Use of Ferritin Expression, Regulated by Neural Cell-Specific Promoters in Human Adipose Tissue-Derived Mesenchymal Stem Cells, to Monitor Differentiation with Magnetic Resonance Imaging In Vitro.

Chengang Song,Xiaogang Jiang,Xiaoyun Li,Shuhua Mu,Shizhen Zhong,Jiachuan Wang,Zhenfu Zhao,Guangqian Zhou,Cuiping Mo,Heye Zhang

doi:10.1371/journal.pone.0132480

Abstract

The purpose of this study was to establish a method for monitoring the neural differentiation of stem cells using ferritin transgene expression, under the control of a neural-differentiation-inducible promoter, and magnetic resonance imaging (MRI). Human adipose tissue-derived mesenchymal stem cells (hADMSCs) were transduced with a lentivirus containing the human ferritin heavy chain 1 (FTH1) gene coupled to one of three neural cell-specific promoters: human synapsin 1 promoter (SYN1p, for neurons), human glial fibrillary acidic protein promoter (GFAPp, for astrocytes), and human myelin basic protein promoter (MBPp, for oligodendrocytes). Three groups of neural-differentiation-inducible ferritin-expressing (NDIFE) hADMSCs were established: SYN1p-FTH1, GFAPp-FTH1, and MBPp-FTH1. The proliferation rate of the NDIFE hADMSCs was evaluated using a Cell Counting Kit-8 assay. Ferritin expression was assessed with western blotting and immunofluorescent staining before and after the induction of differentiation in NDIFE hADMSCs. The intracellular iron content was measured with Prussian blue iron staining and inductively coupled plasma mass spectrometry. R2 relaxation rates were measured with MRI in vitro. The proliferation rates of control and NDIFE hADMSCs did not differ significantly (P > 0.05). SYN1p-FTH1, GFAPp-FTH1, and MBPp-FTH1 hADMSCs expressed specific markers of neurons, astrocytes, and oligodendrocytes, respectively, after neural differentiation. Neural differentiation increased ferritin expression twofold, the intracellular iron content threefold, and the R2 relaxation rate two- to threefold in NDIFE hADMSCs, resulting in notable hypointensity in T2-weighted images (P < 0.05). These results were cross-validated. Thus, a link between neural differentiation and MRI signals (R2 relaxation rate) was established in hADMSCs. The use of MRI and neural-differentiation-inducible ferritin expression is a viable method for monitoring the neural differentiation of hADMSCs.

Highlights

Most neurological disorders are caused by the loss of neurons or glial cells in the brain or spinal cord
The results suggested that ferritin overexpression did not inhibit Human adipose tissuederived mesenchymal stem cells (hADMSCs) proliferation
In neural-differentiation-inducible ferritinexpressing (NDIFE) hADMSCs, the expression of neural cell-specific markers changed after neural differentiation (Fig 3)

Summary

Introduction

Most neurological disorders are caused by the loss of neurons or glial cells in the brain or spinal cord. Current therapies for these disorders are unable to replace damaged or lost neural cells. Cell-based therapy offers the possibility of enhancing tissue repair and functional recovery in neurological disorders. MSCs have been used in several regenerative methods in animal models or patients with neurological diseases [1,2,3,4] and have been shown to enhance neurological recovery. A noninvasive, real-time, sensitive, and clinically applicable method for tracking transplanted MSCs and monitoring their behavior in live animals would be useful

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