The impact of the bone marrow-derived mesenchymal stem cell on the microenvironment of the human limbal stem cell

Abstract

Background When limbal stem cell deficiency (LSCD) occurs,not only the limbal stem cells (LSCs) were damaged,but also the LSCs matrix microenvironment was under destruction.The treatment of LSCD include both replenishing of stem cells and restoration of microenvironment.So far,the method to improve the microenvironment of LSCD still exist limitation and urgently need to establish more appropriate microenvironment for the LSCs growth in vitro.Objective This study was to investigate whether the human bone marrow-derived mesenchymal stem cells (BMSCs) can be used as the ideal cells to repair limbal microenvironment and its possible mechanism of repairing limbal microenvironment during the human LSCs amplification in vitro as feeder cells.Methods BMSCs were cultured and passaged in vitro,and flow cytometry was used to assay the expressions of CD45,CD71,CD90,CD105 and HLA-DR and directionally induced BMSCs to the osteoblasts and adipocytes.BMSCs were treated using mitomycin C (MMC) to use as the feeder cells.LSCs were separately co-cultured with BMSCs,Swiss-3T3 feeder cells and free-feeder cells,and colony-forming efficiency (CFE) of the LSCs was compared among different co-cultured groups.LSCs were then cultured sequentially and identified by flow cytometry.Expression of cytokines in BMSCs was confirmed by reverse transcriptional polymerase chain reaction (RT-PCR).Results Cultured BMSCs showed a good homogeneity,with a lot of expressions of interstitial cell markers such as CD71,CD90,CD105 and less expressions of hematopoietic cell markers including CD45 and HLA-DR.After separately cocultured with feeder cells for 12 days,the CFE of the LSCs co-cultured with BMSCs,Swiss-3T3 and no feeder cells was 3.67％ ±0.58％,4.30％ ± 1.54％ and 0.20％ ±0.10％,showing a statistical significant difference among the three groups(F =15.420,P =0.040).There was no statistically significant difference in the C FE of the LSCs between the BMSCs feeder group and the Swiss-3T3 feeder cells group(P =0.456),between the BMSCs feeder group and the free-feeder cells group or the Swiss-3T3 co-culture group and the free-feeder cells group (P =0.005,0.002).LSCs presented with a positive response for ABCG2 antigen in the co-cultured with BMSCs group.Basic fibroblast growth factor(bFGF),stem cell factor (SCF) and N-cadherin(N-cad) were positively expressed in the BMSCs as feeder cells.Conclusions Human BMSCs-derived feeder cells can improve the growth of the stromal microenvironment of the LSCs and enhance their proliferation ability.Human BMSCs are suitable for engineering of epithelial sheets. Key words: Bone marrow-derived mesenchymal stem cell; Limbal stem cell; Feeder cell; Cell culture in vitro