ORCID Profile
0000-0001-9689-4085
Current Organisation
Universidade Federal do Rio de Janeiro Instituto de Biofísica Carlos Chagas Filho
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Publisher: Wiley
Date: 12-12-2001
DOI: 10.1002/NEU.10008
Abstract: Neuronal survival in the vertebrate peripheral nervous system depends on neurotrophic factors available from target tissues. In an attempt to identify novel survival factors, we have studied the effect of secreted factors from retinal cells on the survival of chick sympathetic ganglion neurons. Embryonic day 10 sympathetic neurons undergo programmed cell death after 48 h without appropriate levels of nerve growth factor (NGF). Retina Conditioned Media (RCM) from explants of embryonic day 11 retinas maintained for 4 days in vitro supported 90% of E10 chick sympathetic neurons after 48 h. Conditioned medium from purified chick retinal Muller glial cells supported nearly 100% of E10 chick sympathetic neurons. Anti-NGF (1 microg/mL) blocked the survival effect of NGF, but did not block the trophic effect of RCM. Neither BDNF nor NT4 (0.1-50 ng/mL) supported E10 sympathetic neuron survival. Incubation of chimeric immunoglobulin-receptors TrkA, TrkB, or TrkC had no effect on RCM-induced sympathetic neuron survival. The survival effects were not blocked by anti-GDNF, anti-TGFbeta, and anti-CNTF and were not mimicked by FGFb (0.1-10 nM). LY294002 at 50 microM, but not PD098059 blocked sympathetic survival induced by RCM. Further, the combination of RCM and NGF did not result in an increase in neuronal survival compared with NGF alone (82% survival after 48 h). The secreted factor in RCM is retained in subfractions with a molecular weight above 100 kDa, binds to heparin, and is unaffected by dialysis, but is heat sensitive. Our results indicate the presence of a high-molecular weight retinal secreted factor that supports sympathetic neurons in culture.
Publisher: Elsevier BV
Date: 03-2009
DOI: 10.1016/J.NEUROSCIENCE.2008.12.059
Abstract: A rat model of complete sciatic nerve transection was used to evaluate the effect of bone marrow mononuclear cells (BMMC) transplanted to the injury site immediately after lesion. Rats treated with BMMC had both sensory and motor axons reaching the distal stump earlier compared to untreated animals. In addition, BMMC transplantation reduced cell death in dorsal root ganglia (DRG) compared to control animals. Transplanted BMMC remained in the lesion site for several days but there is no evidence of BMMC differentiation into Schwann cells. However, an increase in the number of Schwann cells, satellite cells and astrocytes was observed in the treated group. Moreover, neutralizing antibodies for nerve growth factor (NGF) (but not for brain-derived neurotrophic factor and ciliary-derived neurotrophic factor) added to the BMMC-conditioned medium reduced neurite growth of sensory and sympathetic neurons in vitro, suggesting that BMMC release NGF, improve regeneration of the sciatic nerve in the adult rat and stimulate Schwann and satellite cell proliferation or a combination of both.
Publisher: Elsevier BV
Date: 11-2019
Publisher: Elsevier BV
Date: 04-2008
DOI: 10.1016/J.BRAINRES.2008.02.035
Abstract: We have examined the trophic effects of conditioned media obtained from purified murine Müller glia cells on chick purified sympathetic or dorsal root ganglia (DRG) neurons and on Retinal Ganglion Cells (RGC) from postnatal mice. Purified murine Müller glia cultures stained positively for vimentin, GFAP or S-100, but were negative for neuronal markers. Murine Müller glial conditioned medium (MMG) was concentrated and at 1:1 dilution supported 100% survival of chick or rat sympathetic neurons after 48 h compared to 80%, 96 h) compared to laminin+poly-L-lysine substrates. In conclusion, we show that purified mice Müller glia cultures secrete NGF that support peripheral neuronal survival and other unidentified trophic molecules that induce RGC survival and neuritogenesis.
Publisher: Elsevier BV
Date: 07-2007
DOI: 10.1016/J.NEURES.2007.03.010
Abstract: Methylmercury (MeHg) is related to several deleterious effects on the vertebrate nervous system and part of these effects are through interaction with sulfhydryl (-SH) group found in cellular proteins. We decided to characterize the dose-dependent effect of MeHg on the neurotoxicity and the neurite outgrowth induced effects on chick sympathetic neurons dissociated and purified in culture. In this model, MeHg inhibited neurite outgrowth (1-10 microM) and induced cell death (1-10 microM) after 48 h in culture. Since metal toxicity often generates reactive oxygen species, we tested if antioxidant compounds such as glutathione (GSH) or L-cysteine (L-cys) could block the deleterious effects promoted by MeHg. L-methionine, another sulfur-containing amino acid, but without a SH group, was also used in this work. We show that GSH (10-100 microM) and L-cys (100 microM), but not L-methionine (100 microM), fully blocked neurite degeneration and sympathetic neuron cell death in culture.
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 12-2003
DOI: 10.1097/00001756-200312190-00022
Abstract: We have examined how herbimycin affects the survival and neuritogenesis of avian sympathetic neurons. Herbimycin promoted sympathetic neuron survival and neuritogenesis. At higher concentrations (> or = 100 ng/ml), herbimycin still enhanced neuron survival but blocked neuritogenesis. Addition of herbimycin (10-30 ng/ml) to neurons cultured in the presence of NGF or retinal conditioned medium altered neuronal morphology, with an increase in the number of neurites. Addition of NGF during hypoxia rescued 52% of the neurons compared to 14% survival in control conditions. Herbimycin alone rescued about 50% of the neurons. In the presence of NGF and 100 ng/ml herbimycin, 81% of the neurons survived hypoxia. Our results show that herbimycin promotes survival of chick sympathetic neurons and potentiates the effects of NGF.
Location: Brazil
Location: United Kingdom of Great Britain and Northern Ireland
Location: Brazil
No related grants have been discovered for Ricardo Augusto de Melo Reis.