title: Expression of SOCS2 mRNA and protein in the ischemic core and penumbra after transient focal cerebral ischemia in rats.
abstract: The suppressor of cytokine signaling 2 (SOCS2) has been reported to be involved in astroglial reactions and adult neurogenesis in the ischemic hippocampus. To elucidate whether SOCS2 is implicated in the pathophysiology of stroke, we investigate spatiotemporal regulation and identification of cell phenotypes expressing SOCS2 after transient focal cerebral ischemia. Weak hybridization signals for SOCS2 mRNA were constitutively observed in striatal neurons and upregulation of SOCS2 mRNA was induced in association with nestin-positive cells in stroke-lesioned rats. Analysis of the characteristics and phenotypes of SOCS2/nestin double-labeled cells revealed spatial differences between infarct and peri-infarct areas. SOCS2/nestin double-labeled cells in the infarct area were associated with the vasculature and were highly proliferative. In contrast, the double-labeled cells in the peri-infarct area were indeed glial fibrillary acidic protein (GFAP)-positive reactive astrocytes forming the glial scar, although nestin-negative reactive astrocytes also exhibited weak SOCS2 expression. In addition, induction of SOCS2 expression was observed in Iba1-positive cells showing a macrophage-like phenotype with amoeboid morphology; these cells were predominantly localized in the infarct area. In the peri-infarct area, only a small proportion of Iba1-positive cells with the morphology of brain macrophages expressed SOCS2 and most activated stellate microglial cells with thick and short processes exhibited weak or negligible SOCS2 expression. Thus, our results revealed the phenotypic and functional heterogeneity of SOCS2-expressing cells within infarct and peri-infarct areas, suggesting the involvement of SOCS2 in astroglial reactions and activation/recruitment of brain macrophages and its potential role in perivascular progenitors/stem cells after ischemic stroke.
authors.affiliation: Department of Anatomy, Catholic Neuroscience Institute, College of Medicine, The Catholic University of Korea, Seoul, 137-701, South Korea. dbwls612@catholic.ac.kr.
authors.forename: Yoo-Jin
authors.initials: YJ
authors.lastname: Shin
authors.affiliation: Department of Anatomy, Catholic Neuroscience Institute, College of Medicine, The Catholic University of Korea, Seoul, 137-701, South Korea.
authors.forename: Tae-Ryong
authors.initials: TR
authors.lastname: Riew
authors.affiliation: Department of Anatomy, Catholic Neuroscience Institute, College of Medicine, The Catholic University of Korea, Seoul, 137-701, South Korea.
authors.forename: Joo-Hee
authors.initials: JH
authors.lastname: Park
authors.affiliation: Department of Anatomy, Catholic Neuroscience Institute, College of Medicine, The Catholic University of Korea, Seoul, 137-701, South Korea.
authors.forename: Ha-Jin
authors.initials: HJ
authors.lastname: Pak
authors.affiliation: Department of Anatomy, Catholic Neuroscience Institute, College of Medicine, The Catholic University of Korea, Seoul, 137-701, South Korea. munylee@catholic.ac.kr.
authors.forename: Mun-Yong
authors.initials: MY
authors.lastname: Lee
keywords: Brain macrophages; Focal ischemia; Nestin; Reactive astrocytes; Suppressor of cytokine signaling 2