Subthreshold α2-Adrenergic Activation Counteracts Glucagon-Like Peptide-1 Potentiation of Glucose-Stimulated Insulin Secretion

The pancreatic β cell harbors α2-adrenergic and glucagon-like peptide-1 (GLP-1) receptors on its plasma membrane to sense the corresponding ligands adrenaline/noradrenaline and GLP-1 to govern glucose-stimulated insulin secretion. However, it is not known whether these two signaling systems interact to gain the adequate and timely control of insulin release in response to glucose. The present work shows that the α2-adrenergic agonist clonidine concentration-dependently depresses glucose-stimulated insulin secretion from INS-1 cells. On the contrary, GLP-1 concentration-dependently potentiates insulin secretory response to glucose. Importantly, the present work reveals that subthreshold α2-adrenergic activation with clonidine counteracts GLP-1 potentiation of glucose-induced insulin secretion. This counteractory process relies on pertussis toxin- (PTX-) sensitive Gi proteins since it no longer occurs following PTX-mediated inactivation of Gi proteins. The counteraction of GLP-1 potentiation of glucose-stimulated insulin secretion by subthreshold α2-adrenergic activation is likely to serve as a molecular mechanism for the delicate regulation of insulin release

CIRNN: An Ultra-Wideband Non-Line-of-Sight Signal Classifier Based on Deep-Learning

Non-line-of-sight (NLOS) error is the main factor that reduces indoor positioning accuracy. Identifying NLOS signals and eliminating NLOS errors are the keys to improving indoor positioning accuracy. To better identify NLOS signals, a multi-stream model channel-impulse-response-neural-network (CIRNN) was proposed. The inputs of CIRNN include the channel impulse response (CIR) and a small number of channel parameters. To make a more obvious comparison between NLOS signals and line-of-sight (LOS) signals, a new energy normalization method is proposed. Fusing multi-dimensional features, the CIRNN network has a good convergence performance and shows stronger sensitivity to NLOS signals. Experimental results show that the CIRNN achieves the best accuracy on the open-source data set, the F1 score is 89.3%. At the same time, the working efficiency of CIRNN meets industry needs, CIRNN can refresh the target position at about 92.6 Hz per second

Borrelia burgdorferi elongation factor EF-Tu is an immunogenic protein during Lyme borreliosis

Borrelia burgdorferi, the etiological agent of Lyme disease, does not produce lipopolysaccharide but expresses a large number of lipoproteins on its cell surface. These outer membrane lipoproteins are highly immunogenic and have been used for serodiagnosis of Lyme disease. Recent studies have shown that highly conserved cytosolic proteins such as enolase and elongation factor Tu (EF-Tu) unexpectedly localized on the surface of bacteria including B. burgdorferi, and surface-localized enolase has shown to contribute to the enzootic cycle of B. burgdorferi. In this study, we studied the immunogenicity, surface localization, and function of B. burgdorferi EF-Tu. We found that EF-Tu is highly immunogenic in mice, and EF-Tu antibodies were readily detected in Lyme disease patients. On the other hand, active immunization studies showed that EF-Tu antibodies did not protect mice from infection when challenged with B. burgdorferi via either needle inoculation or tick bites. Borrelial mouse-tick cycle studies showed that EF-Tu antibodies also did not block B. burgdorferi migration and survival in ticks. Consistent with these findings, we found that EF-Tu primarily localizes in the protoplasmic cylinder of spirochetes and is not on the surface of B. burgdorferi. Taken together, our studies suggest that B. burgdorferi EF-Tu is not surfaced exposed, but it is highly immunogenic and is a potential serodiagnostic marker for Lyme borreliosis

GSK3β Is Involved in JNK2-Mediated β-Catenin Inhibition

We have recently reported that mitogen-activated protein kinase (MAPK) JNK1 downregulates beta-catenin signaling and plays a critical role in regulating intestinal homeostasis and in suppressing tumor formation. This study was designed to determine whether JNK2, another MAPK, has similar and/or different functions in the regulation of beta-catenin signaling.We used an in vitro system with manipulation of JNK2 and beta-catenin expression and found that activated JNK2 increased GSK3beta activity and inhibited beta-catenin expression and transcriptional activity. However, JNK2-mediated downregulation of beta-catenin was blocked by the proteasome inhibitor MG132 and GSK3beta inhibitor lithium chloride. Moreover, targeted mutations at GSK3beta phosphorylation sites (Ser33 and Ser37) of beta-catenin abrogated JNK2-mediated suppression of beta-catenin. In vivo studies further revealed that JNK2 deficiency led to upregulation of beta-catenin and increase of GSK3-beta phosphorylation in JNK2-/- mouse intestinal epithelial cells. Additionally, physical interaction and co-localization among JNK2, beta-catenin and GSK3beta were observed by immunoprecipitation, mammalian two-hybridization assay and confocal microscopy, respectively.In general, our data suggested that JNK2, like JNK1, interacts with and suppresses beta-catenin signaling in vitro and in vivo, in which GSK3beta plays a key role, although previous studies have shown distinct functions of JNK1 and JNK2. Our study also provides a novel insight into the crosstalk between Wnt/beta-catenin and MAPK JNKs signaling

Photoelectrochemical and electrochemical ratiometric aptasensing: a case study of streptomycin

There has been much interest in constructing ratiometric sensors using different sensing techniques because of their synergistic effect, although the simultaneous collection of the signals is challenging. Herein, we propose a ratiometric aptasensing strategy based on the dual-detection model with a photoelectrochemical (PEC) “signalon” and an electrochemical (EC) “signal-off”. As a proof-of-concept study, CdTe quantum dots (CdTe QDs) and a methylene blue-labeled aptamer (MB-Apt) were used to generate PEC and EC signals in the sensing system. The target-induced conformational change of MB-Apt pushed MB away from the electrode, thereby decreasing the EC signal; at the same time, the reduced steric hindrance favored the restoration of the PEC signal from the CdTe QDs. Thus, this PEC-EC strategy can achieve the PEC “signal-on” and EC “signal-off” states simultaneously, as well as allowing quantitative analysis of the target based on the ratio of the current intensities. As a model application, an aptasensor fabricated for streptomycin detection showed a wide linear range from 0.03 to 100 μM with a detection limit of 10 nM (S/N = 3). The proposed sensing platform displayed superior analytical properties compared with methods based on PEC or EC alone. Our work provides an efficient dual-detection modelbased ratiometric strategy for advanced analysis, and paves the way to the simultaneous acquisition of signals

BB0324 and BB0028 are constituents of the Borrelia burgdorferi β-barrel assembly machine (BAM) complex

<p>Abstract</p> <p>Background</p> <p>Similar to Gram-negative bacteria, the outer membrane (OM) of the pathogenic spirochete, <it>Borrelia burgdorferi</it>, contains integral OM-spanning proteins (OMPs), as well as membrane-anchored lipoproteins. Although the mechanism of OMP biogenesis is still not well-understood, recent studies have indicated that a heterooligomeric OM protein complex, known as BAM (β-barrel assembly machine) is required for proper assembly of OMPs into the bacterial OM. We previously identified and characterized the essential β-barrel OMP component of this complex in <it>B. burgdorferi</it>, which we determined to be a functional BamA ortholog.</p> <p>Results</p> <p>In the current study, we report on the identification of two additional protein components of the <it>B. burgdorferi </it>BAM complex, which were identified as putative lipoproteins encoded by ORFs BB0324 and BB0028. Biochemical assays with a BamA-depleted <it>B. burgdorferi </it>strain indicate that BB0324 and BB0028 do not readily interact with the BAM complex without the presence of BamA, suggesting that the individual <it>B. burgdorferi </it>BAM components may associate only when forming a functional BAM complex. Cellular localization assays indicate that BB0324 and BB0028 are OM-associated subsurface lipoproteins, and <it>in silico </it>analyses indicate that BB0324 is a putative BamD ortholog.</p> <p>Conclusions</p> <p>The combined data suggest that the BAM complex of <it>B. burgdorferi </it>contains unique protein constituents which differ from those found in other proteobacterial BAM complexes. The novel findings now allow for the <it>B. burgdorferi </it>BAM complex to be further studied as a model system to better our understanding of spirochetal OM biogenesis in general.</p

Histologic findings in mucosa and muscularis propria biopsied during peroral endoscopic myotomy in patients with achalasia

Background: Peroral endoscopic myotomy (POEM) has been increasingly used to treat achalasia. Previous studies have reported high frequency of muscular eosinophilic infiltration in achalasia. Esophageal mucosal changes in achalasia have only been studied in esophagectomy specimens. Cardia mucosal changes in achalasia have not been reported previously. We aimed to further characterize the esophageal, gastric cardia, and muscularis propria changes in achalasia. Methods: This was a pilot study. Patients with clinically and radiographically confirmed achalasia who underwent POEM were enrolled in the study. Mucosal biopsies were taken 1 cm proximal and 1 cm distal to the gastroesophageal junction, and muscularis propria biopsies were taken from the mid esophagus. Tissues were submitted for histological evaluation. Results: Eighteen patients (10 male and eight female, mean age: 60.7 (standard deviation (SD): 13) years) were enrolled in this pilot study. Nine patients had type II achalasia, two type III, one type I, five esophageal gastric outlet obstruction, and one unspecific type achalasia. The mean duration of symptoms prior to POEM was 79 (range 1 - 480) months. All patients had a dilated esophagus on examination, but no endoscopic evidence of Barrett\u27s esophagus. Esophageal, gastric cardia, and muscular biopsies were performed in 17, 13, and 17 patients, respectively. Basal hyperplasia, spongiosis, ballooning, and parakeratosis were seen in 92.3%, 100%, 100%, and 76.5% of cases, respectively. Intraepithelial lymphocytosis was seen in 70.5% of cases, and active esophagitis was seen in 23.5% of case. Six (35.3%) cases had few intraepithelial eosinophils, but none of them had \u3e 15 eosinophils per high power field. Histologic findings in gastric cardia mucosa included carditis (69.2%), Conclusions: Muscular biopsies in our study revealed loss of ganglion cells, supporting the view that achalasia is a primary esophageal disease with ganglion cell depletion. Squamous mucosa in achalasia showed changes mimicking reflux and lymphocytic esophagitis. Cardia mucosa in achalasia patients often were inflamed and uncommonly showed intestinal metaplasia and glandular dysplasia

Transcriptional Regulation and Biological Functions of Selenium-Binding Protein 1 in Colorectal Cancer In Vitro and in Nude Mouse Xenografts

It has been shown that selenium-binding protein 1 (SBP1) is significantly downregulated in different human cancers. Its regulation and function have not yet been established.We show that the SBP1 promoter is hypermethylated in colon cancer tissues and human colon cancer cells. Treatment with 5'-Aza-2'-deoxycytidine leads to demethylation of the SBP1 promoter and to an increase of SBP1 promoter activity, rescues SBP1 mRNA and protein expression in human colon cancer cells. Additionally, overexpression of SBP1 sensitizes colon cancer cells to H2O2-induced apoptosis, inhibits cancer cell migration in vitro and inhibits tumor growth in nude mice.These data demonstrate that SBP1 has tumor suppressor functions that are inhibited in colorectal cancer through epigenetic silencing