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Background and Purpose: Sirtuin1 (SIRT1), the founding member of mammalian class III histone deacetylases, is reported to be a drug target involved in fibrotic diseases. However, whether it is an effective drug target in hypertrophic scar treatment is still not known.Experimental Approach: In the present study, we observed that SIRT1 localized to both the epidermis and the dermis of skin tissues by immunohistochemistry. After knock-down of SIRT1 by shRNA or up-regulating SIRT1 by resveratrol, the expression of α-SMA, Col1 and Col3 in fibroblasts were detected by western blots. A mouse excision wound healing model was used to observe the changes in collagen fibre associated with the different expression levels of SIRT1.Key Results: SIRT1 expression was inhibited in hypertrophic scar tissue. The down-regulation of SIRT1 resulted in an increased expression of α-SMA, Col1 and Col3 in hypertrophic scar-derived fibroblasts. In contrast, the up-regulation of SIRT1 not only inhibited the expression of α-SMA, Col1 and Col3 in hypertrophic scar-derived fibroblasts but also blocked the activation of TGFβ1-induced normal skin-derived fibroblasts. In the mouse model of wound healing, the deletion of SIRT1 resulted in denser collagen fibres and a more disordered structure, whereas resveratrol treatment led to a more organized and thinner collagen fibre, which was similar to that observed during normal wound healing.Conclusions and Implications: The results revealed that SIRT1 negatively regulates TGFβ1-induced fibroblast activation and inhibits excessive scar formation and is, therefore, a promising drug target for hypertrophic scar formation. [ABSTRACT FROM AUTHOR]

Background/Aims: With increased understanding of sepsis, mortality is decreasing. However, there is still a lack of effective therapeutic strategy. The inflammatory response of macrophages is critical during sepsis. Methods: Macrophages were stimulated with LPS. Western blotting and qRT-PCR were used to detect inflammatory responses. Then, the inhibitor of microRNA-138 was transfected and Western blotting, qRT-PCR, H&E staining and ELISA were used to verify the role of microRNA-138 in inflammation. Then target gene prediction databases were used to predict the potential target of microRNA-138. Both animal and cell models under LPS challenges were established to verify the regulation of SIRT1 and microRNA-138 during inflammation. Results: The present study showed that microRNA-138 was increased in macrophages stimulated with LPS. Additionally, the NF-κB and AKT pathways were both activated. The pre-treatment of microRNA-138 inhibitor decreased inflammatory factors, downregulated the NF-κB pathway, activated the AKT pathway and protected against organ damage in mice challenged with LPS. SIRT1 was demonstrated as a potential target of microRNA-138In macrophages stimulated with LPS, the inhibition effect of microRNA-138 inhibitor on inflammation was lost by SIRT1 siRNA pre-treatment. In the animal model, the protective effect of microRNA-138 antagomir disappeared in SIRT1 knockout mice. Conclusion: We demonstrated that miR-138 participated in the inflammatory process by inhibiting SIRT1 and activating the NF-κB pathway. [ABSTRACT FROM AUTHOR]

Background: As an important oncogenic miRNA, microRNA-21 (miR-21) is associated with various malignant diseases. However, the precise biological function of miR-21 and its molecular mechanism in hypertrophic scar fibroblast cells has not been fully elucidated. Methodology/Principal Findings: Quantitative Real-Time PCR (qRT-PCR) analysis revealed significant upregulation of miR-21 in hypertrophic scar fibroblast cells compared with that in normal skin fibroblast cells. The effects of miR-21 were then assessed in MTT and apoptosis assays through in vitro transfection with a miR-21 mimic or inhibitor. Next, PTEN (phosphatase and tensin homologue deleted on chromosome ten) was identified as a target gene of miR-21 in hypertrophic scar fibroblast cells. Furthermore, Western-blot and qRT-PCR analyses revealed that miR-21 increased the expression of human telomerase reverse transcriptase (hTERT) via the PTEN/PI3K/AKT pathway. Introduction of PTEN cDNA led to a remarkable depletion of hTERT and PI3K/AKT at the protein level as well as inhibition of miR-21-induced proliferation. In addition, Western-blot and qRT-PCR analyses confirmed that hTERT was the downstream target of PTEN. Finally, miR-21 and PTEN RNA expression levels in hypertrophic scar tissue samples were examined. Immunohistochemistry assays revealed an inverse correlation between PTEN and hTERT levels in high miR-21 RNA expressing-hypertrophic scar tissues. Conclusions/Significance: These data indicate that miR-21 regulates hTERT expression via the PTEN/PI3K/AKT signaling pathway by directly targeting PTEN, therefore controlling hypertrophic scar fibroblast cell growth. MiR-21 may be a potential novel molecular target for the treatment of hypertrophic scarring. [ABSTRACT FROM AUTHOR]

Scarring, tightly associated with fibrosis, is a significant symptomatic clinical problem. Interleukin 10 (IL-10) has been identified as a candidate scar-improving therapy based on preclinical studies. However, the molecular mechanism of IL-10 in scar improvement is still uncertain. In this study, human dermal fibroblasts stimulated with TGF-β1 were treated with IL-10 to analyze the mRNA and some of proteins' expression levels of type I collagen (Col1), type III collagen (Col3), alpha-smooth muscle actin (α-SMA), matrix metalloproteinase-1 (MMP1), MMP2, MMP8 and tissue inhibitor of metalloproteinase 1 (TIMP1), TIMP2 by real-time PCR and Western blot, to observe α-SMA-positive fibroblasts by immunocytochemistry. The contracture and improvement of fibroblast-populated collagen lattice (FPCL) and a murine model of wound healing were used to evaluate the scar-improving effects by histological staining. The results showed that IL-10 can significantly down-regulate the mRNA and protein expression levels of Col1, Col3, α-SMA, and up-regulate the mRNA expression levels of MMP1 and MMP8, and decrease α-SMA-positive fibroblasts. FPCL analysis showed that the IL-10 (20 ng/ml) can significantly inhibit the contracture, improve the architecture of FPCL. Wounds injected with IL-10 demonstrated that the appearance of scar was improved, the wound margin of scarring was narrow, and the deposition of collagens (Col1 and Col3) in regenerated tissue was relieved. These results provide direct evidences that IL-10 has the inhibitory effects on the excessive deposition of extracellular matrix components and fibroblast-to-myofibroblast transition, and show that IL-10 has the potential therapy in prevention and reduction of skin scarring. [ABSTRACT FROM AUTHOR]

Autophagy is a tightly regulated physiological process essential for cellular maintenance, differentiation, development, and homeostasis. Aberration of this process associates with the pathogeneses of several diseases in mammals. Hypertrophic scar (HS) is characterized by an abundance of collagenous tissue with hypercellularity. However, the molecular mechanism in HS formation is poorly understood. We compared the autophagic capacity in HS and its normal skin (NS) counterparts and explored the molecular mechanism of autophagy during the formation of HS. Microtubule-associated protein 1 light chain 3 (LC3) proteins in HS and NS were detected by immunohistochemistry, Western blot and quantitative real-time PCR (qPCR). The data showed that LC3 positive staining in HS was less intensive relative to NS group ( p < 0.05). Three forms of LC3, with molecular weights of about 19 kDa (proLC3), 18 kDa (LC3-I) and 16 kDa (LC3-II), respectively, expressed in NS by Western blot. In contrast, only proLC3 expressed while both LC3-I and LC3-II were significantly downregulated in HS. The protein level of beclin 1 in HS was significantly lower compared with NS ( p < 0.05). LC3 and beclin 1 mRNA levels in HS were significantly lower than that in NS ( p < 0.05). These results suggest that the generation of LC3-I and LC3-II are interrupted in HS, and that the resultant decrease of autophagic capacity may associate with the pathogenesis of HS. [ABSTRACT FROM AUTHOR]