Characterizations of a neutralizing antibody broadly reactive to multiple gluten peptide:HLA-DQ2.5 complexes in the context of celiac disease

In human celiac disease (CeD) HLA-DQ2.5 presents gluten peptides to antigen-specific CD4+ T cells, thereby instigating immune activation and enteropathy. Targeting HLA-DQ2.5 with neutralizing antibody for treating CeD may be plausible, yet using pan-HLA-DQ antibody risks affecting systemic immunity, while targeting selected gluten peptide:HLA-DQ2.5 complex (pHLA-DQ2.5) may be insufficient. Here we generate a TCR-like, neutralizing antibody (DONQ52) that broadly recognizes more than twenty-five distinct gluten pHLA-DQ2.5 through rabbit immunization with multi-epitope gluten pHLA-DQ2.5 and multidimensional optimization. Structural analyses show that the proline-rich and glutamine-rich motif of gluten epitopes critical for pathogenesis is flexibly recognized by multiple tyrosine residues present in the antibody paratope, implicating the mechanisms for the broad reactivity. In HLA-DQ2.5 transgenic mice, DONQ52 demonstrates favorable pharmacokinetics with high subcutaneous bioavailability, and blocks immunity to gluten while not affecting systemic immunity. Our results thus provide a rationale for clinical testing of DONQ52 in CeD.

Semisolid Enteral Nutrients Alter the Pharmacokinetics of Orally Administered Levetiracetam in Rats

Enteral nutrients (ENs) affect the plasma drug concentration of orally co-administered drugs, particularly those of antiepileptic drugs, such as phenytoin and carbamazepine. However, few studies have reported the interactions of levetiracetam (LEV), an upcoming antiepileptic drug, with ENs. In this study we aimed to investigate the pharmacokinetics of LEV in 55 rats after oral co-administration of LEV with liquid or semisolid ENs. Compared with the control group, co-administration with Terumeal ® Soft significantly decreased the plasma LEV concentration at 0.5, 1, and 2 h and area under the plasma concentration-time curve from 0 to 3 h (AUC0→3h) (P < 0.01). However, the AUC0→3h of LEV remained unchanged following the administration of Terumeal ® Soft 2 h after the initial LEV administration. Moreover, co-administration with semisolid Racol® NF delayed the absorption of LEV without decreasing the AUC0→3h, whereas liquid Racol ® NF did not alter LEV pharmacokinetics. Thus, co-administration of LEV with Terumeal® Soft reduced the absorption of LEV from the gastrointestinal tract, which was prevented by administering Terumeal ® Soft 2 h after LEV administration. Semisolid Racol ® NF altered LEV pharmacokinetics without decreasing its gastrointestinal absorption. Our findings suggested that careful monitoring of the plasma LEV levels is necessary when co-administering LEV with Terumeal ® Soft, semisolid Racol ® NF, or any other semisolid ENs, to prevent the inadvertent effects of the interaction between LEV and ENs.

Heterointerface Created on Au-Cluster-Loaded Unilamellar Hydroxide Electrocatalysts as a Highly Active Site for the Oxygen Evolution Reaction

The oxygen evolution reaction (OER) is a critical element for all sorts of reactions that use water as a hydrogen source, such as hydrogen evolution and electrochemical CO₂ reduction, and novel design principles that provide highly active sites on OER electrocatalysts push the limits of their practical applications. Herein, Au-cluster loading on unilamellar exfoliated layered double hydroxide (ULDH) electrocatalysts for the OER is demonstrated to fabricate a heterointerface between Au clusters and ULDHs as an active site, which is accompanied by the oxidation state modulation of the active site and interfacial direct OO coupling ("interfacial DOOC"). The Au-cluster-loaded ULDHs exhibit excellent activities for the OER with an overpotential of 189 mV at 10 mA cm^-2 . X-ray absorption fine structure measurements reveal that charge transfer from the Au clusters to ULDHs modifies the oxidation states of trivalent metal ions, which can be active sites on the ULDHs. The present study, supported by highly sensitive spectroscopy combining reflection absorption infrared spectroscopy and modulation-excitation spectroscopy and density functional theory calculations, indicates that active sites at the interface between the Au clusters and ULDHs promote a novel OER mechanism through interfacial DOOC, thereby achieving outstanding catalytic performance.

The role of B cells and IgG in aortic dissection

Background

Aortic dissection (AD) is one of the destructive and fatal aortic diseases, for which molecular pathogenesis is largely unknown. Recent studies have highlighted the importance of inflammatory response in AD. We and others reported that B cells and immunoglobulins participate in pathogenesis of abdominal aortic aneurysm, another form of aortic destructive disease, by promoting inflammatory response. It is not known whether and how B cells participate in AD pathogenesis.

Methods and results

Immunohistochemical staining of human AD tissue revealed that B cells were clustered together with T cells, macrophages and neutrophils at the entry site of AD with medial disruption. B cell cluster was also observed at the site of medial disruption in mouse model of AD that was induced by continuous infusion of beta-aminopropionitrile and angiotensin II (BAPN+AngII). In muMT mouse, which is deficient for B cells and immunoglobulins due to genetic deletion of immunoglobulin heavy chain, BAPN+AngII induced significantly less severe AD compared to that in wild type. Depositions of IgG and fibrinogen, one of the endogenous antigen for natural IgG, were observed after BAPN+AngII infusion before and after AD development in wild type mice. Deposition of fibrinogen was also observed in mMT mice after BAPN+AngII infusion. The rate of aortic rupture and sudden death was approximately 42% in wild type mice, while that in muMT mouse was 12% (P&lt;0.05). Administration of mouse normal polyclonal IgG to muMT mice resulted in dramatic increase in aortic rupture and sudden death, starting at day 7 of BAPN+AngII infusion, and reaching 69% of rupture rate, indicating the critical role of IgG in AD.

Conclusion

These findings demonstrated B cells and IgG are critically involved in the destructive inflammation of AD pathogenesis. Further, the deposition of fibrinogen, one of the targets of natural IgG, precedes the development of AD. Our findings may provide the conceptual foundation of the diagnostic strategy for on-going tissue destruction and for the therapeutic opportunities to intervene the progressive tissue destruction in AD.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): The Japan Society for the Promotion of Science

Interaction between phenytoin and enteral nutrients and its influence on gastrointestinal absorption

The gastrointestinal absorption of phenytoin (PHT), an antiepileptic drug, is often affected by its interaction with co-administered enteral nutrients through a nasogastric (NG) tube, resulting in decreased plasma PHT concentration. In this study, we measured the recovery rate (%) of PHT (Aleviatin^® powder) passed through an NG tube when co-administered with distilled water or enteral nutrients (F2α^®, Racol^® NF, Ensure Liquid^® and Renalen^® LP). We also measured plasma PHT levels in rats, after oral co-administration of PHT with enteral nutrients. We demonstrate that PHT recovery rate was close to 100 % in all cases after passage through the NG tube. In the rat study, the AUC_0→∞ of PHT concentration after oral administration significantly decreased when it was co-administered with F2α^® and Racol^® NF compared to distilled water. However, the AUC_0→∞ of PHT was unchanged when co-administered with F2α^® 2 h after initial PHT administration. We therefore conclude that the co-administration of PHT with F2α^® and Racol^® NF caused a reduction in the absorption of PHT from the gastrointestinal tract to the blood, without adsorption to the NG tube. The administration of enteral nutrients 2 h after PHT is one clear way to prevent a decrease in plasma PHT concentration.

Risk factors increasing blood pressure in Japanese colorectal cancer patients treated with bevacizumab

Bevacizumab has been reported to increase blood pressure. However, the factors, including patient characteristics and laboratory data contributing to this side effect remain unclear. Therefore, we investigated the relationships between increased blood pressure and bevacizumab administration, patient characteristics, and laboratory data. Between April 2007 and January 2018, factor analysis was retrospectively conducted by monitoring increases in blood pressure, the status of bevacizumab administration, patient characteristics, and laboratory data before the first administration in Japanese patients with colorectal cancer who satisfied the criteria for this study. Sixty-seven patients were included, 34 of whom (50.7%) had an increase in blood pressure after bevacizumab administration. On univariate analysis, liver metastasis, antihypertensive drug use, systolic blood pressure at rest before the first bevacizumab administration, body mass index, creatinine, and blood platelet count were significantly different between the two groups. Multivariate analysis was conducted using increased blood pressure as an objective variable and the factors extracted by the univariate analysis as explanatory variables. The results suggested that liver metastasis, antihypertensive drugs, systolic blood pressure at rest before the first bevacizumab administration, and creatinine were associated with the increase in blood pressure. Furthermore, a log-rank test performed based on Kaplan-Meier curves demonstrated that liver metastasis in patients not taking antihypertensive drugs and antihypertensive drug use in patients without liver metastasis were significantly associated with increased blood pressure. Additionally, liver metastasis in patients with antihypertensive drug use was significantly associated with increased blood pressure. Our findings suggest that liver metastasis and antihypertensive drug use, which was previously reported, are risk factors for increased blood pressure.

Characterization of polymer-polymer type charge-transfer (CT) blend membranes for fuel cell application

The data presented in this article are related to polymer-polymer type charge-transfer blend membranes for fuel cell application. The visible spectra of the charge-transfer (CT) blend membranes indicated formation of CT complex in the blend membranes, and behavior of CT complex formation by polymers was clarified by Job plot of the visible spectra. The effect of fluorine for membrane property and fuel cell performance of CT blend membranes were evaluated by ¹⁹F NMR and overvoltage analysis, respectively.

Molecular species of prostaglandins involved in modulating luteinising hormone pulses of female rats under infectious stress conditions

Mammalian reproductive function is controlled by the hypothalamic-pituitary-gonadal (HPG) axis, which is suppressed under infectious stress conditions. By analysing the pulsatility of luteinising hormone (LH), we have previously demonstrated that prostaglandins (PGs) in the central nervous system mediate infectious stress to suppress the activity of the HPG axis. The present study aimed to characterise the types of PGs responsible for suppression of the HPG axis. We focused on three major types of PGs: PGE₂ , PGD₂ and PGF_2α . We used female rats overiectomised bilaterally 1 week before the experiments. Lipopolysaccharide (100 μg kg^-1 ) suppressed LH pulses at the same time as enhancing the concentration of all three PGs in the cerebrospinal fluid, which was restored by indomethacin (10 mg kg^-1 ). Subsequently, we observed LH pulsatility after a single injection of each PG and after co-injection of PGE₂ with PGF_2α into the third cerebral ventricle. A single injection of PGE₂ dose-dependently induced a transient increase in mean LH concentration and LH pulse amplitude, and PGD₂ significantly increased the amplitude of LH pulses, wereas PGF_2α did not affect LH pulsatility. On the other hand, co-injection of PGE₂ and PGF_2α induced a significant suppression of both the frequency and amplitude of LH pulses. These results suggest that PGE₂ and PGF_2α can represent two of the mediators that suppress the HPG axis in situations of infectious stress. Moreover, the results imply that there are two contradictory effects of PGE₂ on LH pulsatility: (i) enhancive when working alone and (ii) suppressive when working together with PGF_2α .

Pretreatment of Crude Pancreatic Islets with Mitomycin C (Mmc) Prolongs Islet Graft Survival in a Xenogeneic Rat-To-Mouse Model

In this study, we examined the effect of mitomycin C (MMC) treatment on graft survival and evaluated its efficacy in immunomodulation of islet graft for transplantation. Male WS rats were used as islet donors and streptozotocin-induced diabetic C57BL/6 mice as recipients. The isolated islets were treated with MMC at concentrations of 0, 0.1, 1, 3.2, 10, 32, 100, 320, and 1000 μg/mL for 30 min, and were cultured for 20 h. Then, 300–400 islets were transplanted into the renal subcapsular space of diabetic mice. Significant prolongation of graft survival was obtained when the islets were treated with MMC at a concentration of 10, 32, or 100 μg/mL (MST 23 ± 7.4, 17.5 ± 5.4, 29.6 ± 9.7 days: p < 0.003, p < 0.012, p < 0.001, respectively, vs. 12.3 ± 2.7 days for culturing alone). Islets treated with MMC at a concentration of 320 μg/mL or more failed to restore normoglycemia in the diabetic recipient mice after transplantation. Viability of islets incubated with doses up to 100 μg/mL, assessed under the confocal microscope after propidium iodide and Hoechst 33342 staining, was maintained well comparable to that of freshly isolated islets, while those treated at 320 μg/mL was significantly decreased. Thus, a therapeutic window for MMC efficacy was found at concentrations from 10 μg/mL to 100 μg/mL. This modality is simple and effective and underlying molecular mechanisms need to be determined in the future.

Development of a Method for Converting a TAK1 Type I Inhibitor into a Type II or c-Helix-Out Inhibitor by Structure-Based Drug Design (SBDD)

We have developed a method for converting a transforming growth factor-β-activated kinase 1 (TAK1) type I inhibitor into a type II or c-helix-out inhibitor by structure-based drug design (SBDD) to achieve an effective strategy for developing these different types of kinase inhibitor in parallel. TAK1 plays a key role in inflammatory and immune signaling, and is therefore considered to be an attractive molecular target for the treatment of human diseases (inflammatory disease, cancer, etc.). We have already reported novel type I TAK1 inhibitor, so we utilized its X-ray information to design a new chemical class type II and c-helix-out inhibitors. To develop the type II inhibitor, we superimposed the X-ray structure of our reported type I inhibitor onto a type II compound that inhibits multiple kinases, and used SBDD to design a new type II inhibitor. For the TAK1 c-helix-out inhibitor, we utilized the X-ray structure of a b-Raf c-helix-out inhibitor to design compounds, because TAK1 is located close to b-Raf in the Sugen kinase tree, so we considered that TAK1 would, similarly to b-Raf, form a c-helix-out conformation. The X-ray crystal structure of the inhibitors in complex with TAK1 confirmed the binding modes of the compounds we designed. This report is notable for being the first discovery of a c-helix-out inhibitor against TAK1.

Identification of a selective inhibitor of transforming growth factor β-activated kinase 1 by biosensor-based screening of focused libraries

Transforming growth factor-β activated kinase 1 (TAK1), a member of the mitogen-activated protein kinase kinase kinase family, plays an essential role in mediating signals from various pro-inflammatory cytokines and therefore may be a good target for developing anti-inflammation agents. Herein, we report our efforts to identify TAK1 inhibitors with a good selectivity profile with which to initiate medicinal chemistry. Instead of resorting to a high-throughput screening campaign, we performed biosensor-based biophysical screening for a limited number of compounds by taking advantage of existing knowledge on kinase inhibitors. Rather than focusing on one specific inhibition mode, we searched for three different types, Type I (ATP-competitive, DFG-in), Type II (DFG-out), and Type III binders (non-ATP competitive) in parallel, and succeeded in identifying candidates in all three categories efficiently and rapidly. Finally, the biosensor-based binding kinetics for the active and inactive forms of TAK1 were measured to prioritize the Type I and Type II inhibitors. The effort resulted in the identification of a new TAK1-selective Type I compound with a thienopyrimidine scaffold that served as a good starting point for medicinal chemistry.

Mechanochromic Dynamic Covalent Elastomers: Quantitative Stress Evaluation and Autonomous Recovery

Stress evaluation in polymeric materials is important in order to not only spot danger in them before serious failure, but also precisely interpret the destructive mechanism, which can improve the lifetime and durability of polymeric materials. Here, we are able to visualize stress by color changes, as well as quantitatively estimate the stress in situ, in segmented polyurethane elastomers with diarylbibenzofuranone-based dynamic covalent mechanophores. We prepared films of the segmented polyurethanes, in which the mechanophores were incorporated in the soft segments, and efficiently activated them by mechanical force. Cleavage of the mechanophores during uniaxial elongation and their recovery after the removal of the stress were quantitatively evaluated by in situ electron paramagnetic resonance measurements, accompanied by drastic color changes.

Diarylbibenzofuranone-Based Dynamic Covalent Polymer Gels Prepared via Radical Polymerization and Subsequent Polymer Reaction

Diarylbibenzofuranone (DABBF) is a dynamic covalent bonding unit, which is in equilibrium with the corresponding radicals at room temperature, and polymers with DABBF linkages show notable properties such as self-healing. The preparation routes have been strictly limited, however, and no polymer with the linkages has been synthesized via radical polymerization because of the strong antioxidant activity of DABBF. Here we present a new method to prepare DABBF-containing polymers via radical polymerization of the precursor, arylbenzofuranone (ABF), and subsequent polymer reaction, dimerization of ABF units in the linear polymers. Polymer gels cross-linked by DABBF linkages were obtained against the relatively strong antioxidant activity of ABF and showed dynamic network reorganization at room temperature.

Mechanophores with a reversible radical system and freezing-induced mechanochemistry in polymer solutions and gels

Visualization and quantitative evaluation of covalent bond scission in polymeric materials are highly important for understanding failure, fatigue, and deterioration mechanisms and improving the lifetime, durability, toughness, and reliability of the materials. The diarylbibenzofuranone-based mechanophore radical system enabled, through electron paramagnetic resonance spectroscopy, in situ quantitative evaluation of scission of the mechanophores and estimation of mechanical energy induced along polymer chains by external forces. The coagulation of polymer solutions by freezing probably generated force but did not cleave the mechanophores. On the other hand, cross-linking led to efficient propagation of the force of more than 80 kJ mol(-1) to some mechanophores, resulting their cleavage and generation of colored stable radicals. This mechanoprobe concept has the potential to elucidate other debated issues in the polymer field as well.

Main metabolic pathways of TAK-802, a novel drug candidate for voiding dysfunction, in humans: the involvement of carbonyl reduction by 11β-hydroxysteroid dehydrogenase 1

To investigate species differences in the metabolism of TAK-802, in vitro and in vivo metabolic profiles were compared between humans and animals. TAK-802 was mainly metabolized to M-I, M-II, M-III and M-IV in human and animal liver microsomes. Especially the M-IV formation in humans was greater than that in animals. Likewise, M-IV was detected to a lower extent in the plasma and excreta of animals administered with TAK-802, whereas the AUC0-48 h of M-IV was approximately five-fold higher than that of TAK-802 in human plasma. These results indicate that the in vitro metabolic profile reflects the in vivo condition. Thus, to identify the metabolic pathway of TAK-802 in humans, the responsible enzyme to form M-IV was elucidated in vitro. Since M-IV is a reductive metabolite formed in microsomes, the possibility of involvement of 11β-hydroxysteroid dehydrogenase (11β-HSD), a carbonyl reductase located in microsomes, was first investigated. Consequently, M-IV formation was confirmed by incubation with human 11β-HSD1-expressing microsomes and was concentration-dependently inhibited by glycyrrhetinic acid, an inhibitor for 11β-HSD enzymes, indicating the involvement of 11β-HSD1 in the M-IV formation. In contrast, little M-IV formation was observed using rat 11β-HSD1, suggesting species differences between humans and rats. In addition, M-II was formed via M-IV, not via M-I and the CYP identification studies revealed that both M-I formation from TAK-802 and M-II formation from M-IV were mainly catalyzed by CYP3A4. In conclusion, 11β-HSD1 and CYP3A4 are principally responsible for the metabolism of TAK-802 in humans and 11β-HSD1 may be responsible for the observed species difference.

Increased lysosomal biogenesis in activated microglia and exacerbated neuronal damage after traumatic brain injury in progranulin-deficient mice

Progranulin (PGRN) is known to play a role in the pathogenesis of neurodegenerative diseases. Recently, it has been demonstrated that patients with the homozygous mutation in the GRN gene present with neuronal ceroid lipofuscinosis, and there is growing evidence that PGRN is related to lysosomal function. In the present study, we investigated the possible role of PGRN in the lysosomes of activated microglia in the cerebral cortex after traumatic brain injury (TBI). We showed that the mouse GRN gene has two possible coordinated lysosomal expression and regulation (CLEAR) sequences that bind to transcription factor EB (TFEB), a master regulator of lysosomal genes. PGRN was colocalized with Lamp1, a lysosomal marker, and Lamp1-positive areas in GRN-deficient (KO) mice were significantly expanded compared with wild-type (WT) mice after TBI. Expression of all the lysosome-related genes examined in KO mice was significantly higher than that in WT mice. The number of activated microglia with TFEB localized to the nucleus was also significantly increased in KO as compared with WT mice. Since the TFEB translocation is regulated by the mammalian target of rapamycin complex 1 (mTORC1) activity in the lysosome, we compared ribosomal S6 kinase 1 (S6K1) phosphorylation that reflects mTORC1 activity. S6K1 phosphorylation in KO mice was significantly lower than that in WT mice. In addition, the number of nissl-positive and fluoro-jade B-positive cells around the injury was significantly decreased and increased, respectively, in KO as compared with WT mice. These results suggest that PGRN localized in the lysosome is involved in the activation of mTORC1, and its deficiency leads to increased TFEB nuclear translocation with a resultant increase in lysosomal biogenesis in activated microglia and exacerbated neuronal damage in the cerebral cortex after TBI.

Two-week cast immobilization induced chronic widespread hyperalgesia in rats

It has been postulated that physical immobilization is an essential factor in developing chronic pain after trauma or surgery in an extremity. However, the mechanisms of sustained immobilization-induced chronic pain remain poorly understood. The present study, therefore, aimed to develop a rat model for chronic post-cast pain (CPCP) and to clarify the mechanism(s) underlying CPCP. To investigate the effects of cast immobilization on pain behaviours in rats, one hindlimb was immobilized for 2 weeks with a cast and remobilization was conducted for 10 weeks. Cast immobilization induced muscle atrophy and inflammatory changes in the immobilized hindlimb that began 2 h after cast removal and continued for 1 week. Spontaneous pain-related behaviours (licking and reduction in weight bearing) in the immobilized hindlimb were observed for 2 weeks, and widespread mechanical hyperalgesia in bilateral calves, hindpaws and tail all continued for 5-10 weeks after cast removal. A sciatic nerve block with lidocaine 24 h after cast removal transitorily abolished bilateral mechanical hyperalgesia in CPCP rats, suggesting that sensory inputs originating in the immobilized hindlimb contribute to the mechanism of both ipsilateral and contralateral hyperalgesia. Intraperitoneal injection of the free radical scavengers 4-hydroxy-2,2,6,6-tetramethylpiperydine-1-oxy1 or N-acetylcysteine 24 h after cast removal clearly inhibited mechanical hyperalgesia in bilateral calves and hindpaws in CPCP rats. These results suggest that cast immobilization induces ischaemia/reperfusion injury in the hindlimb and consequent production of oxygen free radicals, which may be involved in the mechanism of widespread hyperalgesia in CPCP rats.