Our previous studies have demonstrated that ubiquitin-specific peptidase 22 (USP22) has the capacity to accelerate renal epithelial-to-mesenchymal transition (EMT) and promote the pathological progression of diabetic tubulointerstitial fibrosis (TIF) by regulating the ubiquitination of Snail1, an EMT transcription factor. Quercetin is a type of flavonol compound widely found in fruits and vegetables that has anti-inflammatory, antioxidant and anti-fibrosis effects. However, whether quercetin promotes the degradation of Snail1 and regulates the pathological progression of TIF by inhibiting USP22 requires further investigation. In this study, we found that quercetin significantly inhibited the expression of USP22 and Snail1 in high glucose (HG)-induced renal tubular epithelial cells (TECs), and reversed the expression of EMT-related proteins and inhibited the overproduction of fibronectin (FN) and Collage Type IV (Collagen IV) induced by high glucose. Additionally, quercetin blocked the deubiquitination of Snail1 mediated by USP22. Further study found that quercetin inhibited the interaction between USP22 and Snail1, thereby reducing the stability of Snail1. Furthermore, quercetin also reduced the protein levels of USP22 and Snail1 in the kidney tissue of diabetic mice and ameliorated renal function, delayed EMT and TIF. In conclusion, quercetin regulates the USP22-Snail1 signal pathway to inhibit the occurrence of EMT both in vitro and in vivo, and ultimately ameliorate the pathological progress of TIF.
Liang Wang,Jinsong Li,Mingshan Jiang,Yue Luo,Xiaoke Xu,Juan Li,Yang Pan,Hu Zhang,Zhi-Xiong Jim Xiao,Yang Wang
Background and Aims Dysfunction of the intestinal epithelial barrier comprising the junctional complex of tight junctions and adherent junctions leads to increased intestinal permeability, which is a major cause of uncontrolled inflammation related to Inflammatory Bowel Disease (IBD). The NAD + -dependent deacetylase SIRT1 is implicated in inflammation and the pathological process of IBD. We aimed to elucidate the protective role and underlying mechanism of SIRT1 in cell-cell junction and intestinal epithelial integrity. Methods The correlation of SIRT1 expression and human IBD was analyzed by GEO or immunohistochemical analyses. BK5.mSIRT1 transgenic mice and WT mice were given dextran sodium sulfate (DSS) and the manifestation of colitis-related phenotypes were analyzed. Intestinal permeability was measured by FITC-Dextran and cytokines expression was analyzed by QPCR. The expression of the cell junction-related proteins in DSS-treated or SIRT1-knockdown Caco2 or HCT116 cells was analyzed by Western blotting. The effects of Nicotinamide mononucleotide (NMN) in DSS-induced mice colitis were investigated. Correlations of the SIRT1-β-TrCP1-Snail1-Occludin/Claudin-1/E-cadherin pathway with human IBD samples were analyzed. Results Reduced SIRT1 expression is associated with human IBD specimens. SIRT1 transgenic mice exhibit much-reduced manifestations of DSS-induced colitis. the activation of SIRT1 by NMN bolsters intestinal epithelial barrier function and ameliorates DSS-induced colitis in mice. Mechanistically, DSS down-regulates SiRT1 expression, leading to destabilization of β-TrCP1 and upregulation of Snail1, accompanied by reduced expression of E-cadherin, Occludin, and Claudin-1, consequently resulting in increased epithelial permeability and inflammation. The deregulated SIRT1-β-TrCP1-Snail1-Occludin/Claudin-1/E-cadherin pathway correlates with human IBD. Conclusion SIRT1 is pivotal in maintaining the intestinal epithelial barrier integrity via modulation of the β-TrCP1-Snail1-E-cadhein/Occludin/Claudin-1 pathway.
Xiaomeng Wang,Xiaoduo Tang,Nuo Li,Yihan Sun,Ruotong Yu,Junhu Zhang,Daowei Li,Bai Yang,Hongchen Sun
The ultimate goal of cutaneous wound healing is to reform a stratified epithelium to restore the normal epidermal barrier, which involves the epithelial-to-mesenchymal transition (EMT) process. However, healing strategies based on EMT induction are immature and ambiguous to date. Excessive induction of EMT may cause fibrosis, hypertrophic scarring, and increased risk of malignancy. Here, we present a new EMT-inducing strategy for eliciting partial EMT to facilitate proper epithelial cell migration. The new EMT-inducing system integrates black phosphorus nanosheets (BPNSs), catechol-modified chitosan (CA-CS), and oxidized dextran (Odex) to engineer an adhesive hydrogel patch (C&BP-Patch) with remarkable efficacy on infectious burn wound healing. The C&BP-Patch can orchestrate key early skin wound healing processes including hemostasis, inflammation, and proliferation, which enable fast partial EMT induction to restore an intact epithelial barrier. The C&BP-Patch acts initially as a high-performance bio-sealant to create a moist and stable microenvironment for EMT. Moreover, the photothermal effects of the C&BP-Patch can eliminate bacteria, accelerate microcirculation and reduce inflammation to maintain a proper EMT. Most importantly, the BPNSs can intrinsically induce partial EMT of epithelial cells via a Snail1-mediated signaling pathway. Therefore, our study proposes a new strategy for effective infectious burn wound healing based on inducing partial EMT.
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