Assessment of the operational characteristics of the National Comprehensive Cancer Network distress management tool, v. 2.2018, in patients seen at the Instituto Nacional de Cancerología, Bogotá.

Introduction: Cancer patients have significant levels of emotional distress. The National Comprehensive Cancer Network (NCCN) developed the distress management tool to quickly assess significant distress in oncological patients who require intervention. For its use in Colombia, we made its cross-cultural adaptation and validation.

MitoBK channel is functionally associated with its regulatory β1 subunit in cardiac mitochondria.

Key Points: Association of plasma membrane BK channels with BK-β subunits shapes their biophysical properties and physiological roles; however, functional modulation of the mitochondrial BK channel (mitoBK ) by BK-β subunits is not established. MitoBK -α and the regulatory BK-β1 subunit associate in mouse cardiac mitochondria. A large fraction of mitoBK display properties similar to that of plasma membrane BK when associated with BK-β1 (left-shifted voltage dependence of activation, V  = -55 mV, 12 µm matrix Ca ).

The mitochondrial BK channel cardiac interactome reveals BK association with the mitochondrial import receptor subunit Tom22, and the adenine nucleotide translocator.

Mitochondrial BK channel, mitoBK, regulates mitochondria function in the heart but information on its protein partnerships in cardiac mitochondria is missing. A directed proteomic approach discovered the novel interaction of BK with Tom22, a component of the mitochondrion outer membrane import system, and the adenine nucleotide translocator (ANT). The expressed protein partners co-immunoprecipitated and co-segregated into mitochondrial fractions in HEK293T cells.

Skeletal muscle action of estrogen receptor α is critical for the maintenance of mitochondrial function and metabolic homeostasis in females.

Impaired estrogen receptor α (ERα) action promotes obesity and metabolic dysfunction in humans and mice; however, the mechanisms underlying these phenotypes remain unknown. Considering that skeletal muscle is a primary tissue responsible for glucose disposal and oxidative metabolism, we established that reduced ERα expression in muscle is associated with glucose intolerance and adiposity in women and female mice. To test this relationship, we generated muscle-specific ERα knockout (MERKO) mice.

Rescue of Pressure Overload-Induced Heart Failure by Estrogen Therapy.

Background: Estrogen pretreatment has been shown to attenuate the development of heart hypertrophy, but it is not known whether estrogen could also rescue heart failure (HF). Furthermore, the heart has all the machinery to locally biosynthesize estrogen via aromatase, but the role of local cardiac estrogen synthesis in HF has not yet been studied. Here we hypothesized that cardiac estrogen is reduced in HF and examined whether exogenous estrogen therapy can rescue HF.

Resonant Scanning with Large Field of View Reduces Photobleaching and Enhances Fluorescence Yield in STED Microscopy.

Photobleaching is a major limitation of superresolution Stimulated Depletion Emission (STED) microscopy. Fast scanning has long been considered an effective means to reduce photobleaching in fluorescence microscopy, but a careful quantitative study of this issue is missing. In this paper, we show that the photobleaching rate in STED microscopy can be slowed down and the fluorescence yield be enhanced by scanning with high speed, enabled by using large field of view in a custom-built resonant-scanning STED microscope.

Resonant-scanning dual-color STED microscopy with ultrafast photon counting: A concise guide.

STED (stimulated emission depletion) is a popular super-resolution fluorescence microscopy technique. In this paper, we present a concise guide to building a resonant-scanning STED microscope with ultrafast photon-counting acquisition. The STED microscope has two channels, using a pulsed laser and a continuous-wave (CW) laser as the depletion laser source, respectively.

BK Channels Alleviate Lysosomal Storage Diseases by Providing Positive Feedback Regulation of Lysosomal Ca2+ Release.

Promoting lysosomal trafficking represents a promising therapeutic approach for lysosome storage diseases. Efficient Ca(2+) mobilization from lysosomes is important for lysosomal trafficking. Ca(2+) release from lysosomes could generate a negative potential in the lumen to disturb subsequent Ca(2+) release in the absence of counter ion flux.

Mitochondrial BKCa channel.

Since its discovery in a glioma cell line 15 years ago, mitochondrial BKCa channel (mitoBKCa) has been studied in brain cells and cardiomyocytes sharing general biophysical properties such as high K(+) conductance (~300 pS), voltage-dependency and Ca(2+)-sensitivity. Main advances in deciphering the molecular composition of mitoBKCa have included establishing that it is encoded by the Kcnma1 gene, that a C-terminal splice insert confers mitoBKCa ability to be targeted to cardiac mitochondria, and evidence for its potential coassembly with β subunits. Notoriously, β1 subunit directly interacts with cytochrome c oxidase and mitoBKCa can be modulated by substrates of the respiratory chain.

A strategy to improve treatment-related mortality and abandonment of therapy for childhood ALL in a developing country reveals the impact of treatment delays.

Background: Treatment-related mortality and abandonment of therapy are major barriers to successful treatment of childhood acute lymphoblastic leukemia (ALL) in the developing world.

Procedure: A collaboration was undertaken between Instituto Nacional de Cancerologia (Bogota, Colombia), which serves a poor patient population in an upper-middle income country, and Dana-Farber/Boston Children's Cancer and Blood Disorders Center (Boston, USA). Several interventions aimed at reducing toxic deaths and abandonment were implemented, including a reduced-intensity treatment regimen and a psychosocial effort targeting abandonment.

Regulation of transcriptional activation function of rat estrogen receptor α (ERα) by novel C-terminal splice inserts.

Estrogen receptor α (ERα) mediates estrogen diverse actions on tissues. ERα gene has eight constitutively expressing exons and is known to have multiple isoforms generated by alternative initiation of transcription and splicing events including exon skipping. We have discovered two novel exons inserted between exon 5 and 6 of rat ERα that can add independently or in tandem 18 and 14 amino acids to the estrogen binding/activator function 2 domain of the receptor.

Both transmembrane domains of BK β1 subunits are essential to confer the normal phenotype of β1-containing BK channels.

Voltage/Ca²⁺(i)-gated, large conductance K+ (BK) channels result from tetrameric association of α (slo1) subunits. In most tissues, BK protein complexes include regulatory β subunits that contain two transmembrane domains (TM1, TM2), an extracellular loop, and two short intracellular termini. Four BK β types have been identified, each presenting a rather selective tissue-specific expression profile.

Ultrafast photon counting applied to resonant scanning STED microscopy.

To take full advantage of fast resonant scanning in super-resolution stimulated emission depletion (STED) microscopy, we have developed an ultrafast photon counting system based on a multigiga sample per second analogue-to-digital conversion chip that delivers an unprecedented 450 MHz pixel clock (2.2 ns pixel dwell time in each scan). The system achieves a large field of view (∼50 × 50 μm) with fast scanning that reduces photobleaching, and advances the time-gated continuous wave STED technology to the usage of resonant scanning with hardware-based time-gating.

The angiotensin II type 1 receptor (AT1R) closely interacts with large conductance voltage- and Ca2+-activated K+ (BK) channels and inhibits their activity independent of G-protein activation.

Angiotensin II (ANG-II) and BK channels play important roles in the regulation of blood pressure. In arterial smooth muscle, ANG-II inhibits BK channels, but the underlying molecular mechanisms are unknown. Here, we first investigated whether ANG-II utilizes its type 1 receptor (AT1R) to modulate BK activity.

MaxiK channel and cell signalling.

The large-conductance Ca2+- and voltage-activated K+ (MaxiK, BK, BKCa, Slo1, KCa1.1) channel role in cell signalling is becoming apparent as we learn how the channel interacts with a multiplicity of proteins not only at the plasma membrane but also in intracellular organelles including the endoplasmic reticulum, nucleus, and mitochondria. In this review, we focus on the interactions of MaxiK channels with seven-transmembrane G protein-coupled receptors and discuss information suggesting that, the channel big C-terminus may act as the nucleus of signalling molecules including kinases relevant for cell death and survival.

MitoBK(Ca) is encoded by the Kcnma1 gene, and a splicing sequence defines its mitochondrial location.

The large-conductance Ca(2+)- and voltage-activated K(+) channel (BK(Ca), MaxiK), which is encoded by the Kcnma1 gene, is generally expressed at the plasma membrane of excitable and nonexcitable cells. However, in adult cardiomyocytes, a BK(Ca)-like channel activity has been reported in the mitochondria but not at the plasma membrane. The putative opening of this channel with the BK(Ca) agonist, NS1619, protects the heart from ischemic insult.

The β1-subunit of the MaxiK channel associates with the thromboxane A2 receptor and reduces thromboxane A2 functional effects.

The large conductance voltage- and Ca(2+)-activated K(+) channel (MaxiK, BK(Ca), BK) is composed of four pore-forming α-subunits and can be associated with regulatory β-subunits. One of the functional roles of MaxiK is to regulate vascular tone. We recently found that the MaxiK channel from coronary smooth muscle is trans-inhibited by activation of the vasoconstricting thromboxane A(2) prostanoid receptor (TP), a mechanism supported by MaxiK α-subunit (MaxiKα)-TP physical interaction.

Intracellular BK(Ca) (iBK(Ca)) channels.

The large conductance calcium- and voltage-activated potassium channel (BK(Ca)) is widely expressed at the plasma membrane. This channel is involved in a variety of fundamental cellular functions including excitability, smooth muscle contractility, and Ca(2+) homeostasis, as well as in pathological situations like proinflammatory responses in rheumatoid arthritis, and cancer cell proliferation. Immunochemical, biochemical and pharmacological studies from over a decade have intermittently shown the presence of BK(Ca) in intracellular organelles.

The first transmembrane domain (TM1) of β2-subunit binds to the transmembrane domain S1 of α-subunit in BK potassium channels.

The BK channel is one of the most broadly expressed ion channels in mammals. In many tissues, the BK channel pore-forming α-subunit is associated to an auxiliary β-subunit that modulates the voltage- and Ca(2+)-dependent activation of the channel. Structural components present in β-subunits that are important for the physical association with the α-subunit are yet unknown.

Visualization and quantification of cardiac mitochondrial protein clusters with STED microscopy.

The visualization and quantification of mitochondria-associated proteins with high power microscopy methods is of particular interest to investigate protein architecture in this organelle. We report the usage of a custom-made STimulated Emission Depletion (STED) fluorescence nanoscope with ~30nm lateral resolution for protein mapping of Percoll-purified viable mitochondria from murine heart. Using this approach, we were able to quantify and resolve distinct protein clusters within mitochondria; specifically, cytochrome c oxidase subunit 2 is distributed in clusters of ~28nm; whereas the voltage dependent anion channel 1 displays three size distributions of ~33, ~55 and ~83nm.

Distinct transcriptional regulation of human large conductance voltage- and calcium-activated K+ channel gene (hSlo1) by activated estrogen receptor alpha and c-Src tyrosine kinase.

Estrogen receptor α (ERα) regulates gene transcription via "genomic" (binding directly or indirectly, typically via Sp1 or AP-1 sites, to target genes) and/or "nongenomic" (signaling) mechanisms. ERα activation by estrogen up-regulates the murine Ca(2+)-activated K(+) channel α subunit gene (mSlo1) via genomic mechanisms. Here, we investigated whether ERα also drives transcription of the human (hSlo1) gene.

Unconventional myristoylation of large-conductance Ca²⁺-activated K⁺ channel (Slo1) via serine/threonine residues regulates channel surface expression.

Protein myristoylation is a means by which cells anchor proteins into membranes. The most common type of myristoylation occurs at an N-terminal glycine. However, myristoylation rarely occurs at an internal amino acid residue.

Thromboxane A2 receptor and MaxiK-channel intimate interaction supports channel trans-inhibition independent of G-protein activation.

Large conductance voltage- and calcium-activated potassium channels (MaxiK, BK(Ca)) are well known for sustaining cerebral and coronary arterial tone and for their linkage to vasodilator β-adrenergic receptors. However, how MaxiK channels are linked to counterbalancing vasoconstrictor receptors is unknown. Here, we show that vasopressive thromboxane A2 receptors (TP) can intimately couple with and inhibit MaxiK channels.

Quantitative determination of spatial protein-protein correlations in fluorescence confocal microscopy.

To quantify spatial protein-protein proximity (colocalization) in paired microscopic images of two sets of proteins labeled by distinct fluorophores, we showed that the cross-correlation and the autocorrelation functions of image intensity consisted of fast and slowly decaying components. The fast component resulted from clusters of proteins specifically labeled, and the slow component resulted from image heterogeneity and a broadly-distributed background. To better evaluate spatial proximity between the two specifically labeled proteins, we extracted the fast-decaying component by fitting the sharp peak in correlation functions to a Gaussian function, which was then used to obtain protein-protein proximity index and the Pearson's correlation coefficient.

A novel estrogen receptor GPER inhibits mitochondria permeability transition pore opening and protects the heart against ischemia-reperfusion injury.

Several studies have recently demonstrated that G protein-coupled receptor 30 (GPER) can directly bind to estrogen and mediate its action. We investigated the role and the mechanism of estrogen-induced cardioprotection after ischemia-reperfusion using a specific GPER agonist G1. Isolated hearts from male mice were perfused using Langendorff technique with oxygenated (95% O(2) and 5% CO(2)) Krebs Henseleit buffer (control), with G1 (1 microM), and G1 (1 microM) together with extracellular signal-regulated kinase (Erk) inhibitor PD-98059 (5 microM).