RESUMEN
This study explores the general utility of a new class of biosensor that allows one to selectively visualize molecules of a chosen membrane protein that are at the cell surface. These biosensors make use of recently described bipartite fluoromodules comprised of a fluorogen-activating protein (FAP) and a small molecule (fluorogen) whose fluorescence increases dramatically when noncovalently bound by the FAP (Szent-Gyorgyi et al., Nat Biotechnol 2010;00:000-000).
Asunto(s)
Técnicas Biosensibles/métodos , Colorantes Fluorescentes/metabolismo , Proteínas de la Membrana/metabolismo , Agonistas de Receptores Adrenérgicos beta 2 , Animales , Membrana Celular/metabolismo , Supervivencia Celular , Regulador de Conductancia de Transmembrana de Fibrosis Quística/metabolismo , Endocitosis , Colorantes Fluorescentes/química , Transportador de Glucosa de Tipo 4/metabolismo , Humanos , Proteínas de la Membrana/química , Ratones , Microscopía Fluorescente , Células 3T3 NIH , Estructura Terciaria de Proteína , Receptores Adrenérgicos beta 2/metabolismoRESUMEN
Genetic engineering of mesenchymal stem cells (MSCs) and neuronal stem cells (NSCs) has been used to treat spinal cord injuries (SCI). As a mechanism of therapy, MSCs secrete high amounts of trophic factors, while NSCs can differentiate into neuronal lineages and aid in tissue replacement. Additionally, the forced overexpression of secreted proteins can enhance the secretome of transplanted cells, which can increase therapeutic efficacy. This study utilized a combinational treatment consisting of MSCs, NSCs, and the forced overexpression of the chemokine stromal-derived factor-1 (SDF-1) from MSCs (SDF-1-MSCs) as treatment in a rat model of SCI. Transplants occurred at 9-days post-injury, and motor functions were evaluated for 7-weeks post-injury. White matter sparing and axon densities surrounding the lesions were quantified. Findings from this study demonstrate that co-transplanting SDF-1-MSCs with NSCs improved motor functions and enhanced axon densities surrounding the lesion. However, no improvements in white matter sparing were found and tumors were found in some of the animals that received co-transplantations with either SDF-1-MSCs and NSCs or unmodified-MSCs and NSCs, but not in any animal treated with a single cell type. This study offers evidence that providing SDF-1 to NSCs, through the forced expression from MSCs, can enhance the therapeutic potential of the graft, but developing a safe means of doing this requires further work.