Dual Effects of Presynaptic Membrane Mimetics on α-Synuclein Amyloid Aggregation.

Aggregation of intrinsically disordered α-synuclein (αSN) under various conditions is closely related to synucleinopathies. Although various biological membranes have shown to alter the structure and aggregation propensity of αSN, a thorough understanding of the molecular and mechanical mechanism of amyloidogenesis in membranes remains unanswered. Herein, we examined the structural changes, binding properties, and amyloidogenicity of three variations of αSN mutants under two types of liposomes, 1,2-Dioleoyl-sn-glycero-3-Phosphocholine (DOPC) and presynaptic vesicle mimetic (Mimic) membranes. While neutrally charged DOPC membranes elicited marginal changes in the structure and amyloid fibrillation of αSNs, negatively charged Mimic membranes induced dramatic helical folding and biphasic amyloid generation. At low concentration of Mimic membranes, the amyloid fibrillation of αSNs was promoted in a dose-dependent manner. However, further increases in the concentration constrained the fibrillation process. These results suggest the dual effect of Mimic membranes on regulating the amyloidogenesis of αSN, which is rationalized by the amyloidogenic structure of αSN and condensation-dilution of local αSN concentration. Finally, we propose physicochemical properties of αSN and membrane surfaces, and their propensity to drive electrostatic interactions as decisive factors of amyloidogenesis.

Bean Extract-Based Gargle for Efficient Diagnosis of Active COVID-19 Infection Using Rapid Antigen Tests.

The antigen-based rapid diagnostic test (Ag-RDT) using saliva specimens is fast, noninvasive, and suitable for SARS-CoV-2 self-testing, unlike nasopharyngeal swab (NPS) testing. We evaluated a novel Beanguard gargle (BG)-based virus collection method that can be applied to Ag-RDT as an alternative to the current RT-PCR with an NPS for early diagnosis of COVID-19. This clinical trial comprised 102 COVID-19-positive patients hospitalized after a governmental screening process and 100 healthy individuals. Paired NPS and BG-based saliva specimens from COVID-19 patients and healthy individuals were analyzed using NPS-RT-PCR, BG-RT-PCR, and BG-Ag-RDTs, whose diagnostic performance for detecting SARS-CoV-2 was compared. BG-Ag-RDTs showed high sensitivity (97.8%) and specificity (100%) in 45 patients within 6 days of illness and detected all cases of SARS-CoV-2 Alpha and Delta variants. In 11 asymptomatic active COVID-19 cases, both BG-Ag-RDTs and BG-RT-PCR showed sensitivities and specificities of 100%. Sensitivities of BG-Ag-RDT and BG-RT-PCR toward salivary viral detection were highly concordant, with no discrimination between symptomatic (97.0%), asymptomatic (100%), or SARS-CoV-2 variant (100%) cases. The intermolecular interactions between SARS-CoV-2 spike proteins and truncated canavalin, an active ingredient from the bean extract (BE), were observed in terms of physicochemical properties. The detachment of the SARS-CoV-2 receptor-binding domain from hACE2 increased as the BE concentration increased, allowing the release of the virus from hACE2 for early diagnosis. Using BG-based saliva specimens remarkably enhances the Ag-RDT diagnostic performance as an alternative to NPS and enables noninvasive, rapid, and accurate COVID-19 self-testing and mass screening, supporting efficient COVID-19 management. IMPORTANCE An Ag-RDT is less likely to be accepted as an initial test method for early diagnosis owing to its low sensitivity. However, our self-collection method, Ag-RDT using BG-based saliva specimens, showed significantly enhanced detection sensitivity and specificity toward SARS-CoV-2 including the Alpha and Delta variants in all patients tested within 6 days of illness. The method represents an attractive alternative to nasopharyngeal swabs for the early diagnosis of symptomatic and asymptomatic COVID-19 cases. The evidence suggests that the method could have a potential for mass screening and monitoring of COVID-19 cases.

Functional Interplay between P5 and PDI/ERp72 to Drive Protein Folding.

P5 is one of protein disulfide isomerase family proteins (PDIs) involved in endoplasmic reticulum (ER) protein quality control that assists oxidative folding, inhibits protein aggregation, and regulates the unfolded protein response. P5 reportedly interacts with other PDIs via intermolecular disulfide bonds in cultured cells, but it remains unclear whether complex formation between P5 and other PDIs is involved in regulating enzymatic and chaperone functions. Herein, we established the far-western blot method to detect non-covalent interactions between P5 and other PDIs and found that PDI and ERp72 are partner proteins of P5. The enzymatic activity of P5-mediated oxidative folding is up-regulated by PDI, while the chaperone activity of P5 is stimulated by ERp72. These findings shed light on the mechanism by which the complex formations among PDIs drive to synergistically accelerate protein folding and prevents aggregation. This knowledge has implications for understanding misfolding-related pathology.

Molecular Effects of Elongation Factor Ts and Trigger Factor on the Unfolding and Aggregation of Elongation Factor Tu Induced by the Prokaryotic Molecular Chaperone Hsp33.

Hsp33, a prokaryotic redox-regulated holding chaperone, has been recently identified to be able to exhibit an unfoldase and aggregase activity against elongation factor Tu (EF-Tu) in its reduced state. In this study, we investigated the effect of elongation factor Ts (EF-Ts) and trigger factor (TF) on Hsp33-mediated EF-Tu unfolding and aggregation using gel filtration, light scattering, circular dichroism, and isothermal titration calorimetry. We found that EF-Tu unfolding and subsequent aggregation induced by Hsp33 were evident even in its complex state with EF-Ts, which enhanced EF-Tu stability. In addition, although TF alone had no substantial effect on the stability of EF-Tu, it markedly amplified the Hsp33-mediated EF-Tu unfolding and aggregation. Collectively, the present results constitute the first example of synergistic unfoldase/aggregase activity of molecular chaperones and suggest that the stability of EF-Tu is modulated by a sophisticated network of molecular chaperones to regulate protein biosynthesis in cells under stress conditions.

Ca2+ Regulates ERp57-Calnexin Complex Formation.

ERp57, a member of the protein disulfide isomerase family, is a ubiquitous disulfide catalyst that functions in the oxidative folding of various clients in the mammalian endoplasmic reticulum (ER). In concert with ER lectin-like chaperones calnexin and calreticulin (CNX/CRT), ERp57 functions in virtually all folding stages from co-translation to post-translation, and thus plays a critical role in maintaining protein homeostasis, with direct implication for pathology. Here, we present mechanisms by which Ca2+ regulates the formation of the ERp57-calnexin complex. Biochemical and isothermal titration calorimetry analyses revealed that ERp57 strongly interacts with CNX via a non-covalent bond in the absence of Ca2+. The ERp57-CNX complex not only promoted the oxidative folding of human leukocyte antigen heavy chains, but also inhibited client aggregation. These results suggest that this complex performs both enzymatic and chaperoning functions under abnormal physiological conditions, such as Ca2+ depletion, to effectively guide proper oxidative protein folding. The findings shed light on the molecular mechanisms underpinning crosstalk between the chaperone network and Ca2+.

A unique leucine-valine adhesive motif supports structure and function of protein disulfide isomerase P5 via dimerization.

P5, also known as PDIA6, is a PDI family member involved in the ER quality control. Here, we revealed that P5 dimerizes via a unique adhesive motif contained in the N-terminal thioredoxin-like domain. Unlike conventional leucine zipper motifs with leucine residues every two helical turns on ∼30-residue parallel α helices, this adhesive motif includes periodic repeats of leucine/valine residues at the third or fourth position spanning five helical turns on 15-residue anti-parallel α helices. The P5 dimerization interface is further stabilized by several reciprocal salt bridges and C-capping interactions between protomers. A monomeric P5 mutant with the impaired adhesive motif showed structural instability and local unfolding, and behaved as aberrant proteins that induce the ER stress response. Disassembly of P5 to monomers compromised its ability to inactivate IRE1α via intermolecular disulfide bond reduction and its Ca2+-dependent regulation of chaperone function in vitro. Thus, the leucine-valine adhesive motif supports structure and function of P5.

Albumin and apolipoprotein H mRNAs in human plasma as potential clinical biomarkers of liver injury: analyses of plasma liver-specific mRNAs in patients with liver injury.

CONTEXT: Plasma liver-specific mRNAs are useful biomarkers of hepatotoxicity in rats. OBJECTIVE: To investigate the potential application of liver-specific mRNAs as biomarkers for liver injury in humans. METHODS: We determined the plasma levels of liver-specific mRNAs by real-time qRT-PCR in healthy donors and patients with liver injury. RESULTS: Plasma levels of albumin (ALB) and apolipoprotein H (APOH) mRNAs increased in patients with elevated serum alanine aminotransferase. These mRNAs also increased in plasma after transcatheter arterial chemoembolization, which induces specific injury to liver. CONCLUSIONS: We demonstrated the potential application of plasma ALB and APOH mRNAs as clinical biomarkers for liver injury.

Wheat and Barley Susceptibility and Tolerance to Multiple Isolates of Wheat streak mosaic virus.

One of the greatest virus disease threats to wheat production in the Great Plains of the USA is Wheat streak mosaic virus (WSMV). Breeding programs have developed wheat varieties that are resistant or tolerant to WSMV infection, but these characteristics are climate dependent, and may also vary by WSMV isolate. We tested 10 spring and nine winter wheat (Triticum aestivum) varieties and two barley (Hordeum vulgare) varieties for resistance and tolerance to one WSMV isolate over four years. In spring wheat and barley, there were year by cultivar interactions in terms of resistance and tolerance. However, in winter wheat, yield losses due to WSMV were relatively consistent across years and varieties. Additionally, we tested the impacts of three WSMV isolates individually and in a mixture on twelve, two, and twelve varieties of spring wheat, barley, and winter wheat, respectively. Resistance and tolerance varied by isolate and cultivar, but there were no isolate by cultivar interactions. For spring wheat and barley, yield impacts were greater for two of the three single isolates than for the isolate mixture, whereas in winter wheat, the isolate mixture caused greater yield losses than the individual isolates. Overall, the results indicate that resistance and tolerance phenotypes were influenced by environmental conditions and by WSMV isolate or combination of isolates, suggesting that cultivar screening should be conducted over multiple years and with multiple virus isolates.

Therapeutic effect of intensive granulocyte and monocyte adsorption apheresis combined with thiopurines for steroid- and biologics-naïve Japanese patients with early-diagnosed Crohn's disease.

BACKGROUND: Early induction with biologics can reduce complications in patients with Crohn's disease (CD) and improve their quality of life. The safety of biologics, however, is uncertain. Granulocyte and monocyte adsorptive apheresis (GMAA) is a natural biologic therapy that selectively removes granulocytes and monocytes/macrophages and has few severe adverse effects. The effects of GMAA on patients with early-diagnosed CD are unclear. We investigated the effects of GMAA combined with thiopurines on patients with early-diagnosed CD. METHODS: Twenty-two corticosteroid- and biologic-naïve patients with active early-diagnosed CD were treated with intensive GMAA (twice per week) combined with thiopurines administration. Active early-diagnosed CD was defined as follows: (i) within 2years after diagnosis of CD, (ii) with no history of both surgical treatment and endoscopic dilation therapy, and (iii) Crohn's Disease Activity Index (CDAI) was higher than 200. We investigated the ratios of clinical remission defined as CDAI was less than or equal to 150 at 2, 4, 6 and 52weeks and mucosal healing defined as a Simplified Endoscopic Activity Score for Crohn's Disease (SES-CD) as 0 at 6 and 52weeks. Adverse events were recorded at each visit. RESULTS: The ratios of clinical remission at 2, 4, and 6 weeks were 6 of 22 (27.2%), 12 of 22 (54.5%), and 17 of 22 (77.2%), respectively. At 52 weeks, 18 of 21 patients (81.8%) were in clinical remission. The ratios of mucosal healing at 6 and 52 weeks were 5 of 22 (22.7%) and 11 of 22 (50%), respectively. The difference in the mucosal healing ratio was significant between 6 and 52 weeks (p = 0.044). No serious adverse effects were observed during this study. CONCLUSIONS: Combination therapy with intensive GMAA and thiopurines administration rapidly induced high remission in patients with active early-diagnosed CD without serious adverse effect. Mucosal healing was observed in 50.0% of enrolled patients. This combination therapy might be a rational option for patients with early-diagnosed CD.

Predictive factors associated with the success of pneumatic dilatation in Japanese patients with primary achalasia: a study using high-resolution manometry.

BACKGROUND/AIMS: A new classification of achalasia using high-resolution manometry (HRM) has recently been suggested. Pneumatic dilatation (PD) is a common treatment for primary achalasia. The usefulness of the new classification and HRM for the treatment and follow-up of patients after PD is unknown. The aim of this study was to evaluate the PD effectiveness and the predictive factors of success in Japanese patients with achalasia using HRM and the new classification of achalasia. METHODS: Twenty-five patients were diagnosed with primary achalasia using HRM and treated by PD in our hospital. We evaluated symptom scores and esophageal manometry 6 and 12 months after the first PD. RESULTS: After the first PD treatment, remission occurred in 24 out of 25 (96.0%) patients at 6 months and in 19 out of 25 (76.0%) patients at 12 months. With the new classification of achalasia, the success rates were 83.3, 80.0 and 50% for types I, II and III, respectively, 12 months after PD. The median age of the successful group was significantly greater than that of the failure group (47.1 vs. 37.0 years, p < 0.05). The median residual lower esophageal sphincter (LES) pressure 6 months after PD in the successful group was significantly lower than that of the failure group (9.0 vs. 15.5 mm Hg, p < 0.05). CONCLUSION: Good predictors of PD success were old age (>40 years) and residual LES pressures less than 15 mm Hg 6 months after PD.

Effect of intensive granulocyte and monocyte adsorptive apheresis in patients with ulcerative colitis positive for cytomegalovirus.

BACKGROUND AND AIM: Cytomegalovirus (CMV) exacerbates ulcerative colitis (UC) refractory to immunosuppressive therapies. The conditions under which CMV reactivation occurs in patients with UC, however, is unclear. In addition, the diagnostic and treatment strategies for UC positive for CMV have not been established. Granulocyte and monocyte adsorptive apheresis (GMAA) is natural biological therapy for UC in which the granulocytes/macrophages producing inflammatory cytokines are removed. We investigated the rate of colonic CMV reactivation and the efficacy of GMAA in active UC patients positive for CMV without concomitant corticosteroid (CS) therapy. METHODS: Fifty-one active UC patients without concomitant CS therapy were enrolled. Colonic CMV reactivation was examined by real-time polymerase chain reaction (PCR) using biopsy specimen and/or histological examination. All patients were treated with intensive GMAA (twice per week). Rates of clinical remission and mucosal healing were compared between UC patients positive and negative for CMV. RESULTS: Of 51 patients, 15 (29.4%) were diagnosed as CMV positive. The clinical remission rates following intensive GMAA did not differ between UC patients positive and negative for CMV (73.3% vs 69.4%, p=0.781). Proportion of patients achieving mucosal healing was also similar between these two groups. CMV-DNA became negative in all UC patients positive for CMV who achieved clinical remission 1 week after completion of intensive GMAA. CONCLUSIONS: Intestinal inflammation might trigger CMV reactivation in a subpopulation of active UC patients without CS treatment. GMAA could be a promising option for active UC positive for CMV.

Combined pH-impedance monitoring and high-resolution manometry of Japanese patients treated with proton-pump inhibitors for persistent symptoms of non-erosive reflux disease.

BACKGROUND: Data on acid and non-acid reflux patterns and esophageal function in Japanese patients with non-erosive reflux disease (NERD) are limited. The aim of this study was to use combined multichannel intraluminal impedance pH monitoring (MII-pH) and high-resolution manometry (HRM) to investigate the characteristics of Japanese patients who were treated with a "double-dose" (20 mg) of rabeprazol (a proton-pump inhibitor; PPI) for persistent symptoms of NERD. METHODS: Twenty-five patients who complained of typical gastroesophageal reflux disease symptoms, which had occurred more than twice a week despite treatment with rabeprazol, were enrolled in the study. All patients underwent upper endoscopy, esophageal HRM, and 24-h MII-pH monitoring while double-dose PPI therapy was continued. RESULTS: Twelve (48.0%) of the patients had a positive symptom index (SI) with 234 recorded symptoms, 127 (54.3%) of which were related to reflux episodes. Of those with reflux episodes, 29 (22.8%) were related to acid reflux, while 98 (77.2%) were the result of a weaker acidic reflux. In acid reflux and in mixed (liquid-gas) reflux, the proximal esophageal region was involved to a significantly greater degree (P<0.002 and P=0.005, respectively) than the distal region. In liquid reflux, there was no difference between the distal and proximal regions. HRM showed that proximal motility parameters were significantly more defective than in those of healthy volunteers. CONCLUSIONS: MII-pH monitoring indicated that weakly acidic reflux and mixed refluxate in the proximal esophagus is the major cause of persistent symptoms in patients with NERD who are being treated with PPI. HRM showed that proximal esophageal dysfunction might be a key condition that facilitates reflux.

[A case of hepatic actinomycosis diagnosed by thin needle aspiration biopsy successfully treated with antibiotics].

A 57-year-old man presented with chief complaints of right hypochondrial pain and fever. Laboratory tests revealed severe inflammatory reactions. Abdominal ultrasonography disclosed a mass with non-homogeneous internal echoes suggesting hepatic abscess. Percutaneous liver biopsy revealed a lump of actinomycetes, allowing a diagnosis of hepatic actinomycosis. The abscess disappeared following long-term treatment with penicillin antibiotics. Actinomycosis developing primarily in the liver is very rare. This condition needs to be distinguished from tumorous lesions of the liver, including malignancy. It seems noteworthy that the diagnosis of this condition was possible on the basis of percutaneous liver biopsy.

Evolutionary computation applied to the reconstruction of 3-D surface topography in the SEM.

A genetic algorithm has been applied to the line profile reconstruction from the signals of the standard secondary electron (SE) and/or backscattered electron detectors in a scanning electron microscope. This method solves the topographical surface reconstruction problem as one of combinatorial optimization. To extend this optimization approach for three-dimensional (3-D) surface topography, this paper considers the use of a string coding where a 3-D surface topography is represented by a set of coordinates of vertices. We introduce the Delaunay triangulation, which attains the minimum roughness for any set of height data to capture the fundamental features of the surface being probed by an electron beam. With this coding, the strings are processed with a class of hybrid optimization algorithms that combine genetic algorithms and simulated annealing algorithms. Experimental results on SE images are presented.

Influence of cure of Helicobacter pylori infection on gastric acidity and gastroesophageal reflux: study by 24-h pH monitoring in patients with gastric or duodenal ulcer.

BACKGROUND: Whether or not the eradication of Helicobacter pylori is a risk factor for reflux esophagitis (RE) is a question at issue. To find an answer, it is necessary to clarify the influence of H. pylori eradication on the mechanism of RE. METHODS: The authors investigated the influence of H. pylori eradication on gastric acidity and gastroesophageal reflux in ten gastric ulcer (GU) patients and ten duodenal ulcer (DU) patients by 24-h simultaneous determination of pH in the stomach and esophagus. RESULTS: Though the results indicated enhanced gastric acidity in GU patients at night after H. pylori eradication, no such influence was observed in DU patients. No significant changes in gastroesophageal reflux occurred in GU or DU patients before and after H. pylori eradication. RE after H. pylori eradication occurred in only one patient, with GU. This patient had several risk factors for RE, such as obesity, male sex, and dietary habits to add to the increase in gastric acidity at night that occurred after H. pylori eradication. No increase in gastroesophageal reflux occurred in any DU patients or in the other GU patients that demonstrated enhanced gastric acidity at night after H. pylori eradication. CONCLUSIONS: The cure of H. pylori infection does not, by itself, cause RE in patients who have few other risk factors for RE.