title: Chemokine receptor CXCR2 in dorsal root ganglion contributes to the maintenance of inflammatory pain.
abstract: Chemokines and their receptors have been demonstrated to be important contributors to the development and maintenance of chronic pain. Recent studies showed that chemokine (C-X-C motif) ligand 1 (CXCL1) and its major receptor CXCR2 are respectively expressed in astrocytes and neurons in the spinal cord and are involved in the maintenance of neuropathic pain and inflammatory pain via astrocytic-neuronal interaction. Here we investigated how CXCL1 and CXCR2 are regulated in the dorsal root ganglion (DRG) after peripheral injection of complete Freund's adjuvant (CFA) and its implication in inflammatory pain. CFA induced rapid increase of CXCL1 mRNA and protein in the DRG. Double immunostaining showed that CXCL1 was colocalized with calcitonin gene-related peptide (CGRP), isolectin B4 (IB4), and neurofilament 200 (NF200). Furthermore, CXCR2 mRNA was increased 3h after CFA injection and maintained for more than 3 days. CXCR2 protein was also increased and colocalized with CGRP, IB4, and NF200. Finally, perisciatic nerve injection of CXCR2 siRNA to specifically knock down CXCR2 in the DRG effectively attenuated CFA-induced mechanical allodynia and heat hyperalgesia, and the effect maintained for more than 5 days. Taken together, our results demonstrated that CXCL1 and CXCR2 may regulate the maintenance of inflammatory pain via an autocrine/paracrine way in DRG neurons.
authors.affiliation: Pain Research Laboratory, Institute of Nautical Medicine, Jiangsu Key laboratory of Neuroregeneration, Nantong University, Jiangsu 226001, China.
authors.forename: De-Li
authors.initials: DL
authors.lastname: Cao
authors.affiliation: Department of Anesthesiology, The First People's Hospital of Yancheng, Jiangsu 224005, China.
authors.forename: Bin
authors.initials: B
authors.lastname: Qian
authors.affiliation: Pain Research Laboratory, Institute of Nautical Medicine, Jiangsu Key laboratory of Neuroregeneration, Nantong University, Jiangsu 226001, China.
authors.forename: Zhi-Jun
authors.initials: ZJ
authors.lastname: Zhang
authors.affiliation: Pain Research Laboratory, Institute of Nautical Medicine, Jiangsu Key laboratory of Neuroregeneration, Nantong University, Jiangsu 226001, China; Co-innovation Center of Neuroregeneration, Nantong University, Jiangsu 226001, China.
authors.forename: Yong-Jing
authors.initials: YJ
authors.lastname: Gao
authors.affiliation: Pain Research Laboratory, Institute of Nautical Medicine, Jiangsu Key laboratory of Neuroregeneration, Nantong University, Jiangsu 226001, China. Electronic address: wurunyu123456@163.com.
authors.forename: Xiao-Bo
authors.initials: XB
authors.lastname: Wu
mesh_terms: D000818:Animals; D015740:Calcitonin Gene-Related Peptide / Q000378:metabolism; D054360:Chemokine CXCL1 / Q000378:metabolism; D005620:Freund's Adjuvant; D005727:Ganglia, Spinal / Q000378:metabolism* / Q000473:pathology; D006023:Glycoproteins / Q000378:metabolism; D007249:Inflammation / Q000378:metabolism* / Q000473:pathology; D008297:Male; D008813:Mice, Inbred ICR; D016900:Neurofilament Proteins / Q000378:metabolism; D010146:Pain / Q000378:metabolism* / Q000473:pathology; D012333:RNA, Messenger / Q000378:metabolism; D023063:Receptors, Interleukin-8B / Q000037:antagonists & inhibitors / Q000378:metabolism*; D013997:Time Factors
chemical_list: D054360:Chemokine CXCL1; C475895:Cxcl1 protein, mouse; D006023:Glycoproteins; D016900:Neurofilament Proteins; D012333:RNA, Messenger; D023063:Receptors, Interleukin-8B; C473590:isolectin B4-binding glycoprotein, mouse; C051774:neurofilament protein H; D005620:Freund's Adjuvant; D015740:Calcitonin Gene-Related Peptide
keywords: CXCR2; Chemokine (C-X-C motif) ligand 1; Complete Freund’s adjuvant; Dorsal root ganglion