Effective design of PEGylated polyion complex (PIC) nanoparticles for enhancing PIC internalisation in cells utilising block copolymer combinations with mismatched ionic chain lengths

In nanomedicine, PEGylation of nanomaterials poses a dilemma since it inhibits their interaction with target cells and enables their retention in target tissues despite its biocompatibility and nonspecific internalisation suppression. PEGylated polypeptide-based polyion complexes (PICs) are fabricated via the self-assembly of PEGylated aniomers and homocatiomers based on electrostatic interactions. We propose that various parameters like block copolymer design and PIC domain characteristics can enhance the cell-PEGylated PIC interactions. Remarkably, the properties of the PIC domain were tuned by the matched/mismatched ionomer chain lengths, PIC domain crosslinking degree, chemical modification of cationic species after crosslinking, PIC morphologies (vesicles/micelles) and polyethylene glycol (PEG) chain lengths. Cellular internalisation of the prepared PICs was evaluated using HeLa cells. Consequently, mismatched ionomer chain lengths and vesicle morphology enhanced cell-PIC interactions, and the states of ion pairing, particularly cationic residues, affected the internalisation behaviours of PICs via acetylation or guanidinylation of amino groups on catiomers. This treatment attenuated the cell-PIC interactions, possibly because of reduced interaction of PICs with negatively charged species on the cell-surface, glycosaminoglycans. Moreover, morphology and PEG length were correlated with PIC internalisation, in which PICs with longer and denser PEG were internalised less effectively. Cell line dependency was tested using RAW 264.7 macrophage cells; PIC recognition could be maintained after capping amino groups on catiomers, indicating that the remaining anionic groups were still effectively recognised by the scavenger receptors of macrophages. Our strategy for tuning the physicochemical properties of the PEGylated PIC nanocarriers is promising for overcoming the PEG issue.

Oral Administration of PLGA Nanoparticles to Deliver Antisense Oligonucleotides to Inflammatory Lesions in the Gastrointestinal Tract

In this study, we prepared antisense oligonucleotide (ASO)-encapsulated nanoparticles (NPs) with a suitable profile for oral administration for the treatment of inflammatory bowel disease (IBD). We chose a water-in-oil-in-water (w/o/w) method to prepare the NPs using poly(lactide-co-glycolide) as a matrix and Pluronic as a stabilizer. The obtained NPs had a suitable diameter (158 nm) for the penetration of the mucus layer, endocytic uptake by enterocytes, and accumulation in inflammatory lesions in the intestine. The amount of ASOs in the NPs was relatively large (6.41% (w/w)). When the NPs were stably dispersed in solutions that mimicked gastrointestinal (GI) juice, minimal leakage of ASOs was demonstrated over the required period. The NPs were administered orally to mice with colitis induced by dextran sodium sulfate, which reduced target gene expression in the colons and rectums of the mice, whereas naked ASO administration caused no reduction in gene expression. Thus, the NPs have the potential of promising oral carriers of ASOs for the treatment of IBD that specifically target inflammatory lesions in the GI tract, thereby reducing the non-specific toxic effects of ASOs.

Safe and efficient oral allergy immunotherapy using one-pot-prepared mannan-coated allergen nanoparticles

Allergen immunotherapy (AIT) is the only curative treatment for allergic diseases. However, AIT has many disadvantages related to efficiency, safety, long-term duration, and patient compliance. Dendritic cells (DCs) have an important role in antigen-specific tolerance induction; thus, DC-targeting strategies to treat allergies such as glutaraldehyde crosslinked antigen to mannoprotein (MAN) have been established. However, glutaraldehyde crosslinking may reduce the antigen presentation efficiency of DCs. To overcome this, we developed a MAN-coated ovalbumin (OVA) nanoparticle (MDO), which uses intermolecular disulfide bond to crosslink OVA and MAN. MDO effectively targeted DCs resulting in tolerogenic DCs, and promoted higher antigen presentation efficiency by DCs compared with OVA or glutaraldehyde crosslinked nanoparticles. In vitro and in vivo experiments showed that DCs exposed to MDO induced Treg cells. Moreover, MDO had low reactivity with anti-OVA antibodies and did not induce anaphylaxis in allergic mice, demonstrating its high safety profile. In a mouse model of allergic asthma, MDO had significant preventative and therapeutic effects when administered orally or subcutaneously. Therefore, MDO represents a promising new approach for the efficient and safe treatment of allergies.

Development of novel tracers for sentinel node identification in cervical cancer

Indocyanine green (ICG) with near-infrared (NIR) fluorescence imaging is used for lymphatic mapping. However, binding of ICG to blood proteins like serum albumin can shorten its retention time in sentinel lymph nodes (SLNs). Here, we investigated the efficacy and safety of a new fluorescence tracer comprising phytate and liposome (LP)-encapsulated ICG. Coadministration of phytate with LP containing phosphatidic acid promotes chelation mediated by Ca2+ in bodily fluids to enhance SLN retention. Uniformly sized LPs (100 nm) encapsulating ICG under conditions that minimized fluorescence self-quenching during storage were produced. We analyzed the behavior of the new tracer (ICG-phytate-LP) and control tracers (ICG and ICG-LP) in the lymphatic flow of mice in terms of lymph node retention time. We also tested lymphatic flow and safety in pigs that have a more human-like lymphatic system. LPs encapsulating stabilized ICG were successfully prepared. Mixing LP with phytate in the presence of Ca2+ increased both the particle size and negative surface charge. In mice, ICG-phytate-LP had the best lymph node retention, with a fluorescence intensity ratio that increased over 6 h and then decreased slowly over the next 24 h. In pigs, administration of ICG and ICG-phytate-LP resulted in no death or weight loss. There were no obvious differences between blood test results for the ICG and ICG-phytate-LP groups, and the overall safety was good. ICG-phytate-LP may be a useful new tracer for gynecological cancers that require time for lymph node identification due to a retroperitoneal approach.

First GC/MS identification of aqueous ammonia: utilization of ethenesulfonyl fluoride as a selective and rapid derivatization reagent of ammonia in aqueous media

Identification as well as quantification of ammonia are required in some analytical fields including forensic science. For this purpose, gas chromatography/mass spectrometry (GC/MS) analysis is one of the most suitable techniques. Although ammonia needs to be derivatized for GC/MS analysis, conventional derivatization reagents require anhydrous conditions because they are highly reactive with water. Here, we investigated ethenesulfonyl fluoride (ESF) as a selective reagent for ammonia derivatization in aqueous media to develop a rapid identification method for ammonia in aqueous media. The Michael addition reaction of ammonia with ESF rapidly produced a tri-ESF derivative suitable for GC/MS analysis. We optimized the derivatization reaction conditions and extraction solvent. With the optimized protocol, the detection limit for aqueous ammonia was 0.05 μg mL-1. The calibration curve showed good linearity (R2 = 0.9998) in the range of 0.10-100.0 μg mL-1, and the accuracy (% bias) and the precision (% relative standard deviation) for concentrations of 0.10, 0.25, 10.0, and 75.0 μg mL-1 were within ± 10% (intra- and inter-day). The proposed ESF-based method could quantify ammonia in samples containing interfering nucleophilic substances. This method was successfully applied to ammonia-containing commercial products.

Measurements of neutrino oscillation parameters from the T2K experiment using 3.6×1021 protons on target

The T2K experiment presents new measurements of neutrino oscillation parameters using 19.7 ( 16.3 ) × 10 20 protons on target (POT) in (anti-)neutrino mode at the far detector (FD). Compared to the previous analysis, an additional 4.7 × 10 20 POT neutrino data was collected at the FD. Significant improvements were made to the analysis methodology, with the near-detector analysis introducing new selections and using more than double the data. Additionally, this is the first T2K oscillation analysis to use NA61/SHINE data on a replica of the T2K target to tune the neutrino flux model, and the neutrino interaction model was improved to include new nuclear effects and calculations. Frequentist and Bayesian analyses are presented, including results on sin 2 θ 13 and the impact of priors on the δ CP measurement. Both analyses prefer the normal mass ordering and upper octant of sin 2 θ 23 with a nearly maximally CP-violating phase. Assuming the normal ordering and using the constraint on sin 2 θ 13 from reactors, sin 2 θ 23 = 0 . 561 - 0.032 + 0.021 using Feldman-Cousins corrected intervals, and Δ m 32 2 = 2 . 494 - 0.058 + 0.041 × 10 - 3 eV 2 using constant Δ χ 2 intervals. The CP-violating phase is constrained to δ CP = - 1 . 97 - 0.70 + 0.97 using Feldman-Cousins corrected intervals, and δ CP = 0 , π is excluded at more than 90% confidence level. A Jarlskog invariant of zero is excluded at more than 2 σ credible level using a flat prior in δ CP , and just below 2 σ using a flat prior in sin δ CP . When the external constraint on sin 2 θ 13 is removed, sin 2 θ 13 = 28 . 0 - 6.5 + 2.8 × 10 - 3 , in agreement with measurements from reactor experiments. These results are consistent with previous T2K analyses.

One-pot preparation of mannan-coated antigen nanoparticles using human serum albumin as a matrix for tolerance induction

Nanoparticles (NPs) for allergen immunotherapy have garnered attention for their high efficiency and safety compared with naked antigen proteins. In this work, we present mannan-coated protein NPs, incorporating antigen proteins for antigen-specific tolerance induction. The heat-induced formation of protein NPs is a one-pot preparation method and can be applied to various proteins. Here, the NPs were formed spontaneously via heat denaturation of three component proteins: an antigen protein, human serum albumin (HSA) as a matrix protein, and mannoprotein (MAN) as a targeting ligand for dendritic cells (DCs). HSA is non-immunogenic, therefore suitable as a matrix protein, while MAN coats the surface of the NP. We applied this method to various antigen proteins and found that the self-disperse after heat denaturation was a requirement for incorporation into the NPs. We also established that the NPs could target DCs, and the incorporation of rapamycin into the NPs enhanced the induction of a tolerogenic phenotype of DC. The MAN coating provided steric hindrance and heat denaturation destroyed recognition structures, successfully preventing anti-antigen antibody binding, indicating the NPs may avoid anaphylaxis induction. The MAN-coated NPs proposed here, prepared by a simple method, have the potential for effective and safe allergies treatment for various antigens.

Dynamic frustrated charge hotspots created by charge density modulation sequester globular proteins into complex coacervates

This study presents a simple strategy for the sequestration of globular proteins as clients into synthetic polypeptide-based complex coacervates as a scaffold, thereby recapitulating the scaffold-client interaction found in biological condensates. Considering the low net charges of scaffold proteins participating in biological condensates, the linear charge density (σ) on the polyanion, polyethylene glycol-b-poly(aspartic acids), was reduced by introducing hydroxypropyl or butyl moieties as a charge-neutral pendant group. Complex coacervate prepared from the series of reduced-σ polyanions and the polycation, homo-poly-l-lysine, could act as a scaffold that sequestered various globular proteins with high encapsulation efficiency (>80%), which sometimes involved further agglomerations in the coacervates. The sequestration of proteins was basically driven by electrostatic interaction, and therefore depended on the ionic strength and charges of the proteins. However, based on the results of polymer partitioning in the coacervate in the presence or absence of proteins, charge ratios between cationic and anionic polymers were maintained at the charge ratio of unity. Therefore, the origin of the electrostatic interaction with proteins is considered to be dynamic frustrated charges in the complex coacervates created by non-neutralized charges on polymer chains. Furthermore, fluorescence recovery after photobleaching (FRAP) measurements showed that the interaction of side-chains and proteins changed the dynamic property of coacervates. It also suggested that the physical properties of the condensate are tunable before and after the sequestration of globular proteins. The present rational design approach of the scaffold-client interaction is helpful for basic life-science research and the applied frontier of artificial organelles.

Correction: The role of ion solvation in lithium mediated nitrogen reduction

[This corrects the article DOI: 10.1039/D2TA07686A.].

The role of ion solvation in lithium mediated nitrogen reduction

Since its verification in 2019, there have been numerous high-profile papers reporting improved efficiency of lithium-mediated electrochemical nitrogen reduction to make ammonia. However, the literature lacks any coherent investigation systematically linking bulk electrolyte properties to electrochemical performance and Solid Electrolyte Interphase (SEI) properties. In this study, we discover that the salt concentration has a remarkable effect on electrolyte stability: at concentrations of 0.6 M LiClO₄ and above the electrode potential is stable for at least 12 hours at an applied current density of -2 mA cm^-2 at ambient temperature and pressure. Conversely, at the lower concentrations explored in prior studies, the potential required to maintain a given N₂ reduction current increased by 8 V within a period of 1 hour under the same conditions. The behaviour is linked more coordination of the salt anion and cation with increasing salt concentration in the electrolyte observed via Raman spectroscopy. Time of flight secondary ion mass spectrometry and X-ray photoelectron spectroscopy reveal a more inorganic, and therefore more stable, SEI layer is formed with increasing salt concentration. A drop in faradaic efficiency for nitrogen reduction is seen at concentrations higher than 0.6 M LiClO₄, which is attributed to a combination of a decrease in nitrogen solubility and diffusivity as well as increased SEI conductivity as measured by electrochemical impedance spectroscopy.

Engineered macrophages acting as a trigger to induce inflammation only in tumor tissues based on arginase 1-responsive TNF-α accelerated release

Herein, we report engineered macrophages, termed "MacTrigger," acting as a trigger to induce an inflammatory environment only in tumor tissues. This led to intensive anti-tumor effects based on the removal potential of foreign substances. The strength of this study is the utilization of two unique functions of macrophages: (1) their ability to migrate to tumor tissues and (2) polarization into the anti-inflammatory M2 phenotype in the presence of tumor tissues. The MacTrigger accelerated the release of inflammatory cytokines, tumor necrosis factor-alpha (TNF-α), when it was polarized to the M2 phenotype. When the MacTrigger was administered to tumor-bearing mice, tumor growth was significantly inhibited compared with the non-treatment group, the un-transfected macrophages group, and the group with engineered macrophages capable of randomly releasing TNF-α. Additionally, the ratio of the M1 phenotype to the M2 phenotype in tumor tissues was >1 only in the MacTrigger group. Moreover, the ratios of natural killer cells and CD8⁺T cells in tumor tissues were increased compared with other groups. These results indicate that MacTrigger can induce inflammation in tumor tissues, leading to effective anti-tumor effects. In normal tissues, especially the liver, notable side effects were not observed. This is because, in the liver, the MacTrigger was not polarized to the M2 phenotype and could not induce inflammation. These results suggest that the MacTrigger is a "trigger" that can induce inflammation only in tumor tissues, then allowing the body to attack tumor tissues through the innate immunity system.

Characterization of polypropyleneimine as an alternative transfection reagent

Polypropyleneimine (PPI) was examined as a transfection reagent comparing with most widely used polymer, polyethyleneimine (PEI). PPI had better responsiveness to the endosomal pH and showed more condensation ability of plasmid DNA than PEI. Although the cytotoxicity of PPI was somewhat higher than PEI, the transfection efficacy of PPI was comparable with PEI or higher than PEI in some cell line. Thus, PPI would be an alternative transfection reagent.

Facile preparation of hexagonal nanosheets via polyion complex formation from α-helical polypeptides and polyphosphate-based molecules

The polyion complex-based supramolecular self-assembly of hexagonal nanosheets was achieved via the complexation of a PEGylated block catiomer with ATP and other polyphosphate-containing small molecules. The formation of hexagonal nanosheets required the presence of a polyethylene glycol block and α-helix formation in the catiomer block, which was induced by complexation with the polyphosphate moiety.

A human cell orthogonal enzyme β-D-galacturonidase for sensitive detection of antigen proteins

Enzymes are used to amplify signals for detection of antigen proteins in biological samples. However, the enzymes conventionally used for this purpose have limitations, such as the presence of the...

Quiescent B Cells Acquire Sensitivity to Cell Cycle Arresting Agents by B Cell Receptor Stimulation

For the treatment of autoimmune diseases, depletion of B cells specific for auto-antigens is important because they will be a source of plasmablasts/plasma cells to produce autoantibodies. However, because some types of B cells like naïve B cells and memory B cells are at quiescent phase, they are insensitive to anticancer drugs which exert cytotoxicity by arresting the cell cycle. Here we show that B cell receptor (BCR) stimulation increases the sensitivity of anticancer drugs by promoting the proliferation of quiescent B cells. The BCR stimulation to primary naïve B cells enhanced sensitivity to several anticancer drugs which arrest the cell cycle through different mechanisms. The present results indicated that combination of the BCR stimulation and anticancer drugs is a promising strategy for the antigen-specific depletion of pathogenic quiescent B cells.

Nanostructure Control of an Antibiotic-based Polyion Complex Using a Series of Polycations with Different Side-chain Modification Rates

Developing nanovehicles for delivering antibiotics is a promising approach to overcome the issue of antibiotic resistance. This study aims to utilize a polyion complex (PICs) system for developing novel nanovehicles for polymyxin-type antibiotics, which are known as last resort drugs. The formation of antibiotic-based PIC nanostructures was investigated using colistimethate sodium (CMS), an anionic cyclic short peptide, and a series of block catiomers bearing different amounts of guanidinium moieties on their side chains. In addition, only the modified catiomer, and not the unmodified catiomer, self-assembles with CMS, implying the importance of the guanidine moieties for enhancing the interaction between the catiomer and CMS via the formation of multivalent hydrogen bonding. Moreover, micellar and vesicular PIC nanostructures are selectively formed depending on the ratio of the guanidine residues. Size-exclusion chromatography revealed that the encapsulation efficiency of CMS is dependent on the guanidinium modification ratio. The antimicrobial activity of the PIC nanostructures is also confirmed, indicating that the complexation of CMS in the PICs and further release from the PICs successfully occurs. This article is protected by copyright. All rights reserved.

POS0728 ASSOCIATION BETWEEN TREATMENT GOAL ACHIEVEMENT AND GRIT PERSONALITY CHARACTERISTICS OF ATTENDING PHYSICIAN IN PATIENTS WITH SYSTEMIC LUPUS ERYTHEMATOSUS: A MULTICENTER CROSS-SECTIONAL STUDY

Background

In clinical practice for systemic lupus erythematosus (SLE), the concept of “treat to target” has been introduced with an established goal of reducing glucocorticoid dose as much as possible while controlling disease activity. Although it has been shown that various personality characteristics of patients with SLE affect their disease activity and damage, it is not clear whether the personality characteristics of attending physicians affect the outcomes of patients with SLE. Grit is a personality trait characterized by perseverance and passion for achieving long-term goals.

Objectives

This study aims to evaluate the relationship between attending physicians’ grit personality characteristics and treatment goal achievements in patients with SLE.

Methods

A cross-sectional study was conducted on 386 patients with SLE in five referral hospitals in Japan. The main exposure was the “perseverance” and “consistency” (scores 1-5) of the attending physicians, as measured by the Short Grit Scale, and the primary outcome was the achievement of the Lupus Low Disease Activity Score (LLDAS). Considering the clustering of achievement of LLDAS by each attending physician, the association between attending physician’s personality and LLDAS was analyzed by logistic regression with cluster robust variance estimation. Odds ratios to assess the relationship between perseverance and consistency and LLDAS were estimated with adjustment for confounders (age, sex, disease duration, hydroxychloroquine use, immunosuppressant use, and Systemic Lupus International Collaborating Clinics-Damage Index). We used multiple imputation to handle the uncertainty caused by missing values of potential confounders on the assumption of missing at random.

Results

The median age of the patients was 45 years (interquartile range[IQR],36-56), 88% were female, and the median disease duration was 152 months(IQR, 80-240). Thirty-seven doctors were in charge of the patients (1-79 patients/each doctor). The median age of the attending physicians was 40 years (IQR, 35-43), and 19% were female. The median perseverance and consistency scores of attending physicians were 3.1 (IQR, 3.0-3.5) and 3.3 (IQR, 2.8-3.8), respectively. Of the enrolled patients, 154 (40%) had achieved LLDAS. The attending physicians with a lower consistency score of <3 were more frequent in the patients who achieved LLDAS (40% vs. 29%, p=0.026). The lower consistency score of attending physicians was still related to LLDAS independently (adjusted odds ratio 1.63, 95% confidential interval 1.17-2.27). There was no association between the achievement of LLDAS and perseverance.

Conclusion

The grit personality characteristics of the attending physician may affect the achievement of treatment goals in patients with SLE.

Disclosure of Interests

KEN-EI SADA Speakers bureau: I received speaker’s fees from Glaxo Smith Kline K.K., Grant/research support from: I received a research grant from Pfizer Inc., Yoshia Miyawaki: None declared, Kenta Shidahara: None declared, Shoichi Nawachi: None declared, Yu Katayama: None declared, Yosuke ASANO: None declared, Keigo Hayashi: None declared, Keiji Ohashi: None declared, Eri Katsuyama: None declared, Takayuki Katsuyama: None declared, Mariko Narazaki: None declared, Yoshinori Matsumoto: None declared, Nao Oguro: None declared, Yuichi Ishikawa: None declared, Natsuki Sakurai: None declared, Chiharu Hidekawa: None declared, Ryusuke Yoshimi: None declared, Takanori Ichikawa: None declared, Dai Kishida: None declared, Yasuhiro Shimojima: None declared, Noriaki Kurita: None declared, Nobuyuki Yajima: None declared

POS1475-HPR THE MINIMALLY IMPORTANT DIFFERENCE AS THE INTERPRETABILITY OF EMOTIONAL HEALTH DOMAIN IN JAPANESE VERSION OF LupusPRO FOR SLE PATIENTS; PRELIMINARY RESULTS OF A PROSPECTIVE COHORT STUDY

Background

The minimally important difference (MID) required to interpret the magnitude of changes in lupus patient-reported outcome (LupusPRO), which is a widely used outcome measure of quality of life in SLE patients, remains unclear.

Objectives

We report preliminary results of an ongoing prospective observational study that assesses the MID as the interpretability of emotional health (EH) domain in Japanese version of LupusPRO.

Methods

We recruited subjects at three university hospitals in Japan participating in an ongoing multidisciplinary cohort study (the Lupus registry of Nationwide institutions (LUNA). Of a total of 210 SLE patients enrolled during the 17-month recruitment period, patients with low disease activity, defined as SLE Disease Activity Index 2000 (SLEDAI-2K) ≤ 4, and who were seen at least twice of three months’ duration and responded to both the LupusPRO and health status change questions were included in this subcohort. The second questionnaire was given an allowance period of 30 days before or after the ​three months from starting date. Descriptive statistics were presented as means and standard deviations (SD) or counts and percentages (%). The emotional health score ranges from 0 to 100; a higher score indicates less frequent presence of symptoms. The change in health status was assessed using the 7-point Global Rating of Change 1), and the score = 0 and the score ≥ +1 were considered in the ‘unchanged’ and the minimal ‘improved’ category, respectively. MID was mainly estimated using the mean change of the groups with the score ≥ +1 as the anchor-based method, and the area under the curve (AUC) was also calculated as a sensitivity analysis to estimate MID thresholds 2) and 95% confidence intervals (CI) were constructed using 1000 bootstrapping.

Results

The mean age of the 24 eligible patients was 48 (SD 14), and 88% were female. The glucocorticoid dose, SLEDAI-2K, and Systemic Lupus International Collaborating Clinics /American College of Rheumatology Damage Index were 3.4 (2.1) mg, 1.0 (1.1) and 1.1 (1.9), respectively. The mean EH score was 67.5 (30.3), five patients (21%) had the maximum EH score at baseline, 73.4 (25.0) after three months, 7.2 (18.0) for the change in EH. The correlation coefficient and the AUC for the change in health status and the EH were 0.23 and 0.60. The mean changes were 4.1 (18.4) of the groups with ‘unchanged’ health status and 12.3 (17.1) of the groups with ‘improved’ health status. The MID for improvement was estimated at 12.3 using the anchor-based method, and the cutoff point corresponded to 9.3 [95%CI -6.7 to 25.3]) of the EH change score by the receiver operating curve method.

Conclusion

In this study, the MID (3 months) for the EH domain in the Japanese version of LupusPRO was estimated to be between 9 and 12, which was similar to the results of the previous cross-sectional study 3). The challenge in estimating the MID in our setting was the low correlation with external anchors, even though the study population was limited to patients with low disease activity, because disease activity at baseline can generally influence ‘improved’ health status.

References

[1]Kamper SJ, Maher CG, Mackay G. Global rating of change scales: a review of strengths and weaknesses and considerations for design. J Man Manip Ther. 2009;17(3):163.

[2]Froud R, Abel G. Using ROC curves to choose minimally important change thresholds when sensitivity and specificity are valued equally: the forgotten lesson of pythagoras. theoretical considerations and an example application of change in health status. PLoS One. 2014;9(12):e114468.

[3]Miyawaki Y, Shimizu S, Ogawa Y, et al. Association of glucocorticoid doses and emotional health in lupus low disease activity state (LLDAS): a cross-sectional study. Arthritis Res Ther. 2021;23(1):79.

Acknowledgements

The authors thank Yuka Nakanou for her significant assistance in data management and Kikuko Miyazaki for her expert assistance on this topic.

Disclosure of Interests

Yoshia Miyawaki: None declared, Kenta Shidahara: None declared, Shoichi Nawachi: None declared, Yosuke ASANO: None declared, Yu Katayama: None declared, Keiji Ohashi: None declared, Eri Katsuyama: None declared, Takayuki Katsuyama: None declared, Mariko Narazaki: None declared, Yoshinori Matsumoto Speakers bureau: I received speaker’s fees from Glaxo Smith Kline K.K., KEN-EI SADA Speakers bureau: I received speaker’s fees from Glaxo Smith Kline K.K., Ryo Yanai: None declared, Nobuyuki Yajima: None declared, Ayuko Takatani: None declared, Kunihiro Ichinose: None declared, Jun Wada Speakers bureau: Jun Wada receives speaker honoraria from Astra Zeneca, Daiichi Sankyo, Novartis, Novo Nordisk Pharma, Tanabe Mitsubishi and receives grant support from Astellas, Baxter, Bayer, Chugai, Dainippon Sumitomo, Kyowa Kirin, Novo Nordisk Pharma, Ono, Otsuka, Tanabe Mitsubishi, and Teijin.

Specific adsorption of a β-lactam antibiotic in vivo by an anion-exchange resin for protection of the intestinal microbiota

The fraction of antibiotics that are excreted from the intestine during administration leads to disruption of commensal bacteria as well as resulting in dysbiosis and various diseases. To protect the gut microbiota during treatment with antibiotics, use of activated carbon (AC) has recently been reported as a method to adsorb antibiotics. However, the antibiotic adsorption by AC is nonspecific and may also result in the adsorption of essential biological molecules. In this work, we reported that an anion exchange resin (AER) has better specificity than AC for adsorbing the β-lactam antibiotic cefoperazone (CEF). Because CEF has a negatively charged carboxylate group and a conjugated system, the AER was used to adsorb CEF through electrostatic and π-π interactions. The AER was specific for CEF over biological molecules such as bile acids and vitamins in the intestine. The AER protected Escherichia coli from CEF in vitro. Furthermore, oral administration of the AER reduced the fecal free CEF concentration, and protected the gut microbiota from CEF-induced dysbiosis.

A FRET-based Protein Kinase Assay Using Phos-tag-modified Quantum Dots and Fluorophore-labeled Peptides

We have developed a novel FRET-based assay to monitor protein kinase activity using quantum dots (QDs) and fluorophore-labeled substrate peptides. To develop a FRET-based protein kinase assay, it is important to consider the phosphate group recognition strategy and to ensure that the FRET pairs are close enough because the FRET efficiency is highly dependent on the distance between the FRET pairs. Here, we incorporated a phos-tag, which captures phosphate groups strongly and selectively, into a protein kinase assay to recognize phosphorylation. Our detection system was composed of phos-tag-modified QDs and Cy5-labeled substrate peptides. Because the phos-tags capture phosphate groups by forming dinuclear complexes, the Cy5-labeled substrate peptides are captured by the phos-tags on the QD surface upon protein kinase-mediated phosphorylation, which induces FRET from the QDs to Cy5 because of the approximation of Cy5 to the QDs. On the basis of the difference of this FRET efficiency, we successfully measured protein kinase A activity, which demonstrated the feasibility of our assay.

Diagnostic Accuracy of Diastolic Fractional Flow Reserve for Functional Evaluation of Coronary Stenosis

Background

In the resting conditions, narrowing the window of coronary pressure measurements from the whole cardiac cycle to diastole improves diagnostic performance of coronary pressure–derived physiological index. However, whether this also applies to the hyperemic conditions has not yet been thoroughly evaluated.

Objectives

The purpose of this study was to assess whether diastolic fractional flow reserve (diastolic FFR) has better diagnostic performance in identifying ischemia-causing coronary lesions than conventional FFR in a prospective, multicenter, and independent core laboratory–based environment.

Methods

In this prospective multicenter registry at 29 Japanese centers, we compared the diagnostic performance of FFR, diastolic FFR, resting distal to aortic coronary pressure (Pd/Pa), and diastolic pressure ratio (dPR) using myocardial perfusion scintigraphy (MPS) as the reference standard in 378 patients with single-vessel coronary disease.

Results

Inducible myocardial ischemia was found on MPS in the relevant myocardial territory of the target vessel in 85 patients (22%). In the receiver-operating curve analyses, diastolic FFR had comparable area under the curve (AUC) compared with FFR (AUC_{diastolic FFR}: 0.66; 95% confidence interval [CI]: 0.58-0.73, vs AUC_FFR: 0.66; 95% CI: 0.58-0.74, P = 0.624). FFR and diastolic FFR showed significantly larger AUCs than resting Pd/Pa (0.62; 95% CI: 0.54-0.70; P = 0.033 and P = 0.046) but did not show significantly larger AUCs than dPR (0.62; 95% CI: 0.55-0.70; P = 0.102 and P = 0.113).

Conclusions

Diastolic FFR showed a similar diagnostic performance to FFR as compared with MPS. This result reaffirms the use of FFR as the most accurate invasive physiological lesion assessment. (Diagnostic accuracy of diastolic fractional flow reserve (d-FFR) for functional evaluation of coronary stenosis; UMIN000015906)

Effect of an Endothelin B Receptor Agonist on the Tumor Accumulation of Nanocarriers

Enhancing blood flow to tumors is a prominent strategy for improving the tumor accumulation of macromolecular drugs through the enhanced permeability and retention (EPR) effect. IRL-1620 is an agonist of the endothelin B receptor, and is a promising molecule to enhance tumor blood flow by activating endothelial nitric oxide synthase. However, contradictory effects on tumor blood flow modulation have been reported because the effects of IRL-1620 may differ in different animal models. Here, we examined for the first time the effect of IRL-1620 on the EPR effect for PEGylated liposomes in a CT-26 murine colon cancer model. Co-injection of IRL-1620 at an optimum dose (3 nmol/kg) nearly doubled the tumor accumulation of liposomes compared with controls, indicating that IRL-1620 enhanced the EPR effect in the present colon cancer model. Co-injection of IRL-1620 is a promising strategy to improve the therapeutic effects of macromolecular drugs while reducing their side effects.

A Lipid-Based Nanocarrier Containing Active Vitamin D3 Ameliorates NASH in Mice via Direct and Intestine-Mediated Effects on Liver Inflammation

The gut-liver axis may be involved in non-alcoholic steatohepatitis (NASH) progression. Pathogen-associated molecular patterns leak through the intestinal barrier to the liver via the portal vein to contribute to NASH development. Active vitamin D₃ (1,25(OH)₂D₃) is a potential therapeutic agent to enhance the intestinal barrier. Active vitamin D₃ also suppresses inflammation and fibrosis in the liver. However, the adverse effects of active vitamin D₃ such as hypercalcemia limit its clinical use. We created a nano-structured lipid carrier (NLC) containing active vitamin D₃ to deliver active vitamin D₃ to the intestine and liver to elicit NASH treatment. We found a suppressive effect of the NLC on the lipopolysaccharide-induced increase in permeability of an epithelial layer in vitro. Using mice in which NASH was induced by a methionine and choline-deficient diet, we discovered that oral application of the NLC ameliorated the permeability increase in the intestinal barrier and attenuated steatosis, inflammation and fibrosis in liver at a safe dose of active vitamin D₃ at which the free form of active vitamin D₃ did not show a therapeutic effect. These data suggest that the NLC is a novel therapeutic agent for NASH.

Comparative Evaluation of Natural Killer Cell-Mediated Cell Killing Assay Based on the Leakage of an Endogenous Enzyme or a Pre-Loaded Fluorophore

A cell-killing ability of natural killer (NK) cells has been evaluated by the leakage of marker molecules from target cells. Lactate dehydrogenase (LDH) and calcein are two major non-radioisotope markers used for the killing assay. The spontaneous death of NK cells during the killing-assay of cells is a major issue in the assay because it provides background signals to increase errors. In this study, the effect of the spontaneous death of NK cells on the killing assays based on LDH and the calcein method was comparatively evaluated. We found that the calcein method is much less sensitive to the spontaneous death of NK cells to enable an accurate evaluation of the cell killing.

Effect of Size and Loading of Retinoic Acid in Polyvinyl Butyrate Nanoparticles on Amelioration of Colitis

Butyrate has been used in the treatment of inflammatory bowel diseases (IBD). However, the controlled release of butyrate has been indicated to be necessary in order to avoid the side effects verified at high concentrations. We previously developed nanoparticles (NPs) of polyvinyl butyrate (PVBu) as an oral butyrate donor for the controlled release of butyrate for the treatment of colitis. To examine the effect of the size of NPs on the therapeutic effect of colitis, here we prepared PVBu NPs with different sizes (100 nm and 200 nm). Both sizes of PVBu NPs significantly suppressed the inflammatory response in macrophages in vitro. PVBu NPs with 200 nm showed better effects on the amelioration of colitis compared with the 100 nm-NPs. We found unexpectedly that 200 nm-NP incorporated with all-trans retinoic acid (ATRA) showed a much better therapeutic effect than those with unloaded 200 nm-NPs, although ATRA alone was reported to worsen the inflammation. The synergistic effect of ATRA with butyrate shows evidence of being a promising approach for IBD treatment.

Protein Kinase C α-Responsive Gene Carrier for Cancer-Specific Transgene Expression and Cancer Therapy

The presence of intracellular signal transduction and its abnormal activities in many cancers has potential for medical and pharmaceutical applications. We recently developed a protein kinase C α (PKCα)-responsive gene carrier for cancer-specific gene delivery. Here, we demonstrate an in-depth analysis of cellular signal-responsive gene carrier and the impact of its selective transgene expression in response to malfunctioning intracellular signaling in cancer cells. We prepared a novel gene carrier consisting of a linear polyethylenimine (LPEI) main chain grafted to a cationic PKCα-specific substrate (FKKQGSFAKKK-NH₂). The LPEI-peptide conjugate formed a nanosized polyplex with pDNA and mediated efficient cellular uptake and endosomal escape. This polyplex also led to successful transgene expression which responded to the target PKCα in various cancer cells and exhibited a 10-100-fold higher efficiency compared to the control group. In xenograft tumor models, the LPEI-peptide conjugate promoted transgene expression showing a clear-cut response to PKCα. Furthermore, when a plasmid containing a therapeutic gene, human caspase-8 (pcDNA-hcasp8), was used, the LPEI-peptide conjugate had significant cancer-suppressive effects and extended animal survival. Collectively, these results reveal that our method has great potential for cancer-specific gene delivery and therapy.

Effect of a Chloroacetyl Modification on the Suppression of Dissociation of a Fluorescent Molecule from Cells for Antigen-Specific Cell Staining

We previously developed a hydrolase-based fluorescence amplification method for antigen-specific cell labelling, in which fluorescent substrates stained cells by a non-covalent hydrophobic interaction. To improve the substrates retention in cells, we examined the effect of a chloroacetyl group modification on the substrate retention. We found that the chloroacetyl group suppressed the dissociation of the substrate after forming a covalent bond with intracellular proteins. However, the slow reaction speed of the chloroacetyl group allowed dissociation for cells in the early stage of the staining reaction.

Synthesis and biological evaluation of a monocyclic Fc-binding antibody-recruiting molecule for cancer immunotherapy

Antibody-recruiting molecules (ARMs) are bispecific molecules composed of an antibody-binding motif and a target-binding motif that redirect endogenous antibodies to target cells to elicit immune responses. To enhance the translational potential of ARMs, it is crucial to design antibody/target-binding motifs that have strong affinity and are easy to synthesize. Here, we synthesized a novel Fc-binding ARM (Fc-ARM) that targets folate receptor (FR)-positive cancer cells, Reo-3, using a recently developed monocyclic peptide 15-Lys8Leu, which binds strongly to the Fc region of an antibody. Reo-3 bound to the Fc region of the antibody with a K d of 5.8 nM, and recruited a clinically used antibody mixture to attack FR-positive IGROV-1 cells as efficiently as Fc-ARM2, in which a bicyclic Fc-binding peptide was used. These results indicate that 15-Lys8Leu, which can be synthesized readily, is suitable for various applications including the development of Fc-ARMs.

Preparation of a PEGylated liposome that co-encapsulates l-arginine and doxorubicin to achieve a synergistic anticancer effect

Strategies that combine chemotherapies with unconventional agents such as nitric oxide (NO) have been shown to enhance cancer therapies. Compared with small molecule chemotherapy drugs, nanosized particles have improved therapeutic efficacies and reduced systemic side effects because of the enhanced permeability and retention effect. In this report, we prepared PEGylated liposomes (LP) that incorporated l-arginine (Arg) and the anticancer drug doxorubicin (Dox) to yield a co-delivery system (Dox–Arg-LP). On the basis of our previous research, we hypothesized that Dox–Arg-LP should achieve a synergistic anticancer effect because Arg conversion to NO by activated M1 macrophages augments the chemotherapeutic activity of Dox. Dox–Arg-LP showed comparable physical properties to those of conventional Dox-only liposomes (Dox-LP). In vitro assessment revealed that the cytotoxicity of Dox–Arg-LP toward cancer cells was significantly higher than that of Dox-LP. In vivo application of Dox–Arg-LP in mice enhanced the chemotherapeutic effect with a 2 mg kg⁻¹ dose of Dox–Arg-LP achieving the same therapeutic efficacy as a two-fold higher dose of Dox-LP (i.e., 4 mg kg⁻¹). Therefore, co-encapsulation of dual agents into a liposome formulation is an efficient strategy to enhance chemotherapy while reducing systemic toxicity.

Strategies that combine chemotherapies with unconventional agents such as nitric oxide (NO) have been shown to enhance cancer therapies.

Ligand Design for Specific MHC Class I Molecules on the Cell Surface

We have validated that ligand peptides designed from antigen peptides could be used for targeting specific major histocompatibility complex class I (MHC-I) molecules on the cell surface. To design the ligand peptides, we used reported antigen peptides for each MHC-I molecule with high binding affinity. From the crystal structure of the peptide/MHC-I complexes, we determined a modifiable residue in the antigen peptides and replaced this residue with a lysine with an ε-amine group modified with functional molecules. The designed ligand peptides successfully bound to cells expressing the corresponding MHC-I molecules via exchange of peptides bound to MHC-I. We demonstrated that the peptide ligands could be used to transport a protein or a liposome to cells expressing the corresponding MHC-I. This strategy may be useful for targeted delivery to cells overexpressing MHC-I, which have been observed in autoimmune diseases.

Fc-Binding Antibody-Recruiting Molecules Targeting Prostate-Specific Membrane Antigen: Defucosylation of Antibody for Efficacy Improvement*

Synthetic small molecules that redirect endogenous antibodies to target cells are promising drug candidates because they overcome the potential shortcomings of therapeutic antibodies, such as immunogenicity and the need for intravenous delivery. Previously, we reported a novel class of bispecific molecules targeting the antibody Fc region and folate receptor, named Fc-binding antibody-recruiting molecules (Fc-ARMs). Fc-ARMs can theoretically recruit most endogenous antibodies, inducing antibody-dependent cell-mediated cytotoxicity (ADCC) to eliminate cancer cells. Herein, we describe new Fc-ARMs that target prostate cancer (Fc-ARM-Ps). Fc-ARM-Ps recruited antibodies to cancer cells expressing prostate-specific membrane antigen but did so with lower efficiency compared with Fc-ARMs targeting the folate receptor. Upon recruitment by Fc-ARM-P, defucosylated antibodies efficiently activated natural killer cells and induced ADCC, whereas antibodies with intact N-glycans did not. The results suggest that the affinity between recruited antibodies and CD16a, a type of Fc receptor expressed on immune cells, could be a key factor controlling immune activation in the Fc-ARM strategy.

Evaluation of a Synergistic Effect of L-Arginine on the Anticancer Activity of Doxorubicin by Using a Co-culture System

In the early stage of tumor development, tumor-associated macrophages (TAM) works to suppress tumor growth by secreting soluble factors including nitric oxide (NO). L-Arginine (Arg) is a substrate of nitric oxide synthase (NOS) expressed in TAM. Here we examined whether NO produced from Arg by macrophages works to enhance the effect of the anti-cancer drug, doxorubicin (Dox) by using a co-culture system of cancer cells with macrophages. By employing colorimetric analyses methods (Griess Reagent and Cell Counting kit-8), we found that NO produced from Arg by co-cultured macrophages could enhance the cytotoxic effect of Dox to cancer cells. Moreover, we found that augmentation is affected by the order of the addition of Arg and Dox. A prior addition of Arg to Dox and simultaneous addition showed the same enhancement effect, but a prior addition of Dox to Arg abolished the augmentation. This suggests that the co-administration of Arg with Dox would be an effective treatment to improve chemo-therapies.

Development of a novel molecular probe for the detection of liver mitochondrial redox metabolism

Redox status influences the course of the inflammatory, metabolic, and proliferative liver diseases. Oxidative stress is thought to play a crucial and sustained role in the pathological progression of early steatosis to severe hepatitis, fibrosis, cirrhosis, and hepatocellular carcinoma. Oxidative stress induced by reactive oxygen species which are generated in the mitochondria can lead to chronic organelle damage in hepatocytes. Currently, the diagnosis of liver disease requires liver biopsy, which is invasive and associated with complications. The present report describes the development of a novel molecular probe, EDA-PROXYL, with higher reactivity and mitochondrial selectivity than standard carboxyl-PROXYL and carbamoyl-PROXYL probes. The membrane permeability of our probe improved in aqueous environments which led to increased accumulation in the liver and interaction of EDA-PROXYL with the carnitine transporter via the amine (NH3+) group further increased accumulation. This increased mitochondrial sensitivity and enhanced accumulation highlight the potential of EDA-PROXYL as a molecular probe for determining metabolic reactions of the mitochondria. Thus, this novel probe could be a tool for the evaluation of redox status of the mitochondria to assess the degree of liver injury and, ultimately, the response to pharmacological therapy.

Blood retention and antigenicity of polycarboxybetaine-modified liposomes

Zwitterionic polycarboxybetaines (PCBs) have gained attention as alternative stealth polymers whose liposomal formulation and protein conjugates were reported not to elicit anti-polymer antibodies. Here, we studied the blood retention and antigenicity of liposomes modified with PCBs focusing on their chemical structures and doses. We compared PCBs with either 1 or 3 (PCB1 or PCB3) spacer carbons between the carboxylate and ammonium groups. PCB3-modified liposomes had a short blood retention, whereas PCB1-modified liposomes demonstrated extended blood retention that was somewhat superior to PEGylated liposome. This confirmed the excellent non-fouling nature of PCB1 reported previously. Interestingly, PCB1-liposome as well as PCB3-liposome elicited specific IgMs toward each PCB. The dose-dependent production of specific IgMs to PCB-liposomes was similar to that of PEGylated liposome, i.e., high doses of PCB-liposomes reduced the production of specific IgMs, termed immunological tolerance. These results indicate the importance of investigating the effect of dose to clarify the existence of antigenicity of stealth polymers.

Synthesis of peptide conjugates with vitamins for induction of antigen-specific immunotolerance

In this report, we designed conjugates of an antigen peptide with the immunosuppressive vitamins all-trans retinoic acid (ATRA) and vitamin D3 for efficient induction of antigen-specific immunotolerance. We established a synthetic scheme for the preparation of the peptide-vitamin conjugates, which the chemically unstable vitamins tolerated. Among the obtained conjugates, the ATRA conjugate successfully suppressed inflammatory effects in macrophages and dendritic cells and induced antigen presentation in dendritic cells. This synthetic method of conjugate is conceivably applicable to other antigen peptides for induction of antigen-specific immunotolerance.

β-Galactosidase-Catalyzed Fluorescent Reporter Labeling of Living Cells for Sensitive Detection of Cell Surface Antigens

The ability to detect cell surface proteins using fluorescent-dye-labeled antibodies is crucial for the reliable identification of many cell types. However, the different types of cell surface proteins used to identify cells are currently limited in number because they need to be expressed at high levels to exceed background cellular autofluorescence, especially in the shorter-wavelength region. Herein we report on a new method, quinone methide-based catalyzed labeling for signal amplification (CLAMP), in which the fluorescence signal is amplified by an enzymatic reaction that strongly facilitates the detection of cell surface proteins on living cells. We used β-galactosidase as an amplification enzyme and designed a substrate for it, called MUGF, that contains a fluoromethyl group. Upon removal of the galactosyl group in MUGF by β-galactosidase labeling of the target cell surface proteins, the resulting product containing the quinone methide group was found to be both cell-membrane-permeable and reactive with intracellular nucleophiles, thereby providing fluorescent adducts. Using this method, we successfully detected several cell surface proteins, including programmed death ligand 1 protein, which is difficult to detect using conventional fluorescent-dye-labeled antibodies.

Modification of nitric oxide donors onto a monoclonal antibody boosts accumulation in solid tumors

Although monoclonal antibodies (mAbs) have revolutionized cancer treatment, their accumulation in solid tumors is limited and requires improvement to enhance therapeutic efficacy. Here we developed a strategy to modify mAb with a donor of nitric oxide (NO) because NO functions to vasodilate as well as to enhance the permeability of vascular endothelium, which will contribute to enhancing the tumor accumulation of mAb. We selected S-nitrosothiol as a NO donor and established the procedure to modify S-nitrosothiol group on mAb under ambient conditions. The modified mAb (Ab-SNO) thus obtained released NO in a preferable speed and maintained its original properties such as binding affinity to a target antigen and efficacy to induce antibody-dependent cellular cytotoxicity. We demonstrated that Ab-SNO enhanced the tumor accumulation of co-administered proteins such as antibody and serum albumin.

AB0387 TREATMENT STATUS FOR OSTEOPOROSIS IN PATIENTS WITH SYSTEMIC LUPUS ERYTHEMATOSUS: CROSS-SECTIONAL ANALYSIS FROM A LUPUS REGISTRY OF NATIONWIDE INSTITUTIONS (LUNA)

Background:

Osteoporosis is one of the most important adverse effects of glucocorticoids in patients with systemic lupus erythematosus (SLE). Because osteoporosis is accelerated by chronic kidney disease (CKD), more attention should be paid to the treatment for osteoporosis in SLE patients with CKD. Many treatment options for osteoporosis have emerged recently, but treatment status in patients with SLE is not elucidated.

Objectives:

The purpose of this study is to elucidate the treatment status for osteoporosis in patients with SLE among the CKD stages.

Methods:

Using data from lupus registry of nationwide institutions (LUNA), a cross-sectional analysis was performed. We firstly described treatment status for osteoporosis in all enrolled patients. Secondary, treatment status for osteoporosis was compared among CKD stages. Finally, bone damage in Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index (SDI) was compared among CKD stages.

Results:

The median age (interquartile range [IQR]) of enrolled 917 patients was 44 (34- 57) years and 809 patients (88%) were female. CKD stages were follows: CKD stage 1, 234 (26%); CKD stage 2, 465 (51%); CKD stage 3, 189 (21%); CKD stage 4, 9 (1%); CKD stage 5, 16 (2%). Median (IQR) age, female sex, and median (IQR) previous maximum dose of prednisolone in patients with and without CKD (≥CKD stage 3) were 56 (46.5-66) and 41 (32-50), 191 (89%) and 615 (88%), and 40 (30-60) and 40 (30-55) mg/day, respectively. Bisphosphonate was administered in 388 (42%) patients, vitamin D supplements in 448 (49%), Ca supplements in 36 (4%), denosumab in 20 (2%) and teriparatide in 14 (2%), respectively. Of enrolled patients, any treatment for osteoporosis was not administered in 226 (25%) patients. In spite of more frequent bone damage in patients with CKD compared to those without CKD (15% vs 10%, p=0.036), treatment status did not differ between patients with and without CKD (bisphosphonate: 41% vs 46%, p=0.29; vitamin D supplements: 50% vs 44%, p=0.14).

Conclusion:

About a quarter of patients with SLE did not take any treatment for osteoporosis. Treatment for osteoporosis might be strengthened to prevent bone damage in SLE patients with CKD.

Disclosure of Interests:

KEN-EI SADA Speakers bureau: I received speaker’s fee from GSK and Astra Zeneca K.K., Keigo Hayashi: None declared, Yosuke ASANO: None declared, Yu Katayama: None declared, Sumie Hiramatsu Asano: None declared, Keiji Ohashi: None declared, Michiko Morishita: None declared, Haruki Watanabe: None declared, Mariko Narazaki: None declared, Yoshinori Matsumoto: None declared, Nobuyuki Yajima: None declared, Ryusuke Yoshimi: None declared, Yasuhiro Shimojima: None declared, Shigeru Ono: None declared, Hiroshi Kajiyama: None declared, Kunihiro Ichinose: None declared, Shuzo Sato: None declared, Michio Fujiwara: None declared, Jun Wada: None declared

Protection of gut microbiome from antibiotics: development of a vancomycin-specific adsorbent with high adsorption capacity

The fraction of administered antibiotics that reach the cecum and colon causes dysbiosis of the gut microbiome, resulting in various diseases. Protection of the gut microbiome from antibiotics using antibiotic adsorbents in the cecum and colon is a promising method to overcome this issue. Previously, activated charcoal (AC) has been reported to protect the gut microbiome of host animals. AC is an adsorbent that is widely used to capture toxic compounds and overdosed drugs in the gastrointestinal tract. The specificity of adsorbents for antibiotics is critical to avoid the risk of unexpected side effects caused by nonspecific adsorption of biological compounds in the intestinal fluid, such as bile acids and essential micronutrients. Here, we have developed specific adsorbents for vancomycin (VCM), which is known to cause gut dysbiosis. The adsorbents were composed of polyethyleneglycol-based microparticles (MPs) in which a specific ligand for VCM, D-Ala-D-Ala-OH, was attached via dendrons of D-lysine to raise the content of the ligand in the MPs. The MPs successfully protected Staphylococcus lentus from VCM in vitro because of the adsorption of VCM in the culture media. Pre-administration of MPs to mice reduced the amount of free VCM in the feces to an undetectable level. This treatment minimized the effect of VCM on gut microbiota and provided protection against Clostridioides difficile infection after oral challenge with spores.

Fc-binding antibody-recruiting molecules exploit endogenous antibodies for anti-tumor immune responses

Redirecting endogenous antibodies in the bloodstream to tumor cells using synthetic molecules is a promising approach to trigger anti-tumor immune responses. However, current molecular designs only enable the use of a small fraction of endogenous antibodies, limiting the therapeutic potential. Here, we report Fc-binding antibody-recruiting molecules (Fc-ARMs) as the first example addressing this issue. Fc-ARMs are composed of an Fc-binding peptide and a targeting ligand, enabling the exploitation of endogenous antibodies through constant affinity to the Fc region of antibodies, whose sequence is conserved in contrast to the Fab region. We show that Fc-ARM targeting folate receptor-α (FR-α) redirects a clinically used antibody mixture to FR-α⁺ cancer cells, resulting in cancer cell lysis by natural killer cells in vitro. Fc-ARMs successfully interacted with antibodies in vivo and accumulated in tumors. Furthermore, Fc-ARMs recruited antibodies to suppress tumor growth in a mouse model. Thus, Fc-ARMs have the potential to be a novel class of cancer immunotherapeutic agents.

Fc-binding antibody-recruiting molecules provide robust and sufficient opportunities to employ endogenous antibodies for anti-tumor immune responses.

Fluorescence Signal Amplification by Using β-Galactosidase for Flow Cytometry; Advantages of an Endogenous Activity-Free Enzyme

We previously proposed using a hydrolysis enzyme for fluorescent signal amplification in flow cytometric detection of antigen proteins, which was named the catalyzed reporter penetration (CARP) method. In this method, antigen proteins are labeled with enzyme-modified antibodies, and then fluorophore-modified substrates stain cells by penetrating the cell membrane upon hydrolysis of the substrate. We proved the concept by using alkaline phosphatase (AP) as the hydrolysis enzyme. However, a required prior inactivation process of endogenous AP activity on the cell surface risked disrupting recognition of antigen proteins by antibodies. In this report, the CARP method was extended to β-galactosidase (β-gal) as an amplification enzyme, which circumvented the requirement of an initial inactivation process because endogenous β-gal activity on the surface of examined cells was found to be negligible. The substrate structure for β-gal was optimized and used for the CARP method. The CARP method showed significantly higher fluorescent signals than a conventional method using fluorophore-modified antibodies. Moreover, the degree of amplification of the fluorescence signal was higher for antigens with low expression levels, showing that the CARP method is a suitable signal amplification method over current conventional approaches.

Induction of ADCC by a folic acid–mAb conjugate prepared by tryptophan-selective reaction toward folate-receptor-positive cancer cells

We developed conjugates between monoclonal antibody (mAb) and folic acid (FA) by using a tryptophan (Trp)-selective reaction, which yields relatively homogenous products compared to conventional methods. The obtained mAb–FA conjugates showed significant cellular cytotoxicity toward folate receptor-expressing cancer cells, demonstrating that the conjugates retained the Fc region's original function.

mAb–folic acid conjugates were prepared by a tryptophan-selective reaction using an organic radical under ambient conditions, which showed significant induction ability of antibody-dependent cellular cytotoxicity.

P3576Histopathological validation of optical coherence tomography assessment for cholesterol crystals

Background

Cholesterol crystals (CCs) are well recognized as one of important components of advanced atherosclerotic plaques. Whilethe consensus document for intravascular optical coherence tomography (OCT) has proposed that CCs are appeared as thin, linear regions of high-signal intensity within a plaque, no study has validated CCs assessment by OCT in comparison with histopathology.

Purpose

Thepurpose of this study was to validate OCT assessments of CCs with histopathology.

Methods

A total of 27 diseased coronary artery samples (10–20 mm length) were resected from 7 randomly selected cadavers. OCT imaging was performed for the samples. Then, arterial samples were fixed in 10% formalin for ≥48 hours, decalcified and processed for standard paraffin embedding. Sections 5μm thick were sliced at the ink-marked imaging sites and stained with hematoxylin and eosin, and Masson's Trichrome. An independent pathologist blinded to the OCT results diagnosed all of the plaques. Subsequently, the OCT images were interpreted by an observer blinded to the histological results. In the OCT assessment, CCs were defined as thin, linear regions of high-signal intensity within a plaque.

Results

We obtained 27 pairs of OCT/ histopathology. CCs were diagnosed by histology in 10 (37%) of the 27 pairs. The sensitivity and specificity of OCT for detecting CCs were 60% and 94%, respectively.

Conclusion

OCT has a high specificity but modest sensitivity for detection of CCs in comparison with histopathology. CCs diagnosed with OCT would help the identification of advanced atherosclerotic plaques.

Acknowledgement/Funding

JSPS KAKENHI 17K09557