Diabetes can impair wound closure, which can give rise to major clinical problems. Most treatments for wound repair in diabetes remain ineffective. This study aimed to investigate the influence on wound closure of treatments using expanded human cord blood CD34 + cells (CB-CD34 + cells), freshly isolated CB-CD34 + cells and a cytokine cocktail. The test subjects were mice with streptozotocin-induced diabetes. Wounds treated with fresh CB-CD34 + cells showed more rapid repair than mice given the PBS control. Injection of expanded CB-CD34 + cells improved wound closure significantly, whereas the injection of the cytokine cocktail alone did not improve wound repair. The results also demonstrated a significant decrease in epithelial gaps and advanced re-epithelialization over the wound bed area after treatment with either expanded CB-CD34 + cells or freshly isolated cells compared with the control. In addition, treatments with both CB-CD34 + cells and the cytokine cocktail were shown to promote recruitment of CD31 + -endothelial cells in the wounds. Both the CB-CD34 + cell population and the cytokine treatments also enhanced the recruitment of CD68-positive cells in the early stages (day 3) of treatment compared with PBS control, although the degree of this enhancement was found to decline in the later stages (day 9). These results demonstrated that expanded CB-CD34 + cells or freshly isolated CB-CD34 + cells could accelerate wound repair by increasing the recruitment of macrophages and capillaries and the reepithelialization over the wound bed area. Our data suggest an effective role in wound closure for both ex vivo expanded CB-CD34 + cells and freshly isolated cells, and these may serve as therapeutic options for wound treatment for diabetic patients. Wound closure acceleration by expanded CB-CD34 + cells also breaks the insufficient quantity obstacle of stem cells per unit of cord blood and other stem cell sources, which indicates a broader potential for autologous transplantation.

Wilms’ tumor 1 (WT1) is a transcription factor which plays a major role in cell proliferation, differentiation, survival, and apoptosis. WT1 was first identified as a tumor suppressor gene in Wilms’ tumor. However, overexpression of WT1 has been detected in several types of malignancy including some types of leukemia. To investigate the molecular mechanism underlying WT1-mediated leukemogenesis, lentiviral-based siRNA was employed as a tool to suppress WT1 expression in the myeloid leukemia cell line, K562. Successfully, both WT1 RNA and protein levels were downregulated in the leukemia cells. The silencing of WT1 resulted in significant growth inhibition in WT1-siRNA-treated cells for 40 ± 7.0 % , 44 ± 9.5 % , and 88 ± 9.1 % at 48, 72, and 96 hours posttransduction as compared with the control cells, respectively. By using apoptosis detection assays (caspase-3/7 activity and Annexin V-FITC/PI assays), WT1 silencing induced a higher degree of early and late apoptosis in siRNA-treated K562 as compared with the control cells. Interestingly, the expression of survival signaling genes, IL-2, IL-2RB, and IL-2RG, was also suppressed after WT1-siRNA treatment. In addition, the WT1 silencing also inhibited the S phase of the cell cycle and induced cell death. Our results indicated that WT1 silencing by siRNA can suppress cellular proliferation, induce apoptosis, and reduce S phase fraction of K562 cells. Moreover, transcriptional modulation of IL-2, IL-2RB, and IL2-2RG expression by WT1 was likely involved in this phenotypic change. Overall, this study confirmed the oncogenic role of WT1 in myeloid leukemia and discovered the new target genes of WT1 which are likely involved in WT1-mediated leukemogenesis.