We evaluated the effect of AAV2- and 17-AAG (17-N-allylamino-17-demethoxygeldanamycin)-mediated u... more We evaluated the effect of AAV2- and 17-AAG (17-N-allylamino-17-demethoxygeldanamycin)-mediated upregulation of Hsp70 expression on the survival of retinal ganglion cells (RGCs) injured by optic nerve crush (ONC). AAV2-Hsp70 expression in the retina was primarily observed in the ganglion cell layer. Approximately 75% of all transfected cells were RGCs. RGC survival in AAV2-Hsp70-injected animals was increased by an average of 110% 2 weeks after the axonal injury compared with the control. The increase in cell numbers was not even across the retinas with a maximum effect of approximately 306% observed in the inferior quadrant. 17-AAG-mediated induction of Hsp70 expression has been associated with cell protection in various models of neurodegenerative diseases. We show here that a single intravitreal injection of 17-AAG (0.2 ug ul(-1)) results in an increased survival of ONC-injured RGCs by approximately 49% compared with the vehicle-treated animals. Expression of Hsp70 in retinas of ...
Ciliary neurotrophic factor (CNTF) has been tested in clinical trials for human retinal degenerat... more Ciliary neurotrophic factor (CNTF) has been tested in clinical trials for human retinal degeneration due to its potent neuroprotective effects in various animal models. To decipher CNTF-triggered molecular events in the degenerating retina, we performed high-throughput RNA sequencing analyses using the Rds/Prph2 (P216L) transgenic mouse as a preclinical model for retinitis pigmentosa. In the absence of CNTF treatment, transcriptome alterations were detected at the onset of rod degeneration compared with wild type mice, including reduction of key photoreceptor transcription factors Crx, Nrl, and rod phototransduction genes. Short-term CNTF treatments caused further declines of photoreceptor transcription factors accompanied by marked decreases of both rod- and cone-specific gene expression. In addition, CNTF triggered acute elevation of transcripts in the innate immune system and growth factor signaling. These immune responses were sustained after long-term CNTF exposures that also a...
Members of the ciliary neurotrophic factor (CNTF) family of cytokines have been shown to influenc... more Members of the ciliary neurotrophic factor (CNTF) family of cytokines have been shown to influence neuronal differentiation during retinal development and enhance cell survival in various retinal degeneration models. However, the cellular mechanism of CNTF signaling and the target cell types for CNTF in the developing retina remain unidentified. The purpose of this study is to characterize expression patterns of proteins involved in cytokine signal transduction in the mouse retina, thus to assess the potential responsiveness of different retinal cell types to CNTF-like cytokine signals. The expression profiles of various cytokine signal transduction components, including receptor subunits CNTF receptor alpha (CNTFRa) and gp130, intracellular protein kinases, Jak2 and Tyk2, as well as latent transcription factors, STAT1 and STAT3, were determined by immunohistochemical staining of mouse retinal sections derived from different postnatal stages. In addition, the distribution of ERK was...
Ciliary neurotrophic factor (CNTF) exhibits multiple biological effects during vertebrate retinog... more Ciliary neurotrophic factor (CNTF) exhibits multiple biological effects during vertebrate retinogenesis, including regulation of photoreceptor cell differentiation. In the early postnatal mouse retina, CNTF induces rapid and transient phosphorylation of signal transducer and activator of transcription (STAT) 1 and STAT3 and the extracellular signal-regulated kinase (ERK). Although both proliferating progenitor cells and postmitotic neurons respond directly to cytokine signals, CNTF elicits distinct phosphorylation patterns of STAT3 and ERK. CNTF stimulation induces low levels of STAT3 phosphorylation in progenitors and differentiated neurons but a robust STAT3 activation among postmitotic photoreceptor precursors expressing the cone-rod homeobox geneCrxand newly differentiated rod photoreceptors. In contrast, CNTF causes preferential phosphorylation of ERK in progenitor cells and photoreceptor precursors. Inhibition of the cytokine receptor gp130 using neutralizing antibodies reveal...
Ciliary neurotrophic factor (CNTF) acts as a potent neuroprotective cytokine in multiple models o... more Ciliary neurotrophic factor (CNTF) acts as a potent neuroprotective cytokine in multiple models of retinal degeneration. To understand mechanisms underlying its broad neuroprotective effects, we have investigated the influence of CNTF on metabolism in a mouse model of photoreceptor degeneration. CNTF treatment improves the morphology of photoreceptor mitochondria, but also leads to reduced oxygen consumption and suppressed respiratory chain activities. Molecular analyses show elevated glycolytic pathway gene transcripts and active enzymes. Metabolomics analyses detect significantly higher levels of ATP and the energy currency phosphocreatine, elevated glycolytic pathway metabolites, increased TCA cycle metabolites, lipid biosynthetic pathway intermediates, nucleotides, and amino acids. Moreover, CNTF treatment restores the key antioxidant glutathione to the wild type level. Therefore, CNTF significantly impacts the metabolic status of degenerating retinas by promoting aerobic glycol...
ABSTRACTCiliary neurotrophic factor (CNTF) has potent neuroprotective activity in retinal degener... more ABSTRACTCiliary neurotrophic factor (CNTF) has potent neuroprotective activity in retinal degeneration animal models, yet the cellular mechanisms underlying its broad neuronal survival effects remain unclear. Here, we investigated the impact of CNTF on retinal metabolism in a mouse model of human retinitis pigmentosa. CNTF treatment resulted in improved mitochondrial morphology in mutant rod photoreceptors, but also led to reduced oxygen consumption and suppression of respiratory chain complex activities. Metabolomics analyses detected significantly higher levels of ATP and the energy currency phospho-creatine post CNTF exposure. In addition, CNTF-treated retinas contained elevated glycolytic metabolites and showed increased expression of genes and active enzymes of the glycolytic pathway. Metabolomics analyses also revealed increased TCA cycle products, lipid biosynthetic pathway intermediates, nucleotides, and amino acids, indicating an overall CNTF-dependent augmentation of anabo...
To characterize molecular and cellular changes induced by sustained expression of ciliary neurotr... more To characterize molecular and cellular changes induced by sustained expression of ciliary neurotrophic factor (CNTF) in the rds mutant mouse retina. Recombinant adeno-associated virus (rAAV) expressing CNTF was injected subretinally, for transduction of peripherin/rds(+/)(-) transgenic mice that carry the P216L mutation found in human retinitis pigmentosa. Characterization of retinal neurons and glia was performed by immunocytochemistry with cell-type-specific markers. Activation of signaling molecules was examined by Western blot and immunostaining. Alterations of gene transcription profiles were studied by microarray analyses. CNTF viral transduction maintained rhodopsin expression in surviving rod photoreceptors, but greatly reduced both S- and M-opsin normally expressed in cones. In addition, CNTF treatment resulted in increased numbers and dispersion of Müller glia and Chx10-positive bipolar cells within the inner nuclear layer. Persistent CNTF signaling also caused enhanced phosphorylation of STAT1, STAT3, and p42/44 ERK, as well as their levels of expression. Moreover, altered transcription profiles were detected for a large number of genes. Among these, Crx and Nrl involved in photoreceptor differentiation and several genes involved in phototransduction were suppressed. Despite the rescue from cell death, continuous exposure to CNTF changed photoreceptor cell profiles, especially resulting in the loss of cone immunoreactivity. In addition, the Müller glia and bipolar cells became disorganized, and the number of cells expressing Müller and bipolar cell markers increased. Constitutive CNTF production resulted in sustained activation of cytokine signal transduction and altered the expression of a large number of genes. Therefore, stringent regulation of CNTF may be necessary for its therapeutic application in preventing retinal degeneration.
We evaluated the effect of AAV2- and 17-AAG (17-N-allylamino-17-demethoxygeldanamycin)-mediated u... more We evaluated the effect of AAV2- and 17-AAG (17-N-allylamino-17-demethoxygeldanamycin)-mediated upregulation of Hsp70 expression on the survival of retinal ganglion cells (RGCs) injured by optic nerve crush (ONC). AAV2-Hsp70 expression in the retina was primarily observed in the ganglion cell layer. Approximately 75% of all transfected cells were RGCs. RGC survival in AAV2-Hsp70-injected animals was increased by an average of 110% 2 weeks after the axonal injury compared with the control. The increase in cell numbers was not even across the retinas with a maximum effect of approximately 306% observed in the inferior quadrant. 17-AAG-mediated induction of Hsp70 expression has been associated with cell protection in various models of neurodegenerative diseases. We show here that a single intravitreal injection of 17-AAG (0.2 ug ul(-1)) results in an increased survival of ONC-injured RGCs by approximately 49% compared with the vehicle-treated animals. Expression of Hsp70 in retinas of ...
Ciliary neurotrophic factor (CNTF) has been tested in clinical trials for human retinal degenerat... more Ciliary neurotrophic factor (CNTF) has been tested in clinical trials for human retinal degeneration due to its potent neuroprotective effects in various animal models. To decipher CNTF-triggered molecular events in the degenerating retina, we performed high-throughput RNA sequencing analyses using the Rds/Prph2 (P216L) transgenic mouse as a preclinical model for retinitis pigmentosa. In the absence of CNTF treatment, transcriptome alterations were detected at the onset of rod degeneration compared with wild type mice, including reduction of key photoreceptor transcription factors Crx, Nrl, and rod phototransduction genes. Short-term CNTF treatments caused further declines of photoreceptor transcription factors accompanied by marked decreases of both rod- and cone-specific gene expression. In addition, CNTF triggered acute elevation of transcripts in the innate immune system and growth factor signaling. These immune responses were sustained after long-term CNTF exposures that also a...
Members of the ciliary neurotrophic factor (CNTF) family of cytokines have been shown to influenc... more Members of the ciliary neurotrophic factor (CNTF) family of cytokines have been shown to influence neuronal differentiation during retinal development and enhance cell survival in various retinal degeneration models. However, the cellular mechanism of CNTF signaling and the target cell types for CNTF in the developing retina remain unidentified. The purpose of this study is to characterize expression patterns of proteins involved in cytokine signal transduction in the mouse retina, thus to assess the potential responsiveness of different retinal cell types to CNTF-like cytokine signals. The expression profiles of various cytokine signal transduction components, including receptor subunits CNTF receptor alpha (CNTFRa) and gp130, intracellular protein kinases, Jak2 and Tyk2, as well as latent transcription factors, STAT1 and STAT3, were determined by immunohistochemical staining of mouse retinal sections derived from different postnatal stages. In addition, the distribution of ERK was...
Ciliary neurotrophic factor (CNTF) exhibits multiple biological effects during vertebrate retinog... more Ciliary neurotrophic factor (CNTF) exhibits multiple biological effects during vertebrate retinogenesis, including regulation of photoreceptor cell differentiation. In the early postnatal mouse retina, CNTF induces rapid and transient phosphorylation of signal transducer and activator of transcription (STAT) 1 and STAT3 and the extracellular signal-regulated kinase (ERK). Although both proliferating progenitor cells and postmitotic neurons respond directly to cytokine signals, CNTF elicits distinct phosphorylation patterns of STAT3 and ERK. CNTF stimulation induces low levels of STAT3 phosphorylation in progenitors and differentiated neurons but a robust STAT3 activation among postmitotic photoreceptor precursors expressing the cone-rod homeobox geneCrxand newly differentiated rod photoreceptors. In contrast, CNTF causes preferential phosphorylation of ERK in progenitor cells and photoreceptor precursors. Inhibition of the cytokine receptor gp130 using neutralizing antibodies reveal...
Ciliary neurotrophic factor (CNTF) acts as a potent neuroprotective cytokine in multiple models o... more Ciliary neurotrophic factor (CNTF) acts as a potent neuroprotective cytokine in multiple models of retinal degeneration. To understand mechanisms underlying its broad neuroprotective effects, we have investigated the influence of CNTF on metabolism in a mouse model of photoreceptor degeneration. CNTF treatment improves the morphology of photoreceptor mitochondria, but also leads to reduced oxygen consumption and suppressed respiratory chain activities. Molecular analyses show elevated glycolytic pathway gene transcripts and active enzymes. Metabolomics analyses detect significantly higher levels of ATP and the energy currency phosphocreatine, elevated glycolytic pathway metabolites, increased TCA cycle metabolites, lipid biosynthetic pathway intermediates, nucleotides, and amino acids. Moreover, CNTF treatment restores the key antioxidant glutathione to the wild type level. Therefore, CNTF significantly impacts the metabolic status of degenerating retinas by promoting aerobic glycol...
ABSTRACTCiliary neurotrophic factor (CNTF) has potent neuroprotective activity in retinal degener... more ABSTRACTCiliary neurotrophic factor (CNTF) has potent neuroprotective activity in retinal degeneration animal models, yet the cellular mechanisms underlying its broad neuronal survival effects remain unclear. Here, we investigated the impact of CNTF on retinal metabolism in a mouse model of human retinitis pigmentosa. CNTF treatment resulted in improved mitochondrial morphology in mutant rod photoreceptors, but also led to reduced oxygen consumption and suppression of respiratory chain complex activities. Metabolomics analyses detected significantly higher levels of ATP and the energy currency phospho-creatine post CNTF exposure. In addition, CNTF-treated retinas contained elevated glycolytic metabolites and showed increased expression of genes and active enzymes of the glycolytic pathway. Metabolomics analyses also revealed increased TCA cycle products, lipid biosynthetic pathway intermediates, nucleotides, and amino acids, indicating an overall CNTF-dependent augmentation of anabo...
To characterize molecular and cellular changes induced by sustained expression of ciliary neurotr... more To characterize molecular and cellular changes induced by sustained expression of ciliary neurotrophic factor (CNTF) in the rds mutant mouse retina. Recombinant adeno-associated virus (rAAV) expressing CNTF was injected subretinally, for transduction of peripherin/rds(+/)(-) transgenic mice that carry the P216L mutation found in human retinitis pigmentosa. Characterization of retinal neurons and glia was performed by immunocytochemistry with cell-type-specific markers. Activation of signaling molecules was examined by Western blot and immunostaining. Alterations of gene transcription profiles were studied by microarray analyses. CNTF viral transduction maintained rhodopsin expression in surviving rod photoreceptors, but greatly reduced both S- and M-opsin normally expressed in cones. In addition, CNTF treatment resulted in increased numbers and dispersion of Müller glia and Chx10-positive bipolar cells within the inner nuclear layer. Persistent CNTF signaling also caused enhanced phosphorylation of STAT1, STAT3, and p42/44 ERK, as well as their levels of expression. Moreover, altered transcription profiles were detected for a large number of genes. Among these, Crx and Nrl involved in photoreceptor differentiation and several genes involved in phototransduction were suppressed. Despite the rescue from cell death, continuous exposure to CNTF changed photoreceptor cell profiles, especially resulting in the loss of cone immunoreactivity. In addition, the Müller glia and bipolar cells became disorganized, and the number of cells expressing Müller and bipolar cell markers increased. Constitutive CNTF production resulted in sustained activation of cytokine signal transduction and altered the expression of a large number of genes. Therefore, stringent regulation of CNTF may be necessary for its therapeutic application in preventing retinal degeneration.
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Papers by Kun Do Rhee