Alteration of Membrane Physicochemical Properties by Two Factors for Membrane Protein Integration

After a nascent chain of a membrane protein emerges from the ribosomal tunnel, the protein is integrated into the cell membrane. This process is controlled by a series of proteinaceous molecular devices, such as signal recognition particles and Sec translocons. In addition to these proteins, we discovered two endogenous components regulating membrane protein integration in the inner membrane of Escherichia coli. The integration is blocked by diacylglycerol (DAG), whereas the blocking is relieved by a glycolipid named membrane protein integrase (MPIase). Here, we investigated the influence of these integration-blocking and integration-promoting factors on the physicochemical properties of membrane lipids via solid-state NMR and fluorescence measurements. These factors did not have destructive effects on membrane morphology because the membrane maintained its lamellar structure and did not fuse in the presence of DAG and/or MPIase at their effective concentrations. We next focused on membrane flexibility. DAG did not affect the mobility of the membrane surface, whereas the sugar chain in MPIase was highly mobile and enhanced the flexibility of membrane lipid headgroups. Comparison with a synthetic MPIase analog revealed the effects of the long sugar chain on membrane properties. The acyl chain order inside the membrane was increased by DAG, whereas the increase was cancelled by the addition of MPIase. MPIase also loosened the membrane lipid packing. Focusing on the transbilayer movement, MPIase reduced the rapid flip-flop motion of DAG. On the other hand, MPIase could not compensate for the diminished lateral diffusion by DAG. These results suggest that by manipulating the membrane lipids dynamics, DAG inhibits the protein from contacting the inner membrane, whereas the flexible long sugar chain of MPIase increases the opportunity for interaction between the membrane and the protein, leading to membrane integration of the newly formed protein

Biological responses according to the shape and size of carbon nanotubes in BEAS-2B and MESO-1 cells

This study aimed to investigate the influence of the shape and size of multi-walled carbon nanotubes (MWCNTs) and cup-stacked carbon nanotubes (CSCNTs) on biological responses in vitro. Three types of MWCNTs - VGCF (R)-X, VGCF (R)-S, and VGCF (R) (vapor grown carbon fibers; with diameters of 15, 80, and 150 nm, respectively) - and three CSCNTs of different lengths (CS-L, 20-80 mu m; CS-S, 0.5-20 mu m; and CS-M, of intermediate length) were tested. Human bronchial epithelial (BEAS-2B) and malignant pleural mesothelioma cells were exposed to the CNTs (1-50 mu g/mL), and cell viability, permeability, uptake, total reactive oxygen species/superoxide production, and intracellular acidity were measured. CSCNTs were less toxic than MWCNTs in both cell types over a 24-hour exposure period. The cytotoxicity of endocytosed MWCNTs varied according to cell type/size, while that of CSCNTs depended on tube length irrespective of cell type. CNT diameter and length influenced cell aggregation and injury extent. Intracellular acidity increased independently of lysosomal activity along with the number of vacuoles in BEAS-2B cells exposed for 24 hours to either CNT (concentration, 10 mu g/mL). However, total reactive oxygen species/superoxide generation did not contribute to cytotoxicity. The results demonstrate that CSCNTs could be suitable for biological applications and that CNT shape and size can have differential effects depending on cell type, which can be exploited in the development of highly specialized, biocompatible CNTs.ArticleINTERNATIONAL JOURNAL OF NANOMEDICINE. 9:1979-1990 (2014)journal articl

B^0_{d,s} - \bar{B}^0_{d,s} mass-differences from QCD spectral sum rules

We present the first QCD spectral sum rules analysis of the SU(3) breaking parameter \xi and an improved estimate of the renormalization group invariant (RGI) bag constant \hat{B}_{B_q} both entering into the B^0_{d,s} - \bar{B}^0_{d,s} mass-differences. The averages of the results from the Laplace and moment sum rules to order \alpha_s are f_B\sqrt{\hat B_B} \simeq (247 \pm 59) MeV and \xi \equiv f_{B_s} \sqrt{\hat B_{B_s}} / f_{B} \sqrt{\hat B_{B}} \simeq (1.18\pm 0.03), in units where f_\pi=130.7 MeV. Combined with the experimental data on the mass-differences \Delta M_{d,s}, one obtains the constraint on the CKM weak mixing angle |V_{ts}/V_{td}|^2 > 20.0 (1.1). Alternatively, using the weak mixing angle from the analysis of the unitarity triangle and the data on \Delta M_d, one predicts \Delta M_s=18.6 (2.2) ps^{-1} in agreement with the present experimental lower bound and within the reach of Tevatron 2.Comment: 7 pages with 2 figures, uses espcrc2.sty. Version to appear in Phys. Lett.

悪性褐色細胞腫患者の生存と化学療法の効果

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Successful management of preoperatively diagnosed torsion of a subserosal uterine fibroid by pneumoperitoneum laparoscopic single-port surgery

Objective: Preoperative diagnosis and successful management of acute torsion of a subserosal fibroid by using appropriate imaging modalities and single-port laparoscopic surgery. Case report: A 44-year-old nulliparous woman presented with lower abdominal pain. Computed tomography and magnetic resonance imaging with contrast enhancement revealed a tumor in the pouch of Douglas with a low contrast at the center and thin-rim enhancement. Torsion of a uterine subserosal fibroid was diagnosed preoperatively. Laparoscopic single-port surgery by pneumoperitoneum was performed. Torsion of the pedicle attached to the uterine wall was excised by bipolar coagulation and cut with scissors. The extirpated fibroid was extracted from the umbilical wound. The pneumoperitoneum single-port laparoscopic surgery was completed as a gynecologic emergency operation. Conclusion: Torsional uterine fibroids are difficult to diagnose preoperatively as symptoms are nonspecific and need emergent surgical management as an acute abdomen. Preoperative diagnosis using appropriate imaging modalities is important to perform single-port laparoscopic surgery

Organ accumulation and carcinogenicity of highly dispersed multi-walled carbon nanotubes administered intravenously in transgenic rasH2 mice

Purpose: Multiwalled carbon nanotubes (MWCNTs) have been known to enter the circulatory system via the lungs from inhalation exposure; however, its carcinogenicity and subsequent accumulation in other organs have not been adequately reported in the literature. Moreover, the safety of MWCNTs as a biomaterial has remained a matter of debate, particularly when the material enters the circulatory system. To address these problems, we used carcinogenic rasH2 transgenic mice to intravenously administer highly dispersed MWCNTs and to evaluate their carcinogenicity and accumulation in the organs. Methods: Two types of MWCNTs (thin-and thick-MWCNTs) were intravenously administered at a high dose (approximately 0.7 mg per kg body weight) and low dose (approximately 0.07 mg per kg body weight). Results: MWCNTs showed pancreatic accumulation in 3.2% of mice administered with MWCNTs, but there was no accumulation in other organs. In addition, there was no significant difference in the incidence of tumor among the four MWCNTs-administered groups compared to the vehicle group without MWCNTs administration. Blood tests revealed elevated levels in mean red blood cell volume and mean red blood cell hemoglobin level for the MWCNTs-administered group, in addition to an increase in eotaxin. Conclusion: The present study demonstrated that the use of current technology to sufficiently disperse MWCNTs resulted in minimal organ accumulation with no evidence of carcinogenicity.ArticleINTERNATIONAL JOURNAL OF NANOMEDICINE. 14:6465-6480 (2019)journal articl

Noninvasive prediction of shunt operation outcome in idiopathic normal pressure hydrocephalus

Idiopathic normal pressure hydrocephalus (iNPH) is a syndrome characterized by gait disturbance, cognitive deterioration and urinary incontinence in elderly individuals. These symptoms can be improved by shunt operation in some but not all patients. Therefore, discovering predictive factors for the surgical outcome is of great clinical importance. We used normalized power variance (NPV) of electroencephalography (EEG) waves, a sensitive measure of the instability of cortical electrical activity, and found significantly higher NPV in beta frequency band at the right fronto-temporo-occipital electrodes (Fp2, T4 and O2) in shunt responders compared to non-responders. By utilizing these differences, we were able to correctly identify responders and non-responders to shunt operation with a positive predictive value of 80% and a negative predictive value of 88%. Our findings indicate that NPV can be useful in noninvasively predicting the clinical outcome of shunt operation in patients with iNPH

Antimicrobial Resistance of Breakthrough-Urinary Tract Infections in Children under Antimicrobial Prophylaxis

Antimicrobial prophylaxis using cefaclor or trimethoprim-sulfamethoxazole (co-trimoxazole) is recommended for children with vesicoureteral reflex (VUR) to prevent recurrent urinary tract infection (UTI). This retrospective study was performed by reviewing the data of children ≥5 years of age treated for recurrent UTI in six hospitals from 2010 to 2015. The criteria for UTI diagnosis is fever (≥38°C) and positive results in urine culture (>104 colony-forming units/ml in midstream or withdrawn urine specimens). In total, 41 children were reviewed, and 31 children had recurrent UTI without antimicrobial prophylaxis and 10 had breakthrough (BT)-UTI treated with prophylaxis using cefaclor or co-trimoxazole. In the cases of BT-UTI treated with prophylaxis, 5 children received cefaclor and 5 received co-trimoxazole. We collected data on pathogens, antimicrobial resistance, and antimicrobial agents chosen for the empirical treatment of recurrent UTI. We also evaluated the validity of empirical therapy for recurrent UTI in this study. Various pathogens were found in children who received prophylaxis with cefaclor. The rate of empirical antimicrobial agents that were inappropriate based on antimicrobial susceptibility tests was higher in children who received prophylaxis with cefaclor (60.0%) than in those who received no prophylaxis (25.9%) or prophylaxis with co-trimoxazole (20.0%). Prophylaxis with cefaclor was found to be a risk factor for inappropriate empirical treatment in BT-UTI cases. The results suggest that the choice of empirical antimicrobial agents in BT-UTI cases should be carefully considered before treatment with prophylaxis. To encourage the adequate use of antimicrobial agents, we recommend prophylaxis with co-trimoxazole to prevent recurrent UTI

Culture medium type affects endocytosis of multi-walled carbon nanotubes in BEAS-2B cells and subsequent biological response

AbstractWe examined the cytotoxicity of multi-walled carbon nanotubes (MWCNTs) and the resulting cytokine secretion in BEAS-2B cells or normal human bronchial epithelial cells (HBEpCs) in two types of culture media (Ham’s F12 containing 10% FBS [Ham’s F12] and serum-free growth medium [SFGM]). Cellular uptake of MWCNT was observed by fluorescent microscopy and analyzed using flow cytometry. Moreover, we evaluated whether MWCNT uptake was suppressed by 2 types of endocytosis inhibitors. We found that BEAS-2B cells cultured in Ham’s F12 and HBEpCs cultured in SFGM showed similar biological responses, but BEAS-2B cells cultured in SFGM did not internalize MWCNTs, and the 50% inhibitory concentration value, i.e., the cytotoxicity, was increased by more than 10-fold. MWCNT uptake was suppressed by a clathrin-mediated endocytosis inhibitor and a caveolae-mediated endocytosis inhibitor in BEAS-2B cells cultured in Ham’s F12 and HBEpCs cultured in SFGM. In conclusion, we suggest that BEAS-2B cells cultured in a medium containing serum should be used for the safety evaluation of nanomaterials as a model of normal human bronchial epithelial cells. However, the culture medium composition may affect the proteins that are expressed on the cytoplasmic membrane, which may influence the biological response to MWCNTs

Cross-ancestry genome-wide analysis of atrial fibrillation unveils disease biology and enables cardioembolic risk prediction

心房細動の遺伝的基盤を解明 --大規模ゲノムデータによる病態解明と遺伝的リスクスコア構築--. 京都大学プレスリリース. 2023-01-20.Atrial fibrillation (AF) is a common cardiac arrhythmia resulting in increased risk of stroke. Despite highly heritable etiology, our understanding of the genetic architecture of AF remains incomplete. Here we performed a genome-wide association study in the Japanese population comprising 9, 826 cases among 150, 272 individuals and identified East Asian-specific rare variants associated with AF. A cross-ancestry meta-analysis of >1 million individuals, including 77, 690 cases, identified 35 new susceptibility loci. Transcriptome-wide association analysis identified IL6R as a putative causal gene, suggesting the involvement of immune responses. Integrative analysis with ChIP-seq data and functional assessment using human induced pluripotent stem cell-derived cardiomyocytes demonstrated ERRg as having a key role in the transcriptional regulation of AF-associated genes. A polygenic risk score derived from the cross-ancestry meta-analysis predicted increased risks of cardiovascular and stroke mortalities and segregated individuals with cardioembolic stroke in undiagnosed AF patients. Our results provide new biological and clinical insights into AF genetics and suggest their potential for clinical applications