Hotchkiss Brain Institute
Clinical Neurosciences

Author Of 1 Presentation

Pathogenesis – Immunology Poster Presentation

P0946 - CCR2+ monocytes require EMMPRIN for migration into EAE/MS brains (ID 1169)

Speakers
Presentation Number
P0946
Presentation Topic
Pathogenesis – Immunology

Abstract

Background

Multiple sclerosis (MS) is a demyelinating condition of the central nervous system (CNS) mediated by a complex interplay of adaptive and innate immune cells. In MS and its model, experimental autoimmune encephalomyelitis (EAE), the receptor for CCL2 chemokine, CCR2, is critical for monocyte/macrophage migration into the CNS to exert their effector pathological functions. Recently, we showed that extracellular matrix metalloproteinase inducer (EMMPRIN), a glycoprotein present on monocyte/macrophage membrane, aids aerobic glycolysis (a pro-inflammatory metabolic program) within inflammatory macrophages by regulating the surface levels of monocarboxylate transporter (MCT-4), a lactate transporter.

Objectives

Our earlier studies found that neutralization of EMMPRIN activity by function blocking antibodies ameliorated EAE severity. Here, to understand specific functions and mechanisms of EMMPRIN on CCR2+ monocyte/macrophages, we investigated genetic deletion of EMMPRIN in CCR2+ monocytes.

Methods

Full length EMMPRIN was floxed using CRISPR/Cas9 (inserted 5’ flox in 1st exon and 3’ flox in 8th exon of EMMPRIN gene, Bsg2). These EMMPRIN ‘floxed’ mice were then crossed with CCR2CreERT2+mKate2 mice to yield CCR2CreERT2:EMMPRINfl/fl (EMMPRIN-/- CCR2+) tamoxifen inducible mice. EMMPRIN deletion was induced by injection of 2 mg tamoxifen/mouse every 48h starting at day 2 post EAE induction. The last injection was given on day 14. Some groups had resumption of tamoxifen regimen at day 36 until harvest. In vitro, bone marrow derived macrophages (BMDMs) were exposed to 5μM 4-hydroxytamoxifen for 24h before stimulating with LPS for another 24h for quantitative proteomics and qRT-PCR analysis.

Results

EMMPRIN-/- CCR2+ mice exhibited significantly delayed onset of EAE signs; disease severity was significantly reduced after clinical signs set in. EMMRIN-/- CCR2+ mice had significantly reduced number of perivascular cuffs during peak EAE (day 18), during which the spinal cord had significantly reduced CCR2+EMMPRIN+ monocyte/macrophages. These mice harbored elevated numbers of CCR2+ monocytes in lymph nodes suggesting an impairment of trafficking of EMMPRIN-/- CCR2+ monocytes into the CNS. In vitro, we observed alteration of proteome in EMMPRIN-/- macrophages, which was skewed towards gluconeogenesis metabolic program.

Conclusions

Selective EMMPRIN deletion in CCR2+ monocyte/macrophages alters metabolic program and interferes with their migration into EAE CNS. EMMPRIN on myeloid cells may constitute a therapeutic target in MS.

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