RESUMO
Preterm birth is the leading cause of death in children under 5 years of age. Premature infants who receive life-saving oxygen therapy often develop bronchopulmonary dysplasia (BPD), a chronic lung disease. Infants with BPD are at a high risk of abnormal neurodevelopment, including motor and cognitive difficulties. While neural progenitor cells (NPCs) are crucial for proper brain development, it is unclear whether they play a role in BPD-associated neurodevelopmental deficits. Here, we show that hyperoxia-induced experimental BPD in newborn mice led to lifelong impairments in cerebrovascular structure and function as well as impairments in NPC self-renewal and neurogenesis. A neurosphere assay utilizing nonhuman primate preterm baboon NPCs confirmed impairment in NPC function. Moreover, gene expression profiling revealed that genes involved in cell proliferation, angiogenesis, vascular autoregulation, neuronal formation, and neurotransmission were dysregulated following neonatal hyperoxia. These impairments were associated with motor and cognitive decline in aging hyperoxia-exposed mice, reminiscent of deficits observed in patients with BPD. Together, our findings establish a relationship between BPD and abnormal neurodevelopmental outcomes and identify molecular and cellular players of neonatal brain injury that persist throughout adulthood that may be targeted for early intervention to aid this vulnerable patient population.
Assuntos
Displasia Broncopulmonar , Disfunção Cognitiva , Hiperóxia , Nascimento Prematuro , Recém-Nascido , Feminino , Camundongos , Humanos , Animais , Hiperóxia/complicações , Hiperóxia/metabolismo , Animais Recém-Nascidos , Displasia Broncopulmonar/genética , Neurogênese , Disfunção Cognitiva/etiologia , Cognição , Pulmão/metabolismoRESUMO
Retinal detachment is an acute disorder in humans that is caused by trauma or disease, and it can often lead to permanent visual deficits that result from the death of photoreceptors in the retina. The final pathway for photoreceptor cell death is apoptosis and necroptosis. The X-linked inhibitor of apoptosis (XIAP) has been shown to block both of these cell death pathways. This study tested the effects of XIAP on photoreceptor survival in a feline model of retinal detachment. The study was performed in 12 cats, divided into two experimental groups. Six animals received a subretinal injection of adeno-associated virus (AAV) carrying XIAP, and six animals received AAV carrying green fluorescent protein (GFP) as a control. Three weeks after viral delivery, retinas were detached by injecting C3F8 gas into the subretinal space. Optical coherence tomography revealed that the retinal detachments resolved within 3-6 weeks as the gas was slowly resorbed. Analysis of histological sections through the plane of the detachment showed significant preservation of the photoreceptor layer in AAV-XIAP-treated animals compared to AAV-GFP-treated animals at 9 weeks after the detachment. XIAP-treated detached retinas were similar to intact controls. These studies support the potential for XIAP therapy in the treatment of human retinal detachment.
Assuntos
Terapia Genética/métodos , Vetores Genéticos/metabolismo , Células Fotorreceptoras Retinianas Cones/metabolismo , Descolamento Retiniano/terapia , Proteínas Inibidoras de Apoptose Ligadas ao Cromossomo X/genética , Animais , Apoptose/genética , Gatos , Linhagem Celular , Dependovirus/genética , Dependovirus/metabolismo , Modelos Animais de Doenças , Fluorocarbonos/administração & dosagem , Expressão Gênica , Genes Reporter , Vetores Genéticos/administração & dosagem , Vetores Genéticos/química , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Humanos , Injeções Intraoculares , Células Fotorreceptoras Retinianas Cones/patologia , Descolamento Retiniano/genética , Descolamento Retiniano/metabolismo , Descolamento Retiniano/patologia , Transdução de Sinais , Tomografia de Coerência Óptica , Transgenes , Resultado do Tratamento , Proteínas Inibidoras de Apoptose Ligadas ao Cromossomo X/metabolismoRESUMO
PURPOSE: To evaluate the ability of X-linked inhibitor of apoptosis (XIAP) gene therapy to provide neuroprotection to cells of the outer nuclear layer (ONL) of the retina after retinal detachment. METHODS: Subretinal injections of a recombinant adenoassociated virus (rAAV) encoding either XIAP or green fluorescent protein (GFP; injection control) were performed in the left eye of Brown Norway rats. Two weeks later, retinal detachments were created at the site of viral injection by delivering sodium hyaluronate into the subretinal space. Retinal tissue was harvested at 24 hours after retinal detachment and was analyzed for caspase 3 and 9 activity. Histologic analysis was conducted on samples taken at 3 days and 2 months after detachment to confirm the presence of XIAP or GFP expression and to assess levels of apoptosis and changes in retinal thickness. RESULTS: Caspase assays performed 24 hours after detachment confirmed an expected increase in caspase 3 and 9 activity in the detached regions of GFP-treated retinas, whereas XIAP-treated detached retinas behaved comparably to attached controls. TUNEL analysis of 3-day tissue samples showed fewer apoptotic cells in XIAP-treated detachments than in GFP-treated detachments. At 2 months after the detachment, histology and immunohistochemistry confirmed the preservation of the ONL at sites of XIAP overexpression, whereas the GFP-treated detached retinas had significantly deteriorated. CONCLUSIONS: The results suggest that XIAP confers structural neuroprotection of photoreceptors for at least 2 months after retinal detachment.
Assuntos
Apoptose/efeitos dos fármacos , Dependovirus/genética , Terapia Genética , Células Fotorreceptoras de Vertebrados/patologia , Descolamento Retiniano/terapia , Proteínas Inibidoras de Apoptose Ligadas ao Cromossomo X/genética , Animais , Caspase 3/metabolismo , Caspase 9/metabolismo , Modelos Animais de Doenças , Vetores Genéticos , Proteínas de Fluorescência Verde/genética , Marcação In Situ das Extremidades Cortadas , Masculino , Fármacos Neuroprotetores , Células Fotorreceptoras de Vertebrados/enzimologia , Ratos , Ratos Endogâmicos BN , Descolamento Retiniano/enzimologia , TransfecçãoRESUMO
BACKGROUND: Retinitis pigmentosa (RP) is a blinding genetic disorder that is caused by the death of photoreceptors in the outer nuclear layer of the retina. To date, 39 different genetic loci have been associated with the disease, and 28 mutated genes have been identified. Despite the complexity of the underlying genetic basis for RP, the final common pathway is photoreceptor cell death via apoptosis. METHODOLOGY/PRINCIPAL FINDINGS: In this study, P23H and S334ter rhodopsin transgenic rat models of RP were used to test the neuroprotective effects of anti-apoptotic gene therapy. Adeno-associated viruses (AAV) carrying the X-linked inhibitor of apoptosis (XIAP) or green fluorescent protein (GFP) were delivered subretinally into the eye of transgenic rat pups. Histological and functional measures were used to assess neuroprotection. XIAP is known to block apoptosis by inhibiting the action of caspases-3, -7 and -9. The results show that XIAP gene therapy provides long-term neuroprotection of photoreceptors at both structural and functional levels. CONCLUSIONS/SIGNIFICANCE: Our gene therapy strategy targets the apoptotic cascade, which is the final common pathway in all forms of retinitis pigmentosa. This strategy holds great promise for the treatment of RP, as it allows for the broad protection of photoreceptors, regardless of the initial disease causing mutation.