234 research outputs found
Ablation of aquaporinâ9 ameliorates the systemic inflammatory response of lpsâinduced endotoxic shock in mouse
Septic shock is the most severe complication of sepsis, being characterized by a systemic inflammatory response following bacterial infection, leading to multiple organ failure and dra-matically high mortality. Aquaporinâ9 (AQP9), a membrane channel protein mainly expressed in hepatocytes and leukocytes, has been recently associated with inflammatory and infectious re-sponses, thus triggering strong interest as a potential target for reducing septic shockâdependent mortality. Here, we evaluated whether AQP9 contributes to murine systemic inflammation during endotoxic shock. Wild type (Aqp9+/+; WT) and Aqp9 gene knockout (Aqp9â/â; KO) male mice were submitted to endotoxic shock by i.p. injection of lipopolysaccharide (LPS; 40 mg/kg) and the related survival times were followed during 72 h. The electronic paramagnetic resonance and confocal microscopy were employed to analyze the nitric oxide (NO) and superoxide anion (O2â) produc-tion, and the expression of inducible NOâsynthase (iNOS) and cyclooxigenaseâ2 (COXâ2), respec-tively, in the liver, kidney, aorta, heart and lung of the mouse specimens. LPSâtreated KO mice survived significantly longer than corresponding WT mice, and 25% of the KO mice fully recov-ered from the endotoxin treatment. The LPSâinjected KO mice showed lower inflammatory NO and O2â productions and reduced iNOS and COXâ2 levels through impaired NFâÎșB p65 activation in the liver, kidney, aorta, and heart as compared to the LPSâtreated WT mice. Consistent with these results, the treatment of FaO cells, a rodent hepatoma cell line, with the AQP9 blocker HTS13268 prevented the LPSâinduced increase of inflammatory NO and O2â. A role for AQP9 is suggested in the early acute phase of LPSâinduced endotoxic shock involving NFâÎșB signaling. The modulation of AQP9 expression/function may reveal to be useful in developing novel endotoxemia therapeutic
Integrated approach of RUSLE, GIS and ESA Sentinel-2 satellite data for post-fire soil erosion assessment in Basilicata region (Southern Italy)
Fire effects consist not only in direct damage to the vegetation but also in the modification of both chemical and physical soil properties. Fire can affect the alteration of soil properties in different ways depending on fire severity and soil type. The most important consequences concern changes in soil responsiveness to the water action and the subsequent increase in sediment transport and erosion. Post fire soil loss can increase in the first year by several orders of magnitude compared to pre-fire erosion. In this study a distributed model based on the Revised Universal Soil Loss Equation (RUSLE) is used to estimate potential post-fire soil loss for four different fire events occurred in Basilicata region in 2017. Geographic Information System techniques and remote sensing data have been adopted to build a prediction model of post-fire soil erosion risk. Results show that this model is not only able to quantify post-fire soil loss but also to identify the complexity of the relationships between fire severity and all the factors that influence soil susceptibility to erosion
Stopped-flow Light Scattering Analysis of Red Blood Cell Glycerol Permeability
Stopped-Flow Light Scattering (SFLS) is a method devised to analyze the kinetics of fast chemical reactions that result in a significant change of the average molecular weight and/or in the shape of the reaction substrates. Several modifications of the original stopped-flow system have been made leading to a significant extension of its technical applications. One of these modifications allows the biophysical characterization of the water and solute permeability of biological and artificial membranes.Here, we describe a protocol of SFLS to measure the glycerol permeability of isolated human red blood cells (RBCs) and evaluate the pharmacokinetics properties (selectivity and potency) of isoform-specific inhibitors of AQP3, AQP7 and AQP9, three mammalian aquaglyceroporins allowing transport of glycerol across membranes. Suspensions of RBCs (1% hematocrit) are exposed to an inwardly directed gradient of 100 mM glycerol in a SFLS apparatus at 20 degrees C and the resulting changes in scattered light intensity are recorded at a monochromatic wavelength of 530 nm for 120 s. The SFLS apparatus is set up to have a dead time of 1.6-ms and 99% mixing efficiency in less than 1 ms. Data are fitted to a single exponential function and the related time constant (tau, seconds) of the cell-swelling phase of light scattering corresponding to the osmotic movement of water that accompanies the entry of glycerol into erythrocytes is measured. The coefficient of glycerol permeability (P-gly, cm/s) of RBCs is calculated with the following equation:P-gly = 1/[(S/V)tau]where tau (s) is the fitted exponential time constant and S/V is the surface-to-volume ratio (cm(-1)) of the analyzed RBC specimen. Pharmacokinetics of the isoform-specific inhibitors of AQP3, AQP7 and AQP9 are assessed by evaluating the extent of RBC P-gly values resulting after the exposure to serial concentrations of the blockers
The inner mitochondrial membrane has aquaporin-8 water channels and is highly permeable to water.
International audience; Mitochondria are remarkably plastic organelles constantly changing their shape to fulfil their various functional activities. Although the osmotic movement of water into and out of the mitochondrion is central for its morphology and activity, the molecular mechanisms and the pathways for water transport across the inner mitochondrial membrane (IMM), the main barrier for molecules moving into and out of the organelle, are completely unknown. Here, we show the presence of a member of the aquaporin family of water channels, AQP8, and demonstrate the strikingly high water permeability (Pf) characterizing the rat liver IMM. Immunoblotting, electron microscopy, and biophysical studies show that the largest mitochondria feature the highest AQP8 expression and IMM Pf. AQP8 was also found in the mitochondria of other organs, whereas no other known aquaporins were seen. The osmotic water transport of liver IMM was partially inhibited by the aquaporin blocker Hg2+, while the related activation energy remained low, suggesting the presence of a Hg2+-insensitive facilitated pathway in addition to AQP8. It is suggested that AQP8-mediated water transport may be particularly important for rapid expansions of mitochondrial volume such as those occurring during active oxidative phosphorylation and those following apoptotic signals
Towards specific TâH relationships: FRIBAS database for better characterization of RC and URM buildings
FRIBAS database is an open access database (https://doi.org/10.5281/zenodo.6505442) composed of the characteristics of 312 buildings (71 masonry, 237 reinforced concrete and 4 mixed types). It collects and harmonizes data from different surveys performed on buildings in the Basilicata and Friuli Venezia Giulia regions (Southern and Northeastern Italy, respectively). Each building is defined by 37 parameters related to the building and foundation soil characteristics. The building and soil fundamental periods were experimentally estimated based on ambient noise measurements. FRIBAS gave us the opportunity to study the influence of the main characteristics of buildings and the soil-building interaction effect to their structural response. In this study, we have used the FRIBAS dataset to investigate how the building period varies as a function of construction materials and soil types. Our results motivate the need of going beyond a âone-fits-allâ numerical periodâheight (TâH) relationship for generic building typologies provided by seismic codes, towards specific TâH relationships that account for both soil and building typologies
Genistein and 17ÎČ-Estradiol Protect Hepatocytes from Fatty Degeneration by Mechanisms Involving Mitochondria, Inflammasome and Kinases Activation
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Finding aquaporins in annelids : An evolutionary analysis and a case study
Funding Information: This research was funded by PRIN2017 Programmi di Ricerca Scientifica di Rilevante Interesse Nazionale 2017 (grant # 2017J92TM5) by Italian MUR to G.C. and by the Molecular Bio-diversity Laboratory of the Italian node of Lifewatch (CNR, Consiglio Nazionale delle Ricerche) to C.G.Peer reviewedPublisher PD
Exposure to Plasma From Non-alcoholic Fatty Liver Disease Patients Affects Hepatocyte Viability, Generates Mitochondrial Dysfunction, and Modulates Pathways Involved in Fat Accumulation and Inflammation
Changes of lipidic storage, oxidative stress and mitochondrial dysfunction may be involved in the pathogenesis of non-alcoholic fatty liver disease (NAFLD). Although the knowledge of intracellular pathways has vastly expanded in recent years, the role and mechanisms of circulating triggering factor(s) are debated. Thus, we tested the hypothesis that factors circulating in the blood of NAFLD patients may influence processes underlying the disease. Huh7.5 cells/primary human hepatocytes were exposed to plasma from 12 NAFLD patients and 12 healthy subjects and specific assays were performed to examine viability, H2O2 and mitochondrial reactive oxygen species (ROS) release, mitochondrial membrane potential and triglycerides content. The involvement of NLRP3 inflammasome and of signaling related to peroxisome-proliferator-activating-ligand-receptor-\u3b3 (PPAR\u3b3), sterol-regulatory-element-binding-protein-1c (SREBP-1c), nuclear-factor-kappa-light-chain-enhancer of activated B cells (NF-kB), and NADPH oxidase 2 (NOX2) was evaluated by repeating the experiments in the presence of NLRP3 inflammasome blocker, MCC950, and through Western blot. The results obtained shown that plasma of NAFLD patients was able to reduce cell viability and mitochondrial membrane potential by about 48 and 24% (p < 0.05), and to increase H2O2, mitochondrial ROS, and triglycerides content by about 42, 19, and 16% (p < 0.05), respectively. An increased expression of SREBP-1c, PPAR\u3b3, NF-kB and NOX2 of about 51, 121, 63, and 46%, respectively, was observed (p < 0.05), as well. Those effects were reduced by the use of MCC950. Thus, in hepatocytes, exposure to plasma from NAFLD patients induces a NAFLD-like phenotype by interference with NLRP3-inflammasome pathways and the activation of intracellular signaling related to SREBP-1c, PPAR\u3b3, NF-kB and NOX2
Regulation of the Escherichia coli water channel gene aqpZ
Osmotic movement of water across bacterial cell membranes is postulated to be a homeostatic mechanism for maintaining cell turgor. The molecular water transporter remained elusive until discovery of the Escherichia coli water channel, AqpZ, however the regulation of the aqpZ gene expression and physiological function of the AqpZ protein are unknown. Northern analysis revealed a transcript of 0.7 kb, confirming the monocistronic nature of aqpZ. Regulatory studies performed with an aqpZ::lacZ low copy plasmid demonstrate enhanced expression during mid-logarithmic growth, and expression of the gene is dependent upon the extracellular osmolality, which increased in hypoosmotic environments but strongly reduced in hyperosmolar NaCl or KCl. While disruption of the chromosomal aqpZ is not lethal for E. coli, the colonies of the aqpZ knockout mutant are smaller than those of the parental wild-type strain. When cocultured with parental wild-type E. coli, the aqpZ knockout mutant exhibits markedly reduced colony formation when grown at 39 degrees C. Similarly, the aqpZ knockout mutant also exhibits greatly reduced colony formation when grown at low osmolality, but this phenotype is reversed by overexpression of AqpZ protein. These results implicate AqpZ as a participant in the adaptive response of E. coli to hypoosmotic environments and indicate a requirement for AqpZ by rapidly growing cells
Gallbladder histopathology during murine gallstone formation: Relation to motility and concentrating function
C57L mice are susceptible and AKR mice are resistant to gallstone formation. We studied in male mice of both strains gallbladder histopathology, cholecystokinin-induced emptying, and concentrating function at 0, 14, 28, and 56 days on a lithogenic diet. Gallbladder wall thickness increased on the diet, with stromal granulocyte infiltration, progressive fibrosis, edema, and epithelial cell indentation, particularly in C57L. Strong basal cholecystokinin octapeptide-induced gallbladder emptying (70% of fasting volumes) occurred in both strains, but fasting gallbladder volumes were significantly larger in C57L (14.8 +/- 2.2 microl vs. 8.8 +/- 1.0 microl). On the diet, fasting volumes increased exclusively in C57L (28.6 +/- 2.9 microl on day 56), with progressively decreased emptying (27% of fasting volumes on day 56). Gallbladder emptying remained normal in AKR. Gallbladder concentrating function decreased on the lithogenic diet (especially in C57L), coinciding with decreased aquaporin-1 (AQP1) and AQP8 expression at the mRNA and protein levels. In additional experiments, similar downregulation of AQP1 and AQP8 mRNA expression occurred in farnesoid X receptor (FXR)-deficient mice after 1 week on the lithogenic diet, without any difference from corresponding wild-type mice. In conclusion, during murine lithogenesis, altered gallbladder histology is associated with impaired motility, reduced concentrating function, and decreased AQP1 and AQP8 expression, the latter without the involvement of the FXR
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