Previous studies have shown that transplanted enteric glia enhance axonal regeneration, reduce tissue damage, and promote functional recovery following spinal cord injury. However, the mechanisms by which enteric glia...Previous studies have shown that transplanted enteric glia enhance axonal regeneration, reduce tissue damage, and promote functional recovery following spinal cord injury. However, the mechanisms by which enteric glia mediate these beneficial effects are unknown. Neurotrophic factors can promote neuronal differentiation, survival and neurite extension. We hypothesized that enteric glia may exert their protective effects against spinal cord injury partially through the secretion of neurotrophic factors. In the present study, we demonstrated that primary enteric glia cells release nerve growth factor, brain-derived neurotrophic factor and glial cell line-derived neurotrophic factor over time with their concentrations reaching approximately 250, 100 and 50 pg/mL of culture medium respectively after 48 hours. The biological relevance of this secretion was assessed by incubating dissociated dorsal root ganglion neuronal cultures in enteric glia-conditioned medium with and/or without neutralizing antibodies to each of these proteins and evaluating the differences in neurite growth. We discovered that conditioned medium enhances neurite outgrowth in dorsal root ganglion neurons. Even though there was no detectable amount of neurotrophin-3 secretion using ELISA analysis, the neurite outgrowth effect can be attenuated by the antibody-mediated neutralization of each of the aforementioned neurotrophic factors. Therefore, enteric glia secrete nerve growth factor, brain-derived neurotrophic factor, glial cell line-derived neurotrophic factor and neurotrophin-3 into their surrounding environment in concentrations that can cause a biological effect.展开更多
Neurotrophin-3 (NT3) is a growth factor found in many body tissues including the heart, intestines, skin, nervous system and in skeletal muscles including muscle spindles (Murase et al., 1994). NT3 is required for the...Neurotrophin-3 (NT3) is a growth factor found in many body tissues including the heart, intestines, skin, nervous system and in skeletal muscles including muscle spindles (Murase et al., 1994). NT3 is required for the survival, correct connectivity and function of sensory (“proprioceptive”) afferents that innervate muscle spindles;these neurons express receptors for NT3 including tropomyocin receptor kinase C. These proprioceptive afferents are important for normal movement (Boyce and Mendell, 2014) and signals from muscle spindles are important for recovery of limb movement (e.g., after spinal cord lateral hemisection)(Takeoka et al., 2014). The level of NT3 declines in most tissues during postnatal development;its level is low in adult and elderly humans and other mammals (Murase et al., 1994). Elevation of NT3 has been shown to improve outcome in various animal models of neurological disease and injury. For example, many groups have shown that delivery of NT3 directly into the central nervous system promotes recovery after spinal cord injury but this often involved invasive routes or gene therapy (Boyce and Mendell, 2014;Petrosyan et al., 2015;Wang et al., 2018).展开更多
Aim:Previous studies show enteric glia(EG)-conditioned medium promotes neurite outgrowth in adult dorsal root ganglia(DRG)derived sensory neurons.This EG-conditioned medium contains various neurotrophic factors,includ...Aim:Previous studies show enteric glia(EG)-conditioned medium promotes neurite outgrowth in adult dorsal root ganglia(DRG)derived sensory neurons.This EG-conditioned medium contains various neurotrophic factors,including nerve growth factor(NGF),brain-derived neurotrophic factor(BDNF),glial cell line-derived neurotropic factor(GDNF),and neurotrophin-3(NT-3).This study attempts to determine the importance of these neurotrophic factors in enabling DRG-derived sensory neuron axons to overcome the inhibitory guidance cues released from the glial scar.Methods:A Semaphorin 3A(SEMA3A)growth cone collapse model was used on cultured rat DRG.Neutralizing antibodies to each neurotrophic growth factor in question(NGF,BDNF,GDNF and NT-3)were applied to the EG-conditioned medium to evaluate the factor’s individual importance in preventing growth cone collapse.Results:EG-conditioned medium inhibits and reverses growth cone collapse in adult DRG neurons when added either 1 h before or concurrently with SEMA3A.When administered 40 min after the initial SEMA3A-induced collapse,EG-conditioned medium was able to reverse the growth cone collapse.Individual inhibition of all the neurotrophic factors,except for BDNF in the co-treatment setting,resulted in increased growth cone collapse.Conclusion:NGF,BDNF,GDNF,and NT-3 are all variably involved in preventing or reversing SEMA3A-induced growth cone collapse in pre-,co-,and post-treatment time settings.However,no individual neurotrophic factors appear to be essential to promoting neurite outgrowth.展开更多
基金supported by Canadian Spinal Research Organization, No. #84831
文摘Previous studies have shown that transplanted enteric glia enhance axonal regeneration, reduce tissue damage, and promote functional recovery following spinal cord injury. However, the mechanisms by which enteric glia mediate these beneficial effects are unknown. Neurotrophic factors can promote neuronal differentiation, survival and neurite extension. We hypothesized that enteric glia may exert their protective effects against spinal cord injury partially through the secretion of neurotrophic factors. In the present study, we demonstrated that primary enteric glia cells release nerve growth factor, brain-derived neurotrophic factor and glial cell line-derived neurotrophic factor over time with their concentrations reaching approximately 250, 100 and 50 pg/mL of culture medium respectively after 48 hours. The biological relevance of this secretion was assessed by incubating dissociated dorsal root ganglion neuronal cultures in enteric glia-conditioned medium with and/or without neutralizing antibodies to each of these proteins and evaluating the differences in neurite growth. We discovered that conditioned medium enhances neurite outgrowth in dorsal root ganglion neurons. Even though there was no detectable amount of neurotrophin-3 secretion using ELISA analysis, the neurite outgrowth effect can be attenuated by the antibody-mediated neutralization of each of the aforementioned neurotrophic factors. Therefore, enteric glia secrete nerve growth factor, brain-derived neurotrophic factor, glial cell line-derived neurotrophic factor and neurotrophin-3 into their surrounding environment in concentrations that can cause a biological effect.
基金funded by the Brain Research Trust,the Rosetrees Trust and the International Spinal Research Trusta grant from the European Research Council under the European Union’s Seventh Framework Programme(FP/2007-2013)+5 种基金ERC Grant Agreement n.309731by a Research Councils UK Academic Fellowshipby the Medical Research Council(MRC)and the British Pharmacological Society(BPS)’s Integrative Pharmacology Fundsupported by the Dowager Countess Eleanor Peel Trusta Capacity Building Award in Integrative Mammalian Biology funded by the Biotechnology and Biological Sciences Research Council,BPSHigher Education Funding Council for England,Knowledge Transfer Partnerships,MRC and Scottish Funding Council
文摘Neurotrophin-3 (NT3) is a growth factor found in many body tissues including the heart, intestines, skin, nervous system and in skeletal muscles including muscle spindles (Murase et al., 1994). NT3 is required for the survival, correct connectivity and function of sensory (“proprioceptive”) afferents that innervate muscle spindles;these neurons express receptors for NT3 including tropomyocin receptor kinase C. These proprioceptive afferents are important for normal movement (Boyce and Mendell, 2014) and signals from muscle spindles are important for recovery of limb movement (e.g., after spinal cord lateral hemisection)(Takeoka et al., 2014). The level of NT3 declines in most tissues during postnatal development;its level is low in adult and elderly humans and other mammals (Murase et al., 1994). Elevation of NT3 has been shown to improve outcome in various animal models of neurological disease and injury. For example, many groups have shown that delivery of NT3 directly into the central nervous system promotes recovery after spinal cord injury but this often involved invasive routes or gene therapy (Boyce and Mendell, 2014;Petrosyan et al., 2015;Wang et al., 2018).
基金supported by Canadian Spinal Research Organization#84831.
文摘Aim:Previous studies show enteric glia(EG)-conditioned medium promotes neurite outgrowth in adult dorsal root ganglia(DRG)derived sensory neurons.This EG-conditioned medium contains various neurotrophic factors,including nerve growth factor(NGF),brain-derived neurotrophic factor(BDNF),glial cell line-derived neurotropic factor(GDNF),and neurotrophin-3(NT-3).This study attempts to determine the importance of these neurotrophic factors in enabling DRG-derived sensory neuron axons to overcome the inhibitory guidance cues released from the glial scar.Methods:A Semaphorin 3A(SEMA3A)growth cone collapse model was used on cultured rat DRG.Neutralizing antibodies to each neurotrophic growth factor in question(NGF,BDNF,GDNF and NT-3)were applied to the EG-conditioned medium to evaluate the factor’s individual importance in preventing growth cone collapse.Results:EG-conditioned medium inhibits and reverses growth cone collapse in adult DRG neurons when added either 1 h before or concurrently with SEMA3A.When administered 40 min after the initial SEMA3A-induced collapse,EG-conditioned medium was able to reverse the growth cone collapse.Individual inhibition of all the neurotrophic factors,except for BDNF in the co-treatment setting,resulted in increased growth cone collapse.Conclusion:NGF,BDNF,GDNF,and NT-3 are all variably involved in preventing or reversing SEMA3A-induced growth cone collapse in pre-,co-,and post-treatment time settings.However,no individual neurotrophic factors appear to be essential to promoting neurite outgrowth.
