Brain-derived neurotrophic factor supports the survival of cultured rat retinal ganglion cells

Abstract

Brain-derived neurotrophic factor (BDNF) is a small, basic protein purified from the mammalian brain that has been shown previously to support the survival of cultured spinal sensory neurons (Barde et al., 1982). In current studies, BDNF was tested for its ability to support the survival of cultured CNS cells isolated from the perinatal rat retina. Both immunofluorescent labeling of Thy-l and prior retrograde labeling with HRP were used as retinal ganglion cell markers in vitro. With embryonic day (E) 17 retinas, it was found that BDNF allowed the survival of a small subpopulation of neurons (about 7% of the cells plated at this age) identified by the immunofluorescent labeling of Thy-1. No detectable effects were seen when either the total number of cells or the number of tetanus toxin-positive neurons was measured. BDNF also had an effect on cultured neurons retrogradely labeled after HRP injections in the superior colliculi of neonatal rats. The BDNF-responsive population was therefore detected only in retinal cultures with specific markers and identified as consisting of retinal ganglion cells. These cells could be enriched about 80-fold by density gradient centrifugation, and purified ganglion cell cultures were shown to be responsive to BDNF. Whereas with El7 retinas, the number of surviving Thy-l positive neurons could be kept constant for at least 4 d, the survival of postnatal neurons was only transiently increased by BDNF.We conclude that in the retina, BDNF affects only the survival of ganglion cells in vitro by a direct action on these cells. The results are discussed in terms of target-derived neurotrophic support during development.The death of a substantial proportion of many different types of neurons is a common feature of the normal development of the vertebrate nervous system. It is generally believed to serve in the appropriate quantitative matching of a neuronal population with its respective terminal field .In vertebrates, evidence for the epigenetic regulation of neuronal cell death in the CNS as well as in the PNS has arisen from both target transplantation and ablation experiments. There is good evidence for molecular agents that serve to regulate neuronal cell death, the clearest being provided by the protein nerve growth factor (NGF). Treatment of developing mammals with antibodies against NGF results in the selective elimination of a large proportion of the peripheral sympathetic and sensory neurons. On the other hand, the treatment of animals with Received Jan. 7, 1986; revised Apr. 7, 1986; accepted Apr. 11, 1986. We wish to thank Dr. Hermann Rohrer for helpful suggestions and Mrs. C. Cap for technical assistance. This work was supported in part by fellowships from the Alexander von Humboldt Foundation, the Kempton Foundation and an NRSA from NIH, NINCDS (PHS-5F32-NSO7332-02X1) awarded to J.E.J.Correspondence should be addressed to Dr. James E. Thoenen and Barde, 1980). Results from in vitro assays have indicated that several other proteins with a similar function, but a differen...

Apoptotic cell death induced by optic nerve lesion in the neonatal rat

“…In accordance with this suicide program hypothesis, our in vivo experiments show that axotomy-induced degeneration is dependent on protein synthesis. Also consistent with this is the observation that NGF, as well as other neurotrophic factors, is critical for the survival of axotomized adult retinal ganglion cells both in vitro (Johnson et al, 1986;Thanos et al, 1989) and in vivo (Carmignoto et al, 1989;Mansour-Rabay et al, 1992;Mey and Thanos, 1993) as well as in neonatal rats (Rabacchi et al, 1992).…”

Contributions of the Optic Tectum and the Retina as Sources of Brain-Derived Neurotrophic Factor for Retinal Ganglion Cells in the Chick Embryo

“…Bennett, 1981). BDN F promotes the survival of RGC in vitro (Johnson et al, 1986;Rodríguez-Tébar et al, 1989;Thanos et al, 1989;Cohen-Cory and Fraser, 1994) and in vivo (Mey and Thanos, 1993;Mansour-Robaey et al, 1994;Unoki and LaVail, 1995;Weibel et al, 1995) [Voci et al (1993), as cited in Garner et al (1996)]. BDN F has been suggested to be a trophic factor derived from the tectum, and expression of BDN F mRNA in the tectum of several different species supports this hypothesis (Leibrock et al, 1989;Cohen-Cory and Fraser, 1994;).…”

“…RGC from all species that were examined respond to BDNF in vitro (Johnson et al, 1986;Rodríguez-Tébar et al, 1989;CohenCory and Fraser, 1994), but it is not known if BDN F acts in vivo as a target-derived factor or as a local retinal factor. Neurons in the SGFSi and SGC layers of the tectum receive innervation from RGC axons (Crossland et al, 1975;Repérant and Angaut, 1977).…”

“…Most retinal ganglion cells (RGC) degenerate after target removal or optic stalk transection in chicken (Hughes and LaVelle, 1975;Vanselow et al, 1990). RGC can be maintained by brain-derived neurotrophic factor (BDN F) in vitro (Johnson et al, 1986;Rodríguez-Tébar et al, 1989;Cohen-Cory and Fraser, 1994), and cells in the RGC layer express the BDNF receptor trkB (Okazawa et al, 1993(Okazawa et al, , 1995Perez and Caminos, 1995;Rickman and Brecha, 1995;Cohen-Cory et al, 1996;Garner et al, 1996;Hallböök et al, 1996). The expression of BDNF mRNA in target regions and its upregulation by physiological input further support the view that BDNF derived from the target plays a role in the maintenance of RGC (Castrén et al, 1992;Cohen-Cory and Fraser, 1994;Schoups et al, 1995) (for review, see von Bartheld, 1998a), but the retrograde transport of BDNF from the tectum to the retina has not been shown in the developing visual system.…”

The upregulation of GLAST-1 is an indirect antiapoptotic mechanism of GDNF and neurturin in the adult CNS

“…21 It is therefore surprising that GDNF rescues more than 14% of RGCs after axotomy and has additive effects with BDNF. 4 RGCs are known to be directly responsive to BDNF, 22 and therefore GDNF may prevent apoptosis by additional indirect mechanisms. One such mechanism may be the upregulation of glutamate transporters in surrounding glial cells, thereby enhancing extracellular glutamate uptake and reducing its excitotoxic effects on injured RGCs.…”