Repair Process Impairment by Pseudomonas aeruginosa in Epithelial Tissues: Major Features and Potential Therapeutic Avenues

Epithelial tissues protecting organs from the environment are the first-line of defense against pathogens. Therefore, efficient repair mechanisms after injury are crucial to maintain epithelial integrity. However, these healing processes can be insufficient to restore epithelial integrity, notably in infectious conditions. Pseudomonas aeruginosa infections in cutaneous, corneal, and respiratory tract epithelia are of particular concern because they are the leading causes of hospitalizations, disabilities, and deaths worldwide. Pseudomonas aeruginosa has been shown to alter repair processes, leading to chronic wounds and infections. Because of the current increase in the incidence of multi-drug resistant isolates of P. aeruginosa, complementary approaches to decrease the negative impact of these bacteria on epithelia are urgently needed. Here, we review the recent advances in the understanding of the impact of P. aeruginosa infections on the integrity and repair mechanisms of alveolar, airway, cutaneous and corneal epithelia. Potential therapeutic avenues aimed at counteracting this deleterious impact of infection are also discussed

Activation of an ATP-dependent K+ conductance in Xenopus oocytes by expression of adenylate kinase cloned from renal proximal tubules

AbstractIn rabbit proximal convoluted tubules, an ATP-sensitive K+ (KATP) channel has been shown to be involved in membrane cross-talk, i.e. the coupling (most likely mediated through intracellular ATP) between transepithelial Na+ transport and basolateral K+ conductance. This K+ conductance is inhibited by taurine. We sought to isolate this K+ channel by expression cloning in Xenopus oocytes. Injection of renal cortex mRNA into oocytes induced a K+ conductance, largely inhibited by extracellular Ba2+ and intracellular taurine. Using this functional test, we isolated from our proximal tubule cDNA library a unique clone, which induced a large K+ current which was Ba2+-, taurine- and glibenclamide-sensitive. Surprisingly, this clone is not a K+ channel but an adenylate kinase protein (AK3), known to convert NTP+AMP into NDP+ADP (N could be G, I or A). AK3 expression resulted in a large ATP decrease and activation of the whole-cell currents including a previously unknown, endogenous K+ current. To verify whether ATP decrease was responsible for the current activation, we demonstrated that inhibition of glycolysis greatly reduces oocyte ATP levels and increases an inwardly rectifying K+ current. The possible involvement of AK in the KATP channel’s regulation provides a means of explaining their observed activity in cytosolic environments characterized by high ATP concentrations

K+ channels regulate ENaC expression via changes in promoter activity and control fluid clearance in alveolar epithelial cells

AbstractActive Na+ absorption by alveolar ENaC is the main driving force of liquid clearance at birth and lung edema resorption in adulthood. We have demonstrated previously that long-term modulation of KvLQT1 and KATP K+ channel activities exerts sustained control in Na+ transport through the regulation of ENaC expression in primary alveolar type II (ATII) cells. The goal of the present study was: 1) to investigate the role of the α-ENaC promoter, transfected in the A549 alveolar cell line, in the regulation of ENaC expression by K+ channels, and 2) to determine the physiological impact of K+ channels and ENaC modulation on fluid clearance in ATII cells. KvLQT1 and KATP channels were first identified in A549 cells by PCR and Western blotting. We showed, for the first time, that KvLQT1 activation by R-L3 (applied for 24h) increased α-ENaC expression, similarly to KATP activation by pinacidil. Conversely, pharmacological KvLQT1 and KATP inhibition or silencing with siRNAs down-regulated α-ENaC expression. Furthermore, K+ channel blockers significantly decreased α-ENaC promoter activity. Our results indicated that this decrease in promoter activity could be mediated, at least in part, by the repressor activity of ERK1/2. Conversely, KvLQT1 and KATP activation dose-dependently enhanced α-ENaC promoter activity. Finally, we noted a physiological impact of changes in K+ channel functions on ERK activity, α-, β-, γ-ENaC subunit expression and fluid absorption through polarized ATII cells. In summary, our results disclose that K+ channels regulate α-ENaC expression by controlling its promoter activity and thus affect the alveolar function of fluid clearance

Evolution à court et long terme de la croissance du pin d'Alep en Provence. Conséquence sur la production de bois.

Une étude du pin d'Alep Pinus halepensis (Mill.) dans l'ouest de la Provence, a mis en évidence une accélération continue de sa vitesse de croissance en hauteur depuis plus de 10 ans. Deux modèles différents, basés d'une part sur l'analyse de tige et d'autre part sur un indice de potentialités des stations forestières, convergent vers la même estimation : un accroissement moyen de 4,5 cm/an de l'indice de fertilité pour le pin d'Alep, tous sites confondus. Cette accélération moyenne montre des inflexions, qui peuvent être reliées à des variations à court terme du climat (période > 10 ans). Parmi les causes identifiées ou supposées de l'accélération, se trouvent des changements d'usage du milieu, la remontée biologique et l'amélioration des sols, l'accroissement du taux de CO2, et les changements à long terme du climat. Dans la conclusion, on évalue les conséquences du phénomène pour la production de bois des forêts provençales de pin d'Alep

The Quebec Respiratory Health Network Biobank

The Quebec Respiratory Health Network (RHN) Biobank is a multi-site infrastructure located in the province of Quebec (Canada) to collect, store, and supply high-quality human biological specimens for research on respiratory diseases. The sample types are diverse (plasma, serum, buffy coat, primary lung cells, lung parenchyma, bronchial biopsies, polyps, others), disease-oriented, and mirror research activities conducted at each site. The biobank currently manages approximately 57,000 specimens from 8,000 research participants or patients treated by standard of care. Specimens’ inventory and corresponding clinical data from all sites are denominalized and linked to a centralized database with retrieval and querying capabilities. Archival samples from recent to nearly 20-year collections are available to academic and industry researchers studying respiratory diseases.   Funding statement: The infrastructure is supported by the Quebec Respiratory Health Network (rsr.chus.qc.ca) of the 'Fonds de la recherche du Québec – Santé' (FRQS), the research centers involved, local foundations and users of the biobank. Each biobank site is responsible to sustain their activities

Schéma stratégique et cartographie des équipements DFCI de l'Hérault.

Le Conseil général de l'Hérault a mis en uvre la réalisation du Schéma stratégique des équipements DFCI sur la base des nouvelles orientations de la Délégation à la Protection de la Forêt Méditerranéenne. L'objectif est avant tout de mettre en cohérence les équipements existants

Repair Process Impairment by Pseudomonas aeruginosa in Epithelial Tissues: Major Features and Potential Therapeutic Avenues

International audienceEpithelial tissues protecting organs from the environment are the first-line of defense against pathogens. Therefore, efficient repair mechanisms after injury are crucial to maintain epithelial integrity. However, these healing processes can be insufficient to restore epithelial integrity, notably in infectious conditions. Pseudomonas aeruginosa infections in cutaneous, corneal, and respiratory tract epithelia are of particular concern because they are the leading causes of hospitalizations, disabilities, and deaths worldwide. Pseudomonas aeruginosa has been shown to alter repair processes, leading to chronic wounds and infections. Because of the current increase in the incidence of multi-drug resistant isolates of P. aeruginosa, complementary approaches to decrease the negative impact of these bacteria on epithelia are urgently needed. Here, we review the recent advances in the understanding of the impact of P. aeruginosa infections on the integrity and repair mechanisms of alveolar, airway, cutaneous and corneal epithelia. Potential therapeutic avenues aimed at counteracting this deleterious impact of infection are also discussed

Ecopunto

Fil: Ricci Brochiero, Sofía. Universidad de San Andrés. Escuela de Negocios; Argentina.Fil: Burgwardt Rodríguez, Justina. Universidad de San Andrés. Escuela de Negocios; Argentina

Evolution à court et long terme de la croissance du pin d'Alep en Provence. Conséquence sur la production de bois.

International audienceUne étude du pin d'Alep Pinus halepensis (Mill.) dans l'ouest de la Provence, a mis en évidence une accélération continue de sa vitesse de croissance en hauteur depuis plus de 10 ans. Deux modèles différents, basés d'une part sur l'analyse de tige et d'autre part sur un indice de potentialités des stations forestières, convergent vers la même estimation : un accroissement moyen de 4,5 cm/an de l'indice de fertilité pour le pin d'Alep, tous sites confondus. Cette accélération moyenne montre des inflexions, qui peuvent être reliées à des variations à court terme du climat (période > 10 ans). Parmi les causes identifiées ou supposées de l'accélération, se trouvent des changements d'usage du milieu, la remontée biologique et l'amélioration des sols, l'accroissement du taux de CO2, et les changements à long terme du climat. Dans la conclusion, on évalue les conséquences du phénomène pour la production de bois des forêts provençales de pin d'Alep