Background: Gut microbiota, which plays a crucial role in inflammatory bowel diseases (IBD), might have therapeutic benefits for ulcerative colitis or Crohn's disease. Targeting gut microbiota represents a new treatment strategy for IBD patients. Rhein is one of the main components of rhubarb and exhibits poor oral bioavailability but still exerts anti-inflammatory effects in some diseases. Therefore, we investigated the effect of rhein on colitis and studied its possible mechanisms. Methods: The chronic mouse colitis model was induced by four rounds of 2% dextran sulfate sodium (DSS) treatment. The mice were treated with 50 mg/kg and 100 mg/kg rhein daily, body weight, colon length, histological score, inflammatory cytokines in serum or intestine, and fecal lipocalin 2 concentration were determined. Th17 cell, Th1 cell and Th2 cell infiltration in the mesenteric lymph node were analyzed by flow cytometry. Metabolic profiles were collected by non-targeted metabolomics and key metabolic pathways were identified using MetaboAnalyst 4.0. We also assessed intestinal barrier permeability and performed 16s rDNA sequencing. Lactobacillus sp. was cultured, and fecal microbiota transplantation (FMT) was employed to evaluate the contribution of gut microbiota. Results: Rhein could significantly alleviate DSS-induced chronic colitis. Uric acid was identified as a crucial modulator of colitis and rhein treatment led to decreased uric acid levels. We determined that rhein changed purine metabolism indirectly, while the probiotic Lactobacillus was involved in the regulation of host metabolism. Uric acid resulted in a worsened intestinal barrier, which could be rescued by rhein. We further confirmed that rhein-treated gut microbiota was sufficient to relieve DSS-induced colitis by FMT. Conclusion: We showed that rhein could modulate gut microbiota, which indirectly changed purine metabolism in the intestine and subsequently alleviated colitis. Our study has identified a new approach to the clinical treatment of colitis.

EUS-FNA had overall excellent specificity and sensitivity in accurately diagnosing solid pancreatic masses. ROSE could help to improve the accuracy of diagnostic test.

Protein-protein interactions drive most every biological process, but in many instances the domains mediating recognition are disordered. How specificity in binding is attained in the absence of defined structure contrasts with well-established experimental and theoretical work describing ligand binding to protein. The signaling protein calmodulin presents a unique opportunity to investigate mechanisms for target recognition given that it interacts with several hundred different targets. By advancing coarsegrained computer simulations and experimental techniques, mechanistic insights were gained in defining the pathways leading to recognition and in how target selectivity can be achieved at the molecular level. A model requiring mutually induced conformational changes in both calmodulin and target proteins was necessary and broadly informs how proteins can achieve both high affinity and high specificity.coarse-grained molecular simulations | stopped-flow fluorescence techniques | conformational flexibility | hydrophobic motif | calmodulin binding target T he ubiquitous protein calmodulin (CaM) interacts with a vast selection of binding targets (CaMBTs); however, the molecular mechanisms that underlie target selectivity are not known despite an enormous wealth of structural information (1, 2). What emerges from this is the remarkable conformational flexibility of CaM, which exists in highly dynamic structures in the Ca 2+ free and bound forms (3-6) and will adopt distinct conformations when bound to protein targets. These distinct modes of binding are encoded by CaM-recognition motifs of targets that display impressive variability in amino acid sequence and are often partially or largely disordered in the absence of CaM. These data indicate that CaM-CaMBT interactions lie at the opposite end of the spectrum from the classic "lock and key" mechanism (7) initially proposed for rigid ligand binding to proteins, and require adopting more dynamic models, such as induced fit (8) or conformational selection (9). The induced-fit mechanism posits that productive binding occurs because the rigid ligand can alter the conformation of the enzyme, and that the final conformation exists only in the presence of ligand. Conformational selection assumes that the enzyme naturally samples a variety of conformational states and that the ligand binds to one, or a small subset, of these states. However, newer theories-termed extended conformational selection (10), mutually induced fit (11), fly-casting (12), or folding and binding (13, 14)-have begun to integrate molecule dynamics to describe folding and binding involving flexible molecules in protein-protein interactions, especially for the intrinsically disordered proteins (15-17) for which folding and binding are concomitant.The goal of the present study is to provide mechanistic insights at a molecular level into the time-dependent conformational adjustments between CaM and CaMBT for the binding mechanism. Results show that although CaM visits conformations similar to a target-boun...

BackgroundThe programmed cell death-1 receptor/programmed cell death-1 ligand (PD-1/PD-L1) pathway plays a crucial role in tumor evasion from host immunity. This study was designed to evaluate the association between circulating PD-L1/PD-1 and prognosis after cryoablation in patients with HBV-related hepatocellular carcinoma (HCC).Methodology/Principal FindingsIn the present study, 141 HBV-related HCC patients were enrolled and of those 109 patients received cryoablation. Circulating PD-L1/PD-1 expression was tested by flow cytometry, and 23 patients were simultaneously evaluated for intratumoral PD-L1 expression by immunohistochemical staining. Circulating PD-1/PD-L1 expression was associated with severity of diseases in patients with HCC, and the circulating PD-L1 expression was closely correlated with intratumoral PD-L1 expression. Of the clinical parameters, PD-1/PD-L1 expression was associated with tumor size, blood vessel invasion and BCLC staging. Moreover, PD-1/PD-L1 expression dropped after cryoablation while being elevated at the time of tumor recurrence. Patients with higher expression of circulating PD-L1, as well as circulating PD-1, had a significantly shorter overall survival and tumor-free survival than those with lower expression. Multivariate analysis confirmed that circulating PD-L1 could serve as an independent predictor of overall survival and tumor-recurrence survival in HCC patients after cryoablation.Conclusions/SignificanceUpregulation of circulating PD-L1/PD-1 is associated with poor post-cryoablation prognosis in patients with HBV-related hepatocellular carcinoma.

Background The cell fate determinant Numb is aberrantly expressed in cancer. Numb is alternatively spliced with one isoform containing an extended proline rich region (PRRL) compared to the other (PRRS). PRRL was recently reported to enhance proliferation of breast and lung cancer cells. However, the importance of Numb alternative splicing in hepatocellular carcinoma (HCC) remain unexplored. Main Results We report here that Numb PRRL expression is increased in HCC and is associated with early recurrence and reduced overall survival after surgery. In a panel of HCC cell lines, PRRL generally promotes and PRRS suppresses proliferation, migration, invasion and colony formation. PRRS knockdown leads to increased Akt phosphorylation and c-Myc expression, and Akt inhibition or c-Myc silencing dampens the proliferative impact of Numb PRRS knockdown. In the cell models explored in this study, alternative splicing of Numb PRR isoforms is coordinately regulated by the splicing factor Rbfox2 and the kinase SRPK2. Rbfox2 knockdown causes accumulation of PRRL while SRPK2 knockdown causes accumulation of PRRS. SRPK2 subcellular location is regulated by the molecular chaperone Hsp90, and Hsp90 inhibition or knockdown phenocopies SRPK2 knockdown in promoting accumulation of Numb PRRS. Finally, HCC cell lines that predominately express PRRL are differentially sensitive to Hsp90 inhibition. Conclusion Our data suggest that alternative splicing of Numb may provide a useful prognostic biomarker in HCC and is pharmacologically tractable.