Yufeng Li

The intestinal barrier is crucial for homeostasis. This study aimed to investigate the protective effects of earthworm protein hydrolysates (EWPH) on the intestinal mucosal barrier and elucidate the underlying mechanisms. We first hydrolyzed earthworm protein using alcalase and identified the primary peptide components of EWPH through Nano LC-MS/MS analysis. Network pharmacology and bioinformatics approaches were employed to predict potential targets associated with the intestinal mucosal barrier. Experimentally, we demonstrated that EWPH effectively protects against DSS-induced intestinal barrier damage in mice. The protective mechanisms involve not only the inhibition of the TLR4-NF-κB/MAPK signaling pathway in the intestinal epithelium but also the suppression of other key molecules implicated in intestinal mucosal barrier damage, including p-SRC, p-STAT3, Caspase-3, and MMP9, thereby mitigating intestinal inflammation and mucosal barrier injury. This study provides evidence that EWPH have the potential to safeguard the intestinal barrier hemostasis.

Background: Glioblastoma (GBM) is the most aggressive brain tumor. Reportedly, circular RNAs (circRNAs) participate in regulation of the development and progression of diverse cancers, including GBM.Methods: Dysregulated circRNAs in GBM tissues were screened out from GEO database. The expression of candidate circRNAs in GBM cells was measured by qRT‐PCR. Loss‐of function assays, including colony formation assay, EdU assay, TUNEL assay, and flow cytometry analysis were conducted to determine the effects of circ‐AHCY knockdown on GBM cell proliferation and apoptosis. Animal study was further used to prove the inhibitory effect of circ‐AHCY silencing on GMB cell growth. Mechanistic experiments like luciferase reporter, RNA pull‐down and RNA‐binding protein immunoprecipitation (RIP) assays were performed to unveil the downstream molecular mechanism of circ‐AHCY. Nanosight Nanoparticle Tracking Analysis (NTA) and PKH67 staining were applied to identify the existence of exosomes.Results: Circ‐AHCY was confirmed to be highly expressed in GBM cells. Circ‐AHCY silencing suppressed GBM cell proliferation both in vitro and in vivo. Mechanistically, circ‐AHCY activates Wnt/β‐catenin signaling pathway by sequestering miR‐1294 to up‐regulate MYC which activated CTNNB1 transcription. It was also found that circ‐AHCY recruited EIF4A3 to stabilize TCF4 mRNA. Enhanced levels of TCF4 and β‐catenin contributed to the stability of TCF4/β‐catenin complex. In turn, TCF4/β‐catenin complex strengthened the transcriptional activity of circ‐AHCY. Exosomal circ‐AHCY derived from GBM cells induced abnormal proliferation of normal human astrocytes (NHAs).Conclusion: Exosomal circ‐AHCY forms a positive feedback loop with Wnt/β‐catenin signaling pathway to promote GBM cell growth.

The occurrence rate of v-raf murine sarcoma viral oncogene homolog B1 (BRAF) activating mutation V600E (BRAF^V600E) in glioblastoma multiforme (GBM) is more than 50%. Na/H exchanger 1 (NHE1), a main pH regulator affecting cell microenvironment, is hyper-expressed in GBM. However, the relationship between BRAF^V600E signal pathway and NHE1 in GMB cells remains unclear. This study found that NHE1 was a downstream target of BRAF^V600E and an upstream factor of extracellular signal-regulated kinase (ERK). In addition, there was a positive feedback loop between NHE1-ERK phosphorylation under regulation of BRAF^V600E mutation contributing to the proliferation and invasion of GBM cells. Moreover, the proliferation and invasion abilities of BRAF^V600E-mutant and BRAF wild type GBM cells were all suppressed by the NHE1 inhibitor, BRAF^V600E inhibitor and combination of them. The inhibitory effect of combination of the two inhibitors was better than each single drug both in vitro and in vivo. Combination of BRAF^V600E and NHE1 inhibitors could be considered as a new therapeutic regimen for GBM, especially for GBM with BRAF^V600E.