Temporal Dynamics of Intranasal Oxytocin in Human Brain Electrophysiology.

Oxytocin (OT) is a key modulator of human social cognition, popular in behavioral neuroscience. To adequately design and interpret intranasal OT (IN-OT) research, it is crucial to know for how long it affects human brain function once administered. However, this has been mostly deduced from peripheral body fluids studies, or uncommonly used dosages.

Bioelectric and Morphological Response of Liquid-Covered Human Airway Epithelial Calu-3 Cell Monolayer to Periodic Deposition of Colloidal 3-Mercaptopropionic-Acid Coated CdSe-CdS/ZnS Core-Multishell Quantum Dots.

Lung epithelial cells are extensively exposed to nanoparticles present in the modern urban environment. Nanoparticles, including colloidal quantum dots (QDs), are also considered to be potentially useful carriers for the delivery of drugs into the body. It is therefore important to understand the ways of distribution and the effects of the various types of nanoparticles in the lung epithelium.

Protein kinase A directly phosphorylates metabotropic glutamate receptor 5 to modulate its function.

Metabotropic glutamate receptor 5 (mGluR5) regulates excitatory post-synaptic signaling in the central nervous system (CNS) and is implicated in various CNS disorders. Protein kinase A (PKA) signaling is known to play a critical role in neuropsychiatric disorders such as Parkinson's disease, schizophrenia, and addiction. Dopamine signaling is known to modulate the properties of mGluR5 in a cAMP- and PKA-dependent manner, suggesting that mGluR5 may be a direct target for PKA.

Development of a novel microfluidic device for long-term in situ monitoring of live cells in 3-dimensional matrices.

Using the latest innovations in microfabrication technology, 3-dimensional microfluidic cell culture systems have been developed as an attractive alternative to traditional 2-dimensional culturing systems as a model for long-term microscale cell-based research. Most microfluidic systems are based on the embedding of cells in hydrogels. However, physiologically realistic conditions based on hydrogels are difficult to obtain and the systems are often too complicated.

Urinary aquaporin-2 excretion during ibuprofen or indomethacin treatment in preterm infants with patent ductus arteriosus.

Aim: Water channel AQP2 is the target for vasopressin (AVP) and a major determinant of urinary concentrating capacity. In mature kidneys, prostaglandins counteract the effect of AVP on AQP2 expression at functional sites. We investigated whether disturbances in water homeostasis in infants with patent ductus arteriosus (PDA) treated with prostaglandin inhibitors can be attributed to activation of AQP2.

Low pulmonary expression of epithelial Na(+) channel and Na(+), K(+)-ATPase in newborn infants with congenital diaphragmatic hernia.

Background: It has been suggested from several animal studies and clinical observations that congenital diaphragmatic hernia (CDH) with pulmonary hypoplasia is accompanied by a disturbed perinatal ion transport. This could lead to respiratory distress due to slower clearance of fetal lung fluid at birth.

Objectives: The purpose of this study was to determine whether CDH is related to changes in the expression of three rate-limiting transporter proteins in lung epithelium at birth.

The renal adverse effects of ibuprofen are not mediated by AQP2 water channels.

The aim of this study was to determine (1) whether ibuprofen treatment in very preterm infants causes an increase in the renal water channel aquaporin-2 (AQP2) activity in the collecting duct via prostaglandin synthesis inhibition and (2) whether AQP2 activity remains disturbed long after ibuprofen treatment has ended. This was a prospective study involving premature infants with a gestation age of 27-31 weeks who received treatment between December 2005 and August 2006 in a tertiary Neonatal Intensive Care Unit. Each ibuprofen-treated infant was matched to two controls.

Regulation of brain aquaporins.

Three aquaporins are expressed in the brain. AQP4, the predominant brain water channel, is expressed in astrocyte endfeet facing brain capillaries, perisynaptic spaces, and nodes of Ranvier. It is implicated in brain edema formation and resolution.

Differential water permeability and regulation of three aquaporin 4 isoforms.

Aquaporin 4 (AQP4) is expressed in the perivascular glial endfeet and is an important pathway for water during formation and resolution of brain edema. In this study, we examined the functional properties and relative unit water permeability of three functional isoforms of AQP4 expressed in the brain (M1, M23, Mz). The M23 isoform gave rise to square arrays when expressed in Xenopus laevis oocytes.

Expression of water and ion transporters in tracheal aspirates from neonates with respiratory distress.

Aim: The aim of the study was to determine whether neonatal respiratory distress is related to changes in water and ion transporter expression in lung epithelium.

Methods: The study included 32 neonates on mechanical ventilation: 6 patients with normal lung X-rays (control group), eight with respiratory distress syndrome (RDS), eight with transient tachypnea of the newborn (TTN), 10 with abnormal lung X-rays (mixed group). The protein abundance of water channel AQP5, epithelial sodium channel (ENaC; alpha-, beta- and gamma-ENaC) and Na(+), K(+)-ATPase alpha1 were examined in tracheal aspirates using semiquantitative immunoblotting.

Expression of chloride channels in trachea-occluded hyperplastic lungs and nitrofen-induced hypoplastic lungs in rats.

Background: Congenital diaphragmatic hernia is accompanied by pulmonary hypoplasia. Fetal lung growth is dependent on the secretion of lung liquid, in which Cl(-) secretion by the pulmonary epithelium plays a crucial role. A decrease of lung liquid production during fetal development renders marked pulmonary hypoplasia, while accelerated fetal lung growth in the form of pulmonary hyperplasia can be achieved by in utero tracheal occlusion (TO).

Erythropoietin modulation of astrocyte water permeability as a component of neuroprotection.

Disturbed brain water homeostasis with swelling of astroglial cells is a common complication in stroke, trauma, and meningitis and is considered to be a major cause of permanent brain damage. Astroglial cells possess the water channel aquaporin 4 (AQP4). Recent studies from our laboratory have shown that glutamate, acting on group I metabotropic glutamate receptors (mGluRs), increases the permeability of astrocyte AQP4, which, in situations of hypoxia-ischemia, will increase astrocyte water uptake.

NKCC-1 and ENaC are down-regulated in nitrofen-induced hypoplastic lungs with congenital diaphragmatic hernia.

Congenital diaphragmatic hernia (CDH) is accompanied by pulmonary hypoplasia and pulmonary hypertension. Fetal lung growth is dependent on the secretion of lung liquid, which normally is absorbed at partus. The ion channel NKCC-1 is involved in this secretory process, but has recently also been reported to be implicated in absorption.

Identification of a molecular target for glutamate regulation of astrocyte water permeability.

Astrocytes play a key role for maintenance of brain water homeostasis, but little is known about mechanisms of short-term regulation of astrocyte water permeability. Here, we report that glutamate increases astrocyte water permeability and that the molecular target for this effect is the aquaporin-4 (AQP4) serine 111 residue, which is in a strategic position for control of the water channel gating. The glutamate effect involves activation of group I metabotropic glutamate receptors (mGluR), intracellular calcium release, and activation of calcium/calmodulin-dependent protein kinase II (CaMKII) and nitric oxide synthase (NOS).

Osmotic water permeability of rat intestinal brush border membrane vesicles: involvement of aquaporin-7 and aquaporin-8 and effect of metal ions.

Water channels AQP7 and AQP8 may be involved in transcellular water movement in the small intestine. We show that both AQP7 and AQP8 mRNA are expressed in rat small intestine. Immunoblot and immunohistochemistry experiments demonstrate that AQP7 and AQP8 proteins are present in the apical brush border membrane of intestinal epithelial cells.

Modified expression of Mts1/S100A4 protein in C6 glioma cells or surrounding astrocytes affects migration of tumor cells in vitro and in vivo.

The calcium-binding Mts1/S100A4 protein plays an important role in motility and metastatic activity of tumor cells. Recently we showed that Mts1/S100A4 is expressed in white matter astrocytes and influences their migration in vitro and in vivo. Here, we have investigated the role of Mts1/S100A4 expression in C6 glioma cells or surrounding astrocytes for migration of C6 cells on astrocytes, using short interference (si) RNA to silence Mts1/S100A4 expression.

Urinary aquaporin-2 excretion during early human development.

This study was undertaken to assess one of the determinants of kidney concentrating capacity, aquaporin-2 (AQP2), in order to understand the physiopathology of water balance in newborn babies. Urinary AQP2 excretion has been shown to be proportional to AQP2 level in the apical plasma membrane of the kidney collecting ducts and has been suggested as a marker of vasopressin (AVP) action. Urinary AQP2 excretion in the early postnatal period and at 3 weeks of age was measured in 123 neonates admitted during a 6-month period to the neonatal intensive care unit of the Children's Hospital of Toulouse, France.

Urinary aquaporin-2 in children with acute pyelonephritis.

Children with acute pyelonephritis develop polyuria and have reduced maximum urinary concentration capacity. We studied whether these abnormalities are associated with altered urinary excretion of the water channel aquaporin-2 (AQP2) in the renal collecting duct. AQP2 is the main target for antidiuretic action of arginine vasopressin (AVP), and the urinary excretion of this protein is believed to be an index of AVP signaling activity in the kidney.

Lead induces increased water permeability in astrocytes expressing aquaporin 4.

The water channel aquaporin 4 (AQP4) is abundantly expressed in astrocytes. There is now compelling evidence that AQP4 may contribute to an unfavorable course in brain edema. Acute lead intoxication is a condition that causes brain damage preceded by brain edema.

Water channels (aquaporins) and their role for postnatal adaptation.

Birth is a transition from an underwater life in the uterus to a terrestrial life in a milieu where supply of water is limited. Rapid adaptation to the new environment is crucial for survival and health of infants. The discovery of a family of molecules-aquaporin (AQP) water channels-that are responsible for regulated water transport across cell membranes has made it possible to identify the molecular mechanisms behind the postnatal homeostatic adaptation and to better understand water imbalance-related disorders in infancy and childhood.

Bidirectional regulation of AQP2 trafficking and recycling: involvement of AQP2-S256 phosphorylation.

The present study examined the role of PKA and serine256 (S256) phosphorylation for AQP2 trafficking and recycling using cells transfected with wild-type AQP2 (AQP2-WT) or mutant AQP2 and high-resolution confocal microscopic techniques. In transiently transfected MDCK-C7 cells, stimulation with forskolin induced translocation of AQP2-WT to the plasma membrane. Treatment of AQP2-WT cells with the PKA inhibitor H-89 following forskolin stimulation resulted in internalization of AQP2-WT.

Regulation of brain aquaporins.

Emerging evidence suggests that brain aquaporins (AQP) play important roles for the dynamic regulation of brain water homeostasis and for the regulation of cerebrospinal fluid production. This review deals with the short- and long-term regulation of AQP4 and AQP9, both expressed in astrocytes, and of AQP1, expressed in the choroid plexus. AQP1 and 4 have in other cell types been shown to be regulated by phosphorylation.

Copper inhibits the water and glycerol permeability of aquaporin-3.

Aquaporin-3 (AQP3) is an aquaglyceroporin expressed in erythrocytes and several other tissues. Erythrocytes are, together with kidney and liver, the main targets for copper toxicity. Here we report that both water and glycerol permeability of human AQP3 is inhibited by copper.

Nickel and extracellular acidification inhibit the water permeability of human aquaporin-3 in lung epithelial cells.

Nickel is a common cause of pneumoconiosis. Here, we show that nickel inactivates aquaporin (AQP)-3, the water channel expressed apically in epithelial cells of human terminal airways. Human AQP3 was transiently transfected into human lung cells, and water permeability was measured in transfected and neighboring untransfected cells.

Water permeability of aquaporin-4 is decreased by protein kinase C and dopamine.

Aquaporin-4 (AQP4) plays an important role in the basolateral movement of water in the collecting duct. Here we show that this water channel can be dynamically regulated. Water permeability (P(f)) was measured in individual LLC-PK1 cells that were transiently transfected with AQP4.