Yijie Zhang

Up-regulation of FGFBP1 signaling contributes to miR-146a-induced angiogenesis in human umbilical vein endothelial cells

Recent microRNA expression profiling studies have documented an up-regulation of miR-146a in several angiogenesis models. However, the underlying molecular mechanism of miR-146a in the angiogenic activity of endothelial cells has not been clearly elucidated. The present study was aimed to evaluate whether miR-146a promotes angiogenesis in HUVECs by increasing FGFBP1 expression via directly targeting CREB3L1. miR-146a was over expressed in HUVECs via lentiviral-miR-146a. Expression profiling analysis found miR-146a over expression resulted in up-regulation of angiogenesis and cytokine activity associated genes including FGF2. Further a combination of bioinformatics and experimental analyses demonstrated the CREB3L1 as a bona fide functional target of miR-146a during angiogenesis. Moreover, CREB3L1 inhibited luciferase expression from FGFBP1 promoter containing only CRE elements. Furthermore, CREB3L1 inhibited FGFBP1 expression by binding to two CRE-like sites located at approximately −1780–1777 and −868–865 bp relative to the FGFBP1 transcription start site. Additionally, ectopic expression of CREB3L1 decreased miR-146a-induced FGF2 secretion. These findings indicate that the miR-146a-CREB3L1-FGFBP1 signaling axis plays an important role in the regulation of angiogenesis in HUVECs and provides a potential therapeutic target for anti-angiogenic therapeutics.

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.

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.

Curcumin pretreatment prevents hydrogen peroxide-induced oxidative stress through enhanced mitochondrial function and deactivation of Akt/Erk signaling pathways in rat bone marrow mesenchymal stem cells

Bone marrow mesenchymal stem cells (BMSCs)-based therapy has emerged as a desirable modality for the treatment of tissue injury with promising therapeutic effects; however, low survival rate of transplanted cells due to harsh microenvironment with hypoxia and oxidative stress results in hampered therapeutic benefits of this therapy. Curcumin, a natural bioactive product, is a dietary component which has gained increasing attention owing to its beneficial health properties. Here, we reported the protective effects of curcumin pretreatment on BMSCs injury induced by hydrogen peroxide (H2O2), which was used as ROS source of oxidative stress in vitro. We found that curcumin pretreatment remarkably inhibited H2O2-induced cell viability reduction, LDH leakage, and cell apoptosis in BMSCs. Moreover, curcumin pretreatment prevented H2O2-induced mitochondrial dysfunction via suppressing adenosine triphosphate loss, reactive oxygen species accumulation, and membrane potential decline. In addition, curcumin pretreatment markedly reduced the phosphorylation levels of Akt and Erk1/2. Taken together, our investigations demonstrated that curcumin pretreatment conferred BMSCs the ability to survive from H2O2-induced oxidative stress, which might attribute to its prevention of mitochondrial dysfunction and deactivation of Akt and Erk1/2 signaling pathways. Thus, this study sheds more light on the pharmacological mechanisms of curcumin, and suggests that BMSCs preconditioned with curcumin might be an effective way for cell therapy in tissue repair treatment.

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.

JAM-A knockdown accelerates the proliferation and migration of human keratinocytes, and improves wound healing in rats via FAK/Erk signaling

Junctional adhesion molecule-A (JAM-A) belongs to the immunoglobulin superfamily, it predominantly exists at the tight junctions of epithelial and endothelial cells. JAM-A is known to regulate leukocyte trans-endothelial migration, however, how it affects the proliferation and migration of keratinocytes, the two essential steps during wound healing, has less been explored. In this study, we showed that JAM-A was significantly expressed in normal skin epidermis. RNAi-mediated JAM-A knockdown remarkably promoted the proliferation and migration of keratinocytes. We also found that loss of JAM-A increased the protein levels of p-FAK, p-Erk1/2, and p-JNK; however, FAK inhibitor PF-562271 restrained the expression of p-FAK and p-Erk1/2 elevated by JAM-A RNAi, but not p-JNK, and also slowed down keratinocyte proliferation and migration. Finally, in a rat wound model we showed that absence of JAM-A significantly promoted the wound healing process, while the use of PF-562271 or Erk1/2 inhibitor PD98059 repressed those effects. These data collectively demonstrate that suppressing JAM-A expression could promote the proliferation and migration of keratinocytes and accelerate the healing process of rat skin wounds, potentially via FAK/Erk pathway, indicating that JAM-A might serve as a potential therapeutic target for the treatment of chronic refractory wounds.

A Randomized, Placebo-Controlled, Double-Blind, Prospective Clinical Trial of Botulinum Toxin Type A in Prevention of Hypertrophic Scar Development in Median Sternotomy Wound

BackgroundLinear hypertrophic scar is a common surgical problem that can be difficult to manage, especially for the median sternotomy scar. Botulinum toxin type A (BTA) is widely used in cosmetic surgery and has been shown to improve scar quality recently. The aim of this study was to evaluate the efficacy of BTA injected in the early postoperative of median sternotomy on preventing scar formation.MethodsIn this prospective randomized controlled trial, 19 consecutive patients who underwent median sternotomy were enrolled. The median sternotomy wound in each patient was divided into the upper half and the lower half. Both halves of the wound were randomized to receive the treatment with either BTA or normal saline. At 6-month follow-up, scars were assessed using the Vancouver Scar Scale, scar widths were measured, and patients were asked to evaluate their overall satisfaction.ResultsSeventeen patients with median sternotomy wounds completed the entire study. At 6-month follow-up, the mean Vancouver Scar Scale score for the BTA-treated group was 3.44 ± 1.68 and for the normal saline control group was 6.29 ± 2.39, and there was a statistically significant difference between the two groups (P < 0.05). There were also significant improvements in scar width and patient satisfaction for the BTA-treated halves of the wounds (P < 0.05).ConclusionsThe study demonstrates that early postoperative BTA injection can decrease scar formation and reduce scar width in median sternotomy wounds, and the overall appearance is more satisfactory.Level of Evidence IThis journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.