High-throughput structure determination of an intrinsically disordered protein using cell-free protein crystallization.

Intrinsically disordered proteins (IDPs) play a crucial role in various biological phenomena, dynamically changing their conformations in response to external environmental cues. To gain a deeper understanding of these proteins, it is essential to identify the determinants that fix their structures at the atomic level. Here, we developed a pipeline for rapid crystal structure analysis of IDP using a cell-free protein crystallization (CFPC) method. Through this approach, we successfully demonstrated the determination of the structure of an IDP to uncover the key determinants that stabilize its conformation. Specifically, we focused on the 11-residue fragment of c-Myc, which forms an α-helix through dimerization with a binding partner protein. This fragment was strategically recombined with an in-cell crystallizing protein and was expressed in a cell-free system. The resulting crystal structures of the c-Myc fragment were successfully determined at a resolution of 1.92 Å and we confirmed that they are identical to the structures of the complex with the native binding partner protein. This indicates that the environment of the scaffold crystal can fix the structure of c-Myc. Significantly, these crystals were obtained directly from a small reaction mixture (30 µL) incubated for only 72 h. Analysis of eight crystal structures derived from 22 mutants revealed two hydrophobic residues as the key determinants responsible for stabilizing the α-helical structure. These findings underscore the power of our CFPC screening method as a valuable tool for determining the structures of challenging target proteins and elucidating the essential molecular interactions that govern their stability.

Crystal structure of the in-cell Cry1Aa purified from Bacillus thuringiensis.

In-cell protein crystals which spontaneously crystallize in living cells, have recently been analyzed in investigations of their structures and biological functions. The crystals have been challenging to analyze structurally because of their small size. Therefore, the number of in-cell protein crystals in which the native structure has been determined is limited because most of the structures of in-cell crystals have been determined by recrystallization after dissolution. Some proteins have been reported to form intermolecular disulfide bonds in natural protein crystals that stabilize the crystals. Here, we focus on Cry1Aa, a cysteine-rich protein that crystallizes in Bacillus thuringiensis (Bt) and forms disulfide bonds. Previously, the full-length structure of 135 kDa Cry1Ac, which is the same size as Cry1Aa, was determined by recrystallization of dissolved protein from crystals purified from Bt cells. However, the formation of disulfide bonds has not been investigated because it was necessary to replace cysteine residues to prevent aggregation of the soluble protein. In this work, we succeeded in direct X-ray crystallographic analysis using crystals purified from Bt cells and characterized the cross-linked network of disulfide bonds within Cry1Aa crystals.

Risk factor structure of heart failure in patients with cancer after treatment with anticancer agents' assessment by big data from a Japanese electronic health record.

As the prognosis of cancer patients has been improved, comorbidity of heart failure (HF) in cancer survivors is a serious concern, especially in the aged population. This study aimed to examine the risk factors of HF development after treatment by anticancer agents, using a machine learning-based analysis of a massive dataset obtained from the electronic health record (EHR) in Japan. This retrospective, cohort study, using a dataset from 2008 to 2017 in the Diagnosis Procedure Combination (DPC) database in Japan, enrolled 140,327 patients. The structure of risk factors was determined using multivariable analysis and classification and regression tree (CART) algorithm for time-to-event data. The mean follow-up period was 1.55 years. The prevalence of HF after anticancer agent administration were 4.0%. HF was more prevalent in the older than the younger. As the presence of cardiovascular diseases and various risk factors predicted HF, CART analysis of the risk factors revealed that the risk factor structures complicatedly differed among different age groups. The highest risk combination was hypertension, diabetes mellitus, and atrial fibrillation in the group aged ≤ 64 years, and the presence of ischemic heart disease was a key in both groups aged 65-74 years and 75 ≤ years. The machine learning-based approach was able to develop complicated HF risk structures in cancer patients after anticancer agents in different age population, of which knowledge would be essential for realizing precision medicine to improve the prognosis of cancer patients.

Early P2Y12 Inhibitor Single Antiplatelet Therapy for High-Bleeding Risk Patients After Stenting　- PENDULUM Mono 24-Month Analysis.

BACKGROUND: In PENDULUM mono, Japanese patients with high bleeding risk (HBR) received short-term dual antiplatelet therapy (DAPT) followed by single antiplatelet therapy (SAPT) with prasugrel after percutaneous coronary intervention (PCI). One-year data from PENDULUM mono showed better outcomes with prasugrel monotherapy after short-term DAPT compared with matched patients in the PENDULUM registry with longer DAPT durations according to guidelines at that time. This study presents 2-year results.Methods and Results: We compared 24-month data from PENDULUM mono (n=1,107; de-escalation strategy group) and the PENDULUM registry (n=2,273; conventional strategy group); both were multicenter, non-interventional, prospective registry studies, using the inverse probability of treatment weighting (IPTW) method. In the PENDULUM mono group, the cumulative incidence of clinically relevant bleeding (CRB) at 24 months post-PCI (primary endpoint) was 6.8%, and that of major adverse cardiac and cerebrovascular events (MACCE) was 8.9%. After IPTW adjustment, the cumulative incidence of CRB was 5.8% and 7.2% in PENDULUM mono and the PENDULUM registry, respectively (hazard ratio [HR] 0.77; 95% confidence interval [CI] 0.57-1.04; P=0.086), and that of MACCE was 8.0% and 9.5%, respectively (HR 0.77; 95% CI 0.59-1.01; P=0.061). CONCLUSIONS: Japanese PCI patients with HBR prescribed prasugrel SAPT after short-term DAPT had a lower ischemic event risk than those prescribed long-term DAPT, and this was particularly relevant for ischemic events after 1 year.

Consensus document on the standard of coronary angioscopy examination and assessment from the Japanese Association of Cardiovascular Intervention and Therapeutics.

Coronary angioscopy (CAS) is a unique diagnostic device that allows direct visualization of the vascular luminal surface in living patients. CAS contributes to elucidate the pathology of coronary artery disease. This consensus document provides a standard for CAS examination and assessment.

Design of an In-Cell Protein Crystal for the Environmentally Responsive Construction of a Supramolecular Filament.

Protein assemblies can be designed for development of nano-bio materials. This has been achieved by modulating protein-protein interactions. However, fabrication of highly ordered protein assemblies remains challenging. Protein crystals, which have highly ordered arrangements of protein molecules, provide useful source matrices for synthesizing artificial protein assemblies. Here, we describe construction of a supramolecular filament structure by engineering covalent and non-covalent interactions in a protein crystal. Performing in-cell crystallization of Trypanosoma brucei cysteine protease cathepsin B (TbCatB), we achieved a precise arrangement of protein molecules while suppressing random aggregation due to disulfide bonds. We succeeded in synthesizing bundled filament from the crystals by autoxidation of cysteinyl thiols after the isolation of the crystals from living cells.

Importance of the length of the myocardial sleeve in the superior vena cava in patients with atrial fibrillation.

BACKGROUND: Pulmonary vein (PV) antrum isolation (PVAI) has proven to be a useful strategy for radiofrequency catheter ablation (RFCA) of atrial fibrillation (AF) worldwide. However, non-PV foci, especially from the superior vena cava (SVC), play an important role in initiating and maintaining AF. METHODS: In all, 427 consecutive patients with non-valvular AF who were admitted to our hospitals to undergo RFCA of AF using an EnSite™ system were evaluated. The length from the top of the sinus node to the top of the myocardial sleeve of SVC (L-SVC), longer and shorter diameter of SVC of 1 cm above of junction of right atrium and SVC, and local activation time (LAT) of SVC were measured. Then, the SVC firing was evaluated by an intravenous administration of isoproterenol and adenosine triphosphate. RESULTS: L-SVC, longer and shorter diameter of SVC, and LAT of SVC were significantly longer in the SVC firing group than non-SVC firing group (P < .05). Moreover, in accordance with the L-SVC, the frequency of the SVC firing significantly increased (P < .001). A univariate analysis and multivariate statistical analysis revealed that L-SVC longer than 37.0 mm (odds ratio 6.39) and longer diameter of SVC (odds ratio 6.78) were independent risk factors for SVC firing in patients with AF who underwent RFCA of AF. CONCLUSIONS: In view of these findings, L-SVC longer than 37.0 mm longer diameter SVC longer than 17.0 mm may be one of the important predictors of SVC firing in patients with AF.

Successful introduction of robotic-assisted percutaneous coronary intervention system into Japanese clinical practice: a first-year survey at single center.

In Japan, a robotic-assisted PCI (R-PCI) system, the CorPath GRX System (Corindus Inc.), has been approved for clinical use in 2018, which is the first introduction of R-PCI into Japan. In this study, the clinical performance of the R-PCI system in the initial year at Kurume University Hospital was evaluated comparing with conventional manual PCI (M-PCI). A total of 30 R-PCI and 77 M-PCI procedures performed between April 2019 and March 2020, were retrospectively included. The primary outcome was the rate of clinical success defined as < 30% residual stenosis without in-hospital major adverse cardiovascular events (MACE). The secondary outcomes were fluoroscopy time, dose area product (DAP), amount of radiation exposure to operators and assistants, procedural time, and contrast volume. Propensity-matching technique was used to match each R-PCI lesion to the nearest M-PCI lesion without replacement. After propensity score matching, 30 R-PCI procedures in 28 patients and 37 M-PCI procedures in 35 patients were analyzed. Clinical success rate with R-PCI was favorable and comparable to M-PCI (93.3 vs. 94.6%, p = 0.97), without any in-hospital MACE. The operator radiation exposure was significantly lower in R-PCI (0 vs. 24.5 µSV, p < 0.0001). Radiation exposure to the patients was tended to be reduced by R-PCI (DAP: 77.6 vs. 100.2 Gycm2, p = 0.07). There were no statistically significant differences in radiation exposure to the assistant, fluoroscopy time, procedural time and contrast volume between the two groups (radiation exposure to the assistant: 10.5 vs. 10.0 µSV, p = 0.64, fluoroscopy time: 27.5 vs. 30.1 min, p = 0.55, procedural time: 72.4 vs. 61.6 min, p = 0.23, and contrast volume: 93.2 vs. 102.0 ml, p = 0.36). R-PCI in selected patients demonstrated favorable clinical outcomes with dramatical reduction of radiation exposure to operators.

Serum interleukin-18 levels as a predictor for patients with genetic dysfunction of cytochrome P450 2C19 in dual antiplatelet therapy with clopidogrel.

BACKGROUND: P2Y12 reaction unit (PRU) is an index of platelet activity upon treatment with clopidogrel. In spite of suitable P2Y12 reactions in dual antiplatelet therapy (DAPT) with clopidogrel after percutaneous coronary intervention (PCI), cardiovascular events actually occur in some patients, possibly due to a genetic dysfunction of cytochrome P450 2C19 (CYP2C19), which is a major metabolic enzyme of clopidogrel. As testing the CYP2C19 phenotypes to predict such patients may lack general versatility in daily clinical practice, the aim of this study was to examine whether measuring the blood levels of some cytokines in patients showing desirable PRUs in DAPT with clopidogrel could be a substitute for testing the CYP2C19 phenotypes. METHODS: We analyzed relationships among PRU, serum levels of 51 cytokines, and CYP2C19 phenotypes in 22 patients receiving DAPT with aspirin and clopidogrel after PCI. RESULTS: Seventeen, 18, and 19 of 22 patients indicated PRU ≤ 208, PRU ≤ 230, and PRU ≤ 262, respectively. Approximately 60% of the patients had a genetically metabolic dysfunction of CYP2C19, and the serum levels of interleukin-18 were independently increased in those patients (p = 0.024 in patients with PRU ≤ 208, p = 0.021 with PRU ≤ 230, and p = 0.020 with PRU ≤ 262). The area under the curves in plot receiver operating characteristics curves for the serum levels of interleukin-18 were 0.94, 0.96, and 0.90 in the non-extensive metabolizer patients with PRU ≤ 208, PRU ≤ 230, and PRU ≤ 262, respectively. CONCLUSIONS: The serum levels of interleukin-18 may be a predictor to diagnose patients who receive undesirable DAPT with clopidogrel, possibly due to the genetic dysfunction of CYP2C19 in spite of suitable P2Y12 reactions after PCI.

Site-Selective Protein Chemical Modification of Exposed Tyrosine Residues Using Tyrosine Click Reaction.

Targeting less abundant amino acid residues on the protein surface may realize site-selective protein modification of natural proteins. The relative hydrophobicity of tyrosine combined with the π-π stacking tendency of the aromatic rings results in generally low accessibility. In this study, site-selective protein modification was achieved by targeting surface-exposed tyrosine residues without using a genetic encoding system. Tyrosine residues were modified with N-methylated luminol derivative under single-electron transfer (SET) reaction conditions. Horseradish peroxidase (HRP)-catalyzed SET and electrochemically activated SET modified surface-exposed tyrosine residues selectively. N-Methylated luminol derivative modified tyrosine residues more efficiently than 4-arylurazole under tyrosine click conditions using HRP and electrochemistry. Tyrosine residues that are evolutionarily exposed only in the complementarity-determining region (CDR) of an antibody were selectively modified by tyrosine click reactions. CDR-modified antibodies were applied to in vivo imaging and antibody-drug conjugated (ADC).

Prasugrel effectively reduces the platelet reactivity units in patients with genetically metabolic dysfunction of cytochrome P450 2C19 who are treated with long-term dual antiplatelet therapy after undergoing drug-eluting stent implantation.

Dual antiplatelet therapy (DAPT) with aspirin and P2Y12 inhibitor is administered following percutaneous coronary intervention (PCI) with coronary stent implantation. Several studies have reported the effects of switching between P2Y12 inhibitors on platelet reactivity (P2Y12 reaction units: PRU), from acute to late phase after PCI. However, the effect of switching at very late phase is unknown. This study examined the effect on PRU in Japanese coronary heart disease patients with long-term DAPT (aspirin + clopidogrel) when switching from clopidogrel to prasugrel. Ninety-six patients were enrolled in this study. The median DAPT duration at enrollment was 1824.0 days. Twenty-three patients with PRU ≥ 208 at enrollment were randomly assigned into either continuing to receive clopidogrel (Continued Group; n = 11) or switching to prasugrel (Switched Group; n = 12). The primary endpoint was the rate of patients who achieved PRU < 208 at the end of 12 weeks of treatment, which was significantly higher in Switched Group relative to Continued Group (90.0% vs. 36.4%; P = 0.024). The secondary endpoint was the PRU at week 12 in groups subdivided according to cytochrome P450 (CYP) 2C19 genotypes. At week 12, extensive metabolizers (EM Group) had 202.3 ± 60.0 and 174.5 ± 22.3 in Continued Group and Switched Group (P = 0.591), respectively; intermediate and poor metabolizers (non-EM Group) had 229.4 ± 36.9 and 148.4 ± 48.4 in Continued Group and Switched Group (P = 0.002), respectively. The PRU for non-EM Group was significantly reduced in Switched Group. Thus, for patients with long-term DAPT (aspirin + clopidogrel) after PCI with coronary stent implantation, switching from clopidogrel to prasugrel resulted in a stable reduction in PRU, regardless of CYP2C19 polymorphism.

Different vascular healing process between bioabsorbable polymer-coated everolimus-eluting stents versus bioresorbable vascular scaffolds via optical coherence tomography and coronary angioscopy (the ENHANCE study: ENdothelial Healing Assessment with Novel Coronary tEchnology).

Recent clinical trials have raised concerns about the safety and efficacy of ABSORB™ bioresorbable vascular scaffolds (BVS). The difference in the vascular healing process between SYNERGY™ bioabsorbable polymer-coated everolimus-eluting stents (BP-EES) and BVS remains unclear. The aim of the ENHANCE study was to compare vascular healing on BP-EES versus BVS by optical coherence tomography (OCT) and coronary angioscopy (CAS) at 4- and 12-month follow-ups. This is a prospective, non-randomized, single center clinical trial. Thirteen eligible patients with multivessel disease were enrolled. BP-EES and BVS were simultaneously implanted in the same patients, but in different coronary vessels. Imaging follow-up with both OCT and CAS was completed in 11 patients at 12 months. Neointimal coverage rates were similar between the two groups based on OCT measurements. The neointimal thickness of BP-EES was significantly thicker at the 12th month than at the 4th month, whereas the neointimal thickness of BVS did not change between the measurements taken at the 4th and 12th month. Existence of intra-stent thrombus was significantly higher in the BVS group, compared to the BP-EES group. On the other hand, CAS revealed that red-thrombi and yellow-plaque were more frequently observed in BVS at 4 months and up to 12-month follow-ups than in BP-EES. These findings suggested that the evidence of instability remained up to 12 months in the vascular healing with BVS, compared to that with BP-EES. Vascular healing of the stented wall was recognized at the very early phase after BP-EES implantation. However, vascular healing with BVS was still incomplete after 12 months.

First Experience of Robotic-assisted Percutaneous Coronary Intervention in Japan.

In 2018, the CorPath GRX system (Corindus) was approved for use in Japan, marking the introduction of the first robotic-assisted system for percutaneous coronary intervention (PCI) in the country. The present report describes the first experience of robotic-assisted PCI for four coronary lesions in two cases in a single center. All procedures succeeded without any complications, although one procedure was converted to manual PCI by the operator's decision. Post-marketing surveillance to assess the impact of this novel system on both Japanese patients and physicians is currently ongoing in Japan.

Coordination design of cadmium ions at the 4-fold axis channel of the apo-ferritin cage.

Spherical protein cages with highly symmetrical structures provide unique environments for the conjugation of metal ions and metal nanoparticles. Ferritin has been widely studied as a template for the coordination of metal ions and metal nanoparticles in fundamental research and applications. However, it remains difficult to design metal coordination sites precisely. In this work, we describe the design and construction of new metal coordination sites by introducing Cys residues at the 4-fold symmetrical hydrophobic channel of apo-ferritin. X-ray crystal structure analyses of the mutants containing Cd(ii) ions show that the four or eight binding sites for Cd(ii) ions are located at the 4-fold symmetrical axis channel of apo-ferritin. It was found that the coordination number and configuration of Cd(ii) ions can be varied by adjusting the positions of the Cys residues at the symmetrical channels of the apo-ferritin cage.

Hybrid training system-induced myokine secretion in healthy men.

The hybrid training system (HTS) is a special and compact system for effective skeletal muscle training by a combined application of volitional and electrical muscle contraction. Lower limbs' muscle training using HTS has been reported to increase not only muscle strength but also plasma interleukin-6 levels; however, little is known in other cytokines. In this study, we measured 52 cytokines and creatine phosphokinase-MM in the serum of 16 healthy men before and after lower limbs' muscle training by the knee flexion and extension using HTS. Skeletal muscle volume-corrected serum concentrations of cutaneous T-cell-attracting chemokine, erythropoietin, and tumor necrosis factor-related apoptosis-inducing ligand increased immediately after the training. These increased cytokines have been reported to play important roles in wound healing, neuroprotection, and cardiovascular protection.

Photoinduced in†Vivo Magnetic Resonance Imaging (MRI) with Rapid CO Release from an MnCO-Protein Needle Composite.

Construction of an artificial protein needle (PN), which includes the membrane puncturing needle domain of bacteriophage T4 conjugated to Mn carbonyl (MnCO) complexes, is reported. The responsiveness to visible light of the MnCO complex makes it useful as a photoinduced in vivo magnetic resonance imaging contrast reagent (MRI CR), because the PN carrier has the potential to deliver the MnCO complex into mouse tumors with retention of coordination structure within the in vivo environment. Moreover, the composite has higher relaxivity and longer circulation as an MRI CR than the corresponding MnCO complex. These results demonstrate construction of a responsive in vivo MRI CR by using an artificial metalloprotein.

Unstable Angina Pectoris in a 22-year-old Female Patient.

Because of the protective effect of estrogen for atherosclerosis, the prevalence of acute coronary syndrome in women before menopause is low. We report a rare case of unstable angina in a young Japanese female who had a history of cigarette smoking and contraceptive use. Her coronary stenosis was successfully treated by percutaneous coronary intervention.

Changes in P2Y12 reaction units after switching treatments from prasugrel to clopidogrel in Japanese patients with acute coronary syndrome followed by elective coronary stenting.

Patients with ischemic heart disease are administered a dual antiplatelet therapy after percutaneous coronary intervention. This consists of aspirin and thienopyridine, which can be switched from prasugrel to clopidogrel. However, the impact of switching is unknown. This study aimed to determine the efficacy and safety of switching from prasugrel to clopidogrel in Japanese patients. One-hundred and thirty-six patients with acute coronary syndrome scheduled to undergo percutaneous coronary intervention and patients with coronary artery disease requiring elective coronary stenting were enrolled. Patients were randomly assigned into the following groups: prasugrel for 6 weeks at loading/maintenance doses of 20/3.75 mg (Continued Group; n = 68) or prasugrel at 20/3.75 mg for 2 weeks followed by clopidogrel at 75 mg for 4 weeks (Switched Group; n = 68). Aspirin (loading dose/maintenance dose 324/81-100 mg/day) was coadministered in both groups. The primary endpoint was the mean P2Y12 reaction unit (PRU) at week 6 and the secondary endpoint was the PRU in groups subdivided based on the presence of CYP2C19 gene polymorphisms. At week 6, the PRU was significantly lower in the Continued Group relative to the Switched Group (140.7 and 183.0, respectively; P < 0.001), which was also evident after correction with the baseline values (144.1 vs. 176.6, respectively; P = 0.005). Extensive and poor metabolizers in the Switched Group, based on CYP2C19 gene polymorphisms, had significantly higher PRU values than those in the Continued Group. Thus, switching treatments from prasugrel to clopidogrel significantly increased the PRU in patients receiving antiplatelet therapy subsequent to percutaneous coronary intervention. Clinical Trial Registration UMIN ID, UMIN000015122.