Objectives To study extracellular signal-regulated kinase (ERK) activation in the endometrial carcinoma cell line Ishikawa with stimulation by 17-β-estradiol, and to elucidate the role of phosphatase and tensin homol...Objectives To study extracellular signal-regulated kinase (ERK) activation in the endometrial carcinoma cell line Ishikawa with stimulation by 17-β-estradiol, and to elucidate the role of phosphatase and tensin homologue (PTEN) and estrogen receptor (ER) subtype on the activation of ERKs.Methods Western blot was used to examine the expression of PTEN and PTEN (G129E) in Ishikawa cells after stable transfection as well as ERK activation in Ishikawa-EGFP, Ishikawa- PTEN and Ishikawa- PTEN (G129E) stimulated with various doses of 17-β-estradiol for different lengths of time. Western blot was also used for examining the expression of ERα and ERβ in NIH3T3 fibroblasts after transient transfection of pCXN2hERα and pCXN2hERβ. Then, ERK activation was examined after stimulation with 17-β-estradiol. Results 17-β-estradiol activated ERK cascades (mainly ERK2) in Ishikawa cells. The activation of ERK increased gradually as concentration of 17-β-estradiol also increased. The maximal activation of ERK2 took place 5 min after stimulation with 17-β-estradiol. The activation of ERK2 was inhibited markedly by PTEN, but not by PTEN (G129E). 17-β-estradiol activated ERK cascades in NIH3T3 fibroblasts after transient transfection of pCXN2hERα.Conclusions 17-β-estradiol activate ERK cascades in Ishikawa cells by integrating with ERα. Lipid phosphatase PTEN has an inhibitory role on the activation of ERK stimulated by 17-β-estradiol in Ishikawa cells.展开更多
Environmental enrichment is known to be beneficial for cognitive improvement.In many animal models of neurological disorders and brain injury,EE has also demonstrated neuroprotective benefits in neurodegenerative dise...Environmental enrichment is known to be beneficial for cognitive improvement.In many animal models of neurological disorders and brain injury,EE has also demonstrated neuroprotective benefits in neurodegenerative diseases and in improving recovery after stroke or traumatic brain injury.The exact underlying mechanism for these phenomena has been unclear.Recent findings have now indicated that neuronal activity elicited by environmental enrichment induces Ca2+influx in dorsal root ganglion neurons results in lasting enhancement of CREB-binding protein-mediated histone acetylation.This,in turn,increases the expression of pro-regeneration genes and promotes axonal regeneration.This mechanism associated with neuronal activity elicited by environmental enrichment-mediated pathway is one of several epigenetic mechanisms which modulate axon regeneration upon injury that has recently come to light.The other prominent mechanisms,albeit not yet directly associated with environmental enrichment,include DNA methylation/demethylation and N6-methyladenosine modification of transcripts.In this brief review,I highlight recent work that has shed light on the epigenetic basis of environmental enrichment-based axon regeneration,and discuss the mechanism and pathways involved.I further speculate on the implications of the findings,in conjunction with the other epigenetic mechanisms,that could be harness to promote axon regeneration upon injury.展开更多
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 neur...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 SE＇I＇rlNG： 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 （M-I-F）, 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 in展开更多
基金ThisstudywassupportedbyagrantfromtheNationalNaturalScienceFoundationofChina (No 3 0 0 0 0 178)
文摘Objectives To study extracellular signal-regulated kinase (ERK) activation in the endometrial carcinoma cell line Ishikawa with stimulation by 17-β-estradiol, and to elucidate the role of phosphatase and tensin homologue (PTEN) and estrogen receptor (ER) subtype on the activation of ERKs.Methods Western blot was used to examine the expression of PTEN and PTEN (G129E) in Ishikawa cells after stable transfection as well as ERK activation in Ishikawa-EGFP, Ishikawa- PTEN and Ishikawa- PTEN (G129E) stimulated with various doses of 17-β-estradiol for different lengths of time. Western blot was also used for examining the expression of ERα and ERβ in NIH3T3 fibroblasts after transient transfection of pCXN2hERα and pCXN2hERβ. Then, ERK activation was examined after stimulation with 17-β-estradiol. Results 17-β-estradiol activated ERK cascades (mainly ERK2) in Ishikawa cells. The activation of ERK increased gradually as concentration of 17-β-estradiol also increased. The maximal activation of ERK2 took place 5 min after stimulation with 17-β-estradiol. The activation of ERK2 was inhibited markedly by PTEN, but not by PTEN (G129E). 17-β-estradiol activated ERK cascades in NIH3T3 fibroblasts after transient transfection of pCXN2hERα.Conclusions 17-β-estradiol activate ERK cascades in Ishikawa cells by integrating with ERα. Lipid phosphatase PTEN has an inhibitory role on the activation of ERK stimulated by 17-β-estradiol in Ishikawa cells.
基金supported by the National University of Singapore Graduate School for Integrative Sciences and Engineering(to BLT)
文摘Environmental enrichment is known to be beneficial for cognitive improvement.In many animal models of neurological disorders and brain injury,EE has also demonstrated neuroprotective benefits in neurodegenerative diseases and in improving recovery after stroke or traumatic brain injury.The exact underlying mechanism for these phenomena has been unclear.Recent findings have now indicated that neuronal activity elicited by environmental enrichment induces Ca2+influx in dorsal root ganglion neurons results in lasting enhancement of CREB-binding protein-mediated histone acetylation.This,in turn,increases the expression of pro-regeneration genes and promotes axonal regeneration.This mechanism associated with neuronal activity elicited by environmental enrichment-mediated pathway is one of several epigenetic mechanisms which modulate axon regeneration upon injury that has recently come to light.The other prominent mechanisms,albeit not yet directly associated with environmental enrichment,include DNA methylation/demethylation and N6-methyladenosine modification of transcripts.In this brief review,I highlight recent work that has shed light on the epigenetic basis of environmental enrichment-based axon regeneration,and discuss the mechanism and pathways involved.I further speculate on the implications of the findings,in conjunction with the other epigenetic mechanisms,that could be harness to promote axon regeneration upon injury.
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 SE＇I＇rlNG： 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 （M-I-F）, 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 in
