With No Lysine (K) Kinases and Sodium Transporter Function in Solute Exchange with Implications for BP Regulation as Elucidated through Drosophila.

Like other multicellular organisms, the fruit fly Drosophila melanogaster must maintain homeostasis of the internal milieu, including the maintenance of constant ion and water concentrations. In mammals, the with no lysine (K) (WNK)-Ste20-proline/alanine rich kinase/oxidative stress response 1 kinase cascade is an important regulator of epithelial ion transport in the kidney. This pathway regulates SLC12 family cotransporters, including sodium-potassium-2-chloride, sodium chloride, and potassium chloride cotransporters.

Renal L-2-hydroxyglutarate dehydrogenase activity promotes hypoxia tolerance and mitochondrial metabolism in Drosophila melanogaster.

Objectives: The mitochondrial enzyme L-2-hydroxyglutarate dehydrogenase (L2HGDH) regulates the abundance of L-2-hydroxyglutarate (L-2HG), a potent signaling metabolite capable of influencing chromatin architecture, mitochondrial metabolism, and cell fate decisions. Loss of L2hgdh activity in humans induces ectopic L-2HG accumulation, resulting in neurodevelopmental defects, altered immune cell function, and enhanced growth of clear cell renal cell carcinomas. To better understand the molecular mechanisms that underlie these disease pathologies, we used the fruit fly Drosophila melanogaster to investigate the endogenous functions of L2hgdh.

Large analysis of genetic manipulations reveals an inverse correlation between initial alcohol resistance and rapid tolerance phenotypes.

Tolerance occurs when, following an initial experience with a substance, more of the substance is required subsequently to induce identical behavioral effects. Tolerance is not well-understood, and numerous researchers have turned to model organisms, particularly Drosophila melanogaster, to unravel its mechanisms. Flies have high translational relevance for human alcohol responses, and there is substantial overlap in disease-causing genes between flies and humans, including those associated with Alcohol Use Disorder.

Evaluation of renal sodium handling in heart failure with preserved ejection fraction: A pilot study.

The pathophysiology behind sodium retention in heart failure with preserved ejection fraction (HFpEF) remains poorly understood. We hypothesized that patients with HFpEF have impaired natriuresis and diuresis in response to volume expansion and diuretic challenge, which is associated with renal hypo-responsiveness to endogenous natriuretic peptides. Nine HFpEF patients and five controls received saline infusion (0.

Iterative assay for transposase-accessible chromatin by sequencing to isolate functionally relevant neuronal subtypes.

The brain contains tens of thousands of distinct cell types. Thousands of different transgenic lines reproducibly target specific neuron subsets, yet most still express in several cell types. Furthermore, most lines were developed without a priori knowledge of where the transgenes would be expressed.

Large genetic analysis of alcohol resistance and tolerance reveals an inverse correlation and suggests 'true' tolerance mutants.

Tolerance occurs when, following an initial experience with a substance, more of the substance is required subsequently to induce the same behavioral effects. Tolerance is historically not well-understood, and numerous researchers have turned to model organisms, particularly , to unravel its mechanisms. Flies have high translational relevance for human alcohol responses, and there is substantial overlap in disease-causing genes between flies and humans, including those associated with Alcohol Use Disorder.

Unanticipated domain requirements for Drosophila Wnk kinase in vivo.

WNK (With no Lysine [K]) kinases have critical roles in the maintenance of ion homeostasis and the regulation of cell volume. Their overactivation leads to pseudohypoaldosteronism type II (Gordon syndrome) characterized by hyperkalemia and high blood pressure. More recently, WNK family members have been shown to be required for the development of the nervous system in mice, zebrafish, and flies, and the cardiovascular system of mice and fish.

Apolipoprotein L1 Genotypes and the Association of Urinary Potassium Excretion with CKD Progression.

Background And Objectives: Progressive CKD in Black individuals is strongly associated with polymorphisms in the gene, but it is unknown whether dietary risk factors for CKD progression vary in high- versus low-risk genotypes. We investigated if genotypes modify associations of dietary potassium and sodium with CKD progression and death.

Design, Setting, Participants, & Measurements: We analyzed 1399 self-identified Black participants enrolled in the Chronic Renal Insufficiency Cohort from April 2003 to September 2008.

WNK kinases sense molecular crowding and rescue cell volume via phase separation.

When challenged by hypertonicity, dehydrated cells must recover their volume to survive. This process requires the phosphorylation-dependent regulation of SLC12 cation chloride transporters by WNK kinases, but how these kinases are activated by cell shrinkage remains unknown. Within seconds of cell exposure to hypertonicity, WNK1 concentrates into membraneless condensates, initiating a phosphorylation-dependent signal that drives net ion influx via the SLC12 cotransporters to restore cell volume.

Intracellular Ion Control of WNK Signaling.

The with no lysine (K) (WNK) kinases are an evolutionarily ancient group of kinases with atypical placement of the catalytic lysine and diverse physiological roles. Recent studies have shown that WNKs are directly regulated by chloride, potassium, and osmotic pressure. Here, we review the discovery of WNKs as chloride-sensitive kinases and discuss physiological contexts in which chloride regulation of WNKs has been demonstrated.

Regulation of Distal Nephron Transport by Intracellular Chloride and Potassium.

Background: Low potassium increases the phosphorylation and activity of the sodium chloride cotransporter (NCC) in the distal convoluted tubule of the nephron, which contributes to the hypertensive effect of the modern low potassium/high sodium diet. A central mediator of potassium regulation of NCC is the chloride-sensitive With No Lysine [K] (WNK) kinase.

Summary: Chloride directly inhibits WNKs by binding to the active site.

Harnessing changes in open chromatin determined by ATAC-seq to generate insulin-responsive reporter constructs.

Background: Gene regulation is critical for proper cellular function. Next-generation sequencing technology has revealed the presence of regulatory networks that regulate gene expression and essential cellular functions. Studies investigating the epigenome have begun to uncover the complex mechanisms regulating transcription.

Mitochondrial calcium uniporter stabilization preserves energetic homeostasis during Complex I impairment.

Calcium entering mitochondria potently stimulates ATP synthesis. Increases in calcium preserve energy synthesis in cardiomyopathies caused by mitochondrial dysfunction, and occur due to enhanced activity of the mitochondrial calcium uniporter channel. The signaling mechanism that mediates this compensatory increase remains unknown.

Optimized assay for transposase-accessible chromatin by sequencing (ATAC-seq) library preparation from adult Drosophila melanogaster neurons.

Assay for transposase-accessible chromatin by sequencing (ATAC-seq) is rapidly becoming the assay of choice to investigate chromatin-mediated gene regulation, largely because of low input requirements, a fast workflow, and the ability to interrogate the entire genome in an untargeted manner. Many studies using ATAC-seq use mammalian or human-derived tissues, and established protocols work well in these systems. However, ATAC-seq is not yet widely used in Drosophila.

Chloride oscillation in pacemaker neurons regulates circadian rhythms through a chloride-sensing WNK kinase signaling cascade.

Central pacemaker neurons regulate circadian rhythms and undergo diurnal variation in electrical activity in mammals and flies. Circadian variation in the intracellular chloride concentration of mammalian pacemaker neurons has been proposed to influence the response to GABAergic neurotransmission through GABA receptor chloride channels. However, results have been contradictory, and a recent study demonstrated circadian variation in pacemaker neuron chloride without an effect on GABA response.

The fly liquid-food electroshock assay (FLEA) suggests opposite roles for neuropeptide F in avoidance of bitterness and shock.

Background: Proper regulation of feeding is important for an organism's well-being and survival and involves a motivational component directing the search for food. Dissecting the molecular and neural mechanisms of motivated feeding behavior requires assays that allow quantification of both motivation and food intake. Measurements of motivated behavior usually involve assessing physical effort or overcoming an aversive stimulus.