MCP-1/CCR2 signaling-mediated astrocytosis is accelerated in a transgenic mouse model of SOD1-mutated familial ALS

Motoko Kawaguchi-Niida,Yuri Inose,Yoichiro Kato,Noriyuki Shibata,Tomoko Yamamoto

doi:10.1186/2051-5960-1-21

Motoko Kawaguchi-Niida, Yuri Inose + Show 3 more

Open Access

https://doi.org/10.1186/2051-5960-1-21

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Abstract

BackgroundEmerging evidence suggests that innate immunity and increased oxidative stress contribute to pathomechanisms in amyotrophic lateral sclerosis (ALS). The aim of the present study was to verify the involvement of monocyte chemoattractant protein-1 (MCP-1) and its specific CC chemokine receptor 2 (CCR2) in the disease progression of ALS. We here demonstrate the expression state of MCP-1 and CCR2 in lumbar spinal cords of mice overexpressing a transgene for G93A mutant human superoxide dismutase 1 (SOD1) (ALS mice) as a mouse model of ALS as well as the involvement of MCP-1/CCR2-mediated signaling in behavior of cultured astrocytes derived from those mice.ResultsQuantitative polymerase chain reaction analysis revealed that MCP-1 and CCR2 mRNA levels were significantly higher in ALS mice than those in nontransgenic littermates (control mice) at the presymptomatic stage. Immunoblot analysis disclosed a significantly higher CCR2/β-actin optical density ratio in the postsymptomatic ALS mouse group than those in the age-matched control mouse group. Immunohistochemically, MCP-1 determinants were mainly localized in motor neurons, while CCR2 determinants were exclusively localized in reactive astrocytes. Primary cultures of astrocytes derived from ALS mice showed a significant increase in proliferation activity under recombinant murine MCP-1 stimuli as compared to those from control mice.ConclusionsOur results provide in vivo and in vitro evidence that MCP-1 stimulates astrocytes via CCR2 to induce astrocytosis in ALS with SOD1 gene mutation. Thus, it is likely that MCP-1/CCR2-mediated sigaling is involved in the disease progression of ALS.

Highlights

Emerging evidence suggests that innate immunity and increased oxidative stress contribute to pathomechanisms in amyotrophic lateral sclerosis (ALS)
monocyte chemoattractant protein-1 (MCP-1) and chemokine receptor 2 (CCR2) mRNA levels are changed in the spinal cord of ALS mice Using reverse transcriptionquantitative polymerase chain reaction (RT-qPCR) techniques, expression levels of MCP-1 and CCR2 mRNA in lumbar spinal cords from G1H+/− (ALS mice) and strain of Jackson Laboratory line (SJL) mice were quantitatively compared between the presymptomatic (9-weeks-old mice), onset (12-weeks-old mice), and postsymptomatic (15-weeksold mice) groups
Taken together, we here showed a significant upregulation of MCP-1 and CCR2 in the spinal cord of G93A mutant human superoxide dismutase 1 (SOD1)-overexpressing mice relative to nontransgenic littermates

Summary

Introduction

Emerging evidence suggests that innate immunity and increased oxidative stress contribute to pathomechanisms in amyotrophic lateral sclerosis (ALS). The complete pathomechanism of ALS has not yet been understood, several studies have obtained evidence that inflammatory processes, including increased levels of proinflammatory cytokines and proliferation and activation of glial cells in the main lesions, are involved in the disease progression [4]. Our previous report showed increased levels of activated form of p38 mitogen-activated protein kinase (MAPK) and reduced levels of inhibitor of kappa B-alpha (IκBα) in G93A mutant SOD1 transgenic mice as well as a beneficial effect of pioglitazone, an antiinflammatory agent of the thiazolidinedione group and an artificial agonist of peroxisome proliferator-activated receptor gamma, on survival of motor neurons and suppression of glial activation through inhibition of p38 MAPK activation and upregulation of IκBα expression [5]

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