Julei Zhang

MicroRNA-192 regulates hypertrophic scar fibrosis by targeting SIP1

Hypertrophic scar (HS) is a fibro-proliferative disorder which is characterized by excessive deposition of collagen and accumulative activity of myofibroblasts. Increasing evidences have demonstrated miRNAs play a pivotal role in the pathogenesis of HS. MiR-192 is closely associated with renal fibrosis, but its effect on HS formation and skin fibrosis remains unknown. In the study, we presented that miR-192 was up-regulated in HS and HS derived fibroblasts (HSFs) compared to normal skin (NS) and NS derived fibroblasts (NSFs), accompanied by the reduction of smad interacting protein 1 (SIP1) expression and the increase of Col1, Col3 and α-SMA levels. Furthermore, we confirmed SIP1 was a direct target of miR-192 by using luciferase reporter assays. Meanwhile, the overexpression of miR-192 increased the levels of Col1, Col3 and α-SMA. The synthesis of collagen and more positive α-SMA staining were also observed in bleomycin-induced dermal fibrosis model of BALB/c mice treated with subcutaneous miR-192 mimics injection, whereas the inhibition of miR-192 decreased the expression of Col1, Col3 and α-SMA. Moreover, SIP1 siRNA could enhance the levels of Col1, Col3 and α-SMA, showing that the effect of knockdown SIP1 was similar to miR-192 mimics, and the phenomenon manifested miR-192 regulated HS fibrosis by targeting SIP1. Together, our results indicated that miR-192 was a critical factor of HS formation and facilitated skin fibrosis by targeting directly SIP1.

Acute down-regulation of miR-199a attenuates sepsis-induced acute lung injury by targeting SIRT1

MicroRNA-199a (miR-199a) is a novel gene regulator with an important role in inflammation and lung injury. However, its role in the pathogenesis of sepsis-induced acute respiratory distress syndrome (ARDS) is currently unknown. Our study explored the role of miR-199a in sepsis-induced ARDS and its mechanism of action. First, we found that LPS could upregulate miR-199a in alveolar macrophages. Downregulation of miR-199a inhibited the upregulation of inflammatory cytokines in alveolar macrophages and induced the remission of histopathologic changes, the reduction of proinflammatory cytokines, and the upregulation of apoptosis protein expression in an ARDS lung, showing a protective role for miR-199a. We further identified sirtuin 1 (SIRT1) as a direct target of miR-199a in alveolar macrophages, and the expression of SIRT1 was negatively correlated with the level of miR-199a. The protective role of miR-199a downregulation in LPS-stimulated alveolar macrophages and sepsis-induced ARDS could be attenuated by SIRT1 inhibitor. Taken together, these results indicate that downregulation of miR-199a might protect lung tissue against sepsis-induced ARDS by upregulation of SIRT1 through the suppression of excessive inflammatory responses and the inhibition of cellular apoptosis in lung tissue, suggesting its potential therapeutic effects on sepsis-induced ARDS.

BMP4 rs17563 polymorphism and nonsyndromic cleft lip with or without cleft palate: A meta-analysis

Background: Previous studies have investigated the relationship between human bone morphogenetic protein 4 gene (BMP4) rs17563 polymorphism and nonsyndromic cleft lip with or without cleft palate (NSCL/P). However, the results remained inconsistent. Therefore, we conducted a meta-analysis to assess the effect of BMP4 rs17563 polymorphism on NSCL/P. Methods: Electronic searches in 5 databases were conducted to select all eligible studies up to March 2017. Odds ratios (ORs) with the corresponding 95% confidence intervals (CIs) were calculated to estimate the association. Sensitivity analysis was performed to evaluate the results stability by excluding each study in turn. Publication bias was assessed by Begg funnel plots and Egger test. Results: A total of 11 case–control studies were included in the meta-analysis. The pooled frequency of the minor allele C for BMP4 rs17563 was lower in Asians (pooled frequencyu200a=u200a0.33, 95% CI: 0.29–0.37) than in Brazilian population (pooled frequencyu200a=u200a0.47, 95% CI: 0.40–0.54). The overall results showed no significant association of BMP4 rs17563 polymorphism with NSCL/P risk. However, the results turned out to be different when stratified by ethnicity. BMP4 rs17563 polymorphism was associated with a higher risk of NSCL/P among Asian ethnicity (C vs T: ORu200a=u200a1.33, 95% CI: 1.02–1.73; CC vs TT: ORu200a=u200a2.10, 95% CI: 1.28–3.43; CC vs TTu200a+u200aTC: ORu200a=u200a2.16, 95% CI: 1.34–3.47) and among Caucasian population (TC vs TT: ORu200a=u200a3.36, 95% CI: 2.03–5.54; TCu200a+u200aCC vs TT: ORu200a=u200a3.71, 95% CI: 2.43–5.69). Among Brazilian population, BMP4 rs17563 polymorphism exerted a significantly protective effect on NSCL/P (C vs T: ORu200a=u200a0.70, 95% CI: 0.58–0.84; CC vs TT: ORu200a=u200a0.54, 95% CI: 0.33–0.88; TC vs TT: ORu200a=u200a0.55, 95% CI: 0.44–0.69; TCu200a+u200aCC vs TT: ORu200a=u200a0.56, 95% CI: 0.45–0.69). Conclusion: The results suggest that the C allele of BMP4 rs17563 may be a risk factor for NSCL/P among Asians and Caucasians, and may be a protective factor for NSCL/P in Brazilian population. Future large-sample studies with appropriate designs among specific populations are warranted to evaluate the association.

Acetylation-Dependent Regulation of Notch Signaling in Macrophages by SIRT1 Affects Sepsis Development

SIRT1 is reported to participate in macrophage differentiation and affect sepsis, and Notch signaling is widely reported to influence inflammation and macrophage activation. However, the specific mechanisms through which SIRT1 regulates sepsis and the relationship between SIRT1 and Notch signaling remain poorly elucidated. In this study, we found that SIRT1 levels were decreased in sepsis both in vitro and in vivo and that SIRT1 regulation of Notch signaling affected inflammation. In lipopolysaccharide (LPS)-induced sepsis, the levels of Notch signaling molecules, including Notch1, Notch2, Hes1, and intracellular domain of Notch (NICD), were increased. However, NICD could be deacetylated by SIRT1, and this led to the suppression of Notch signaling. Notably, in macrophages from myeloid-specific RBP-J−/− mice, in which Notch signaling is inhibited, pro-inflammatory cytokines were expressed at lower levels than in macrophages from wild-type littermates and in RBP-J−/− macrophages, and the NF-κB pathway was also inhibited. Accordingly, in the case of RBP-J−/− mice, LPS-induced inflammation and mortality were lower than in wild-type mice. Our results indicate that SIRT1 inhibits Notch signaling through NICD deacetylation and thus ultimately alleviates sepsis.

Cell-free therapy based on adipose tissue stem cell-derived exosomes promotes wound healing via the PI3K/Akt signaling pathway

Introduction: Adipose tissue‐derived stem cells (ADSCs) have been shown to enhance wound healing via their paracrine function. Exosomes, as one of the most important paracrine factors, play an essential role in this process. However, the concrete mechanisms that underlie this effect are poorly understood. In this study, we aim to explore the potential roles and molecular mechanisms of exosomes derived from ADSCs in cutaneous wound healing. Methods: Normal human skin fibroblasts and ADSCs were isolated from patient skin and adipose tissues. ADSCs were characterized by using flow cytometric analysis and adipogenic and osteogenic differentiation assays. Exosomes were purified from human ADSCs by differential ultracentrifugation and identified by electron microscopy, nanoparticle tracking, fluorescence confocal microscopy and western blotting. Fibroblasts were treated with different concentrations of exosomes, and the synthesis of collagen was analyzed by western blotting; the levels of growth factors were analyzed by real‐time quantitative PCR (RT‐PCR) and ELISA; and the proliferation and migration abilities of fibroblasts were analyzed by real‐time cell analysis, CCK‐8 assays and scratch assays. A mouse model with a full‐thickness incision wound was used to evaluate the effect of ADSC‐derived exosomes on wound healing. The level of p‐Akt/Akt was analyzed by western blotting. Ly294002, a phosphatidylinositol 3‐kinases (PI3K) inhibitor, was used to identify the underlying mechanisms by which ADSC‐derived exosomes promote wound healing. Results: ADSC‐derived exosomes were taken up by the fibroblasts, which showed significant, dose‐dependent increases in cell proliferation and migration compared to the behavior of cells without exosome treatment. More importantly, both the mRNA and protein levels of type I collagen (Col 1), type III collagen (Col 3), MMP1, bFGF, and TGF‐&bgr;1 were increased in fibroblasts after stimulation with exosomes. Furthermore, exosomes significantly accelerated wound healing in vivo and increased the level of p‐Akt/Akt in vitro. However, Ly294002 alleviated these exosome‐induced changes, suggesting that exosomes from ADSCs could promote and optimize collagen deposition in vitro and in vivo and further promote wound healing via the PI3K/Akt signaling pathway. Conclusions: This study demonstrates that ADSC‐derived exosomes can promote fibroblast proliferation and migration and optimize collagen deposition via the PI3K/Akt signaling pathway to further accelerate wound healing. Our results suggest that ADSCs likely facilitate wound healing via the release of exosomes, and the PI3K/Akt pathway may play a role in this process. Our data also suggest that the clinical application of ADSC‐derived exosomes may shed new light on the use of cell‐free therapy to accelerate full‐thickness skin wound healing and attenuate scar formation. Graphical abstract Schematic diagram shows how the wound healing effect of ADSC‐Exos is mediated by the activation of the PI3K/Akt signaling pathways. Figure. No Caption available. HighlightsADSC‐Exos are internalized into HDFs and regulate their biological behaviors and functions.ADSC‐Exos play an important role in accelerating wound healing via activating PI3K/Akt signaling pathway.ADSC‐Exos may serve as a cell‐free therapy for the potential clinical treatment of wound healing.

Wild-type p53-modulated autophagy and autophagic fibroblast apoptosis inhibit hypertrophic scar formation

Hypertrophic scarring is a serious fibrotic skin disease, and the abnormal activation of hypertrophic scar fibroblasts (HSFs) intensifies its pathogenesis. Our previous studies have demonstrated that the dysregulation of autophagy in HSFs is associated with fibrosis. However, knowledge regarding the regulation of HS fibrosis by p53-modulated autophagy is limited. Here, we investigated the effect of p53-modulated autophagy on HS fibrosis. The overexpression of wtp53 (Adp53) promoted autophagic capacity and inhibited collagen and α-SMA expression in HSFs. In contrast, LC3 (AdLC3) overexpression did not suppress Col 1, Col 3, or α-SMA expression, but LC3 (shLC3) knockdown downregulated collagen expression. Adp53-modulated autophagy altered Bcl-2 and Bcl-xL expression, but AdLC3 affected only Bcl-xL expression. Silencing Bcl-xL suppressed collagen expression, but autophagy was also inhibited. Flow cytometry showed that the silencing of Bcl-2 (sibcl-2), Bcl-xL (sibcl-xL), and Adp53 significantly increased apoptosis in the HSFs. Therefore, wtp53 inhibited fibrosis in the HSFs by modulating autophagic HSF apoptosis; moreover, the inhibition of autophagy by sibcl-xL had antifibrotic effects. In addition, treatment with Adp53, AdLC3, shLC3, sibcl-2, and sibcl-xL reduced scar formation in a rabbit ear scar model. These data confirm that wtp53-modulated autophagy and autophagic HSF apoptosis can serve as potential molecular targets for HS therapy.The dysregulation of dermal fibroblast proliferation and apoptosis is thought to be related to hypertrophic scar formation. In this study, the authors show that the balance of autophagy in HSF is critical for fibrosis formation, and both downregulation and excessive upregulation of autophagy inhibits collagen expression via wild type p53 and the pro-survival protein Bcl-xL.

miR-155 inhibits the formation of hypertrophic scar fibroblasts by targeting HIF-1α via PI3K/AKT pathway

Hypertrophic scar (HS) is a serious skin fibrotic disease characterized by the excessive proliferation of fibroblasts and often considered as a kind of benign skin tumor. microRNA-155 (miR-155) is usually served as a promising marker in antitumor therapy. In view of the similarities of hypertrophic scar and tumor, it is predicted that miR-155 may be a novel therapeutic target in clinical trials. Here we found the expression levels of miR-155 was gradually down regulated and HIF-1α was upregulated in HS tissue and HS derived fibroblasts (HFs). And cell proliferation was inhibited when miR-155 was overexpressed or HIF-1α was silenced. Moreover, overexpression of miR-155 in HFs could reduce the expression of collagens in vitro and inhibit the collagen fibers arrangement in vivo, whereas miR-155 knockdown gave opposite results. Furthermore, we found that miR-155 directly targeted the HIF-1α, which could also independently inhibit the expression of collagens in vitro and obviously improved the appearance and architecture of the rabbit ear scar in vivo when it was silencing. Finally, we found that PI3K/AKT pathway was enrolled in these processes. Together, our results indicated that miR-155 was a critical regulator in the formation and development of hypertrophic scar and might be a potential molecular target for hypertrophic scar therapy.

MicroRNA-146a protects against LPS-induced organ damage by inhibiting Notch1 in macrophage

&NA; MicroRNA‐146a is a well‐studied microRNA participating in immune and inflammatory diseases, but its role in sepsis has not been investigated. Here in our study, we found increased level of microRNA‐146a in macrophage stimulated by lipopolysaccharide. In addition, the mRNA level of Notch1 was also increased. Up‐regulation of microRNA‐146a by miR‐146a‐mimic alleviated inflammatory responses of macrophage, for the levels of IL‐1&bgr;, IL‐6 and CCL‐2 were decreased, and the activation of NF‐&kgr;B signaling was inhibited. The histological examination showed that microRNA‐146a protected against organ damage in mice with lipopolysaccharide injection, and the level of inflammatory factors, Cr, BUN, AST and ALT in serum were all decreased, reflecting the alleviated inflammation and recovered organ function. Then predicting databases were used and Notch1 was predicted as one of the potential targets of microRNA‐146a. Knockout of Notch1 in macrophage showed reduced secretion of inflammatory factors and attenuated activation of NF‐&kgr;B signaling in response to lipopolysaccharide. Specifically knockout of Notch1 in macrophage protected mice from LPS induced organ damage and dysfunction. Therefore, we prove that miR‐146a acts as an inhibitor of inflammation by targeting Notch1 in macrophage, therefore protects mice from organ damage in sepsis. HighlightsLPS increased miR‐146a in macrophage.miR‐146a decreased inflammatory response of macrophage and protected against organ damage induced by LPS.miR‐146a directly targeted Notch1 to anti‐inflammation.

Linagliptin inhibits high glucose-induced trans-differentiation of hypertrophic scar derived fibroblasts to myofibroblasts via IGF/Akt/mTOR signaling pathway

Hypertrophic scar (HS) is a fibroproliferative disease after serious burns; the underlying mechanism remains unknown. The study was performed to clarify the effect of high glucose (HG) on HS. The expression of Col1, Col3 and α‐SMA was upregulated in HS‐derived fibroblasts (HSF) exposed to HG (20 and 30 mmol/L), and HG activated the phosphorylated protein expression of IGF/Akt/mTOR signalling pathway in HSF. Dpp4, a marker targeted the treatment of diabetes mellitus, was overexpressed in HG‐induced HSF. Linagliptin, a Dpp4 inhibitor, played the antifibrotic role in HSF exposed to HG, the levels of Col1, Col3 and α‐SMA were significantly downregulated, and the cell proliferation and migration were also inhibited. Furthermore, linagliptin alleviated the phosphorylated protein expression of IGF/Akt/mTOR signalling pathway. Moreover, the mTOR inhibitor (rapamycin) mimicked the effect of linagliptin on the collagen and α‐SMA that means linagliptin may inhibit HG‐induced transdifferentiation of HSF to myofibroblasts via IGF/Akt/mTOR signalling pathway.

MicroRNA-138 Aggravates Inflammatory Responses of Macrophages by Targeting SIRT1 and Regulating the NF-κB and AKT Pathways

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.