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Abstract
Interactions between the immune system and the nervous system have been described mostly in the context of diseases. More recent studies have begun to reveal how certain immune cell-derived soluble effectors, the cytokines, can influence host behaviour even in the absence of infection. In this Review, we contemplate how the immune system shapes nervous system function and how it controls the manifestation of host behaviour. Interactions between these two highly complex systems are discussed here also in the context of evolution, as both may have evolved to maximize an organism's ability to respond to environmental threats in order to survive. We describe how the immune system relays information to the nervous system and how cytokine signalling occurs in neurons. We also speculate on how the brain may be hardwired to receive and process information from the immune system. Finally, we propose a unified theory depicting a co-evolution of the immune system and host behaviour in response to the evolutionary pressure of pathogens.
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Liu F, Shen X, Su S, Cui H, Fang Y, Wang T, Zhang L, Huang Y, Ma C. Fcγ Receptor I-Coupled Signaling in Peripheral Nociceptors Mediates Joint Pain in a Rat Model of Rheumatoid Arthritis. Arthritis Rheumatol 2020; 72:1668-1678. [PMID: 32510872 DOI: 10.1002/art.41386] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 05/01/2020] [Accepted: 05/27/2020] [Indexed: 12/12/2022]
Abstract
OBJECTIVE Rheumatoid arthritis (RA) is often accompanied by joint pain and inflammation. Previous studies have demonstrated that functional Fcγ receptor I (FcγRI) is expressed in dorsal root ganglion (DRG) neurons and might contribute to pain in rodent models of antigen-induced arthritis (AIA). This study was undertaken to elucidate the roles of nociceptive neuronal FcγRI-coupled signaling in the development of joint pain in AIA. METHODS RNA sequencing was used to investigate the transcriptome profile changes in the DRG in a rat model of AIA. A primary sensory neuron-specific Fcgr1a conditional-knockout (CKO) rat was established by crossing rats carrying a loxP-flanked Fcgr1a with a Pirt-specific Cre line. Behavioral, morphologic, and molecular studies were conducted to evaluate the differences between wild-type (WT) and CKO rats after AIA. RESULTS We first showed that AIA induced a transcriptome profile change in the DRG, involving a number of key proteins downstream of the FcγRI-related signaling pathway. Compared to the WT rats, both the IgG immune complex-induced acute pain and AIA-induced pain were alleviated in CKO rats. Moreover, the AIA-induced activation of FcγRI-related signaling in DRGs was significantly reduced in CKO rats. In addition, CKO rats showed attenuated joint swelling after AIA. CONCLUSION These results indicate that activation of FcγRI-coupled signaling in DRG neurons plays an important role in the development of joint pain in AIA. Our findings may provide novel insights into the interactions between the peripheral nervous system and the immune system in pathologic conditions and might suggest potential biotargets for the treatment of pain in RA.
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Affiliation(s)
- Fan Liu
- Institute of Basic Medical Sciences, Neuroscience Center, Chinese Academy of Medical Sciences and Joint Laboratory of Anesthesia and Pain, Peking Union Medical College, Beijing, China
| | - Xinhua Shen
- Institute of Basic Medical Sciences, Neuroscience Center, Chinese Academy of Medical Sciences, and Peking Union Medical College, Beijing, China
| | - Si Su
- Institute of Basic Medical Sciences, Neuroscience Center, Chinese Academy of Medical Sciences and Joint Laboratory of Anesthesia and Pain, Peking Union Medical College, Beijing, China
| | - Huan Cui
- Institute of Basic Medical Sciences, Neuroscience Center, Chinese Academy of Medical Sciences and Joint Laboratory of Anesthesia and Pain, Peking Union Medical College, Beijing, China
| | - Yehong Fang
- Institute of Basic Medical Sciences, Neuroscience Center, Chinese Academy of Medical Sciences and Joint Laboratory of Anesthesia and Pain, Peking Union Medical College, Beijing, China
| | - Tao Wang
- Institute of Basic Medical Sciences, Neuroscience Center, Chinese Academy of Medical Sciences and Joint Laboratory of Anesthesia and Pain, Peking Union Medical College, Beijing, China
| | - Lianfeng Zhang
- Key Laboratory of Human Disease Comparative Medicine, Ministry of Health, Institute of Laboratory Animal Science, Chinese Academy of Medical Sciences and Comparative Medical Center, and Peking Union Medical College, Beijing, China
| | - Yuguang Huang
- Joint Laboratory of Anesthesia and Pain, Peking Union Medical College, Peking Union Medical College Hospital, and Chinese Academy of Medical Sciences, Beijing, China
| | - Chao Ma
- Institute of Basic Medical Sciences, Neuroscience Center, Chinese Academy of Medical Sciences and Joint Laboratory of Anesthesia and Pain, Peking Union Medical College, Beijing, China
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Changes in inflammatory plasma proteins from patients with chronic pain associated with treatment in an interdisciplinary multimodal rehabilitation program – an explorative multivariate pilot study. Scand J Pain 2019; 20:125-138. [DOI: 10.1515/sjpain-2019-0088] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Accepted: 09/10/2019] [Indexed: 01/04/2023]
Abstract
Abstract
It has been suggested that alterations in inflammation molecules maintain chronic pain although little is known about how these factors influence homeostatic and inflammatory events in common chronic pain conditions. Nonpharmacological interventions might be associated with alterations in inflammation markers in blood. This study of patients with chronic pain investigates whether an interdisciplinary multimodal rehabilitation program (IMMRP) was associated with significant alterations in the plasma pattern of 68 cytokines/chemokines 1 year after rehabilitation and whether such changes were associated with clinical changes. Blood samples and self-reports of pain, psychological distress, and physical activity of 25 complex chronic pain patients were collected pre-IMMRP and at 12-month follow-up. Analyses of inflammatory proteins (cytokines/chemokines/growth factors) were performed directly in plasma using the multiplex immunoassay technology Meso Scale Discovery. This explorative pilot study found that 12 substances, mainly pro-inflammatory, decreased after IMMRP. In two other relatively small IMMRP studies, four of these proinflammatory markers were also associated with decreases. The pattern of cytokines/chemokines pre-IMMRP was associated with changes in psychological distress but not with pain or physical activity. The present study cannot impute cause and effect. These results together with the results of the two previous IMMRP studies suggest that there is a need for larger and more strictly controlled studies of IMMRP with respect to inflammatory markers in blood. Such studies need to consider responders/non-responders, additional therapies, involved pain mechanisms and diagnoses. This and the two other studies open up for developing biologically measurable outcomes from plasma. Such biomarkers will be an important tool for further development of IMMRP and possibly other treatments for patients w ith chronic pain.
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UCHL1/PGP 9.5 Dynamic in Neuro-Immune-Cutaneous Milieu: Focusing on Axonal Nerve Terminals and Epidermal Keratinocytes in Psoriatic Itch. BIOMED RESEARCH INTERNATIONAL 2018; 2018:7489316. [PMID: 30148172 PMCID: PMC6083486 DOI: 10.1155/2018/7489316] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Revised: 05/28/2018] [Accepted: 06/07/2018] [Indexed: 01/03/2023]
Abstract
Psoriasis is an immunogenetic skin disease manifesting as plaque lesions on the skin. Patients with psoriasis frequently suffer from itch, an unpleasant sensation causing a desire to scratch. Psoriatic itch is mainly transmitted by unmyelinated C-fibers; however, the exact molecular mechanism of psoriatic itch is still unexplained. Protein gene product 9.5 (PGP 9.5) is a panneurological marker commonly used for analysis of peripheral peptidergic and nonpeptidergic nerves and identification of cutaneous neuro-immune-endocrine cells. However, some studies suggested that nonneuronal cells, like keratinocytes, may also express PGP 9.5. This phenomenon might be linked with impaired axonal transport, keratinocyte injury, or dysfunctions of neuro-immune-cutaneous connections. The aim of this study was to analyze the expression of PGP 9.5 in psoriatic skin. We observed significantly altered density of PGP 9.5-positive axonal nerve terminals in pruritic lesional (p=0.04) and nonlesional psoriatic skin (p>0.001) compared with controls. In contrast, no significant differences were observed between psoriatic skin without itch and controls. Furthermore, PGP 9.5 expression by suprabasal keratinocytes (SBKs) was significantly increased in itchy skin lesions (p=0.007) compared to skin without itch, and a positive correlation was observed between PGP 9.5 expression and itch intensity (r=0.64; p=0.02). Our findings indicate changes in peripheral innervations and psoriatic keratinocytes, which may influence neuro-immune-cutaneous homeostasis and modulate itch transmission.
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Jiang H, Shen X, Chen Z, Liu F, Wang T, Xie Y, Ma C. Nociceptive neuronal Fc-gamma receptor I is involved in IgG immune complex induced pain in the rat. Brain Behav Immun 2017; 62:351-361. [PMID: 28263785 DOI: 10.1016/j.bbi.2017.03.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Revised: 02/13/2017] [Accepted: 03/01/2017] [Indexed: 02/07/2023] Open
Abstract
Antigen-specific immune diseases such as rheumatoid arthritis are often accompanied by pain and hyperalgesia. Our previous studies have demonstrated that Fc-gamma-receptor type I (FcγRI) is expressed in a subpopulation of rat dorsal root ganglion (DRG) neurons and can be directly activated by IgG immune complex (IgG-IC). In this study we investigated whether neuronal FcγRI contributes to antigen-specific pain in the naïve and rheumatoid arthritis model rats. In vitro calcium imaging and whole-cell patch clamp recordings in dissociated DRG neurons revealed that only the small-, but not medium- or large-sized DRG neurons responded to IgG-IC. Accordingly, in vivo electrophysiological recordings showed that intradermal injection of IgG-IC into the peripheral receptive field could sensitize only the C- (but not A-) type sensory neurons and evoke action potential discharges. Pain-related behavioral tests showed that intradermal injection of IgG-IC dose-dependently produced mechanical and thermal hyperalgesia in the hindpaw of rats. These behavioral effects could be alleviated by localized administration of non-specific IgG or an FcγRI antibody, but not by mast cell stabilizer or histamine antagonist. In a rat model of antigen-induced arthritis (AIA) produced by methylated bovine serum albumin, FcγRI were found upregulated exclusively in the small-sized DRG neurons. In vitro calcium imaging revealed that significantly more small-sized DRG neurons responded to IgG-IC in the AIA rats, although there was no significant difference between the AIA and control rats in the magnitude of calcium changes in the DRG neurons. Moreover, in vivo electrophysiological recordings showed that C-nociceptive neurons in the AIA rats exhibited a greater incidence of action potential discharges and stronger responses to mechanical stimuli after IgG-IC was injected to the receptive fields. These results suggest that FcγRI expressed in the peripheral nociceptors might be directly activated by IgG-IC and contribute to antigen-specific pain in pathological conditions.
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Affiliation(s)
- Haowu Jiang
- Department of Anatomy, Histology and Embryology, Institute of Basic Medical Sciences, Neuroscience Center, Chinese Academy of Medical Sciences, School of Basic Medicine, Peking Union Medical College, Beijing 100005, China
| | - Xinhua Shen
- Department of Anatomy, Histology and Embryology, Institute of Basic Medical Sciences, Neuroscience Center, Chinese Academy of Medical Sciences, School of Basic Medicine, Peking Union Medical College, Beijing 100005, China
| | - Zhiyong Chen
- Department of Anatomy, Histology and Embryology, Institute of Basic Medical Sciences, Neuroscience Center, Chinese Academy of Medical Sciences, School of Basic Medicine, Peking Union Medical College, Beijing 100005, China
| | - Fan Liu
- Department of Anatomy, Histology and Embryology, Institute of Basic Medical Sciences, Neuroscience Center, Chinese Academy of Medical Sciences, School of Basic Medicine, Peking Union Medical College, Beijing 100005, China
| | - Tao Wang
- Department of Anatomy, Histology and Embryology, Institute of Basic Medical Sciences, Neuroscience Center, Chinese Academy of Medical Sciences, School of Basic Medicine, Peking Union Medical College, Beijing 100005, China
| | - Yikuan Xie
- Department of Anatomy, Histology and Embryology, Institute of Basic Medical Sciences, Neuroscience Center, Chinese Academy of Medical Sciences, School of Basic Medicine, Peking Union Medical College, Beijing 100005, China
| | - Chao Ma
- Department of Anatomy, Histology and Embryology, Institute of Basic Medical Sciences, Neuroscience Center, Chinese Academy of Medical Sciences, School of Basic Medicine, Peking Union Medical College, Beijing 100005, China.
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