title: Increased FGF-2 secretion and ability to support neurite outgrowth by astrocytes cultured on polyamide nanofibrillar matrices.
abstract: An electrospun nonwoven matrix of polyamide nanofibers was employed as a new model for the capillary basement membrane at the blood-brain barrier (BBB). The basement membrane separates astrocytes from endothelial cells and is associated with growth factors, such as fibroblast growth factor-2 (FGF-2). FGF-2 is produced by astrocytes and induces specialized functions in endothelial cells, but also has actions on astrocytes. To investigate potential autocrine actions of FGF-2 at the BBB, astrocytes were cultured on unmodified nanofibers or nanofibers covalently modified with FGF-2. The former assumed an in vivo-like stellate morphology that was enhanced in the presence of cross-linked FGF-2. Furthermore, astrocyte monolayers established on unmodified nanofibers were more permissive for neurite outgrowth when cultured with an overlay of neurons than similar monolayers established on standard tissue culture surfaces, while astrocytes cultured on FGF-2-modifed nanofibers were yet more permissive. The observed differences were due in part to progressively increasing amounts of FGF-2 secreted by the astrocytes into the medium; hence FGF-2 increases its own expression in astrocytes to modulate astrocyte-neuron interactions. Soluble FGF-2 was unable to replicate the effects of cross-linked FGF-2. Nanofibers alone up-regulated FGF-2, albeit to a lesser extent than nanofibers covalently modified with FGF-2. These results underscore the importance of both surface topography and growth factor presentation on cellular function. Moreover, these results indicate that FGF-2-modified nanofibrillar scaffolds may demonstrate utility in tissue engineering applications for replacement and regeneration of lost tissue following central nervous system (CNS) injury or disease.
authors.affiliation: Department of Pharmacology, UMDNJ-Robert Wood Johnson Medical School, Piscataway, NJ 08854, USA.
authors.forename: Roberto
authors.initials: R
authors.lastname: Delgado-Rivera
authors.forename: Suzan L
authors.initials: SL
authors.lastname: Harris
authors.forename: Ijaz
authors.initials: I
authors.lastname: Ahmed
authors.forename: Ashwin N
authors.initials: AN
authors.lastname: Babu
authors.forename: Ripal P
authors.initials: RP
authors.lastname: Patel
authors.forename: Virginia
authors.initials: V
authors.lastname: Ayres
authors.forename: Dexter
authors.initials: D
authors.lastname: Flowers
authors.forename: Sally
authors.initials: S
authors.lastname: Meiners
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D000906:Antibodies / Q000276:immunology / Q000494:pharmacology; D001253:Astrocytes / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D001485:Basement Membrane / Q000166:cytology / Q000378:metabolism; D001812:Blood-Brain Barrier / Q000166:cytology / Q000378:metabolism; D018929:Cell Culture Techniques / Q000379:methods; D002540:Cerebral Cortex / Q000166:cytology; D018920:Coculture Techniques; D017077:Culture Media, Conditioned / Q000494:pharmacology; D016222:Fibroblast Growth Factor 2 / Q000737:chemistry / Q000276:immunology / Q000378:metabolism*; D057927:Hydrophobic and Hydrophilic Interactions; D018625:Microscopy, Atomic Force; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure; D016501:Neurites / Q000737:chemistry / Q000502:physiology* / Q000648:ultrastructure; D009474:Neurons / Q000166:cytology; D009757:Nylons / Q000737:chemistry*; D051381:Rats; D017207:Rats, Sprague-Dawley; D054457:Tissue Scaffolds / Q000737:chemistry; D014404:Tubulin / Q000032:analysis
chemical_list: D000906:Antibodies; D017077:Culture Media, Conditioned; D009757:Nylons; D014404:Tubulin; D016222:Fibroblast Growth Factor 2