BACKGROUND: Nerve growth factor (NGF) attenuates glutamate-induced injury to hippocampal neurons, and the human tumor suppressor gene phosphatase and tensin homologue deleted on chromosome 10 (PTEN) promotes neuronal ...BACKGROUND: Nerve growth factor (NGF) attenuates glutamate-induced injury to hippocampal neurons, and the human tumor suppressor gene phosphatase and tensin homologue deleted on chromosome 10 (PTEN) promotes neuronal apoptosis. However, effects of PTEN in NGF-mediated neuroprotection against glutamate excitotoxicity remain poorly understood. OBJECTIVE: To investigate the relationship between NGF inhibition of glutamate-induced injury and PTEN. DESIGN, TIME AND SETTING: The randomized, controlled, in vitro study was performed at the Department of Pathophysiology, Medical School of Nantong University, China from October 2007 to March 2008. MATERIALS: Glutamate, NGF, 4, 6-diamidino-2-phenyl-indolediacetate, 3-[4, 5-dimethylthiazol-2-yl]- 2, 5-diphenyl tetrazoliumbromide (MTT), and lactate dehydrogenase kit (Sigma, USA), fluorescence microscope and inverted phase contrast microscope (Olympus, Japan) were used in this study. METHODS: Hippocampal neurons were obtained from newborn (< 24 hours) Sprague Dawley rats and cultured for 7 days. The control group was not treated with any intervention factor, the glutamate group was treated with glutamate (0.2 mmol/L), and NGF groups were treated with NGF (10, 50, 100, and 200 μg/L, respectively) prior to glutamate treatment. MAIN OUTCOME MEASURES: The MTT and lactate dehydrogenase assays were applied to evaluate viability of hippocampal neurons. Morphological changes in hippocampal neurons were observed using an inverted phase-contrast microscope, and neuronal apoptosis was detected by 4, 6-diamidino-2-phenyl-indolediacetate staining. PTEN mRNA and protein expression were measured by reverse transcription-polymerase chain reaction and Western blot analysis, respectively. RESULTS: Glutamate (0.2 mmol/L) induced significantly decreased neuronal viability and greater lactate dehydrogenase efflux compared with the control group (P < 0.01). However, compared with the glutamate group, cell viability significantly increased and lactate dehydrogenase efflux decreased in the NGF group with increasing NGF concentrations (P < 0.05 or P < 0.01). The apoptotic ratio and PTEN mRNA and protein expression decreased in the NGF group compared with the glutamate group (P < 0.01). CONCLUSION: Pretreatment with NGF exerted neuroprotective effects against glutamate-induced injury, partially through inhibition of PTEN expression and neuronal apoptosis.展开更多
Studies have shown that phosphatase and tensin homolog deleted on chromosome ten(PTEN)participates in the regulation of cochlear hair cell survival.Bisperoxovanadium protects against neurodegeneration by inhibiting PT...Studies have shown that phosphatase and tensin homolog deleted on chromosome ten(PTEN)participates in the regulation of cochlear hair cell survival.Bisperoxovanadium protects against neurodegeneration by inhibiting PTEN expression.However,whether bisperoxovanadium can protect against noise-induced hearing loss and the underlying mechanism remains unclear.In this study,we established a mouse model of noise-induced hearing loss by exposure to 105 dB sound for 2 hours.We found that PTEN expression was increased in the organ of Corti,including outer hair cells,inner hair cells,and lateral wall tissues.Intraperitoneal administration of bisperoxovanadium decreased the auditory threshold and the loss of cochlear hair cells and inner hair cell ribbons.In addition,noise exposure decreased p-PI3K and p-Akt levels.Bisperoxovanadium preconditioning or PTEN knockdown upregulated the activity of PI3K-Akt.Bisperoxovanadium also prevented H_(2)O_(2)-induced hair cell death by reducing mitochondrial reactive oxygen species generation in cochlear explants.These findings suggest that bisperoxovanadium reduces noise-induced hearing injury and reduces cochlear hair cell loss.展开更多
基金the Natural Science Foundation of Jiangsu Province, No. BK2004048the Social Development and Technology Plan of Nantong City, No. K2008009
文摘BACKGROUND: Nerve growth factor (NGF) attenuates glutamate-induced injury to hippocampal neurons, and the human tumor suppressor gene phosphatase and tensin homologue deleted on chromosome 10 (PTEN) promotes neuronal apoptosis. However, effects of PTEN in NGF-mediated neuroprotection against glutamate excitotoxicity remain poorly understood. OBJECTIVE: To investigate the relationship between NGF inhibition of glutamate-induced injury and PTEN. DESIGN, TIME AND SETTING: The randomized, controlled, in vitro study was performed at the Department of Pathophysiology, Medical School of Nantong University, China from October 2007 to March 2008. MATERIALS: Glutamate, NGF, 4, 6-diamidino-2-phenyl-indolediacetate, 3-[4, 5-dimethylthiazol-2-yl]- 2, 5-diphenyl tetrazoliumbromide (MTT), and lactate dehydrogenase kit (Sigma, USA), fluorescence microscope and inverted phase contrast microscope (Olympus, Japan) were used in this study. METHODS: Hippocampal neurons were obtained from newborn (< 24 hours) Sprague Dawley rats and cultured for 7 days. The control group was not treated with any intervention factor, the glutamate group was treated with glutamate (0.2 mmol/L), and NGF groups were treated with NGF (10, 50, 100, and 200 μg/L, respectively) prior to glutamate treatment. MAIN OUTCOME MEASURES: The MTT and lactate dehydrogenase assays were applied to evaluate viability of hippocampal neurons. Morphological changes in hippocampal neurons were observed using an inverted phase-contrast microscope, and neuronal apoptosis was detected by 4, 6-diamidino-2-phenyl-indolediacetate staining. PTEN mRNA and protein expression were measured by reverse transcription-polymerase chain reaction and Western blot analysis, respectively. RESULTS: Glutamate (0.2 mmol/L) induced significantly decreased neuronal viability and greater lactate dehydrogenase efflux compared with the control group (P < 0.01). However, compared with the glutamate group, cell viability significantly increased and lactate dehydrogenase efflux decreased in the NGF group with increasing NGF concentrations (P < 0.05 or P < 0.01). The apoptotic ratio and PTEN mRNA and protein expression decreased in the NGF group compared with the glutamate group (P < 0.01). CONCLUSION: Pretreatment with NGF exerted neuroprotective effects against glutamate-induced injury, partially through inhibition of PTEN expression and neuronal apoptosis.
基金supported by the National Natural Science Foundation of China,Nos.81670925(to FQC),81870732(to DJZ),81800918(to WL),81900933(to YLS)Department of Science and Technology Key Industry Innovation Chain Social Development Field Fund of Shaanxi Province,No.2021ZDLSF02-12(to FQC)the Natural Science Foundation of Shaanxi Province,No.2019JM-009(to JC).
文摘Studies have shown that phosphatase and tensin homolog deleted on chromosome ten(PTEN)participates in the regulation of cochlear hair cell survival.Bisperoxovanadium protects against neurodegeneration by inhibiting PTEN expression.However,whether bisperoxovanadium can protect against noise-induced hearing loss and the underlying mechanism remains unclear.In this study,we established a mouse model of noise-induced hearing loss by exposure to 105 dB sound for 2 hours.We found that PTEN expression was increased in the organ of Corti,including outer hair cells,inner hair cells,and lateral wall tissues.Intraperitoneal administration of bisperoxovanadium decreased the auditory threshold and the loss of cochlear hair cells and inner hair cell ribbons.In addition,noise exposure decreased p-PI3K and p-Akt levels.Bisperoxovanadium preconditioning or PTEN knockdown upregulated the activity of PI3K-Akt.Bisperoxovanadium also prevented H_(2)O_(2)-induced hair cell death by reducing mitochondrial reactive oxygen species generation in cochlear explants.These findings suggest that bisperoxovanadium reduces noise-induced hearing injury and reduces cochlear hair cell loss.
