Options for tracking GFP-Labeled transplanted myoblasts using in vivofluorescence imaging: implications for tracking stem cell fate

Abstract

BackgroundGreen fluorescent protein (GFP) is a useful biomarker, widely used in biomedical research to track stem cells after transplantation and/or to assess therapeutic transgene expression. However, both GFP and therapeutic gene products themselves may be immunogenic to the recipient. The main aim of this study was to use animal models to evaluate potential impact of GFP on the cell engraftment and to optimize tracking strategies prior to transplantation.ResultsBy using a fluorescent imaging (FLI) system, we investigated the dynamic cell behavior of GFP-transduced myoblasts in tibialis anterior (TA) muscles of immunocompetent mdx mice and immuno-compromised nude mice over a period of three months. The results suggested an apparent underlying host immunorejection in the mdx mice. Dystrophin immunostaining showed that the engraftment of wild type myoblasts was much more effective than that of the GFP-labeled counterparts in the mdx mice, further confirming an antigen role of GFP in this process. We tracked the GFP-transduced myoblasts in C57BL/6 mice and found GFP to be minimally immunogenic in these animals, as indicated by the GFP signal maintaining a much stronger level than that found in mdx and BALB/c mice at parallel time points. We also compared the in vivo cell behavior differences between myoblasts from virally GFP-transduced and GFP transgenic mice. The latter displayed much better engraftment, as determined both biomaging and histological observations.ConclusionsOur results not only demonstrated the immunogenicity of GFP in immunocompetent mice, but determined the optimized conditions for GFP-based in vivo stem cells tracking, that can potentially be extrapolated to human biomedical research.

A transgenic-cloned pig model expressing non-fluorescent modified Plum

“…For example, when transgenic (Tg) rat skin [18] or limbus [19] expressing GFP was transplanted into syngenic inbred rats, the antigenicity of the fluorescent proteins was thought to be the cause of the reported tissue rejection. Similar rejection was reported when GFP-expressing lymphocytes [20] and myoblasts [21] were transplanted into syngenic inbred mice. Based on these examples, exogenous fluorescent proteins and their genetic derivatives are thought to have antigenicity in mammals [22,23,24].…”

Differentiation of Apical Bud Cells in a Newly Developed Apical Bud Transplantation Model Using GFP Transgenic Mice as Donor

“…The green fluorescent mandibular incisors were obtained from transgenic mice. Without any preceding treatment, the green fluorescent cells from donor mice were proven to be utilized for tracing after transplantation [ 8 , 18 – 20 , 24 , 25 ]. The green fluorescence was directly detected by exposing specimens to 488 nm laser light.…”

Study of the involvement of allogeneic MSCs in bone formation using the model of transgenic mice

“…It has been found that GFP itself may be immunogenic in immunocompetent mice. 38 Thus the fact of a greater bone production by GFP(¡) MSCs comparing to GPF(C)MSCs may be directly related to the immunogenic properties of GFP and its impact on the cell behavior and viability.…”