title: Stromal cell-derived CCL2 drives neuropathic pain states through myeloid cell infiltration in injured nerve.
abstract: Neuropathic pain resulting from peripheral nerve injury involves many persistent neuroinflammatory processes including inflammatory chemokines that control leukocyte trafficking and activate resident cells. Several studies have shown that CCL2 chemokine, a potent attractant of monocytes, and its cognate receptor, CCR2, play a critical role in regulating nociceptive processes during neuropathic pain. However, the role of CCL2 in peripheral leukocyte infiltration-associated neuropathic pain remains poorly understood. In particular, the contribution of individual CCL2-expressing cell populations (i.e. stromal and leukocytes) to immune cell recruitment into the injured nerve has not been established. Here, in preclinical model of peripheral neuropathic pain (i.e. chronic constriction injury of the sciatic nerve), we have demonstrated that, CCL2 content was increased specifically in nerve fibers. This upregulation of CCL2 correlated with local monocyte/macrophage infiltration and pain processing. Furthermore, sciatic intraneural microinjection of CCL2 in naïve animals triggered long-lasting pain behavior associated with local monocyte/macrophage recruitment. Using a specific CCR2 antagonist and mice with a CCL2 genetic deletion, we have also established that the CCL2/CCR2 axis drives monocyte/macrophage infiltration and pain hypersensitivity in the CCI model. Finally, specific deletion of CCL2 in stromal or immune cells respectively using irradiated bone marrow-chimeric CCI mice demonstrated that stromal cell-derived CCL2 (in contrast to CCL2 immune cell-derived) tightly controls monocyte/macrophage recruitment into the lesion and plays a major role in the development of neuropathic pain. These findings demonstrate that in chronic pain states, CCL2 expressed by sciatic nerve cells predominantly drove local neuro-immune interactions and pain-related behavior through CCR2 signaling.
authors.affiliation: UMR 1141 INSERM, Hôpital Robert Debré, F-75019, Paris, France; Université Paris Diderot, Faculté de Médecine, F-75019, Paris, France; PremUP, 75014 Paris, France.
authors.forename: Juliette
authors.initials: J
authors.lastname: Van Steenwinckel
authors.affiliation: Sorbonne Universités, UPMC Université Paris 06, CR7, Centre d'Immunologie et des Maladies Infectieuses (CIMI-Paris). 91 Bd de l'hôpital, F-75013, Paris, France; Inserm, U1135, CIMI-Paris, 91 Bd de l'hôpital, F-75013, Paris, France; CNRS, ERL 8255, CIMI-Paris, 91 Bd de l'hôpital, F-75013, Paris, France.
authors.forename: Constance
authors.initials: C
authors.lastname: Auvynet
authors.affiliation: Sorbonne Universités, UPMC Université Paris 06, Institut de la vision, équipe S12, 17 rue Moreau, F-75012, Paris, France; UMR_S 968 INSERM, 17 rue Moreau, F-75012, Paris, France; UMR 7210 CNRS, 17 rue Moreau, F-75012, Paris, France.
authors.forename: Anaïs
authors.initials: A
authors.lastname: Sapienza
authors.affiliation: Sorbonne Universités, UPMC Université Paris 06, Institut de la vision, équipe S12, 17 rue Moreau, F-75012, Paris, France; UMR_S 968 INSERM, 17 rue Moreau, F-75012, Paris, France; UMR 7210 CNRS, 17 rue Moreau, F-75012, Paris, France.
authors.forename: Annabelle
authors.initials: A
authors.lastname: Reaux-Le Goazigo
authors.affiliation: Sorbonne Universités, UPMC Université Paris 06, CR7, Centre d'Immunologie et des Maladies Infectieuses (CIMI-Paris). 91 Bd de l'hôpital, F-75013, Paris, France; Inserm, U1135, CIMI-Paris, 91 Bd de l'hôpital, F-75013, Paris, France; CNRS, ERL 8255, CIMI-Paris, 91 Bd de l'hôpital, F-75013, Paris, France.
authors.forename: Christophe
authors.initials: C
authors.lastname: Combadière
authors.affiliation: Sorbonne Universités, UPMC Université Paris 06, Institut de la vision, équipe S12, 17 rue Moreau, F-75012, Paris, France; UMR_S 968 INSERM, 17 rue Moreau, F-75012, Paris, France; UMR 7210 CNRS, 17 rue Moreau, F-75012, Paris, France. Electronic address: stephane.melik-parsadaniantz@inserm.fr.
authors.forename: Stéphane
authors.initials: S
authors.lastname: Melik Parsadaniantz
mesh_terms: D000818:Animals; D016026:Bone Marrow Transplantation; D018932:Chemokine CCL2 / Q000276:immunology*; D003251:Constriction, Pathologic; D006930:Hyperalgesia / Q000235:genetics / Q000276:immunology; D008264:Macrophages / Q000276:immunology*; D051379:Mice; D009000:Monocytes / Q000276:immunology*; D022423:Myeloid Cells / Q000276:immunology; D009437:Neuralgia / Q000276:immunology*; D059348:Peripheral Nerve Injuries / Q000276:immunology*; D051381:Rats; D012584:Sciatic Nerve / Q000276:immunology / Q000293:injuries*; D015854:Up-Regulation
chemical_list: C491768:Ccl2 protein, mouse; C491766:Ccl2 protein, rat; D018932:Chemokine CCL2
keywords: CCL2; Chemokine; FACS; Irradiated bone marrow-chimeric mice; Macrophages; Neuropathic pain; Nociceptive behavior