Bone Marrow Mesenchymal Stem Cells Stimulate Proliferation and Neuronal Differentiation of Retinal Progenitor Cells

Jing Ji,Pranela Rameshwar,Ni Ni,Min Luo,Yamin Hu,Junzhao Chen,Yuan Deng,Jibo Zhou,Ping Gu,Xianqun Fan,Jing Xia

doi:10.1371/journal.pone.0076157

Abstract

During retina development, retinal progenitor cell (RPC) proliferation and differentiation are regulated by complex inter- and intracellular interactions. Bone marrow mesenchymal stem cells (BMSCs) are reported to express a variety of cytokines and neurotrophic factors, which have powerful trophic and protective functions for neural tissue-derived cells. Here, we show that the expanded RPC cultures treated with BMSC-derived conditioned medium (CM) which was substantially enriched for bFGF and CNTF, expressed clearly increased levels of nuclear receptor TLX, an essential regulator of neural stem cell (NSC) self-renewal, as well as betacellulin (BTC), an EGF-like protein described as supporting NSC expansion. The BMSC CM- or bFGF-treated RPCs also displayed an obviously enhanced proliferation capability, while BMSC CM-derived bFGF knocked down by anti-bFGF, the effect of BMSC CM on enhancing RPC proliferation was partly reversed. Under differentiation conditions, treatment with BMSC CM or CNTF markedly favoured RPC differentiation towards retinal neurons, including Brn3a-positive retinal ganglion cells (RGCs) and rhodopsin-positive photoreceptors, and clearly diminished retinal glial cell differentiation. These findings demonstrate that BMSCs supported RPC proliferation and neuronal differentiation which may be partly mediated by BMSC CM-derived bFGF and CNTF, reveal potential limitations of RPC culture systems, and suggest a means for optimizing RPC cell fate determination in vitro.

Highlights

Visual impairment, including retinitis pigmentosa, age-related macular degeneration, glaucoma and diabetic retinopathy, severely affects the quality of life of patients and their families
The retinal progenitor cell (RPC) were cultured in Bone marrow mesenchymal stem cells (BMSCs), lens and neural stem cell (NSC) conditioned medium (CM), and morphology images were taken on days 1, 4 and 7 (Figure 1)
In response to NSC CM (Figure 1C, G, K) or standard culture medium (SM) (Figure 1D, H, L), most RPCs grew as spherical clusters that adhered to the uncoated flask or floated in the culture medium

Summary

Introduction

Visual impairment, including retinitis pigmentosa, age-related macular degeneration, glaucoma and diabetic retinopathy, severely affects the quality of life of patients and their families. Retinal progenitor cells (RPCs) are a subset of undifferentiated cells that have the ability to self-renew and the potential to differentiate into various retinal neurons [3] They are capable of cytoarchitectural integration and differentiation towards cells expressing characteristic markers of retinal neurons, thereby improving visual function in the host [3,4]. These findings suggest that RPCs may be able to replace degenerating retinal cells. These studies described promising therapeutic applications of RPCs, there are numerous related issues and concerns, including the improvement of proliferation capacity and the preferential differentiation into specific neurons but not glial cells. Among the most accessible strategies is an attractive strategy of co-culture that has been considered to improve the proliferation and differentiation of progenitor cells [5,6,7]

Results

Discussion

Conclusion