During wound healing and tissue repair the dermal fibroblast-to-myofibroblast transdifferentiation plays an important role, transforming growth factor-β1 (TGF-β1) is considered to be the main stimuli factor of transdifferentiation. MicroRNAs (miRNAs) have recently emerged as key post-transcriptional regulators of gene expression. The involvement of miRNAs and their roles in TGF-β1-induced myofibroblast transdifferentiation remains to be determined in detail. The current study found that the expression of miR-146a was upregulated in human dermal fibroblasts cells in response to TGF-β1 stimulation in dose-dependent manner by quantitative RT-PCR. Bioinformatic analyses predict that signaling effectors mothers against decapentaplegic protein 4 (SMAD4) is a miR-146a target gene. Luciferase assay demonstrated that miR-146a mimics suppressed SMAD4 3'-UTR reporter construct activity. Furthermore, miR-146a overexpression in dermal fibroblast did not decrease target mRNA levels, but significantly reduced target protein expression. In addition, dermal fibroblasts transfected with miR-146a mimics exhibited attenuated TGF-β1 -induced α-smooth muscle actin (α-SMA) expression compared with the control. This study demonstrated that miR-146a may function as a novel negative regulator to modulate myofibroblast transdifferentiation during TGF-β1 induction by targeting SMAD4.

Abstract. HIV-1 derived lentiviral vectors (LVs) have emerged as a powerful tool for gene delivery. hTERT is an ideal tumorassociated antigen with which to develop a potential dendritic cell (DC) vaccine. The purpose of this study was to construct a recombinant lentivirus vector of the hTERT peptide and to determine the hTERT-specific cytotoxic T lymphocyte response elicited by DCs transfected with hTERT-lentivirus vectors in vitro. LVs encoding the hTERT peptide were constructed, DCs from cord blood were prepared, their morphology was observed and phenotype was analyzed by flow cytometry. Lenti-hTERT was transfected into DCs to construct the DC vaccines. T lymphocytes stimulated with DC vaccines and HepG2 cells (hTERT + ) or 293T cells (hTERT -) were co-cultured for 24 h, respectively. The ability to stimulate proliferation of allogeneic T lymphocytes and the killing activity of CTLs activated by these DCs were determined using the MTT method. According to our results, the recombinant vector lenti-hTERT and lenti-hTERT-DC vaccine were successfully constructed. The stimulatory capacity of the lenti-hTERT DCs in the allogeneic T lymphocyte reaction was markedly enhanced compared with the DC control group (P<0.01). Inhibition rates in HepG2 cells of CTLs stimulated with lenti-hTERT-DCs (CTL T ) were significantly higher than CTLs stimulated with the control DC group (CTL N ) (P<0.01). Inhibition rates in 293T cells of CTL T and CTL N were low and there was no difference between the different DC groups (P>0.05). DCs transfected with the hTERT peptide were capable of eliciting a stronger hTERT-specific CTL response in vitro. Our data indicate that lenti-hTERT-DCs may potentially be used as an effective approach for cancer immunotherapy.