1
|
Lin S, Liu X, Jiang J, Ge W, Zhang Y, Li F, Tao Q, Liu S, Li M, Chen H. The involvement of keratinocytes in pruritus of chronic inflammatory dermatosis. Exp Dermatol 2024; 33:e15142. [PMID: 39032085 DOI: 10.1111/exd.15142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 07/02/2024] [Accepted: 07/09/2024] [Indexed: 07/22/2024]
Abstract
Frequent itching and incessant scratching are commonly observed in various chronic inflammatory skin conditions, including atopic dermatitis and psoriasis. The persistent and prolonged nature of pruritus can worsen one's quality of life. Keratinocytes (KCs), the predominant cells of the epidermis, have been confirmed to interact with sensory neurons and immune cells and be involved in chronic skin inflammatory diseases associated with pruritus. Initially, KCs and sensory neurons form a unique synapse-like connection within the epidermis, serving as the structural foundation for their interaction. Additionally, several receptors, including toll-like receptors and protease-activated receptor 2, expressed on KCs, become activated in an inflammatory milieu. On the one hand, activated KCs are sources of pro-inflammatory cytokines and neurotrophic factors, such as adenosine triphosphate, thymic stromal lymphopoietin, and nerve growth factor, which directly or indirectly participate in stimulating sensory neurons, thereby contributing to the itch sensations. On the other hand, KCs also function as primary transducers alongside intraepidermal nerve endings, directly initiating pruritic responses. This review summarizes the current literature and highlights the critical role of KCs in the development and persistence of chronic itch in inflammatory skin disorders.
Collapse
Affiliation(s)
- Shiying Lin
- Department of Dermatology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xin Liu
- Department of Dermatology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jian Jiang
- Department of Dermatology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Wenqiang Ge
- Department of Neurobiology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Yinlian Zhang
- Shenzhen Qianhai Shekou Free Trade Zone Hospital, Shenzhen, China
- Institute of Biomedical and Health Engineering, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Fei Li
- Department of Dermatology, Huazhong University of Science and Technology Union Shenzhen Hospital, Shenzhen, China
- Department of Dermatology, The 6th Affiliated Hospital of Shenzhen University Health Science Center, Shenzhen, China
- Guangdong Key Laboratory for Biomedical Measurements and Ultrasound Imaging, National-Regional Key Technology Engineering Laboratory for Medical Ultrasound, School of Biomedical Engineering, Shenzhen University Medical School, Shenzhen, China
| | - Qingxiao Tao
- Department of Dermatology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Suwen Liu
- Department of Dermatology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Man Li
- Department of Neurobiology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Hongxiang Chen
- Department of Dermatology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- Department of Dermatology, Huazhong University of Science and Technology Union Shenzhen Hospital, Shenzhen, China
- Department of Dermatology, The 6th Affiliated Hospital of Shenzhen University Health Science Center, Shenzhen, China
| |
Collapse
|
2
|
Yook HJ, Lee JH. Prurigo Nodularis: Pathogenesis and the Horizon of Potential Therapeutics. Int J Mol Sci 2024; 25:5164. [PMID: 38791201 PMCID: PMC11121340 DOI: 10.3390/ijms25105164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2024] [Revised: 04/18/2024] [Accepted: 04/18/2024] [Indexed: 05/26/2024] Open
Abstract
Chronic pruritus that lasts for over 6 weeks can present in various forms, like papules, nodules, and plaque types, with prurigo nodularis (PN) being the most prevalent. The pathogenesis of PN involves the dysregulation of immune cell-neural circuits and is associated with peripheral neuropathies, possibly due to chronic scratching. PN is a persistent and challenging condition, involving complex interactions among the skin, immune system, and nervous system. Lesional skin in PN exhibits the infiltration of diverse immune cells like T cells, eosinophils, macrophages, and mast cells, leading to the release of inflammatory cytokines and itch-inducing substances. Activated sensory nerve fibers aggravate pruritus by releasing neurotransmitters, perpetuating a vicious cycle of itching and scratching. Traditional treatments often fail, but recent advancements in understanding the inflammatory and itch transmission mechanisms of PN have paved the way for innovative therapeutic approaches, which are explored in this review.
Collapse
Affiliation(s)
| | - Ji Hyun Lee
- Department of Dermatology, Seoul St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, #222 Banpo-daero, Seocho-gu, Seoul 06591, Republic of Korea
| |
Collapse
|
3
|
Shao Y, Wang D, Zhu Y, Xiao Z, Jin T, Peng L, Shen Y, Tang H. Molecular mechanisms of pruritus in prurigo nodularis. Front Immunol 2023; 14:1301817. [PMID: 38077377 PMCID: PMC10701428 DOI: 10.3389/fimmu.2023.1301817] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Accepted: 11/13/2023] [Indexed: 12/18/2023] Open
Abstract
Pruritus is the most common symptom of dermatological disorders, and prurigo nodularis (PN) is notorious for intractable and severe itching. Conventional treatments often yield disappointing outcomes, significantly affecting patients' quality of life and psychological well-being. The pathogenesis of PN is associated with a self-sustained "itch-scratch" vicious cycle. Recent investigations of PN-related itch have partially revealed the intricate interactions within the cutaneous neuroimmune network; however, the underlying mechanism remains undetermined. Itch mediators play a key role in pruritus amplification in PN and understanding their action mechanism will undoubtedly lead to the development of novel targeted antipruritic agents. In this review, we describe a series of pruritogens and receptors involved in mediating itching in PN, including cytokines, neuropeptides, extracellular matrix proteins, vasculogenic substances, ion channels, and intracellular signaling pathways. Moreover, we provide a prospective outlook on potential therapies based on existing findings.
Collapse
Affiliation(s)
| | | | | | | | | | | | | | - Hui Tang
- Department of Dermatology, Huashan Hospital, Fudan University, Shanghai, China
| |
Collapse
|
4
|
Shang L, Zhao S, Shi H, Xing X, Zhang J, He Y. Nerve growth factor mediates activation of transient receptor potential vanilloid 1 in neurogenic pruritus of psoriasis. Int Immunopharmacol 2023; 118:110063. [PMID: 37004343 DOI: 10.1016/j.intimp.2023.110063] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Revised: 03/04/2023] [Accepted: 03/19/2023] [Indexed: 04/03/2023]
Abstract
Pruritus is a common and painful symptom in psoriasis with profoundly negative impacts on quality of life. The underlying mechanisms of pruritus are complex and multifactorial, and accumulating evidence suggests that pruritus induced by neurogenic inflammation predominates in psoriasis. Nerve growth factor (NGF) -mediated transient receptor potential vanilloid receptor 1(TRPV1) pathway has emerged as a crucial node in the regulation of neurogenic pruritus. TRPV1 appears coupled to most pruritus-specific molecules via the neuro-immune axis. While the modes of regulation differ for each axis, TRPV1 is involved in substantial biochemical crosstalk-causing feedback loops with significant effects on neurogenic pruritus. Therefore, TRPV1 has emerged as a target molecular in drug development for pruritus in psoriasis. However, no significant clinical progress occurred in the development of systemic TRPV1 antagonists due to elevated core temperature. Thus, topical application of TRPV1 antagonists and interference with mediators linked to the TRPV1 activation pathway may be promising therapeutic options to ameliorate pruritus. This Review focuses on recent advances in complicated regulation of NGF-mediated TRPV1 pathway in psoriatic neurogenic pruritus, as well as the therapeutic options that arise from the dissection of the pathway.
Collapse
|
5
|
Tominaga M, Takamori K. Peripheral itch sensitization in atopic dermatitis. Allergol Int 2022; 71:265-277. [PMID: 35624035 DOI: 10.1016/j.alit.2022.04.003] [Citation(s) in RCA: 38] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2022] [Accepted: 04/06/2022] [Indexed: 02/07/2023] Open
Abstract
Atopic dermatitis is a skin disorder caused by skin dryness and barrier dysfunction, resulting in skin inflammation and chronic itch (or pruritus). The pathogenesis of atopic dermatitis is thought to be initiated by a lowering of the itch threshold due to dry skin. This lowering of the itch threshold is at least partially due to the increase in intraepidermal nerve fibers and sensitization of sensory nerves by interleukin (IL)-33 produced and secreted by keratinocytes. Such skin is easily prone to itch due to mechanical stimuli, such as rubbing of clothing and chemical stimuli from itch mediators. In patients with atopic dermatitis, once itch occurs, further itch is induced by scratching, and the associated scratching breaks down the skin barrier. Disruption of the skin barrier allows entry into the epidermis of external foreign substances, such as allergens derived from house dust mites, leading to an increased induction of type 2 inflammatory responses. As a result, type 2 cytokines IL-4, IL-13, and IL-31 are mainly secreted by Th2 cells, and their action on sensory nerve fibers causes further itch sensitization. These sequences of events are thought to occur simultaneously in patients with atopic dermatitis, leading to a vicious itch-scratch cycle. This vicious cycle becomes a negative spiral that leads to disease burden. Therefore, controlling itch is essential for the treatment of atopic dermatitis. In this review, we summarize and discuss advances in the mechanisms of peripheral itch sensitization in atopic dermatitis, focusing on skin barrier-neuro-immune triadic connectivity.
Collapse
|
6
|
Camponogara C, Oliveira SM. Are TRPA1 and TRPV1 channel-mediated signalling cascades involved in UVB radiation-induced sunburn? ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2022; 92:103836. [PMID: 35248760 DOI: 10.1016/j.etap.2022.103836] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 02/09/2022] [Accepted: 02/28/2022] [Indexed: 06/14/2023]
Abstract
Burn injuries are underappreciated injuries associated with substantial morbidity and mortality. Overexposure to ultraviolet (UV) radiation has dramatic clinical effects in humans and is a significant public health concern. Although the mechanisms underlying UVB exposure are not fully understood, many studies have made substantial progress in the pathophysiology of sunburn in terms of its molecular aspects in the last few years. It is well established that the transient receptor potential ankyrin 1 (TRPA1), and vanilloid 1 (TRPV1) channels modulate the inflammatory, oxidative, and proliferative processes underlying UVB radiation exposure. However, it is still unknown which mechanisms underlying TRPV1/A1 channel activation are elicited in sunburn induced by UVB radiation. Therefore, in this review, we give an overview of the TRPV1/A1 channel-mediated signalling cascades that may be involved in the pathophysiology of sunburn induced by UVB radiation. These data will undoubtedly help to explain the various features of sunburn and contribute to the development of novel therapeutic approaches to better treat it.
Collapse
Affiliation(s)
- Camila Camponogara
- Graduated Program in Biological Sciences: Toxicological Biochemistry, Federal University of Santa Maria, Santa Maria, RS, Brazil
| | - Sara Marchesan Oliveira
- Graduated Program in Biological Sciences: Toxicological Biochemistry, Federal University of Santa Maria, Santa Maria, RS, Brazil; Department of Biochemistry and Molecular Biology, Centre of Natural and Exact Sciences, Federal University of Santa Maria, Santa Maria, RS, Brazil.
| |
Collapse
|
7
|
Szöllősi AG, Oláh A, Lisztes E, Griger Z, Tóth BI. Pruritus: A Sensory Symptom Generated in Cutaneous Immuno-Neuronal Crosstalk. Front Pharmacol 2022; 13:745658. [PMID: 35321329 PMCID: PMC8937025 DOI: 10.3389/fphar.2022.745658] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Accepted: 02/07/2022] [Indexed: 12/21/2022] Open
Abstract
Pruritus or itch generated in the skin is one of the most widespread symptoms associated with various dermatological and systemic (immunological) conditions. Although many details about the molecular mechanisms of the development of both acute and chronic itch were uncovered in the last 2 decades, our understanding is still incomplete and the clinical management of pruritic conditions is one of the biggest challenges in daily dermatological practice. Recent research revealed molecular interactions between pruriceptive sensory neurons and surrounding cutaneous cell types including keratinocytes, as well as resident and transient cells of innate and adaptive immunity. Especially in inflammatory conditions, these cutaneous cells can produce various mediators, which can contribute to the excitation of pruriceptive sensory fibers resulting in itch sensation. There also exists significant communication in the opposite direction: sensory neurons can release mediators that maintain an inflamed, pruritic tissue-environment. In this review, we summarize the current knowledge about the sensory transduction of pruritus detailing the local intercellular interactions that generate itch. We especially emphasize the role of various pruritic mediators in the bidirectional crosstalk between cutaneous non-neuronal cells and sensory fibers. We also list various dermatoses and immunological conditions associated with itch, and discuss the potential immune-neuronal interactions promoting the development of pruritus in the particular diseases. These data may unveil putative new targets for antipruritic pharmacological interventions.
Collapse
Affiliation(s)
- Attila Gábor Szöllősi
- Department of Immunology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Attila Oláh
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Erika Lisztes
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Zoltán Griger
- Division of Clinical Immunology, Department of Internal Medicine, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Balázs István Tóth
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
- *Correspondence: Balázs István Tóth,
| |
Collapse
|
8
|
Hellenthal KEM, Brabenec L, Gross ER, Wagner NM. TRP Channels as Sensors of Aldehyde and Oxidative Stress. Biomolecules 2021; 11:biom11101401. [PMID: 34680034 PMCID: PMC8533644 DOI: 10.3390/biom11101401] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2021] [Revised: 09/20/2021] [Accepted: 09/22/2021] [Indexed: 12/15/2022] Open
Abstract
The transient receptor potential (TRP) cation channel superfamily comprises more than 50 channels that play crucial roles in physiological processes. TRP channels are responsive to several exogenous and endogenous biomolecules, with aldehydes emerging as a TRP channel trigger contributing to a cellular cascade that can lead to disease pathophysiology. The body is not only exposed to exogenous aldehydes via tobacco products or alcoholic beverages, but also to endogenous aldehydes triggered by lipid peroxidation. In response to lipid peroxidation from inflammation or organ injury, polyunsaturated fatty acids undergo lipid peroxidation to aldehydes, such as 4-hydroxynonenal. Reactive aldehydes activate TRP channels via aldehyde-induced protein adducts, leading to the release of pro-inflammatory mediators driving the pathophysiology caused by cellular injury, including inflammatory pain and organ reperfusion injury. Recent studies have outlined how aldehyde dehydrogenase 2 protects against aldehyde toxicity through the clearance of toxic aldehydes, indicating that targeting the endogenous aldehyde metabolism may represent a novel treatment strategy. An addition approach can involve targeting specific TRP channel regions to limit the triggering of a cellular cascade induced by aldehydes. In this review, we provide a comprehensive summary of aldehydes, TRP channels, and their interactions, as well as their role in pathological conditions and the different therapeutical treatment options.
Collapse
Affiliation(s)
- Katharina E. M. Hellenthal
- Department of Anesthesiology, Intensive Care and Pain Medicine, University Hospital Muenster, 48149 Muenster, Germany; (K.E.M.H.); (L.B.)
| | - Laura Brabenec
- Department of Anesthesiology, Intensive Care and Pain Medicine, University Hospital Muenster, 48149 Muenster, Germany; (K.E.M.H.); (L.B.)
| | - Eric R. Gross
- Department of Anesthesiology, Perioperative and Pain Medicine, Stanford University, Stanford, CA 94305, USA;
| | - Nana-Maria Wagner
- Department of Anesthesiology, Intensive Care and Pain Medicine, University Hospital Muenster, 48149 Muenster, Germany; (K.E.M.H.); (L.B.)
- Correspondence: ; Tel.: +49-251-83-46837
| |
Collapse
|
9
|
Vieyra-Garcia PA, Wolf P. A deep dive into UV-based phototherapy: Mechanisms of action and emerging molecular targets in inflammation and cancer. Pharmacol Ther 2020; 222:107784. [PMID: 33316286 DOI: 10.1016/j.pharmthera.2020.107784] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Accepted: 11/25/2020] [Indexed: 02/07/2023]
Abstract
UV-based phototherapy (including psoralen plus UVA (PUVA), UVB and UVA1) has a long, successful history in the management of numerous cutaneous disorders. Photoresponsive diseases are etiologically diverse, but most involve disturbances in local (and occasionally systemic) inflammatory cells and/or abnormalities in keratinocytes that trigger inflammation. UV-based phototherapy works by regulating the inflammatory component and inducing apoptosis of pathogenic cells. This results in a fascinating and complex network of simultaneous events-immediate transcriptional changes in keratinocytes, immune cells, and pigment cells; the emergence of apoptotic bodies; and the trafficking of antigen-presenting cells in skin-that quickly transform the microenvironment of UV-exposed skin. Molecular elements in this system of UV recognition and response include chromophores, metabolic byproducts, innate immune receptors, neurotransmitters and mediators such as chemokines and cytokines, antimicrobial peptides, and platelet activating factor (PAF) and PAF-like molecules that simultaneously shape the immunomodulatory effects of UV and their interplay with the microbiota of the skin and beyond. Phototherapy's key effects-proapoptotic, immunomodulatory, antipruritic, antifibrotic, propigmentary, and pro-prebiotic-promote clinical improvement in various skin diseases such as psoriasis, atopic dermatitis (AD), graft-versus-host disease (GvHD), vitiligo, scleroderma, and cutaneous T-cell lymphoma (CTCL) as well as prevention of polymorphic light eruption (PLE). As understanding of phototherapy improves, new therapies (UV- and non-UV-based) are being developed that will modify regulatory T-cells (Treg), interact with (resident) memory T-cells and /or utilize agonists and antagonists as well as antibodies targeting soluble molecules such as cytokines and chemokines, transcription factors, and a variety of membrane-associated receptors.
Collapse
Affiliation(s)
- Pablo A Vieyra-Garcia
- Department of Dermatology, Medical University of Graz, Auenbruggerplatz 8, Graz A-8036, Austria.
| | - Peter Wolf
- Department of Dermatology, Medical University of Graz, Auenbruggerplatz 8, Graz A-8036, Austria.
| |
Collapse
|
10
|
Talavera K, Startek JB, Alvarez-Collazo J, Boonen B, Alpizar YA, Sanchez A, Naert R, Nilius B. Mammalian Transient Receptor Potential TRPA1 Channels: From Structure to Disease. Physiol Rev 2019; 100:725-803. [PMID: 31670612 DOI: 10.1152/physrev.00005.2019] [Citation(s) in RCA: 218] [Impact Index Per Article: 43.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The transient receptor potential ankyrin (TRPA) channels are Ca2+-permeable nonselective cation channels remarkably conserved through the animal kingdom. Mammals have only one member, TRPA1, which is widely expressed in sensory neurons and in non-neuronal cells (such as epithelial cells and hair cells). TRPA1 owes its name to the presence of 14 ankyrin repeats located in the NH2 terminus of the channel, an unusual structural feature that may be relevant to its interactions with intracellular components. TRPA1 is primarily involved in the detection of an extremely wide variety of exogenous stimuli that may produce cellular damage. This includes a plethora of electrophilic compounds that interact with nucleophilic amino acid residues in the channel and many other chemically unrelated compounds whose only common feature seems to be their ability to partition in the plasma membrane. TRPA1 has been reported to be activated by cold, heat, and mechanical stimuli, and its function is modulated by multiple factors, including Ca2+, trace metals, pH, and reactive oxygen, nitrogen, and carbonyl species. TRPA1 is involved in acute and chronic pain as well as inflammation, plays key roles in the pathophysiology of nearly all organ systems, and is an attractive target for the treatment of related diseases. Here we review the current knowledge about the mammalian TRPA1 channel, linking its unique structure, widely tuned sensory properties, and complex regulation to its roles in multiple pathophysiological conditions.
Collapse
Affiliation(s)
- Karel Talavera
- Laboratory of Ion Channel Research, Department of Cellular and Molecular Medicine, KU Leuven; VIB Center for Brain and Disease Research, Leuven, Belgium
| | - Justyna B Startek
- Laboratory of Ion Channel Research, Department of Cellular and Molecular Medicine, KU Leuven; VIB Center for Brain and Disease Research, Leuven, Belgium
| | - Julio Alvarez-Collazo
- Laboratory of Ion Channel Research, Department of Cellular and Molecular Medicine, KU Leuven; VIB Center for Brain and Disease Research, Leuven, Belgium
| | - Brett Boonen
- Laboratory of Ion Channel Research, Department of Cellular and Molecular Medicine, KU Leuven; VIB Center for Brain and Disease Research, Leuven, Belgium
| | - Yeranddy A Alpizar
- Laboratory of Ion Channel Research, Department of Cellular and Molecular Medicine, KU Leuven; VIB Center for Brain and Disease Research, Leuven, Belgium
| | - Alicia Sanchez
- Laboratory of Ion Channel Research, Department of Cellular and Molecular Medicine, KU Leuven; VIB Center for Brain and Disease Research, Leuven, Belgium
| | - Robbe Naert
- Laboratory of Ion Channel Research, Department of Cellular and Molecular Medicine, KU Leuven; VIB Center for Brain and Disease Research, Leuven, Belgium
| | - Bernd Nilius
- Laboratory of Ion Channel Research, Department of Cellular and Molecular Medicine, KU Leuven; VIB Center for Brain and Disease Research, Leuven, Belgium
| |
Collapse
|
11
|
Nakahara T, Kido-Nakahara M, Furue M. Potential Role of Endothelin-1 in Atopic Dermatitis. CURRENT TREATMENT OPTIONS IN ALLERGY 2019. [DOI: 10.1007/s40521-019-00206-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
|
12
|
Zheng X, Tai Y, He D, Liu B, Wang C, Shao X, Jordt SE, Liu B. ET AR and protein kinase A pathway mediate ET-1 sensitization of TRPA1 channel: A molecular mechanism of ET-1-induced mechanical hyperalgesia. Mol Pain 2019; 15:1744806919842473. [PMID: 30990108 PMCID: PMC6537062 DOI: 10.1177/1744806919842473] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2019] [Revised: 03/10/2019] [Accepted: 03/11/2019] [Indexed: 12/16/2022] Open
Abstract
Endothelin-1 (ET-1) is a potent endogenous vasoconstrictor that has been widely known as a pain mediator involved in various pain states. Evidence indicates that ET-1 sensitizes transient receptor potential cation channel, subfamily A, member 1 (TRPA1) in vivo. But the molecular mechanisms still remain unknown. We aim to explore whether ET-1 sensitizes TRPA1 in primary sensory neurons and the molecular mechanisms. Ca2+ imaging, immunostaining, electrophysiology, animal behavioral assay combined with pharmacological experiments were performed. ET-1 sensitized TRPA1-mediated Ca2+ responses in human embryonic kidney (HEK)293 cells as well as in cultured native mouse dorsal root ganglion (DRG) neurons. ET-1 also sensitized TRPA1 channel currents. ET-1 sensitized TRPA1 activated by endogenous agonist H2O2. ETA receptor (ETAR) colocalized with TRPA1 in DRG neurons. ET-1-induced TRPA1 sensitization in vivo was mediated via ETAR and protein kinase A (PKA) pathway in HEK293 cells and DRG neurons. Pharmacological blocking of ETAR, PKA, and TRPA1 significantly attenuated ET-1-induced mechanical hyperalgesia in mice. Our results suggest that TRPA1 acts as a molecular target for ET-1, and sensitization of TRPA1 through ETAR-PKA pathway contributes to ET-1-induced mechanical hyperalgesia. Pharmacological targeting of TRPA1 and ETAR-PKA pathway may provide effective strategies to alleviate pain conditions associated with ET-1.
Collapse
Affiliation(s)
- Xiaoli Zheng
- Department of Neurobiology and Acupuncture Research, The Third Clinical Medical College, Zhejiang Chinese Medical University, Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Hangzhou, China
| | - Yan Tai
- Academy of Chinese Medical Sciences, Zhejiang Chinese Medical University, Hangzhou, China
| | - Dongwei He
- Department of Immune-Oncology, The Fourth Hospital of Hebei Medical University, Shijiazhuang, China
| | - Boyu Liu
- Department of Neurobiology and Acupuncture Research, The Third Clinical Medical College, Zhejiang Chinese Medical University, Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Hangzhou, China
| | - Chuan Wang
- Department of Pharmacology, Hebei Medical University, Shijiazhuang, China
| | - Xiaomei Shao
- Department of Neurobiology and Acupuncture Research, The Third Clinical Medical College, Zhejiang Chinese Medical University, Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Hangzhou, China
| | - Sven-Eric Jordt
- Department of Anesthesiology, Duke University School of Medicine, Durham, NC, USA
| | - Boyi Liu
- Department of Neurobiology and Acupuncture Research, The Third Clinical Medical College, Zhejiang Chinese Medical University, Key Laboratory of Acupuncture and Neurology of Zhejiang Province, Hangzhou, China
| |
Collapse
|
13
|
Choi JE, Di Nardo A. Skin neurogenic inflammation. Semin Immunopathol 2018; 40:249-259. [PMID: 29713744 DOI: 10.1007/s00281-018-0675-z] [Citation(s) in RCA: 170] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2017] [Accepted: 03/06/2018] [Indexed: 01/12/2023]
Abstract
The epidermis closely interacts with nerve endings, and both epidermis and nerves produce substances for mutual sustenance. Neuropeptides, like substance P (SP) and calcitonin gene-related protein (CGRP), are produced by sensory nerves in the dermis; they induce mast cells to release vasoactive amines that facilitate infiltration of neutrophils and T cells. Some receptors are more important than others in the generation of itch. The Mas-related G protein-coupled receptors (Mrgpr) family as well as transient receptor potential ankyrin 1 (TRPA1) and protease activated receptor 2(Par2) have important roles in itch and inflammation. The activation of MrgprX1 degranulates mast cells to communicate with sensory nerve and cutaneous cells for developing neurogenic inflammation. Mrgprs and transient receptor potential vanilloid 4 (TRPV4) are crucial for the generation of skin diseases like rosacea, while SP, CGRP, somatostatin, β-endorphin, vasoactive intestinal peptide (VIP), and pituitary adenylate cyclase-activating polypeptide (PACAP) can modulate the immune system during psoriasis development. The increased level of SP, in atopic dermatitis, induces the release of interferon (IFN)-γ, interleukin (IL)-4, tumor necrosis factor (TNF)-α, and IL-10 from the peripheral blood mononuclear leukocytes. We are finally starting to understand the intricate connections between the skin neurons and resident skin cells and how their interaction can be key to controlling inflammation and from there the pathogenesis of diseases like atopic dermatitis, psoriasis, and rosacea.
Collapse
Affiliation(s)
- Jae Eun Choi
- Department of Dermatology, University of California San Diego, 9500 Gilman Drive #0869, La Jolla, CA, 92093, USA
| | - Anna Di Nardo
- Department of Dermatology, University of California San Diego, 9500 Gilman Drive #0869, La Jolla, CA, 92093, USA.
| |
Collapse
|
14
|
Moore C, Gupta R, Jordt SE, Chen Y, Liedtke WB. Regulation of Pain and Itch by TRP Channels. Neurosci Bull 2018; 34:120-142. [PMID: 29282613 PMCID: PMC5799130 DOI: 10.1007/s12264-017-0200-8] [Citation(s) in RCA: 191] [Impact Index Per Article: 31.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Accepted: 10/27/2017] [Indexed: 02/07/2023] Open
Abstract
Nociception is an important physiological process that detects harmful signals and results in pain perception. In this review, we discuss important experimental evidence involving some TRP ion channels as molecular sensors of chemical, thermal, and mechanical noxious stimuli to evoke the pain and itch sensations. Among them are the TRPA1 channel, members of the vanilloid subfamily (TRPV1, TRPV3, and TRPV4), and finally members of the melastatin group (TRPM2, TRPM3, and TRPM8). Given that pain and itch are pro-survival, evolutionarily-honed protective mechanisms, care has to be exercised when developing inhibitory/modulatory compounds targeting specific pain/itch-TRPs so that physiological protective mechanisms are not disabled to a degree that stimulus-mediated injury can occur. Such events have impeded the development of safe and effective TRPV1-modulating compounds and have diverted substantial resources. A beneficial outcome can be readily accomplished via simple dosing strategies, and also by incorporating medicinal chemistry design features during compound design and synthesis. Beyond clinical use, where compounds that target more than one channel might have a place and possibly have advantageous features, highly specific and high-potency compounds will be helpful in mechanistic discovery at the structure-function level.
Collapse
Affiliation(s)
- Carlene Moore
- Department of Neurology, Duke University Medical Center, Durham, NC, 27710, USA
| | - Rupali Gupta
- Department of Neurology, Duke University Medical Center, Durham, NC, 27710, USA
| | - Sven-Eric Jordt
- Department of Anesthesiology, Duke University Medical Center, Durham, NC, 27710, USA
| | - Yong Chen
- Department of Neurology, Duke University Medical Center, Durham, NC, 27710, USA.
| | - Wolfgang B Liedtke
- Department of Neurology, Duke University Medical Center, Durham, NC, 27710, USA.
- Department of Anesthesiology, Duke University Medical Center, Durham, NC, 27710, USA.
| |
Collapse
|
15
|
|
16
|
The molecular and cellular mechanisms of itch and the involvement of TRP channels in the peripheral sensory nervous system and skin. Allergol Int 2017; 66:22-30. [PMID: 28012781 DOI: 10.1016/j.alit.2016.10.003] [Citation(s) in RCA: 78] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2016] [Accepted: 10/14/2016] [Indexed: 12/24/2022] Open
Abstract
Itch is an unpleasant cutaneous sensation that can arise following insect bites, exposure to plant ingredients, and some diseases. Itch can also have idiopathic causes. Itch sensations are thought to protect against external insults and toxic substances. Although itch is not directly lethal, chronic and long lasting itch in certain diseases can worsen quality of life. Therefore, the mechanisms responsible for chronic itch require careful investigation. There is a significant amount of basic research concerning itch, and the effect of various itch mediators on primary sensory neurons have been studied. Interestingly, many mediators of itch involve signaling related to transient receptor potential (TRP) channels. TRP channels, especially thermosensitive TRP channels, are expressed by primary sensory neurons and skin keratinocytes, which receive multimodal stimuli, including those that cause itch sensations. Here we review the molecular and cellular mechanisms of itch and the involvement of TRP channels in mediating itch sensations.
Collapse
|
17
|
Kodji X, Aubdool AA, Brain SD. Evidence for physiological and pathological roles for sensory nerves in the microvasculature and skin. Curr Res Transl Med 2016; 64:195-201. [PMID: 27939458 DOI: 10.1016/j.retram.2016.09.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2016] [Accepted: 09/17/2016] [Indexed: 11/25/2022]
Abstract
This review highlights the progress from the initial finding of neurogenic inflammation up to the most recent development in the field of sensory nerves research, focusing on their roles in the microvasculature and the skin. Recent discovery of Transient Receptor Potential (TRP) channels highlight their important roles in detecting a range of environmental stimuli, including chemical and temperature. This provides us novel mechanisms for driving neurogenic inflammation upstream of neuropeptide release in addition to promising potential therapeutic targets in various diseases, including pain, itching and skin inflammation.
Collapse
Affiliation(s)
- X Kodji
- Cardiovascular Division, British Heart Foundation Centre of Excellence, King's College London, Faculty of Life Sciences and Medicine, 150, Stamford Street, SE1 9NH London, UK
| | - A A Aubdool
- Cardiovascular Division, British Heart Foundation Centre of Excellence, King's College London, Faculty of Life Sciences and Medicine, 150, Stamford Street, SE1 9NH London, UK
| | - S D Brain
- Cardiovascular Division, British Heart Foundation Centre of Excellence, King's College London, Faculty of Life Sciences and Medicine, 150, Stamford Street, SE1 9NH London, UK.
| |
Collapse
|
18
|
Chen Y, Fang Q, Wang Z, Zhang JY, MacLeod AS, Hall RP, Liedtke WB. Transient Receptor Potential Vanilloid 4 Ion Channel Functions as a Pruriceptor in Epidermal Keratinocytes to Evoke Histaminergic Itch. J Biol Chem 2016; 291:10252-62. [PMID: 26961876 PMCID: PMC4858974 DOI: 10.1074/jbc.m116.716464] [Citation(s) in RCA: 94] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Indexed: 12/25/2022] Open
Abstract
TRPV4 ion channels function in epidermal keratinocytes and in innervating sensory neurons; however, the contribution of the channel in either cell to neurosensory function remains to be elucidated. We recently reported TRPV4 as a critical component of the keratinocyte machinery that responds to ultraviolet B (UVB) and functions critically to convert the keratinocyte into a pain-generator cell after excess UVB exposure. One key mechanism in keratinocytes was increased expression and secretion of endothelin-1, which is also a known pruritogen. Here we address the question of whether TRPV4 in skin keratinocytes functions in itch, as a particular form of “forefront” signaling in non-neural cells. Our results support this novel concept based on attenuated scratching behavior in response to histaminergic (histamine, compound 48/80, endothelin-1), not non-histaminergic (chloroquine) pruritogens in Trpv4 keratinocyte-specific and inducible knock-out mice. We demonstrate that keratinocytes rely on TRPV4 for calcium influx in response to histaminergic pruritogens. TRPV4 activation in keratinocytes evokes phosphorylation of mitogen-activated protein kinase, ERK, for histaminergic pruritogens. This finding is relevant because we observed robust anti-pruritic effects with topical applications of selective inhibitors for TRPV4 and also for MEK, the kinase upstream of ERK, suggesting that calcium influx via TRPV4 in keratinocytes leads to ERK-phosphorylation, which in turn rapidly converts the keratinocyte into an organismal itch-generator cell. In support of this concept we found that scratching behavior, evoked by direct intradermal activation of TRPV4, was critically dependent on TRPV4 expression in keratinocytes. Thus, TRPV4 functions as a pruriceptor-TRP in skin keratinocytes in histaminergic itch, a novel basic concept with translational-medical relevance.
Collapse
Affiliation(s)
| | | | | | | | | | | | - Wolfgang B Liedtke
- From the Departments of Neurology, Neurobiology, and Anesthesiology, Duke University Medical Center, Durham, North Carolina 27710 and Neurology Clinics for Headache, Head Pain and Trigeminal Sensory Disorders, Duke University Medical Center, Durham, North Carolina 27705
| |
Collapse
|
19
|
Pryde DC, Marron B, West CG, Reister S, Amato G, Yoger K, Padilla K, Turner J, Swain NA, Cox PJ, Skerratt SE, Ryckmans T, Blakemore DC, Warmus J, Gerlach AC. The discovery of a potent series of carboxamide TRPA1 antagonists. MEDCHEMCOMM 2016. [DOI: 10.1039/c6md00387g] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Potent and selective carboxamide TRPA1 antagonists were identified by high throughput screening, with efficacy demonstrated in a topical inflammation model.
Collapse
Affiliation(s)
- D. C. Pryde
- Pfizer Worldwide Medicinal Chemistry
- Neuroscience and Pain Research Unit
- Great Abington
- UK
| | | | | | | | | | | | | | - J. Turner
- Neuroscience and Pain Research Unit
- Great Abington
- UK
| | - N. A. Swain
- Pfizer Worldwide Medicinal Chemistry
- Neuroscience and Pain Research Unit
- Great Abington
- UK
| | - P. J. Cox
- Neuroscience and Pain Research Unit
- Great Abington
- UK
| | - S. E. Skerratt
- Pfizer Worldwide Medicinal Chemistry
- Neuroscience and Pain Research Unit
- Great Abington
- UK
| | - T. Ryckmans
- Pfizer Worldwide Medicinal Chemistry
- Sandwich
- UK
| | - D. C. Blakemore
- Pfizer Worldwide Medicinal Chemistry
- Neuroscience and Pain Research Unit
- Great Abington
- UK
| | - J. Warmus
- Pfizer Worldwide Medicinal Chemistry
- Neuroscience and Pain Research Unit
- Groton
- USA
| | | |
Collapse
|
20
|
Luo J, Feng J, Liu S, Walters ET, Hu H. Molecular and cellular mechanisms that initiate pain and itch. Cell Mol Life Sci 2015; 72:3201-23. [PMID: 25894692 PMCID: PMC4534341 DOI: 10.1007/s00018-015-1904-4] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Revised: 03/20/2015] [Accepted: 04/07/2015] [Indexed: 12/17/2022]
Abstract
Somatosensory neurons mediate our sense of touch. They are critically involved in transducing pain and itch sensations under physiological and pathological conditions, along with other skin-resident cells. Tissue damage and inflammation can produce a localized or systemic sensitization of our senses of pain and itch, which can facilitate our detection of threats in the environment. Although acute pain and itch protect us from further damage, persistent pain and itch are debilitating. Recent exciting discoveries have significantly advanced our knowledge of the roles of membrane-bound G protein-coupled receptors and ion channels in the encoding of information leading to pain and itch sensations. This review focuses on molecular and cellular events that are important in early stages of the biological processing that culminates in our senses of pain and itch.
Collapse
Affiliation(s)
- Jialie Luo
- Department of Anesthesiology, The Center for the Study of Itch, Washington University School of Medicine, 660 S. Euclid Ave., St. Louis, MO, 63110, USA
| | | | | | | | | |
Collapse
|
21
|
Akiyama T, Nagamine M, Davoodi A, Iodi Carstens M, Cevikbas F, Steinhoff M, Carstens E. Intradermal endothelin-1 excites bombesin-responsive superficial dorsal horn neurons in the mouse. J Neurophysiol 2015; 114:2528-34. [PMID: 26311187 DOI: 10.1152/jn.00723.2015] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Accepted: 08/24/2015] [Indexed: 01/21/2023] Open
Abstract
Endothelin-1 (ET-1) has been implicated in nonhistaminergic itch. Here we used electrophysiological methods to investigate whether mouse superficial dorsal horn neurons respond to intradermal (id) injection of ET-1 and whether ET-1-sensitive neurons additionally respond to other pruritic and algesic stimuli or spinal superfusion of bombesin, a homolog of gastrin-releasing peptide (GRP) that excites spinal itch-signaling neurons. Single-unit recordings were made from lumbar dorsal horn neurons in pentobarbital-anesthetized C57BL/6 mice. We searched for units that exhibited elevated firing after id injection of ET-1 (1 μg/μl). Responsive units were further tested with mechanical stimuli, bombesin (spinal superfusion, 200 μg·ml(-1)·min(-1)), heating, cooling, and additional chemicals [histamine, chloroquine, allyl isothiocyanate (AITC), capsaicin]. Of 40 ET-1-responsive units, 48% responded to brush and pinch [wide dynamic range (WDR)] and 52% to pinch only [high threshold (HT)]. Ninety-three percent responded to noxious heat, 50% to cooling, and >70% to histamine, chloroquine, AITC, and capsaicin. Fifty-seven percent responded to bombesin, suggesting that they participate in spinal itch transmission. That most ET-1-sensitive spinal neurons also responded to pruritic and algesic stimuli is consistent with previous studies of pruritogen-responsive dorsal horn neurons. We previously hypothesized that pruritogen-sensitive neurons signal itch. The observation that ET-1 activates nociceptive neurons suggests that both itch and pain signals may be generated by ET-1 to result in simultaneous sensations of itch and pain, consistent with observations that ET-1 elicits both itch- and pain-related behaviors in animals and burning itch sensations in humans.
Collapse
Affiliation(s)
- T Akiyama
- Department of Neurobiology, Physiology, and Behavior, University of California, Davis, California
| | - M Nagamine
- Department of Neurobiology, Physiology, and Behavior, University of California, Davis, California
| | - A Davoodi
- Department of Neurobiology, Physiology, and Behavior, University of California, Davis, California
| | - M Iodi Carstens
- Department of Neurobiology, Physiology, and Behavior, University of California, Davis, California
| | - F Cevikbas
- Departments of Dermatology and Surgery, University of California, San Francisco, California; and
| | - M Steinhoff
- Department of Dermatology and Charles Institute for Translational Dermatology, University College Dublin, Dublin, Ireland
| | - E Carstens
- Department of Neurobiology, Physiology, and Behavior, University of California, Davis, California;
| |
Collapse
|
22
|
Schweintzger NA, Bambach I, Reginato E, Mayer G, Limón-Flores AY, Ullrich SE, Byrne SN, Wolf P. Mast cells are required for phototolerance induction and scratching abatement. Exp Dermatol 2015; 24:491-6. [PMID: 25776520 DOI: 10.1111/exd.12687] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/12/2015] [Indexed: 12/17/2022]
Abstract
Dermal mast cells protect the skin from inflammatory effects of ultraviolet (UV) radiation and are required for UV-induced immune suppression. We sought to determine a potential mechanistic role of mast cells in reducing the sensitivity to UV radiation (i.e. phototolerance induction) through photohardening. We administered single UV exposures as well as a chronic UV irradiation regime to mast cell-deficient Kit(W-Sh/W-Sh) mice and their controls. The chronic irradiation protocol was similar to that given for prophylaxis in certain photodermatoses in humans. Compared to controls, UV-exposed Kit(W-Sh/W-Sh) mice were more susceptible to epidermal hyperplasia and dermal oedema which was linked to blood vessel dilation. Unexpectedly, Kit(W-Sh/W-Sh) mice exhibited an excessive scratching behaviour following broadband UVB plus UVA or solar simulated UV irradiation at doses far below their minimal skin-swelling dose. Protection from this UV-induced scratching phenotype was dependent on mast cells, as engraftment of bone marrow-derived cultured mast cells abated it entirely. Kit(W-Sh/W-Sh) mice were entirely resistant to phototolerance induction by photohardening treatment. Compared to controls, these mice also showed reduced numbers of regulatory T cells and neutrophils in the skin 24 h after UV irradiation. While it is well known that mast cell-deficient mice are resistant to UV-induced immune suppression, we have discovered that they are prone to develop photo-itch and are more susceptible to UV-induced epidermal hyperplasia and skin oedema.
Collapse
Affiliation(s)
- Nina A Schweintzger
- Research Unit for Photodermatology, Department of Dermatology, Medical University of Graz, Graz, Austria.,Center for Medical Research, Medical University of Graz, Graz, Austria
| | - Isabella Bambach
- Research Unit for Photodermatology, Department of Dermatology, Medical University of Graz, Graz, Austria
| | - Eleonora Reginato
- Research Unit for Photodermatology, Department of Dermatology, Medical University of Graz, Graz, Austria.,Center for Medical Research, Medical University of Graz, Graz, Austria
| | - Gerlinde Mayer
- Research Unit for Photodermatology, Department of Dermatology, Medical University of Graz, Graz, Austria
| | - Alberto Y Limón-Flores
- Department of Immunology, UT MD Anderson Cancer Center, Houston, TX, USA.,Laboratory of Immunology, Faculty of Medicine, Universidad Autonoma de Nuevo León, Monterrey, Mexico
| | - Stephen E Ullrich
- Department of Immunology, UT MD Anderson Cancer Center, Houston, TX, USA
| | - Scott N Byrne
- Department of Immunology, UT MD Anderson Cancer Center, Houston, TX, USA.,Cellular Photoimmunology Group, Infectious Diseases and Immunology, Sydney Medical School, The Charles Perkins Centre Hub at The University of Sydney, Sydney, NSW, Australia
| | - Peter Wolf
- Research Unit for Photodermatology, Department of Dermatology, Medical University of Graz, Graz, Austria
| |
Collapse
|
23
|
Tóth BI, Szallasi A, Bíró T. Transient receptor potential channels and itch: how deep should we scratch? Handb Exp Pharmacol 2015; 226:89-133. [PMID: 25861776 DOI: 10.1007/978-3-662-44605-8_6] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Over the past 30 years, transient receptor potential (TRP) channels have evolved from a somewhat obscure observation on how fruit flies detect light to become the center of drug discovery efforts, triggering a heated debate about their potential as targets for therapeutic applications in humans. In this review, we describe our current understanding of the diverse mechanism of action of TRP channels in the itch pathway from the skin to the brain with focus on the peripheral detection of stimuli that elicit the desire to scratch and spinal itch processing and sensitization. We predict that the compelling basic research findings on TRP channels and pruritus will be translated into the development of novel, clinically useful itch medications.
Collapse
Affiliation(s)
- Balázs I Tóth
- DE-MTA "Lendület" Cellular Physiology Research Group, Department of Physiology, University of Debrecen, Debrecen, 4032, Hungary
| | | | | |
Collapse
|
24
|
Receptors, cells and circuits involved in pruritus of systemic disorders. Biochim Biophys Acta Mol Basis Dis 2014; 1842:869-92. [DOI: 10.1016/j.bbadis.2014.02.007] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Revised: 02/16/2014] [Accepted: 02/18/2014] [Indexed: 12/12/2022]
|
25
|
Kido-Nakahara M, Buddenkotte J, Kempkes C, Ikoma A, Cevikbas F, Akiyama T, Nunes F, Seeliger S, Hasdemir B, Mess C, Buhl T, Sulk M, Müller FU, Metze D, Bunnett NW, Bhargava A, Carstens E, Furue M, Steinhoff M. Neural peptidase endothelin-converting enzyme 1 regulates endothelin 1-induced pruritus. J Clin Invest 2014; 124:2683-95. [PMID: 24812665 DOI: 10.1172/jci67323] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
In humans, pruritus (itch) is a common but poorly understood symptom in numerous skin and systemic diseases. Endothelin 1 (ET-1) evokes histamine-independent pruritus in mammals through activation of its cognate G protein-coupled receptor endothelin A receptor (ETAR). Here, we have identified neural endothelin-converting enzyme 1 (ECE-1) as a key regulator of ET-1-induced pruritus and neural signaling of itch. We show here that ETAR, ET-1, and ECE-1 are expressed and colocalize in murine dorsal root ganglia (DRG) neurons and human skin nerves. In murine DRG neurons, ET-1 induced internalization of ETAR within ECE-1-containing endosomes. ECE-1 inhibition slowed ETAR recycling yet prolonged ET-1-induced activation of ERK1/2, but not p38. In a murine itch model, ET-1-induced scratching behavior was substantially augmented by pharmacological ECE-1 inhibition and abrogated by treatment with an ERK1/2 inhibitor. Using iontophoresis, we demonstrated that ET-1 is a potent, partially histamine-independent pruritogen in humans. Immunohistochemical evaluation of skin from prurigo nodularis patients confirmed an upregulation of the ET-1/ETAR/ECE-1/ERK1/2 axis in patients with chronic itch. Together, our data identify the neural peptidase ECE-1 as a negative regulator of itch on sensory nerves by directly regulating ET-1-induced pruritus in humans and mice. Furthermore, these results implicate the ET-1/ECE-1/ERK1/2 pathway as a therapeutic target to treat pruritus in humans.
Collapse
|
26
|
Lucaciu OC, Connell GP. Itch sensation through transient receptor potential channels: a systematic review and relevance to manual therapy. J Manipulative Physiol Ther 2014; 36:385-93. [PMID: 23896168 DOI: 10.1016/j.jmpt.2013.05.018] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2012] [Revised: 12/14/2012] [Accepted: 12/27/2012] [Indexed: 10/26/2022]
Abstract
OBJECTIVE Patients may present with a complaint of "itchiness" or an "odd sensation" that can be relieved by manual therapy treatment options, which demonstrates the relevance of transient receptor potential (TRP) channels. There are studies that identify the role of various TRP channels as modulators of the itch sensation; however, discrepancies in the literature exist with respect to the overall neural pathway of the itch sensation, musculoskeletal implications, and decisive therapeutic implications. The purpose of this study was to review the literature and rate the quality of published articles regarding the role of TRP channels in the itch sensation. METHODS A systematic search of relevant literature that was published in English by a peer-reviewed journal between January 2000 and June 2012 was performed in PubMed. Studies that met the predetermined inclusion criteria regarding the relationship between TRP channels and itch were identified and then evaluated for methodological quality by the Downs and Black Quality Index score system and were summarized. RESULTS Nine studies were identified that met the inclusion criteria, all of which had fair methodological quality from the perspective of the modified Downs and Black Quality Index. TRPA1, TRPM8, and TRPV1-4 were indicated as key channels responsible for the transmission of the itch sensation. TRPV1 channels convey histamine-dependent itch, and TRPA1 channels convey histamine-independent itch. Temperature, nerve growth factor, and substance-P were also described as important itch modulators. There are similarities between the neural pathways responsible for itch, pain, and temperature, which explain the ability of noxious temperature to suppress the desire to scratch. Although transcutaneous electrical nerve stimulation, innocuous vibration, and cutaneous field stimulation have demonstrated relatively weak attenuation of itch, the use of topical capsaicin, noxious heat, and noxious cold have been demonstrated as effective therapies. CONCLUSIONS The findings of this review show that studies have assessed the function of TRP channels and itch, rather than identifying the relationship between itch and effective noninvasive treatment options. Therefore, TRP channels could serve as important, complex clinical targets for manual therapists.
Collapse
Affiliation(s)
- Octavian C Lucaciu
- Department of Anatomy, Canadian Memorial Chiropractic College, Toronto, Ontario, Canada
| | | |
Collapse
|
27
|
Cevikbas F, Wang X, Akiyama T, Kempkes C, Savinko T, Antal A, Kukova G, Buhl T, Ikoma A, Buddenkotte J, Soumelis V, Feld M, Alenius H, Dillon SR, Carstens E, Homey B, Basbaum A, Steinhoff M. A sensory neuron-expressed IL-31 receptor mediates T helper cell-dependent itch: Involvement of TRPV1 and TRPA1. J Allergy Clin Immunol 2014; 133:448-60. [PMID: 24373353 PMCID: PMC3960328 DOI: 10.1016/j.jaci.2013.10.048] [Citation(s) in RCA: 484] [Impact Index Per Article: 48.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2013] [Revised: 10/18/2013] [Accepted: 10/23/2013] [Indexed: 01/16/2023]
Abstract
BACKGROUND Although the cytokine IL-31 has been implicated in inflammatory and lymphoma-associated itch, the cellular basis for its pruritic action is yet unclear. OBJECTIVE We sought to determine whether immune cell-derived IL-31 directly stimulates sensory neurons and to identify the molecular basis of IL-31-induced itch. METHODS We used immunohistochemistry and quantitative real-time PCR to determine IL-31 expression levels in mice and human subjects. Immunohistochemistry, immunofluorescence, quantitative real-time PCR, in vivo pharmacology, Western blotting, single-cell calcium imaging, and electrophysiology were used to examine the distribution, functionality, and cellular basis of the neuronal IL-31 receptor α in mice and human subjects. RESULTS Among all immune and resident skin cells examined, IL-31 was predominantly produced by TH2 and, to a significantly lesser extent, mature dendritic cells. Cutaneous and intrathecal injections of IL-31 evoked intense itch, and its concentrations increased significantly in murine atopy-like dermatitis skin. Both human and mouse dorsal root ganglia neurons express IL-31RA, largely in neurons that coexpress transient receptor potential cation channel vanilloid subtype 1 (TRPV1). IL-31-induced itch was significantly reduced in TRPV1-deficient and transient receptor channel potential cation channel ankyrin subtype 1 (TRPA1)-deficient mice but not in c-kit or proteinase-activated receptor 2 mice. In cultured primary sensory neurons IL-31 triggered Ca(2+) release and extracellular signal-regulated kinase 1/2 phosphorylation, inhibition of which blocked IL-31 signaling in vitro and reduced IL-31-induced scratching in vivo. CONCLUSION IL-31RA is a functional receptor expressed by a small subpopulation of IL-31RA(+)/TRPV1(+)/TRPA1(+) neurons and is a critical neuroimmune link between TH2 cells and sensory nerves for the generation of T cell-mediated itch. Thus targeting neuronal IL-31RA might be effective in the management of TH2-mediated itch, including atopic dermatitis and cutaneous T-cell lymphoma.
Collapse
Affiliation(s)
- Ferda Cevikbas
- Departments of Dermatology and Surgery, University of California, San Francisco, San Francisco, Calif; Department of Dermatology, University Hospital Düsseldorf, Düsseldorf, Germany
| | - Xidao Wang
- Department of Anatomy and the W.M. Keck Foundation Center for Integrative Neuroscience, University of California, San Francisco, San Francisco, Calif
| | - Tasuku Akiyama
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, Calif
| | - Cordula Kempkes
- Departments of Dermatology and Surgery, University of California, San Francisco, San Francisco, Calif
| | - Terhi Savinko
- Unit of Toxicology, Finnish Institute of Occupational Health, Helsinki, Finland
| | - Attila Antal
- Department of Dermatology, University Hospital Düsseldorf, Düsseldorf, Germany
| | - Gabriela Kukova
- Department of Dermatology, University Hospital Düsseldorf, Düsseldorf, Germany
| | - Timo Buhl
- Departments of Dermatology and Surgery, University of California, San Francisco, San Francisco, Calif
| | - Akihiko Ikoma
- Departments of Dermatology and Surgery, University of California, San Francisco, San Francisco, Calif
| | - Joerg Buddenkotte
- Department of Dermatology, University Hospital Münster, Muenster, Germany
| | | | - Micha Feld
- Department of Dermatology, University Hospital Düsseldorf, Düsseldorf, Germany
| | - Harri Alenius
- Unit of Toxicology, Finnish Institute of Occupational Health, Helsinki, Finland
| | - Stacey R Dillon
- ZymoGenetics (a Bristol-Myers Squibb Company), Seattle, Wash
| | - Earl Carstens
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, Calif
| | - Bernhard Homey
- Department of Dermatology, University Hospital Düsseldorf, Düsseldorf, Germany.
| | - Allan Basbaum
- Department of Anatomy and the W.M. Keck Foundation Center for Integrative Neuroscience, University of California, San Francisco, San Francisco, Calif.
| | - Martin Steinhoff
- Departments of Dermatology and Surgery, University of California, San Francisco, San Francisco, Calif; Department of Dermatology, University Hospital Düsseldorf, Düsseldorf, Germany.
| |
Collapse
|
28
|
Bautista DM, Wilson SR, Hoon MA. Why we scratch an itch: the molecules, cells and circuits of itch. Nat Neurosci 2014; 17:175-82. [PMID: 24473265 PMCID: PMC4364402 DOI: 10.1038/nn.3619] [Citation(s) in RCA: 235] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Accepted: 12/03/2013] [Indexed: 12/17/2022]
Abstract
Itch is described as an irritating sensation that triggers a desire to scratch. However, this definition hardly seems fitting for the millions of people who suffer from intractable itch. Indeed, the Buddhist philosopher Nāgārjuna more aptly stated, "There is pleasure when an itch is scratched. But to be without an itch is more pleasurable still." Chronic itch is widespread and very difficult to treat. In this review we focus on the molecules, cells and circuits in the peripheral and central nervous systems that drive acute and chronic itch transmission. Understanding the itch circuitry is critical to developing new therapies for this intractable disease.
Collapse
Affiliation(s)
- Diana M Bautista
- 1] Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, California, USA. [2] Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, California, USA
| | - Sarah R Wilson
- 1] Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, California, USA. [2] Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, California, USA
| | - Mark A Hoon
- Molecular Genetics Unit, Laboratory of Sensory Biology, National Institute of Dental and Craniofacial Research/NIH, Bethesda, Maryland, USA
| |
Collapse
|
29
|
Abstract
While considerable effort has been made to investigate the neural mechanisms of pain, much less effort has been devoted to itch, at least until recently. However, itch is now gaining increasing recognition as a widespread and costly medical and socioeconomic issue. This is accompanied by increasing interest in the underlying neural mechanisms of itch, which has become a vibrant and rapidly-advancing field of research. The goal of the present forefront review is to describe the recent progress that has been made in our understanding of itch mechanisms.
Collapse
Affiliation(s)
- Tasuku Akiyama
- University of California, Davis, Department of Neurobiology, Physiology & Behavior, 1 Shields Avenue, Davis, CA 95616, United States
| | | |
Collapse
|
30
|
Targeting TRP channels for pain relief. Eur J Pharmacol 2013; 716:61-76. [DOI: 10.1016/j.ejphar.2013.03.003] [Citation(s) in RCA: 227] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2012] [Accepted: 03/04/2013] [Indexed: 11/23/2022]
|
31
|
Abstract
INTRODUCTION Chronic pruritus (CP), defined as itch lasting for > 6 weeks, is a burdensome symptom of several different diseases, dermatological and systemic, with a high negative impact on the quality of life of patients. Given the manifold aetiologies of CP, therapy is often difficult. In recent years, however, novel substances have been developed for treatment of certain CP entities and identified targets. AREAS COVERED In this review, the authors present a survey of targets currently believed to be promising (H4R, IL-31, MOR, KOR, GRPR, NGF, NK-1R, TRP channels) and related investigational drugs that are in the preclinical or clinical stage of development. Some substances have already undergone clinical testing, but only one of them (nalfurafine) has been licensed so far. Many of them are most likely to exert their effects on the skin and interfere there with the cutaneous neurobiology of CP. EXPERT OPINION Currently, the most promising candidates for new therapeutic agents in CP are neurokinin-1 receptor antagonists and substances targeting the kappa- or mu-opioid receptor, or both. They have the potential to target the neuronal pathway of CP and are thus of interest for several CP entities. The goal for the coming years is to validate these concepts and move forward in developing new drugs for the therapy of CP.
Collapse
Affiliation(s)
- Heike Benecke
- University Medicine Göttingen, Center Nanoscale Microscopy and Molecular Physiology of the Brain, Humboldtallee 23, 37073 Göttingen, Germany
| | | | | |
Collapse
|
32
|
Liu B, Escalera J, Balakrishna S, Fan L, Caceres AI, Robinson E, Sui A, McKay MC, McAlexander MA, Herrick CA, Jordt SE. TRPA1 controls inflammation and pruritogen responses in allergic contact dermatitis. FASEB J 2013; 27:3549-63. [PMID: 23722916 DOI: 10.1096/fj.13-229948] [Citation(s) in RCA: 167] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Allergic contact dermatitis is a common skin disease associated with inflammation and persistent pruritus. Transient receptor potential (TRP) ion channels in skin-innervating sensory neurons mediate acute inflammatory and pruritic responses following exogenous stimulation and may contribute to allergic responses. Genetic ablation or pharmacological inhibition of TRPA1, but not TRPV1, inhibited skin edema, keratinocyte hyperplasia, nerve growth, leukocyte infiltration, and antihistamine-resistant scratching behavior in mice exposed to the haptens, oxazolone and urushiol, the contact allergen of poison ivy. Hapten-challenged skin of TRPA1-deficient mice contained diminished levels of inflammatory cytokines, nerve growth factor, and endogenous pruritogens, such as substance P (SP) and serotonin. TRPA1-deficient sensory neurons were defective in SP signaling, and SP-induced scratching behavior was abolished in Trpa1(-/-) mice. SP receptor antagonists, such as aprepitant inhibited both hapten-induced cutaneous inflammation and scratching behavior. These findings support a central role for TRPA1 and SP in the integration of immune and neuronal mechanisms leading to chronic inflammatory responses and pruritus associated with contact dermatitis.
Collapse
Affiliation(s)
- Boyi Liu
- Department of Pharmacology, Yale School of Medicine, 333 Cedar St., New Haven, CT 06510, USA
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
33
|
Staurengo-Ferrari L, Mizokami SS, Silva JJ, da Silva FON, Sousa EHS, da França LG, Matuoka ML, Georgetti SR, Baracat MM, Casagrande R, Pavanelli WR, Verri WA. The ruthenium NO donor, [Ru(bpy)2(NO)SO3](PF6), inhibits inflammatory pain: involvement of TRPV1 and cGMP/PKG/ATP-sensitive potassium channel signaling pathway. Pharmacol Biochem Behav 2013; 105:157-65. [PMID: 23470198 DOI: 10.1016/j.pbb.2013.02.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/03/2012] [Revised: 02/11/2013] [Accepted: 02/13/2013] [Indexed: 10/27/2022]
Abstract
The activation of nitric oxide (NO) production is an analgesic mechanism shared by drugs such as morphine and diclofenac. Therefore, the controlled release of low amounts of NO seems to be a promising analgesic approach. In the present study, the antinociceptive effect of the ruthenium NO donor [Ru(bpy)2(NO)SO3](PF6) (complex I) was investigated. It was observed that complex I inhibited in a dose (0.3-10mg/kg)-dependent manner the acetic acid-induced writhing response. At the dose of 1mg/kg, complex I inhibited the phenyl-p-benzoquinone-induced writhing response and formalin- and complete Freund's adjuvant-induced licking and flinch responses. Additionally, complex I also inhibited transient receptor potential cation channel subfamily V member 1 (TRPV1)-dependent overt pain-like behavior induced by capsaicin. Complex I also inhibited the carrageenin-induced mechanical hyperalgesia and increase of myeloperoxidase activity (MPO) in paw skin samples. The inhibitory effect of complex I in the carrageenin-induced hyperalgesia, MPO activity and formalin was prevented by the treatment with ODQ, KT5823 and glybenclamide, indicating that complex I inhibits inflammatory hyperalgesia by activating the cGMP/PKG/ATP-sensitive potassium channel signaling pathway. The present study demonstrates the efficacy of a novel ruthenium NO donor and its analgesic mechanisms.
Collapse
Affiliation(s)
- Larissa Staurengo-Ferrari
- Departamento de Patologia, Centro de Ciências Biológicas, Universidade Estadual de Londrina, Rod. Celso Garcia Cid KM480 PR445, CEP 86051-990, Cx Postal 6001, Londrina, Paraná, Brazil
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
34
|
Gomes LO, Hara DB, Rae GA. Endothelin-1 induces itch and pain in the mouse cheek model. Life Sci 2012; 91:628-33. [DOI: 10.1016/j.lfs.2012.03.020] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2011] [Revised: 03/05/2012] [Accepted: 03/08/2012] [Indexed: 11/29/2022]
|
35
|
Ji W, Liang J, Zhang Z. Endothelin B receptors exert antipruritic effects via peripheral κ-opioid receptors. Exp Ther Med 2012. [PMID: 23181126 PMCID: PMC3503748 DOI: 10.3892/etm.2012.624] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Endothelin B receptor agonists exert antipruritic effects on itching induced via endothelin-1 (ET-1) and compound 48/80. Peripheral µ- and κ-opioid receptors (MORs and KORs, respectively) are reported to be involved in the anti-nociceptive properties triggered by ETB agonists. Therefore, we investigated the role of peripheral opioid receptors in the scratching response induced by ET-1. ETA and ETB antagonists and non-selective and selective opioid receptor antagonists were co-injected with ET-1 in the neck of mice and the number of scratching bouts was counted. Pretreatment with systemically administered naloxone significantly reduced the number of scratches, while co-injection of naloxone substantially augmented the effect of ET-1. Co-injection of nor-Binaltorphimine (nor-BNI), a KOR antagonist, significantly increased the number of scratches induced by ET-1. However, CTOP (a MOR antagonist) and naltrindole [a δ-opioid receptor (DOR) antagonist] did not alter the scratching response elicited by ET-1. These results indicate that peripheral KORs mediate the antipruritic effect of endothelin B receptor activation.
Collapse
Affiliation(s)
- Wenjin Ji
- Departments of Anesthesiology, and ; Postgraduate Institute, Southern Medical University, Guangzhou, P.R. China
| | | | | |
Collapse
|
36
|
Liang J, He Y, Ji W. Bradykinin-evoked scratching responses in complete Freund's adjuvant-inflamed skin through activation of B1 receptor. Exp Biol Med (Maywood) 2012; 237:318-26. [PMID: 22378823 DOI: 10.1258/ebm.2011.011308] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Capsaicin, a potent algogen, induces an itch-related behavior in the presence of inflammation. In this study, we tested whether bradykinin (BK) can evoke a similar response and investigated the potential mechanisms involved in this process. Local inflammation was induced by intradermal injection of complete Freund's adjuvant (CFA) into the back of the neck, left hind foot or left cheek of male C57BL/6J mice. BK was then injected intradermally into the same area on indicated days. Four days after CFA inflammation, BK treatment evoked scratching responses in a time- and dose-dependent manner. For BK receptor antagonist treatment, inflamed-mice were either given an intraperitoneal injection of B(1) receptor (B(1)R) or B(2) receptor (B(2)R) antagonist 30 min prior to BK administration, or an intradermal co-injection of antagonist and BK into the inflamed area. Our results indicate that B(1)R and B(2)R act in an opposite fashion during this process, as pretreatment with B(1)R antagonist by intraperitoneal injection significantly reduced BK-induced scratching behavior, whereas B(2)R antagonist treatment dramatically increased scratching behavior. Moreover, combined injection of BK and B(2)R antagonist enhanced BK-induced scratching activity in CFA-inflamed mice. In addition, pretreatment or co-injection with B(2)R antagonist dramatically reduced the pain-related licking behavior induced by BK injection. The data suggest that BK-induced scratching responses in CFA-inflamed mouse skin occur via activation of B(1)R. Furthermore, B(1) and B(2) receptors play different roles in modulating BK-induced itch-related behavior in CFA-inflamed mice.
Collapse
Affiliation(s)
- Jiexian Liang
- Department of Anesthesiology, Guangdong Cardiovascular Institute, Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangzhou 510080, China
| | | | | |
Collapse
|
37
|
|
38
|
Current World Literature. Curr Opin Nephrol Hypertens 2012; 21:106-18. [DOI: 10.1097/mnh.0b013e32834ee42b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
39
|
Klein A, Carstens MI, Carstens E. Facial injections of pruritogens or algogens elicit distinct behavior responses in rats and excite overlapping populations of primary sensory and trigeminal subnucleus caudalis neurons. J Neurophysiol 2011; 106:1078-88. [PMID: 21653727 DOI: 10.1152/jn.00302.2011] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In the present study, we investigated whether intradermal cheek injection of pruritogens or algogens differentially elicits hindlimb scratches or forelimb wipes in Sprague-Dawley rats, as recently reported in mice. We also investigated responses of primary sensory trigeminal ganglion (TG) and dorsal root ganglion (DRG) cells, as well as second-order neurons in trigeminal subnucleus caudalis (Vc), to pruritic and algesic stimuli. 5-HT was the most effective chemical to elicit dose-dependent bouts of hindlimb scratches directed to the cheek, with significantly less forelimb wiping, consistent with itch. Chloroquine also elicited significant scratching but not wiping. Allyl isothiocyanate (AITC; mustard oil) elicited dose-dependent wiping with no significant scratching. Capsaicin elicited equivalent numbers of scratch bouts and wipes, suggesting a mixed itch and pain sensation. By calcium imaging, ∼ 6% of cultured TG and DRG cells responded to 5-HT. The majority of 5-HT-sensitive cells also responded to chloroquine, AITC, and/or capsaicin, and one-third responded to histamine. Using a chemical search strategy, we identified single units in Vc that responded to intradermal cheek injection of 5-HT. Most were wide dynamic range (WDR) or nociceptive specific (NS), and a few were mechanically insensitive. The large majority additionally responded to AITC and/or capsaicin and thus were not pruritogen selective. These results suggest that primary and second-order neurons responsive to pruritogens and algogens may utilize a population coding mechanism to distinguish between itch and pain, sensations that are behaviorally manifested by distinct hindlimb scratching and forelimb wiping responses.
Collapse
Affiliation(s)
- Amanda Klein
- Department of Neurobiology, Physiology, and Behavior, University of California, Davis, 1 Shields Ave., Davis, CA 95616, USA
| | | | | |
Collapse
|