scholarly journals Structure-guided design of a cell penetrating peptide preventing cAMP modulation of HCN channels

2018 ◽  
Author(s):  
Andrea Saponaro ◽  
Francesca Cantini ◽  
Alessandro Porro ◽  
Annalisa Bucchi ◽  
Dario Di Francesco ◽  
...  
Keyword(s):  
Hcn Channels ◽  
Nucleotide Binding Domain ◽  
Adrenergic Stimulation ◽  
Action Potential Firing ◽  
Auxiliary Subunit ◽  
Cell Penetrating ◽  
Direct Competition ◽  
Potential Firing ◽  
A Cell ◽  
Camp Stimulation

AbstractThe auxiliary subunit TRIP8b prevents cAMP activation of HCN channels by antagonizing its binding to their cyclic-nucleotide binding domain (CNBD). By determining an NMR-derived structure of the complex formed by the HCN2 channel CNBD and a minimal TRIP8b fragment, TRIPnano, we show here a bipartite interaction between the peptide and CNBD which prevents cAMP binding in two ways: through direct competition for binding at the distal C-helix of the CNBD; and through an allosteric reduction in cAMP affinity induced by TRIP8b binding to the CNBD N-bundle loop. TRIPnano abolishes cAMP binding in all three isoforms, HCN1, HCN2 and HCN4 and can be used to prevent cAMP stimulation in native f-channels. Application of TRIP8bnano, or its delivery via a cell-penetrating sequence, in sinoatrial node myocytes, selectively inhibits beta-adrenergic stimulation of the native If current and mimics the physiological concentrations of acetylcholine leading to a 30% reduction in the spontaneus rate of action potential firing.

scholarly journals A synthetic peptide that prevents cAMP regulation in mammalian hyperpolarization-activated cyclic nucleotide-gated (HCN) channels

eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Andrea Saponaro ◽  
Francesca Cantini ◽  
Alessandro Porro ◽  
Annalisa Bucchi ◽  
Dario DiFrancesco ◽  
...  
Keyword(s):  
Cyclic Nucleotide ◽  
Rational Design ◽  
Structural Model ◽  
Hcn Channels ◽  
Nucleotide Binding Domain ◽  
Novel Approach ◽  
A Cell ◽  
The Central Nervous System ◽  
The Brain ◽  
Adrenergic Activation

Binding of TRIP8b to the cyclic nucleotide binding domain (CNBD) of mammalian hyperpolarization-activated cyclic nucleotide-gated (HCN) channels prevents their regulation by cAMP. Since TRIP8b is expressed exclusively in the brain, we envisage that it can be used for orthogonal control of HCN channels beyond the central nervous system. To this end, we have identified by rational design a 40-aa long peptide (TRIP8bnano) that recapitulates affinity and gating effects of TRIP8b in HCN isoforms (hHCN1, mHCN2, rbHCN4) and in the cardiac current If in rabbit and mouse sinoatrial node cardiomyocytes. Guided by an NMR-derived structural model that identifies the key molecular interactions between TRIP8bnano and the HCN CNBD, we further designed a cell-penetrating peptide (TAT-TRIP8bnano) which successfully prevented β-adrenergic activation of mouse If leaving the stimulation of the L-type calcium current (ICaL) unaffected. TRIP8bnano represents a novel approach to selectively control HCN activation, which yields the promise of a more targeted pharmacology compared to pore blockers.

scholarly journals Association with the Auxiliary Subunit PEX5R/Trip8b Controls Responsiveness of HCN Channels to cAMP and Adrenergic Stimulation

Neuron ◽  
2009 ◽  
Vol 62 (6) ◽  
pp. 814-825 ◽  
Author(s):  
Gerd Zolles ◽  
Daniela Wenzel ◽  
Wolfgang Bildl ◽  
Uwe Schulte ◽  
Andreas Hofmann ◽  
...  
Keyword(s):  
Hcn Channels ◽  
Adrenergic Stimulation ◽  
Auxiliary Subunit

Excitation, inhibition, and suppression by odors in isolated toad and rat olfactory receptor neurons

2000 ◽  
Vol 279 (1) ◽  
pp. C31-C39 ◽  
Author(s):  
Magdalena Sanhueza ◽  
Oliver Schmachtenberg ◽  
Juan Bacigalupo
Keyword(s):  
Firing Rate ◽  
Olfactory Receptor ◽  
Receptor Potential ◽  
Cell Voltage ◽  
Underlying Mechanism ◽  
Olfactory Receptor Neurons ◽  
Action Potential Firing ◽  
Potential Firing ◽  
A Cell ◽  
Receptor Neurons

Vertebrate olfactory receptor neurons (ORNs) exhibit odor-induced increases in action potential firing rate due to an excitatory cAMP-dependent current. Fish and amphibian ORNs also give inhibitory odor responses, manifested as decreases in firing rate, but the underlying mechanism is poorly understood. In the toad, an odor-induced Ca2+-activated K+ current is responsible for the hyperpolarizing receptor potential that causes inhibition. In isolated ORNs, a third manner by which odors affect firing is suppression, a direct and nonspecific reduction of voltage-gated and transduction conductances. Here we show that in whole cell voltage-clamped toad ORNs, excitatory or inhibitory currents were not strictly associated to a particular odorant mixture. Occasionally, both odor effects, in addition to suppression, were concurrently observed in a cell. We report that rat ORNs also exhibit odor-induced inhibitory currents, due to the activation of a K+ conductance closely resembling that in the toad, suggesting that this conductance is widely distributed among vertebrates. We propose that ORNs operate as complex integrator units in the olfactory epithelium, where the first events in the process of odor discrimination take place.

scholarly journals Enhanced Cytotoxicity through Conjugation of a “Clickable” Luminescent Re(I) Complex to a Cell-Penetrating Lipopeptide

2014 ◽  
Vol 5 (7) ◽  
pp. 809-814 ◽  
Author(s):  
Anna Leonidova ◽  
Vanessa Pierroz ◽  
Luke A. Adams ◽  
Nicholas Barlow ◽  
Stefano Ferrari ◽  
...  
Keyword(s):  
Cell Penetrating ◽  
A Cell

scholarly journals Zinc Enhances the Inhibitory Effects of Strychnine-Sensitive Glycine Receptors in Mouse Hippocampal Neurons

2007 ◽  
Vol 98 (6) ◽  
pp. 3666-3676 ◽  
Author(s):  
Hai Xia Zhang ◽  
Liu Lin Thio
Keyword(s):  
Action Potential ◽  
Action Potentials ◽  
Hippocampal Neurons ◽  
Neuronal Excitability ◽  
Hippocampal Slices ◽  
Glycine Receptors ◽  
Inhibitory Effects ◽  
Action Potential Firing ◽  
Embryonic Mouse ◽  
Potential Firing

Although extracellular Zn2+ is an endogenous biphasic modulator of strychnine-sensitive glycine receptors (GlyRs), the physiological significance of this modulation remains poorly understood. Zn2+ modulation of GlyR may be especially important in the hippocampus where presynaptic Zn2+ is abundant. Using cultured embryonic mouse hippocampal neurons, we examined whether 1 μM Zn2+, a potentiating concentration, enhances the inhibitory effects of GlyRs activated by sustained glycine applications. Sustained 20 μM glycine (EC25) applications alone did not decrease the number of action potentials evoked by depolarizing steps, but they did in 1 μM Zn2+. At least part of this effect resulted from Zn2+ enhancing the GlyR-induced decrease in input resistance. Sustained 20 μM glycine applications alone did not alter neuronal bursting, a form of hyperexcitability induced by omitting extracellular Mg2+. However, sustained 20 μM glycine applications depressed neuronal bursting in 1 μM Zn2+. Zn2+ did not enhance the inhibitory effects of sustained 60 μM glycine (EC70) applications in these paradigms. These results suggest that tonic GlyR activation could decrease neuronal excitability. To test this possibility, we examined the effect of the GlyR antagonist strychnine and the Zn2+ chelator tricine on action potential firing by CA1 pyramidal neurons in mouse hippocampal slices. Co-applying strychnine and tricine slightly but significantly increased the number of action potentials fired during a depolarizing current step and decreased the rheobase for action potential firing. Thus Zn2+ may modulate neuronal excitability normally and in pathological conditions such as seizures by potentiating GlyRs tonically activated by low agonist concentrations.

scholarly journals A cell-penetrating whole molecule antibody targeting intracellular HBx suppresses hepatitis B virus via TRIM21-dependent pathway

Theranostics ◽  
2018 ◽  
Vol 8 (2) ◽  
pp. 549-562 ◽  
Author(s):  
Jun-Fang Zhang ◽  
Hua-Long Xiong ◽  
Jia-Li Cao ◽  
Shao-Juan Wang ◽  
Xue-Ran Guo ◽  
...  
Keyword(s):  
Hepatitis B Virus ◽  
Hepatitis B ◽  
B Virus ◽  
Cell Penetrating ◽  
A Cell ◽  
Antibody Targeting ◽  
Dependent Pathway

scholarly journals The thalamic low-threshold Ca 2+ potential: a key determinant of the local and global dynamics of the slow (<1 Hz) sleep oscillation in thalamocortical networks

2011 ◽  
Vol 369 (1952) ◽  
pp. 3820-3839 ◽  
Author(s):  
Vincenzo Crunelli ◽  
Adam C. Errington ◽  
Stuart W. Hughes ◽  
Tibor I. Tóth
Keyword(s):  
Action Potential ◽  
Slow Oscillation ◽  
Global Dynamics ◽  
Action Potential Firing ◽  
Local And Global Dynamics ◽  
Up States ◽  
Potential Firing ◽  
Low Threshold

During non-rapid eye movement sleep and certain types of anaesthesia, neurons in the neocortex and thalamus exhibit a distinctive slow (<1 Hz) oscillation that consists of alternating UP and DOWN membrane potential states and which correlates with a pronounced slow (<1 Hz) rhythm in the electroencephalogram. While several studies have claimed that the slow oscillation is generated exclusively in neocortical networks and then transmitted to other brain areas, substantial evidence exists to suggest that the full expression of the slow oscillation in an intact thalamocortical (TC) network requires the balanced interaction of oscillator systems in both the neocortex and thalamus. Within such a scenario, we have previously argued that the powerful low-threshold Ca 2+ potential (LTCP)-mediated burst of action potentials that initiates the UP states in individual TC neurons may be a vital signal for instigating UP states in related cortical areas. To investigate these issues we constructed a computational model of the TC network which encompasses the important known aspects of the slow oscillation that have been garnered from earlier in vivo and in vitro experiments. Using this model we confirm that the overall expression of the slow oscillation is intricately reliant on intact connections between the thalamus and the cortex. In particular, we demonstrate that UP state-related LTCP-mediated bursts in TC neurons are proficient in triggering synchronous UP states in cortical networks, thereby bringing about a synchronous slow oscillation in the whole network. The importance of LTCP-mediated action potential bursts in the slow oscillation is also underlined by the observation that their associated dendritic Ca 2+ signals are the only ones that inform corticothalamic synapses of the TC neuron output, since they, but not those elicited by tonic action potential firing, reach the distal dendritic sites where these synapses are located.

Sign in / Sign up

Export Citation Format

Share Document