Development of a 1:1-binding biparatopic anti-TNFR2 antagonist by reducing signaling activity through epitope selection

Conventional bivalent antibodies against cell surface receptors often initiate unwanted signal transduction by crosslinking two antigen molecules. Biparatopic antibodies (BpAbs) bind to two different epitopes on the same antigen, thus altering crosslinking ability. In this study, we develop BpAbs against tumor necrosis factor receptor 2 (TNFR2), which is an attractive immune checkpoint target. Using different pairs of antibody variable regions specific to topographically distinct TNFR2 epitopes, we successfully regulate the size of BpAb-TNFR2 immunocomplexes to result in controlled agonistic activities. Our series of results indicate that the relative positions of the two epitopes recognized by the BpAb are critical for controlling its signaling activity. One particular antagonist, Bp109-92, binds TNFR2 in a 1:1 manner without unwanted signal transduction, and its structural basis is determined using cryo-electron microscopy. This antagonist suppresses the proliferation of regulatory T cells expressing TNFR2. Therefore, the BpAb format would be useful in designing specific and distinct antibody functions.

Assessment of feline hospitalization environment using a one-way mirror

A separate, cat-specific hospitalization room away from dogs is recommended to reduce stress in cats; however, this can be difficult for some hospitals to provide. In such cases, measures are undertaken to reduce the cat's stress by providing a place to hide. However, inability to observe the cat's condition may be an obstacle to providing veterinary care. The use of a one-way mirror to create a sheltered environment while allowing observation of the cats was assessed. Five healthy cats were assessed using the Cat Stress Score (CSS) while in a cage with either a transparent panel or a one-way mirror. No significant differences in the CSS between the transparent panel and one-way mirror were observed. Variations in the CSS scores depended on the cat's personality, with friendlier and more sociable cats showing a lower CSS with the one-way mirror. A one-way mirror may be useful to reduce stress in hospitalized cats.

Manufacturing carbon storage sintered body using microwave-selective and high-speed heating techniques

Microwave sintering of fly ash samples with large amounts of unburned carbon and CaCO₃ was examined in this study. To this end, CaCO₃ was mixed with fly ash sintered body to fix CO₂. The decomposition of CaCO₃ was observed when the raw material was heated to 1000 °C using microwave irradiation; however, a sintered body containing aragonite was obtained when the raw material was heated to 1000 °C with added water. Further, carbides in the fly ash could be selectively heated by controlling the microwave irradiation. The microwave magnetic field created a temperature gradient of 100 °C in a narrow region of 2.7 μm or less in the sintered body, and it helped suppress the CaCO₃ decomposition in the mixture during sintering. By storing water in the gas phase before spreading, CaCO₃, which is difficult to sinter using conventional heating, can be sintered without decomposing.

Purification and CryoEM Image Analysis of the Bacterial Flagellar Filament

The bacterial flagellum is a large assembly of about 30 different proteins and is divided into three parts: the filament that acts as a screw propeller, the hook as a universal joint, and the basal body as a rotary motor. In the case of Salmonella, the filament length is 10-15 μm, which is more than ten times longer than the size of the cell. The filament is composed of only one component protein, flagellin, and is made of 11 protofilaments. The filament can form 12 different supercoiled structures as polymorphic forms. Each protofilament can take either the L (left-handed) or R (right-handed) state, and the number ratio of the protofilaments in these two states determines the shape of the supercoil. Some point mutations in flagellin make the filament straight by making all the protofilaments in one of the two states. The straight filaments enable us to use their helical symmetries for structural analysis by electron cryomicroscopy (cryoEM) and single particle image analysis. Here, we describe the methods for the purification of the flagellar filament and cryoEM data collection and image analysis.

Isolation and structure of the fibril protein, a major component of the internal ribbon for Spiroplasma swimming

Spiroplasma, which are known pathogens and commensals of arthropods and plants, are helical-shaped bacteria that lack a peptidoglycan layer. Spiroplasma swim by alternating between left- and right-handed helicity. Of note, this system is not related to flagellar motility, which is widespread in bacteria. A helical ribbon running along the inner side of the helical cell should be responsible for cell helicity and comprises the bacterial actin homolog, MreB, and a protein specific to Spiroplasma, fibril. Here, we isolated the ribbon and its major component, fibril filament, for electron microscopy (EM) analysis. Single-particle analysis of the fibril filaments using the negative-staining EM revealed a three-dimensional chain structure composed of rings with a size of 11 nm wide and 6 nm long, connected by a backbone cylinder with an 8.7 nm interval with a twist along the filament axis. This structure was verified through EM tomography of quick-freeze deep-etch replica sample, with a focus on its handedness. The handedness and pitch of the helix for the isolated ribbon and fibril filament agreed with those of the cell in the resting state. Structures corresponding to the alternative state were not identified. These results suggest that the helical cell structure is supported by fibril filaments; however, the helical switch is caused by the force generated by the MreB proteins. The isolation and structural outline of the fibril filaments provide crucial information for an in-depth clarification of the unique swimming mechanism of Spiroplasma.

Structures of Multisubunit Membrane Complexes With the CRYO ARM 200

Progress in structural membrane biology has been significantly accelerated by the ongoing ‘Resolution Revolution’ in cryo-electron microscopy (cryo-EM). In particular, structure determination by single-particle analysis has evolved into the most powerful method for atomic model building of multisubunit membrane protein complexes. This has created an ever-increasing demand in cryo-EM machine time, which to satisfy is in need of new and affordable cryo-electron microscopes. Here, we review our experience in using the JEOL CRYO ARM 200 prototype for the structure determination by single-particle analysis of three different multisubunit membrane complexes: the Thermus thermophilus V-type ATPase V_O complex, the Thermosynechococcus elongatus photosystem I monomer and the flagellar motor lipopolysaccharide peptidoglycan ring (LP ring) from Salmonella enterica.

ADC Level is Related to DWI Reversal in Patients Undergoing Mechanical Thrombectomy: A Retrospective Cohort Study

BACKGROUND AND PURPOSE

In patients with ischemic stroke, DWI lesions can occasionally be reversed by reperfusion therapy. This study aimed to ascertain the relationship between ADC levels and DWI reversal in patients with acute ischemic stroke who underwent recanalization treatment.

MATERIALS AND METHODS

We conducted a retrospective cohort study in patients with acute ischemic stroke who underwent endovascular mechanical thrombectomy with successful recanalization between April 2017 and March 2021. DWI reversal was assessed through follow-up MR imaging approximately 24 hours after treatment.

RESULTS

In total, 118 patients were included. DWI reversal was confirmed in 42 patients. The ADC level in patients with reversal was significantly higher than that in patients without reversal. Eighty-three percent of patients with DWI reversal areas had mean ADC levels of ≥520 × 10^-6 mm²/s, and 71% of patients without DWI reversal areas had mean ADC levels of <520 × 10^-6 mm²/s. The mean ADC threshold was 520 × 10^-6 mm²/s with a sensitivity and specificity of 71% and 83%, respectively. In multivariate analysis, the mean ADC level (OR, 1.023; 95% CI, 1.013-1.033; P < .0001) was independently associated with DWI reversal. Patients with DWI reversal areas had earlier neurologic improvement (NIHSS at 7 days) than patients without reversal areas (P < .0001).

CONCLUSIONS

In acute ischemic stroke, the ADC value is independently associated with DWI reversal. Lesions with a mean ADC of ≥520 × 10^-6 mm²/s are salvageable by mechanical thrombectomy, and DWI reversal areas regain neurologic function. The ADC value is easily assessed and is a useful tool to predict viable lesions.

Multiple electron transfer pathways of tungsten-containing formate dehydrogenase in direct electron transfer-type bioelectrocatalysis

Tungsten-containing formate dehydrogenase from Methylorubrum extroquens AM1 (FoDH1)—a promising biocatalyst for the interconversion of carbon dioxide/formate and nicotine adenine dinucleotide (NAD+)/NADH redox couples—was investigated from structural biology and bioelectrochemistry. FoDH1...

Effect of HIV infection on pre- and post-liver transplant mortality in patients with organ failure

OBJECTIVES

Organ failure (OF), a leading cause of death in HIV-positive individuals, is common in patients undergoing liver transplantation (LT). We examined the impact of HIV infection on pre- and post-LT mortalities in cirrhotic patients stratified by the number and type of OFs.

METHODS

We performed a cross-sectional study and a retrospective cohort study using the US National Inpatient Sample (NIS) and the United Network for Organ Sharing (UNOS) registry data, respectively. Patients who had not yet undergone LT from the NIS database (2010-2014) and patients undergoing LT from the UNOS database (2003-2016) were included in the study.

RESULTS

Analysis of patients (201 348) from the NIS database showed that one [adjusted odds ratio (aOR) 1.531; 95% confidence interval (CI) 1.160-2.023], two (aOR 1.624; 95% CI 1.266-2.083) or three or more OFs (aOR 1.349; 95% CI 1.165-1.562) were associated with higher pre-LT mortality in HIV-infected patients compared with HIV-negative patients with the corresponding number of OFs. In patients without OF, HIV infection was not associated with increased pre-LT mortality. UNOS data for patients undergoing LT (38 942) showed that the presence of two or more OFs was associated with increased post-LT 1-year mortality in HIV-infected patients compared with non-HIV-infected patients with the corresponding number of OFs (aOR 2.342; 95% CI 1.576-3.480). However, in patients with no OF or only one OF, HIV infection was not associated with increased post-LT 1-year mortality (aOR 1.372; 95% CI 0.911-2.068).

CONCLUSIONS

The results of this study emphasize the importance of preventing OF development, and justify LT for HIV-infected patients with no or only one OF.

Nationwide study of surgery for primary infected abdominal aortic and common iliac artery aneurysms

BACKGROUND

Primary infected aneurysms of the abdominal aorta and iliac arteries are potentially life-threatening. However, because of the rarity of the disease, its pathogenesis and optimal treatment strategy remain poorly defined.

METHODS

A nationwide retrospective cohort study investigated patients who underwent surgical treatment for a primary infected abdominal aortic and/or common iliac artery (CIA) aneurysm between 2011 and 2017 using a Japanese clinical registry. The study evaluated the relationships between preoperative factors and postoperative outcomes including 90-day and 3-year mortality, and persistent or recurrent aneurysm-related infection. Propensity score matching was used to compare survival between patients who underwent in situ prosthetic grafting and those who had endovascular aneurysm repair (EVAR).

RESULTS

Some 862 patients were included in the analysis. Preceding infection was identified in 30.2 per cent of the patients. The median duration of postoperative follow-up was 639 days. Cumulative overall survival rates at 30 days, 90 days, 1 year, 3 years and 5 years were 94.0, 89.7, 82.6, 74.9 and 68.5 per cent respectively. Age, preoperative shock and hypoalbuminaemia were independently associated with short-term and late mortality. Compared with open repair, EVAR was more closely associated with persistent or recurrent aneurysm-related infection (odds ratio 2.76, 95 per cent c.i. 1.67 to 4.58; P < 0.001). Propensity score-matched analyses demonstrated no significant differences between EVAR and in situ graft replacement in terms of 3-year all-cause and aorta-related mortality rates (P = 0.093 and P =0.472 respectively).

CONCLUSION

In patients undergoing surgical intervention for primary infected abdominal aortic and CIA aneursyms, postoperative survival rates were encouraging. Eradication of infection following EVAR appeared less likely than with open repair, but survival rates were similar in matched patients between EVAR and in situ graft replacement.

Risk prediction model for early outcomes of revascularization for chronic limb-threatening ischaemia

BACKGROUND

Quantifying the risks and benefits of revascularization for chronic limb-threatening ischaemia (CLTI) is important. The aim of this study was to create a risk prediction model for treatment outcomes 30 days after revascularization in patients with CLTI.

METHODS

Consecutive patients with CLTI who had undergone revascularization between 2013 and 2016 were collected from the JAPAN Critical Limb Ischemia Database (JCLIMB). The cohort was divided into a development and a validation cohort. In the development cohort, multivariable risk models were constructed to predict major amputation and/or death and major adverse limb events using least absolute shrinkage and selection operator logistic regression. This developed model was applied to the validation cohort and its performance was evaluated using c-statistic and calibration plots.

RESULTS

Some 2906 patients were included in the analysis. The major amputation and/or mortality rate within 30 days of arterial reconstruction was 5.0 per cent (144 of 2906), and strong predictors were abnormal white blood cell count, emergency procedure, congestive heart failure, body temperature of 38°C or above, and hemodialysis. Conversely, moderate, low or no risk in the Geriatric Nutritional Risk Index (GNRI) and ambulatory status were associated with improved results. The c-statistic value was 0.82 with high prediction accuracy. The rate of major adverse limb events was 6.4 per cent (185 of 2906), and strong predictors were abnormal white blood cell count and body temperature of 38°C or above. Moderate, low or no risk in the GNRI, and age greater than 84 years were associated with improved results. The c-statistic value was 0.79, with high prediction accuracy.

CONCLUSION

This risk prediction model can help in deciding on the treatment strategy in patients with CLTI and serve as an index for evaluating the quality of each medical facility.

The clinical impact of preoperative body composition differs between male and female colorectal cancer patients

AIM

Patient body composition is an important indicator of metabolic status and is associated with cancer progression. Because body composition varies between men and women, we aimed to examine the difference in clinical impact of preoperative body composition according to sex.

METHOD

We used an integrated dataset of 559 colorectal cancer (CRC) patients. The association between preoperative body composition indices [body mass index (BMI), visceral to subcutaneous fat area ratio (VSR) and skeletal muscle index (SMI)] and patient outcome, clinicopathological factors and preoperative inflammation and nutritional status was analysed, comparing men and women.

RESULTS

Preoperative low BMI and low SMI in men was significantly associated with unfavourable overall survival (OS) [BMI: hazard ratio (HR) 2.22, 95% CI 1.28-4.14, P = 0.004; SMI: HR 2.54, 95% CI 1.61-4.07, P < 0.001] and high VSR in women was significantly associated with unfavourable OS (HR 1.79, 95% CI 1.03-3.02, P = 0.040). Additionally, low SMI in men was significantly associated with deeper tumour invasion and greater distant metastasis and high VSR in women was significantly associated with advanced age, right-sided tumour, lower total lymphocyte count and lower albumin levels. Interestingly, low BMI in men was significantly associated with deeper tumour invasion, but also with favourable inflammation and nutritional status (lower C-reactive protein and higher albumin).

CONCLUSION

The clinical impact of preoperative body composition differed between men and women: SMI in men and VSR in women were good prognosticators. Our findings may provide a novel insight for CRC treatment strategies.

Structure of the native supercoiled flagellar hook as a universal joint

The Bacterial flagellar hook is a short supercoiled tubular structure made from a helical assembly of the hook protein FlgE. The hook acts as a universal joint that connects the flagellar basal body and filament, and smoothly transmits torque generated by the rotary motor to the helical filament propeller. In peritrichously flagellated bacteria, the hook allows the filaments to form a bundle behind the cell for swimming, and for the bundle to fall apart for tumbling. Here we report a native supercoiled hook structure at 3.6 Å resolution by cryoEM single particle image analysis of the polyhook. The atomic model built into the three-dimensional (3D) density map reveals the changes in subunit conformation and intersubunit interactions that occur upon compression and extension of the 11 protofilaments during their smoke ring-like rotation. These observations reveal how the hook functions as a dynamic molecular universal joint with high bending flexibility and twisting rigidity.

105Calcified nodule in coronary artery: clinical features and prognosis with optical coherence tomography-guided percutaneous coronary intervention

Background

Calcified nodule (CN) in coronary artery is known to be a significant factor for stent underexpansion, however, its baseline characteristics and long-term prognosis is unclear.

Method

421 consecutive severe calcified lesions (Defined as maximum calcium arc >180 degrees) which underwent optical coherence tomography (OCT)-guided percutaneous coronary intervention (PCI) were analyzed between January 2013 and December 2017. We investigated baseline characteristics and OCT parameter (maximum arc of calcium, maximum thickness of calcium, and length of calcium) and long-term clinical outcome (Major adverse cardiac event (MACE), any cause of death, acute myocardial infarction (AMI) and target vessel failure (TVF)). Median follow up period was 33.7 months.

Result

CN was seen in 22.3% (94 lesions) of all severe calcified lesions. Baseline characteristics and OCT parameters were significantly different in CN and non-CN groups (Hemodialysis; 23.6% vs. 14.1%, p=0.03, Multivessel Disease; 57.4% vs. 44.6, p=0.03, maximum arc of calcium; 305.4 vs. 286.1, p=0.02, maximum thickness of calcium (μm); 1206.2 vs 1123.8, p=0.01, length of calcium (mm); 24.6 vs. 19.0, p=0.01). CN lesions was strongly associated poor long-term clinical outcome (MACE; 50.5% vs. 25.7%, p<0.01), any cause of death; 18.1% vs. 9.5%, p=0.02, AMI; 7.4% vs. 2.4%, p=0.02, TVF; 38.3% vs. 19.2%, p<0.01).

Conclusion

Hemodialysis, multivessel disease and abundant calcium component may have accompanied with CN which may result in poor long-term prognosis.

P3577Predictors analysis of restenosis in calcified nodule with OCT-guided PCI

Background

Recent reports show that stenting for coronary calcified nodule (CN) resulted in frequent in-stent restenosis, however, its predictors are unclear.

Method

117 consecutive calcified nodule lesions which underwent optical coherence tomography (OCT)-guided PCI were analyzed between January 2013 and March 2018. We investigated baseline characteristics and OCT parameter in CN site (Arc of CN, Lumen area and Symmetry index before and after PCI).

Result

CN site in-stent restenosis was seen 35 lesions (29.9%). Baseline characteristics was significantly different between restenosis group and non-restenosis group (Age; 68.9y.o vs. 73.3y.o, p=0.01, diabetes mellitus; 80.0% vs. 57.3%, Chronic Kidney Disease (CKD); 74.3% vs. 36.6%, Hemodialysis; 54.3% vs. 12.2%). Arc of CN before PCI in restenosis group was larger than that in non-restenosis group (122.7 vs. 110.0 degrees, p=0.01). Post stent symmetry index in restenosis group was smaller than that in non-restenosis group (0.64 vs. 0.75, p<0.01).

Conclusion

Younger patients, diabetes mellitus, CKD, hemodialysis, arc of CN before PCI, post stent symmetry index may be predictors of CN site restenosis.

Novel Insights into Conformational Rearrangements of the Bacterial Flagellar Switch Complex

The flagellar motor can spin in both counterclockwise (CCW) and clockwise (CW) directions. The flagellar motor consists of a rotor and multiple stator units, which act as a proton channel. The rotor is composed of the transmembrane MS ring made of FliF and the cytoplasmic C ring consisting of FliG, FliM, and FliN. The C ring is directly involved in rotation and directional switching. The Salmonella FliF-FliG deletion fusion motor missing 56 residues from the C terminus of FliF and 94 residues from the N terminus of FliG keeps a domain responsible for the interaction with the stator intact, but its motor function is reduced significantly. Here, we report the structure and function of the FliF-FliG deletion fusion motor. The FliF-FliG deletion fusion not only resulted in a strong CW switch bias but also affected rotor-stator interactions coupled with proton translocation through the proton channel of the stator unit. The energy coupling efficiency of the deletion fusion motor was the same as that of the wild-type motor. Extragenic suppressor mutations in FliG, FliM, or FliN not only relieved the strong CW switch bias but also increased the motor speed at low load. The FliF-FliG deletion fusion made intersubunit interactions between C ring proteins tighter compared to the wild-type motor, whereas the suppressor mutations affect such tighter intersubunit interactions. We propose that a change of intersubunit interactions between the C ring proteins may be required for high-speed motor rotation as well as direction switching.IMPORTANCE The bacterial flagellar motor is a bidirectional rotary motor for motility and chemotaxis, which often plays an important role in infection. The motor is a large transmembrane protein complex composed of a rotor and multiple stator units, which also act as a proton channel. Motor torque is generated through their cyclic association and dissociation coupled with proton translocation through the proton channel. A large cytoplasmic ring of the motor, called C ring, is responsible for rotation and switching by interacting with the stator, but the mechanism remains unknown. By analyzing the structure and function of the wild-type motor and a mutant motor missing part of the C ring connecting itself with the transmembrane rotor ring while keeping a stator-interacting domain for bidirectional torque generation intact, we found interesting clues to the change in the C ring conformation for the switching and rotation involving loose and tight intersubunit interactions.

The impact of preoperative anaemia and anaemic subtype on patient outcome in colorectal cancer

AIM

Preoperative anaemia is associated with adverse outcomes in colorectal cancer (CRC). To clarify the reason for this we aimed to comprehensively assess the association of preoperative anaemia with tumour characteristics, host systemic inflammation and nutrition status, and perioperative blood transfusion.

METHOD

We used an integrated database of 592 CRC patients. The association of preoperative anaemic subtype, calculated from haemoglobin and erythrocyte mean corpuscular volume levels, with patient outcome, preoperative serum data relating to systemic inflammation and nutrition and perioperative blood transfusion was analysed.

RESULTS

Preoperative anaemia was significantly associated with poorer overall survival and relapse-free survival (RFS); in particular microcytic anaemia had a trend to poorer RFS than other forms of anaemia (P = 0.0648). In addition, preoperative anaemia was significantly correlated with right-sided tumours, greater depth of tumour invasion, use of neoadjuvant chemotherapy, poorer prognostic nutritional index and higher modified Glasgow Prognostic Score (mGPS). Microcytic anaemia in particular had a strong association with a greater depth of tumour invasion (P = 0.0072) and higher mGPS (P = 0.0058) than other causes of anaemia. Perioperative blood transfusion for CRC patients with anaemia was associated with adverse outcomes.

CONCLUSIONS

Preoperative anaemia, especially microcytic anaemia, was associated with poor patient outcomes, possibly due to poor systemic inflammatory and nutritional status, and it was not improved by perioperative blood transfusion. Our data suggest that preoperative anaemia and the anaemic subtype may serve as an easily available predictor of outcome in CRC.

Identification and initial characterization of novel neural immediate early genes possibly differentially contributing to foraging-related learning and memory processes in the honeybee

Despite possessing a limited number of neurones compared to vertebrates, honeybees show remarkable learning and memory performance, an example being 'dance communication'. In this phenomenon, foraging honeybees learn the location of a newly discovered food source and transmit the information to nestmates by symbolic abdomen vibrating behaviour, leading to navigation of nestmates to the new food source. As an initial step toward understanding the detailed molecular mechanisms underlying the sophisticated learning and memory performance of the honeybee, we focused on the neural immediate early genes (IEGs), which are specific genes quickly transcribed after neural activity without de novo protein synthesis. Although these have been reported to play an essential role in learning and memory processes in vertebrates, far fewer studies have been performed in insects in this regard. From RNA-sequencing analysis and subsequent assays, we identified three genes, Src homology 3 (SH3) domain binding kinase, family with sequence similarity 46 and GB47136, as novel neural IEGs in the honeybee. Foragers and/or orientating bees, which fly around their hives to memorize the positional information, showed induced expression of these IEGs in the mushroom body, a higher-order centre essential for learning and memory, indicating a possible role for the novel IEGs in foraging-related learning and memory processes in the honeybee.

ADAMTS13 activity and genetic mutations in Japan

Thrombotic thrombocytopenic purpura (TTP), a life threatening disease, can be induced by congenital or acquired deficiency of plasma metalloprotease ADAMTS13. Since the publication of the first genetic analysis in patients with congenital ADAMTS13 deficiency in 2001, more than 100 genetic defects in the ADAMTS13 gene have been reported worldwide. Genetic analysis in patients with ADAMTS13 deficiency has greatly contributed to the understanding of the etiology of TTP. A rapid and quantitative assay method for the plasma ADAMTS13 activity was developed recently in 2005 and opened a new area of TTP research – namely genetic research using a general population to evaluate age and gender differences of ADAMTS13 activity as well as phenotype – genotype correlations of genetic polymorphisms and estimation of a homozygote or a compound heterozygote ADAMTS13 deficiencies. The Japanese general population study included 3616 individuals with an age between 30 – 80 years confirming other studies that while ADAMTS13 activity decreased with age, VWF antigen increased and VWF antigen levels are lowest in blood group O indviduals, whereas ADAMTS13 activity levels were not associated with the AB0 blood group. 25 polymorphisms with a minor allele frequency of more than 0.01 were found, among them 6 missense mutations and 19 synonymous mutations, except P475S missense polymorphisms that was only idenitified in an East Asian population, characterized by reduced ADAMTS13 activity. Prevalence of congenital ADAMTS13 deficiency in the Japanese population was estimated about one individual in 1.1 × 106 to be homozygote or compound heterozygote for ADAMTS13 deficiency. So far more than 40 mutations in Japanese congenital TTP patients were found, but R193W, Q449*, C754Afs*24 (c.2259delA) and C908Y were identified in more than four patients suggesting the precipitaion of these mutations in the Japanese population.

Live imaging of extracellular signal-regulated kinase and protein kinase A activities during thrombus formation in mice expressing biosensors based on Förster resonance energy transfer

Essentials Spatiotemporal regulation of protein kinases during thrombus formation remains elusive in vivo. Activities of protein kinases were live imaged in mouse platelets at laser-ablated arterioles. Protein kinase A was activated in the dislodging platelets at the downstream side of the thrombus. Extracellular signal-regulated kinase was activated at the core of contracting platelet aggregates.

SUMMARY

Background The dynamic features of thrombus formation have been visualized by conventional video widefield microscopy or confocal microscopy in live mice. However, owing to technical limitations, the precise spatiotemporal regulation of intracellular signaling molecule activities, which have been extensively studied in vitro, remains elusive in vivo. Objectives To visualize, by the use of two-photon excitation microscopy of transgenic mice expressing Förster resonance energy transfer (FRET) biosensors for extracellular signal-regulated kinase (ERK) and protein kinase A (PKA), ERK and PKA activities during thrombus formation in laser-injured subcutaneous arterioles. Results When a core of densely packed platelets had developed, ERK activity was increased from the basal region close to the injured arterioles. PKA was activated at the downstream side of an unstable shell overlaying the core of platelets. Intravenous administration of a MEK inhibitor, PD0325901, suppressed platelet tethering and dislodged platelet aggregates, indicating that ERK activity is indispensable for both initiation and maintenance of the thrombus. A cAMP analog, dbcAMP, inhibited platelet tethering but failed to dislodge the preformed platelet aggregates, suggesting that PKA can antagonize thrombus formation only in the early phase. Conclusion In vivo imaging of transgenic mice expressing FRET biosensors will open a new opportunity to visualize the spatiotemporal changes in signaling molecule activities not only during thrombus formation but also in other hematologic disorders.

Activation of the hypoxia-inducible factor pathway induced by prolyl hydroxylase domain 2 deficiency enhances the effect of running training in mice

AIMS

Hypoxic response mediated by hypoxia-inducible factor (HIF) seems to contribute to the benefit of endurance training. To verify the direct contribution of HIF activation to running training without exposure to atmospheric hypoxia, we used prolyl hydroxylase domain 2 (PHD2) conditional knockout mice (cKO), which exhibit HIF activation independent of oxygen concentration, and we examined their maximal exercise capacity before and after 4 weeks of treadmill exercise training.

METHODS

Phd2^f/f mice (n = 26) and Phd2 cKO mice (n = 24) were randomly divided into two groups, trained and untrained, and were subjected to maximal running test before and after a 4-week treadmill-training regimen.

RESULTS

Prolyl hydroxylase domain 2 deficiency resulted in HIF-α protein accumulation. Phd2 cKO mice exhibited marked increases in haematocrit values and haemoglobin concentrations, as well as an increase in the capillary number in the skeletal muscle. The 4-week training elicited an increase in the capillary-to-fibre (C/F) ratio and succinyl dehydrogenase activity of the skeletal muscle. Importantly, trained Phd2 cKO mice showed a significantly greater improvement in running time than trained control mice (P < 0.05). Collectively, these data suggest that the combination of training and the activation of the HIF pathway are important for maximizing the effect of running training.

CONCLUSION

We conclude that the activation of the HIF pathway induced by PHD2 deficiency enhances the effect of running training.

Straight and rigid flagellar hook made by insertion of the FlgG specific sequence into FlgE

The bacterial flagellar hook connects the helical flagellar filament to the rotary motor at its base. Bending flexibility of the hook allows the helical filaments to form a bundle behind the cell body to produce thrust for bacterial motility. The hook protein FlgE shows considerable sequence and structural similarities to the distal rod protein FlgG; however, the hook is supercoiled and flexible as a universal joint whereas the rod is straight and rigid as a drive shaft. A short FlgG specific sequence (GSS) has been postulated to confer the rigidity on the FlgG rod, and insertion of GSS at the position between Phe-42 and Ala-43 of FlgE actually made the hook straight. However, it remains unclear whether inserted GSS confers the rigidity as well. Here, we provide evidence that insertion of GSS makes the hook much more rigid. The GSS insertion inhibited flagellar bundle formation behind the cell body, thereby reducing motility. This indicates that the GSS insertion markedly reduced the bending flexibility of the hook. Therefore, we propose that the inserted GSS makes axial packing interactions of FlgE subunits much tighter in the hook to suppress axial compression and extension of the protofilaments required for bending flexibility.

Girdin maintains the stemness of glioblastoma stem cells

This corrects the article DOI: 10.1038/onc.2011.466.

Structural stability of flagellin subunit affects the rate of flagellin export in the absence of FliS chaperone

FliS chaperone binds to flagellin FliC in the cytoplasm and transfers FliC to a sorting platform of the flagellar type III export apparatus through the interaction between FliS and FlhA for rapid and efficient protein export during flagellar filament assembly. FliS also suppresses the secretion of an anti-σ factor, FlgM. Loss of FliS results in a short filament phenotype although the expression levels of FliC are increased considerably due to an increase in the secretion level of FlgM. Here to clarify the rate limiting step of FliC export in the absence of FliS, we isolated bypass mutants from a Salmonella ΔfliS mutant. All the bypass mutations were identified in FliC. These bypass mutations increased the export rate of FliC by ca. twofold, allowing the bypass mutant cells to produce longer filaments than the parental ΔfliS cells. Both far-UV CD measurements and limited proteolysis revealed that the bypass mutations significantly destabilize the folded structure of FliC monomer. These results suggest that an unfolding step of FliC limits the export rate of FliC in the ΔfliS mutant, thereby producing short filaments. We propose that FliS promotes FliC docking at the FlhA platform to facilitate subsequent unfolding of FliC.

Functional analysis of recombinant 2-Cys peroxiredoxin from the hard tick Haemaphysalis longicornis

Ticks are obligate haematophagous arthropods that feed on vertebrate blood containing high levels of iron. The host-derived iron reacts to oxygen in the tick's body, and then high levels of reactive oxygen species, including hydrogen peroxide (H(2)O(2)), may be generated. High levels of H(2)O(2) cause oxidative stress to aerobic organisms. Therefore, antioxidant responses are necessary to control H(2)O(2). We focused on peroxiredoxins (Prxs), H(2)O(2) -scavenging enzymes. The sequence of Haemaphysalis longicornis 2-Cys Prx (HlPrx2) was identified from fat body cDNA libraries of this tick and recombinant HlPrx2 was then prepared using Escherichia coli. By comparison with the 2-Cys Prxs of other organisms, we found two conserved cysteines in HlPrx2, Cys51 and Cys172. We examined the antioxidant activity of HlPrx2 and mutant proteins produced by a single base substitution, converting one or both of these cysteines into serines. The assays revealed that proteins containing Cys51 showed antioxidant activity when H(2)O(2) was removed. Sodium dodecyl sulphate polyacrylamide gel electrophoresis and size-exclusion chromatography demonstrated that only the wild-type HlPrx2 formed homodimers and that all of the proteins that we made had a high molecular weight peak. These results indicate that both Cys51 and Cys172 are essential for the dimerization of HlPrx2, whereas only the Cys51 residue is necessary for antioxidant activity.

Novel Nonsense Mutation in the NLRP7 Gene Associated with Recurrent Hydatidiform Mole

AIM

This study aimed to clarify the genetic and epigenetic features of recurrent hydatidiform mole (RHM) in Japanese patients.

METHODS

Four Japanese isolated RHM cases were analyzed using whole-exome sequencing. Villi from RHMs were collected by laser microdissection for genotyping and DNA methylation assay of differentially methylated regions (DMRs). Single nucleotide polymorphisms of PEG3 and H19 DMRs were used to confirm the parental origin of the variants.

RESULTS

A novel homozygous nonsense mutation in NLRP7 (c.584G>A; p.W195X) was identified in 1 patient. Genotyping of one of her molar tissue revealed that it was biparental but not androgenetic in origin. Despite the fact that the RHM is biparental, maternally methylated DMRs of PEG3, SNRPN and PEG10 showed complete loss of DNA methylation. A paternally methylated DMR of H19 retained normal methylation.

CONCLUSIONS

This is the first Japanese case of RHM with a novel homozygous nonsense NLRP7 mutation and a specific loss of maternal DNA methylation of DMRs. Notably, the mutation was identified in an isolated case of an ethnic background that has not previously been studied in this context. Our data underscore the involvement of NLRP7 in RHM pathophysiology and confirm that DNA methylation of specific regions is critical.

The Beneficial Effects of the DPP-4 Inhibitor Alogliptin on Hemoglobin A1c and Serum Lipids in Japanese Patients with Type 2 Diabetes

It has been reported that dipeptidyl peptidase-4 (DPP-4) inhibitors improve hemoglobin A1c (HbA1c) levels in diabetic patients and may also improve the serum lipids. However, few studies have examined relationship between the effects of the DPP-4 inhibitor and the pretreatment HbA1c levels in diabetic patients. Furthermore, it has been reported that prolonged treatment with DPP-4 inhibitors may make glycemic control difficult in some patients. In the present study, we investigated (1) the effect of the DPP-4 inhibitor alogliptin on HbA1c, blood glucose (BG), and serum lipid in Japanese patients with type 2 diabetes, (2) the relationship between the HbA1c levels at baseline and the effects of alogliptin, and (3) the effects of switching of the DPP-4 inhibitor to alogliptin after 12 months' administration of sitagliptin on glycemic control and serum lipids. After 6-months' treatment with alogliptin, we found reductions of HbA1c, BG, and serum total cholesterol, and LDL cholesterol levels. Pretreatment level of HbA1c was well correlated with the degree of reduction of both HbA1c and BG levels after the treatment. Also, alogliptin kept levels of HbA1c and BG reduced by sitagliptin for 12 months, and relapsing of these levels and serum lipids were not observed. This study revealed that alogliptin improved HbA1c, BG, and serum lipid profiles in type 2 diabetic patients, and the effect of alogliptin on HbA1c and BG levels was correlated with HbA1c level at pretreatment. Furthermore, long-term treatment with alogliptin did not cause relapsing of glycemic control and serum lipids.

DPP-4 Inhibitor Teneligliptin Improves Insulin Resistance and Serum Lipid Profile in Japanese Patients with Type 2 Diabetes

Dipeptidyl peptidase-4 (DPP-4) inhibitors have been reported to improve the glycemic control and blood hemoglobin A1c (HbA1c) concentrations. However, there are few reports as yet suggesting that DPP-4 inhibitors may also improve insulin resistance and the serum lipid profile in the clinical setting. This study was aimed at investigating the effect of 14-week treatment with teneligliptin (20 mg/day) on the homeostasis model assessment ratio (HOMA-R), an indicator of insulin resistance, and serum lipid profile in 9 patients with type 2 diabetes. The treatment produced a significant decrease of the blood glucose and HbA1c concentration (blood glucose: p=0.008; HbA1c: p=0.038), and also improved HOMA-R (p=0.039). Furthermore, the patients showed elevation of the serum HDL-cholesterol level (p=0.032), and a tendency towards reduction of the serum triglyceride level. The results indicate that teneligliptin acts not only to improve the blood glucose control, but also to improve the insulin resistance and serum lipid profile in Japanese type 2 diabetes patients.

Usefulness of the Bollinger scoring method in evaluating peripheral artery angiography with 64-low computed tomography in patients with peripheral arterial disease

AIM

There are various angiographic and runoff scoring systems for evaluating stenosis and arterial occlusion in patients with peripheral artery disease (PAD). The report from the BASIL trial revealed that the Bollinger scoring system, originally designed to classify intra-arterial digital subtraction angiography (IADSA), was sensitive to differences in PAD. The purpose of the present study was to evaluate the application of the Bollinger scoring system to a 64-low multidetector computed tomography (MDCT) in PAD patients.

METHODS

Patients with PAD who underwent both a 64-MDCT and DSA within a 4-year period were enrolled in the study. Two observers analyzed the MDCT and DSA images for each patient. We divided the arterial tree from the common iliac artery to the plantar arch into 16 segments and scored 0-15 points for each segment as reported by Bollinger, according to the severity and extent of disease. We analyzed the reliability of differences in scores between the DSA and MDCT by the intraclass correlation coefficients (ICCs).

RESULTS

We reviewed 100 consecutive patients (127 limbs) and assessed a total of 1929 segments. The Bollinger score of the 2 tests were same in 39.6% of all segments. The difference between the 2 tests were within 2 points in 77.3% of the above-knee segments (70.1-91.6% in each segments), 58.8% of the below-knee segments with the exception of plantar arch (42-74%). The ICC values showed relatively good reliability, but in the CFA the ICC values showed poor reliability.

CONCLUSION

The Bollinger scoring method is a useful tool to evaluate peripheral artery angiography with 64-low CT in patients with PAD.

Prognosis of arterial aneurysm after surgery in patients with Behçet's disease

AIM

Despite improvements in therapeutic modalities, the treatment of arterial aneurysms complicating Behçet's disease (BD) is still challenging. This study examined the long-term prognosis after surgery for arterial aneurysms in BD.

METHODS

This study included 9 patients with BD (8 men and 1 woman) who underwent surgery for arterial aneurysms between 1989 and 2008. The outcomes after the surgical intervention were assessed, including procedure-related complications and survival.

RESULTS

The initial surgical procedures were performed for aortic or iliac aneurysms in 5 patients and for lower-extremity aneurysms in 4 patients. There was no operative mortality. The mean follow-up period was 135±69 months, ranging from 53 to 259 months. Patients with aortic or iliac aneurysms underwent graft interposition with Dacron prostheses. Their postoperative courses were uneventful, and all patients were alive during the follow-up with no procedure-related complications. Those treated for lower-extremity aneurysms tended to show perioperative and postoperative complications, including aneurysmal degeneration of the autogenous vein graft in 2 patients. One patient who initially underwent surgery for a popliteal artery aneurysm died due to the rupture of a dissecting aortic aneurysm after serial surgical interventions for multiple aneurysms. Concomitant aortic or iliac aneurysms in 2 patients were followed up without any change in size under medical treatment using colchicine and corticosteroids.

CONCLUSION

Although we cannot draw a firm conclusion because of the small number of cases in the present series, graft interposition can lead to a favorable prognosis in BD patients with aortic or iliac aneurysms, whereas surgical treatment of BD-related lower-extremity aneurysms is frequently associated with short- and long-term postoperative complications. Immunosuppressive therapy might possibly improve treatment outcomes.

Photoresponsive DNA nanocapsule having an open/close system for capture and release of nanomaterials

A photofunctionalized square bipyramidal DNA nanocapsule (NC) was designed and prepared for the creation of a nanomaterial carrier. Photocontrollable open/close system and toehold system were introduced into the NC for the inclusion and release of a gold nanoparticle (AuNP) by photoirradiation and strand displacement. The reversible open and closed states were examined by gel electrophoresis and atomic force microscopy (AFM), and the open behavior was directly observed by high-speed AFM. The encapsulation of the DNA-modified AuNP within the NC was carried out by hybridization of a specific DNA strand (capture strand), and the release of the AuNP was examined by addition of toehold-containing complementary DNA strand (release strand). The release of the AuNP from the NC was achieved by the opening of the NC and subsequent strand displacement.

DNA methylation analysis of human myoblasts during in vitro myogenic differentiation: de novo methylation of promoters of muscle-related genes and its involvement in transcriptional down-regulation

Although DNA methylation is considered to play an important role during myogenic differentiation, chronological alterations in DNA methylation and gene expression patterns in this process have been poorly understood. Using the Infinium HumanMethylation450 BeadChip array, we obtained a chronological profile of the genome-wide DNA methylation status in a human myoblast differentiation model, where myoblasts were cultured in low-serum medium to stimulate myogenic differentiation. As the differentiation of the myoblasts proceeded, their global DNA methylation level increased and their methylation patterns became more distinct from those of mesenchymal stem cells. Gene ontology analysis revealed that genes whose promoter region was hypermethylated upon myoblast differentiation were highly significantly enriched with muscle-related terms such as 'muscle contraction' and 'muscle system process'. Sequence motif analysis identified 8-bp motifs somewhat similar to the binding motifs of ID4 and ZNF238 to be most significantly enriched in hypermethylated promoter regions. ID4 and ZNF238 have been shown to be critical transcriptional regulators of muscle-related genes during myogenic differentiation. An integrated analysis of DNA methylation and gene expression profiles revealed that de novo DNA methylation of non-CpG island (CGI) promoters was more often associated with transcriptional down-regulation than that of CGI promoters. These results strongly suggest the existence of an epigenetic mechanism in which DNA methylation modulates the functions of key transcriptional factors to coordinately regulate muscle-related genes during myogenic differentiation.

Efficacy of revascularization for critical limb ischemia in patients with end-stage renal disease

OBJECTIVE

To evaluate the outcomes of surgical revascularization for critical limb ischemia in patients with end-stage renal disease (ESRD).

PATIENTS AND METHODS

From 2004 to 2010, 184 patients with 213 critically ischaemic limbs caused by arteriosclerosis were admitted to The University of Tokyo Hospital. The outcomes of primarily surgical revascularization-based treatments were retrospectively compared in patients with ESRD (ESRD group: 79 patients, 101 limbs) and without ESRD (non-ESRD group: 105 patients, 112 limbs) during the same period.

RESULTS

Arterial reconstruction was performed on 56 limbs in 46 patients in the ESRD group and 78 limbs in 73 patients in the non-ESRD group (55% vs. 70%; p = .03). Major amputation was performed in 6 of 48 limbs with patent grafts in the ESRD group because of uncontrolled infection or progression of necrosis. The limb salvage rate after arterial reconstruction was significantly lower in the ESRD group than in the non-ESRD group (p = .0019). The postoperative survival rate was lower in the ESRD group than in the non-ESRD group, although this difference was not significant (p = .052). Associated cardiovascular disease and systemic infection were the most frequent causes of death in the ESRD group. There was no significant difference in graft patency between the two groups after distal bypass surgery; however, the limb salvage rate was significantly lower in the ESRD group than in the non-ESRD group (p = .03).

CONCLUSIONS

Critical limb ischemia associated with ESRD has a poor prognosis. Infection control is particularly important for achievement of good treatment outcomes.

Array-comparative genomic hybridization profiling of immunohistochemical subgroups of diffuse large B-cell lymphoma shows distinct genomic alterations

Diffuse large B-cell lymphoma (DLBCL) displays striking heterogeneity at the clinical, genetic and molecular levels. Subtypes include germinal center B-cell-like (GCB) DLBCL and activated B-cell-like (ABC) DLBCL, according to microarray analysis, and germinal center type or non-germinal center type by immunohistochemistry. Although some reports have described genomic aberrations based upon microarray classification system, genomic aberrations based upon immunohistochemical classifications have rarely been reported. The present study aimed to ascertain the relationship between genomic aberrations and subtypes identified by immunohistochemistry, and to study the pathogenetic character of Chinese DLBCL. We conducted immunohistochemistry using antibodies against CD10, BCL6 and MUM1 in 59 samples of DLBCL from Chinese patients, and then performed microarray-based comparative genomic hybridization for each case. Characteristic genomic differences were found between GCB and non-GCB DLBCL from the array data. The GCB type was characterized by more gains at 7q (7q22.1, P < 0.05) and losses at 16q (P ≤ 0.05), while the non-GCB type was characterized by gains at 11q24.3 and 3q13.2 (P < 0.05). We found completely different mutations in BCL6+ and BCL6− non-GCB type DLBCL, whereby the BCL6− group had a higher number of gains at 1q and a loss at 14q32.13 (P ≤ 0.005), while the BCL6+ group showed a higher number of gains at 14q23.1 (P = 0.15) and losses at 6q (P = 0.07). The BCL6− group had a higher frequency of genomic imbalances compared to the BCL6+ group. In conclusion, the BCL6+ and BCL6− non-GCB type of DLBCL appear to have different mechanisms of pathogenesis.