Effect of in vivo culture conditions on the proliferation and differentiation of rat adipose-derived stromal cells

Adipose-derived stromal cells (ADSCs) are a promising stem cell sources for tissue engineering and cell-based therapy. However, long-term in vitro expansion of ADSCs impedes stemness maintenance, which is partly attributed to deprivation of their original microenvironment. Incompetent cells limit the therapeutic effects of ADSC-based clinical strategies. Therefore, reconstructing a more physiologically and physically relevant niche is an ideal strategy to address this issue and therefore facilitates the extensive application of ADSCs. Here, we transplanted separated ADSCs into local subcutaneous adipose tissues of nude mice as an in vivo cell culture model. We found that transplanted ADSCs maintained their primitive morphology and showed improved proliferation and delayed senescence compared to those of cells cultured in a incubator. Significantly increased expression of stemness-related markers and multilineage differentiation abilities were further observed in in vivo cultured ADSCs. Finally, sequencing revealed that genes whose expression differed between ADSCs obtained under in vivo and in vitro conditions were mainly located in the extracellular matrix and extracellular space and that these genes participate in regulating transcription and protein synthesis. Moreover, we found that an Egr1 signaling pathway might exert a crucial impact on controlling stemness properties. Our findings might collectively pave the way for ADSC-based applications.

NR4A3 induces endothelial dysfunction through up-regulation of endothelial 1 expression in adipose tissue-derived stromal cells

Hypertension is one of the most prevalent diseases worldwide. Increased synthesis of the vasoconstrictor peptide endothelin 1 (encoded by EDN1) might be responsible for high blood pressure. The present study further confirmed the abnormal EDN1 upregulation within adipose tissue-derived stromal cells (ADSCs) derived from morbidly obese subjects. The overexpression of EDN1 in ADSCs derived from non-obese subjects significantly promoted the proliferation and migration of HUVECs and tube formation by human umbilical vein endothelial cell (HUVEC). Transcription factor NR4A3 was positively correlated with EDN1, binding to EDN1 promoter region to upregulate EDN1 expression. Similarly, the overexpression of NR4A3 in ADSCs derived from non-obese subjects significantly promoted the proliferation and migration of HUVECs and tube formation by HUVECs, as well as EDN1 protein levels in ADSCs. However, the effects of NR4A3 overexpression on EDN1 protein levels in ADSCs and the proliferation and migration of HUVECs and tube formation by HUVECs were significantly reversed by EDN1 silencing in ADSCs. In conclusion, NR4A3 is abnormally upregulated in ADSCs derived from morbidly obese subjects; NR4A3 could promote HUVEC angiogenesis through binding to EDN1 promoter and upregulating EDN1 expression.