A Novel Role for Aquaporin-5 in Enhancing Microtubule Organization and Stability

Abstract Aquaporin-5 (AQP5) is a water-specific channel located on the apical surface of airway epithelial cells. In addition to regulating transcellular water permeability, AQP5 can regulate paracellular permeability, though the mechanisms by which this occurs have not been determined. Microtubules also regulate paracellular permeability. Here, we report that AQP5 promotes microtubule assembly and helps maintain the assembled microtubule steady state levels with slower turnover dynamics in cells. Specifically, reduced levels of AQP5 correlated with lower levels of assembled microtubules and decreased paracellular permeability. In contrast, overexpression of AQP5 increased assembly of microtubules, with evidence of increased MT stability, and promoted the formation of long straight microtubules in the apical domain of the epithelial cells. These findings indicate that AQP5-mediated regulation of microtubule dynamics modulates airway epithelial barrier properties and epithelial function

A Novel Role for Aquaporin-5 in Enhancing Microtubule Organization and Stability

Aquaporin-5 (AQP5) is a water-specific channel located on the apical surface of airway epithelial cells. In addition to regulating transcellular water permeability, AQP5 can regulate paracellular permeability, though the mechanisms by which this occurs have not been determined. Microtubules also regulate paracellular permeability. Here, we report that AQP5 promotes microtubule assembly and helps maintain the assembled microtubule steady state levels with slower turnover dynamics in cells. Specifically, reduced levels of AQP5 correlated with lower levels of assembled microtubules and decreased paracellular permeability. In contrast, overexpression of AQP5 increased assembly of microtubules, with evidence of increased MT stability, and promoted the formation of long straight microtubules in the apical domain of the epithelial cells. These findings indicate that AQP5-mediated regulation of microtubule dynamics modulates airway epithelial barrier properties and epithelial function

Regulatory T cells reduce acute lung injury fibroproliferation by decreasing fibrocyte recruitment

Acute lung injury (ALI) causes significant morbidity and mortality. Fibroproliferation in ALI results in worse outcomes, but the mechanisms governing fibroproliferation remain poorly understood. Regulatory T cells (Tregs) are important in lung injury resolution. Their role in fibroproliferation is unknown. We sought to identify the role of Tregs in ALI fibroproliferation, using a murine model of lung injury. Wild-type (WT) and lymphocyte-deficient Rag-1-/- mice received intratracheal LPS. Fibroproliferationwascharacterizedby histology and the measurement of lung collagen. Lung fibrocytes were measured by flow cytometry. To dissect the role of Tregs in fibroproliferation, Rag-1-/- mice received CD4 +CD25+ (Tregs) or CD4+ CD25- Tcells (non-Tregs) at the time of LPS injury. To define the role of the chemokine (C-X-C motif) ligand 12 (CXCL12)-CXCR4 pathway in ALI fibroproliferation, Rag-1-/- mice were treated with the CXCR4 antagonist AMD3100 to block fibrocyte recruitment. WT and Rag-1-/- mice demonstrated significant collagen deposition on Day 3 after LPS. WT mice exhibited the clearance of collagen, but Rag-1-/- mice developed persistent fibrosis. This fibrosis was mediated by the sustained epithelial expression of CXCL12 (or stromal cell-derived factor 1 [SDF-1]) that led to increased fibrocyte recruitment. The adoptive transfer of Tregs resolved fibroproliferation by decreasing CXCL12 expression and subsequent fibrocyte recruitment. Blockade of the CXCL12-CXCR4 axis with AMD3100 also decreased lung fibrocytes and fibroproliferation. These results indicate a central role for Tregs in the resolution of ALI fibroproliferation by reducing fibrocyte recruitment along the CXCL12-CXCR4 axis. A dissection of the role of Tregs in ALI fibroproliferation may inform the design of new therapeutic tools for patients with ALI

Aquaporin 5 Polymorphisms and Rate of Lung Function Decline in Chronic Obstructive Pulmonary Disease

RATIONALE: Aquaporin-5 (AQP5) can cause mucus overproduction and lower lung function. Genetic variants in the AQP5 gene might be associated with rate of lung function decline in chronic obstructive pulmonary disease (COPD). METHODS: Five single nucleotide polymorphisms (SNPs) in AQP5 were genotyped in 429 European American individuals with COPD randomly selected from the NHLBI Lung Health Study. Mean annual decline in FEV(1) % predicted, assessed over five years, was calculated as a linear regression slope, adjusting for potential covariates and stratified by smoking status. Constructs containing the wildtype allele and risk allele of the coding SNP N228K were generated using site-directed mutagenesis, and transfected into HBE-16 (human bronchial epithelial cell line). AQP5 abundance and localization were assessed by immunoblots and confocal immunofluorescence under control, shear stress and cigarette smoke extract (CSE 10%) exposed conditions to test for differential expression or localization. RESULTS: Among continuous smokers, three of the five SNPs tested showed significant associations (0.02>P>0.004) with rate of lung function decline; no associations were observed among the group of intermittent or former smokers. Haplotype tests revealed multiple association signals (0.012>P>0.0008) consistent with the single-SNP results. In HBE16 cells, shear stress and CSE led to a decrease in AQP5 abundance in the wild-type, but not in the N228K AQP5 plasmid. CONCLUSIONS: Polymorphisms in AQP5 were associated with rate of lung function decline in continuous smokers with COPD. A missense mutation modulates AQP-5 expression in response to cigarette smoke extract and shear stress. These results suggest that AQP5 may be an important candidate gene for COPD

Macrophage A2A adenosinergic receptor modulates oxygen-induced augmentation of murine lung injury

Acute respiratory distress syndrome (ARDS) causes significant morbidity and mortality. Exacerbating factors increasing the risk of ARDS remain unknown. Supplemental oxygen is oftennecessary inbothmild and severe lung disease. The potential effects of supplemental oxygen may include augmentation of lung inflammation by inhibiting antiinflammatory pathways in alveolar macrophages. We sought to determine oxygen- derived effects on the anti-inflammatory A2A adenosinergic (ADORA2A) receptor in macrophages, and the role of the ADORA2A receptor in lung injury. Wild-type (WT) and ADORA2A-/- mice received intratracheal lipopolysaccharide (IT LPS), followed 12 hours later by continuous exposure to 21% oxygen (control mice) or 60% oxygenfor1to3days. Wemeasuredthephenotypic endpoints of lung injury and the alveolarmacrophage inflammatory state.We tested an ADORA2A-specific agonist, CGS-21680 hydrochloride, in LPS plus oxygen-exposed WT and ADORA2A-/- mice. We determined the specific effects of myeloid ADORA2A, using chimera experiments. Compared with WT mice, ADORA2A-/- mice exposed to IT LPS and 60%oxygen demonstrated significantly more histologic lung injury, alveolar neutrophils, and protein. Macrophages from ADORA2A-/- mice exposedto LPS plus oxygen expressed higher concentrations of proinflammatory cytokines and cosignaling molecules. CGS- 21680 prevented the oxygen-induced augmentation of lung injury after LPS only in WT mice. Chimera experiments demonstrated that the transfer of WT but not ADORA2A-/- bone marrow cells into irradiated ADORA2A-/- mice reduced lung injury after LPS plus oxygen, demonstrating myeloid ADORA2A protection. ADORA2A is protective against lung injury after LPS and oxygen. Oxygen after LPS increases macrophage activation to augment lung injury by inhibiting the ADORA2A pathway

Chemical investigation of some Indian plants. Part VI

Several known compounds belonging to the class of acids, alcohols, alkaloids, anthraquinones, carbohydrates, coumarins, isocoumarins, steroids, triterpenoids and xanthones have been isolated from a number of Indian plants

A morphogenetic EphB/EphrinB code controls hepatopancreatic duct formation

© 2019 The Authors. Published by Springer. This is an open access article available under a Creative Commons licence. The published version can be accessed at the following link on the publisher’s website: https://doi.org/10.1038/s41467-019-13149-7The hepatopancreatic ductal (HPD) system connects the intrahepatic and intrapancreatic ducts to the intestine and ensures the afferent transport of the bile and pancreatic enzymes. Yet the molecular and cellular mechanisms controlling their differentiation and morphogenesis into a functional ductal system are poorly understood. Here, we characterize HPD system morphogenesis by high-resolution microscopy in zebrafish. The HPD system differentiates from a rod of unpolarized cells into mature ducts by de novo lumen formation in a dynamic multi-step process. The remodeling step from multiple nascent lumina into a single lumen requires active cell intercalation and myosin contractility. We identify key functions for EphB/EphrinB signaling in this dynamic remodeling step. Two EphrinB ligands, EphrinB1 and EphrinB2a, and two EphB receptors, EphB3b and EphB4a, control HPD morphogenesis by remodeling individual ductal compartments, and thereby coordinate the morphogenesis of this multi-compartment ductal system.This work was funded by the Novo Nordisk Foundation (NNF17CC0027852) and Danish National Research Foundation (DNRF116). J.C. and D.G.W. were supported by the Francis Crick Institute, which receives its core funding from Cancer Research UK (FC001217), the UK Medical Research Council (FC001217), and the Wellcome Trust (FC001217). S.C. was supported by an SNSF Early Postdoc Mobility fellowship (P2ZHP3_164840) and a Long Term EMBO Postdoc fellowship (ALTF 511-2016), and L.S. and J.B.A. by the Independent Research Fund Denmark (DFF; Sapere Aude2 4183-00118B).Published versio

Many manifestations of digestive ripening: monodispersity, superlattices and nanomachining

Digestive ripening has now been established as a very convenient route to obtain monodisperse nanoparticles from polydisperse ones by refluxing the latter in the presence of an excess ligand. Many ligands including long chain thiols, amines, or phosphines have been shown to be effective digestive ripening agents. It is hypothesized that the surface active groups of such digestive ripening agents bind and remove reactive surface atoms/clusters from big nanoparticles and redeposit them on smaller nanoparticles. In this way, large particles become smaller, while small particles become larger, and eventually, an equilibrium size is obtained that is specific to each of the digestive ripening agents used. Herein, the digestive ripening procedure is reviewed, discussed and its utility spanning the preparation of monodispersed metal nanoparticles, alloy nanoparticles, superlattice structures and the most interesting nano-machining (wherein the monodisperse particles can be reverted back to the polydisperse system) is demonstrated

Melting characteristics of superlattices of alkanethiol-capped gold nanoparticles: the “excluded” story of excess thiol

Melting characteristics of gold nanoparticle superlattices obtained from nanoparticles capped by alkanethiols of different chain lengths (octane, dodecane and hexadecane) have been investigated. The alkanethiol capped nanoparticles were synthesized by the well-established digestive ripening method. It is observed that as the chain length of the thiol increases, the propensity to form superlattices decreases and the melting of the superlattice is observed at lower temperature. However, the formation of the 3D superlattice is critically dependent on the presence of “excess” thiol as determined from thermogravimetric and transmission electron microscope analysis. In the absence of “excess” thiol, only 2D hexagonally close-packed arrangements were seen