RESUMEN
Glucocorticoid-induced glaucoma is a secondary open-angle glaucoma. About 40% of the general population may develop elevated intraocular pressure on prolonged glucocorticoid treatment secondary to damages in the trabecular meshwork (TM), a tissue that regulates intraocular pressure. Therefore, identifying the key molecules responsible for glucocorticoid-induced ocular hypertension is crucial. In this study, Dickkopf-related protein 1 (Dkk1), a canonical Wnt signaling inhibitor, was found to be elevated in the aqueous humor and TM of glaucoma patients. At the signaling level, Dkk1 enhanced glucocorticoid receptor (GR) signaling, whereas Dkk1 knockdown or Wnt signaling activators decreased GR signaling in human TM cells as indicated by luciferase assays. Similarly, activation of the GR signaling inhibited Wnt signaling. At the protein level, glucocorticoid-induced extracellular matrix was inhibited by Wnt activation using Wnt activators or Dkk1 knockdown in primary human TM cells. In contrast, inhibition of canonical Wnt signaling by ß-catenin knockdown increased glucocorticoid-induced extracellular matrix proteins. At the physiological level, adenovirus-mediated Wnt3a expression decreased glucocorticoid-induced ocular hypertension in mouse eyes. In summary, Wnt and GR signaling inhibit each other in the TM, and canonical Wnt signaling activators may prevent the adverse effect of glucocorticoids in the eye.
Asunto(s)
Glaucoma/metabolismo , Receptores de Glucocorticoides/metabolismo , Malla Trabecular/metabolismo , Vía de Señalización Wnt/fisiología , Animales , Femenino , Glaucoma/inducido químicamente , Glucocorticoides/efectos adversos , Humanos , Inmunosupresores/efectos adversos , Ratones , Ratones Endogámicos C57BLRESUMEN
Optic neuropathies are a group of optic nerve (ON) diseases caused by various insults including glaucoma, inflammation, ischemia, trauma, and genetic deficits, which are characterized by retinal ganglion cell (RGC) death and ON degeneration. An increasing number of genes involved in RGC intrinsic signaling have been found to be promising neural repair targets that can potentially be modulated directly by gene therapy, if we can achieve RGC specific gene targeting. To address this challenge, we first used adeno-associated virus (AAV)-mediated gene transfer to perform a low-throughput in vivo screening in both male and female mouse eyes and identified the mouse γ-synuclein (mSncg) promoter, which specifically and potently sustained transgene expression in mouse RGCs and also works in human RGCs. We further demonstrated that gene therapy that combines AAV-mSncg promoter with clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 gene editing can knock down pro-degenerative genes in RGCs and provide effective neuroprotection in optic neuropathies.SIGNIFICANCE STATEMENT Here, we present an RGC-specific promoter, mouse γ-synuclein (mSncg) promoter, and perform extensive characterization and proof-of-concept studies of mSncg promoter-mediated gene expression and clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 gene editing in RGCs in vivo To our knowledge, this is the first report demonstrating in vivo neuroprotection of injured RGCs and optic nerve (ON) by AAV-mediated CRISPR/Cas9 inhibition of genes that are critical for neurodegeneration. It represents a powerful tool to achieve RGC-specific gene modulation, and also opens up a promising gene therapy strategy for optic neuropathies, the most common form of eye diseases that cause irreversible blindness.
Asunto(s)
Regulación de la Expresión Génica/genética , Edición de ARN/genética , Células Ganglionares de la Retina/metabolismo , gamma-Sinucleína/genética , Animales , Sistemas CRISPR-Cas , Dependovirus/genética , Femenino , Eliminación de Gen , Terapia Genética , Humanos , Células Madre Pluripotentes Inducidas , Masculino , Ratones , Ratones Endogámicos C57BL , Nervio Óptico/patología , Enfermedades del Nervio Óptico/genética , Enfermedades del Nervio Óptico/terapia , Células Ganglionares de la Retina/patología , Transgenes/genéticaRESUMEN
BACKGROUND: The use of clinical MRI scanners to conduct pre-clinical research facilitates comparisons with clinical studies. Here the utility and sensitivity of anatomical and functional MRI data/biomarkers acquired from transgenic mouse models of neuroblastoma using a dedicated radiofrequency (RF) coil on a clinical 3T scanner was evaluated. METHODS: Multiparametric MRI of transgenic mice bearing abdominal neuroblastomas was performed at 3T, and data cross-referenced to that acquired from the same mice on a pre-clinical 7T MRI system. T2-weighted imaging, quantitation of the native longitudinal relaxation time (T1) and the transverse relaxation rate (R2*), and dynamic contrast-enhanced (DCE)-MRI, was used to assess tumour volume, phenotype and response to cyclophosphamide or cabozantinib. RESULTS: Excellent T2-weighted image contrast enabled clear tumour delineation at 3T. Significant correlations of tumour volume (R=0.98, P<0.0001) and R2* (R=0.87, P<0.002) measured at 3 and 7T were established. Mice with neuroblastomas harbouring the anaplastic lymphoma kinase mutation exhibited a significantly slower R2* (P<0.001), consistent with impaired tumour perfusion. DCE-MRI was performed simultaneously on three transgenic mice, yielding estimates of Ktrans for each tumour (median Ktrans values of 0.202, 0.168 and 0.114 min-1). Cyclophosphamide elicited a significant reduction in both tumour burden (P<0.002) and native T1 (P<0.01), whereas cabozantinib induced significant (P<0.01) tumour growth delay. CONCLUSIONS: Simultaneous multiparametric MRI of multiple tumour-bearing animals using this coil arrangement at 3T can provide high efficiency/throughput for both phenotypic characterisation and evaluation of novel therapeutics, and facilitate the introduction of functional MRI biomarkers into aligned imaging-embedded clinical trials.
Asunto(s)
Imagen por Resonancia Magnética/métodos , Imanes , Neuroblastoma/diagnóstico por imagen , Neoplasias Gástricas/diagnóstico por imagen , Quinasa de Linfoma Anaplásico , Anilidas/uso terapéutico , Animales , Antineoplásicos/uso terapéutico , Medios de Contraste , Ciclofosfamida/uso terapéutico , Modelos Animales de Enfermedad , Femenino , Imagen por Resonancia Magnética/instrumentación , Masculino , Ratones , Ratones Transgénicos , Mutación , Proteína Proto-Oncogénica N-Myc/metabolismo , Neuroblastoma/tratamiento farmacológico , Neuroblastoma/genética , Neuroblastoma/patología , Fantasmas de Imagen , Fenotipo , Piridinas/uso terapéutico , Proteínas Tirosina Quinasas Receptoras/genética , Relación Señal-Ruido , Neoplasias Gástricas/tratamiento farmacológico , Neoplasias Gástricas/genética , Neoplasias Gástricas/patología , Carga Tumoral/efectos de los fármacosRESUMEN
Primary Open Angle Glaucoma (POAG) is an irreversible, vision-threatening disease that affects millions worldwide. The principal risk factor of POAG is increased intraocular pressure (IOP) due to pathological changes in the trabecular meshwork (TM). The TGFß signaling pathway activator TGFß2 and the Wnt signaling pathway inhibitor secreted frizzled-related protein 1 (sFRP1) are elevated in the POAG TM. In this study, we determined whether there is a crosstalk between the TGFß/Smad pathway and the canonical Wnt pathway using luciferase reporter assays. Lentiviral luciferase reporter vectors for studying the TGFß/Smad pathway or the canonical Wnt pathway were transduced into primary human non-glaucomatous TM (NTM) cells. Cells were treated with or without a combination of 5 µg/ml TGFß2 and/or 100 ng/ml Wnt3a recombinant proteins, and luciferase levels were measured using a plate reader. We found that TGFß2 inhibited Wnt3a-induced canonical Wnt pathway activation, while Wnt3a inhibited TGFß2-induced TGFß/Smad pathway activation (n = 6, p < 0.05) in 3 NTM cell strains. We also found that knocking down of Smad4 or ß-catenin using siRNA in HTM5 cells transfected with similar luciferase reporter plasmids abolished the inhibitory effect of TGFß2 and/or Wnt3a on the other pathway (n = 6). Our results suggest the existence of a cross-inhibition between the TGFß/Smad and canonical Wnt pathways in the TM, and this cross-inhibition may be mediated by Smad4 and ß-catenin.
Asunto(s)
Glaucoma de Ángulo Abierto/metabolismo , Malla Trabecular/metabolismo , Factor de Crecimiento Transformador beta2/fisiología , Vía de Señalización Wnt/fisiología , Proteína Wnt3A/fisiología , Anciano , Anciano de 80 o más Años , Western Blotting , Femenino , Humanos , Luciferasas/metabolismo , Masculino , Transducción de Señal/fisiología , Proteína Smad4/metabolismo , Factor de Crecimiento Transformador beta2/metabolismo , Factor de Crecimiento Transformador beta2/farmacología , Proteína Wnt3A/metabolismo , Proteína Wnt3A/farmacología , beta Catenina/metabolismoRESUMEN
Optineurin (OPTN) mutations are linked to amyotrophic lateral sclerosis (ALS) and normal tension glaucoma (NTG), but a relevant animal model is lacking, and the molecular mechanisms underlying neurodegeneration are unknown. We found that OPTN C-terminus truncation (OPTN∆C) causes late-onset neurodegeneration of retinal ganglion cells (RGCs), optic nerve (ON), and spinal cord motor neurons, preceded by a striking decrease of axonal mitochondria. Surprisingly, we discover that OPTN directly interacts with both microtubules and the mitochondrial transport complex TRAK1/KIF5B, stabilizing them for proper anterograde axonal mitochondrial transport, in a C-terminus dependent manner. Encouragingly, overexpressing OPTN/TRAK1/KIF5B reverses not only OPTN truncation-induced, but also ocular hypertension-induced neurodegeneration, and promotes striking ON regeneration. Therefore, in addition to generating new animal models for NTG and ALS, our results establish OPTN as a novel facilitator of the microtubule-dependent mitochondrial transport necessary for adequate axonal mitochondria delivery, and its loss as the likely molecular mechanism of neurodegeneration.
RESUMEN
MYCN oncogene amplification is frequently observed in aggressive childhood neuroblastoma. Using an unbiased large-scale mutagenesis screen in neuroblastoma-prone transgenic mice, we identify a single germline point mutation in the transcriptional corepressor Runx1t1, which abolishes MYCN-driven tumorigenesis. This loss-of-function mutation disrupts a highly conserved zinc finger domain within Runx1t1. Deletion of one Runx1t1 allele in an independent Runx1t1 knockout mouse model is also sufficient to prevent MYCN-driven neuroblastoma development, and reverse ganglia hyperplasia, a known pre-requisite for tumorigenesis. Silencing RUNX1T1 in human neuroblastoma cells decreases colony formation in vitro, and inhibits tumor growth in vivo. Moreover, RUNX1T1 knockdown inhibits the viability of PAX3-FOXO1 fusion-driven rhabdomyosarcoma and MYC-driven small cell lung cancer cells. Despite the role of Runx1t1 in MYCN-driven tumorigenesis neither gene directly regulates the other. We show RUNX1T1 forms part of a transcriptional LSD1-CoREST3-HDAC repressive complex recruited by HAND2 to enhancer regions to regulate chromatin accessibility and cell-fate pathway genes.
Asunto(s)
Carcinogénesis , Proteína Proto-Oncogénica N-Myc , Neuroblastoma , Animales , Humanos , Ratones , Carcinogénesis/genética , Línea Celular Tumoral , Proteínas Co-Represoras/metabolismo , Proteínas Co-Represoras/genética , Regulación Neoplásica de la Expresión Génica , Histona Demetilasas/metabolismo , Histona Demetilasas/genética , Ratones Noqueados , Ratones Transgénicos , Proteína Proto-Oncogénica N-Myc/genética , Proteína Proto-Oncogénica N-Myc/metabolismo , Neuroblastoma/genética , Neuroblastoma/metabolismo , Neuroblastoma/patología , Factores de Transcripción/metabolismo , Factores de Transcripción/genéticaRESUMEN
PURPOSE: To evaluate noninvasive and clinically translatable magnetic resonance (MR) imaging biomarkers of therapeutic response in the TH-MYCN transgenic mouse model of aggressive, MYCN-amplified neuroblastoma. MATERIALS AND METHODS: All experiments were performed in accordance with the local ethical review panel and the UK Home Office Animals Scientific Procedures Act 1986 and with the UK National Cancer Research Institute guidelines for the welfare of animals in cancer research. Multiparametric MR imaging was performed of abdominal tumors found in the TH-MYCN model. T2-weighted MR imaging, quantitation of native relaxation times T1 and T2, the relaxation rate R2*, and dynamic contrast-enhanced MR imaging were used to monitor tumor response to cyclophosphamide (25 mg/kg), the vascular disrupting agent ZD6126 (200 mg/kg), or the antiangiogenic agent cediranib (6 mg/kg, daily). Any significant changes in the measured parameters, and in the magnitude of the changes after treatment between treated and control cohorts, were identified by using Student two-tailed paired and unpaired t test, respectively, with a 5% level of significance. RESULTS: Treatment with cyclophosphamide or cediranib induced a 54% or 20% reduction in tumor volume at 48 hours, respectively (P < .005 and P < .005, respectively; P < .005 and P < .005 versus control, respectively). Treatment with ZD6126 induced a 45% reduction in mean tumor volume 24 hours after treatment (P < .005; P < .005 versus control). The antitumor activity of cyclophosphamide, cediranib, and ZD6126 was consistently associated with a decrease in tumor T1 (P < .005, P < .005, and P < .005, respectively; P < .005, P < .005, and P < .005 versus control, respectively) and with a correlation between therapy-induced changes in native T1 and changes in tumor volume (r = 0.56; P < .005). Tumor response to cediranib was also associated with a decrease in the dynamic contrast-enhanced MR imaging-derived volume transfer constant (P = .07; P < .05 versus control) and enhancing fraction (P < .05; P < .01 versus control), and an increase in R2* (P < .005; P < .05 versus control). CONCLUSION: The T1 relaxation time is a robust noninvasive imaging biomarker of response to therapy in tumors in TH-MYCN mice, which emulate high-risk neuroblastoma in children. T1 measurements can be readily implemented on clinical MR systems and should be investigated in translational clinical trials of new targeted therapies for pediatric neuroblastoma. SUPPLEMENTAL MATERIAL: http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.12120128/-/DC1.
Asunto(s)
Antineoplásicos/uso terapéutico , Modelos Animales de Enfermedad , Neuroblastoma/tratamiento farmacológico , Neuroblastoma/patología , Animales , Biomarcadores , Humanos , Imagen por Resonancia Magnética , Ratones , Ratones Transgénicos , Proteína Proto-Oncogénica N-Myc , Pronóstico , Proteínas Proto-Oncogénicas/genética , Reproducibilidad de los Resultados , Sensibilidad y Especificidad , Resultado del TratamientoRESUMEN
Recently, we established silicone oil-induced ocular hypertension (SOHU) mouse model with significant glaucomatous neurodegeneration. Here we characterize two additional variations of this model that simulate two distinct glaucoma types. The first is a chronic model produced by high frequency (HF) pupillary dilation after SO-induced pupillary block, which shows sustained moderate IOP elevation and corresponding slow, mild glaucomatous neurodegeneration. We also demonstrate that although SO removal quickly returns IOP to normal, the glaucomatous neurodegeneration continues to advance to a similar degree as in the HF group without SO removal. The second, an acute model created by no pupillary dilation (ND), shows a greatly elevated IOP and severe inner retina degeneration at an early time point. Therefore, by a straightforward dilation scheme, we extend our original SOHU model to recapitulate phenotypes of two major glaucoma forms, which will be invaluable for selecting neuroprotectants and elucidating their molecular mechanisms.
Asunto(s)
Modelos Animales de Enfermedad , Glaucoma/patología , Hipertensión Ocular/fisiopatología , Degeneración Retiniana/patología , Células Ganglionares de la Retina/patología , Aceites de Silicona/toxicidad , Enfermedad Aguda , Animales , Femenino , Glaucoma/inducido químicamente , Presión Intraocular , Masculino , Ratones , Ratones Endogámicos C57BL , Hipertensión Ocular/inducido químicamente , Degeneración Retiniana/inducido químicamente , Células Ganglionares de la Retina/efectos de los fármacos , Aceites de Silicona/administración & dosificaciónRESUMEN
The impressive functions of the brain rely on an extensive connectivity matrix between specific neurons, the architecture of which is frequently characterized by one brain nucleus/region connecting to multiple targets, either via collaterals of the same projection neuron or several, differentially specified neurons. Delineating the fine architecture of projection neuron subsets in a specific brain region could greatly facilitate its circuit, computational, and functional resolution. Here, we developed multiple fluorescent rabies viruses (RV) to delineate the fine organization of corticothalamic projection neuron subsets in the primary visual cortex (V1). By simultaneously retrograde labeling multiple distinct subsets of corticothalamic projection neurons in V1 from their target nuclei in thalamus (dLGN, LP, LD), we observed that V1-dLGN corticothalamic projection neurons were densely concentrated in layer VI, except for several sparsely scattered neurons in layer V, while V1-LP and V1-LD corticothalamic projection neurons were localized to both layers V and VI. Meanwhile, we observed a fraction of V1 corticothalamic projection neurons targeting two thalamic nuclei, which was further confirmed by fMOST whole-brain imaging. The multiple fluorescent RV tracing tools can be extensively applied to resolve the architecture of projection neuron subsets in certain brain regions, with a strong potential to delineate the computational and functional organization of these brain regions.
Asunto(s)
Virus de la Rabia , Corteza Visual , Interneuronas , Rabia , Tálamo/diagnóstico por imagenRESUMEN
Loss-of-function mutations in both alleles of the human insulin receptor gene (INSR) cause extreme insulin resistance (IR) and usually death in childhood, with few effective therapeutic options. Bivalent antireceptor antibodies can elicit insulin-like signaling by mutant INSR in cultured cells, but whether this translates into meaningful metabolic benefits in vivo, wherein the dynamics of insulin signaling and receptor recycling are more complex, is unknown. To address this, we adopted a strategy to model human insulin receptoropathy in mice, using Cre recombinase delivered by adeno-associated virus to knockout endogenous hepatic Insr acutely in floxed Insr mice (liver insulin receptor knockout [L-IRKO] + GFP), before adenovirus-mediated add back of wild-type (WT) or mutant human INSR Two murine anti-INSR monoclonal antibodies, previously shown to be surrogate agonists for mutant INSR, were then tested by intraperitoneal injections. As expected, L-IRKO + GFP mice showed glucose intolerance and severe hyperinsulinemia. This was fully corrected by add back of WT but not with either D734A or S350L mutant INSR. Antibody injection improved glucose tolerance in D734A INSR-expressing mice and reduced hyperinsulinemia in both S350L and D734A INSR-expressing animals. It did not cause hypoglycemia in WT INSR-expressing mice. Antibody treatment also downregulated both WT and mutant INSR protein, attenuating its beneficial metabolic effects. Anti-INSR antibodies thus improve IR in an acute model of insulin receptoropathy, but these findings imply a narrow therapeutic window determined by competing effects of antibodies to stimulate receptors and induce their downregulation.
Asunto(s)
Anticuerpos , Modelos Animales de Enfermedad , Hiperglucemia/terapia , Insulina/inmunología , Receptor de Insulina/inmunología , Receptor de Insulina/metabolismo , Animales , Glucemia , Regulación de la Expresión Génica , Hígado/metabolismo , Masculino , Ratones , Ratones Noqueados , ARN Mensajero/genética , ARN Mensajero/metabolismo , Distribución Aleatoria , Receptor de Insulina/genéticaRESUMEN
The antimetabolite 6-mercaptopurine (6-MP) is an important component in the treatment of specific cancer subtypes, however, the development of drug resistance and dose-limiting toxicities can limit its effectiveness. The therapeutic activity of 6-MP requires cellular uptake, enzymatic conversion to thio-GMP and incorporation of thio-GTP into RNA and DNA, as well as inhibition of de novo purine synthesis by methyl-thio-IMP. Mechanisms that prevent 6-MP entry into the cell, prevent 6-MP metabolism or deplete thiopurine intermediates, can all lead to 6-MP resistance. We previously conducted a high-throughput screen for inhibitors of the multidrug transporter MRP4 using 6-MP sensitivity as the readout. In addition to MRP4-specific inhibitors, we identified a compound, CCI52, that sensitized cell lines to 6-MP independent of this transporter. CCI52 and its more stable analogue CCI52-14 also function as effective chemosensitizers in vivo, substantially extending survival in a transgenic mouse cancer model treated with 6-MP. Chemosensitization was associated with an increase in thio-IMP, suggesting that CCI52 functions directly on 6-MP uptake or metabolism. In addition to its chemosensitizing effects, CCI52 and CCI52-14 inhibited the growth of MYCN-amplified high-risk neuroblastoma cell lines and delayed tumor progression in a MYCN-driven, transgenic mouse model of neuroblastoma. These multifunctional inhibitors may be useful for the further development of anticancer agents and as tools to better understand 6-MP metabolism.
Asunto(s)
Antimetabolitos Antineoplásicos/uso terapéutico , Mercaptopurina/administración & dosificación , Mercaptopurina/farmacología , Neuroblastoma/tratamiento farmacológico , Tiazoles/farmacología , Animales , Antimetabolitos Antineoplásicos/administración & dosificación , Línea Celular Tumoral , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Humanos , Ratones , Ratones Transgénicos , Estructura Molecular , Proteína Proto-Oncogénica N-Myc/genética , Proteína Proto-Oncogénica N-Myc/metabolismo , Neoplasias Experimentales/tratamiento farmacológico , Neuroblastoma/patología , Tiazoles/efectos adversos , Tiazoles/químicaRESUMEN
The undruggable nature of oncogenic Myc transcription factors poses a therapeutic challenge in neuroblastoma, a pediatric cancer in which MYCN amplification is strongly associated with unfavorable outcome. Here, we show that CYC065 (fadraciclib), a clinical inhibitor of CDK9 and CDK2, selectively targeted MYCN-amplified neuroblastoma via multiple mechanisms. CDK9 - a component of the transcription elongation complex P-TEFb - bound to the MYCN-amplicon superenhancer, and its inhibition resulted in selective loss of nascent MYCN transcription. MYCN loss led to growth arrest, sensitizing cells for apoptosis following CDK2 inhibition. In MYCN-amplified neuroblastoma, MYCN invaded active enhancers, driving a transcriptionally encoded adrenergic gene expression program that was selectively reversed by CYC065. MYCN overexpression in mesenchymal neuroblastoma was sufficient to induce adrenergic identity and sensitize cells to CYC065. CYC065, used together with temozolomide, a reference therapy for relapsed neuroblastoma, caused long-term suppression of neuroblastoma growth in vivo, highlighting the clinical potential of CDK9/2 inhibition in the treatment of MYCN-amplified neuroblastoma.
Asunto(s)
Adenosina/análogos & derivados , Quinasa 2 Dependiente de la Ciclina/antagonistas & inhibidores , Quinasa 9 Dependiente de la Ciclina/antagonistas & inhibidores , Proteína Proto-Oncogénica N-Myc/biosíntesis , Neuroblastoma/tratamiento farmacológico , Temozolomida/farmacología , Adenosina/farmacología , Línea Celular Tumoral , Quinasa 2 Dependiente de la Ciclina/metabolismo , Quinasa 9 Dependiente de la Ciclina/metabolismo , Elementos de Facilitación Genéticos , Humanos , Proteína Proto-Oncogénica N-Myc/genética , Neuroblastoma/genética , Neuroblastoma/metabolismo , Neuroblastoma/patología , Factor B de Elongación Transcripcional Positiva/genética , Factor B de Elongación Transcripcional Positiva/metabolismo , Transcripción Genética/efectos de los fármacosRESUMEN
Elevated intraocular pressure (IOP) is a well-documented risk factor for glaucoma. Here we describe a novel, effective method for consistently inducing stable IOP elevation in mice that mimics the post-operative complication of using silicone oil (SO) as a tamponade agent in human vitreoretinal surgery. In this protocol, SO is injected into the anterior chamber of the mouse eye to block the pupil and prevent inflow of aqueous humor. The posterior chamber accumulates aqueous humor and this in turn increases the IOP of the posterior segment. A single SO injection produces reliable, sufficient, and stable IOP elevation, which induces significant glaucomatous neurodegeneration. This model is a true replicate of secondary glaucoma in the eye clinic. To further mimic the clinical setting, SO can be removed from the anterior chamber to reopen the drainage pathway and allow inflow of aqueous humor, which is drained through the trabecular meshwork (TM) at the angle of the anterior chamber. Because IOP quickly returns to normal, the model can be used to test the effect of lowering IOP on glaucomatous retinal ganglion cells. This method is straightforward, does not require special equipment or repeat procedures, closely simulates clinical situations, and may be applicable to diverse animal species. However, minor modifications may be required.
Asunto(s)
Modelos Animales de Enfermedad , Hipertensión Ocular/inducido químicamente , Hipertensión Ocular/patología , Silicio/toxicidad , Animales , Humor Acuoso/efectos de los fármacos , Humor Acuoso/fisiología , Inyecciones Intraoculares , Presión Intraocular/efectos de los fármacos , Presión Intraocular/fisiología , Masculino , Ratones , Ratones Endogámicos C57BL , Aceites/administración & dosificación , Aceites/toxicidad , Células Ganglionares de la Retina/efectos de los fármacos , Células Ganglionares de la Retina/patología , Células Ganglionares de la Retina/fisiología , Silicio/administración & dosificaciónRESUMEN
Understanding the molecular mechanism of glaucoma and development of neuroprotectants is significantly hindered by the lack of a reliable animal model that accurately recapitulates human glaucoma. Here, we sought to develop a mouse model for the secondary glaucoma that is often observed in humans after silicone oil (SO) blocks the pupil or migrates into the anterior chamber following vitreoretinal surgery. We observed significant intraocular pressure (IOP) elevation after intracameral injection of SO, and that SO removal allows IOP to return quickly to normal. This simple, inducible and reversible mouse ocular hypertension model shows dynamic changes of visual function that correlate with progressive retinal ganglion cell (RGC) loss and axon degeneration. It may be applicable with only minor modifications to a range of animal species in which it will generate stable, robust IOP elevation and significant neurodegeneration that will facilitate selection of neuroprotectants and investigating the pathogenesis of ocular hypertension-induced glaucoma.
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Modelos Animales de Enfermedad , Glaucoma/patología , Enfermedades Neurodegenerativas/patología , Hipertensión Ocular/inducido químicamente , Hipertensión Ocular/complicaciones , Aceites de Silicona/efectos adversos , Animales , Supervivencia Celular/efectos de los fármacos , Inyecciones Intraoculares , Ratones , Células Ganglionares de la Retina/efectos de los fármacos , Células Ganglionares de la Retina/patología , Aceites de Silicona/administración & dosificaciónRESUMEN
Neuroblastoma is a pediatric cancer that is frequently metastatic and resistant to conventional treatment. In part, a lack of natively metastatic, chemoresistant in vivo models has limited our insight into the development of aggressive disease. The Th-MYCN genetically engineered mouse model develops rapidly progressive chemosensitive neuroblastoma and lacks clinically relevant metastases. To study tumor progression in a context more reflective of clinical therapy, we delivered multicycle treatment with cyclophosphamide to Th-MYCN mice, individualizing therapy using MRI, to generate the Th-MYCN CPM32 model. These mice developed chemoresistance and spontaneous bone marrow metastases. Tumors exhibited an altered immune microenvironment with increased stroma and tumor-associated fibroblasts. Analysis of copy number aberrations revealed genomic changes characteristic of human MYCN-amplified neuroblastoma, specifically copy number gains at mouse chromosome 11, syntenic with gains on human chromosome 17q. RNA sequencing revealed enriched expression of genes associated with 17q gain and upregulation of genes associated with high-risk neuroblastoma, such as the cell-cycle regulator cyclin B1-interacting protein 1 (Ccnb1ip1) and thymidine kinase (TK1). The antiapoptotic, prometastatic JAK-STAT3 pathway was activated in chemoresistant tumors, and treatment with the JAK1/JAK2 inhibitor CYT387 reduced progression of chemoresistant tumors and increased survival. Our results highlight that under treatment conditions that mimic chemotherapy in human patients, Th-MYCN mice develop genomic, microenvironmental, and clinical features reminiscent of human chemorefractory disease. The Th-MYCN CPM32 model therefore is a useful tool to dissect in detail mechanisms that drive metastasis and chemoresistance, and highlights dysregulation of signaling pathways such as JAK-STAT3 that could be targeted to improve treatment of aggressive disease. SIGNIFICANCE: An in vivo mouse model of high-risk treatment-resistant neuroblastoma exhibits changes in the tumor microenvironment, widespread metastases, and sensitivity to JAK1/2 inhibition.
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Antineoplásicos/uso terapéutico , Resistencia a Antineoplásicos , Genes myc , Metástasis de la Neoplasia/tratamiento farmacológico , Neuroblastoma/tratamiento farmacológico , Animales , Antineoplásicos/farmacología , Benzamidas/farmacología , Benzamidas/uso terapéutico , Niño , Ciclofosfamida/farmacología , Ciclofosfamida/uso terapéutico , Modelos Animales de Enfermedad , Progresión de la Enfermedad , Dosificación de Gen , Regulación Neoplásica de la Expresión Génica , Humanos , Quinasas Janus/antagonistas & inhibidores , Imagen por Resonancia Magnética , Ratones , Ratones Transgénicos , Proteína Proto-Oncogénica N-Myc/genética , Metástasis de la Neoplasia/diagnóstico por imagen , Proteínas de Neoplasias/antagonistas & inhibidores , Proteínas de Neoplasias/biosíntesis , Proteínas de Neoplasias/genética , Neuroblastoma/diagnóstico por imagen , Neuroblastoma/genética , Neuroblastoma/patología , Pirimidinas/farmacología , Pirimidinas/uso terapéutico , Transducción de Señal , Sintenía , Carga Tumoral , Microambiente TumoralRESUMEN
Purpose: Wnt/ß-catenin signaling in the trabecular meshwork (TM) is required for maintaining normal intraocular pressure (IOP), although the mechanism(s) behind this are unknown. We hypothesize that Wnt/ß-catenin signaling regulates IOP via ß-catenin's effects on cadherin junctions. Methods: Nonglaucomatous primary human TM (NTM) cells were treated with or without 100 ng/ml Wnt3a, 1 µg/ml sFRP1, or both for 4 to 48 hours. Cells were immunostained for ß-catenin, total cadherins, or cadherin isoforms. Membrane proteins or whole-cell lysates were isolated for Western immunoblotting and probed for cadherin isoforms. RNA was extracted for cDNA synthesis and qPCR analysis of cadherin expression. Some NTM cells were cultured on electric plates for cell impedance assays. Ad5.CMV recombinant adenoviruses encoding K-cadherin, and/or sFRP1 were injected into eyes of 4- to 6-month-old female BALB/cJ mice (n = 8-10). Conscious IOPs were assessed for 35 days. Results: Upon Wnt3a treatment, total cadherin expression increased and ß-catenin accumulated at the TM cell membrane and on processes formed between TM cells. qPCR showed that Wnt3a significantly increased K-cadherin expression in NTM cells (P < 0.01, n = 3), and Western immunoblotting showed that Wnt3a increased K-cadherin in NTM cells, which was inhibited by the addition of sFRP1. Cell impedance assays showed that Wnt3a treatment increased transcellular resistance and anti-K-cadherin siRNA decreased transcellular resistance (P < 0.001, n = 4-6). Our in vivo study showed that K-cadherin significantly decreased sFRP1-induced ocular hypertension (P < 0.05, n = 6). Western immunoblotting also showed that K-cadherin alleviated sFRP1-induced ß-catenin decrease in mouse anterior segments. Conclusions: Our results suggest that cadherins play important roles in the regulation of TM homeostasis and IOP via the Wnt/ß-catenin pathway.
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Cadherinas/fisiología , Presión Intraocular/fisiología , Malla Trabecular/efectos de los fármacos , Malla Trabecular/metabolismo , Vía de Señalización Wnt/fisiología , Proteína Wnt3A/farmacología , beta Catenina/fisiología , Animales , Western Blotting , Cadherinas/metabolismo , Membrana Celular/metabolismo , Células Cultivadas , Modelos Animales de Enfermedad , Femenino , Humanos , Ratones , Ratones Endogámicos BALB C , Isoformas de Proteínas/metabolismo , Transducción de Señal/fisiología , beta Catenina/metabolismoRESUMEN
Purpose: Increased intraocular pressure results from increased aqueous humor (AH) outflow resistance at the trabecular meshwork (TM) due to pathologic changes including the formation of cross-linked actin networks (CLANs). Transforming growth factor ß2 (TGFß2) is elevated in the AH and TM of primary open angle glaucoma (POAG) patients and induces POAG-associated TM changes, including CLANs. We determined the role of individual TGFß2 signaling pathways in CLAN formation. Methods: Cultured nonglaucomatous human TM (NTM) cells were treated with control or TGFß2, with or without the inhibitors of TGFß receptor, Smad3, c-Jun N-terminal kinases (JNK), extracellular signal regulated kinase (ERK), P38, or Rho-associated protein kinase (ROCK). NTM cells were cotreated with TGFß2 plus inhibitors for 10 days or pretreated with TGFß2 for 10 days followed by 1-hour inhibitor treatment. NTM cells were immunostained with phalloidin-Alexa-488 and 4',6-diamidino-2-phenylindole (DAPI). Data were analyzed using 1-way ANOVA and Dunnett's post hoc test. Results: TGFß2 significantly induced CLAN formation (n = 6 to 12, P < 0.05), which was completely inhibited by TGFß receptor, Smad3, and ERK inhibitors, as well as completely or partially inhibited by JNK, P38, and ROCK inhibitors, depending on cell strains. One-hour exposure to ROCK inhibitor completely resolved formed CLANs (P < 0.05), whereas TGFß receptor, Smad3 inhibitor, and ERK inhibitors resulted in partial or complete resolution. The JNK and P38 inhibitors showed partial or no resolution. Among these inhibitors, the ROCK inhibitor was the most disruptive to the actin stress fibers, whereas ERK inhibition showed the least disruption. Conclusions: TGFß2-induced CLANs in NTM cells were prevented and resolved using various pathway inhibitors. Apart from CLAN inhibition, some of these inhibitors also had different effects on actin stress fibers.
Asunto(s)
Actinas/metabolismo , Proteína smad3/metabolismo , Malla Trabecular/efectos de los fármacos , Factor de Crecimiento Transformador beta2/farmacología , Análisis de Varianza , Humor Acuoso/metabolismo , Western Blotting , Células Cultivadas , Humanos , Proteínas Quinasas JNK Activadas por Mitógenos/metabolismo , Proteínas Serina-Treonina Quinasas , Receptor Tipo II de Factor de Crecimiento Transformador beta , Receptores de Factores de Crecimiento Transformadores beta , Transducción de Señal/fisiología , Malla Trabecular/metabolismo , Factor de Crecimiento Transformador beta2/antagonistas & inhibidores , Factor de Crecimiento Transformador beta2/fisiologíaRESUMEN
The most common ocular side effect of glucocorticoid (GC) therapy is GC-induced ocular hypertension (OHT) and GC-induced glaucoma (GIG). GC-induced OHT occurs in about 40% of the general population, while the other 60% are resistant. This study aims to determine the genes and pathways involved in differential GC responsiveness in the trabecular meshwork (TM). Using paired bovine eyes, one eye was perfusion-cultured with 100nM dexamethasone (DEX), while the fellow eye was used to establish a bovine TM (BTM) cell strain. Based on maximum IOP change in the perfused eye, the BTM cell strain was identified as a DEX-responder or non-responder strain. Three responder and three non-responder BTM cell strains were cultured, treated with 0.1% ethanol or 100nM DEX for 7 days. RNA and proteins were extracted for RNA sequencing (RNAseq), qPCR, and Western immunoblotting (WB), respectively. Data were analyzed using the human and bovine genome databases as well as Tophat2 software. Genes were grouped and compared using Student's t-test. We found that DEX induced fibronectin expression in responder BTM cells but not in non-responder cells using WB. RNAseq showed between 93 and 606 differentially expressed genes in different expression groups between responder and non-responder BTM cells. The data generated by RNAseq were validated using qPCR. Pathway analyses showed 35 pathways associated with differentially expressed genes. These genes and pathways may play important roles in GC-induced OHT and will help us to better understand differential ocular responsiveness to GCs.
Asunto(s)
Regulación de la Expresión Génica/efectos de los fármacos , Glucocorticoides/farmacología , Malla Trabecular/citología , Transcriptoma , Animales , Bovinos , Biología Computacional/métodos , Perfilación de la Expresión Génica , Secuenciación de Nucleótidos de Alto Rendimiento , Mapeo de Interacción de Proteínas , Análisis de Secuencia de ARN , Transducción de Señal , Malla Trabecular/metabolismoRESUMEN
PURPOSE: Elevated intraocular pressure (IOP) in primary open-angle glaucoma (POAG) results from glaucomatous damage to the trabecular meshwork (TM). The glaucoma-associated factor TGFß2 is increased in aqueous humor and TM of POAG patients. We hypothesize that histone acetylation has a role in dysregulated TGFß2 expression. METHODS: Protein acetylation was compared between nonglaucomatous TM (NTM) and glaucomatous TM (GTM) cells using Western immunoblotting (WB). Nonglaucomatous TM cells were treated with 10 nM thailandepsin-A (TDP-A), a potent histone deacetylase inhibitor for 4 days. Total and nuclear proteins, RNA, and nuclear protein-DNA complexes were harvested for WB, quantitative PCR (qPCR), and chromatin immunoprecipitation (ChIP) assays, respectively. Paired bovine eyes were perfused with TDP-A versus DMSO, or TDP-A versus TDP-A plus the TGFß pathway inhibitor LY364947 for 5 to 9 days. Intraocular pressure, TM, and perfusate proteins were compared. RESULTS: We found increased acetylated histone 3 and total protein acetylation in the GTM cells and TDP-A treated NTM cells. Chromatin immunoprecipitation assays showed that TDP-A induced histone hyperacetylation associated with the TGFß2 promoter. This change of acetylation significantly increased TGFß2 mRNA and protein expression in NTM cells. In perfusion-cultured bovine eyes, TDP-A increased TGFß2 in the perfusate as well as elevated IOP. Histologic and immunofluorescent analyses showed increased extracellular matrix and cytoskeletal proteins in the TM of TDP-A treated bovine eyes. Cotreatment with the TGFß pathway inhibitor LY364947 blocked TDP-A-induced ocular hypertension. CONCLUSIONS: Our results suggest that histone acetylation has an important role in increased expression of the glaucoma-associated factor TGFß2. Histone hyperacetylation may be the initiator of glaucomatous damage to the TM.