title: Secretion of interleukin-1beta by astrocytes mediates endothelin-1 and tumour necrosis factor-alpha effects on human brain microvascular endothelial cell permeability.
abstract: Evidence suggests that endothelin-1 (ET-1) plays an essential role in brain inflammation. However, whether ET-1 contributes directly to blood-brain barrier (BBB) breakdown remains to be elucidated. Using an in vitro BBB model consisting of co-cultures of human primary astrocytes and brain microvascular endothelial cells (BMVECs), we first investigated the expression of ET-1 by BMVECs upon stimulation with tumour necrosis factor (TNF)-alpha, which plays an essential role in the induction and synthesis of ET-1 during systemic inflammatory responses. Increased ET-1 mRNA was detected in the human BMVECs 24 h after TNF-alpha treatment. This was correlated with an increase in ET-1 levels in the culture medium, as determined by sandwich immunoassay. Both TNF-alpha and ET-1 increased the permeability of human BMVECs to a paracellular tracer, sucrose, but only in the presence of astrocytes. The increase in BMVEC permeability by TNF-alpha was partially prevented by antibody neutralization of ET-1 and completely by monoclonal antibody against IL-1beta. Concomitantly, TNF-alpha induced IL-1beta mRNA expression by astrocytes in co-culture and this effect was partially prevented by ET-1 antibody neutralization. In parallel experiments, treatment of human primary astrocytes in single cultures with ET-1 for 24 h induced IL-1beta mRNA synthesis and IL-1beta protein secretion in the cell culture supernatant. Taken together, these results provide evidence for paracrine actions involving ET-1, TNF-alpha and IL-1beta between human astrocytes and BMVECs, which may play a central role in BBB breakdown during CNS inflammation.
authors.affiliation: Commissariat à l'Energie Atomique (CEA), Service de Pharmacologie et d'Immunologie, Saclay, France.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Didier
authors.forename: Ignacio A
authors.initials: IA
authors.lastname: Romero
authors.forename: Christophe
authors.initials: C
authors.lastname: Créminon
authors.forename: Anne
authors.initials: A
authors.lastname: Wijkhuisen
authors.forename: Jacques
authors.initials: J
authors.lastname: Grassi
authors.forename: Aloïse
authors.initials: A
authors.lastname: Mabondzo
mesh_terms: D001253:Astrocytes / Q000166:cytology / Q000378:metabolism*; D001812:Blood-Brain Barrier / Q000187:drug effects / Q000502:physiology; D001921:Brain / Q000098:blood supply; D002199:Capillary Permeability / Q000187:drug effects* / Q000502:physiology; D002478:Cells, Cultured; D018920:Coculture Techniques; D019332:Endothelin-1 / Q000096:biosynthesis / Q000494:pharmacology*; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D006801:Humans; D007375:Interleukin-1 / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D008833:Microcirculation / Q000166:cytology; D012333:RNA, Messenger / Q000096:biosynthesis; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
chemical_list: D019332:Endothelin-1; D007375:Interleukin-1; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha