Journal Article

Regulatory T cells require peripheral CCL2-CCR2 signaling to facilitate the resolution of medication overuse headache-related behavioral sensitization

Zhang, Jintao, Liu, Xuemei, Feng, Li, Cao, Yu-Qing, Unsinger, Jacqueline, Hotchkiss, Richard S., Guo, Zhaohua, Simoes, Roli, Ryu, Sun

2024

Overview

Background Medication overuse headache (MOH) is the most common secondary headache disorder, resulting from chronic and excessive use of medication to treat headaches, for example, sumatriptan. In a recent study, we have shown that the peripheral C-C motif ligand 2 (CCL2), C-C motif chemokine receptor 2 (CCR2) and calcitonin-gene-related peptide (CGRP) signaling pathways interact with each other and play critical roles in the development of chronic migraine-related behavioral and cellular sensitization. In the present study, we investigated whether CCL2-CCR2 and CGRP signaling pathways play a role in the development of sumatriptan overuse-induced sensitization, and whether they are involved in its resolution by the low-dose interleukin-2 (LD-IL-2) treatment. Methods Mice received daily sumatriptan administration for 12 days. MOH-related behavioral sensitization was assessed by measuring changes of periorbital mechanical thresholds for 3 weeks. CCL2-CCR2 and CGRP signaling pathways were inhibited by targeted gene deletion or with an anti-CCL2 antibody. Ca 2+ -imaging was used to examine whether repetitive sumatriptan treatment enhances CGRP and pituitary adenylate cyclase–activating polypeptide (PACAP) signaling in trigeminal ganglion (TG) neurons. LD-IL-2 treatment was initiated after the establishment of sumatriptan-induced sensitization. Immunohistochemistry and flow cytometry analyses were used to examine whether CCL2-CCR2 signaling controls regulatory T (Treg) cell proliferation and/or trafficking. Results CCL2, CCR2 and CGRPα global KO mice exhibited robust sumatriptan-induced behavioral sensitization comparable to wild-type controls. Antibody neutralization of peripheral CCL2 did not affect sumatriptan-induced behaviors either. Repeated sumatriptan administration did not enhance the strength of CGRP or PACAP signaling in TG neurons. Nevertheless, LD-IL-2 treatment, which facilitated the resolution of sumatriptan-induced sensitization in wild-type and CGRPα KO mice, was completely ineffective in mice with compromised CCL2-CCR2 signaling. In CCL2 KO mice, we observed normal LD-IL-2-induced Treg expansion in peripheral blood, but the increase of Treg cells in dura and TG tissues was significantly reduced in LD-IL-2-treated CCL2 KO mice relative to wild-type controls. Conclusions These results indicate that the endogenous CCL2-CCR2 and CGRP signaling pathways are not involved in sumatriptan-induced behavioral sensitization, suggesting that distinct molecular mechanisms underlie chronic migraine and MOH. On the other hand, peripheral CCL2-CCR2 signaling is required for LD-IL-2 to reverse chronic headache-related sensitization. Graphical abstract

• Publisher: Springer Milan,Springer Nature B.V,BMC
• Subject: Animals / C-C motif chemokine receptor 2 (CCR2) / C-C motif ligand 2 (CCL2) / Calcitonin / Calcitonin gene-related peptide / Calcitonin gene-related peptide (CGRP) / Calcitonin Gene-Related Peptide - metabolism / Calcium imaging / Calcium signalling / CC chemokine receptors / Cell proliferation / Chemokine CCL2 - metabolism / Chemokine receptors / Facial mechanical hypersensitivity / Flow cytometry / Gene deletion / Headache / Headache Disorders, Secondary - drug therapy / Headaches / Health behavior / Immunohistochemistry / Immunoregulation / Interleukin 2 / Internal Medicine / Lymphocytes T / Male / Mechanical properties / Medication overuse headache / Medicine / Medicine & Public Health / Mice / Mice, Inbred C57BL / Mice, Knockout / Migraine / Molecular modelling / Monocyte chemoattractant protein 1 / Neuroimmune Interplay in Headache / Neurology / Pain Medicine / Peripheral blood / Pituitary adenylate cyclase-activating polypeptide / Receptors, CCR2 - metabolism / Regulatory T (Treg) cell / Signal transduction / Signal Transduction - drug effects / Signal Transduction - physiology / Sumatriptan / Sumatriptan - administration & dosage / Sumatriptan - pharmacology / T-Lymphocytes, Regulatory - drug effects / T-Lymphocytes, Regulatory - immunology / Trigeminal ganglion