Linkage-Editing Pseudo-Glycans: A Reductive α-Fluorovinyl-C-Glycosylation Strategy to Create Glycan Analogs with Altered Biological Activities.

The acetal (O-glycoside) bonds of glycans and glycoconjugates are chemically and biologically vulnerable, and therefore C-glycosides are of interest as more stable analogs. We hypothesized that, if the O-glycoside linkage plays a vital role in glycan function, the biological activities of C-glycoside analogs would vary depending on their substituents. Based on this idea, we adopted a "linkage-editing strategy" for the creation of glycan analogs (pseudo-glycans). We designed three types of pseudo-glycans with CH2 and CHF linkages, which resemble the O-glycoside linkage in terms of bond lengths, angles, and bulkiness, and synthesized them efficiently by means of fluorovinyl C-glycosylation and selective hydrogenation reactions. Application of this strategy to isomaltose (IM), an inducer of amylase expression, and α-GalCer, which activates iNKT cells, resulted in the discovery of CH2-IM, which shows increased amylase production ability, and CHF-α-GalCer, which shows activity opposite that of native α-GalCer, serving as an antagonist of iNKT cells.

Iridium-Catalyzed [2 + 2 + 2] Cycloaddition of Bithiophen-Linked Diynes with Nitriles: Scope and Mechanistic Study with Quantum Chemical Calculation.

We report a simple and atom-efficient method for the synthesis of bithiophene-fused isoquinolines by iridium-catalyzed [2 + 2 + 2] cycloaddition of bithiophene-linked diynes with nitriles. All three structural isomers of bithiophene-linked diynes underwent [2 + 2 + 2] cycloaddition, and the trend in the reactivity for cycloaddition was diyne 1 = diyne 3 > diyne 2. Dibenzothiophene-linked diyne also reacted with nitriles to form a variety of cycloadducts. Cycloaddition of bithiophene-linked diynes with alkynes and an isocyanate formed naphthodithiophenes and a 2-pyridone derivative, respectively. Cycloadducts bearing a 2-aminopyridine moiety and benzothiophene rings showed intense fluorescence at around 530 nm and gave a fluorescence quantum yield of 0.44. Furthermore, quantum chemical calculations provided insight into the origin of the difference in reactivity of three bithiophene-linked diynes. The different reactivities of the three diynes 1-3 are believed to originate from the step where an iridacyclopentadiene reacts with a coordinated nitrile to form azairidabicyclo[3.2.0]heptatriene. HOMOs of iridacyclopentadiene play a decisive role in this step.

Initial tumor size and narrow-band image findings estimate growth speed in duodenal tumors.

INTRODUCTION: Recently, detection of superficial non-ampullary duodenal epithelial tumors (SNADETs) including adenomas and superficial duodenal carcinomas has increased. Various endoscopic treatment methods have also been reported for SNADETs, but there are few reports on the natural history. The aim of this study was to analyze factors related to tumor growth and determine the characteristics of SNADETs which need early therapeutic intervention. METHODS: A single-center, retrospective study was performed on medical records of 309 patients with SNADETs who underwent endoscopic or surgical resection between January 2010 and May 2021. Of these, 41 patients who were followed up for more than one year by endoscopy were analyzed. The primary outcome was analysis of the tumor growth speed. Secondary outcomes were the relationship between the tumor growth speed and mucin phenotype, tumor size and findings of magnifying endoscopy with narrow-band imaging (M-NBI). RESULTS: The observation period was 24 months (13-182). Tumor growth speed was 1.1 mm/year (0-21.6). Tumor diameter >10 mm at first detection (P=0.004; Odds ratio 19.5(2.03-186.96)) and mixed-type by M-NBI (p=0.036; Odds ratio 9.69(1.05-89.88)) were identified as risk factors of tumors growing at a rate of >3 mm/year. There was no statistically significant difference in the speed of tumor growth between the different mucin immunohistochemical phenotype. CONCLUSION: Initial tumor size and findings of M-NBI are useful to predict tumor growth and consider early intervention.

Long-Term Monitoring and Clinical Implications of Small Bowel Capsule Endoscopy in Patients with Crohn's Disease with Small Bowel Lesions: A Retrospective Analysis.

INTRODUCTION: Crohn's disease (CD) induces persistent inflammation throughout the gastrointestinal (GI) tract, potentially resulting in complications such as intestinal stenosis and fistulas, particularly in the small bowel. Small bowel capsule endoscopy (SBCE) is recommended for monitoring CD, especially when GI tract patency is maintained. This study aimed to retrospectively assess patients with CD who underwent SBCE to determine the timing of clinical changes and address the current lack of evidence regarding GI tract patency loss during CD treatment. METHODS: Of the 166 consecutive patients who underwent SBCE at our institution, 120 were followed up and included in this study. Forty-six patients were excluded due to colitis type or immediate treatment changes post-SBCE. This study focused on the primary and secondary endpoints, including the cumulative stricture-free rate of the GI tract, emergency hospitalization post-SBCE, and post-SBCE treatment strategies, at the discretion of the attending physicians. RESULTS: Demographic data revealed that the mean age of the study population was 43 years and that there was a male predominance (75%). The median disease duration was 12 years and the mean Crohn's Disease Activity Index was 98. During a 1,486-day observation period, 37% of patients experienced treatment changes. A Lewis score of >264 and perianal lesions were identified as independent risk factors for additional treatment needs. Emergency hospitalization occurred in 6% of patients and GI patency failure in 11%. Female sex and Lewis score>264 were associated with higher risks. GI patency rate declined 2 years after SBCE. CONCLUSIONS: For patients who experienced no treatment changes based on SBCE results, it is recommended to undergo SBCE monitoring at intervals of no longer than 2 years.

Analysis of Neuropeptides in the Intestinal Mucus of Patients with Ulcerative Colitis Using RNA Sequencing.

INTRODUCTION: Inflammation in ulcerative colitis (UC) originates in the colorectal mucosa. Transcriptome sequencing analysis of the colorectal mucosa allows the identification of potential neuropeptides related to local neurotransmission. The intestinal mucus lining the surface of the mucosa may harbor biomarkers of mucosal inflammation; however, this has not been sufficiently investigated, given the difficulty in obtaining human samples. We previously reported the feasibility of obtaining mucin samples for proteomic analysis by brushing during colonoscopy. Herein, we aimed to investigate the composition of the intestinal mucus and detect neuropeptides characteristic of UC. METHODS: Mucus and mucosal samples were collected from patients with UC from the colorectum in areas showing remission or active UC using a brush catheter and biopsy forceps during colonoscopy. RNA sequencing findings of mucus samples of active and remission areas were compared. RNA and protein expression levels of significantly upregulated neuropeptides were analyzed. RESULTS: Of the neuropeptides associated with UC, somatostatin (SST) was significantly elevated in areas of remission, according to RNA sequencing results of mucus and expression levels in mucus RNA and proteins. Conversely, SST expression in the mucosa was increased in the inflamed areas. Flow cytometry revealed that the fluorescence intensity of SST-positive cells in the remission zone was higher in the mucus than in the mucosa. CONCLUSION: SST expression in the mucus is considered to be an important factor associated with UC activity.

Monoclonal Antibodies Against Mature Interleukin-18 Ameliorate Colitis and Repair Goblet Cell Function.

BACKGROUND: Numerous biological interventions and small molecules are used to treat Crohn's disease; however, the effectiveness of these treatments varies largely. Non-responsiveness to biological therapies is associated with interleukin (IL)-18 gene polymorphisms and high IL-18 expression has been implicated in the pathogenesis of Crohn's disease. AIMS: The aim of this study was to elucidate the expression of precursor and mature IL-18 in patients with Crohn's disease who exhibited varied responses to cytokine-targeted treatments and determine whether selective inhibition of mature IL-18 offers a novel therapeutic avenue. METHODS: We generated a monoclonal antibody that specifically recognizes the neoepitope of caspase-cleaved mature IL-18. Expression of precursor and mature IL-18 was analyzed in patients with Crohn's disease. Anti-mature IL-18 monoclonal antibodies were intraperitoneally administered in an acute colitis mouse model, and the disease activity index, body weight loss, tissue pathology, proinflammatory cytokine expression, goblet cell function, and microbiota composition were assessed. RESULTS: Precursor and mature IL-18 expression was upregulated and goblet cell function was impaired in patients with Crohn's disease who were unresponsive to biological therapies. Administration of anti-mature IL-18 antibodies ameliorated induced colitis by repairing goblet cell function and restoring the mucus layer. CONCLUSIONS: The newly developed monoclonal antibody holds promise as a therapeutic alternative for Crohn's disease.

Evaluation of the Accuracy of Intraocular Lens Power Calculation Formulas in Phacovitrectomy.

INTRODUCTION: The aim of this study was to evaluate the refractive error in patients undergoing combined phacovitrectomy with and without gas tamponade. METHODS: This was a retrospective chart review including patients undergoing phacoemulsification alone (Group 1), combined phacovitrectomy for epiretinal membrane (Group 2), and combined phacovitrectomy with gas tamponade for rhegmatogenous retinal detachment (RRD) (Group 3). Axial length and keratometry were measured using an optical biometric system (Argos, Alcon Laboratories. Inc.), and a three-piece intraocular lens (IOL; NX-70S) was implanted in all groups. In each group, the prediction error at 3 months was calculated using IOL power calculation formulas (SRK/T, Hill-RBF, Kane, and Barrett Universal II) for each eye. Outcome measures included the mean prediction error (MPE), its standard deviation (SD), and the mean absolute error (MAE). The change in IOL position at 3 months was also assessed using anterior segment optical coherence tomography. RESULTS: A total of 104 eyes were included (Group 1: 30; Group 2: 34; Group 3: 40 eyes). The MPE was -0.08 ± 0.37 diopters (D), -0.26 ± 0.32 D, and -0.59 ± 0.34 D in Group 1, Group 2, and Group 3, respectively, using the Barrett Universal II formula (P < 0.01, ANOVA). The movement forward in the IOL position was 0.95 ± 0.16 mm, 0.94 ± 0.12 mm, and 1.07 ± 0.20 mm in Group 1, Group 2, and Group 3, respectively (P < 0.01). No significant difference was shown in MPE among the four formulas after combined phacovitrectomy with gas (P = 0.531). CONCLUSIONS: Phacovitrectomy in RRD induced a significant myopic shift using any of the clinically available formulas. This suggests that myopic shift should be taken into consideration for better refractive outcomes in phacovitrectomy with gas tamponade in RRD.

Early acquisition of S-specific Tfh clonotypes after SARS-CoV-2 vaccination is associated with the longevity of anti-S antibodies.

SARS-CoV-2 vaccines have been used worldwide to combat COVID-19 pandemic. To elucidate the factors that determine the longevity of spike (S)-specific antibodies, we traced the characteristics of S-specific T cell clonotypes together with their epitopes and anti-S antibody titers before and after BNT162b2 vaccination over time. T cell receptor (TCR) αß sequences and mRNA expression of the S-responded T cells were investigated using single-cell TCR- and RNA-sequencing. Highly expanded 199 TCR clonotypes upon stimulation with S peptide pools were reconstituted into a reporter T cell line for the determination of epitopes and restricting HLAs. Among them, we could determine 78 S epitopes, most of which were conserved in variants of concern (VOCs). After the 2nd vaccination, T cell clonotypes highly responsive to recall S stimulation were polarized to follicular helper T (Tfh)-like cells in donors exhibiting sustained anti-S antibody titers (designated as 'sustainers'), but not in 'decliners'. Even before vaccination, S-reactive CD4+ T cell clonotypes did exist, most of which cross-reacted with environmental or symbiotic microbes. However, these clonotypes contracted after vaccination. Conversely, S-reactive clonotypes dominated after vaccination were undetectable in pre-vaccinated T cell pool, suggesting that highly responding S-reactive T cells were established by vaccination from rare clonotypes. These results suggest that de novo acquisition of memory Tfh-like cells upon vaccination may contribute to the longevity of anti-S antibody titers.

Sulfated bile acid is a host-derived ligand for MAIT cells.

Mucosal-associated invariant T (MAIT) cells are innate-like T cells that recognize bacterial riboflavin-based metabolites as activating antigens. Although MAIT cells are found in tissues, it is unknown whether any host tissue-derived antigens exist. Here, we report that a sulfated bile acid, cholic acid 7-sulfate (CA7S), binds the nonclassical MHC class I protein MR1 and is recognized by MAIT cells. CA7S is a host-derived metabolite whose levels were reduced by more than 98% in germ-free mice. Deletion of the sulfotransferase 2a family of enzymes (Sult2a1-8) responsible for CA7S synthesis reduced the number of thymic MAIT cells in mice. Moreover, recognition of CA7S induced MAIT cell survival and the expression of a homeostatic gene signature. By contrast, recognition of a previously described foreign antigen, 5-(2-oxopropylideneamino)-6-d-ribitylaminouracil (5-OP-RU), drove MAIT cell proliferation and the expression of inflammatory genes. Thus, CA7S is an endogenous antigen for MAIT cells, which promotes their development and function.

Monoclonal Antibody Against Mature Interleukin-18 Ameliorates Colitis in Mice and Improves Epithelial Barrier Function.

BACKGROUND: Antitumor necrosis factor (TNF)-α antibodies have improved the outcome of inflammatory bowel disease (IBD); but half of patients remain unresponsive to treatment. Interleukin-18 (IL-18) gene polymorphism is associated with resistance to anti-TNF-α antibodies, but therapies targeting IL-18 have not been clinically applied. Only the mature protein is biologically active, and we aimed to investigate whether specific inhibition of mature IL-18 using a monoclonal antibody (mAb) against a neoepitope of caspase-cleaved mature IL-18 could be an innovative treatment for IBD. METHODS: The expression of precursor and mature IL-18 in patients with UC was examined. Colitis was induced in C57/BL6 mice by administering dextran sulfate sodium (DSS), followed by injection with anti-IL-18 neoepitope mAb. Colon tissues were collected and subjected to histological analysis, immunohistochemistry, immunoblotting, and quantitative polymerase chain reaction. Colon epithelial permeability and microbiota composition were analyzed. RESULTS: Mature IL-18 expression was elevated in colon tissues of patients with active ulcerative colitis. Administration of anti-IL-18 neoepitope mAb ameliorated acute and chronic DSS-induced colitis; reduced interferon-γ, TNF-α, and chemokine (CXC motif) ligand-2 production and epithelial cell permeability; promoted goblet cell function; and altered the intestinal microbiome composition. The suppressive effect of anti-IL-18 neoepitope mAb was superior to that of anti-whole IL-18 mAb. Furthermore, combination therapy with anti-TNF-α Ab suppressed acute and chronic colitis additively by suppressing cytokine expressions and reducing cell permeability by upregulating claudin1 and occludin expression. CONCLUSIONS: Anti-IL-18 neoepitope mAb ameliorates acute and chronic colitis, suggesting that this mAb will be an innovative therapeutic option for IBD.

We investigate a novel monoclonal antibody that specifically recognizes a neoepitope of caspase-cleaved IL-18 and alleviates dextran sulfate sodium-induced colitis by suppressing the secretion of inflammatory cytokines, improving intestinal epithelial permeability, promoting goblet cell function, and regulating intestinal microbiota.