Enhanced expression of SOCS-2 in the rat hippocampus after transient forebrain ischemia.
Suppressor of cytokine signaling-2 (SOCS-2) has recently been identified as an important regulator involved in neuronal differentiation and maturation. However, the role of SOCS-2 in ischemia-induced hippocampal neurogenesis remains to be clarified. Here we investigated the spatiotemporal expression of SOCS-2 in the rat hippocampus following transient forebrain ischemia, and particular attention was paid to changes in the dentate gyrus. SOCS-2 mRNA was constitutively expressed in hippocampal neurons and astrocytes in control animals. However, its upregulation occurred specifically in reactive astrocytes in the hippocampus proper, in particular the CA1 and dentate hilar regions, at day 3 after reperfusion, and was sustained for more than 2 weeks. In addition to the CA1 and hilar regions, SOCS-2 was transiently increased in the subgranular zone (SGZ) of the dentate gyrus on days 3-7 after reperfusion. This correlated with the post-ischemic upregulation of SOCS-2 in the CA1 or dentate gyrus subfield, including the SGZ detected by semiquantitative reverse transcriptase-polymerase chain reaction analysis. The majority of the SOCS-2-expressing cells in the SGZ were co-labeled with glial fibrillary acidic protein (GFAP), and a subpopulation of GFAP/SOCS-2 double-labeled cells in the SGZ co-expressed the neural progenitor marker nestin, or the proliferation marker proliferating cellular nuclear antigen. In addition, a subset of SOCS-2-labeled cells in the SGZ expressed the immature neuronal marker polysialic acid-neural cell adhesion molecule. These data suggest that SOCS-2 may be involved in glial reactions, and possibly adult hippocampal neurogenesis during ischemic insults.
Choi
Jeong-Sun
JS
Department of Anatomy, College of Medicine, The Catholic University of Korea, Seoul, Korea.
Shin
Yoo-Jin
YJ
Lee
Ji-Yeon
JY
Choi
Jae-Youn
JY
Cha
Jung-Ho
JH
Chun
Myung-Hoon
MH
Lee
Mun-Yong
MY
D000818:Animals; D002545:Brain Ischemia / Q000378:metabolism*; D006624:Hippocampus / Q000378:metabolism*; D017403:In Situ Hybridization; D008297:Male; D018613:Microscopy, Confocal; D055495:Neurogenesis / Q000502:physiology; D009457:Neuroglia / Q000378:metabolism; D009474:Neurons / Q000378:metabolism; D016548:Prosencephalon / Q000098:blood supply; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D050826:Suppressor of Cytokine Signaling Proteins / Q000096:biosynthesis*; D015854:Up-Regulation
D012333:RNA, Messenger; C491408:Socs2 protein, rat; D050826:Suppressor of Cytokine Signaling Proteins