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Xu JF, Liu L, Liu Y, Lu KX, Zhang J, Zhu YJ, Fang F, Dou YN. Spinal Nmur2-positive Neurons Play a Crucial Role in Mechanical Itch. THE JOURNAL OF PAIN 2024; 25:104504. [PMID: 38442838 DOI: 10.1016/j.jpain.2024.02.018] [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: 07/06/2023] [Revised: 02/23/2024] [Accepted: 02/29/2024] [Indexed: 03/07/2024]
Abstract
The dorsal spinal cord is crucial for the transmission and modulation of multiple somatosensory modalities, such as itch, pain, and touch. Despite being essential for the well-being and survival of an individual, itch and pain, in their chronic forms, have increasingly been recognized as clinical problems. Although considerable progress has been made in our understanding of the neurochemical processing of nociceptive and chemical itch sensations, the neural substrate that is crucial for mechanical itch processing is still unclear. Here, using genetic and functional manipulation, we identified a population of spinal neurons expressing neuromedin U receptor 2 (Nmur2+) as critical elements for mechanical itch. We found that spinal Nmur2+ neurons are predominantly excitatory neurons, and are enriched in the superficial laminae of the dorsal horn. Pharmacogenetic activation of cervical spinal Nmur2+ neurons evoked scratching behavior. Conversely, the ablation of these neurons using a caspase-3-based method decreased von Frey filament-induced scratching behavior without affecting responses to other somatosensory modalities. Similarly, suppressing the excitability of cervical spinal Nmur2+ neurons via the overexpression of functional Kir2.1 potassium channels reduced scratching in response to innocuous mechanical stimuli, but not to pruritogen application. At the lumbar level, pharmacogenetic activation of these neurons evoked licking and lifting behaviors. However, ablating these neurons did not affect the behavior associated with acute pain. Thus, these results revealed the crucial role of spinal Nmur2+ neurons in mechanical itch. Our study provides important insights into the neural basis of mechanical itch, paving the way for developing novel therapies for chronic itch. PERSPECTIVE: Excitatory Nmur2+ neurons in the superficial dorsal spinal cord are essential for mechanical but not chemical itch information processing. These spinal Nmur2+ neurons represent a potential cellular target for future therapeutic interventions against chronic itch. Spinal and supraspinal Nmur2+ neurons may play different roles in pain signal processing.
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Affiliation(s)
- Jun-Feng Xu
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science & Intelligence Technology, Chinese Academy of Sciences, Shanghai, China
| | - Lian Liu
- Department of Endocrinology and Metabolic Diseases, Shanghai General Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Yuan Liu
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science & Intelligence Technology, Chinese Academy of Sciences, Shanghai, China; School of Life Science and Technology, ShanghaiTech University, Shanghai, China; Lingang Laboratory, Shanghai, China
| | - Ke-Xing Lu
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science & Intelligence Technology, Chinese Academy of Sciences, Shanghai, China
| | - Jun Zhang
- Department of Anesthesiology, Daping Hospital, Army Medical University, Chongqing, China
| | - Yan-Jing Zhu
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science & Intelligence Technology, Chinese Academy of Sciences, Shanghai, China
| | - Fang Fang
- Department of Endocrinology and Metabolic Diseases, Shanghai General Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Yan-Nong Dou
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science & Intelligence Technology, Chinese Academy of Sciences, Shanghai, China
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Chu DK, Schneider L, Asiniwasis RN, Boguniewicz M, De Benedetto A, Ellison K, Frazier WT, Greenhawt M, Huynh J, Kim E, LeBovidge J, Lind ML, Lio P, Martin SA, O'Brien M, Ong PY, Silverberg JI, Spergel JM, Wang J, Wheeler KE, Guyatt GH, Capozza K, Begolka WS, Chu AWL, Zhao IX, Chen L, Oykhman P, Bakaa L, Golden D, Shaker M, Bernstein JA, Greenhawt M, Horner CC, Lieberman J, Stukus D, Rank MA, Wang J, Ellis A, Abrams E, Ledford D, Chu DK. Atopic dermatitis (eczema) guidelines: 2023 American Academy of Allergy, Asthma and Immunology/American College of Allergy, Asthma and Immunology Joint Task Force on Practice Parameters GRADE- and Institute of Medicine-based recommendations. Ann Allergy Asthma Immunol 2024; 132:274-312. [PMID: 38108679 DOI: 10.1016/j.anai.2023.11.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 11/08/2023] [Accepted: 11/09/2023] [Indexed: 12/19/2023]
Abstract
BACKGROUND Guidance addressing atopic dermatitis (AD) management, last issued in 2012 by the American Academy of Allergy, Asthma and Immunology/American College of Allergy, Asthma and Immunology Joint Task Force, requires updating as a result of new treatments and improved guideline and evidence synthesis methodology. OBJECTIVE To produce evidence-based guidelines that support patients, clinicians, and other decision-makers in the optimal treatment of AD. METHODS A multidisciplinary guideline panel consisting of patients and caregivers, AD experts (dermatology and allergy/immunology), primary care practitioners (family medicine, pediatrics, internal medicine), and allied health professionals (psychology, pharmacy, nursing) convened, prioritized equity, diversity, and inclusiveness, and implemented management strategies to minimize influence of conflicts of interest. The Evidence in Allergy Group supported guideline development by performing systematic evidence reviews, facilitating guideline processes, and holding focus groups with patient and family partners. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach informed rating the certainty of evidence and strength of recommendations. Evidence-to-decision frameworks, subjected to public comment, translated evidence to recommendations using trustworthy guideline principles. RESULTS The panel agreed on 25 recommendations to gain and maintain control of AD for patients with mild, moderate, and severe AD. The eAppendix provides practical information and implementation considerations in 1-2 page patient-friendly handouts. CONCLUSION These evidence-based recommendations address optimal use of (1) topical treatments (barrier moisturization devices, corticosteroids, calcineurin inhibitors, PDE4 inhibitors [crisaborole], topical JAK inhibitors, occlusive [wet wrap] therapy, adjunctive antimicrobials, application frequency, maintenance therapy), (2) dilute bleach baths, (3) dietary avoidance/elimination, (4) allergen immunotherapy, and (5) systemic treatments (biologics/monoclonal antibodies, small molecule immunosuppressants [cyclosporine, methotrexate, azathioprine, mycophenolate, JAK inhibitors], and systemic corticosteroids) and UV phototherapy (light therapy).
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Affiliation(s)
- Derek K Chu
- Departments of Medicine and Health Research Methods, Evidence & Impact, McMaster University, Hamilton, Canada; Evidence in Allergy Group, McMaster University and The Research Institute of St. Joe's Hamilton, Hamilton, Canada.
| | - Lynda Schneider
- Division of Immunology, Boston Children's Hospital, Boston, Massachusetts.
| | | | - Mark Boguniewicz
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, Colorado; Division of Pediatric Allergy and Clinical Immunology, National Jewish Health, Denver, Colorado
| | - Anna De Benedetto
- Department of Dermatology, University of Rochester Medical Center, Rochester, New York
| | | | - Winfred T Frazier
- Department of Family Medicine, UPMC St. Margaret, Pittsburgh, Pennsylvania
| | - Matthew Greenhawt
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, Colorado; Section of Allergy and Immunology, Children's Hospital Colorado, Aurora, Colorado
| | - Joey Huynh
- Sepulveda VA Medical Center, North Hills, California
| | | | - Jennifer LeBovidge
- Division of Immunology, Boston Children's Hospital, Boston, Massachusetts; Harvard Medical School, Boston, Massachusetts
| | - Mary Laura Lind
- School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, Arizona
| | - Peter Lio
- Department of Dermatology, Northwestern University Feinberg School of Medicine, Chicago, Illinois; Department of Pediatrics, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Stephen A Martin
- University of Massachusetts Chan Medical School, Worcester, Massachusetts
| | - Monica O'Brien
- Tufts University School of Medicine, Boston, Massachusetts
| | - Peck Y Ong
- Division of Clinical Immunology and Allergy, Children's Hospital Los Angeles, Los Angeles, California; Department of Pediatrics, USC Keck School of Medicine, Los Angeles, California
| | - Jonathan I Silverberg
- Department of Dermatology, The George Washington University School of Medicine and Health Sciences, Washington, District of Columbia
| | - Jonathan M Spergel
- Department of Pediatrics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania; Division of Allergy and Immunology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Julie Wang
- Division of Pediatric Allergy and Immunology, Department of Pediatrics, Icahn School of Medicine at Mount Sinai, New York City, New York
| | - Kathryn E Wheeler
- Department of Pediatrics, University of Florida, Gainesville, Florida
| | - Gordon H Guyatt
- Departments of Medicine and Health Research Methods, Evidence & Impact, McMaster University, Hamilton, Canada; Evidence in Allergy Group, McMaster University and The Research Institute of St. Joe's Hamilton, Hamilton, Canada
| | - Korey Capozza
- Global Parents for Eczema Research, Santa Barbara, California
| | | | - Alexandro W L Chu
- Departments of Medicine and Health Research Methods, Evidence & Impact, McMaster University, Hamilton, Canada; Evidence in Allergy Group, McMaster University and The Research Institute of St. Joe's Hamilton, Hamilton, Canada
| | - Irene X Zhao
- Departments of Medicine and Health Research Methods, Evidence & Impact, McMaster University, Hamilton, Canada; Evidence in Allergy Group, McMaster University and The Research Institute of St. Joe's Hamilton, Hamilton, Canada
| | - Lina Chen
- Departments of Medicine and Health Research Methods, Evidence & Impact, McMaster University, Hamilton, Canada; Evidence in Allergy Group, McMaster University and The Research Institute of St. Joe's Hamilton, Hamilton, Canada
| | - Paul Oykhman
- Departments of Medicine and Health Research Methods, Evidence & Impact, McMaster University, Hamilton, Canada; Evidence in Allergy Group, McMaster University and The Research Institute of St. Joe's Hamilton, Hamilton, Canada
| | - Layla Bakaa
- Departments of Medicine and Health Research Methods, Evidence & Impact, McMaster University, Hamilton, Canada; Evidence in Allergy Group, McMaster University and The Research Institute of St. Joe's Hamilton, Hamilton, Canada
| | - David Golden
- Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Marcus Shaker
- Dartmouth Geisel School of Medicine and Dartmouth Hitchcock Medical Center, Section of Allergy, Lebanon, New Hampshire
| | | | - Matthew Greenhawt
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, Colorado; Section of Allergy and Immunology, Children's Hospital Colorado, Aurora, Colorado
| | - Caroline C Horner
- Division of Allergy and Pulmonary Medicine, Department of Pediatrics, Washington University School of Medicine, St Louis, Missouri
| | - Jay Lieberman
- University of Tennessee Health Science Center and LeBonheur Children's Hospital, Memphis, Tennessee
| | - David Stukus
- Nationwide Children's Hospital and Ohio State University College of Medicine, Columbus, Ohio
| | - Matthew A Rank
- Mayo Clinic in Arizona and Phoenix Children's Hospital, Scottsdale and Phoenix, Arizona
| | - Julie Wang
- Division of Pediatric Allergy and Immunology, Department of Pediatrics, Icahn School of Medicine at Mount Sinai, New York City, New York
| | - Anne Ellis
- Division of Allergy and Immunology, Department of Medicine, Queen's University, Kingston, Ontario, Canada
| | - Elissa Abrams
- Section of Allergy and Clinical Immunology, Department of Pediatrics, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Dennis Ledford
- Morsani College of Medicine, University of South Florida and James A. Haley Veterans' Affairs Hospital, Tampa, Florida
| | - Derek K Chu
- Departments of Medicine and Health Research Methods, Evidence & Impact, McMaster University, Hamilton, Canada; Evidence in Allergy Group, McMaster University and The Research Institute of St. Joe's Hamilton, Hamilton, Canada
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