scholarly journals Small Molecule Channels Harness Membrane Potential to Concentrate Potassium in trk1Δtrk2Δ Yeast

2020 ◽  
Author(s):  
Jennifer Hou ◽  
Page N. Daniels ◽  
Martin D. Burke
Keyword(s):  
Membrane Potential ◽  
Ion Channels ◽  
Small Molecule ◽  
Bartter Syndrome ◽  
Potassium Ions ◽  
Chemical Gradient ◽  
Potassium Transporters ◽  
Proximal Renal Tubular Acidosis ◽  
Renal Tubular

ABSTRACTMany protein ion channels harness membrane potential to move ions in opposition to their chemical gradient. Deficiencies of such proteins cause several human diseases, including cystic fibrosis, Bartter Syndrome Type II, and proximal renal tubular acidosis. Using yeast as a readily manipulated eukaryotic model system, we asked whether, in the context of a deficiency of such protein ion channel function in vivo, small molecule channels could similarly harness membrane potential to concentrate ions. In yeast, Trk potassium transporters use membrane potential to move potassium ions from a compartment of relatively low concentration outside cells (∼15mM) to one of >10 times higher concentration inside (150-500mM). trk1Δtrk2Δ yeast are missing these potassium transporters and thus cannot concentrate potassium or grow in standard media. Here we show that potassium permeable, but not potassium selective, small molecule ion channels formed by the natural product amphotericin B can harness membrane potential to concentrate potassium in trk1Δtrk2Δ cells and thereby restore growth. This finding expands the list of potential human channelopathies that might be addressed by a molecular prosthetics approach.

scholarly journals HGG-02. NEUROPHYSIOLOGICAL SMALL MOLECULE SCREEN TO TARGET NEURON-GLIOMA INTERACTIONS IN PEDIATRIC HIGH-GRADE GLIOMAS

2021 ◽  
Vol 23 (Supplement_1) ◽  
pp. i17-i17
Author(s):  
David Rogawski ◽  
Sara Mulinyawe ◽  
Craig Thomas ◽  
Michelle Monje
Keyword(s):  
Ion Channels ◽  
Small Molecule ◽  
Glioma Cells ◽  
High Grade Glioma ◽  
High Grade ◽  
In Vivo Experiments ◽  
Target Neuron ◽  
Glioma Cell Proliferation ◽  
Glioma Growth

Abstract Neurons stimulate glioma growth via synaptic and paracrine signaling mechanisms. We recently demonstrated that neurons form AMPA receptor-dependent synapses with glioma cells, and that neuronal activity also induces potassium-evoked currents that are amplified by gap junctions coupling glioma cells. However, our understanding of the neurotransmitters, receptors, and ion channels participating in neuron-glioma signaling remains incomplete. We have recently developed a high-throughput neuron-glioma co-culture strategy to screen small molecules for agents that may disrupt neuron-glioma signaling. Glioma cell proliferation is increased tenfold when cultured together with neurons; this robust biological effect can be probed in a targeted screen of compounds influencing neurotransmitter receptors and ion channels. The neurophysiological small molecule library used was curated to include approved anti-epileptics, neuroleptics, and antidepressants, as well as a variety of other compounds acting on different neurotransmitter types and ion channels. Hits from the primary screen were run through a counter-screen using glioma cells grown alone without neurons, to identify compounds that specifically affect neuron-glioma interactions. Correlation of the screening results with drug mechanisms of action will allow us to map out the key neurotransmitter pathways regulating glioma growth, which can be further validated using genetic and in vivo experiments. Drugs identified in this glioma neuroscience screen may be readily translated into much-needed therapeutics for children with high-grade glioma.

120-LB: Small Molecule Activator of Pyruvate Kinase Regulates In Vivo Glucose Homeostasis

Diabetes ◽  
2020 ◽  
Vol 69 (Supplement 1) ◽  
pp. 120-LB
Author(s):  
ABUDUKADIER ABULIZI ◽  
REBECCA L. CARDONE ◽  
STEPHAN SIEBEL ◽  
CHARLES KUNG ◽  
RICHARD KIBBEY
Keyword(s):  
Pyruvate Kinase ◽  
Small Molecule ◽  
Glucose Homeostasis

Quantitative Ranking of Ligand Binding Kinetics with a Multiscale Milestoning Simulation Approach

2018 ◽  
Author(s):  
Benjamin R. Jagger ◽  
Christoper T. Lee ◽  
Rommie Amaro
Keyword(s):  
Molecular Dynamics ◽  
Drug Discovery ◽  
Small Molecule ◽  
Brownian Dynamics ◽  
Model Simulation ◽  
Computational Cost ◽  
Lead Selection ◽  
Delta G ◽  
Dynamics Simulations

<p>The ranking of small molecule binders by their kinetic (kon and koff) and thermodynamic (delta G) properties can be a valuable metric for lead selection and optimization in a drug discovery campaign, as these quantities are often indicators of in vivo efficacy. Efficient and accurate predictions of these quantities can aid the in drug discovery effort, acting as a screening step. We have previously described a hybrid molecular dynamics, Brownian dynamics, and milestoning model, Simulation Enabled Estimation of Kinetic Rates (SEEKR), that can predict kon’s, koff’s, and G’s. Here we demonstrate the effectiveness of this approach for ranking a series of seven small molecule compounds for the model system, -cyclodextrin, based on predicted kon’s and koff’s. We compare our results using SEEKR to experimentally determined rates as well as rates calculated using long-timescale molecular dynamics simulations and show that SEEKR can effectively rank the compounds by koff and G with reduced computational cost. We also provide a discussion of convergence properties and sensitivities of calculations with SEEKR to establish “best practices” for its future use.</p>

A Small Molecule – Protein Hybrid for Voltage Imaging via Quenching of Bioluminescence

2020 ◽  
Author(s):  
Brittany Benlian ◽  
Pavel Klier ◽  
Kayli Martinez ◽  
Marie Schwinn ◽  
Thomas Kirkland ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Membrane Potential ◽  
Small Molecule ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Live Cells ◽  
Potential Oscillations ◽  
Excitation Light ◽  
Voltage Imaging ◽  
Induced Pluripotent

<p>We report a small molecule enzyme pair for optical voltage sensing via quenching of bioluminescence. This <u>Q</u>uenching <u>B</u>ioluminescent V<u>olt</u>age Indicator, or Q-BOLT, pairs the dark absorbing, voltage-sensitive dipicrylamine with membrane-localized bioluminescence from the luciferase NanoLuc (NLuc). As a result, bioluminescence is quenched through resonance energy transfer (QRET) as a function of membrane potential. Fusion of HaloTag to NLuc creates a two-acceptor bioluminescence resonance energy transfer (BRET) system when a tetramethylrhodamine (TMR) HaloTag ligand is ligated to HaloTag. In this mode, Q-BOLT is capable of providing direct visualization of changes in membrane potential in live cells via three distinct readouts: change in QRET, BRET, and the ratio between bioluminescence emission and BRET. Q-BOLT can provide up to a 29% change in bioluminescence (ΔBL/BL) and >100% ΔBRET/BRET per 100 mV change in HEK 293T cells, without the need for excitation light. In cardiac monolayers derived from human induced pluripotent stem cells (hiPSC), Q-BOLT readily reports on membrane potential oscillations. Q-BOLT is the first example of a hybrid small molecule – protein voltage indicator that does not require excitation light and may be useful in contexts where excitation light is limiting.</p> <p> </p>

A Small Molecule – Protein Hybrid for Voltage Imaging via Quenching of Bioluminescence

2020 ◽  
Author(s):  
Brittany Benlian ◽  
Pavel Klier ◽  
Kayli Martinez ◽  
Marie Schwinn ◽  
Thomas Kirkland ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Membrane Potential ◽  
Small Molecule ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Live Cells ◽  
Potential Oscillations ◽  
Excitation Light ◽  
Voltage Imaging ◽  
Induced Pluripotent

<p>We report a small molecule enzyme pair for optical voltage sensing via quenching of bioluminescence. This <u>Q</u>uenching <u>B</u>ioluminescent V<u>olt</u>age Indicator, or Q-BOLT, pairs the dark absorbing, voltage-sensitive dipicrylamine with membrane-localized bioluminescence from the luciferase NanoLuc (NLuc). As a result, bioluminescence is quenched through resonance energy transfer (QRET) as a function of membrane potential. Fusion of HaloTag to NLuc creates a two-acceptor bioluminescence resonance energy transfer (BRET) system when a tetramethylrhodamine (TMR) HaloTag ligand is ligated to HaloTag. In this mode, Q-BOLT is capable of providing direct visualization of changes in membrane potential in live cells via three distinct readouts: change in QRET, BRET, and the ratio between bioluminescence emission and BRET. Q-BOLT can provide up to a 29% change in bioluminescence (ΔBL/BL) and >100% ΔBRET/BRET per 100 mV change in HEK 293T cells, without the need for excitation light. In cardiac monolayers derived from human induced pluripotent stem cells (hiPSC), Q-BOLT readily reports on membrane potential oscillations. Q-BOLT is the first example of a hybrid small molecule – protein voltage indicator that does not require excitation light and may be useful in contexts where excitation light is limiting.</p> <p> </p>

Metabolism and Distribution of Novel Tumor Targeting Drugs In Vivo

2020 ◽  
Vol 21 (13) ◽  
pp. 996-1008
Author(s):  
Mengli Wang ◽  
Qiuzheng Du ◽  
Lihua Zuo ◽  
Peng Xue ◽  
Chao Lan ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Small Molecule ◽  
High Efficiency ◽  
Tumor Therapy ◽  
Research Progress ◽  
Future Research ◽  
Pharmacokinetic Parameters ◽  
Molecular Characteristics ◽  
Targeted Drugs

Background: As a new tumor therapy, targeted therapy is becoming a hot topic due to its high efficiency and low toxicity. Drug effects of targeted tumor drugs are closely related to pharmacokinetics, so it is important to understand their distribution and metabolism in vivo. Methods: A systematic review of the literature on the metabolism and distribution of targeted drugs over the past 20 years was conducted, and the pharmacokinetic parameters of approved targeted drugs were summarized in combination with the FDA's drug instructions. Targeting drugs are divided into two categories: small molecule inhibitors and monoclonal antibodies. Novel targeting drugs and their mechanisms of action, which have been developed in recent years, are summarized. The distribution and metabolic processes of each drug in the human body are reviewed. Results: In this review, we found that the distribution and metabolism of small molecule kinase inhibitors (TKI) and monoclonal antibodies (mAb) showed different characteristics based on the differences of action mechanism and molecular characteristics. TKI absorbed rapidly (Tmax ≈ 1-4 h) and distributed in large amounts (Vd > 100 L). It was mainly oxidized and reduced by cytochrome P450 CYP3A4. However, due to the large molecular diameter, mAb was distributed to tissues slowly, and the volume of distribution was usually very low (Vd < 10 L). It was mainly hydrolyzed and metabolized into peptides and amino acids by protease hydrolysis. In addition, some of the latest drugs are still in clinical trials, and the in vivo process still needs further study. Conclusion: According to the summary of the research progress of the existing targeting drugs, it is found that they have high specificity, but there are still deficiencies in drug resistance and safety. Therefore, the development of safer and more effective targeted drugs is the future research direction. Meanwhile, this study also provides a theoretical basis for clinical accurate drug delivery.

scholarly journals Emerging Roles for Ion Channels in Ovarian Cancer: Pathomechanisms and Pharmacological Treatment

Cancers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 668
Author(s):  
Concetta Altamura ◽  
Maria Raffaella Greco ◽  
Maria Rosaria Carratù ◽  
Rosa Angela Cardone ◽  
Jean-François Desaphy
Keyword(s):  
Ovarian Cancer ◽  
Ion Channels ◽  
Transient Receptor Potential ◽  
Critical Role ◽  
Gynecologic Cancer ◽  
Receptor Potential ◽  
Transient Receptor Potential Channels ◽  
Platinum Resistance

Ovarian cancer (OC) is the deadliest gynecologic cancer, due to late diagnosis, development of platinum resistance, and inadequate alternative therapy. It has been demonstrated that membrane ion channels play important roles in cancer processes, including cell proliferation, apoptosis, motility, and invasion. Here, we review the contribution of ion channels in the development and progression of OC, evaluating their potential in clinical management. Increased expression of voltage-gated and epithelial sodium channels has been detected in OC cells and tissues and shown to be involved in cancer proliferation and invasion. Potassium and calcium channels have been found to play a critical role in the control of cell cycle and in the resistance to apoptosis, promoting tumor growth and recurrence. Overexpression of chloride and transient receptor potential channels was found both in vitro and in vivo, supporting their contribution to OC. Furthermore, ion channels have been shown to influence the sensitivity of OC cells to neoplastic drugs, suggesting a critical role in chemotherapy resistance. The study of ion channels expression and function in OC can improve our understanding of pathophysiology and pave the way for identifying ion channels as potential targets for tumor diagnosis and treatment.

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