.
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114
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Potenzieri A, Riva B, Genazzani AA. Unexpected Ca 2+-mobilization of oxaliplatin via H1 histamine receptors. Cell Calcium 2019; 86:102128. [PMID: 31841953 DOI: 10.1016/j.ceca.2019.102128] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Revised: 11/20/2019] [Accepted: 11/20/2019] [Indexed: 11/19/2022]
Abstract
Oxaliplatin is a widely used chemotherapeutic drug and represents the cornerstone of colorectal cancer therapy, in combination with 5-fluorouracil and folinic acid. As with many chemotherapeutic agents, its use is associated with a number of side effects, ranging from hypersensitivity reactions to haematological dyscrasias. Oxaliplatin also induces acute and chronic peripheral neuropathy. While it is likely that the haematological side effects are associated with its anti-proliferative effects and with the ability to form DNA adducts, the molecular mechanisms underlying peripheral neuropathy and hypersensitivity reactions are poorly understood, and therefore the choice of adequate supportive therapies is largely empirical. Here we show that an acute low dose oxaliplatin application on DRG neurons is able to induce an increase in intracellular calcium that is dependent on the Histamine 1 receptor (H1). Oxaliplatin-induced intracellular calcium rises are blocked by two selective H1 antagonist, as well as by U73122, a PLC inhibitor, and by 2-APB, a non-specific IP3 receptor blocker. Moreover, expression of the H1 receptor on HEK293 t cells unmasks an oxaliplatin-induced Ca2+-rise. Last, activation of H1 via either histamine or oxaliplatin activates TRPV1 receptors, a mechanism that has been associated with itch. These data, together with literature data that has shown that anti-histamine agents reduce the incidence of oxaliplatin-induced hypersensitivity, may provide a molecular mechanism of this side effect in oncological patients.
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Affiliation(s)
- A Potenzieri
- Department of Pharmaceutical Sciences, Università Del Piemonte Orientale, Via Bovio 6, I-28100 Novara, Italy
| | - B Riva
- Department of Pharmaceutical Sciences, Università Del Piemonte Orientale, Via Bovio 6, I-28100 Novara, Italy
| | - A A Genazzani
- Department of Pharmaceutical Sciences, Università Del Piemonte Orientale, Via Bovio 6, I-28100 Novara, Italy.
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115
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Sensitization Mechanisms of Chronic Itch. INTERNATIONAL JOURNAL OF DERMATOLOGY AND VENEREOLOGY 2019. [DOI: 10.1097/jd9.0000000000000045] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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116
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Li R, Sun H, Zheng H, Zong Z, Li S, Meng T, Li J, Liu Y, Wang C, Li J. Intradermal Injection of Oxytocin Aggravates Chloroquine-Induced Itch Responses via Activating the Vasopressin-1a Receptor/Nitric Oxide Pathway in Mice. Front Pharmacol 2019; 10:1380. [PMID: 31824317 PMCID: PMC6881818 DOI: 10.3389/fphar.2019.01380] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2019] [Accepted: 10/30/2019] [Indexed: 12/14/2022] Open
Abstract
Oxytocin (OT), a hormone synthesized within the paraventricular nucleus and supraoptic nucleus of the hypothalamus, when given intracerebroventricularly, induces strong scratching behaviors. However, it is not clear whether intradermal injection (ID) of OT elicits itch sensation. Herein, we found that OT (0.02 mg/ml) did not elicit an itch-scratching response in mice but aggravated chloroquine (CQ, 3 mmol/L)-elicited scratching behavior. Similar to OT, arginine vasopressin (AVP, 0.02 mg/ml), which is structurally related to OT, also enhanced CQ-induced scratching behavior but did not directly induce scratching behavior in mice. Mechanistically, OT-mediated enhancement of CQ-induced scratching behavior was significantly suppressed by conivaptan (0.05 mg/ml), a vasopressin-1a receptor (V1AR) antagonist and 1,400 W (3 mg/kg), inhibitor of inducible nitric oxide synthase (iNOS), but not OT receptor (OTR) antagonist L-368,899 (0.05 mg/ml). Notably, conivaptan also directly decreased CQ-induced scratching. In conclusion, OT plays a role in CQ-induced scratching behavior via V1AR binding events. V1AR antagonists could be used as possible treatments for CQ-induced itch.
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Affiliation(s)
- Rulong Li
- Department of Physiology, School of Basic Medical Sciences, Shandong University Cheeloo Medical College, Jinan, China
| | - Hua Sun
- Department of the Sixth Internal Medicine, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, China
| | - Haotian Zheng
- Department of Physiology, School of Basic Medical Sciences, Shandong University Cheeloo Medical College, Jinan, China
| | - Zhihua Zong
- Department of Physiology, School of Basic Medical Sciences, Shandong University Cheeloo Medical College, Jinan, China
| | - Shengnan Li
- Department of Physiology, School of Basic Medical Sciences, Shandong University Cheeloo Medical College, Jinan, China
| | - Tingting Meng
- Department of Physiology, School of Basic Medical Sciences, Shandong University Cheeloo Medical College, Jinan, China
| | - Jing Li
- Department of Pathology, Central Hospital of Zibo, Zibo, China
| | - Yunfang Liu
- Center for Strategic Studies, Chinese Academy of Engineering, Beijing, China
| | - Chao Wang
- Department of Rehabilitation Medicine, Shandong Provincial Hospital affiliated to Shandong University, Jinan, China
| | - Jingxin Li
- Department of Physiology, School of Basic Medical Sciences, Shandong University Cheeloo Medical College, Jinan, China
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117
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Kim BH, Lee WJ, Sanjel B, Cho K, Son YK, Park HY, Kim SY, Shim WS. Extracts of the leaves of Pyrus ussuriensis Maxim. Alleviate itch sensation via TSLP-dependent manner in mouse models of atopic dermatitis. Physiol Behav 2019; 210:112624. [PMID: 31325512 DOI: 10.1016/j.physbeh.2019.112624] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Revised: 07/09/2019] [Accepted: 07/16/2019] [Indexed: 10/26/2022]
Abstract
Pyrus ussuriensis Maxim. commonly known as "Sandolbae" in Korean is a pear tree widely distributed across East Asia. Recent studies indicate that P. ussuriensis Maxim. leaves (PUL) have antipruritic effects. This study aimed to determine the effects of PUL extract and its fractions in decreasing the itch sensation and skin lesions in two distinct animal models of atopic dermatitis (AD) induced by dinitrofluorobenzene (DNFB) or house dust mite (HDM). Our results showed that the total ethanol extract of PUL decreased the scratching behavior in mice with DNFB- and HDM-induced AD. Moreover, the ethyl acetate fraction of PUL significantly improved the overall condition of the mice with AD induced by HDM. Further, we used HEK293T cells that express receptors and ion channels for thymic stromal lymphopoietin (TSLP), a potent pruritogen for AD, to determine the mechanisms underlying the antipruritic effects of PUL extract/fractions. Specific subfractions of the PUL strongly inhibited the increase in calcium levels induced by TSLP. In addition, the specific subfraction of PUL inhibited the TSLP-induced increase in calcium levels in cultured mouse dorsal root ganglia neurons. Thus, our results showed that the PUL extract could be effective for alleviating pruritus, and the antipruritic effects were exerted probably via the inhibition of the TSLP pathway in peripheral sensory neurons governing the itch sensation in AD.
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Affiliation(s)
- Bo Hyun Kim
- College of Pharmacy, Gachon University, Hambakmoero 191, Yeonsu-gu, Incheon, Republic of Korea; Gachon Institute of Pharmaceutical Sciences, Hambakmoero 191, Yeonsu-gu, Incheon, Republic of Korea
| | - Wook-Joo Lee
- College of Pharmacy, Gachon University, Hambakmoero 191, Yeonsu-gu, Incheon, Republic of Korea; Gachon Institute of Pharmaceutical Sciences, Hambakmoero 191, Yeonsu-gu, Incheon, Republic of Korea
| | - Babina Sanjel
- College of Pharmacy, Gachon University, Hambakmoero 191, Yeonsu-gu, Incheon, Republic of Korea; Gachon Institute of Pharmaceutical Sciences, Hambakmoero 191, Yeonsu-gu, Incheon, Republic of Korea
| | - Kyohee Cho
- College of Pharmacy, Gachon University, Hambakmoero 191, Yeonsu-gu, Incheon, Republic of Korea; Gachon Institute of Pharmaceutical Sciences, Hambakmoero 191, Yeonsu-gu, Incheon, Republic of Korea
| | - Youn Kyoung Son
- National Institute of Biological Resources, Environmental Research Complex, Incheon, Republic of Korea
| | - Hye Yoon Park
- National Institute of Biological Resources, Environmental Research Complex, Incheon, Republic of Korea
| | - Sun Yeou Kim
- College of Pharmacy, Gachon University, Hambakmoero 191, Yeonsu-gu, Incheon, Republic of Korea; Gachon Institute of Pharmaceutical Sciences, Hambakmoero 191, Yeonsu-gu, Incheon, Republic of Korea
| | - Won-Sik Shim
- College of Pharmacy, Gachon University, Hambakmoero 191, Yeonsu-gu, Incheon, Republic of Korea; Gachon Institute of Pharmaceutical Sciences, Hambakmoero 191, Yeonsu-gu, Incheon, Republic of Korea.
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118
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Siiskonen H, Harvima I. Mast Cells and Sensory Nerves Contribute to Neurogenic Inflammation and Pruritus in Chronic Skin Inflammation. Front Cell Neurosci 2019; 13:422. [PMID: 31619965 PMCID: PMC6759746 DOI: 10.3389/fncel.2019.00422] [Citation(s) in RCA: 94] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Accepted: 09/03/2019] [Indexed: 12/12/2022] Open
Abstract
The intimate interaction between mast cells and sensory nerves can be illustrated by the wheal and surrounding flare in an urticarial reaction in human skin. This reaction is typically associated with an intense itch at the reaction site. Upon activation, cutaneous mast cells release powerful mediators, such as histamine, tryptase, cytokines, and growth factors that can directly stimulate corresponding receptors on itch-mediating sensory nerves. These include, e.g., H1- and H4-receptors, protease-activated receptor-2, IL-31 receptor, and the high-affinity receptor of nerve growth factor (TrkA). On the other hand, sensory nerves can release neuropeptides, including substance P and vasoactive intestinal peptide, that are able to stimulate mast cells to release mediators leading to potentiation of the reciprocal interaction, inflammation, and itch. Even though mast cells are well recognized for their role in allergic skin whealing and urticaria, increasing evidence supports the reciprocal function between mast cells and sensory nerves in neurogenic inflammation in chronic skin diseases, such as psoriasis and atopic dermatitis, which are often characterized by distressing itch, and exacerbated by psychological stress. Increased morphological contacts between mast cells and sensory nerves in the lesional skin in psoriasis and atopic dermatitis as well as experimental models in mice and rats support the essential role for mast cell-sensory nerve communication in consequent pruritus. Therefore, we summarize here the present literature pointing to a close association between mast cells and sensory nerves in pruritic skin diseases as well as review the essential supporting findings on pruritic models in mice and rats.
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Affiliation(s)
- Hanna Siiskonen
- Department of Dermatology, Kuopio University Hospital and University of Eastern Finland, Kuopio, Finland
| | - Ilkka Harvima
- Department of Dermatology, Kuopio University Hospital and University of Eastern Finland, Kuopio, Finland
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119
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Yosipovitch G, Rosen JD, Hashimoto T. Itch: From mechanism to (novel) therapeutic approaches. J Allergy Clin Immunol 2019; 142:1375-1390. [PMID: 30409247 DOI: 10.1016/j.jaci.2018.09.005] [Citation(s) in RCA: 194] [Impact Index Per Article: 38.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Revised: 08/27/2018] [Accepted: 09/07/2018] [Indexed: 12/13/2022]
Abstract
Itch is a common sensory experience that is prevalent in patients with inflammatory skin diseases, as well as in those with systemic and neuropathic conditions. In patients with these conditions, itch is often severe and significantly affects quality of life. Itch is encoded by 2 major neuronal pathways: histaminergic (in acute itch) and nonhistaminergic (in chronic itch). In the majority of cases, crosstalk existing between keratinocytes, the immune system, and nonhistaminergic sensory nerves is responsible for the pathophysiology of chronic itch. This review provides an overview of the current understanding of the molecular, neural, and immune mechanisms of itch: beginning in the skin, proceeding to the spinal cord, and eventually ascending to the brain, where itch is processed. A growing understanding of the mechanisms of chronic itch is expanding, as is our pipeline of more targeted topical and systemic therapies. Our therapeutic armamentarium for treating chronic itch has expanded in the last 5 years, with developments of topical and systemic treatments targeting the neural and immune systems.
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Affiliation(s)
- Gil Yosipovitch
- Department of Dermatology and Cutaneous Surgery and Miami Itch Center Miller School of Medicine University of Miami, Miami, Fla.
| | - Jordan Daniel Rosen
- Department of Dermatology and Cutaneous Surgery and Miami Itch Center Miller School of Medicine University of Miami, Miami, Fla
| | - Takashi Hashimoto
- Department of Dermatology and Cutaneous Surgery and Miami Itch Center Miller School of Medicine University of Miami, Miami, Fla
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120
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Crosson T, Roversi K, Balood M, Othman R, Ahmadi M, Wang JC, Seadi Pereira PJ, Tabatabaei M, Couture R, Eichwald T, Latini A, Prediger RD, Rangachari M, Seehus CR, Foster SL, Talbot S. Profiling of how nociceptor neurons detect danger - new and old foes. J Intern Med 2019; 286:268-289. [PMID: 31282104 DOI: 10.1111/joim.12957] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The host evolves redundant mechanisms to preserve physiological processing and homeostasis. These functions range from sensing internal and external threats, creating a memory of the insult and generating reflexes, which aim to resolve inflammation. Impairment in such functioning leads to chronic inflammatory diseases. By interacting through a common language of ligands and receptors, the immune and sensory nervous systems work in concert to accomplish such protective functions. Whilst this bidirectional communication helps to protect from danger, it can contribute to disease pathophysiology. Thus, the somatosensory nervous system is anatomically positioned within primary and secondary lymphoid tissues and mucosa to modulate immunity directly. Upstream of this interplay, neurons detect danger, which prompts the release of neuropeptides initiating (i) defensive reflexes (ranging from withdrawal response to coughing) and (ii) chemotaxis, adhesion and local infiltration of immune cells. The resulting outcome of such neuro-immune interplay is still ill-defined, but consensual findings start to emerge and support neuropeptides not only as blockers of TH 1-mediated immunity but also as drivers of TH 2 immune responses. However, the modalities detected by nociceptors revealed broader than mechanical pressure and temperature sensing and include signals as various as cytokines and pathogens to immunoglobulins and even microRNAs. Along these lines, we aggregated various dorsal root ganglion sensory neuron expression profiling datasets supporting such wide-ranging sensing capabilities to help identifying new danger detection modalities of these cells. Thus, revealing unexpected aspects of nociceptor neuron biology might prompt the identification of novel drivers of immunity, means to resolve inflammation and strategies to safeguard homeostasis.
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Affiliation(s)
- T Crosson
- From the, Département de Pharmacologie et Physiologie, Faculté de Médecine, Université de Montréal, Montréal, QC, Canada
| | - K Roversi
- From the, Département de Pharmacologie et Physiologie, Faculté de Médecine, Université de Montréal, Montréal, QC, Canada.,Departamento de Farmacologia Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianópolis, Brazil
| | - M Balood
- From the, Département de Pharmacologie et Physiologie, Faculté de Médecine, Université de Montréal, Montréal, QC, Canada.,Axe Neurosciences, Centre de recherche du CHU, Université Laval, Québec, QC, Canada.,Département de Médecine Moléculaire, Faculté de Médecine, Université Laval, Québec, QC, Canada
| | - R Othman
- From the, Département de Pharmacologie et Physiologie, Faculté de Médecine, Université de Montréal, Montréal, QC, Canada
| | - M Ahmadi
- From the, Département de Pharmacologie et Physiologie, Faculté de Médecine, Université de Montréal, Montréal, QC, Canada
| | - J-C Wang
- From the, Département de Pharmacologie et Physiologie, Faculté de Médecine, Université de Montréal, Montréal, QC, Canada.,Graduate Institute of Microbiology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | | | - M Tabatabaei
- From the, Département de Pharmacologie et Physiologie, Faculté de Médecine, Université de Montréal, Montréal, QC, Canada
| | - R Couture
- From the, Département de Pharmacologie et Physiologie, Faculté de Médecine, Université de Montréal, Montréal, QC, Canada
| | - T Eichwald
- Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianópolis, Brazil
| | - A Latini
- Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianópolis, Brazil
| | - R D Prediger
- Departamento de Farmacologia Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianópolis, Brazil
| | - M Rangachari
- Axe Neurosciences, Centre de recherche du CHU, Université Laval, Québec, QC, Canada.,Département de Médecine Moléculaire, Faculté de Médecine, Université Laval, Québec, QC, Canada
| | - C R Seehus
- FM Kirby Neurobiology Center, Children's Hospital, Boston, MA, USA
| | - S L Foster
- Depression Clinical Research Program, Massachusetts General Hospital, Boston, MA, USA
| | - S Talbot
- From the, Département de Pharmacologie et Physiologie, Faculté de Médecine, Université de Montréal, Montréal, QC, Canada
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121
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Ilie MA, Caruntu C, Tampa M, Georgescu SR, Matei C, Negrei C, Ion RM, Constantin C, Neagu M, Boda D. Capsaicin: Physicochemical properties, cutaneous reactions and potential applications in painful and inflammatory conditions. Exp Ther Med 2019; 18:916-925. [PMID: 31384324 PMCID: PMC6639979 DOI: 10.3892/etm.2019.7513] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 09/21/2018] [Indexed: 12/14/2022] Open
Abstract
Capsaicin is a natural protoalkaloid recognized as the main pungent component in hot peppers (Capsicum annuum L.). The capsaicin receptor is highly expressed in the unmyelinated type C nerve fibers originating from small diameter sensory neurons in dorsal root ganglia and cranial nerve ganglia correspondents. Capsaicin and related vanilloids have a variety of effects on primary sensory neurons function, from sensory neuron excitation characterized by local burning sensation and neurogenic inflammation, followed by conduction blockage accompanied by reversible ultrastructural changes of peripheral nociceptive endings (desensitization), going as far as irreversible degenerative changes (neurotoxicity). The main role in capsaicin-induced neurogenic inflammation relies on the capsaicin sensitive, small diameter primary sensory neurons, therefore its evaluation could be used as a diagnostic instrument in functional alterations of cutaneous sensory nerve fibers. Moreover, capsaicin-induced desensitization and neurotoxicity explain the analgesic/anti-nociceptive and anti-inflammatory effects of topical capsaicin and its potential use in the management of painful and inflammatory conditions. In this study, we describe the effects of capsaicin on neurogenic inflammation and nociception, as well as its potential diagnostic value and therapeutic impact in various conditions involving impairment of sensory nerve fibers.
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Affiliation(s)
- Mihaela Adriana Ilie
- Dermatology Research Laboratory, ‘Carol Davila’ University of Medicine and Pharmacy, Bucharest 020021, Romania
- Department of Biochemistry, ‘Carol Davila’ University of Medicine and Pharmacy, Bucharest 020021, Romania
| | - Constantin Caruntu
- Department of Physiology, ‘Carol Davila’ University of Medicine and Pharmacy, Bucharest 020021, Romania
- Department of Dermatology, ‘Prof. N.C. Paulescu’ National Institute of Diabetes, Nutrition and Metabolic Diseases, Bucharest 020475, Romania
| | - Mircea Tampa
- Department of Dermatology, ‘Carol Davila’ University of Medicine and Pharmacy, Bucharest 020021, Romania
| | - Simona-Roxana Georgescu
- Department of Dermatology, ‘Carol Davila’ University of Medicine and Pharmacy, Bucharest 020021, Romania
| | - Clara Matei
- Department of Dermatology, ‘Carol Davila’ University of Medicine and Pharmacy, Bucharest 020021, Romania
| | - Carolina Negrei
- Department of Toxicology, Faculty of Pharmacy, ‘Carol Davila’ University of Medicine and Pharmacy, Bucharest 020956, Romania
| | - Rodica-Mariana Ion
- The National Institute for Research and Development in Chemistry and Petrochemistry - ICECHIM, Bucharest 060021, Romania
| | - Carolina Constantin
- Department of Immunology, ‘Victor Babes’ National Institute of Pathology, Bucharest 050096, Romania
- Department of Pathology, Colentina Clinical Hospital, 020125 Bucharest, Romania
| | - Monica Neagu
- Department of Immunology, ‘Victor Babes’ National Institute of Pathology, Bucharest 050096, Romania
- Department of Pathology, Colentina Clinical Hospital, 020125 Bucharest, Romania
- Department of Biochemistry, Faculty of Biology, University of Bucharest, Bucharest 020125, Romania
| | - Daniel Boda
- Dermatology Research Laboratory, ‘Carol Davila’ University of Medicine and Pharmacy, Bucharest 020021, Romania
- Department of Dermatology, ‘Prof. N.C. Paulescu’ National Institute of Diabetes, Nutrition and Metabolic Diseases, Bucharest 020475, Romania
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122
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BAM8-22 and its receptor MRGPRX1 may attribute to cholestatic pruritus. Sci Rep 2019; 9:10888. [PMID: 31350433 PMCID: PMC6659683 DOI: 10.1038/s41598-019-47267-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Accepted: 07/11/2019] [Indexed: 12/16/2022] Open
Abstract
Pruritus is an unexpected symptom observed in cholestasis and its mechanism is still unclear. Here, we show that bovine adrenal medulla (BAM) 8-22, an endogenous itch-inducing peptide, could be involved in cholestatic pruritus. It was found that bile duct ligation (BDL) mice, an obstructive cholestasis model, showed increased spontaneous scratching behaviour. Importantly, the mRNA level of proenkephalin, a precursor polypeptide of BAM8-22, was significantly increased in the skin of BDL mice. Furthermore, the mRNA level of Mrgprx1, which encodes a receptor for BAM8-22, was significantly increased in the dorsal root ganglia (DRG) of BDL mice. This was further confirmed by elevation of intracellular calcium levels upon BAM8-22 treatment in primarily-cultured DRG neurons. In addition, BDL mice showed augmented scratching behaviour by BAM8-22, indicating enhanced activity of MRGPRX1. Moreover, the skin homogenate of BDL mice induced elevation of intracellular calcium levels through MRGPRX1. Finally, among the various bile acids, chenodeoxycholic acid significantly increased proenkephalin transcription in a human keratinocyte cell line (HaCaT). In conclusion, cholestatic pruritus could be attributed in part to enhanced action of both BAM8-22 in the skin and its receptor MRGPRX1 in sensory neurons.
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123
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Dong X, Dong X. Peripheral and Central Mechanisms of Itch. Neuron 2019; 98:482-494. [PMID: 29723501 DOI: 10.1016/j.neuron.2018.03.023] [Citation(s) in RCA: 230] [Impact Index Per Article: 46.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Revised: 03/12/2018] [Accepted: 03/15/2018] [Indexed: 12/15/2022]
Abstract
Itch is a unique sensory experience that is encoded by genetically distinguishable neurons both in the peripheral nervous system (PNS) and central nervous system (CNS) to elicit a characteristic behavioral response (scratching). Itch interacts with the other sensory modalities at multiple locations, from its initiation in a particular dermatome to its transmission to the brain where it is finally perceived. In this review, we summarize the current understanding of the molecular and neural mechanisms of itch by starting in the periphery, where itch is initiated, and discussing the circuits involved in itch processing in the CNS.
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Affiliation(s)
- Xintong Dong
- The Solomon H. Snyder Department of Neuroscience and the 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.
| | - Xinzhong Dong
- The Solomon H. Snyder Department of Neuroscience and the 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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Hawro T, Lehmann S, Deuring E, Weller K, Altrichter S, Church M, Maurer M, Metz M. Comparison of pruritus and sensory qualities induced by capsaicin, histamine and cowhage. J Eur Acad Dermatol Venereol 2019; 33:1755-1761. [DOI: 10.1111/jdv.15743] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Accepted: 05/29/2019] [Indexed: 11/29/2022]
Affiliation(s)
- T. Hawro
- Department of Dermatology and Allergy Charité – Universitätsmedizin Berlin Berlin Germany
| | - S. Lehmann
- Department of Dermatology and Allergy Charité – Universitätsmedizin Berlin Berlin Germany
| | - E. Deuring
- Department of Dermatology and Allergy Charité – Universitätsmedizin Berlin Berlin Germany
| | - K. Weller
- Department of Dermatology and Allergy Charité – Universitätsmedizin Berlin Berlin Germany
| | - S. Altrichter
- Department of Dermatology and Allergy Charité – Universitätsmedizin Berlin Berlin Germany
| | - M.K. Church
- Department of Dermatology and Allergy Charité – Universitätsmedizin Berlin Berlin Germany
| | - M. Maurer
- Department of Dermatology and Allergy Charité – Universitätsmedizin Berlin Berlin Germany
| | - M. Metz
- Department of Dermatology and Allergy Charité – Universitätsmedizin Berlin Berlin Germany
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Signs of chronic itch in the mouse imiquimod model of psoriasiform dermatitis: sex differences and roles of TRPV1 and TRPA1. ACTA ACUST UNITED AC 2019; 4. [PMID: 34164579 PMCID: PMC8219242 DOI: 10.1097/itx.0000000000000025] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Plaque psoriasis is a chronic inflammatory skin disease that affects a substantial proportion of the world population. This disorder is characterized by scaly, thick skin, intense ongoing itch, and itch from light touch (such as clothing contacting skin, called “alloknesis”). Imiquimod is a topical treatment for basal cell carcinomas and warts that has been used to create a mouse model of plaque psoriasis. Imiquimod-treated male, but not female, wildtype B6 mice showed significant increases in spontaneous scratching, while both sexes exhibited increased alloknesis, indicative of chronic itch. TRPV1 and TRPA1 knockout (KO) mice all exhibited numeric increases in spontaneous scratching which were significant for TRPV1KO mice and TRPA1KO males. Female TRPV1KO and TRPA1KO mice exhibited imiquimod-induced increases in alloknesis scores that did not significantly differ from wildtypes, while alloknesis scores in imiquimod-treated male TRPV1KO and TRPA1KO mice were significantly lower compared with wildtypes, suggesting that these ion channels are necessary for the development of alloknesis in males but not females in this model. Curiously, none of the groups exhibited any significant overall change in chloroquine-evoked scratching following imiquimod treatment, indicating that hyperknesis does not develop in this mouse model. Overall, the data indicate that there are sex differences in this mouse model of psoriasis, and that TRPV1 and TRPA1 ion channels have a small role in promoting the development of itch sensitization. This contrasts with the far greater role these channels play in the manifestation of skin changes in psoriatic dermatitis.
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Nociceptor Signalling through ion Channel Regulation via GPCRs. Int J Mol Sci 2019; 20:ijms20102488. [PMID: 31137507 PMCID: PMC6566991 DOI: 10.3390/ijms20102488] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 05/08/2019] [Accepted: 05/13/2019] [Indexed: 12/23/2022] Open
Abstract
The prime task of nociceptors is the transformation of noxious stimuli into action potentials that are propagated along the neurites of nociceptive neurons from the periphery to the spinal cord. This function of nociceptors relies on the coordinated operation of a variety of ion channels. In this review, we summarize how members of nine different families of ion channels expressed in sensory neurons contribute to nociception. Furthermore, data on 35 different types of G protein coupled receptors are presented, activation of which controls the gating of the aforementioned ion channels. These receptors are not only targeted by more than 20 separate endogenous modulators, but can also be affected by pharmacotherapeutic agents. Thereby, this review provides information on how ion channel modulation via G protein coupled receptors in nociceptors can be exploited to provide improved analgesic therapy.
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127
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Banovic F, Denley T, Blubaugh A. Dose-dependent pruritogenic and inflammatory effects of intradermal injections of histamine, compound 48/80 and anti-canine IgE in healthy dogs. Vet Dermatol 2019; 30:325-e91. [PMID: 31038263 DOI: 10.1111/vde.12754] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/26/2019] [Indexed: 11/28/2022]
Abstract
BACKGROUND Scratching behaviours associated with intradermal (i.d.) injection of pruritogens such as histamine and compound 48/80 into the skin of mice and humans is the commonly used model to advance itch research and drug development. The predictive validity of this model is poorly documented in dogs. OBJECTIVES To evaluate the dose-dependent effects of pruritogenic substances, each with a different mechanism of action, in healthy dogs. ANIMALS Ten healthy laboratory beagles. METHODS AND MATERIALS All dogs were video-recorded for 30 min post-injection (mpi) of i.d. goat anti-canine IgE (4 and 25 μg/site), histamine and compound 48/80 (50, 100, 200, 400 μg/site); two buffered saline injections served as controls. Two blinded investigators reviewed the pruritic behaviours of all video recordings. Global wheal scores were evaluated at 30 min by a blinded investigator. RESULTS All dogs showed wheal and erythema at the pruritogen injection site; global wheal scores at 30 min of each substance significantly increased at all concentrations compared to control (P ≤ 0.05). A blinded evaluation revealed that all pruritogens induced mild acute pruritic behaviours at the site of injection. There was no injection site pain seen in any dog. Compared to controls, injections of pruritogens did not significantly affect the pruritic seconds or occurrence of pruritic episodes for any of the substances. CONCLUSIONS AND CLINICAL SIGNIFICANCE These preliminary results suggest that i.d. injections of the studied pruritogens can induce cutaneous wheal and flare response in healthy dogs; but inconsistencies occur in the induction of itch, even with the different concentrations of pruritogens.
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Affiliation(s)
- Frane Banovic
- Department of Small Animal Medicine and Surgery, College of Veterinary Medicine, University of Georgia, 2200 College Station Road, Athens, GA, 30602, USA
| | - Tara Denley
- Department of Small Animal Medicine and Surgery, College of Veterinary Medicine, University of Georgia, 2200 College Station Road, Athens, GA, 30602, USA
| | - Amanda Blubaugh
- Department of Small Animal Medicine and Surgery, College of Veterinary Medicine, University of Georgia, 2200 College Station Road, Athens, GA, 30602, USA
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Kim YW, Zhou T, Ko EA, Kim S, Lee D, Seo Y, Kwon N, Choi T, Lim H, Cho S, Bae G, Hwang Y, Kim D, Park H, Lee M, Jang E, Choi J, Bae H, Lim I, Bang H, Ko JH. Prediction of itching diagnostic marker through RNA sequencing of contact hypersensitivity and skin scratching stimulation mice models. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2019; 23:151-159. [PMID: 30820159 PMCID: PMC6384194 DOI: 10.4196/kjpp.2019.23.2.151] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/31/2018] [Revised: 01/04/2019] [Accepted: 01/10/2019] [Indexed: 01/28/2023]
Abstract
Pruritus (itching) is classically defined as an unpleasant cutaneous sensation that leads to scratching behavior. Although the scientific criteria of classification for pruritic diseases are not clear, it can be divided as acute or chronic by duration of symptoms. In this study, we investigated whether skin injury caused by chemical (contact hypersensitivity, CHS) or physical (skin-scratching stimulation, SSS) stimuli causes initial pruritus and analyzed gene expression profiles systemically to determine how changes in skin gene expression in the affected area are related to itching. In both CHS and SSS, we ranked the Gene Ontology Biological Process terms that are generally associated with changes. The factors associated with upregulation were keratinization, inflammatory response and neutrophil chemotaxis. The Kyoto Encyclopedia of Genes and Genomes pathway shows the difference of immune system, cell growth and death, signaling molecules and interactions, and signal transduction pathways. Il1a , Il1b and Il22 were upregulated in the CHS, and Tnf, Tnfrsf1b, Il1b, Il1r1 and Il6 were upregulated in the SSS. Trpc1 channel genes were observed in representative itching-related candidate genes. By comparing and analyzing RNA-sequencing data obtained from the skin tissue of each animal model in these characteristic stages, it is possible to find useful diagnostic markers for the treatment of itching, to diagnose itching causes and to apply customized treatment.
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Affiliation(s)
- Young-Won Kim
- Department of Physiology, Chung-Ang University College of Medicine, Seoul 06974, Korea
| | - Tong Zhou
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV 89557, USA
| | - Eun-A Ko
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV 89557, USA
| | - Seongtae Kim
- Department of Physiology, Chung-Ang University College of Medicine, Seoul 06974, Korea
| | - Donghee Lee
- Department of Physiology, Chung-Ang University College of Medicine, Seoul 06974, Korea
| | - Yelim Seo
- Department of Physiology, Chung-Ang University College of Medicine, Seoul 06974, Korea
| | - Nahee Kwon
- Department of Medicine, Chung-Ang University College of Medicine, Seoul 06974, Korea
| | - Taeyeon Choi
- Department of Medicine, Chung-Ang University College of Medicine, Seoul 06974, Korea
| | - Heejung Lim
- Department of Medicine, Chung-Ang University College of Medicine, Seoul 06974, Korea
| | - Sungvin Cho
- Department of Medicine, Chung-Ang University College of Medicine, Seoul 06974, Korea
| | - Gwanhui Bae
- Department of Medicine, Chung-Ang University College of Medicine, Seoul 06974, Korea
| | - Yuseong Hwang
- Department of Medicine, Chung-Ang University College of Medicine, Seoul 06974, Korea
| | - Dojin Kim
- Department of Medicine, Chung-Ang University College of Medicine, Seoul 06974, Korea
| | - Hyewon Park
- Department of Medicine, Chung-Ang University College of Medicine, Seoul 06974, Korea
| | - Minjae Lee
- Department of Medicine, Chung-Ang University College of Medicine, Seoul 06974, Korea
| | - Eunkyung Jang
- Department of Medicine, Chung-Ang University College of Medicine, Seoul 06974, Korea
| | - Jeongyoon Choi
- Department of Physiology, Chung-Ang University College of Medicine, Seoul 06974, Korea
| | - Hyemi Bae
- Department of Physiology, Chung-Ang University College of Medicine, Seoul 06974, Korea
| | - Inja Lim
- Department of Physiology, Chung-Ang University College of Medicine, Seoul 06974, Korea
| | - Hyoweon Bang
- Department of Physiology, Chung-Ang University College of Medicine, Seoul 06974, Korea
| | - Jae-Hong Ko
- Department of Physiology, Chung-Ang University College of Medicine, Seoul 06974, Korea
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129
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Xie B, Li X. Inflammatory mediators causing cutaneous chronic itch in some diseases via transient receptor potential channel subfamily V member 1 and subfamily A member 1. J Dermatol 2019; 46:177-185. [PMID: 30588658 PMCID: PMC6590237 DOI: 10.1111/1346-8138.14749] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Accepted: 11/19/2018] [Indexed: 12/23/2022]
Abstract
Chronic itch with an itch-scratch vicious circle is a significant problem in a large amount of diseases. Some of these diseases, such as psoriasis, atopic dermatitis, prurigo nodularis, Sézary syndrome, uremic pruritus, diabetes and jaundice, are common. For a very long time, chronic itch has been a thorny problem with few effective treatments. Because of this, itch researchers and dermatologists seek to find the mechanisms among chronic itch, inflammatory cytokines and neurons. As an immediate area of research focus, we are going to find the peripheral cross-talk between neurons and skin cells. Two receptors, named transient receptor potential channel vanilloid 1 and transient receptor potential channel ankyrin transmembrane protein 1, have been shown to play important roles in chronic itch. Many advances have been made so far this decade. This review talks about the updated mechanism of itch-related inflammatory cytokines via transient receptor potential channels in cutaneous chronic itch and corresponding diseases. The search for itch-related inflammatory mediators and the structure of transient receptor potential channels this decade could deepen our understanding of the mechanism of itch and help us find more treatments of chronic itch in the future.
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Affiliation(s)
- Bo Xie
- Department of PharmacologyInstitute of DermatologyChinese Academy of Medical Sciences and Peking Union Medical CollegeNanjingChina
| | - Xin‐Yu Li
- Department of PharmacologyInstitute of DermatologyChinese Academy of Medical Sciences and Peking Union Medical CollegeNanjingChina
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130
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Yu S, Li Y, Zhou Y, Follansbee T, Hwang ST. Immune mediators and therapies for pruritus in atopic dermatitis and psoriasis. JOURNAL OF CUTANEOUS IMMUNOLOGY AND ALLERGY 2019. [DOI: 10.1002/cia2.12049] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Affiliation(s)
- Sebastian Yu
- Department of Dermatology; University of California Davis School of Medicine; Sacramento California
- Department of Dermatology; Kaohsiung Medical University Hospital; Kaohsiung Medical University; Kaohsiung Taiwan
- Department of Dermatology; College of Medicine; Kaohsiung Medical University; Kaohsiung Taiwan
| | - Yanxi Li
- Department of Dermatology; University of California Davis School of Medicine; Sacramento California
| | - Yan Zhou
- Department of Dermatology; University of California Davis School of Medicine; Sacramento California
| | - Taylor Follansbee
- Department of Neurobiology, Physiology and Behavior; University of California Davis; Davis California
| | - Samuel T. Hwang
- Department of Dermatology; University of California Davis School of Medicine; Sacramento California
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131
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Riccio D, Andersen HH, Arendt-Nielsen L. Antipruritic effects of transient heat stimulation on histaminergic and nonhistaminergic itch. Br J Dermatol 2019; 181:786-795. [PMID: 30802929 DOI: 10.1111/bjd.17825] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/11/2019] [Indexed: 01/21/2023]
Abstract
BACKGROUND Chronic itch is notoriously difficult to treat. Counterstimuli are able to inhibit itch, but this principle is difficult to apply in clinical practice, and the mechanisms behind counterstimulation-induced itch suppression in humans are unclear. OBJECTIVES Firstly, to analyse the stimulus-response effects of transient heat stimuli on histaminergic and nonhistaminergic itch, and secondly, to investigate whether the antipruritic effect depends on homotopic (peripheral mediation) or heterotopic (central mediation) counterstimulation relative to the itch provocation site. METHODS Eighteen healthy volunteers participated (eight female, mean age 25·7 ± 0·8 years). Itch was evoked on premarked areas of the volar forearms, by either histamine (1% solution) or cowhage (35-40 spicules). In addition to the itch provocations (experiment 1), 5-s homotopic heat stimuli at 32, 40, 45 or 50 °C were applied. In experiment 2, heat stimuli were applied either homotopically, intrasegmentally (next to the provocation site) or extrasegmentally (dorsal forearm). Itch intensity was evaluated throughout the procedures using a digital visual analogue scale. RESULTS Homotopic counterstimuli inhibited histaminergic itch by 41·3% at 45 °C (P < 0·01) and by 76·7% at 50 °C (P < 0·001). Cowhage-induced itch was less prone to counterstimulation and was significantly diminished only at 50 °C, by 43·6% (P = 0·009). Counterstimulations applied heterotopically were not able to inhibit itch significantly. CONCLUSIONS Itch pathway-specific effects of counterstimuli were observed between homo- and heterotopic stimulation. Histaminergic itch was robustly inhibited by short-term homotopic noxious heat stimuli for up to 10 min. Nonhistaminergic itch was only weakly inhibited. The inhibitory effects exerted by the short-term heat stimuli only occurred following homotopic counterstimulation.
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Affiliation(s)
- D Riccio
- Center for Neuroplasticity and Pain (CNAP), Aalborg University, Aalborg, Denmark.,Laboratory for Experimental Cutaneous Pain and Itch Research, SMI, Department of Health Science and Technology, Faculty of Medicine, Aalborg University, Aalborg, Denmark
| | - H H Andersen
- Laboratory for Experimental Cutaneous Pain and Itch Research, SMI, Department of Health Science and Technology, Faculty of Medicine, Aalborg University, Aalborg, Denmark
| | - L Arendt-Nielsen
- Center for Neuroplasticity and Pain (CNAP), Aalborg University, Aalborg, Denmark.,Laboratory for Experimental Cutaneous Pain and Itch Research, SMI, Department of Health Science and Technology, Faculty of Medicine, Aalborg University, Aalborg, Denmark
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132
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Rajchgot T, Thomas SC, Wang JC, Ahmadi M, Balood M, Crosson T, Dias JP, Couture R, Claing A, Talbot S. Neurons and Microglia; A Sickly-Sweet Duo in Diabetic Pain Neuropathy. Front Neurosci 2019; 13:25. [PMID: 30766472 PMCID: PMC6365454 DOI: 10.3389/fnins.2019.00025] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2018] [Accepted: 01/11/2019] [Indexed: 12/11/2022] Open
Abstract
Diabetes is a common condition characterized by persistent hyperglycemia. High blood sugar primarily affects cells that have a limited capacity to regulate their glucose intake. These cells include capillary endothelial cells in the retina, mesangial cells in the renal glomerulus, Schwann cells, and neurons of the peripheral and central nervous systems. As a result, hyperglycemia leads to largely intractable complications such as retinopathy, nephropathy, hypertension, and neuropathy. Diabetic pain neuropathy is a complex and multifactorial disease that has been associated with poor glycemic control, longer diabetes duration, hypertension, advanced age, smoking status, hypoinsulinemia, and dyslipidemia. While many of the driving factors involved in diabetic pain are still being investigated, they can be broadly classified as either neuron -intrinsic or -extrinsic. In neurons, hyperglycemia impairs the polyol pathway, leading to an overproduction of reactive oxygen species and reactive nitrogen species, an enhanced formation of advanced glycation end products, and a disruption in Na+/K+ ATPase pump function. In terms of the extrinsic pathway, hyperglycemia leads to the generation of both overactive microglia and microangiopathy. The former incites a feed-forward inflammatory loop that hypersensitizes nociceptor neurons, as observed at the onset of diabetic pain neuropathy. The latter reduces neurons' access to oxygen, glucose and nutrients, prompting reductions in nociceptor terminal expression and losses in sensation, as observed in the later stages of diabetic pain neuropathy. Overall, microglia can be seen as potent and long-lasting amplifiers of nociceptor neuron activity, and may therefore constitute a potential therapeutic target in the treatment of diabetic pain neuropathy.
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Affiliation(s)
- Trevor Rajchgot
- Département de Pharmacologie et Physiologie, Faculté de Médecine, Université de Montréal, Montréal, QC, Canada
| | - Sini Christine Thomas
- Département de Pharmacologie et Physiologie, Faculté de Médecine, Université de Montréal, Montréal, QC, Canada
| | - Jo-Chiao Wang
- Graduate Institute of Microbiology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Maryam Ahmadi
- Département de Pharmacologie et Physiologie, Faculté de Médecine, Université de Montréal, Montréal, QC, Canada
| | - Mohammad Balood
- Département de Pharmacologie et Physiologie, Faculté de Médecine, Université de Montréal, Montréal, QC, Canada
| | - Théo Crosson
- Département de Pharmacologie et Physiologie, Faculté de Médecine, Université de Montréal, Montréal, QC, Canada
| | - Jenny Pena Dias
- Johns Hopkins University School of Medicine, Division of Endocrinology, Diabetes and Metabolism, Baltimore, MD, United States
| | - Réjean Couture
- Département de Pharmacologie et Physiologie, Faculté de Médecine, Université de Montréal, Montréal, QC, Canada
| | - Audrey Claing
- Département de Pharmacologie et Physiologie, Faculté de Médecine, Université de Montréal, Montréal, QC, Canada
| | - Sébastien Talbot
- Département de Pharmacologie et Physiologie, Faculté de Médecine, Université de Montréal, Montréal, QC, Canada
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133
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Lee YW, Won CH, Jung K, Nam HJ, Choi G, Park YH, Park M, Kim B. Efficacy and safety of PAC-14028 cream - a novel, topical, nonsteroidal, selective TRPV1 antagonist in patients with mild-to-moderate atopic dermatitis: a phase IIb randomized trial. Br J Dermatol 2019; 180:1030-1038. [PMID: 30623408 PMCID: PMC6850419 DOI: 10.1111/bjd.17455] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/26/2018] [Indexed: 12/21/2022]
Abstract
Background Transient receptor potential vanilloid subfamily, member 1 (TRPV1) may play an important role in pruritus and inflammation induction in atopic dermatitis (AD). The treatment effect of TRPV1 antagonist via topical application in patients with AD remains unknown. Objectives To assess the clinical efficacy and safety of PAC‐14028, a TRPV1 antagonist, via topical application in patients with AD. Methods In this 8‐week, phase IIb, randomized, double‐blind, multicentre, vehicle‐controlled study, patients with mild‐to‐moderate AD were randomized to receive PAC‐14028 cream 0·1%, 0·3%, 1·0% or vehicle cream twice daily. The primary efficacy end point was the Investigator's Global Assessment (IGA) success rate defined as the percentage of patients with an IGA score of 0 or 1 at week 8. The secondary efficacy end points included the severity Scoring of Atopic Dermatitis (SCORAD) index and Eczema Area and Severity Index (EASI) 75/90. Results A total of 194 patients were enrolled. IGA success rates at week 8 were 14·58% for vehicle cream, 42·55% for PAC‐14028 cream 0·1% (P = 0·0025 vs. vehicle), 38·30% for PAC‐14028 cream 0·3% (P = 0·0087 vs. vehicle) and 57·45% for PAC‐14028 cream 1·0% (P < 0·001 vs. vehicle). In particular, statistically significant differences were found between the vehicle and treatment groups in the IGA success rates with two‐grade improvement. The SCORAD index, EASI 75/90, sleep disturbance score and pruritus visual analogue scale showed a trend towards improvement. No significant safety issues were reported. Conclusions PAC‐14028 cream may be an effective and safe treatment modality for the treatment of patients with mild‐to‐moderate AD. What is already known about this topic? Atopic dermatitis (AD) is one of the most common inflammatory skin diseases characterized by pruritic erythematous skin lesions and barrier dysfunction. Transient receptor potential vanilloid subfamily, member 1 (TRPV1) antagonists suppress the release of pruritic and proinflammatory mediators. The preclinical results demonstrate the feasibility of TRPV1 as a potential therapeutic target for the treatment of AD.
What does this study add? TRPV1 regulates inflammation and pruritus in patients with AD. PAC‐14028 cream, a novel TRPV1 antagonist, was superior to vehicle in improving clinical symptoms and signs with a favourable safety profile in adults with mild‐to‐moderate AD. TRPV1 antagonism may play a role as a promising nonsteroidal topical treatment target for AD with a new mechanism of action.
Linked Editorial:https://doi.org/10.1111/bjd.17777. https://doi.org/10.1111/bjd.17802 available online https://www.bjdonline.com/article/
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Affiliation(s)
- Y W Lee
- Department of Dermatology, Konkuk University School of Medicine, Seoul, Republic of Korea
| | - C-H Won
- Department of Dermatology, Ulsan University College of Medicine, Asan Medical Center, Seoul, Republic of Korea
| | - K Jung
- Vital Beautie Research Institute, AmorePacific Corporation R&D Center, Yongin, Republic of Korea
| | - H-J Nam
- Vital Beautie Research Institute, AmorePacific Corporation R&D Center, Yongin, Republic of Korea
| | - G Choi
- Vital Beautie Research Institute, AmorePacific Corporation R&D Center, Yongin, Republic of Korea
| | - Y-H Park
- Vital Beautie Research Institute, AmorePacific Corporation R&D Center, Yongin, Republic of Korea
| | - M Park
- Vital Beautie Research Institute, AmorePacific Corporation R&D Center, Yongin, Republic of Korea
| | - B Kim
- Department of Dermatology, Chung-Ang University College of Medicine, Seoul, Republic of Korea
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134
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Emrick JJ, Mathur A, Wei J, Gracheva EO, Gronert K, Rosenblum MD, Julius D. Tissue-specific contributions of Tmem79 to atopic dermatitis and mast cell-mediated histaminergic itch. Proc Natl Acad Sci U S A 2018; 115:E12091-E12100. [PMID: 30463955 PMCID: PMC6305010 DOI: 10.1073/pnas.1814132115] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Atopic dermatitis (AD) is the most common skin disease in children. It is characterized by relapsing inflammation, skin-barrier defects, and intractable itch. However, the pathophysiology of itch in AD remains enigmatic. Here, we examine the contribution of Tmem79, an orphan transmembrane protein linked to AD in both mice and humans. We show that Tmem79 is expressed by both keratinocytes and sensory neurons, but that loss of keratinocytic Tmem79 is sufficient to elicit robust scratching. Tmem79-/- mice demonstrate an accumulation of dermal mast cells, which are diminished following chronic treatment with cyclooxygenase inhibitors and an EP3 receptor antagonist. In Tmem79-/- mice, mast cell degranulation produces histaminergic itch in a histamine receptor 1/histamine receptor 4 (H4R/H1R)-dependent manner that may involve activation of TRPV1- afferents. TMEM79 has limited sequence homology to a family of microsomal glutathione transferases and confers protection from cellular accumulation of damaging reactive species, and may thus play a role in regulating oxidative stress. In any case, mechanistic insights from this model suggest that therapeutics targeting PGE2 and/or H1R/H4R histaminergic signaling pathways may represent useful avenues to treat Tmem79-associated AD itch. Our findings suggest that individuals with mutations in Tmem79 develop AD due to the loss of protection from oxidative stress.
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Affiliation(s)
- Joshua J Emrick
- Department of Physiology, University of California, San Francisco, CA 94143
- School of Dentistry, University of California, San Francisco, CA 94143
| | - Anubhav Mathur
- Department of Dermatology, University of California, San Francisco, CA 94143
| | - Jessica Wei
- Vision Science Graduate Program, School of Optometry, University of California, Berkeley, CA 94720
| | - Elena O Gracheva
- Department of Physiology, University of California, San Francisco, CA 94143
| | - Karsten Gronert
- Vision Science Graduate Program, School of Optometry, University of California, Berkeley, CA 94720
| | - Michael D Rosenblum
- Department of Dermatology, University of California, San Francisco, CA 94143
| | - David Julius
- Department of Physiology, University of California, San Francisco, CA 94143;
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135
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Min H, Cho WH, Lee H, Choi B, Kim YJ, Lee HK, Joo Y, Jung SJ, Choi SY, Lee S, Lee SJ. Association of TRPV1 and TLR4 through the TIR domain potentiates TRPV1 activity by blocking activation-induced desensitization. Mol Pain 2018; 14:1744806918812636. [PMID: 30355052 PMCID: PMC6856976 DOI: 10.1177/1744806918812636] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Background We have previously reported that histamine-induced pruritus was attenuated in
toll-like receptor 4 (TLR4) knockout mice due to decreased transient
receptor potential V1 (TRPV1) sensitivity. Our results implied that TLR4
potentiated TRPV1 activation in sensory neurons; however, the molecular
mechanism has yet to be elucidated. In this study, we investigated the
molecular mechanisms of TLR4-mediated TRPV1 potentiation using
TLR4-deficient sensory neurons and a heterologous expression system. Methods Primary sensory neurons were obtained from wild-type or TLR4 knockout mice,
and HEK293T cells expressing TRPV1 and TLR4 were prepared by transient
transfection. TRPV1 activity was analyzed by calcium imaging,
fluorophotometry, and patch-clamp recording. Subcellular protein
distribution was tested by immunocytochemistry and cell surface
biotinylation assay. Protein interaction was assessed by western blot and
immunoprecipitation assay. Results Direct association between TRPV1 and TLR4 was detected in HEK293T cells upon
heterologous TRPV1 and TLR4 expression. In an immunoprecipitation assay
using TLR4-deletion mutants and soluble toll/interleukin-1 receptor (TIR)
protein, the cytoplasmic TIR domain of TLR4 was required for TLR4-TRPV1
association and TRPV1 potentiation. In TLR4-deficient sensory neurons, the
activation-induced desensitization of TRPV1 increased, accompanied by
enhanced TRPV1 clearance from the cell membrane upon activation compared to
wild-type neurons. In addition, heterologous TLR4 expression inhibited
activation-induced TRPV1 endocytosis and lysosomal degradation in HEK293T
cells. Conclusion Our data show that direct association between TRPV1 and TLR4 through the TIR
domain enhances TRPV1 activity by blocking activation-induced TRPV1
desensitization.
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Affiliation(s)
- Hyunjung Min
- 1 Department of Neuroscience and Physiology, Dental Research Institute, School of Dentistry, Seoul National University, Republic of Korea
| | - Woo-Hyun Cho
- 1 Department of Neuroscience and Physiology, Dental Research Institute, School of Dentistry, Seoul National University, Republic of Korea
| | - Hyunkyoung Lee
- 1 Department of Neuroscience and Physiology, Dental Research Institute, School of Dentistry, Seoul National University, Republic of Korea
| | - Boomin Choi
- 1 Department of Neuroscience and Physiology, Dental Research Institute, School of Dentistry, Seoul National University, Republic of Korea
| | - Yoon-Jung Kim
- 1 Department of Neuroscience and Physiology, Dental Research Institute, School of Dentistry, Seoul National University, Republic of Korea
| | - Han Kyu Lee
- 2 Department of Biomedical Science, Graduate School of Biomedical Science and Engineering, Hanyang University, Seoul, South Korea
| | - Yeonhee Joo
- 3 Department of Microbiology, School of Systems Biology, Chungnam National University, Daejeon, Republic of Korea
| | - Sung Jun Jung
- 2 Department of Biomedical Science, Graduate School of Biomedical Science and Engineering, Hanyang University, Seoul, South Korea
| | - Se-Young Choi
- 1 Department of Neuroscience and Physiology, Dental Research Institute, School of Dentistry, Seoul National University, Republic of Korea
| | - Soojin Lee
- 3 Department of Microbiology, School of Systems Biology, Chungnam National University, Daejeon, Republic of Korea
| | - Sung Joong Lee
- 1 Department of Neuroscience and Physiology, Dental Research Institute, School of Dentistry, Seoul National University, Republic of Korea
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136
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TRP Channels as Drug Targets to Relieve Itch. Pharmaceuticals (Basel) 2018; 11:ph11040100. [PMID: 30301231 PMCID: PMC6316386 DOI: 10.3390/ph11040100] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 09/26/2018] [Accepted: 10/03/2018] [Indexed: 12/14/2022] Open
Abstract
Although acute itch has a protective role by removing irritants to avoid further damage, chronic itch is debilitating, significantly impacting quality of life. Over the past two decades, a considerable amount of stimulating research has been carried out to delineate mechanisms of itch at the molecular, cellular, and circuit levels. There is growing evidence that transient receptor potential (TRP) channels play important roles in itch signaling. The purpose of this review is to summarize our current knowledge about the role of TRP channels in the generation of itch under both physiological and pathological conditions, thereby identifying them as potential drug targets for effective anti-itch therapies.
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137
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Lee HK, Park SB, Chang SY, Jung SJ. Antipruritic effect of curcumin on histamine-induced itching in mice. THE KOREAN JOURNAL OF PHYSIOLOGY & PHARMACOLOGY : OFFICIAL JOURNAL OF THE KOREAN PHYSIOLOGICAL SOCIETY AND THE KOREAN SOCIETY OF PHARMACOLOGY 2018; 22:547-554. [PMID: 30181701 PMCID: PMC6115343 DOI: 10.4196/kjpp.2018.22.5.547] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Revised: 06/01/2018] [Accepted: 06/07/2018] [Indexed: 11/29/2022]
Abstract
Itching is a common clinical symptom of skin disease that significantly affects a patient's quality of life. Transient receptor potential vanilloid 1 (TRPV1) receptors of keratinocytes and peripheral nerve fibers in skin are involved in the regulation of itching as well as pain. In this study, we investigated whether curcumin, which acts on TRPV1 receptors, affects histamine-induced itching in mice, using behavioral tests and electrophysiological approaches. We found that histamine-induced itching was blocked by topical application of curcumin in a concentration-dependent manner. In ex-vivo recordings, histamine-induced discharges of peripheral nerves were reduced by the application of curcumin, indicating that curcumin acts directly on peripheral nerves. Additionally, curcumin blocked the histamine-induced inward current via activation of TRPV1 (curcumin IC50=523 nM). However, it did not alter chloroquine-induced itching behavior in mice, which is associated with transient receptor potential ankyrin 1 (TRPA1). Taken together, our results suggest that histamine-induced itching can be blocked by topical application of curcumin through the inhibitory action of curcumin on TRPV1 receptors in peripheral nerves.
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Affiliation(s)
- Han Kyu Lee
- Department of Biomedical Science, Graduate School of Biomedical Science and Engineering, Hanyang University, Seoul 04763, Korea
| | - Seok Bum Park
- Department of Physiology, College of Medicine, Kangwon National University, Chuncheon 24341, Korea
| | - Su-youne Chang
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN 55902, USA
| | - Sung Jun Jung
- Department of Biomedical Science, Graduate School of Biomedical Science and Engineering, Hanyang University, Seoul 04763, Korea
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138
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The endocannabinoid system of the skin. A potential approach for the treatment of skin disorders. Biochem Pharmacol 2018; 157:122-133. [PMID: 30138623 DOI: 10.1016/j.bcp.2018.08.022] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Accepted: 08/16/2018] [Indexed: 12/31/2022]
Abstract
The skin is the largest organ of the body and has a complex and very active structure that contributes to homeostasis and provides the first line defense against injury and infection. In the past few years it has become evident that the endocannabinoid system (ECS) plays a relevant role in healthy and diseased skin. Specifically, we review how the dysregulation of ECS has been associated to dermatological disorders such as atopic dermatitis, psoriasis, scleroderma and skin cancer. Therefore, the druggability of the ECS could open new research avenues for the treatment of the pathologies mentioned. Numerous studies have reported that phytocannabinoids and their biological analogues modulate a complex network pharmacology involved in the modulation of ECS, focusing on classical cannabinoid receptors, transient receptor potential channels (TRPs), and peroxisome proliferator-activated receptors (PPARs). The combined targeting of several end-points seems critical to provide better chances of therapeutically success, in sharp contrast to the one-disease-one-target dogma that permeates current drug discovery campaigns.
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139
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Sun XY, Sun LL, Qi H, Gao Q, Wang GX, Wei NN, Wang K. Antipruritic Effect of Natural Coumarin Osthole through Selective Inhibition of Thermosensitive TRPV3 Channel in the Skin. Mol Pharmacol 2018; 94:1164-1173. [PMID: 30108138 DOI: 10.1124/mol.118.112466] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Accepted: 07/16/2018] [Indexed: 12/14/2022] Open
Abstract
Coumarin osthole is a dominant bioactive ingredient of the natural Cnidium monnieri plant commonly used for traditional Chinese herbal medicines for therapies and treatments including antipruritus and antidermatitis. However, the molecular mechanism underlying the action of osthole remains unclear. In this study, we report that osthole exerts an antipruritic effect through selective inhibition of Ca2+-permeable and thermosensitive transient receptor potential vanilloid 3 (TRPV3) cation channels that are primarily expressed in the keratinocytes of the skin. Coumarin osthole was identified as an inhibitor of TRPV3 channels transiently expressed in HEK293 cells in a calcium fluorescent assay. Inhibition of the TRPV3 current by osthole and its selectivity were further confirmed by whole-cell patch clamp recordings of TRPV3-expressing HEK293 cells and mouse primary cultured keratinocytes. Behavioral evaluation demonstrated that inhibition of TRPV3 by osthole or silencing by knockout of the TRPV3 gene significantly reduced the scratching induced by either acetone-ether-water or histamine in localized rostral neck skin in mice. Taken together, our findings provide a molecular basis for use of natural coumarin osthole from the C. monnieri plant in antipruritic or skin care therapy, thus establishing a significant role of the TRPV3 channel in chronic itch signaling or acute histamine-dependent itch sensation.
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Affiliation(s)
- Xiao-Ying Sun
- Department of Pharmacology, Qingdao University School of Pharmacy, Qingdao, China
| | - Li-Lan Sun
- Department of Pharmacology, Qingdao University School of Pharmacy, Qingdao, China
| | - Hang Qi
- Department of Pharmacology, Qingdao University School of Pharmacy, Qingdao, China
| | - Qin Gao
- Department of Pharmacology, Qingdao University School of Pharmacy, Qingdao, China
| | - Gong-Xin Wang
- Department of Pharmacology, Qingdao University School of Pharmacy, Qingdao, China
| | - Ning-Ning Wei
- Department of Pharmacology, Qingdao University School of Pharmacy, Qingdao, China
| | - KeWei Wang
- Department of Pharmacology, Qingdao University School of Pharmacy, Qingdao, China
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140
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Napolitano M, Marasca C, Fabbrocini G, Patruno C. Adult atopic dermatitis: new and emerging therapies. Expert Rev Clin Pharmacol 2018; 11:867-878. [PMID: 30073901 DOI: 10.1080/17512433.2018.1507734] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
INTRODUCTION Adult atopic dermatitis (AD) is very difficult to manage. Indeed, AD in adults is frequently refractory to topical treatment, especially with regards to the persistent form. Therefore, long-term treatment with oral immunosuppressive therapy is often required to control the burden of the disease, prevent flare-ups and achieve better patient quality of life outcomes. Areas covered: In the last decade the better understanding of AD pathogenesis has been used to improve treatment strategies with many emerging therapeutics options. Epidermal barrier impairment often plays the initial role in the initiation of the disease. Moreover, T helper 2 cytokines interleukin (IL)-4 and IL-13 and their downstream effects are prominent in AD, with pleiotropic effects on the innate and adaptive immune system. Targeting these cells, their products or receptors appears to be a reasonable therapeutic strategy. Expert commentary: In the next years, many therapeutic options for adult AD will be available. Clinical trials showed that JAK inhibitors, PDE-4 inhibitors and monoclonal antibodies against some IL (IL-4, IL 13, IL-17, IL-22, IL-31) seem to be the most promising drugs, but dermatologists will have to evaluate their effectiveness and safety in clinical practice.
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Affiliation(s)
- Maddalena Napolitano
- a Department of Medicine and Health Sciences Vincenzo Tiberio , University of Molise , Campobasso , Italy
| | - Claudio Marasca
- b Section of Dermatology, Department of Clinical Medicine and Surgery , University of Naples Federico II , Naples , Italy
| | - Gabriella Fabbrocini
- b Section of Dermatology, Department of Clinical Medicine and Surgery , University of Naples Federico II , Naples , Italy
| | - Cataldo Patruno
- b Section of Dermatology, Department of Clinical Medicine and Surgery , University of Naples Federico II , Naples , Italy
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141
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S1PR3 Mediates Itch and Pain via Distinct TRP Channel-Dependent Pathways. J Neurosci 2018; 38:7833-7843. [PMID: 30082422 DOI: 10.1523/jneurosci.1266-18.2018] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 07/06/2018] [Accepted: 07/14/2018] [Indexed: 11/21/2022] Open
Abstract
Sphingosine 1-phosphate (S1P) is a bioactive signaling lipid associated with a variety of chronic pain and itch disorders. S1P signaling has been linked to cutaneous pain, but its role in itch has not yet been studied. Here, we find that S1P triggers itch and pain in male mice in a concentration-dependent manner, with low levels triggering acute itch alone and high levels triggering both pain and itch. Ca2+ imaging and electrophysiological experiments revealed that S1P signals via S1P receptor 3 (S1PR3) and TRPA1 in a subset of pruriceptors and via S1PR3 and TRPV1 in a subset of heat nociceptors. Consistent with these findings, S1P-evoked itch behaviors are selectively lost in mice lacking TRPA1, whereas S1P-evoked acute pain and heat hypersensitivity are selectively lost in mice lacking TRPV1. We conclude that S1P acts via different cellular and molecular mechanisms to trigger itch and pain. Our discovery elucidates the diverse roles that S1P signaling plays in somatosensation and provides insight into how itch and pain are discriminated in the periphery.SIGNIFICANCE STATEMENT Itch and pain are major health problems with few effective treatments. Here, we show that the proinflammatory lipid sphingosine 1-phosphate (S1P) and its receptor, S1P receptor 3 (S1PR3), trigger itch and pain behaviors via distinct molecular and cellular mechanisms. Our results provide a detailed understanding of the roles that S1P and S1PR3 play in somatosensation, highlighting their potential as targets for analgesics and antipruritics, and provide new insight into the mechanistic underpinnings of itch versus pain discrimination in the periphery.
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142
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Barbero R, Vercelli C, Cuniberti B, Della Valle MF, Martano M, Re G. Expression of functional TRPV1 receptor in primary culture of canine keratinocytes. J Vet Pharmacol Ther 2018; 41:795-804. [PMID: 30043987 DOI: 10.1111/jvp.12694] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Revised: 05/18/2018] [Accepted: 06/11/2018] [Indexed: 12/20/2022]
Abstract
The interest for the endovanilloid system and for transient receptor potential vanilloid 1 (TRPV1) is continuously increasing, due to their involvement in inflammation, nociception and pruritus. Even if TRPV1 enrolment was highlighted in both physiological and pathological conditions, some aspects remain unclear, mostly in veterinary medicine. This study aimed to verify the expression and functionality of TRPV1 in canine keratinocytes to investigate in vitro the role of TRPV1 in these cells that are involved in different cutaneous pathologies. Keratinocytes primary cultures were isolated from bioptical samples and cultivated. Binding assay (using 3 [H]-resiniferatoxin), displacement assay (in the presence of 1.2 nM 3 [H]-resiniferatoxin) and functional assays (in the presence of 1 μCi/45 Ca2+ ) with vanilloid agonists and antagonists, specifically addressed to TRPV1 receptor, were performed. Binding assay demonstrated the presence of measurable concentrations of TRPV1 (Bmax = 1,240 ± 120 fmol/mg protein; Kd = 0.01 ± 0.004 nM). Displacement assay highlighted the highest affinity for resiniferatoxin (RTX) and 5-iodo-resiniferatoxin (5-I-RTX), among agonists and antagonists, respectively. The same compounds results as the most potent in the functional assays. This study demonstrated the identification and the characterization of TRPV1 receptor in primary canine keratinocytes cultures. The results are promising for a clinical use, but further in vivo investigations are required.
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Affiliation(s)
- Raffaella Barbero
- SC of Serology, Istituto Zooprofilattico Sperimentale Piemonte Liguria e Valle d'Aosta, Turin, Italy
| | - Cristina Vercelli
- Department of Veterinary Sciences of Turin, University of Turin, Turin, Italy
| | - Barbara Cuniberti
- Royal Dick School of Veterinary Medicine, The University of Edinburg, Edinburg, Ireland
| | | | - Marina Martano
- Department of Veterinary Sciences of Turin, University of Turin, Turin, Italy
| | - Giovanni Re
- Department of Veterinary Sciences of Turin, University of Turin, Turin, Italy
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143
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Zhou JR, Shirasaki T, Soeda F, Yokomizo K, Takahama K. Direct Potentiation of Capsaicin Current by Histamine and Its Effect by Suplatast on Rat Trigeminal Ganglia Neurons. Pharmacology 2018; 102:37-41. [PMID: 29768271 DOI: 10.1159/000489043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Accepted: 03/26/2018] [Indexed: 11/19/2022]
Abstract
In this study, we investigated the effect of histamine on capsaicin-induced current and its influence by suplatast in rat trigeminal ganglia neurons using a patch-clamp technique. We found that histamine directly potentiated capsaicin-induced currents in rat sensory neurons, and suplatast had little effect on this potentiation. Since it has been known that suplatast suppresses histamine release from mast cells, it is possible that suplatast inhibits the activation of nociceptive fibers in the pathological condition via prevention of histamine-induced potentiation of the transient receptor potential vanilloid 1 receptor-mediated currents.
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Affiliation(s)
- Jian-Rong Zhou
- Department of Environmental and Molecular Health Sciences, Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan.,Department of Presymptomatic Medical Pharmacology, Faculty of Pharmaceutical Sciences, Sojo University, Kumamoto, Japan
| | - Tetsuya Shirasaki
- Department of Environmental and Molecular Health Sciences, Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan.,Department of Environmental and Health Sciences, Faculty of Pharmaceutical Science, Kyushu University of Health and Welfare, Nobeoka, Japan
| | - Fumio Soeda
- Department of Environmental and Molecular Health Sciences, Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan.,Laboratory of Hygienic Chemistry, Daiichi University of Pharmacy, Fukuoka, Japan
| | - Kazumi Yokomizo
- Department of Presymptomatic Medical Pharmacology, Faculty of Pharmaceutical Sciences, Sojo University, Kumamoto, Japan
| | - Kazuo Takahama
- Department of Environmental and Molecular Health Sciences, Graduate School of Pharmaceutical Sciences, Kumamoto University, Kumamoto, Japan.,Faculty of Health Science, Kumamoto Health Science University, Kumamoto, Japan
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144
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Doherty TA, White AA. Postural orthostatic tachycardia syndrome and the potential role of mast cell activation. Auton Neurosci 2018; 215:83-88. [PMID: 30033040 DOI: 10.1016/j.autneu.2018.05.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Revised: 05/03/2018] [Accepted: 05/03/2018] [Indexed: 12/18/2022]
Abstract
Though a sizeable amount of data connects mast cell activity to the neurologic system, less is known about the true clinical implications of this relationship. Even less is understood about treatment strategies in those with both allergic and neurologic complaints. This is particularly true in postural orthostatic tachycardia syndrome (POTS), a common type of dysautonomia, where patients are burdened by symptoms of orthostatic cerebral hypoperfusion and several other comorbidities that are likely influenced by autonomic tone. Some patients describe characteristic allergic symptoms, in the absence of typical IgE mediated triggers, and also improvement with traditional mast cell directed medications. Further work is necessary to determine whether these anecdotal observations are valid. The answer to this question will likely be addressed as the mechanisms of POTS are better characterized, which may include a phenotype with distinct mast cell involvement.
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Affiliation(s)
- Taylor A Doherty
- Division of Rheumatology, Allergy and Immunology, University of California, San Diego, United States
| | - Andrew A White
- Division of Allergy, Asthma and Immunology, Scripps Clinic, 3811 Valley Centre Drive, S99, San Diego, CA 92130, United States.
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145
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Voisin T, Bouvier A, Chiu IM. Neuro-immune interactions in allergic diseases: novel targets for therapeutics. Int Immunol 2018; 29:247-261. [PMID: 28814067 DOI: 10.1093/intimm/dxx040] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Accepted: 07/05/2017] [Indexed: 12/13/2022] Open
Abstract
Recent studies have highlighted an emerging role for neuro-immune interactions in mediating allergic diseases. Allergies are caused by an overactive immune response to a foreign antigen. The peripheral sensory and autonomic nervous system densely innervates mucosal barrier tissues including the skin, respiratory tract and gastrointestinal (GI) tract that are exposed to allergens. It is increasingly clear that neurons actively communicate with and regulate the function of mast cells, dendritic cells, eosinophils, Th2 cells and type 2 innate lymphoid cells in allergic inflammation. Several mechanisms of cross-talk between the two systems have been uncovered, with potential anatomical specificity. Immune cells release inflammatory mediators including histamine, cytokines or neurotrophins that directly activate sensory neurons to mediate itch in the skin, cough/sneezing and bronchoconstriction in the respiratory tract and motility in the GI tract. Upon activation, these peripheral neurons release neurotransmitters and neuropeptides that directly act on immune cells to modulate their function. Somatosensory and visceral afferent neurons release neuropeptides including calcitonin gene-related peptide, substance P and vasoactive intestinal peptide, which can act on type 2 immune cells to drive allergic inflammation. Autonomic neurons release neurotransmitters including acetylcholine and noradrenaline that signal to both innate and adaptive immune cells. Neuro-immune signaling may play a central role in the physiopathology of allergic diseases including atopic dermatitis, asthma and food allergies. Therefore, getting a better understanding of these cellular and molecular neuro-immune interactions could lead to novel therapeutic approaches to treat allergic diseases.
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Affiliation(s)
- Tiphaine Voisin
- Department of Microbiology and Immunobiology, Division of Immunology, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, MA 02115, USA
| | - Amélie Bouvier
- Department of Microbiology and Immunobiology, Division of Immunology, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, MA 02115, USA
| | - Isaac M Chiu
- Department of Microbiology and Immunobiology, Division of Immunology, Harvard Medical School, 77 Avenue Louis Pasteur, Boston, MA 02115, USA
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146
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Jiang YM, Huang C, Peng Z, Han SL, Li WG, Zhu MX, Xu TL. Acidosis counteracts itch tachyphylaxis to consecutive pruritogen exposure dependent on acid-sensing ion channel 3. Mol Pain 2018; 13:1744806917721114. [PMID: 28745101 PMCID: PMC5533257 DOI: 10.1177/1744806917721114] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Tachyphylaxis of itch refers to a markedly reduced scratching response to consecutive exposures of a pruritogen, a process thought to protect against tissue damage by incessant scratching and to become disrupted in chronic itch. Here, we report that a strong stimulation of the Mas-related G-protein-coupled receptor C11 by its agonist, Ser-Leu-Ile-Gly-Arg-Leu-NH2 (SL-NH2) or bovine adrenal medulla 8-22 peptide, via subcutaneous injection in mice induces tachyphylaxis to the subsequent application of SL-NH2 to the same site. Notably, co-application of acid and SL-NH2 following the initial injection of the pruritogen alone counteracted itch tachyphylaxis by augmenting the scratching behaviors in wild-type but not in acid-sensing ion channel 3-null, animals. Using an activity-dependent silencing strategy, we identified that acid-sensing ion channel 3-mediated itch enhancement mainly occurred via the Mas-related G-protein-coupled receptor C11-responsive sensory neurons. Together, our results indicate that acid-sensing ion channel 3, activated by concomitant acid and certain pruritogens, constitute a novel signaling pathway that counteracts itch tachyphylaxis to successive pruritogenic stimulation, which likely contributes to chronic itch associated with tissue acidosis.
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Affiliation(s)
- Yi-Ming Jiang
- 1 Department of Anatomy and Physiology, Collaborative Innovation Center for Brain Science, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Chen Huang
- 1 Department of Anatomy and Physiology, Collaborative Innovation Center for Brain Science, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Zhong Peng
- 1 Department of Anatomy and Physiology, Collaborative Innovation Center for Brain Science, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Shao-Ling Han
- 1 Department of Anatomy and Physiology, Collaborative Innovation Center for Brain Science, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Wei-Guang Li
- 1 Department of Anatomy and Physiology, Collaborative Innovation Center for Brain Science, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Michael Xi Zhu
- 2 Department of Integrative Biology and Pharmacology, University of Texas Health Science Center, Houston, TX, USA
| | - Tian-Le Xu
- 1 Department of Anatomy and Physiology, Collaborative Innovation Center for Brain Science, Shanghai Jiao Tong University School of Medicine, Shanghai, China
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147
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Pluskal T, Weng JK. Natural product modulators of human sensations and mood: molecular mechanisms and therapeutic potential. Chem Soc Rev 2018; 47:1592-1637. [PMID: 28933478 DOI: 10.1039/c7cs00411g] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Humans perceive physical information about the surrounding environment through their senses. This physical information is registered by a collection of highly evolved and finely tuned molecular sensory receptors. A multitude of bioactive, structurally diverse ligands have evolved in nature that bind these molecular receptors. The complex, dynamic interactions between the ligands and the receptors lead to changes in our sensory perception or mood. Here, we review our current knowledge of natural products and their derived analogues that interact specifically with human G protein-coupled receptors, ion channels, and nuclear hormone receptors to modulate the sensations of taste, smell, temperature, pain, and itch, as well as mood and its associated behaviour. We discuss the molecular and structural mechanisms underlying such interactions and highlight cases where subtle differences in natural product chemistry produce drastic changes in functional outcome. We also discuss cases where a single compound triggers complex sensory or behavioural changes in humans through multiple mechanistic targets. Finally, we comment on the therapeutic potential of the reviewed area of research and draw attention to recent technological developments in genomics, metabolomics, and metabolic engineering that allow us to tap the medicinal properties of natural product chemistry without taxing nature.
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Affiliation(s)
- Tomáš Pluskal
- Whitehead Institute for Biomedical Research, 455 Main Street, Cambridge, MA 02142, USA.
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148
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Antipruritic Effects of Botulinum Neurotoxins. Toxins (Basel) 2018; 10:toxins10040143. [PMID: 29596343 PMCID: PMC5923309 DOI: 10.3390/toxins10040143] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Revised: 03/27/2018] [Accepted: 03/27/2018] [Indexed: 12/20/2022] Open
Abstract
This review explores current evidence to demonstrate that botulinum neurotoxins (BoNTs) exert antipruritic effects. Both experimental and clinical conditions in which botulinum neurotoxins have been applied for pruritus relief will be presented and significant findings will be highlighted. Potential mechanisms underlying antipruritic effects will also be discussed and ongoing challenges and unmet needs will be addressed.
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149
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A Study and Review of Effects of Botulinum Toxins on Mast Cell Dependent and Independent Pruritus. Toxins (Basel) 2018; 10:toxins10040134. [PMID: 29570628 PMCID: PMC5923300 DOI: 10.3390/toxins10040134] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Revised: 03/21/2018] [Accepted: 03/21/2018] [Indexed: 12/03/2022] Open
Abstract
Pruriceptive itch originates following activation of peripheral sensory nerve terminals when pruritogens come in contact with the skin. The ability of botulinum neurotoxins (BoNTs) to attenuate transmitter release from afferent terminals provides a rationale for studying its effect on pruritus. This study investigated the effects of BoNT/A1 and BoNT/B1 on mast cell dependent (Compound 48/80:48/80) and independent (Chloroquine:CQ) scratching. C57Bl/6 male mice received intradermal injection of 1.5 U of BoNT/A1, BoNT/B1 or saline 2, 7, 14 and 21 days prior to ipsilateral 48/80 or CQ at the nape of the neck. Ipsilateral hind paw scratching was determined using an automated recording device. The effect of BoNTs on 48/80 mediated mast cell degranulation was analyzed in human and murine mast cells and the presence of SNAREs was determined using qPCR, immunostaining and Western blot. Pre-treatment with BoNT/A1 and BoNT/B1 reduced 48/80 and CQ induced scratching behavior starting on day 2 with reversal by day 21. Both serotypes inhibited 48/80 induced mast cell degranulation. qPCR and immunostaining detected SNAP-25 mRNA and protein, respectively, in mast cells, however, Western blots did not. This study demonstrates the long-lasting anti-pruritic effects of two BoNT serotypes, in a murine pruritus model using two different mechanistically driven pruritogens. These data also indicate that BoNTs may have a direct effect upon mast cell degranulation.
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Chigbu DI, Minhas BK. Immunopathology of Allergic Conjunctivitis. EUROPEAN MEDICAL JOURNAL 2018. [DOI: 10.33590/emj/10312711] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Allergic conjunctivitis is predominantly an immunoglobulin E-mediated hypersensitivity reaction to environmental allergens. Allergic diseases affect >30% of the world’s population, of which 40% report associated ocular manifestations. Cellular and soluble mediators play a major role in the pathophysiology of allergic conjunctivitis. Mast cells, which are major effector cells of allergic conjunctivitis, undergo activation and degranulation to release histamine, tryptase, prostaglandins, leukotrienes, and cytokines. These mediators play important roles in immunopathological mechanisms that generate the clinical manifestations of allergic conjunctivitis. These clinical features include conjunctival hyperaemia, chemosis, tearing, itching, papillae, mucus discharge, and eyelid oedema. Histamine mediates the early phase of the allergic immune response, whereas lipid mediators and cytokines are involved in the late phase of the immunopathology of allergic conjunctivitis. Current management of allergic conjunctivitis includes non-pharmacological approaches such as allergen avoidance and palliative therapy, whereas pharmacological therapeutic modalities may include antihistamine–mast cell stabiliser combination ophthalmic formulations and allergen-specific immunotherapy. Furthermore, as cellular and soluble mediators play a pivotal role in the immunopathogenesis and immunopathology of allergic conjunctivitis, development of immunotherapeutic and pharmacotherapeutic agents specific to these mediators can enhance the therapeutic index and safety profile of anti-allergy treatment.
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Affiliation(s)
- DeGaulle I. Chigbu
- Pennsylvania College of Optometry, Salus University, Elkins Park, Pennsylvania, USA
| | - Bhawanjot K. Minhas
- Pennsylvania College of Optometry, Salus University, Elkins Park, Pennsylvania, USA
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