Brain-derived neurotrophic factor signalling in adult pig retinal ganglion cell neurite regeneration in vitro.
Brain-derived neurotrophic factor (BDNF) has been implicated in stimulating retinal ganglion cell (RGC) survival and axonal regeneration in rodent animal models in vivo and in vitro, but very little data are available on neurotrophin effects in higher mammals. We hence analysed BDNF signalling in primary cultures of adult pig RGC. As detected by immunohistochemistry, HPLC analysis and RT-PCR, BDNF protein and mRNA were present within pig retina in vivo and in vitro, where it may be involved in baseline RGC neuritogenesis. Initial dose-response studies established optimal effects were induced by 20 ng/ml BDNF, leading to an approximately threefold increase in neurite length. We analysed the respective contributions of phosphatidyl inositol 3 kinase (PI3K) and mitogen activated protein kinase (MAPK) cascades to BDNF-induced neurite regeneration. Addition of either the PI3K inhibitor wortmannin or the MAPK inhibitor U0126 blocked 50-100% BDNF-induced neurite elongation; U0126 also significantly reduced neurite regeneration below untreated control levels. The trk receptor inhibitor K252a had no observable effect on neurite regeneration or morphology. These data hence demonstrate that BDNF is a potent stimulator of neurite growth in RGC prepared from an adult large mammal retina, and that at least two signalling pathways are causally involved. BDNF-based therapy may be of potential use in treating RGC degeneration in humans.
Bonnet
Delphine
D
Laboratoire de Physiopathologie Cellulaire et Moléculaire de la Rétine, INSERM U. 592, Clinique Médicale A, Centre Hospitalier Universitaire, BP 426, 67091 Strasbourg, France.
Garcia
Monica
M
Vecino
Elena
E
Lorentz
Jean-Georges
JG
Sahel
José
J
Hicks
David
D
D000818:Animals; D015153:Blotting, Western / Q000379:methods; D019208:Brain-Derived Neurotrophic Factor / Q000494:pharmacology / Q000502:physiology*; D002478:Cells, Cultured; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D066298:In Vitro Techniques; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D020813:Receptor, trkB / Q000378:metabolism; D011994:Recombinant Proteins / Q000494:pharmacology; D012038:Regeneration / Q000187:drug effects / Q000502:physiology*; D012165:Retinal Ganglion Cells / Q000187:drug effects / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D015398:Signal Transduction / Q000187:drug effects*; D013552:Swine
D019208:Brain-Derived Neurotrophic Factor; D004791:Enzyme Inhibitors; D012333:RNA, Messenger; D011994:Recombinant Proteins; D020813:Receptor, trkB