title: Hypoxia-induced matrix metalloproteinase-13 expression in astrocytes enhances permeability of brain endothelial cells.
abstract: Matrix metalloproteinase-13 (MMP-13) is involved in the degradation of extracellular matrix in many kinds of tissues. Here we found that hypoxia increased MMP-13 protein and mRNA levels in primary rat astrocyte cultures. Hypoxia stimulation also increased the secretion of MMP-13 from astrocytes, as shown by zymographic analysis. In addition, exposure to hypoxia up-regulated the expression of c-Fos and c-Jun time-dependently. Hypoxia-induced MMP-13 overexpression was antagonized by transfection with antisense oligodeoxynucleotides (AS-ODN) of c-Fos or c-Jun. Furthermore, hypoxic-conditioned medium (Hx-CM) collected from astrocytes exposed to hypoxia increased paracellular permeability of adult rat brain endothelial cells (ARBECs). Administration of MMP-13 neutralizing antibody antagonized Hx-CM-induced paracellular permeability of ARBECs. Furthermore, pre-transfection of astrocytes with AS-ODN of c-Fos, c-Jun or MMP-13-shRNA significantly decreased hyperpermeability of ARBECs induced by Hx-CM. The arrangement of tight junction protein (TJP) zonular occludens-1 (ZO-1) of ARBECs disorganized in response to Hx-CM. Administration of Hx-CM to ARBECs also resulted in the production of proteolytic fragments of ZO-1, which was antagonized by transfection of MMP-13-shRNA in primary astrocytes. Administration of MMP-13 recombinant protein to ARBECs led to the disorganization and fragmentation of ZO-1 protein and also increased paracellular permeability. These results suggest that hypoxia-induced MMP-13 expression in astrocytes is regulated by c-Fos and c-Jun. MMP-13 is an important factor leading to the disorganization of ZO-1 and hyperpermeablility of blood-brain barrier in response to hypoxia.
authors.affiliation: Graduate Institute of Neural and Cognitive Sciences, China Medical University, Taichung, Taiwan.
authors.forename: Dah-Yuu
authors.initials: DY
authors.lastname: Lu
authors.forename: Wei-Hsuan
authors.initials: WH
authors.lastname: Yu
authors.forename: Wei-Lan
authors.initials: WL
authors.lastname: Yeh
authors.forename: Chih-Hsin
authors.initials: CH
authors.lastname: Tang
authors.forename: Yuk-Man
authors.initials: YM
authors.lastname: Leung
authors.forename: Kar-Lok
authors.initials: KL
authors.lastname: Wong
authors.forename: Yuh-Fung
authors.initials: YF
authors.lastname: Chen
authors.forename: Chih-Ho
authors.initials: CH
authors.lastname: Lai
authors.forename: Wen-Mei
authors.initials: WM
authors.lastname: Fu
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001253:Astrocytes / Q000201:enzymology*; D001812:Blood-Brain Barrier / Q000201:enzymology*; D001921:Brain / Q000098:blood supply* / Q000201:enzymology*; D002199:Capillary Permeability; D015687:Cell Hypoxia; D002478:Cells, Cultured; D017077:Culture Media, Conditioned / Q000378:metabolism; D042783:Endothelial Cells / Q000201:enzymology*; D053509:Matrix Metalloproteinase 13 / Q000235:genetics / Q000378:metabolism*; D008565:Membrane Proteins / Q000378:metabolism; D010750:Phosphoproteins / Q000378:metabolism; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism; D016755:Proto-Oncogene Proteins c-jun / Q000378:metabolism; D034622:RNA Interference; D012333:RNA, Messenger / Q000378:metabolism; D034741:RNA, Small Interfering / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D011994:Recombinant Proteins / Q000378:metabolism; D019108:Tight Junctions / Q000201:enzymology; D013997:Time Factors; D014162:Transfection; D015854:Up-Regulation; D062826:Zonula Occludens-1 Protein
chemical_list: D017077:Culture Media, Conditioned; D008565:Membrane Proteins; D010750:Phosphoproteins; D016760:Proto-Oncogene Proteins c-fos; D016755:Proto-Oncogene Proteins c-jun; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D011994:Recombinant Proteins; C569044:Tjp1 protein, rat; D062826:Zonula Occludens-1 Protein; D053509:Matrix Metalloproteinase 13; C507083:Mmp13 protein, rat