Effect of in vivo culture condition on the proliferation and differentiation of rat adipose-derived stromal cells
Adipose-derived stromal cells (ADSCs) represent a promising stem cell source for tissue engineering and cell based therapy. However, long-term in vitro expansion of ADSCs impede stemness maintaining, partly attributed to deprivation of their original microenvironment. Incompetent cells largely limit the therapeutic effects in ADSCs based clinical use. Therefore, reconstructing a more physiologically and physically relevant niche is an ideal strategy to settle this issue and therefore facilitates their extensive applications in clinical. Here, we transplanted separated ADSCs to local subcutaneous adipose tissues of nude mice as an in vivo cell culture model. We found transplanted ADSCs maintained the primitive morphologies, showed improved proliferation and delayed senescence when compared to cells in conventional incubator. Significantly increased expression of stemness-related markers and multi-lineage differentiation abilities were further observed in in vivo cultured ADSCs. At last, sequencing results revealed different expression genes between ADSCs obtained from in vivo and in vitro conditions mainly located in extracellular matrix and extracellular space, which participated in regulating transcription and protein synthesis. Moreover, we found an Egr1 involved signaling pathway might exert a crucial impact on controlling stemness properties. Our findings might collectively pave the way between the bench and beside in regard of ADSCs based application. Overall design: To evaluate the effect of in vivo culture condition on the stemness property of ADSCs, we cultured rat primary ADSCs in two different conditions, and ADSCs were divided in three groups in our study: Con-ADSCs: the 4th passage ADSCs isolated from GFP transgenic rat adipose tissue. Vitro-ADSCs: the 4th passage ADSCs traditionally cultured and passaged in a incubator, and collected at the same time point of the Vivo-ADSCs group. Vivo-ADSCs: the 4th passage ADSCs injected into adipose tissues of nude mice and re-isolated after 7 day of injection. Subsequently,  we performed gene expression profiling analysis using data obtained from RNA-seq of  cells from the above three groups. Comparative gene expression profiling analysis of RNA-seq data for Con-ADSCs, Vitro-ADSCs and Vivo-ADSCs.