A Novel CMKLR1 Small Molecule Antagonist Suppresses CNS Autoimmune Inflammatory Disease

Kareem L Graham,Susanna Lewén,Thomas M Burke,Jian V Zhang,Eugene C Butcher,Raymond A Sobel,Maria Zoudilova,Brian A Zabel,Ton Dang,Michael Platten

doi:10.1371/journal.pone.0112925

Abstract

Therapies that target leukocyte trafficking pathways can reduce disease activity and improve clinical outcomes in multiple sclerosis (MS). Experimental autoimmune encephalomyelitis (EAE) is a widely studied animal model that shares many clinical and histological features with MS. Chemokine-like receptor-1 (CMKLR1) is a chemoattractant receptor that is expressed by key effector cells in EAE and MS, including macrophages, subsets of dendritic cells, natural killer cells and microglia. We previously showed that CMKLR1-deficient (CMKLR1 KO) mice develop less severe clinical and histological EAE than wild-type mice. In this study, we sought to identify CMKLR1 inhibitors that would pharmaceutically recapitulate the CMKLR1 KO phenotype in EAE. We identified 2-(α-naphthoyl) ethyltrimethylammonium iodide (α-NETA) as a CMKLR1 small molecule antagonist that inhibits chemerin-stimulated β-arrestin2 association with CMKLR1, as well as chemerin-triggered CMKLR1+ cell migration. α-NETA significantly delayed the onset of EAE induced in C57BL/6 mice by both active immunization with myelin oligodendrocyte glycoprotein peptide 35-55 and by adoptive transfer of encephalitogenic T cells. In addition, α-NETA treatment significantly reduced mononuclear cell infiltrates within the CNS. This study provides additional proof-of-concept data that targeting CMKLR1:chemerin interactions may be beneficial in preventing or treating MS.

Highlights

Multiple sclerosis (MS) is a demyelinating disease of the CNS that affects approximately 2 million people worldwide
Results a-NETA is a novel inhibitor of chemerin-stimulated b-arrestin2 association with Chemokine-like receptor-1 (CMKLR1)
We identified 2-(a-naphthoyl)ethyltrimethylammonium iodide (a-NETA) as a potent inhibitor of chemerin-stimulated b-ARR2 association with CMKLR1, IC50: 375¡42 nM (n514, mean ¡ SEM, Fig. 1B)

Summary

Introduction

Multiple sclerosis (MS) is a demyelinating disease of the CNS that affects approximately 2 million people worldwide. Therapies that target leukocyte trafficking pathways can reduce disease activity and improve clinical outcomes in MS. Agents that selectively target the trafficking of key inflammatory cell subsets involved in the pathophysiology of MS may be superior to current treatment strategies. Chemerin co-localizes with intralesional endothelial cells in the brains of MS patients, and CMKLR1+ dendritic cells are present in the leptomeninges and in perivascular cuffs of chronic and active MS lesions [13]. Suitable pharmaco-inhibitors of CMKLR1, remain to be identified and tested in models of autoimmune CNS inflammation. We used a functional whole-cell assay to screen for novel small molecule inhibitors of CMKLR1 activity, with the goal of identifying lead compounds for evaluation in the EAE model of MS

Methods

Results

Conclusion