High Mobility Group Box 1 as an Autocrine Chemoattractant for Oligodendrocyte Lineage Cells in White Matter Stroke. Issue 2 (7th December 2022)

• Record Type: Journal Article
• Authors: Choi, Jun Young; Jin, Xuelian; Kim, Hanki; Koh, Seungyon; Cho, Hyo Jin; Kim, Byung Gon
• Is Part Of: Stroke. Volume 54:Issue 2(2023)
• Page Start: 575
• Page End: 586
• Publication Date: 2022-12-07
• Subjects: internal capsule -- ischemic stroke -- microglia -- oligodendroglia -- white matter; Cerebrovascular disease -- Periodicals; Cerebral circulation -- Periodicals; 616.81
• DOI: 10.1161/STROKEAHA.122.041414
• Languages: English
• ISSNs: 0039-2499

Abstract

Abstract : Background: The migration of oligodendrocyte precursor cells (OPC) is a key process of remyelination, which is essential for the treatment of white matter stroke. This study aimed to investigate the role of HMGB1 (high mobility group box 1), a damage-associated molecular pattern released from dying oligodendrocytes, as an autocrine chemoattractant that promotes OPC migration. Methods: The migratory capacity of primary cultured OPCs was measured using the Boyden chamber assay. The downstream pathway of HMGB1-mediated OPC migration was specified by siRNA-induced knockdown or pharmacological blockade of TLR2 (toll-like receptor 2), RAGE (receptor for advanced glycation end product), Src, ERK1/2 (extracellular signal-regulated kinase1/2), and FAK (focal adhesion kinase). Conditioned media were collected from oxygen-glucose deprivation-treated oligodendrocytes, and the impact on OPC migration was assessed. Lesion size and number of intralesional Olig2(+) cells were analyzed in an in vivo model of white matter stroke with N5-(1-iminoethyl)-L-ornithine (L-NIO). Results: HMGB1 treatment promoted OPC migration. HMGB1 antagonism reversed such effects to untreated levels. Among the candidates for the downstream signal of HMGB1-mediated migration, the knockdown of TLR2 rather than that of RAGE attenuated the migration-promoting effect of HMGB1. Further specification of the HMGB1-TLR2 axis revealed that the phosphorylation of ERK1/2 and its downstream molecule FAK, rather than of Src, was decreased in TLR2-knockdown OPCs, and pharmacological inhibition of ERK1/2 and FAK led to decreased OPC migration. Oxygen-glucose deprivation-conditioned media promoted OPC migration, suggesting the autocrine chemoattractant function of HMGB1. In vivo, TLR2(−/−)-mice showed lesser intralesional Olig2(+) cells compared to wild-type controls in response to L-NIO induced ischemic injury regardless of HMGB1 administration. Conclusions: HMGB1, through the TLR2-ERK1/2-FAK axis, functions as an autocrine chemoattractant to promote OPC migration, which is an initial and indispensable step in remyelination. Thus, a novel treatment strategy for white matter stroke based on the HMGB1-TLR2 axis in the oligodendrocyte lineage could be feasible.