A Novel Antigen Design Strategy to Isolate Single-Domain Antibodies that Target Human Nav1.7 and Reduce Pain in Animal Models.

Genetic studies have identified the voltage-gated sodium channel 1.7 (Na1.7) as pain target.

The elusive Na1.7: From pain to cancer.

Voltage-gated sodium channels (Na) are protein complexes that play fundamental roles in the transmission of signals in the nervous system, at the neuromuscular junction and in the heart. They are mainly present in excitable cells where they are responsible for triggering action potentials. Dysfunctions in Na ion conduction give rise to a wide range of conditions, including neurological disorders, hypertension, arrhythmia, pain and cancer.

Electrophysiological- and Neuropharmacological-Based Benchmarking of Human Induced Pluripotent Stem Cell-Derived and Primary Rodent Neurons.

Human induced pluripotent stem cell (iPSC)-derived neurons are of interest for studying neurological disease mechanisms, developing potential therapies and deepening our understanding of the human nervous system. However, compared to an extensive history of practice with primary rodent neuron cultures, human iPSC-neurons still require more robust characterization of expression of neuronal receptors and ion channels and functional and predictive pharmacological responses. In this study, we differentiated human amniotic fluid-derived iPSCs into a mixed population of neurons (AF-iNs).

The T-type Calcium Channel Cav3.1 in Y79 Retinoblastoma Cells is Regulated by the Epidermal Growth Factor Receptor via the MAPK Signaling Pathway.

Purpose: Retinoblastoma is the most frequent intraocular cancer in children. It is also one of the most common causes for enucleation and carries a significant morbidity rate in affected individuals. Hence, studies on its pathophysiological and growth regulatory mechanisms are urgently needed to identify more effective novel therapeutics.

Potassium and Chloride Ion Channels in Cancer: A Novel Paradigm for Cancer Therapeutics.

Cancer is a collection of diseases caused by specific changes at the genomic level that support cell proliferation indefinitely. Traditionally, ion channels are known to control a variety of cellular processes including electrical signal generation and transmission, secretion, and contraction by controlling ionic gradients. However, recent studies had brought to light important facts on ion channels in cancer biology.

Electrophysiological Alterations of Pyramidal Cells and Interneurons of the CA1 Region of the Hippocampus in a Novel Mouse Model of Dravet Syndrome.

Dravet syndrome is a developmental epileptic encephalopathy caused by pathogenic variation in To characterize the pathogenic substitution (p.H939R) of a local individual with Dravet syndrome, fibroblast cells from the individual were reprogrammed to pluripotent stem cells and differentiated into neurons. Sodium currents of these neurons were compared with healthy control induced neurons.

Ion channel expression and function in normal and osteoarthritic human synovial fluid progenitor cells.

Osteoarthritis (OA) is a chronic disease affecting the cartilage of over 15% of Canadians. Synovial fluid mesenchymal progenitor cells (sfMPCs) are present in joints and are thought to contribute to healing. OA sfMPCs have a greater proliferative ability but decreased chondrogenic potential.

Curcumin blocks Kv11.1 (erg) potassium current and slows proliferation in the infant acute monocytic leukemia cell line THP-1.

Acute Myeloid Leukemia (AML) accounts for approximately one fifth of all childhood leukemia yet is responsible for a significant proportion of morbidity and mortality in this population. For this reason, research to identify novel targets for the development of effective AML therapeutics has intensified in the recent past. The THP-1 cell line, which was originally established from an infant diagnosed with AML, provides an experimental model for functional, pre-clinical therapeutics and target identification studies of AML.

Ion channels in pediatric CNS Atypical Teratoid/Rhabdoid Tumor (AT/RT) cells: potential targets for novel therapeutic agents.

The central nervous system Atypical Teratoid/Rhabdoid Tumor (CNS AT/RT) is a highly malignant neoplasm that commonly affects infants and young children, and has an extremely poor prognosis. Recently, a small subset of ion channels have been found to be over-expressed in a variety of malignant cells, thus emerging as potential therapeutic targets for difficult to treat tumors. We have studied the electrophysiological properties of AT/RT cell lines with particular attention to cell volume sensitive ion channels (VSC).

Measurement of the membrane potential in small cells using patch clamp methods.

The resting membrane potential, E(m), of mammalian cells is a fundamental physiological parameter. Even small changes in E(m) can modulate excitability, contractility and rates of cell migration. At present accurate, reproducible measurements of E(m) and determination of its ionic basis remain significant challenges when patch clamp methods are applied to small cells.

Impaired stretch modulation in potentially lethal cardiac sodium channel mutants.

The presence of two slowly inactivating mutants of the cardiac sodium channel (hNa(V)1.5), R1623Q and R1626P, associate with sporadic Long-QT3 (LQT3) syndrome, and may contribute to ventricular tachyarrhythmias and/or lethal ventricular disturbances. Cardiac mechanoelectric feedback is considered a factor in such sporadic arrhythmias.

Membrane trauma and Na+ leak from Nav1.6 channels.

During brain trauma, white matter experiences shear and stretch forces that, without severing axons, nevertheless trigger their secondary degeneration. In central nervous system (CNS) trauma models, voltage-gated sodium channel (Nav) blockers are neuroprotective. This, plus the rapid tetrodotoxin-sensitive Ca2+ overload of stretch-traumatized axons, points to "leaky" Nav channels as a pivotal early lesion in brain trauma.

Hydrophobic interactions as key determinants to the KCa3.1 channel closed configuration. An analysis of KCa3.1 mutants constitutively active in zero Ca2+.

In this study we present evidence that residue Val282 in the S6 transmembrane segment of the calcium-activated KCa3.1 channel constitutes a key determinant of channel gating. A Gly scan of the S6 transmembrane segment first revealed that the substitutions A279G and V282G cause the channel to become constitutively active in zero Ca2+.

Structural determinants of the closed KCa3.1 channel pore in relation to channel gating: results from a substituted cysteine accessibility analysis.

In this work we address the question of the KCa3.1 channel pore structure in the closed configuration in relation to the contribution of the C-terminal end of the S6 segments to the Ca(2+)-dependent gating process. Our results based on SCAM (substituted cysteine accessibility method) experiments first demonstrate that the S6 transmembrane segment of the open KCa3.

New insights on the voltage dependence of the KCa3.1 channel block by internal TBA.

We present in this work a structural model of the open IKCa (KCa3.1) channel derived by homology modeling from the MthK channel structure, and used this model to compute the transmembrane potential profile along the channel pore. This analysis showed that the selectivity filter and the region extending from the channel inner cavity to the internal medium should respectively account for 81% and 16% of the transmembrane potential difference.

Outer pore topology of the ECaC-TRPV5 channel by cysteine scan mutagenesis.

The substituted cysteine accessibility method (SCAM) was used to map the external vestibule and the pore region of the ECaC-TRPV5 calcium-selective channel. Cysteine residues were introduced at 44 positions from the end of S5 (Glu515) to the beginning of S6 (Ala560). Covalent modification by positively charged MTSET applied from the external medium significantly inhibited whole cell currents at 15/44 positions.

Cysteine mutagenesis and computer modeling of the S6 region of an intermediate conductance IKCa channel.

Cysteine-scanning mutagenesis (SCAM) and computer-based modeling were used to investigate key structural features of the S6 transmembrane segment of the calcium-activated K(+) channel of intermediate conductance IKCa. Our SCAM results show that the interaction of [2-(trimethylammonium)ethyl] methanethiosulfonate bromide (MTSET) with cysteines engineered at positions 275, 278, and 282 leads to current inhibition. This effect was state dependent as MTSET appeared less effective at inhibiting IKCa in the closed (zero Ca(2+) conditions) than open state configuration.