title: GDNF, Ret, GFRalpha1 and 2 in the adult rat retino-tectal system after optic nerve transection.
abstract: In the present study, we have studied the expression of glial cell line-derived neurotrophic factor (GDNF) and its receptors Ret, GFRalpha1, and GFRalpha2 in the retino-tectal system before and after optic nerve transection. Using retrograde neuronal tracing in combination with in situ hybridization, we found that Ret and GFRalpha1 are expressed by 13-14% of the retinal ganglion cells (RGCs). These Ret-expressing RGCs could not be identified as belonging to any particular of the RG(A), RG(B), and RG(C) sub types. Ret is co-expressed with the brain-derived neurotrophic factor receptor TrkB in these RGCs. Optic nerve transection resulted in reduced Ret mRNA levels in retina, while the levels of GDNF, GFRalpha1, and 2 mRNA increased. Administration of GDNF protein supported the axotomized RGCs. Analysis of normal superior colliculus (SC) did not show any expression of GDNF mRNA, yet GDNF mRNA levels in SC increased after injury. Together, these findings identify a portion of RGCs as being possible targets for pharmacological treatment with GDNF in a direct mode of action. The absence of detectable GDNF mRNA in normal SC questions the role for GDNF as being a target-derived factor produced in the SC for adult RGCs. The results support a function for GDNF locally in the retina and as part of an injury-induced system that may act to enhance neuroprotective and neuroregenerative responses both to endogenous GDNF ligands and those administered exogenously.
authors.affiliation: Department of Neuroscience, Unit for Developmental Neuroscience, Uppsala University, Uppsala, Sweden.
authors.forename: Niclas
authors.initials: N
authors.lastname: Lindqvist
authors.forename: Paloma
authors.initials: P
authors.lastname: Peinado-Ramónn
authors.forename: Manuel
authors.initials: M
authors.lastname: Vidal-Sanz
authors.forename: Finn
authors.initials: F
authors.lastname: Hallböök
mesh_terms: D016475:3T3 Cells; D000818:Animals; D002470:Cell Survival / Q000187:drug effects; D004333:Drug Administration Routes; D005260:Female; D005347:Fibroblasts / Q000378:metabolism / Q000637:transplantation; D051100:Glial Cell Line-Derived Neurotrophic Factor; D051097:Glial Cell Line-Derived Neurotrophic Factor Receptors; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D051379:Mice; D009414:Nerve Growth Factors / Q000096:biosynthesis / Q000235:genetics* / Q000494:pharmacology; D020221:Optic Nerve Injuries / Q000378:metabolism* / Q000473:pathology; D011518:Proto-Oncogene Proteins / Q000235:genetics* / Q000378:metabolism; D051096:Proto-Oncogene Proteins c-ret; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D011916:Rats, Inbred F344; D017207:Rats, Sprague-Dawley; D020794:Receptor Protein-Tyrosine Kinases / Q000235:genetics* / Q000378:metabolism; D012160:Retina / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D012165:Retinal Ganglion Cells / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D013477:Superior Colliculi / Q000378:metabolism* / Q000473:pathology
chemical_list: C495040:Gdnf protein, mouse; C495041:Gdnf protein, rat; C494988:Gfra1 protein, mouse; C494991:Gfra2 protein, mouse; C494992:Gfra2 protein, rat; D051100:Glial Cell Line-Derived Neurotrophic Factor; D051097:Glial Cell Line-Derived Neurotrophic Factor Receptors; D009414:Nerve Growth Factors; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D051096:Proto-Oncogene Proteins c-ret; D020794:Receptor Protein-Tyrosine Kinases; C494999:Ret protein, mouse; C495001:Ret protein, rat