Regulation of MAIT cells through host-derived antigens.

Mucosal-associated invariant T (MAIT) cells are a major subset of innate-like T cells that function at the interface between innate and acquired immunity. MAIT cells recognize vitamin B2-related metabolites produced by microbes, through semi-invariant T cell receptor (TCR) and contribute to protective immunity. These foreign-derived antigens are presented by a monomorphic antigen presenting molecule, MHC class I-related molecule 1 (MR1). MR1 contains a malleable ligand-binding pocket, allowing for the recognition of compounds with various structures. However, interactions between MR1 and self-derived antigens are not fully understood. Recently, bile acid metabolites were identified as host-derived ligands for MAIT cells. In this review, we will highlight recent findings regarding the recognition of self-antigens by MAIT cells.

Metal-Halide Covalency, Exchange Coupling, and Slow Magnetic Relaxation in Triangular (CpiPr5)3U3X6 (X = Cl, Br, I) Clusters.

The actinide elements are attractive alternatives to transition metals or lanthanides for the design of exchange-coupled multinuclear single-molecule magnets. However, the synthesis of such compounds is challenging, as is unraveling any contributions from exchange coupling to the overall magnetism. To date, only a few actinide compounds have been shown to exhibit exchange coupling and single-molecule magnetism. Here, we report triangular uranium(III) clusters of the type (CpiPr5)3U3X (1-X; X = Cl, Br, I; CpiPr5 = pentaisopropylcyclopentadienyl), which are synthesized via reaction of the aryloxide-bridged precursor (CpiPr5)2U2(OPhtBu)4 with excess Me3SiX. Spectroscopic analysis suggests the presence of covalency in the uranium-halide interactions arising from 5f orbital participation in bonding. The dc magnetic susceptibility data reveal the presence of antiferromagnetic exchange coupling between the uranium(III) centers in these compounds, with the strength of the exchange decreasing down the halide series. Ac magnetic susceptibility data further reveal all compounds to exhibit slow magnetic relaxation under zero dc field. In 1-I, which exhibits particularly weak exchange, magnetic relaxation occurs via a Raman mechanism associated with the individual uranium(III) centers. In contrast, for 1-Br and 1-Cl, magnetic relaxation occurs via an Orbach mechanism, likely involving relaxation between ground and excited exchange-coupled states. Significantly, in the case of 1-Cl, magnetic relaxation is sufficiently slow such that open magnetic hysteresis is observed up to 2.75 K, and the compound exhibits a 100-s blocking temperature of 2.4 K. This compound provides the first example of magnetic blocking in a compound containing only actinide-based ions, as well as the first example involving the uranium(III) oxidation state.

Differentiation of ovarian serous carcinoma from ovarian clear cell carcinoma using a 10-gene signature selected by comprehensive gene expression analysis.

AIM: Ovarian serous carcinoma (OSC) and ovarian clear cell carcinoma (OCCC) are two major histological types of epithelial ovarian carcinoma (EOC), each with different biological features and clinical behaviors. Although immunostaining is commonly used for differential diagnosis between OSC and OCCC, correct identification of EOC with mixed-type histology is sometimes a diagnostic challenge. The aim of the present study was to explore candidate genes as potential diagnostic biomarkers that distinguish OSC from OCCC. METHODS: A total of 57 surgical specimens were obtained from EOC patients who had previously undergone primary debulking surgery. Total RNAs were extracted from fresh-frozen tissues of EOC patients, and were used for comprehensive gene expression analysis using DNA microarray technology. RESULTS: Ten candidate genes, FXYD2, TMEM101, GABARAPL1, ARG2, GLRX, RBPMS, GDF15, PPP1R3B, TOB1, and GSTM3 were up-regulated in OCCC compared to OSC. All EOC patients were divided into two groups according to hierarchical clustering using a 10-gene signature. CONCLUSION: Our data suggest that the 10 candidate genes would be an excellent marker for distinguishing OSC from OCCC. Furthermore, the molecular signatures of the 10 genes may enlighten us on the differences in carcinogenesis, and provide a theoretical basis for OCCC's resistance to chemotherapy in the future.

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.

Retrospective observational study of a novel smartphone app on the management of patients with mild cognitive impairment or mild dementia.

Introduction: In this study, we aimed to evaluate the feasibility, utility, and potential effects of LQ-M/D App, a smartphone application developed by Life Quest Inc., Tokyo, Japan, for patients with mild cognitive impairment (MCI) and mild dementia. The app incorporates cognitive and physical exercise training, lifestyle habit acquisition features, and a continuity improvement feature added in the post-update version to enhance user engagement. The continuity improvement feature includes the optimization of training content, and disease education, and enables family monitoring via a family app. Methods: A retrospective analysis was conducted on app usage, cognitive and exercise training implementation and interruptions, questionnaire response rates, and cognitive assessments in a single institution. A total of 20 patients used the app, with 10 patients using the pre-update version without the continuity improvement feature, and the other 10 patients using the post-update version with the continuity improvement feature. Results and Conclusion: The results demonstrated that the LQ-M/D App could be effectively used by the study population, and the continuity improvement feature positively influenced app usage in several aspects. Although a potential association between app usage and cognitive ability was suggested, the scatter in the data points warrants cautious interpretation. Limitations of the study included a small sample size, a single institution setting, and the retrospective nature of the study. In the future, a randomized controlled trial design using a larger sample size and multiple institutions to further evaluate the effectiveness of LQ-M/D App in managing MCI and mild dementia should be performed.

Archaeal Glycerolipids Are Recognized by C-Type Lectin Receptor Mincle.

Recently, various metabolites derived from host microbes have been reported to modulate the immune system, with potential involvement in health or diseases. Archaea, prokaryotic organisms, are present in the human body, but their connection with the host is largely unknown when compared to other microorganisms such as bacteria. This study focused on unique glycerolipids from symbiotic methanogenic archaea and evaluated their activities toward an innate immune receptor. The results revealed that archaeal lipids were recognized by the C-type lectin receptor Mincle and induced immune responses. A concurrent structure-activity relationship study identified the key structural features of archaeal lipids required for recognition by Mincle. Subsequent gene expression profiling suggested qualitative differences between the symbiotic archaeal lipid and the pathogenic bacteria-derived lipid. These findings have broad implications for understanding the function of symbiotic archaea in host health and diseases.

Gallbladder fossa nodularity in the liver typically observed in patients with alcoholic liver disease; comparison with chronic hepatitis C patients.

BACKGROUND AND PURPOSE: Gallbladder fossa nodularity (GBFN) is often observed in patients with alcoholic liver disease (ALD), and we hypothesized this may be due to the cholecystic venous drainage (CVD), sparing this area from portal perfusion containing alcohol absorbed in the alimentary tract, and also escaping from alcohol-induced fibrotic and atrophic change of the liver parenchyma. The purpose of this study is to verify our hypothesis, using chronic hepatitis C (CHC) patients as a control. MATERIALS AND METHODS: Between 2013 and 2017, consecutive 45 ALD and 46 CHC patients who had contrast-enhanced CT were retrospectively recruited. Those who had interventions or disease involvement around gallbladder fossa were excluded. All CT images, and angiography-assisted CT(ang-CT) images , when available, were reviewed. GBFN was subjectively classified into grades 0-3, depending upon the conspicuity of nodularity, which was compared between the groups, and was also correlated to various clinicoradiological factors, including the alcohol consumption grades (ACG). RESULTS: GBFN was more frequently observed in ALD than in CHC patients, and higher grade GBFN was associated with ALD rather than CHC (all p < 0.05). Multivariable analysis revealed independently significant factors related to GBFN grades were ACG and albumin-bilirubin grades. Ang-CT images were available in 11 patients, all of whom exhibited portal perfusion diminishment and faint arterial enhancement, suggesting CVD, at the region of GBFN. When GBFN grade 3 was considered to discriminate ALD from CHC, the value of sensitivity/specificity/accuracy is 9%/100%/55%. CONCLUSION: GBFN may represent spared liver tissue from alcohol-containing portal venous perfusion due to CVD, which may serve as an adjunctive sign of ALD or alcohol overconsumption with high specificity, but low sensitivity.

Supervalence Bonding in Bi-icosahedral Cores of [M1Au37(SC2H4Ph)24]- (M = Pd and Pt): Fusion-Mediated Synthesis and Anion Photoelectron Spectroscopy.

Au38(PET)24 (PET = SC2H4Ph) is known to have a bi-icosahedral Au23 core consisting of two Au13 icosahedrons by sharing three Au atoms. Previous theoretical studies based on a supervalence bond (SVB) model have demonstrated that the bonding scheme in the Au23 core is similar to that in the F2 molecule. The SVB model predicted that the electron configuration of the Au23 core with 14 valence electrons is expressed as (1Σ)2(1Σ*)2(1Π)4(2Σ)2(1Π*)4 where each orbital is created by the bonding and antibonding interactions between the 1S and 1P superatomic orbitals of the icosahedral Au13 units. Therefore, the bi-icosahedral Au23 can be viewed as a di-superatomic molecule. To validate the SVB model, we herein conducted anion photoelectron spectroscopy (PES) on [M1Au37(PET)24]- (M = Pd and Pt), which are isoelectronic and isostructural with Au38(PET)24. To this end, the neutral precursors [M1Au37(PET)24]0 were first synthesized by fusion reactions between hydride-doped clusters [HAu9(PPh3)8]2+ and [M1Au24(PET)18]-. The formation of bi-icosahedral M1Au22 cores with open electronic structure in [M1Au37(PET)24]0 was confirmed by single-crystal X-ray diffraction analysis and electron paramagnetic resonance measurement. Then, the target anions [M1Au37(PET)24]- were obtained by reducing [M1Au37(PET)24]0 with NaBH4, and isoelectronicity with [Au38(PET)24]0 was confirmed by optical spectroscopy and density functional theory calculations. Finally, anion PES on [M1Au37(PET)24]- observed two distinctive peaks as predicted by the SVB model: one from the nearly degenerate 1Π* orbitals and the other from the nearly degenarate 1Π and 2Σ orbitals.

Oxicam-type nonsteroidal anti-inflammatory drugs enhance Agrobacterium-mediated transient transformation in plants.

Agrobacterium-mediated transformation is a key innovation for plant breeding, and routinely used in basic researches and applied biology. However, the transformation efficiency is often the limiting factor of this technique. In this study, we discovered that oxicam-type nonsteroidal anti-inflammatory drugs, including tenoxicam (TNX), increase the efficiency of Agrobacterium-mediated transient transformation. TNX treatment increased the transformation efficiency of Agrobacterium-mediated transformation of Arabidopsis thaliana mature leaves by agroinfiltration. The increase of efficiency by TNX treatment was not observed in dde2/ein2/pad4/sid2 quadruple mutant, indicating that TNX inhibits the immune system mediated by jasmonic acid, ethylene, and salicylic acid against to Agrobacterium. We also found that TNX-treatment is applicable for the transient expression and subcellular localization analysis of fluorescent-tagged proteins in Arabidopsis leaf cells. In addition, we found that TNX increases the efficiency of Agrobacterium-mediated transient transformation of Jatropha. Given that treatment with oxicam compounds is a simple and cost effective method, our findings will provide a new option to overcome limitations associated with Agrobacterium-mediated transformation of various plant species.

What is the "washout" of hepatocellular carcinoma as observed on the equilibrium phase CT?: consideration based on the concept of extracellular volume fraction.

PURPOSE: To verify the hypothesis that extracellular volume fraction (ECV) and precontrast CT density are the main determinants of washout of hepatocellular carcinoma (HCC) at the equilibrium phase CT. MATERIALS AND METHODS: Between 2018 and 2020, patients with surgically resected HCC were recruited who had undergone preoperative 4-phase CT. Those larger than 6 cm were excluded to minimize the possibility of intratumoral hemorrhage or degeneration. Two radiologists reviewed the whole images in consensus and divided cases into washout positive and negative groups. Washout positive group at the equilibrium phase was defined as "HCC showing relatively low density as compared to the surrounding background liver (BGL), irrespective of the presence of early enhancement or fibrous capsule". Several clinico-pathological and radiological features, including ECV and precontrast CT density, were correlated to the presence of washout, using uni- and multi-variable analyses. RESULTS: 27 HCC in 24 patients met the inclusion criteria. 22 (82%) and five HCC belonged to washout positive and negative groups, respectively. Univariable analysis revealed ECV of HCC and BGL, ECV difference between HCC and BGL, and presence of fibrous capsule on the equilibrium phase CT were the significant factors. Multivariable analysis showed ECV of HCC and BGL, and precontrast CT density of BGL, were the independently significant factors related to washout, suggesting washout is more likely observed with lower HCC ECV, higher BGL ECV, and higher BGL precontrast CT density. CONCLUSION: Major determinants of washout of HCC may be ECV of HCC and BGL, and precontrast CT density of BGL.

The intracellular pathogen Francisella tularensis escapes from adaptive immunity by metabolic adaptation.

Intracellular pathogens lose many metabolic genes during their evolution from free-living bacteria, but the pathogenic consequences of their altered metabolic programs on host immunity are poorly understood. Here, we show that a pathogenic strain of Francisella tularensis subsp. tularensis (FT) has five amino acid substitutions in RibD, a converting enzyme of the riboflavin synthetic pathway responsible for generating metabolites recognized by mucosal-associated invariant T (MAIT) cells. Metabolites from a free-living strain, F. tularensis subsp. novicida (FN), activated MAIT cells in a T-cell receptor (TCR)-dependent manner, whereas introduction of FT-type ribD to the free-living strain was sufficient to attenuate this activation in both human and mouse MAIT cells. Intranasal infection in mice showed that the ribD FT-expressing FN strain induced impaired Th1-type MAIT cell expansion and resulted in reduced bacterial clearance and worsened survival compared with the wild-type free-living strain FN. These results demonstrate that F. tularensis can acquire immune evasion capacity by alteration of metabolic programs during evolution.

RAB GTPases and SNAREs at the trans-Golgi network in plants.

Membrane traffic is a fundamental cellular system to exchange proteins and membrane lipids among single membrane-bound organelles or between an organelle and the plasma membrane in order to keep integrity of the endomembrane system. RAB GTPases and SNARE proteins, the key regulators of membrane traffic, are conserved broadly among eukaryotic species. However, genome-wide analyses showed that organization of RABs and SNAREs that regulate the post-Golgi transport pathways is greatly diversified in plants compared to other model eukaryotes. Furthermore, some organelles acquired unique properties in plant lineages. Like in other eukaryotic systems, the trans-Golgi network of plants coordinates secretion and vacuolar transport; however, uniquely in plants, it also acts as a platform for endocytic transport and recycling. In this review, we focus on RAB GTPases and SNAREs that function at the TGN, and summarize how these regulators perform to control different transport pathways at the plant TGN. We also highlight the current knowledge of RABs and SNAREs' role in regulation of plant development and plant responses to environmental stimuli.

A Basic Study for Predicting Dysphagia in Panoramic X-ray Images Using Artificial Intelligence (AI)-Part 1: Determining Evaluation Factors and Cutoff Levels.

BACKGROUND: Dysphagia relates to quality of life; this disorder is related to the difficulties of dental treatment. PURPOSE: To detect radiographic signs of dysphagia by using panoramic radiograph with an AI system. METHODS: Seventy-seven patients who underwent a panoramic radiograph and a videofluorographic swallowing study were analyzed. Age, gender, the number of remaining teeth, the distance between the tongue and the palate, the vertical and horizontal hyoid bone position, and the width of the tongue were analyzed. Logistic regression analysis was used. For the statistically significant factors, the cutoff level was determined. The cutoff level was determined by using analysis of the receiver operations characteristic (ROC) curve and the Youden Index. RESULTS: A significant relationship with presence of dysphagia was only observed for the vertical hyoid bone position. The area under the curve (AUC) was 0.72. The cutoff level decided for the hyoid bone was observed to be lower than the mandibular border line. CONCLUSIONS: In cases where the hyoid bone is lower than the mandibular border line on a panoramic radiograph, it suggests the risk of dysphagia would be high. We will create an AI model for the detection of the risk of dysphagia by using the assessment of vertical hyoid bone position.

Importance of extracellular volume fraction of the spleen as a predictive biomarker for high-risk esophago-gastric varices in patients with chronic liver diseases: A preliminary report.

PURPOSE: To clarify clinico-radiological factors for high-risk esophago-gastric varices (EGV), including extracellular volume fraction (ECV) of the liver, pancreas, and the spleen. METHODS: Between 2014 and 2018, 70 chronic liver disease patients who underwent 4-phase CT of the upper abdomen and either of upper gastrointestinal tract endoscopy, or actual treatment for bleeding EGV, within three months after CT, were retrospectively included. Patients were subdivided into high-risk EGV group (HRG), who had high-risk endoscopic findings or actual hemostatic treatments, and non-high-risk EGV group (NHRG). ECV of the liver, pancreas, and the spleen was measured on the ECV map generated from routine diagnostic CT data, and additional clinico-radiological factors including direct visualization of EGV on portal venous phase CT, were correlated to HRG, using both univariable and multivariable analyses. RESULTS: There were 8 and 62 patients in HRG, and NHRG, respectively. None had symptoms related to EGV at the time of CT examinations. Univariable analysis revealed splenic volume, liver and splenic ECVs, and EGV visualization on portal venous phase CT, as significant factors. Multivariable analysis suggested that EGV visualization, splenic ECV, and splenic volume were independently significant factors. Using these three factors, sensitivity/specificity/positive predictive value/negative predictive value/accuracy = 100/85/40/100/87% were obtained with partition model analysis. CONCLUSIONS: High-risk EGV can be predicted with acceptable accuracy using routine diagnostic CT data including splenic ECV.

Peptide Sequence Mapping around Bisecting GlcNAc-Bearing N-Glycans in Mouse Brain.

N-glycosylation is essential for many biological processes in mammals. A variety of N-glycan structures exist, of which, the formation of bisecting N-acetylglucosamine (GlcNAc) is catalyzed by N-acetylglucosaminyltransferase-III (GnT-III, encoded by the Mgat3 gene). We previously identified various bisecting GlcNAc-modified proteins involved in Alzheimer's disease and cancer. However, the mechanisms by which GnT-III acts on the target proteins are unknown. Here, we performed comparative glycoproteomic analyses using brain membranes of wild type (WT) and Mgat3-deficient mice. Target glycoproteins of GnT-III were enriched with E4-phytohemagglutinin (PHA) lectin, which recognizes bisecting GlcNAc, and analyzed by liquid chromatograph-mass spectrometry. We identified 32 N-glycosylation sites (Asn-Xaa-Ser/Thr, Xaa ≠ Pro) that were modified with bisecting GlcNAc. Sequence alignment of identified N-glycosylation sites that displayed bisecting GlcNAc suggested that GnT-III does not recognize a specific primary amino acid sequence. The molecular modeling of GluA1 as one of the good cell surface substrates for GnT-III in the brain, indicated that GnT-III acts on N-glycosylation sites located in a highly flexible and mobile loop of GluA1. These results suggest that the action of GnT-III is partially affected by the tertiary structure of target proteins, which can accommodate bisecting GlcNAc that generates a bulky flipped-back conformation of the modified glycans.

Cargo sorting zones in the trans-Golgi network visualized by super-resolution confocal live imaging microscopy in plants.

The trans-Golgi network (TGN) has been known as a key platform to sort and transport proteins to their final destinations in post-Golgi membrane trafficking. However, how the TGN sorts proteins with different destinies still remains elusive. Here, we examined 3D localization and 4D dynamics of TGN-localized proteins of Arabidopsis thaliana that are involved in either secretory or vacuolar trafficking from the TGN, by a multicolor high-speed and high-resolution spinning-disk confocal microscopy approach that we developed. We demonstrate that TGN-localized proteins exhibit spatially and temporally distinct distribution. VAMP721 (R-SNARE), AP (adaptor protein complex)-1, and clathrin which are involved in secretory trafficking compose an exclusive subregion, whereas VAMP727 (R-SNARE) and AP-4 involved in vacuolar trafficking compose another subregion on the same TGN. Based on these findings, we propose that the single TGN has at least two subregions, or "zones", responsible for distinct cargo sorting: the secretory-trafficking zone and the vacuolar-trafficking zone.