Consequences of replacing EGFR juxtamembrane domain with an unstructured sequence.

PMC3497011EGFR is the best studied receptor tyrosine kinase. Yet, a comprehensive mechanistic understanding of EGFR signaling is lacking, despite very active research in the field. In this paper, we investigate the role of the juxtamembrane (JM) domain in EGFR signaling by replacing it with a (GGS)(10) unstructured sequence. We probe the effect of this replacement on (i) EGFR phosphorylation, (ii) EGFR dimerization and (iii) ligand (EGF) binding. We show that the replacement of EGFR JM domain with a (GGS)(10) unstructured linker completely abolishes the phosphorylation of all tyrosine residues, without measurable effects on receptor dimerization or ligand binding. Our results suggest that the JM domain does not stabilize the inactive EGFR dimer in the absence of ligand, and is likely critical only for the last step of EGFR activation, the ligand-induced transition from the inactive to active dimer.JH Libraries Open Access Fun

The Rho exchange factor Arhgef1 mediates the effects of angiotensin II on vascular tone and blood pressure

Hypertension is one of the most frequent pathologies in the industrialized world. Although recognized to be dependent on a combination of genetic and environmental factors, its molecular basis remains elusive. Increased activity of the monomeric G protein RhoA in arteries is a common feature of hypertension. However, how RhoA is activated and whether it has a causative role in hypertension remains unclear. Here we provide evidence that Arhgef1 is the RhoA guanine exchange factor specifically responsible for angiotensin II-induced activation of RhoA signaling in arterial smooth muscle cells. We found that angiotensin II activates Arhgef1 through a previously undescribed mechanism in which Jak2 phosphorylates Tyr738 of Arhgef1. Arhgef1 inactivation in smooth muscle induced resistance to angiotensin II-dependent hypertension in mice, but did not affect normal blood pressure regulation. Our results show that control of RhoA signaling through Arhgef1 is central to the development of angiotensin II-dependent hypertension and identify Arhgef1 as a potential target for the treatment of hypertension

Does Adherence to the Mediterranean Diet Have a Protective Effect against Asthma and Allergies in Children? A Systematic Review

Dietary pattern may potentially impact on the pathogenesis of asthma and allergies. The Mediterranean Diet (MD) has significant health benefits due to its antioxidant and anti-inflammatory properties. The aim of this systematic review was to investigate the effectiveness of adherence to the MD against asthma and allergies in childhood. Hence, a systematic literature search was conducted on PubMed, ESBCO (Cinahl), Scopus, and the Cochrane Library databases up to 26 January 2022. The total number of articles obtained, after the initial search on the databases was conducted, was 301. Twelve studies were included, after the removal of duplicates and screening for eligibility. Our findings indicated a protective role of the MD against childhood asthma, but they also imply that the MD probably does not affect the development of allergies. Nevertheless, the heterogeneity and limitations of the studies highlight the need for randomized controlled trials that will focus on the pediatric population and hopefully provide more robust evidence

Does Adherence to the Mediterranean Diet Have a Protective Effect against Asthma and Allergies in Children? A Systematic Review

Dietary pattern may potentially impact on the pathogenesis of asthma and allergies. The Mediterranean Diet (MD) has significant health benefits due to its antioxidant and anti-inflammatory properties. The aim of this systematic review was to investigate the effectiveness of adherence to the MD against asthma and allergies in childhood. Hence, a systematic literature search was conducted on PubMed, ESBCO (Cinahl), Scopus, and the Cochrane Library databases up to 26 January 2022. The total number of articles obtained, after the initial search on the databases was conducted, was 301. Twelve studies were included, after the removal of duplicates and screening for eligibility. Our findings indicated a protective role of the MD against childhood asthma, but they also imply that the MD probably does not affect the development of allergies. Nevertheless, the heterogeneity and limitations of the studies highlight the need for randomized controlled trials that will focus on the pediatric population and hopefully provide more robust evidence.</jats:p

Identification of ADAMTS13 Epitopes Required for Binding to von Willebrand Factor Using Lambda Phage Surface Display.

Abstract The metalloprotease ADAMTS13 cleaves multimeric von Willebrand factor (VWF) to regulate VWF-mediated thrombus formation. We planned to search core epitopes of ADAMTS13 that is required for its binding to VWF. We constructed a random cDNA fragment library expressing various peptides of ADAMTS13 on the surface of lambda phage and screened the library using immobilized VWF as a probe. After the first screening, the C-terminus of the spacer domain from Arg670 to Glu684 (termed as epitope-1) and the middle of the cysteine-rich domain from Arg484 to Arg507 (epitope-2) were determined as epitopes. When we added the synthetic epitope-1 peptide to the second screening, a new site, from Pro618 to Glu641 (epitope-3), was found in the middle of spacer domain. While the presence of synthetic epitope-2 peptide did not affect the subsequent screening, the presence of epitope-3 peptide enhanced the isolation of clones encoding epitope-1. These results suggest that ADAMTS13 epitopes-1, -2 and -3 may interact with each other for their binding to VWF. From screening in the presence of any combination or all of the three synthetic peptides, however, no new VWF binding site was uncovered. To examine the effect of divalent metal cations on the binding of ADAMTS13 epitopes to immobilized VWF, screening was carried out in the presence or absence of 5 mM of EDTA. No new epitope site was found. We next explored inhibitory effect of the synthetic epitope peptides on ADAMTS13 protease activity using recombinant ADAMTS13 and FRETS-VWF73 as a substrate. Synthetic epitopes-2 and -3 peptides markedly inhibited the cleavage of VWF by ADAMTS13, while the synthetic epitope-1 peptide did not as efficiently as epitopes-2 and -3. The stronger inhibitory effect of epitope-3 peptide than that of epitope-1 peptide was confirmed by SDS-agarose gel electrophoresis analysis of cleavage products of denatured multimeric VWF molecules by recombinant ADAMTS13. This was consistent with the dissociation constants for the three synthetic peptides with immobilized VWF determined by surface plasmon resonance, in which epitopes-2 and -3 have higher affinities for VWF than that of epitope-1. The results described above suggest that ADAMTS13 may initially bind to immobilized VWF through the sites of epitope-1 and epitope-2 with relatively weak affinity. The binding of epitope-1 to VWF may subsequently induce the conformational change of VWF, thereby exposing a binding site for epitope-3 for the efficient catalytic cleavage of VWF by ADAMTS13.</jats:p

The Association between CFTR Gene Mutation Heterozygosity and Asthma Development: A Systematic Review

Asthma is caused by complex interactions between environmental and genetic factors. Various genes have been implicated as potential risk factors in the development of asthma; among them is cystic fibrosis transmembrane conductance regulator (CFTR) gene. The aim of this systematic review was to investigate the association of CFTR mutation heterozygosity with the development of asthma, by updating the existing data with recent studies&rsquo; findings. Therefore, a systematic review of the literature was conducted on Pubmed, ESBCO (Cinahl) and Scopus Databases up to December 2022. After the eligibility assessment, 17 studies were included in this review. Nine of them supported a lack of relationship between CFTR mutation heterozygosity and asthma susceptibility, and eight reported a positive association. Consequently, more extensive research is needed through high-quality studies to provide valid evidence and highlight the clinical benefits of identifying CFTR mutations in asthma patients, their impact on asthma severity, or treatment perspectives

Asthma-Like Features and Anti-Asthmatic Drug Prescription in Children with Non-CF Bronchiectasis

Bronchiectasis and asthma may share some characteristics and some patients may have both conditions. The present study aimed to examine the rationale of prophylactic inhaled corticosteroids (ICS) prescription in children with bronchiectasis. Data of children with radiologically established bronchiectasis were retrospectively reviewed. Episodes of dyspnea and wheezing, spirometric indices, total serum IgE, blood eosinophil counts, sensitization to aeroallergens, and air-trapping on expiratory CT scans, were recorded. The study included 65 children 1.5–16 years old, with non-CF bronchiectasis. Episodes of dyspnea or wheezing were reported by 22 (33.8%) and 23 (35.4%), respectively. Skin prick tests to aeroallergens (SPTs) were positive in 15 (23.0%) patients. Mosaic pattern on CT scans was observed in 37 (56.9%) patients. Dyspnea, presence of mosaic pattern, positive reversibility test, and positive SPTs were significantly correlated with the prescription of ICS. The prescription of ICS in children with bronchiectasis is more likely when there are certain asthma-like characteristics. The difficulty to set the diagnosis of real asthma in cases of bronchiectasis may justify the decision of clinicians to start an empirical trial with ICS in certain cases.</jats:p