Colorectal cancer (CRC) is one of the most common cancer types and a leading cause of cancer-associated mortality in China. Increased thioredoxin reductase 1 (TrxR1) levels have been previously identified as possible target for CRC. The present study revealed that the natural product hydroxytyrosol (HT), which exhibits a polyphenol scaffold, is a potent inhibitor of TrxR1. Inhibition of TrxR1 was indicated to result in accumulation of reactive oxygen species, inhibit proliferation and induce apoptosis and G 1 /S cell cycle arrest of CRC cells. Using a C-terminal mutant TrxR1 enzyme activity assay, TrxR1 RNA interference assay and HT binding model assay, the present study demonstrated the core character of the selenocysteine residue in the interaction between HT and TrxR1. HT can serve as polyphenol scaffold to develop novel TrxR1 inhibitors for CRC treatment in the future.

Background: Accumulating evidence suggests that the polymerase I and transcript release factor (PTRF), a key component of the caveolae structure on the plasma membrane, plays a pivotal role in suppressing the progression of colorectal cancers. However, the role of PTRF in the development of functional gastrointestinal (GI) disorders remains unclear. Post-infectious irritable bowel syndrome (PI-IBS) is a common functional GI disorder that occurs after an acute GI infection. Here, we focused on the role of PTRF in the occurrence of PI-IBS and investigated the underlying mechanisms.Methods: Lipopolysaccharide (LPS) (5 μg/ml) was used to induce inflammatory injury in human primary colonic epithelial cells (HCoEpiCs). Furthermore, a rat model of PI-IBS was used to study the role of PTRF. Intestinal sensitivity was assessed based on the fecal water content. A two-bottle sucrose intake test was used to evaluate behavioral changes. Furthermore, shRNA-mediated knockdown of PTRF was performed both in vitro and in vivo. We detected the expression of PTRF in colonic mucosal tissues through immunohistochemistry (IHC), western blotting (WB), and immunofluorescence (IF) analysis. Luciferase activity was quantified using a luciferase assay. Co-localization of PTRF and Toll-like receptor 4 (TLR4) was detected using IF analysis. The activation of the signaling pathways downstream of TLR4, including the iNOs, p38, extracellular signal-regulated kinase (ERK), and c-Jun N-terminal kinase (JNK) pathways, was detected via WB. The levels of NO, IL-1β, IL-6, and TNF-α were measured using enzyme-linked immunosorbent assays.Results: LPS significantly induced PTRF expression and signaling downstream of TLR4, including p38, ERK, and JNK pathways, in HCoEpiCs. Moreover, shRNA-mediated knockdown of PTRF in HCoEpiCs significantly decreased the phosphorylation of JNK, ERK, and p38 and iNOS expression. In PI-IBS rats, the lack of PTRF not only reduced fecal water content and suppressed depressive behavior but also increased the body weight. Furthermore, we found a strong co-localization pattern for PTRF and TLR4. Consistently, the lack of PTRF impaired TLR4 signaling, as shown by the decreased levels of p-JNK, p-ERK, and p-p38, which are upstream factors involved in iNOS expression.Conclusion: PTRF promoted PI-IBS and stimulated TLR4 signaling both in vitro and in vivo. The results of this study not only enlighten the pathogenesis of PI-IBS but also help us understand the biological activity of PTRF and provide an important basis for the clinical treatment of PI-IBS by targeting PTRF.

As a key regulatory molecule in neurological disorders, the mechanism by which Rab10 exerts its protective effect in neuronal cells in depression is currently unknown. This research aimed to explore the function and mechanism of action of Rab10, a gene associated with neuroprotection, by using an in vitro model of depression. PC12 cells induced by corticosterone (CORT) were used to simulate depression in vitro. The viability of PC12 cells was detected using a CCK-8 assay, and the interaction between miRNA-103-3p and Rab10 was confirmed by bioinformatics combined with double luciferase and RNA Binding Protein Immunoprecipitation (RIP) experiments. The level of miRNA-103-3p and Rab10 were detected using a quantitative PCR assay. The protein contents of Rab10, BDNF, CREB, P62, Beclin-1, Wnt3a, GSK3β, phosphorylated (p)-GSK3β, and β-catenin were detected by western blotting. The results indicated that the content of Rab10 was downregulated in CUMS rats and CORT-induced PC12 cells. Bioinformatics combined with double luciferase and RIP experiments showed that miRNA-103-3p targeted Rab10. Overexpression of Rab10 or silencing of miRNA-103-3p in CORT-induced PC12 cells activated the Wnt/β-catenin signaling pathway, upregulated the contents of BDNF, CREB, and Beclin-1, but downregulated the expression of P62 protein, whereas silencing Rab10 based on silencing miRNA-103-3p reversed the effect of miRNA-103-3p. Overall, our data indicated that miRNA-103-3p targeted Rab10 to activate the Wnt/β-catenin signaling pathway to increase cellular nerve plasticity and promote autophagy, thus resisting CORT-induced damage to PC12 cells.

No abstract