IGF-1-Expressing Placenta-Derived Mesenchymal Stem Cells Promote Scalding Wound Healing.

BACKGROUND: Stem cell-based regenerative therapy is a novel approach to severe damaged skin. Perinatal tissues such as placenta are considered as promising alternatives. The present study aimed to investigate the effect of insulin-like growth factor-1 (IGF-1)-expressing placenta-derived mesenchymal stem cells (hPMSCs) on healing of burn wounds. MATERIALS AND METHODS: hPMSCs were isolated from human placenta, and IGF-1 was transducted into hPMSCs via lentivirus. Flow cytometry and MTT assay were performed to assess cell apoptosis and viability, respectively. Immunostaining of CK19 and ki67 was for evaluating epithelial differentiation ability and cell proliferation. For in vivo studies, we established a mouse model of scalding and performed local administration of IGF-1-expressing hPMSCs via subcutaneous injection. Wound histology was analyzed with H&E staining. The expression of fibrogenic cytokines was detected by western blot. The production of pro-inflammatory factors was measured by ELISA. RESULTS: Overexpression of IGF-1 promoted cell proliferation and epithelial differentiation of hPMSCs in vitro and in vivo. Mice with burn injury displayed increased wound contraction and healing rates following treatment with IGF-1-expressing hPMSCs. There was less inflammatory infiltration and reduced collagen disposition in the presence of IGF-1 at the wound site. Administration of IGF-1-expressing hPMSCs suppressed inflammation by decreasing the levels of pro-inflammatory cytokines including tumor necrosis factor-α, interleukin-1ß, and interleukin-6. Besides, IGF-1 increased VEGF expression, and decreased TGF-ß1, collagen I and collagen III expressions in vivo. CONCLUSIONS: IGF-1-expressing PMSCs promotes cell proliferation and epithelial differentiation, inhibits inflammation and collagen deposition, and thus contributes to wound healing.

MiR-133a-3p inhibits scar formation in scalded mice and suppresses the proliferation and migration of scar derived-fibroblasts by targeting connective tissue growth factor.

Excessive scar formation post burn injury can cause great pain to the patients. MiR-133a-3p has been demonstrated to be anti-fibrotic in some fibrosis-related diseases. However, its possible role in scar formation has not been elucidated yet. In present study, the effect of miR-133a-3p on scar formation was investigated in a scalded model of mice. Moreover, the function of miR-133a-3p on proliferation and migration of scar-derived fibroblasts (SFs) was studied in vitro. It was found that miR-133a-3p was dramatically downregulated in scar tissue of scalded mice. Upregulation of miR-133a-3p by miR-133a-3p agomir obviously inhibited the scar formation in scalded mice. Histological staining showed that upregulation of miR-133a-3p attenuated the excessive deposition of collagen in scar tissue of scalded mice. In vitro study showed that upregulation of miR-133a-3p effectively suppressed the proliferation and migration of SFs. Besides, upregulation of miR-133a-3p attenuated the protein levels of α-smooth muscle actin (α-SMA) and collagen I, indicating that miR-133a-3p could suppress the activation of SFs. The expression of connective tissue growth factor (CTGF), a critical mediator in cell proliferation, migration and extracellular matrix (ECM) synthesis, was also downregulated by the upregulation of miR-133a-3p. Luciferase reporter assay validated that CTGF was directly targeted by miR-133a-3p. In addition, overexpression of CTGF abolished the effect of miR-133a-3p on inhibiting the proliferation, migration and activation of SFs, indicating that miR-133a-3p functioned by targeting CTGF. Therefore, miR-133a-3p might be a promising target for treating pathological scars.

MiR-375-3p alleviates the severity of inflammation through targeting YAP1/LEKTI pathway in HaCaT cells.

Atopic dermatitis (AD) is a relapsing inflammatory skin disease with a complicated pathogenesis. This study aimed to investigate whether miR-375-3p could regulate AD through the Yes-associated protein 1 (YAP1) pathway. In this study, inflammatory response was induced by TNF-α and IFN-γ administration in HaCaT cells. We found that viability and inflammatory factor release, including interleukin-1ß (IL-1ß) and IL-6, were negatively related to miR-375-3p expression in HaCaT cells. We also found that YAP1 overexpression down-regulated lympho-epithelial Kazal type inhibitor (LEKTI) levels and aggravated viability and inflammation in TNF-α and IFN-γ-treated HaCaT cells. Dual-luciferase reporter assay proved the targeted binding of miR-375-3p and YAP1 3'-UTR. Additionally, the protective effect of miR-375-3p on inflammatory response in TNF-α and IFN-γ-treated HaCaT cells could be impeded by YAP1 overexpression. Collectively, our results suggested that miR-375-3p could modulate HaCaT cell viability and inflammation through the YAP1/LEKTI pathway.

Hypoxia enhances the protective effects of placenta-derived mesenchymal stem cells against scar formation through hypoxia-inducible factor-1α.

OBJECTIVES: To explore the effect of placenta-derived mesenchymal stem cells on scar formation as well as the underlying mechanism. RESULTS: The isolated placenta-derived mesenchymal stem cells from mice were distributed in the wounded areas of scalded mouse models, attenuated inflammatory responses and decreased the deposition of collagens, thus performing a beneficial effect against scar formation. Hypoxia enhanced the protective effect of placenta-derived mesenchymal stem cells and hypoxia-inducible factor-1α was involved in the protective effect of placenta-derived mesenchymal stem cells in hypoxic condition. CONCLUSIONS: Hypoxia enhanced the protective effect of placenta-derived mesenchymal stem cells through hypoxia-inducible factor-1α and PMSCs may have a potential application in the treatment of wound.

Hypoxic conditioned medium of placenta-derived mesenchymal stem cells protects against scar formation.

AIMS: Scar formation after wound repair affects people's daily life. Mesenchymal stem cells were reported to have a beneficial role in attenuating the scar formation. In the present study, placenta-derived mesenchymal stem cells (PMSCs) were isolated and the effects of hypoxic conditioned medium of PMSCs on scar formation were explored. MAIN METHODS: To evaluate the effect of hypoxia on PMSCs, proliferation of PMSCs was detected by trypan blue staining and the HIF-1α level was detected by western blot. Then in vivo scar formation assay was performed and the histopathologic changes were evaluated by HE staining and levels of TGF-ß1 and collagen I were detected by quantitative real-time PCR. The IL-10 level was detected by ELISA and then migration of HFF-1 cells was detected by wound healing assay after treatment with IL-10 or IL-10 antibody. KEY FINDINGS: Our study showed that hypoxic conditioned medium of PMSCs reduced scar formation in vivo and inhibited the proliferation and migration of skin fibroblasts in vitro. Further mechanism study showed that, the level of IL-10 was affected by hypoxia, treatment with IL-10 mimicked the function of hypoxic conditioned medium of PMSCs and inhibition of IL-10 reversed the protective role of hypoxic conditioned medium of PMSCs. Thus, hypoxic conditioned medium of PMSCs may perform the protective role against scar formation through IL-10. SIGNIFICANCE: Our study reveals a possible mechanism of the protective effect of PMSCs against scar formation and provides evidence for the hypothesis that PMSCs may be a promising therapy for the treatment of wounds.