Background : The retention rate in autologous fat grafting is an increasing concern for surgeons and patients. Our previous research verified that thymosin beta 4 (T¥â4) positively affected fat survival, while the mechanism was unknown. The endothelial cells (ECs) and exosomes derived from adipose-derived stem cells (ADSCs) were regarded to play a critical role in fat transplantation.
Objective : This study aimed to evaluate the effect of exosomes derived from T¥â4-treated ADSCs on EC proliferation and to identify the exosomal microRNA (miRNA) profile compared with the T¥â4-untreated group. Additionally, this research intended to recognize the related molecules and signaling pathways in the T¥â4-treated group with potential roles in fat transplants.
Methods : ADSCs were collected from patients who underwent liposuction surgery. Depending on whether the medium was supplemented with exogenous T¥â4 or not, exosomes derived from cultured ADSCs were divided into the T¥â4-Exos group and Con-Exos group. Exosome uptake and cell counting kit-8 (CCK-8) assays assessed the influence of T¥â4-Exos on EC proliferation. The exosomal miRNAs of the two groups were analyzed by next-generation sequencing. With the criteria at the |log2 (fold change)|?¡Ã?1 and p-value?0.05, up-regulated and down-regulated differentially expressed miRNAs (DEMs) were obtained. Prediction databases were used to predict the downstream mRNAs for DEMs. And then, overlapping genes for the up-regulated DEMs and the down-regulated were screened out, followed by enrichment analysis, protein?protein interaction network construction, and the gene cluster and hub gene identification.
Results : ADSCs were obtained from four female patients. The exosome uptake and CCK-8 assays showed that the T¥â4-Exos could increase cell growth rate compared with the control group (DMEM-H?+?PBS). In T¥â4-Exos and Con-Exos groups, 2651 exosomal miRNAs were recognized, with 80 up-regulated and 99 down-regulated DEMs according to the criteria. After the prediction, 621 overlapping genes for the up-regulated and 572 for the down-regulated DEMs were screened. The subsequent bioinformatics analysis found specific molecules and pathways related to the positive effect on fat survival.
Conclusions : The exosomes derived from T¥â4-treated ADSCs probably positively affect EC proliferation. Compared with the Con-Exos group, several exosomal DEMs, genes, and pathways were distinguished. These findings of this exploratory study provide the potential direction for future in-depth research on fat grafting.
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