Clearance of peripheral nerve misfolded mutant protein by infiltrated macrophages correlates with motor neuron disease progression

Wataru Shiraishi, Ryo Yamasaki, Yu Hashimoto, Senri Ko, Yuko Kobayakawa, Noriko Isobe, Takuya Matsushita, Jun ichi Kira

Research output: Contribution to journalArticlepeer-review

Abstract

Macrophages expressing C–C chemokine receptor type 2 (CCR2) infiltrate the central and peripheral neural tissues of amyotrophic lateral sclerosis (ALS) patients. To identify the functional role of CCR2+ macrophages in the pathomechanisms of ALS, we used an ALS animal model, mutant Cu/Zn superoxide dismutase 1G93A (mSOD1)-transgenic (Tg) mice. To clarify the CCR2 function in the model, we generated SOD1G93A/CCR2Red fluorescence protein (RFP)/Wild type (WT)/CX3CR1Green fluorescence protein (GFP)/WT-Tg mice, which heterozygously express CCR2-RFP and CX3CR1-GFP, and SOD1G93A/CCR2RFP/RFP-Tg mice, which lack CCR2 protein expression and present with a CCR2-deficient phenotype. In mSOD1-Tg mice, mSOD1 accumulated in the sciatic nerve earlier than in the spinal cord. Furthermore, spinal cords of SOD1G93A/CCR2RFP/WT/CX3CR1GFP/WT mice showed peripheral macrophage infiltration that emerged at the end-stage, whereas in peripheral nerves, macrophage infiltration started from the pre-symptomatic stage. Before disease onset, CCR2+ macrophages harboring mSOD1 infiltrated sciatic nerves earlier than the lumbar cord. CCR2-deficient mSOD1-Tg mice showed an earlier onset and axonal derangement in the sciatic nerve than CCR2-positive mSOD1-Tg mice. CCR2-deficient mSOD1-Tg mice showed an increase in deposited mSOD1 in the sciatic nerve compared with CCR2-positive mice. These findings suggest that CCR2+ and CX3CR1+ macrophages exert neuroprotective functions in mSOD1 ALS via mSOD1 clearance from the peripheral nerves.

Original languageEnglish
Article number16438
JournalScientific reports
Volume11
Issue number1
DOIs
Publication statusPublished - Dec 2021

All Science Journal Classification (ASJC) codes

  • General

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