RESUMEN
Reporter gene-based magnetic resonance imaging (MRI) offers unique insights into behavior of cells after transplantation, which could significantly benefit stem cell research and translation. Several candidate MRI reporter genes, including one that encodes for iron storage protein ferritin, have been reported, and their potential applications in embryonic stem (ES) cell research have yet to be explored. We have established transgenic mouse ES (mES) cell lines carrying human ferritin heavy chain (FTH) as a reporter gene and succeeded in monitoring the cell grafts in vivo using T(2)-weighted MRI sequences. FTH generated MRI contrast through compensatory upregulation of transferrin receptor (Tfrc) that led to increased cellular iron stored in ferritin-bound form. At a level sufficient for MRI contrast, expression of FTH posed no toxicity to mES cells and did not interfere with stem cell pluripotency as observed in neural differentiation and teratoma formation. The compatibility and functionality of ferritin as a reporter in mES cells opens up the possibility of using MRI for longitudinal noninvasive monitoring of ES cell-derived cell grafts at both molecular and cellular levels.
Asunto(s)
Células Madre Embrionarias/citología , Genes Reporteros/genética , Imagen por Resonancia Magnética/métodos , Transgenes/genética , Animales , Línea Celular , Células Madre Embrionarias/metabolismo , Proteínas Fluorescentes Verdes/metabolismo , Humanos , Ratones , Neoplasias/patología , Células Madre Pluripotentes/citología , Células Madre Pluripotentes/metabolismo , Cambios Post MortemRESUMEN
Non-human primates are valuable for modelling human disorders and for developing therapeutic strategies; however, little work has been reported in establishing transgenic non-human primate models of human diseases. Huntington's disease (HD) is an autosomal dominant neurodegenerative disorder characterized by motor impairment, cognitive deterioration and psychiatric disturbances followed by death within 10-15 years of the onset of the symptoms. HD is caused by the expansion of cytosine-adenine-guanine (CAG, translated into glutamine) trinucleotide repeats in the first exon of the human huntingtin (HTT) gene. Mutant HTT with expanded polyglutamine (polyQ) is widely expressed in the brain and peripheral tissues, but causes selective neurodegeneration that is most prominent in the striatum and cortex of the brain. Although rodent models of HD have been developed, these models do not satisfactorily parallel the brain changes and behavioural features observed in HD patients. Because of the close physiological, neurological and genetic similarities between humans and higher primates, monkeys can serve as very useful models for understanding human physiology and diseases. Here we report our progress in developing a transgenic model of HD in a rhesus macaque that expresses polyglutamine-expanded HTT. Hallmark features of HD, including nuclear inclusions and neuropil aggregates, were observed in the brains of the HD transgenic monkeys. Additionally, the transgenic monkeys showed important clinical features of HD, including dystonia and chorea. A transgenic HD monkey model may open the way to understanding the underlying biology of HD better, and to the development of potential therapies. Moreover, our data suggest that it will be feasible to generate valuable non-human primate models of HD and possibly other human genetic diseases.
