RESUMO
Leber's hereditary optic neuropathy (LHON) is a visual impairment associated with mutations of mitochondrial genes encoding elements of the electron transport chain. While much is known about the genetics of LHON, the cellular pathophysiology leading to retinal ganglion cell degeneration and subsequent vision loss is poorly understood. The impacts of the G11778A mutation of LHON on bioenergetics, redox balance and cell proliferation were examined in patient-derived fibroblasts. Replacement of glucose with galactose in the culture media reveals a deficit in the proliferation of G11778A fibroblasts, imparts a reduction in ATP biosynthesis, and a reduction in capacity to accommodate exogenous oxidative stress. While steady-state ROS levels were unaffected by the LHON mutation, cell survival was diminished in response to exogenous H2O2.
Assuntos
DNA Mitocondrial , Fibroblastos , Galactose , Mutação , Atrofia Óptica Hereditária de Leber , Humanos , Fibroblastos/metabolismo , Fibroblastos/efeitos dos fármacos , Atrofia Óptica Hereditária de Leber/genética , Atrofia Óptica Hereditária de Leber/metabolismo , Atrofia Óptica Hereditária de Leber/patologia , DNA Mitocondrial/genética , DNA Mitocondrial/metabolismo , Galactose/metabolismo , Mutação/genética , Proliferação de Células/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Mitocôndrias/metabolismo , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/genética , Células Cultivadas , Glucose/metabolismo , Glucose/farmacologiaRESUMO
The numbers and strengths of synapses in the brain change throughout development, and even into adulthood, as synaptic inputs are added, eliminated, and refined in response to ongoing neural activity. A number of experimental techniques can assess these changes, including single-cell electrophysiological recording which offers measurements of synaptic inputs with high temporal resolution. Coupled with electrical stimulation, photoactivatable opsins, and caged compounds, to facilitate fine spatiotemporal control over release of neurotransmitters, electrophysiological recordings allow for precise dissection of presynaptic and postsynaptic mechanisms of action. Here, we discuss the strengths and pitfalls of various techniques commonly used to analyze synapses, including miniature excitatory/inhibitory (E/I) postsynaptic currents, evoked release, and optogenetic stimulation. Together, these techniques can provide multiple lines of convergent evidence to generate meaningful insight into the emergence of circuit connectivity and maturation. A full understanding of potential caveats and alternative explanations for findings is essential to avoid data misinterpretation.