nkcc1

In this study we have used an antibody that specifically detects the phosphorylation status of the Sodium/Potassium/2 Chloride Cotransporter (NKCC1) to study whether the activity of NKCC1 can be regulated in organ cultured bovine lenses. Western blotting was first used to confirm the expression of NKCC1, phosphorylated NKCC1 (NKCC1-P) and the regulatory kinases WNK/SPAK and phosphatases PP1/PP2A in bovine lenses at the protein level. Changes to NKCC1-P status were then assessed by organ culturing bovine lenses in either isotonic, hypertonic or hypotonic solutions in the presence or absence of the NKCC inhibitor, bumetanide, or phosphatase inhibitors okadaic acid and calyculin A...

In physiological conditions, adult neurons have low intracellular Cl(-) [(Cl(-))I] levels underlying the γ-aminobutyric acid (GABA)ergic inhibitory drive. In contrast, neurons have high (Cl(-))I levels and excitatory GABA actions in a wide range of pathological conditions including spinal cord lesions, chronic pain, brain trauma, cerebrovascular infarcts, autism, Rett and Down syndrome, various types of epilepsies, and other genetic or environmental insults. The diuretic highly specific NKCC1 chloride importer antagonist bumetanide (PubChem CID: 2461) efficiently restores low (Cl(-))I levels and attenuates many disorders in experimental conditions and in some clinical trials...

The devastating consequences of hepatic failure include hepatic encephalopathy, a severe, life threatening impairment of neuronal function. Hepatic encephalopathy is caused by impaired hepatic clearance of NH4(+). Cellular NH4(+) uptake is accomplished mainly by the Na(+),K(+),2Cl(-) cotransporter. Here we show that hepatic clearance of NH4(+) is impaired in TNFα deficient as well as TNFR1&TNFR2 double knockout mice, which both develop hyperammonemia. Despite impaired hepatic clearance of NH4(+), TNFα deficient mice and TNFR1 deficient mice were protected against acute ammonia intoxication...

Dysregulated human eccrine sweat glands can negatively impact the quality-of-life of people suffering from disorders like hyperhidrosis. Inability of sweating can even result in serious health effects in humans affected by anhidrosis. The underlying mechanisms must be elucidated and a reliable in vitro test system for drug screening must be developed. Here we describe a novel organotypic three-dimensional (3D) sweat gland model made of primary human eccrine sweat gland cells. Initial experiments revealed that eccrine sweat gland cells in a two-dimensional (2D) culture lose typical physiological markers...

The choroid plexus epithelium (CPE) secretes higher volumes of fluid (cerebrospinal fluid, CSF) than any other epithelium and simultaneously functions as the blood-CSF barrier to gate immune cell entry into the central nervous system. Posthemorrhagic hydrocephalus (PHH), an expansion of the cerebral ventricles due to CSF accumulation following intraventricular hemorrhage (IVH), is a common disease usually treated by suboptimal CSF shunting techniques. PHH is classically attributed to primary impairments in CSF reabsorption, but little experimental evidence supports this concept...

We previously showed that angiotensin II (Ang II) increases T cell production of IL-17A, and that mice deficient in IL-17A have blunted hypertension and attenuated renal and vascular dysfunction. It was recently shown that salt enhances IL-17A production from CD4+ T cells via a serum- and glucocorticoid-regulated kinase 1-dependent (SGK1-dependent) pathway. Thus, we tested the hypothesis that SGK1 signaling in T cells promotes hypertension and contributes to end-organ damage. We show that loss of T cell SGK1 results in a blunted hypertensive response to Ang II infusion by 25 mmHg...

Glioblastoma (GBM) is the most aggressive primary brain tumor in adults. The mechanisms that confer GBM cells their invasive behavior are poorly understood. The electroneutral Na(+)-K(+)-2Cl(-) co-transporter 1 (NKCC1) is an important cell volume regulator that participates in cell migration. We have shown that inhibition of NKCC1 in GBM cells leads to decreased cell migration, in vitro and in vivo. We now report on the role of NKCC1 on cytoskeletal dynamics. We show that GBM cells display a significant decrease in F-actin content upon NKCC1 knockdown (NKCC1-KD)...

Decreased inhibition plays an extremely important role in pathogenesis of autism spectrum disorder (ASD). Therefore, we aimed to determine whether expression levels of the γ-aminobutyric acid type A receptor β3 subunit (GABAARβ3), K(+)-Cl(-) cotransporter 2 (KCC2), and Na(+)-K(+)-Cl(-) cotransporter 1 (NKCC1) related to inhibition transmission are changed in a sodium valproate-induced rat model of ASD. Decreased expression levels of membrane GABAARβ3 (m-GABAARβ3) and KCC2 as well as increased endocytosis of GABAARs were found in the model group...

A high-throughput screening (HTS) assay was developed for cotransporter, NKCC1, which is a potential target for the treatment of diverse disorders. This nonradioactive rubidium flux assay coupled with ion channel reader series provides a working screen for this target expressed in human embryonic kidney (HEK) cell line. An eightfold window of detection was achieved with the optimized assay. This new functional assay offered a robust working model for NKCC1 in determining reliable and concordant rank orders of the test compounds supporting its sensitivity and specificity...

Traumatic brain injury (TBI) can lead to long-term motor and cognitive dysfunction, which can be at least partly attributed to blood-brain barrier (BBB) disruption. The mechanisms underlying post-TBI BBB disruption, however, are poorly understood thus far. Na(+)-K(+)-2Cl(-) cotransporter isoform 1 (NKCC1) is a universally expressed ion transporter that maintains intracellular ion homeostasis by increasing intracellular K(+) and Cl(-). Having been characterized in stroke models, NKCC1 is activated in various cell types in the ischemic brain, and is thought to mediate BBB disruption, brain edema, and neuronal cell death...

Flavonoids keep us healthy by controlling various body and cellular functions. It is well known that cations, such as Na(+) , K(+) , and Ca(2+) , play important roles in the regulation of body and cellular functions, including generation of action potentials and the resting membrane potential of neural and muscle cells and signal transduction as intracellular second messengers. However, we have little information on the physiological roles of anions, particularly Cl(-) , in body and cellular functions. Quercetin, a flavonoid, stimulates Na(+) -K(+) -2Cl(-) cotransporter 1 (NKCC1), which is one of the most important ion transporters regulating the cytosolic Cl(-) concentration ([Cl(-) ]c )...

In the mammalian ear, transduction of sound stimuli is initiated by K(+) entry through mechano-sensitive channels into inner hair cells. K(+) entry is driven by a positive endocochlear potential that is maintained by the marginal cell layer of the stria vascularis. This process requires basolateral K(+) import by NKCC1 Na(+)-2Cl(-)-K(+) co-transporters as well as Cl(-) efflux through ClC-Ka/barttin or ClC-Kb/barttin channels. Multiple mutations in the gene encoding the obligatory CLC-K subunit barttin, BSND, have been identified in patients with Bartter syndrome type IV...

Mechanoelectrical transduction in the vertebrate inner ear is a highly conserved mechanism depending on K(+) influx into hair cells. Here, we investigated the molecular underpinnings of subsequent K(+) recycling in the chicken basilar papilla and compared it with those in the mammalian auditory sensory epithelium. Like mammals, the avian auditory hair cell uses KCNQ4, KCNMA1, and KCNMB1 as K(+) efflux systems. Expression of KCNQ1 and KCNE1 suggests an additional efflux apparatus in avian hair cells. Marked differences were observed for K(+) clearance...

BACKGROUND: Astaxanthin (ATX) is a carotenoid pigment with pleiotropic pharmacological properties that is seen as a possible drug for treating cerebral ischemic injury and subarachnoid hemorrhage. Na(+)-K(+)-2Cl(-) co-transporter-1 (NKCC1), an intrinsic membrane protein expressed by many cell types, is activated by various insults, leading to the formation of cell swelling and brain edema. We previously established that ATX attenuated brain edema and improved neurological outcomes by modulating NKCC1 expression after traumatic brain injury in mice...

Uropathogenic Escherichia coli often produce the virulence factor α-hemolysin (HlyA), and the more severe the infection, the likelier it is to isolate HlyA-producing E. coli from patients. HlyA forms pores upon receptor-independent insertion of the toxin into biological membranes and it has been substantiated that HlyA-induced hemolysis is amplified by toxin-induced ATP release and activation of P2X receptors. Thus, hemolysis inflicted by HlyA is a protracted process involving signal transduction. It consists of early, marked cell shrinkage followed by swelling and eventually lysis...

Studies have reported that the subiculum is one origin of interictal-like discharges in adult patients with temporal lobe epilepsy; however, whether the subiculum represents a site of ictogenesis for neonatal seizures remains unclear. In this study, multi-electrode recording techniques were used to record epileptiform discharges induced by low-Mg(2+) or high-K(+) artificial cerebrospinal fluid in neonatal mouse hippocampal slices, and the spatiotemporal dynamics of the epileptiform discharges were analyzed...

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Pulmonary edema, a major complication of lung injury and inflammation, is defined as accumulation of extravascular fluid in the lungs leading to impaired diffusion of respiratory gases. Lung fluid balance across the alveolar epithelial barrier protects the distal airspace from excess fluid accumulation and is mainly regulated by active sodium transport and Cl(-) absorption. Increased hydrostatic pressure as seen in cardiogenic edema or increased vascular permeability as present in inflammatory lung diseases such as the acute respiratory distress syndrome (ARDS) causes a reversal of transepithelial fluid transport resulting in the formation of pulmonary edema...

Gamma-aminobutyric acid (GABA) depolarizes dorsal root ganglia (DRG) primary afferent neurons through activation of Cl(-) permeable GABAA receptors but the physiologic role of GABAA receptors in the peripheral terminals of DRG neurons remains unclear. In this study, we investigated the role of peripheral GABAA receptors in nociception using a mouse model of acute inflammation. In vivo, peripheral administration of the selective GABAA receptor agonist muscimol evoked spontaneous licking behavior, as well as spinal wide dynamic range (WDR) neuron firing, after pre-conditioning with formalin but had no effect in saline-treated mice...

BACKGROUND: The majority of studies evaluating neurocognition in humans who had procedures under anesthesia early in life found long-term deficits even though the typical anesthesia duration normalized to the human life span is much shorter than that shown to induce developmental abnormalities in rodents. Therefore, we studied whether subsequent environmental stressors contribute to deficiencies programmed by a brief neonatal etomidate exposure. METHODS: Postnatal days (P) 4, 5, or 6, Sprague-Dawley rats, pretreated with vehicle or the Na(+)-K(+)-2Cl(-) (NKCC1) inhibitor, bumetanide, received two injections of etomidate resulting in anesthesia for 2h...